KR20200078345A - Method for producing leather material - Google Patents

Abstract

The present invention provides a method for manufacturing a leather solvent which can more easily and efficiently obtain the leather solvent having excellent soft feel than before. More specifically, the present invention relates to a method for manufacturing the leather solvent which obtains the leather solvent by impregnating a mixed liquor containing (A) water-based polyurethane resin, (B) a foaming agent which generates carbon acid gas by heating and/or acid, (C) a formic acid ester compound, and (D) water, followed by heating and drying the same.

Description

Manufacturing method for leather materials{METHOD FOR PRODUCING LEATHER MATERIAL}

The present invention relates to a method for producing a leather material, and more particularly, to a method for producing a leather material that can be suitably used as artificial leather or synthetic leather using an aqueous polyurethane resin.

Conventionally, as a substitute for natural leather, various artificial leathers and synthetic leathers made of a polyurethane resin and a fiber base have been manufactured. Such artificial leather or synthetic leather is obtained by imparting an organic solvent solution of a polyurethane resin to a fiber substrate by impregnation or application, for example, as a poor solvent for the polyurethane resin and compatible with the organic solvent. It was produced by a method called a wet coagulation method in which solidification is performed by passing through a solid solution (usually water), followed by washing with water and drying.

However, many organic solvents such as dimethylformamide, which are widely used in the wet coagulation method, have high flammability and toxicity, and therefore, there is a risk of fire, deterioration of the working environment, problems of environmental pollution such as air or water, and human health. Impact became a problem. For this reason, studies have been made to shift the polyurethane resin adhering to the fiber base material from an organic solvent type to an aqueous polyurethane resin.

For example, in Japanese Patent Laid-Open No. 2003-138131 (Patent Document 1), the aqueous properties of a carboxylate-type polyurethane resin containing a nonionic surfactant (nonionic surfactant) of HLB10 to 18 and an inorganic salt are described. Disclosed is a method of manufacturing a sheet material for leather, which is obtained by subjecting a dispersion to a fibrous base material and thermally solidifying it. However, in such a method, due to the influence of the surfactant and the inorganic salt, a processing problem that stability of the treatment bath deteriorates depending on the concentration of the inorganic salt to be blended, and a nonionic surfactant or inorganic salt remains in the fiber substrate. Therefore, there was a problem that the texture of the obtained leather material became rough and hard.

In addition, for example, in Japanese Patent Laid-Open No. 2002-249985 (Patent Document 2), a thermoplastic binder aqueous solution such as a polyurethane-based resin, an inorganic compound, a water-soluble organic polymer, a poorly water-soluble organic polymer, and a high cloud point surfactant Disclosed is a method for producing a porous structure in which a mixture solution of at least one selected from the group consisting of is applied to a substrate and dried after heating by moist heat with steam, and according to such a method, the texture of natural leather is expressed. It is possible to do. However, even in such a porous structure, there is a problem that the flexibility of the texture is not yet sufficient.

Further, in recent years, a method of adding a foaming agent and a heat-sensitive coagulant (thermal gelling agent) to an aqueous polyurethane resin and impregnating it with a fiber substrate to dry it has been studied. For example, in International Publication No. 2013/065608 (Patent Document 3), a process for imparting an aqueous dispersion-type polyurethane liquid (aqueous polyurethane resin) containing a blowing agent to a fiber substrate comprising ultrafine fiber-expressing fibers. A method of manufacturing a sheet-like article comprising a substrate is described, the water-dispersion-type polyurethane liquid is foamed after being heated, and the obtained water-dispersion-type polyurethane is made into a porous structure, so that the texture of the sheet-like article containing the polyurethane becomes flexible. It is described. However, in general, it is difficult to balance the foaming temperature of the foaming agent that generates carbon dioxide by heating and the solidification temperature of the polyurethane solution, and it is difficult to obtain a safe and uniform foam structure. It had a problem that it was difficult to easily obtain the product with high efficiency. In addition, even when drying conditions are relatively insufficient, such as low drying temperature or short drying time, the internal temperature of the fiber base material does not reach the foaming temperature during drying, or it takes a long time to reach the foaming temperature. The foaming is insufficient due to factors such as that it is required, and there is a problem that it is difficult to easily obtain a high-efficiency leather material excellent in flexible texture.

Japanese Patent Publication No. 2003-138131 Japanese Patent Publication No. 2002-249985 International Publication No. 2013/065608

This invention is made|formed in view of the subject which the said prior art has, and it aims at providing the manufacturing method of the leather material which can obtain the leather material excellent in the flexible texture more easily and efficiently.

The present inventors, as a result of repeated studies in order to achieve the above object, the aqueous polyurethane resin, a foaming agent for generating carbon dioxide gas by heating and/or acid, a formic acid ester compound, and a mixed solution containing water, By impregnating the fibrous base material with heat and drying, it has been found that a leather material having excellent flexible texture can be obtained more efficiently and efficiently without strict control of conditions and the like as in a conventional manufacturing method, and the present invention has been completed. .

That is, the manufacturing method of the leather material of this invention is as follows.

[1] The fiber substrate is impregnated with a mixed liquid containing (A) an aqueous polyurethane resin, (B) a blowing agent that generates carbon dioxide gas by heating and/or acid, (C) a formic acid ester compound, and (D) water. The method of manufacturing a leather material is obtained by subjecting it to heat drying after drying to obtain a leather material.

[2] The method for producing a leather material according to [1], wherein the foaming agent (B) is a carbonate.

[3] In the mixed solution, the mixing ratio (A:B:C) of the (A) water-based polyurethane resin, the (B) blowing agent and the (C) formic acid ester compound is 100:1 to 50:1 in mass ratio. To 75, the method for producing a leather material according to [1] or [2].

[4] The method for producing a leather material according to any one of [1] to [3], wherein the mixed solution further contains (E) a thickener.

[5] The method for producing a leather material according to any one of [1] to [4], wherein the mixed solution further contains (F) a heat sensitive gelling agent.

[6] [1] to [5], wherein the aqueous polyurethane resin (A) is a polyurethane resin having at least one anionic group selected from the group consisting of carboxyl groups, carboxylate groups, sulfo groups, and sulfonate groups. The manufacturing method of the leather material according to any one of the above.

[7] The method for producing a leather material according to any one of [1] to [6], wherein the mixture has a thermal solidification temperature of 30 to 80°C.

[8] Any of [1] to [7], wherein the mixture is impregnated with the fiber base material so that the component derived from the aqueous polyurethane resin (A) adheres to 10% of the central portion occupying the thickness of the leather material. The manufacturing method of the leather material described in one.

In addition, the reason why the leather material having excellent flexible texture can be more efficiently and efficiently obtained by the method for manufacturing the leather material of the present invention is not necessarily certain, but the present inventors estimate as follows. That is, in a method of drying after impregnating a fiber substrate with a mixture solution containing an aqueous polyurethane resin and a blowing agent, for example, foaming the blowing agent using only an acid-generating material to generate carbon dioxide gas, foaming The timing of is too fast, and on the other hand, as a method of generating the carbon dioxide gas by foaming the foaming agent only by heating, it is difficult to obtain a uniform foam structure because the timing of foaming is too slow. On the other hand, in the method for producing a leather material of the present invention, a formic acid ester compound is further contained in a mixed solution containing an aqueous polyurethane resin and a foaming agent that generates carbon dioxide gas by heating and/or acid. As the temperature gradually decomposes as the temperature rises, the pH gradually decreases as the temperature rises, and it becomes possible to generate carbon dioxide gas from the blowing agent at a timing at which a uniform foam structure can be obtained. The present inventors estimate that can be easily and efficiently obtained.

ADVANTAGE OF THE INVENTION According to this invention, it becomes possible to provide the manufacturing method of the leather material which can easily and efficiently obtain the leather material which is excellent in a flexible texture than before.

Hereinafter, this invention is demonstrated in detail based on the suitable embodiment.

The method for producing a leather material of the present invention comprises (A) an aqueous polyurethane resin, (B) a blowing agent that generates carbon dioxide gas by heating and/or acid, (C) a formic acid ester compound, and (D) water. It is characterized in that a mixture solution is impregnated with a fiber base material and then heated and dried to obtain a leather material.

(A) Water-based polyurethane resin

It is preferable that it is at least 1 sort(s) selected from the group which consists of the self-emulsifying type aqueous polyurethane resin which has a hydrophilic functional group, and a forced emulsifying type aqueous polyurethane resin as (A) aqueous polyurethane resin which concerns on this invention.

<Self-emulsifying type aqueous polyurethane resin>

In the present invention, the self-emulsifying aqueous polyurethane resin is an aqueous polyurethane resin having an anionic group in the resin skeleton. In the present invention, the self-emulsifying aqueous polyurethane resin is preferably a polyurethane resin in which separation or sedimentation is not observed even if the oil-in-water dispersion having a water concentration of 40% by weight of the polyurethane resin is left at 20°C for 12 hours. Do.

Examples of the anionic group include a carboxyl group, a carboxylate group, a sulfo group, and a sulfonate group. The self-emulsifying water-based polyurethane resin according to the present invention has at least one anionic group selected from the group consisting of carboxyl groups, carboxylate groups, sulfo groups, and sulfonate groups, from the viewpoint of excellent emulsion dispersion stability. It is preferably a polyurethane resin, and more preferably a polyurethane resin having a carboxyl group and/or a carboxylate group, or a polyurethane resin having a sulfo group and/or a sulfonate group.

