Patent Application
20120165770
The present invention relates to absorbent articles that include a stimulation material. More specifically, the invention relates to an absorbent article, such as training pants, that provides the wearer with a noticeable sensation upon fluid contact.
Absorbent articles, for example, children's training pants, have been designed with a stimulation material such as temperature change particles to provide a temperature change sensation upon urination (a liquid insult). This is done in an attempt to enhance a child's recognition of when urination occurs. As can be appreciated, such recognition can be an important step in the toilet training process.
Currently, stimulation material in a particulate form has been incorporated into a coform material and cut into pledgets for placement in absorbent articles. Stimulation material is trapped within the coform structure. Bonding between the coform fibers and the stimulation material is poor so that when the coform web is cut into pledgets, the stimulation material falls away from the pledget edges, resulting in a waste of the stimulation material of about 25 to about 30 percent.
In addition to the waste of stimulation material, the coform structure cannot hold more than about 300 gsm of the stimulation material without a significant loss of stimulation material due to poor bonding. This means that the sensation cannot be enhanced by increasing the amount of the stimulation material.
To increase sensation and overcome the problem of stimulation material waste due to the poor bonding, a stimulation laminate was developed in which the stimulation material was adhesively bonded to substrates in such a manner that the stimulation material covered a substrate completely. Several layers of stimulation materials were disposed between several layers of substrate. The laminate structure greatly improved the bonding efficiency of the stimulation materials, so that maximum add-on levels of these materials could be increased from 300 gsm to about 1000 gsm. More than 99% of stimulation materials were captured in the laminate structure during lamination process. There was virtually no loss or waste of stimulation material either during use or when pledgets were cut from the web of stimulation laminate.
Though the adhesive bonding of the stimulation material worked well to prevent loss of stimulation material in manufacturing and converting process conditions, it was found that the stimulation material migrated by being washed away from the part of the pledget area subjected to a direct liquid insult. The migration of stimulation materials due to a direct insult to the pledget lowers stimulation efficiency. Often the stimulation material is displaced to areas of the absorbent article that do not have contact with the wearer's skin. Because of this displacement, it is observed that less than about 50% stimulation composite is available to deliver some sensation to wearer. To add stimulation material to the laminate to compensate for migration would dramatically increases manufacturing costs.
Thus, there is a need for a pledget containing a stimulation material, wherein the stimulation material can provide an improved level of noticeable sensation (e.g. cooling, warming, tingling, and/or pressure). In addition, there is a need for a pledget containing a stimulation material, wherein the stimulation material is focused in a predetermined region with respect to a “target zone” at which a liquid insult occurs. Moreover, there is a need for a stimulation composite which exhibits a negligible waste of stimulation material when the stimulation composite is converted into pledgets. Overall, there is a need for a pledget having all the advantages of the laminate structure described above, while containing a reduced amount of stimulation material.
In one aspect, an absorbent article is made from several components, one of which is a stimulation composite that is disposed between a top sheet and an absorbent core. The stimulation composite is made from a stimulation blend that includes a stimulation material that is partially bonded to pressure-sensitive adhesive fibers. The stimulation blend and some pressure-sensitive adhesive fibers are arranged into a predetermined pattern and sandwiched between a body-facing substrate and a garment-facing substrate to form a stimulation composite. The stimulation composite is disposed between a body-facing substrate and a garment-facing substrate.
The absorbent article is further constructed from a backsheet, an absorbent core, and a topsheet. The absorbent core is located between the topsheet and the backsheet, and the stimulation composite is located between the absorbent core and the topsheet.
In another aspect, a stimulation composite includes a stimulation blend made from a stimulation material that is mostly partially bonded to pressure-sensitive hot-melt adhesive fibers. The stimulation blend is disposed between a body-facing substrate and a garment-facing substrate.
In a further aspect, a method of making a stimulation composite includes but is not limited to the following steps. A garment-facing substrate is conveyed to a deposit system, whereby the deposit system includes a particle feeder; and a first adhesive applicator and a second adhesive applicator, each flanking the particle feeder at a predetermined angle. The first adhesive applicator is located upstream of the particle feeder, and the second adhesive applicator is located downstream of the particle feeder. The terms upstream and downstream are relative to the machine direction. A stimulation material is emitted from the particle feeder, and pressure-sensitive hot-melt adhesive fibers are emitted from the first and second adhesive applicators. To create a stimulation blend, the stimulation material and meltblown adhesive fibers are comingled. The stimulation blend is then disposed onto the garment-facing substrate. In another aspect, additional steps may include the disposing of a body-facing substrate onto the stimulation blend, and applying pressure to the resulting stimulation composite.
The patent or application file contains at least one drawing executed in color. Copies of this patent or patent application publication with color drawing(s) will be provided by the Office upon request and payment of the necessary fee.
While the specification concludes with claims particularly pointing out and distinctly claiming the subject matter that is regarded as the present invention, it is believed that the invention will be more fully understood from the following description taken in conjunction with the accompanying drawings. In the accompanying drawing figures, like reference numerals identify like elements, which may or may not be identical in the several exemplary embodiments that are depicted. Some of the figures may have been simplified by the omission of selected elements for the purpose of more clearly showing other elements. Such omissions of elements in some figures are not necessarily indicative of the presence or absence of particular elements in any of the exemplary embodiments, except as may be explicitly delineated in the corresponding written description. None of the drawings are necessarily to scale.
It should be noted that, when employed in the present disclosure, the terms “comprises,” “comprising” and other derivatives from the root term “comprise” are intended to be open-ended terms that specify the presence of any stated features, elements, integers, steps, or components, and are not intended to preclude the presence or addition of one or more other features, elements, integers, steps, components, or groups thereof.
The term “absorbent article” generally refers to devices which can absorb and contain fluids. For example, personal care absorbent articles refer to devices which are placed against or near the skin to absorb and contain the various fluids discharged from the body.
The term “bond” and its derivatives refer to the joining, adhering, connecting, attaching, sewing together, or the like, of two elements. Two elements will be considered to be bonded together when they are bonded directly to one another or indirectly to one another, such as when each is directly bonded to intermediate elements. Notwithstanding the foregoing, in the context of the present invention, all stimulation materials are bonded directly, without any intermediate elements, to the adhesives described herein.
