Patent Application
20050148987
Disposable garments, including disposable absorbent garments, have been known for decades. Disposable garments may include garments worn like underpants for children and adults, garments worn like training pants for toddlers and garments worn like diapers for infants. Disposable absorbent garments designed to absorb and contain bodily fluids may include adult/child incontinence garments, toddler training pants and infant diapers. “Disposable” is generally understood to mean something that has a limited period of use before its ability to perform its intended function is exhausted. With regard to garments, “disposable” garments typically are not constructed to withstand laundering.
Typically, it is desirable for disposable garments to fit close to the body of the wearer for comfort and discretion. The disposable garment may have or form an opening that fits around the user's waist, as well as two openings that fit around the user's legs. The disposable garment typically includes a front waist region, a back waist region and a crotch region that extends between and connects the front and back waist regions. The front waist region includes the portion of the disposable garment that, when worn, is positioned on the front of the user while the back waist region includes the portion of the disposable garment that, when worn, is positioned on the back of the user. The crotch region of the disposable garment includes the portion of the disposable garment that, when worn, is positioned between the legs of the user and covers the lower torso of the user. Disposable garments may include one or more layers of materials, such as nonwoven materials. For example, a disposable garment may include a liner material that forms the layer of material closest to the user's skin and an outer material that forms the layer of material closest to the user's other clothing. Disposable garments may also include features that improve how well the garments fit the user. For example, disposable garments may include stretchable, such as elastic, materials near the waist opening and leg openings of the garment to improve the fit of the garment around the user's waist and legs. Additionally, disposable garments may include fasteners that assist with securing the position of the garment in use. For example, disposable garments may include adhesive or mechanical fasteners to assist with securing the garments around the waists of the users. Disposable garments may include additional features that improve the fit range (i.e. the range of users able to wear a particular size of absorbent garment) of the garments.
Disposable absorbent garments may be similar to disposable garments and provide the ability to absorb and contain bodily fluids such as urine, feces and menses. In addition to one or more layers of materials similar to disposable garments, disposable absorbent garments may also include an absorbent material. For example, if a disposable absorbent garment includes a single layer of material, the absorbent material may be located on the side of the single layer of material that will be positioned closest to the user's skin during wear. A representative example of a commonly used disposable absorbent garment is a disposable diaper to be used by an infant or toddler. Disposable diapers may have various shapes when they are open or unfastened and laying generally flat. For example, disposable diapers may have an overall rectangular shape, T-shape, I-shape or hourglass shape. Disposable absorbent garments, such as infant diapers, have a longitudinal direction that generally corresponds to the length of the garments and a lateral direction that generally corresponds to the width of the garments. Disposable absorbent garments typically include at least four edges: a pair of laterally opposed side edges and a pair of longitudinally opposed waist edges. Disposable absorbent garments may include an interior surface that is configured to contact the user's skin during wear and an exterior surface opposite the interior surface that is configured to contact the user's clothing during wear.
Presently available disposable diapers include at least three layers: a substantially liquid impermeable outer cover (a.k.a. a “backsheet”), a liquid permeable bodyside liner (a.k.a. a “topsheet”) that can be connected to the outer cover in a superposed relation and an absorbent core (or absorbent “body”) that is located between the outer cover and the bodyside liner. The side edges of the outer cover generally define the laterally opposed side edges of the disposable diaper and the side edges may form curvilinear leg openings when the disposable diaper is worn. The waist edges of the outer cover generally define the waist edges of the disposable diaper and typically form the waist opening that is configured to encircle the waist of the user when the disposable absorbent garment is worn. The absorbent core is configured to contain and/or absorb body exudates discharged from the user. Presently-available disposable diapers typically include waist elastics, leg elastics and containment flaps. Presently-available disposable diapers further include adhesive tape fasteners or refastenable mechanical fasteners (or combinations of both) for releasably engaging the opposed side edges of the disposable diaper in the opposite waist regions. The mechanical fasteners can include a variety of materials and surfaces known for mechanical engagement such as buttons, pins, snaps, cohesives, mushroom-and-loop fasteners and hook and loop fasteners. Many disposable diapers also include an attachment panel located on the front or back waist region, opposite the fasteners to which the fasteners can be releasably engaged while the disposable diaper is worn.
While disposable garments and disposable absorbent garments have been known for many years, the materials used to construct them have continuously evolved as a result of new technologies for formulating and manufacturing disposable materials. Materials may be selected for performance or to provide a cost advantage, particularly given that many manufacturers produce disposable garments and disposable absorbent garments in very large quantities. One aspect of evolution has been the development and availability of stretchable materials to replace previously non-stretchable components in order to provide improvements in the way in which the garments fit and improvements in the range of fit of the garments. An example of a stretchable material for use in disposable garments is a necked bonded laminate material (hereinafter “NBL material”). One of the first uses identified for a stretchable material, such as a NBL material, in the construction of a disposable diaper was as an “ear” material where the “ear” was attached to the longitudinal side edge of the diaper in the back waist region and to which was attached a mechanical fastener engageable with the front waist region.
Stretchable materials may include materials that are extensible and materials that are elastic. “Extensible” materials typically have lower capacities to retract to their original lengths after stretching while “elastic” materials typically have a greater range of stretch and come close to completely retracting to their original lengths after stretching. Presently-available disposable diapers, including HUGGIES Supreme diapers manufactured by Kimberly-Clark Corporation, are constructed with an extensible outer cover material and an extensible bodyside liner material.
