JP2005126848A - Method for producing porous structure, artificial leather and synthetic leather - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for producing a porous structure, by which a porous structure that is obtained by using an aqueous polyurethane water dispersion without using an organic solvent and has performances comparable with those of a porous structure obtained by using a wet solvent-based polyurethane is obtained and to obtain artificial leather and synthetic leather produced by the method. <P>SOLUTION: The method for producing the porous structure comprises providing a substrate with a mixed solution containing (A) an aqueous polyurethane water dispersion, (B) a water dispersion of a urethane prepolymer-terminated isocyanate block containing 10-40 mass% of a constituent unit composed of a polyoxyethylene having 100-2,000 average molecular weight in a molecular skeleton and (C) a tertiary amine and drying the substrate by dry heat or drying after heating by wet heat. The artificial leather and the synthetic leather are obtained by the method. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a method for producing a porous structure, artificial leather, and synthetic leather. More specifically, the present invention can provide a porous structure having performance comparable to that of a porous structure produced using a wet solvent-based polyurethane, using an aqueous polyurethane without using an organic solvent. The present invention relates to a method for producing a porous structure, and an artificial leather and a synthetic leather obtained by the method.

Conventionally, various leather adjustment products such as artificial leather, synthetic leather, and artificial leather have been manufactured as substitutes for natural leather. Many products have porous structures formed inside or on the top of substrates such as woven fabrics, knitted fabrics and nonwoven fabrics in order to bring the texture and breathability close to those of natural leather. As a method for producing these porous structures, a polymer such as elastic polyurethane is dissolved in a water-soluble organic solvent such as dimethylformamide, and further, a base material is impregnated or coated with a solution to which various additives are added. A wet coagulation method is commonly used in which a polymer is solidified by treatment with a solvent miscible with the water-soluble organic solvent without dissolving the polymer, and then the solvent is removed and dried. However, in this wet coagulation method, many water-soluble organic solvents used have strong flammability and strong toxicity, and thus there are problems such as fire risk, deterioration of work environment, and environmental pollution. In addition, since the manufactured leather preparation has a concern that a water-soluble organic solvent remains, a large amount of labor and cost are required to prevent these.
In order to solve these problems, a method for producing an aqueous porous structure having a low environmental load has been studied. For example, bubbles are mixed in an aqueous polyurethane aqueous dispersion using a foaming agent. Method, a method in which an aqueous polyurethane aqueous dispersion is heated and coagulated in the presence of a water-soluble polymer such as starch to form a crosslinked structure, and then washed with water to remove the water-soluble polymer to obtain a porous structure, There are methods such as obtaining a porous structure using an inorganic salt or an inorganic mineral in an aqueous polyurethane water dispersion.
In addition, as a method for producing a porous material suitable for artificial leather without using an organic solvent, a water-soluble highly crystalline natural product is added to a water-based urethane resin emulsion, and the water-soluble highly crystalline natural product is coagulated by wet heat. There has been proposed a method in which a cross-linking agent and an additive that are insoluble in water in the process are used in combination, and a portion where moisture exists after drying is used as a continuous foam porous body (Patent Document 1). Furthermore, as a method for producing a porous structure having a structure close to natural leather without using a water-soluble organic solvent having strong flammability and toxicity, an aqueous thermoplastic binder solution and a urethane prepolymer-terminated isocyanate blocked product are used. In addition to the above, there has been proposed a method in which a mixed liquid containing at least one of an inorganic compound, a water-soluble organic polymer, and a high cloud point surfactant is applied to a substrate, heated with moist heat, and dried (Patent Document 2). ). However, it has been difficult to stably obtain a porous structure by any method.
JP 2001-172882 A (2nd page) JP 2002-249987 A (page 2-3)

  INDUSTRIAL APPLICABILITY According to the present invention, a porous structure having performance comparable to that of a porous structure produced using a wet solvent-based polyurethane can be obtained using an aqueous polyurethane aqueous dispersion without using an organic solvent. It is made for the purpose of providing the manufacturing method of a porous structure, and the artificial leather and synthetic leather obtained by this method.

As a result of intensive studies to solve the above problems, the present inventors have made (A) an aqueous polyurethane aqueous dispersion and (B) a molecular unit composed of a polyoxyethylene group having an average molecular weight of 100 to 2,000. A urethane prepolymer-terminated isocyanate block aqueous dispersion having 10 to 40% by mass in the skeleton, and (C) a mixed liquid containing a tertiary amine is applied to a substrate such as a nonwoven fabric, a woven fabric, a knitted fabric, and dry heat It was found that the porous structure obtained by drying or drying after moist heat heating has performance comparable to that of artificial leather or synthetic leather manufactured using solvent-based polyurethane in strength, texture, etc. Based on this, the present invention has been completed.
That is, the present invention
(1) (A) Aqueous polyurethane water dispersion, (B) Urethane prepolymer terminal isocyanate block water dispersion having 10 to 40% by mass of structural units composed of polyoxyethylene groups having an average molecular weight of 100 to 2,000 in the molecular skeleton. And (C) a mixed liquid containing a tertiary amine, after applying to the substrate, drying after dry heat drying or wet heat heating, a method for producing a porous structure,
(2) An aqueous polyurethane aqueous dispersion (A) is an isocyanate group-terminated prepolymer obtained by reacting (a) a polyol compound and (b) a polyisocyanate compound, and a nonionic surfactant having an HLB of 7 to 16. 2. The porous structure according to item 1, which is an aqueous polyurethane aqueous dispersion obtained by performing chain extension reaction with a polyamine compound having two or more amino groups and / or imino groups after being dispersed in water. Body manufacturing method,
(3) An isocyanate group-terminated prepolymer obtained by reacting (A) an aqueous polyurethane aqueous dispersion with (a) a polyol compound, (b) a polyisocyanate compound, and (c) a chain extender. A water-based polyurethane aqueous dispersion obtained by dispersing in water using a nonionic surfactant of (d) and then subjecting it to a chain extension reaction with a polyamine compound having two or more amino groups and / or imino groups. A method for producing the porous structure according to the item,
(4) Among the isocyanate group-terminated prepolymers obtained by reacting (A) an aqueous polyurethane aqueous dispersion with (a) a polyol compound, (b) a polyisocyanate compound, and (e) a compound that imparts an ionic hydrophilic group. 2. The porosity according to item 1, which is an aqueous polyurethane aqueous dispersion obtained by dispersing a Japanese product in water and then subjecting it to a chain extension reaction with (d) a polyamine compound having two or more amino groups and / or imino groups. Manufacturing method of structure,
(5) An aqueous polyurethane aqueous dispersion (A) is obtained by reacting (a) a polyol compound, (b) a polyisocyanate compound, (e) a compound imparting an ionic hydrophilic group, and (c) a chain extender. An aqueous polyurethane aqueous dispersion obtained by dispersing a neutralized product of an isocyanate group-terminated prepolymer in water and then (d) subjecting it to a chain extension reaction with a polyamine compound having two or more amino groups and / or imino groups. The method for producing a porous structure according to Item 1,
(6) Urethane prepolymer terminal isocyanate block aqueous dispersion having (A) aqueous polyurethane water dispersion and (B) 10 to 40% by mass of a structural unit composed of polyoxyethylene groups having an average molecular weight of 100 to 2,000 in the molecular skeleton. The method for producing a porous structure according to Item 1, wherein the mass ratio to the product is (A) :( B) = 10: 90 to 90:10 in terms of solid content,
(7) Artificial leather obtained by the method for producing a porous structure according to any one of items 1 to 6, and
(8) A synthetic leather obtained by the method for producing a porous structure according to any one of Items 1 to 6,
Is to provide.

  The method for producing a porous structure of the present invention uses a mixed solution containing an aqueous polyurethane aqueous dispersion and a urethane prepolymer-terminated isocyanate block aqueous dispersion, and this component is excellent in the stability of the treatment bath. Thus, an artificial leather or a synthetic leather having a porous structure having open cells excellent in texture and strength can be produced stably by a simple method. According to the method of the present invention, it is possible to reduce problems such as air pollution and water pollution caused by the solvent discharged when manufacturing using conventional solvent-based polyurethane, solvent recovery labor, and the labor environment of workers. It becomes.

