JP2000303371A - Method for producing leather-like sheet material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for producing a leather-like sheet having excellent softness and fullness, good feeling, touch, and physical properties similar to natural leather using a resin emulsion and the like. To provide a natural leather-like sheet. SOLUTION: The following conditions (i) to (ii) are applied to a fibrous base material.
(i) the composite resin emulsion is thermosensitive gelling; (ii) the elasticity at 90 ° C. of a 100 μm thick film obtained by drying the composite resin emulsion at 50 ° C. And (iii) the composite resin emulsion is prepared by mixing the ethylenically unsaturated monomer (B) in the presence of the polyurethane-based emulsion (A) with a ratio of 1.0 × 10 ^{7 to} 5.0 × 10 ⁸ dyn / cm ^2. Is an emulsion obtained by emulsion polymerization of the polyurethane-based emulsion (A) in a ratio of 90/10 to 10/90 by weight of the polyurethane / weight of the ethylenically unsaturated monomer (B). The above object is achieved by a method for producing a coagulated leather-like sheet and a leather-like sheet obtained thereby.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for producing a leather-like sheet and a leather-like sheet obtained thereby. More specifically, the present invention relates to a method for producing a leather-like sheet by impregnating a fibrous base material with a specific composite resin emulsion and coagulating the same, and a leather-like sheet obtained by the method. The leather-like sheet obtained by the present invention has a feeling close to that of natural leather, flexibility and flexibility, as compared with a conventional leather-like sheet obtained by impregnating a fibrous base material with an emulsion resin. Excellent feeling of fulfillment, touch and durability.

[0002]

2. Description of the Related Art As a substitute for natural leather (artificial leather),
2. Description of the Related Art Sheet materials in which a resin component such as polyurethane is impregnated into a fibrous base material as a binding agent have been conventionally produced. Typical production methods include a wet method in which a resin component dissolved in an organic solvent such as dimethylformamide is impregnated into a fibrous base material and then solidified in a non-solvent such as water, and the resin component is dissolved in an organic solvent. Dry method in which a fibrous base material is impregnated with a solution dissolved in water or an emulsion dispersed in water and then dried.

[0003] In the case of the wet method, it is possible to obtain a sheet-like material having a feeling closer to natural leather than in the case of the dry method, but the productivity is inferior and the use of an organic solvent such as dimethylformamide is indispensable. There is a disadvantage that it is.
On the other hand, in the case of using a resin emulsion in the dry method, it is possible to obtain a sheet-like material without using an organic solvent, but the texture is remarkably compared to a sheet-like material obtained by a wet method. Inferior. The reason is that, in the sheet-like material obtained by the dry method, the resin moves locally in the fibrous base material during the drying process, and forms a structure in which the fiber is strongly restrained at that portion, thereby forming a sheet-like material. This is because the material loses its flexibility and becomes hard. If the amount of the adhered resin is reduced so as not to impair the flexibility, the texture of the fibrous base material such as a nonwoven fabric appears as it is, and a leather-like texture cannot be obtained. If an attempt is made to obtain a feeling of fulfillment or a leather-like feeling by increasing the hardness, the flexibility decreases and the skin becomes hard, and in any case, a high-grade feeling similar to that of natural leather cannot be obtained.

In a dry method using an emulsion resin, it is conceivable that a softener is applied after the resin is applied to develop flexibility. However, it is necessary to add a step of applying the softener, and the productivity is reduced. Even if a softening agent is applied, it is difficult to give a high-grade feel similar to that of natural leather. As a dry method using an emulsion resin, a method of producing a base fabric for synthetic leather by impregnating a cloth with a mixed resin emulsion of a polyurethane emulsion and a polyacrylate emulsion and treating with hot water (Japanese Patent Laid-Open No. 55-55)
No. 128078) and a non-woven sheet comprising a fiber layer mainly composed of ultrafine fibers having a single fiber fineness of 0.5 denier or less, a water-based polyurethane emulsion having an average particle size of 0.1 to 2.0 μm, and inorganic salts. A method of producing an artificial leather by applying an emulsion liquid obtained by dissolving and mixing the same and heating and drying the same (JP-A-6-316877) has been proposed.
However, it is hard to say that the artificial leather obtained by these methods is sufficiently improved in terms of flexibility, feeling, and the like. Therefore, in the production of artificial leather, a high-quality artificial leather can be obtained, but at present, the wet method, which has low productivity and requires the use of an organic solvent, is industrially exclusively used. However, the method for producing a leather-like sheet material represented by the above-mentioned dry method of impregnating a fibrous base material with an aqueous resin emulsion and heating and coagulating the fibrous base material is performed when the fibrous base material is impregnated with the resin or impregnated with the resin. Since there is no need to use an organic solvent when coagulating the resin, it is extremely effective in terms of environmental compatibility, work environment safety, and simplification of the process. In this regard, flexibility is achieved using an aqueous resin emulsion. Also, there is a strong demand for the development of a technology capable of producing a high-quality leather-like sheet having excellent fulfillment.

[0005]

SUMMARY OF THE INVENTION An object of the present invention is to solve the problems in the conventional art for producing artificial leather using a resin emulsion, that is, problems such as lack of flexibility and lack of fulfillment in the obtained sheet-like material. Using a resin emulsion, a method for producing a leather-like sheet having excellent softness and fullness, and a good feeling, touch, and physical properties similar to natural leather, and such a leather-like sheet It is to provide things.

[0006]

Means for Solving the Problems As a result of repeated studies by the present inventors to achieve the above object, when a specific composite resin emulsion having heat-sensitive gelling property is used as a resin emulsion, the emulsion is converted into a fibrous material. When the base material is impregnated and gelled, the composite resin solidifies without constraining the fibers and fills the fiber space, thereby providing flexibility and a sense of fulfillment, similar to natural leather. The inventors have found that a high-quality leather-like sheet having extremely good feeling, touch and physical properties can be obtained, thereby completing the present invention.

That is, the present invention provides a method for producing a leather-like sheet, wherein a fibrous base material is impregnated with a composite resin emulsion satisfying the following conditions (i) to (iii) and solidified. (I) the composite resin emulsion is thermosensitive gelling; (ii) a 100 μm thick film obtained by drying the composite resin emulsion at 50 ° C. has an elastic modulus at 90 ° C. of 1.0 × is ^{10 7 ~5.0 × 10 8 dyn /} cm 2; and (iii) the composite resin emulsion, an ethylenically unsaturated monomer (B) in the presence of a polyurethane-based emulsion (a), a polyurethane-based emulsion ( It is an emulsion obtained by emulsion polymerization in which the weight of the polyurethane in A) / the weight of the ethylenically unsaturated monomer (B) is 90/10 to 10/90.

