RU2564613C2 - Absorbing composite with resilient layer manufactured by combined moulding - Google Patents

Abstract

FIELD: medicine.

SUBSTANCE: claimed is an absorbing composite, located in an absorbing product between the upper sheet and the lower sheet, with the absorbing composite including the first receiving layer, located between the upper sheet and the lower sheet, and a retaining layer, located between the upper sheet and the lower sheet; one of the first receiving and retaining layer includes a resilient material of combined moulding. When the first receiving layer includes the resilient material of combined moulding, the retaining layer includes one of a fluff material/super-absorbing material of high density with hydrogen bonds, hydraulically interlaced material, composite material super-absorbing polymer/adhesive and a foamed material. The absorbing composite can additionally include a distribution layer, located between the upper sheet and the lower sheet, with the distribution material including one of the blown from the melt microfibrous material, hydraulically interlaced material and foamed material.

EFFECT: task of the invention consists in the creation of the absorbing product, which has sufficient resilience to prevent the sanitary towel folding, provision of improved fitting and comfort for the user.

22 cl, 11 dwg, 2 tbl

Description

BACKGROUND

This application has priority on the basis of application No. 61 / 324,982, filed April 16, 2010. Application No. 61 / 324,982 is fully incorporated here by reference.

The development of highly absorbent products for urine, blood and blood-based fluids such as pads and incontinence products, menstrual pads), tampons, dressings, bandages and surgical sheets can be difficult. In the case of incontinence pads and menstrual pads, for example, consumers are accustomed to expect a high level of performance in terms of comfort and fit, fluid retention, and minimal contamination. Mainly, leakage of liquid from the panty liner is considered unacceptable. Improving the performance of such gaskets continues to be a difficult task, although many improvements have been made both in the structures and in the materials used in such structures. Preventing leakage, especially along the hips, without compromising fit and comfort, does not always match the consumer’s desired needs.

The absorbent structures of currently available pads typically contain one or more fibrous layers to absorb the discharged liquids from the permeable top sheet and distribute them to a lower storage area. Absorbent structures for relatively thin variations of prior art products include an absorbent liquid or a receiving layer that is adjacent to the permeable topsheet. This receiving layer is usually made of an air-laid web or synthetic non-woven material. Below this receiving layer is the main absorbent core, which is usually made of an air laid web or a wet laid web.

The absorbent structures of the prior art made of fibrous layers have many problems, one of which is difficulty in ensuring that the top sheet is dry, such structures also have a greater likelihood of contamination of clothing and body. This was due to the fact that the absorbent structure loses elasticity, which leads to knocking down the gasket. This loss of elasticity and subsequent knocking down also led to the fact that the gaskets of the prior art provided poor fit and user comfort. The conclusion that traditional absorbent structures and traditional absorbent fiber webs did not solve this problem was made in US patent No. 5849805, Dyer.

One of the decisions taken to replace the fibrous receiving and absorbent layers with foam, such as INFINICEL foam, was used on conventional ALWAYS INFINITY gaskets available from The Procter and Gamble Company, Cincinnati, Ohio. Such foamed materials are more expensive than fibrous webs.

Co-forming non-woven webs, such as composite materials from a matrix of meltblown fibers and an absorbent material (e.g., fluffy wood pulp fibers), have been used as an absorbent layer in a wide variety of applications, including absorbent products, absorbent dry wipes, wet wipes, and mops. Most conventional co-forming webs use meltblown fibers formed from polypropylene homopolymers. One problem that sometimes arises with such co-molding materials, however, is that co-molding materials may not be sufficiently resilient when subjected to bending forces. For example, when a joint-formed napkin is wrinkled, the joint-molding material may not return to its original flat, unreached state. As another example, co-molding material used as an absorbent core in an absorbent personal care product may tend to curl.

Thus, there is currently a need for an improved nonwoven web of co-molding material for use in various applications, which exhibits increased resistance to bending forces and demonstrates a tendency to return to a flat state after it has been folded. Such an improved co-molding non-woven fabric may be combined with various other materials for the manufacture of next-generation absorbent composites for use in absorbent personal care products.

SUMMARY OF THE INVENTION

The inventors have made research and development efforts to improve absorbent products, and have developed absorbent composites for use in an absorbent core that have adequate wet and dry elasticity and adequate absorbency, without prior use of expensive foam materials. The inventors of the present invention have also found that they can change these properties by combining the elastic material of co-molding with other materials to obtain improved elasticity and absorbent properties.

The present invention provides an absorbent composite located in an absorbent article between the upper sheet and the lower sheet, the absorbent composite comprising a first receiving layer located between the upper sheet and the lower sheet and a retaining layer located between the upper sheet and the lower sheet, one of the first receiving layer and the retaining layer includes an elastic material of joint molding. When the first receiving layer includes co-resilient elastic material, the retaining layer includes one of the fluffed material / super absorbent polymer material of high density, hydrogen bonded, hydraulically bound material, composite material super absorbent polymer / adhesive and foam material. The absorbent composite may further include a distribution layer located between the upper sheet and the lower sheet, the distribution layer including one of the meltblown microfiber material, hydraulically entangled material, and foam material.

The present invention also provides an absorbent composite located in an absorbent article between the upper sheet and the lower sheet, wherein the absorbent composite includes a first receiving layer including one of a co-molding material, an elastic co-molding material, an air-laid material (referred to as a dry-air molding material), a material web connected by carding (BCW) and foam, and a retaining layer located between the upper sheet and the lower sheet, and The louvre layer includes one of co-molding material, elastic co-molding material and air-laid material (dry-air molding material), fluffy material / super absorbent polymer material with high density, hydrogen bonds, hydraulically bound material, composite material super absorbent polymer / adhesive and foam material moreover, one of the first receiving layer and the retaining layer includes an elastic material co-molding.

The present invention also provides an absorbent composite located in an absorbent article between the upper layer and the lower layer, wherein the absorbent composite includes a first receiving layer including elastic co-molding material and a retaining layer located between the upper sheet and the lower sheet, the holding layer comprising one of co-molding material, co-forming elastic material, air-laid material (dry-air molding material), fluffed material / s high density hydrogen permeable polymer material, hydrogen bonded, hydraulically bound material, super absorbent polymer / adhesive composite material and foam material.

The present invention also provides an absorbent personal care product having an upper sheet and a lower sheet, the product including an absorbent composite located between the upper sheet and the lower sheet, the absorbent composite including a first receiving layer including an elastic joint molding material, and a retaining layer located between the upper a sheet and a bottom sheet, wherein the retaining layer includes one of co-molding material, an elastic co-molding material laid in air material, fluffy material / superabsorbent polymer material with a high density, with hydrogen bonds, hydraulically bound material, a composite material superabsorbent polymer / adhesive and foam material.

The present invention also provides a method for making an absorbent personal care product having an absorbent composite, the method comprising combining a stream of absorbent material with a stream of meltblown fibers to form a composite stream; picking up the composite flow on the forming surface with the formation of an elastic non-woven fabric co-molding; and combining the elastic non-woven fabric co-molding with the top sheet and the bottom sheet

The present invention also provides an absorbent composite adapted for use in an absorbent article having a top sheet and a bottom sheet, wherein the absorbent composite includes a receiving layer including foam material disposed between the upper sheet and the lower sheet, the receiving layer having a plurality of openings therein and holding a layer located between the upper sheet and the lower sheet, while the retaining layer includes an elastic material co-molding.

Other features and objects of the present invention are described in more detail here.

BRIEF DESCRIPTION OF THE DRAWINGS

The above-described and other features and objects of the present invention and the method for their preparation will become more clear, and the invention itself will be more clear with reference to the following description, the accompanying claims and the accompanying drawings.

Figure 1 is a schematic view of one object of a method for forming a web of joint molding according to the present invention;

FIG. 2 is a depiction of specific elements of the device shown in FIG. one;

FIG. 3 is a cross-sectional view of one object of a textured non-woven fabric of co-molding formed in accordance with the present invention;

FIG. 4 is a photograph of one object of a textured non-woven fabric co-molding;

FIG. 5 is a photograph of the co-formed textured nonwoven webs of FIG. 4 after crushing and subsequent loosening;

FIG. 6 is a photograph of another object of a co-formed non-woven fabric;

FIG. 7 is a photograph of the co-formed textured nonwoven webs of FIG. 6 after crushing and subsequent loosening;

FIG. 8 is a schematic partial cutaway top view of a feminine hygiene product comprising an absorbent composite of the present invention;

FIG. 9 is a partially schematic side view of a feminine hygiene product comprising an absorbent composite of the present invention;

10 is a schematic top view of an example of a contour of a pattern of holes on an absorbent composite used in testing an absorbent composite of the present invention; and

FIG. 11 is a schematic top view of an example of an absorbent composite loop used in testing the absorbent composite of the present invention.

The reuse of the reference numerals in the present description and in the drawings is intended to mean the same or similar features or elements of the present invention.

DETAILED DESCRIPTION

The person skilled in the art should understand that the present description is a description of only exemplary objects and is not intended to limit the wider objects of the present invention.

Reference will now be made in more detail to various objects of the invention, one or more examples of which are given here below. Each example is provided to illustrate and not limit the invention. Indeed, one skilled in the art will recognize that various modifications and variations can be made in the present invention without departing from the scope and spirit of the invention. For example, elements shown or described as part of one object can be used in another object to obtain another additional object. Thus, it should be understood that the present invention covers such modifications and variations.

As used herein, the term “nonwoven fabric” generally refers to a fabric having the structure of individual fibers or threads that are intertwined but not identifiable, as in a woven fabric. Examples of non-woven fabric or webs include meltblown webs, spunbond webs, carded webs, air-formed webs, co-formed webs, hydraulically entangled webs, etc., but are not limited to.

As used herein, the term "spunbond web" generally refers to a web containing substantially continuous, small diameter fibers. Fibers are formed by extruding molten thermoplastic material through a variety of small, usually round capillaries of a die with a diameter of rapidly contracting extruded fibers, for example, eductive drawing and / or other known spinneret mechanisms. The production of a web made by a spinneret manufacturing process is described and shown, for example, in Patents CUT A No. 4,340,563 Appel et al., 3,692,618 Dorshner et al. 3,802,817 Matsuki et al. 3,338,992 Kinney 3,341,394 Kinney 3,502,763 Hartman 3,502,538 Levy 3,542,615 Dobo et al. And 5,382,400 Pike et al. here by reference for all purposes. Fibers made by the spinneret manufacturing process are generally not sticky when applied to a collecting surface. Fibers made by the spinneret manufacturing process have a diameter of less than about 40 micrometers, and often range from about 5 to about 20 micrometers.

Generally speaking, the present invention is directed to an absorbent composite having an elastic co-molding layer and possibly at least one or more additional layers. The co-molding elastic layer, as described in more detail below, is formed from an elastic non-woven co-molding fabric that contains a meltblown matrix fibers and absorbent material. Absorbent composite can be used in personal care products or other suitable products.

As one example, an absorbent composite can be used as an absorbent element in a feminine hygiene product. As shown in FIG. 8, the feminine hygiene article 70 includes a peelable strip 72 that adheres adhesively to the garment-facing side of the bottom sheet 76, on one side by means of adhesive 74 for attaching to garment. The other side of the bottom sheet 76 is attached to the absorbent layer 78 using structural adhesive.

The absorbent layer 78 is attached to the lining on the body side or to the top sheet 80. The absorbent composite 84 of the present invention can suitably replace the absorbent layer 78. Preferably, the use of the absorbent composite 84 will prevent wrinkling of the product when worn, and therefore improve overall performance and reduce leaks. Other suitable configurations for forming absorbent personal care products with absorbent core materials are well known to those skilled in the art. In one preferred aspect, the absorbent composite 84 has a textured surface. The textured surface is preferably located in the direction of the topsheet 80 in order to facilitate faster fluid intake and higher absorbency of the absorbent core.

The absorbent composite 84 of the present invention, located between the top sheet 80 and the liquid impermeable bottom sheet 76, includes one to three layers in addition to the resilient co-molding material. As shown in FIG. 9, the absorbent composite 84 may include an optional first liquid receiving layer 86, an optional second liquid receiving layer 88, or an optional first distribution layer 90, a retaining layer 94, and an optional second distribution layer 96. These layers are generally face-to-face. with absorbent composite 84.

