MXPA99010830A - Ion sensitive binder for fibrous materials - Google Patents

Abstract

A water soluble polymer binder for binding a fibrous substrate comprises from about 25 weight percent to about 85 weight percent of an unsaturated carboxylic acid/unsaturated carboxylic acid ester terpolymer;from about 5 weight percent to about 35 weight percent of a divalent ion inhibitor;and from about 10 weight percent to about 60 weight percent of a hydrophilic cross-linkable polymer. In a preferred mode of the invention the hydrophilic cross-linkable polymer functions substantially as a divalent ion inhibitor and promotes hydrophilicity of the treated fabric eliminating the requirement of a separate divalent ion inhibitor. The binder composition is soluble in an aqueous environment having a divalent ion concentration less than about 50 ppm and a monovalent ion concentration of less than about 0.4 weight percent. Also disclosed is a water dispersible fibrous fabric having an effective amount of the binder distributed on the fibrous substrate and a method of making a water dispersible fibrous fabric.

Description

ION SENSITIVE AGGLUTANT FOR FIBROUS MATERIALS BACKGROUND OF THE INVENTION The present invention relates to a water dispersible material whose solubility in water depends on the total ionic concentration in water and particularly on the concentration of divalent ions. More particularly, the invention relates to a polymer binder composition which is dispersible in water when the concentration of divalent ions in water is less than about 50 parts per million (ppm) and desirably, the concentration of monovalent ions is less of about 0.4 percent by weight. Advantageously, the polymer composition is insoluble in an aqueous solution having a divalent ion concentration greater than about 50 parts per million. The invention is further directed to a method for making a water dispersible nonwoven fibrous web comprising a fibrous substrate and the ion sensitive binder composition distributed there and the use of the water dispersible nonwoven fibrous web in dispersible personal use products. in water Although the composition and products of the present invention are described herein primarily in connection with advantageous applications as a disposable absorbent article and more particularly, a pre-moistened cleaner, it is to be understood that the present is not limited thereto. In light of the present disclosure, those skilled in the art will recognize a variety of applications in other fields where water dispersion of a fibrous web will be desirable.

Fabrics and fibrous non-woven fabrics are widely used as components of disposable products such as sanitary napkins, diapers, wound dressings, bandages, day care pads and pre-moistened cleansers. The terms "fibrous non-woven fabrics", "fibrous fabrics", "non-woven fabrics", "fabrics" and "fibrous substrates" are used interchangeably herein and include without limitation the methods for making such fabrics and fabrics which may include, but they are not limited to placement by air and wet placement.

Such fabrics, if they are to function effectively, must maintain their structural integrity as well as exhibit satisfactory tensile strength when they are wet or damp. However, it has been recognized that if such non-woven fabrics would essentially lose their tensile strength when exposed to water they become easily dispersible, the waste problems would be substantially eliminated. The products can be easily and conveniently dispersed with agitation of water in a conventional toilet or toilet.

Desirably, the fabrics possess a number of characteristics such as softness and flexibility. The fabric is usually formed by randomly placing dry or wet fibers and by joining them together to form the coherent fabric. In an attempt to provide a protected fabric with specific characteristics in use, previous methods have made the fabric non-dispersible in water. For example, nonwovens have been bound with insoluble resins in the fluid which in part give resistance in use. However, such resins prevent dispersion with agitation of water and drainage of the fabric by rendering the fabric substantially insoluble to water.

With regard to pre-moistened cleaners, special problems arise. Cleaning wipes which are used to cleanse the skin and are commercially known as wipes, wet cleansers or cleansers for women, are formed of paper or non-woven fibrous fabrics treated with polymeric binder. The binder imparts a degree of moisture resistance to the fabric so that the fabric will not lose its tensile strength while stored in an appropriate liquid medium. However, after the cleaner is used, the binder will essentially weaken when exposed to an aqueous environment, such as when the cleaner is placed in a toilet, without clogging the toilet and tubing.

In an attempt to impart dispersibility in water, various binders have been used in the manufacture of the cleaning cloth. For example, cleaning cloths have included as a binder an insoluble soluble polycarboxylic acid alkali polymer and functional derivatives thereof wherein the acid is placed in water and sufficient alkali is added to neutralize essentially all of the acidic groups before applying the binder to the binder. tissue. The fabric saturated with binder is dried and then immersed in a low pH medium where it retains its structural integrity but will still break when the cleaner is immersed in a liquid medium of a sufficiently high pH.

Another binder used has been polyvinyl alcohol combined with a gelation agent or in an insolubilizer such as borax. The borax cross-links at least the surface of the polymer binder before the fabric is dried to give a water-resistant fabric. Such cross-links are reversible, that is, when the concentration of borax is reduced to below a certain level, the degree of cross-linking is so low that the binder becomes water-soluble.

A problem with the aforementioned binders is that in order to prevent the fibrous non-woven fabric from disintegrating before disposal, the cleaner must be kept in a solution having a Ph which can cause skin irritation when the cleaner is used. .

Another binder that is, to a limited extent, soluble in water comprises an unsaturated carboxylic acid / unsaturated carboxylic acid copolymer. The fabric is soluble in water, dispersible in water, or disintegrable in water in an aqueous environment provided that the water is predominantly devoid of divalent ions. However, in those areas where the water is "moderately hard" because the water contains divalent ions such as calcium ions and / or magnesium ions, the cleaning cloths do not require easy dispersion. The water-soluble polymer binder is essentially insoluble to water by the presence of these divalent ions. Even if it is not possible for them to stick to a particular theory, it is believed that "divalent ions cross and reversibly bind the binder, preventing it from dispersing in water." Until now, the adverse effect of the binder has not been recognized. divalent ions present in the aqueous environment on the water solubility of the polymeric binder.