In the method for producing a porous structure of the present invention, (A) an aqueous polyurethane aqueous dispersion and (B) 10 to 40 mass of a structural unit consisting of a polyoxyethylene group having an average molecular weight of 100 to 2,000 in the molecular skeleton. % Of urethane prepolymer-terminated isocyanate block aqueous dispersion and (C) a mixture containing a tertiary amine is applied to the substrate, and then dried after dry heat drying or wet heat heating.
Examples of the aqueous polyurethane aqueous dispersion (A) used in the production method of the present invention include an aqueous dispersion in which polyurethane is emulsified and dispersed or solubilized in water. Among these, a forced emulsification type polyurethane water dispersion in which polyurethane is emulsified and dispersed using an emulsifier and a self-emulsification type polyurethane water dispersion that can be emulsified and dispersed without using an emulsifier can be suitably used.
The forced emulsification type polyurethane aqueous dispersion is an isocyanate group-terminated prepolymer obtained by reacting (a) a polyol compound, (b) a polyisocyanate compound, and (c) a chain extender, if necessary. Is a polyurethane aqueous dispersion obtained by dispersing in water using a nonionic surfactant having a molecular weight of 7 to 16 and then chain-extending with (d) a polyamine compound having two or more amino groups and / or imino groups. is there. In the method of the present invention, HLB refers to a value calculated by the Griffin equation.
A self-emulsifying polyurethane aqueous dispersion reacts (a) a polyol compound, (b) a polyisocyanate compound, (e) a compound that imparts an ionic hydrophilic group, and (c) a chain extender, if necessary. A polyurethane aqueous dispersion obtained by dispersing a neutralized isocyanate group-terminated prepolymer obtained in the above step in water and then subjecting it to a chain extension reaction with a polyamine compound having two or more amino groups and / or imino groups (d) It is.

  There is no restriction | limiting in particular in (a) polyol compound used for this invention method, For example, the polyester polyol, polycarbonate polyol, polyether polyol, etc. which have a 2 or more hydroxyl group can be mentioned. Examples of the polyester polyol include polyethylene adipate, polybutylene adipate, polyethylene butylene adipate, polyhexamethylene isophthalate adipate, polyethylene succinate, polybutylene succinate, polyethylene sebacate, polybutylene sebacate, poly-ε-caprolactone diol, Poly (3-methyl-1,5-pentylene) adipate, polycondensate of 1,6-hexanediol and dimer acid, copolycondensate of 1,6-hexanediol, adipic acid and dimer acid, nonanediol and dimer Examples thereof include acid polycondensates, and copolycondensates of ethylene glycol, adipic acid and dimer acid. Examples of the polycarbonate polyol include polytetramethylene carbonate diol, polyhexamethylene carbonate diol, and poly-1,4-cyclohexanedimethylene carbonate diol. Examples of the polyether polyol include homopolymers such as polyethylene glycol, polypropylene glycol, and polytetramethylene glycol, random copolymers and block copolymers of ethylene oxide and propylene oxide, ethylene oxide and butylene oxide, and the like. Furthermore, a polyether ester polyol having an ether bond and an ester bond can also be used. These polyol compounds can be used individually by 1 type, or can also be used in combination of 2 or more type.

(B) The polyisocyanate compound used in the method of the present invention is not particularly limited, and examples thereof include an aliphatic polyisocyanate compound having two or more isocyanate groups, an alicyclic polyisocyanate compound, and an aromatic polyisocyanate compound. it can. Examples of the aliphatic polyisocyanate compound include hexamethylene diisocyanate and trimethylhexamethylene diisocyanate. Examples of the alicyclic polyisocyanate compound include isophorone diisocyanate, hydrogenated xylylene diisocyanate, dicyclohexylmethane diisocyanate, norbornane diisocyanate, and 1,3-bis (isocyanatomethyl) cyclohexane. Examples of the aromatic polyisocyanate compound include tolylene diisocyanate, diphenylmethane diisocyanate, naphthalene diisocyanate, tolidine diisocyanate, xylylene diisocyanate, tetramethylxylylene diisocyanate, and the like. These polyisocyanate compounds can be used individually by 1 type, or can also be used in combination of 2 or more type. Among these, an aliphatic polyisocyanate compound and an alicyclic polyisocyanate compound can be suitably used because they give a non-yellowing film, and include hexamethylene diisocyanate, isophorone diisocyanate, dicyclohexylmethane diisocyanate, norbornane diisocyanate and 1,3-bis (isocyanatomethyl) cyclohexane can be particularly preferably used.
In the method of the present invention, the chain extender used as necessary is, for example, ethylene glycol, propylene glycol, neopentyl glycol, 1,4-butanediol, 1,6-hexanediol, trimethylolpropane, penta Examples include low molecular weight polyhydric alcohols such as erythritol and sorbitol, low molecular weight polyamines such as ethylenediamine, propylenediamine, hexamethylenediamine, diaminocyclohexylmethane, piperazine, 2-methylpiperazine, isophoronediamine, diethylenetriamine, and triethylenetetramine. . These chain extenders can be used individually by 1 type, or can also be used in combination of 2 or more type.

In the self-emulsifying type polyurethane water dispersion used in the method of the present invention, there is no particular limitation on the compound (e) that imparts an ionic hydrophilic group to be introduced into the urethane skeleton, such as a compound that imparts an anionic hydrophilic group, a cationic hydrophilic group Examples thereof include a compound imparting a group. Examples of the compound that imparts an anionic hydrophilic group include a compound in which the anionic hydrophilic group is a carboxyl group and the active hydrogen is a hydroxyl group hydrogen. Examples of such compounds include 2,2-dimethylolpropionic acid, 2,2-dimethylolbutanoic acid, and the like. In addition, a polyester polyol having a pendant carboxyl group obtained by reacting a dicarboxylic acid such as an aliphatic dicarboxylic acid, an alicyclic dicarboxylic acid, or an aromatic dicarboxylic acid with a diol having a carboxyl group can also be used. In the reaction, a diol having no carboxyl group can be mixed with a diol having a carboxyl group. These compounds imparting an anionic hydrophilic group can be used alone or in combination of two or more. These anionic hydrophilic groups include, for example, trimethylamine, triethylamine, tri-n-propylamine, tributylamine, N-methyldiethanolamine, N, N-dimethylmonoethanolamine, amines such as triethanolamine, potassium hydroxide, Sodium hydroxide, ammonia or the like is used after neutralization before or after the preparation of the isocyanate group-terminated prepolymer.
As the compound that imparts a cationic hydrophilic group, alkanolamines can be preferably used, and examples thereof include N-methyldiethanolamine, N-ethyldiethanolamine, and triethanolamine. These alkanolamines can be used individually by 1 type, or can also be used in combination of 2 or more type. These cationic hydrophilic groups can be neutralized with inorganic or organic acids such as hydrochloric acid, nitric acid, formic acid, and acetic acid, or quaternized with dimethyl sulfate, diethyl sulfate, benzyl chloride, epichlorohydrin, and the like. Use.