The content of the anionic group in the self-emulsifying aqueous polyurethane resin is preferably 0.1 to 5.0% by mass, more preferably 0.2 to 2.5% by mass. Further, (i) when the self-emulsifying aqueous polyurethane resin according to the present invention has a carboxyl group and/or a carboxylate group, it is more preferable that the total content of the carboxyl group and the carboxylate group is 0.5 to 4.0 mass%, It is still more preferable that it is 0.7 to 2.5 mass %. Further, (ii) When the self-emulsifying aqueous polyurethane resin according to the present invention has a sulfo group and/or sulfonate group, it is more preferable that the total content of the sulfo group and the sulfonate group is 0.1 to 1.0 mass%, It is still more preferable that it is 0.2 to 1.0 mass %. In addition, (iii) When the self-emulsifying aqueous polyurethane resin according to the present invention has a carboxyl group and/or carboxylate group, and a sulfo group and/or sulfonate group, the total content of the carboxyl group and carboxylate group is 0.1. It is particularly preferable that the total content of the sulfo group and the sulfonate group is from 0.1 to 1.0% by mass.

When the content of the anionic group is less than the lower limit, the storage stability of the aqueous dispersion of the self-emulsifying aqueous polyurethane resin tends to deteriorate. On the other hand, when it exceeds the upper limit, the thermal solidification temperature of the obtained mixed solution Tends to be high, and the effect of suppressing the migration of leather materials (a phenomenon in which the aqueous polyurethane resin migrates to the surface of the fibrous base material) tends to decrease.

Moreover, in this invention, as a value of 100% modulus of the said self-emulsifying type aqueous polyurethane resin, it is preferable that it is 0.5 to 25 Mpa, and it is more preferable that it is 1 to 20 Mpa. When the value of 100% modulus is less than the above lower limit, it is possible to obtain a leather material having a flexible texture, but the wear resistance tends to be lowered. On the other hand, when the value exceeds the upper limit, the texture of the resulting leather material is reduced. There is a tendency to become hard, fluffing, or fibers to be liable to occur. In addition, in the present invention, the value of 100% modulus is measured using a dumbbell-shaped test piece No. 3, as in JIS K 6251 (2010), and when the distance between the marked lines is stretched by 100% (when doubled) It is the value of the predetermined elongation tensile stress in (kPa).

Examples of the self-emulsifying water-based polyurethane resin include,

(I) (a) an organic polyisocyanate, (b) a polyol and (c) an isocyanate group terminal prepolymer neutralized product having a carboxylate group obtained by reacting a carboxyl group with a compound having two or more active hydrogens is watered by self-emulsification. And (d) a polyurethane resin having a carboxyl group and/or a carboxylate group obtained by chain extension reaction using a polyamine compound having two or more amino groups and/or imino groups, and/or

(II) (a) an organic polyisocyanate, (b) a polyol and (e) an isocyanate group terminal having a sulfonate group obtained by reacting at least two amino and/or imino groups with a polyamine compound having a sulfo group and/or a sulfonate group Polyurethane having a sulfo group and/or a sulfonate group obtained by emulsifying and dispersing a prepolymer neutralization agent in water by self-emulsification and (d) a chain extension reaction using a polyamine compound having two or more amino groups and/or imino groups. Suzy,

Can be suitably used. Hereinafter, as a method for producing the self-emulsifying aqueous polyurethane resin, these resins will be described as an example.

(I) Polyurethane resin having carboxyl group and/or carboxylate group

(a) Organic polyisocyanate

The organic polyisocyanate is not particularly limited, and aliphatic polyisocyanates having two or more isocyanate groups, alicyclic polyisocyanates, and aromatic polyisocyanates can be used. Examples of the organic polyisocyanate include aliphatic diisocyanate compounds such as hexamethylene diisocyanate and trimethyl hexamethylene diisocyanate; Alicyclic diisocyanate compounds such as isophorone diisocyanate, hydrogenated xylylene diisocyanate, dicyclohexylmethane diisocyanate, norbornane diisocyanate, and 1,3-bis(isocyanatomethyl)cyclohexane; And aromatic diisocyanate compounds such as tolylene diisocyanate, diphenylmethane diisocyanate, naphthalene diisocyanate, tolidine diisocyanate, xylylene diisocyanate, and tetramethylxylylene diisocyanate. These polyisocyanate compounds may be used alone or in combination of two or more.

Among these organic polyisocyanates, the aliphatic diisocyanate compound and the alicyclic diisocyanate compound can be suitably used because they impart sulfur-free modification to the leather material, especially hexamethylene diisocyanate, isophorone diisocyanate, dicyclohexylmethane diisocyanate, Norbornane diisocyanate and 1,3-bis(isocyanatomethyl)cyclohexane can be suitably used.

(b) polyol

The polyol is not particularly limited as long as it has two or more hydroxy groups (however, (c) carboxyl groups and compounds having two or more active hydrogens are excluded), polyester polyols, polycarbonate polyols, polyether polyols, etc. Besides, a polyether ester polyol having an ether bond and an ester bond, a silicone polyol, or a fluorine polyol can also be used.

Examples of the polyester polyol include polyethylene adipate diol, polybutylene adipate diol, polyethylene butylene adipate diol, polyhexamethylene isophthalate adipate diol, polyethylene succinatediol, polybutylene succinate diol, polyethylene Sebacate diol, polybutylene sebacate diol, poly-ε-caprolactone diol, poly(3-methyl-1,5-pentylene) adipate diol, polycondensate of 1,6-hexanediol and dimer acid, 1 And copolymers of 6-hexanediol, adipic acid and dimer acid, polycondensates of nonandiol and dimer acid, and copolymers of ethylene glycol, adipic acid and dimer acid.

Examples of the polycarbonate polyol include polytetramethylene carbonate diol, polyhexamethylene carbonate diol, poly-1,4-cyclohexanedimethylene carbonate diol, and 1,6-hexanediol polycar And carbonate polyols.

As said polyether polyol, For example, the ethylene oxide, propylene oxide, butylene oxide, trimethylene oxide, and tetramethylene oxide, etc. C2-C4 alkylene oxide single addition polymerization or diol which is a study polymerization; And polyols in which alkylene oxides having 2 to 4 carbon atoms are randomly or blockly added to polyhydric alcohols such as glycerin and trimethylolpropane.

Examples of the silicone polyol include those in which two or more organic groups having a hydroxy group and/or a hydroxy group are introduced into the terminal and/or side chain of dimethylpolysiloxane, for example, carbinol-modified silicone oil, polyether-modified silicone oil, and sila Gnole terminal silicone oil is mentioned.

Examples of the fluorine polyol include polyols containing fluorine in the molecule, for example, Zeppel GK510, GK570 (above, manufactured by Daikin High School), Lumiflon LF200, LF400 (above, Asahi Garas Co., Ltd.) And).

These polyols may be used alone or in combination of two or more. Moreover, as a weight average molecular weight of such a polyol, it is preferable that it is 500-5,000, and it is more preferable that it is 1,000-3,000. Moreover, it is preferable to use polycarbonate polyol and/or polyether polyol as said polyol from a viewpoint that sufficient durability can be provided to a leather solvent by the obtained polyurethane resin. Moreover, it is preferable to use a silicone polyol and/or a fluorine polyol from a viewpoint that the texture of the obtained leather material tends to improve more.

(c) a compound having a carboxyl group and two or more active hydrogens

Examples of the compound having a carboxyl group and two or more active hydrogens include 2,2-dimethylolpropionic acid and 2,2-dimethylolbutanoic acid. Further, as the compound, a polyester polyol having a pendant carboxy group obtained by reacting a diol having a carboxy group with an aromatic dicarboxylic acid, an aliphatic dicarboxylic acid, or the like can also be used. Moreover, the compound which has such a carboxy group and two or more active hydrogens may be used individually by 1 type, or may be used in combination of 2 or more type.

(d) a polyamine compound having two or more amino groups and/or imino groups

As a polyamine compound having two or more amino groups and/or imino groups, for example, ethylenediamine, propylenediamine, tetramethylenediamine, hexamethylenediamine, diaminocyclohexylmethane, piperazine, hydrazine, 2-methylpiperazine, iso Diamines such as forondiamine, norbornanediamine, diaminodiphenylmethane, tolylenediamine, and xylylenediamine; Polyamines such as diethylenetriamine, triethylenetetramine, tetraethylenepentamine, iminobispropylamine, and tris(2-aminoethyl)amine; Amideamines derived from di-primary amines and monocarboxylic acids; Water-soluble amine derivatives such as monoketimine of the di-primary amine; Dihydrazide oxalate, dihydrazide malonate, dihydrazide succinate, dihydrazide glutaride, dihydrazide adipic acid, dihydrazide sebacate, dihydrazide maleate, dihydrazide fumarate, dihydrazide fumarate, dihydride itaconic acid 1 And hydrazine derivatives such as ,1'-ethylenehydrazine, 1,1'-trimethylenehydrazine, and 1,1'-(1,4-butylene)dihydrazine. The polyamine compound having two or more of these amino groups and/or imino groups may be used alone or in combination of two or more kinds.

The polyurethane resin having a carboxyl group and/or a carboxylate group (I) is a neutralized product of an isocyanate group terminal prepolymer having a carboxylate group (hereinafter referred to as ``CA isocyanate group terminal prepolymer neutralizer'' in some cases). It can be obtained as an emulsifying dispersion of the polyurethane resin by emulsifying and elongating reaction with water by emulsification.

