MXPA99006743A - Water-dispersible fibrous nonwoven coform composites - Google Patents

Abstract

Disclosed herein is a fibrous nonwoven composite structure more commonly referred to as a coform structure. Unlike current coform structures, the material of the present invention is more water-dispersible due to the use of a water-degradable reinforcing fiber matrix.

Description

COMPOUNDS COFORM NON-TISSUE FIBROUS DISPERSIBLE IN WATER FIELD OF THE INVENTION The present invention relates to fibrous nonwoven composite structures dispersible in water comprising at least two different components wherein the compound is dispersible in water. More particularly, the present invention relates to fibrous non-woven composite structures referred to as "coform" materials which are dispersible in water.

BACKGROUND OF THE INVENTION Fibrous nonwoven materials and fibrous nonwoven composites are widely used as products or as components of products because they can be manufactured cheaply and can be made to have specific characteristics. One approach has been to mix the thermoplastic polymer fibers with one or more types of fibrous and / or particulate material. The blends are collected in the form of fibrous nonwoven fabric composites which can be joined or treated to provide coherent nonwoven composites that take advantage of at least some of the properties of each component. For example, U.S. Patent No. 4,100,324 issued July 11, 1978 to Anderson et al., Describes a non-woven fabric. woven which is generally a uniform combination of meltblown thermoplastic polymer and wood pulp fibers. U.S. Patent No. 3,971,373 issued July 7, 1976 to Braun discloses a non-woven material which contains meltblown thermoplastic polymer fibers and discrete solid particles. According to this patent, the particles are uniformly dispersed and intermixed with the meltblown fibers in the non-woven material. U.S. Patent No. 4,429,001 issued January 31, 1984 to Kolpin et al. Describes an absorbent sheet material which is a combination of melt blown thermoplastic polymer fibers and solid superabsorbent particles. The superabsorbent particles are described as being uniformly dispersed and physically retained within a fabric of the melt blown thermoplastic polymer fibers. European Patent No. 0080382 issued to Minto et al. Published on July 1, 1983 and European Patent No. 0156160 issued to Minto et al. Published on October 25, 1985 also discloses combinations of particles such as superabsorbents and fibers. blown thermoplastic polymer with fusion. U.S. Patent No. 5,350,624 issued to Georger et al. And issued September 27, 1994 discloses an abrasion-resistant fibrous non-woven structure composed of a fiber matrix of meltblown material having a first surface outside, a second outer surface and an inner part with at least one other fibrous material integrated within the meltblown fiber matrix. The concentration of the meltblown fibers adjacent to each outer surface of the non-woven structure is at least about 60 weight percent and the concentration of the meltblown fibers in the inner part is less than about 60 weight percent. 40 percent by weight. Many of the aforementioned combinations are referred to as "coform" materials because they are formed by combining two or more materials in the formation step in a single structure.

The coform compounds can be used in a wide variety of applications including absorbent media for organic and aqueous fluids, filter media for wet and dry applications, insulating materials, protective cushioning materials, containment and delivery systems and media of cleaning for both wet and dry applications. Many of the above applications can be made, to varying degrees, through the use of more simplified structures such as absorbent structures where only wood pulp fibers are used. This has commonly been the case with, for example, the absorbent cores of absorbent personal care products such as diapers. Wood pulp fibers when formed by themselves tend to produce structures of nonwoven fabric which have very little mechanical integrity and have a high degree of folding when wet. The advent of coform structures which incorporate thermoplastic meltblown fibers, even in small quantities, greatly improve the properties of such structures including both wet and dry tensile strength. The same increases have also been seen with the advent of the coform cleaning sheets.

Many of the articles or products within which coform materials are incorporated are generally viewed as being disposable products of limited use. By this it is meant that the product or some of the products are used only a limited number of times and in some cases only once before being discarded. With increasing concerns about waste disposal, there is now an increasing push for materials that are, for example, either recyclable or that can be disposed of through other mechanisms besides being incorporated into the landfills. A possible alternative means of disposal for many products, especially in the area for absorbent personal care products and cleaners, is by depositing them in the toilets to the drainage waste systems.

The reason why many coforp-materials provide increased benefits over conventional materials, for example, melt-blown thermoplastic fiber material, is the same reason why such materials are more difficult to recycle or drain. Many products based on wood pulp fiber can be recycled by hydrating them and re-pulping the reclaimed wood pulp fibers. However, in coform structures the thermoplastic meltblown fibers do not break easily. The meltblown fibers with hard to separate from the wood pulp fibers, and these remain essentially continuous giving rise to the possibility of clogging or otherwise damaging the recycling equipment such as the machines to re-mace the pulp . From the point of view of draining, the current belief is that to be drainable, a product must be made of very small and / or very weak fibers so that the material can easily break into small pieces when placed in quantities of water such as those found in the use of toilets, and again due to the nature of the fibers, when drained they will not be trapped or clogged within the pipeline of conventional public and private drainable waste systems. Many of these systems, especially the lateral ones of the drainage can have many protuberances inside the pipes such as roots of trees which can hang and catch any type of material that is still relatively intact.

Such would be the case with thermoplastic meltblown fibers non-degradable in conventional water in coform materials. As a result of this, at least for the above reasons there is a need for a coform material which has the potential to be friendlier with respect to the recycling and discarding processes through the alternate means to the landfill such as, for example, the drained. Therefore, it is an object of the present invention to provide such material.

SYNTHESIS OF THE INVENTION The present invention is directed to a fibrous non-woven composite structure dispersible in water which utilizes at least two different components and wherein the compound is dispersible in water. Such structures are more commonly referred to as "coform" materials. The water-dispersible fibrous non-woven composite structure comprises a matrix of spin-bonded water-degradable reinforcing fibers and a multiplicity of discrete absorbent fibers which are disposed within the matrix of melt-spun degradable water-reinforcing fibers. The absorbent fibers may include, for example, short fibers having average fiber lengths of about 18 millimeters or less as well as wood pulp fibers. In addition, the fibrous nonwoven composite structure dispersible in Water may further include a particulate material within the matrix such as a superabsorbent and / or an odor reducing agent such as, for example, activated carbon. Examples of melt-bonded water-degradable reinforcing fibers include, but are not limited to, water-degradable polyamides and polyvinyl alcohol. Instead of or in addition to the multiplicity of discrete absorbent fibers, the fibrous non-woven composite structure dispersible in water may comprise a plurality of particles placed within and held by the matrix of melt-degradable spun water-reinforcing fibers. The materials of the present invention can be used in a wide variety of applications including, for example, absorbent articles for personal care such as diapers, cleansers, training underpants, panty liners, sanitary napkins, devices of incontinence, wound dressings, bandages and the like.

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a side elevation and schematic, partially in section, of a possible method and an apparatus for producing fibrous nonwoven composite structures dispersible in water according to the present invention.

Figure 2 is a perspective view of a fragment of a fibrous nonwoven composite structure produced by the method and apparatus of Figure 1.