There is no restriction | limiting in particular in the manufacturing method of the isocyanate group terminal prepolymer used for this invention, For example, it can manufacture by what is called a one-stage type so-called one-shot method, a multistage type isocyanate polyaddition reaction method, etc. The reaction temperature is preferably 40 to 150 ° C. At this time, a reaction catalyst such as dibutyltin dilaurate, stannous octoate, dibutyltin-2-ethylhexanoate, triethylamine, triethylenediamine, N-methylmorpholine can be added as necessary. Moreover, the organic solvent which does not react with an isocyanate group can be added during reaction or after completion | finish of reaction. Examples of such an organic solvent include acetone, methyl ethyl ketone, toluene, tetrahydrofuran, dioxane, dimethylformamide, N-methylpyrrolidone, and the like.
In the forced emulsification type polyurethane water dispersion used in the method of the present invention, when the isocyanate-terminated prepolymer is dispersed in water, it is preferable to use a nonionic surfactant having an HLB of 7 to 16, and an HLB of 9 to 15 It is more preferable to use a nonionic surfactant. When the HLB is less than 7, it is difficult to disperse the isocyanate-terminated prepolymer, and even when dispersible, the stability may be deteriorated. When the HLB exceeds 16, it is difficult to emulsify and disperse the isocyanate-terminated prepolymer, and the water resistance of the resulting porous structure may be inferior even when dispersible. The structure of the nonionic surfactant having an HLB of 7 to 16 is not particularly limited, and examples thereof include polyoxyethylene distyryl phenyl ether type nonionic surfactant, polyoxyethylene propylene distyryl phenyl ether type nonionic surfactant, Examples thereof include polyoxyethylene tristyryl phenyl ether type nonionic surfactant, polyoxyethylene propylene tristyryl phenyl ether type nonionic surfactant, and pluronic type nonionic surfactant. These nonionic surfactants can be used individually by 1 type, or can also be used in combination of 2 or more type. The amount of these nonionic surfactants to be used can be appropriately selected depending on the hydrophilicity derived from the polyoxyethylene of the isocyanate group-terminated prepolymer, which is the substance to be emulsified, but usually 100 masses of the isocyanate group-terminated prepolymer. The amount is preferably 0.5 to 10 parts by mass, and more preferably 1 to 6 parts by mass with respect to parts. If the amount of the nonionic surfactant used is less than 0.5 parts by mass with respect to 100 parts by mass of the isocyanate group-terminated prepolymer, it may be difficult to obtain a stable emulsified dispersion state. When the usage-amount of a nonionic surfactant exceeds 10 mass parts with respect to 100 mass parts of isocyanate group terminal prepolymers, there exists a possibility that the water resistance of the porous structure obtained may fall.

In the self-emulsifying type polyurethane water dispersion used in the method of the present invention, the neutralized product of the isocyanate group-terminated prepolymer can be emulsified and dispersed in water without adding an emulsifier. Sixteen nonionic surfactants can be used. In the isocyanate group-terminated prepolymer having an anionic hydrophilic group, for example, higher fatty acid salts, resin acid salts, acidic fatty alcohols, sulfuric acid ester salts, sulfonic acid higher alkyl salts, alkylaryl sulfonates, sulfonated castor oil, sulfosuccinic acid An anionic surfactant such as an ester can be used in combination to maintain the emulsifying property.
In the method of the present invention, when the isocyanate group-terminated prepolymer or the neutralized product of the isocyanate group-terminated prepolymer is emulsified and dispersed in water, it is preferable to use mechanical shearing force because phase inversion emulsification occurs. There is no restriction | limiting in particular in the emulsification apparatus which gives a mechanical shearing force, For example, a homomixer, a homogenizer, etc. can be mentioned. The isocyanate group-terminated prepolymer or the neutralized product of the isocyanate group-terminated prepolymer should be emulsified and dispersed in water at a temperature ranging from room temperature to 40 ° C. in order to suppress the reaction between the isocyanate group and water or nonionic surfactant as much as possible. Is preferred. Furthermore, reaction inhibitors such as phosphoric acid, sodium dihydrogen phosphate, disodium hydrogen phosphate, paratoluenesulfonic acid, adipic acid, and benzoyl chloride can be added as necessary.

In the method of the present invention, after an isocyanate group-terminated prepolymer or a neutralized product of an isocyanate group-terminated prepolymer is emulsified and dispersed in water, (d) a polyamine compound having two or more amino groups and / or imino groups is used. It is preferable to carry out a chain extension reaction to obtain (A) an aqueous polyurethane aqueous dispersion. (d) Examples of polyamine compounds having two or more amino groups and / or imino groups include ethylenediamine, propylenediamine, tetramethylenediamine, hexamethylenediamine, diaminocyclohexylmethane, piperazine, hydrazine, 2-methylpiperazine, and isophorone. Diamines such as diamine, norbornanediamine, diaminodiphenylmethane, tolylenediamine, xylylenediamine, polyamines such as diethylenetriamine, triethylenetetramine, tetraethylenepentamine, iminobispropylamine, tris (2-aminoethyl) amine, Water-soluble amine derivatives such as amidoamines derived from secondary amines and monocarboxylic acids, monoketimines of diprimary amines, oxalic acid dihydrazide, malonic acid dihydrazide, koha Succinic acid dihydrazide, glutaric acid dihydrazide, adipic acid dihydrazide, sebacic acid dihydrazide, maleic acid dihydrazide, fumaric acid dihydrazide, itaconic acid dihydrazide, 1,1'-ethylenehydrazine, 1,1'-trimethylenehydrazine, 1,1'- And hydrazine derivatives such as (1,4-butylene) dihydrazine. These polyamine compounds can be used individually by 1 type, or can also be used in combination of 2 or more type.
In the method of the present invention, the chain extension reaction of the isocyanate group-terminated prepolymer or the neutralized product of the isocyanate group-terminated prepolymer has (d) two or more amino groups and / or imino groups in the emulsified dispersion of these prepolymers. It can be carried out by adding a polyamine compound, or (d) by adding an emulsified dispersion of a prepolymer to a polyamine compound having two or more amino groups and / or imino groups. The chain extension reaction is preferably performed at a reaction temperature of 20 to 40 ° C. When the isocyanate group-terminated prepolymer is synthesized using an organic solvent, it is preferable to remove the organic solvent by distillation under reduced pressure after the chain extension reaction is completed.

The (B) urethane prepolymer-terminated isocyanate block aqueous dispersion used in the production method of the present invention is a urethane prepolymer having hydrophilicity and thermal reactivity, and is a compound in which the isocyanate group at the end is blocked with a blocking agent. is there. The urethane prepolymer-terminated isocyanate block aqueous dispersion can be stored for a long time in the state of an aqueous solution. The blocking agent is desorbed by heating to regenerate active isocyanate groups, and within or between the urethane prepolymer molecules. A polyaddition reaction can be performed to form a polyurethane polymer, or an addition reaction with other functional groups can be performed. The desorption temperature of the blocking agent is preferably 50 to 150 ° C. The urethane prepolymer-terminated isocyanate block aqueous dispersion is obtained by reacting (f) a compound having two or more active hydrogens, (g) a polyisocyanate compound, and, if necessary, (h) a chain extender. The terminal isocyanate group of the polymer can be produced by blocking with (i) a blocking agent.
The (B) urethane prepolymer-terminated isocyanate block aqueous dispersion used in the method of the present invention has 10 to 40% by mass of a structural unit composed of polyoxyethylene groups having an average molecular weight of 100 to 2,000 as a hydrophilic component in the molecular skeleton. More preferably, it has 15-35 mass%. When the average molecular weight of the polyoxyethylene group is less than 100, it is difficult to control the reaction, and the cohesive force of the polyurethane resin becomes too high, and it may be difficult to disperse the urethane prepolymer having a blocked isocyanate group in water. is there. When the average molecular weight of the polyoxyethylene group exceeds 2,000, shrinkage during drying is large, and it may be difficult to obtain a sufficient porous structure. Further, when the amount of the structural unit comprising a polyoxyethylene group in the molecular skeleton is less than 10% by mass, it is difficult to disperse the urethane prepolymer having a blocked isocyanate group in water, or even if it can be dispersed over time. May cause gelation and separation, making it difficult to use. If the amount of the structural unit composed of polyoxyethylene groups in the molecular skeleton exceeds 40% by mass, the polyurethane resin does not form a film, which may make it difficult to form a porous structure.

  (F) The compound having two or more active hydrogens used in the method of the present invention is not particularly limited, and for example, a compound having two or more hydroxyl groups, carboxyl groups, amino groups, mercapto groups, etc. in the terminal or molecule A polyether compound, a polyester compound, a polyether ester compound, a polycarbonate compound and the like can be suitably used. Examples of polyether compounds include homopolymers such as ethylene oxide, propylene oxide, styrene oxide, epichlorohydrin, two or more random or block copolymers thereof, addition polymers to polyhydric alcohols, and the like. be able to. Examples of the polyester compound and the polyether ester compound include polysaturated carboxylic acids such as adipic acid, succinic acid, phthalic acid, and maleic anhydride, polyunsaturated carboxylic acids, acid anhydrides thereof, and the like. -Polysaturated alcohols such as butanediol, 1,6-hexanediol, neopentyl glycol and trimethylolpropane, unsaturated alcohols, relatively low molecular weight polyethylene glycols, polypropylene glycols and other polyalkylene ether glycols, mixtures thereof, etc. Mainly linear or branched condensation products obtained from the above, polyesters obtained from lactones or hydroxy acids, and polyether esters obtained by adding ethylene oxide, propylene oxide, etc. to previously produced polyesters It is possible. Examples of the polycarbonate compound include polytetramethylene carbonate diol, polyhexamethylene carbonate diol, poly-1,4-cyclohexanedimethylene carbonate diol, and the like.

