KR830001106B1 - Preparation of Composite Sheet Material - Google Patents

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Description

Preparation of Composite Sheet Material

The present invention relates to a method for producing a composite sheet material from a polyurethane polymer and a porous sheet material. Properly finished natural leather is used for many purposes because of its durability and beautiful properties. As leather is scarce and the cost of making processed leather required for a particular application increases, it is desirable to replace the place where the leather product was used with a synthetic material instead, considering economic circumstances. These synthetics have been proposed for use in shoe uppers, upholstery, clothing, baggage making, bookbinding, and the like. These different uses require a variety of physical, chemical and aesthetic properties, so different processes using different materials have to be obtained which are comparable to natural leather. In most cases, these synthetic materials are the same even if they are easily distinguished from natural leather.

One method of making a synthetic substitute for leather includes impregnating or coating a porous material, such as polyurethane, vinyl or similar cloth.

Polyurethanes have been widely used as constituents necessary for coating or impregnation, since they are very likely to change in their chemical and physical properties, especially their flexibility and chemical resistance.

The purpose of producing such synthetics as leather substitutes is to (1) sheets which have a leather-like effect or are particularly suitable for the use of furniture; (2) sheets of constant width, usually used in the textile industry (not the same as natural products that maintain the actual weight and area lost during the cutting and finishing process); (3) the flexibility of the end use, for example, to apply certain chemical treatments under a variety of different exposure conditions so that its properties can be maintained permanently; (4) Most importantly, provide products with strength, hand, drape and softness comparable to natural leather.

In addition, when intended for use in oral uppers, the impregnated fabric sheet material has a leathery appearance, undesired properties of shining to the back of the fabric, water vapor well penetrating into the uncoated interior of the upper, and It should be characterized by fine wrinkle rupture (least grainy crease) such as leather. Known in the leather and upholstery industry, "skin-like crease rupture" is evident by the nature of folded or crinkled leather. The folds of this leather are characterized by a flat, curved appearance with several delicate folds in the crimped area of the crease. This is in contrast to the sharp creases or rough wrinkles that occur when paper or film is folded. This kind of undesirable appearance is known as "pin wrinkling."

When used for another purpose, it is desirable to provide a reinforced fabric, which can be sanded or fluffed to create a beautiful surface and can be used as an upholstery material without additional coating. Important properties for upholstery include strength, reduced Bias elongation, and well-woven fabrics with improved appearance, such as softness, drape, compliance, and no backlit substrate. Bias elongation is important not only for upholstery, but also for shoe uppers, and reflects the desired resistance required to stretch the fabric under more stress in the end use; Overstretching the fabric will cause pin wrinkles and brighten the backside.

It is desirable to provide coated fabrics of increased strength and good appearance when used in another application. Such coated fabrics enhance chemical and physical properties to represent actual fabric types.

Polyurethane polymers coated or impregnated for textiles have long been known to provide some of the aforementioned properties. For example, polyurethanes can be produced that are very resistant to solvents and abrasion, are dry washable and provide significant durability to coated fabrics. The basic chemistry of polyurethanes involves the reaction between isocyanate groups and molecules containing a number of active hydrogens, such as polyols or polyamines, and, depending on the choice of intermediates, has considerable consumer and physical properties and Given the variability, a desired balance is obtained for the processing needs and the requirements required for performing the end use.

There are many ways to apply polyurethane solutions, or other post-treatment liquid polymers, to porous substrates well known in the art. Papers in the Journal of Coated Fabrics, Vol. 7 (July 1977), pp.43-57, include commercial coatings such as reverse roll coating, pan fed coater, and gravure printing. Several systems are described. Brushing and spraying can also be used to cover polyurethane with a porous substrate. After impregnation or coating of the porous substrate, these polyurethane solutions are dried or treated by heating air, infrared irradiation or the like.

A feature of this process is that the polymer and film-like layers are precipitated, which tends to produce an undesired sharp wrinkled coated fabric rather than a fine crease rupture such as leather.

