CA2133299C - Tri-dimensional non-woven fabric for use as a skin-contacting cover layer of a sanitary absorbent article, a method for manufacturing the non-woven fabric and a sanitary article utilizing same - Google Patents
Tri-dimensional non-woven fabric for use as a skin-contacting cover layer of a sanitary absorbent article, a method for manufacturing the non-woven fabric and a sanitary article utilizing sameInfo
- Publication number
- CA2133299C CA2133299C CA002133299A CA2133299A CA2133299C CA 2133299 C CA2133299 C CA 2133299C CA 002133299 A CA002133299 A CA 002133299A CA 2133299 A CA2133299 A CA 2133299A CA 2133299 C CA2133299 C CA 2133299C
- Authority
- CA
- Canada
- Prior art keywords
- woven fabric
- density areas
- fiber density
- absorbent article
- fibers
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
Links
Classifications
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B32—LAYERED PRODUCTS
- B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
- B32B5/00—Layered products characterised by the non- homogeneity or physical structure, i.e. comprising a fibrous, filamentary, particulate or foam layer; Layered products characterised by having a layer differing constitutionally or physically in different parts
- B32B5/02—Layered products characterised by the non- homogeneity or physical structure, i.e. comprising a fibrous, filamentary, particulate or foam layer; Layered products characterised by having a layer differing constitutionally or physically in different parts characterised by structural features of a fibrous or filamentary layer
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- D—TEXTILES; PAPER
- D04—BRAIDING; LACE-MAKING; KNITTING; TRIMMINGS; NON-WOVEN FABRICS
- D04H—MAKING TEXTILE FABRICS, e.g. FROM FIBRES OR FILAMENTARY MATERIAL; FABRICS MADE BY SUCH PROCESSES OR APPARATUS, e.g. FELTS, NON-WOVEN FABRICS; COTTON-WOOL; WADDING ; NON-WOVEN FABRICS FROM STAPLE FIBRES, FILAMENTS OR YARNS, BONDED WITH AT LEAST ONE WEB-LIKE MATERIAL DURING THEIR CONSOLIDATION
- D04H1/00—Non-woven fabrics formed wholly or mainly of staple fibres or like relatively short fibres
- D04H1/40—Non-woven fabrics formed wholly or mainly of staple fibres or like relatively short fibres from fleeces or layers composed of fibres without existing or potential cohesive properties
- D04H1/44—Non-woven fabrics formed wholly or mainly of staple fibres or like relatively short fibres from fleeces or layers composed of fibres without existing or potential cohesive properties the fleeces or layers being consolidated by mechanical means, e.g. by rolling
- D04H1/46—Non-woven fabrics formed wholly or mainly of staple fibres or like relatively short fibres from fleeces or layers composed of fibres without existing or potential cohesive properties the fleeces or layers being consolidated by mechanical means, e.g. by rolling by needling or like operations to cause entanglement of fibres
- D04H1/48—Non-woven fabrics formed wholly or mainly of staple fibres or like relatively short fibres from fleeces or layers composed of fibres without existing or potential cohesive properties the fleeces or layers being consolidated by mechanical means, e.g. by rolling by needling or like operations to cause entanglement of fibres in combination with at least one other method of consolidation
-
- D—TEXTILES; PAPER
- D04—BRAIDING; LACE-MAKING; KNITTING; TRIMMINGS; NON-WOVEN FABRICS
- D04H—MAKING TEXTILE FABRICS, e.g. FROM FIBRES OR FILAMENTARY MATERIAL; FABRICS MADE BY SUCH PROCESSES OR APPARATUS, e.g. FELTS, NON-WOVEN FABRICS; COTTON-WOOL; WADDING ; NON-WOVEN FABRICS FROM STAPLE FIBRES, FILAMENTS OR YARNS, BONDED WITH AT LEAST ONE WEB-LIKE MATERIAL DURING THEIR CONSOLIDATION
- D04H1/00—Non-woven fabrics formed wholly or mainly of staple fibres or like relatively short fibres
- D04H1/40—Non-woven fabrics formed wholly or mainly of staple fibres or like relatively short fibres from fleeces or layers composed of fibres without existing or potential cohesive properties
- D04H1/44—Non-woven fabrics formed wholly or mainly of staple fibres or like relatively short fibres from fleeces or layers composed of fibres without existing or potential cohesive properties the fleeces or layers being consolidated by mechanical means, e.g. by rolling
- D04H1/46—Non-woven fabrics formed wholly or mainly of staple fibres or like relatively short fibres from fleeces or layers composed of fibres without existing or potential cohesive properties the fleeces or layers being consolidated by mechanical means, e.g. by rolling by needling or like operations to cause entanglement of fibres
- D04H1/48—Non-woven fabrics formed wholly or mainly of staple fibres or like relatively short fibres from fleeces or layers composed of fibres without existing or potential cohesive properties the fleeces or layers being consolidated by mechanical means, e.g. by rolling by needling or like operations to cause entanglement of fibres in combination with at least one other method of consolidation
- D04H1/49—Non-woven fabrics formed wholly or mainly of staple fibres or like relatively short fibres from fleeces or layers composed of fibres without existing or potential cohesive properties the fleeces or layers being consolidated by mechanical means, e.g. by rolling by needling or like operations to cause entanglement of fibres in combination with at least one other method of consolidation entanglement by fluid jet in combination with another consolidation means
-
- D—TEXTILES; PAPER
- D04—BRAIDING; LACE-MAKING; KNITTING; TRIMMINGS; NON-WOVEN FABRICS
- D04H—MAKING TEXTILE FABRICS, e.g. FROM FIBRES OR FILAMENTARY MATERIAL; FABRICS MADE BY SUCH PROCESSES OR APPARATUS, e.g. FELTS, NON-WOVEN FABRICS; COTTON-WOOL; WADDING ; NON-WOVEN FABRICS FROM STAPLE FIBRES, FILAMENTS OR YARNS, BONDED WITH AT LEAST ONE WEB-LIKE MATERIAL DURING THEIR CONSOLIDATION
- D04H1/00—Non-woven fabrics formed wholly or mainly of staple fibres or like relatively short fibres
- D04H1/40—Non-woven fabrics formed wholly or mainly of staple fibres or like relatively short fibres from fleeces or layers composed of fibres without existing or potential cohesive properties
- D04H1/58—Non-woven fabrics formed wholly or mainly of staple fibres or like relatively short fibres from fleeces or layers composed of fibres without existing or potential cohesive properties by applying, incorporating or activating chemical or thermoplastic bonding agents, e.g. adhesives
Abstract
A tri-dimensional non-woven fabric particularly well-suited for use as a skin-contacting cover layer of a sanitary absorbent product such as a sanitary napkin, a diaper, a urinary pad, an adult brief, a wound dressing, or a nursing pad, among others. The non-woven fabric is characterized by a pattern of elongated and alternating high and low fiber density areas. Such structure has the ability of directing a discharge of body exudate to disperse over the surface of the non-woven fabric in a preferential direction. The non-woven fabric also has the ability of dynamically inducing body exudate to migrate through the low fiber density areas when the fibrous network is subjected to repeated bending or twisting movements. The invention also extends to a method for manufacturing the aforesaid non-woven fabric and to a sanitary article utilizing same. The invention further extends to a sanitary absorbent article utilizing a novel skin-contacting cover layer capable to establish and maintain an intimate liquid-communicative relationship with an absorbent core of the sanitary absorbent article without any adhesive.
Description
TITLE: TRI-DIMENSIONAL NON-WOVEN FABRIC FOR U8E AS A
SRIN-CONTACTING COVER LAYER OF A SANITARY
ABSORBENT ARTICLE, A NETHOD FOR MANUFACTURING
THE NON-WOVEN FABRIC AND A SANITARY ARTICLE
UTILIZING SANE
FIELD OF THE lNv~..lON
The present invention relates to a non-woven fabric particularly well-suited for use as a skin-contacting cover layer of a sanitary absorbent article such as a sanitary napkin, a diaper, a urinary pad, an adult brief, a wound dressing or a nursing pad, among others. In a most preferred embodiment, the non-woven fabric has the ability of guiding a discharge of body exudate to disperse longitudinally on the absorbent article surface to reduce the potential risk of failure as a result of overflow leakage at the sides. In addition, the non-woven fabric is capable of dynamically inducing body exudate to migrate therethrough in order to reduce the residence time of the liquid discharge on the cover layer of the absorbent article. The invention also extends to a method for manufacturing the non-woven fabric and to a sanitary absorbent article utilizing same. Furthermore, the invention extends to a sanitary absorbent article utilizing a skin-contacting cover layer united in an intimate liquid-communicative relationship with the absorbent core substantially without any adhesive.
BACRGROUND OF THE lNv~.,lON
s The ability of a sanitary absorbent article to efficiently capture and retain a discharge of body exudate is the result of a cooperative relationship between a plurality of superposed layers of porous material having different liquid-absorbency characteristics. In its simplest form, a laminated absorbent article comprises an absorbent core whose function is to permanently trap the liquid discharge, which is overlaid by a liquid-permeable cover layer that in use contacts the skin of the wearer.
Ideally, a cover layer should be able to manifest a very high liquid take-up rate in order to capture on contact a liquid discharge. This feature is desirable for two reasons. Firstly, a high liquid take-up rate reduces the potential risk of failure due to liquid leaking past the edges of the sanitary article and staining the wearer's clothes. Secondly, the unpleasant sensation of wetness, due to extended contact between free body exudate in the process of being acquired by the cover layer and the skin, is diminished.