In various objects of the present invention, the first receiving layer 86 may be wider and / or longer than the retaining layer 94 or may be shaped different from a rectangular one to better fit the body when worn. In another aspect of the present invention, a layer that includes resilient co-molding material may be the widest and / or longest layer. In yet another aspect of the present invention, a layer that includes air-laid material may be the widest and / or longest layer.

At least one of the first receiving and holding layers 86, 94 includes a co-resilient material that can function as a liquid receiving material or as a liquid holding material, respectively. For an object in which the first receiving layer 86 includes co-forming elastic material, the absorbent composite 84 includes an additional layer, which may be a second liquid receiving layer 88, a first distribution layer 90, a holding layer 94, or a second distribution layer 96. For an object in which the holding layer 94 includes an elastic co-molding material, the absorbent composite 84 includes an additional layer, which may be a first liquid receiving layer 86, a second liquid receiving layer 88, p the first distribution layer 90 or the second distribution layer 96.

The materials included in each layer are described in more detail below. The first receiving layer 86 may include co-molding material, resilient co-molding material, air-laid material, carded bonding material (BCW) or foam, and may further include fluff pulp. The second fluid receiving layer 88 may include carded material, air-laid material or foam. The first distribution layer 90 may include hydraulically entangled material, meltblown microfiber material or foam material. The retaining layer 94 may include co-molding material, resilient co-molding material, or air-laid material, each of which may further include super absorbent material (SAM). The retaining layer 94 may, instead, include a fluffy, super absorbent, high density polymer material with hydrogen bonds, a hydraulically bound material, a super absorbent polymer / adhesive composite material or a foam material. Any of these retention layer materials may further include fluff pulp. Finally, the second distribution layer 96 may include meltblown microfiber material, hydraulically entangled material or foam material, and further may include fluff pulp.

The absorbent composite 84 of the present invention can be used in a wide variety of products. For example, the absorbent composite 84 may be incorporated into an absorbent article that can absorb water or other liquids. Examples of such absorbent articles include personal care absorbent articles such as diapers, training pants, absorbent underwear, incontinence products, feminine hygiene products (e.g., sanitary napkins), swimwear, baby wipes, absorbent gloves, etc. ;

medical absorbent products such as clothing, sheets with a dedicated surgical field, absorbent sheets, bed sheets, bandages, absorbent surgical sheets and medical napkins; napkins for catering; clothing products; sachet; etc., but are not limited to. Materials and processes suitable for forming such articles are well known to those skilled in the art. Some examples of such absorbent articles are described in US Pat. No. 5,649,916 to DiPalma et al .; US 6,110,158, Kielpikowski; US 6,663,611, Blaney et al., Which are incorporated herein by reference, in full, for all purposes. Other suitable products are described in US Patent Application No. 2004/0060112 A1, Fell et al., Also in US Patent No. 4,886,512 Damico et al .; 5,558,659 Sherrod et al .; 6,888,044 Fell et al .; and 6,511,465 Freibwger et al., all of which are incorporated herein by reference for all purposes. When used in an absorbent article, the absorbent composite 84 of the present invention can form an absorbent core component or any other absorbent component of an absorbent article well known in the art.

The term “co-molding material” refers to a mixture of meltblown fibers and absorbent fibers, such as cellulosic fibers, that can be formed by air-forming a meltblown polymer material while simultaneously blowing suspended fibers in an air stream into the meltblown stream fibers. Co-molding material may also include other materials, such as superabsorbent materials. Melt-blown fibers and absorbent fibers (and other possible materials) are collected on a forming surface, such as provided by a mesh tape (with holes). The forming surface may include gas-permeable material that has been placed on the forming surface. Co-molding materials are further described in US Pat. Nos. 5,508,102 and 5,350,624 by Georger et al., And in US 4,100,324, Anderson, which are incorporated herein by reference to the extent which do not contradict what is indicated here.

As used here, the term “elastic co-molding material” generally refers to an elastic non-woven co-molding layer comprising a matrix of meltblown fibers and an absorbent material, wherein the meltblown fibers comprise from 30 weight% to about 99 weight% the web, and the absorbent material is from about 1 weight% to about 70 weight% of the web, and in addition, the melt blown by the fiber is formed from a thermoplastic composition that contains at least one copolymer of polypropylene and α-olefin, having a propylene content of from about 60 mol% to about 99.5 mol%, and an α-olefin content of from about 0.5 mol% to about 40 mol%, the copolymer additionally having a density of from about 0.86 to about 090 grams per cubic centimeter, and the composition has a melt flow rate of from about 120 to about 6000 grams in 10 minutes, determined at 230 ° C. in accordance with ASTM Test Method D 123 8-E, although for practical reasons the upper limit of the flow rate range can be reduced melt.

The fibers of the co-molded material blown from the melt comprise from 30 wt.% To about 99 wt.% Of the web and the absorbent material is from about 1 wt.% To about 70 wt.% Of the web. More preferably, the meltblown fibers of the co-formed non-woven fabric comprise from 45% to about 99% by weight of the fabric, and the absorbent material is from about 1% to about 55% by weight of the fabric. The meltblown fibers are formed from the thermoplastic composition described below, which contains at least one copolymer of propylene and α-olefin with a specific monomer content, density, melt flow rate, etc. The selection of a particular type of propylene copolymer and α-olefin provides a final composition with improved thermal properties to form a co-formed web. For example, the thermoplastic composition crystallizes at a relatively low rate, thereby allowing the fibers to remain slightly sticky during formation. This stickiness can provide many advantages, such as increasing the ability of meltblown fibers to adhere to the absorbent material during web formation. The meltblown fibers may be from 30 weight% to about 99 weight%, in particular embodiments from about 45 weight% to about 99 weight%, and in more specific embodiments, from about 50 weight% to about 90 weight%, and in even more preferred embodiments, from about 50 weight% to about 80 weight% of the co-molded web. Thus, the absorbent material can be from about 1 weight% to about 70 weight%, in specific embodiments, from 1 weight% to about 55 weight%, and in more specific embodiments, from 10 weight% to about 50 weight%, and even more preferred embodiments, from about 20% to about 50% by weight of the co-molded web.

In addition to increasing the bonding ability of meltblown fibers, the thermoplastic composition of the present invention can also provide other benefits to the resulting co-molded structure. In some embodiments, for example, a co-molding web may be endowed with a texture using a three-dimensional forming surface. In such embodiments, the relatively low crystallization rate of the meltblown fibers can increase their ability to match the contours of a three-dimensional forming surface. From the moment of crystallization of the fibers, however, the fibers blown from the melt can achieve a degree of elasticity greater than that of conventional polypropylene, thereby allowing them both to retain and restore a three-dimensional shape, and a highly textured surface on a fabric formed by co-molding.

Another advantage of the increased stickiness of the fibers during formation may be the increased strength of the adhesion of the layers between the layers of the multilayer non-woven dense co-molding, leading to additional deformation energy which is necessary for the delamination of the layers. Such increased layer attachment strength can reduce or eliminate the need for embossing, which could adversely affect sheet characteristics such as thickness and density. Increased layer attachment strength may be particularly preferred during dispensing of towels made from a multi-layered non-woven fabric of co-molding. A texture formed using a three-dimensional forming surface as described herein can further increase the adhesion strength of the layers by increasing the area of the contact surface between the layers.

Various embodiments of the present invention will now be described in more detail.

The thermoplastic composition of the present invention contains at least one copolymer of propylene and an α-olefin, such as a C ₂ -C ₂₀ α-olefin, a C ₂ -C ₁₂ α-olefin and a C ₂ -C ₈ α-olefin. Suitable α-olefins may be linear or branched (for example, one or more C ₁ -C ₃ alkyl branches, or an aryl group). Specific examples include ethylene, butene; 3-methyl-1-butene; 3,3-dimethyl-1-butene; pentene; pentene with one or more methyl, ethyl or propyl substituents; hexene with one or more methyl, ethyl or propyl substituents; heptene with one or more methyl, ethyl or propyl substituents; octene with one or more methyl, ethyl or propyl substituents; nonen with one or more methyl, ethyl or propyl substituents; ethyl, methyl or dimethyl substituted decene; dodecene; styrene; and so on. Particularly preferred α-olefin comonomers are ethylene, butene (e.g. 1-butene), heptene and octene (e.g. 1-octene or 2-octene). The propylene content of such copolymers may be from about 60 mol% to about 99.5 mol%, in other embodiments, from about 80 mol% to about 99 mol%, and in some embodiments, from about 85 mol% to about 98 mol%. The content of α-olefin may also be in the range from about 0.5 mol.% To about 40 mol.%, In other embodiments, from about 1 mol.% To about 20 mol.%, And in some embodiments, from about 2 mol. % to about 15 mol.%. The distribution of the α-olefin comonomer is usually random and uniform among the molecular weight fractions forming the propylene copolymer.

The density of the copolymer of propylene and α-olefin may be a function of both the length and the amount of α-olefin. Thus, the greater the length of the α-olefin and the greater the amount of α-olefin is present, the lower the density of the copolymer. In general, copolymers with a higher density are better able to form three-dimensional structures, while copolymers with a lower density have better elastomeric and elastic properties. Thus, in order to achieve the optimal balance between texture and elasticity, the copolymer of propylene and α-olefin is usually chosen so that it has a density of about 0.860 grams per cubic centimeter (g / cm ³ ) to about 0.900 g / cm ³ , in other embodiments from about 0.861 to about 0.890 g / cm ³ , and in still other embodiments, from about 0.862 g / cm ³ to about 0.880 g / cm ³ . In addition, the density of the thermoplastic composition is usually chosen so as to have a density of about 0.860 grams per cubic centimeter (g / cm ³ ) to about 0.940 g / cm ³ , in other embodiments, from about 0.861 to about 0.920 g / cm ³ , and in still other embodiments, from about 0.862 g / cm ³ to about 0.900 g / cm ³ .

Any of a variety of known manufacturing methods can typically be used to form a copolymer of propylene and an α-olefin used in meltblown fibers. For example, olefin polymers can be formed using a free radical or a complex catalyst (e.g., Ziegler-Natta). Preferably, the copolymer is formed from a complex catalyst with a single polymerization center, such as a metallocene catalyst. Such a catalyst system produces propylene copolymers in which the comonomer is randomly distributed within the molecular unit and evenly distributed among fractions with different molecular weights. Propylene copolymers catalyzed by a metallocene catalyst are described, for example, in US Pat. No. 7,105,609 to Datta et al .; 6,500,563 Datta et al .; 5539056 Yang et al .; and 5,596,052 to Resconi et al., which are incorporated herein by reference for all purposes. Examples of metallocene catalysts include bis (n-butylcyclopentadienyl) titanium dichloride, bis (n-butylcyclopentadienyl) zirconium dichloride, bis (cyclopentadienyl) scandium chloride, bis (indenyl) zirconium dichloride, bis (methylcyclopentadienyl) titanium dichloropentenyl, bis (methyl) cobaltocene, cyclopentadienyl titanium trichloride, ferrocene, hafnocene dichloride, isopropyl (cyclopentadienyl, -1-fluorenyl) zirconium dichloride, molybdocene dichloride, nickelocene, niobocene dichloride, rutenocene, titanocene dichloride, zirconocide irkonocene dichloride, and so on. Polymers made using metallocene catalysts typically have a wide range of molecular weights. For example, metallocene-catalyzed polymers may have polydisperse numbers (Mw / Mn) less than 4, a controlled distribution of branching of short units, and a controlled symmetry of the molecular structure.