An isocyanate-terminated prepolymer having a neutralized product, ^- the CA isocyanate-terminated prepolymer are neutralized product, (c) the carboxyl group and two carboxyl groups are neutralized with a carboxylate group (-COO) derived from a compound having at least one active hydrogen It is obtained by reacting the (a) organic polyisocyanate, the (b) polyol and the (c) carboxyl group with a compound having two or more active hydrogens.

The specific method for obtaining the CA isocyanate group terminal prepolymer neutralization is not particularly limited, and can be produced, for example, by a conventionally known one-step so-called one-shot method, a multi-stage isocyanate polyaddition reaction method or the like. The reaction temperature at this time is preferably 40 to 150°C.

In addition, in such a reaction, a low molecular weight chain extender having two or more active hydrogen atoms can be used, if necessary. As the low molecular weight chain extender, the molecular weight is preferably 400 or less, particularly preferably 300 or less. Further, as the low molecular weight chain extender, for example, low molecular weight polyvalents such as ethylene glycol, propylene glycol, neopentyl glycol, 1,4-butanediol, 1,6-hexanediol, trimethylolpropane, pentaerythritol, sorbitol, etc. Alcohol; And low molecular weight polyamines such as ethylenediamine, propylenediamine, hexamethylenediamine, diaminocyclohexylmethane, piperazine, 2-methylpiperazine, isophoronediamine, diethylenetriamine, and triethylenetetramine. Moreover, as said low molecular weight chain extender, 1 type may be used individually or may be used in combination of 2 or more type.

In addition, during the reaction, if necessary, reactions such as dibutyl tin dilaurate, stannous octoate, dibutyl tin-2-ethylhexanoate, triethylamine, triethylenediamine, and N-methylmorpholine Catalysts can be added. In addition, an organic solvent that does not react with an isocyanate group can be added at the time of the reaction or after the reaction. Examples of the organic solvent include acetone, methyl ethyl ketone, toluene, tetrahydrofuran, dioxane, dimethylformamide, N-methylpyrrolidone, ethyl acetate, and methyl isobutyl ketone.

The neutralization of the (c) carboxyl group and the carboxyl group derived from the compound having two or more active hydrogens may be performed simultaneously with the preparation of the isocyanate group terminal prepolymer, or before or after production. Such neutralization can be carried out using a method known as appropriate, and the compound used for such neutralization is not particularly limited, and for example, trimethylamine, triethylamine, tri-n-propylamine, tributylamine, N Amines such as -methyl-diethanolamine, N,N-dimethylmonoethanolamine, N,N-diethylmonoethanolamine, and triethanolamine; Potassium hydroxide; Sodium hydroxide; And ammonia. Among these, tertiary amines such as trimethylamine, triethylamine, tri-n-propylamine and tributylamine are particularly preferred.

The method for emulsifying and dispersing the CA isocyanate group terminated prepolymer neutralization agent in water is not particularly limited, and examples thereof include a method using an emulsifying device such as a homomixer, a homogenizer or a disper. In addition, when emulsifying and dispersing the CA isocyanate group terminal prepolymer neutralizer in water, the prepolymer neutralizer is emulsified and dispersed in water by self-emulsification at a temperature in the range of room temperature to 40°C without using an emulsifier. It is desirable to suppress the reaction with water as much as possible. In addition, when emulsifying and dispersing in this way, reaction inhibitors such as phosphoric acid, sodium dihydrogen phosphate, disodium hydrogen phosphate, paratoluenesulfonic acid, adipic acid, and benzoyl chloride can be added, if necessary.

In the chain extension reaction of the CA isocyanate group terminal prepolymer neutralization agent, a polyamine compound having two or more amino groups and/or imino groups (d) is added to the CA isocyanate group terminal prepolymer neutralization agent, or the (d) amino group. And/or to the polyamine compound having two or more imino groups, by adding the above CA isocyanate group terminal prepolymer neutralizer. It is preferable to perform such a chain extension reaction at reaction temperature of 20-40 degreeC, and it is usually completed in 30 to 120 minutes.

In the production method of the polyurethane resin having a carboxyl group and/or a carboxylate group (I), the emulsification dispersion and the chain extension reaction may be simultaneous, and the CA isocyanate group terminal prepolymer neutralization is emulsified and dispersed, followed by chain extension. It may be reacted or may be emulsified and dispersed after a chain extension reaction. In addition, when the above-mentioned organic solvent is used when preparing the CA isocyanate group terminal prepolymer neutralized product, it is preferable to remove the organic solvent by evaporation under reduced pressure or the like after, for example, a chain extension reaction or emulsion dispersion.

(II) Polyurethane resin having sulfo group and/or sulfonate group

(II) (a) an organic polyisocyanate, (b) a polyol and (d) a polyamine compound having two or more amino groups and/or imino groups used for the production of a polyurethane resin having a sulfo group and/or a sulfonate group, the above (I) The thing similar to what was illustrated in the manufacturing of the polyurethane resin which has a carboxyl group and/or a carboxylate group is mentioned.

(e) a polyamine compound having two or more amino and/or imino groups and a sulfo and/or sulfonate group

As a polyamine compound having two or more amino groups and/or imino groups and a sulfo group and/or sulfonate group, it is sufficient to have two or more amino groups and/or imino groups, and also to have a sulfo group and/or a sulfonate group, eg Examples include 2-(2-aminoethylamino)-ethanesulfonate, 2-(3-aminopropylamino)-ethanesulfonate, and 2,4-diaminobenzenesulfonate sodium. These compounds may be used alone or in combination of two or more.

The above-mentioned (II) polyurethane resin having a sulfo group and/or sulfonate group is self-emulsifying of an isocyanate group terminal prepolymer having a sulfonate group (hereinafter sometimes referred to as "SU isocyanate group terminal prepolymer neutralization"). It can be obtained as an emulsifying dispersion of the polyurethane resin by emulsifying and dispersing water into the water and by elongation reaction.

The SU isocyanate group terminal prepolymer neutralized product is a sulfonate group (-SO ₃ ) in which (e) the sulfo group derived from a polyamine compound having at least two amino groups and/or imino groups and sulfo groups and/or sulfonate groups is neutralized. ^- ) an isocyanate group terminated prepolymer neutralizer having (a) an organic polyisocyanate, (b) a polyol and (e) at least two amino groups and/or imino groups and a polyamine having a sulfo group and/or a sulfonate group It is obtained by reacting a compound.

The method for obtaining the SU isocyanate group terminated prepolymer neutralization is not particularly limited, and instead of (c) a carboxyl group and a compound having two or more active hydrogens, (e) two or more amino groups and/or imino groups; The method similar to the said CA isocyanate group terminal prepolymer neutralization can be mentioned except using the polyamine compound which has an aeration and/or sulfonate group. In addition, the method for obtaining the polyurethane resin having the (II) sulfo group and/or sulfonate group by emulsion dispersion and chain extension reaction of the SU isocyanate group terminal prepolymer neutralization agent is also used instead of the CA isocyanate group terminal prepolymer neutralization agent. The method similar to the method demonstrated in the manufacturing method of the polyurethane resin which has the said (I) carboxyl group and/or carboxylate group can be employ|adopted except using SU isocyanate group terminal prepolymer neutralization.

The self-emulsifying water-based polyurethane resin is usually obtained as a water-emulsifying dispersion of a resin, and distributed on the market, and may be used as appropriate. The self-emulsifying water-based polyurethane resin is preferably used in an emulsified and dispersed state in water, and the concentration is not particularly limited, but the mixture according to the present invention tends to be easily obtained in a uniform state. In addition, in consideration of the fixing amount of the resin component to the fiber substrate, it is preferably 15 to 60% by mass.

In addition, in the present invention, when the self-emulsifying water-based polyurethane resin and the following forced emulsifying water-based polyurethane resin are used while being emulsified and dispersed in water, (A) the mass of the water-based polyurethane resin (two or more water-based In the case of a mixture of polyurethane resins, their total mass) refers to the remainder (solid content, non-volatile content) when the water-based dispersion of the aqueous polyurethane resin is heated at a temperature of 105°C for 3 hours.

(Forced emulsifying type aqueous polyurethane resin)

In the present invention, the compulsory emulsifying aqueous polyurethane resin does not have the anionic group (sulfo group, sulfonate group, carboxyl group, carboxylate group, etc.), does not have self-emulsifying property, and emulsifies with water. In order to add an emulsifying agent (in the present invention, a surfactant is included), it is a water-based polyurethane resin of the type (forced emulsifying type) capable of forcibly emulsifying with the emulsifying agent. In the present invention, as the above-mentioned forced emulsifying type aqueous polyurethane resin, the aqueous emulsifying dispersion obtained by forcibly emulsifying using the emulsifier appropriately so that the concentration of the polyurethane resin in water is 40% by mass, is allowed to stand at 20°C for 12 hours. It is preferable that it is a polyurethane resin in which separation or sedimentation is not observed even if the island is separated.

As such a forced emulsifying type aqueous polyurethane resin, for example,

(III) An isocyanate group terminal prepolymer obtained by reacting (a) the organic polyisocyanate with the (b) polyol is emulsified and dispersed in water in the presence of an emulsifier, and (d) two amino groups and/or imino groups. Polyurethane resin obtained by carrying out a chain extension reaction using the above-mentioned polyamine compound

Can be suitably used. Hereinafter, as a manufacturing method of the said forced emulsion type aqueous polyurethane resin, it demonstrates taking such resin as an example.