[0008] The present invention also relates to a leather-like sheet obtained by the above production method.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail. First, the fibrous base material will be described. The fibrous base material used in the present invention only needs to have an appropriate thickness and a sense of fulfillment and have a soft feeling, and a leather-like sheet material has been conventionally used. Various fibrous base materials such as a nonwoven fabric and a knitted woven fabric used in the production of woven fabrics can be used. Among them, in the present invention, as the fibrous base material, a fibrous base material composed of only a nonwoven fabric or a laminate of a nonwoven fabric having at least one nonwoven fabric layer and a woven and / or knitted fabric (for example, a nonwoven fabric layer) And a two-layer structure composed of a knitted and woven fabric layer, a three-layer structure composed of a nonwoven layer on the front and back sides and a knitted woven fabric layer at the center, and the like, and a fibrous substrate composed of only a nonwoven fabric is more preferably used. Examples of the nonwoven fabric preferably used as the fibrous substrate include an entangled nonwoven fabric and a wrap-type nonwoven fabric. Among them, an entangled nonwoven fabric is preferably used.

The fibers constituting the fibrous base material include polyester fibers, polyamide fibers, acrylic fibers, polyolefin fibers, polyvinyl chloride fibers, polyvinylidene chloride fibers and polyvinyl alcohol fibers. Synthetic fiber; natural fibers such as cotton, wool, hemp and the like. Among them, the fibrous base material is preferably mainly composed of synthetic fibers such as polyester fibers, polyamide fibers, and acrylic fibers. Further, the above-mentioned fibers constituting the fibrous base material are:
Normal fibers that do not shrink or elongate, shrinkable fibers, latent spontaneously extensible fibers, various composite fibers and mixed spun fibers (for example, multilayer laminated latent splittable composite fibers and mixed spun fibers),
Any of ultrafine fibers, bundled fibers thereof, and special porous fibers may be used.

[0011] The thickness of the fibers constituting the fibrous base material is not particularly limited and can be selected according to the intended use of the obtained leather-like sheet material.
It is preferably from 01 to 10 denier, and from 0.02 to 8
More preferably, it is denier.

The thickness of the fibrous base material can be arbitrarily selected depending on the intended use of the obtained leather-like sheet material, but is preferably from 0.3 to 3.0 mm from the viewpoint of hand. 0.
More preferably, it is 8 to 2.5 mm.

The apparent density of the fibrous base material is soft,
From the viewpoint of leather-like sheet having an appropriate elasticity feeling and resilience is obtained is preferably from 0.1 to 0.5 g / cm ^3, and even a 0.15~0.45g / cm ³ More preferred. If the apparent density of the fibrous base material is less than 0.1 g / cm ³ , the resulting leather-like sheet will have poor resilience and a feeling of stiffness, and tend to impair the feeling of natural leather. There is. On the other hand, if the apparent density of the fibrous base material is larger than 0.5 g / cm ³ , the resulting leather-like sheet-like material tends to have no feeling of stiffness or have a poor rubber-like feeling.

Among them, according to the present invention, as the fibrous base material, the apparent density formed using at least a part of the shrinkable polyethylene terephthalate fiber is 0.25.
It is preferable to use a nonwoven fabric having a thickness of up to 0.50 g / cm ^{3. When} such a fibrous base material is used, a leather-like sheet having extremely excellent flexibility and stiffness can be obtained. In this case, as the shrinkable polyethylene terephthalate fiber constituting the fibrous base material, one having a shrinkage of 10 to 60% in hot water at 70 ° C. is preferably used. The nonwoven fabric described above is, for example, a nonwoven fabric obtained by using ordinary polyester fibers and latent spontaneous extensible fibers described in JP-A-56-37353 and JP-A-53-53388 in an appropriate ratio. Can be obtained by shrinking in warm water, followed by dry heat treatment and spontaneous elongation.

In the present invention, it is preferable that a fiber treating agent having an action of preventing adhesion between the fiber and the composite resin is previously applied to the fibrous base material. By using a fibrous base material to which the fiber treatment agent has been applied in advance, and impregnating and coagulating the specific composite resin emulsion used in the present invention,
The constraint of the fiber by the composite resin is weakened, and it becomes easy to obtain a leather-like sheet-like material similar to natural leather, which is excellent in flexibility and fullness. As a fiber treatment agent having an action of preventing adhesion between the fiber and the composite resin, a silicone-based soft water repellent is preferably used. Specific examples of silicone-based soft water repellents include dimethyl silicone oil (oily dimethylpolysiloxane), methylphenyl silicone oil (oily methylphenylpolysiloxane), and methyl hydrogen silicone oil (oily methyl hydrogen polysiloxane). Polysiloxane having oily methylhydrogensiloxy units and dimethylsiloxy units, or a mixture thereof), diorganopolysiloxanediol, fluorosilicone oil, silicone polyether copolymer, alkyl-modified silicone oil, higher fatty acid-modified silicone oil And amino-modified silicone oils and epoxy-modified silicone oils, and one or more of these can be used.

Among the above silicone-based soft water repellents, dimethyl silicone oil (oily dimethylpolysiloxane) and methyl hydrogen silicone oil (oily methyl hydrogen polysiloxane, oily methyl hydrogen siloxy unit) Polysiloxanes having dimethylsiloxy units or mixtures thereof)
Is preferably used because it has an excellent effect of preventing the adhesion between the fiber and the composite resin and is easily available.
In the above-described silicone oil, as the number of Si—H bonds increases, the water repellency improves, and the baking temperature can be lowered. Therefore, when the methyl hydrogen silicone oil used in combination with the dimethyl silicone oil is a polysiloxane having a methyl hydrogen siloxy unit and a dimethyl siloxy unit, use one having a methyl hydrogen siloxy unit ratio of 60 mol% or more. Is preferred. The weight ratio of dimethyl silicone oil: methyl hydrogen silicone oil in the soft water repellent is preferably 1: 9 to 9: 1. If the proportion of dimethyl silicone oil (dimethylpolysiloxane) is less than 10% by weight of the whole,
The texture of the obtained leather-like sheet tends to be hard, while if the proportion of methyl hydrogen silicone oil is less than 10% by weight, the water-repellency of the obtained leather-like sheet becomes insufficient. Tend to be.

The silicone type soft water repellent includes an oil type, an emulsion type, a solution type and the like, and any of them can be used in the present invention. Emulsion type is preferably used. Further, the silicone-based soft water repellent can contain a metal salt with an organic acid such as tin, titanium, zirconium, or zinc as a catalyst in order to impart high water repellency to the fibrous base material at a low temperature. .

As a method for applying the above-mentioned fiber treating agent to the fibrous base material, any method may be employed as long as it can uniformly apply the fiber treating agent to the fibrous base material. Among them, for example, when the fiber treatment agent is a silicone-based soft water repellent, the soft water repellent is diluted with water to obtain an aqueous liquid having a concentration of 0.5 to 5% by weight, if necessary. A treatment liquid is prepared by adding a catalyst thereto, and the fibrous base material is immersed in the treatment liquid. Then, the fibrous base material is taken out of the treatment liquid and a diaphragm for adjusting the amount of the soft water repellent is attached. In this case, a method of heating and drying after pre-drying in some cases is preferably adopted. The heating and drying temperature at that time, in order to strongly adhere the silicone soft water repellent to the fibrous base material,
Generally, the temperature is preferably from 50 to 150 ° C.