Another method of compounding a polyurethane solution with a porous substrate is described in US Pat. No. 3,208,875. In short, this method applies a polymer solution in an organic solvent to a substrate (such as a needle punched polyester batt), and then applies a layer of the polymer to the organic solvent of the polymer and the nonsolvent of the polymer. Dipping into a mixture of; That is, at least partially mixed with the solvent until the layer of polymer solidifies within the more tightly bound micropores of the cellular structure. This solvent is removed from the coating layer with the non-solvent to form a solvent free microporous layer. Although this method imparts good properties to fabrics impregnated with polyurethane, it has the disadvantages of organic solvent systems, especially when using high-performance polyurethanes, which require relatively toxic and high boiling solvents.

Polyurethane dispersions containing organic media have been proposed and used in coated fabrics. U.S. Patent No. 3,100,7 describes a dispersion prepared by adding a bi-solvent to a polyurethane solution. The dispersion applied to the substrate condenses by adding a non-solvent. Although this approach has been used successfully occasionally, it has two important limitations: (1) The medium of the dispersion is organic in nature, so a relatively small amount of non-solvent and preferably water is needed to form the dispersion; (2) The useful range of the non-solvent added is narrow, and it is difficult to obtain a reproducible result.

Although useful products based on polyurethane solutions or dispersions containing organic mediators are provided, methods using a polyurethane structure that is dilutable in water are much preferred to overcome the obstacles of previous methods.

In accordance with the present invention, a method is provided for preparing a polyurethane polymer impregnated with a porous substrate, wherein water is a vehicle for the polyurethane polymer structure.

In addition, the foregoing disadvantages described with the prior art system are overcome according to the present invention to provide a product such as leather suitable for various applications in one process.

Also provided is a method of producing a coated fabric according to the present invention.

Further side advantages of the aqueous system are provided by the present invention.

It is recognized in the art that polyurethanes useful in the practice of the present invention can be ionically dispersed in water. This dispersion is different from the emulsified isocyanate interpolymer as described in US Pat. No. 2,968,575 and is dispersed in water by detergent under the action of formulated strong shear forces. Emulsified polyurethane is in the form of an emulsion by using a detergent and usually these detergents are left in the membrane of the dried emulsion has the disadvantage that the physical and chemical properties of the final product is significantly reduced. In addition, insufficient shear forces result in unstable products and these products require high shear forces that cannot be calculated with conventional reaction vessels. A preferred system for the preparation of ionic aqueous polyurethane dispersions is the preparation of polymers having free acid groups, ie carboxylic acid groups covalently bonded to the backbone structure of the polymer, which neutralize these carboxyl groups with amines, ie water-soluble mono-amines. Water dilution. Since isocyanates, which are essential components in any polyurethane system, are generally reactive with carboxyl groups, care must be taken when selecting compounds having such carboxyl groups.

However, as described in US Pat. No. 3,412,054, carboxylic acids substituted with 2,2-hydroxymethyl can be reacted with organopolyisocyanates without significant reaction between acid and isocyanate, which is adjacent to the alkyl group. This is because the carboxyl group causes steric hindrance.

This treatment method neutralizes the carboxyl groups with tertiary mono-amines to supply the internal quaternary ammonium salts, making the polymer containing the desired carboxyl groups and having water dilution. Suitable carboxylic acids, preferably those which cause steric hindrance, are well known and readily available. For example, these carboxylic acids can be prepared from aldehydes containing at least two hydrogen atoms in the α position, which react with two equivalents of formaldehyde in the presence of a base to form 2,2-hydroxymethyl aldehyde. The aldehydes are then oxidized to acids using methods known to those skilled in the process. The structural formula of these acids is as follows.

R in the formula represents hydrogen or an alkyl group up to C ₂₀ , in particular an alkyl group up to C ₈ , and more preferred acids are 2, 2-di- (hydroxymethyl) propionic acid.

Polymers having pendant carboxyl groups are characterized as anionic polyurethane polymers.

In addition, another method of making water dilution according to the present invention is to use a cationic polyurethane having a pendant amino group. Such cationic polyurethanes are described in particular in Example 18 of US Pat. No. 4,066,591. In this invention, it is preferable to use anionic polyurethane.

Polyurethanes useful in the practice of the present invention include the reaction of di- or polyisocyanates with compounds containing a number of active hydrogens suitable for the production of polyurethanes. Such diisocyanate and active hydrogen compounds are described in more detail in US Pat. Nos. 3,412,034 and 4,046,729. In addition, methods for producing such polyurethanes are well known as exemplified by the above patents.

