Patent Application
20160193091
The present invention relates generally to disposable absorbent products such as infant diapers, adult incontinence briefs, pull-up underwear, bladder control pads, bed pads.
Absorbent articles, such as baby diapers, training pants, adult incontinence products and other such absorbent products include a topsheet that is closest to the wearer, an outer, moisture-impermeable backsheet, and an absorbent core. Disposable absorbent products have met with widespread acceptance in the marketplace for a variety of applications, including infant and adult incontinence care, in view of the manner in which such products can provide effective and convenient liquid absorption and retention while maintaining the comfort of the wearer. Softness and ability to provide comfort while product is being worn by a wearer is paramount to the acceptance of the product. Perception of the softness by a user or caregiver taking the product out of its packaging is equally important. If a caregiver or user senses the hard spots and superabsorbent polymer (SAP) particles through the outer cover, could lead to negative perception of the product and its efficacy.
Softness of the nonwoven backsheet depends on visual, auditory, and tactile signals. The tactile softness signal is perceived most during use and when the product is first touched by the user. The tactile signal of absorbent articles is mostly perceived via an outer cover that has the nonwoven backsheet and topsheet. The tactile softness signal exhibited by the outer cover depends on the flexibility of nonwoven fibers, pliability, surface friction characteristics, loose fibers or free fiber ends, amount of fibers, and the cushiness of these elements.
Significant efforts have been made to improve the tactile signals when handling absorbent products. Conventional means of improving tactile signals include embossing with soft calender patterns, an increase in basis weight, increase in fiber density to increase loft, alterations in resin chemistry, adding soft additives, slip agents, bi-component fiber technology, hydro entangling, and hydro engorging. These approaches are unfavorable because they drive up raw material costs. Yet another limitation is that soft calendar patterns, bi-component fiber nonwoven, additives, spin finishes, and slip agents all have an adverse effect of decreasing mechanical properties, such as tensile strength, of the absorbent article.
Prior methods of providing a soft back sheet and poly film laminate outercover include the multiple limitations. First, there is a constant desire to run production lines faster in order to reduce manufacturing costs. However, when production line speeds increase, a probability of having uneven regions per unit area in an absorbent core of the product also increases. When these uneven regions are compressed for packaging, hard spots are formed. Hard spots may appear more pronounced in particular when using relatively high production speeds and for relatively thin absorbent cores.
Secondly, there is constant desire to go towards thinner and thinner outercover laminates to achieve desired cost structure. The relatively thin backsheet and poly films allow for hard spots and SAP particles to protrude and poke easily through the poly film/backsheet laminate.
Furthermore, there is a trend towards thinner absorbent products has been driven by a desire for absorbent products to take up less space for transport and storage. Thus, absorbent products are packaged by compressing the absorbent product between compression rolls to reduce its thickness. This increased compression levels can lead to hard spots that protrude and poke through the poly film/backsheet laminate, thereby adversely affecting the softness signal. Another limitation is that a reduction in the compression in package and/or increasing the package size will adversely affect the cost strategy.
Hard-spots can be felt by a user are caregiver of the absorbent product both before use, e.g., taking product out of bags, and in use. Being relatively stiff, the hard-spots may be perceived by a user as causing a less comfortable and less efficient product. These hard spots felt by user could lead to significant negative impact on the overall softness and comfort in case of bed pads and adult incontinent products and can lead to bed sore and rashes.
This disclose includes embodiments of disposable absorbent articles and methods of making disposable absorbent articles that comprise: an absorbent structure; and a layer of cushion material configured to reduce user perception of hardness or hard spots in the absorbent structure.
Some embodiments of the present disposable absorbent articles comprise: an absorbent structure; a nonwoven fabric; and a layer of cushion material disposed between the nonwoven fabric and the absorbent structure, the layer of cushion material defining a plurality of air pockets; where the layer of cushion material and the nonwoven fabric form a composite having an uncompressed thickness of between 0.4 millimeters and 8.5 millimeters, and a thickness of between 0.1 millimeters and 5.0 millimeters when subjected to a compressive force of 500 grams. In some embodiments, the layer of cushion material is resilient.