Figure 3 is a partial schematic side elevation of another possible method and an apparatus for producing fibrous nonwoven composite structures dispersible in water according to the present invention.

Figure 4 is a plan view of an upper platen of a film pressure fixture used in the formation of polymer film samples.

Figure 5 is a cross-sectional view of the upper platen of Figure 4.

Figure 6 is a plan view of the bottom platen of the film press accessory used in forming polymer film samples.

Figure 7 is a cross-sectional view of the lower platen of Figure 6.

DETAILED DESCRIPTION OF THE INVENTION The present invention is directed to a fibrous non-woven composite structure, which has at least two different components which are dispersible in water. As used herein, the term "fibrous nonwoven composite structure" refers to a structure of individual fibers or filaments with or without particulates which are interleaved, but not in an identifiable repetitive manner. Non-woven structures such as, for example, fibrous non-woven fabrics have been formed in the past, by a variety of processes known to those skilled in the art including, for example, meltblowing and spinning processes. melted, the processes of union with spinning and the processes of carded and united fabric.

As used herein, the term "water dispersible" refers to a fibrous non-woven composite structure which when placed in an aqueous environment, with sufficient time, will break into smaller pieces. As a result of this, the structure once dispersed can be more advantageously processable in a recycling process or drained in, for example, municipal and septic drainage treatment systems. If desired, such fibrous nonwoven structures can be made more dispersible in water or the dispersion can be increased by the use of agitation and / or certain trigger mechanisms as will be described later. The actual amount of time will depend at least in part on the particular end-use design criteria. For example, in the sanitary towel modalities described below, the fibers break in less than one minute. In other applications, longer times are desirable.

The fibrous nonwoven structure according to the present invention includes a reinforcing fiber joined with spinning made of a water degradable polymer and one or more components which are intermixed with the reinforcing fiber to form a fibrous nonwoven composite structure according to the present invention. By "melted yarn" is meant a fiber which is formed by a fiber-forming process which gives more continuous and longer fibers (generally in excess of 7.5 centimeters) such as those made by the blowing processes with fusion and union with spinning. By "degradable in water" is meant a polymer which when formed in a fiber and placed in sufficient amounts of water for a sufficient period of time will break into smaller pieces. In some cases, the agitation may be necessary to break the fibers and separate them. Here again the actual time may vary or may be varied to meet a particular end-use requirement. Many of the polymers can be designed today or selected to break in the order of minutes or less. The most common form of the structure fibrous nonwoven composite according to the present invention is commonly referred to as a coform material which includes more continuous and longer melt spinning fibers interspersed with shorter absorbent fibers such as short length fibers and fibers or particulates of wood pulp such as superabsorbents. The short length fibers generally have lengths which extend up to about 7.5 centimeters. There are many currently available short fibers which generally have lengths of less than about 18 millimeters and which can be made from a variety of thermoplastic extrudable polymers including, but not limited to polyolefins and polyesters as well as homopolymers, copolymers and mixtures of such polymers. In addition, various different types and / or sizes of such fibers can be used in the coform structure. Another example of the absorbent fibers are the pulp fibers. The pulp fibers are generally obtained from natural sources such as woody and non-woody plants. Woody plants include, for example, coniferous and deciduous trees. Non-woody plants include, for example, cotton, flax, esparto grass, straw, jute and bagasse. In addition, synthetic wood pulp fibers are also available and can be used with the present invention. Wood pulp fibers typically have lengths of about 0.5 to 10 millimeters and a maximum width to length ratio of about 10/1 to 400/1. A typical cross section has an irregular width about 30 micrometers and a thickness of about 5 micrometers. A wood pulp suitable for use with the present invention is the Kimberly-Clark CR-54 wood pulp from Kimberly-Clark Corporation of Neenah, Wisconsin. Another is NF405 from Weyerhauser Corporation, of Federal Way, Washington.

Water-degradable reinforcing fibers will typically have excess lengths of the absorbent fibers including short fibers and wood pulp fibers. Examples of two water-degradable reinforcing fibers are meltblown fibers and spunbonded fibers. The meltblown fibers are formed by extruding a melted thermoplastic material through a plurality of matrix, usually circular and fine, capillary blood vessels, melted threads or filaments into a heated high speed gas stream such as air, the which attenuates the filaments of the melted thermoplastic material to reduce its diameters. Then, the meltblown fibers are carried by the high velocity gas stream and are deposited on a collecting surface to form a meltblown fabric randomly dispersed. Melt blowing processes are well known and are described in several patents and publications, including the Naval Research Laboratory Report 4364"Manufacturing of Superfine Organic Fibers" by B. A. Wendt, E. L. Boone and C. D. Fluharty; Naval Research Laboratory Report 5265, "A Enhanced Device for the Formation of Superfine Thermoplastic Fibers "by KD Lawrence, RT Lukas, JA Young, U.S. Patent Number 3,676,242 issued July 11, 1972 to Prentice, and the U.S. Patent Number 3,849,241, issued November 19, 1974 to Buntin et al. The above references are hereby incorporated by reference in their entirety Such meltblown fibers can be made in a wide range of diameters Typically, such fibers will have an average diameter of no more about 100 micrometers and usually no more than 15 micrometers.

Spunbond fibers are formed by extruding a melted thermoplastic material as filaments of a plurality of capillary, usually circular and fine vessels in a spinning organ with the diameter of the extruded filaments then being rapidly reduced, for example, by bonding mechanisms with well-known spinning of eductive or non-eductive fluid or others. The production of non-woven fabrics bonded with yarn is illustrated in patents such as that of Appel and others of the United States of America Number 4,340,563; of Matsuki et al., United States of America Patent Number 3,802,817; from Dorschner et al., U.S. Patent Number 3,692,618; of Kinney, United States of America Patents Nos. 3,338,992 and 3,341,394; of Levy, United States patent of North America Number 3,276,944; from Peterson, United States of America Patent Number 3,502,538; from Hartman, United States of America Patent Number 3,502,763; from Dobo et al., U.S. Patent Number 3,542,615; and the Canadian patent of Hartman Number 803,714. All the above references are incorporated herein by this mention in its entirety.

In addition to water degradable reinforcing fibers and absorbent fibers such as short fibers and wood pulp fibers, the fibrous nonwoven structure according to the present invention can employ superabsorbent materials. The superabsorbent materials are the absorbent materials capable of absorbing at least 10 grams of aqueous liquid (eg, distilled water) per gram of absorbent material while being submerged in a liquid for four hours and which will retain essentially all of the liquid absorbed while which are under a compression force of up to about 10 kilopascals (Kpa). Super-absorbent materials are produced in a wide variety of ways including, but not limited to particles, fibers and flakes. Such superabsorbent materials can be used in the present invention in combination with water-degradable reinforcing fibers and shorter fibers or instead of short fibers.

