Patent Application
20170165396
The present disclosure is generally directed to absorbent articles for personal hygiene. The absorbent articles may each comprise a topsheet joined via a tackifier-free adhesive to a substrate to form a laminate.
Absorbent articles for personal hygiene, such as disposable diapers for infants, training pants for toddlers, adult incontinence undergarments, and/or sanitary napkins are designed to absorb and contain bodily exudates, in particular large quantities of urine, runny BM, and/or menses (together the “fluids”). These absorbent articles may comprise several layers providing different functions, for example, a topsheet, a backsheet, and an absorbent core disposed between the topsheet and the backsheet, among other layers, if desired.
The topsheet is generally liquid permeable and is configured to receive the fluids being excreted from the body and aid in directing the fluids toward an acquisition and/or distribution system and/or towards the absorbent core. In general, topsheets are made to be hydrophilic via a surfactant treatment applied thereto so that the fluids are attracted to the topsheet to then be channeled into the underlying acquisition and/or distribution system and/or the absorbent core. One of the important qualities of a topsheet is the ability to reduce ponding of the fluids on the topsheets before the fluids are able to be absorbed by the absorbent article. Stated another way, one design criteria of topsheets is to reduce the amount of time the fluids spend on the topsheets prior to being absorbed by the absorbent article. If the fluids remain on the surfaces of the topsheets for too long of a period of time, wearers may not feel dry and discomfort may increase.
To solve the problem of the wearer's skin feeling wet during, for example, a urination event, because of prolonged fluid residency on topsheets, apertured topsheets have been used to allow for faster fluid penetration into the absorbent article. Topsheets can be still further improved by providing three-dimensional substrates which further reduce skin/fluid contact and/or skin/fluid contact time during, for example, a urination event. It can be important to have the topsheet and adjacent substrate bonded via an adhesive that is very stable. Molten adhesives used in assembling articles are typically made by combining polymer with additive components in a substantially uniform thermoplastic blend. However, the additive components, such as tackifiers, for example, can migrate during product use and create instability issues that negatively affect the performance and consumer impression of the article. In addition, for some hot melt adhesives, tackifiers may be a significant portion of the overall formulation and/or the most expensive component in the hot melt adhesive. Furthermore, as many topsheets are coated with lotions or surfactants, use of a topsheet laminate that comprises low or substantially tackifier-free adhesives may reduce any interaction between a tackifier and the lotions and/or surfactants.
Accordingly, there is a need for adhesives used in topsheet laminates that have reduced amounts of tackifier or that are substantially free of tackifiers.
An absorbent article comprising a liquid permeable topsheet, a liquid impermeable backsheet, an absorbent core positioned at least partially intermediate the liquid permeable topsheet and the liquid impermeable backsheet, and a substrate positioned between the topsheet and the absorbent core; wherein the topsheet and the substrate are joined by an adhesive to form a laminate; wherein the laminate comprises a morphological treatment; and wherein the adhesive is a substantially tackifier-free adhesive.
The above-mentioned and other features and advantages of the present disclosure, and the manner of attaining them, will become more apparent and the disclosure itself will be better understood by reference to the following description of non-limiting examples of the disclosure taken in conjunction with the accompanying drawings, wherein:
The term “absorbent article, as used herein, refers to disposable devices such as infant, child, or adult diapers, sanitary napkins, adult incontinence products, pant-style diapers, training pants, diaper inserts, and the like which are placed against or in proximity to the body of the wearer to absorb and contain the bodily exudates (e.g., urine and BM) discharged from the body. Typically, these articles comprise a topsheet, backsheet, an absorbent core, optionally a LMS, and typically other components, with the absorbent core normally placed at least partially between the backsheet and the LMS (if provided) or between the topsheet and the backsheet. The absorbent articles of the present disclosure will be further illustrated in the below description and in the Figures in the form of a taped diaper. Nothing in this description should be, however, considered to limit the scope of the claims. As such the present disclosure applies to any suitable form of absorbent articles (e.g., training pants, taped diapers, adult incontinence products-in either taped or pant forms, sanitary napkins).
The term “nonwoven web”, as used herein, means a manufactured sheet, web, or batt of directionally or randomly orientated fibers, bonded by friction, and/or cohesion, and/or adhesion, excluding paper and products which are woven, knitted, tufted, stitch-bonded incorporating binding yarns or filaments, or felted by wet-milling, whether or not additionally needled. The fibers may be of natural or man-made origin and may be staple or continuous filaments or be formed in situ. Commercially available fibers may have diameters ranging from less than about 0.001 mm to more than about 0.2 mm and may come in several different forms such as short fibers (known as staple, or chopped), continuous single fibers (filaments or monofilaments), untwisted bundles of continuous filaments (tow), and twisted bundles of continuous filaments (yam). Nonwoven webs can be formed by many processes such as meltblowing, spunbonding, solvent spinning, electrospinning, carding, and airlaying. The basis weight of nonwoven webs is usually expressed in grams per square meter (g/m2 or gsm).
The terms “join”, “joined” “joining”, “bond”, “bonding”, “bonded”, “attach”, “attached”, or “attaching” as used herein, encompasses configurations whereby an element is directly secured to another element by affixing the element directly to the other element, and configurations whereby an element is indirectly secured to another element by affixing the element to intermediate member(s) which in turn are affixed to the other element.
The term “channel”, as used herein, is a region or zone in a material layer that has a substantially lower basis weight (e.g., less than 50%, less than 70%, less than 90%) than the surrounding material in the material layer. The channel may be a region in a material layer that is substantially material-free (e.g., 90% material-free, 95% material-free, or 99% material-free, or completely material-free). A channel may extend through one or more material layers. The channels generally have a lower bending modulus than the surrounding regions of the material layer, enabling the material layer to bend more easily and/or contain more bodily exudates within the channels than in the surrounding areas of the material layer. Thus, a channel is not merely an indentation in the material layer that does not create a reduced basis weight in the material layer in the area of the channel.
The term “geometric treatment”, as used herein, means at least a portion or region of a single or multi-layer substrate that comprises elements that are apertures of any suitable size and shape and/or elements that form a morphological treatment.
The term “morphological treatment”, as used herein, means at least a portion or region of a single or multi-layer substrate that comprises elements having three-dimensional features, embossments, interpenetration of one layer into or through another layer (e.g., one or more layers of the LMS into the topsheet or the topsheet into one or more layer of the LMS), out-of-plane bumps, out-of-plane ridges, out-of-plane tufts, out-of-plane pleats, out-of-plane ripples, or fold lines. A morphological treatment causes a substantially uniform planar substrate to be transformed from a first morphological configuration (generally flat and planar) to another morphological configuration (generally not flat and planar). The morphological treatment is formed of a plurality of the elements. For the avoidance of doubt, a morphological treatment does not include apertures, but an apertured material may be subjected to a morphological treatment.
The term “chemical treatment”, as used herein, means at least a portion or region of a single or multi-layer substrate that has a compound, composition, or substance applied to at least a portion thereof. Some examples are one or more skin care compositions, surfactants, inks, dyes, pigments, hydrophilic coatings, hydrophobic coatings, lotions, enzyme inhibitors, vitamins, and/or active ingredients. The chemical treatment may be sprayed on, printed on, slot coated, or otherwise applied to the at least a portion or region of the substrate.
The term “substantially durable”, as used herein, means a chemical treatment where at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99%, or more of the applied chemical treatment remains on the substrate from the time of manufacture throughout a typical period of intended use (e.g., from a point in time where an absorbent article is applied to a wearer to a point in time when the absorbent article is removed from the wearer and discarded).
The term “substantially transferrable”, as used herein, means a chemical treatment where at least 10%, at least 20%, at least 30%, at least 40%, at least 50%, or even at least 60% or more of the applied chemical treatment transfers to the skin of a wearer during a typical period of intended use (e.g., from a point in time where an absorbent article is applied to a wearer to a point in time when the absorbent article is removed from the wearer and discarded).
The term “hydrophilic coating”, as used herein, means a chemical treatment applied to a substrate to cause the substrate to become hydrophilic or more hydrophilic.
The term “hydrophilic”, as used herein, refers to a substrate or composition having a contact angle less than or equal to 90° according to The American Chemical Society Publication “Contact Angle, Wettability, and Adhesion,” edited by Robert F. Gould and copyrighted in 1964.
The term “hydrophobic coating”, as used herein, means a chemical treatment applied to a substrate to cause the substrate to become hydrophobic or more hydrophobic.
The term “hydrophobic”, as used herein, refers to a substrate or composition having a contact angle greater than or equal to 90° according to The American Chemical Society Publication “Contact Angle, Wettability, and Adhesion,” edited by Robert F. Gould and copyrighted in 1964.
The term “flow control material”, as used herein, may be a chemical treatment where a substance is applied to a substrate (such as a liquid permeable topsheet) that at least partially restricts, or fully restricts, the flow of bodily exudates therethrough. The flow control material may be a wax, an ink (having a pigment), a non-tack adhesive, a hot melt adhesive, a substantially durable component of a skin care composition, a polyolefin, a high molecular weight alcohol (one example of a component of a skin care composition), or other compositions substantially solid at 20 degrees C., for example. The flow control material may be substantially durable. The flow control material may also comprise when a material is applied to a substrate (e.g., a topsheet) and then the material and the substrate are run through two or more rolls to melt, join, bond, or attach the flow control material to the substrate.
The term “active ingredient”, as used herein, means an ingredient that has a chemical, biochemical, and/or biological effect—i.e., causes, initiates, or affects a change in a chemical, biochemical, and/or biological reaction, system, process, or equilibrium. This is opposed to inactive ingredients which may typically be used as carrier media, viscosity modifiers, melt temperature mediators, or for purely physical reasons (i.e., fillers).
The term “enzyme inhibitor”, as used herein, means a molecule, which binds to enzymes and decreases their activity.
As used herein, the term “elastic” refers to any material which, upon application of a biasing force, is stretchable, that is, elongatable, at least about 60 percent (i.e., to a stretched, biased length, which is at least about 160 percent of its relaxed unbiased length), and which, will recover at least 55 percent of its elongation upon release of the stretching, elongation force. A hypothetical example would be a one (1) inch sample of a material which is elongatable to at least 1.60 inches, and which, upon being elongated to 1.60 inches and released, will recover to a length of not more than 1.27 inches. Many elastic materials may be elongated by more than 60 percent (i.e., much more than 160 percent of their relaxed length), for example, elongated 100 percent or more, and many of these materials will recover to substantially their initial relaxed length, for example, to within 105 percent of their initial relaxed length, upon release of the stretch force.
As used herein, the term “nonelastic” refers to any material which does not fall within the definition of “elastic” above.
As used herein, the term “extensible” refers to any material which, upon application of a biasing force, is elongatable, at least about 50 percent, at least about 100%, or at least about 125%, without experiencing catastrophic failure.
As used herein, the term “melt-stabilized” refers to portions of a nonwoven material which have been subjected to localized heating and/or localized pressure to substantially consolidate the fibers of the nonwoven material into a stabilized film-like form.
The term “machine direction” (MD) is used herein to refer to the primary direction of material, strip of substrate, or article flow through a process.
The term “cross direction” (CD) is used herein to refer to a direction that is generally perpendicular to the machine direction.
As used herein “homopolymer” means a polymer resulting from the polymerization of a single monomer, i.e., a polymer consisting essentially of a single type of repeating unit.
As used herein, the term “copolymer(s)” refers to polymer(s) formed by the polymerization of at least two different monomers. For example, the term “copolymer” includes the copolymerization reaction product of a monomer such as propene or butene, preferably 1-butene and an alpha-olefin, such as for example, ethylene, 1-hexene or 1-octene.
As used herein, the term “propene copolymer” or “propylene copolymer” means a copolymer of greater than 40 or 50 wt. % or more propene and at least one monomer selected from the group including ethylene and a C4 to C20 α-olefin.
As used herein, the term “butene copolymer” means a polymer of n-butene (1-butene) or 2-butene and at least one monomer selected from the group of C2-3 and C5-20 alpha olefins. Butene copolymers typically comprise a minimum amount at least about 40 or about 50 wt. % or more of a butene monomer such as 1-butene.
The term “heterophase” polymer means a polymer having an amorphous character and at least some substantial crystalline content (at least 5 wt. %, 10 wt. %, 20 wt. %, 40 wt. % or 50 wt. % crystalline content) that can provide cohesive strength in the cooled adhesive mass. The crystalline content can be in the form of stereoregular blocks or sequences.
The term “amorphous” means the substantial absence of crystallinity, (i.e.) less than 5% and less than 1%.
The term “sequence or block” means a polymer portion of repeating monomer that is similar in composition, crystallinity or other aspect.