The term “coform” refers to a blend of meltblown fibers and absorbent fibers such as cellulosic fibers that can be formed by air forming a meltblown polymer material while simultaneously blowing air-suspended fibers into the stream of meltblown fibers. The coform material may also include other materials, such as stimulation materials. The meltblown fibers and absorbent fibers are collected on a forming surface, such as provided by a foraminous belt.
The forming surface may include a gas-pervious material that has been placed onto the forming surface. Exemplary coform processes are described in U.S. Pat. No. 4,100,324 to Anderson et al.; U.S. Pat. No. 4,587,154 to Hotchkiss et al.; U.S. Pat. No. 4,604,313 to McFarland et al.; U.S. Pat. No. 4,655,757 to McFarland et al.; U.S. Pat. No. 4,724,114 to McFarland et al.; U.S. Pat. No. 4,100,324 to Anderson et al.; and U.K. Patent GB 2,151,272 to Minto et al.
The term “disposable” is used herein to describe absorbent articles that are not intended to be laundered or otherwise restored or reused as an absorbent article after a single use.
The terms “disposed on,” “disposed along,” “disposed with,” or “disposed toward” and variations thereof are intended to mean that one element can be a separate structure bonded to or placed with or placed near another element.
The terms “elastic,” “elasticized,” “elasticity,” and “elastomeric” and derivatives thereof mean that property of a material or composite by virtue of which it tends to recover its original size and shape after removal of a force causing a deformation. Suitably, an elastic material or composite can be elongated by at least 50 percent of its relaxed length and will recover, upon release of the applied force, at least 40 percent of its elongation.
The term “extensible” refers to a material or composite which is capable of extension or deformation without breaking, but does not substantially recover its original size and shape after removal of a force causing the extension or deformation (i.e., less than 40 percent recovery). Suitably, an extensible material or composite can be elongated by at least 50 percent of its relaxed length.
The term “fiber” refers to a continuous or discontinuous member having a high ratio of length to diameter or width. Thus, a fiber may be a filament, a thread, a strand, or any other member or combination of these members.
The term “health/medical absorbent articles” includes a variety of professional and consumer health-care products including, but not limited to, products for applying hot or cold therapy, medical absorbent garments, bed pads, and the like.
The term “hydrophilic” describes materials which are wetted by aqueous liquids in contact with the materials. The degree of wetting of the materials can, in turn, be described in terms of the contact angles and the surface tensions of the liquids and materials involved. Equipment and techniques suitable for measuring the wetability of particular fiber materials or blends of fiber materials can be provided by a Calm SFA-222 Surface Force Analyzer System, or a substantially equivalent system. When measured with this system, materials having contact angles less than 90 degrees are designated “wettable” or hydrophilic, and fibers having contact angles greater than 90 degrees are designated “nonwettable” or “hydrophobic”.
The term “insult surface” describes the body-facing surface that will make first contact with a fluid insult.
The term “meltblown fibers” refers to fibers formed by extruding a molten thermoplastic material through a plurality of fine, usually circular, die capillaries as molten threads, fibers or filaments into a high velocity, usually heated, gas (e.g., air) stream which attenuates the filaments of molten thermoplastic material to reduce their diameter. Exemplary meltblown processes are described in various patents and publications, including NRL Report 4364, “Manufacture of Super-Fine Organic Fibers” by V. A. Wendt, E. L. Boone and C. D. Fluharty; NRL Report 5265, “An Improved Device For the Formation of Super-Fine Thermoplastic Fibers” by K. D. Lawrence, R. T. Lukas and J. A. Young; and U.S. Pat. No. 3,849,241 to Butin et al. and U.S. Pat. No. 5,350,624 to Georger et al., each of which is incorporated herein by reference.
The terms “nonwoven” and “nonwoven web” refer to materials and webs of material having a structure of individual fibers or filaments which are interlaid, but not in an identifiable manner as in a knitted fabric. The terms “fiber” and “filament” are used herein interchangeably. Nonwoven fabrics or webs have been formed from many processes such as, for example, meltblown processes, spunbond processes, air laying processes, wet laying processes and bonded-carded-web processes.
In the context of the present invention, the term “personal care absorbent articles” includes, but is not limited to, absorbent articles such as diapers, diaper pants, training pants, absorbent underpants, child care pants, and other disposable garments; feminine care products including menstrual pads, menstrual pants, panty liners, panty shields, interlabials; adult-care products including, pads such as breast pads, incontinence products, and urinary shields.
The term “pledget” in the context of the present invention refers to a portion cut from the web of stimulation composite 110 during a conversion process (either in-line or off-line the absorbent article production line).
The terms “spunbond” and “spunbonded fiber” refer to fibers which are formed by extruding filaments of molten thermoplastic material from a plurality of fine, usually circular, capillaries of a spinneret, and then rapidly reducing the diameter of the extruded filaments.
The term “target zone” is a pledget region to which a liquid insult is directed.
The term “% by weight,” “weight %,” “wt %” or derivative thereof, when used herein, is to be interpreted as based on the dry weight, unless otherwise specified.
The above mentioned terms may be defined with additional language in the remaining portions of the specification.
In the present invention, the unique structure of the stimulation composite provides user stimulation after at least one insult. This is done by partially bonding the stimulation material to fibers of adhesive through a meltblown application to reduce or prevent loss of the stimulation material from the stimulation composite as it is converted into pledgets and as it is used by consumers. In addition, because the insult target zone can be determined, it is possible to place the stimulation material into the most desirable areas of the pledget. In some cases, it may be desirable to have stimulation material uniformly cover entire pledget surface closest to the body-facing surface, by covering the area outside the target zone. However, in most cases, it is desirable to have the stimulation material partially cover the pledget area closest to the body-facing surface.
Desirably, the partial coverage is located away from areas of the pledget which are directly subjected to insult to reduce or substantially eliminate waste of the stimulation material. Further, such a configuration can provide either the same or an improved sensation as can uniform coverage. Therefore, not only can the present invention positively affect the stimulation experience as it relates to a targeted zone, it can also reduce manufacturing/converting costs by using significantly less amounts of the expensive stimulation material.