In specific embodiments, the propylene-α-olefin copolymer is about 50 wt.% Or more, in additional embodiments, about 60 wt.% Or more, and in other embodiments, about 75 wt.% Or more of the thermoplastic composition used for the formation of meltblown fibers. In other embodiments, a copolymer of propylene and α-olefin is at least about 1 wt.% And less than about 49 wt.%, In specific embodiments, from at least about 1 wt.% And less than about 45 wt.% , in additional embodiments, from at least about 5 wt.% and less than about 45 wt.%, and in still other embodiments, from at least about 5 wt.% and less than about 35 wt.% thermoplastic composition, used to form meltblown fibers. Of course, other thermoplastic polymers can also be used to form meltblown fibers, as long as they do not adversely affect the desired properties of the composite. For example, meltblown fibers may contain other polyolefins (e.g. polypropylene, polyethylene, etc.), polyesters, polyurethanes, polyamides, block copolymers, etc. In one embodiment, meltblown fibers may comprise an additional propylene polymer, such as a homopolypropylene or a propylene copolymer. The additional propylene polymer may, for example, be formed from a substantially isotactic polypropylene homopolymer or copolymer containing equal to or less than about 10 weight percent of another monomer, i.e. at least about 90% by weight of propylene. Such polypropylene may be present in the form of a grafted, random or block copolymer and may be predominantly crystallized, since it has a sharp melting point above about 110 ° C, in other embodiments, above about 115 ° C, and in yet other embodiments, above about 130 ° C. Examples of such additional polypropylenes are described in US Pat. No. 6,992,159 to Datta et al., Which is incorporated herein by reference for all purposes.

In specific embodiments, the additional polymer (s) may be from about 0.1 wt.% To about 90 wt.%, In additional embodiments, from about 0.5 wt.% To about 50 wt.%, And in other embodiments, from about 1 wt.% To about 30 wt.% Thermoplastic composition. Thus, the above copolymer of propylene and α-olefin may be from about 15 wt.% To about 99.9 wt.%, In other embodiments, from about 50 wt.% To about 99.5 wt.%, And still in some embodiments, from about 70 wt.% to about 99 wt.% thermoplastic composition.

The thermoplastic composition used to form the meltblown fibers may also contain other additives well known to those skilled in the art, such as surfactants, melting stabilizers, processing stabilizers, heat stabilizers, light stabilizers, antioxidants, thermal aging stabilizers, whitening agents, etc. Phosphite stabilizers (eg, IRGAFOS, commercially available from Ciba Specialty Chemicals of Tarrytown, New York and DOVERPHOS, commercially available from Dover Chemical Corp.of Dover, Ohio) are examples of melting stabilizers. In addition, sterically hindered amine stabilizers (e.g., CHIMASSORB, commercially available from Ciba Specialty Chemicals) are examples of heat and light stabilizers. In addition, sterically hindered phenols are widely used as antioxidants. Some suitable sterically hindered phenols include those commercially available from Ciba Specialty Chemicals (Ciba) under the brand name Irganox®, such as Irganox® 1076, 1010 or E 201. When used, such additives (eg, antioxidants, stabilizers, surfactants etc.) may each be present in an amount of from about 0.001 wt.% to about 15 wt.%, in other embodiments, from about 0.005 wt.% to about 10 wt.%, and in still other embodiments, from about 0.01 wt.% To about 5 wt.% Of the thermoplastic composition used to form the blow meltable fibers One or more surfactants may be added to the polymer composition to impart greater wettability to the polymer fibers and to improve the fluid receiving properties of the co-molded material. Suitable surfactants include cationic, anionic, amphoteric and nonionic surfactants More specifically, a suitable internal surfactant commercially available from Ciba is IRGASURF HL 560. When used ii, a surfactant may be present in an amount of from about 0.5 wt.% to about 10 wt.%, in the following embodiments, from about 1.0 wt.% to about 7.5 wt.%, and even in subsequent embodiments, from about 1.5% by weight to about 5% by weight of a thermoplastic composition used to form meltblown fibers. Surfactants can also be applied to meltblown fibers from the outside as a topical treatment.

By selecting some polymers and their contents, the resulting thermoplastic composition may have thermal properties greater than the polypropylene homopolymers traditionally used in meltblown webs. For example, a thermoplastic composition is usually more amorphous in nature than polypropylene homopolymers traditionally used in meltblown webs. For this reason, the crystallization rate of the thermoplastic composition is lower than that measured by its “crystallization half-life" —that is, the time required for half the material to become crystalline. For example, a thermoplastic composition typically has a crystallization half-life of more than about 5 minutes, in other embodiments, from about 5.25 minutes to about 20 minutes, and even in others, from about 5.5 to about 12 minutes, determined at a temperature of 125 ° C. In the opposite sense, traditional polypropylene homopolymers often have a crystallization half-life of 5 minutes or less. In addition, the thermoplastic composition may have a melting point ("T _p ") from about 100 ° C to about 250 ° C, in additional embodiments, from about 110 ° C to about 200 ° C, and even in other embodiments, from about 140 ° C to about 180 ° C. The thermoplastic composition may also have a crystallization temperature ("T _k ") (determined at a cooling rate of 10 ° C / min) from about 50 ° C to about 150 ° C, in other embodiments, from about 80 ° C to about 140 ° C, and in other embodiments, from about 100 ° C to about 120 ° C. The crystallization half-life, melting point, and crystallization temperature can be determined using differential scanning calorimetry ("DSC"("DSC")) well known to specialists in this field of technology.

The melt flow rate of the thermoplastic composition can also be selected within a certain range to optimize the properties obtained as a result of meltblown fibers. The melt flow rate is the weight of the polymer (in grams) that can be passed through the measuring hole of the extrusion plastomer (2.09 mm (0.0825 in.) Diameter) when exposed to 2160 grams for 10 minutes at 230 ° C. Generally speaking, the melt flow rate is high enough to improve the melt processability, but not so high as to adversely affect the binder properties of the fibers for the absorbent material. Thus, in most embodiments of the present invention, the thermoplastic composition has a melt flow rate of from about 120 to about 6,000 grams in 10 minutes, in other embodiments, from about 150 to about 3,000 grams in 10 minutes, and in other embodiments, from about 170 to about 1,500 grams in 10 minutes, measured in accordance with the testing method D1238-E of the American society for testing materials (ASTM Test Method D1238-E).

The term “meltblown fibers” refers to fibers formed by extruding molten thermoplastic material through a variety of thin, usually round, capillaries of a spinneret in the form of molten filaments or fibers into a high-speed, usually heated stream of gas (eg, air) that thins the fibers of the molten thermoplastic material to reduce their diameter. In the particular case of the co-molding process, the meltblown fiber stream intersects with one or more material streams that are introduced from a different direction. Then the meltblown fibers and other materials are transferred using a high-speed gas stream and placed on a collecting surface. The distribution and orientation of the meltblown fibers within the formed web depends on the geometry and process conditions. Under certain process and equipment conditions, the resulting fibers can be substantially “continuous,” formed with several separations, damaged fibers, or tapering ends if multiple regions are examined through a microscope at 10x or 20x magnification. When “continuous” meltblown fibers are obtained, the sides of the individual fibers will generally correspond to minimal changes in fiber diameter within the length of the individual fiber. On the contrary, under other conditions, the fibers may be excessively elongated and the strands may be damaged and form a series of irregular, individual fiber lengths and many damaged ends. The contraction of an already thinned damaged fiber often leads to polymer sticking. Such a process is disclosed, for example, in US Pat. No. 3,849,241 to Butin et al., Which is incorporated herein by reference in such a way as not to conflict with what is indicated here.

Fibers blown from the melt can be single-component or multi-component. Multicomponent fibers are usually formed from a polymer or a mixture of polymers extruded from a single extruder. Multicomponent fibers are typically formed from two or more polymers (e.g., bicomponent fibers) extruded from separate extruders. The polymers can be located in essentially permanently located, distinct areas along the cross-section of the fibers. The components can be arranged in any preferred configuration, such as a shell-core, side-to-side, slice, islet, three islets, a bull's eye, or many other arrangements known in the art. Many methods for forming multicomponent fibers are described in US Pat. and 6,200,669 to Marmon et al., which are incorporated herein by reference for all purposes. Multicomponent fibers having various irregular shapes can also be formed, as described in US Patent Nos. 5,277,976 to Hogle et al., 5,162,074 Hills, 5,466,410 Hills, 5,069,970 to Largman et al., And 5,057,368 to Largman et al., Which are incorporated herein by reference for all purposes. It should be noted that meltblown materials are typically treated with a wetting agent for such applications as described herein. Any suitable wetting treatment may be used.

Any absorbent material can typically be used in a co-formed non-woven fabric, such as absorbent fibers, particles, etc. In one embodiment, the absorbent material includes fibers formed by a variety of pulp processing processes, such as kraft pulp, sulfite pulp, thermomechanical pulp, etc. The pulp fibers may include softwood fibers having an average fiber length of more than 1 mm and in particular from about 1.5 to 5 mm of weighted average length. Such softwood fibers may include, but are not limited to, northern softwood, southern softwood, mahogany, Virginian juniper, Canadian spruce (tsuga), pine (e.g., southern pine), spruce (e.g., black spruce), combinations thereof, etc. Exemplary, commercially available pulp fibers suitable for the present invention include fibers available from Weyerhaeuser Co. of Federal Way, Washington under the designation "Weyco CF-405." Hardwood fibers such as eucalyptus, maple, birch, aspen, and so on can also be used. In some cases, eucalyptus fibers may be especially desirable to increase the softness of the fabric. Eucalyptus fibers can also improve brightness, increase opacity, and alter the pore structure of the web to increase its absorbency. Moreover, if necessary, recycled fibers from recycled materials can be used, such as fiber pulp from sources such as newsprint, recycled cardboard, and office waste. In addition, other natural fibers can also be used in the present invention, such as manila hemp, sabai grass, milkweed fibers, pineapple leaf, and so on. In addition, in some cases, synthetic fibers may also be used.

In addition to or in combination with pulp fibers, the absorbent material may also include super absorbent material in the form of fibers, particles, gels, etc. In general, superabsorbent materials are water-swellable materials having an absorbency of at least about 10 times their weight, at least about 20 times their weight, or at least about 30 times their weight in aqueous solutions containing 0.9 weight percent sodium chloride . Super absorbent material can be formed from natural, synthetic and modified natural polymers and materials. Examples of synthetic superabsorbent polymers include materials including a weak crosslinked polymer that absorbs neutralized acidic water and a weakly crosslinked polymer that absorbs neutralized water, as disclosed in US Pat. No. 6,623,576, Mitchell, etc. In addition, examples include alkali metals and salts. ammonium polyacrylic acid and polymethacrylic acid, polyacrylamides, polyvinyl esters, copolymers of maleic anhydride with vinyl esters and alpha-olefins, polyvinylpyrrolidone, polyvinyl orfolinon, polyvinyl alcohol, and mixtures and copolymers thereof. In addition, superabsorbent materials include natural or modified natural polymers, such as hydrolyzed acrylonitrile grafted copolymerized starch, grafted acrylic acid starch, methyl cellulose, chitosan, carboxymethyl cellulose, hydroxypropyl cellulose, and natural gum resins such as tree and so on. Mixtures of natural and fully or partially synthetic superabsorbent polymers can also be used in the present invention. Particularly suitable superabsorbent polymers are HYSORB 8800AD superabsorbent superabsorbent (available from BASF of Charlotte, North Carolina and FAVOR SXM 9300 superabsorbent superabsorbent (commercially available from Evonik Stockhausen Greensboro, North Carolina).

The co-molding web of the present invention is typically fabricated by a process in which at least one melt-blown extrusion die (e.g., two) is located adjacent to a groove through which absorbent material is added during web formation. Some examples of such a co-molding technique are described in US Pat. No. 4,100,324 to Anderson et al .; 5350624 Georger et al .; and 5508102 Georger and others, also in US Patent Applications No. 2003/0200991 to Keck and others, and 2007/0049153 to Dunbar and others, all of which are incorporated herein by reference for all purposes.

Referring to FIG. 1, for example, one embodiment of a device is shown for forming a joint shaped web of the present invention. In this embodiment, the device includes a pellet bin 12 or 12 ′ of the extruder 14 or 14 ′, respectively, into which a propylene / α-olefin thermoplastic composition can be placed. The extruders 14 and 14 'each have a compression screw (not shown) that is driven by a conventional drive motor (not shown). As the polymer advances through the extruders 14 and 14 ', it is gradually heated to a molten state by rotating the compression screw using a drive motor. Heating can be performed at many separate stages with its temperature gradually rising as it moves through the separate heating zones of the extruders 14 and 14 'in the direction of the two heads blowing out of the melt 16 and 18, respectively. The meltblown heads 16 and 18 may already be another heating zone, where the temperature of the thermoplastic resin is maintained at an elevated level for extrusion.