In addition to the criteria expressed above, the cover layer of a sanitary absorbent article should reduce 21332~9 as much as possible the undesirable wet-back phenomenon which occurs when liquid captured in the absorbent core migrates back to the skin-contacting surface of the cover layer. The wet-back phenomenon is most likely to occur when the sanitary absorbent article is saturated with liquid and it is subjected to compression, such as when the wearer adopts a seating posture.
In an attempt to reduce the possibility of wet-back, attempts have been made in the past to design a cover exhibiting unidirectional flow characteristics. More particularly, such cover layer is capable of efficiently transferring liquid toward the absorbent core, however it manifests a higher resistance to liquid migration in the opposite direction. Those principles have been embodied in a sanitary napkin commercialized by Johnson & Johnson under the trademark STAYFREE.
Another area of interest which greatly influences the functionality of a cover layer is the quality of the interface between the cover layer and the absorbent core.
To achieve the objective of an intimate liquid-communicative relationship between these components, the prior art suggest to use an adhesive to bond the cover layer to the absorbent core at a multitude of pin-point sites dispersed over the entire interface cover/core.
Although this solution has some merits, it raises the 21332~9 production costs of the sanitary absorbent article.
Furthermore, the adhesive sites, however small, may create localized barriers to the migration of liquid toward the absorbent core.
s As a result of technology shortcomings and cost considerations the materials currently available for cover layer usage rarely combine all the desirable attributes discussed above. However, the technology in this field is far from having reached a state of maturity. Hence, significant developments are expected that could lead to materials that are better performers while being inexpensive to produce.
OBJECTS OF THE lNV~. ~ lON
A general object of this invention is a non-woven fabric having enhanced liquid-absorbency characteristics (hereinafter the term "liquid-absorbent" and "liquid-absorbency" shall only refer to the ability of a porousbody to take-up liquid, irrespective of how liquid-retentive the body is. For example, the cover layer of a sanitary absorbent article will be considered liquid-absorbent although the liquid merely transits through it before being trapped by the absorbent core of the sanitary article) particularly well-suited for use as a skin-contacting cover layer of a sanitary absorbent article.
21332~
A more specific object of the invention is a non-woven fabric capable of dynamically inducing body exudate discharged thereon to migrate through the non-woven fabric when its fibrous network is subjected to repeated, non-destructive deformations.
Another object of the invention is a method for manufacturing the aforesaid non-woven fabric.
A further object of the invention is a novel sanitary absorbent article having a skin-contracting cover layer which is capable of directing a discharge of body exudate to disperse longitudinally over the absorbent article.
Another object of the invention is a novel sanitary absorbing article in which the cover layer and the absorbent core are united substantially without adhesive, yet being in an intimate-liquid communicative relationship.
gUMMARY OF THE lNV ~ lON
As embodied and broadly described herein, the invention provides a tri-dimensional non-woven fabric comprising fibers in mechanical engagement forming a unitary foraminous network, said network including:
21332~9 - a multitude of discrete protuberant fiber packings protruding out of a plane of said unitary foraminous network, fibers in said packings being bonded to one another to consolidate said network;
- a plurality of high fiber density areas in said plane;
- a plurality of low fiber density areas (herein the expressions "high fiber density area" and "low fiber density area" are relative terms with no reference to any absolute fiber density values, used to indicate that in the former case a greater number of fibers per unit volume are present than in the latter case) in said plane, fibers in said low fiber density areas being capable of moving one relative to the other when said non-woven fabric is deformed in order to dynamically induce liquid discharged on said fabric to migrate through said low fiber density areas.
This non-woven fabric is particularly well-suited for use as a skin-contacting cover layer of a sanitary absorbent article.
In a preferred embodiment, the fiber distribution profile in the plane of the non-woven fabric is such as to provide a pattern of elongated and alternating high and low fiber density areas. Such fiber distribution profile has the ability of directing liquid discharged on the non-213329~
woven fabric to flow along a preferential direction, the longitudinal axis of the sanitary article, for instance.
This feature reduces the risks of failure of the sanitary article as a result of liquid leaking past its sides.
The ability of the fibers in the low fiber density areas to move one relative to the other disrupts the integrity of the surface tension developed between the liquid and the fibrous network. Accordingly, the residence time of a liquid discharge on the non-woven fabric can be reduced. This is particularly true for highly viscous body exudate. In practice, the inter-fiber motion observed to facilitate the liquid migration through the fabric is obtained when the fibrous network is locally distorted either in the machine or in the cross-directions. This deformation occurs when bending or twisting movements are imposed on the sanitary article by the wearer performing some sort of physical activity, such as walking or otherwise shifting the position of the legs.
The protuberant fiber packings which engage the absorbent core of the sanitary absorbent product, act to some degree as small spacers which in use reduce the possibility of wet-back.
In a most preferred embodiment, the tri-dimensional non-woven fabric in accordance with the invention includes 2133~93 rectilinear low fiber density areas alternating with high fiber density areas which are also rectilinear. The protuberant fiber packings originate solely from the high density areas and are located only on one side of the fabric in order to maintain the other side which forms the skin-contacting surface of the sanitary absorbent article, smooth, soft and comfortable to the wearer. To increase the resistance of the fibrous network to a loss of integrity in use, the non-woven fabric is treated with binder. Advantageously, the binder substance is applied at selected areas of the fibrous network, such as to the protuberant fiber packings, in order to preserve the inter-fiber movement ability in the low fiber density areas. The selective binder treatment also allows to preserve the softness of the skin-contacting surface of the non-woven fabric by preventing substantial amounts of binder to reach that surface and form a hard crust thereon.
To enhance the hydrophilicity of the non-woven fabric, it may be treated with wetting agent. Most preferably, the wetting agent is applied concurrently with the binder and it is also concentrated in the protuberant fiber packings.
The non-woven fabric in accordance with the invention can be manufacturing from a plurality of different fibers, such as polyester, acrylic, polypropylene, rayon and mixtures thereof, among others. Preferably the fibers have a denier in the range from about 1 to about 5. The density of the non-woven fabric is preferably in the range S from about O.OlS grams per cubic centimeter (g/cc) to about O.OS5 g/cc, and most preferably of about 0.035 g/cc.
As embodied and broadly described herein, the invention also provides a method for manufacturing a tri-dimensional non-woven fabric comprising fibers in mechanical engagement forming a generally planar unitary foraminous network, said network including:
- a multitude of discrete protuberant fiber packings lS protruding out of a plane of said unitary foraminous network;
- a plurality of high fiber density areas in said plane;
- a plurality of low fiber density areas in said plane, said method including the steps of:
a) jetting fluid against a web of loosely associated fibers which are capable of moving one relative to the other under the influence of applied fluid forces to mechanically entangle said loosely associated fibers 2S and form said unitary foraminous network; and b) bonding fibers in said packings to one another to consolidate said network, said method being completed substantially without bonding fibers in said low fiber density areas to one another for allowing fibers in said low fiber density areas to move relative to one another when said fabric is deformed in order to dynamically induce liquid discharged on said fabric to migrate through said low fiber density areas.
In a most preferred embodiment, the non-woven fabric in accordance with the invention is manufactured by the well-known ROSEBUD hydro-entanglement process which consists of confining the fibrous starting material between an apertured rotating drum and a foraminous screen-belt, and directing water jets at the fibrous material from the outside of the drum. The resulting lS fluid forces entangle the fibers into a pattern of alternating elongated high and low density areas lying in a common plane from which project the protuberant fiber packings. The packings distribution profile is determined by the pattern of apertures on the drum.
Downstream of the fiber entangling station, the non-woven fabric is treated with binder and wetting agent.
Most preferably, the binder and the wetting agent are in physical admixture and are applied to the non-woven fabric with a binder applicator roll contacting only the fiber packings in order to achieve the selective binder deposition discussed above.
213329~
As embodied and broadly described herein, the invention also provides a sanitary absorbent article, comprising:
- an absorbent core;
- a skin-contacting cover layer in liquid-communicative relationship with said absorbent core, said skin-contacting cover layer comprising a non-woven fabric having adjoining high and low fiber density areas, said low density areas being elongated and extending generally along a longitudinal axis of said absorbent article, whereby liquid discharged on said skin-contacting cover layer is guided to flow in said low fiber density areas longitudinally on said absorbent article.
As embodied and broadly described herein, the invention further provides a sanitary absorbent article, comprising:
- an absorbent layer made of soft particulate (for the purpose of this specification "particle" means a small amount of material without limitation of shape. A
fiber that is characterised by a geometrical extension along a preferential direction will be considered a particle. Hence, "particulate material" covers a material made of fibers, particles having non-fibrous identity or a combination of both) material;
- a skin-contacting, liquid-permeable cover layer including a plurality of downwardly projecting fiber packings, said fiber packings mechanically engaging said absorbent layer and constituting means for mechanically bonding said skin-contacting cover layer and said absorbent layer in a liquid-communicative relationship.
s The ability of a non-woven, skin-contacting cover layer to bond to the absorbent layer solely due to the mechanical engagement of the protuberant fiber packings with the particles of the absorbent layer is particularly advantageous over the traditional approach which utilizes adhesives because it allows to simplify the manufacturing process of the sanitary absorbent product. Furthermore, this method avoids the undesirable formation of localized pin-point liquid barriers at the interface between the cover/absorbent layer, due to the presence of adhesive.