The improved material of this invention (hereinafter referred to as “stimulation composite”) is useful in personal care and health/medical disposable absorbent articles. An absorbent article of the present invention may have an absorbent core, and a topsheet and/or a backsheet. The absorbent core is disposed between the topsheet and the backsheet. The stimulation composite includes a garment-facing substrate to which a stimulation material and adhesive is attached thereto. In a most desired embodiment, the stimulation composite includes a body-facing, porous-substrate disposed on the body-facing surface of the stimulation blend.
Stimulation Composite
Referring to
The purpose of stimulation material 150 is to provide the user with a perceptible sensation when a fluid insult is occurring and/or has occurred. The sensation may be a discernable temperature change, a tingling sensation, pressure or any sensation that can alert the wearer that a liquid insult has occurred.
The stimulation material 150 can be of any practical form, but it is desirably in the form of a solid. As it refers to stimulation materials, the term “solid” can include particles, flakes, fibers, agglomerates, granules, powders, spheres, pulverized materials or the like, as well as combinations thereof. The solids can have any desired shape such as, for example, cubic, rod-like, polyhedral, spherical or semi-spherical, rounded or semi-rounded, angular, irregular, and the like.
A disposable absorbent article 20 (shown in
As can be appreciated, the stimulation composite 110 of the present invention can be described as having a total amount of stimulation material 150, by weight. For example, in some aspects, the stimulation composite 110 can include about 0.5 to 20 grams of stimulation material 150, or about 1 to 15 grams of stimulation material, or about 1 to 10 grams of stimulation material.
In some aspects, one can define a particle size distribution of stimulation material 150 within the stimulation composite 110. It should be understood that in aspects where the stimulation material is in the form of particles, the invention can include particles having sizes ranging from less than about 90 microns (including nanoparticles) to greater than about 710 microns, as measured by the Particle Size Test.
In general, the stimulation material 150 is responsive to contact with an aqueous solution such as urine, menses or other aqueous body exudates to provide a stimulating effect, such as the absorption or release of heat, pressure, a tingling sensation and the like. In general, the mechanism by which this is accomplished is by dissolution of the stimulation material 150 in the aqueous solution, or by reaction of the material 150 in the aqueous solution. For example, the stimulation material 150 may include particles that have a substantial energy difference between a dissolved state and a crystalline state so that energy in the form of heat is absorbed or released to the environment upon contact with liquid. The selection of a particular stimulation material 150 and the determination of the amount to be used should be based in part on the desired stimulation effect.
In some aspects, the stimulation material 150 of the various aspects of the present invention can include a substance that provides a temperature change (referred to herein as a “temperature change agent”) when contacted with an aqueous liquid and placed in indirect contact with the wearer's skin. “Indirect” because there may be one or more layers between the stimulation composite and the skin. In some aspects, the temperature change can be an absorption or release of heat that is noticeable to the wearer. Absorption of heat by the temperature change agent (also referred to herein as a “cooling agent”) will provide the wearer with a cool sensation, while a release of heat by the temperature change agent (also referred to herein as a “warming agent”) will provide the wearer with a warm sensation. Reference is made to U.S. Patent Application Publication No. 2004/0254549 to Olson, et al., incorporated herein by reference, for additional information regarding the mechanism by which the temperature change sensation is accomplished. The cooling agents or warming agents can be provided in particulate form for ease of processing in the described embodiments. To illustrate, in aspects where the stimulation material 150 is a temperature change agent, the stimulation composite 110 may suitably provide a temperature change (i.e., cooler, warmer or both) when insulted with an aqueous liquid of at least about 2° C., such as at least about 5° C., or at least about 10° C., or between 3° C. and 15° C.
In some aspects, the stimulation material 150 can include a temperature change agent in the form of a cooling agent, which can include those substances that absorb heat during dissolution from an insult. By way of example, polyols such as xylitol particles may be selected as cooling agents to provide a cooling sensation as xylitol particles absorb heat when dissolved in an aqueous liquid. Alternatively, other polyols such as sorbitol or erythritol may be advantageously selected to provide a cooling sensation. In yet other aspects, various combinations of the above stimulation materials 150 may be utilized.
Suitable polyols can be obtained from Roquette America, Inc., a company having offices in Keokuk, Iowa, U.S.A., under the trade name of XYLISORB (xylitol) or NEOSORB sorbitol. Such polyols can generally be obtained from the manufacturer in particular particle sizes, such as 90 microns, 300 microns, 500 microns, and 1000 microns and above.
Other suitable stimulation materials 150 that absorb heat during dissolution include salt hydrates, such as sodium acetate (H2O), sodium carbonate (H2O), sodium sulfate (H2O), sodium thiosulfate (H2O), and sodium phosphate (H2O); anhydrous salts such as ammonium nitrate, potassium nitrate, ammonium chloride, potassium chloride, and sodium nitrate; organic compounds such as urea and the like or combinations thereof.
In some aspects, the stimulation material 150 can include a temperature change agent in the form of a warming agent, which can include those substances that release heat during dissolution from an insult. Examples of materials that release heat during dissolution include manganese chloride, aluminum chloride, aluminum sulfate, potassium aluminum sulfate, and the like or combinations thereof. In some aspects, the warming agent can also include those substances that release heat during swelling.
The stimulation material 150 can also include ortho esters or ketals such as menthone ketals that result from reacting menthone with alcohols containing 1 to 8 carbons or polyols containing 2 to 8 carbons, and all structural and optical isomers thereof. Particular menthone ketals that may be suitable include menthone-glycerol ketal and menthone-propylene glycol ketal. Other suitable ketals are disclosed in U.S. Pat. No. 5,348,750 to Greenberg and U.S. Pat. No. 5,266,592 to Grub et al., which are incorporated herein.
The selection of a particular temperature change agent and the determination of the amount to be used should be based in part on the desired temperature change. For example, in some aspects, the total amount of stimulation material 150 present in the stimulation composite 110 can range from a basis weight of from about 40 gsm to about 3000 gsm, such as about 100 gsm to about 2000 gsm, or about 300 gsm to about 1000 gsm.
In addition, as referenced above, in some aspects, the disposable absorbent article 20 (
Temperature change agents that absorb or release heat on contact with an aqueous solution desirably have a heat of solution, hydration, or reaction greater than about 30 cal/g, or less than about −30 cal/g. The heat of solution, hydration, or reaction is suitably within the range of from about 30 to about 90 cal/g or from about −30 to about −90 cal/g, such as from about 30 to about 70 cal/g or from about −30 to about −70 cal/g, such as xylitol at −32 cal/g or urea at −60 cal/g.