Some embodiments of the present articles further comprise: a film; where the film and the layer of cushion material are both disposed between the nonwoven fabric and the absorbent structure, and where the composite includes the film. In some embodiments, the layer of cushion material is configured to minimize a tactile signal of the absorbent structure through the nonwoven fabric.
In some embodiments of the present articles, the composite includes a z-direction deformation in the range of about 0.12 millimeters to 2.5 millimeters under a compressive force in the range of 50 to 500 grams.
In some embodiments of the present articles, the absorbent structure includes a superabsorbent polymeric (SAP) particulate material. In some embodiments, the absorbent structure includes cellulose fiber.
In some embodiments of the present articles, the layer of cushion material includes a poly film defining the plurality of air pockets. In some embodiments, the poly film is at least partially dimpled, pleated, or embossed, and the poly film is configured to exhibit a deformation in the range of 0.15 mm to 0.3 mm under a compression force in the range of 50 grams to 500 grams. In some embodiments, the layer of cushion material includes a plurality of embossed poly films defining the plurality of air pockets, the plurality of embossed poly films being laminated to each other adhesively, thermally, by co-extrusion, ultrasonically, or any combination thereof.
Some embodiments of the present articles further comprise: a spray or signature in an adhesive pattern with at least one spacing of 10 mm or larger such that the composite is configured to exhibit a deformation in the range of 0.3 mm or more under a compressive force in the range of 50 grams to 500 grams.
In some embodiments of the present articles, the layer of cushion material includes a spunlace nonwoven defining the plurality of air pockets such that the composite is configured to exhibit a deformation in the range of 0.18 mm to 1.2 mm under a compressive force in the range of 50 grams to 500 grams. In some embodiments, the spunlace nonwoven include fibers with 60% or more of a PET fiber blend.
In some embodiments of the present articles, the layer of cushion material includes a spunlace nonwoven having an embossed pattern facing away from the absorbent structure to define the plurality of air pockets.
In some embodiments of the present articles, the layer of cushion material includes a carded through-air bonded (TAB) nonwoven defining the plurality of air pockets and covering at least the absorbent structure, such that the composite is configured to exhibit a deformation in the range of 0.4 mm or more under a compressive force in the range of 50 grams to 500 grams. In some embodiments, a basis weight of the carded TAB nonwoven is 22 gsm or higher with a fiber composition including any combination of the following: polyester, PP, bi-component fibers of PP-PE, PET-PE, PET/co-PET, PP-PET, cotton, bleached cotton, unbleached cotton, jute, ramie, and flax.
In some embodiments of the present articles, the layer of cushion material includes at least one material selected from the group consisting of: closed-cell polymeric foam, open-cell polymeric foam, bubble wrap, and embossed paper. In some embodiments, at least some of the plurality of air pockets include a shape selected from the group consisting of: honeycomb, square, circular, or randomly varied.
Some embodiments of the present methods (e.g., of assembling an absorbent article) comprise: joining a layer of cushion material and a nonwoven fabric to form a cushion structure, the layer of cushion material including a plurality of air pockets; and positioning the cushion structure on an absorbent structure; where the cushion structure has an uncompressed thickness of between 0.4 millimeters and 8.5 millimeters, and a thickness of between 0.1 millimeters and 5.0 millimeters when subjected to a compressive force of 500 grams.
Some embodiments of the present methods further comprise: joining a bonding fabric to an outwardly facing surface of the cushion structure.
In some embodiments of the present methods, the layer of cushion material is configured to minimize a tactile signal of the absorbent structure on a side of the layer of cushion material opposite the absorbent structure.
In some embodiments of the present methods, the absorbent structure includes a superabsorbent polymeric (SAP) particulate material.
In some embodiments of the present methods, joining the layer of cushion material and the nonwoven fabric includes at least one joining process selected from the group consisting of: thermal bonding, ultrasonic bonding, adhesive lamination, pressure lamination, and co-extrusion.