As used herein, the term “open time” means the amount of time elapsed between application of a molten hot melt adhesive composition to a first substrate, and the time when useful tackiness or wetting out of the adhesive on a substrate effectively ceases due to solidification of the adhesive composition. Open time is also referred to as “working time.”
As used herein, the term “substrate” means any item having at least a partially or fully solidified fiber or planar surface with which contact with a hot melt adhesive composition is intended. In some cases the same area, circle, bead, line, filament or dot of hot melt adhesive composition is contacted with two or more substrates for the purpose of creating an adhesive bond there between. In some such cases the substrates are part of the same item: for example, folded film or folded non-woven, two sides of a cardboard sheet folded over, wherein the two sides are adhesively bonded together. In other such cases the substrates are part of different items: for example, a plastic film that is adhesively bonded to a non-woven or cardboard sheet. The substrates can be impermeable, permeable, porous or nonporous.
As used herein, the term “substantially” means generally the same or uniform but allowing for or having minor fluctuations from a defined property, definition, etc. For example, small measurable or immeasurable fluctuations in a measured property described herein, such as viscosity, melting point, etc. may result from human error or methodology precision. Other fluctuations are caused by inherent variations in the manufacturing process, thermal history of a formulation, and the like. The adhesive compositions of the, nonetheless, would be said to be substantially having the property as reported.
As used herein, the term “major proportion” means that a material or monomer is used at greater than 50 wt. %. As used herein, the term “primary component” means that a material or monomer is the more common substance or has the higher concentration in the mixture or polymer compared to others but may not be as much as 50 wt. %.
The transitional phrase “consisting essentially of” limits the scope of a claim to the specified materials but includes those that do not materially affect the basic and novel characteristics of the claimed materials. These characteristics include open time, cohesive strength (tensile strength), peel strength and viscosity. Meaningful amounts of a third polymer or amounts of a tackifier materially affect the basic and novel characteristics of the claimed materials.
General Description of an Example Absorbent Article
An example absorbent article 20 according to the present disclosure, shown in the form of a diaper, is represented in
The absorbent article may comprise a liquid permeable topsheet 24, a liquid impermeable backsheet 25, an absorbent core 28 positioned at least partially intermediate the topsheet 24 and the backsheet 25, and barrier leg cuffs 34. The absorbent article may also comprise a liquid management system (“LMS”) 50 (shown in
The Figures also show typical taped diaper components such as a fastening system comprising adhesive tabs 42 or other mechanical fasteners attached towards the rear edge of the absorbent article 20 and cooperating with a landing zone 44 on the front of the absorbent article 20. The absorbent article may also comprise other typical elements, which are not represented, such as a rear elastic waist feature and a front elastic waist feature, for example.
The absorbent article 20 may comprise a front waist edge 10, a rear waist edge 12 longitudinally opposing the front waist edge 10, a first side edge 3, and a second side edge 4 laterally opposing the first side edge 3. The front waist edge 10 is the edge of the absorbent article 20 which is intended to be placed towards the front of the user when worn, and the rear waist edge 12 is the opposite edge. Together the front waist edge 10 and the rear waist edge form waist opening when the absorbent article 20 is donned on a wearer. The absorbent article 20 may have a longitudinal axis 80 extending from the lateral midpoint of the front waist edge 10 to a lateral midpoint of the rear waist edge 12 of the absorbent article 20 and dividing the absorbent article 20 in two substantially symmetrical halves relative to the longitudinal axis 80, with article placed flat and viewed from the wearer-facing surface as illustrated
The topsheet 24, the backsheet 25, the absorbent core 28, and the other article components may be assembled in a variety of configurations, in particular by gluing or heat embossing, for example, or by using the substantially tackifier-free adhesives described herein. Example diaper configurations are described generally in U.S. Pat. No. 3,860,003, U.S. Pat. No. 5,221,274, U.S. Pat. No. 5,554,145, U.S. Pat. No. 5,569,234, U.S. Pat. No. 5,580,411, and U.S. Pat. No. 6,004,306.
The absorbent core 28 may comprise an absorbent material comprising 75% to 100%, at least 80%, at least 85%, at least 90%, at least 95%, or at least 99%, all by weight, of the absorbent material, specifically reciting all 0.1% increments within the above-specified ranges and all ranges formed therein or thereby, and a core wrap enclosing the absorbent material. The core wrap may typically comprise two materials, substrates, or nonwoven materials 16 and 16′ (see
The absorbent core 28 may comprises one or more channels, represented in
Topsheet
The topsheet 24 is the part of the absorbent article that is directly in contact with the wearer's skin. The topsheet 24 may be joined to the backsheet 25, the core 28 and/or any other layers as is known to those of skill in the art. Usually, the topsheet 24 and the backsheet 25 are joined directly to each other in some locations (e.g., on or close to the periphery of the article) and are indirectly joined together in other locations by directly joining them to one or more other elements of the absorbent article 20, for example, with the substantially tackifier-free adhesives described herein.
The topsheet 24 may be compliant, soft-feeling, and non-irritating to the wearer's skin. Further, at least a portion of the topsheet 24 may be liquid permeable, permitting liquids to readily penetrate through its thickness. A suitable topsheet may be manufactured from a wide range of materials, such as porous foams, reticulated foams, apertured plastic films, or woven or nonwoven materials of natural fibers (e.g., wood or cotton fibers), synthetic fibers or filaments (e.g., polyester or polypropylene or bicomponent PE/PP fibers or mixtures thereof), or a combination of natural and synthetic fibers. If the topsheet 24 includes fibers, the fibers may be spunbond, carded, wet-laid, meltblown, hydroentangled, or otherwise processed as is known in the art, in particular spunbond PP nonwoven.
Typical absorbent article topsheets have a basis weight of from about 5 gsm to about 50 gsm, from about 10 to about 35 gsm or from about 12 to about 30 gsm, but other basis weights are within the scope of the present disclosure.
Backsheet
The backsheet 25 is generally that portion of the absorbent article 20 positioned adjacent the garment-facing surface of the absorbent core 28 and which prevents, or at least inhibits, the bodily exudates absorbed and contained therein from soiling articles such as bedsheets and undergarments. The backsheet 25 is typically impermeable, or at least substantially impermeable, to liquids (e.g., urine, running BM), but permeable to vapors to allow the diaper to “breath”. The backsheet may, for example, be or comprise a thin plastic film such as a thermoplastic film having a thickness of about 0.012 mm to about 0.051 mm. Example backsheet films include those manufactured by Tredegar Corporation, based in Richmond, Va., and sold under the trade name CPC2 film. Other suitable backsheet materials may include breathable materials which permit vapors to escape from the absorbent article 20 while still preventing, or at least inhibiting, bodily exudates from passing through the backsheet 25. Example breathable materials may include materials such as woven webs, nonwoven webs, composite materials such as film-coated nonwoven webs, microporous films, and monolithic films.
The backsheet 25 may be joined to the topsheet 24, the absorbent core 28, and/or any other element of the absorbent article 20 by any attachment methods known to those of skill in the art.
Suitable attachment methods are described above with respect to methods for joining the topsheet 24 to other elements of the absorbent article 20, and include, for example, adhering with the substantially tackifier-free adhesives described herein.
Absorbent Core
As used herein, the term “absorbent core” refers to the individual component of the absorbent article having the most absorbent capacity and that comprises an absorbent material. The absorbent core may comprise a core wrap or core bag (hereafter “core wrap”) enclosing the absorbent material. The term “absorbent core” does not include the LMS or any other component of the absorbent article which is not either integral part of the core wrap or placed within the core wrap. The absorbent core may comprise, consist essentially of, or consist of, a core wrap, absorbent material as defined below, and glue enclosed within the core wrap. Pulp or air-felt may also be present within the core wrap and may form a portion of the absorbent material. The absorbent core periphery, which may be the periphery of the core wrap, may define any suitable shape, such as a “T,” “Y,” “hour-glass,” or “dog-bone” shape, for example. An absorbent core periphery having a generally “dog bone” or “hour-glass” shape may taper along its width towards the middle or “crotch” region of the core. In this way, the absorbent core may have a relatively narrow width in an area of the absorbent core intended to be placed in the crotch region of an absorbent article.
The absorbent core 28 of the present disclosure may comprise an absorbent material with a high amount of superabsorbent polymers (herein abbreviated as “SAP”) enclosed within a core wrap. The SAP content may represent 70% to 100% or at least 70%, 75%, 80%, 85%, 90%, 95%, 99%, or 100% by weight of the absorbent material contained in the core wrap. The SAP useful with the present disclosure may include a variety of water-insoluble, but water-swellable polymers capable of absorbing large quantities of fluids. The core wrap is not considered as absorbent material for the purpose of assessing the percentage of SAP in the absorbent core. The remainder of the absorbent material in the core 28 may be air-felt.
“Absorbent material” means a material which has some absorbency property or liquid retaining properties, such as SAP, cellulosic fibers as well as synthetic fibers. Typically, glues used in making absorbent cores have no absorbency properties and are not considered as absorbent material. The SAP content may be higher than 80%, for example at least 85%, at least 90%, at least 95%, at least 99%, and even up to and including 100% of the weight of the absorbent material contained within the core wrap, as stated above. This provides a relatively thin core compared to conventional cores typically comprising between 40-60% SAP, for example, and high content of cellulose fibers or airfelt. The absorbent material may comprise less than 15% or less than 10% weight percent of natural or synthetic fibers, less than 5% weight percent, less than 3% weight percent, less than 2% weight percent, less than 1% weight percent, or may even be substantially free of, or free of, natural and/or synthetic fibers, specifically reciting all 0.1% increments within the specified ranges and all ranges formed therein or thereby. The absorbent material may comprise little or no airfelt (cellulose) fibers, in particular the absorbent core may comprise less than 15%, 10%, 5%, 3%, 2%, 1% airfelt (cellulose) fibers by weight, or may even be substantially free of, or free of, cellulose fibers, specifically reciting all 0.1% increments within the specified ranges and all ranges formed therein or thereby.
The example absorbent core 28 of the absorbent article of
Cores comprising relatively high amount of SAP with various core designs are disclosed in U.S. Pat. No. 5,599,335 (Goldman), EP 1,447,066 (Busam), WO 95/11652 (Tanzer), U.S. Pat. Publ. No. 2008/0312622A1 (Hundorf), and WO 2012/052172 (Van Malderen).
The absorbent material may be one or more continuous layers present within the core wrap. Alternatively, the absorbent material may be comprised of individual pockets or stripes of absorbent material enclosed within the core wrap. In the first case, the absorbent material may be, for example, obtained by the application of a single continuous layer of absorbent material. The continuous layer of absorbent material, in particular of SAP, may also be obtained by combining two or more absorbent layers having discontinuous absorbent material application pattern, wherein the resulting layer is substantially continuously distributed across the absorbent particulate polymer material area, as disclosed in U.S. Pat. Appl. Publ. No. 2008/0312622A1 (Hundorf), for example. The absorbent core 28 may comprise a first absorbent layer and a second absorbent layer. The first absorbent layer may comprise the first material 16 and a first layer 61 of absorbent material, which may be 100% or less of SAP. The second absorbent layer may comprise the second material 16′ and a second layer 62 of absorbent material, which may also be 100% or less of SAP. The absorbent core 28 may also comprise a fibrous thermoplastic adhesive material 51 at least partially bonding each layer of absorbent material 61, 62 to its respective material 16 or 16′. This is illustrated in FIGS. 7-8, as an example, where the first and second SAP layers have been applied as transversal stripes or “land areas” having the same width as the desired absorbent material deposition area on their respective substrate before being combined. The stripes may comprise different amount of absorbent material (SAP) to provide a profiled basis weight along the longitudinal axis of the core 80. The first material 16 and the second material 16′ may form the core wrap.
The fibrous thermoplastic adhesive material 51 may be at least partially in contact with the absorbent material 61, 62 in the land areas and at least partially in contact with the materials 16 and 16′ in the junction areas. This imparts an essentially three-dimensional structure to the fibrous layer of thermoplastic adhesive material 51, which in itself is essentially a two-dimensional structure of relatively small thickness, as compared to the dimension in length and width directions. Thereby, the fibrous thermoplastic adhesive material may provide cavities to cover the absorbent material in the land area, and thereby immobilizes this absorbent material, which may be 100% or less of SAP.
Core Wrap
The core wrap may be made of a single substrate, material, or nonwoven folded around the absorbent material, or may comprise two (or more) substrates, materials, or nonwovens which are attached to another. Typical attachments are the so-called C-wrap and/or sandwich wrap. In a C-wrap, as illustrated, for example, in
The core wrap may be at least partially sealed along all the sides of the absorbent core so that substantially no absorbent material leaks out of the core. By “substantially no absorbent material” it is meant that less than 5%, less than 2%, less than 1%, or about 0% by weight of absorbent material escape the core wrap. The term “seal” is to be understood in a broad sense. The seal does not need to be continuous along the whole periphery of the core wrap but may be discontinuous along part or the whole of it, such as formed by a series of seal points spaced on a line. A seal may be formed by gluing and/or thermal bonding.