In some circumstances, it may be desirable for the stimulation composite 110 to do more than just alert the user of an insult. Indeed, it may be desirable for the stimulation composite 110 to additionally provide a benefit to the user. For example, in addition to alerting the user of an insult, the stimulation device could also provide pH buffering for the skin, vaginal health-care for a female, odor control, coating materials for skin health, or even medicines.
Further, it may be desirable to use more than one stimulation material. For instance, a first stimulation material may cause a temperature change/sensation upon a first insult, and a second stimulation material may cause a temperature change/sensation upon a second insult due to the fact that the second stimulation material is in a different area. In the alternative, the two (or more) stimulation materials may be blended together. In one aspect, the first stimulation material has a temperature change upon a first liquid insult. A second stimulation material, having a need for more than one insult to for a physical or chemical reaction to occur (e.g. different solubility), may present a tingling sensation. Other combinations of stimulation material are within the scope of this invention.
In some aspects, a pledget of stimulation composite 110 can be adapted to provide the wearer with an expanding or contracting dimensional change sensation. Dimensional change elements of this type are described in more detail in U.S. Pat. No. 5,649,914 to Glaug et al., which is incorporated herein by reference in a manner that is consistent herewith. A pressure change agent in the form of a dimensional change material includes materials that rapidly undergo a change in at least one dimension when exposed to an aqueous solution. The dimensional change is suitably either as an expansion to at least about 2 times a dry dimension or as a contraction to less than about one-half (½) of the dry dimension. For example, the dimensional change material can have a wet height-dimension that is at least about 2 times greater than its dry height dimension, such as at least about 5 times greater for improved performance. The height dimension of the dimensional change material is in the z-direction 3 of the stimulation composite 110 so that the dimensional change is noticeable to the wearer of the absorbent article 20. In other aspects, the x-direction 1 and/or y-direction 2 of the stimulation composite 110 can additionally or alternatively remain the same, expand, or contract when exposed to an aqueous solution. Suitable materials for use in the dimensional change material include expandable foams, superabsorbents, or the like.
In some aspects, the pressure change agent produces a gas, such as carbon dioxide. Gas generating materials of this type are described in more detail in U.S. Pat. No. 7,002,055 to Long et al., which is incorporated herein by reference in a manner that is consistent herewith. The gas produced upon wetting with urine, complex fluids or other body exudates can produce a sound, a smell, a tingling sensation or apply pressure to the user.
In some aspects, the stimulation composite 110 can optionally include a surfactant. In some aspects, the gas producing materials can interact with the surfactant to produce a foam that applies pressure to the user. Thus, the surfactant component can be present as a foaming agent. For example, when a gas, such as carbon dioxide, is produced, the gas interacts with the surfactant and a bubble-filled foam is produced. These bubbles cause the article to swell and push against the skin of the wearer to alert the wearer of a liquid insult.
The surfactant used is not critical so long as it does not substantially irritate the skin upon contact, or adversely affect the efficacy of the stimulation material 150. A wide variety of surfactants may be suitable for use in accordance with the present invention. For example, suitable surfactants include anionic surfactants, nonionic surfactants, amphoteric surfactants, cationic surfactants, and combinations thereof. Examples of suitable anionic surfactants include alkyl benzene sulfonates, alkyl sulfates, alkyl ether sulfates, sulfosuccinates, and combinations thereof. Examples of suitable nonionic surfactants include ethoxylated alcohols, fatty acid alkanolamides, ethoxylated alkanolamides, amine oxides, and combinations thereof. Examples of suitable amphoteric surfactants include alkyl betaines, amidobetaines, and combinations thereof. Examples of suitable cationic surfactants include alkylammonium halides. In some aspects, the stimulation composite 110 can include from about 0.1 grams to about 15 grams of surfactant.
In other aspects, a pressure change agent in the form of a gas producing material can include an aqueous-soluble effervescent solid material. Such aqueous-soluble effervescent solid material typically comprises pressurized gas-containing cells. When the solid material having pressurized gas-containing cells is contacted with urine or other body exudates, the solid material begins to dissolve and the pressurized gas is released from the cells during dissolution of the solid material. In some aspects, this gas can interact with an optional surfactant and produce a foam and bubbles that cause the article 20 to press or apply pressure to the skin of the user.
In this aspect, the soluble effervescent solid material may include a sugar compound such as a mono-saccharide, di-saccharide, or poly-saccharide that has been infused with a gas that is substantially non-reactive with human skin. Suitable gases for infusion into a solid material include, for example, carbon dioxide, air, nitrogen, argon, helium, other substantially inert gases, and combinations thereof. Specific examples of saccharides that can be used in accordance with the present disclosure include glucose, fructose, sucrose, lactose, maltose, dextrin, cyclodextrin, and the like, or combinations thereof. Also, a mixture of sucrose with corn syrup (containing glucose, maltose, and dextrin) can be used in accordance with this aspect of the present disclosure to produce a gas-containing effervescent material. Other examples of compounds that are capable of being prepared in such a manner as to trap pressurized gas in cells include, for example, water soluble compounds such as salts, alkali halides, and alkaline earth metal halides. Specific salts useful in the present disclosure include, for example, sodium chloride, potassium chloride, potassium bromide, lithium chloride, cesium chloride, and the like. In some aspects, the cells containing the pressurized gas have a diameter of from about 5 micrometers to about 100 micrometers.
A substantially non-reactive gas can be infused into the cells of the soluble solid material to produce an effervescent material useful in the present invention by first heating the starting material, such as a sugar, in a small amount of water until the material is dissolved. After dissolution of the material, the water is evaporated off leaving the material in a molten state. The molten material is then gasified by introducing a suitable gas, such as carbon dioxide, at a superatmospheric pressure into a sealed vessel containing the molten material. The molten material is agitated during gasification to ensure intimate contact between the molten material and the gas. Pressures of, for example, between about 50 psig (340 kPa) and about 1000 psig (6890 kPa) may be utilized to infuse the gas into the molten material. After gas infusion, the molten material is allowed to solidify while maintained in the sealed vessel to produce an effervescent material. A suitable procedure of producing a gas-containing solid material is set forth in U.S. Pat. No. 4,289,794 to Kleiner et al., which is incorporated herein by reference in a manner that is consistent herewith. The above procedure can produce solid effervescent materials containing cells of pressurized gas from about 50 psig (340 kPa) to about 900 psig (6200 kPa) which, when exposed to urine, complex fluids or other body exudates, allow the release of the trapped gas.