A problem with the aforementioned binder is that they require a relatively long contact time for the storage solution to wet the fibrous web during the high speed conversion process.

Such times can be as long as several hours.

This limits the commercial utility of the binder for use in a moistened cleanser.

Another problem with the aforementioned binder is that it does not have a sufficient end use strength to be used as a cleaner.

Therefore, there is a need for a water soluble binder composition that can be used in an article, such as a cleaner, that is safe to use and that will not be affected essentially by the presence of the divalent ions normally found in moderately hard water. .

SYNTHESIS OF THE INVENTION Briefly, the present invention relates to a water-soluble polymer composition that can be used in a non-woven fibrous web or substrate fabric. The water-soluble polymeric binder composition includes an unsaturated carboxylic acid / unsaturated carboxylic acid terpolymer, a divalent ion inhibitor and a hydrophilic crosslinkable polymer. In a preferred embodiment, the hydrophilic crosslinkable polymer can function as a divalent ion inhibitor and be replaced by it. The water-soluble polymeric binder composition comprises about 25% by weight about 85% by weight of an unsaturated carboxylic acid / unsaturated carboxylic acid terpolymer; from about 5% by weight, about 35% by weight of a divalent ion inhibitor; and from about 10% by weight to about 60% by weight of a hydrophilic crosslinkable polymer. As used herein, "divalent ion inhibitor" means any substance which inhibits the irreversible cross-linking of neutralized acrylic acid units in the base terpolymer by the divalent ions. In a preferred embodiment of the invention the hydrophilic crosslinkable polymer functions essentially as a divalent ion inhibitor so that the binder composition comprises from about 25% by weight to about 85% by weight of an unsaturated carboxylic acid terpolymer / unsaturated carboxylic acid and from about 15% by weight about 75% by weight of the hydrophilic crosslinkable polymer.

Advantageously, the binder composition of the invention is soluble in an aqueous environment having a divalent ion ion concentration of less than about 50 parts per million and a monovalent concentration of less than about 0.4% by weight.

Another aspect of the invention is a fibrous nonwoven fabric that is dispersible in water. The fabric includes a fibrous substrate and the water-soluble binder distributed through the fibrous substrate to bind together with the fibrous material of the fabric. The non-woven fibrous web is dispersible in water in an aqueous environment having a divalent ion concentration of less than about 50 parts per million and a monovalent ion concentration of less than about 0.4% by weight.

Another aspect of the invention is a method for making a nonwoven fibrous fabric dispersible in water. The method includes the steps of contacting a fibrous substrate with an effective amount of the water-soluble binder composition mentioned above so as to bind a substantial amount of the fibers and dry the fabric.

It is an object of the invention to provide a water soluble polymer which is soluble in mild to moderately hard water but which will be insoluble in water having higher divalent ion concentrations around 50 parts per million. As used herein, "moderately hard water" means water which has a total concentration of from about 25 parts per million to about 50 parts per million of divalent ions. The most limiting examples of divalent ions include calcium and / or magnesium ions. As used herein, mild water has a divalent ion concentration of less than about 25 parts per million and very hard water has a divalent ion concentration of more than about 50 parts per million.

It is another object of the invention to provide a nonwoven fabric that is dispersible in mild to moderately hard water having a concentration of divalent ions less than about 50 parts per million.

. - - Another object of the invention is to provide a pre-moistened cleaning cloth that is easily dispersible in mild to moderately hard water.

Its other object of the invention is to provide a cleaner which can be dispersed in a normal sewer or in normal septic systems which is water dispersible and which will not clog the pipe or the toilet.

DESCRIPTIONS OF THE PREFERRED INCORPORATIONS The non-woven fabrics prepared according to the invention have a good resistance to dry stress depending on, among other things, the amount of binder applied to the fabric and the manner in which it is applied. The non-woven fabric is resistant to abrasion and has a significant tensile strength in aqueous solutions containing more than about 50 parts per million divalent ions. However, the non-woven fabric is dispersible in soft to moderately hard water. Due to this latter property, the non-woven fabrics of the invention are very suitable for disposable products such as sanitary napkins, diapers and dry and pre-moistened wipes which can be thrown in a toilet after use.

The binder of the present invention provides for the breaking of the cleaning cloth after dispersing it with water in a toilet because in the tap water, the binder decreases and preferably loses the bond strength between the binder and the fibers. However, the binder has a substantial strength to keep the non-woven fabric together during the lifetime and during use. According to an embodiment of the invention, the water-soluble binder composition comprises from about 25% by weight of about 85% by weight of the unsaturated carboxylic acid / unsaturated carboxylic acid terpolymer; from about 5% by weight about 35% by weight of a divalent ion inhibitor; and from about 10% by weight of about 70% by weight of the cross-linked hydrophilic polymer. Desirably, the water-soluble binder composition comprises from about 40% by weight about 75% by weight of the unsaturated carboxylic acid / unsaturated carboxylic acid terpolymer, from about 5% by weight to about 20% by weight of the ion inhibitor. divalent and from about 10% by weight about 50% by weight of the hydrophilic crosslinkable polymer.

In a preferred embodiment of the invention, the hydrophilic crosslinkable polymer functions essentially as a divalent ion inhibitor thereby eliminating the use of a separate divalent ion inhibitor. Advantageously, the hydrophilic crosslinkable polymer promotes the hydrophilicity of the treated fabric. Thus, the water-soluble binder composition comprises from about 25% by weight about 85% by weight of an unsaturated carboxylic acid / unsaturated carboxylic acid terpolymer and from about 15% by weight about 75% by weight of a cross-linked hydrophilic polymer. Desirably, the water-soluble binder comprises from about 40% by weight to about 75% by weight of the unsaturated carboxylic acid / unsaturated carboxylic acid terpolymer and from about 25% by weight about 60% by weight of the bondable polymer in hydrophilic cross way.