The amount of the fiber treating agent deposited on the fibrous base material (the amount after heat drying) is preferably 0.05 to 5% by weight based on the weight of the fibrous base material. More preferably, it is from 3 to 3% by weight. If the amount of the fiber treating agent is less than 0.05% by weight, the obtained leather-like sheet tends to have insufficient flexibility and water repellency.
If the amount is more than 10% by weight, the fiber treatment agent bleeds out to the surface of the leather-like sheet material, which tends to deteriorate the tactile sensation of the surface, poor appearance, and adhesion of the soft water repellent to other objects.

Further, the fibrous base material is preliminarily treated with a urea resin, a melamine resin, an ethylene urea resin, a glyoxal resin or the like in order to improve the washing resistance of the leather-like sheet. You may leave.

In the present invention, a fibrous base material is impregnated with a thermosensitive gelling composite resin emulsion and solidified to produce a leather-like sheet (the above condition (i)).

Here, the thermogelling emulsion referred to in the present invention means an emulsion which loses fluidity when heated and becomes a gel. The thermogelling temperature at which the thermogelling composite resin emulsion loses fluidity by heating and gels is preferably 30 to 70 ° C, more preferably 40 to 70 ° C. If the composite resin emulsion is not thermosensitive gelling, when the fibrous base material is impregnated with the emulsion and dried and gelled with hot air, the migration of the emulsion particles in the fibrous base material occurs, and the composite resin becomes a fibrous base material. Dispersion cannot be uniformly imparted to the material, and the leather-like sheet-like material has poor physical properties such as high elongation and flexibility, and has a poor feel. When the emulsion is coagulated in warm water after impregnating the fibrous base material with the composite resin emulsion, the emulsion is caused to flow out into the warm water, and the composite resin can also be uniformly dispersed and provided in the fibrous base material. As described above, the strength and elongation of the leather-like sheet,
This results in deterioration of physical properties such as flexibility and deterioration of feeling.

As the thermogelling composite resin emulsion, an emulsion containing a thermosetting gelling resin itself or a thermosetting gelling resin obtained by adding a thermogelling agent to an emulsion is used. Any of the emulsions can be used. Examples of the thermosensitive gelling agent for obtaining a thermogelling composite resin emulsion include, for example,
Inorganic salts, polyethylene glycol-type nonionic surfactants, polyvinyl methyl ether, polypropylene glycol, silicone polyether copolymer, polysiloxane, and the like can be used, and one or more of these can be used.

Among them, a combination of an inorganic salt and a polyethylene glycol type nonionic surfactant is preferably used as the heat-sensitive gelling agent because it exhibits good heat-sensitive gelling properties. As the inorganic salt in that case, a monovalent or divalent metal salt capable of lowering the cloud point of the polyethylene glycol type nonionic surfactant is preferably used, and specific examples thereof include sodium carbonate, sodium sulfate, and chloride. Examples thereof include calcium, calcium sulfate, zinc oxide, zinc chloride, magnesium chloride, potassium chloride, potassium carbonate, sodium nitrate, and lead nitrate. One or more of these can be used. Specific examples of the polyethylene glycol type nonionic surfactant include ethylene oxide adducts of higher alcohols, ethylene oxide adducts of alkyl phenols, ethylene oxide adducts of fatty acids, and ethylene oxide adducts of fatty acid esters of polyhydric alcohols. Examples thereof include an ethylene oxide adduct of a higher alkylamine and an ethylene oxide adduct of polypropylene glycol, and one or more of these can be used.

When a heat-sensitive gelling emulsion containing a heat-sensitive gelling agent is used, the amount of the heat-sensitive gelling agent is 0.2 to 20 parts by weight based on 100 parts by weight of the resin in the emulsion. Is preferred.

The elastic modulus at 90 ° C. of a 100 μm thick film obtained by drying the composite resin emulsion used in the present invention at a temperature of 50 ° C. is 1.0 × 10 ^{7 to} 5.0 ×.
10 ⁸ dyn / cm ² [the above condition (ii)];
It is preferably 5 × 10 ^{7 to} 3.0 × 10 ⁸ dyn / cm ² . The elastic modulus at 90 ° C. is 1.0 × 10 ⁷ dyn
When a composite resin emulsion which gives the dry film of less than / cm ² is used, the fibers are strongly restrained by the composite resin when the fibrous base material is impregnated with the emulsion and solidified, and as a result, the obtained sheet It has a poor feeling of fibrous material that does not have a sense of fulfillment and does not approximate natural leather. On the other hand, the elastic modulus at 90 ° C. is 5.0 × 1
When a composite resin emulsion that gives the dry film exceeding 0 ⁸ dyn / cm ² is used, the resulting sheet-like material has a hard feeling with poor flexibility. The method for measuring the elastic modulus of the dried film in the present invention is as described in the following Examples.

The α-dispersion temperature (Tα) of a 100 μm thick film obtained by drying the composite resin emulsion used in the present invention at a temperature of 50 ° C. is preferably -10 ° C. or less, and -20 ° C. It is more preferable that:
When the dry film obtained from the composite resin emulsion has the above-mentioned α-dispersion temperature (Tα), the resulting leather-like sheet material has excellent physical properties such as cold resistance and bending resistance. The method for measuring the α-dispersion temperature (Tα) of the dried film in the present invention is as described in the following Examples.

The composite resin emulsion used in the present invention is
In the presence of the polyurethane-based emulsion (A), the ethylenically unsaturated monomer (B) was mixed with the polyurethane-based emulsion (A) at a ratio of 90/10 to 10 / (weight of polyurethane / weight of ethylenically unsaturated monomer (B)). It is an emulsion obtained by emulsion polymerization at a ratio of 90 [condition (iii) above].

The polyurethane contained in the polyurethane emulsion (A) is generally a polymer polyol,
It can be produced by appropriately combining and reacting an organic diisocyanate compound and a chain extender.

The above-mentioned high molecular polyol used in the production of polyurethane includes polyester polyol,
Polyether polyols, polycarbonate polyols, polyester polycarbonate polyols and the like can be mentioned, and polyurethane can be formed using one or more of these polymer polyols.

Polyester polyols that can be used in the production of polyurethane are prepared by directly esterifying a polyol component with a polycarboxylic acid component such as a polycarboxylic acid, an ester thereof, or an ester-forming derivative such as an anhydride, according to a conventional method. Alternatively, it can be produced by a transesterification reaction. Further, the polyester polyol can also be produced by ring-opening polymerization of lactone.