When using two or more meltblown heads, as described above, it should be understood that the fibers produced from the individual heads can be of different types. Thus, one or more of the size, shape, or polymer composition may differ, and in addition, the fibers may be unicomponent or multicomponent fibers. For example, large fibers can be produced using the first head, such that they have an average diameter of about 10 micrometers or more, in other embodiments, about 15 micrometers or more, and in other embodiments, from about 20 to about 50 micrometers, while smaller fibers can be produced using a second head, such as having an average diameter of about 10 micrometers or less, in other embodiments, about 7 micrometers or less, and in other embodiments, from about 2 to about 6 micrometers. In addition, it may be preferable that each die extrudes approximately the same amount of polymer, so that the relative percentage of the base weight of the co-formed non-woven fabric material arising from each melt-blowing die is substantially the same. Alternatively, it may also be preferable to have a relative base weight of the product asymmetric, so that one head or the other is responsible for most of the jointly formed web in terms of base weight. As a specific example, for a meltblown fiber-based nonwoven fabric having a base weight of 1.0 ounce per square yard or “osy” (34 grams per square meter or “gsm”), for the first meltblown head, it may be preferable produce about 30 percent of the base weight of the meltblown, formed from fibers, nonwoven fabric, while one or more subsequent meltblown heads produce the remaining 70 percent of the meltblown, would be formed from fibers of the nonwoven web material. Generally speaking, the total base weight of the co-formed non-woven fabric is from about 10 g / m ² to about 350 g / m ² , and more particularly from about 17 g / m ² to about 200 g / m ² , and even more specifically from about 25 g / m ² to about 150 g / m ² .

Each meltblown head 16 and 18 is configured so that two streams of thinning gas converge to the head to form one gas stream that entrains and thins the molten strands 20 as they exit the small holes or channels 24 in each meltblown head. The molten filaments 20 form fibers or, depending on the degree of thinning, microfibers, of a small diameter, which is usually less than the diameter of the channels 24. Thus, each meltblown head 16 and 18 has a corresponding single gas stream 26 and 28 containing captured thermoplastic polymer fibers . Gas streams 26 and 28 containing polymer fibers are aligned to converge in the contact zone 30. Usually, the meltblown heads 16 and 18 are located at a certain angle relative to the forming surface, as described in US Patents Nos. 5,508,102 and 5,350,624 to Georger et al. Referring in FIG. 2, for example, heads 16 and 18 blowing out of the melt can be oriented at an angle a, as measured from plane “A”, tangentially to two heads 16 and 18. As shown, plane “A” is usually parallel to forming surface 58 (FIG. . one). Typically, each head 16 and 18 is installed at an angle in the range from 30 to about 75 degrees, in other embodiments, from about 35 ° to about 60 °, and in additional embodiments, from about 45 ° to about 55 °. The heads 16 and 18 can be oriented at the same time and at different angles. In fact, the texture of the co-formed web can really be improved by orienting one head at an angle different from the other head.

Referring again to FIG. 1, absorbent fibers 32 (eg, fluff pulp fibers) are added to two streams 26 and 18 of thermoplastic polymer fibers 20 and 21, respectively, and in the contact zone 30. Introduction of absorbent fibers 32 into two streams 26 and 28 of thermoplastic polymer fibers 20 and 21 respectively, made to produce a gradual distribution of absorbent fibers 32 within the combined streams 26 and 28 of thermoplastic polymer fibers. This can be accomplished by merging a secondary gas stream 34 containing absorbent fibers 32 between two streams 26 and 28 of thermoplastic polymer fibers 20 and 21, so that all three gas streams converge in a controlled manner. Due to the fact that they remain relatively sticky and half-melted after formation, the fibers 20 and 21 blown from the melt can simultaneously adhere and tangle with the absorbent fibers 32 upon contact between them, with the formation of a coherent non-woven structure.

To achieve fiber combining, any conventional equipment can be used, such as a rotary roller with teeth 36, having a plurality of teeth 38 adapted to separate sheets or webs 40 of absorbent fibers into separate absorbent fibers. In use, sheets or canvases 40 of fibers 32 are fed into a rotating roll with teeth 36 using a roll tool 42. After the teeth 38 of the rotating roll with teeth 36 divide the fiber sheet into separate absorbent fibers 32, the individual fibers are transported towards the thermoplastic polymer flow fibers through the nozzle 44. The housing 46 includes a rotating roller with teeth 36 and provides a feed channel or slot 48 between the housing 46 and the surface of the teeth 38 of the rotating roller with teeth 36. Gas, for example, air, is supplied to the channel at the supply or slot 48 between the surface of the rotating roll with teeth 36 and the housing 46 using the gas channel 50. The gas channel 50 may enter the supply channel or slot 48 in the connection 52 of the nozzle 44 and the slot 48. Gas is supplied in sufficient quantity to use it as a medium for moving the absorbent fibers 32 through the nozzle 44. The gas supplied from the channel 50 also serves as an aid in removing the absorbent fibers 32 from the teeth 38 of the rotating roll with teeth 36. The gas can be supplied using any conventional I, such as, for example, an air blower (not shown). It is contemplated that additives and / or other materials may be added to or implicated in the gas stream to process absorbent fibers. The individual absorbent fibers 32 are typically moved through the nozzle 44 at approximately the speed at which the absorbent fibers 32 leave the teeth of the rotary roller with teeth 36. In other words, the absorbent fibers 32, until the teeth of the rotary roller with teeth 36 leave and enter the nozzle 44, usually maintain their speed both in value and in the direction from the point where they leave the teeth 38 of the rotating roll with teeth 36. Such a device is described in more detail in US Pat. No. 4,100,324 to Anderson et al.

If necessary, the speed of the secondary gas stream 34 can be adjusted to obtain structures formed by co-formation, with various properties. For example, when the speed of the secondary gas stream is adjusted so that it is greater than the speed of each stream 26 and 28 of the thermoplastic polymer fibers 20 and 21 prior to contact in the contact zone 30, the absorbent fibers 32 are included in the co-formed non-woven fabric in a gradient structure. Thus, the absorbent fibers 32 have a higher concentration between the outer surfaces of the non-woven fabric formed by joint molding than on the outer surfaces. On the other hand, when the speed of the secondary gas stream 34 is less than the speed of each stream 26 and 28 of the thermoplastic polymer fibers 20 and 21 prior to contact in the contact zone 30, the absorbent fibers 32 are included in the co-formed non-woven fabric 54 in a substantially homogeneous manner. Thus, the concentration of absorbent fibers is substantially the same throughout the co-formed non-woven fabric 54. This is due to the fact that the low-speed flow of absorbent fibers 32 is pulled into the high-speed flow of thermoplastic polymer fibers 20, 21 to improve turbulent mixing, which leads to uniform distribution absorbent fibers 32.

To convert the composite stream 56 of thermoplastic polymer fibers 20, 21 and absorbent fibers 32 into a co-formed non-woven structure 54, the collecting device is located in the path of the composite stream 56. The collecting device may be a forming surface 58 (for example, conveyor belt, drum, wire, material, etc.) driven by the rollers 60 and so that it rotates as shown by arrow 62 in FIG. 1. The combined streams of thermoplastic polymer fibers 20, 21 and absorbent fibers 32 are collected as a coherent matrix of fibers on the 'surface of forming surface 58 to form a co-formed non-woven fabric 54. If necessary, a vacuum chamber (not shown) can be used to assist in drawing proximal molten, meltblown fibers onto forming surface 58. The resulting textured, co-molded, non-woven structure 54 is co resistant and can be removed from the forming surface 58 as a self-supporting non-woven material.

It should be understood that the present invention is in no way limited to the above described embodiments. In alternative embodiments, for example, the first and second melt-blown heads can be used so that they extend substantially across the width of the forming surface in a direction that is substantially transverse to the direction of movement of the forming surface. The extrusion heads can thus be arranged in a substantially vertical position, that is, perpendicular to the forming surface, so that thereby the meltblown fibers are blown directly down onto the forming surface. Such a configuration is well known in the art and is described in more detail, for example, in U.S. Patent Application No. 2007/0049153 to Dunbar et al. In addition, although the above-described embodiments use a plurality of melt-blown extrusion heads to produce fibers of different sizes A single extrusion die can also be used. An example of such a process is described, for example, in US Patent Application No. 2005/0136781 to Lassig et al., Which is incorporated herein by reference for all purposes.

As indicated above, it is desirable in some cases to form a co-forming web that is textured. Referring again to FIG. 1, for example, one embodiment of the present invention uses a shaping surface 58, which is perforated in nature so that the fibers can be drawn out through the openings of the surface and form a bulky pile protruding from the surfaces of the material, which corresponds to the holes in the forming surface 58 The perforated surface can be provided with any material that provides sufficient openings for the penetration of certain fibers, such as a highly permeable forming wire. The geometry of the forming mesh and the processing conditions can be used to change the texture or pile of the material. The specific choice will depend on the desired peak size, shape, depth, "density" of the surface pile (that is, the number of peaks or pile per unit area), etc. In one embodiment, for example, the wire may have an open area of from about 35% to about 65%, in other embodiments, from about 40% to about 60%, and in other embodiments, from about 45% to about 55%. One example of a very open area of the forming surface is the FORMTECH ™ 6 forming grid manufactured by Albany International Co. of Albany, New York. Such a wire has a “grid number” of about six strips per six strips per square inch (about 2.4 by 2.4 strips per square centimeter), that is, as a result of about 36 perforations or “holes” per square inch (about 5.6 per square centimeter), and for this reason having the ability to form about 36 villi or peaks in the material per square inch (about 5.6 peaks per square centimeter). FORMTECH ™ 6 wire also has a bending diameter of about 1 millimeter of polyester, a trench diameter of about 1.07 millimeters of polyester, a nominal air permeability of about 41.8 m ³ / min (1475 ft ³ / min), a nominal thickness of about 0.2 centimeters (0.08 in) and an open area of about 51% Another example of a forming surface available from Albany International Co. is a FORMTECH ™ 10 forming grid that has a grid number of about 10 strips per 10 strips per square inch (about 4 by 4 strips per square centimeter), that is, as a result of about 100 perforations or “holes” per square inch (about 15.5 per square centimeter), and for this reason having the ability to form about 100 villi or peaks per square inch (about 15.5 peaks per square centimeter) in the material. Another suitable forming net is FORMTECH ™ 8, which has an open area of 47% and is also available from Albany International. Of course, other forming grids and surfaces (e.g., drums, plates, sheets, etc.) may be used. For example, the sheets can be used with recesses engraved on the surface so that the co-formed fibers fill the recesses to produce a pile that corresponds to the recesses. Recesses (nap) can be of various forms, including, but not limited to, circles, squares, rectangles, curls, grooves, lines, clouds and so on. Surface options may also include, but are not limited to, alternating braided patterns, alternating strand sizes, separation layers (e.g., silicones, fluorine-containing compounds, etc.), statically scattering treatments, and the like. Other suitable perforated surfaces that may be used are described in US Patent Application No. 2007/0049153 to Dunbar et al.

Regardless of the particular texturing method used, the pile formed by the meltblown fibers of the present invention can better retain the desired shape and surface contour. Namely, because the fibers blown out of the melt crystallize at a relatively low speed, they are soft until placed on the forming surface, which allows them to hang and fit in shape to the surface contours. After crystallization of the fibers, they can retain their shape and form a pile. The size and shape of the resulting pile depends on the type of forming surface used, the types of fibers located on it, the volume below the air vacuum wire used to deposit the fibers on and into the forming surface, and other relevant factors. For example, the pile may protrude from the surface of the material in the range from about 0.25 millimeters to at least about 9 millimeters, and in additional embodiments, from about 0.5 millimeters to about 3 millimeters. Generally speaking, the pile is filled with fibers and thereby has the desired elasticity, useful for wiping and cleaning.