Due to the more continuous and longer nature of the fibers formed by the above meltblowing and spunbond processes, such fibers and the resulting non-woven fabrics including the coform fabrics do not break easily due to their inherent toughness of the fibers. blown fibers with melting and / or joined with spinning. As a result of this, coform materials which are predominantly wood pulp fibers which still contain longer fibers such as polyolefin meltblown fibers are difficult to claim in such apparatuses and to re-form pulp. In addition, these more continuous and longer fibers also tend to hang on or over the protuberances on the sides of the strainers making it difficult for composite materials to transfer through the drainage treatment system. The fibrous non-woven composite structures according to the present invention use a water degradable reinforcing fiber which can be made, for example, by the meltblown and spunbond processes described and mentioned above.

Not all polymers, of course, can be processed by melt spinning processes such as meltblowing and spin bonding and the polymers used in the practice of this invention can be melt-spun and water-degradable. Water degradable polymers which have been found to be particularly Suitable for melt spinning include those with viscosities between 20 and 35,000 centipoises at a cutoff rate of 1,000 seconds "1 at normal processing temperatures of about 75 to about 250 ° C, depending on the type of polymer. Water-degradable materials, when formed into fibers and mixed with absorbent materials such as wood pulp and / or short-length fibers and / or particles such as superabsorbents, can form fibrous non-woven structures mentioned as coform materials. have subsequent end uses which involve the exposure of structures to aqueous liquids including, but not limited to, tap water, waste water, and body fluids such as blood and urine. conventional coform fibroses are used as absorbent products either alone, as in the form of cleaning cloths, or as a items of other absorbent devices such as absorbent articles for personal care, including, but not limited to diapers, training pants, incontinence garments, sanitary napkins, plugs, wound dressings, bandages and the like. It is therefore desirable that the fibrous nonwoven composite structures of the present invention be able to withstand the rigors of these intended uses, and then, upon completion of particular uses, the fibrous nonwoven composite structures should be made dispersible in water.

Certain polymers are only degradable in water when exposed to sufficient quantities of an aqueous liquid within a certain pH range. Outside of this range, these will not degrade. Therefore, it is possible to choose a polymer degradable in water sensitive to pH which will not be degraded in a liquid or aqueous liquids in a pH range such as, for example, a pH of 3 to 5, but which will degrade in an excess of water from the tap. See, for example, U.S. Patent No. 5,102,668 issued to Eichel et al. Which is hereby incorporated by reference in its entirety. Therefore, when the fibrous nonwoven compounds are exposed to body fluids such as urine, the water degradable reinforcer fibers will not degrade. After use, such a fibrous non-woven composite structure can be placed in excess amounts of higher pH liguids such as tap water which will cause degradation of the degradable polymer in water by making the reinforcing fibers. As a result of this, the more continuous and longer reinforcing fibers will begin to break either by themselves or with sufficient agitation so that discrete fibrous components, such as wood pulp fibers can be reclaimed, recycled or disposed of. by draining. Examples of the polymers which may be used to form this type of fiber may include the copolymers of methacrylic or acrylic acid / acrylate ester and mixtures such as those designated as N-10, H-10 or X-10 as supplied by Findley Adhesives, Incorporated, of Milwaukee, Wisconsin. These materials are stable to the pH conditions of the body (or when cushioned against body fluids), but will break rapidly in the toilet water during the draining process (excess water).

Another mechanism which can be used to trigger degradability in water is ion sensitivity. Certain polymers contain acid-based components (R-COO or R-S03) which are held together by hydrogen bonding. In a dry state, these polymers remain solid. In an aqueous solution which has a relatively high cation concentration, such as urine, the polymers will still remain relatively intact. However, when the same polymers are then exposed to higher amounts of water with a diluted ion content, such as can be found in the toilet bowl, the cation concentration will be diluted and the hydrogen bond will begin to break. When this happens, the polymers themselves will begin to break in the water. See, for example, U.S. Patent No. 4,419,403 to Varona, which is incorporated herein by reference in its entirety. Polymers that are stable in solutions with high cation concentrations (e.g., baby or adult urine and menstrual fluids) can be sulfonated polyesters as supplied by Eastman Chemical Company, of Kingsport, Tennessee under AQ29 codes. , AQ38, or AQ55. The Eastman AQ38 polymer is composed of 89 mole percent isophthalic acid, 11 mole percent sodium sulfoisophthalic acid, 78 mole percent diethylene glycol and 22 mole percent 1,4-cyclohexanedimethanol. It has a nominal molecular weight of 14,000 Daltons, an acid number of less than 2, a hydroxyl number of less than 10, and a glass transition temperature of 38 ° C. Other examples may be mixtures of copolymers of polyvinyl alcohol mixed with polyacrylic or methacrylic acid or polyvinylmethyl ether mixed with polyacrylic or methacrylic acid. Eastman polymers are stable in solutions with higher cation concentrations, but will break easily if placed in an excess of sufficient water such as tap water to dilute the ion concentration.

Other polymers that are stable at high ion concentrations include "dispersed water dispersible polymers". By this it is meant that when the polymer is exposed to a trigger component, such as, for example, the sodium chloride ion or the sodium sulfate ion, at a first level of concentration found in the tap water, the polymer disperses or disintegrates in no more than 30 minutes. However, when the polymer is exposed to the same trigger component at a second higher concentration level typically found in body fluids, such as adult or infant urine, the forming polymer The first component remains stable and does not disperse. For example, suitable examples of such a first component include water-dispersible polyester or polyamide polymers, copolymers, such as the copolyester polymers available from National Starch and Chemical Company under the product designations 70-4395 and 70-4442. . The inventors of the present invention have discovered that water dispersible fibrous nonwoven compounds, having a component comprising a water dispersible polymer fired are insensitive to the presence of a particular trigger component at a level concentration found in the urine, but which are highly sensitive to and dispersed in a period not exceeding not more than 30 minutes in the presence of the same trigger component at a different lower concentration level typically found in excess tap water, as found in the toilet bowls. Thus, the water dispersible fibrous nonwoven composites formed from or incorporating the polymer fibers of the present invention are not affected in terms of dispersibility when insulted with body fluids such as urine, but when discarded in water. of the normal key tend to break and separate as the dispersible polymer dispersible in water triggers.

Still other means to make a polymer degradable in water is through the use of a change of temperature. Certain polymers exhibit a cloud point temperature. As a result of this, these polymers will precipitate out of a solution at a particular temperature which is the cloud point. These polymers can be used to form fibers which are insoluble in water above a certain temperature but which will be soluble and therefore degradable in water at a lower temperature. As a result of this, it is possible to select or mix a polymer that will not degrade in the fluids of the body, such as urine, at or near body temperature (37 ° C) but will degrade when it is Place in water at temperatures below the body temperature, for example, at room temperature (23 ° C). An example of such a polymer is polyvinyl methyl ether which has a cloud point of 34 ° C. When this polymer is exposed to body fluids such as urine at 37 ° C, it will not degrade since this temperature is above the cloud point (34 ° C). However, if the polymer is placed in water at room temperature (23 ° C), the polymer will return, over time, to a solution as it is now exposed to water at a temperature below its cloud point. Consequently, the polymer will begin to degrade.