With the advent of the availability of stretchable materials to construct disposable absorbent garments, various configurations for garments incorporating stretchable materials have been described. For example, once a stretchable material is selected to form a component of a garment, the material may be modified to provide a range of stretch characteristics. International Publication No. WO 99/33427 (hereinafter “the 33427 publication”) describes personal care articles that may include resiliently stretchable outer covers and/or resiliently stretchable bodyside liners. The 33427 publication describes that the resiliently stretchable materials may be “embossed” to modify the “resistance to stretch” properties. The “embossments” may be used to reduce or otherwise control the stretching of different portions or “zones” of the garments. Therefore, in addition to stretchable materials themselves being available for use in absorbent garments, the potential for some forms of modification of the stretch properties has also been described.
In addition to garments utilizing extensible and otherwise stretchable materials, garments utilizing elastic materials have been described. International Publication No. WO 02/34184 (hereinafter “the 34184 publication”) describes absorbent garments that may have a biaxially stretchable outer cover and a biaxially stretchable bodyside liner. The “biaxially stretchable” materials described as being suitable in the 34184 publication include elastic materials capable of stretching in at least two directions.
Simultaneous with the development of stretchable materials having lower cost and/or improved properties for use in disposable garments, developments with regard to the structural features of disposable garments have also occurred. Just as stretchable ears were developed to improve the fit of garments, other features have been developed to improve the waste containment function of the garments. An example of one such class of features is the provision of holes or apertures between layers of the garments to separate the waste materials from the wearer's skin. More specific examples of such features are apertures or openings in the bodyside liners of disposable absorbent garments that are provided to separate solid wastes from the wearer's skin to reduce the incidence of troublesome conditions such as diaper rash.
Even though significant and numerous advancements have occurred in the materials and structural features available for the construction of disposable garments, there remain opportunities for improvement in the fit and containment capacity of such garments. For example, there remains a need for a disposable garment that provides excellent fit on the wearer that results in reduced leakage and that provides a barrier between the wearer's skin and the waste materials being contained by the garment. Additionally, there remains a need for a disposable garment that has a simplified construction and that eliminates the attachment of multiple separate components that increase the cost and complicate the manufacture of disposable garments.
The present invention relates generally to disposable absorbent garments. The disposable absorbent garments may have a longitudinal direction and a lateral direction. The longitudinal direction generally corresponds to the length of the garment and the lateral direction generally corresponds to the width of the garment. The longitudinal direction and the lateral direction are generally perpendicular to each other. The disposable absorbent garments may include a front waist region, a back waist region and a crotch region that connects the front waist region and the back waist region. The disposable absorbent garment may further include an elastic inner layer and an absorbent assembly. The elastic inner layer may have an elastic inner layer perimeter that forms two longitudinal side edges and two lateral waist edges. The elastic inner layer perimeter corresponds generally to the outer edges or boundaries of the generally planar elastic inner layer perimeter. The elastic inner layer may define an opening that is located in an internal position to the elastic inner layer perimeter. The opening may be in the form of a slit or an aperture. The elastic inner layer may have an interior surface and an exterior surface. The interior surface may be the surface that comes into contact with the skin of the wearer of the garment. The exterior surface may be the surface that is in closest proximity to the garment wearer's clothing. The exterior surface of the elastic inner layer in the front waist region may include a fastener. A fastener may be located laterally inward of the longitudinal side of the garment. The interior surface of the elastic inner layer in the back waist region may also include a fastener located laterally inward of the longitudinal side edge. The absorbent assembly may be attached to the exterior surface of the elastic inner layer. The absorbent assembly may include a topsheet layer, a core layer and a barrier layer.
The elastic inner layer may be formed of a material that is elastic in the lateral direction. Elastic materials are generally understood to be materials that are capable of stretching and of substantially returning to their original length when a pulling force is removed. The elastic inner layer may also be formed of a material that is elastic in both the longitudinal direction and the lateral direction. The elastic inner layer may be formed of a material that is liquid impermeable. The elastic inner layer may include two or more layers of materials. The elastic inner layer may be continuous or alternatively, the elastic inner layer may include a front piece, a back piece and a crotch piece. The crotch piece may be attached to the front piece and the back piece. The front piece and the back piece may be elastic in the lateral direction of the disposable absorbent garment. The crotch piece may be elastic in the longitudinal direction of the disposable absorbent garment. The opening that is formed within the elastic inner layer may have a length of from about 10 percent to about 80 percent of the total length of the garment.
The disposable absorbent garment may also include an outer layer. The outer layer may be in superposed relationship with the exterior surface of the elastic inner layer. The outer layer may have an outer layer perimeter. The outer layer perimeter may be bonded to the elastic inner layer perimeter. The elastic inner layer perimeter may be bonded to the outer layer perimeter by a plurality of ultrasonic, adhesive or thermal bonds. The longitudinal side edges of the elastic inner layer may form leg cuffs of the disposable absorbent garment. Additionally, the longitudinal side edges of the topsheet layer and the barrier layer may extend laterally outward so that they may be gathered and form leg cuffs.