This method requires soft absorbent layers i.e.
layers of material which is sufficiently compressible such that when the non-woven fabric described earlier is applied against the absorbent layer under a pressure of 0.5 pounds per square inch (psi) the protuberant fiber packings that face the absorbent layer are substantially embedded in the particulate material. An example of "soft" absorbent layer as per the above definition is pulp fluff. This material provides at its surface a relatively large number of loosely entangled fibers which can mechanically interlock with the protuberant fiber packings ~1332~9 of the cover in order to create a comparatively strong bond. On the other hand, materials such as compacted sphagnum moss may not work because the protuberant fiber packings cannot easily penetrate the dense sphagnum moss structure.
BRIEF DESCRIPTION OF THE DRAWINGS
- Figure 1 is a highly enlarged perspective view of a non-woven fabric in accordance with the present invention;
- Figure 2 is a top plan view of the non-woven fabric shown in Figure 1;
- Figure 3 is a highly enlarged cross-sectional view of a sanitary absorbent article which utilizes the non-woven fabric shown in Figures 1 and 2 as a skin-contacting cover layer;
- Figure 4 is a perspective schematical view of a fiber-entangling station for manufacturing the non-woven fabric in accordance with the invention;
- Figure 5 is a fragmentary, enlarged cross-sectional view of the fiber entangling station shown in Figure 4;
- Figure 6 is a fragmentary, yet further enlarged perspective view of the fiber entangling station shown in Figures 4 and 5, illustrating the mechanism of fabric formation;;
- Figure 7 is a schematical view of a binder applicator station for treating selected areas of the non-woven fabric with binder;
- Figure 8 is an elevational view of a binder applicator roll of the binder applicator station shown in Figure 7; and - Figure 9 is a photomicrograph of the non-woven fabric in accordance with the invention.
DESCRIPTION OF PREFERRED EMBODIMENTS
Figures 1, 2 and 9 of the annexed drawings illustrate in detail the structure of a three-dimensional non-woven fabric in accordance with the invention which is comprehensively designated by the reference numeral 10.
The non-woven fabric 10 has highly desirable liquid-absorption properties making the fabric particularly well-suited for use as a skin-contacting cover layer of a sanitary absorbent article such as a sanitary napkin, a - 15 _ 2133299 diaper, a urinary pad, an adult brief a wound dressing and a nursing pad, among others.
The fibrous network of the non-woven fabric 10 displays randomly oriented and mechanically interlocked fibers which are grouped in band-shaped, high fiber density areas 12 which are generally parallel with one another and extend in the machine direction of the non-woven fabric 10. The high-fiber density areas 12 are transversely spaced apart from one another defining therebetween narrow strip-like, low fiber density areas 14. The resulting pattern of alternating high and low fiber density areas 12 and 14 provides a planar multi-channel structure capable of directing a liquid discharge on the non-woven fabric 10 to disperse on the fabric surface in a preferential direction, as it will be subsequently discussed in detail.
From the high fiber density areas 12 project equidistant fiber packings 16 which are individually constituted by an aggregate of randomly oriented and mechanically interlocked fibers. Collectively, the fiber packings 16 form a staggered pattern and provide the three-dimensional character of the non-woven fabric 10.
In order to increase the resistance of the non-woven fabric 10, it is treated with binder which consolidates 213329~
the fibrous network. The binder substance, when cured, establishes bonds between adjacent fibers and prevents them from moving one relative to the other. Accordingly, the tenacity of the non-woven fabric 10 increases by virtue of a reduction in the inter-fiber displacement when destructive forces act on the non-woven fabric.
An important aspect of the invention resides in that the binder is applied only at selected areas of the non-woven fabric 10, namely on the fiber packings 16 for thepurpose of allowing a limited inter-fiber displacement in the low fiber density areas 16 when the non-woven fabric 10 is folded, stretched or otherwise distorted, in a non-destructive fashion. In contrast, the binder precludes any inter-fiber displacement in the fiber packings 16.
The limited freedom of movement that the fibers in the low fiber density area 16 acquire as a result of the selective binder deposition is another important characteristic of the invention. This feature increases the liquid take-up rate of the non-woven fabric by dynamically inducing the liquid to penetrate in the fibrous network when the latter is subjected to repeated deformations by the action of external forces. This characteristic will be discussed in detail during the description of possible applications of the non-woven 213~23g fabric 10 as a cover layer for a sanitary napkin, which is found later in this specification.
Figures 4, 5 and 6 of the annexed drawings illustrate with an increasing level of detail a fiber-entangling station which generates the fibrous network depicted in Figures 1 and 2. The fiber-entangling station, identified comprehensively by the reference numeral 18, comprises a hollow metallic drum 20 mounted for rotation about its longitudinal axis into a suitable cradle (not shown). A
drive mechanism (not shown) is provided to rotate the drum 20 in the counter-clockwise direction, as shown by the arrows 22 at a controlled speed. The drive mechanism is of a well-known construction and does not form part of this invention. The shell of the drum 20 is provided on its entire surface with circular apertures 24 arranged according to a staggered pattern. The apertures 24 are separated from one another by solid land areas 26 corresponding to closed or impermeable zones of the drum 20.
The fiber-entangling station 18 also comprises an endless screen belt 28 which is set in a partially overlapping relationship with the drum 20 by means of guide rollers 30. Support rollers 32 are positioned at the corners of an imaginary rectangle and act, in conjunction with guide rollers 30, to tension and 21~329~
establish a path of travel for the screen belt 28. One or more of the rollers 30 or 32 are drive rollers for advancing the belt 28 in unison with the drum 20.
A manifolds 34 is mounted outside the structure formed by the screen belt 28 and the hollow perforated drum 20 to create liquid streams for rearranging loosely associated fibers confined between the drum 20 and the screen belt 28 into the unitary fibrous network 10. The manifold 34 includes a metallic casing 38 with a concave wall 40 which faces the screen belt/drum and has a curvature corresponding to the curvature of the drum shell. On the concave wall 40 are mounted a series of nozzles 42 in liquid communication with the casing 38 so as to create a plurality of fluid streams impinging on the screen belt 28. The concave shape of the wall 40 permits the orientation of each nozzle 42 into a radial direction relative to the screen belt/drum and also to position the extremity of each nozzle at exactly the same distance from the screen belt 28.
The nozzles 42 are grouped into four parallel rows, each row extending along the longitudinal axis of the drum 20. The nozzles 42 produce fluid streams, preferably water under the form of flat cones lying in respective imaginary horizontal planes which contain the drum longitudinal axis, the nozzles in the same row being 213329~
spaced apart from one another by a distance so that a certain overlap occurs between streams from adjacent nozzles immediately in front of the screen belt 28. The gap between successive nozzle rows is relatively small so that for all practical purposes, the individual fluid streams produced by the nozzles 42 are united into a common fluid front acting on the screen belt 28 and the drum 20.
The operation of the fiber entangling station 18 is as follows. A web 44 of starting material, containing loosely associated fibers, thus capable of movement one relative to the other, is supplied in a continuous sheet form from a supply station (not shown) that will also card the fibers in the machine direction, and is deposited over the horizontally extending forward run of the screen belt 28 preceding the section of the screen belt which loops the hollow drum 20. Fibers of material in the group comprising polyester, acrylic, polypropylene, rayon and mixtures thereof have been found satisfactory. The web 44 is pulled between the hollow drum 20 and the screen belt 28, which form in combination a fluid permeable, web confining and supporting structure guiding and advancing the web 44 through the water streams from the manifold 34 applying fluid forces to the web fibers to entangle them and form a unitary network.
When the web 44 passes through the fluid treatment zone the fibers in the area of the web 44 on which the fluid front generated by the manifolds acts, are subjected to the influence of fluid forces which cause the fibers to migrate toward preferential positions, overcoming inter-fiber friction, fiber to screen belt friction and fiber to drum friction. The fibers leaving the treatment zone are reoriented into a reticular network whose basic configuration is dependent upon the drum/screen belt combination.
Further details on the principle for manufacturing a non-woven fabric by fluid entanglement can be found in the prior art. At this end, the reader may consider the following Canadian patents granted to Johnson ~ Johnson, USA which constitute references of interest to the present subject. The subject matter of these patents is incorporated herein by reference.
915,398 November 28, 1972 915,397 November 28, 1972 915,398 November 28, 1972 915,399 November 28, 1972 - 21 _213 329 9 915,400 November 28, 1972 915,401 November 28, 1972 915,402 November 28, 1972 915,403 November 28, 1972 915,408 November 28, 1972 1,143,929 April 5, 1983 The non-woven fabric generated by the fiber entangling station 18 is processed at a binder applicator station, shown in Figures 7 and 8, which applies a solution of binder to the non-woven fabric. The binder, when cured, solidifies and consolidates the non-woven fabric, increasing its resistance. Binders are commercially available compounds and the selection of a particular binder depends upon the desired characteristics of the final product. The following binders have been found satisfactory: vinyl ethylene, vinyl chloride, vinyl acetate, vinyl acrylate, polyvinyl alcohol, polyvinyl acetate, carboxylated polystyrene, polyacrylonitrile, rubber polyethylene and mixtures thereof.
The binder applicator station, denoted comprehensively by the reference numeral 46 comprises a coating roll 48 having a lower end immersed in a binder 21~293 bath. A back-up roll 50 is provided above the roll 48 to define therewith a nip through which the non-woven fabric 10 passes. As the roll 48 rotates, a thin film of binder adheres thereto which is deposited on the non-woven fabric 10 through rolling contact therewith. A scraper blade 56 is provided to control the thickness of the binder film adhering to the surface of the coating roll 48. A smooth-surfaced coating roll 48 which achieve a uniform binder deposition, which is acceptable for some applications.