The core wrap may also be formed by a single substrate which may enclose as in a parcel wrap the absorbent material and be sealed along the front side and rear side of the core and one longitudinal seal.
SAP Deposition Area
The absorbent material deposition area 8 may be defined by the periphery of the layer formed by the absorbent material 60 within the core wrap, as seen from the top side of the absorbent core. The absorbent material deposition area 8 may have various shapes, in particular, a so-called “dog bone” or “hour-glass” shape, which shows a tapering along its width towards the middle or “crotch” region of the core. In this way, the absorbent material deposition area 8 may have a relatively narrow width in an area of the core intended to be placed in the crotch region of the absorbent article, as illustrated in
Channels in the Absorbent Core
The absorbent material deposition area 8 may comprise at least one channel 26, which is at least partially oriented in the longitudinal direction of the absorbent article 80 (i.e., has a longitudinal vector component). Other channels may be at least partially oriented in the lateral direction (i.e., has a lateral vector component) or in any other direction. In the following, the plural form “channels” will be used to mean “at least one channel”. The channels may be circular, oblong, or be in the shape of a variety of other closed polygons. The channels may be formed in various ways. For example, the channels may be formed by zones within the absorbent material deposition area 8 which may be substantially free of, or free of, absorbent material, in particular, SAP. In addition or alternatively, the channels may also be formed by continuously or discontinuously bonding the top side of the core wrap to the bottom side of the core wrap through the absorbent material deposition area 8. The channels may be continuous or intermittent. The liquid management system 50, or another layer of the absorbent article, may also comprise channels, which may or not correspond to the channels of the absorbent core, as described in more detail below.
The absorbent core 28 may comprise more than two channels, for example, at least 3, at least 4, etc. Shorter channels may also be present, for example in the rear waist region 6 or the front waist region 5 of the core as represented by the pair of channels 27, 27′ in
At least some or all of the channels may be permanent channels, meaning their integrity is at least partially maintained both in the dry state and in the wet state. Permanent channels may be obtained by provision of one or more adhesive materials, for example, the fibrous layer of adhesive material or construction glue that helps adhere a substrate with an absorbent material within the walls of the channel. Permanent channels may also be formed by bonding the upper side and lower side of the core wrap (e.g., the first substrate 16 and the second substrate 16′) and/or the topsheet 24 to the backsheet 25 together through the channels. Typically, an adhesive may be used to bond both sides of the core wrap or the topsheet and the a backsheet through the channels, but it is possible to bond via other known processes, such as pressure bonding, ultrasonic bonding, heat bonding, or combination thereof. Any of the adhesives used in the core may be the substantially tackifier-free adhesives described herein. The core wrap or the topsheet 24 and the backsheet 25 may be continuously bonded or intermittently bonded along the channels. The channels may advantageously remain or become visible at least through the topsheet and/or backsheet when the absorbent article is fully loaded with a fluid. This may be obtained by making the channels substantially free of SAP, so they will not swell, and sufficiently large so that they will not close when wet. Furthermore, bonding the core wrap to itself or the topsheet to the backsheet through the channels may be advantageous.
Absorbent cores and/or LMSs without any channels are also within the scope of the present disclosure. These cores may include airfelt-free cores, SAP/pulp cores, pulp cores, or other cores known to those of skill in the art.
Barrier Leg Cuffs
The absorbent article may comprise a pair of barrier leg cuffs 34. Each barrier leg cuff may be formed by a piece of material which is bonded to the absorbent article so it can extend upwards from the inner surface of the absorbent article and provide improved containment of liquids and other bodily exudates approximately at the junction of the torso and legs of the wearer. The barrier leg cuffs 34 are delimited by a proximal edge 64 joined directly or indirectly to the topsheet 24 and/or the backsheet 25 and a free terminal edge 66, which is intended to contact and form a seal with the wearer's skin. The barrier leg cuffs 34 extend at least partially between the front waist edge 10 and the rear waist edge 12 of the absorbent article on opposite sides of the longitudinal axis 80 and are at least present in the crotch region 7. The barrier leg cuffs 34 may be joined at the proximal edge 64 with the chassis of the absorbent article by a bond 65 which may be made by gluing, fusion bonding, or combination of other suitable bonding processes. The bond 65 at the proximal edge 64 may be continuous or intermittent. The bond 65 closest to the raised section of the leg cuffs 34 delimits the proximal edge 64 of the standing up section of the leg cuffs 34.
The barrier leg cuffs 34 may be integral with the topsheet 24 or the backsheet 25 or may be a separate material joined to the absorbent article's chassis. The material of the barrier leg cuffs 34 may extend through the whole length of the diapers but may be “tack bonded” to the topsheet 24 towards the front waist edge 10 and rear waist edge 12 of the absorbent article so that in these sections the barrier leg cuff material remains flush with the topsheet 24.
Each barrier leg cuff 34 may comprise one, two or more elastic strands or strips of film 35 close to this free terminal edge 66 to provide a better seal.
In addition to the barrier leg cuffs 34, the absorbent article may comprise gasketing cuffs 32, which are joined to the chassis of the absorbent article, in particular to the topsheet 24 and/or the backsheet 25 (may be joined with the substantially tackifier-free adhesives described herein) and are placed externally relative to the barrier leg cuffs 34. The gasketing cuffs 32 may provide a better seal around the thighs of the wearer. Each gasketing leg cuff may comprise one or more elastic strings or elastic elements in the chassis of the absorbent article between the topsheet 24 and backsheet 25 in the area of the leg openings. All or a portion of the barrier leg and/or gasketing cuffs may be treated with a lotion or skin care composition. The barrier leg cuffs may be constructed in a number of different configurations, including those described in U.S. Pat. App. Publ. No. 2012/0277713.
Front and Rear Ears
In a form, the absorbent article may comprise front ears 46 and rear ears 40. The ears may be an integral part of the chassis, such as formed from the topsheet 24 and/or backsheet 25 as side panel. Alternatively, as represented on
Liquid Management System (LMS)
One function of the LMS 50 is to quickly acquire the fluid and distribute it to the absorbent core 28 in an efficient manner. The LMS 50 may comprise one or more layers, which may form a unitary layer or may remain as discrete layers which may be attached to each other (for example, with the substantially tackifier-free adhesives described herein). The LMS 50 may comprise two layers: a distribution layer 54 and an acquisition layer 52 disposed between the absorbent core and the topsheet, but the present disclosure is not limited to such a configuration.
The LMS 50 may comprise SAP as this may slow the acquisition and distribution of the fluid. In other forms, the LMS may be substantially free (e.g., 80%, 85%, 90%, 95%, or 99% free of) or completely free of SAP. The LMS may also comprise one or more of a variety of other suitable types of materials, such as opened-cell foam, air-laid fibers, or carded, resin bonded nonwoven materials, for example. Suitable example LMSs are described in WO 2000/59430 (Daley), WO 95/10996 (Richards), U.S. Pat. No. 5,700,254 (McDowall), and WO 02/067809 (Graef), for example.
Distribution Layer
The LMS 50 may comprise a distribution layer 54. The distribution layer 54 may comprise at least 50% or more by weight of cross-linked cellulose fibers, for example. The cross-linked cellulosic fibers may be crimped, twisted, or curled, or a combination thereof including crimped, twisted, and curled. This type of material is disclosed in U.S. Pat. Publ. No. 2008/0312622 A1 (Hundorf).
Acquisition Layer
The LMS 50 may alternatively or additionally comprise an acquisition layer 52. The acquisition layer 52 may be disposed, for example, between the distribution layer 54 and the topsheet 24. The acquisition layer 52 may be or may comprise a non-woven material, such as an SMS or SMNIS material, comprising a spunbonded, a melt-blown and a further spunbonded layer or alternatively a carded chemical-bonded nonwoven. The acquisition layer 52 may comprise air or wet-laid cellulosic, cross-linked cellulosic, or synthetic fibers, or blends thereof. The acquisition layer 52 may comprise a roll-stock web of synthetic fibers (which may be processed to increase void space, such as by solid state formation), or a combination of synthetic and cellulosic fibers, bonded together to form a highloft material. Alternatively, the acquisition layer 52 may comprise absorbent open cell foam. The nonwoven material may be latex bonded.
Channels in Liquid Management System
The LMS 50 of the absorbent article 20 may comprise channels that may generally enable better conformation of the absorbent article to the wearer's anatomy, leading to increased freedom-of-movement and reduced gapping. One or more of the channels of the LMS 50 may be configured to work in concert with various channels in the absorbent core 28, as discussed above. Furthermore, channels in the LMS 50 may also provide increased void space to hold and distribute urine, BM or other bodily exudates within the absorbent article, leading to reduced leakage and skin contact. Channels in the LMS 50 may also provide internal serviceable indicia, especially when highlighted via physical differences in texture, color, and/or pattern, to facilitate achieving the correct alignment of the absorbent article on a wearer. Thus, such physical differences may be, for example, visually and/or tactilely noticeable.
Similar to the channels in the absorbent core 28, a channel in the LMS 50 may be any region in a layer, or extending through more than one layer, that has a substantially lower basis weight or thickness than the surrounding material, as set forth in the definition of “channel” above. The channels in the LMS 50 may also serve to reduce the tension forces to enable controlled bending and maintain the LMS 50 in close proximity to the absorbent core 28. Thus, the presence of channels in the LMS 50, which may or may not be aligned with any channels in an underlying absorbent core 28, may generally function as hinges to allow for a more flexible composite structure. In some cases, for example, the channels of the LMS 50 allow for the LMS 50 to move toward the absorbent core 28 in a controlled bending arrangement, thereby limiting the separation between the LMS 50 and the absorbent core 28. Moreover, a channel in the LMS 50 may assist in the routing of fluid or other bodily exudates from one region of the absorbent article 20 to another region of the absorbent article 20. Such routing may desirably improve the overall distribution of fluid through the absorbent article 20 and may lead to increase in comfort, wearability, or longevity of the article.
For multi-layered LMSs, the channels may be present in one or more layers of the LMS 50 and may vary in their dimensions in all three planes of reference. The width of a given channel in the LMS 50 may vary in the longitudinal direction (i.e., in a direction substantially parallel to the longitudinal axis of the absorbent article). A channel may also have a different width, length, and/or volume in front of a lateral axis or lateral separation element of the absorbent article than behind the lateral axis or lateral separation element. The channels of the LMS 50 may have a range of widths, lengths, shapes, volumes, and patterns, similar to the channels described above with regard to the absorbent core 28.
One or more channels in the LMS 50 may at least partially overlap, or fully overlap, a channel in the absorbent core 28, creating a deeper recess in the overlapping regions. For forms where the LMS 50 includes more than one layer, the layer closest to the absorbent core 28 may include a channel. One or more layers in the structure, such as the topsheet 24, an acquisition layer 52, distribution layer 54, or other layers, may be bonded to an element of the absorbent core 28 in this region to increase the depth of the combined channel. In a form, the channel in the acquisition layer 52 of the LMS 50 and the channel in the absorbent core 28 are coincident such that the channels are completely overlapping. In another form, channels in the LMS and storage layers have no overlapping area. Other forms have a vertical overlap between the channels in the two layers that encompass the intervening range such that they partially overlap.
Referring again to
The channels of the LMS 50 may be present at least at the same longitudinal level as the lateral axis 90 in the absorbent article, as represented in
The LMS 50 may define any suitable number of channels, such as at least one or more than two channels. Shorter channels may also be present, for example in the rear waist region 6 or the front waist region 5 of the LMS 50. The channels of the LMS 50 may comprise one or more pairs of channels symmetrically arranged, or otherwise arranged relative to the longitudinal axis 80 and/or the lateral axis 90, or other transverse axis. The channels may extend substantially longitudinally or substantially laterally.
At least some or all of the channels in the LMS 50 may be permanent channels, meaning their integrity is at least partially maintained both in the dry state and in the wet state. Permanent channels may be obtained by provision of one or more adhesive materials, for example, the fibrous layer of adhesive material or construction glue that helps adhere a substrate with an absorbent material within the walls of the channel. Permanent channels may also be formed by bonding the topsheet 24 to the backsheet 25 together through a channel of the LMS 50. Typically, an adhesive may be used to bond the topsheet 24 and the backsheet 25 through the channels, but it is possible to bond via other known processes, such as pressure bonding, ultrasonic bonding, heat bonding, or combination thereof. The topsheet 24 and the backsheet 25 may be continuously bonded or intermittently bonded along or within portions of or all of the channels.