In some aspects, the pressure change agent comprising a gas producing material includes at least one acid and at least one base. The acid and base react together upon being wetted to produce a gas that may be, for example, carbon dioxide gas. The exact gas produced by the gas producing system is not critical, so long as the gas produced is substantially non-harmful to the skin of the wearer.
In some aspects, the stimulation material 150 can be a gas-generating material that includes a polymeric acid and a complementary base, resulting in an acid-base reaction. Suitable acidic polymers should be readily water soluble or water-wettable. Examples of suitable polymeric acids include, but are not limited to, polyacrylic acids, polystyrene phosphorus acids, and the like. In some aspects, the polymeric acid can be a “bidentate” or higher order acid. By “bidentate or higher order” it is meant that the polymeric acid has more than one acid group in its smallest polymer building block. This can be easily understood when one compares ascorbic acid to tartronic acid (two acid groups) and citric acid (three acid groups). In some aspects, the polymeric acids may be a dendrimer or the like where the dendrimer's surface and interior are fully functionalized with acid groups.
Other examples of suitable acids include, but are not limited to, acetic acid, lactic acid, amino acid, ascorbic acid, glyolic acid, salicylic acid, tartaric acid, citric acid, EDTA, tartronic acid, polyacrylic acid, maleic acid, phosphonic acid, and the like. More materials such as these are referenced in U.S. application Ser. No. 12/646,763, filed on Dec. 23, 2009, incorporated herein.
Adhesives
Materials that make suitable thermoplastic adhesives include those that exhibit adhesive properties when transitioning from a molten state to a solid state. In some aspects, the adhesive composition is suitably a pressure-sensitive hot-melt adhesive 152. Such an adhesive generally comprises one or more polymers to provide cohesive strength, such as aliphatic polyolefins such as polyethylene-co-propylene, pol1ides, polyesters, and/or polyether blends; ethylene vinyl acetate copolymers; styrene-butadiene or styrene-isoprene block copolymers; and the like.
As an example, the pressure-sensitive hot-melt adhesive 152 may contain from about 15 to about 50 weight percent cohesive strength polymer or polymers; from about 30 to about 65 weight percent resin or other tackifier or tackifiers; from more than zero to about 30 weight percent plasticizer or other viscosity modifier; and optionally less than about 1 weight percent stabilizer or other additive. It should be understood that other hot-melt adhesive formulations comprising different weight percentages of these components are possible. It is also contemplated that the adhesive composition may either be hydrophilic or hydrophobic without departing from the scope of this invention.
Examples of suitable materials include hydrophobic and hydrophilic hot melt polymers, such as those available from National Starch and Chemical Co. (having a place of business located in Bridgewater, N.J., U.S.A.) such as 34-5610, 34-447A, 70-3998 and 33-2058; those available from Bostik-Findley (having a place of business located in Milwaukee, Wis., U.S.A.) such as HX 4207-01, HX 2773-01, H2525A, H2800, H9574; and those available from H.B. Fuller Adhesives (having a place of business located in Saint Paul, Minn., U.S.A.) such as HL8151-XZP. Other adhesives are further described in U.S. Patent Publication No. 2005/0096623 to Sawyer, et al., which is incorporated herein by reference in a manner that is consistent herewith.
It is also contemplated that alternative adhesives may be used without departing from the scope of this invention. Examples of alternative adhesives include polyethylene oxide (PEO); polyethylene glycol (PEG); polyviny alcohol (PVOH); starch derivatives such as starch ethers, carboxymethyl starch, cationic starch, hydroxyalkyl starch, and the like, for example hydroxyethyl starch, hydroxypropyl starch and hydroxybutyl starch; cellulose derivatives such as cellulose ethers, hydroxyalkyl cellulose, for example hydroxyethyl cellulose, hydroxypropyl cellulose, methylcellulose, methyl propyl cellulose, carboxymethyl cellulose, and the like; polyacrylic acid; polyvinylmethyl ether; carrageenan; water-soluble alkyd resins; or the like, ethylene vinyl acetate copolymer (EVA) and combinations thereof. In addition, thermoplastic adhesive fibers, such as thermoplastic binder fibers, can also be used.
The basis weight of each thermoplastic meltblown adhesive 152 can range from about 1 gsm to about 150 gsm, such as about 20 gsm to about 100 gsm. In still other aspects, the total amount of thermoplastic adhesive in the thermoplastic meltblown adhesive 152 can be about 2-15 wt % of the total weight of all stimulation material in the stimulation blend 156.
Substrates
Referring to
Each of the substrates 154 and 155 can suitably have a basis weight of about 10 gsm to about 100 gsm, such as about 10 gsm to about 80 gsm, or about 10 gsm to about 50 gsm. The substrates 154 and 155 may be identical or different materials.
Physical Characteristics of the Stimulation Composite
Referring to
In one aspect, the liquid permeable network of meltblown pressure-sensitive hot-melt adhesive 152 used in the present invention (described supra) allows liquid to transfer though the stimulation composite 110 (when substrates 154 and 155 are also porous). In some aspects, the porosity of the substrates 154 and 155 and may be enhanced by piercing the stimulation composite 110 from the body-facing side 187 through the opposite garment-facing side 188, such as by a needle punch (see
Referring to
Referring to
Patterns
There is an opportunity to make pre-determined functional patterns and/or aesthetic patterns defined by raised sections of stimulation blends 156, (should they be thick enough to be discernable). Either way, there is an opportunity to use pre-determined patterns of stimulant blend 156 such that the same stimulation effects can be obtained with less stimulation material 150. Further, patterns defining a predetermined insult pathway may be used to direct liquid insult(s) away from the target zone to achieve a sensation away from the target zone.
The surface area defined by the x-y plane of the body-facing side of a pledget of stimulation composite 110 includes a target zone where fluids are introduced upon insult. A first stimulation material 150 may be strategically located with respect to the target zone. A second stimulation material may be located in a second area with respect to the target zone and the first stimulation material. These separate areas provide an opportunity for delivering a sensation after not just one insult, but in addition, a second insult. Typically the first insult will define a first target zone, and the second insult will define a second target zone which is larger than the first target zone.