According to the invention aromatic, aliphatic and cycloaliphatic diisocyanates or mixtures thereof can be used to form the polymer.

Such diisocyanates include tolylene-2, 4-diisocyanate, tolylene-2, 6-diisocyanate, meta-phenylenediisocyanate, biphenylene-4, and 4'-diisocyanate. Acid salts, methylene-bis (4-phenylisocyanate), 4-chloro-1, 3-phenylenediisocyanate, naphthylene-1, 5-diisocyanate, tetramethylene-1, 4-diisocyanate Acid salts, hexamethylene-1, 6-diisocyanate, decamethylene-1, 10-diisocyanate, cyclohexylene-1, 4-diisocyanate, methylene-bis (4-cyclohexyl isocyanate ), Tetrahydronaphthylene diisocyanate, isophorone diisocyanate, and the like. Preferably arylene and cycloaliphatic diisocyanates are most usefully used in the practice of the present invention. Characteristically, arylene diisocyanate includes all diisocyanate salts in which isocyanate groups are attached to the aromatic ring. The best isocyanates are the 2, 4 and 2, 6 isomers of tolylene diisocyanates or mixtures thereof, which are good because they are readily available and active. Furthermore, the cycloaliphatic diisocyanates most advantageously used in the practice of the present invention are 4, 4'-methylene-bis (cyclohexyl isocyanate) and isophorone diisocyanate.

The choice of aromatic or aliphatic diisocyanates depends on the end use of the particular material. As is well known in the art, aromatic isocyanates can be used when the final product is not overexposed to the ultraviolet rays that yellow such polymer compositions. However, aliphatic diisocyanates have less tendency to yellow when exposed to ultraviolet radiation, and thus may be more advantageous for external use.

While this principle is a general basis for selecting the particular isocyanate to be used, aromatic diisocyanates can be stabilized again with known UV stabilizers to enhance the final properties of the polyurethanes, which are impregnated with the sheet material. In addition, it is possible to add levels of antioxidants known in the art, which are necessary to enhance the properties of the final product. Typical antioxidants include thioethers, 4, 4'-butylidinebis-meth-cresol and 2, Phenolic antioxidants such as 6-di tert-butyl-para-cresol. Isocyanates react with many active hydrogen compounds such as diols, diamines or triols. In the case of diols or triols they are typically polyols of polyalkylene ethers or polyesters. Polyalkylene ether polyols suitable for the production of polyurethanes are polymerizable materials containing active hydrogen, the most useful polyglycols having a molecular weight of 50-10000 and most preferably 40-7000 in the present invention.

Poly ether polyols increase flexibility proportionally with increasing molecular weight.

Examples of polyether polyols include, but are not limited to, polyethylene ether glycol, polypropylene ether glycol polytetramethylene ether glycol, polyhexamethylene ether glycol, polyoctamethylene ether glycol, polydecamethylene ether glycol, polydodecamethylene ether glycol and their Mixtures and the like. Polyglycols containing several different radicals in the molecular chain, for example the compound HO (CH ₂ OC ₂ H ₄ O) _n H (where n is an integer greater than 1) may also be used.

The polyols may also be polyesters terminated with hydroxy groups or with hydroxy groups bound, which may be used in place of or in combination with or in combination with polyalkylene ether glycols. These polyesters are those formed by reacting an acid, ester or acid halide with glycol. Suitable glycols include polymethylene glycols such as ethylene, propylene, tetramethylene or decamethylene glycol, substituted methylene glycols such as 2, 2-dimethyl 1 and 3-propanediol, cyclic glycols such as cyclohexanediol and aromatics Glycols and the like. In general, when flexibility is required, it is preferable to use aliphatic glycols. These glycols are reacted with aliphatic, cycloaliphatic, aromatic dicarboxylic acids or lower alkyl esters, or esters forming derivatives to form relatively low molecular weight polymers, i.e., melting points of up to 70 degrees Celsius and molecular weights in polyalkylene ether glycols. To produce the polymer as indicated. Acids for making these polyesters include maleic acid phthalic acid, succinic acid, adipic acid, suberic acid, terephthalic acid, hexahydrophthalic acid and derivatives in which these acids are substituted with alkyl and halogen. In addition polycaprolactone terminated with hydroxy groups can also be used. As used herein, "ionic dispersant" refers to a base that can shape salts with acids or solubilizing agents that can be dissolved and ionized in water. These "ionic dispersants" are amines, preferably water-soluble amines such as triethylamine, tripropylamine, N-ethylpiperidine, and as the acid, preferably water-soluble acids such as acetic acid, propionic acid, lactic acid, and the like. Acids or amines are selected depending on the solubilizing group that depends on the chain of the polymer.