In FIG. 3 is a cross-sectional view of a co-formed textured web 100 having a first outer surface 122 and a second outer surface 128. At least one of the outer surfaces 122, 128 has a three-dimensional surface texture. In FIG. 3, for example, the first outer surface 122 has a three-dimensional surface texture that includes a pile or peaks 124 extending upward from the plane of the co-formed material. One indicator of the magnitude of three-dimensionality in the textured outer surface (s) of the co-formed web 100 is the ratio of maximum to minimum, which is calculated as the ratio of the total thickness "T" divided by the depth of the depressions "D". When texturing in accordance with the present invention, the co-formed web 100 typically has a maximum to a minimum ratio of about 5 or less, in other embodiments, from about 0.1 to about 4, and in additional embodiments, from about 0.5 to about 3. Quantity and distribution pile 24 can vary greatly depending on the desired end use. In specific embodiments that are more densely textured, the textured, co-molded web 100 will have from about 2 and about 70 villi 24 per square centimeter, and in other embodiments, from about 5 and 50 villi 24 per square centimeter. In some embodiments that are less densely textured, the textured, co-formed web 100 will have from about 100 to about 20,000 villi per square meter, and in other embodiments, will have from about 200 and 10,000 villus per square meter. The textured, co-molded web 100 may also exhibit a three-dimensional structure on the second surface of the web 120. This will be especially the case for materials with a lower base weight, such that have a base weight of less than 70 grams per square meter due to “mirroring”, however, the second surface of the material shows the offset of the peaks or between peaks on the first outer surface 122 of the material. In this case, the depth of the troughs D is measured for both outer surfaces 122, 128, as described above, and is added together to determine the total depth of the troughs of the material.

The co-molding material of the present invention may be better understood with reference to the following test methods and co-molding examples.

Test methods for co-molding material

Melt flow rate:

The melt flow rate ("MFR") is the weight of the polymer (in grams) passed through the outlet of the extrusion rheometer (0.0825 inch diameter) when exposed to 2160 grams in 10 minutes at 230 ° C. Unless otherwise indicated, the melt flow rate was measured in accordance with ASTM Test Method D 123 8-E.

Thermal properties:

Melting point and crystallization temperature were determined using differential scanning calorimetry ("DSC" ("DSC") in accordance with ASTM D-3417. The differential scanning calorimeter was the DSC Q100 Differential Scanning Calorimeter, which was equipped with cooling liquid nitrogen accessories and UNIVERSAL ANALYSIS 2000 (version 4.6.6) analytical software, both of which are available from T.A. Instruments Inc. of New Castle, Deaware. To prevent direct contact with the samples, tweezers or other tools were used. Samples were placed in an aluminum cup and weighed with an accuracy of 0.01 milligrams on an analytical balance. The lid was screwed over the samples onto a cup. Typically, resin granules were placed in a weighed cup and the fibers were trimmed to fit the position in the weighed cup and when closed with a lid.

The differential scanning calorimeter was calibrated using an indium metal standard and the reference line was adjusted as described in the differential scanning calorimeter user manual. Samples of the material were placed in the working part of the differential scanning calorimeter for testing, and an empty cup was used for comparison. All test tests were carried out using 55 cubic centimeters per minute of nitrogen (industrial grade), which cleans the working part. For samples of resin granules, the heating and cooling program was a 2-cycle test, which began with balancing the working part to -25 ° C, followed by a first heating period with a heating rate of 10 ° C per minute to a temperature of 200 ° C, followed by balancing the samples at 200 ° C for 3 minutes, followed by a first cooling period with a cooling rate of 10 ° C per minute to a temperature of -25 ° C, followed by equilibration of the samples at -25 ° C for 3 minutes, and then a second heating period with a heating rate of 10 ° C per minute to a temperature of 200 ° C. All test tests were carried out using 55 cubic centimeters per minute of nitrogen (industrial grade), which cleans the working part. The results were then evaluated using UNIVERSAL ANALYSIS 2000 analytical software, which determined and quantified the melting and crystallization temperatures.

JOINT FORMING EXAMPLES

Various samples of co-formed webs were formed from two heated streams of meltblown fibers and a single stream of fluffed pulp fibers, as described above and shown in FIG. 1. In various examples, meltblown fibers were formed from the following polymer compositions:

1. Example 1, where the polymer composition was a propylene homopolymer having a density of 0.91 g / cm ³ , a melt flow rate of 1200 g / 10 minutes (230 ° C, 2.16 kg), a crystallization temperature of 113 ° C, and a melting point of 156 ° C, which is commercially available as Metocene ™ MF650X polymer from LyondellBasell Industries, Rotterdam, The Netherlands.

2. Example 2, where the polymer composition was a mixture of 75 wt.% Propylene homopolymer (ACHIVE 693 6G1) and 25 wt.% Propylene and ethylene copolymer (VISTAMAXX 2370, density 0.868 g / cm ³ , melt flow rate 200 g / 10 minutes (230 ° C., 2.16 kg)) having a density of 0.89 g / cm ³ and a melt flow rate of 540 g / 10 minutes (230 ° C., 2.16 kg), which are commercially available from ExxonMobil Chemical Corp., Houston, Texas.

3. Example 2, where the polymer composition was an olefin-based elastomer (VISTAMAXX 2330, density 0.868 g / cm ³ , melt flow rate 290 g / 10 minutes (230 ° C, 2.16 kg), ethylene content 13.0 wt.%), which are commercially available from ExxonMobil Chemical Corp., Houston, Texas.

The polymer compositions each further contain 3.0 wt.% Surfactant (IRGASURF HL, commercially available from Ciba / BASF, Charlotte, North Carolina). The pulp fibers were fully processed pulp of southern softwood obtained from Weyerhaeuser Co. of Federal Way, Washington under the designation "CF-405".

For each Example, the polymer for each meltblown fiber stream was delivered to the corresponding meltblown die at a rate of 2.0 pounds of polymer per inch die head per hour through 0.020 inch diameter openings to achieve a meltblown fiber content of 50% by weight. . The distance from the contact zone to the forming wire (i.e., the forming height) was about 12 inches and the distance between the heads of the meltblown dies was about 6 inches. The melt-blowing head located upstream of the pulp fiber stream was oriented at an angle of 48 ° relative to the pulp stream, while the other melt-blowing head (located downstream from the pulp fiber stream) was oriented at an angle of 48 ° relative to the flow of pulp. The forming wire was FORMTECH ™ 8 (Albany International Co., Albany, New York). To provide various types of pile, rubber sheets were located on the upper surface of the forming wire. One such sheet has a thickness of approximately 0.95 centimeters and contains holes located in a hexagonal matrix. The holes had a diameter of about 0.64 centimeters and were spaced about 0.95 centimeters (the distance between the centers). Sheets with other patterns (e.g. clouds) were also used. The vacuum chamber was located below the forming wire to facilitate application of the web and was filled with up to 30 inches of water.

To demonstrate the elastic properties of the jointly formed webs, the samples of each Example were subjected to a “crumple” test. Each sample was three by seven inches. The test was carried out on both dry and wet samples. Wet samples had 3 of their weight in water added to the sample. Each sample was compressed using light compression into a lump in the user's hand when the sample was held for 10 seconds. Then the samples were released, lightly shaken and laid on the board. Samples were not subsequently smoothed in any direction. FIG. 4 shows a photograph of the samples of Example 1 before collapse. FIG. 5 shows a photograph of the samples of Example 1 after performing a crushing test. FIG. 6 shows a photograph of the samples of Example 3 before collapse. FIG. 7 shows a photograph of the samples of Example 3 after performing a crushing test. As can be seen in FIG. 4-7, the samples of Example 3 were much more elastic, that is, they turned more flat after the crushing test than Example 1. It was similarly found that the samples of Example 2 behave similarly to the samples of Example 3.

In another embodiment of the present invention, one of the layers of the absorbent composite 84 may include air-laid material. The air-laid material, if it is in the retaining layer 94, may also include super absorbent material, such as those described above for the co-molding layer, including super absorbent polymer particles or super absorbent polymer fibers. Air-laid material in any layer may also include fluff pulp fibers, such as those described above for the co-molding layer. Commercially available co-molding materials include materials from Concept Gatineau, Gatineau, Quebec, Canada. Air-laid materials are combinations of fluff pulp fibers and binder fibers that are heated to fuse the binder fibers with fluff pulp fibers, resulting in a stabilized structure.

Air-laid material may be made from a mixture of a first group of fibers, a binder, preferably in the form of a second group of fibers, and may further include a super absorbent material. This combination is cured to form a stabilized, airborne absorbent structure. Air-laid material in this embodiment may have a predetermined base weight between about 50 g / m ² to about 600 g / m ² . Preferably, the air-laid material has a base weight between about 100 g / m ² to about 400 g / m ² . Most preferably, the air laid material has a base weight of about 200 g / m ² . The first group of fibers may be cellulosic fibers, such as fluff pulp fibers, which are short in length, have high density and are hydrophilic. The first group of fibers can be formed from 100% softwood fibers. Preferably, the first group of fibers is Kraft pulp fibers of southern pine species having a length of about 2.5 mm and a density (denier) of more than 2.0. The density of cellulose fibers can be determined by performing a roughness test on a Kajanni test device to obtain a roughness value in units of milligrams per 100 meters (mg / 100 m). This roughness value is then divided by a constant value of 1.1 to obtain the total textile density (denier) in units of grams per 9000 meters (g / 9000 m). Suitable materials for use in the first fiber group include Weyerhaeuser NB 416 and CF 405 pulp fibers, partially processed fluff pulp fibers, which are commercially available from Weyerhaeuser Company of Federal Way, Washington, and Golden Isles 4881 and 4825 fluffy pulp fibers, which are commercially available from Georgia Pacific, Atlanta, Georgia., although any suitable fluff pulp fibers may be used.

The binder portion of the retaining layer may be a chemical coating. Preferably, the binder portion of the retaining layer will include a second group of fibers. The second group of fibers may be synthetic binder fibers. Synthetic binder fibers are commercially available from several suppliers, including Fiber-visions Incorporated, Athens, Georgia and Fiber-visions a / s, Varde, Denmark. Other binder suppliers are Huvis Corporation, South Korea and Far Eastern Textile Company Ltd., Taiwan. Preferably, the second group of fibers is bicomponent fibers having a polyester core surrounded by a polyethylene sheath. Alternatively, the second group of fibers may be bicomponent fibers having a polypropylene core surrounded by a polyethylene sheath. In alternative embodiments, air-laid material that is made of various types of these synthetic binder fibers can be used.

The fibers constituting the second group of fibers are usually longer in length and have a lower density than the fibers constituting the first group of fibers. The length of the fibers of the second group of fibers can be in the range from about 3 mm to about 6 mm. A fiber length of 3 mm works very well. The fibers of the second group of fibers may have a density (denier) of less than or equal to 2.0. The second group of fibers must be intensely moistened and can either be twisted or not twisted. Twisted fibers are preferred because they are better processed.

Air-laid material may also contain superabsorbent material. Super absorbent material is a material that is capable of absorbing at least 10 grams of water per gram of super absorbent material. The super absorbent material is preferably in the form of fine particles, although fibers, flakes or other forms of super absorbent material can also be used. Suitable superabsorbent material is FAVOR SXM 9500, available from EVONIK Stockhausen, Inc, Greensboro, North Carolina. Other similar types of superabsorbent materials, some of which are commercially available from BASF of Charlotte, North Carolina, such as HYSORB 8760 absorbent superabsorbent material, may also be used. Preferably, the superabsorbent material is present in a weight percentage between about 5% to about 60%.

The individual components of the air-laid material may be present in varying amounts. In addition, the components can be distributed homogeneously or heterogeneously over the air laid material. It has been found, however, that the following percentages work well in forming a thin absorbent article. The first group of fibers can be in the range of from about 30% to about 85% by weight of the air laid material. The second group of fibers can be in the range of from about 5% by weight to about 20% by weight of the air laid material. Super absorbent material may be in the range between about 5% by weight to about 60% by weight of the air laid material. It has been found that the formation of air-laid material with about 77% of the first fiber group, about 8% of the second fiber group, and about 15% of the super absorbent material works well to absorb and retain urine or menstrual flow.

The first group of fibers may be present in the air-laid material in a higher weight percentage than the second group of fibers. By using a larger percentage of the first group of fibers, the total cost of the air-laid material can be reduced. The first group of fibers also ensures that the absorbent article has sufficient liquid absorption properties. Cellulose fibers, such as fluff pulp fibers, are generally less expensive than synthetic binder fibers. To ensure good functionality, the second group of fibers may comprise at least about 5 weight% of the air laid material to ensure that the air laid material has sufficient tensile strength. As stated above, the air-laid material should be a mixture of components.