Advantageously, the binder composition of the invention is soluble in an aqueous environment having a divalent ion concentration of less than about 50 parts per million and a monovalent ion concentration of less than about 0.4% by weight.

Although conventional unsaturated carboxylic acids can be used as a component of the terpolymers, acrylic acid and / or methacrylic acid are preferable. Examples of the monomer components of unsaturated carboxylic acid include acrylic esters and / or methacrylic esters having a group of 18 kilo carbon atoms or a cycloalkyl group of 3 to 18 carbon atoms and it is preferable that Acrylic esters and / or methacrylic esters have a group of 1 to 12 carbon atoms per kilo or a group of 3 to 12 carbon atoms per kilogram are used singly or in combination.

More specifically, examples of the terpolymers include copolymers of 10% by weight to 90% by weight, preferably 20% by weight 70% by weight of acrylic acid and / or methacrylic acid in 90% by weight to 10% by weight, preferably 80% by weight to 30% by weight of acrylic esters and / or methacrylic esters having a group of 1 to 18 carbon atoms or a cyclo to kg group of 3 to 18 carbon atoms in which 1 to 60 mol%, preferably 5 to 50 mol% of acrylic acid and / or neutralized methacrylic acid to form a salt; or copolymers of 30% by weight, 75% by weight, preferably 40% by weight 65% by weight of acrylic acid, from 5% by weight to 30% by weight, preferably from 10% by weight to 25% by weight of acrylic esters and / or methacrylic esters having a group of 8 to 12 carbon atoms per kilo and 20% by weight to 40% by weight; preferably 25% by weight 35% by weight of acrylic esters and / or methacrylic esters having a group of 2 to 4 carbon atoms per kilo in which 1 to 50% per mole, preferably 2 to 40% per mole of acrylic acid are neutralized to form a salt. The molecular weight of the terpolymers is not particularly limited even when the molecular weight by weight of the terpolymers is preferably from 5,000 to 1 million more preferably from 30,000 to 500,000.

Any inorganic base or organic base can optionally be used as a neutralizing agent to neutralize the saturated carboxylic acid component of the copolymers. Examples of the neutralizing agents include inorganic bases such as sodium hydroxide, potassium hydroxide, lithium hydroxide and sodium carbonate, and amines such as monoetalonamine, dietalonamine, diethylaminoethanol, ammonia, trimethylamine, triethylamine, tripropylamine, morpholine. Ethanolamines or sodium hydroxide or a combination of potassium hydroxide and ethanolamines are preferred. The copolymers of this unsaturated carboxylic acid / unsaturated carboxylic acid are described in U.S. Patent No. 5 '384, 189 entitled "Non-Woven Fabric Decomposable in Water", the complete description of which is incorporated herein by reference and is part of it. The terpolymer is available from Lion Corporation of Tokyo, Japan.

Divalent ion inhibitors useful in the invention include sulfonated copolyesters such as Eastman AQ 29D, AQ 38D and AQ 55D (available from Eastman Chemicals, Kingsport, TN); L9158 (available from ATO Findley); crosslinkable poly (ethylene-vinyl acetate) (available from National Starch and Chemical Company of Bridgewater NJ under the trademark ELITE-33) polyphosphates such as sodium tripolyphosphate, phosphonic acids such as ethylene diaminetetra (methylene phosphonic acid), acids amino carboxylic acids such as ethylene diaminotetraacetic acid and nitrilotreacetic acid, hydroxycarboxylic acids such as citric acid; and polyamines such as porpholines.

Hydrophilic cross-linked crosslinkable polymers suitable for use in the invention include polymers having one or more hydrophilic monomers and monomers that are capable of crosslinking. Non-limiting examples of such polymers include: 1) poly (ethylene-vinyl acetate) with substituted N-Acrylamide such as N-Methylol Acrylamide; 2) Acrylamide and N-Copolymers based on acrylamide substituted with crosslinkable monomer such as N-Methylolacrylamide, 3) Copolyacrylates such as hydroxyethylatrilate or poly (ethylene glycol) methacrylate (PEG-MA) with methyl methacrylate or methylacrylate; 4) Poly (ethylene vinyl alcohol) having less than about 3% hydrolysis; and 5) Poly (ethylene glycol) grafted onto other polymers such as polyolefins so that the poly (ethylene glycol) moieties can be crosslinked. A preferred crosslinked polymer is poly (ethylene-vinylacetate) with N-methylolacrylamide available from National Starch and Chemical Company of Bridgwater, New Jersey under the brand name ELITE 33.

In other embodiments of the invention, the binder forms of the present invention can be applied to any fibrous substrate to form a fibrous fabric dispersible in water. The water dispersible fibrous web of the invention is soluble, for example disintegrable or dispersible in an aqueous environment having a divalent ion concentration of less than about 50 parts per million and a monovalent ion concentration of less than about 0.4% by weight. The water dispersible fabric of the invention is particularly suitable for use in a water dispersible product. Suitable fibrous substrates include but are not limited to non-woven and woven fabrics. There are many additions, particularly products for personal use, the preferred substrates are non-woven fabrics due to their absorption of fluids such as blood, menstrual fluids and urine. As used herein, "non-woven fabric" refers to a fabric having a structure of randomly arranged individual fibers or filaments that can be joined together in a mat-like manner. Non-woven fabrics can be made from a variety of processes including, but not limited to, the process of air placement, number placement processes, hydroentanglement processes, basic fiber carding, bonding and spinning. from solution.