The mixtures of the polyvinyl methyl ether and the copolymers can also be considered. Other cold water soluble polymers include the graft copolymers of poly (vinyl alcohol) supplied by Nippon Synthetic Chemical Company, Ltd. of Osaka, Japan which are encoded Ecomaty AX2000, AX10000 and AX300G.

Other polymers are degradable in water only when exposed to sufficient amounts of water. Therefore, these types of polymers may be suitable for use in low water volume solution environments such as, for example, panty liners, light incontinence products, and baby or adult cleaners. Examples of such materials may include aliphatic polyamides NP2068, NP2074 or NP2120 as supplied by H. B. Fuller Company of Vadnais Heights, Minnesota.

The data relating to meltblowing and DSC thermal analysis for these three polymers are given in Table I.

TABLE 1 * Test Method ASTMD D-1238-906 (2. 16 kg load at 190 ° C for polyethylene) Having described the various components that can be used to form a non-woven composite structure fibrous dispersible in water according to the present invention, examples of various processes which can be used to form such materials will now be described. A process for forming water dispersible fibrous nonwoven fabric structures according to the present invention is shown in Figure 1 of the drawings. In this drawing, a water degradable polymer is extruded through a die head 10 into a stream of primary gas 11 heated at high velocity (usually air) supplied from nozzles 12 and 13 to attenuate the melted polymer. in somewhat continuous and long fibers. When these water degradable reinforcing fibers are formed, the primary gas stream 11 is fused with a secondary gas stream 14 containing the individualized wood pulp fibers or other particulate materials including to integrate the two fibrous materials into a non-composite structure. unique fibrous woven. The apparatus for forming and delivering the secondary gas stream 14 including the wood pulp fibers can be an apparatus of the type described and claimed in United States Patent Number 3,793,678 issued to Appel. This apparatus comprises a conventional pick-up roller 20 having the pick-up teeth for converting the pulp sheets 21 into the individual fibers. The pulp sheets 21 are radially fed, for example, along a radius of pick-up roller, to the pick-up roller 20 by means of the rollers 22. By converting the teeth on the roller 22 to the pulp sheets 21 into individual fibers, the resulting separated fibers are carried downward toward the primary air stream through a duct or forming nozzle 23. A box 24 covers the take-up roll 20 and provides a duct 25 between the box 24 and the surface of the collector roller. The process area is supplied to the pickup roller in the duct 25 through the duct 26 in a sufficient amount to serve as a means to carry the fibers through the duct 23 at a rate approaching that of the collecting teeth. The air can be supplied by conventional means, such as, for example, a fan.

As illustrated in Figure 1, the primary and secondary gas streams 11 and 14 are preferably moving perpendicular to one another at the melting point, although other melting angles may be employed if desired to vary the degree of mixing and / or to form concentration gradients through the structure. The velocity of the secondary stream 14 is essentially slower than that of the primary stream 11 so that the integrated stream 15 resulting from the melt continues to flow in the same direction as the primary stream 11. The melting of the two streams is somewhat as an aspirant effect whereby the fibers in the secondary stream 14 are pulled into the primary stream 11 as the outlet of the duct 23 passes. If a uniform structure is desired, it is important that the difference in The velocity between the two gas streams is such that the secondary stream is integrated with the primary stream in a turbulent manner so that the fibers in the secondary stream are completely mixed with the meltblown fibers in the primary stream. In general, increasing the speed differences between the primary and secondary currents results in a more homogeneous integration of the two materials while the lower velocities and the smaller velocity differences will produce concentration gradients of the components in the non-woven composite structure. fibrous. For maximum production rates, it is generally desirable that the primary air stream have an initial sonic velocity within the nozzles 12 and 13 and that the secondary air stream has a subsonic velocity. As the primary air stream leaves the nozzles 12 and 13, it expands immediately resulting in a decrease in velocity.

The deceleration of the high velocity gas stream leading to the water degradable meltblown fibers formed by blowing with light melt to the fibers of the pulling forces which form them essentially from the mass of water degradable polymer. By relaxing the water-degradable reinforcing fibers, they are in a better position to track small particles and become entangled and capture relatively short pulp absorbent fibers. others while both fibers are placed and suspended in the gaseous medium. The resulting combination is an intimate mixture of wood pulp fibers and water degradable reinforcing fibers integrated by physical entrapment and mechanical entanglement.

The attenuation of water-degradable reinforcing fibers occurs before and after the tangle of these fibers with the pulp fibers. In order to convert the fiber mixture into the integrated stream 15 into a fibrous nonwoven structure, the stream 15 is passed into the pressure point of a pair of vacuum rollers 30 and 31 having the foraminous surfaces continuously rotating over a pair of fixed vacuum nozzles 32 and 33. Upon entering the integrated stream 15 at the pressure point of the rollers 31 and 33, the carrier gas is sucked into the two vacuum nozzles 32 and 33 while the fiber mixture it is held and compressed slightly by the opposite surfaces of the two rollers 30 and 31. This forms a self-supporting and integrated fibrous non-woven composite structure 34 having sufficient integrity to allow it to be removed from the pressure point of the vacuum roller and take it to the roller 35.

The containment of wood pulp fibers in the integrated reinforced fiber matrix is obtained without any further processing or treatment of the structure composite placed by air. However, if it is desired to improve the strength of the fibrous nonwoven composite structure 34, such as, for example, of a cleaner, the composite fabric or structure 34 can be etched or bonded using heat and / or pressure. Engraving can be achieved using, for example, ultrasonic bonding and / or mechanical bonding through the use of patterned and / or plain bonding rolls which may or may not be heated. Such joining techniques are well known to those skilled in the art. In Figure 1 the composite structure 34 is passed through an ultrasonic bonding station comprising an ultrasonic calender head 40 vibrating against an anvil roller with pattern 41. The bonding conditions (e.g., pressure, velocity, input strength) as well as the bonding pattern can be appropriately selected to provide the desired characteristics in the final product. See figure 2.

The relative weight percentages of the water degradable reinforcing fibers and of the absorbent fibers can be varied according to the particular end use. Generally speaking, increasing the percent by weight of the water degradable reinforcing fibers will increase the tensile strength in general and the integrity of the resulting fibrous composite nonwoven structure.

Another formation process which can be used to form the water dispersible fibrous nonwoven compounds according to the present invention is shown in the figure 3 of the drawings. An exemplary apparatus for forming an abrasion-resistant fibrous non-woven composite structure which is represented generally by the reference number 110 is shown in Figure 3. In the formation of the fiber-resistant non-woven composite abrasion-resistant structure of the present invention, pellets or flakes, etc. (not shown) of a thermoplastic polymer are introduced into a pellet hopper 112 of one or more extruders 114.