In some embodiments of the present methods, the layer of cushion material includes at least one material selected from the group consisting of: closed-cell polymeric foam, open-cell polymeric foam, bubble wrap, and embossed paper.
In some embodiments of the present methods, the layer of cushion material includes a carded and through-air bonded nonwoven layer with a basis weight of 20 gsm or higher. Some embodiments further comprise: bonding a liquid-impervious polymeric film to the cushion structure when the cushion structure includes at least one of the open-cell polymeric foam and the embossed paper.
In some embodiments of the present methods, positioning the layer of cushion material includes completely covering the absorbent article with the layer of cushion material.
Some embodiments of the present disposable articles comprise: an absorbent structure; and a layer of cushion material coupled to the absorbent structure such that the layer of cushion material defines a backsheet of the absorbent article, the layer of cushion material defining a plurality of air pockets; where the layer of cushion material has an uncompressed thickness of between 0.4 millimeters and 8.5 millimeters, and a thickness of between 0.1 millimeters and 5.0 millimeters when subjected to a compressive force of 500 grams; and where the layer of cushion material includes at least one material selected from the group consisting of: closed-cell polymeric foam, open-cell polymeric foam, bubble wrap, and embossed paper.
“Hard spots,” with respect to absorbent hygiene products, are described as local regions in a core being more compact and stiffer than an overall core.
“Superabsorbent” or “superabsorbent material” or “SAP” refers to a water-swellable, water-insoluble organic or inorganic material capable, under the most favorable conditions, of absorbing at least about 15 times its weight and, more desirably, at least about 30 times its weight in an aqueous solution containing 0.9 weight percent sodium chloride. The SAP materials can be natural, synthetic and modified natural polymers and materials. In addition, the SAP materials can be inorganic materials, such as silica gels, or organic compounds such as cross-linked polymers.
“Disposable” refers to articles which are designed to be discarded after a limited use rather than being laundered or otherwise restored for reuse.
“Absorbent core” means a structure typically disposed between a topsheet and backsheet of an absorbent article and containing materials which absorb in absorbent article. The absorbent core may also include a cover layer or envelope material. The cover layer or envelope may comprise; nonwovens, SAP, cellulosic or non-cellulosic materials, films, fibers or substrate made of any one two or all of these combination materials.
“Layer” when used in the singular can have the dual meaning of a single element or a plurality of elements.
“Nonwoven” fabrics, according to an INDA definition, are broadly defined as sheet or web structures bonded together by entangling fiber or filaments (and by perforating films) mechanically, thermally, or chemically. They are flat, porous sheets that are made directly from separate fibers or from molten plastic or plastic film. They are not made by weaving or knitting and do not require converting the fibers to yarn. The basis weight of nonwoven fabrics is usually expressed as gsm or grams per square meter.
“Nonwoven backsheet” is a backing substrate layer in the outer cover. The nonwoven backsheet is most often a nonwoven layer facing away from the wearer. “Film” means a membrane-like layer of material formed of one or more polymers, which does not have a form consisting predominately of a web-like structure of fibers and/or other fibers. Film referred to in this disclosure as “poly film” is a film that is disposed in the outer cover laminate. The poly film can be breathable film or non-breathable.
The term “breathable film,” “breathable laminate” or “breathable outer cover material” refers to a film, laminate, or outer cover material having a water vapor transmission rate (“WVTR”) of at least about 300 grams/m224 hours. Breathable materials typically rely on molecular diffusion of vapor, and are substantially liquid impermeable.
“Liquid impermeable,” when used in describing a layer or multi-layer laminate, means that a liquid, such as urine, will not pass through the layer or laminate, under ordinary use conditions, in a direction generally perpendicular to the plane of the layer or laminate at the point of liquid contact.
“Bubble wrap” is a pliable transparent plastic material commonly used for packing fragile items. Regularly spaced, protruding air-filled hemispheres (bubbles) provide cushioning for fragile items.