When preparing the forced emulsifying type aqueous polyurethane resin, first, the (a) organic polyisocyanate and the (b) polyol are reacted to prepare an isocyanate group terminal prepolymer. The method for preparing such an isocyanate group terminated prepolymer is not particularly limited, and the compound (c) having a carboxyl group and two or more active hydrogens or the compound (e) two or more amino groups and/or imino groups and a sulfo group and/or Method similar to the method for obtaining the above-described CA isocyanate group terminal prepolymer neutralizer or SU isocyanate group terminal prepolymer neutralizer, except that the polyamine compound having a sulfonate group is not used, and there is no need to neutralize the carboxyl group or sulfo group. Can be employed.

When preparing the said forced emulsion type aqueous polyurethane resin, the obtained isocyanate group terminal prepolymer is then subjected to emulsion dispersion and chain extension reaction to obtain a forced emulsion type aqueous polyurethane resin. The method of emulsifying and dispersing the isocyanate group terminal prepolymer is not particularly limited, and the above isocyanate group terminal prepolymer is used instead of the above-described CA isocyanate group terminal prepolymer neutralizer or SU isocyanate group terminal prepolymer neutralizer, and The method similar to the method demonstrated in the manufacturing method of the said self-emulsifying type aqueous polyurethane resin can be employ|adopted except using the said emulsifier when emulsifying and dispersing. That is, instead of the above-described CA isocyanate group terminal prepolymer neutralization or SU isocyanate group terminal prepolymer neutralization, a urethane prepolymer having an isocyanate group at the terminal is used, and an emulsifier is used when emulsifying and dispersing the isocyanate group terminal prepolymer in water. , It is sufficient to carry out a chain extension reaction with emulsifying and dispersing. As a method for emulsifying and dispersing in water or a chain extension reaction, the same method as the emulsifying and dispersing method described in the method for producing the self-emulsifying water-based polyurethane resin or the chain extension reaction, respectively. Can be employed.

When manufacturing the said forced emulsifying type aqueous polyurethane resin, a nonionic surfactant and an anionic surfactant are mentioned as said emulsifier. As said nonionic surfactant, for example, polyoxyethylene distyrylphenyl ether type nonionic surfactant, polyoxyethylene propylene distyrylphenyl ether type nonionic surfactant, polyoxyethylene tristyrylphenyl ether type nonionic surfactant , Polyoxyethylene propylene tristyrylphenyl ether type nonionic surfactants, and pluronic type nonionic surfactants. Moreover, as said anionic surfactant, for example, higher alcohol sulfate ester salt, higher alkyl ether sulfate ester salt, polyalkylene glycol sulfate ester salt, polyoxyalkylene aryl ether sulfate ester salt, polyoxyalkylene aryl ether phosphate ester Hydrochloride sulfuric acid oil, sulfated fatty acid ester, alkylbenzene sulfonate, alkyl naphthalene sulfonate, naphthalene sulfonate and polymers thereof, paraffin sulfonate, dialkyl sulfosuccinate, polystyrene sulfonate, lignin sulfonate, alkyl ether phosphate salt Can be lifted.

As the emulsifier, one of these may be used alone or two or more of them may be used in combination, but it is preferable that it is at least one of the nonionic surfactants, and among them, an aqueous dispersion of a compulsory emulsifying aqueous polyurethane resin From the viewpoints of storage stability and processing stability, HLBs of 7 to 16 can be suitably used. In addition, in the present invention, the value of HLB is the following equation:

Molecular weight of oxyethylene group part in nonionic surfactant × 20/molecular weight of nonionic surfactant

It is a value obtained by.

The amount of the emulsifier added varies depending on the hydrophilicity resulting from the content of the polyoxyethylene group of the isocyanate group terminal prepolymer, which is an emulsified substance, and cannot be said uniformly, but is 0.5 to 10 parts by mass based on 100 parts by mass of the isocyanate group terminal prepolymer. It is preferable, and it is more preferable that it is 1 to 6 parts by mass. When the amount of the emulsifier added is less than the above lower limit, it tends to be difficult to obtain a sufficiently stable emulsion dispersion state. On the other hand, when the above-mentioned upper limit is exceeded, the water resistance of the resulting foam structure tends to decrease.

The above-mentioned forced emulsifying aqueous polyurethane resin can be obtained as an emulsifying dispersion of the polyurethane resin by emulsifying dispersion and chain extension reaction to water in the presence of an emulsifier of the isocyanate group terminal prepolymer. It is preferable to use such a forced emulsifying type aqueous polyurethane resin in an emulsified and dispersed state in water, and the concentration is not particularly limited, but the mixture according to the present invention tends to be easily obtained in a uniform state. In addition, in consideration of the fixing amount of the resin component to the fiber substrate, it is preferably 15 to 60% by mass.

(B) blowing agent

The foaming agent (B) according to the present invention is a foaming agent that generates carbon dioxide gas by heating, or by acid, or by heating and acid (by heating and/or acid). As the foaming agent (B) according to the present invention, it is preferably a thermal decomposition type chemical foaming agent, and more preferably a carbonate salt. As the foaming agent (B), one type may be used singly or two or more types may be used in combination, but among them, sodium carbonate, potassium carbonate, ammonium carbonate, and sodium hydrogen carbonate (medium sodium) from the viewpoint of processing stability of the mixed solution. It is preferably at least one carbonate selected from the group consisting of, potassium hydrogen carbonate, and ammonium hydrogen carbonate (ammonium bicarbonate).

In the present invention, the foaming agent (B) may be used as it is in a solid (powder) state, but from the viewpoint of maintaining the stability of the emulsion dispersion of the aqueous polyurethane resin (A), the foaming agent (B) is watered. It is preferably used in the form of an aqueous solution. The concentration of the aqueous solution of the above-mentioned (B) blowing agent is not particularly limited, and can be about 1 to 50% by mass.

(C) Formic acid ester compound

(C) Formic acid ester compound which concerns on this invention is a formic acid ester of a hydroxy compound. Examples of the hydroxy compound include lower alcohols having 1 to 4 carbon atoms, mono or polyalkylene glycol, trimethylolpropane, mono or polyglycerin, and one of these may be used alone or in combination of two or more. You may use it. Among them, the hydroxy compound is preferably a mono or polyalkylene glycol from the viewpoint of flexibility of the resulting leather solvent, and more preferably ethylene glycol, diethylene glycol, triethylene glycol, or polyethylene glycol having a polymerization degree of 3 to 10. It is preferable, and it is more preferable that it is ethylene glycol.

Further, as the formate ester compound (C) according to the present invention, orthoformate esters such as trimethyl orthoformate (trimethyl orthoformate) and triethyl orthoformate can also be used. As these formic acid ester compounds, one type may be used alone, or two or more types may be used in combination.

(D) water

(D) Water according to the present invention has a role as a solvent when mixing the (A) water-based polyurethane resin, the (B) blowing agent, the (C) formic acid ester compound, and each component described below as necessary. And ion-exchanged or distilled water can be suitably used.

In addition, as such (D) water, for example, when using the emulsion dispersion in which the above-mentioned (A) aqueous polyurethane resin is emulsified and dispersed, or when each component is used as an aqueous solution, the emulsion dispersion or the aqueous solution is used. You may use the water as it is as (D) water which concerns on this invention by using it as it is without distilling and removing water in it.

(E) Thickener

As the mixed liquid according to the present invention, it is preferable to further contain (E) a thickener. By further containing the above-mentioned (E) thickener, migration is suppressed, and the thickness of the fiber base material is sufficiently maintained, and it becomes possible to obtain a leather material excellent in a more flexible texture.

The (E) thickener is not particularly limited, and a known thickener capable of being used in the aqueous dispersion of an aqueous polyurethane resin can be suitably used, but at least one selected from the group consisting of an associative thickener and a water-soluble polymer thickener is particularly preferred. It is preferably a species.

Examples of the associative thickener include Japanese Patent Publication No. 54-80349, Japanese Patent Publication No. 58-213074, Japanese Patent Publication No. 60-49022, Japanese Patent Publication No. 52-25840, Japan Urethane-based associative thickeners described in Japanese Unexamined Patent Publication No. Hei 9-67563, Japanese Patent Publication No. Hei 9-71766, and the like; Associative thickeners obtained by copolymerizing nonionic urethane monomers described in Japanese Patent Laid-Open No. 62-292879, Japanese Patent Laid-Open No. Hei 10-121030 with other acrylic monomers as associative monomers; And an associative thickener having an aminoplast skeleton as described in WO9640815 and the like. Among these, as the above-mentioned associative thickener, it is preferable that the nonionic property is strong, and from the viewpoint of the density and strength retention of pores in the resulting foamed structure (porous structure), an association having a polyethylene glycol chain and a urethane bond in the molecular chain. Mold thickeners are more preferred. As such an associative thickener, for example, commercial products such as Neostacker S (manufactured by Nikka Chemical Co., Ltd.) and Visizer AP-2 (Sanyo Kasei High School Co., Ltd.) may be used as appropriate.