In one embodiment of the present invention, the air-laid material is compressed in a substantially dry state after thermosetting at a temperature of about 165 degrees Celsius for a time between about 8 seconds to about 10 seconds to a density in the range of about 0.05 grams per cubic centimeter g / cm ³ to about 0.3 g / cm ³ . Preferably, the air-laid material is compressed in a substantially dry state to a density in the range of from about 0.07 g / cm ³ to about 0.22 g / cm ³ . Most preferably, the air laid is compressed in a substantially dry state to a density of from about 0.12 (g / cm ³ ). This compression of the air-laid material will contribute to the formation of a thin absorbent article.

Air-laid material, when used in a receiving layer, usually does not include superabsorbent material and has a density in the range of 0.05 g / cm ³ to 0.15 g / cm ³ . The air-laid material used in the retaining layer typically includes a super absorbent material and has a density in the range of 0.1 g / cm ³ to 0.3 g / cm ³ .

It should be noted that the stabilized material constituting the material laid by the air must have sufficient tensile strength in the machine direction to allow it to be wound into rolls, which can later be unwound and processed on the conversion equipment. Adequate tensile strength can be achieved by changing the content of the binder fiber to control the curing conditions, changing the specific density to which the fibers are compacted, and also by other methods known to those skilled in the art. It has been found that air-laid material should have a tensile strength of at least 12 Newtons per 50 mm (N / 50 mm). Preferably, the air-laid material should have a tensile strength of at least 18 N / 50 mm. More preferably, the air-laid material should have the required tensile strength of at least 25 N / 50 mm. The tensile strength of the material can be tested using a test device such as Model MTS / Sintech 1 / S tester, sold by MTS Systems Corporation of Research Triangle Park, North Carolina. Peak tensile strength for the purposes of the present invention is measured by attaching a 50 mm strip of stabilized material between two movable clamping cams of a tensile testing apparatus. A distance of about 10 cm initially separates the two cams. The two cams are then moved outward from each other at a speed of 25 cm / minute until a strip of material breaks. The tensile strength is recorded as the peak load.

In yet another aspect of the present invention, the retaining layer 94 may include fluffy material / super absorbent polymer materials of uniform density with uniform bonds, such as material available as an absorbent core NOVATHIN absorbent core from EAM Corporation, Jesup, Georgia. These materials include a mixture of loose pulp and superabsorbent material that is formed between two layers of tissue or other nonwoven fabric and is dense to form a high density composite between tissue wraps. Particularly suitable superabsorbent polymers are HYSORB 8760 (BASF of Charlotte, North Carolina) and FAVOR SXM 9500 (available from EVONIK Stockhausen, Greensboro, North Carolina). The composition, in General, does not include chemical binders. The composition may further include synthetic binder fibers.

Base weights can range from 80 to 800 g / m ² . The density may be in the range from 0.1 to 0.45 g / cm ³ . The particle content may be in the range from 0-70%. The composition may be embossed with various patterns, including smooth, round or related patterns, as part of the compaction process.

The hydrogen bonding process eliminates the use of synthetic fibers and / or latex in combination with heating in an oven to stabilize the web. Instead, they rely on a combination of temperature and pressure in the calendaring step to induce hydrogen bonding and thus stabilize the web. The main advantage of this technology is the simplification of the production process due to the exclusion of operations on expensive nodes. Other advantages include improved particle retention, such as superabsorbent material and higher absorption efficiency due to the absence of materials that affect the absorption capacity, such as synthetic fibers and binders.

In yet another embodiment of the present invention, one or more layers may include hydraulically bound material. Hydraulically entangled materials include the use of meltblown fibers as part of a structure (e.g., a laminated laminate). The material is hydraulically entangled, which facilitates the interweaving of various fibers and / or filaments. This results in a higher degree of entanglement and allows the use of a wider variety of other fibrous materials in a laminated laminate. In addition, the use of meltblown fibers can reduce the amount of energy required to hydraulically entangle a laminated laminate. In the technology of joining with hydraulic weaving or hydraulic entangling, usually a sufficient number of fibers with unbound (loose) ends (for example, staple fibers and wood fibers) of small diameter and high mobility of fibers are included in the fibrous webs for wrapping and weaving around filaments of fibers of foamed materials, mesh materials and other places of intersection. Without such fibers, the compound of the material may be weak. Continuous fibers of large diameter, which have no disconnected ends and are less mobile, were usually considered as weak fibers for weaving. It has been found, however, that meltblown fibers are more effective for wrapping and weaving or weaving. This is due to the fact that the fibers have smaller diameters and a high surface area, and, indeed, when a sufficiently high flow of energy comes from the jets, the fibers are destroyed, become mobile and intertwined with other fibers. This effect occurs regardless of whether the meltblown fibers are in the layer form described above or in the form of additives.

The use of meltblown fibers (e.g. microfibers) provides an improved product in which weaving among meltblown fibers and other, for example, fibrous materials in a laminated laminate is improved. Thus, due to the relatively long length and relatively small thickness of the meltblown fibers, the interlacing of the meltblown fibers around another material in the laminate is improved. In addition, meltblown fibers have a relatively high surface area, small diameters, and are spaced apart enough to allow other fibrous material in the laminated laminate to move and wrap around and within the meltblown fibers. In addition, since meltblown fibers are numerous and have a relatively high surface area, small diameter, and are nearly continuous, such fibers are excellent for connecting them to free (unbound) fibers (e.g., wood fibers and staple fibers). Attaching or laminating such fibers with meltblown fibers requires relatively low amounts of energy to entangle.

The use of hydraulic entangling technologies for mechanical entangling (for example, mechanical bonding) of a fibrous material, rather than using only other bonding technologies including other hydraulic entangling technologies, provides a composite non-woven fibrous web of material having increased strength, integrity and handling and draping properties, and allows to ensure improved management of other product properties such as absorbency, moisture resistance rated state, etc.

One example of a hydraulically bound material is OPTIMAL GSM 30-250 100% Rayon fabric, available from Baiksan Lintex Co., Ltd, Siheung-City, South Korea.

Hydraulically entangled material generally refers to a material that has been hydraulically entangled. Although hydraulically entangled material is relatively inexpensive, breathable and can be deformed, deformation is generally regarded as permanent, and can be described as unrestorable tension. Nonwoven webs with very small diameter fibers or microfibres have long been known as permeable to air and water vapor, while remaining relatively impermeable to liquids and / or particles. Suitable webs of fibers of small diameter can be made by extruding non-elastomeric thermoplastic polymers using fiber formation processes, such as, for example, melt blowing processes. Although nonwoven webs from meltblown fibers formed from non-elastomeric polymers are relatively inexpensive and breathable, these highly entangled webs do not tend to respond well to tensile forces. The elongation that occurs in such materials is generally regarded as permanent, non-renewable elongation (i.e., non-renewable elongation). For example, nonwoven webs made of conventional thermoplastic polypropylene are generally considered to have non-permanent stretch.

In yet another aspect of the present invention, one or more layers of absorbent composite 84 may include foam, such as material obtained from The Dow Chemical Company, Midland, Michigan. Exemplary absorbent foam materials are described in US Pat. No. 6,627,670, Mork et al., US 6071580, Bland et al., US 7439276, Strandburg et al., And PCT Publications WO 2008/036942 A2, Vansumeren et al., WO 2007/011728 A2, Kirn et al., WO 2008/052122 A1, Menning and WO 2008/100842 A1, Stockton and others, which are incorporated herein by reference to the extent that they do not contradict what is indicated here.

Such absorbent polymeric foamed materials have a hydrophilic, flexible polymeric foamed texture of interconnected open cells. A feature that may be useful in the formation of preferred polymeric foam materials is a cellular structure. Cells of foamed material, and especially cells that are formed by polymerization of a monomer-containing oil phase that surrounds water-phase droplets relatively monomer-free, will often be substantially spherical in shape. These spherical cells are connected to each other by means of openings, which are referred to here as openings between the cells. Both the size or “diameter” of such spherical cells and the diameter of the openings between the cells are generally used to characterize foamed materials. Since the cells and the openings between the cells in a given sample of polymeric foam material will not necessarily have the same dimensions, the average sizes of the cells and openings (that is, the average diameters of the cells and openings) will often be refined.

The dimensions of the cells and holes are parameters that can affect many important and functional features of the foam materials, including the properties of capillary flowing of the liquid, as well as the capillary pressure that forms inside the foam structure. Many technologies are available to determine the average size of the cells and holes of the foam materials. the technology includes a simple measurement based on scanning electron micrographs of a sample of foam material. Foamed materials suitable as absorbent materials for aqueous liquids will preferably have an average mesh size of from about 20 to about 200 microns, more preferably from about 30 to about 190 microns, and most preferably from about 80 to about 180 microns; and an average hole size of from about 5 to about 45 microns and more preferably from about 8 to about 40 microns and most preferably from about 20 to about 35 microns.

For example, US Pat. No. 6,071,580 to Bland et al. Discloses an open-cell absorbent, extruded, thermoplastic foamed material. Foamed material has an open cell content of about 50 percent or more, and an average cell size of up to about 1.5 millimeters. Foamed material can absorb liquid, about 50 percent or more of its theoretical volumetric capacity when absorbing liquid. The foamed material preferably has a structure essentially of cell walls and cell spacers. Also described is a method of absorbing liquid using foam material by lengthening the extrudate of the extrusion head, and a method of improving the absorbency of foam material with open cells by applying a surfactant to the open surface of the foam material, so that the surfactant remains on the surface and does not penetrate substantial distance into the foam.

Suitable foams may also include various types of foams, including, but not limited to, thermoplastic foams, high dispersed emulsion phase (HIPE) foams, inverse high dispersed emulsion phase (I-HIPE) foams, and other suitable polymeric materials foamed materials, including, but not limited to, the materials described in US patent 7053131, Co. and others, US 7358282, Krueger and others, and US 5692939, DesMarais and others, and in patent application US 2006/0148917, Radwanski and others that are included here n lnostyu by reference, to the extent that does not contradict the stated here. Another example of a suitable foam material is a polyurethane foam material with a negative Poisson's ratio. Can also be suitable materials commonly used as lower sheet materials in traditional feminine panty liners. Examples of stretchable lower sheet materials are described in US Pat. No. 5,611,790, Osbom, III, et al., Which is hereby incorporated by reference in its entirety, to the extent that it does not contradict what is indicated here.

Further examples of suitable absorbent foam materials are described in US Patent Application Publication 2006/0246272, Zhang et al., Which is incorporated herein in its entirety by reference, to the extent that it does not contradict what is indicated here.

In another embodiment of the present invention, the retaining layer 94 may include a super absorbent polymer / adhesive composite material including a stretchable super absorbent polymer / adhesive composite material. Such composite materials are described in US patents 5411497, Tanzer and others, US 5433715, Tanzer and others, and US 7247215, Schewe and others, and in the publication of patent application US 2005/0096623 A1, Nhan and others, which are included here completely by reference, to the extent that they do not contradict what is indicated here.

In yet another embodiment of the present invention, one or more layers of the absorbent composite 84 may include a carded bonded web (BCW), such as the web described in US Pat. Nos. 5,364,382, Latimer et al., US 5,429,629, Latimer et al., And US 5,486,166. , Bishop et al., Which are incorporated herein in their entirety by reference, to the extent that they do not contradict what is indicated here. Typical base weights for BCW materials include weights in the range of 30-300 g / m ² . These patents describe BCW wave technology and how BCW wave materials are produced.

In another embodiment of the present invention, one or more layers of the absorbent composite 84 may include meltblown microfibers. An example of such a meltblown microfibre material is Meltblown Strip 50 g / m ² with hydrophilic meltblown material available from Yuhan-K-imberly Kimcheon Nonwoven Mill, KimCheon City, KyungSangBuk-Do, Korea. This material may have a diameter of 1-5 microns polypropylene fiber, a composite density of 0.124-0.218 g / cm ³ , a pore size of 15-18 microns (maximum 21-30 microns) and may further include a wettable surfactant such as a surfactant AEROSOL GPG, available from Cytec Industries Inc., West Paterson, New Jersey.

The development of highly absorbent products for blood and blood-based fluids such as menstrual pads (e.g. sanitary towels), tampons, dressings, bandages, surgical wipes can be difficult. Compared to water and urine, blood and blood-based fluids, such as menstrual flow, are relatively complex mixtures of dissolved and undissolved components (for example, red blood cells or red blood cells). More specifically, blood-based fluids, such as menstrual flow, are much more viscous than urine or water. This higher viscosity interferes with the ability of traditional absorbent materials to efficiently and quickly transport these blood-based fluids to areas remote from the source of emission. The undissolved elements in these blood-based fluids can also potentially clog the capillaries of these absorbent materials. This makes it difficult to design suitable absorbent systems for blood-based fluids such as menstrual flow.