“Foam material” refers to a material made with the aid of a foaming process. The term “open cell foam material” refers to a foam layer whose cells interconnect, or otherwise create voids from one surface of the layer to the opposite surface. The term “closed cell foam material” refers to a foam layer whose cells are not substantially interconnected.
“Lamination” is the technique of manufacturing a material in multiple layers, so that the composite material has benefits of all the encompassing layers; improved strength, stability, sound insulation, appearance or other properties. A laminate is a permanently assembled object by heat, pressure, welding, or adhesives.
“Bonded” refers to the joining, adhering, connecting, attaching, 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.
“Deformation,” with regard to the substrates mentioned herein, refers to the percent change in length that occurs while the material is stressed or compressed.
“Machine direction” (MD), with respect to the making of a nonwoven web material, refers to the direction along the material or laminate substantially parallel to the direction of forward travel of the material or laminate through the manufacturing line in which the material or laminate is manufactured. “Cross direction” (CD), with respect to the making of a nonwoven or laminate, refers to the direction along the material substantially perpendicular to the direction of forward travel of the material through the manufacturing line in which the material and/or article is manufactured. “Z-direction,” means perpendicular to plane approximated by the web along machine and cross direction.
“Asymmetric embossed” is an embossed paper towel in which each layer of the papers has its own embossing pattern such that when the layers of paper are combined together by bonding, they have significant lofty and cushiness due to asymmetry and embossing.
“Aero-soft materials” refers to the soft materials that have ability to incorporate or entrap or hold on to air and exhibits cushiness or softness.
The term “coupled” is defined as connected, although not necessarily directly, and not necessarily mechanically. The terms “a” and “an” are defined as one or more unless this disclosure explicitly requires otherwise.
Further, a device or system that is configured in a certain way is configured in at least that way, but it can also be configured in other ways than those specifically described.
The terms “comprise” (and any form of comprise, such as “comprises” and “comprising”), “have” (and any form of have, such as “has” and “having”), “include” (and any form of include, such as “includes” and “including”), and “contain” (and any form of contain, such as “contains” and “containing”) are open-ended linking verbs. As a result, an apparatus that “comprises,” “has,” “includes,” or “contains” one or more elements possesses those one or more elements, but is not limited to possessing only those elements. Likewise, a method that “comprises,” “has,” “includes,” or “contains” one or more steps possesses those one or more steps, but is not limited to possessing only those one or more steps.
Any embodiment of any of the apparatuses, systems, and methods can consist of or consist essentially of—rather than comprise/include/contain/have—any of the described steps, elements, and/or features. Thus, in any of the claims, the term “consisting of” or “consisting essentially of” can be substituted for any of the open-ended linking verbs recited above, in order to change the scope of a given claim from what it would otherwise be using the open-ended linking verb.
The feature or features of one embodiment may be applied to other embodiments, even though not described or illustrated, unless expressly prohibited by this disclosure or the nature of the embodiments.
Some details associated with the embodiments described above and others are described below.
The following drawings illustrate by way of example and not limitation. For the sake of brevity and clarity, every feature of a given structure is not always labeled in every figure in which that structure appears. Identical reference numbers do not necessarily indicate an identical structure. Rather, the same reference number may be used to indicate a similar feature or a feature with similar functionality, as may non-identical reference numbers. Views in the figures are drawn to scale (unless otherwise noted), meaning the sizes of the depicted elements are accurate relative to each other for at least the embodiment in the view.
Referring now to the drawings, and more particularly to
In some embodiments, air pockets 18 are configured to protrude in a z-direction out of a general plane of backsheet 22 and away from a wearer. In this configuration, air pockets 18 are configured to face away from the wearer such that the dips and hills between air pockets 18 can be felt through backsheet 22 by the user handling absorbent article 10. For example, air pockets 18 create a layer of springy loft which enhances a softness felt by the user handling absorbent article 10. By blocking irritating signals caused by hard spot and/or SAP protrusions, the user feels a tactile soft cushiness signal when the absorbent article 10 is in use or when the absorbent article 10 is being removed from packaging.