  Examples of the (g) polyisocyanate compound used in the method of the present invention include an aliphatic polyisocyanate compound, an alicyclic polyisocyanate compound, and an aromatic polyisocyanate compound. Examples of the aliphatic polyisocyanate compound include hexamethylene diisocyanate and trimethylhexamethylene diisocyanate. Examples of the alicyclic polyisocyanate compound include isophorone diisocyanate, hydrogenated xylylene diisocyanate, dicyclohexylmethane diisocyanate, norbornane diisocyanate, and 1,3-bis (isocyanatomethyl) cyclohexane. Examples of the aromatic polyisocyanate compound include tolylene diisocyanate, diphenylmethane diisocyanate, naphthalene diisocyanate, tolidine diisocyanate, xylylene diisocyanate, tetramethylxylylene diisocyanate, and the like. These polyisocyanate compounds can be used individually by 1 type, or can also be used in combination of 2 or more type. Among these, an aliphatic polyisocyanate compound and an alicyclic polyisocyanate compound can be preferably used because they give a non-yellowing film, and include hexamethylene diisocyanate, isophorone diisocyanate, dicyclohexylmethane diisocyanate, norbornane diisocyanate, 1, 3-bis (isocyanatomethyl) cyclohexane can be particularly preferably used.

The (h) chain extender used in the method of the present invention is not particularly limited, and examples thereof include glycols such as ethylene glycol, diethylene glycol, 1,4-butanediol, and 1,6-hexanediol, glycerin, trimethylolpropane, and pentaerythritol. And polyhydric alcohols such as ethylenediamine, hexamethylenediamine and piperazine, amino alcohols such as monoethanolamine and diethanolamine, thiodiglycols such as thiodiethylene glycol, and water.
In the method of the present invention, (f) a method for producing a urethane prepolymer obtained by reacting a compound having two or more active hydrogens, (g) a polyisocyanate compound, and, if necessary, (h) a chain extender There is no particular limitation, and for example, it can be produced by a one-stage so-called one-shot method, a multi-stage isocyanate polyaddition reaction method, or the like. Although there is no restriction | limiting in particular also in reaction conditions, It is preferable that reaction temperature is 150 degrees C or less, and it is more preferable that it is 50-120 degreeC. Moreover, although the isocyanate group / active hydrogen equivalent ratio is 1 or more, it is necessary to form a blocked isocyanate group having thermal reactivity, so that a free isocyanate group needs to remain in the obtained urethane prepolymer. There is. The content of free isocyanate groups is preferably 1 to 10% by mass and more preferably 2 to 7% by mass in the urethane prepolymer. Even if the content of free isocyanate groups is less than 1% by mass or more than 10% by mass, the water dispersibility of the resulting polyurethane prepolymer having blocked isocyanate groups becomes unstable, and separation occurs over time. Or gelation.

  In the method of the present invention, the urethane prepolymer blocking agent is not particularly limited as long as it reacts with an isocyanate group, is hydrophilic, and can easily be eliminated by regenerating the active isocyanate group under the conditions of the thermal reaction. Examples thereof include bisulfite and oxime. Among these, bisulfite can be particularly preferably used because of its low desorption temperature. Since the reaction between the urethane prepolymer and bisulfite is an exothermic reaction and is a competitive reaction between bisulfite and water, the reaction temperature is 50 to selectively perform sufficient blocking with bisulfite. It is preferable that it is below ° C, and it is more preferable that it is 20-40 ° C. After completion of the reaction, it is diluted with water to an appropriate concentration to obtain a hydrophilic and heat-reactive urethane prepolymer-terminated isocyanate block aqueous dispersion. This blocked product can be stored for a long time in the state of an aqueous solution, and when heated to 50 to 150 ° C., the bisulfite of the blocking agent is dissociated to regenerate active isocyanate groups. A polymerization addition reaction can be performed inside or between molecules to form a polyurethane polymer, or an addition reaction to other functional groups can be performed.

In the production method of the present invention, the mass ratio of (A) aqueous polyurethane aqueous dispersion and (B) urethane prepolymer-terminated isocyanate block aqueous dispersion is (A) :( B) = 10: 90 to solid content conversion. 90:10 is preferable, and 30:70 to 70:30 is more preferable. When the mass ratio in terms of solid content is less than (A) :( B) = 10: 90, and the amount of the aqueous polyurethane aqueous dispersion is small, the strength of the porous structure becomes insufficient and sufficient porosity is obtained. The structure may not be formed. If the mass ratio in terms of solid content exceeds (A) :( B) = 90: 10 and the amount of the urethane prepolymer-terminated isocyanate block aqueous dispersion is small, a sufficient porous structure may not be formed.
In the production method of the present invention, (C) a tertiary amine is used in order to accelerate the polymerization of the (B) urethane prepolymer-terminated isocyanate block aqueous dispersion. The (C) tertiary amine to be used is not particularly limited, and examples thereof include water-soluble tertiary amines such as triethylenediamine, trimethylamine, triethylamine and triallylamine. The mass ratio of (A) aqueous polyurethane aqueous dispersion and (B) urethane prepolymer-terminated isocyanate block aqueous dispersion to (C) tertiary amine is {(A) + (B) }: (C) = 100: 10 to 100: 1 is preferable. When the mass ratio in terms of solid content is less than {(A) + (B)} :( C) = 100: 10 and the amount of tertiary amine is large, the effect of promoting the polymerization addition reaction is not changed, and the catalyst The amount may be excessive. If the mass ratio in terms of solid content exceeds {(A) + (B)} :( C) = 100: 1 and the amount of tertiary amine is small, the catalytic action becomes insufficient and the polymerization addition reaction is accelerated. Otherwise, a satisfactory porous structure may not be obtained.

In the production method of the present invention, a mixed solution of (A) an aqueous polyurethane aqueous dispersion and (B) a urethane prepolymer-terminated isocyanate block aqueous dispersion is optionally provided with a surfactant, a thickener, and migration prevention. Additives such as agents, leveling agents, preservatives, antifungal agents, and crosslinking agents can be added. These additives were mixed until uniform, and (A) aqueous polyurethane aqueous dispersion, (B) urethane prepolymer-terminated isocyanate block aqueous dispersion, and (C) tertiary amine were used to obtain the desired porosity. A sex structure can be obtained.
In the method of the present invention, (A) aqueous polyurethane aqueous dispersion, (B) urethane prepolymer-terminated isocyanate block aqueous dispersion, and (C) a base material to which a liquid mixture containing a tertiary amine is applied is a liquid mixture There is no particular limitation as long as it can adhere and can form a film with a resin component having a porous structure after drying. Examples of such a base material include release paper, paper, plastic film, glass plate, metal plate, natural fibers such as wool, silk, and cotton, synthetic fibers such as polyamide, polyester, and acrylic, and blends and mixed fibers thereof. Examples thereof include woven fabrics, knitted fabrics and nonwoven fabrics produced by mixed knitting. Among these substrates, non-woven fabrics using polyamide fibers, polyester fibers or acrylic fibers can be used particularly suitably because they can produce artificial leather and synthetic leather of a quality close to natural leather. Can do.

In the method of the present invention, artificial leather can be produced using a nonwoven fabric having a fiber layer having a three-dimensional structure similar to the collagen fiber structure of leather as a base material. It is preferable to use ultrafine fibers of 0.1 denier or less for the surface portion of the substrate. By using ultrafine fibers for the surface portion, an excellent leather-like feel can be obtained. Artificial leather can be made into a suede type or a silver surface type by surface finishing. Synthetic leather can be finished by coating a polyamide resin or a polyurethane resin on a porous structure formed using a woven fabric, a knitted fabric, a non-woven fabric or the like as a base material.
In the production method of the present invention, (A) an aqueous polyurethane aqueous dispersion, (B) a urethane prepolymer-terminated isocyanate block aqueous dispersion, and (C) a mixed liquid containing a tertiary amine, a woven fabric, a knitted fabric, A porous material useful as artificial leather or synthetic leather is applied to a substrate such as non-woven fabric by a method such as impregnation, coating, or spraying, and then the applied substrate is dried after dry heat drying or moist heat heating with steam. A sex structure can be obtained. There is no particular limitation on the machine and method for impregnating, coating, spraying, etc. the above-mentioned mixed solution on the substrate, and the concentration and processing conditions of the mixed solution can also be appropriately selected. There is no particular limitation on the drying method, for example, dry heat drying using a pin tenter or the like, wet heat heating using a high tenpalature steamer (HTS), a high pressure steamer (HPS), or the like, Examples of the drying method include far-infrared heating and microwave heating. It is also possible to dry through a washing step with hot water or cold water after heat drying.

Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples.
In Examples and Comparative Examples, the porous structures were evaluated by the following methods.
(1) Porous structure The cross section was observed using a scanning electron microscope [Hitachi Ltd., S-2400].
A: A dense porous structure is formed.
Δ: Formation of a porous structure is partially observed.
X: Formation of a porous structure is not seen.
(2) Tear strength Measured according to JIS L 1906 5.4. (C) pendulum method.
(3) Texture It evaluated in five steps from the 1st grade (coarse) to the 5th grade (flexible) by touch.
Further, in Synthesis Examples 1 to 7, Synthesis Example 9 and Comparative Synthesis Example 4, the viscosity was measured at 60 rpm using a BM viscometer and No. 1 rotor, and Synthesis Example 8, Comparative Synthesis Example 2, Example 11 and In Comparative Example 5, measurement was performed at 60 rpm using a BM viscometer and a No. 4 rotor.

Synthesis example 1 (aqueous polyurethane aqueous dispersion)
In a four-necked flask equipped with a stirrer, reflux condenser, thermometer and nitrogen inlet tube, 75.9 g of polytetramethylene glycol (average molecular weight 1,000), polyoxyethylene polyoxypropylene random copolymer glycol (average molecular weight) 1,000, oxyethylene group content 70% by mass) 19.0 g, trimethylolpropane 2.5 g, dibutyltin dilaurate 0.001 g and methyl ethyl ketone 60 g were mixed and mixed uniformly, and then 42.6 g of dicyclohexylmethane diisocyanate was added. The mixture was reacted at 75 ° C. for 300 minutes to obtain a methyl ethyl ketone solution of a urethane prepolymer having a free isocyanate group content of 1.7% by mass relative to the solid content. After cooling this solution to 30 ° C., 0.1 g of decyl phosphate ester and 6.0 g of polyoxyethylene tristyryl phenyl ether (HLB15) are added and mixed uniformly, and 260 g of water is gradually added to phase inversion emulsification and dispersion. I let you. Furthermore, a polyamine aqueous solution in which 5.3 g of piperazine and 0.8 g of diethylenetriamine were dissolved in 18.0 g of water was added, and the mixture was stirred for 90 minutes to obtain a polyurethane dispersion. Thereafter, the solvent was removed at 50 ° C. under reduced pressure to obtain a stable aqueous polyurethane water dispersion A1 having a solid content of 35.0% by mass, a viscosity of 45 mPa · s, and an average particle size of 0.32 μm.
Synthesis example 2 (aqueous polyurethane aqueous dispersion)
In the same reactor as in Synthesis Example 1, 74.5 g of polytetramethylene glycol (average molecular weight 1,000), polyoxyethylene polyoxypropylene random copolymer glycol (average molecular weight 1,000, oxyethylene group content 70% by mass) ) 17.2 g, 1.3 g of 1,4-butanediol, 1.9 g of trimethylolpropane, 0.001 g of dibutyltin dilaurate and 60 g of methyl ethyl ketone were mixed and mixed uniformly, and then 45.1 g of dicyclohexylmethane diisocyanate was added, and 75 The reaction was carried out at 300 ° C. for 300 minutes to obtain a methyl ethyl ketone solution of a urethane prepolymer having a free isocyanate group content of 1.9% by mass relative to the solid content. After cooling this solution to 30 ° C., 0.1 g of decyl phosphate ester and 6.0 g of polyoxyethylene tristyryl phenyl ether (HLB15) are added and mixed uniformly, and 260 g of water is gradually added to phase inversion emulsification and dispersion. I let you. Further, an aqueous polyamine solution in which 5.6 g of piperazine and 0.9 g of diethylenetriamine were dissolved in 18.0 g of water was added, and the mixture was stirred for 90 minutes to obtain a polyurethane dispersion. Thereafter, the solvent was removed at 50 ° C. under reduced pressure to obtain a stable aqueous polyurethane water dispersion A2 having a solid content of 35.0% by mass, a viscosity of 57 mPa · s, and an average particle size of 0.30 μm.
Synthesis example 3 (aqueous polyurethane aqueous dispersion)
In the same reactor as in Synthesis Example 1, 63.0 g of polytetramethylene glycol (average molecular weight 1,000) 6.0 g of 2,2-dimethylolbutanoic acid, 1.4 g of trimethylolpropane, 0.005 g of dibutyltin dilaurate And 47 g of methyl ethyl ketone were added and mixed uniformly, and then 39.6 g of dicyclohexylmethane diisocyanate was added and reacted at 85 ° C. for 250 minutes. Got. After cooling this solution to 30 ° C., 4.0 g of triethylamine was added for neutralization, and 160 g of water was gradually added to emulsify and disperse. Further, a polyamine aqueous solution in which 6.4 g of piperazine was dissolved in 25.0 g of water was added, and stirred for 90 minutes to obtain a polyurethane dispersion. Thereafter, the solvent was removed at 50 ° C. under reduced pressure to obtain a stable aqueous polyurethane water dispersion A3 having a solid content of 35.3% by mass, a viscosity of 40 mPa · s, and an average particle size of 0.13 μm.
Synthesis Example 4 (aqueous polyurethane water dispersion)
In a reaction apparatus similar to Synthesis Example 1, 59.1 g of polytetramethylene glycol (average molecular weight 1,000), 1.2 g of 1,4-butanediol, 6.0 g of 2,2-dimethylolbutanoic acid, trimethylolpropane After adding 1.4 g, 0.005 g of dibutyltin dilaurate and 47 g of methyl ethyl ketone and mixing them uniformly, 42.3 g of dicyclohexylmethane diisocyanate was added and reacted at 85 ° C. for 250 minutes to give a free isocyanate group content of 1. A methyl ethyl ketone solution of 7% by mass of urethane prepolymer was obtained. After cooling this solution to 30 ° C., 4.0 g of triethylamine was added for neutralization, and 160 g of water was gradually added to emulsify and disperse. Further, a polyamine aqueous solution in which 6.3 g of piperazine was dissolved in 25.0 g of water was added, and stirred for 90 minutes to obtain a polyurethane dispersion. Thereafter, the solvent was removed at 50 ° C. under reduced pressure to obtain a stable aqueous polyurethane aqueous dispersion A4 having a solid content of 34.9% by mass, a viscosity of 50 mPa · s, and an average particle size of 0.12 μm.