Referring to
In other aspects (not shown), the patterns made by certain placement of stimulation blend 156 includes concentric rectangles, concentric ovals, concentric circles, wavy lines, cross pattern, stripes and combinations thereof. In one aspect, the overall pattern is symmetric with respect to a machine direction (y-direction) of the absorbent article. In yet another aspect, the pattern is symmetric with respect to a cross-machine direction (x-direction).
In another aspect as seen in
It is noted that while most of the patterns formed with stimulation blend 156 are shown to be symmetrical in at least one direction in the x-y plane, it is not necessary to have a symmetrical design. The symmetry may be aesthetic or functional.
In one aspect, the stimulation blend 156 covers 10 to 90 percent of the surface area of the stimulation composite 110, or 20 to 60 percent of the surface area of the stimulation composite 110, or 40 to 50 percent of the surface area of the stimulation composite 110.
In another aspect, the stimulation blend 156 covers 20 to 100 percent of surface area of the stimulation composite 110, or 20 to 40 percent of the surface area of the stimulation composite 110.
In another aspect, the pressure-sensitive adhesive covers 95 to 100 percent of the surface area of the stimulation composite 110. Space between the areas containing stimulation blend 156 may be about 0 to 25 mm or about 5 to 15 mm or about 10 mm.
It is noted that regions of stimulation blend 156 are not sharply defined, and it is possible for insignificant amounts of stimulation material 150 to be located between the areas containing significant amount of stimulation blend 156. Relative to the stimulation blend 156, the stimulation material 150 fades to a small percentage in the areas of pressure-sensitive hot-melt adhesive 152. In one aspect, there may be about 0 to 10 percent of the stimulation material between the regions of stimulation blend 156.
It is noted that the adhesive 152 may not be significantly bound to any stimulation material 150. For example, the adhesive 152 located between stripes of stimulation blend 156 as seen in
Method of Making a Stimulation Composite
In general, construction of the stimulation composite 110 of the present invention can be accomplished by any suitable method well-known to those skilled in the art. In one aspect, a stimulation material 150 is partially bonded to the meltblown pressure-sensitive adhesive 152 to form a stimulation blend 156. The stimulation blend 156 can appear as raised sections if thick enough to be visually detected at the body-facing surface 187 (see
Referring to
Desirably, the particulate feeder 121 is a modified CHRISTY Dry Material Dispensing Machine in which the unmodified portion is available from the Christy Machine Company of Freemont, Ohio, U.S.A. Together, the particulate feeder 121 and the adhesive applicators 123A, B define a deposit system 125.
In operation, the deposit system 125 serves to deposit stimulation material 150 (and/or any other beneficial additives) into an adhesive fiber stream, thereby forming a stimulation blend 156. Stimulation blend 156 may fully cover the substrate 154, or may cover only sections of substrate 154.
Desirably, there is a second substrate 155 applied to substrate 154. The stimulation composite 110 passes through a nip roll 131 and optionally, a needle punch 133 (should the permeability of substrates 154 and 155 not be high enough without the punch).
The resulting stimulation composite has three layers, a) a bottommost layer of substrate 154, which is desirably a liquid-permeable nonwoven material located on the garment-facing side of the absorbent article 20, b) a middle layer of comingled meltblown pressure-sensitive adhesive 152 and stimulation material 150, and c) the topmost layer of substrate 155, which is desirably a liquid-permeable nonwoven or other material located on the body-facing side of the absorbent article 20.
Desirably, the stimulation composite 110 has a ratio of meltblown pressure-sensitive adhesive 152 comingled with the stimulation materials 150 of about 15/85, or in another aspect about 10/90, or in yet another aspect about 5/95. Most desirably, the ratio of meltblown pressure-sensitive adhesive to stimulation materials is about 2/98.
The web of stimulation composite 110 may be rewound and eventually unwound for conversion into pledgets of stimulation composite 110, only a few of which are shown in
Referring to
Referring now to
The particle channel attachment 300 may have channels 306 of the same shape and size as shown in
Referring to the examples shown in
Referring to
Desirably, the particle channel attachment 300 (including channels 306) and panels 304 are made of a metal that does not react with the particulate matter passing through the particle feeder 121, e.g. stainless steel.
Referring back to
Exemplary Absorbent Articles
To gain a better understanding of the present invention, attention is directed to
Various materials and methods for constructing training pants are disclosed in U.S. Pat. No. 6,761,711 to Fletcher et al.; U.S. Pat. No. 4,940,464 to Van Gompel et al.; U.S. Pat. No. 5,766,389 to Brandon et al., and U.S. Pat. No. 6,645,190 to Olson et al., each of which is incorporated herein by reference.
The training pant 20 defines a front region 22, a back region 24, and a crotch region 26 extending longitudinally between and interconnecting the front and back regions. The pant 20 also defines an inner surface (i.e., body-facing surface) adapted in use (e.g., positioned relative to the other components of the pant) to be disposed toward the wearer, and an outer surface (i.e., garment-facing surface) opposite the inner surface. The training pant 20 has a pair of laterally opposite side edges and a pair of longitudinally opposite waist edges.
The illustrated pant 20 may include a chassis 32, a pair of laterally opposite front side panels 34 extending laterally outward at the front region 22 and a pair of laterally opposite back side panels 734 extending laterally outward at the back region 24.
The chassis 32 includes a backsheet 40 and a topsheet 42 that may be joined to the backsheet 40 in a superimposed relation therewith by adhesives, ultrasonic bonds, thermal bonds or other conventional techniques. The chassis 32 may further include an absorbent core 44 such as shown in
The backsheet 40, the topsheet 42 and the absorbent core 44 may be made from many different materials known to those skilled in the art. All three layers, for instance, may be extensible and/or elastically extensible. Further, the stretch properties of each layer may vary in order to control the overall stretch properties of the product.
The backsheet 40, for instance, may be breathable and/or may be fluid impermeable. The backsheet 40 may be constructed of a single layer, multiple layers, laminates, spunbond fabrics, films, meltblown fabrics, elastic netting, microporous webs or bonded-carded-webs. The backsheet 40, for instance, can be a single layer of a fluid impermeable material, or alternatively can be a multi-layered laminate structure in which at least one of the layers is fluid impermeable.