In the case of menstrual pads, women expect a high level of functionality, in terms of comfort and fit, fluid retention and minimal contamination. First of all, fluid leakage from the panty liner is considered unacceptable. Improving the functionality of such menstrual pads continues to be a serious problem, although many improvements have been made both in menstrual structures and in the materials used in these structures. However, the exclusion of leakage, especially along the inner side of the hips, without adversely affecting comfort and fit, does not always meet the desired needs of the consumer.

The absorbent structures of currently available menstrual pads (e.g. sanitary napkins) typically contained one or more fibrous layers to receive the released menstrual fluid from the permeable top sheet and distribute it to the underlying storage area. Absorbent structures for relatively thin varieties of menstrual products of the prior art typically comprise a receiving liquid or a receiving layer that is adjacent to the permeable topsheet. This receiving layer is usually made of air-laid tissue or synthetic non-woven material.

Below this receiving layer is the main absorbent core, which is usually made of air-laid or wet-laid tissue material.

Prior art menstrual absorbent structures made of fibrous layers have many problems. One of them is the difficulty in ensuring adequate dryness of the top sheet. Such structures also had a great chance of causing contamination of the laundry or body. This is due to the fact that the absorbent structure loses elasticity, leading to collapse of the gasket. This loss of elasticity and subsequent crushing also led to the fact that these menstrual pads of the prior art provided a weaker fit and convenience for the user. The conclusion that traditional menstrual absorbent structures and traditional absorbent fibrous webs did not solve this problem was made in US patent 5849805, Dyer.

One of the decisions taken to replace the fibrous absorbent and retaining layers with foam, such as INFINICEL foam, was used in ALWAYS INFINITY Regular gaskets available from The Procter and Gamble, Cincinnati, Ohio. Such foam materials are more expensive than fibrous webs.

Co-molding non-woven webs, which are composites of a matrix of meltblown fibers and an absorbent material (e.g., fluffy wood pulp), have been used as an absorbent layer in a wide variety of applications, including absorbent products, absorbent dry wipes, wet wipes, and mops. Most conventional co-forming webs use meltblown fibers formed from polypropylene homopolymers. One problem that sometimes arises with such co-molding materials, however, is that co-molding materials may not be sufficiently resilient when subjected to bending forces. For example, when the co-molded napkin is wrinkled, the co-molded material may not return to its original flat, crumpled state, as shown in FIG. 4 and 5. As another example, co-molding material used as an absorbent core in an absorbent personal care product may tend to curl.

Thus, the non-woven fabric co-molding described herein can be used in various applications, and shows increased resistance to bending forces and demonstrates the desire to return to a flat state after it has been folded. Such an improved co-molding non-woven fabric can be combined with various other materials for the manufacture of next-generation absorbent composites for use in absorbent personal care products, as shown in FIG. 6 and 7.

The inventors have made research and development efforts to improve absorbent products, and have developed absorbent composites for use in an absorbent core that have adequate wet and dry elasticity and adequate absorbency, without prior use of expensive foam materials. The inventors of the present invention have also found that they can change these properties by combining the elastic material of co-molding with other materials to obtain improved elasticity and absorbent properties.

The products, including the materials described here, showed unexpected and surprising results when tested by consumers compared to a commercial product in which the fibrous web is replaced with foam. Menstrual pads including co-resilient material 215 g / m ² 50% VISTAMAXX polymer / 50% fluff pulp mixture of the receiving layer 86 paired with a retaining layer 94 including EAM 150 g / m ² NOVATHIN high density fluff / polymeric material with hydrogen bonds, including 25% superabsorbent material, were compared with commercially available ALWAYS INFINITY Regular pads, including INFINICEL HIPE foam. Despite these two different technological approaches and costs, both products showed equivalent full compliance with purpose, as well as the same percentage of comfort and absorbency. These results were unexpected since it was assumed that the more expensive INFINICEL foam material would have advantages over the cheaper tested combination of resilient co-molding material / NOVATHIN. Other commercially available products that did not include an elastic co-molding layer or INFINICEL foam were tested in the same way but did not show the same convenience as the two products described in this paragraph.

As described above, prior art menstrual absorbent structures using fibrous webs have a great potential to cause contamination of the laundry and body, as the absorbent structure loses its elasticity, resulting in crushing of the pad. This lack of elasticity and subsequent crushing also led to the fact that the menstrual pads of the prior art provided a weaker fit and convenience for the user. In contrast, the absorbent structure described here solves these problems, as shown in Table 1.

Table 1: Consumer Testing Results Host layer: 108 g / m ² 2330 VISTAMAXX polymer, 108 g / m ² CF 405 pulp fiber ALWAYS INFINITY HIPE Foam pads Traditional padding: ALWAYS Ultrathin Regular Retention layer: EAM NOVATHIN J1501825DTNB material with 25% super absorbent material INFINICEL Foam General convenience 4.3 4.2 3.8 Total Absorbency 4.2 4.2 4.0

These values represent a rating on a five-point scale, with a better value of 5 points. The results in the first two columns have no statistically significant differences.

The results in the third column show a statistically significant difference between the first two columns and show the worst results.

The absorbent composite 84 of the present invention may be better understood with reference to the following test methods and examples of the absorbent composite.

Absorbent Composite Test Method: Side Compression Test

The lateral compression test is used to measure the flexibility and elasticity of a sample of a female panty liner by compression and then decompression of the panty liner sample on the sides. For this test, a constant tensile strength tensile testing (CRE) device was used (such as the MTS SINTECH 500 / S model. Serial No. 500S / 062696/203 or its equivalent). The data collection software is MTS TESTWORKS for Windows Ver. 4.11 C (MTS Systems Corporation, Eden Prairie, MN). The load cell is selected from either 50 Newtons or 100 Newtons, maximum, depending on the magnitude of the peak load, so that most of the peak load falls between 10-90% of the full scale of the load cell. In this test, both edges of the gasket (i.e., the linear and outer covering laminated laminate) are compressed between the upper and lower clamps of the tensile testing apparatus, with the center of the sample aligned with the center of the clamps, and the sample is centered between the clamps. The width of the surface of the clamps is 3 inches (76.2 mm) and the approximate height of the clamps is 1.0 inch (25.4 mm). The test speed is 5 +/- 004 in / min (127 +/- 1 mm / min) both in compression mode and in decompression mode. The original design length is set to 55 mm. When the test begins, the clamps move towards each other to compress the sample until the distance between the clamps is 20 +/- 1 mm. The clamps are then returned to their original positions upon completion of the test. The sample can be tested in a dry state. In addition, the test dry sample can be wetted with 5 ml of liquid and re-tested for wet conditions.

Make a graph of pressure versus distance to build a compression curve. The pressure plot versus distance is also plotted when the sample is released from compression by constructing a decompression curve.

These test parameters of interest are as follows. Peak compression force (gf) is the maximum force defined in the compression curve to the compression distance. A higher value indicates that more force is needed to compress the product to a specific thickness. In a specific application, the consumer carries the product, squeezing it between the legs. A higher peak compressive force suggests that more force is needed to compress the product. Compression energy (gf cm) is the area under the compression curve. A higher value indicates that the product is harder to compress. In a particular application, this means that more energy is required to compress the product between the legs. This parameter covers all points, not just peak force. Finally, the compression elasticity (%) is the ratio of the decompression region to the compression region. A higher value indicates a greater recovery. In specific applications, the wearer wears the product, squeezing it between her legs. When she relaxes them, the product returns to its original state. This is preferable to reduce wrinkling and twisting. From a convenience point of view, ideally, the user wants the product to compress easily (low peak force, low energy) and be resilient.

The same test method is used to obtain data on wet compression and elasticity in Table 2, except that 5 ml of menstrual fluid simulating fluid is added to the dry pad by spraying the fluid with a syringe over the entire area of the body lining. The used substance that simulates menstrual flow is made of pig blood diluted to a hematocrit level of 30% of the volume with crushed thick egg white added to simulate the mucin component of the menstrual flow. This mimicking agent is available from Cocalico Biologicals, me, Reamstown, PA and is described in US Pat. No. 5,883,231, Achter et al., And US Pat. No. 7,632,258, Misek et al., Which are hereby incorporated in their entirety by reference to the extent that they do not contradict here.

Absorbent Composition Examples

Example A: Commercially available ALWAYS INFINITY Regular Flow Pad.

Example B: U from COTECH CLEANWEAR Regular pad.

For the following examples, VISTAMAXX 2330 polymer is available from ExxonMobil Chemical Corp., CF 405 pulp fibers are available from Weyerhaeused Co., and FAVOR SXM9500 super absorbent is available from Evonik Stockhausen, Inc.

Example 1: A gasket with the shape shown in FIG. 11, has been manufactured and tested; gasket comprises a first acquisition layer (86) comprising elastic material co-molding 108 g / m ² VISTAMAXX 2330 polymer to 108 g / m ² CF 405 pulp fibers, and the storage layer (94) comprising material ASB NOVATHIN J1501825DTNB (fluff material / the superabsorbent high density polymer material with hydrogen bonds).

Example 2: A gasket with the shape shown in FIG. 10, but without holes (95) was produced and tested; the gasket included a first receiving layer (86) comprising a co-molded elastic material having 108 g / m ² VISTAMAXX 2330 polymer with 108 g / m ² CF 405 pulp fiber and a retaining layer (94) including BAM NOVATHIN J1501825DTNB (fluffy material / super absorbent polymer material of high density with hydrogen bonds).

Example 3: Gasket with the mold shown in FIG. 10, but without holes (95) was produced and tested; the gasket included a first receiving layer (86) comprising a co-molded elastic material having 108 g / m ² VISTAMAXX 2330 polymer with 108 g / m ² CF 405 pulp fiber and a retaining layer (94) including BAM NOVATHIN J1501825DTNB (fluffy material / super absorbent polymer material of high density with hydrogen bonds), and a distribution layer (96), including 2 layers of 50 g / m ² meltblown microfibers.

Example 4: A gasket with the shape shown in FIG. 10, but without holes (95) was produced and tested; the gasket included a layer comprising co-molded elastic material having 108 g / m ² VISTAMAXX 2330 polymer with 108 g / m ² CF 405 pulp fiber and a second layer comprising Glatfelter Airlaid DT200.102 air-laid material.

Example 5: A gasket with the shape shown in FIG. 10, has been produced and tested; the gasket included the first receiving layer (86), including 150 g / m ^{2 of} polyolefin foam, with a density of 0.07 g / cm ³ and 0.5 ounces / yard ² spunbond production substrate, and a retaining layer (94) including 215 g / m ² co-molding material made from 108 g / m ² VISTAMAXX 2330 polymer, 75 g / m ² CF 405 pulp fibers, and 32 g / m ² FAVOR SXM9500 super absorbent particles. A pattern of 41 holes (95), each with a diameter of 3 mm, is located in the pattern shown in FIG. 10, was formed through both layers. The outline of the gasket shown in FIG. 10 is shown for context to show the overall hole ratio (95).

Example 6: Gasket with the shape shown in FIG. 10, but without holes (95) was produced and tested; the gasket included a first receiving layer (86) comprising an elastic co-molding material having 108 g / m ² VISTAMAXX 2330 polymer with 108 g / m ² CF 405 pulp fiber and a retaining layer (94) including 215 g / m co-forming material made from 108 g / m VISTAMAXX 2330 polymer, 75 g / m ² CF 405 pulp fiber, and 32 g / m ² FAVOR SXM9500 super absorbent particles.

Example 7: Gasket with the shape shown in FIG. 10, but without holes (95) was produced and tested; the gasket included a first receiving layer (86) comprising a co-molded elastic material having 108 g / m VISTAMAXX 2330 polymer with 108 g / m ² CF 405 pulp fiber and a retaining layer (94) including 100 g / m ² hydraulically bound material .