As a polycarboxylic acid component which is a raw material for producing a polyester polyol which can be used for producing a polyurethane, those generally used in producing a polyester can be used. For example, succinic acid, glutaric acid, adipine Acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, dodecanedioic acid, methyl succinic acid,
Aliphatic having 4 to 12 carbon atoms such as 2-methylglutaric acid, 3-methylglutaric acid, trimethyladipic acid, 2-methyloctanedioic acid, 3,8-dimethyldecandioic acid, and 3,7-dimethyldecandioic acid Dicarboxylic acids; alicyclic dicarboxylic acids such as cyclohexanedicarboxylic acid; aromatic dicarboxylic acids such as terephthalic acid, isophthalic acid, orthophthalic acid, and naphthalenedicarboxylic acid; tricarboxylic acids such as trimellitic acid and trimesic acid; And the like, and the polyester polyol can be formed using one or more of the above-mentioned polycarboxylic acid components. Among them, the polyester polyol is preferably produced using an aliphatic dicarboxylic acid or an ester-forming derivative thereof as a polycarboxylic acid component.

The polyol component which is a raw material for producing a polyester polyol which can be used for producing polyurethane includes, for example, ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol,
1,3-propanediol, 2-methyl-1,3-propanediol, 2,2-diethyl-1,3-propanediol, 1,3-butylene glycol, 1,4-butanediol, 3-methyl-1 , 5-pentanediol,
1,6-hexanediol, 1,8-octanediol, 2-methyl-1,8-octanediol, 2,7-
Aliphatic diols having 2 to 15 carbon atoms such as dimethyl-1,8-octanediol, 1,9-nonanediol, 2,8-dimethyl-1,9-nonanediol, and 1,10-decanediol; Alicyclic diols such as cyclohexanediol, cyclohexanedimethanol and dimethylcyclooctanedimethanol; 1,4-bis (β-
Aromatic diols such as hydroxyethoxy) benzene;
Polyalkylene glycols; polyols such as glycerin, trimethylolpropane, butanetriol, and pentaerythritol can be mentioned, and one or more of the above-mentioned polyol components can be used. Among them, the polyester polyol is preferably produced using an aliphatic polyol.

Examples of the lactone which is a raw material for producing a polyester polyol which can be used for producing a polyurethane include ε-caprolactone, β-methyl-δ-valerolactone and the like.

Examples of the polyether polyols that can be used in the production of polyurethane include polyethylene glycol, polypropylene glycol, polytetramethylene glycol, poly (methyltetramethylene glycol), and one or more of these. Can be used.

Examples of the polycarbonate polyol that can be used for producing the polyurethane include a polycarbonate polyol obtained by reacting the polyol with a carbonate compound such as dialkyl carbonate, diaryl carbonate, or alkylene carbonate. As the polyol which is a raw material for producing a polycarbonate polyol, those exemplified as the polyol which is a raw material for producing a polyester polyol can be used. Dialkyl carbonate includes dimethyl carbonate, diethyl carbonate, and the like, diaryl carbonate includes diphenyl carbonate, and the like, and alkylene carbonate includes ethylene carbonate.

Examples of the polyester polycarbonate polyols that can be used in the production of polyurethane include those obtained by simultaneously reacting a polyol, a polycarboxylic acid and a carbonate compound, and those obtained by reacting a polyester polyol and a polycarbonate polyol prepared in advance with a carbonate compound. And the like.

The number average molecular weight of the high molecular polyol used for producing the polyurethane is preferably from 500 to 10,000, more preferably from 700 to 5,000, and
More preferably, it is 50 to 4000. The number average molecular weight of the high molecular polyol referred to in the present specification is JIS.
It refers to the number average molecular weight calculated based on the hydroxyl value measured according to K1577.

The number of hydroxyl groups per molecule of the high molecular polyol used for the production of polyurethane may be larger than 2 as long as the production of the polyurethane emulsion (A) is not hindered. The polymer polyol having more than 2 hydroxyl groups per molecule is, for example, in the case of a polyester polyol, glycerin, trimethylolpropane, butanetriol, hexanetriol, trimethylolbutane, pentaerythritol, etc. Can be produced by using the polyol as a part of the polyol component.

The organic diisocyanate compound used in the production of the polyurethane is not particularly limited, and known aliphatic diisocyanates, alicyclic diisocyanates, and aromatic diisocyanates having an isocyanate group in the molecule conventionally used in the production of polyurethane emulsions. Any of the diisocyanates can be used. Specific examples of the organic diisocyanate compound that can be used for the production of polyurethane include isophorone diisocyanate, tolylene diisocyanate, 4,4′-diphenylmethane diisocyanate, p
-Phenylene diisocyanate, 1,5-naphthylene diisocyanate, xylylene diisocyanate, hexamethylene diisocyanate, 4,4'-dicyclohexylmethane diisocyanate, 3,3'-dichloro-4,
Examples thereof include 4′-diphenylmethane diisocyanate and hydrogenated xylylene diisocyanate, and one or more of these organic diisocyanates can be used. Among them, isophorone diisocyanate, tolylene diisocyanate, 4,4'-diphenylmethane diisocyanate, and 4,4'-dicyclohexylmethane diisocyanate are preferably used.

As the chain extender used in the production of the polyurethane, any of the chain extenders conventionally used in the production of the polyurethane emulsion can be used. Among them, an active hydrogen atom capable of reacting with an isocyanate group is used in the molecule. A low molecular weight compound having a molecular weight of 400 or less having two or more is preferably used. Such chain extenders include, for example, hydrazine, ethylenediamine, propylenediamine, isophoronediamine, piperazine and derivatives thereof, phenylenediamine, tolylenediamine, xylylenediamine, adipic dihydrazide, isophthalic dihydrazide, hexamethylene diamine, 4 Diamines such as 4,4'-diaminophenylmethane and 4,4'-dicyclohexylmethanediamine; triamines such as diethylenetriamine; ethylene glycol, propylene glycol, 1,4-butanediol, 1,6-hexanediol, 3-methyl -1,5-pentanediol, neopentyl glycol, 1,4-cyclohexanediol, bis- (β-hydroxyethyl) terephthalate,
Diols such as xylylene glycol and 1,4-bis (β-hydroxyethoxy) benzene; amino alcohols such as aminoethyl alcohol and aminopropyl alcohol; and the like, and one or more of these may be used. be able to. Among these, ethylene glycol, isophoronediamine, ethylenediamine, diethylenetriamine and the like are preferably used.