The backsheet 40 can be biaxially extensible and optionally biaxially elastic. Elastic non-woven laminate webs that can be used as the backsheet 40 include a non-woven material joined to one or more gatherable non-woven webs or films. Stretch bonded laminates (SBL) and neck bonded laminates (NBL) are examples of elastomeric composites.
Examples of suitable nonwoven materials are spunbond-meltblown fabrics, spunbond-meltblown-spunbond fabrics, spunbond fabrics, or laminates of such fabrics with films, or other nonwoven webs. Elastomeric materials may include cast or blown films, meltblown fabrics or spunbond fabrics composed of polyethylene, polypropylene, or polyolefin elastomers, as well as combinations thereof. The elastomeric materials may include PEBAX elastomer (available from AtoFina Chemicals, Inc., a business having offices located in Philadelphia, Pa. U.S.A.), HYTREL elastomeric polyester (available from Invista, a business having offices located in Wichita, Kans. U.S.A.), KRATON elastomer (available from Kraton Polymers, a business having offices located in Houston, Tex., U.S.A.), or strands of LYCRA elastomer (available from Invista), or the like, as well as combinations thereof. The backsheet 40 may include materials that have elastomeric properties through a mechanical process, printing process, heating process or chemical treatment. For example, such materials may be apertured, creped, neck-stretched, heat activated, embossed, and micro-strained, and may be in the form of films, webs, and laminates.
One example of a suitable material for a biaxially stretchable backsheet 40 is a breathable elastic film/nonwoven laminate, such as described in U.S. Pat. No. 5,883,028, to Morman et al., incorporated herein by reference in a manner that is consistent herewith. Examples of materials having two-way stretchability and retractability are disclosed in U.S. Pat. No. 5,116,662 to Morman and U.S. Pat. No. 5,114,781 to Morman. These two patents describe composite elastic materials capable of stretching in at least two directions.
The topsheet 42 is also sufficiently liquid permeable to permit liquid body exudates to readily penetrate through its thickness to the absorbent core 44. A suitable topsheet 42 may be manufactured from a wide selection of web materials, such as porous foams, reticulated foams, apertured plastic films, woven and non-woven webs, or a combination of any such materials. For example, the topsheet 42 may include a meltblown web, a spunbonded web, or a bonded-carded-web composed of natural fibers, synthetic fibers or combinations thereof. The topsheet 42 may be composed of a substantially hydrophobic material, and the hydrophobic material may optionally be treated with a surfactant or otherwise processed to impart a desired level of wetability and hydrophilicity.
The topsheet 42 may also be extensible and/or elastomerically extensible. Suitable elastomeric materials for construction of the topsheet 42 can include elastic strands, LYCRA elastics, cast or blown elastic films, nonwoven elastic webs, meltblown or spunbond elastomeric fibrous webs, as well as combinations thereof. Examples of suitable elastomeric materials include KRATON elastomers, HYTREL elastomers, ESTANE elastomeric polyurethanes (available from Noveon, a business having offices located in Cleveland, Ohio, U.S.A.), or PEBAX elastomers. The topsheet 42 can also be made from extensible materials such as those described in U.S. Pat. No. 6,552,245 to Roessler et al. which is incorporated herein by reference. The topsheet 42 can also be made from biaxially stretchable materials as described in U.S. Pat. No. 6,969,378 to Vukos et al. which is incorporated herein by reference.
The article 20 can optionally further include a surge management layer which may be located adjacent the absorbent core 44 and attached to various components in the article 20 such as the absorbent core 44 or the topsheet 42 by methods known in the art, such as by using an adhesive. In general, a surge management layer helps to quickly acquire and diffuse surges or gushes of liquid that may be rapidly introduced into the absorbent structure of the article. The surge management layer can temporarily store the liquid prior to releasing it into the storage or retention portions of the absorbent core 44. Examples of suitable surge management layers are described in U.S. Pat. No. 5,486,166 to Bishop et al.; U.S. Pat. No. 5,490,846 to Ellis et al.; and U.S. Pat. No. 5,820,973 to Dodge et al., each of which is incorporated herein by reference.
The article 20 can further comprise an absorbent core 44. The absorbent core 44 may have any of a number of shapes. For example, it may have a 2-dimensional or 3-dimensional configuration, and may be rectangular shaped, triangular shaped, oval shaped, race-track shaped, I-shaped, generally hourglass shaped, T-shaped and the like. It is often suitable for the absorbent core 44 to be narrower in the crotch portion 26 than in the rear 24 or front 22 portion(s). The absorbent core 44 can be attached in an absorbent article, such as to the backsheet 40 and/or the topsheet 42 for example, by bonding means known in the art.
The absorbent core 44 can be formed using methods known in the art. While not being limited to the specific method of manufacture, the absorbent core can utilize forming drum systems, for example, see U.S. Pat. No. 4,666,647 to Enloe et al., U.S. Pat. No. 4,761,258 to Enloe, U.S. Pat. No. 6,630,088 to Venturino et al., and U.S. Pat. No. 6,330,735 to Hahn et al., each of which is incorporated herein by reference.
In some desirable aspects, the absorbent core includes cellulose fiber and/or synthetic fiber, such as meltblown fiber, for example. Thus, in some aspects, a meltblown process can be utilized, such as to form the absorbent core in a coform line. In some aspects, the absorbent core 44 can have a significant amount of stretchability. For example, the absorbent core 44 can comprise a matrix of fibers which includes an operative amount of elastomeric polymer fibers. Other methods known in the art can include attaching superabsorbent polymer particles to a stretchable film, utilizing a nonwoven substrate having cuts or slits in its structure, and the like.
The absorbent core 44 can additionally or alternatively include absorbent and/or superabsorbent material. Accordingly, the absorbent core 44 can comprise a quantity of superabsorbent material and optionally fluff contained within a matrix of fibers.
It should be understood that the absorbent core 44 is not restricted to use with superabsorbent material and optionally fluff. In some aspects, the absorbent core 44 may additionally include materials such as surfactants, ion exchange resin particles, moisturizers, emollients, perfumes, fluid modifiers, odor control additives, and the like, and combinations thereof. In addition, the absorbent core 44 can include foam.