The desired elastomers generally require about 25 to 80 weight percent long chain polyols (ie, 700 to 2000 equivalent weight) in the polymer. The elongation and elasticity of the chain varies greatly from product to product, depending on the desired properties of the final product. In preparing polyurethanes useful in the practice of the present invention, polyols and molar diisocyanates are reacted to form polymers having isocyanate groups at their ends. Appropriate reaction conditions, reaction times, and reaction temperatures may vary within the relationship of the particular isocyanate and polyol used, but those skilled in the art are fully aware of these changes. The skilled artisan knows that the reactivity of the components requires a balance of reaction rates, with undesirable side reactions leading to a decrease in color or molecular weight. The reaction is typically stirred for 1-4 hours at about 50-120 degrees Celsius. In order to provide a pendant (side-chain bonded) carboxyl group, a polymer having an isocyanate group bound to the terminal is reacted with an acid lacking one mole of dihydroxy group for 1-4 hours at 50-120 degrees Celsius, so that the isocyanate group is terminated. Make a combined prepolymer. The acid is preferably added, for example, as N methyl-1, 2-pyrrolidone or N-N-dimethylformamide solution.

The solvent for the acid is in principle not to exceed about 5% of the total amount in order to minimize the concentration of the organic solvent in the polyurethane composition.

The dihydroxy acid is reacted in the polymer chain, the pendant carboxyl group is neutralized with an amine for about 20 minutes at about 58 to 75 degrees Celsius, and water is added while stirring to extend and disperse the chain. A water soluble diamine may be added to the water as an additional chain additive. This elongation of the chain involves the reaction of water with the remaining isocyanate groups to form urea groups, and the polymerization of the polymerizable material as a result of reacting all isocyanate groups by stoichiometric addition of water. do.

It is noteworthy that the polyurethane of the present invention is originally thermoplastic, ie it cannot be cured again after production without the addition of a curing agent from the outside. When making a synthetic sheet material, it is preferable not to add such hardening | curing agent as much as possible.

Sufficient water is needed to disperse the polyurethane at a solid weight of about 10-40% concentration and the dispersion viscosity in the range of 10-1000 centipoise.

Viscosity can be adjusted according to the specific impregnation desired and the composition of the particular dispersion indicated by the properties of the final product. It is noteworthy that no emulsifier or thickener is required to stabilize this dispersion.

Depending on the end product's use, those skilled in the art know how to modify the primary polyurethane dispersion by adding colorants, compatible vinyl polymer dispersions, ultraviolet filterable compounds, stabilizers for oxidation, and the like. .

Characterization of the dispersions prepared according to the invention is made by measuring the non-volatile content and particle size, measuring the viscosity and strain deformation of the cast film pieces. The useful operating concentration limit for this dispersion is very wide, about 5-50%. The lower limit is set by the inability to remove large amounts of water from the impregnated porous substrate and the tendency to illuminate the undesired back side of the substrate. The upper limit of solids concentration is the viscosity of an excessive dispersion that prevents rapid and complete penetration of the desired degree for applications such as furniture requiring flexibility or susceptibility, and the undesirable fabric stiffness that results from substantially filling the entire substrate with polymer. Is characterized by.

Preferred ranges of concentration are about 10-40% of the weight of the solid. Dispersion viscosity is generally in the range of 10-1000 centipoise and, as far as the viscosity of the same polymer is concerned at the same solids level in the polymer solution with organic solvents, the branching diagram helps the rapid and complete penetration of the aqueous acid solution followed by the penetration of the coagulant. Help Polyurethane useful solutions, on the other hand, generally have a viscosity of thousands of centipoise and reach up to 50,000 centipoise at concentrations of 20-30%. In one particular application, if one wants to saturate the surface of the porous substrate with the aqueous dispersion of the present invention, a water soluble thickener such as carboxymethyl cellulose can be used to increase the viscosity. However, this concentration can also be accomplished by increasing the solid concentration.