However, it is preferred to apply the binder according to a pattern of co-extensive lines which has the advantage of sufficiently consolidating the non-woven fabric without stiffening the fibrous network to the point where it becomes uncomfortable to wear. To achieve the desired binder deposition pattern, a coating roll having a relief surface is required, the recessed areas of the relief surface constituting the binder transfer surfaces. An example of such roll is shown in Figure 8. The circumferential surface of the roll is machined to form a multitude of axially extending zig-zag grooves 52 which are parallel to one another.
An important aspect of the binder treatment resides in that the binder is applied on the surface of the non-woven fabric which contains the protuberant fiber packings16. This is achieved by setting the orientation of the non-woven fabric through the binder application station 21~32~9 46, whereby solely the fiber packings 16 engage the coating roll 48.
In a most preferred embodiment, the binder applicator station is also used as an agency for treating the non-woven fabric with wetting agent in order to enhance its hydrophilicity. The wetting agent is applied to the non-woven fabric in physical admixture with the binder solution. At this end, the solution containing the selected binder and wetting agent is prepared and it is supplied to the binder applicator station 46.
In a specific example, a fabric according to the invention has been produced under the following process conditions.
~luid-entangling station Parameters starting material polye~ter fibers 3 denier apertures 24 on drum Staggered patterD -46 apertures per inch both ;D ~he ~;.. ' ' aDd the axial directions - 30% open area 20Screen belt 28 24 ~trands per inch both ;D the machine and the transver~e direction - 55 % open area Manifold 34 four rows of Do~es 15-10-0~
fluid supply pressure ~30 pouDds per ~uare inch gage (p~ig) 2~33~99 The first numeral in the nozzle size refers to the spread angle of the spray produced by the nozzle while the second numeral is ten times the flow rate of the nozzle expressed in U.S. gallons per minute at a pressure of 40 psig. The third numeral refers to tilt angle of the spray relative a horizontal plane. Accordingly, a 15-10-00 size means that the angle of the spray is 150, the nozzle flows 1.0 U.S. gallons per minute at 40 psig and the spray is horizontally oriented.
Binder applicator station Parameters Acrylic binder and Triton GR-5M surfact~mt as wetting agent~ooth ~ ' ' by Union Carbide). The solution Binder solution hAs a surfact~mt contents (solids) which is less than 1%.
width - 0.46 rmn depth - 0.46 rnrn 15Binder transfer grooves on 6 grooves per inch ( ~ . ' . ' direction) roll 48 Direction of rotation of Opposite to direction of ~ _ of the non-woven f~bric roll 48 The non-woven fabric generated by the fiber entangling station 18 under the above process conditions is characterized by a basis weight of about 28 g/m2, a thickness of 0.74 mm measured at a pressure of 3.45 Kpa and a density of 0.035 g/cc. The protuberances 16 project - 25 _ 2133~9 from the plane of the non-woven fabric to a height of approximately 1.575 mm and the number of protuberances per square inch is of 43. The approximate transverse dimensions of the high and low fiber density areas 12 and 14 is of 2 mm.
This non-woven fabric is particularly suitable for manufacturing cover layers of disposable sanitary articles, such as sanitary napkins. Figure 3 of the annexed drawings illustrates a sanitary napkin construction 58 comprising an absorbent core 60 made of pulp fluff and a body-contacting cover layer 62 made from the non-woven fabric 10. Note that the protuberances 16 face the pulp fluff material and they are embedded therein to an appreciable degree, by virtue of the high compressibility of the absorbent core. Yet, the main body of the cover 62 that contains the high and low fiber density areas 12 and 14 is only in gentle contact with the absorbent core 60 since the protuberances 16 act as spacers to some degree. This arrangement manifests a significant reduction in wet-back, particulary for highly viscous menses.
Without the intent of being bound by a specific theory, the present inventor explains the observed wet back reduction by the ability of the protuberances 16 to act as spacers and reduce the incidence of firm contact 213329~
between the main body of the cover 62 and the absorbent core 60. As a consequence, a path of higher resistance is developed preventing liquid in the absorbent core 60 from freely migrating back onto the skin-contacting surface of the cover 62. At the same time the protuberances 16 constitute individual pathways, allowing liquid discharged on the cover 62 to quickly migrate within the absorbent core 60. The surfactant contained in the protuberances 16 enhances this lead-in action. In short, the cover 62 behaves as a non-linear liquid path, allowing significantly more liquid to flow toward the absorbent core 60 than in the opposite direction.
The ability of the cover 62 to quickly acquire a liquid discharge is enhanced by the relative mobility of the fibers in the low fiber density areas 14. For, instance, by imparting a bending or twisting movement on the sanitary napkin 10 (this deformation occurs when the wearer is performing some sort of physical activity, such as walking or otherwise shifting the position of the legs) the fibers in the areas 14 are caused to shift position and as a consequence, they disrupt the surface tension developed between the menstrual liquid and the cover 62.
Hence, the liquid is dynamically induced to penetrate the cover 62.
21~3299 Another interesting advantage of the cover 62 is the high frictional resistance developed by the protuberances 16 against the absorbent core 60 that enables to assemble the sanitary napkin 58 free of adhesive at the interface cover/absorbent core. The capability of the cover 62 to grip the absorbent core 60, or any other absorbent layer, such as a transfer layer that may be used between the cover 62 and the core 60, is observable when the absorbent network engaging the cover 60 is soft and compressible.
Most preferably, the absorbent network contains a significant amount of fibers capable of mechanically entangling themselves around the protuberances 16. Pulp fluff is an example of material that works well.
The advantage of eliminating or at least substantially reducing the adhesive at the interface cover/absorbent layer is two fold. First the manufacturing cost of the product is reduced. Second, the pin-point adhesive zones that constitute individual liquid barriers are eliminated to further enhance the liquid take-up rate of the sanitary napkin 58.
The improvement in terms of adherence of the non-woven fabric 10 against a pulp fluff absorbent layer is demonstrated by a test that consists of measuring the horizontal force required to cause a displacement of the non-woven fabric sample over the absorbent core of a sanitary napkin commercialized by Johnson & Johnson under the name STAYFREE MAXI. The test procedure consists of urging the sample against the absorbent core under different pressures and observing the force required to displace the sample for each pressure level. The sample is co-extensive with the absorbent core and the pressure is applied uniformly thereon. The test data is summarized in the following table.
Horizontal pulling force (grams) SamplePres ure 0.05PressurePressure 0.51 p5i 0. 125 psi psi Invention 310 478 1575 Control* 293 460 1357 Difference(%) 5.8 3.9 16.1 ~ The control is the cover layer of a sanitary napk_n commercialize~
by Johnson & Johnson under the name STAYFREE MAXI.
It is apparent that the non-woven fabric in accordance with the invention exhibits a significant improvement in terms of adherence with the pulp fluff absorbent core.
The process for assembling the sanitary napkin 58 differs from the prior art by the omission of the adhesive application step between the cover and the absorbent core.
In the present case, the cover 62 is retained to the 21332~9 napkin structure by thermally or adhesively bonding the marginal portions of the cover to adjoining marginal portions of the barrier layer so as to totally enclose the absorbent system which may be a single or a multi-layered structure. It is preferable to complete the manufacturing process by tightly compressing the cover 62 against the underlying absorbent layer to cause the protuberances 16 to penetrate that layer for better mechanical engagement.
Applications of the product and methods of the present invention for sanitary and other health-care uses can be accomplished by any sanitary protection, incontinence, medical and absorbent methods and techniques as are presently or prospectively known to those skilled in the art. Thus, it is intended that the present application covers the modifications and variations of this invention provided that they come within the scope of the appended claims and their equivalents.
SRIN-CONTACTING COVER LAYER OF A SANITARY
ABSORBENT ARTICLE, A NETHOD FOR MANUFACTURING
THE NON-WOVEN FABRIC AND A SANITARY ARTICLE
UTILIZING SANE
FIELD OF THE lNv~..lON
The present invention relates to a non-woven fabric particularly well-suited for use as a skin-contacting cover layer of a sanitary absorbent article such as a sanitary napkin, a diaper, a urinary pad, an adult brief, a wound dressing or a nursing pad, among others. In a most preferred embodiment, the non-woven fabric has the ability of guiding a discharge of body exudate to disperse longitudinally on the absorbent article surface to reduce the potential risk of failure as a result of overflow leakage at the sides. In addition, the non-woven fabric is capable of dynamically inducing body exudate to migrate therethrough in order to reduce the residence time of the liquid discharge on the cover layer of the absorbent article. The invention also extends to a method for manufacturing the non-woven fabric and to a sanitary absorbent article utilizing same. Furthermore, the invention extends to a sanitary absorbent article utilizing a skin-contacting cover layer united in an intimate liquid-communicative relationship with the absorbent core substantially without any adhesive.
BACRGROUND OF THE lNv~.,lON
s The ability of a sanitary absorbent article to efficiently capture and retain a discharge of body exudate is the result of a cooperative relationship between a plurality of superposed layers of porous material having different liquid-absorbency characteristics. In its simplest form, a laminated absorbent article comprises an absorbent core whose function is to permanently trap the liquid discharge, which is overlaid by a liquid-permeable cover layer that in use contacts the skin of the wearer.