Synthesis example 5 (urethane prepolymer terminal isocyanate block aqueous dispersion)
In a reactor similar to that of Synthesis Example 1, 76.7 g of polytetramethylene glycol (average molecular weight 1,000), 29.8 g of polyethylene glycol (average molecular weight 400) and 43.5 g of hexamethylene diisocyanate were charged and mixed uniformly. The urethane prepolymer having a free isocyanate group content of 6.0% by mass and a polyoxyethylene group content of 19.9% by mass was obtained by reacting at 100 ° C. for 60 minutes. After cooling this urethane prepolymer to 30 ° C., 40 g of ethanol was added and mixed uniformly, an aqueous solution in which 22.4 g of anhydrous sodium bisulfite was dissolved in 41.7 g of water was added, and NCO peak was measured by infrared absorption spectrum measurement. The blocking reaction was carried out at 30 ° C. until disappearance. After completion of the reaction, 268 g of water was added to obtain a stable urethane prepolymer-terminated isocyanate block aqueous dispersion B1 having a solid content of 30.0% by mass and a viscosity of 62 mPa · s.
Synthesis Example 6 (urethane prepolymer-terminated isocyanate block aqueous dispersion)
In a reactor similar to Synthesis Example 1, 82.6 g of polytetramethylene glycol (average molecular weight 1,000), 30.4 g of polyethylene glycol (average molecular weight 1,000), and 37.0 g of hexamethylene diisocyanate are charged and mixed uniformly. Then, it was made to react at 100 degreeC for 60 minute (s), and the urethane prepolymer whose free isocyanate group content with respect to solid content is 6.0 mass% and whose content of polyoxyethylene group is 20.3 mass% was obtained. After cooling this urethane prepolymer to 30 ° C., 40 g of ethanol was added and mixed uniformly, an aqueous solution in which 22.4 g of anhydrous sodium bisulfite was dissolved in 41.6 g of water was added, and NCO peak was measured by infrared absorption spectrum measurement. The blocking reaction was carried out at 30 ° C. until disappearance. After completion of the reaction, 268 g of water was added to obtain a stable urethane prepolymer-terminated isocyanate block aqueous dispersion B2 having a solid content of 30.0% by mass and a viscosity of 37 mPa · s.
Synthesis example 7 (urethane prepolymer terminal isocyanate block aqueous dispersion)
In a reactor similar to Synthesis Example 1, 67.0 g of polytetramethylene glycol (average molecular weight 1,000), 29.4 g of polyethylene glycol (average molecular weight 200) and 53.5 g of hexamethylene diisocyanate were charged and mixed uniformly. The urethane prepolymer having a free isocyanate group content of 6.0% by mass and a polyoxyethylene group content of 19.6% by mass was obtained by reacting at 100 ° C. for 30 minutes. After cooling this urethane prepolymer to 30 ° C., 40 g of ethanol was added and mixed uniformly, an aqueous solution in which 22.2 g of anhydrous sodium bisulfite was dissolved in 41.2 g of water was added, and NCO peak was measured by infrared absorption spectrum measurement. The blocking reaction was carried out at 30 ° C. until disappearance. After completion of the reaction, 269 g of water was added to obtain a stable urethane prepolymer-terminated isocyanate block aqueous dispersion B3 having a solid content of 30.0% by mass and a viscosity of 52 mPa · s.
Synthesis Example 8 (urethane prepolymer terminal isocyanate block aqueous dispersion)
In the same reactor as in Synthesis Example 1, 85.1 g of polytetramethylene glycol (average molecular weight 1,000), 30.0 g of polyethylene glycol (average molecular weight 1,800) and 34.9 g of hexamethylene diisocyanate are charged and mixed uniformly. Then, it was made to react at 100 degreeC for 60 minute (s), and the urethane prepolymer whose free isocyanate group content with respect to solid content is 6.0 mass% and whose content of polyoxyethylene group is 20.0 mass% was obtained. After cooling this urethane prepolymer to 30 ° C., 40 g of ethanol was added and mixed uniformly, an aqueous solution in which 22.4 g of anhydrous sodium bisulfite was dissolved in 41.3 g of water was added, and NCO peak was measured by infrared absorption spectrum measurement. The blocking reaction was carried out at 30 ° C. until disappearance. After completion of the reaction, 269 g of water was added to obtain a stable urethane prepolymer-terminated isocyanate block aqueous dispersion B4 having a solid content of 30.0% by mass and a viscosity of 1,500 mPa · s.
Synthesis Example 9 (urethane prepolymer terminal isocyanate block aqueous dispersion)
In a reactor similar to Synthesis Example 1, 57.3 g of polytetramethylene glycol (average molecular weight 1,000), 45.7 g of polyethylene glycol (average molecular weight 400) and 47.0 g of hexamethylene diisocyanate were charged and mixed uniformly. The urethane prepolymer having a free isocyanate group content of 6.1% by mass and a polyoxyethylene group content of 30.4% by mass was obtained by reacting at 100 ° C. for 60 minutes. After cooling this urethane prepolymer to 30 ° C., 40 g of ethanol was added and mixed uniformly, an aqueous solution in which 22.6 g of anhydrous sodium bisulfite was dissolved in 42.0 g of water was added, and NCO peak was measured by infrared absorption spectrum measurement. The blocking reaction was carried out at 30 ° C. until disappearance. After completion of the reaction, 268 g of water was added to obtain a stable urethane prepolymer-terminated isocyanate block aqueous dispersion B6 having a solid content of 30.2% by mass and a viscosity of 33 mPa · s.

Comparative synthesis example 1 (urethane prepolymer terminal isocyanate block aqueous dispersion)
In a reaction apparatus similar to Synthesis Example 1, 19.8 g of polytetramethylene glycol (average molecular weight 1,000), 30.7 g of ethylene glycol, and 99.6 g of hexamethylene diisocyanate were charged and mixed uniformly. went. Vigorous exotherm was observed from around 60 ° C., the reaction proceeded, and the viscosity increased. When it was cooled to around 50 ° C. for dispersion in water, the urethane prepolymer solidified, so that it could not be dispersed in water, and a stable urethane prepolymer-terminated isocyanate block aqueous dispersion could not be obtained.
Comparative synthesis example 2 (urethane prepolymer terminal isocyanate block aqueous dispersion)
In the same reactor as in Synthesis Example 1, 85.6 g of polytetramethylene glycol (average molecular weight 1,000), 29.9 g of polyethylene glycol (average molecular weight 2,500), and 34.5 g of hexamethylene diisocyanate were charged and mixed uniformly. Then, it was made to react for 60 minutes at 100 degreeC, and the free isocyanate group content with respect to solid content was 6.0 mass%, and the urethane prepolymer whose content of a polyoxyethylene group is 19.9 mass% was obtained. After cooling this urethane prepolymer to 30 ° C., 40 g of ethanol was added and mixed uniformly, an aqueous solution in which 22.5 g of anhydrous sodium bisulfite was dissolved in 41.3 g of water was added, and NCO peak was measured by infrared absorption spectrum measurement. The blocking reaction was carried out at 30 ° C. until disappearance. After completion of the reaction, 269 g of water was added to obtain a stable urethane prepolymer-terminated isocyanate block aqueous dispersion B5 having a solid content of 30.0% by mass and a viscosity of 3,000 mPa · s.
Comparative synthesis example 3 (urethane prepolymer-terminated isocyanate block aqueous dispersion)
In a reactor similar to Synthesis Example 1, 103.6 g of polytetramethylene glycol (average molecular weight 1,000), 7.7 g of polyethylene glycol (average molecular weight 400) and 38.7 g of hexamethylene diisocyanate were mixed and mixed uniformly. The urethane prepolymer having a free isocyanate group content of 6.0% by mass and a polyoxyethylene group content of 5.1% by mass was obtained by reacting at 100 ° C. for 60 minutes. After cooling this urethane prepolymer to 30 ° C., 40 g of ethanol is added and mixed uniformly, and an aqueous solution in which 22.5 g of anhydrous sodium bisulfite is dissolved in 41.7 g of water is added, and a blocking reaction is performed at 30 ° C. However, the viscosity rapidly increased and a large amount of scum was generated without being dispersed in water, so that a stable aqueous dispersion could not be obtained.
Comparative synthesis example 4 (urethane prepolymer terminal isocyanate block aqueous dispersion)
In a reactor similar to Synthesis Example 1, 21.1 g of polytetramethylene glycol (average molecular weight 1,000), 75.8 g of polyethylene glycol (average molecular weight 400), and 53.1 g of hexamethylene diisocyanate were mixed and mixed uniformly. The urethane prepolymer having a free isocyanate group content of 5.9% by mass and a polyoxyethylene group content of 50.6% by mass was obtained by reacting at 100 ° C. for 60 minutes. After cooling this urethane prepolymer to 30 ° C., 40 g of ethanol was added and mixed uniformly, an aqueous solution in which 22.0 g of anhydrous sodium bisulfite was dissolved in 40.9 g of water was added, and NCO peak was measured by infrared absorption spectrum measurement. The blocking reaction was carried out at 30 ° C. until disappearance. After completion of the reaction, 269 g of water was added to obtain a stable urethane prepolymer-terminated isocyanate block aqueous dispersion B7 having a solid content of 30.1% by mass and a viscosity of 34 mPa · s.
The results of Synthesis Examples 1 to 9 and Comparative Synthesis Examples 1 to 4 are shown in Table 1.