The extruders 114 have the extrusion screws (not shown) which are driven by a conventional drive motor (not shown). As the polymer advances through the extruders 114, due to the rotation of the extrusion screw by the drive motor, the polymer is progressively heated to a molten state. The heating of the thermoplastic polymer to the melted state can be achieved in a plurality of discrete steps with its temperature being generally high as it advances through the discrete heating zones of the extruder 114 to the meltblowing dies 116 and 118 respectively . The meltblowing dies 116 and 118 may still be another heating zone where the temperature of the thermoplastic resin is maintained at a high level for extrusion.

Each meltblown matrix is configured so that the two streams of the attenuation gas usually heated by matrix converge to form a single gas stream which carries and attenuates the melted threads of degradable polymer in water, as the threads exit. holes or small holes 124 in the meltblown matrix. The melted yarns are attenuated in the fibers 120, or depending on the degree of attenuation, the microfibers, of a small diameter which is usually smaller than the diameter of the holes 124. Thus, each meltblowing matrix 116 and 118 it has a corresponding single gas stream 126 and 128 which contains the attenuated polymer fibers. The gas streams 126 and 128 containing the polymer fibers are aligned to converge in a collision zone 130.

One or more types of secondary fibers 132 and / or of particulates are added to the two streams 126 and 128 of the water degradable thermoplastic polymer fibers or microfibers 120 in the shock zone 130. The introduction of the secondary fibers 132 into the two streams 126 and 128 of the water degradable thermoplastic polymer fibers 120 is designed to producing a graduated distribution of the secondary fibers 132 within the combined streams 126 and 128 of the thermoplastic polymer fibers. This can be achieved by fusing a secondary gas stream 134 containing the secondary fibers 132 between the two streams 126 and 128 of the water-degradable thermoplastic polymer fibers 120 so that all three gas streams converge in a controlled manner.

The apparatus for achieving this fusion may include a conventional pick-up roller arrangement 136 which has a plurality of teeth 138 which are adapted to separate a mat or block 140 from secondary fibers into individual secondary fibers 132. The mat or the secondary fiber block 140 which is fed to the take-up roll 136 can be a sheet of pulp fibers (if desired a mixture of two fiber components of water-degradable thermoplastic polymer and of secondary pulp fibers), a short-fiber mat (if a mixture of two components of water-degradable thermoplastic polymer fibers and secondary staple fibers) or both a sheet of pulp fibers and a short-fiber mat (if desired a mixture of stoneware components of degradable thermoplastic polymer fibers in water, secondary short fibers and secondary pulp fibers). In embodiments where, for example, an absorbent material is desired, the secondary fibers 132 are the absorbent fibers. Secondary fibers 132 can generally be selected from the group including one or more polyester fibers, polyamide fibers, cellulose-derived fibers such as, for example, rayon fibers, pulp fibers of wood and superabsorbent fibers, multi-component fibers such as, for example, multi-component sheath-core fibers, natural fibers such as silk fibers, wool fibers or cotton fibers, or the fibers or electrically conductive mixtures of two or more such secondary fibers. Other types of secondary fibers 132 such as, for example, polyethylene fibers and polypropylene fibers, as well as mixtures of two or more other types of secondary fibers 132 can be used. Secondary fibers 132 can be microfibers or secondary fibers 132 can be macrochibers having an average diameter of from about 300 microns to about 1,000 microns.

The sheets or mats 140 of secondary fibers 132 are fed to the pick-up roller 136 by a roller arrangement 142. After the teeth 136 of the pick-up roller 136 have separated the secondary fiber mat 140 on the separated secondary fibers 132, the individual secondary fibers 132 are brought into the stream of fibers or microfiber from thermoplastic polymer 120 through the nozzle 144. A box 146 encloses the collector roll 136 and provides a conduit or separation 148 between the box 146 and the surface of the teeth 138 of the pick-up roller 136. A gas such as air is supplied to the duct or separation 148 between the surface of the pick-up roller 136 and the box 146 by means of a gas duct 150. The gas duct 150 can enter the duct or partition 148 generally at the joint 152 of the nozzle 144 and the partition 148. The gas is supplied in an amount sufficient to serve as a medium to carry the secondary fibers 132 through the nozzle 144. The gas supplied from the duct 150 also serves as an auxiliary for removing the secondary fibers 132 from the teeth 138 of the collector roll 136. The gas can be supplied by any arrangement conventional such as, for example, an air blower (not shown). It is contemplated that the additives and / or other materials may be added or carried in the gas stream to treat the secondary fibers 132 or to provide the desired properties to the resulting fabric.

Generally speaking, the individual secondary fibers 132 are carried through the nozzle 144 at about the speed at which the secondary fibers 132 leave the teeth 138 of the pickup roller 136. In other words, the secondary fibers 132, when leaving the teeth 138 of the collector roll 136 and entering the nozzle 144 generally maintain their speed in both the magnitude and direction from the point where they left the teeth 138 of the collector roll 136. Such an arrangement which is discussed in greater detail in U.S. Patent No. 4,100,324 issued to Anderson and others helps to essentially reduce fiber flocculation.

The width of the nozzle 144 should be aligned in a direction generally parallel to the width of the meltblown dies 116 and 118. Desirably, the width of the nozzle 144 should be almost the same as the width of the meltblown dies 116 and 118. Usually, the width of the nozzle 144 should not exceed the width of the sheets or mats 140 that are being fed to the pickup roller 136. Generally speaking, it is desirable that the length of the nozzle 144 that separates the picker of the shock zone 130 is as short as the design of the equipment allows.

The pick roller 136 can be replaced by the conventional particulate injection system to form a fibrous nonwoven composite structure 154 containing several secondary particulates. A combination of both particulate and secondary fibers can be added to the water-degradable thermoplastic polymer fibers 120 prior to the formation of the fibrous nonwoven composite structure 154 if a conventional particulate injection system was added to the system illustrated in Figure 3. The particulates may be, for example, carbon, clay, starches, and / or particulate hydrocolloids (hydrogel) commonly referred to as superabsorbents.

Due to the fact that thermoplastic polymer fibers degradable in water in the fiber streams 126 and 128 are still usually semi-squeezed and sticky at the time of incorporation of the secondary fibers 132 into the fiber streams 126 and 128, the secondary fibers 132 are not only mechanically entangled within the matrix that is formed by the degradable fibers in the fibers. water 120 but also thermally bonded or bound to water degradable fibers.

In order to convert the composite stream 156 of degradable fibers into water 120 and the secondary fibers 132 into a fibrous nonwoven composite structure 154 composed of a coherent matrix of the water degradable fibers 120 having the secondary fibers 132 distributed therein, it is located a collector device in the path of the composite stream 156. The collector device may be an endless belt 158 conventionally driven by the rollers 160 and which is rotated as indicated by the arrows 162 in FIG. 3. Other collector devices may be used very well. known to those skilled in the art in place of the endless belt 158. For example, a porous rotating drum arrangement can be used. The fused streams of water degradable fibers and secondary fibers are collected as a coherent matrix of the fibers on the surface of the endless belt 158 to form the fibrous nonwoven composite structure or fabric 154. The vacuum boxes 164 aid in the retention of the matrix on the surface of the band 158. The vacuum can be placed around 2.5 to about 10 centimeters of water column.