Ideally, a cover layer should be able to manifest a very high liquid take-up rate in order to capture on contact a liquid discharge. This feature is desirable for two reasons. Firstly, a high liquid take-up rate reduces the potential risk of failure due to liquid leaking past the edges of the sanitary article and staining the wearer's clothes. Secondly, the unpleasant sensation of wetness, due to extended contact between free body exudate in the process of being acquired by the cover layer and the skin, is diminished.
In addition to the criteria expressed above, the cover layer of a sanitary absorbent article should reduce 21332~9 as much as possible the undesirable wet-back phenomenon which occurs when liquid captured in the absorbent core migrates back to the skin-contacting surface of the cover layer. The wet-back phenomenon is most likely to occur when the sanitary absorbent article is saturated with liquid and it is subjected to compression, such as when the wearer adopts a seating posture.
In an attempt to reduce the possibility of wet-back, attempts have been made in the past to design a cover exhibiting unidirectional flow characteristics. More particularly, such cover layer is capable of efficiently transferring liquid toward the absorbent core, however it manifests a higher resistance to liquid migration in the opposite direction. Those principles have been embodied in a sanitary napkin commercialized by Johnson & Johnson under the trademark STAYFREE.
Another area of interest which greatly influences the functionality of a cover layer is the quality of the interface between the cover layer and the absorbent core.
To achieve the objective of an intimate liquid-communicative relationship between these components, the prior art suggest to use an adhesive to bond the cover layer to the absorbent core at a multitude of pin-point sites dispersed over the entire interface cover/core.
Although this solution has some merits, it raises the 21332~9 production costs of the sanitary absorbent article.
Furthermore, the adhesive sites, however small, may create localized barriers to the migration of liquid toward the absorbent core.
s As a result of technology shortcomings and cost considerations the materials currently available for cover layer usage rarely combine all the desirable attributes discussed above. However, the technology in this field is far from having reached a state of maturity. Hence, significant developments are expected that could lead to materials that are better performers while being inexpensive to produce.
OBJECTS OF THE lNV~. ~ lON
A general object of this invention is a non-woven fabric having enhanced liquid-absorbency characteristics (hereinafter the term "liquid-absorbent" and "liquid-absorbency" shall only refer to the ability of a porousbody to take-up liquid, irrespective of how liquid-retentive the body is. For example, the cover layer of a sanitary absorbent article will be considered liquid-absorbent although the liquid merely transits through it before being trapped by the absorbent core of the sanitary article) particularly well-suited for use as a skin-contacting cover layer of a sanitary absorbent article.
21332~
A more specific object of the invention is a non-woven fabric capable of dynamically inducing body exudate discharged thereon to migrate through the non-woven fabric when its fibrous network is subjected to repeated, non-destructive deformations.
Another object of the invention is a method for manufacturing the aforesaid non-woven fabric.
A further object of the invention is a novel sanitary absorbent article having a skin-contracting cover layer which is capable of directing a discharge of body exudate to disperse longitudinally over the absorbent article.
Another object of the invention is a novel sanitary absorbing article in which the cover layer and the absorbent core are united substantially without adhesive, yet being in an intimate-liquid communicative relationship.
gUMMARY OF THE lNV ~ lON
As embodied and broadly described herein, the invention provides a tri-dimensional non-woven fabric comprising fibers in mechanical engagement forming a unitary foraminous network, said network including:
21332~9 - a multitude of discrete protuberant fiber packings protruding out of a plane of said unitary foraminous network, fibers in said packings being bonded to one another to consolidate said network;
- a plurality of high fiber density areas in said plane;
- a plurality of low fiber density areas (herein the expressions "high fiber density area" and "low fiber density area" are relative terms with no reference to any absolute fiber density values, used to indicate that in the former case a greater number of fibers per unit volume are present than in the latter case) in said plane, fibers in said low fiber density areas being capable of moving one relative to the other when said non-woven fabric is deformed in order to dynamically induce liquid discharged on said fabric to migrate through said low fiber density areas.
This non-woven fabric is particularly well-suited for use as a skin-contacting cover layer of a sanitary absorbent article.
In a preferred embodiment, the fiber distribution profile in the plane of the non-woven fabric is such as to provide a pattern of elongated and alternating high and low fiber density areas. Such fiber distribution profile has the ability of directing liquid discharged on the non-213329~
woven fabric to flow along a preferential direction, the longitudinal axis of the sanitary article, for instance.
This feature reduces the risks of failure of the sanitary article as a result of liquid leaking past its sides.
The ability of the fibers in the low fiber density areas to move one relative to the other disrupts the integrity of the surface tension developed between the liquid and the fibrous network. Accordingly, the residence time of a liquid discharge on the non-woven fabric can be reduced. This is particularly true for highly viscous body exudate. In practice, the inter-fiber motion observed to facilitate the liquid migration through the fabric is obtained when the fibrous network is locally distorted either in the machine or in the cross-directions. This deformation occurs when bending or twisting movements are imposed on the sanitary article by the wearer performing some sort of physical activity, such as walking or otherwise shifting the position of the legs.
The protuberant fiber packings which engage the absorbent core of the sanitary absorbent product, act to some degree as small spacers which in use reduce the possibility of wet-back.
In a most preferred embodiment, the tri-dimensional non-woven fabric in accordance with the invention includes 2133~93 rectilinear low fiber density areas alternating with high fiber density areas which are also rectilinear. The protuberant fiber packings originate solely from the high density areas and are located only on one side of the fabric in order to maintain the other side which forms the skin-contacting surface of the sanitary absorbent article, smooth, soft and comfortable to the wearer. To increase the resistance of the fibrous network to a loss of integrity in use, the non-woven fabric is treated with binder. Advantageously, the binder substance is applied at selected areas of the fibrous network, such as to the protuberant fiber packings, in order to preserve the inter-fiber movement ability in the low fiber density areas. The selective binder treatment also allows to preserve the softness of the skin-contacting surface of the non-woven fabric by preventing substantial amounts of binder to reach that surface and form a hard crust thereon.
To enhance the hydrophilicity of the non-woven fabric, it may be treated with wetting agent. Most preferably, the wetting agent is applied concurrently with the binder and it is also concentrated in the protuberant fiber packings.
The non-woven fabric in accordance with the invention can be manufacturing from a plurality of different fibers, such as polyester, acrylic, polypropylene, rayon and mixtures thereof, among others. Preferably the fibers have a denier in the range from about 1 to about 5. The density of the non-woven fabric is preferably in the range S from about O.OlS grams per cubic centimeter (g/cc) to about O.OS5 g/cc, and most preferably of about 0.035 g/cc.
As embodied and broadly described herein, the invention also provides a method for manufacturing a tri-dimensional non-woven fabric comprising fibers in mechanical engagement forming a generally planar unitary foraminous network, said network including:
- a multitude of discrete protuberant fiber packings lS protruding out of a plane of said unitary foraminous network;
- a plurality of high fiber density areas in said plane;
- a plurality of low fiber density areas in said plane, said method including the steps of:
a) jetting fluid against a web of loosely associated fibers which are capable of moving one relative to the other under the influence of applied fluid forces to mechanically entangle said loosely associated fibers 2S and form said unitary foraminous network; and b) bonding fibers in said packings to one another to consolidate said network, said method being completed substantially without bonding fibers in said low fiber density areas to one another for allowing fibers in said low fiber density areas to move relative to one another when said fabric is deformed in order to dynamically induce liquid discharged on said fabric to migrate through said low fiber density areas.
In a most preferred embodiment, the non-woven fabric in accordance with the invention is manufactured by the well-known ROSEBUD hydro-entanglement process which consists of confining the fibrous starting material between an apertured rotating drum and a foraminous screen-belt, and directing water jets at the fibrous material from the outside of the drum. The resulting lS fluid forces entangle the fibers into a pattern of alternating elongated high and low density areas lying in a common plane from which project the protuberant fiber packings. The packings distribution profile is determined by the pattern of apertures on the drum.
Downstream of the fiber entangling station, the non-woven fabric is treated with binder and wetting agent.
Most preferably, the binder and the wetting agent are in physical admixture and are applied to the non-woven fabric with a binder applicator roll contacting only the fiber packings in order to achieve the selective binder deposition discussed above.
213329~
As embodied and broadly described herein, the invention also provides a sanitary absorbent article, comprising:
- an absorbent core;
- a skin-contacting cover layer in liquid-communicative relationship with said absorbent core, said skin-contacting cover layer comprising a non-woven fabric having adjoining high and low fiber density areas, said low density areas being elongated and extending generally along a longitudinal axis of said absorbent article, whereby liquid discharged on said skin-contacting cover layer is guided to flow in said low fiber density areas longitudinally on said absorbent article.
As embodied and broadly described herein, the invention further provides a sanitary absorbent article, comprising:
- an absorbent layer made of soft particulate (for the purpose of this specification "particle" means a small amount of material without limitation of shape. A
fiber that is characterised by a geometrical extension along a preferential direction will be considered a particle. Hence, "particulate material" covers a material made of fibers, particles having non-fibrous identity or a combination of both) material;
- a skin-contacting, liquid-permeable cover layer including a plurality of downwardly projecting fiber packings, said fiber packings mechanically engaging said absorbent layer and constituting means for mechanically bonding said skin-contacting cover layer and said absorbent layer in a liquid-communicative relationship.
s The ability of a non-woven, skin-contacting cover layer to bond to the absorbent layer solely due to the mechanical engagement of the protuberant fiber packings with the particles of the absorbent layer is particularly advantageous over the traditional approach which utilizes adhesives because it allows to simplify the manufacturing process of the sanitary absorbent product. Furthermore, this method avoids the undesirable formation of localized pin-point liquid barriers at the interface between the cover/absorbent layer, due to the presence of adhesive.