Example 1 (impregnation processing)
To a polyester nonwoven fabric having a fiber thickness of 1.0 denier and a density of 0.40 g / cm ³ , 143 g of aqueous polyurethane aqueous dispersion A1 and 167 g of urethane prepolymer-terminated isocyanate block aqueous dispersion B1 (mass ratio (in terms of solid content) ( A) :( B) = 50: 50), 7 g of triethylenediamine and 183 g of water were mixed to prepare a treatment solution, which was pad-treated with a pickup of 250 mass%. After the pad treatment, the work cloth was heated with wet heat for 5 minutes with a high tenpulcher steamer adjusted to a temperature of 100 ° C. and a vapor pressure of 39 kPa. Next, after washing with water for 2 minutes and squeezing with a mangle, it was dried with a pin tenter adjusted to 120 ° C. to dry heat to obtain an artificial leather.
In the obtained artificial leather, a dense porous structure was formed. The tear strength was 1.8N in the longitudinal direction and 1.4N in the lateral direction. The texture was grade 3.
Example 2 (impregnation processing)
143 g of aqueous polyurethane aqueous dispersion A2 and 167 g of urethane prepolymer-terminated isocyanate block aqueous dispersion B1 (mass ratio (solid content conversion) (A) :( B) = 50: 50), 7 g of triethylenediamine and 183 g of water were mixed. An artificial leather was obtained in the same manner as in Example 1 except that the prepared treatment liquid was used.
In the obtained artificial leather, a dense porous structure was formed as shown in a cross-sectional electron micrograph in FIG. The tear strength was 1.7N in the longitudinal direction and 1.4N in the lateral direction. The texture was grade 3.
Example 3 (impregnation processing)
143 g of aqueous polyurethane aqueous dispersion A3, 167 g of urethane prepolymer-terminated isocyanate block aqueous dispersion B1 (mass ratio (solid content conversion) (A) :( B) = 50: 50), 3 g of triethylamine, 7 g of triethylenediamine and water An artificial leather was obtained in the same manner as in Example 1 except that a treatment liquid prepared by mixing 183 g was used.
In the obtained artificial leather, a dense porous structure was formed. The tear strength was 2.2N in the longitudinal direction and 1.7N in the lateral direction. The texture was second grade.
Example 4 (impregnation processing)
143 g of aqueous polyurethane aqueous dispersion A4, 167 g of urethane prepolymer-terminated isocyanate block aqueous dispersion B1 (mass ratio (solid content conversion) (A) :( B) = 50: 50), 3 g of triethylamine, 7 g of triethylenediamine and water An artificial leather was obtained in the same manner as in Example 1 except that a treatment liquid prepared by mixing 183 g was used.
In the obtained artificial leather, a dense porous structure was formed. The tear strength was 2.2N in the longitudinal direction and 1.7N in the lateral direction. The texture was second grade.
Example 5 (impregnation processing)
143 g of aqueous polyurethane aqueous dispersion A2 and 167 g of urethane prepolymer-terminated isocyanate block aqueous dispersion B2 (mass ratio (solid content conversion) (A) :( B) = 50: 50), 7 g of triethylenediamine and 183 g of water were mixed. An artificial leather was obtained in the same manner as in Example 1 except that the prepared treatment liquid was used.
In the obtained artificial leather, a dense porous structure was formed. The tear strength was 1.8N in the longitudinal direction and 1.4N in the lateral direction. The texture was grade 3.
Example 6 (impregnation processing)
143 g of aqueous polyurethane aqueous dispersion A2 and 167 g of urethane prepolymer-terminated isocyanate block aqueous dispersion B3 (mass ratio (solid content conversion) (A) :( B) = 50: 50), 7 g of triethylenediamine and 183 g of water were mixed. An artificial leather was obtained in the same manner as in Example 1 except that the prepared treatment liquid was used.
In the obtained artificial leather, a dense porous structure was formed. The tear strength was 1.8N in the longitudinal direction and 1.4N in the lateral direction. The texture was grade 3.
Example 7 (impregnation processing)
143 g of aqueous polyurethane aqueous dispersion A2 and 167 g of urethane prepolymer-terminated isocyanate block aqueous dispersion B4 (mass ratio (solid content conversion) (A) :( B) = 50: 50), 7 g of triethylenediamine and 183 g of water were mixed. An artificial leather was obtained in the same manner as in Example 1 except that the prepared treatment liquid was used.
In the obtained artificial leather, a dense porous structure was formed. The tear strength was 1.7 N in the vertical direction and 1.3 N in the horizontal direction. The texture was grade 3.
Example 8 (impregnation processing)
143 g of aqueous polyurethane aqueous dispersion A2 and 167 g of urethane prepolymer-terminated isocyanate block aqueous dispersion B6 (mass ratio (solid content conversion) (A) :( B) = 50: 50), 7 g of triethylenediamine and 183 g of water were mixed. An artificial leather was obtained in the same manner as in Example 1 except that the prepared treatment liquid was used.
In the obtained artificial leather, a dense porous structure was formed. The tear strength was 1.8N in the longitudinal direction and 1.3N in the lateral direction. The texture was grade 3.
Example 9 (impregnation processing)
57 g of aqueous polyurethane aqueous dispersion A2, 267 g of urethane prepolymer-terminated isocyanate block aqueous dispersion B1 (mass ratio (solid content conversion) (A) :( B) = 20: 80), 7 g of triethylenediamine and 169 g of water were mixed. An artificial leather was obtained in the same manner as in Example 1 except that the prepared treatment liquid was used.
In the obtained artificial leather, a dense porous structure was formed. The tear strength was 1.6 N in the vertical direction and 1.1 N in the horizontal direction. The texture was grade 4.
Example 10 (impregnation processing)
229 g of aqueous polyurethane aqueous dispersion A2 and 67 g of urethane prepolymer-terminated isocyanate block aqueous dispersion B1 (mass ratio (solid content conversion) (A) :( B) = 80: 20), 7 g of triethylenediamine and 197 g of water were mixed. An artificial leather was obtained in the same manner as in Example 1 except that the prepared treatment liquid was used.
In the obtained artificial leather, a dense porous structure was formed. The tear strength was 1.6N in the longitudinal direction and 1.2N in the lateral direction. The texture was grade 3.

Comparative Example 1 (impregnation processing)
Polyester nonwoven fabric having a fiber thickness of 1.0 denier and a density of 0.40 g / cm ³ , solvent-based polyurethane [Nikka Chemical Co., Ltd., Evaphanol ALS-30TD, dimethylformamide solution, solid content 30% by mass] 200 g and dimethylformamide The treatment liquid prepared by mixing 100 g was subjected to pad treatment with 330% by mass of the pickup. The work cloth after the pad treatment was immersed in a water bath for 5 minutes, and then washed with water at 80 ° C. for 5 minutes. Then, it was squeezed with a mangle and dried with a pin tenter adjusted to 120 ° C. to obtain artificial leather.
In the obtained artificial leather, a dense porous structure was formed. The tear strength was 1.8N in the longitudinal direction and 1.3N in the lateral direction. The texture was grade 3.
Comparative Example 2 (impregnation processing)
143 g of aqueous polyurethane aqueous dispersion A2, 167 g of urethane prepolymer-terminated isocyanate block aqueous dispersion B1 (mass ratio (solid content conversion) (A): (B) = 50: 50) and 190 g of water were mixed to prepare a mixture. An artificial leather was obtained in the same manner as in Example 1 except that the treated liquid was used.
In the obtained artificial leather, a porous structure was not formed. The tear strength was 0.9N in the longitudinal direction and 0.7N in the lateral direction. The texture was grade 5.
Comparative Example 3 (impregnation processing)
143 g of aqueous polyurethane aqueous dispersion A2 and 167 g of urethane prepolymer-terminated isocyanate block aqueous dispersion B5 (mass ratio (solid content conversion) (A) :( B) = 50: 50), 7 g of triethylenediamine and 183 g of water were mixed. An artificial leather was obtained in the same manner as in Example 1 except that the prepared treatment liquid was used.
In the obtained artificial leather, a porous structure was not formed as shown in an electron micrograph of a cross section in FIG. The tear strength was 2.5N in the longitudinal direction and 2.0N in the lateral direction. The texture was first grade.
Comparative Example 4 (impregnation processing)
143 g of aqueous polyurethane aqueous dispersion A2 and 167 g of urethane prepolymer-terminated isocyanate block aqueous dispersion B7 (mass ratio (solid content conversion) (A) :( B) = 50: 50), 7 g of triethylenediamine and 183 g of water were mixed. An artificial leather was obtained in the same manner as in Example 1 except that the prepared treatment liquid was used.
In the obtained artificial leather, a porous structure was partially formed. The tear strength was 1.3N in the vertical direction and 1.1N in the horizontal direction. The texture was grade 3.
The results of Examples 1 to 10 and Comparative Examples 1 to 4 are shown in Table 2.