The binder formulations are particularly useful for binding fibers of non-woven fabrics placed by air. These air-laid materials are particularly useful for body-to-body liners, for fluid distribution materials, for fluid-taking materials, such as for an emergence material, for absorbent wrapping sheets and cover supply for various products for Personal care dispersible in water. The materials placed by air are particularly useful for use on a pre-moistened cleaning cloth. The base prices for these non-woven fabrics placed by air will vary from around 20 around 200 grams per square meter (gsm) with the basic fibers having 2-3 denier and a length of 6-15 millimeters. Picking materials require better elasticity and superior fluffiness so that basic fibers having about 6 denier or larger are used to make these products. A desirable final density for the shoot emergence materials is between about 0.025 grams per cubic centimeter (G / CC) at about 0.050 G / CC. The fluid distribution materials will have a higher density, in the desired range of around 0.10 to about 0.20 G / CC using fibers from a lower denier, the most desirable fibers have a denier of less than about 1.5. Cleaners generally have a density of about 0.05 g / cc to about 0.1 g / cc and a basis weight of about 60 grams per square meter to about 90 grams per square meter.

The nonwoven fabric itself can be formed of natural fibers, synthetic fibers and combinations thereof. The choice of fibers will depend, for example, on the cost of the fiber and the final intended use of the finished fabric. Non-limiting examples of suitable fibers, which may be used alone or in combination to form the substrates, include cotton, linen, jute, wool, wood pulp, regenerated cellulose fibers such as viscose, rayon, modified cellulose fiber such as cellulose acetates or synthetic fibers derived from polyvinyl alcohol, polyesters, polyamides, polyacrylics, etc. Mixtures of one or more of the fibers also mentioned may also be used if desired.

For cleaners, the non-woven fabric is desirably formed of relatively short fibers such as wood pulp fibers. The minimum length of the fibers depends on the method selected to form the non-woven fabric. Where the non-woven fabric is formed by the wet or dry method the fiber length is desirably from about 0.1 millimeters to 15 millimeters. It has been determined that when a number of fibers having a length greater than about 15 millimeters are placed in a dispersible fabric with water agitation their length tends to form fiber strings which are undesirable in a dispersible material with water agitation. Desirably, the non-woven fabrics of the invention have a relatively low wet cohesive strength when they are not joined together by an adhesive or binder material. When such non-woven fabrics are joined together by an adhesive which loses its bond strength in the tap water and in a sewer water, the fabric will be easily broken by the agitation provided by the dispersion in water dispersion and the movement through the sewer pipes.

The non-woven fabric of the present invention may be formed of a single layer or multiple layers. In the case of multiple layers, the layers are generally placed in a juxtaposed or surface-to-surface relationship and all or a portion of the layers can be joined to the adjacent layers. The non-woven fabric can also be formed of a plurality of separate non-woven fabrics wherein the separated non-woven fabrics can be formed of single or multiple layers. The binder can be distributed over the non-woven fabric as a single application or where there are multiple layers, each individual layer can be separately subjected to a binder application and then combined with other layers in a juxtaposed relationship to form the finished non-woven fabric .

The binder composition can be applied to the non-woven fabric by any known process of application. The binder can be applied to the non-woven fabric, by, for example, spraying, embedding, printing, coating, or any other technique. When the binder has been applied to the non-woven fabric as to retain the integrity of the fabric, it is necessary to disperse the binder in essentially all of the fabric as to cover essentially all fiber joints. Desirably, the binder is dispersed in the non-woven fabric so that from about 80% to 100% of the fiber joints are covered by the binder. More desirably, the binder is dispersed in the non-woven fabric so that from about 95%, 100% of the fiber joints are covered by the binder.

Another embodiment of the invention is a method for making a non-woven fabric dispersible in water. The method includes the steps of contacting the fibrous substrate with an effective amount of the binder formulas of the present invention so as to bind a substantial amount of the fibers. The nonwoven fabric is then dried to form a fibrous fabric dispersible in water. For ease of application of the binder to the non-woven fabric, the binder can be emulsified, dispersed or dissolved in water or in a solvent such as methanol, ethanol or the like, with the water being the preferred carrier. The binder can have from about 1% by weight to about 30% by weight of solids and more desirably, from about 2.5% by weight to about 20% by weight of solids.

Based on the weight of the fabric, the binder can be distributed or "aggregated" to the non-woven fabric in an amount of from about 1% about 50% by weight, desirably from about 5% by weight to about 30% by weight and more desirably from about 8% by weight to about 25% by weight. Where the amount of binder is less than the amount mentioned above, the resulting nonwoven fabric has insufficient mechanical strength. Alternatively, where the amount of the binder is greater than the amount mentioned above, the resulting nonwoven fabric does not have a high smoothness and good feel.

The binder composition may contain plasticizers such as glycerol; sorbitol; emulsified mineral oil; benzoate esters; polyglycols such as, polyethylene glycol, polypropylene glycol and copolymers thereof; decanoyl-N-methylglucamide; tributylsitrate; and tribuutosytylphosphate added to the solution containing the binder composition but this is not preferred. The amount of the plasticizer varies according to the desired softness of the non-woven fabric but can generally be added in an amount from 0% by weight to about 10% by weight based on the weight of the fabric.

Perfumes, dyes, antifoams, bactericides, bacteriostats, active surfactants, thickening agents, fillers, as well as other water-soluble binders such as polyvinyl alcohol, aqueous dispersions of, for example, polyvinyl chloride, polyacrylates, of the polymethacrylates, the acrylate and methacrylate copolymers, the acrylic acid polymers, the methacrylic acid or a salt thereof and the carboxymethyl cellulose can also be incorporated or into the binder if desired.