Examples of the water-soluble polymer thickener include cellulose-based derivatives such as methyl cellulose, ethyl cellulose, hydroxyethyl cellulose, hydroxypropyl cellulose, methylhydroxypropyl cellulose, and carboxymethyl cellulose; Starch-based derivatives such as soluble starch, carboxymethyl starch, and methyl starch; Alginic acid systems such as sodium alginate and propylene glycol alginate esters; Natural gums such as guar gum, carrageenan, galactan, gum arabic, locust bean gum, queen's seed, tragacanth gum, pectin, mannan, starch, xanthan gum, dextran, succino glucan, curdlan, hyaluronic acid and salts thereof Polysaccharide type; Natural protein systems such as casein, gelatin, collagen and albumin; Polyalkylene glycol, polyoxyethylene glycol distearic acid ester, myristoyl polyoxyethylene stearyl ether, polyoxyethylene sorbitan triisostearylate, polyoxyethylene methyl glucose (mono, di or tri) laurate, Polyoxyethylene methyl glucose (mono, di or tri) millistate, polyoxyethylene methyl glucose (mono, di or tri) palmitate, polyoxyethylene methyl glucose (mono, di or tri) stearate, polyoxyethylene methyl glucose Polyoxyalkylene-based nonionic polymers such as (mono, di or tri) isostearate and polyoxyethylene methyl glucose (mono, di or tri) oleate; And vinyl-based polymers such as polyvinyl alcohol, polyvinylpyrrolidone, and polyvinyl methyl ether, and mixtures thereof, and among these, nonionic properties are more preferable. As such a water-soluble polymer thickener, commercially available products such as HEC AX-15 (Sumitomo Seika Co., Ltd., hydroxyethyl cellulose), Kelzan (Sansho Co., Ltd., polymer polysaccharide (xanthan gum)) may be used as appropriate.

(F) Thermal gelling agent

As the mixed liquid according to the present invention, it is preferable to further contain (F) a heat-sensitive gelling agent from the viewpoint that the softening of the temporary layer of the texture is possible by suppressing shrinkage and migration of the foam structure during heat drying.

The (F) heat-sensitive gelling agent is not particularly limited, and a known heat-sensitive gelling agent (a conventional foam-forming composition containing a water-based polyurethane resin is used to heat-sensitize the composition (thermal coagulation). Known heat-sensitive gelling agents, etc.) can be appropriately used, and examples thereof include sodium salts of inorganic acids, ammonium salts of inorganic acids, and water-soluble acrylic polymers. One of these may be used alone or in combination of two or more. You may use

Examples of the inorganic acid in the sodium salt of the inorganic acid or the ammonium salt of the inorganic acid include perchloric acid, carbonic acid, sulfuric acid, persulfuric acid, sulfurous acid, phosphoric acid and nitric acid. Especially, sulfuric acid and phosphoric acid are preferable as the inorganic acid from the viewpoint of excellent migration suppression effect.

Examples of the sodium salt of the inorganic acid include sodium sulfate (forget-me-not). In addition, as the ammonium salt of the inorganic acid, for example, ammonium persulfate, ammonium perchlorate, ammonium carbonate, ammonium sulfate, ammonium hydrogen sulfate, ammonium sulfite, ammonium hydrogen sulfite, triammonium phosphate, diammonium hydrogen phosphate, ammonium dihydrogen phosphate, persulfate Ammonium, ammonium nitrate, ammonium chloride, etc. may be used, and one of them may be used alone or in combination of two or more, but it is easy due to the safety of handling, the problem of volatilization during drying, and washing after drying. From the viewpoint of being easily removed and remaining in the leather material, at least one selected from the group consisting of ammonium sulfate, diammonium hydrogen phosphate and ammonium dihydrogen phosphate can be suitably used. Moreover, when using ammonium dihydrogen phosphate as the ammonium salt of the said inorganic acid, it is more preferable to use it in combination with diammonium hydrogen phosphate.

The water-soluble acrylic polymer is not particularly limited, but is preferably at least one of the following components (1), (2), (3), (4) and (5).

[Ingredient (1)]

At least one of a polymer of at least one monomer selected from the group consisting of acrylic acid, methacrylic acid and maleic acid, an alkali metal salt of the polymer, and an amine salt of the polymer.

[Ingredient (2)]

At least one of poly-α-hydroxyacrylic acid, alkali metal salts of poly-α-hydroxyacrylic acid and amine salts of poly-α-hydroxyacrylic acid.

[Ingredient (3)]

Selected from the group consisting of acrylic acid, methacrylic acid, maleic acid, alkali metal salt of acrylic acid, alkali metal salt of methacrylic acid, alkali metal salt of maleic acid, amine salt of acrylic acid, amine salt of methacrylic acid and amine salt of maleic acid Obtained by radical polymerization of at least one monomer selected from the group consisting of poly-α-hydroxyacrylic acid, alkali metal salts of poly-α-hydroxyacrylic acid and amine salts of poly-α-hydroxyacrylic acid. At least one kind of a polymer, an alkali metal salt of the polymer, and an amine salt of the polymer.

[Ingredient (4)]

Acrylic acid, methacrylic acid, maleic acid, poly-α-hydroxyacrylic acid, alkali metal salt of acrylic acid, alkali metal salt of methacrylic acid, alkali metal salt of maleic acid, alkali metal salt of poly-α-hydroxyacrylic acid, amine salt of acrylic acid , At least one acrylic acid monomer selected from the group consisting of amine salts of methacrylic acid, amine salts of maleic acid and amine salts of poly-α-hydroxyacrylic acid, and 2-acrylamide-2-methylpropanesulfonic acid, At least one kind of a polymer obtained by radical polymerization of a sulfonic acid-based monomer such as styrene sulfonic acid and alkali metal and/or amine salts thereof.

[Ingredient (5)]

A polymerization product obtained by radically polymerizing an acrylic acid monomer and a nonionic monomer, and a polymerization product obtained by radical polymerization of a monomer mixture containing an acrylic acid monomer, a sulfonic acid monomer, and a nonionic monomer, and also an acrylic acid monomer and sulfonic acid in the monomer mixture. At least one of the polymers having a content (total amount) of 30% by mass or more with a system monomer.

Examples of the nonionic monomer in the component (5) include acrylic acid (1 to 22 carbon atoms) alkyl esters, vinyl acetate, styrene, α-methylstyrene, p-methylstyrene, glycidyl (meth)acrylate, and (meth) )Acrylamide, N,N-dimethyl (meth)acrylamide, diacetone (meth)acrylamide, methylolated diacetone (meth)acrylamide, N-methylol (meth)acrylamide, 3-chloro-2-hydride Hydroxypropyl (meth)acrylate, vinyl alkyl ether, halogenated alkyl vinyl ether, vinyl alkyl ketone, butadiene, isoprene, chloroprene, aziridinyl ethyl (meth)acrylate, aziridinyl (meth)acrylate, polyoxyalkylene (Meth)acrylate, methyl polyoxyalkylene (meth)acrylate, 2-ethylhexyl polyoxyalkylene (meth)acrylate, polyoxyalkylene di(meth)acrylate, triallyl cyanurate, allylglycine Diether, allyl acetate, N-vinylcarbazole, maleimide, N-methylmaleimide, (2-dimethylamino)ethyl (meth)acrylate, glycerol (meth)acrylate, alkylenedi(meth)acrylate, vinyl (Meth)acrylate having silicones such as silane and trimethoxysilyl (meth)acrylate on the side chain, (meth)acrylate having polysiloxane, (meth)acrylate containing blocked isocyanate groups, and (meth) having urethane bonds And acrylates.

Further, as the water-soluble acrylic polymer (preferably at least one of components (1) to (5)), for example, commercial products such as Aaron A-50P (made by Toa Kose Co., Ltd., sulfonic acid monomer copolymer type acrylic thickener) You may use suitably.

When the mixed liquid according to the present invention further contains the above-mentioned (F) heat-sensitive gelling agent, the (F) heat-sensitive gelling agent may be used as it is in a solid (powder) state, but (A) emulsification of the aqueous polyurethane resin. From the viewpoint of maintaining the stability of the dispersion, it is preferable to use the (F) heat-sensitive gelling agent in water and use it in the form of an aqueous solution. The concentration of the aqueous solution of the above-mentioned (F) heat-sensitive gelling agent is preferably 1 to 50% by mass, and more preferably 10 to 30% by mass. When the concentration becomes less than the lower limit, a large amount of the aqueous solution is required in order to exhibit migration inhibition during drying, and, consequently, the concentration of the aqueous polyurethane resin (A) in the mixed solution is lowered. Therefore, since a large amount of the mixed liquid is required to obtain the target leather material, the amount of water to be volatilized increases, the drying time tends to increase, and the economy tends to deteriorate. However, this problem tends to be improved by the method of the present invention being a method with high production efficiency. On the other hand, when the concentration exceeds the upper limit, there is a tendency to impair the stability of the emulsion dispersion, such as precipitates generated during mixing with the emulsion dispersion of the aqueous polyurethane resin (A).

<mixture>

In the method for producing a leather material of the present invention, the (A) water-based polyurethane resin, the (B) foaming agent, the (C) formic acid ester compound, the (D) water, and (E) the thickener if necessary, and / Or (F) to prepare a mixed solution containing a thermal gelling agent.

In the mixed solution according to the present invention, the content of the aqueous polyurethane resin (A) is preferably 5 to 50% by mass, more preferably 10 to 35% by mass relative to the total amount of the mixed solution. When the content of the aqueous polyurethane resin (A) is less than the lower limit, a large amount of the mixed liquid is required to obtain the target leather solvent, so the amount of water to be volatilized increases, the drying time becomes longer, and the tendency for economic efficiency to decrease have. On the other hand, when it exceeds the said upper limit, stability of the mixed liquid tends to fall.