While a training pant has been described above for exemplary purposes, it is understood that the stimulation blend of the present invention can be suitable for other personal care absorbent articles. For example,
The pledget of stimulation composite 110 as illustrated in the absorbent article figures is generally rectangular. However, as noted above, the pledget can have any of a number of shapes, including but not limited to those shown in
In some aspects, the stimulation composite 110 can be attached in an absorbent article, such as to the absorbent core, a surge layer and/or a topsheet for example, by bonding means known in the art, such as ultrasonic, pressure, adhesive, aperturing, heat, sewing thread or strand, autogenous or self-adhering, or the like, and combinations thereof. In other aspects, the stimulation composite may be free-floating within the article.
Referring to
In one embodiment, the pledget of stimulation composite 110 may be sized so that the pledget fits between the containment flaps 46. One reason for this is that the insulted portion of the diaper tends to sag, sometimes leaving the containment flaps 46 in contact with the skin. As such, one possible target zone could be the edges of a pledget on which there is contact with the pledget of stimulation composite 110. Further, it is contemplated that there could be separate stripes (not shown) of stimulation composite 110 disposed in regions of absorbent articles that remain in contact with the skin after an insult has occurred.
This example is a thermal imaging study of an absorbent article of the present invention (see
For example,
It can be concluded that all of the patterned samples (Codes S, B and D) are comparable to the control. The patterned stimulation composite are made with significantly less material, leading to a significant cost savings.
In addition to the cost savings, it can be seen that the xylitol is washed away from the yellow-orange target zone 502 where the insult was directed. This is a clue that the most efficient patterns of stimulation blend 156 might be those that do not have a significant amount of stimulation material in the pledget target zone. (Note that the region to which the insult is directed is likely to be gender specific.) It may be concluded that the stimulation material is best placed in the pledget regions that lie outside of the target zone 502 and which maintain skin contact after an insult has occurred. For instance, the blue areas 500 as seen in
Test Methods
Unless otherwise noted, all tests are performed at a temp of 23±2° C. and a relative humidity of 50±5%.
For the test, samples of stimulation composite 110 were made with the following steps:
The test was a controlled, randomized, bench trial wherein saline was applied to the absorbent pant 20 (see below). The test objective was to see where stimulation material 150 migrated to due to fluid insult, and to determine the cooling effectiveness and temperature profile of each code.
In general, three samples per code of disposable, size 2, HUGGIES brand training pants were tested on a size 2 mannequin warmed to body temperature, 37 C (98.6 F). Likewise, a fluid insult of 0.9% saline was heated to body temperature, 37 C (98.6 F). Each training pant was loaded with 75 mL of the 0.9% saline at a rate of 900 ml/minute into each sample in the same target zone location.
At 30 seconds post insult, a Mikron 7200V infrared thermal imaging camera (obtained from Mikron Technology Inc. of Oakland, N.J., U.S.A.) was used to collect the thermal images seen in
Procedure Steps
A stack of sieves are used to determine the particle size distribution of a given sample. Thus, for example, a particle that is retained on a sieve with 710 micron openings is considered to have a particle size greater than 710 microns. A particle that passes through a sieve having 710 micron openings and is retained on a sieve having 500 micron openings is considered to have a particle size between 500 and 710 microns. Further, a particle that passes through a sieve having 500 micron openings is considered to have a particle size less than 500 microns, and so on.
The sieves are placed in order of the size of the openings with the largest openings on the top of the stack and the smallest openings on the bottom of the stack. Thus, all of the stimulation material associated with a stimulation blend can be weighed and placed into the sieve with the largest openings. Alternatively, if it is desired to determine the particle size or particle size distribution of the stimulation material in only a particular portion of the stimulation blend, only the stimulation material associated with that portion can be weighed and placed into the sieve with the largest openings. U.S. Standard sieves can be used in the sieve stack, including 20 mesh (850 microns), 25 mesh (710 microns), 35 mesh (500 microns), 50 mesh (300 microns) and 170 mesh (90 microns).
The sieve stack is shaken for 10 minutes with a Ro-Tap mechanical Sieve Shaker, Model RX29 available from W.S. Tyler of Mentor, Ohio, U.S.A. or other similar shaking device at standard test conditions. After shaking is complete, the stimulation material retained on each sieve is removed and the weight is measured and recorded. The percentage of particles retained on each sieve is calculated by dividing the weights of the particles retained on each sieve by the initial sample weight.
The thickness value of a selected portion or section of an article is determined using a thickness tester such as seen in
To perform the procedure, a block 2370 having a length of 50 mm and a width of 44 mm is placed onto the granite base 2320. The block 2370 is constructed of acrylic and is flat and smooth on at least the bottom surface 2372. The thickness and weight of the block 2370 is configured such that the thickness tester 2310 provides a pressure to the sample of 0.69 kPa (0.1 psi). Next, the thickness tester 2310 is gently lowered such that the bottom surface 2362 of the plunger 2360 is in direct contact with the top surface 2374 of the block 2370 at the longitudinal 1 and transverse 2 center of the block 2370, and the plunger length is shortened by about 50%. The digital indicator 2350 is then tared (or zeroed) by pressing the “zero” button 2357. The digital display 2355 of the digital indicator 2350 should display “0.00 mm” or equivalent. The thickness tester 2310 is then raised and the block 2370 is removed. The test sample is then placed onto the top surface 2322 of the granite base 2320 and the block 2370 is gently placed on top of the test sample such that the block 2370 is substantially centered longitudinally 1 and transversely 2 on the sample. The thickness tester 2310 is then gently lowered again onto the block 2370 such that the bottom surface 2362 of the plunger 2360 is in direct contact with the top surface 2374 of the block 2370 at the longitudinal 1 and transverse 2 center of the block 2370, and the plunger length is shortened by about 50%, to provide a pressure of 0.69 kPa (0.1 psi). After 3 seconds, the measurement from the digital display 2355 is recorded to the nearest 0.01 mm.
Although the invention has been described with reference to preferred embodiments, persons skilled in the art will recognize that changes may be made in form and detail without departing from the spirit and scope of the invention.
The dimensions and values disclosed herein are not to be understood as being strictly limited to the exact numerical 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, unless otherwise stated, 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.