If the stability is to be easily measured, the particle size may be measured by light scattering. Useful dispersions without settling have particle diameters less than 1 micron. Porous substrates useful in the practice of the present invention include wovens, knits, felts, and nonwovens such as spun-attached sheets, quilted batts, and waterleaves. Fibers of suitable substrates include natural fibers, especially cotton (pure cotton and mixed cotton with synthetic fibers such as polyester or nylon) and, although not so good, wool and synthetics such as polyester, nylon, acrylic modacryl and rayon There is a fiber. The fibers may be straight, corrugated, continuous filaments or staples (fibres cut to a suitable length for spinning) or may be of paper length. The choice of fiber, substrate form and structure, and weight per unit area is, of course, made by considerations commonly recognized in the coating, end-use requirements, and other textile and textile industries, but the choice of the composition is specific. Depends on the use

During the process of the present invention, the substrate is impregnated into the polyurethane within the range of about 5 to 70%, preferably 15 to 50% of the total composition weight. Therefore, the properties of the porous sheet of the substrate have a strong influence on the properties of the composite fabric. Measurements of whether a finished sheet has properties suitable for shoe or furniture applications include tensile strength, tear strength and bias resistance. Unlike the impregnated product produced by the present invention, the film-like impregnation generally has a large wrinkle due to inferior tensile strength and tear strength. It is important to maintain a uniform appearance and to maintain this appearance depending on the end use of each item manufactured. For example, suede-type outerwear is desired to maintain color and soft texture in time and to withstand the use of the outerwear for many years through washing and grooming at home.

Methods of preparing satisfactory substrates useful in the method of the present invention are known to those skilled in the art of textiles. Preferred substrates are fabrics of approximately 8 oz / square yards woven from cotton staples or a blend of man-made fibers and cotton.

This choice helps to ensure a highly durable substrate with reproducibility and predictability. The sequence of such operations is (1) weaving the fabric by staple spinning; (2) dyeing the fabric (after removing any adhesives that may be helpful in the manufacture and weaving of the yarn); (3) brushing or sanding to lift the ends of the fibers from the fabric body to cause fluff; (4) For the next impregnation, the fabric is precisely cut to equal thickness and width. Subsequent to impregnation and condensation with the polyurethane dispersion, the finishing step usually involves buffing. Buffing creates a suede surface, in which case the fibers facing the surface of the substrate are preferably beautiful, and buffing can also be used to ensure uniformity of thickness to control the inversion coating of the additional polyurethane.

Because the substrate is porous, the aqueous polyurethane dispersion passes through the pores of the substrate at a rate controlled by the viscosity of the aqueous system and the hydrophilic properties of the particular substrate used. Therefore, any of the methods used in the waterproof textile industry, as described above, are suitable for impregnating aqueous dispersions with porous substrates.

Condensation is completed by contacting the saturated substrate with an aqueous solution of an ionic medium designed to ionically dissolve soluble ions. In theory, in the case of anionic dissolved polyurethanes (though not intended to be bound by this theory), the amines that neutralize the polyurethanes containing carboxyl groups are replaced by hydrogen ions that return to anionic pendant carboxyl ions. To convert the polyurethane polymer to its original "non-dilutable" state. This causes coagulation of the polymer in the substrate structure.

In the case of anionic polymers, an aqueous acetic acid solution at a concentration of about 0.5-5% is suitable as an ionic coagulant for the anionic dispersion. It is also preferred over stronger acids because of its relatively easy handling, low corrosiveness, and ease of treatment. Other acids that are substantially water soluble may be used at the same concentration. The condensation is very fast and indeed very fast so that the polymer is substantially entirely in the substrate so that there is no loss of polymer by migration into the ionic solution. "Salt", which neutralizes the dispersion with the addition of neutral salts, is feasible but not desirable because it requires a large amount of salt, requires about 10 times the concentration of the acid, and involves contamination of the product.

Since the polymers used to practice the invention are numerous and varied, it may be helpful to follow the following methods to determine the condensation conditions for a particular polymer:

(1) For example, make an aqueous continuous dilution solution of selected ionic coagulant, such as acetic acid. It has specific concentrations of 5%, 2.5%, 1.25%, 0.312% and 0.156% and this range is about 30 times the acid concentration but thus generally encompasses the practical range of ionic coagulants. (2) The coagulant solution is stirred at a stirring speed of about 300 rpm in a container of about 100 cc. (3) The aqueous polyurethane dispersion is added dropwise into the stirred agglomerate at a rate of about 20 drops per minute. It will be appreciated that in the high concentration range the dispersion condenses into small droplets of distinct shape to form the outer surface of the condensed polyurethane, and in very low concentrations a milky dispersion is formed which is not suitable for the practice of the present invention.