In addition, in this invention, when it says content or compounding quantity, the value shows the total content or blending quantity of these components, when they are a mixture of 2 or more types.

In the mixed solution according to the present invention, the mixing ratio (A:B) of the (A) water-based polyurethane resin and the (B) blowing agent is preferably 100:1 to 50 by mass ratio, and 100:5 to 50 It is more preferable that it is 100, and it is still more preferable that it is 100:5-30. When the blending amount of the (B) blowing agent is less than the above lower limit, the effect of imparting a flexible texture to the resulting leather material tends to decrease, while when it exceeds the upper limit, the stability of the mixed solution over time tends to decrease. have. Moreover, even if it mix|blends the said (B) foaming agent exceeding the said upper limit, it will tend to not improve further, and it becomes economically unfavorable.

Moreover, in the mixed liquid which concerns on this invention, as a compounding quantity ratio (A:C) of said (A) aqueous polyurethane resin and said (C) formic acid ester compound, it is preferable that it is 100:1 to 75 by mass ratio, and it is 100. It is more preferable that it is :5 to 75, and it is still more preferable that it is 100:5 to 50. When the compounding amount of the (C) formic acid ester compound is less than the above lower limit, the effect of imparting a flexible texture to the resulting leather material tends to decrease, while when it exceeds the upper limit, the temperature is relatively high, such as in summer. Under the atmosphere, the mixed liquid tends to foam, or the stability of the mixed liquid over time tends to decrease. Moreover, even if it mix|blends a formic acid ester compound (C) exceeding the said upper limit, it will become unfavorable economically because performance will not improve further.

Moreover, in the mixed liquid which concerns on this invention, as a compounding quantity ratio (A:B:C) of the said (A) aqueous polyurethane resin, the said (B) foaming agent, and said (C) formic acid ester compound, it is the same viewpoint as above. , It is preferably from 100:1 to 50:1 to 75 by mass ratio, more preferably from 100:5 to 50:5 to 75, and even more preferably from 100:5 to 30:5 to 50.

Moreover, when the mixture liquid which concerns on this invention contains the said (E) thickener further, as a compounding quantity ratio (A:E) of the said (A) aqueous polyurethane resin and the said (E) thickener, it is 100:0.01 by mass ratio It is preferably 50, more preferably 100:0.1 to 30, and even more preferably 100:0.1 to 10. When the blending amount of the above-mentioned (E) thickener is less than the above lower limit, the effect of imparting a soft texture tends to be lowered by the obtained leather solvent. On the other hand, when it exceeds the upper limit, the mixed solution becomes high viscosity and the usability decreases. Tend to be.

In addition, when the mixture liquid according to the present invention further contains the (F) thermosensitive gelling agent, the mixing ratio (A:F) of the (A) water-based polyurethane resin and the (F) thermosensitive gelling agent is a mass ratio. It is preferable that it is 100:0.1-15, and it is more preferable that it is 100:0.2-10. When the blending amount of the heat-sensitive gelling agent (F) is less than the above lower limit, the effect of suppressing migration in the drying step is lowered, and the effect of providing a soft texture by the obtained leather material tends to be lowered, on the other hand, the upper limit. In the case of exceeding, in a relatively high temperature atmosphere such as in summer, the mixed liquid gels, or the mixed liquid tends to easily cause dispersion defects. Moreover, even if it mix|blends a (F) heat-sensitive gel agent exceeding the said upper limit, it will become unfavorable economically since performance will not improve further.

Moreover, when the mixture liquid which concerns on this invention contains the said (F) heat-sensitive gelling agent further, as content, it is said (A) from the viewpoint of being able to more fully maintain the thickness after drying of a foam, and the stability of the mixture liquid. ) It is preferable that it is 0.01-10 mass parts with respect to 100 mass parts of blending amounts of aqueous polyurethane resin, and it is also preferable that it is 0.05-5 mass parts.

As a thermosetting solidification temperature of the mixed liquid which concerns on this invention, it is preferable that it is 30-80 degreeC, and it is more preferable that it is 40-70 degreeC. In the present invention, the thermal coagulation temperature is when 5 to 10 g of the mixed solution is taken in a 20 mL glass test tube, the test tube is left in a water bath, and when the water bath is heated to 1°C/min, the contents lose fluidity and solidify. Is the temperature. When the thermosetting solidification temperature is less than the lower limit, the mixture tends to gel under a relatively high temperature atmosphere such as in summer, whereas when the thermosetting solidification is exceeded, the thermal solidification does not develop sharply, so that solidification In the process, coagulation tends to be weak, and migration inhibition tends to decrease, and the tendency becomes remarkable when it is dried (coagulated) at a relatively low temperature of about 85 to 120°C.

The viscosity of the mixed liquid according to the present invention is preferably 10 to 2,000 mPa·s, and 10 to 1,000 mPa, at a viscosity at 25° C. from the viewpoint that the flexible texture of the obtained leather material tends to be more improved. It is more preferable that it is s.

The method for producing the mixed liquid according to the present invention is not particularly limited, and can be produced by mixing the above-described components by appropriately known methods.

<Textile base>

In the method for producing a leather material of the present invention, the mixed solution is impregnated with a fiber base material, followed by drying by heating to obtain a leather material.

The fiber substrate according to the present invention is not particularly limited, and fabrics, knitted fabrics, or nonwoven fabrics can be suitably used. Moreover, although it does not specifically limit as a raw material of such a fiber base material, Polyamide fiber and polyester fiber are preferable from a viewpoint that the thickness is fully maintained and tends to obtain a close texture and dignity by natural leather.

When a nonwoven fabric is used as the fiber substrate, the thickness of the yarn is preferably 2.0 dtex or less from the viewpoint of improving the texture and quality of the resulting leather material. When the thickness of the thread of the nonwoven fabric exceeds the above upper limit, the texture of the resulting leather material tends to be rough and hard, and the quality tends to be impaired. Moreover, as a density of such a nonwoven fabric, it is preferable that it is 0.1-0.8 g/cm<3>, and it is more preferable that it is 0.30-0.55 g/cm<3>. When the density of the nonwoven fabric is less than the above lower limit, the abrasion resistance of the obtained leather material tends to decrease, and when a large amount of polyurethane resin is fixed to supplement it, the texture of the obtained leather material becomes rough and hard, and the quality tends to be damaged. There is this. On the other hand, when the density of the nonwoven fabric exceeds the above upper limit, the texture of the obtained leather material tends to be rough and hard, and the quality tends to be impaired. Moreover, although it does not specifically limit as thickness of the said fiber base material, It is preferable that it is 0.1-1 cm, and it is more preferable that it is 0.1-0.5 cm.

In the present invention, an additive may be further added to the above-mentioned mixed solution for the purpose of imparting processing suitability to the resulting leather material in a range not impairing the effects of the present invention. Examples of such additives include various kinds of lower alcohols, glycol-based solvents, alcohol-based nonionic surfactants, acetylene glycol-based special surfactants, silicone-based surfactants, fluorine-based surfactants, anionic surfactants, and cationic surfactants. Penetrant; Various stabilizers such as antioxidants, light stabilizers, and ultraviolet inhibitors; Various antifoaming agents such as mineral oil-based and silicone-based; Urethanization catalysts; Plasticizers; Coloring agents such as pigments; Pot life extension; And fillers such as acrylic resin beads and urethane resin beads. These additives may be used alone or in combination of two or more. When these additives were added to the mixed solution according to the present invention, the total added amount of the (A) water-based polyurethane resin, (B) blowing agent, and (C) formic acid ester compound blended in the mixed solution was 100 parts by mass. It is preferable that the amount is 50 parts by mass or less. In addition, when these compounds are used in the state of an oil-in-water dispersion in which the compounds are emulsified and dispersed in water, the mass means the remainder (solid content, non-volatile content) when the water-in-water dispersion is heated at a temperature of 105°C for 3 hours.

In addition, in the present invention, when the polyurethane resin having the carboxyl group and/or carboxylate group is used as the aqueous polyurethane resin (A), it is processed into the obtained leather material in a range not impairing the effects of the present invention. For the purpose of imparting aptitude, a crosslinking agent that reacts with the carboxyl group can be further added to the mixed solution. Examples of such a crosslinking agent include an oxazoline crosslinking agent, an epoxy crosslinking agent, an isocyanate crosslinking agent, a carbodiimide crosslinking agent, an aziridine crosslinking agent, a block isocyanate crosslinking agent, a water-dispersing isocyanate crosslinking agent, a melamine crosslinking agent, and the like. As said crosslinking agent, 1 type may be used individually or may be used in combination of 2 or more type. Among these crosslinking agents, a carbodiimide-based crosslinking agent is preferable from the viewpoint that light resistance, heat resistance, and water resistance of the resulting leather solvent tend to be further improved, and the amount of the (A) water-based polyurethane resin is 100 parts by mass. It is preferable that the amount is 0.5 to 10 parts by mass.