In a form, referring to
The example LMS 50 of the absorbent article of
While portions of the channels 26, 26′ of the absorbent core 28 and the channels 49, 49′ of the LMS 50 shown in
Substantially Laterally-Extending Separation Element
A wearer-facing surface, or topsheet, of an absorbent article may have a visual front portion and a visual back portion. The visual front portion and the visual back portion may be separated by a substantially laterally-extending separation element 100. The term “substantially laterally” means within +/−15 degrees from a direction parallel to the lateral axis. The substantially laterally-extending separation element 100 may be, for example, a graphical indicia printed on the topsheet of the absorbent article, or other layer of the absorbent article (e.g., LMS 50), that is visible through the topsheet. The substantially laterally-extending separation element 100 may also be a portion of a tinted layer that is visible through the wearer-facing surface of the topsheet or the end of an underlying layer that has a different color than the topsheet. Alternatively or additionally, the visual front portion may be visually distinct from the visual back portion based on a color difference and/or a printed pattern difference. Such visual separation between the visual front portion and the visual back portion may help for proper alignment of the absorbent article during its application and help the appearance of separate zones configured for urine management and, separately, for BM management.
The substantially laterally-extending separation element 100, in various forms, may comprise a structural separator that is located in the region of the absorbent article generally corresponding to the perineal region of the wearer (i.e., disposed between the urethra and the anus). The structural separator may, for example, prevent, or at least somewhat inhibit, the surface migration of urine to the back of the absorbent article and BM to the front of the absorbent article. A structural separator may include any three-dimensional feature or component that functions as a transverse or laterally extending barrier (“TVB”), such as one or more projections above the wearer-facing surface of the absorbent article, recesses below the plane of the wearer-facing surface, and combinations thereof. One example includes a substantially laterally-oriented web or sheet that is attached to the wearer-facing surface of the absorbent article and that is attached on its ends to the barrier leg cuffs. Attachment to the barrier leg cuffs and the wearer-facing surface may provide a “seal” created by the TVB with respect to the front and back regions of the absorbent article to prevent, or at least inhibit, bodily exudates flow between the regions. The separator may be bonded to any other substrate via a substantially tackifier-free adhesive.
The structural separator may be rectangular or square when laid out flat in a relaxed, contracted state onto an even horizontal surface. The structural separator may also be trapezoidal when laid out flat in a relaxed, contracted state onto an even horizontal surface. The structural separator may be hydrophobic (e.g., it may be hydrophilic and made hydrophobic with a hydrophobic coating, for example a wax or a hydrophobic surface coating comprising one or more silicone polymers or fluorinated polymers.) The structural separator may have an elastic behavior such that it can be significantly elastically extensible in a lateral, transverse direction or other direction. The structural separator may have a certain tension during wear of the absorbent article to ensure that the structural separator forms an effective separator (barrier) with a Z-direction dimension, to avoid, or at least inhibit, migration of feces from the back to the front of the structural separator. Other structural separators may include raised or thicker portions of the topsheet, elements of the LMS or absorbent core, separately applied elements, or holes or depressions in one or more of the absorbent core elements or LMS.
Further to the above, the structural separator may have any suitable structure and may be a ridge, bump, and/or flap, for example. Some example cross-sectional views of substantially laterally-extending separation elements 100 configurations in the form of structural separators are illustrated in
Substrates, such as topsheets and/or LMS, for example, may have one or more zones in different regions or areas of the substrates. The zones may take on a variety of configurations, sizes, and shapes, and the zones, or portions thereof, may comprise chemical, geometric, and/or morphological treatments or, a particular zone may not comprise treatments at all. The zones or portions thereof may comprise flow control materials. The various treatments will be discussed below in greater detail below. Apertures may be created via punching, slitting, hydroforming, or overbonding followed by ring rolling. 3D structures may be formed with various solid state formation technologies, such as SELFing, IPS, or rIPS. Examples of zones and the various treatments for the zones, including geometric treatments, morphological treatments, chemical treatments, and flow control materials, include those described in U.S. Ser. No. 14/680,426.
Morphological Treatments
Example morphological treatments are provided in
The morphological treatments of
Referring to
Referring generally to
If two or more substrates are provided in a face-to-face relationship, the substrates may be nested, or at least partially nested, with each other in the three-dimensional protrusions 1032. In an example, a topsheet may be nested into an acquisition layer or the acquisition layer may be nested into the topsheet. Likewise, any other two or more substrates may be nested together in a similar fashion. For structures with two or more substrates, the basis weight distribution (concentration of fibers) within the protrusions 1032 may be different between the substrates. Portions of one substrate may be engaged by projections (1068) of a male roll 1062 and portions of the other substrate may be engaged into recesses (1072) of a female roll (see
Referring to
Referring to
As illustrated as an example in
Patterns of Apertures
Patterns of apertures may be provided in one or more substrates. The substrates may comprise one or more layers of a material, such as a two layer topsheet, or a topsheet and an acquisition material that are adhesively bonded together. The patterns of apertures may be within one or more zones.
Referring to
The patterns of apertures may comprise a first aperture 2002 having a first longitudinal axis, LA1, and a second aperture 2004 having a second longitudinal axis, LA2. The first longitudinal axis, LA1, may extend in a first direction and the second longitudinal axis, LA2, may extend in a second, different direction. The third aperture 2006 may have a third longitudinal axis, LA3. The third longitudinal axis, LA3, may extend in a third direction that is different than the first direction and the second direction.
The patterns of apertures illustrated in
The patterns of apertures of the present disclosure may be made generally by using the process generally described in U.S. Pat. No. 5,628,097 entitled “Method for Selectively Aperturing a Nonwoven Web” which issued May 13 1997 and U.S. Patent Publication 2003/0021951 entitled “High Elongation Apertured Nonwoven Web and Method of Making” which published Jan. 20th, 2003. The process is further described in U.S. Ser. No. 14/680,426. Other methods of producing substrates comprising patterns of apertures known to those of skill in the art are also within the scope of the present disclosure.
Three-Dimensional Substrates [13227MQ]
Some embodiments of the present disclosure may relate to three-dimensional substrates that may be applied to topsheets of absorbent articles, form portions of, or all of, the topsheets, or form other portions of absorbent articles. The three-dimensional substrates may be liquid permeable substrates. The three-dimensional substrates of the present disclosure may reduce fluid/skin contact and/or fluid/skin contact time by providing first elements having a first z-directional height and at least second elements having a second z-directional height. These substrates may also comprise apertures. The first z-directional height may generally be higher than the second z-directional height. Such a structure creates a substrate having a plurality of heights. These three-dimensional substrates may allow fluids, during a urination event, for example, to be received onto the substrate and moved into the second elements having the second z-directional height (lower) and/or into and through the apertures to at least reduce the amount of fluid in contact with the skin and/or to at least reduce the fluid/skin contact time. Stated another way, the first elements having the first z-directional height (higher) may be in contact with the skin, while the fluids moves via gravity into the second elements having the second z-directional height (lower height) and/or into and through the apertures. Upon information and belief, such three-dimensional structures reduce the amount of fluid on skin, give the wearer a drier, more comfortable feel, and/or reduce the pendency of fluid/skin contact. The first elements having the first z-directional height (higher) essentially serve to provide a spacer between the skin and the fluids while the substrates are channeling the fluids into the acquisition and/or distribution system and/or the absorbent core.
The three-dimensional, liquid permeable substrates of the present disclosure may comprise substrates that have first elements (e.g., projections) that have a first z-directional height and at least second elements (e.g., land areas) that have a second z-directional height. The substrates may also have a plurality of apertures. The substrates may also have at least third elements having at least a third z-directional height. Owing to such structures, fluids may be quickly moved away from the skin of a wearer, leaving primarily the first elements having the first z-directional heights contacting the skin of the wearer, thereby making the wearer feel dryer. The fluids may flow via gravity or via capillary gradient into the second elements having the second z-directional heights and/or into and through the apertures, so that the fluids may be absorbed into the absorbent articles. By providing the three-dimensional substrates of the present disclosure, fluid/skin contact and the time that fluids are in contact with the skin of a wearer may be reduced. Further, the first elements having the first z-directional heights may act as a spacer between the fluids and the skin of the wearer while the fluids are being absorbed into the absorbent article.
A three-dimensional, liquid permeable substrate (referred to herein both as a three-dimensional substrate or a liquid permeable substrate) may be on an absorbent article. In one form, the liquid permeable substrate, or other liquid permeable substrates described herein, may comprise a patch or strip positioned on and/or joined to a topsheet of the absorbent article. The patch or strip may be bonded to the topsheet, adhesively attached to the topsheet (such as by a substantially tackifier-free adhesive as described herein), cold-pressure welded to the topsheet, ultrasonically bonded to the topsheet, and/or otherwise joined to the topsheet. Alternatively, the liquid permeable substrates of the present disclosure may comprise the topsheet (e.g., topsheet 24), form all of the topsheet, or form a portion of the topsheet. Also, the topsheet 24 may be comprised only of one or more of the liquid permeable substrates of the present disclosure. In any of the various configurations, the liquid permeable substrates of the present disclosure are intended to form at least a portion of the wearer-facing surface of an absorbent article and be in at least partial contact with the skin of a wearer.
Referring to
Although the patch or strip of the liquid permeable substrate 400 is illustrated as being rectangular in
The liquid permeable substrate may comprise one or more layers. If more than one layer is provided, the layers may be joined together or attached to each other through mechanical bonding, adhesive bonding with, for example, the substantially tackifier-free adhesives described herein), pressure bonding, heat bonding, passing heated air through both layers, or by other methods of joining to form the multilayer substrate. The first layer may comprise one or more hydrophobic materials, or may be fully hydrophobic, and the second layer may comprise one or more hydrophilic materials, or may be fully hydrophilic. Instead of one layer comprising a hydrophobic material and the other layer comprising a hydrophilic material, one layer may comprise a material that is more hydrophobic or more hydrophilic than the material that comprises the other layer (e.g., both layers are hydrophilic, but one layer is more hydrophilic or both layers are hydrophobic, but one layer is more hydrophobic). The first layer may comprise a hydrophobic layer and the second layer may comprise a hydrophilic layer or vice versa. The first layer may be used as a portion of, or all of, the wearer-facing surface of the absorbent article. Alternatively, the second layer may be used as a portion of, or all of, the wearer-facing surface of the absorbent article.
The rationale for having the first layer (or wearer-facing layer) being comprised of a hydrophobic material is twofold. First, if the liquid permeable substrate is apertured, the hydrophobic layer will not retain as much liquid as the hydrophilic second layer and thus, there will be less fluid (e.g., urine) in direct contact with the skin of a wearer. Second, projections (described below) in the first and second layers generally form hollow portions or arches on a garment-facing side of the liquid permeable substrate that do not have direct contact with the ADS or core, so fluids can get caught in the hollow arches. Without good connectivity of the hollow arches to the ADS or the core, the liquid permeable substrate may retain more fluid and feel wetter to the wearer. With a hydrophobic first layer, however, any liquid that is wicked into the hollow arches will be mostly on the garment-facing, or downward-facing hydrophilic side of the liquid permeable substrate, thereby leaving the first hydrophobic layer dryer. In principle, this may be achieved with a hydrophilic or capillary gradient from the first layer to the second layer (e.g. finer fibers in the second layer with same hydrophilic properties (i.e., contact angle with the liquid)). The apertures in the substrate may play an important role to enable initial and fast fluid flow (strike-through) despite the first hydrophobic layer. Therefore, the first hydrophobic layer works in concert with the protrusions, hollow arches, and the apertures to reduce wetness on the wearer-facing surface of the liquid permeable substrate. In other instances, the second layer may be used as a portion of the wearer-facing surface.
The first layer may comprise a plurality of first fibers and/or filaments (hereafter together referred to as fibers). The plurality of first fibers may comprise fibers that are the same, substantially the same, or different in size, shape, composition, denier, fiber diameter, fiber length, and/or weight. The second layer may comprise a plurality of second fibers. The plurality of second fibers may comprise fibers that are the same, substantially the same, or different in size, shape, composition, denier, fiber diameter, fiber length, and/or weight. The plurality of first fibers may be the same as, substantially the same as, or different than the plurality of second fibers. Additional layers may have the same or different configurations.