The polyurethane emulsion (A) has a polyurethane skeleton with respect to 100 g of polyurethane in the polyurethane skeleton in view of polymerization stability at the time of emulsion polymerization of the ethylenically unsaturated monomer (B) and easiness of imparting heat-sensitive gelling property. 3-30m
It preferably has mol neutralized carboxyl or sulfonic acid groups. Introduction of a neutralized carboxyl group or sulfonic acid group into the polyurethane skeleton,
As a raw material for producing polyurethane, a compound having a carboxyl group, a sulfonic acid group, or a salt thereof and containing at least one active hydrogen atom such as a hydroxyl group or an amino group is used in combination. This is achieved by neutralization with a basic substance such as a metal hydroxide. Examples of such compounds include carboxylic acid group-containing compounds such as 2,2-bis (hydroxymethyl) propionic acid, 2,2-bis (hydroxymethyl) butyric acid, and 2,2-bis (hydroxymethyl) valeric acid And derivatives thereof; sulfonic acid group-containing compounds such as 1,3-phenylenediamine-4,6-disulfonic acid and 2,4-diaminotoluene-5-sulfonic acid, and derivatives thereof. Further, polyester polyols or polyester polycarbonate polyols obtained by copolymerizing the above compounds can also be used. Among them,
A method in which a polyurethane prepolymer is produced using 2,2-bis (hydroxymethyl) propionic acid, and neutralized by adding a basic substance such as triethylamine, trimethylamine, sodium hydroxide, or potassium hydroxide after completion of the prepolymer reaction. Is preferred.

In the production of the polyurethane, a trifunctional or higher functional polyol such as trimethylolpropane or a trifunctional or higher amine is reacted as required for the purpose of improving solvent resistance, heat resistance, hot water resistance and the like. The polyurethane may have a crosslinked structure.

The polyurethane emulsion (A) used in the present invention can be produced by the same method as that conventionally used for producing a polyurethane emulsion. For example, (1) having an isocyanate group at the terminal Polyurethane prepared by producing a urethane prepolymer and forcibly emulsifying the prepolymer in water with high mechanical shearing force in the presence of an emulsifier, or simultaneously completing the chain extension reaction with a suitable chain extender to increase the molecular weight And (2) a method of producing a self-emulsifying polyurethane using a hydrophilic polymer polyol, and then emulsifying it in water without using an emulsifier to produce a polyurethane emulsion. Can be mentioned. For the emulsification, an emulsifying and dispersing device such as a homomixer and a homogenizer can be used. In this case, the emulsifying temperature is preferably set to 40 ° C. or lower in order to suppress the reaction between the isocyanate group and water.

The polyurethane-based emulsion (A) has the above-mentioned (1) in view of the polymerization stability when the ethylenically unsaturated monomer (B) is emulsion-polymerized in the presence thereof and the ease of imparting the thermosensitive gelling property. The emulsifier in the above method preferably contains 0.5 to 10 g of a surfactant based on 100 g of the polyurethane. Examples of such surfactants include anionic surfactants such as sodium lauryl sulfate, ammonium lauryl sulfate, sodium polyoxyethylene tridecyl ether acetate, sodium dodecyl benzene sulfonate, sodium alkyl diphenyl ether disulfonate, and sodium di (2-ethylhexyl) sulfosuccinate. Surfactants: Nonionic surfactants such as polyoxyethylene nonyl phenyl ether, polyoxyethylene octyl phenyl ether, polyoxyethylene lauryl ether, polyoxyethylene stearyl ether, polyoxyethylene-polyoxypropylene block copolymer, etc. Among these, anionic interfaces such as sodium lauryl sulfate, polyoxyethylene tridecyl ether acetic acid, and ammonium lauryl sulfate Gender agents are preferred.

The composite resin emulsion used in the present invention is produced by emulsion polymerization of an ethylenically unsaturated monomer (B) in the presence of a polyurethane emulsion (A).
The weight ratio of the polyurethane and the ethylenically unsaturated monomer (B) in the polyurethane emulsion (A) is 90 /
10/90/90, preferably 85/15/15/85, and more preferably 80 / 20-20 / 80. When the proportion of the polyurethane is less than 10% by weight, the modulus of elasticity of the composite resin is increased, and the feeling of the obtained leather-like sheet is inferior. On the other hand, when the proportion of the polyurethane exceeds 90% by weight, the weather resistance and hydrolysis resistance of the composite resin are inferior and the cost is high.

As the ethylenically unsaturated monomer (B) used for producing the composite resin emulsion, methyl (meth) acrylate, ethyl (meth) acrylate, (meth)
Butyl acrylate, 2-ethylhexyl (meth) acrylate, lauryl (meth) acrylate, stearyl (meth) acrylate, cyclohexyl (meth) acrylate,
Isobornyl (meth) acrylate, benzyl (meth) acrylate, (meth) acrylic acid, glycidyl (meth) acrylate, dimethylaminoethyl (meth) acrylate,
Diethylaminoethyl (meth) acrylate, 2-hydroxyethyl (meth) acrylate, (meth) acrylic acid 2
-(Meth) acrylic acid derivatives such as hydroxypropyl;
Aromatic vinyl compounds such as styrene, α-methylstyrene and p-methylstyrene; acrylamides such as acrylamide, diacetone acrylamide and methacrylamide; maleic acid, fumaric acid, itaconic acid and derivatives thereof; heterocyclic rings such as vinylpyrrolidone Formula vinyl compound;
Vinyl compounds such as vinyl chloride, acrylonitrile, vinyl ether, vinyl ketone, and vinyl amide; ethylene,
Α-olefins such as propylene, and the like, and one or more of these can be used. Among them, as the ethylenically unsaturated monomer (B), the proportion of the (meth) acrylic acid derivative is preferably 60% by weight or more, and 70% by weight, from the viewpoint of the feeling and weather resistance of the obtained leather-like sheet. More preferably.

Further, the ethylenically unsaturated monomer (B)
Preferably contains a bifunctional or higher polyfunctional ethylenically unsaturated monomer for improving the durability and adjusting the elastic modulus of the obtained composite resin. Such polyfunctional ethylenically unsaturated monomers include ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, triethylene glycol di (meth) acrylate, polyethylene glycol di (meth) acrylate, 1,4-butane Diol di (meth) acrylate,
1,6-hexanediol di (meth) acrylate,
Di (meth) acrylates such as 1,9-nonanediol di (meth) acrylate, neopentyl glycol di (meth) acrylate, dimethylol tricyclodecane di (meth) acrylate and glycerin di (meth) acrylate; trimethylolpropane Tri (meth) acrylates such as tri (meth) acrylate and pentaerythritol tri (meth) acrylate; tetra (meth) acrylates such as pentaerythritol tetra (meth) acrylate; polyfunctional aromatics such as divinylbenzene and trivinylbenzene Vinyl compound; two or more different ethylenically unsaturated bond-containing compounds such as allyl (meth) acrylate and vinyl (meth) acrylate; 2-hydroxy-3
The molecular weight of a 2: 1 addition reaction product of phenoxypropyl acrylate and hexamethylene diisocyanate, a 2: 1 addition reaction product of pentaerythritol triacrylate and hexamethylene diisocyanate, and a 2: 1 addition reaction product of glycerin dimethacrylate and tolylene diisocyanate; 1500 or less urethane acrylates, etc., and one or more of these can be used. The proportion of the polyfunctional ethylenically unsaturated monomer is preferably from 0.1 to 10% by weight, more preferably from 1 to 8% by weight of the ethylenically unsaturated monomer (B).