There is considerable margin in choosing a functional ionic coagulant concentration so the lower limit is about 0.2% acid solution.

The choice of specific concentration is, of course, determined by the actual requirements for the recycling of the coagulant bath and the economic treatment of the remainder of the acid.

After the condensation process, the retained aqueous phase is removed by conventional means. For example, the sheet can be passed through a compression roller, rinsed with water and dried by hot air or infrared radiation. In a representative method, the porous substrate is saturated with a polyurethane dispersion in a suitable container and the excess is removed with a compression roller. The saturated substrate is then immersed in a suitable capacity of the ionic coagulant, and the remaining liquid, mainly composed of the ionic coagulant and the dissolved ionic salt, is removed by a compression roller. The impregnated substrate is rinsed and air dried or dried by hot air or infrared radiation.

This method can be applied to all polyurethanes that can be diluted with water, but the purpose of this product is to provide the appearance, strength, comfort and suspension suited to the essential requirements of shoes, upholstery and leather garments for end use.

It is another object of the present invention to provide a coated fabric having a feeling of suspension with increased strength and washability. In this case, generally polyurethanes need to contain relatively low rates. Preferred secant modulus at 100% elongation is 20-100 psi and useful range is about 10-1500 psi. This coefficient is customarily calculated from stress-stress strain curves obtained from molded film pieces and dried polymer dispersions. Cut elongation, which means acceptable elastic extensibility, is calculated by the stress-stress strain curve, but it must be in the range of 300-800%, preferably in the range of 500% or more, and twice the length without stress. When stretched, it must retain elastic recovery to within 30% of its original length. After manufacturing and drying, the sheets can be rubbed gently using the leather industry's conventional methods to produce an attractive suede effect and, if desired, the best finish for the shoe upper. Coated this sheet and to devices already in use in the leather and clothing textiles industry (see, for example, transfer coating lines in the table in Coated Fabrics, Vol. 7 (July 1977), p. 43). It can also be bonded to the leaf structure consisting of a foam and cloth.

The product by this condensation method is different from the product made by the method of precipitating and evaporating the polymer in an aqueous dispersion. This evaporation method tends to produce a shiny film-like surface rather than an attractive surface with a smooth luster and tends to be broken by bending or subject to other performance and cosmetic defects. Preferred cleavability, permeability, suspension and flexibility are believed to be related to the dense polymer structure versus cell structure produced by the drying process.

The difference in the microscopic structure of the polyurethane precipitated by the two previous methods was demonstrated by adding the dispersion to the two glass slides to produce the film in the following manner. The methods are (1) a method of condensation by dipping a slide in an ionic coagulant, and (2) a method of drying the dispersion.

The product in (1) is white and opaque, which is the result of light scattering by the good cell groups produced and can be seen by microscopic examination. The product of (2) is generally clear and spaceless film, but there is something blurry here. Light scattering of the condensed polyurethane cells is evident from the fact that they become white simultaneously with addition of a coagulant during dispersion of the dispersion in the substrate.

Of course, the structure of these cells should be durable in use, including washing with solvents, and should minimize appearance or performance changes over time. This durability depends primarily on the selection of a suitable polymer composition that can be made by principles well known in the polymerization art. In order to describe the present invention in more detail, examples are provided, but the present invention is not limited thereto. Polyurethane polymers are made from the following components.

Diisocyanate is reacted with an active hydrogen compound under an inert atmosphere until substantially all of the active hydrogens react to leave only intermediates having N = C = 0 groups at the ends. The dissolution aid compound is reacted with this intermediate to bind the dissolution aid into the polymer chain. The polyurethane polymer is neutralized with an ionic dispersant and then the polyurethane polymer is added to a significant amount of water, with the chain stretching the polyurethane polymer. The solid concentration is then adjusted to the desired level by adding more water.