This method requires soft absorbent layers i.e.
layers of material which is sufficiently compressible such that when the non-woven fabric described earlier is applied against the absorbent layer under a pressure of 0.5 pounds per square inch (psi) the protuberant fiber packings that face the absorbent layer are substantially embedded in the particulate material. An example of "soft" absorbent layer as per the above definition is pulp fluff. This material provides at its surface a relatively large number of loosely entangled fibers which can mechanically interlock with the protuberant fiber packings ~1332~9 of the cover in order to create a comparatively strong bond. On the other hand, materials such as compacted sphagnum moss may not work because the protuberant fiber packings cannot easily penetrate the dense sphagnum moss structure.
BRIEF DESCRIPTION OF THE DRAWINGS
- Figure 1 is a highly enlarged perspective view of a non-woven fabric in accordance with the present invention;
- Figure 2 is a top plan view of the non-woven fabric shown in Figure 1;
- Figure 3 is a highly enlarged cross-sectional view of a sanitary absorbent article which utilizes the non-woven fabric shown in Figures 1 and 2 as a skin-contacting cover layer;
- Figure 4 is a perspective schematical view of a fiber-entangling station for manufacturing the non-woven fabric in accordance with the invention;
- Figure 5 is a fragmentary, enlarged cross-sectional view of the fiber entangling station shown in Figure 4;
- Figure 6 is a fragmentary, yet further enlarged perspective view of the fiber entangling station shown in Figures 4 and 5, illustrating the mechanism of fabric formation;;
- Figure 7 is a schematical view of a binder applicator station for treating selected areas of the non-woven fabric with binder;
- Figure 8 is an elevational view of a binder applicator roll of the binder applicator station shown in Figure 7; and - Figure 9 is a photomicrograph of the non-woven fabric in accordance with the invention.
DESCRIPTION OF PREFERRED EMBODIMENTS
Figures 1, 2 and 9 of the annexed drawings illustrate in detail the structure of a three-dimensional non-woven fabric in accordance with the invention which is comprehensively designated by the reference numeral 10.
The non-woven fabric 10 has highly desirable liquid-absorption properties making the fabric particularly well-suited for use as a skin-contacting cover layer of a sanitary absorbent article such as a sanitary napkin, a - 15 _ 2133299 diaper, a urinary pad, an adult brief a wound dressing and a nursing pad, among others.
The fibrous network of the non-woven fabric 10 displays randomly oriented and mechanically interlocked fibers which are grouped in band-shaped, high fiber density areas 12 which are generally parallel with one another and extend in the machine direction of the non-woven fabric 10. The high-fiber density areas 12 are transversely spaced apart from one another defining therebetween narrow strip-like, low fiber density areas 14. The resulting pattern of alternating high and low fiber density areas 12 and 14 provides a planar multi-channel structure capable of directing a liquid discharge on the non-woven fabric 10 to disperse on the fabric surface in a preferential direction, as it will be subsequently discussed in detail.
From the high fiber density areas 12 project equidistant fiber packings 16 which are individually constituted by an aggregate of randomly oriented and mechanically interlocked fibers. Collectively, the fiber packings 16 form a staggered pattern and provide the three-dimensional character of the non-woven fabric 10.
In order to increase the resistance of the non-woven fabric 10, it is treated with binder which consolidates 213329~
the fibrous network. The binder substance, when cured, establishes bonds between adjacent fibers and prevents them from moving one relative to the other. Accordingly, the tenacity of the non-woven fabric 10 increases by virtue of a reduction in the inter-fiber displacement when destructive forces act on the non-woven fabric.
An important aspect of the invention resides in that the binder is applied only at selected areas of the non-woven fabric 10, namely on the fiber packings 16 for thepurpose of allowing a limited inter-fiber displacement in the low fiber density areas 16 when the non-woven fabric 10 is folded, stretched or otherwise distorted, in a non-destructive fashion. In contrast, the binder precludes any inter-fiber displacement in the fiber packings 16.
The limited freedom of movement that the fibers in the low fiber density area 16 acquire as a result of the selective binder deposition is another important characteristic of the invention. This feature increases the liquid take-up rate of the non-woven fabric by dynamically inducing the liquid to penetrate in the fibrous network when the latter is subjected to repeated deformations by the action of external forces. This characteristic will be discussed in detail during the description of possible applications of the non-woven 213~23g fabric 10 as a cover layer for a sanitary napkin, which is found later in this specification.
Figures 4, 5 and 6 of the annexed drawings illustrate with an increasing level of detail a fiber-entangling station which generates the fibrous network depicted in Figures 1 and 2. The fiber-entangling station, identified comprehensively by the reference numeral 18, comprises a hollow metallic drum 20 mounted for rotation about its longitudinal axis into a suitable cradle (not shown). A
drive mechanism (not shown) is provided to rotate the drum 20 in the counter-clockwise direction, as shown by the arrows 22 at a controlled speed. The drive mechanism is of a well-known construction and does not form part of this invention. The shell of the drum 20 is provided on its entire surface with circular apertures 24 arranged according to a staggered pattern. The apertures 24 are separated from one another by solid land areas 26 corresponding to closed or impermeable zones of the drum 20.
The fiber-entangling station 18 also comprises an endless screen belt 28 which is set in a partially overlapping relationship with the drum 20 by means of guide rollers 30. Support rollers 32 are positioned at the corners of an imaginary rectangle and act, in conjunction with guide rollers 30, to tension and 21~329~
establish a path of travel for the screen belt 28. One or more of the rollers 30 or 32 are drive rollers for advancing the belt 28 in unison with the drum 20.
A manifolds 34 is mounted outside the structure formed by the screen belt 28 and the hollow perforated drum 20 to create liquid streams for rearranging loosely associated fibers confined between the drum 20 and the screen belt 28 into the unitary fibrous network 10. The manifold 34 includes a metallic casing 38 with a concave wall 40 which faces the screen belt/drum and has a curvature corresponding to the curvature of the drum shell. On the concave wall 40 are mounted a series of nozzles 42 in liquid communication with the casing 38 so as to create a plurality of fluid streams impinging on the screen belt 28. The concave shape of the wall 40 permits the orientation of each nozzle 42 into a radial direction relative to the screen belt/drum and also to position the extremity of each nozzle at exactly the same distance from the screen belt 28.
The nozzles 42 are grouped into four parallel rows, each row extending along the longitudinal axis of the drum 20. The nozzles 42 produce fluid streams, preferably water under the form of flat cones lying in respective imaginary horizontal planes which contain the drum longitudinal axis, the nozzles in the same row being 213329~
spaced apart from one another by a distance so that a certain overlap occurs between streams from adjacent nozzles immediately in front of the screen belt 28. The gap between successive nozzle rows is relatively small so that for all practical purposes, the individual fluid streams produced by the nozzles 42 are united into a common fluid front acting on the screen belt 28 and the drum 20.
The operation of the fiber entangling station 18 is as follows. A web 44 of starting material, containing loosely associated fibers, thus capable of movement one relative to the other, is supplied in a continuous sheet form from a supply station (not shown) that will also card the fibers in the machine direction, and is deposited over the horizontally extending forward run of the screen belt 28 preceding the section of the screen belt which loops the hollow drum 20. Fibers of material in the group comprising polyester, acrylic, polypropylene, rayon and mixtures thereof have been found satisfactory. The web 44 is pulled between the hollow drum 20 and the screen belt 28, which form in combination a fluid permeable, web confining and supporting structure guiding and advancing the web 44 through the water streams from the manifold 34 applying fluid forces to the web fibers to entangle them and form a unitary network.
When the web 44 passes through the fluid treatment zone the fibers in the area of the web 44 on which the fluid front generated by the manifolds acts, are subjected to the influence of fluid forces which cause the fibers to migrate toward preferential positions, overcoming inter-fiber friction, fiber to screen belt friction and fiber to drum friction. The fibers leaving the treatment zone are reoriented into a reticular network whose basic configuration is dependent upon the drum/screen belt combination.
Further details on the principle for manufacturing a non-woven fabric by fluid entanglement can be found in the prior art. At this end, the reader may consider the following Canadian patents granted to Johnson ~ Johnson, USA which constitute references of interest to the present subject. The subject matter of these patents is incorporated herein by reference.
915,398 November 28, 1972 915,397 November 28, 1972 915,398 November 28, 1972 915,399 November 28, 1972 - 21 _213 329 9 915,400 November 28, 1972 915,401 November 28, 1972 915,402 November 28, 1972 915,403 November 28, 1972 915,408 November 28, 1972 1,143,929 April 5, 1983 The non-woven fabric generated by the fiber entangling station 18 is processed at a binder applicator station, shown in Figures 7 and 8, which applies a solution of binder to the non-woven fabric. The binder, when cured, solidifies and consolidates the non-woven fabric, increasing its resistance. Binders are commercially available compounds and the selection of a particular binder depends upon the desired characteristics of the final product. The following binders have been found satisfactory: vinyl ethylene, vinyl chloride, vinyl acetate, vinyl acrylate, polyvinyl alcohol, polyvinyl acetate, carboxylated polystyrene, polyacrylonitrile, rubber polyethylene and mixtures thereof.