The first layer and/or the second layer may comprise bicomponent fibers having a sheath and a core. The sheath may comprise polyethylene and the core may comprise polyethylene terephthalate (PET). The sheath and the core may also comprise any other suitable materials known to those of skill in the art. The sheath and the core may each comprise about 50% of the fibers by weight of the fibers, although other variations (e.g., sheath 60%, core 40%; sheath 30%, core 70% etc.) are also within the scope of the present disclosure. The bicomponent fibers or other fibers that make up the first and/or second layers may have a denier in the range of about 0.5 to about 6, about 0.75 to about 4, about 1.0 to about 4, about 1.5 to about 4, about 1.5 to about 3, about 1.5 to about 2.5, or about 2, specifically including all 0.1 denier increments within the specified ranges and all ranges formed therein or thereby. Denier is defined as the mass in grams per 9000 meters of a fiber length. In other instances, the denier of the fibers of the first layer may be in the range of about 1.5 denier to about 6 denier or about 2 denier to about 4 denier and the denier of the fibers of the second layer may be in the range of about 1.2 denier to about 3 denier or about 1.5 denier to about 3 denier, specifically reciting all 0.1 denier increments within the specified ranges and all ranges formed therein or thereby. In certain instances, the fibers of the first layer may be at least 0.5 denier, at least 1 denier, at least 1.5 denier, or at least 2 denier greater than the denier of the fibers of the second layer depending at least in part on the particular acquisition and/or distribution system in use in a certain absorbent article. By providing the fibers of the first layer with a denier higher than a denier of the fibers of the second layer, a pore gradient is provided in the liquid permeable substrate. This pore gradient may provide better dryness and/or acquisition in the liquid permeable substrate. The fibers having the larger denier in the first layer provide larger pores than the fibers having the smaller denier in the second layer, thereby producing the pore gradient between the layers.
The plurality of first and second fibers may also comprise any other suitable types of fibers, such as polypropylene fibers, other polyolefins, other polyesters besides PET such as polylactic acid, thermoplastic starch-containing sustainable resins, other sustainable resins, bio-PE, bio-PP, and Bio-PET, viscose fibers, rayon fibers, or other suitable nonwoven fibers, for example. These fibers may have any suitable deniers or denier ranges and/or fiber lengths or fiber length ranges. In an instance where the plurality of first and second fibers are the same or substantially the same, the plurality of second fibers may be treated with a hydrophilic agent, such as a surfactant, to cause the plurality of second fibers to become hydrophilic or at least less hydrophobic. The plurality of first fibers may not be treated with the surfactant such that they remain in their natural hydrophobic state or the plurality of first fibers may be treated with a surfactant to become less hydrophobic.
The first layer may have a basis weight in the range of about 10 gsm to about 25 gsm. The second layer may have a basis weight in the range of about 10 gsm to about 45 gsm. The basis weight of the substrate (both first and second layers) may be in the range of about 20 gsm to about 70 gsm, about 20 gsm to about 60 gsm, about 25 gsm to about 50 gsm, about 30 gsm to about 40 gsm, about 30 gsm, about 35 gsm, or about 40 gsm, for example.
In a form, the basis weight of the substrate may be about 30 gsm to about 40 gsm or about 35 gsm. In such an example, the first layer may have a basis weight in the range of about 10 gsm to about 20 gsm, or about 15 gsm, and the second layer may have a basis weight in the range of about 15 gsm to about 25 gsm, or about 20 gsm. In another example, the basis weight of the substrate may be about 20 gsm. In such an example, the first layer may have a basis weight of about 10 gsm and the second layer may have a basis weight of about 10 gsm. In still another example, the basis weight of the substrate may be about 60 gsm. In such an example, the first layer may have a basis weight of about 24 gsm, and the second layer may have a basis weight of 36 gsm. All other suitable basis weight ranges for the first and second layers and the substrates are within the scope of the present disclosure. Accordingly, the basis weight of the layers and the substrates may be designed for specific product requirements.
Specifically recited herein are all 0.1 gsm increments within the above-specified ranges of basis weight and all ranges formed therein or thereby.
In some instances, it may be desirable to have a higher basis weight in the first layer compared to the second layer. For instance, the first layer's basis weight may be at least about 1 to about 4 times, at least about 1 to about 3.5 times, about 1.5 to about 3 times, about 1.5 times to about 3 times, about 2 times, about 2.5 times, or about 3 times greater than the second layer's basis weight. In some instances, the basis weight of the first layer may be in the range of about 20 gsm to about 30 gsm, and the basis weight of the second layer may be in the range of about 10 gsm to about 20 gsm, for example. Specifically recited herein are all 0.1 gsm increments within the above-specified ranges of basis weight and all ranges formed therein or thereby. By providing the first layer (hydrophobic) with a higher basis weight than the second layer (hydrophilic), more hydrophobic material than hydrophilic material is provided in the liquid permeable substrate. Upon information and belief, more hydrophobic material and less hydrophilic material in the liquid permeable substrate provides for better acquisition and/or dryness. The surface tension of the hydrophilic layer may be reduced to at least inhibit the hydrophilic layer (second layer) from contaminating the hydrophobic layer (first layer) (and making it more hydrophilic) upon the liquid permeable substrate receiving one or more gushes.
The liquid permeable substrates of the present disclosure may also form a portion of, or all of, the outer cover 23 which is joined to at least a portion of the backsheet 25. In other instances, the outer cover 23 may comprise a pattern (e.g., embossed pattern, printed pattern) and/or three-dimensional structure that is the same as, or similar in appearance to, the liquid permeable substrates of the present disclosure. In general, the appearance of at least a portion of a liquid permeable substrate on the wearer-facing surface may match, or substantially match, at least a portion of the outer cover 23 or another portion of absorbent article.
Referring generally to
The land areas 412 may be positioned intermediate: (1) adjacent projections 416, (2) adjacent recesses 414 and/or adjacent apertures 422. The land areas 412 may also surround at least a portion of, or all of, a majority of, or all of, the recesses 414 and/or the apertures and at least a majority of, or all of, the projections 416. The land areas 412 may be positioned between a plane of a perimeter of at least a majority of the apertures 422 and a plane of at least a majority of the top peaks 425 of the projections 416.
The projections 416 may alternate with the recesses 414 and/or the apertures 422 in a direction generally parallel with a lateral axis 424 of the liquid permeable substrate 400. The lateral axis 424 is generally parallel with the lateral axis 410 illustrated in
Two or more adjacent projections 416 may be separated from each other by a recess 414 and/or an aperture 422 and one or more land areas 412 in a direction generally parallel to the lateral axis 424 or in a direction generally parallel to the longitudinal axis 426. Two or more adjacent recesses 414 and/or apertures 422 may be separated by a projection 416 and one or more land areas 412 in a direction generally parallel to the lateral axis 424 or in a direction generally parallel to the longitudinal axis 426. The land areas 412 may fully surround the apertures 422 and the projections 416. The land areas 412 may together form a generally continuous grid through the substrate 400, while the projections 416 and the recesses 414 and/or the apertures 422 may be discrete elements throughout the substrate.
In some instances, two or more, such as four projections 416 may be positioned around at least a majority of, substantially all of, or all of, the recesses 414 and/or the apertures 422 (this does not include the land areas 412 intermediate the projections 416 and the recesses 414 and/or the apertures 422). Two or more recesses 414 and/or apertures 422, such as four, may be positioned around at least a majority of, substantially all of, or all of, the projections 416 (this does not include the land areas 412 intermediate the recesses 414 and/or the apertures 422 and the projections 416). The projections 416, recesses 414, apertures 422, and land areas 412 may all be formed of portions of the first and second layers of the substrate. If more than two layers are provided in a substrate, the projections 416, recesses 414, apertures 422, and land areas 412 may all be formed of portions of the first, second and third layers of the substrate. The same may be true if more than three layers are provided in a particular substrate. In other instances, the land areas 412 may only be formed in the first layer.
The apertures 422 and/or the recesses 414 may comprise a first set of apertures and/or recesses 414 together forming a first line in the substrate 400 and a second set of apertures 422 and/or recesses 414 together forming a second line in the substrate 400. The first line may be generally parallel with or generally perpendicular to the second line. The first line may also form an acute or obtuse angle with the second line. The projections 416 may comprise a first set of projections 416 together forming a first line in the substrate 400 and a second set of projections 416 together forming a second line in the substrate 400. The first line may be generally parallel with or generally perpendicular to the second line. The first line may also form an acute or obtuse angle with the second line.
The substrate 400 may be generally symmetrical about the lateral axis 424 and/or generally symmetrical about the longitudinal axis 426. In other instances, the substrate may not be symmetrical about the lateral axis 424 and/or the longitudinal axis 426.
In one form, the substrate 400 may comprise a first line comprising alternating apertures 422 and projections 416 extending in a direction parallel to the lateral axis 424 and a second adjacent line comprising alternating apertures 422 and projections 416 extending in the direction generally parallel to the lateral axis 424. The lines will run through the center of the apertures 422 and the projections 416. See for, example,
Parameters of the Three-Dimensional Substrates
All or a majority of the projections 416 may have a z-directional height in the range of about 300 μm to about 6000 μm, about 500 μm to about 5000 μm, about 500 μm to about 4000 μm, about 300 μm to about 3000 μm, about 500 μm to about 3000 μm, about 500 μm to about 2000 μm, about 750 μm to about 1500 μm, about 800 μm to about 1400 μm, about 900 μm to about 1300 μm, about 1000 μm to about 1300 μm, about 1100 μm to about 1200 μm, about 1165, about 1166, about 1167, or about 1150 μm to about 1200 μm, specifically reciting all 1 μm increments within the above-specified ranges and all ranges formed therein or thereby. The z-directional height of the projections 416 are measured according to the Projection Height Test described herein.
All or a majority of the recesses 414 may have a z-directional height in the range of about 200 μm to about 3000 μm, about 300 μm to about 2000 μm, about 100 μm to about 2000 μm, about 500 μm to about 2000 μm, about 500 μm to about 1500 μm, about 700 μm to about 1300 μm, about 800 μm to about 1200 μm, about 900 μm to about 1100 μm, about 900 μm to about 1000 μm, about 970 μm, or about 950 μm to about 1000 μm, specifically reciting all 1 μm increments within the above-specified ranges and all ranges formed therein or thereby. The z-directional height of the recesses 416 are measured according to the Recess Height Test described herein.
The substrate, 400, or portions thereof, may have an overall z-directional height in the range of about 500 μm to about 6000 μm, about 750 μm to about 4000 μm, about 1000 μm to about 6000 μm, about 1500 μm to about 6000 μm, about 1000 μm to about 3000 μm, about 1500 μm to about 2500 μm, about 1750 μm to about 2300 μm, about 1900 μm to about 2300 μm, about 2000 μm to about 2300 μm, about 2100 μm to about 2250 μm, about 2136 μm, or about 2135 μm, specifically reciting all 1 μm increments within the above-specified ranges and all ranges formed therein or thereby. The overall z-directional height of the substrate 400, or portions thereof, is measured according to the Overall Substrate Height Test described herein.
A majority of, or all of, the apertures 422 may have an effective aperture area in the range of about 0.4 mm2 to about 10 mm2, about 0.5 mm2 to about 8 mm2, about 0.5 mm2 to about 3 mm2, about 0.5 mm2 to about 4 mm2, about 0.5 mm2 to about 5 mm2, about 0.7 mm2 to about 6 mm2, about 0.7 mm2 to about 3 mm2, about 0.8 mm2 to about 2 mm2, about 0.9 mm2 to about 1.4 mm2, about 1 mm2, about 1.1 mm2, about 1.2 mm2, about 1.23 mm2, about 1.3 mm2, or about 1.4 mm2, specifically reciting all 0.1 mm2 increments within the above-specified ranges and all ranges formed therein or thereby. The effective aperture area of the apertures is measured according to the Aperture Test described herein.
A majority of, or all of, the apertures 422 may have a feret (length of aperture) in the range of about 0.5 mm to about 4 mm, about 0.8 mm to about 3 mm, about 1 mm to about 2 mm, about 1.2 mm to about 1.8 mm, about 1.4 mm to about 1.6 mm, about 1.49, or about 1.5 mm specifically reciting all 0.1 mm increments within the above-specified ranges and all ranges formed therein or thereby. The aperture feret is measured according to the Aperture Test described herein.
A majority of, or all of, the apertures 422 may have a minimum feret (width of aperture) in the range of about 0.5 mm to about 4 mm, about 0.7 mm to about 3 mm, about 0.8 mm to about 2 mm, about 0.9 mm to about 1.3 mm, about 1 mm to about 1.2 mm, about 1 mm, about 1.1 mm, about 1.11 mm, about 1.2 mm, or about 1.3 mm, specifically reciting all 0.1 mm increments within the above-specified ranges and all ranges formed therein or thereby. The aperture minimum feret is measured according to the Aperture Test described herein.
A majority of, or all of, the apertures 422 may have a feret to minimum feret ratio in the range of about 0.3 to about 2.5, about 0.5 to about 2, about 0.8 to about 1.6, about 1 to about 1.5, about 1.1 to about 1.5, about 1.2, about 1.3, about 1.35, about 1.4, or about 1.5, specifically reciting all 0.1 increments within the above-specified ranges and all ranges formed therein or thereby. The feret ratio is calculated by dividing the aperture feret by the aperture minimum feret.