The addition of the ethylenically unsaturated monomer (B) to the polyurethane-based emulsion (A) can be carried out at once,
Any of continuous and continuous methods may be used, and multi-stage polymerization in which the monomer composition is changed at each polymerization stage or polymerization by a power feed method in which the monomer composition is continuously changed may be performed. In the case of the multi-stage polymerization or the polymerization by the power feed method, the total amount of the bifunctional or higher polyfunctional ethylenically unsaturated monomer is 0.1 to 10% by weight of the total ethylenically unsaturated monomers (B) used for the polymerization. It is preferred that Further, an emulsifier such as a surfactant may be appropriately added during the polymerization of the ethylenically unsaturated monomer (B).

Examples of the polymerization initiator used for the polymerization of the ethylenically unsaturated monomer (B) include, for example, benzoyl peroxide, lauroyl peroxide, dicumyl peroxide, di-tert-butyl peroxide, cumene hydroperoxide, t Oil-soluble peroxides such as -butyl hydroperoxide, diisopropylbenzene hydroperoxide;
Oil-soluble azo compounds such as 2,2'-azobisisobutyronitrile and 2,2'-azobis- (2,4-dimethylvaleronitrile); hydrogen peroxide, potassium persulfate, sodium persulfate, ammonium persulfate, etc. Water-soluble peroxides; water-soluble azo compounds such as azobiscyanovaleric acid and 2,2'-azobis- (2-amidinopropane) dihydrochloride; and one or more of these are used. Can be. Among these, it is preferable to use an oil-soluble initiator such as an oil-soluble peroxide and an oil-soluble azo compound. Further, a redox initiator system using a reducing agent and, if necessary, a chelating agent together with the polymerization initiator may be used. Examples of the reducing agent include formaldehyde alkali metal sulfoxylates such as Rongalit (formaldehyde sodium sulfoxylate); sulfites such as sodium sulfite and sodium hydrogen sulfite; pyrosulfites such as sodium pyrosulfite; sodium thiosulfate and the like Thiosulfates; phosphites such as phosphorous acid and sodium phosphite; pyrophosphites such as sodium pyrophosphite; mercaptans; ascorbic acids such as ascorbic acid and sodium ascorbate; erythorbic acid;
Erythorbic acid salts such as sodium erythorbate; sugars such as glucose and dextrose; and metal salts such as ferrous sulfate and copper sulfate. As a chelating agent,
Examples include sodium pyrophosphate and ethylenediaminetetraacetate. The amounts of these initiators, reducing agents and chelating agents used are determined according to the combination of the respective initiator systems.

The composite resin emulsion used in the present invention may contain another polymer in the emulsion as long as the properties of the obtained leather-like sheet are not impaired.
As such other polymers, for example, acrylonitrile-butadiene copolymer, polybutadiene, synthetic rubber such as polyisoprene, ethylene-propylene copolymer, polyacrylate, acrylic copolymer, silicone, other polyurethane, Examples include elastic synthetic polymers such as polyvinyl acetate, polyvinyl chloride, polyester-polyether block copolymer, and ethylene-vinyl acetate copolymer. The composite resin emulsion can contain one or more of these polymers.

The composite resin emulsion may be used, if necessary,
Further known additives, for example, surfactants such as antioxidants, ultraviolet absorbers, penetrants, thickeners, fungicides, water-soluble polymer compounds such as polyvinyl alcohol and carboxymethyl cellulose, dyes, pigments, filling One or two or more agents, coagulation regulators and the like may be contained.

In the present invention, the method of impregnating the fibrous base material with the composite resin emulsion may be any method as long as it can uniformly impregnate the fibrous base material with the emulsion. A method of dipping a fibrous base material in a composite resin emulsion is preferably employed. Furthermore, after impregnating the fibrous base material with the emulsion, the impregnation amount of the emulsion can be adjusted to an appropriate amount using a press roll, a doctor knife or the like.

Next, the composite resin emulsion impregnated in the fibrous base material is heated and solidified. Examples of the method of heat coagulation of the composite resin emulsion include (1) a method in which a fibrous base material impregnated with the emulsion is coagulated by dipping in a hot water bath at 70 to 100 ° C., and (2) a fiber material impregnated with the emulsion. A method of coagulating by spraying heated steam at 100 to 200 ° C. on the base material, and (3) a method of coagulating the fibrous base material impregnated with the emulsion by directly introducing it into a drying device at 50 to 150 ° C. and drying by dry heat. And the like. Among them, the coagulation method in a warm water bath of the above (1) or the coagulation method using heated steam of the above (2) is preferably adopted from the viewpoint of obtaining a leather-like sheet having a more flexible feel. . In the above methods (1) to (3), the temperature at which the composite resin emulsion is coagulated is set so that the coagulation of the emulsion is promptly completed to prevent uneven distribution of the composite resin in the fibrous base material. The temperature is preferably 10 ° C. or more higher than the thermal gelation temperature. Further, in the case where the coagulation method (1) or (2) is used, subsequently, heat drying or air drying is performed to remove moisture contained in the leather-like sheet.

In the leather-like sheet finally obtained by impregnating the fibrous base material with the composite resin emulsion, coagulating and drying, the amount of the polymer adhered to the leather-like sheet (the composite resin emulsion is When the polymer of the present invention is contained, the total amount of the polymer including the composite resin is preferably 5 to 150% by weight, and more preferably 10 to 100% by weight based on the weight of the fibrous base material. Is more preferred. If the attached amount of the polymer is less than 5% by weight, the obtained leather-like sheet-like material tends to lack a sense of fulfillment and tend to not have a natural leather-like feeling. There is a tendency that the leather-like sheet material to be obtained becomes hard and the texture like natural leather cannot be obtained.

The leather-like sheet obtained as described above is
It is rich in flexibility and at the same time has a good feeling similar to natural leather with a sense of fulfillment, and is no inferior to artificial leather obtained by a conventional wet coagulation method. As a result of observation by an electron microscope of the present inventors, it was observed that in the leather-like sheet obtained in the present invention, the composite resin was solidified in the fibrous base material without restraining the fibers. Therefore, in the leather-like sheet obtained in the present invention, the decrease in flexibility caused by the restraint of the fibers is prevented, and the solidified composite resin particles fill the voids between the fibers of the fibrous base material, and apparently. Due to the increased filling of the resin part of
Compared to a conventional emulsion-impregnated leather-like sheet, a leather-like sheet having a feeling of fulfillment and having an excellent feeling similar to natural leather while maintaining good flexibility can be obtained. I think that the.