In another aspect, the present invention relates to a disposable absorbent garment having a longitudinal direction and a lateral direction. The disposable absorbent garment may include a front waist region, a back waist region and a crotch region that connects the front waist region and the back waist region. The disposable absorbent garment may include an elastic inner layer and an absorbent assembly. The elastic inner layer may have an elastic inner layer perimeter where the perimeter forms two longitudinal side edges and two lateral waist edges. The elastic inner layer may define an opening that is located in an internal position to the elastic inner layer perimeter. The elastic inner layer may be generally planar and may have an interior surface and an exterior surface. The interior surface of the elastic inner layer is the surface that comes into contact with the skin of the wearer of the garment. The disposable absorbent garment may further include a front ear portion bonded to each longitudinal side edge in the front waist region. The front ear portions may have an interior surface and an exterior surface that correspond with the interior surface and exterior surface of the elastic inner layer. The front ear portions may include fasteners on their exterior surfaces. The garment may also include a back ear portion bonded to each longitudinal side edge in the back waist region. The back ear portions may also have an interior surface and an exterior surface that likewise correspond with the interior surface and exterior surface of the elastic inner layer. The back ear portions may include fasteners on their interior surfaces. The absorbent assembly may be attached to the exterior surface of the elastic inner layer. The absorbent assembly may include a topsheet layer, a core layer and a barrier layer.
In yet another aspect, the present invention relates to a disposable absorbent garment having a longitudinal direction and a lateral direction. The disposable absorbent garment may include a front waist region, a back waist region and a crotch region that connects the front waist region and the back waist region. The disposable absorbent garment may also include an elastic inner layer and an absorbent assembly. The elastic inner layer may have an elastic inner layer perimeter and the elastic inner layer perimeter may form two longitudinal side edges and two lateral waist edges. The elastic inner layer may define an opening that is located in an internal position to the elastic inner layer perimeter. The elastic inner layer is generally planar and may have an interior surface and an exterior surface. The exterior surface of the elastic inner layer may include a fastener in the front waist region that is located laterally inward of the longitudinal side edge. The elastic inner layer may also include a fastener located laterally inward of the longitudinal side edge on the interior surface in the back waist region. The absorbent assembly may be attached to the exterior surface of the elastic inner layer. The absorbent assembly may include a topsheet layer, a core layer and a barrier layer. The longitudinal side edges of the elastic inner layer may form leg cuffs.
In a further aspect, the present invention relates to a disposable absorbent garment having a longitudinal direction and a lateral direction. The disposable absorbent garment may include a front waist region, a back waist region and a crotch region that connects the front waist region and the back waist region. The disposable absorbent garment may include an elastic inner layer and an absorbent assembly. The elastic inner layer may include an elastic inner layer perimeter and the elastic inner layer perimeter may form two longitudinal side edges and two lateral waist edges. The elastic inner layer may be formed of a material that is elastic in both the longitudinal direction and the lateral direction. The elastic inner layer may define an opening that is located in an internal position to the elastic inner layer perimeter. The opening may have a length of from about 10 percent to about 80 percent of a total length of the disposable absorbent garment. The elastic inner layer is generally planar and may have an interior surface and an exterior surface. The disposable absorbent garment may include a front ear portion bonded to each longitudinal side edge in the front waist region. The front ear portions may have an interior surface and an exterior surface that correspond to the interior surface and exterior surface of the elastic inner layer. The front ear portions may include fasteners on their exterior surfaces. The disposable absorbent garment may also include a back ear portion bonded to each longitudinal side edge in the back waist region. The back ear portions may have an interior surface and an exterior surface that correspond with the interior surface and exterior surface of the elastic inner layer. The back ear portions may include fasteners on their interior surfaces. The absorbent assembly may be attached to the exterior surface of the elastic inner layer. The absorbent assembly may include a topsheet layer, a core layer and a barrier layer. The longitudinal side edges of the elastic inner layer may form leg cuffs.
These aspects and additional aspects of the invention will be described in greater detail herein. Further, it is to be understood that both the foregoing general description and the following detailed description are exemplary and are intended to provide further explanation of the invention claimed. The accompanying drawings, that are incorporated in and constitute part of this specification, are included to illustrate and provide a further understanding of the disposable absorbent articles of the invention. Together with the description, the drawings serve to explain various aspects of the invention.
The present invention will be more fully understood and further advantages will become apparent when reference is made to the following detailed description of the invention and the accompanying drawings wherein like numerals represent like elements. The drawings are merely representative and are not intended to limit the scope of the appended claims.
The present disclosure of the invention will be expressed in terms of its various components, elements, constructions, configurations, arrangements and other features that may also be individually or collectively be referenced by the term, “aspect(s)” of the invention, or other similar terms. It is contemplated that the various forms of the disclosed invention may incorporate one or more of its various features and aspects, and that such features and aspects may be employed in any desired, operative combination thereof.
It should also 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 present invention is directed to solving problems related to providing disposable garments having close-to-the-body fit with low leakage of bodily fluids; providing disposable garments that have a barrier between the wearer's skin and bodily fluids; and providing disposable garments that have a simplified construction with a minimal number of separate components that need to be attached to the garments. Additionally, the present invention is directed to a garment having a unique combination of features that provide previously unrecognized and unexpected benefits, as will be described herein. This detailed description of the present invention will include a description of a representative disposable absorbent garment including the various components of such garments. The description of the representative disposable absorbent garment will also include a description of the features encompassed by the present invention.
Representative Disposable Absorbent Garment
The disposable absorbent garments of the present invention will be described in terms of a disposable absorbent garment that is adapted to be worn by infants about the lower torso, that is, a disposable absorbent garment that is similar to a disposable diaper. It is understood that the features of the present invention are equally adaptable for other types of disposable absorbent garments such as adult incontinence garments, training pants, disposable swim pants and feminine hygiene garments.