The average lateral axis center-to-center aperture spacing of a majority of, or all of, adjacent apertures, measuring across a projection, is in the range of about 2 mm to about 20 mm, about 2 mm to about 15 mm, about 3 mm to about 12 mm, about 3 mm to about 10 mm, about 3 mm to about 8 mm, about 3 mm to about 7 mm, about 4 mm, about 5 mm, about 6 mm, about 7 mm, about 4 mm to about 6 mm, about 5 mm to about 6 mm, about 4.8 mm, about 4.9 mm, about 5.0 mm, about 5.1 mm, about 5.2 mm, about 5.3 mm, about 5.4 mm, about 5.5 mm, about 5.6 mm, about 5.7 mm, about 5.8 mm, or about 5.9 mm, specifically reciting all 0.1 mm increments within the above-specified ranges and all ranges formed therein or thereby. The average lateral axis center-to-center spacing of adjacent apertures is measured according to the Average Aperture Spacing Test (Lateral Axis Aperture Spacing) described herein.
The average longitudinal axis center-to-center aperture spacing of a majority of, or all of, adjacent apertures, measuring across a projection, is in the range of about 2 mm to about 20 mm, about 2 mm to about 15 mm, about 3 mm to about 12 mm, about 3 mm to about 10 mm, about 3 mm to about 8 mm, about 3 mm to about 7 mm, about 4 mm, about 5 mm, about 6 mm, about 7 mm, about 4 mm to about 6 mm, about 5 mm to about 6 mm, about 4.8 mm, about 4.9 mm, about 5.0 mm, about 5.1 mm, about 5.2 mm, about 5.3 mm, about 5.4 mm, about 5.5 mm, about 5.6 mm, about 5.7 mm, about 5.8 mm, or about 5.9 mm, specifically reciting all 0.1 mm increments within the above-specified ranges and all ranges formed therein or thereby. The average longitudinal axis center-to-center spacing of adjacent apertures is measured according to the Average Aperture Spacing Test (Longitudinal Axis Aperture Spacing) described herein.
A majority of, or all of, the projections 416 may have a widest cross-sectional diameter, taken in a direction parallel to the lateral axis of the absorbent article, in the range of about 1, to about 15 mm, about 1 mm to about 10 mm, about 1 mm to about 8 mm, about 1 mm to about 6 mm, about 1.5 mm to about 6 mm, about 2 mm to about 5 mm, specifically reciting all 0.1 mm increments within the above-specified ranges and all ranges formed therein or thereby.
A majority of, or all of, the projections 416 may have a widest cross-sectional diameter, taken in a direction parallel to the longitudinal axis of the absorbent article, in the range of about 1 mm to about 15 mm, about 1 mm to about 10 mm, about 1 mm to about 8 mm, about 1 mm to about 6 mm, about 1.5 mm to about 6 mm, about 2 mm to about 5 mm, specifically reciting all 0.1 mm increments within the above-specified ranges and all ranges formed therein or thereby.
The substrates of the present disclosure may have a % effective open area in the range of about 1% to about 50%, about 1% to about 40%, about 3% to about 35%, about 5% to about 25%, about 5% to about 20%, about 6% to about 18%, about 5% to about 15%, about 5%, about 8%, about 9%, about 9.5%, about 10%, about 10.5%, about 11%, or about 12%, specifically reciting all 0.1% increments within the above-specified ranges and all ranges formed therein or thereby. The % effective open area of the substrates is measured according to the Aperture Test described herein.
The substrates of the present disclosure may have apertures having a perimeter in the range of about 1 mm to about 50 mm, about 1 mm to about 30 mm, about 2 mm to about 20 mm, about 2 mm to about 15 mm, about 2 mm to about 10 mm, about 3 mm to about 8 mm, about 4 mm, about 5 mm, about 5.42 mm, about 6 mm, or about 7 mm, specifically reciting all 0.1 mm increments within the above-specified ranges and all ranges formed therein or thereby. The perimeter of the apertures is measured according to the Aperture Test described herein.
The first side 418 of the substrates 400 of the present disclosure may have geometric roughness value in the range of about 2 to about 4.5, about 2.5 to about 4, about 3 to about 4, about 3.1 to about 3.5, about 3.2, about 3.3, about 3.31, about 3.35, about 3.4, or about 3.5, specifically reciting all 0.1 increments within the above-specified ranges and all ranges formed therein or thereby. The geometric roughness values of the first side 418 of the substrates 400 of the present disclosure are measured according to the Descriptive Analysis Roughness Test described herein. The first side 418 of the substrates 400 of the present disclosure may have a coefficient of friction value in the range of about 0.2 to about 0.4, about 0.25 to about 0.35, about 0.27 to about 0.31, about 0.27, about 0.28, about 0.29, about 0.30, or about 0.31, specifically reciting all 0.01 increments within the above-specified ranges and all ranges formed therein or thereby. The coefficient of friction values of the first side 418 of the substrates 400 of the present disclosure are measured according to the Descriptive Analysis Roughness Test described herein. The first side 418 of the substrates 400 of the present disclosure may have a slip stick value in the range of about 0.010 to about 0.025, about 0.015 to about 0.020, about 0.015, about 0.016, about 0.017, about 0.018, or about 0.019, specifically reciting all 0.001 increments within the above-specified ranges and all ranges formed therein or thereby. The coefficient of friction values of the first side 418 of the substrates 400 of the present disclosure are measured according to the Descriptive Analysis Roughness Test described herein.
The second side 420 of the substrates 400 of the present disclosure may have geometric roughness value in the range of about 2 to about 4.0, about 2.3 to about 3.5, about 2.5 to about 3.3, about 2.6 to about 3.1, about 2.6, about 2.7, about 2.8, about 2.83, about 2.9, or about 3.0, specifically reciting all 0.1 increments within the above-specified ranges and all ranges formed therein or thereby. The geometric roughness values of the second side 420 of the substrates 400 of the present disclosure are measured according to the Descriptive Analysis Roughness Test described herein. The second side 420 of the substrates 400 of the present disclosure may have a coefficient of friction value in the range of about 0.2 to about 0.4, about 0.25 to about 0.35, about 0.27 to about 0.31, about 0.27, about 0.28, about 0.29, about 0.30, or about 0.31, specifically reciting all 0.01 increments within the above-specified ranges and all ranges formed therein or thereby. The coefficient of friction values of the second side 420 of the substrates 400 of the present disclosure are measured according to the Descriptive Analysis Roughness Test described herein. The second side 420 of the substrates 400 of the present disclosure may have a slip stick value in the range of about 0.010 to about 0.025, about 0.011 to about 0.018, about 0.012, about 0.013, about 0.014, about 0.015, or about 0.016, specifically reciting all 0.001 increments within the above-specified ranges and all ranges formed therein or thereby. The coefficient of friction values of the second side 420 of the substrates 400 of the present disclosure are measured according to the Descriptive Analysis Roughness Test described herein.
Ratios The ratio of the height of the projections (μm) to the % effective open area may be in the range of about 70 to about 160, about 80 to about 150, about 100 to about 145, about 95 to about 150, about 100 to about 140, about 110 to about 130, about 115 to about 130, about 118 to about 125, about 120, about 121, about 122, about 122.74, about 123, or about 124, specifically reciting all 0.1 increments within the specified ranges and all ranges formed therein or thereby.
The ratio of the overall substrate height (μm) to the % effective open area may be in the range of about 125 to about 350, about 150 to about 300, about 175 to about 275, about 200 to about 250, about 215 to about 235, about 220 to about 230, or about 225, specifically reciting all 0.1 increments within the specified ranges and all ranges formed therein or thereby.
The ratio of the height of the projections (μm) to the geometric roughness of a surface (e.g., first or second; 418 or 420) of the three-dimensional substrates may be in the range of about 250 to about 600, about 300 to about 500, about 325 to about 450, about 325 to about 425, about 350, about 352, about 410, or about 412, specifically reciting all 0.1 increments within the specified ranges and all ranges formed therein or thereby.
The ratio of the overall substrate height (μm) to the geometric roughness of a surface (e.g., first or second; 418 or 420) of the three-dimensional substrates may be in the range of about 500 to about 900, about 600 to about 800, about 645, about 650, about 700, about 750 m, or about 755, specifically reciting all 0.1 increments within the specified ranges and all ranges formed therein or thereby.
The substrates of the present disclosure may comprise one or more colors, dyes, inks, indicias, patterns, embossments, and/or graphics. The colors, dyes, inks, indicias, patterns, and/or graphics may aid the aesthetic appearance of the substrates.
The substrates of the present disclosure may be used as a portion of, or all of, any suitable products, such as dusters, wipes (wet or dry), makeup removal substrates, paper towels, toilet tissue, facial tissue, medical gowns, surgical substrates, wraps, filtration substrates, or any other suitable products.
The topsheet laminates of the present invention may comprise hot melt adhesive material, used to bond various substrates. The hot melt adhesives may be made with substantially less than 40 wt. %, less than 20 wt. % or be substantially free of an effective amount of a conventional tackifier material that can add any aspect of open time, substrate wetting or tack to the adhesive material, ie., be substantially tackifier-free. Common hot melt adhesives are made by combining polymer and additive components in a substantially uniform thermoplastic blend.
In some embodiments, the adhesive composition may comprise a first amorphous polymer and a second heterophase polymer. The amorphous polymer comprises an amorphous or random polymer comprising an alpha olefin co-polymer comprising major proportion of propene. The second polymer comprises a heterophase alpha olefin-co-polymer having amorphous character and at least some substantial crystalline content. The crystalline content can be in the form of one or more polymer blocks or sequences that are stereoregular. In one embodiment, these sequences or blocks are substantially crystallizable sequences or blocks. The adhesive material may comprise a first polymer comprising a polyolefin comprising a substantially amorphous or randomly polymerized polymer material and a second polymer comprising a heterophase polymer.
In some embodiments, the adhesive material may comprise a first polymer comprising a polyolefin copolymer comprising a substantially amorphous or randomly polymerized polymer material comprising 1-butene and a second amorphous polymer comprising a compatible amorphous liquid butene polymer such as a polyisobutylene polymer or similar material. The polyisobutylene polymer may comprise a substantial proportion (greater than 50 mole % and often greater than 90 mole %) of an isobutylene monomer.
The first amorphous polymer may comprise typically butene (e.g.) 1-butene, and can be a copolymer or terpolymer that can contain ethylene, propene or a second C4-40 olefin polymer. These substantially amorphous low crystallinity polymers have less than 10% and preferably less than 5% crystalline character.
The second heterophase olefin polymer comprises a first poly alpha olefin polymer comprising a substantial proportion (greater than 40 or 50 mole %) of a propene monomer and comprises an amorphous polymer with some crystalline content.
The amorphous polymer is a butene-based copolymer (the minimum amount is at least about 30 or 40 or 50 or 60 wt. % of 1-butene), which may also be referred to as a random butene-α-olefin copolymer. The butene copolymer includes one or more units, i.e., monomer units, derived from propene, one or more comonomer units derived from ethylene or α-olefins including from 4 to about 20 carbon atoms.
The first copolymer comprises about 30 mole %-about 75 mole %, preferably about 40 mole % to about 70 mole %, about 50 mole %-about 65 mole %, of units derived from butene. In addition to butene-derived units, the present copolymer contains from about 70 mole %-about 30 mole % to about 60 mole %-about 40 mole %, of units derived from preferably ethylene, propene or at least one C5 to 10 alpha-olefin monomer.
In one or more embodiments, the alpha-olefin comonomer units can also be derived from other monomers such as ethylene, 1-butene, 1-hexane, 4-methyl-1-pentene and/or 1-octene.
Exemplary alpha-olefins are selected from the group consisting of ethylene, butene-1, pentene-1,2-methylpentene-1,3methylbutene-1, hexene-1,3-methylpentene-1,4-methylpentene-1,3,3-dimethylbutene-1, heptene-1, hexene-1, methylhexene-1, dimethylpentene-1, trimethylbutene-1, ethylpentene-1, octene-1, methylpentene-1, dimethylhexene-1, trimethylpentene-1, ethylhexene-1, methylethylpentene-1, diethylbutene-1, propylpentane-1, decene-1, methylnonene-1, nonene-1, dimethyloctene-1, trimethylheptene-1, ethyloctene-1, methylethylbutene-1, diethylhexene-1, dodecene-1, and hexadodecene-1.