Once the binder composition is applied to the fabric, the fabric is dried by any conventional means such as by the use of air drying ovens. Once dry, the coherent fibrous fabric exhibits an improved tensile strength when compared to gives tensile strength of a similar fabric placed wet or placed dry but not treated. For example, the tensile strength of the fabric can be increased by at least 25% compared to the tensile strength of the untreated fabric.

More particularly, the resistance to said tension of the fabric can be increased by about 100% and even more particularly the resistance to said tension of the fabric can be increased by at least about 500% as compared to an untreated fabric. However, very disadvantageously, the fabric will disintegrate or be disintegrable when placed in soft to moderately hard cold water and shaken. As used herein "disintegrate", "disintegrable", "dispersible in water" are terms used interchangeably to describe the breaking separation into multiple parts wherein the fabric, after about 90 minutes in tap water, is separated into multiple pieces. Each piece of the fabric has an average size of less than about 50%, desirably less than about 40% and more desirably less than about 30%, relative to the size prior to dispersion. Desirably, the fabric will disintegrate after about 60 minutes and more desirably after about 30 minutes.

A nonwoven fabric suitable for conversion to a cleaning cloth or any other disposable product described above may be any of the type used for such an article. The finished cleaning cloths can be individually packaged, preferably in a condition folded in a moisture proof envelope or packaged in containers containing any desired number of pre-folded sheets and stacked in a water approved package with a wetting agent applied to the cleaning cloth. The moistened cleaning cloth may contain a wetting agent. In relation to the weight of the dry cloth, the cleaning cloth may contain from about 10%, about 400% and desirably from about 100% to about 300% of the wetting agent. The cleaning cloth must maintain its desired characteristics over the periods of time involved in the warehouse, transport, retail display and storage by the consumer. Therefore, shelf life can vary from 2 months to 2 years.

Various forms of waterproof envelopes for containing wet packed materials such as cleaners and wipes and the like are well known in the art. Any of these may be employed in packing the pre-moistened wiping cloths of the present invention.

The non-woven fabric of the present invention can be incorporated into such absorbent products of body fluid as sanitary napkins, diapers, surgical bandages, tissue and the like. The binder is such that it is not dissolved when it is contacted with such body fluids since the concentration of the divalent ions in the fluids is above the level of the solution. The non-woven fabric retains its structure, smoothness and exhibits a satisfactory hardness for practical use. However, when contacted with water having a concentration of divalent ions of up to about 50 parts per million the binder is dispersed. The non-woven fabric structure is then easily broken and dispersed in the water.

The present invention is illustrated by the following examples which should not be construed in any way as imposing limitations on the scope of the invention described herein.

Comparative example 1 A binder solution having 52.6% by weight of an unsaturated carboxylic acid / unsaturated carboxylic acid ester terpolymer (available from Lion Corporation, of Tokyo, Japan under the trademark SSB-3b) was formulated; 42.8% by weight of code L9158 (available from ATO Findley, Wauwatosa, Wl) as a divalent ion inhibiting agent; and 4.6% by weight of the non-crystallizing class of sorbitol (available from Pfizer) as a plasticizer was prepared by dissolving the resin in water to give a solution containing about 13% by weight solids.

From twenty to about twenty-five percent by weight, based on the dry weight of the non-woven substrate, of the aforementioned formula was sprayed on one side of the non-woven fibrous substrate placed in wet containing 60% by weight of basic fibers of polyethylene terephthalate (PET) and 40% by weight of Abaca pulp fiber (available from Hanson &Orth, in Wilmington, North Carolina). The resulting fabric was then dried in a forced air oven at 105 ° C for 10 minutes. The fabric was immersed for 2 minutes in a small dish having 50 milliliters of a test solution having a concentration of divalent ions (Ca ++) of 100 parts per million. The fabric was stable in the test solution but was found to be dispersible in cold tap water after 15 minutes.

The tensile strength of the saturated fabric mentioned above was determined by a modified test procedure ASTM-D5034-11 (1994). The saturated fabric had a width dimension of 25.4 millimeters and a length dimension of 152 millimeters. The procedure was modified to use a Sintech tension tester with a jaw separation of 100 millimeters and a transverse separation speed of 30.5 cm. per minute. The tensile strength of the fabric saturated in the machine direction (MD) was 90 grams per 25.4 millimeters width.

Example 1 A binder solution according to the invention was formulated (formula 1) containing 50% by weight of a terpolymer of unsaturated carboxylic acid / unsaturated carboxylic acid esters (available from Lion under the trademark SSB-3b); 25% by weight of a divalent ion inhibitor (available from Eastman Chemical under the trademark AQ-29D); and 25% by weight of a crosslinked poly (ethylene-vinylacetate) (available from National Starch and Chemical Co., of Bridgewater, New Jersey under the brand name of Elite-33). The formula was diluted to 13% by weight of total solids. From 20 to about 25% by weight, based on the dry weight of the non-woven substrate, the formula was sprayed on one side onto the wet laid substrate described in comparative example 1. The resulting fabric was dried in an oven. forced air at 105 ° C for ten minutes. The fabric was immersed for 2 minutes in a small dish having 50 milliliters of a test solution having a concentration of divalent ions (Ca ++) of 100 parts per million.

Using the above-mentioned procedure for comparative example 1, the tensile strength of the saturated fabric was determined to be 280 grams per 25.4 millimeters wide. The fabric was stable in the test solution but dispersed in water after about 50 minutes.