The elastic inner layer 20 includes an elastic material so that the elastic inner layer 20 is elastically stretchable in the lateral direction 70, the longitudinal direction 60 or both the longitudinal direction 60 and the lateral direction 70. The elastic inner layer 20 is elastically stretchable in such a way that the material is capable of substantially returning to its original length after removal of a pulling force. Various materials may be used to form the elastic inner layer 20. For example, various nonwoven materials are known that may be elastically stretchable in a machine direction (typically, the same as the longitudinal direction 60 of the garment 100) or a cross direction (which may be the same as the lateral direction 70 of the garment 100), or both. Suitable nonwoven materials include elastic nonwoven materials and laminates of nonwoven and elastic materials. The elastic inner layer 20 may also be formed from elastically stretchable film materials. Exemplary elastic films that are breathable are described in U.S. patent application Ser. No. 10/703,761 filed on Nov. 7, 2003 and titled “Microporous Breathable Elastic Films, Methods of Making Same, And Limited Use or Disposable Product Applications”, the disclosure of which is hereby incorporated by reference. Use of such breathable, elastic films may provide additional benefits for the skin health of the wearers of the garments of the invention.
Suitable elastic nonwoven materials include elastomeric materials that are treated using nonwoven manufacturing processes such as meltblowing. Suitable elastomers that may be formed into microfibers/nonwoven webs are described in U.S. Pat. No. 4,663,220 issued to Wisneski et al. on May 5, 1987 and titled “Polyolefin-Containing Extrudable Compositions and Methods for Their Formulation Into Elastomeric Products Including Microfibers”, the disclosure of which is hereby incorporated by reference. Meltblowing of KRATON copolymers (“KRATON” is a trade designation of the Shell Chemical Company) to form composite nonwoven elastic webs is described in U.S. Pat. No. 4,657,802 issued to Morman on Apr. 14, 1987 and titled “Composite Nonwoven Elastic Web”, the disclosure of which is hereby incorporated by reference.
The elastic inner layer 20 may also be formed from elastically stretchable laminate materials. U.S. Pat. No. 4,657,802 to Morman also describes composite nonwoven elastic webs, such as spunbond laminate (hereinafter “SBL”) webs. Other elastically stretchable laminate materials include NBL materials as are described in U.S. Pat. No. 5,226,992 issued on Jul. 13, 1993 to Morman, the disclosure of which is hereby incorporated by reference. Additionally, suitable breathable elastic film laminates are described in Provisional U.S. Patent Application Ser. No. 60/518,100 filed on Nov. 7, 2003 and titled “Microporous Breathable Elastic Film Laminates, Methods of Making Same, and Limited Use or Disposable Product Applications”, the disclosure of which is hereby incorporated by reference. Further, suitable elastic laminates are also described in a U.S. patent application Ser. No. ______ (serial number not assigned) filed on Dec. 22, 2003 and titled “Extensible and Stretch Laminates and Method of Making Same” having attorney reference number “K-C 20,006”, the disclosure of which is hereby incorporated by reference.
The elastic inner layer 20, suitably presents a bodyfacing, interior surface 23 that is compliant, soft feeling, and nonirritating to the wearer's skin. As shown in
The elastic inner layer 20 may define an opening 90 where the opening 90 may be located in an internal position to the perimeter 25 of the elastic inner layer 20. The elastic inner layer perimeter 25 generally corresponds to the border defined by the elastic inner layer 20. The elastic inner layer perimeter 25 may form two longitudinal side edges 55 and two lateral waist edges 35 (front waist region edge) and 45 (back waist region edge). The opening 90 may be in the form of a slit or an aperture. The size of the opening 90 may be varied depending on the size of the disposable garment 100 and the intended functions of the elastic inner layer 20. The opening 90 may be described in terms of its length relative to the total length 120 of the disposable garment 100 in the longitudinal direction 60. For example, the length 95 of the opening 90 may be from about 10% to about 90% of the total garment length 120. More specifically, the length 95 of the opening 90 may be from about 20% to about 70% of the total garment length 120. Alternatively, the length 95 of the opening 90 may be from about 30% to about 50% of the total garment length 120. As a specific example of a suitable length for an opening 90 of the invention, if the garment length 120 is 381 millimeters (mm), the length 95 of the opening 90 may range from 76 mm to 267 mm. In addition to its length 95, the opening 90 may be characterized by its location within the elastic inner layer 20. The opening 90 may be located near the lateral centerline (the midpoint of the garment's width in the lateral direction) in the crotch region 50 of the garment 100. The opening 90 may extend in the longitudinal direction 60 toward the perimeters of the front waist region 30 and the back waist region 40.
If the opening 90 is in the form of a slit, the slit may have a single straight cut or a cut with branches. For example, the opening 90 may include a slit formed in the elastic inner layer 20 at the center of the garment 100 and may further include additional “branch” slits extending away from the “tails” of the center slit. The “branch” slits may be formed at various angles to the center slit. The opening 90 may also be in the form of an aperture. The aperture, unlike the slit, may form an area in the inner elastic layer 20 through which the absorbent assembly 150 may be visible. The aperture may be characterized by its area; for example, the area of the aperture may range from about 5% to about 25% of the total surface area for the elastic inner layer 20. More specifically, the surface area of the aperture may range from about 7% to about 19% of the total surface area. Alternatively, the surface area may be from 10% to about 14% of the total surface area. A specific example of an aperture that would be suitable to form an opening 90 of the invention includes a garment 100 having a length 120 of 381 mm, front and back waist region widths of 241 mm and a crotch width of 75 mm to provide a total surface area for the elastic inner layer 20 of 3015 mm2. The area of the aperture may range from about 101 mm2 to about 508 mm2. The aperture may also be described in terms of its width. The width of the aperture may range from about 13 mm to about 101 mm. More specifically, the width of the aperture may range from about 25 mm to about 76 mm. The aperture may also be described in terms of its shape. For example, the elastic inner layer 20 may have an opening 90 in the shape of an hourglass, a rectangle or a trapezoid.