In the present invention, as a method of impregnating the fiber substrate with the mixed solution, the method is not particularly limited, and a well-known method can be used. As the impregnation method, for example, a conventionally known method such as impregnation processing including a dip-nip method, spray treatment, and a method of impregnating while coating with a coater can be preferably employed, and the concentration and treatment of the mixed solution. Conditions and the like can also be appropriately selected depending on the method employed. In addition, before impregnating the mixed liquid with the fiber substrate, the fiber substrate can be pretreated. In order to adjust the adhesive force between the fiber substrate and the polyurethane resin component, the pretreatment process uses a polymer aqueous solution containing polyvinyl alcohol, carboxymethyl cellulose, etc., a silicone water repellent, a fluorine water repellent, and the like to process the fiber substrate. It is preferred.

As the impregnation amount of the mixed liquid to the fiber substrate, the (A) water-based property in the obtained leather material from the viewpoint that the thickness retention rate of the fiber substrate is further improved, and the physical properties such as texture and friction fastness of the obtained leather material are further improved. It is preferable to impregnate so that the component derived from the polyurethane resin becomes 5 to 75% by mass.

In addition, as the impregnation according to the present invention, it is preferable to impregnate the inside of the obtained leather material so that the component derived from the above-mentioned (A) water-based polyurethane resin is fixed. According to the manufacturing method of the present invention, since migration is suppressed, it is possible to sufficiently fix the component derived from the above-mentioned (A) water-based polyurethane resin, the thickness of the fiber base material is maintained, and excellent friction fastness is achieved. When the cross-section of the leather material obtained using a scanning electron microscope is observed at a magnification of 150 times as a fixation state of the component derived from the aqueous polyurethane resin (A), not only the surface of the leather material, but also the leather material It is preferable that the adhesion of the component derived from the water-based polyurethane resin is confirmed in the 10% portion of the central portion occupied by the thickness of the (A), and no difference in the amount of resin adhesion is observed in the central portion and the surface portion of the leather material. It is more preferable not to.

In the present invention, the mixture is impregnated with the fiber substrate, followed by drying by heating, thereby generating carbon dioxide from the foaming agent (B) to solidify with foaming of the mixture. In the present invention, the heat drying method is not particularly limited, for example, dry heat drying using hot air; Wet drying with high temper steamer (H.T.S.), high pressure steamer (H.P.S.); Microwave irradiation drying or the like can be used, and among them, moist heat coagulation is preferably performed by wet drying using humidity (steam) from the viewpoint of resin coagulation and shortening of coagulation time. These drying methods may be used alone or in combination of two or more. Moreover, it is preferable that it is 1 to 30 minutes at the temperature of 80-180 degreeC as heat-drying condition (solidification condition), and it is more than 2 to 10 minutes at the temperature of 80-130 degreeC (more preferably 85-120 degreeC). desirable. By drying and solidifying the mixed solution impregnated in the fiber substrate in this way, the polyurethane resin can be fixed inside the fiber substrate. In the present invention, after the solidification of the mixed solution, dry heat drying for drying 1 to 60 minutes (preferably 2 to 30 minutes) moisture at 100 to 200°C (preferably 120 to 180°C) is performed. It is preferred.

By heating and drying the mixed solution impregnated in the fiber substrate as described above and foaming (generating carbon dioxide gas) and coagulating, the polyurethane resin having a uniform foam structure is fixed inside the fiber substrate, thereby providing the leather material of the present invention. Can be obtained.

The leather flux of the present invention thus obtained can be dyed. The leather solvent of the present invention can sufficiently retain its flexible texture even when dyed. The dyeing method is not particularly limited, and may be a pre-impregnation post-staining method of dyeing after fixing the polyurethane resin to the fiber substrate, or a post-impregnation pre-staining method of fixing the polyurethane resin after dyeing the fiber substrate. .

In addition, the leather flux of the present invention can also be formed into a leather flux coated with a silver surface by forming a skin layer. As a method for forming such an epidermal layer, any method known in the art may be used, and is not particularly limited. For example, an epidermal layer is formed by applying a material for the epidermal layer to release paper and evaporating the moisture of the epidermal material, followed by forming the epidermal layer. A method of applying an adhesive to the surface and bonding with the leather material of the present invention, and evaporating the moisture of the adhesive, or a method of bonding both after evaporating the moisture to form an adhesive layer (release paper transfer method). In addition, after forming the skin layer on the release paper, the heat transfer method of bonding the skin layer of the present invention to the skin layer by heat; A spraying method of spraying the material for the skin layer directly on the leather material of the present invention; The direct coat method etc. which apply|coat the material for skin layers on the leather material of this invention with a gravure coater, a knife coater, a comma coater, an air knife coater, etc. are mentioned. Among these methods for forming the skin layer, a release paper transfer method is preferable from the viewpoint of further improving physical properties such as friction fastness of the skin layer obtained. The material and adhesive for the skin layer used in the release paper transfer method are not particularly limited as long as they can be bonded to the leather material of the present invention, but can further maintain the thickness of the fiber base material, and have better properties such as texture and friction fastness. From the viewpoint of obtaining this, a polyurethane resin is preferable, and from the viewpoint of reducing VOC-free and environmental load, an aqueous or solvent-free system is preferred.

The leather material of the present invention can be used in fields such as vehicles, furniture, medical care, shoes, bags, pockets, sandals, sundries and polishing.

Example

Hereinafter, the present invention will be described in more detail based on Examples and Comparative Examples, but the present invention is not limited to the following Examples. In addition, each measurement and evaluation in each synthesis example, an Example, and a comparative example were performed by the following method, respectively.

(1) Measurement of thermal solidification temperature

5.0 g of a water-based dispersion of the aqueous polyurethane resin obtained in each polyurethane resin synthesis example and the mixed solution obtained in each of the examples and comparative examples were taken in a 20 mL glass test tube, and each test tube was left in a water bath, and the water bath was 1°C/ The temperature was increased in minutes to measure the temperature at which the contents lost solidity and solidified, and was set as a thermal solidification temperature.

(2) 100% modulus value measurement

Using a water-based dispersion of the aqueous polyurethane resin obtained in each synthetic example of the polyurethane resin, a dumbbell-shaped test piece 3 was prepared in the same manner as in JIS K 6250 (2006) 8. In the same manner as in K 6251 (2010), the value of a predetermined elongation tensile stress (㎫) in the case where the distance between the marked lines was 100% elongated (when doubled) was measured, and it was set as a value of 100% modulus.

(3) Viscosity measurement

The viscosity [mPa·s] at 25° C. of the mixed liquid obtained in each of the Examples and Comparative Examples was measured by a method according to JIS K7117-1 (1999) using a single cylindrical rotational viscometer (Type B viscometer).

(4) Softness measurement

For the leather material after the dyeing processing obtained by each example and each comparative example, according to ISO 17235:2015 (IULTCS/IUP 36), a softness tester (leather softness measuring device ST300: UK, manufactured by MSA Engineering Systems) Using, the softness (softness) [mm] was measured. In addition, the numerical value of the stiffness indicates the penetration depth, and the larger the numerical value, the more flexible it is.

(5) Evaluation of texture

For the leather material after the dyeing processing obtained by each example and each comparative example, by touch, the following criteria:

Level 5: Flexible and highly resilient texture

Level 4: Flexible and resilient texture

Level 3: Soft yet slightly resilient texture

Level 2: Slightly rough, hard and paper-like (paper-like) texture

Level 1: Rough, hard and paper-like (paper-like) texture

According to the evaluation.

(Synthesis example 1 of aqueous polyurethane resin)

In a four-necked flask equipped with a stirrer, reflux cooling tube, thermometer, and nitrogen introduction tube, 167.9 g of polytetramethylene glycol (weight average molecular weight 1,000), randomly studied polymer of ethylene oxide and propylene oxide (weight average molecular weight 1,000, oxyethylene Group content 70 mass%) 36.9 g, 1,4-butanediol 3.2 g, trimethylolpropane 4.0 g, dibutyl tin dilaurate 0.002 g and methyl ethyl ketone 128.6 g were added and mixed uniformly, followed by dicyclohexyl 88.0 g of methane diisocyanate was added and reacted at 80° C. for 300 minutes to obtain a methyl ethyl ketone solution of an isocyanate group terminated prepolymer having a free isocyanate group content of 1.0 mass%.

After cooling the obtained methyl ethyl ketone solution of the isocyanate group terminal prepolymer to 30° C. or less, 0.5 g of decyl phosphate ester and 12.0 g of 20 mol of ethylene oxide adduct of tristyrylphenol are added, mixed uniformly, and then 435.0 g of water was slowly added using a fur blade to emulsify and disperse the whole phase to obtain an emulsion dispersion. Then, an aqueous polyamine solution in which 3.9 g of piperazine hexahydrate and 2.1 g of diethylenetriamine was dissolved in 23.9 g of water was added to the emulsion dispersion, followed by a chain extension reaction for 90 minutes, and then desolvated at 35° C. under reduced pressure. A water-based dispersion of a stable aqueous polyurethane resin having a non-volatile content of 40.0% by mass, a viscosity of 250.0 mPa·s (BM viscometer, No. 2 rotor, 60 rpm) and an average particle diameter of 550 nm was obtained.

The content of the carboxyl group, carboxylate group, sulfo group and sulfonate group in the aqueous polyurethane resin was all 0.0% by mass, and the value of 100% modulus was 2 MPa. In addition, the water-based dispersion of the water-based polyurethane resin gelated at 65°C and had thermosetting properties.