Comparative Example 2 The binder formula of comparative example 1 was diluted using deionized water for a total solids content of 5.9% by weight. Twenty percent by weight, based on the dry weight of the nonwoven substrate, of this binder formula was sprayed on both sides of a fibrous non-woven substrate containing pulp, Weyerhaueser CF 405 water. The resulting fabric had an overall weight of 68. grams per square meter. The cloth was then dried in an oven set at a temperature of 400 ° Farenheit for 10 to 15 seconds. 185% by weight, based on the dry weight of the fabric, of an aqueous solution having 100 parts per million of divalent calcium ions were added to the fabric.

The tensile strength of the saturated fabric was determined after the test procedures ASTM-D5034-11 (1994). The saturated fabric had a width dimension of 76 millimeters and a length dimension of 152 millimeters. The saturated fabric was placed in a Thwing-Albert tension tester. The tensile strength of the saturated fabric in the cross-machine direction (CD) was 185 grams per 76 millimeters wide. The fabric was stable in the test solution but dispersed in water in about 10 minutes.

The wettability of the dried cloth was determined in the following manner: a drop of deionized water was deposited on the dry cloth in eight random locations using a 10 cms syringe. cubic with a measuring needle 18. The time for the drop of water to penetrate the fabric is recorded with the wettability of the fabric being an average time of eight recorded times. It took 3 mins. and 5 seconds for the dry cloth to absorb the drop of deionized water.

Comparative example 3 The binder formula of comparative example 1 was diluted using deionized water for a total solids content of 5.9% by weight. 20% by weight, based on the dry weight of the non-woven substrate, of this binder formula was sprayed on both sides of a fibrous non-woven substrate containing Weyerhauser CF 405 pulp. The resulting fabric had an overall basis weight of 71 grams per meter square. The resulting fabric was then dried in an oven set at a temperature of 400 ° Farenheit for 10 to 15 seconds. 186% by weight based on the dry weight of the fabric, of an aqueous solution having 100 parts per million of divalent calcium ions, was added to the fabric.

As determined according to the procedure of comparative example 2, the tensile strength of the saturated fabric was 225 grams per 76 millimeters wide. The cloth was stable in the test solution but dispersed in water of about 10 mins.

Example 2 A second binder solution according to the invention (formula 2) containing 65.0% by weight of Lion SSB-3b was formulated; and 35.0% by weight ELITE-33. The formula was diluted to 15.0% by weight of total solids. About 25% by weight based on the dry weight of the non-woven substrate, of the formula 2 was supplied to a non-fibrous non-woven substrate containing pulp, Weyerhauser CF 405 water. The resulting fabric had an overall basis weight of 69 grams per - square meter. The cloth was dried in an oven set at a temperature of 380 ° Farenheit for 10-15 seconds. 250% by weight based on the dry weight of the fabric, of an aqueous solution having 100 parts per million of divalent calcium ions, were added to the fabric.

As determined according to the procedure of comparative example 2, the tensile strength of the saturated fabric was 700 grams by 76 millimeters in width. The fabric was stable in the test solution but was dispersed in water in less than 60 mins.

As determined by the wettability method, comparative example 2, it took 1 minute and 8 seconds on average for the dried fabric to absorb the drop of deionized water.

Example 3 Another binder solution according to the invention (formula 3) containing 65.0% by weight of Lion SSB-3b was formulated; 22.5% by weight of Elite-33; and 12.5% by weight of AQ-29D (divalent ion inhibitor). The formula was diluted to 15.5% total solids.

About 25% by weight based on the dry weight of the nonwoven substrate of formula 3 was applied to the nonwoven fibrous substrate containing Weyerhauser CFF-405 pulp. The resulting fabric has an overall basis weight of 72 grams per square meter. The -level was checked at 380 ° Farenheit for 10-15 seconds. 250% by weight, based on the dry weight of the fabric, of an aqueous solution having 100 parts per million of divalent calcium ions were added to the fabric.

"As determined according to the procedure of comparative example 2, the tensile strength of the saturated fabric was 621 grams per 76 millimeters wide.The fabric was stable in the test solution but was dispersed in water in less than 15 minutes. minutes As determined by the wettability method, comparative example 2, it took less than 10 seconds on average for the dried fabric to absorb the drop of deionized water.

Example 4 Another binder solution according to the invention was formulated (formula 4) containing 39.5% by weight Lion SSB-3b; 32.1% by weight of a divalent ion inhibitor (L-9158 available from ATO Findley); 25% by weight of poly (vinyl ethylene acetate) (ELITE-33); and 3.4% by weight of sorbitol as a plasticizer. The formula was diluted using deionized water at 7.8% by weight of total solids. About 20% by weight, based on the dry weight of the non-woven substrate, of formula 4 was applied to the non-woven fibrous substrate containing Weyerhauser CF-405 pulp. The resulting fabric had an overall basis weight of 66 grams per square meter. The cloth was then dried in an oven set at a temperature of 440 ° Farenheit for 10-15 seconds. 186% by weight, based on dry weight of the fabric, of an aqueous solution having 100 parts per million of divalent calcium ions were added to the fabric.

As determined according to the procedure of Comparative Example 2, the tensile strength of the saturated fabric was 587 grams per 76 millimeters wide. The fabric was not dispersed in water due to the cross-linking of setting with excessive heat of the polymers at the high drying temperature.

As determined by the procedure of Comparative Example 2, it took 2 minutes and 17 seconds on average for the dried fabric to absorb the drop of deionized water.

Example 5 The procedure of Example 4 given above was repeated with the following exceptions noted. 173% by weight, based on the dry weight of the fabric, of an aqueous solution having 100 parts per million of divalent calcium ions were added to the fabric.

As determined according to the procedure of Comparative Example 2, the tensile strength of the saturated fabric was 652 grams by 76 millimeters wide. The fabric was not dispersed in water due to the cross-linking of setting with excessive heat of the polymers at the high drying temperature.