Air pocket height 30 and length 34 can be selected such that air pockets 18 will not hinder compression of absorbent article 10 during processing or packaging. For example, air pocket height 30 and length 34 are selected such that poly film 14 withstands packaging compression and that when the user takes absorbent article 10 out of its packaging, between 70% and 95% such as 80% of air pocket height 30, softness, and/or cushioning effect is regained.
Layer of cushion material 38 may include any appropriate material configured to have a higher compressibility than absorbent structure 26. Layer of cushion material 38 includes the plurality of air pockets 18. Air pockets 18 are configured to increase comfort, and reduce bed sores and rashes for the user.
In some embodiments, air pockets 18 are formed on a flat surface, such as a film. In some embodiments, air pockets 18 are laminated between two films. Air pockets 18 may be coupled end to end. Air pockets 18 may be configured such that they face away from the wearer of absorbent article 10. For example, air pockets 18 are disposed on an outer side of absorbent article 10, away from the wearer.
In other embodiments, layer of cushion material 38 includes a foam film 62. Foam film 62 may include open-cell structures 62a or closed-cell structures 62b, as shown in
In other embodiments, layer of cushion material 38 includes a poly film 70 having embossing thereon such that when poly film 70 is laminated to backsheet 22, poly film 70 and backsheet 22 form air pockets 18 therebetween. As shown, the poly film 70 may be directly laminated to the backsheet 22, as shown in
In some embodiments, layer of cushion material 38 includes bubble wrap 74 having air pockets 18. In one example, bubble wrap 74 is laminated with poly film 14 and joined with backsheet 22, as shown in
In other embodiments, layer of cushion material 38 includes a polyfilm with micro pleats.
In other embodiments, layer of cushion material 38 includes spunlace nonwovens and spunlace nonwoven laminates between poly film 14 and backsheet 22. For example, the spunlace nonwovens may include a PET fiber blend, which may be commercially obtained from Spuntech, Jacob Holmes, PGI Nonwovens, or Fitesa.
In other embodiments, layer of cushion material 38 includes carded and through air bonded nonwovens. Such carded and through air bonded nonwoven can be commercially obtained from companies such as Texsus, Shalag, Freudenberg, PGI Nonwovens, Fitesa, or Berry Plastics.
Lamination may be provided using adhesive lamination (ADH). Third party laminators, such as Web Industries and Tufco, may also provide lamination services suitable to join layer of cushion material 38, poly film 14, and/or backsheet 22. In some embodiments, adhesive patterns 78 used in lamination may form a plurality of air pockets 18 between poly film 14 and absorbent structure 26. For example, air pockets 18 may be formed by varying a distance 82 between a spray 78a or signature 78b adhesive pattern used to laminate poly film 14 and backsheet 22. Distances 82 in adhesive patterns 78 are shown in
In some embodiments, poly film 14 having the plurality of air pockets 18 is joined to backsheet 22 by thermal bonding, co-extrusion lamination and/or adhesive lamination. As a result, a volume between air pockets 18 may not be bonded to backsheet 22. The volume between air pockets 18 will not restrict backsheet 22. The volume serves as a hinge point and provides additional drape to poly film 14/backsheet 22 laminate. In some embodiments, the volume between air pockets 18 appears loftier and, as a result, air pockets 18 appear more pronounced and visually clearly defined to the user.
In some embodiments, layer of cushion material 38 covers an entire width of absorbent article 10 as shown in
A compression test may determine the cushion or tactile cushion softness exhibited by a sample laminate of each embodiment described herein.
The table below displays measurements of a pre-load height of the sample material (HT-PL) and a height under an applied compression load of 500 grams (HT-LD). When a caregiver or user of absorbent article perceives the tactile cushiness of laminate sample they typically use the end of an index finger, hyponychium, and apply a force in the range of 50 grams to maximum of 500 grams. The present testing therefore examined extension and height change in samples for force in the range of 50 grams to 500 grams.