The leather-like sheet obtained by the present invention takes advantage of the above-mentioned excellent properties, for example, mattresses, bag lining materials, interlining for clothing, interlining for shoes, cushioning materials, automobiles, trains, aircrafts It can be effectively used for a wide range of applications such as interior materials, wall materials, carpets and the like. Furthermore, by providing a polyurethane layer or the like on one side of the leather-like sheet obtained in the present invention by a known method, it is also suitable as artificial leather with silver used for sports shoes, men's shoes, bags, handbags, school bags, and the like. Can be used.

[0058]

EXAMPLES The present invention will be described below in more detail with reference to examples and the like, but the present invention is not limited to these examples. In the following Examples and Comparative Examples, the heat-sensitive gelation temperature of the emulsion and the 9
The elastic modulus at 0 ° C., α-dispersion, flexibility of the sheet, and feeling were evaluated by the following methods.

[Thermal Gelation Temperature] 10 g of the emulsion was weighed into a test tube, and the temperature was raised while stirring in a constant temperature hot water bath at 90 ° C. to obtain an emulsion when the emulsion lost its fluidity and became a gel. This temperature was defined as the thermosensitive gelling temperature.

[Elastic Modulus at 90 ° C., α-dispersion] A 100 μm thick film obtained by drying the emulsion at 50 ° C. was heat-treated at 130 ° C. for 10 minutes, and then subjected to a viscoelasticity measuring apparatus (FTeo, manufactured by Rheology Co., Ltd.). Spectra "DVE-
V4 ”) at a frequency of 11 Hz and 90 ° C.
Was measured for the elastic modulus (E ') and the α-dispersion temperature (Tα).

[Flexibility] A leather-like sheet was made 10 × 10
cm, and a pure bending tester (“KES-FB2-L” manufactured by KATO TEKKO) with the room temperature at 20 ° C.
The bending rigidity (gfcm ^{2) in the} direction perpendicular to the winding direction of the nonwoven fabric used for producing the leather-like sheet material
/ Cm) as an index of flexibility.

[Bending resistance] A leather-like sheet was 7 × 4.
Cut to 5 cm, flex resistance tester (Bally “Flexometer”) according to JIS-K6545
And a bending test was performed at a temperature of 20 ° C. The surface condition of the sheet was observed every 100,000 times of bending, and the number of times until cracks or holes were formed was measured. When cracking or puncturing did not occur even after 500,000 times, bending resistance was sufficiently good and durability was evaluated as "O".

[Hand] Touch a leather-like sheet by hand,
A case having a natural leather-like texture is judged to be “」 ”, and is harder than natural leather and lacks flexibility, and / or
Or, the case where the feeling of fulfillment was insufficient and did not have the texture of natural leather was judged as "x".

The abbreviations of the compounds used in the text are shown in Tables 1 and 2.

[0065]

[Table 1]

[0066]

[Table 2]

Reference Example 1 << Manufacture of Fibrous Substrate >> Polyethylene terephthalate fiber (single fiber fineness: 2 denier, fiber length: 51 mm, shrinkage ratio in hot water at 70 ° C. 25)
%), Using a card and cross-wrapper
A web of 40 g / m ² was produced. The web was passed through a needle locker room and needle-punched at 700 needles / cm ² , and then immersed in hot water at 70 ° C. for 2 minutes to shrink to 56% of the original area. This was subjected to a pressure treatment at 155 ° C. using a cylinder belt press to obtain a thickness of 1.2 mm.
mm, weight 360 g / m ² and apparent density 0.30 g
/ Cm ³ of nonwoven fabric. Emulsion of silicone-based soft water repellent containing dimethylpolysiloxane ("KF96L" manufactured by Shin-Etsu Chemical Co., Ltd.) and methyl hydrogen polysiloxane ("KF99" manufactured by Shin-Etsu Chemical Co., Ltd.) at a weight ratio of 1: 1 (Solid content 5% by weight), squeezed with a roll, and dried at 130 ° C. for 30 minutes.
A non-woven fabric (hereinafter, referred to as a non-woven fabric) having a weight% thereof was obtained.

Reference Example 2 << Manufacture of Fibrous Substrate >> A general-purpose polyethylene terephthalate fiber (single fiber fineness of 2.5 denier) and a nylon fiber (single fiber fineness of 1.5 denier) were mixed at a weight ratio of 35:65. Entangled nonwoven fabric (1.4 mm thick, apparent density 0.25 g / cm
³ ) impregnated with a 5% by weight aqueous solution of a silicone-based soft water repellent (“Geranex SH” manufactured by Matsumoto Yushi Seiyaku Co., Ltd.)
After squeezing with a roll, the resultant was dried at 130 ° C. for 30 minutes to obtain a nonwoven fabric (hereinafter referred to as a nonwoven fabric) having a silicone-based soft water repellent attached to the nonwoven fabric by 1.0% by weight.

Reference Example 3 << Production of Polyurethane Emulsion >> A three-necked flask was charged with 300.0 g of PMPA2000,
60.87 g of TDI and 7.85 g of DMPA were weighed and stirred at 90 ° C. for 2 hours in a dry nitrogen atmosphere to quantitatively react hydroxyl groups in the system to obtain an isocyanate-terminated prepolymer. After adding 195.4 g of MEK thereto and uniformly stirring, the temperature in the flask was lowered to 40 ° C.
5.92 g of EA was added and stirred for 10 minutes. Next, 7.83 g of sodium lauryl sulfate was used as an emulsifier.
Was dissolved in 285.0 g of distilled water, added to the prepolymer, stirred for 1 minute with a homomixer and emulsified, and immediately thereafter, 6.91 g of DETA and 5.70 of IPDA were obtained.
g was dissolved in 496.4 g of distilled water, and the mixture was stirred for 1 minute with a homomixer to carry out a chain extension reaction. Thereafter, MEK was removed by a rotary evaporator to obtain a polyurethane emulsion having a solid content of 35% by weight (hereinafter, referred to as PU).

Reference Example 4 << Production of Polyurethane Emulsion >> In a three-necked flask, 200.0 g of PHC2000, P
TMG1000 100.0 g, IPDI 80.91
g and 7.38 g of DMPA were weighed, and stirred at 90 ° C. for 2 hours in a dry nitrogen atmosphere to quantitatively react hydroxyl groups in the system to obtain an isocyanate-terminated prepolymer. After adding 203.1 g of MEK and stirring uniformly,
The temperature in the flask was lowered to 40 ° C., 5.57 g of TEA was added, and the mixture was stirred for 10 minutes. Next, 12.21 g of sodium lauryl sulfate as an emulsifier was added to distilled water 29
An aqueous solution dissolved in 8.5 g was added to the prepolymer, and the mixture was emulsified by stirring with a homomixer for 1 minute.
A 1.78 g and IPDA 13.23 g were distilled water 5
An aqueous solution dissolved in 14.1 g was added and mixed with a homomixer.
After stirring for minutes, a chain extension reaction was performed. Thereafter, MEK was removed by a rotary evaporator to obtain a polyurethane emulsion having a solid content of 35% by weight (hereinafter, referred to as PU).