Example 6 About 15% by weight, based on the dry weight of the nonwoven substrate, of formula 4 on both sides of the substrate were sprayed. The resulting fabric had an overall basis weight of 68 grams per square meter. The cloth was then dried and at 400 ° Farenheit for 10-15 seconds. 226% by weight, based on the dry weight of the fabric of an aqueous solution having 100 parts per million of divalent calcium ions, were added to the fabric.

As determined according to the procedure of Comparative Example 2, the tensile strength of the saturated fabric was 660 grams per 76 millimeters in width. The fabric was stable in the test solution but dispersed in water in less than 1 hour.

As determined by the procedure of comparative example 2, it took one minute and 52 seconds on average for the dried fabric to absorb the drop of deionized water.

Example 7 The procedure of Example 4 was repeated with the following exceptions noted, about 10% by weight, based on the dry weight of the non-woven substrate, of formula 4 being sprayed on both sides of the substrate. The resulting fabric had an overall average weight of 65 grams per square meter. The cloth was then dried at 400 ° Farenheit for 10-15 seconds. 204% by weight, based on the dry weight of the fabric, of an aqueous solution having 100 parts per million of divalent calcium ions were added to the fabric.

As determined according to the procedure of comparative example 2, the tensile strength of the saturated fabric was 430 grams per 76 millimeters width.

The fabric was stable to the test solution but was dispersed in water in less than one hour.

Those skilled in the art will appreciate that various substitutions, omissions, and changes and modifications may be made without departing from the spirit of the invention or from the scope of the attached clauses. Therefore, it is intended that the foregoing description be considered merely as an example of the preferred scope of the present invention and not be considered a limitation thereof.

Claims (31)

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

1. - A water-soluble binder composition for binding the fibrous material in an integrated fabric, said binder composition comprises from about 25% by weight of an unsaturated carboxylic acid / unsaturated carboxylic acid terpolymer; and from about 15% by weight, about 75% by weight of a hydrophilically crosslinkable polymer, wherein said binder composition soluble in water and soluble in an aqueous environment having a divalent ion concentration of less than about 50 parts per million and a monovalent ion concentration of less than about 0.4% by weight.

2. - The binder composition as claimed in clause 1, characterized in that it comprises from about 40% by weight, about 75% by weight of a terpolymer of unsaturated carboxylic acid / unsaturated carboxylic acid and from about 25% by weight to about 60% by weight of the hydrophilic crosslinkable polymer.

3. - A water-soluble binder composition for a fibrous binder material in an integrated fabric, said binder composition comprises from about 25% by weight to about 85% by weight of an unsaturated carboxylic acid / unsaturated carboxylic acid terpolymer; from about 5% by weight of about 35% by weight of a divalent ion inhibitor; and from about 10% by weight to about 60% by weight of the hydrophilically crosslinkable polymer, wherein said water-soluble binder composition is soluble in an aqueous environment having a divalent ion concentration of less than about 50. parts per million and a monovalent ion concentration of less than about 0.4% by weight.

4. - The binder composition as claimed in clause 3, characterized in that it comprises from about 40% by weight about 75% by weight of the terpolymer of esters of unsaturated carboxylic acid / unsaturated carboxylic acid; from about 5% by weight to about 20% by weight of the divalent ion inhibitor; and from about 10% by weight to about 50% of the polymer crosslinked in hydrophilic form.

5. - The binder composition as claimed in clauses 1 or 3, characterized in that said water-soluble binder composition is soluble in an aqueous environment having less than about 25 parts per million of a divalent ion selected from calcium or magnesium.

6. - The binder composition as claimed in clauses 1 or 3, characterized in that said terpolymer of unsaturated carboxylic acid / unsaturated carboxylic acid comprises from about 10% by weight about 90% by weight of acrylic acid and / or methacrylic acid and 90% by weight to about 10% by weight of acrylic esters and / or methacrylic esters having an alkyl group of 1 to 18 carbon atoms or a cycloalkyl group of 3 to 18 carbon atoms in which 2 to 60% mol of the repeating units are derived from acrylic acid and / or methacrylic acid are in the form of a salt.

7. - The binder composition as claimed in clauses 1 or 3, characterized in that said terpolymer of unsaturated carboxylic acid / unsaturated carboxylic acid comprises from about 20% by weight about 70% by weight of acrylic acid and / or methacrylic acid and 80% by weight to about 30% by weight of acrylic esters and / or methacrylic esters having an alkyl group of 1 to 18 carbon atoms or a cycloalkyl group of 3 to 18 carbon atoms in which 5 50% mol of the repeating units are derived from acrylic acid and / or methacrylic acid are in the form of a salt.

8. - The binder composition as claimed in clauses 1 or 3, characterized in that the unsaturated carboxylic acid acid / acid copolymer unsaturated carboxylic acid comprises from about 30% by weight to about 75% by weight of acrylic acid and / or methacrylic acid and 5% by weight to about 30% by weight of acrylic esters and / or methacrylic esters having an alkyl group of 1 to 18 carbon atoms and from 20% by weight to about 40% by weight of acrylic esters and / or methacrylic esters having an alkyl group of 2 to 4 carbon atoms of which 1 50% mole of the repeating units derived from acrylic acid are in the form of a salt.