The disposable garments 100 of the invention may be constructed of an elastic inner layer 20 that is not continuous and is constructed of two or more pieces. A multiple piece construction of the elastic inner layer 20 creates the opportunity to provide garments 100 having stretch characteristics that are tailored for the various regions of the garments 100. For example, an elastic inner layer 20 may be provided that has a front waist region 30, a back waist region 40 and a crotch region 50 being elastically stretchable in different directions.
In
The topsheet layer 153 of the absorbent assembly 150 may define a bodyfacing surface that is compliant, soft feeling, and nonirritating to the wearer's skin. Further, the topsheet layer 153 may be less hydrophilic than the core layer 155. The topsheet layer 153 may be formed from a wide selection of web materials, such as porous foams, reticulated foams, apertured plastic films, natural fibers (for example, wood or cotton fibers), synthetic fibers (for example, polyester or polypropylene fibers), or a combination of natural and synthetic fibers. Various woven and nonwoven fabrics may be used for the topsheet layer 153. For example, the topsheet layer 153 may be formed of a meltblown or spunbond web of polyolefin fibers. The topsheet layer 153 may also be a bonded-carded web composed of natural and/or synthetic fibers. The topsheet layer 153 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 wettability and hydrophilicity. For example, the topsheet layer 153 may include a nonwoven, spunbond, polypropylene fabric composed of about 2.8-3.2 denier fibers formed into a web having a basis weight of about 22 grams per square meter and a density of about 0.06 gram per cubic centimeter.
The core layer 155 of the absorbent assembly 150 may suitably include a matrix of hydrophilic fibers, such as a web of cellulosic fluff, mixed with particles of a high-absorbency material commonly known as superabsorbent material. For example, the core layer 155 may include a matrix of cellulosic fluff, such as wood pulp fluff, and superabsorbent hydrogel-forming particles. The wood pulp fluff may be exchanged with synthetic, polymeric, meltblown fibers or with a combination of meltblown fibers and natural fibers. The superabsorbent particles may be substantially homogeneously mixed with the hydrophilic fibers or may be nonuniformly mixed. Alternatively, the core layer 155 may include a laminate of fibrous webs and superabsorbent material or other suitable matrix for maintaining a superabsorbent material in a localized area. The size and the absorbent capacity of core layer 155 should be compatible with the size of the interided wearer and the liquid loading imparted by the intended use of the disposable absorbent garment 100. Further, the size and the absorbent capacity of the core layer 155 can be varied to accommodate wearers ranging from infants through adults.
The high-absorbency material may be selected from natural, synthetic, and modified natural polymers and materials. The high-absorbency materials may be inorganic materials, such as silica gels, or organic compounds, such as crosslinked polymers. The term “crosslinked” refers to methods for effectively rendering normally water-soluble materials substantially water insoluble but swellable. Such methods include, for example, physical entanglement, crystalline domains, covalent bonds, ionic complexes and associations, hydrophilic associations such as hydrogen bonding, and hydrophobic associations or Van der Waals forces. Examples of synthetic, polymeric, high-absorbency materials include the alkali metal and ammonium salts of poly(acrylic acid) and poly(methacrylic acid), poly(acrylamides), poly(vinyl ethers), maleic anhydride copolymers with vinyl ethers and alpha-olefins, poly(vinyl pyrrolidone), poly(vinyl morpholinone), poly(vinyl alcohol), and mixtures and copolymers thereof. Further polymers suitable for use in the core layer 155 include natural and modified natural polymers, such as hydrolyzed acrylonitrile-grafted starch, acrylic acid grafted starch, methyl cellulose, carboxymethyl cellulose, hydroxypropyl cellulose, and the natural gums, such as alginates, xanthan gum, locust bean gum, and the like. Mixtures of natural and wholly or partially synthetic absorbent polymers may also be useful. The high absorbency material may be in any of a wide variety of geometric forms. As a general rule, the high absorbency material is in the form of discrete particles. However, the high absorbency material may also be in the form of fibers, flakes, rods, spheres, needles, or the like. In general, the high absorbency material is present in the core layer 155 in an amount of from about 5 to about 90 percent by weight, desirably in an amount of at least about 30 percent by weight, and even more desirably in an amount of at least about 50 percent by weight based on a total weight of the core layer 155. For example, in a particular aspect, the core layer 155 may include a laminate which includes at least about 50 percent by weight and desirably at least about 70 percent by weight of high-absorbency material overwrapped by a fibrous web or other suitable material for maintaining the high-absorbency material in a localized area. An example of high-absorbency material suitable for use in the present invention is DRYTECH 2035 polymer available from Dow Chemical, a business having offices in Midland, Mich. Other suitable superabsorbents may include FAVOR SXM 880 polymer obtained from Stockhausen, a business having offices in Greensboro, N.C.