The binder applicator station, denoted comprehensively by the reference numeral 46 comprises a coating roll 48 having a lower end immersed in a binder 21~293 bath. A back-up roll 50 is provided above the roll 48 to define therewith a nip through which the non-woven fabric 10 passes. As the roll 48 rotates, a thin film of binder adheres thereto which is deposited on the non-woven fabric 10 through rolling contact therewith. A scraper blade 56 is provided to control the thickness of the binder film adhering to the surface of the coating roll 48. A smooth-surfaced coating roll 48 which achieve a uniform binder deposition, which is acceptable for some applications.
However, it is preferred to apply the binder according to a pattern of co-extensive lines which has the advantage of sufficiently consolidating the non-woven fabric without stiffening the fibrous network to the point where it becomes uncomfortable to wear. To achieve the desired binder deposition pattern, a coating roll having a relief surface is required, the recessed areas of the relief surface constituting the binder transfer surfaces. An example of such roll is shown in Figure 8. The circumferential surface of the roll is machined to form a multitude of axially extending zig-zag grooves 52 which are parallel to one another.
An important aspect of the binder treatment resides in that the binder is applied on the surface of the non-woven fabric which contains the protuberant fiber packings16. This is achieved by setting the orientation of the non-woven fabric through the binder application station 21~32~9 46, whereby solely the fiber packings 16 engage the coating roll 48.
In a most preferred embodiment, the binder applicator station is also used as an agency for treating the non-woven fabric with wetting agent in order to enhance its hydrophilicity. The wetting agent is applied to the non-woven fabric in physical admixture with the binder solution. At this end, the solution containing the selected binder and wetting agent is prepared and it is supplied to the binder applicator station 46.
In a specific example, a fabric according to the invention has been produced under the following process conditions.
~luid-entangling station Parameters starting material polye~ter fibers 3 denier apertures 24 on drum Staggered patterD -46 apertures per inch both ;D ~he ~;.. ' ' aDd the axial directions - 30% open area 20Screen belt 28 24 ~trands per inch both ;D the machine and the transver~e direction - 55 % open area Manifold 34 four rows of Do~es 15-10-0~
fluid supply pressure ~30 pouDds per ~uare inch gage (p~ig) 2~33~99 The first numeral in the nozzle size refers to the spread angle of the spray produced by the nozzle while the second numeral is ten times the flow rate of the nozzle expressed in U.S. gallons per minute at a pressure of 40 psig. The third numeral refers to tilt angle of the spray relative a horizontal plane. Accordingly, a 15-10-00 size means that the angle of the spray is 150, the nozzle flows 1.0 U.S. gallons per minute at 40 psig and the spray is horizontally oriented.
Binder applicator station Parameters Acrylic binder and Triton GR-5M surfact~mt as wetting agent~ooth ~ ' ' by Union Carbide). The solution Binder solution hAs a surfact~mt contents (solids) which is less than 1%.
width - 0.46 rmn depth - 0.46 rnrn 15Binder transfer grooves on 6 grooves per inch ( ~ . ' . ' direction) roll 48 Direction of rotation of Opposite to direction of ~ _ of the non-woven f~bric roll 48 The non-woven fabric generated by the fiber entangling station 18 under the above process conditions is characterized by a basis weight of about 28 g/m2, a thickness of 0.74 mm measured at a pressure of 3.45 Kpa and a density of 0.035 g/cc. The protuberances 16 project - 25 _ 2133~9 from the plane of the non-woven fabric to a height of approximately 1.575 mm and the number of protuberances per square inch is of 43. The approximate transverse dimensions of the high and low fiber density areas 12 and 14 is of 2 mm.
This non-woven fabric is particularly suitable for manufacturing cover layers of disposable sanitary articles, such as sanitary napkins. Figure 3 of the annexed drawings illustrates a sanitary napkin construction 58 comprising an absorbent core 60 made of pulp fluff and a body-contacting cover layer 62 made from the non-woven fabric 10. Note that the protuberances 16 face the pulp fluff material and they are embedded therein to an appreciable degree, by virtue of the high compressibility of the absorbent core. Yet, the main body of the cover 62 that contains the high and low fiber density areas 12 and 14 is only in gentle contact with the absorbent core 60 since the protuberances 16 act as spacers to some degree. This arrangement manifests a significant reduction in wet-back, particulary for highly viscous menses.
Without the intent of being bound by a specific theory, the present inventor explains the observed wet back reduction by the ability of the protuberances 16 to act as spacers and reduce the incidence of firm contact 213329~
between the main body of the cover 62 and the absorbent core 60. As a consequence, a path of higher resistance is developed preventing liquid in the absorbent core 60 from freely migrating back onto the skin-contacting surface of the cover 62. At the same time the protuberances 16 constitute individual pathways, allowing liquid discharged on the cover 62 to quickly migrate within the absorbent core 60. The surfactant contained in the protuberances 16 enhances this lead-in action. In short, the cover 62 behaves as a non-linear liquid path, allowing significantly more liquid to flow toward the absorbent core 60 than in the opposite direction.
The ability of the cover 62 to quickly acquire a liquid discharge is enhanced by the relative mobility of the fibers in the low fiber density areas 14. For, instance, by imparting a bending or twisting movement on the sanitary napkin 10 (this deformation occurs when the wearer is performing some sort of physical activity, such as walking or otherwise shifting the position of the legs) the fibers in the areas 14 are caused to shift position and as a consequence, they disrupt the surface tension developed between the menstrual liquid and the cover 62.
Hence, the liquid is dynamically induced to penetrate the cover 62.
21~3299 Another interesting advantage of the cover 62 is the high frictional resistance developed by the protuberances 16 against the absorbent core 60 that enables to assemble the sanitary napkin 58 free of adhesive at the interface cover/absorbent core. The capability of the cover 62 to grip the absorbent core 60, or any other absorbent layer, such as a transfer layer that may be used between the cover 62 and the core 60, is observable when the absorbent network engaging the cover 60 is soft and compressible.
Most preferably, the absorbent network contains a significant amount of fibers capable of mechanically entangling themselves around the protuberances 16. Pulp fluff is an example of material that works well.
The advantage of eliminating or at least substantially reducing the adhesive at the interface cover/absorbent layer is two fold. First the manufacturing cost of the product is reduced. Second, the pin-point adhesive zones that constitute individual liquid barriers are eliminated to further enhance the liquid take-up rate of the sanitary napkin 58.
The improvement in terms of adherence of the non-woven fabric 10 against a pulp fluff absorbent layer is demonstrated by a test that consists of measuring the horizontal force required to cause a displacement of the non-woven fabric sample over the absorbent core of a sanitary napkin commercialized by Johnson & Johnson under the name STAYFREE MAXI. The test procedure consists of urging the sample against the absorbent core under different pressures and observing the force required to displace the sample for each pressure level. The sample is co-extensive with the absorbent core and the pressure is applied uniformly thereon. The test data is summarized in the following table.
Horizontal pulling force (grams) SamplePres ure 0.05PressurePressure 0.51 p5i 0. 125 psi psi Invention 310 478 1575 Control* 293 460 1357 Difference(%) 5.8 3.9 16.1 ~ The control is the cover layer of a sanitary napk_n commercialize~
by Johnson & Johnson under the name STAYFREE MAXI.
It is apparent that the non-woven fabric in accordance with the invention exhibits a significant improvement in terms of adherence with the pulp fluff absorbent core.
The process for assembling the sanitary napkin 58 differs from the prior art by the omission of the adhesive application step between the cover and the absorbent core.
In the present case, the cover 62 is retained to the 21332~9 napkin structure by thermally or adhesively bonding the marginal portions of the cover to adjoining marginal portions of the barrier layer so as to totally enclose the absorbent system which may be a single or a multi-layered structure. It is preferable to complete the manufacturing process by tightly compressing the cover 62 against the underlying absorbent layer to cause the protuberances 16 to penetrate that layer for better mechanical engagement.
Applications of the product and methods of the present invention for sanitary and other health-care uses can be accomplished by any sanitary protection, incontinence, medical and absorbent methods and techniques as are presently or prospectively known to those skilled in the art. Thus, it is intended that the present application covers the modifications and variations of this invention provided that they come within the scope of the appended claims and their equivalents.
Claims (33)
1. A tri-dimensional non-woven fabric comprising fibers in mechanical engagement forming a unitary foraminous network, said network including:
- a multitude of discrete protuberant fiber packings protruding out of a plane of said unitary foraminous network, fibers in said packings being bonded to one another to consolidate said network;
- a plurality of high fiber density areas in said plane;
- a plurality of low fiber density areas in said plane, fibers in said low fiber density areas being capable of moving one relative to the other when said non-woven fabric is deformed in order to dynamically induce liquid discharged on said fabric to migrate through said low fiber density areas.
- a multitude of discrete protuberant fiber packings protruding out of a plane of said unitary foraminous network, fibers in said packings being bonded to one another to consolidate said network;
- a plurality of high fiber density areas in said plane;
- a plurality of low fiber density areas in said plane, fibers in said low fiber density areas being capable of moving one relative to the other when said non-woven fabric is deformed in order to dynamically induce liquid discharged on said fabric to migrate through said low fiber density areas.
2. A non-woven fabric as defined in claim 1, wherein said low fiber density areas are generally rectilinear.
3. A non-woven fabric as defined in claim 1, wherein said high fiber density areas are generally rectilinear.
4. A non-woven fabric as defined in claim 1, wherein said low fiber density areas alternate with said high fiber density areas.
5. A non-woven fabric as defined in claim 1, wherein said protuberant fiber packings project from said high fiber density areas.