The fibrous non-woven composite structure 154 is coherent and can be removed from the web 158 as a self-supporting non-woven material. Generally speaking, the fibrous nonwoven composite structure 154 has adequate strength and integrity to be used without any post-treatments such as pattern bonding and the like. If desired, a pair of pinch rollers or pattern bonding rollers (not shown) can be used to join the parts of the material. Although such treatment can improve the integrity of the fibrous nonwoven composite structure 154 it also tends to compress and densify the structure.

In addition to the above processes, there are a number of other processes which are suitable for making various types of coform materials. For example, McFarland et al., In U.S. Patent No. 4,604,313 issued August 5, 1986, is directed to a process for forming a multi-layer coform material including meltblown fibers and pulp fibers. of wood in a layer and a secondary layer which contains the fibers of blowing with fusion, the fibers of wood pulp and the superabsorbent particles. Another process is described in U.S. Patent No. 4,902,559 issued February 20, 1990, issued to Eschwey et al. This patent describes a process in which the endless filaments are spun through a long spinner in a conduit to form what is most commonly referred to as spunbonded fibers. At the same time, the hydrophilic or the smaller oleophilic fibers are fed into the stream of the spunbonded fibers. Optionally, the superabsorbent particles can also be introduced into the above fiber blend. Both patents of McFarland and others and that of Eschwey and others are hereby incorporated by reference in their entirety.

Having described the various components and processes that can be used to form the fibrous nonwoven composite structures dispersible in water according to the present invention, a series of examples were prepared to demonstrate the present invention. Note that examples 1-3 are not examples of the invention, examples 4 and 5 are examples of water-dispersible, water-dispersible polymer film which can be used in the present invention, and examples 6 and 7 are examples of fibrous nonwoven structure compounds according to the present invention.

EXAMPLES Example I In Example I, fibrous non-woven composite structures dispersible in water were made using meltblown material of polyvinyl alcohol copolymer and wood fluff pulp in proportions of 20/80, 30/70, and 40/60 percent by weight (meltblown / pulp) based on the total weight of the fibrous non-woven composite structure. The polyvinyl alcohol copolymer has the code name Ecomaty AXIOOOO and was manufactured by Nippon-Gohsei of Osaka, Japan. The melt flow rate of this AXIOOOO copolymer was 100 grams per 10 minutes at a temperature of 190 ° C under a load of 2.16 kilograms using the Test Method ASTM D-1238. The softening temperature of the AXIOOOO copolymer was 180 ° C but it was best processed at 210 ° C to make the meltblown microfibers. The wood fluff pulp had the code number NF405 as received from Weyerhauser Corporation of Federal Way, Washington. The absorbent structure was produced using a twin extruder and a pulp fiberizer system as shown in Figure 3. The coformmed compounds were formed on either a porous tissue carrier sheet or a non-woven polypropylene nonwoven carrier sheet. by spinning. Optionally, the coform compounds can be formed directly on a forming wire. The base weights of the coformmed absorbent structures were 190 grams per square meter (gsm). The absorbent structures were then patterned in a separate process using a heated calender pressure point with a total binding area of approximately 20 percent. When the coformed absorbent was placed in water at At room temperature and stirred, the meltblown fibers were dissolved and the fabric broke in less than about one minute and typically in less than 30 seconds. The 20/80 ratio of fabric was placed in a consumer study with adult women in an intermenstrual panty liner test and the coformed absorber was found to be able to withstand small fluid loads of urine and menstrual fluids for periods of up to six hours.

Example II In Example II a fibrous non-woven structure dispersible in water was made using a meltblown material of water-soluble polyamide polymer and wood pulp fluff in a 30/70 weight ratio of melt blown / fluff. The polyamide polymer had a code number NP 2068 as received from H. B. Fuller Company of St. Paul, Minnesota. The viscosity of the NP 2068 polymer was 95 Pascals-seconds at a temperature of 204 ° C. The smoothing temperature range of the NP 2068 polymer was 128 ° -145 ° C but was best processed at 210 ° C to make the meltblown microfibers. The pulp of wood pulp has the code number NF405 as received from Weyerhauser Corporation of Federal Way, Washington. The absorbent structure was produced in the same manner as in Example I. The coform compound was formed on a porous tissue carrier sheet. The base weight of The absorbent structure coformada was 190 grams per square meter. When the coformed absorbent was placed in water at room temperature and stirred, the meltblown fibers were dissolved and the fabric broke in less than one minute and typically in less than 30 seconds.

Example III In Example III a fibrous non-woven composite structure dispersible in water was made using meltblown water-soluble polyamide polymer and wood pulp flux at a melt / wipe weight ratio of 30/70. The polyamide polymer had the code number NP 2074 as received from H.B. Fuller Company, of St. Paul, Minnesota. The viscosity of the NP 2074 polymer was 290 Pascal-seconds at a temperature of 204 ° C. The smoothing temperature range of the NP 2074 polymer was 133 ° -145 ° C but this was best processed at 210 ° C to make the meltblown microfibriers. The wood fluff pulp had a code number NF405 as received from Weyerhauser Corporation of Federal Way, Washington. The absorbent structure was produced in the same manner as in Example I. The coform process was formed on a porous tissue carrier sheet and the basis weight of the coformmed absorbent structure was 190 grams per square meter. When the coformed absorbent was placed in water at room temperature and stirred, the blowing fibers with fusion they dissolved and broke in less than one minute and typically in less than 30 seconds.

To further demonstrate the present invention, experimental pantyliners were made using the water degradable coform materials delineated above in Examples I to III and compared with panty liners containing conventional coform material. The construction of the conventional pant liner included a polyethylene separating film, a thermally bonded polypropylene spun liner of 13 grams per square meter and a coform material of 190 grams per square meter as the absorbent core. The coform material composed of 30 percent by weight of polypropylene meltblown fibers having an average fiber diameter of about 5 microns and 70% by weight based on the weight of the fibers of wood pulp of absorbent core. The meltblown fibers of polypropylene and wood pulp were intimately mixed with one another to form the absorbent core. To assemble the pant liner structure, a water-based adhesive was used to laminate the polyethylene film on one side of the coform material and the polypropylene spunbonded liner was thermally etched on the other side of the coform material. On the outer surface of the polyethylene film separator, an adhesive strip was applied to a garment to secure the product to the wearer's undergarment. This laminate It formed the control since it did not contain any water-degradable reinforcing fibers but instead used blowing fibers with polypropylene melting as reinforcing media. A further description of such products can be found in U.S. Patent No. 3,881,490 issued to Whitehead et al. And in U.S. Pat. No. 247,368 to Whitehead, both of which are incorporated herein by reference. reference in its entirety.