(Synthesis example 2 of aqueous polyurethane resin)

In a four-necked flask equipped with a stirrer, reflux cooling tube, thermometer and nitrogen introduction tube, 157.0 g of 1,6-hexanediol polycarbonate polyol (average molecular weight 2,000), 7.5 g of neopentyl glycol, 1.3 g of trimethylolpropane, 9.5 g of 2,2-dimethylolpropionic acid, 0.001 g of dibutyltin dilaurate and 105 g of methyl ethyl ketone were added and mixed uniformly, and then 69.7 g of isophorone diisocyanate was added and reacted at 80°C for 300 minutes. , A methyl ethyl ketone solution of an isocyanate group terminal prepolymer having a carboxyl group having a free isocyanate group content of 1.9 mass% with respect to nonvolatile matter was obtained.

After cooling the obtained methyl ethyl ketone solution of the isocyanate group terminal prepolymer to 50° C. or less, 6.8 g of triethylamine was added to perform a neutralization reaction at 40° C. for 30 minutes. Subsequently, the neutralized solution was cooled to 30° C. or lower, and 421.9 g of water was gradually added using a disper blade to emulsify and disperse the neutralized product of the isocyanate group-terminal prepolymer having a carboxy group, thereby obtaining a dispersion. Then, an aqueous polyamine solution in which 60 g by mass of 5.2 g of hydrazine and 1.1 g of diethylenetriamine were dissolved in 20 g of water was added to the dispersion, followed by a chain elongation reaction at 35° C. for 60 minutes, and then under reduced pressure at 35° C. To obtain a water dispersion of an aqueous polyurethane resin having a nonvolatile content of 35.0 mass%, a viscosity of 120 mPa·s (BM viscometer, No. 2 rotor, 60 rpm), a pH value of 7.8, a stable carboxy group having an average particle diameter of 90 nm, and a carboxylate group. .

The sum of the carboxyl group content and the carboxylate group content in this aqueous polyurethane resin was 1.3% by mass, and the value of 100% modulus was 2 Pa. In addition, the oil-in-water dispersion of the polyurethane resin having this carboxyl group and carboxylate group was not gelled even when heated at 90°C, and had no thermal coagulation property.

(Example 1)

(A) 65 parts by weight of water-based dispersion of aqueous polyurethane resin obtained in Synthesis Example 1 of aqueous polyurethane resin (26 parts by weight of solids), (B) 16 parts by weight of aqueous 8% aqueous solution (1.3 parts by weight of solids (medium weight)) ), (C) 1 part by mass of ethylene glycol formate, and (D) 18 parts by mass of water were uniformly mixed to prepare a mixed solution having an aqueous polyurethane resin concentration of 26% by mass. The heat-setting solidification temperature of the obtained mixed solution was 60°C, and the viscosity at 25°C was 40 mPa·s.

This mixed solution was impregnated with a raw fabric (nonwoven fabric containing polyester fiber, 0.5 dtex, density 0.3 g/cm 3) using a slit mangle so that the pickup was 100% by mass, followed by wet drying (wet heat solidification). Relative humidity 60%, temperature 100° C. for 5 minutes, followed by dry heat drying at 130° C. for 5 minutes to obtain artificial leather (leather material). Further, the obtained artificial leather was dyed and RC soaped under the following conditions to obtain an artificial leather dyed fabric (leather material after dyeing).

<dyeing condition>

Dyeing machine: Mini color dyeing machine (Techsam Kiken)

Dye: Kayalon Microester Blue DX-LS conc (manufactured by Nippon Kayaku Co., Ltd.) 0.10% o.w.f.

Kayalon Maicroester Yellow DX-LS (manufactured by Nippon Kayaku Co., Ltd.)2.00% o.w.f.

Kayalon Maicroester Red DX-LS (manufactured by Nippon Kayaku Co., Ltd.) 0.80% o.w.f.

Dyeing aid: Nikka Sun Salt RM-3406 (manufactured by Nikka Chemical Co., Ltd.) 0.5 g/L

pH adjuster: 90% mass acetic acid 0.3cc/L

Yogbi: (1:20)

Dyeing conditions: 130° C.×60 minutes (heating rate 2° C./min).

<RC conditions>

RC bath: sodium hydroxide 2g/L

Hydrosulfite 2g/L

Yogbi: (1:20)

RC conditions: 80°C×20 minutes (heating rate 2°C/min).

The result of performing softness measurement and texture evaluation on the obtained artificial leather dyed fabric (dyeing material after dyeing processing) is shown in Table 1 below as well as the composition and viscosity of the mixed solution.

(Examples 2 to 6)

In the same manner as in Example 1, except that the composition of the mixture was set to the composition shown in Table 1 below, artificial leather (leather material) and artificial leather dyed fabric (dye material after dyeing) were obtained. The result of performing softness measurement and texture evaluation on the obtained artificial leather dyed fabric (dyeing material after dyeing processing) is shown in Table 1 below together with the composition and viscosity of the mixed solution. In addition, the mass part described in the column of water in the table shows the amount of water added in addition to the water mixed as each dispersion or aqueous solution (hereinafter the same).

(Examples 7 to 13)

In the same manner as in Example 1, except that the composition of the mixed solution was set to the composition shown in Table 2 below, artificial leather (leather material) and artificial leather dyed cloth (dye material after dyeing) were obtained, respectively. The result of performing softness measurement and texture evaluation on the obtained artificial leather dyed fabric (dyeing material after dyeing processing) is shown in Table 2 below together with the composition and viscosity of the mixed solution.

(Comparative Examples 1 to 5)

An artificial leather (leather material) and an artificial leather dyeing fabric (dyeing material after dyeing processing) were obtained in the same manner as in Example 1, except that the composition of the mixture was set to the composition shown in Table 3 below. The result of performing softness measurement and texture evaluation on the obtained artificial leather dyeing fabric (dyeing material after dyeing processing) is shown in Table 3 below together with the composition and viscosity of the mixed solution. In addition, in Comparative Example 4, foaming occurred at the time when the mixed solution was prepared, and treatment with the fiber substrate was not possible.

As apparent from the results shown in Tables 1 to 3, in the leather materials obtained in Examples 1 to 13, it was confirmed that the flexible texture was excellent, and the leather materials excellent in the flexible texture were confirmed by the method for producing the leather materials of the present invention. It was confirmed that it was easily and efficiently obtained. In addition, when a mixed solution further containing (E) a thickener and/or (F) a heat-sensitive gelling agent is used (for example, Examples 3 to 6, 8 to 13), it is obtained that a leather material having a more flexible texture is obtained. Was confirmed.

On the other hand, in the case where a mixed solution containing neither of the (B) foaming agent and (C) formic acid ester compound was used (for example, Comparative Examples 1 and 2), it was confirmed that the soft texture was poor in the obtained leather material. In addition, in the case of using a mixed solution containing ammonium sulfate, which is a substance that generates an acid by heating, instead of the (C) formic acid ester compound according to the present invention (for example, Comparative Examples 3 and 5), Therefore, it was confirmed that the soft texture was inferior, and when a mixed liquid containing citric acid was used (for example, Comparative Example 4), foaming occurred at the time of preparing the mixed liquid, and the fiber substrate could not be treated. .

As described above, according to the present invention, it becomes possible to provide a method for producing a leather material that can easily and efficiently obtain a leather material having excellent flexible texture.

Further, according to the present invention, since the porous resin layer can be efficiently and easily formed in a fiber base material such as a non-woven fabric, it is possible to focus and fix the fiber, thereby suppressing damage to the texture, and in the fiber base material. Since the voids can be filled with a resin layer, improvement in repellency and improvement in the physical strength (tensile strength, tear strength, flex resistance) of artificial leather can also be expected. Therefore, the manufacturing method of the leather material of the present invention is particularly useful as an industrial manufacturing method of the leather material, and the leather material obtained by the manufacturing method of the present invention is a vehicle, furniture, medical care, bag, shoe, pouch, sundries. , It can be suitably used in industrial fields such as polishing, and furthermore, it can be suitably used as a stable and high-quality leather material by providing a skin layer.

Claims (8)

(A) A water-based polyurethane resin, (B) a foaming agent that generates carbon dioxide gas by heating and/or acid, (C) a formic acid ester compound, and (D) a mixture solution containing water is heated after impregnation with the fiber substrate A method for producing a leather material by drying to obtain a leather material. The method for producing a leather material according to claim 1, wherein the blowing agent (B) is a carbonate. The mixing amount ratio (A:B:C) of the (A) water-based polyurethane resin, the (B) blowing agent and the (C) formic acid ester compound in the mixed solution according to claim 1 or 2, is a mass ratio. 100:1 to 50:1 to 75, a method for producing a leather material. The method for producing a leather material according to claim 1 or 2, wherein the mixed solution further contains a thickener (E). The method for producing a leather material according to claim 1 or 2, wherein the mixed solution further contains (F) a heat sensitive gelling agent. The aqueous polyurethane resin according to claim 1 or 2, wherein the aqueous polyurethane resin is a polyurethane resin having at least one anionic group selected from the group consisting of carboxyl groups, carboxylate groups, sulfo groups and sulfonate groups, Method for producing leather material. The method for producing a leather material according to claim 1 or 2, wherein the mixture has a thermal solidification temperature of 30 to 80°C. The leather material according to claim 1 or 2, wherein the mixture is impregnated with the fiber substrate so that the component derived from the aqueous polyurethane resin (A) adheres to 10% of the central portion occupying the thickness of the leather material. Method of manufacture.