In one or more embodiments, amorphous copolymer comprises about 30 mole %-about 75 mole %, preferably about 40 mole % to about 60 mole % of units derived from butene and from about 70 mole %-about 30 mole % to about 60 mole %-about 40 mole %, about 50 mole %-about 65 mole %, of units derived from at least one alpha-olefin monomer selected from ethylene, propene, 1-hexene or 1-octene. Small amounts of α-olefin monomer(s) can be used in the range of about 0.1 to 20 mole %. The amorphous polymer has a weight average molecular weight (Mw) of about 1,000 to about 25,000 or less, or about 2,000 to 20,000, or from about 5000 to about 45,000.
In one or more embodiments, first copolymer comprises about 30 mole %-about 70 mole %, or about 40 mole % to about 60 mole % of units derived from butene and from about 70 mole %-about 30 mole % to about 60 mole %-about 40 mole %, of units derived from propene, while small amounts of α-olefin monomer(s) can be used in the range of about 0.1 to 20 mole %.
The amorphous polymer may have a weight average molecular weight (Mw) of about 1,000 to about 50,000 or less, or about 5,000 to 45,000.
The amorphous copolymer may have a viscosity of less than 10,000 mPa·s (1 centipoise [cps]=1 mPa·s), for example about 2000 to 8000 mPa·s, when measured by ASTM D3236 at 190° C. Melt Viscosity was determined according to ASTM D-3236, which is also referred to herein as “viscosity” and/or “Brookfield viscosity”.
Some examples of amorphous polyolefin include the Rextac polymers made by Huntsman including Rextac E62, E-63, E-65, 2815, 2830, etc. See, for example Sustic, U.S. Pat. No. 5,723,546 for a description of the polymers and which is expressly incorporated herein. Other useful amorphous polymers are sold as Vestoplast® and Eastoflex® materials.
The adhesive material may comprise a second polyolefin comprising a substantially heterophase copolymer. The heterophase polyolefin may comprise a propene copolymer (i.e.) propene-based polymer with other comonomer(s). The propene-based polymer backbone preferably comprises propene and one or more C2 or C4-20 α-olefins. The propene-based heterophase polymer, for example, may comprise propene and ethylene, hexene or optionally other C2 or C4-20 α-olefins. The polymer comprises about 99.5 to about 70 wt. %, preferably about 95 to about 75 wt. % of units derived from propene. In addition to propene derived units, the present copolymer contains from about 0.1 to 30 wt. % preferably from about 5 to 25 wt. %, of units derived from preferably at least C2-4 or a C5-10 alpha-olefin.
In one or more embodiments, the second copolymer comprises a major proportion of propene and about 0.1 to 30 wt. %, or 2 to 25 wt. % ethylene. In one or more embodiments, the second copolymer comprises a major proportion of propene and about 0.1 to 30 wt. %, or 2 to 25 wt. % 1-butene.
In one or more embodiments, the second copolymer comprises a major proportion of propene and about 0.1 to 30 wt. %, or 2 to 25 wt. % 1-hexene. In one or more embodiments, the second copolymer comprises a major proportion of propene and about 0.1 to 30 wt. %, or 2 to 25 wt. % 1-octene.
Other comonomer for use in either the first or second polyolefin comprise ethylene or α-olefins containing 4 to 12 carbon atoms. Exemplary α-olefins may be selected from the group consisting of ethylene; 1-butene; 1-pentene; 2-methyl-1-pentene; 3-methyl-1-butene; 1-hexene-3-methyl-1-pentene-4-methyl-1-pentene-3,3-dimethyl-1-butene; 1-heptene; 1-hexene; 1-methyl-1-hexene; dimethyl-1-pentene; trimethyl-1-butene; ethyl-1-pentene; 1-octene; methyl-1-pentene; dimethyl-1-hexene; trimethyl-1-pentene; ethyl-1-hexene; 1-methylethyl-1-pentene; 1-diethyl-1-butene; propyl-1-pentene; 1-decene; methyl-1-nonene; 1-nonene; dimethyl-1-octene; trimethyl-1-heptene; ethyl-1-octene; methylethyl-1-butene; diethyl-1-hexene; 1-dodecene and 1-hexadodecene. Preferred C4-10 alpha-olefins are those having 6 to 8 carbon atoms, with the most preferred alpha-olefin being 1-hexene and 1-octene.
Preferred propene copolymers are copolymers wherein the comonomer is ethylene, 1-butene, 1-hexene or 1-octene. The stereo-regular (isotactic or syndiotactic) sequence or block content of the polymers imparts a heterophase (partial amorphous and partial crystalline) character of crystallizable content to the polymers. As used herein and as applied to semi-crystalline heterophase copolymers, the term “crystallizable” describes those polymer sequences or blocks that can crystallize upon cooling. Crystalline content of the solidified semicrystalline copolymers increases the cohesive strength of the hot melt adhesives. Hot melt adhesive formulations based on metallocene polymerized semicrystalline copolymers can eventually build sufficient crystalline content over time to achieve good cohesive strength in the formulation.
The second heterophase polymer comprises crystallizable polymer blocks or sequences, preferably of stereoregular sequences of polymerized monomer such as ethylene or propene, which sequences are long enough to crystallize, typically at least repeating or block monomer units per sequence.
In preferred embodiments, the crystallizable segments can be stereoregular or isotactic. Isotacticity of the olefin sequences can be achieved by polymerization with the choice of a desirable catalyst composition. The Isotacticity is conventionally measured using DSC or C-13 NMR instrumental techniques.
The heterophase polymer has a crystallinity of at least 5 wt. %, 10 wt. %, 20 wt. %, 40 wt. % or 50 wt. %, preferably between 20% and 80%, more preferably between 25% and 70%.
The heat of fusion of the heterophase copolymers (by ASTM E793) is about 10 J/g to about 70 J/g and about 15 J/g to about 70 J/g, with a melting point less than 150° C. and about 105° C. to about 135° C.
The heterophase polymer has a weight average molecular weight (Mw) of about 20,000 or less, preferably about 10,000 or less, preferably about 500 to 8,000.
The heterophase copolymer has a viscosity of less than 20,000 mPa·s (1 centipoise [cps]=1 mPa·s), for example less than 15000 mPa·s, in certain application less than 10,000 mPa·s and less than 5,000 mPa·s when measured at 190° C. using a Brookfield viscometer (as measured by ASTM D 3236) which is also referred to herein as “viscosity” and/or “Brookfield viscosity.”
Some examples of heterophase polymers useful in the hot melt adhesive compositions of include polyolefin such as polyethylene, polypropylene, and copolymers thereof such as polypropylene based elastomers sold by ExxonMobil Chemical of Houston, Tex. under the trade name VISTAMAXX™ and polyethylene based elastomers such as those sold by Dow Chemical Company of Midland, Mich. under the trade names AFFINITY™ and ENGAGE™.
Other heterophase polymers that are useful in the hot melt adhesive compositions include the polyolefin elastomers VISTAMAXX™ 8816, VISTAMAXX™ 2230, and ENGAGE™ 8200.
AFFINITY™ GA 1900 has a density of 0.870 g/cm3 according to ASTM D792, heat of fusion of 46.1 J/g, and a Brookfield viscosity of 8200 cP at 177° C. according to ASTM D 1084. AFFINITY™ GA 1950 has a density of 0.874 g/cm3 according to ASTM D792, heat of fusion of 53.4 J/g, and a
Brookfield viscosity of 17,000 cP at 177° C. according to ASTM D 1084. ENGAGE™ 8200 has a density of 0.87 g/cm3 according to ASTM D792 and a melt index of 5 g/10 min at 190° C. These olefin elastomers are compatible with the propylene copolymers useful in the hot melt adhesive compositions and improve physical properties such as low temperature adhesive performance without sacrificing effective set time.
Any conventional polymerization synthesis processes may prepare the polyolefin copolymers. Preferably, one or more catalysts, which are typically metallocene catalysts or Zeigler-Natta, catalysts, are used for polymerization of an olefin monomer or monomer mixture. Polymerization methods include high pressure, slurry, gas, bulk, suspension, supercritical, or solution phase, or a combination thereof, preferably using a single-site metallocene catalyst system. The catalysts can be in the form of a homogeneous solution, supported, or a combination thereof. Polymerization may be carried out by a continuous, a semi-continuous or batch process and may include use of chain transfer agents, scavengers, or other such additives as deemed applicable. By continuous is meant a system that operates (or is intended to operate) without interruption or cessation. For example a continuous process to produce a polymer would be one where the reactants are continually introduced into one or more reactors and polymer product is continually withdrawn. In one embodiment, the propene copolymer described herein is produced in a single or multiple polymerization zones using a single polymerization catalyst. The heterophase polymers are typically made using multiple metallocene catalyst blends that obtain desired heterophase structure.
In some embodiments, the adhesive may comprise an amorphous polyolefin copolymer composition comprising more than 40 mole % 1-butene and a second amorphous polymer comprising at least one butene monomer, wherein the polymer is compatible with the polyolefin. In some embodiments, the adhesive may consist essentially of an amorphous polyolefin copolymer composition comprising more than 40 mole % 1-butene and a compatible second amorphous polymer comprising at least one butene monomer. The second polymer compatible with the polyolefin may have a molecular weight (MWn) of at least 1000. Such compatibility arises from a liquid amorphous material comprising at least one butene monomer (1-butene, cis and trans-2-butene, and isobutylene) isomer. Unlike conventional plasticizing oils such as white oils having a conventional hydrocarbon character, useful materials are sufficiently compatible and as a result improve add-on processability characteristics, reduce viscosity, and maintain adhesive bond while improving cohesive properties. The term “compatible or compatibility” of a blend of polymers, as the term is used in this disclosure, means that (1) the materials blend into a uniform hot melt and (2) the cohesive strength of a mixture (70/30 to 50/50) by weight of the amorphous 1-butene polymer and the second amorphous polymer is maintained for construction purposes. Preferred materials comprise a compatible extender, diluents, and viscosity modifier such as a polyisobutylene polymer. The polymer can comprise major proportion of isobutylene units or can be represented as:
[—C(CH3)2—CH2—]n;
wherein n=15 to 75. Preferred materials such as a polyisobutylene are viscous liquids with molecular weight of about 200-20,000, about 200-5,000 or about 500-3,000. The preferred liquid materials have a Saybolt Universal seconds (SUS) viscosity at 100° C. of about 100 to 20,000. The characteristic features of polyisobutylene are low gas permeability and high resistance to the action of acids, alkalis, and solutions of salts, as well as high dielectric indexes. They degrade gradually under the action of sunlight and ultraviolet rays (the addition of carbon black slows this process). In industry, polyisobutylene is produced by ionic (AlCl3 catalyzed) polymerization of the monomer at temperatures from −80° to −100° C.; they are processed using the ordinary equipment of the rubber industry. Polyisobutylene combines easily with natural or synthetic rubbers, polyethylene, polyvinyl chloride, and phenol-formaldehyde resins.
Any of the compositions disclosed herein can also comprise a plasticizer or plasticizing oil or extender oil that may reduce viscosity or improve tack properties in the adhesive. Any plasticizer known to a person of ordinary skill in the art may be used in the adhesion compositions disclosed herein. Nonlimiting examples of plasticizers include olefin oligomers, low molecular weight polyolefin such as liquid polybutene, low molecular weight non-aromatic polymers (e.g. REGALREZ 101 from Eastman Chemical Company), phthalates, mineral oils such as naphthenic, paraffinic, or hydrogenated (white) oils (e.g. Kaydol oil or ParaLux oils (Chevron U.S.A. Inc.)), vegetable and animal oil and their derivatives, petroleum derived oils, and combinations thereof. Low molecular weight polyolefin may include those with Mw as low as 100, in particular, those in the range of from about 100 to 3000, in the range of from about 250 to about 2000 and in the range of from about 300 to about 1000.
In some embodiments, the plasticizers include polypropylene, polybutene, hydrogenated polyisoprene, hydrogenated polybutadiene, polypiperylene, copolymers of piperylene and isoprene, and the like, having average molecular weights between about 350 and about 10,000. In other embodiments, the plasticizers include glyceryl esters of the usual fatty acids and polymerization products thereof a polymer of isobutylene.