The materials of the present invention of the Examples I to III were also formed into pant lining of the same general description as above. Instead of 190 grams per square meter of the polypropylene coform material in the control, 190 grams per square meter of 30 percent water-degradable reinforcing fibers / 70% by weight of wood pulp fiber coform were used according to Examples I, II and III. In addition, the polyethylene separator was replaced with a water degradable film and the separator film was attached to the coform absorbent core by means of a hot melt adhesive instead of a water-based adhesive.

Twenty samples each of the four pantiliners including the control underwent the drainage test in the toilet. In the test, the individual samples were placed in a 3.5-gallon toilet and left remain in the toilet for 30 seconds before draining. The control which contained the standard coform material was only drained in six of the twenty samples thus indicating that only 30% of these panty liners would be drained in a 3.5 gallon toilet. In contrast, with the three types of panty liners using the water dispersible materials of the present invention, all twenty samples of each material were drained. As a result of this, the materials were 100% drainable. A visual observation that was made while this test was being carried out was that the panty liners according to the present invention absorbed the water almost immediately and then sank directly to the bottom of the toilet rate. In contrast, the control screen liners which contained the polypropylene fibers (which have a density of less than 1 gram per cubic centimeter and a polyethylene separator film with a density of less than 1 gram per cubic centimeter) floated on the surface of the water in the toilet bowl. Consequently, the hydraulic driving force acting on the control product was much lower than that acting on the experimental products. This demonstrated the lack of drainability of the control product because it can not perform the driving force of the primer jet in the toilet.

In addition, five samples of the control and of the panty liners containing the materials of Examples I to III were separately introduced into a moving water system having a velocity of approximately 0.6 meters per second. In less than one minute, the absorbent core material of examples I to III were completely broken to the point that it was unrecognizable. In contrast, the absorbent core of the control remained essentially intact even after 30 minutes of exposure time.

EXAMPLE IV In Example IV, film samples formed from National Starch 70-4442 film were made using a Carver press and polymer film press fittings (see Figures 4 to 7) and then carried out the stress tests. The film pressure fitting included a fixed female bottom plate and a male top plate, both of which were electrically heated and cooled with water. The depth of the lower plate was controlled by placing wedges 0.03302 centimeters (cm) thick on both support arms of the film pressing attachment.

The upper and lower plate temperatures were set at 127 ° C. A silicon release liner was placed below the polymer sample on the bottom plate. A silicon release liner was also placed on the polymer sample. The plates were placed to exert a pressure of 7.030 kilograms per square meter (kg / m2). By achieving 7.030 kg / m2, the pressure was released, rose back to 7.030 kg / m2 and was maintained until the plate temperatures fell around 35 ° C. The films pressed with the released liners were then removed from the fixture. The resulting film samples had a thickness of about 0.0127 cm and were 25 cm long and 20 cm wide.

The rectangular film samples were cut having a gauge length of 63.5 millimeters (mm) and a gauge width of 19.05 mm. The gauge thickness as shown in Table II here, was measured with a Starret micrometer # 216. A Liveco Vitrodyne 1000 tension tester with submersible jaws and faces (available from John Chatillon &Sons, 7609 Business Park Drive, Greensboro, North Carolina) was used to measure peak voltage. The jaw separation speed was set at 3,000 micrometers per second. The jaw spacing was set at 32,000 micrometers. The test options were established in autoregress. The force limit was set to 100%. The cutoff frequency was set to 200 Hertz. All peak stress and thickness stress values shown in Table II are averages, based on at least measurements n = 4.

The first series of samples (sample 1) was tested for peak stress stress in a dry condition.

That is, the films of sample 1 were not placed in or subjected to an aqueous solution or aqueous medium before the test.

The second series of samples (sample 2) were tested for peak tensile stress after being immersed for 1 minute in 2,000 milliliters (ml) of blood bank salt water, 0.85% NaCl, catalog No. B3158-1 ( available from Baxter Healthcare Corporation).

The third series of samples (sample 3) was tested for peak strain after submerging for 1 minute in 2,000 milliliters of salt water from a blood bank, 0.85% NaCl, catalog No. B3158-1 with 1.0% sulfate anion added.

The fourth series of samples (sample 4) was tested for the peak stress stress after being submerged for 1 minute in 2,000 milliliters of deionized water having a strength greater than or equal to 18 megaohms.

The fifth series of samples (sample 5) was tested for the peak strain stress after having submerged for 30 minutes in 2,000 milliliters of deionized water having a strength greater than or equal to 18 megaohms.

The peak stress and strain data for samples 1-7 were as follows: TABLE II Thickness Number Sample Effort No. Measurements (micrometers) Peak tension (Mpa) 1 5 0.322 4.51 2 5 0.291 4.32 3 4 0.201 4.43 4 5 0.326 0.07 5 5 0.216 0.00 The peak stress stress data shown here illustrates that film samples formed from the National Starch copolyester polymer 70-4442 are significantly affected by the presence of the sulfate anion (a cosmotrope) in solution, which tends to accumulate or increase the resistance to stress at high levels of concentration, such as those found in the urine of the infant or adult. However, in the presence of excess water, in which the concentration of the sulfate anion is below the concentration of critical precipitation (e.g. of about 100 parts per million), the copolyester polymer (or copolymer) is precipitated from the solution, weakening the film strength so that the film tends to disperse.

EXAMPLE V In this example, samples of films formed from National Starch 70-4442 polymer were tested for dispersion in deionized water as compared to commercially available bathroom tissue, essentially in accordance with "A simple test for fiber dispersion of wet cut glass in water "published at the 1996 TAPPI Nonwovens Procedures Conference and incorporated herein by reference. Five film samples of 38.1 millimeters long by 38.1 millimeters wide (sample 1 having an average weight of 0.2525 grams were placed in 1500 milliliters of deionized water having a strength greater than or equal to 18 megaohms contained in a 2,000-pound Kimax beaker milliliters, No. 14005. A Fisher Scientific stirrer (Magnetic) catalog No. 11-498-78H was set at a speed of 7 to shake the contents of the weeping vessel.Using a normal timer, the time period was measured from the point in which the agitator was activated until the start of the dispersion occurred, which was defined as the point at which the first piece of the sample film material broke from the remaining part of the sample of film, and until the complete dispersion occurred, which was defined as the point at which the sample film material had been dispersed into pieces having diameters not exceeding about 6.35 millimeters.

Five unique sheets of tissue for bathroom ® Kleenex Premium (sample 2) available from Kimberly-Clark Corporation of Dallas, Texas, each measuring 10.2 centimeters by 11.4 centimeters and having an average weight of 0.3274 grams, underwent the same test procedure and the periods of onset of dispersion and complete dispersion were measured.

Finally, this test procedure was repeated by placing a single sample of film of 38.1 millimeters by 38.1 millimeters (sample 3) made of National Starch 70-4442 polymer, having a weight of 0.2029 grams, in 1,500 milliliters of salt water bank of blood, 0.85% NaCl, catalog No. B3158-1 with 0.1% sulfate anion added. The periods for the onset of dispersion and complete dispersion were measured. As can be seen from Table III given below, no dispersion occurred for a period of 15 minutes, at which time the test was completed.