The barrier layer may 157 be formed from a thin plastic film or other flexible liquid-impermeable material. For example, the barrier layer 157 may be formed from a polyethylene film having a thickness of from about 0.013 millimeter (0.5 mil) to about 0.051 millimeter (2.0 mils). The barrier layer 157 may also be formed from a polyolefin film having a nonwoven web laminated to the exterior surface thereof, such as a spunbond web of polyolefin fibers. For example, a stretch-thinned polypropylene film having a thickness of about 0.015 millimeter (0.6 mil) may be thermally laminated thereto a spunbond web of polypropylene fibers. The polypropylene fibers may have a fiber diameter of about 15 to 20 microns, which nonwoven web has a basis weight of about 17 grams per square meter (0.5 ounce per square yard). The barrier layer 157 may include bicomponent fibers such as polyethylene/polypropylene bicomponent fibers. The barrier layer 157 may also include a vapor permeable non-woven facing layer laminated to a micro-porous film to impart “breathability” to the barrier layer. Suitable “breathable” barrier layer 157 materials are described in U.S. Pat. No. 5,695,868 issued Dec. 9, 1997 to McCormack et al. and U.S. Pat. No. 5,843,056 issued Dec. 1, 1998 to Good et al., the descriptions of which are hereby incorporated by reference.
The absorbent assembly 150 may be attached to the exterior surface 27 of the elastic inner layer 20.
The absorbent assembly 150 may be constructed in such a way that when it is attached to the elastic inner layer 20, leg cuffs 280 and containment flaps 290 are formed. The leg cuffs 280 may be formed by the portions of the elastic inner layer 20 that extend laterally outward from the attachment regions 270. The containment flaps 290 may be formed by the portions of the elastic inner layer 20 that extend laterally inward from the attachment region 270. The presence of the opening 90 approximately divides the elastic inner layer 20 into two halves around a front body line 260 of the garment 100. The elastic inner layer 20 may be divided into a right inner elastic layer region 300 and a left inner elastic layer region 310. The absorbent assembly is shown as being attached to the right inner elastic layer region 300 and the left inner elastic layer region 310 by the attachment regions 270. The attachment regions 270 may run the full length 97 of the absorbent assembly 150 (length 97 is shown in
The lateral width of the attachment regions 270 may range from about 2 mm (“mm”=millimeters) to about 60 mm. More desirably, the width of the attachment regions 270 may be from about 3 mm to about 40 mm and even more desirably, from about 4 mm to about 20 mm. While the attachment regions 270 may extend the full length 97 of the absorbent assembly 150, it may desirable for the attachment regions 270 to have a length of from about 100 mm to about 390 mm, depending on the size of the absorbent assembly 150 and the overall size of the garment 100. More desirably, the attachment regions 270 have a length of from about 150 mm to about 350 mm and even more desirably, a length of from about 200 mm to about 300 mm. The length 97 of the absorbent assembly 150 is desirably selected so that the entire length 95 of the opening 90 is covered by the absorbent assembly 150 when the absorbent assembly is attached to the exterior surface 27 of the elastic inner layer 20. In addition to the attachment regions 270 shown in
In a further aspect of the present invention, leg cuffs and barrier cuffs may alternatively be formed by lateral extensions of the topsheet layer 153 and the barrier layer 157. For example, in
The disposable absorbent garments 100 of the invention may include mechanical fasteners 130 and 140 for attaching the front waist region 30 and the back waist region 40 together. The material forming the mechanical fasteners 130 and 140 may be integral with the elastic inner layer 20 (and the outer layer 80 when the garment 100 includes an outer layer 80) or the material may be provided on separate portions (e.g. front ear portion 33 and back ear portion 43) that are attached to the longitudinal side edges 55 of the garments 100 in the waist regions. In
Most commercially-available diapers include a fastener attached to the back waist region in such a way that the fastener may engage the front waist region of the diaper. This type of fastening system may result in the front waist region drooping or sagging during wear. The combination of mechanical fasteners 130 and 140 and how they are integrated with the overall design of the disposable absorbent garments 100 of the invention prevents such a loss of fit. As will be described in more detail herein, the front waist region fastener 130 is positioned on the longitudinal side edge 55 of the garment 100 in such a way so as to be capable of extending beyond the garment seam line 160 to engage the elastic inner layer 20. The garment seam line 160 is located behind the center line of the side of the wearer. By positioning the front waist region fastener 130 beyond the garment side seam line 160, the fastener 130 is moved out of the highly compressed area in the front waist region 30 of the garment 100. There are at least five features of the location of the front waist region fastener 130 that affect the quality of garment fit and fastener engagement during wear: (1) distance of the front waist region fastener 130 from an “extended crotch line” 170; (2) the angle “α” of the crotch line 170 at the narrowest crotch width 57 to the bottom of the front waist region fastener 130; (3) the narrowest crotch width 57 (distance from one leg edge to the other at the narrowest portion of the crotch region 50); (4) the front center panel length 190 (distance from the narrowest crotch width 57 to the front waist edge 35 of the garment 100); and (5) the front waist region fastener length 200. These features are representatively illustrated in
The width 57 at the narrowest portion of the crotch region 50 also impacts garment fit and fastener engagement. For example, as the width 57 at the narrowest portion is increased, the crotch-to-fastener angle α from the crotch line 170 to the bottom 225 of the front waist region fastener 130 decreases. Therefore, it is desirable that the disposable absorbent garments of the invention have a width 57 at the narrowest portion of equal to or less than about 4 inches. A width 57 at the narrowest portion of equal to or less than 3.5 inches is more desirable and a width 57 at the narrowest portion of equal to or less than 3.0 inches is even more desirable. The narrow width 57 is desirable regardless of the size of the intended wearer of the disposable absorbent garment 100. That is, a disposable absorbent garment 100 having a width 57 at the narrowest portion of 3.0 inches will provide sufficient coverage regardless of whether the wearer of the garment 100 is an infant or an adult. Another feature that impacts garment fit and the quality of fastener engagement is the front center panel length 190. Although the front center panel length 190 illustrated in
Another feature of the location of the front waist region fastener 130 that may impact garment 100 fit and fastener engagement is the length 200 of the front waist region fastener 130. When the length 200 of the front waist region fastener 130 is decreased, the crotch-to-fastener angle α decreases. Therefore, it is desirable that the length 200 of the front waist region fastener 130 be equal to or less than the front center panel length 190. More desirably, the length 200 of the front waist region fastener 130 is equal to or less than 75% of the front center panel length 190. Even more desirably, the length 200 of the front waist region fastener 130 is equal to or less than 50% of the front center panel length 190. Various combinations of the features related to the position of the front waist region fastener 130 may be identified to improve the overall fit and fastener engagement of the disposable garments 100 of the invention.