As can be seen in Table 2, urethane prepolymer-terminated isocyanate block aqueous dispersion having 19.9 to 30.4% by mass of structural units composed of polyoxyethylene groups having an average molecular weight of 200 to 1,800 in the molecular skeleton In any of the artificial leathers of Examples 1 to 10 using the above, a dense porous structure is formed. The artificial leathers of Examples 1 to 8 have performances comparable to the artificial leather using the solvent-based polyurethane of Comparative Example 1 in both tear strength and texture. The artificial leather of Example 9 or Example 10 in which the resin mass ratio (in terms of solid content) is (A) :( B) = 20: 80 or (A) :( B) = 80: 20 has a tear strength. Although it is slightly lower than the artificial leathers of Examples 1 to 8, the texture is good.
On the other hand, in the artificial leather of Comparative Example 2 in which (C) the tertiary amine for promoting polymerization was not used, the resin did not remain in the nonwoven fabric, and no porous structure was formed. In the artificial leather of Comparative Example 3 in which the average molecular weight of the polyoxyethylene group in the structural unit of the urethane prepolymer-terminated isocyanate block aqueous dispersion is 2500, there is no formation of a porous structure, and a non-porous membrane resin is adhered. ing. Therefore, the texture is also coarse. In the artificial leather of Comparative Example 4 in which the amount of the polyoxyethylene group in the molecular weight skeleton of the structural unit of the urethane prepolymer-terminated isocyanate block aqueous dispersion is 50.6% by mass, formation of a porous structure is seen in part. However, the amount of resin falling off was large, the amount of resin adhering to the nonwoven fabric was small, and the tear strength was also reduced.
Example 11 (coating process)
Fluorine-based water repellent [Nikka Chemical Co., Ltd., NK Guard NDN-7E] impregnated in 0.5% by mass aqueous solution, squeezed with mangle, dried at 130 ° C for 1 minute, and subjected to weak water repellent finish On the fabric, 143 g of aqueous polyurethane aqueous dispersion A1 and 167 g of urethane prepolymer-terminated isocyanate block aqueous dispersion B1 (mass ratio (solid content conversion) (A): (B) = 50: 50), 7 g of triethylenediamine, A treatment liquid prepared by mixing 183 g of water and 2 g of a nonionic thickener [Nika Kagaku Co., Ltd., Neosticker N, solid content 30% by mass] and adjusting the viscosity to 3,000 mPa · s is 250 μm in slit thickness. After coating, the substrate was dried with dry heat at a temperature of 80 ° C. for 30 minutes. Subsequently, it was washed with water for 2 minutes, squeezed with a mangle, and dried with a dryer adjusted to 120 ° C. to obtain a synthetic leather.
A dense porous structure was formed in the polyurethane layer of the obtained synthetic leather as shown in a cross-sectional electron micrograph in FIG.
Comparative Example 5 (coating process)
Fluorine-based water repellent [Nikka Chemical Co., Ltd., NK Guard NDN-7E] impregnated in 0.5% by mass aqueous solution, squeezed with mangle, dried at 130 ° C. for 1 minute, and subjected to weak water repellent finish On the fabric, 143 g of aqueous polyurethane aqueous dispersion A1 and 167 g of urethane prepolymer-terminated isocyanate block aqueous dispersion B5 (mass ratio (solid content conversion) (A): (B) = 50: 50), 7 g of triethylenediamine, A treatment liquid prepared by mixing 183 g of water and 2 g of a nonionic thickener [Nika Kagaku Co., Ltd., Neosticker N, solid content 30% by mass] and adjusting the viscosity to 3,000 mPa · s is 250 μm in slit thickness. After coating, the substrate was dried with dry heat at a temperature of 80 ° C. for 30 minutes. Subsequently, it was washed with water for 2 minutes, squeezed with a mangle, and dried with a dryer adjusted to 120 ° C. to obtain a synthetic leather.
The polyurethane layer of the obtained synthetic leather was a nonporous film as shown in a cross-sectional electron micrograph in FIG.

  The artificial leather or synthetic leather obtained by the method for producing a porous structure of the present invention is comparable to the artificial leather or synthetic leather obtained from the conventional solvent-based polyurethane, and has no inferiority in performance such as strength and texture. It is possible to replace the polyurethane with an aqueous polyurethane. Accordingly, it is possible to reduce problems such as air pollution and water pollution caused by the solvent discharged during processing, the labor of collecting the solvent, and the working environment of the worker.

4 is an electron micrograph in place of a drawing showing a cross section of the artificial leather obtained in Example 2. FIG. 6 is an electron micrograph in place of a drawing showing a cross section of the artificial leather obtained in Comparative Example 3. It is an electron micrograph replaced with drawing which shows the cross section of the polyurethane layer of the synthetic leather obtained in Example 11. FIG. 6 is an electron micrograph in place of a drawing showing a cross section of a polyurethane layer of a synthetic leather obtained in Comparative Example 5.

Claims (8)

  (A) an aqueous polyurethane aqueous dispersion, (B) a urethane prepolymer-terminated isocyanate block aqueous dispersion having 10 to 40% by mass of structural units composed of polyoxyethylene groups having an average molecular weight of 100 to 2,000 in the molecular skeleton, and (C) The manufacturing method of the porous structure characterized by drying after dry heat drying or wet heat heating, after giving the liquid mixture containing a tertiary amine to a base material.   (A) An aqueous polyurethane aqueous dispersion is prepared by reacting an isocyanate group-terminated prepolymer obtained by reacting (a) a polyol compound and (b) a polyisocyanate compound with a nonionic surfactant having an HLB of 7 to 16. The porous structure according to claim 1, which is an aqueous polyurethane aqueous dispersion obtained by (c) chain extension reaction with a polyamine compound having two or more amino groups and / or imino groups after being dispersed in Method.   (A) An aqueous polyurethane water dispersion is an isocyanate group-terminated prepolymer obtained by reacting (a) a polyol compound, (b) a polyisocyanate compound and (c) a chain extender. The aqueous polyurethane aqueous dispersion obtained by dispersing in water using a surfactant and then subjecting it to a chain extension reaction with (d) a polyamine compound having two or more amino groups and / or imino groups. A method for producing a porous structure.   (A) A neutralized product of an isocyanate group-terminated prepolymer obtained by reacting an aqueous polyurethane aqueous dispersion with (a) a polyol compound, (b) a polyisocyanate compound, and (e) a compound that imparts an ionic hydrophilic group. The aqueous porous polyurethane dispersion according to claim 1, which is an aqueous polyurethane aqueous dispersion obtained by chain extension reaction with a polyamine compound having two or more amino groups and / or imino groups after being dispersed in water. Production method.   (A) An aqueous polyurethane aqueous dispersion is obtained by reacting (a) a polyol compound, (b) a polyisocyanate compound, (e) a compound imparting an ionic hydrophilic group, and (c) a chain extender. The aqueous polyurethane aqueous dispersion obtained by dispersing a neutralized product of a prepolymer in water and then subjecting it to a chain extension reaction with (d) a polyamine compound having two or more amino groups and / or imino groups. The manufacturing method of the porous structure of description.   (A) Aqueous polyurethane aqueous dispersion and (B) urethane prepolymer-terminated isocyanate block aqueous dispersion having 10 to 40% by mass of structural units composed of polyoxyethylene groups having an average molecular weight of 100 to 2,000 in the molecular skeleton. The method for producing a porous structure according to claim 1, wherein the mass ratio is (A) :( B) = 10: 90 to 90:10 in terms of solid content.   An artificial leather obtained by the method for producing a porous structure according to any one of claims 1 to 6. A synthetic leather obtained by the method for producing a porous structure according to any one of claims 1 to 6.