9. - The binder composition as claimed in clause 3 characterized in that the divalent ion inhibitor is selected from the group consisting of sulfonated copolyester, polyphosphate, phosphonic acid, amino carboxylic acid, hydroxycarboxylic acid, polyamine and poly (vinyl ethylene acetate) cross-linked

10. - The binder composition as claimed in clause 9 characterized in that said divalent ion inhibitor is selected from the group consisting of Eastman AQ29D, AQ38D, AQ55D, Findley L9158 ATO, poly (vinyl ethylene acetate) with N-methylol acrylamide, sodium tripolyphosphate, nitrilotriacetic acid, citric acid, ethylenediaminetetraacetic acid, ethylene diaminetetra (methylene phosphonic acid) and porfosines.

11. - The binder composition as claimed in clauses 1 or 3, characterized in that the hydrophilic crosslinkable polymer is selected from the group consisting of poly (vinyl ethylene acetate) with substituted N-acrylamide, acrylamide, N-copolymers based on of acrylamides substituted with a crosslinkable monomer, copolyacrylates, poly (vinyl ethylene alcohol) having less than about 3% hydrolysis poly (ethylene glycol) injected into a polyolefin so that the poly (ethylene glycol) moieties bonded in cross-shaped and poly (ethylene-vinyl acetates with N-methylolacrylamide).

12. - The binder composition as claimed in clause 11 characterized in that said hydrophilic crosslinkable polymer is selected from the group consisting of N-methylolacrylamide, hydroxyethyl methacrylate copolymer with methyl methacrylate, hydroxyethyl methacrylate copolymer with methylacrylate, poly (ethylene glycol) copolymer - methacrylate (PEG-MA) with methyl methacrylate and copolymer poly (ethylene glycol) -methacrylate (PEG-MA) with methacrylate.

13. - A fibrous fabric dispersible in water comprising a fibrous substrate and the water-soluble binder as claimed in clause 1 distributed through said fibrous substrate wherein said fabric is dispersible in water in an aqueous environment having a divalent ion concentration of less than about 50 parts per million and a monovalent ion concentration of less than about 0.4% by weight.

14. - A fibrous fabric dispersible in water comprising a fibrous substrate and the water-soluble binder as claimed in clause 3 distributed through said fibrous substrate wherein said fabric is dispersible in water in an aqueous environment having a concentration of divalent ion of less than about 50 parts per million and a monovalent ion concentration of less than about 0.4% by weight.

15. - The dispersible fibrous fabric as claimed in clause 13 characterized in that said fibrous material is composed of fibers selected from the group consisting of natural and synthetic fibers.

16. - The dispersible fibrous element as claimed in clause 13, characterized in that said fibrous material will be dispersed in water in less than 90 minutes.

17. - The dispersible fibrous web as claimed in clause 13 characterized in that said fibrous material will be dispersed in water in less than about 60 minutes.

18. - The dispersible fibrous web as claimed in clause 13 characterized in that said fibrous material will be dispersed in water in less than about 30 minutes.

19. - The dispersible fibrous fabric as claimed in clauses 16, 17, or 18 characterized in that said fibrous material is dispersed in multiple pieces each having an average size of less than about 50% in relation to its predispersed size.

20. - The dispersible fibrous fabric as claimed in clause 19 characterized in that said fibrous material is dispersed in multiple pieces each having an average size of less than about 40% in relation to its predispersed size.

21. - The dispersible fibrous fabric as claimed in clause 19 characterized in that said fibrous material is dispersed in multiple pieces each having an average size of less than about 30% in relation to its predispersed size.

22. - The dispersible fibrous fabric as claimed in clauses 13 or 14 characterized in that the binder is distributed through about 80% to 100% of the fabric.

23. - The dispersible fibrous fabric as claimed in clauses 13 or 14 characterized in that said binder is distributed through about 95% to 100% of said fabric.

24. - The dispersible fibrous fabric as claimed in clauses 13 or 14, characterized in that said fabric has a wettability of less than about 15 minutes.

25. - The dispersible fibrous fabric as claimed in clauses 13 or 14, characterized in that said fabric has a wettability of less than about 5 minutes.

26. - The dispersible fibrous fabric as claimed in clauses 13 or 14, characterized in that said fabric has a wettability of less than about 1 minute.

27. - A method for making a non-woven fabric dispersible in water comprising the steps of contacting a fibrous substrate with an effective amount of a water-soluble binder as claimed in clause 1 as to bind a substantial amount of fibers in said substrate and drying the fibrous substrate.

28. - A method for making a non-woven fabric dispersible in water comprising the steps of contacting a fibrous substrate with an effective amount of a water-soluble binder as claimed in clause 3 as to bind a substantial amount of fibers in said substrate and drying the fibrous substrate.

29. - The method as claimed in clauses 27 or 28 characterized in that about 1% by weight to about 50% by weight of said binder is distributed on said fabric.

30. - The method as claimed in clause 29 characterized in that about 5% by weight to about 30% by weight of said binder is distributed on said fabric.

31. - The method as claimed in clause 29 characterized in that about 8% by weight to about 25% by weight of said binder is distributed on said fabric. E S U M E N A water-soluble polymer binder for binding a fibrous substrate comprising from about 25% by weight to about 85% by weight of an unsaturated carboxylic acid / unsaturated carboxylic acid ester terpolymer, of from about 5% by weight to about 35% by weight of a divalent ion inhibitor, and from about 10% by weight to about 60% by weight of a crosslinkable hydrophilic polymer. In a preferred mode the invention the hydrophilic crosslinkable polymer functions essentially as a divalent ion inhibitor and promotes the hydrophilicity of the treated fabric by eliminating the requirement of a separate divalent ion inhibitor. The soluble binder composition in an aqueous environment having a divalent ion concentration of less than about 50 parts per million and a monovalent ion concentration of less than 0.4% by weight. A fibrous fabric dispersible in water having an effective amount of the binder distributed on the fibrous substrate and a method for making a fibrous fabric dispersible in water is also disclosed.