Table 2: Test Results: Side Compression Test Peak Compression Force (gf) Compression Energy (gs * cm) Compression Elasticity (%) When measures Receiving layer Holding layer Distribution layer Dry 5 ml of a simulating substance Dry 5 ml of a simulating substance Dry 5 ml of a simulating substance BUT ALWAYS INFINITY Regular Pad (data code 83394786671506) 160 106 262 252 44 44 AT U from COTECH CLEANWEAR Regular pad (data code BJ925405X1337) 321 238 685 532 32 29th one co-molded elastic material 108 g / m ² VM2330, 108 g / m ² CF 405, without holes EAM NOVATHIN J1501825DT NB material no one hundred 102 285 245 66 52 2 co-molded elastic material 108 g / m ² VM2330, 108 g / m ² CF 405, without holes EAM NOVATHIN J1501825DT NB material no 55 49 138 96 47 twenty 3 co-molded elastic material 108 g / m ² VM2330, 108 g / m ² CF 405, without holes EAM NOVATHIN J1501825DT NB material 2 layers of 50 g / m ² meltblown microfibre 103 95 296 264 37 23 four co-molded elastic material 108 g / m ² VM2330, 108 g / m ² CF 405, without holes Glatfelter Airlaid DT200.102 no 114 82 336 242 44 33 5 150 g / m ² polyolefin foam material, density = 0.07 g / cm ³ and 0.5 ounces / yard ² substrate of spunbond production method, with a pattern of holes Co-molding material: 108 g / m2 VM2330, 75 g / m2 CF 405, 32 g / m2 SXM9500, with hole pattern no 104 99 231 200 35 40 6 co-molded elastic material 108 g / m ² VM2330, 108 g / m ¹ CF 405, without holes Co-molding material: 108 g / m2 VM2330, 75 g / m2 CF 405, 32 g / m2 SXM9500 no 65 60 159 149 26 23 7 co-molded elastic material 108 g / m ² VM2330, 108 g / m ² CF 405, without holes 100 g / m2 hydraulically bound material from Baiksan Lintex Co., Ltd no 62 60 140 144 22 13

- VM2330 refers to VISTAMAXX 2330 polymer, available from ExxonMobil Chemical Corp.,

- CF 405 refers to CF 405 pulp fibers available from Weyerhaeused Co.

- SXM9500 is a FAVOR SXM9500 Super Absorbent Material available from Evonik Stockhausen, Inc.

- Since the gasket shape can also affect the measured compressibility and elasticity, the gasket shape of FIG. 11 was used in Example 1, and the gasket shape of FIG. 10 was used in Examples 2-7.

Each of the above examples, including co-elastic resilient material, had peak forces comparable to the peak forces of the ALWAYS INFINITY Regular Pad or lower.

Although the invention has been described in detail regarding specific embodiments, it will be understood that those skilled in the art, upon understanding the foregoing, can readily understand the changes, variations and equivalents of these embodiments. Accordingly, the scope of the present invention should be appreciated within the scope of the appended claims and any equivalents thereof. In addition, it should be understood that any given range presented here is intended to include any smaller ranges included therein. For example, a range from 45-90 will also include 50-90, 45-80, 46-89, and the like.

Claims (22)

1. Absorbent composite located in an absorbent product between the upper sheet and the lower sheet, and the absorbent composite contains:
a first receiving layer located between the top sheet and the bottom sheet, and
a retaining layer located between the upper sheet and the lower sheet, and one of the first receiving layer and the retaining layer includes an elastic material of joint molding,
wherein the co-molding elastic material comprises a matrix of meltblown fibers and an absorbent material, wherein the meltblown fibers comprise from 30 wt.% to about 99 wt.% of the web, and the absorbent material is from about 1 wt.% to about 70 wt. .% of the fabric, and the meltblown fibers are formed from a thermoplastic composition that contains at least one copolymer of polypropylene and α-olefin having a propylene content of from about 60 mol.% to about 99.5 mol.%, and the content of α-olefin from about 0.5 mol.% to colo 40 mol.%, wherein the copolymer further has a density of from about 0.86 to about 0.90 g / cm ^3, and the composition has a melt flow rate of from about 120 to about 6000 grams per 10 minutes, determined at 230 ° C in in accordance with the test method of ASTM D1238-E. 2. The absorbent composite according to claim 1, in which the first receiving layer includes an elastic joint molding material, and the retaining layer includes one of a joint molding material, an elastic joint forming material, a web of carded material (BCW), and a dry air molding material . 3. The absorbent composite of claim 2, wherein the retaining layer further includes a super absorbent material. 4. The absorbent composite according to claim 2, in which the retaining layer further includes a fluff pulp. 5. The absorbent composite according to claim 1, in which the first receiving layer includes a co-forming elastic material, and the retaining layer includes one of the fluffed material / super absorbent polymer material of high density with hydrogen bonds, hydraulically interwoven material, composite material super absorbent polymer / adhesive and foam. 6. The absorbent composite of claim 5, wherein the retaining layer further includes fluff pulp. 7. The absorbent composite according to claim 1, wherein the retaining layer includes a co-molding elastic material, and wherein the first receiving layer includes one of co-molding material, co-forming elastic material, dry air molding material, carded bonded material (BCW), and foam. 8. The absorbent composite of claim 7, wherein the first receiving layer further includes a fluff pulp. 9. The absorbent composite according to claim 7, in which the elastic material co-molding in the holding layer includes a super absorbent material. 10. The absorbent composite according to claim 1, additionally containing a distribution layer located between the upper sheet and the lower sheet, the distribution layer comprising one of the meltblown microfiber material of hydraulically entangled material and foam material. 11. The absorbent composite of claim 1, wherein the first receiving layer includes co-forming elastic material, and wherein the retaining layer includes fluffy material / super absorbent high density polymer material with hydrogen bonds. 12. The absorbent composite according to claim 1, in which the first receiving layer includes an elastic material of joint molding, and the retaining layer includes a material of dry air molding. 13. The absorbent composite according to claim 1, in which both the first receiving layer and the retaining layer include an elastic material co-molding. 14. The absorbent composite of claim 13, wherein the retaining layer further includes a super absorbent material. 15. The absorbent composite according to claim 1, additionally containing a second receiving layer located generally parallel to the first receiving layer, the second receiving layer comprising one of a dry air molding material, a web of carded material (BCW), an elastic joint forming material , and foam. 16. The absorbent composite according to claim, in which the receiving layer is located between the upper sheet and the retaining layer, and the retaining layer is located between the lower sheet and the receiving layer. 17. Absorbent composite located in the absorbent product between the upper sheet and the lower sheet, and the absorbent composite contains:
a first receiving layer including one of a co-molding material, an elastic co-molding material, a dry-air molding material, a carded bonded material (BCW), and a foam material; and
a retaining layer located between the top sheet and the bottom sheet, and the retaining layer includes one of a joint molding material, an elastic joint molding material, a dry air molding material, a fluffed material / a high density super absorbent polymer material with hydrogen bonds, a hydraulically bound composite material of a super absorbent polymer material / adhesive and foam, wherein one of the first receiving layer and the retaining layer includes an elastic material co-molding terial,
wherein the co-molding elastic material comprises a matrix of meltblown fibers and an absorbent material, wherein the meltblown fibers comprise from 30 wt.% to about 99 wt.% of the web, and the absorbent material is from about 1 wt.% to about 70 wt. .% of the web, and the meltblown fibers are formed from a thermoplastic composition that contains at least one copolymer of polypropylene and α-olefin having a propylene content of from about 60 mol% to about 99.5 mol%, and an α-olefin content of from about 0.5 mol % to about 40 mol.%, the copolymer additionally having a density of from about 0.86 to about 0.90 g / cm ³ and the composition has a melt flow rate of from about 120 to about 6000 g in 10 minutes, determined at 230 ° C in accordance with the test method of ASTM D1238-E. 18. Absorbent composite adapted for placement in an absorbent product between the upper sheet and the lower sheet, and the absorbent composite contains:
a first receiving layer comprising elastic co-molding material; and
a retaining layer located between the top sheet and the bottom sheet, and the retaining layer includes one of a joint molding material, an elastic joint molding material, a dry air molding material, a fluffy material / super absorbent polymeric material of high density with hydrogen bonds, a hydraulically bound material, a composite material a super absorbent polymer / adhesive and foam,
wherein the co-molding elastic material comprises a matrix of meltblown fibers and an absorbent material, wherein the meltblown fibers comprise from 30 wt.% to about 99 wt.% of the web, and the absorbent material is from about 1 wt.% to about 70 wt. .% of the fabric, and the meltblown fibers are formed from a thermoplastic composition that contains at least one copolymer of polypropylene and α-olefin having a propylene content of from about 60 mol.% to about 99.5 mol.%, and the content of α-olefin from about 0.5 mol.% to colo 40 mol%, wherein the copolymer further has a density of from about 0.86 to about 0.90 g / cm ^3, and the composition has a melt flow rate of from about 120 to about 6000 grams per 10 minutes, determined at 230 ° C under with the test method of ASTM D1238-E. 19. An absorbent feminine hygiene product having a top sheet and a bottom sheet containing:
an absorbent composite located between the upper sheet and the lower sheet, wherein the absorbent composite includes a first receiving layer including elastic co-molding material, and a retaining layer located between the upper sheet and the lower sheet, and the holding layer includes one of the co-molding material, the elastic material of the joint molding, dry air molding material, fluffy material / super absorbent high density polymer material with hydrogen bonds, hydraulic bound material, composite superabsorbent polymer / adhesive and foam,
wherein the co-molding elastic material comprises a matrix of meltblown fibers and an absorbent material, wherein the meltblown fibers comprise from 30 wt.% to about 99 wt.% of the web, and the absorbent material is from about 1 wt.% to about 70 wt. .% of the fabric, and the meltblown fibers are formed from a thermoplastic composition that contains at least one copolymer of polypropylene and α-olefin having a propylene content of from about 60 mol.% to about 99.5 mol.%, and the content of α-olefin from about 0.5 mol.% to colo 40 mol.%, wherein the copolymer further has a density of from about 0.86 to about 0.90 g / cm ^3, and the composition has a melt flow rate of from about 120 to about 6000 grams per 10 minutes, determined at 230 ° C in in accordance with the test method of ASTM D1238-E. 20. A method of performing an absorbent personal care product having an absorbent composite, the method comprising:
combining the flow of absorbent material with the flow of meltblown fibers to form a composite stream;
collecting the composite stream onto the forming surface to form a non-woven elastic co-molding material; and
combining a non-woven elastic material of co-molding with the top sheet and the bottom sheet,
wherein the co-molding elastic material comprises a matrix of meltblown fibers and an absorbent material, wherein the meltblown fibers comprise from 30 wt.% to about 99 wt.% of the web, and the absorbent material is from about 1 wt.% to about 70 wt. .% of the fabric, and the meltblown fibers are formed from a thermoplastic composition that contains at least one copolymer of polypropylene and α-olefin having a propylene content of from about 60 mol.% to about 99.5 mol.%, and the content of α-olefin from about 0.5 mol.% to colo 40 mol.%, wherein the copolymer further has a density of from about 0.86 to about 0.90 g / cm ^3, and the composition has a melt flow rate of from about 120 to about 6000 grams per 10 minutes, determined at 230 ° C in in accordance with the test method of ASTM D1238-E. 21. Absorbent composite, suitable for use in an absorbent product having a top sheet and a bottom sheet, and the absorbent composite contains:
a receiving layer comprising foam material located between the upper sheet and the lower sheet, the receiving layer having a plurality of holes in it; and a retaining layer located between the upper sheet and the lower sheet, and the retaining layer includes an elastic material co-molding,
wherein the co-molding elastic material comprises a matrix of meltblown fibers and an absorbent material, wherein the meltblown fibers comprise from 30 wt.% to about 99 wt.% of the web, and the absorbent material is from about 1 wt.% to about 70 wt. .% of the fabric, and the meltblown fibers are formed from a thermoplastic composition that contains at least one copolymer of polypropylene and α-olefin having a propylene content of from about 60 mol.% to about 99.5 mol.%, and the content of α-olefin from about 0.5 mol.% to colo 40 mol.%, wherein the copolymer further has a density of from about 0.86 to about 0.90 g / cm ^3, and the composition has a melt flow rate of from about 120 to about 6000 grams per 10 minutes, determined at 230 ° C in in accordance with the test method of ASTM D1238-E. 22. The absorbent composite according to claim 21, in which the retaining layer has many holes in it.

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