As mentioned above, one bath containing a polyurethane dispersion is prepared at normal temperature. Porous substrates are impregnated in this bath and the excess polyurethane aqueous dispersion is squeezed out. The substrate impregnated with the dispersion is immersed in a bath containing a stoichiometric or one equivalent excess of coagulant to condense the polyurethane from the dispersed phase. The substrate impregnated with the dispersion is washed with water to remove the remaining dispersant and coagulant, and excess water is squeezed or removed in a similar manner and the impregnated is dried. If necessary, physical treatment or coating may be continued depending on the end use.

Example 1

Polymers containing acids, but not isocyanates, dispersed in water, were prepared using the following ingredients:

This tolylene diisocyanate was combined with triol while stirring at 10-30 degrees Celsius under an inert atmosphere. Triol and isocyanate were allowed to react for 2 hours at a constant stirring speed and component mixing rate, and the temperature was maintained not to exceed 80 degrees Celsius. An acid solution in pyrrolidone was added to the compound of diisocyanate / triol and again the temperature was kept below 80 degrees Celsius for 30-90 minutes. Morpholine was added and the reaction was held for 20 minutes to neutralize the dimer, with the temperature of the mixture maintained in the range of 55-75 degrees Celsius. The polyurethane was added to water and then stirred until the bubble-induced bubble-induced expansion in water stopped, resulting in chain extension and dispersion of the neutralized polymer in water. This reaction typically took 1-4 hours and the final temperature was 40-60 degrees Celsius. Water was added to the finished dispersion to adjust the nonvolatile content to 30%. The viscosity of this 30% dispersion was 350 centipoise as measured by a Brookfield RVT viscometer. The average particle size (by Spectronic 20 (Bausch & Lomb) apparatus) measured from the scattering of light was about 0.7 microns. The properties measured using Instron Model 1130 on films formed from this dispersion are as follows:

100% Modulus 75psi

(Stress required to double sample length) Tensile strength 370 psi

Elongation 800%

Recovery rate (from thing extended at twice the original length) 80%

Example 2

A polymer containing acid but not diisocyanate, dispersed in water, was prepared from the following components:

을 섭씨 50-90의 불활성 분위기 하에서 교반시키면서 PCP-0240과 화합시켰다. 이 반응시간은 2시간 이었고 온도는 섭씨 90도를 넘지 않도록 유지하였다. 피롤리돈 중의 산 용액을 산토화이트

과 함께 디이소시안산염/디올 화합물에 첨가하였다. 디부틸주석 디라우르산염을 가하고 2-3시간동안 온도를 섭씨 80도를 넘지 않게 유지하였다. N-에틸 모르폴린을 가하여 이 중합체를 중화시키는데 이 반응은 섭씨 55-75도의 온도를 유지하면서 30분동안 계속되었다. 이 중화시킨 중합체를 빠른 속도로 교반시켜 사슬을 신장시키고 물에 분산시켰다. 교반은 거품이 사라질 때까지 계속되었으며 첨가및 교반에 소요된 총 시간은 5시간이었고 최종 온도는 섭씨 55∼75도였다.Highland W

Was combined with PCP-0240 with stirring under an inert atmosphere of 50-90 degrees Celsius. The reaction time was 2 hours and the temperature was maintained not to exceed 90 degrees Celsius. Santo white acid solution in pyrrolidone

With diisocyanate / diol compound. Dibutyltin dilaurate was added and maintained at a temperature no higher than 80 degrees Celsius for 2-3 hours. N-ethyl morpholine was added to neutralize the polymer and the reaction continued for 30 minutes while maintaining a temperature of 55-75 degrees Celsius. The neutralized polymer was stirred at high speed to stretch the chain and disperse in water. Stirring continued until foam disappeared and the total time for addition and stirring was 5 hours and the final temperature was 55-75 degrees Celsius.

Water was added to the finished dispersion to adjust the nonvolatile content to 40%. The viscosity of the dispersion and the particle size measured by the method in Example 1 were 70 centipoise and 0.2 micron, respectively. The properties measured for the dried film molded from this dispersion are as follows:

100% Modulus 850 psi Elongation 350%

Tensile Strength 1600psi Recovery 55%

Example 3

The dispersion of Example 1 was coagulated and combined with cotton fabric. A commercially dyed cotton fabric, 60 × 80 males and 8 ounces / square yards, was fluffed and sheared. A square piece of test piece was cut for experimental use and then immersed in the dispersion to saturate the test pieces and pass between nips to remove excess liquid. The sheets were then immersed in 5% aqueous acetic acid solution for 5 minutes, washed for 5 minutes with purified water, partially dried by passing through a nip roller, and then oven dried for 5 minutes at a temperature of 70 degrees Celsius. The dried sheet specimens were sanded to make the same thickness and tested for oral use of the main characteristics.