As noted above, embodiments of preferred compositions are made with substantially less than 40 wt. %, less than 20 wt. % or are substantially free of an effective amount of a conventional tackifier material that can add any aspect of open time, substrate wetting or tack to the adhesive material. Avoiding the use of a tackifier reduces adhesive density, adhesive and product costs, and frees formulators from the use of materials in short supply. Further, tackifier can impart undesirable odor in disposable articles and can also act as carriers of low molecular weight plasticizers (like process oils that are used in SBC based adhesives) that can weaken the polyethylene film materials used in baby diapers. For example, back sheet integrity is becoming more important due to the downsizing of the polyethylene film thickness used in these articles. By the term “conventional tackifier resins”, those resins commonly available in the adhesive art and industry that are used in typical hot melt adhesives. Examples of conventional tackifing resins included in this range include an aliphatic hydrocarbon resins, aromatic modified aliphatic hydrocarbon resins, hydrogenated poly-cyclopentadiene resins, poly-cyclopentadiene resins, gum rosins, gum rosin esters, wood rosins, wood rosin esters, tall oil rosins, tall oil rosin esters, poly-terpene, aromatic modified poly-terpene, terpene-phenolic, aromatic modified hydrogenated poly-cyclopentadiene resins, hydrogenated aliphatic resins, hydrogenated aliphatic aromatic resins, hydrogenated terpene and modified terpene and hydrogenated rosin esters. Often in conventional formulations such resins are used in amounts that range from about 5 to about 65 wt. %, often about 20 to 30 wt. %.
In further embodiments, the compositions disclosed herein optionally can comprise an antioxidant or a stabilizer. Any antioxidant known to a person of ordinary skill in the art may be used in the adhesion composition disclosed herein. Non-limiting examples of suitable antioxidants include amine-based antioxidants such as alkyl diphenyl amines, phenyl-naphthylamine, alkyl or aralkyl substituted phenyl-naphthylamine, alkylated p-phenylene diamines, tetramethyl-diaminodiphenylamine and the like; and hindered phenol compounds such as 2,6-di-t-butyl-4-methylphenol; 1,3,5-trimethyl-2,4,6-tris(3′,5′-di-t-butyl-4′-hydroxybenzyl)benzene; tetra kis[(methylene(3,5-di-t-butyl-4-hydroxyhydrocinnamate)]methane (e.g., IRGANOX™1010, from Ciba Geigy, New York); octadecyl-3,5-di-t-butyl-4-hydroxycinnamate (e.g., IRGANOX™ 1076, commercially available from Ciba Geigy) and combinations thereof. Where used, the amount of the antioxidant in the composition can be from about greater than 0 to about 1 wt. %, from about 0.05 to about 0.75 wt. %, or from about 0.1 to about 0.5 wt. % of the total weight of the composition.
In further embodiments, the compositions disclosed herein optionally can comprise an UV stabilizer that may prevent or reduce the degradation of the composition by radiation. Any UV stabilizer known to a person of ordinary skill in the art may be used in the adhesion composition disclosed herein. Non-limiting examples of suitable UV stabilizers include benzophenones, benzotriazoles, aryl esters, oxanilides, acrylic esters, formamidine carbon black, hindered amines, nickel quenchers, hindered amines, phenolic antioxidants, metallic salts, zinc compounds and combinations thereof. Where used, the amount of the UV stabilizer in the composition can be from about greater than 0 to about 1 wt. %, from about 0.05 to about 0.75 wt. %, or from about 0.1 to about 0.5 wt. % of the total weight of the composition.
In further embodiments, the compositions disclosed herein optionally can comprise a brightener, colorant or pigment. Any colorant or pigment known to a person of ordinary skill in the art may be used in the adhesion composition disclosed herein. Non-limiting examples of suitable brighteners, colorants or pigments include fluorescent materials and pigments such as triazine-stilbene, coumarin, imidazole, diazole, titanium dioxide and carbon black, phthalocyanine pigments, and other organic pigments such as IRGAZINB, CROMOPHTALB, MONASTRALB, CINQUASIAB, IRGALITEB, ORASOLB, all of which are available from Ciba Specialty Chemicals, Tarrytown, N.Y. Where used, the amount of the brightener, colorant or pigment in the composition can be from about greater than 0 to about 10 wt %, from about 0.01 to about 5 wt %, or from about 0.1 to about 2 wt % of the total weight of the composition.
The compositions disclosed herein may also optionally comprise a fragrance such as a perfume or other odorant. Such fragrances may be retained by a liner or contained in release agents such as microcapsules that may, for example, release fragrance upon removal of a release liner from or compression on the composition.
In further embodiments, the compositions disclosed herein optionally can comprise filler. Any filler known to a person of ordinary skill in the art may be used in the adhesion composition disclosed herein. Non-limiting examples of suitable fillers include sand, talc, dolomite, calcium carbonate, clay, silica, mica, wollastonite, feldspar, aluminum silicate, alumina, hydrated alumina, glass bead, glass microsphere, ceramic microsphere, thermoplastic microsphere, barite, wood flour, and combinations thereof. Where used, the amount of the filler in the composition can be from about greater than 0 to about 60 wt. %, from about 1 to about 50 wt. %, or from about 5 to about 40 wt. %
One substantial advantage in the claimed adhesives relates to a density of the adhesive formulations. Conventional tackifier is at a density that often ranges from about 1.07-1.09 g-cm−3. Conventional formulated adhesives containing a conventional tackifier in amounts of about 40 to 60 wt. %, have a density greater than 0.9 g-cm−3 or more. The formulated adhesives of the invention, substantially free of tackifier, have densities less than 0.9 g-cm−3, often in the range about 0.85-0.89 g-cm−3 often 0.86-0.87 g-cm−3. Not only are these adhesives free of the problems arising from tackifier materials, but the use of the claimed adhesives, and a lower density, permits the use of a reduced amount when measured by weight, resulting in cost savings.
Another aspect is methods of manufacture employing the hot melt adhesive compositions. The method involves application of the molten compositions to a substrate, followed by contact of the adhesive composition with a second substrate within 0.1 second to 5 seconds after application of the adhesive composition to the first substrate, wherein the contacting results in an adhesive bond between the substrates.
The hot melt adhesive compositions have melt rheology and thermal stability suitable for use with conventional hot melt adhesive application equipment. The blended components of the hot melt adhesive compositions have low melt viscosity at the application temperature, thereby facilitating flow of the compositions through a coating apparatus, e.g., coating die or nozzle, without resorting to the inclusion of solvents or extender oil into the composition. Melt viscosities of the hot melt adhesive compositions are between 1500 cP and 3500 cP or about 2000 cP to 3000 cP in mille Pascal-seconds or centipoise (cP) using a Brookfield thermosel RVT viscometer using a rotor number 27 at 176.66° C. (50 rpm, 350° F.). The hot melt adhesive compositions have a softening point (ASTM D 3461-97 Standard Test Method for Mettler Softening Point Method) of about 80° C. to 140° C., in some embodiments about 115° C. to 130° C. For certain applications, the hot melt adhesive compositions have effective set times of about 5 seconds or less, for example about 0.1 second to 5 seconds, in embodiments about 0.1 second to 3 seconds, and in some embodiments about 0.2 second to 1 second. The effective set time of the hot melt adhesives are unexpectedly short, particularly given that the open time remains in the acceptable range.
The adhesives described herein may be used to bond any topsheet layer to an adjacent substrate, or to create any adhesively bonded laminate in the absorbent article.
The adhesive is typically applied in an amount of about 1 to about 100 or about 4 to about 90 or about 7 to about 70 grams per square meter (g/m2) of resulting bonded material. The material may be applied in an amount of about 0.1 to about 20 or about 0.2 to about 10 or about 0.3 to about 15 grams per square meter (g/m2) of resulting bonded material. The adhesive material can be used at an add-on rate of 0.5 to 2 g/m2, 0.6 to 1.7 g/m2 or 0.7 to 1.5 g/m2, for absorbent articles.
A number of hot melt adhesive compositions were prepared by blending first amorphous copolymer, second heterophase copolymer, polymer plasticizer/diluent and antioxidant under mixing conditions at elevated temperatures to form a fully homogenized fluid melt. Mixing temperatures varied from about 135 to about 200° C. preferably about 150 to about 175° C. A WiseStir® mixer was used to ensure full homogenization of components into a final adhesive composition.
Hot melt adhesive compositions were formulated by melt blending as described below, wherein specific components and amounts of the components are shown in the following table 3.
These data indicates that the materials will provide excellent bonding in disposable absorbent articles. Note viscosity relates to the resistance to flow of the material under certain conditions. This distinctive property determines the flowability, degree of wetting, and penetration of the substrate by the molten polymer. It provides an indication of its processability and utility as a hot melt adhesive material. Melt viscosity is generally directly related to a polymer molecular weight and is reported in Millipascal-second's or centipoise (cP) using a Brookfield thermosel RVT viscometer using a rotor number 27 at the stated temperature.
Mettler softening point in degrees Centigrade or degrees Fahrenheit is typically measured using ASTM D3104. The amorphous nature of the poly olefin materials results in a melting point, which is not sharp or definite. Rather as the temperature increases, amorphous polymers gradually change from a solid to a soft and then to a liquid material. No clearly defined glass transition or melting temperature is often noted. This temperature testament that generally measures the precise temperature at which a disc of polymer sample, heated at a rate of 2° C. per minute or 10° per minute becomes soft enough to allow the test object, a steel ball (grams) drops through the sample. The softening point of a polymer reported in degrees Centigrade or degrees Fahrenheit is important because it typically indicates the polymer's heat resistance, useful application temperatures and solidification points.
A number of hot melt adhesive compositions were prepared by blending first amorphous copolymer, second compatible copolymer and antioxidant under mixing conditions at elevated temperatures to form a fully homogenized melt. Mixing temperatures varied from about 135 to about 200° C. preferably about 150 to about 175° C. as needed to obtain uniformity. A traditional heated stirred blade (WiseStir®) mixer was used to ensure full homogenization in a heated container into a final adhesive composition.
Hot melt adhesive compositions were formulated by melt blending, as described below, wherein specific components and amounts of the components are shown in the following table 5.
Hot melt adhesive compositions are formulated by melt blending, as described below, wherein specific components and amounts of the components are shown in the following table 6. Comparative examples 1 and 2 each form a non-uniform composition that has insufficient cohesive/adhesive strength to be usefully measured.
All tests show adhesion and good bonding. The data from runs 2, 3, 4, 5, 9, 12, 15, 16, 17, 19, and 20 show values that all exceeded requirements for a successful construction adhesive for absorbent articles.
These data indicates that the materials will provide excellent bonding in disposable absorbent articles. Note viscosity relates to the resistance to flow of the material under certain conditions. This distinctive property determines the flowability, degree of wetting, and penetration of the substrate by the molten polymer. It provides an indication of its processability and utility as a hot melt adhesive material.
Melt viscosity is generally directly related to a polymer molecular weight and is reported in millipascal-second (mP·s) or centipoise (cP) using a Brookfield DV-II+Pro (Rotation 10 rpm-Spindle # SC4-27) at the stated temperature.
Mettler softening point in degrees Centigrade or degrees Fahrenheit is typically measured using ASTM D3104. The amorphous nature of the polyolefin materials results in a melting point, which is not sharp or definite. Rather as the temperature increases, amorphous polymers gradually change from a solid to a soft and then to a liquid material. No clearly defined glass transition or melting temperature is often noted. This temperature testament that generally measures the precise temperature at which a disc of polymer sample, heated at a rate of 2° C. per minute or 10° F. per minute becomes soft enough to allow the test object, a steel ball (grams) drops through the sample. The softening point of a polymer reported in degrees Centigrade or degrees Fahrenheit is important because it typically indicates the polymer's heat resistance, useful application temperatures and solidification points.
Peel test values were obtained by forming a laminate from a SMS non-woven (11.6 g/m2) micro-porous polyethylene film (0.5 mil/0.127 micron) using lamination conditions as shown in Table 4. The laminate is cut into 1 inch/25.4 mm wide strips in the cross machine direction. Peel force was measured by separating the laminate at room temperature using a TMax pull tester at a rate of 20 in/sec (50.8 cm/sec) with the peek force averaged over a 15 period.
The claims may suitably comprise, consist of, or consist essentially of, or be substantially free of any of the disclosed or recited elements. The invention illustratively disclosed herein can also be suitably practiced in the absence of any element which is not specifically disclosed herein.
The dimensions and values disclosed herein are not to be understood as being strictly limited to the exact numeral values recited. Instead, unless otherwise specified, each such dimension is intended to mean both the recited value and a functionally equivalent range surrounding that value. For example, a dimension disclosed as “40 mm” is intended to mean “about 40 mm”.
All documents cited in the Detailed Description of the Invention are, in relevant part, incorporated herein by reference; the citation of any document is not to be construed as an admission that it is prior art with respect to the present invention. To the extent that any meaning or definition of a term in this written document conflicts with any meaning or definition of the term in a document incorporated by reference, the meaning or definition assigned to the term in this written document shall govern.
While particular embodiments of the present invention have been illustrated and described, it would be obvious to those skilled in the art that various other changes and modifications can be made without departing from the spirit and scope of the invention. It is therefore intended to cover in the appended claims all such changes and modifications that are within the scope of this invention.
| Number | Date | Country | |
|---|---|---|---|
| 62267545 | Dec 2015 | US |