6. A non-woven fabric as defined in claim 1, wherein said protuberant fiber packings contain fibers that are fixed one relative to the other.
7. A non-woven fabric as defined in claim 1, further comprising a binder for consolidating said network.
8. A non-woven fabric as defined in claim 1, further comprising an agent for enhancing a hydrophilicity of said network.
9. A non-woven fabric as defined in claim 1, wherein said fiber packings contain binder for consolidating said network.
10. A non-woven fabric as defined in claim 9, wherein said low fiber density areas are substantially free of binder.
11. A non-woven fabric as defined in claim 1, including fibers selected from the group consisting of polyester, acrylic, polypropylene, rayon and mixtures thereof.
12. A non-woven fabric as defined in claim 7, wherein said binder is selected from the group consisting of vinyl ethylene, vinyl chloride, vinyl acetate, vinyl acrylate, polyvinyl alcohol, polyvinyl acetate, carboxylated polystyrene, polyacrylonitrile, rubber polyethylene and mixtures thereof.
13. A non-woven fabric as defined in claim 1, having a density in the range from about 0.015 grams per cubic centimeter to about 0.055 grams per cubic centimeter.
14. A method for manufacturing a tri-dimensional non-woven fabric comprising fibers in mechanical engagement forming a generally planar unitary foraminous network, said network including:
- a multitude of discrete protuberant fiber packings protruding out of a plane of said unitary foraminous network;
- a plurality of high fiber density areas in said plane;
- a plurality of low fiber density areas in said plane, said method including the steps of:
a) jetting fluid against a web of loosely associated fibers which are capable of moving one relative to the other under the influence of applied fluid forces to mechanically entangle said loosely associated fibers and form said unitary foraminous network; and b) bonding fibers in said packings to one another to consolidate said network, said method being completed substantially without bonding fibers in said low fiber density areas to one another for allowing fibers in said low fiber density areas to move relative to one another when said fabric is deformed in order to dynamically induce liquid discharged on said fabric to migrate through said low fiber density areas.
- a multitude of discrete protuberant fiber packings protruding out of a plane of said unitary foraminous network;
- a plurality of high fiber density areas in said plane;
- a plurality of low fiber density areas in said plane, said method including the steps of:
a) jetting fluid against a web of loosely associated fibers which are capable of moving one relative to the other under the influence of applied fluid forces to mechanically entangle said loosely associated fibers and form said unitary foraminous network; and b) bonding fibers in said packings to one another to consolidate said network, said method being completed substantially without bonding fibers in said low fiber density areas to one another for allowing fibers in said low fiber density areas to move relative to one another when said fabric is deformed in order to dynamically induce liquid discharged on said fabric to migrate through said low fiber density areas.
15. A method as defined in claim 14, comprising the step of applying binder to said fiber packings to prevent fibers in said fiber packings from moving one relative to the other.
16. A method as defined in claim 15, comprising the step of contacting said fiber packings with a binder carrier surface.
17. A method as defined in claim 16, comprising the step of passing a side of said unitary foraminous network containing said fiber packings in contact with a rotating roll carrying binder on its surface.
18. A method as defined in claim 14, comprising the step of applying an agent to said unitary foraminous network to enhance its hydrophilicity.
19. A method as defined in claim 18, comprising the step of applying wetting agent to said fiber packings.
20. A method as defined in claim 16, comprising the step of applying binder to said fiber packings in physical admixture with wetting agent.
21. A sanitary absorbent article including a skin-contacting liquid-permeable layer comprising the non-woven fabric defined in claim 1.
22. A sanitary absorbent article as defined in claim 21, wherein said absorbent article is selected from the group consisting of sanitary napkin, diaper, urinary pad, adult brief, wound dressing and nursing pad.
23. A sanitary absorbent article, comprising:
- an absorbent layer;
- a skin-contacting cover layer in liquid-communicative relationship with said absorbent layer, said skin-contacting cover layer comprising a non-woven fabric having adjoining high and low fiber density areas, said low density areas being elongated and extending along a longitudinal axis of said absorbent article, whereby liquid discharged on said skin-contacting cover layer is guided to flow in said low fiber density areas longitudinally on said absorbent article; and said low fiber density areas being substantially free of binder to allow fibers in said low fiber density areas to move one relative to the other when said absorbent article is distorted, whereby dynamically inducing liquid discharged on said skin-contacting cover layer to migrate toward said absorbent layer through said low fiber density areas.
- an absorbent layer;
- a skin-contacting cover layer in liquid-communicative relationship with said absorbent layer, said skin-contacting cover layer comprising a non-woven fabric having adjoining high and low fiber density areas, said low density areas being elongated and extending along a longitudinal axis of said absorbent article, whereby liquid discharged on said skin-contacting cover layer is guided to flow in said low fiber density areas longitudinally on said absorbent article; and said low fiber density areas being substantially free of binder to allow fibers in said low fiber density areas to move one relative to the other when said absorbent article is distorted, whereby dynamically inducing liquid discharged on said skin-contacting cover layer to migrate toward said absorbent layer through said low fiber density areas.
24. An absorbent article as defined in claim 23, wherein said non-woven fabric is consolidated with binder.
25. An absorbent article as defined in claim 23, wherein said low fiber density areas are generally rectilinear.
26. An absorbent article as defined in claim 23, wherein said high fiber density areas are generally rectilinear.
27. An absorbent article as defined in claim 23, wherein said high fiber density areas alternate with said low fiber density areas in a transverse direction of said absorbent article.
28. An absorbent article as defined in claim 23, wherein said non-woven fabric is treated with wetting agent to enhance a hydrophilicity of said skin-contacting cover layer.
29. An absorbent article as defined in claim 23, wherein said non-woven fabric includes a plurality of downwardly projecting fiber packings engaging said absorbent layer to impede reverse liquid migration from said absorbent layer toward said skin-contacting cover layer.
30. A sanitary absorbent article, comprising:
- an absorbent layer made of soft particulate material;
- a skin-contacting, liquid-permeable cover layer, being a non-woven fabric, said non-woven fabric including:
- a plurality of downwardly extending projections, said projections engaging said absorbent layer and constituting means for mechanically bonding said skin-contacting cover layer and said absorbent layer in a liquid-communicative relationship;
- a plurality of fiber packings downwardly protruding from a plane of said non-woven fabric, said fiber packings forming said projections;
- a plurality of high fiber density areas in said plane; and - a plurality of low fiber density areas in said plane, fibers in said low fiber density areas being capable of moving one relative to the other when said non-woven fabric is deformed in order to dynamically induce liquid discharged on said fabric to migrate through said low fiber density areas.
- an absorbent layer made of soft particulate material;
- a skin-contacting, liquid-permeable cover layer, being a non-woven fabric, said non-woven fabric including:
- a plurality of downwardly extending projections, said projections engaging said absorbent layer and constituting means for mechanically bonding said skin-contacting cover layer and said absorbent layer in a liquid-communicative relationship;
- a plurality of fiber packings downwardly protruding from a plane of said non-woven fabric, said fiber packings forming said projections;
- a plurality of high fiber density areas in said plane; and - a plurality of low fiber density areas in said plane, fibers in said low fiber density areas being capable of moving one relative to the other when said non-woven fabric is deformed in order to dynamically induce liquid discharged on said fabric to migrate through said low fiber density areas.
31. A sanitary absorbent article as defined in claim 30, wherein fibers in said fiber packings are fixed one relative to the other.
32. A sanitary absorbent article as defined in claim 30 wherein said absorbent layer includes fibrous material.
33. A sanitary absorbent article as defined in claim 32 wherein said absorbent layer is made of pulp fluff.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA002133299A CA2133299C (en) | 1994-09-29 | 1994-09-29 | Tri-dimensional non-woven fabric for use as a skin-contacting cover layer of a sanitary absorbent article, a method for manufacturing the non-woven fabric and a sanitary article utilizing same |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA002133299A CA2133299C (en) | 1994-09-29 | 1994-09-29 | Tri-dimensional non-woven fabric for use as a skin-contacting cover layer of a sanitary absorbent article, a method for manufacturing the non-woven fabric and a sanitary article utilizing same |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CA2133299A1 CA2133299A1 (en) | 1996-03-30 |
| CA2133299C true CA2133299C (en) | 1999-07-27 |
Family
ID=4154430
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002133299A Expired - Lifetime CA2133299C (en) | 1994-09-29 | 1994-09-29 | Tri-dimensional non-woven fabric for use as a skin-contacting cover layer of a sanitary absorbent article, a method for manufacturing the non-woven fabric and a sanitary article utilizing same |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA2133299C (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20220000680A1 (en) * | 2018-11-30 | 2022-01-06 | Kimberly-Clark Worldwide, Inc. | Three-dimensional nonwoven materials and methods of manufacturing thereof |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB0208029D0 (en) * | 2002-04-06 | 2002-05-15 | Accantia Holdings Ltd | Fabric & application |
| DE102008038556A1 (en) * | 2008-06-26 | 2009-12-31 | Eswegee Vliesstoff Gmbh | Nonwoven fabric for use as a moisture-permeable, microporous semi-luxury packaging material |
-
1994
- 1994-09-29 CA CA002133299A patent/CA2133299C/en not_active Expired - Lifetime
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20220000680A1 (en) * | 2018-11-30 | 2022-01-06 | Kimberly-Clark Worldwide, Inc. | Three-dimensional nonwoven materials and methods of manufacturing thereof |
Also Published As
| Publication number | Publication date |
|---|---|
| CA2133299A1 (en) | 1996-03-30 |
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