In order to provide a unitary feel and appearance, the garments 100 of the invention may include an outer layer 80 that overlays the absorbent assembly 150 and the exterior surface 27 of the elastic inner layer 20. The outer layer 80 (visible in
Just as the size of the opening 90 may be related to the elastic inner layer 20 in terms of surface area, the size of the elastic inner layer 20 relative to the outer layer 80 may be considered in terms of surface area. For example, the elastic inner layer 20 may have a smaller surface area than the outer layer 80. As surface area is determined by length and width, the outer layer 80 may have a greater length in the longitudinal direction 60 of the disposable garment 100 than the elastic inner layer 20. The length of the elastic inner layer 20 may be determined when the elastic inner layer 20 is in a relaxed and retracted state. The outer layer 80 may also have a width in the lateral direction 70 that is greater than the width of the elastic inner layer 20 in the lateral direction 70. When the garment 100 is constructed so that the elastic inner layer 20 is smaller than the outer layer 80 in its relaxed, retracted state, the elastic inner layer 20 provides a snug fit against the body of the wearer of the garment 100 while the larger, outer layer 80 provides area and volume for containment.
There are several approaches for providing a garment 100 having an elastic inner layer 20 that is smaller than the outer layer 80. For example, the elastic inner layer 20 may be stretched or elongated during manufacture and then attached to an outer layer 80 formed of non-stretchable material. The layers may be attached to each other using known bonding techniques such as adhesive, ultrasonic or thermal bonding. The elastic inner layer perimeter 25 may be attached to the outer layer 80. The elastic inner layer perimeter 25 may be “matched” up with the outer layer perimeter or the elastic inner layer perimeter 25 may be attached to the outer layer 80 within the outer layer perimeter. After the elastic inner layer 20 and the outer layer 80 are bonded together, the elongated elastic inner layer 20 retracts and gathers the outer layer 80. As a result, the gathered outer layer 80 may appear blousy.
As described herein, the elastic inner layer 20 may be provided by a material that has multi-directional stretch. When the elastic inner layer 20 is stretched in more than one direction prior to bonding with the outer layer 80, the resulting garment 100 has an outer layer 80 that has been gathered in more than one direction. A gathered perimeter may be formed by the elongated elastic inner layer 20 being bonded to the non-stretchable outer layer 80. This construction provides the advantage of an outer layer 80 that may be gathered in any shape or surface area needed for a particular disposable garment design. This construction also provides the ability to form a garment 100 having areas of curvature (e.g. highly curved gatherings) without the need to incorporate individual, highly-curved elastic components.
The degree to which the outer layer 80 is gathered is related to the elongation and stretch direction of the elastic inner layer 20. When the elastic inner layer perimeter 25 is bonded to the outer layer 80, the direction of stretch of the elastic inner layer 20 will create gathers. The elastic inner layer 20 may be constructed of elastic materials that are capable of providing a range of tension and percent elongation. For example, the material may have percent elongation of from about 10% to about 400%. More specifically, the percent elongation may range from about 30% to about 200% or from about 50% to about 150%. The percent elongation may be different in different directions of stretch. For example, a suitable elastic material for constructing the elastic inner layer 20 may have a percent elongation of 50% in the cross-direction (or lateral direction 70) and a percent elongation of 100% in the machine direction (or longitudinal direction 60). Suitable elastic materials may also be characterized by the force to elongate the material and the retractive force that the material provides during use. For example, the force to elongate may range from about 100 grams to about 1000 grams (based on elongating a 7.62 centimeter (cm) wide sample to 50% elongation). More specifically, the force to elongate may range from about 200 grams to about 800 grams or from about 400 grams to about 600 grams. The retractive force provided during use may be similar to the force to elongate. These forces to elongate and forces to retract of the elastic inner layer 20 are suitable whether the garment 100 includes an outer layer 80 or not.