Example 4

The dispersion described in Example 2 was coagulated and blended with cotton fabric as follows. A commercially dyed cotton fabric weighing approximately 8 ounces per square yard and 60 × 80 water was fluffed and sheared. Approximately one square foot of test pieces were cut for laboratory processing. The test piece was immersed in the dispersion to saturate and then the saturated sheets were passed between nip rollers to remove excess liquid. The sheets were then immersed in 5% aqueous acetic acid solution for 5 minutes, washed for 5 minutes with clean water, partially dried using a nip roller and again for 5 minutes in an air oven at 80 degrees Celsius. The finished sheet was stiff and had plate-like properties similar to cellulose-based cardboard, but was excellent in resistance to abrasion and shoe scratches, and was effective in bookbinding.

Example 5

A polymer containing amine but not isocyanate, dispersed in water, was prepared using the following ingredients:

과 메틸에틸케톤을 섭씨 15-35도에서 교반하며 화합시켰다. 불활성 분위기 하에서 CD-230을 교반하면서 가하고 온도는 섭씨 50도를 넘지 않도록 유지하였다. 그런 다음 여기에 PPG-1025와 메틸디에탄올아민을 계속해서 교반시키면서 가하였다.Hailen W

And methyl ethyl ketone were combined with stirring at 15-35 degrees Celsius. CD-230 was added with stirring under an inert atmosphere and the temperature was maintained not to exceed 50 degrees Celsius. Then, PPG-1025 and methyldiethanolamine were added thereto with continuous stirring.

Dibutyltin dilaurate was added and the temperature was maintained at 75-85 degrees Celsius for 2 hours. Water and 1% HCl solution were mixed and then the polymer was dispersed in the final solution with rapid stirring. Stirring continued until the froth disappeared and the total time for addition and stirring was 6 hours and the final temperature was 55-75 degrees Celsius.

Water was added to the finished dispersion, followed by filtration to adjust the nonvolatile content to 24%. The viscosity of the dispersion, measured by Brookfield RTV Viscometer, was 15 centipoise and the pH was 5.1.

The average particle size (by Bausch & Lomb Spectroric 20) measured from light scattering was 0.1 micron.

The properties measured using Instron Model 1130 on films formed from this dispersion are as follows:

100% modulus (stress required to double sample length) 1300 psi

Tensile strength 1950psi

Elongation 220%

25% of recovery rates (from extending twice the original length)

Example 6

The dispersion of Example 5 was coagulated and combined with cotton fabric. A commercially dyed cotton fabric, 60 × 80 males and 8 oz / square yards in weight, was sheared with a fluff.

Specimens of approximately 1 square foot in area were cut for use in laboratory processing. The specimen was immersed in the dispersion to saturate and passed through the nip roller to remove excess dispersion. This saturated sheet was immersed in 10% aqueous NaOH solution for 5 minutes, washed with clean water for 5 minutes, then partially dried using a nip roller and again dried in an air oven at 80 degrees Celsius for 5 minutes. The resulting sheet was stiff and cellulose-like cardboard-like, which was useful for bookbinding.

As it may be well known to those skilled in the art, the present invention can use an aqueous acid solution of an anionic or cationic polyurethane polymer, and various fabrics can be used as the porous substrate.

Although the present invention has been described with respect to particular materials and prepared according to certain methods, the present invention is limited only within the scope of the claims herein.

Claims (1)

A method for producing a composite sheet material as described herein above, wherein the polyurethane polymer has a solubilizing ionic group that reacts with the ionic dispersant and is covalently bonded to the polymer chain, but which is substantially free of unreacted N = C = 0 groups. Impregnated at least a portion of the porous sheet material with an aqueous ionic dispersion of, and ionically condensed the polyurethane polymer from the dispersion impregnated with the porous sheet material, and then the impregnation (substrate impregnated with the dispersion) was dried. Method of Making a Composite Sheet Material.