As shown in the table above, foam films both 1/32″ and 1/16″ thick exhibited more cushioning than the DPC poly film and other poly films that are found in commercially available diaper products in market. DPC poly film undergoes a thickness change of 0.02 millimeters, which is negligible when compared to a thickness change exhibited by an aero-soft laminate, e.g., Lamifoam film 1/32-nonwoven laminate, which exhibited a thickness change of approximately 0.4 millimeters. Under a force of 50 grams to 500 grams, the DPC poly film and poly film found in commercially available absorbent products in market place exhibited a deformation of 0.1 millimeters or less, whereas, the foam film or soft materials have 0.1 millimeters or greater deformation or extension along an x-axis. Compression test data showed that laminate exhibited cushiness when it experienced more deformation along the x-axis, as shown by the dotted line box in
In paper towels, two layers of paper are combined with a thin layer of adhesive and embossed to form many tiny air pockets that rapidly attract moisture. Diamond shapes are pressed into the paper to give it a quilted pattern that holds water. The Charmin paper towel had lower initial thickness before load compared to Bounty. The number of layers, bonding method, embossing structure determines the extent of cushiness of the paper towel.
Various asymmetrically embossed paper towels can be used to increase the tactile and cushiness of outer laminates. Based on how the embossed paper towels are manufactured, their basis weight, the method of drying used, fiber type, and embossed rolls, the embossed paper towels exhibit different cushiness/softness and z-directional deformation. The commercially available asymmetrically embossed paper towels and toilet tissue papers used during compression testing were Charmin Ultra-Soft by P&G, KCC, P&G, and Walmart Stores Inc.
The spunlace nonwovens listed in the table below were laminated between the 0.6 mil polypropylene poly film and a 13.5 gsm polypropylene soft nonwoven backsheet using an Elmer's multipurpose spray adhesive. The table below displays measurements of a pre-load height of the sample material (HT-PL) and a height under an applied compression load of 500 grams (HT-LD) using the compression test described herein.
Laminates were also tested for cushiness and the compression versus extension plot is shown in
Carded and through air bonded nonwovens can be obtained from commercial nonwoven manufacturers like Shalag—Oxford, N.C., Texsus—Italy, Freudenberg, Berry plastics. Carded and through air bonded nonwovens exhibited a deformation range of 0.4 mm or higher under a compression force range of 50 grams to 500 grams using the compression test described herein. The basis weight of carded and TAB nonwoven can be 22 gsm or higher with fiber composition made of 100% polyester, 100% PP, bi-component fibers of PP/PE, PET/PE, PET/co-PET, PP/PET, blend of all these or selection of these fibers or blend of these fibers along with other natural fibers like cotton, bleached cotton, unbleached cotton, jute, ramie, flax, and the like.
The above specification and examples provide a complete description of the structure and use of illustrative embodiments. Although certain embodiments have been described above with a certain degree of particularity, or with reference to one or more individual embodiments, those skilled in the art could make numerous alterations to the disclosed embodiments without departing from the scope of this invention. As such, the various illustrative embodiments of the methods and systems are not intended to be limited to the particular forms disclosed. Rather, they include all modifications and alternatives falling within the scope of the claims, and embodiments other than the one shown may include some or all of the features of the depicted embodiment. For example, elements may be omitted or combined as a unitary structure, and/or connections may be substituted. Further, where appropriate, aspects of any of the examples described above may be combined with aspects of any of the other examples described to form further examples having comparable or different properties and/or functions, and addressing the same or different problems. Similarly, it will be understood that the benefits and advantages described above may relate to one embodiment or may relate to several embodiments.
The claims are not intended to include, and should not be interpreted to include, means-plus- or step-plus-function limitations, unless such a limitation is explicitly recited in a given claim using the phrase(s) “means for” or “step for,” respectively.
This application claims priority to U.S. Provisional Patent Application No. 62/091,929, filed Dec. 15, 2014, which is incorporated by reference in its entirety.
| Number | Date | Country | |
|---|---|---|---|
| 62091929 | Dec 2014 | US |