Another approach for providing a garment 100 having an elastic inner layer 20 that is smaller than the outer layer 80 is to provide an outer layer 80 formed from an extensible material. The extensible material may be capable of extending in a machine direction (e.g. longitudinal direction 60) and/or a cross-direction (e.g. lateral direction 70). Extensible materials are capable of increasing their length in a given direction and therefore, their area, with minimal force. The percent extensibility of a material may be defined as the difference between the extended surface area and the initial surface area divided by the initial surface area; the quotient then being multiplied by 100. With a multi-directional extensible material, the material may increase its length in multiple directions and therefore, increase the surface area of the outer layer 80 to a degree related to the percent extensibility of the material. For example, the percent extensibility of a suitable material may range from about 10% to about 150%. More specifically, the percent extensibility may range from about 20% to about 80% or from about 30% to about 50%. Suitable materials for forming an extensible outer layer 80 are described in U.S. Pat. No. 6,610,383 entitled “Transversely Extensible and Retractable Necked Laminate of Non-Elastic Sheet Layers” which issued on Aug. 26, 2003 to Morman et al. and U.S. Pat. No. 6,632,212 entitled “Breathable Laminate Permanently Conformable to the Contours of A Wearer” which issued on Oct. 14, 2003 to Morman et al., the disclosures of which are hereby incorporated by reference. An advantage of this approach is that the elastic inner layer 20 does not have to be elongated prior to bonding to the outer layer 80. Another difference is that bonded region may not have a gathered appearance prior to the garment 100 being worn. When the garment 100 is stretched during donning, the outer layer 80 formed with an extensible material will elongate, thereby increasing its area and creating a gathered appearance where the elastic inner layer perimeter 25 is bonded. This aspect is representatively illustrated in
Yet another approach to providing a garment 100 having an elastic inner layer 20 that is smaller than the outer layer 80 is to use an outer layer 80 that has a three-dimensional shape. As with the previous approach, an advantage of this approach is that the elastic inner layer 20 does not have to be elongated prior to bonding with the outer layer 80. An example of an outer layer 80 having a three-dimensional shape is to provide an outer layer 80 that has one or more pleats. The pleats permit an outer layer 80 having a length that is greater than the length of an attached elastic inner layer 20 in the cross-direction of the garment 100. While these approaches may be used to provide an outer layer 80 having a greater area than the relaxed area of the elastic inner layer 20, the garments 100 of the invention may also include an outer layer 80 that does not completely overlay the entire area of the elastic inner layer 20. For example, the outer layer 80 may only overlay the absorbent assembly 150.
As already described herein, the disposable garments 100 of the invention may be constructed in such a way that the elastic inner layer perimeter 25 is bonded to an outer layer 80. The elastic inner layer perimeter 25 may be bonded by using bonding techniques such as adhesive, ultrasonic or thermal bonds. In one aspect, the elastic inner layer perimeter 25 is bonded to the perimeter of the outer layer. The perimeter bonding of the components permits the elastic inner layer 20 to fully stretch. Additionally, as already described, when the elastic inner layer 20 is bonded to an outer layer 80 formed of a non-stretchable material, the perimeter bonding creates the visual appearance of gathered waist and leg regions without the addition of separate elastic components, such as waistbands and leg elastics. Elimination of the need to incorporate separate elastic components results in a garment 100 that lies flat. This feature is significant when the garment 100 is in the form of an infant diaper; diapers that lie flat are easier to apply to infants and toddlers than diapers that want to curl closed. Additionally, the perimeter bonding provides an elastic inner layer retraction value that is greater than an outer layer retraction value. Desirably, the elastic inner layer retraction value is greater than the outer layer retraction value regardless of the type of material from which the outer layer 80 is made. If the outer layer 80 is made from a non-stretchable material, the elastic inner layer retraction value will be inherently greater (because the material of the outer layer 80 has no significant retraction). If the outer layer 80 is made from an extensible material or an elastic material, the retractive force of that material is desirably less than the retractive force of the material used to form the elastic inner layer 20.
The perimeter bonding that is used to form garments 100 of the invention may have several characteristics. For example, one characteristic is the percent of the perimeter of the elastic inner layer 20 that is bonded to the outer layer 80. In
The elastic inner layer perimeter 25 and the outer layer 80 may be bonded together using various techniques. As already described, the elastic inner layer perimeter 25 may be ultrasonically bonded to the outer layer 80. The shape of the bonding pattern may include a pattern anvil roll that takes the shape of the perimeter being bonded. An advantage of this method is that the bond pattern may also include a raised edge that permits the anvil roll to bond the two or more layers of materials, but also trims excess material that extends outward beyond the perimeter bond. The perimeter of the garment 100 may also be bonded with the use of pressure and heat. The shape of the bond pattern would be a pattern anvil roll and when the composite is run through the nip, the composite would be pressure bonded to the shape of the bond pattern. Additionally, the perimeter of the garment 100 may also be bonded with the use of adhesive. Desirably, the adhesive may be applied in a pattern that outlines the perimeter of the garment 100. The adhesives may be of a pressure-sensitive type or of a type that may be applied as a print adhesive.
The close-to-the-body fit and simplified construction of the disposable absorbent garments 100 of the invention may be provided in part, by the combination of the elastic inner layer 20 and the attachment of the absorbent assembly 150. The capacity of the disposable garments of the invention to contain bodily wastes may be provided by the combination of the opening 90 together with the manner in which the absorbent assembly 150 is attached to the elastic inner layer 20. When these features are combined, the disposable garments 100 of the invention unexpectedly provide excellent fit, minimal leakage and a simple garment construction that does not require the attachment of many individual components. Further, the elastic inner layer 20 separates the wearer's skin from the wastes contained by the absorbent assembly 150. By virtue of the absorbent assembly 150 being attached to the elastic inner layer 20 in the attachment regions 270 and other features, the garments 100 have a “light” or simplified “framework” or construction. The material properties of the elastic inner layer 20 and the absence of the attachment of separate components in the front waist region 30 and the back waist region 40 provide garments 100 having a flexible waist closure or seal. Given the trend toward more complex disposable absorbent garments having more features and more components, the effectiveness of the garments 100 of the invention is unexpected.
While the disposable absorbent garments of the invention have been described in detail with respect to specific aspects thereof, it will be appreciated that those skilled in the art, upon attaining an understanding of the foregoing, may readily conceive of alterations to, variations of and equivalents to these garments. Accordingly, the scope of the present invention should be assessed as that of the appended claims and any equivalents thereto.