TABLE III Dispersion start number complete Sample No. Measurements pers. (Sec.) (Seconds) 1 5 0.322 4.51 2 5 0.291 4.32 3 1 None after None after 15 minutes of 15 minutes The results of the test procedures carried out under this example further illustrate that the fibers using the dispersed water dispersible polymer 70-4442, according to the present invention, will be dispersed in the presence of a particular trigger component, such as the sulfate anion, at a concentration level found in excess water, while essentially remaining unaffected when exposed to the same trigger component at a concentration level typically found in body fluids, such as infant urine or of the adult In addition, the dispersion rate compares favorably with that of commercial bathroom tissue products, which are generally placed in normal tap water, such as that found in toilet bowls.

EXAMPLE VI In Example VI, four structures composed of water-dispersible fibrous non-wovens were used using melt-blown water-degradable copolyester melt and ion-flushed wood pulp in percent proportions by weight of 35/65, 30/70, 30/70 and 25/75 (melt blown / pulp) based on the total weight of the fibrous nonwoven composite structure. The copolyester had a code name of 70-4395 and was manufactured by National Starch. The wood fluff pulp had a code number NF405 as received from Weyerhauser Corporation, of Federal Way, Washington. The absorbent structure was produced using a twin extruder and a pulp fiberizing system as shown in Figure 3. The coformmed compounds were formed directly on a forming wire using a melting temperature of about 170 ° C. The base weights of the coformed absorbent structures were 75, 190, 150 and 75 grams per square meter (? Gsm) respectively. The absorbent structures were then patterned in a separate process using a calender pressure point heated to about 40-50 ° C with a total binding area of about 20%. When the coformed absorbent was placed in water at room temperature and stirred, the meltblown fibers dissolved and the fabrics broke in less than 15 minutes.

Thus it can be seen that the fibrous non-woven composite structures dispersible in water of the present invention may be able to provide a wide variety of applications where products are required to disperse rapidly in the water after the intended use cycle. It should also be noted that the present invention is directed to dry and essentially dry applications, for example, in panty liners, where only a small amount, generally 0.25 to 0.5 grams, of fluid is absorbed. The invention will be unsuitable for wet applications such as in wet cleaners where, for example, solutions such as those containing phospholipids and benzoic acid are saturated on a cleaner, since any low ion solution would cause the compound to break. This invention, moreover, does not use (for example, it is essentially free of) water-dispersible reinforcing fibers that can not be fired. Wet applications will be better suited for the invention described in the United States of America patent application 08/774, 417 filed on December 31, 1996 and titled UNDISPURABLE FABRIC AND COFORMED UNIFORM WITH A HYBRID SYSTEM AND A METHOD TO MAKE THE SAME, commonly ceded to Jackson, Mumick, Ono, Pomplun and Wang, with lawyer issue number 12883, which requires non-fusible reinforcing fibers and which is incorporated here in its entirety.

Having thus described the invention in detail, it should be evident that several modifications and changes to the present invention without departing from the spirit and scope of the following clauses.

Claims (23)

R E I V I N D I C A C I O N S

1. A fibrous non-woven composite structure dispersible in water comprising: a matrix of melt-spun water-degradable reinforcing fibers and a multiplicity of discrete absorbent fibers placed within said matrix of melt-spun degradable water-reinforcing fibers wherein the melt-spun fibers further comprise a water-dispersible polymer that remains stable in water. the presence of body fluids and disperses in a period not exceeding 30 minutes in deionized water.

2. The fibrous non-woven composite structure dispersible in water as claimed in clause 1, characterized in that said absorbent fibers are short fibers having average fiber lengths of approximately 18 millimeters or less.

3. The fibrous non-woven composite structure dispersible in water as claimed in clause 1, characterized in that the absorbent fibers are wood pulp fibers.

4. The fibrous nonwoven composite structure dispersible in water as claimed in clause 1, characterized in that it also includes a particulate material within said matrix.

5. The fibrous nonwoven composite structure dispersible in water as claimed in clause 4, characterized in that said particulate material is a superabsorbent.

6. The fibrous non-woven composite structure dispersible in water as claimed in clause 4, characterized in that said particulate material is an odor reducing agent.

7. The fibrous non-woven composite structure dispersible in water as claimed in clause 1, characterized in that said water degradable spunbond reinforcing fibers comprise water degradable polyamides.

8. The fibrous non-woven composite structure dispersible in water as claimed in clause 1, characterized in that said water degradable spunbond reinforcing fibers comprise polyester.

9. The water-dispersible fibrous non-woven composite structure, as claimed in clause 8, characterized in that said melt-spun degradable water-reinforcing fibers undertake a water-dispersible copolyester.

10. A fibrous non-woven composition dispersible in water, as claimed in clause 1, characterized in that said water-degradable spunbond reinforcing fibers are dispersed in a period not exceeding 15 minutes in deionized water.

11. An absorbent article for personal care which includes a fibrous non-woven composite structure dispersible in water as claimed in clause 1.

12. The absorbent article for personal care as claimed in clause 11, characterized in that said article is a cleaner.

13. The absorbent article for personal care as claimed in clause 11, characterized in that said article is a diaper.

14. The absorbent article for personal care as claimed in clause 11, characterized in that said article is a training brief.

15. The absorbent article for personal care as claimed in clause 11, characterized in that said article is a lining for panty.

16. The absorbent article for personal care as claimed in clause 11, characterized in that said article is a sanitary napkin.

17. The absorbent article for personal care as claimed in clause 11, characterized in that said article is an incontinence device.

18. The absorbent article for personal care as claimed in clause 11, characterized in that said article is a wound dressing.

19. The absorbent article for personal care as claimed in clause 11, characterized in that said article is a bandage.

20. A water-dispersible fibrous non-woven composite structure comprising a matrix of water-degradable spunbonded reinforcing fibers and a plurality of particles placed within and held by said matrix, wherein melt-spun water-degradable reinforcing fibers further comprise a polymer dispersible in water having a first peak stress stress in the presence of body fluids, and a second peak stress stress in the presence of deionized water, said second peak voltage stress being at least 90% less than said first peak voltage stress.

21. The fibrous nonwoven composite structure dispersible in water as claimed in clause 20, characterized in that said particles comprise a superabsorbent.

22. The fibrous nonwoven composite structure dispersible in water as claimed in clause 20, characterized in that said particles comprise an odor reducing material.

23. A fibrous non-woven composite structure dispersible in water consisting essentially of a matrix of water-degradable reinforcing fibers, ionically triggerable melt spinning and a multiplicity of absorbent fibers discrete placed within said matrix, wherein said composite structure is dispersed in a period not exceeding 30 minutes in deionized water. SUMMARY Here a fibrous non-woven composite structure most commonly referred to as a coform structure is described. Unlike current coform structures, the material of the present invention is more water dispersible due to the use of the water degradable reinforcing fiber matrix.