Reference Example 5 << Production of Polyurethane Emulsion >> In a three-necked flask, 300.0 g of PCL2000, T
70.53 g of DI and 10.06 g of DMPA were weighed and stirred at 90 ° C. for 2 hours in a dry nitrogen atmosphere to quantitatively react hydroxyl groups in the system to obtain an isocyanate-terminated prepolymer. After adding 204.4 g of MEK to the mixture and uniformly stirring, the temperature in the flask was lowered to 40 ° C.
EA (7.59 g) was added and the mixture was stirred for 10 minutes. Then sodium lauryl sulfate 12.29 as emulsifier
g of distilled water dissolved in 296.3 g of distilled water was added to the prepolymer, and the mixture was emulsified by stirring with a homomixer for 1 minute, and immediately thereafter, 8.82 g of DETA and 2.57 g of EDA were obtained.
Was dissolved in 521.2 g of distilled water, and the mixture was stirred for 1 minute with a homomixer to carry out a chain extension reaction. Thereafter, MEK was removed by a rotary evaporator to obtain a polyurethane emulsion having a solid content of 35% by weight (hereinafter, referred to as PU).

<< Production of Composite Resin Emulsion and Leather-Like Sheet >> Example 1 240 g of PU obtained in Reference Example 3 and ferrous sulfate heptahydrate (FeSO ₄
・ 7H ₂ O) 0.020 g, potassium pyrophosphate
0.294 g, Rongalit (formaldehyde sodium sulfoxylate dihydrate) 0.451 g, EDT
After 0.020 g of A.2Na and 246 g of distilled water were weighed and heated to 40 ° C., the inside of the system was sufficiently purged with nitrogen.
Then, BA 152.1 g, HDDA 3.14 g,
1.57 g of ALMA and 1.57 g of sodium polyoxyethylene tridecyl ether acetate (anionic emulsifier; "ECT-3NEX" manufactured by Nippon Surfactant)
(Monomer), CHP 0.314 g, E
0.314 g of CT-3NEX and 15.0 g of distilled water
The emulsion (initiator) was dropped from the separate dropping funnel into the flask over 4 hours, and after the dropping was completed, it was kept at 40 ° C. for 30 minutes. Then, 38.4g of MMA, HD
0.78 g of DA and 0.392 g of ECT-3NEX
(Monomer), CHP 0.078 g, E
0.078 g of CT-3NEX and 3.0 g of distilled water
Of the emulsion (initiator) is dropped into the flask over a period of 1 hour and 30 minutes from separate dropping funnels.
At 60 ° C. for 60 minutes to complete the polymerization, the solid content
A% by weight emulsion was obtained. This emulsion 100
4 parts by weight of a nonionic surfactant (Emulgen 109P manufactured by Kao) and 1 part by weight of calcium chloride were blended with respect to parts by weight to obtain an emulsion having a thermosensitive gelling property. The thermal gelation temperature of this emulsion, the elastic modulus at 90 ° C. of the film obtained by drying the emulsion, and the α-dispersion temperature (Tα) were as shown in Table 4.

The nonwoven fabric obtained in Reference Example 1 was immersed in a bath of the above thermosensitive gelling emulsion to impregnate the thermogelling emulsion, taken out of the bath, squeezed with a press roll, and then heated to 90 ° C. In a hot water bath for 1 minute to solidify the thermosensitive gelling emulsion,
It dried in the hot-air dryer of 30 degreeC for 30 minutes, and manufactured the sheet-like material. As shown in Table 4, this sheet was a natural leather-like sheet having flexibility and a sense of fulfillment, and excellent feeling and durability.

[0074] to [Example 2] With the cooling tube flask, PU 480 g obtained in Reference Example 3, ferrous sulfate heptahydrate _{(FeSO 4 · 7H 2 O)} 0.011g, potassium pyrophosphate 0.168g , Rongalit 0.258g,
0.011 g of EDTA · 2Na and 98 g of distilled water
Was weighed and heated to 40 ° C., and the inside of the system was sufficiently purged with nitrogen. Then 95.2 g BA, 11.2 MMA
g, HDDA 5.60 g and ECT-3NEX
1.12 g of the mixture (monomer) and CHP 0.1
An emulsion (initiator) of 68 g, 0.168 g of ECT-3NEX and 10.0 g of distilled water was dropped into the flask from separate dropping funnels over 4 hours, and after completion of the dropping, the mixture was kept at 50 ° C. for 60 minutes. The polymerization is completed and the solid content is 4
A 0% by weight emulsion was obtained. This emulsion 10
Emulgen 109P (4 parts by weight) and calcium chloride (1 part by weight) were added to 0 parts by weight to obtain an emulsion having a thermosensitive gelling property. The thermal gelation temperature of this emulsion, the elastic modulus at 90 ° C. of the film obtained by drying the emulsion, and the α-dispersion temperature (Tα) were as shown in Table 4.

The nonwoven fabric obtained in Reference Example 1 was added to Example 1
The above-mentioned thermosensitive gelling emulsion was impregnated and applied in the same manner as described above to produce a sheet. This sheet is
As shown in Table 4, it was a sheet-like material of natural leather having flexibility and a sense of fulfillment, and excellent in feeling and durability.

Example 3 In the same manner as in Example 1, an emulsion having a thermosensitive gelling property was obtained using the raw materials shown in Table 3. The thermal gelation temperature of this emulsion, the elastic modulus at 90 ° C. of the film obtained by drying the emulsion, and the α-dispersion temperature (Tα) were as shown in Table 4. The nonwoven fabric obtained in Reference Example 2 was immersed in a bath of the above thermogelling emulsion to impregnate the thermogelling emulsion, taken out of the bath, squeezed with a press roll, and then 1.5 kg / cm. Steam having a pressure of ² was sprayed on the whole to solidify the thermosensitive gelling emulsion, and further dried in a hot air dryer at 130 ° C. for 30 minutes to produce a sheet-like material. This sheet is shown in Table 4.
As shown in the above, the sheet was a natural leather-like sheet having flexibility and a sense of fulfillment, and excellent feeling and durability.

Example 4 In the same manner as in Example 1, an emulsion having a thermosensitive gelling property was obtained using the raw materials shown in Table 3. The thermal gelation temperature of this emulsion, the elastic modulus at 90 ° C. of the film obtained by drying the emulsion, and the α-dispersion temperature (Tα) were as shown in Table 4. A commercially available polyester knitted fabric not treated with a soft water repellent (thickness 0.85 mm, apparent density 0.
35 g / cm ³ ) was immersed in the bath of the thermogelling emulsion described above to impregnate the thermogelling emulsion, taken out of the bath, squeezed with a press roll, and then squeezed with a press roll.
The sheet was heated in a hot-air dryer at 30 ° C. for 30 minutes to coagulate and dry to produce a sheet. As shown in Table 4, this sheet was a natural leather-like sheet having flexibility and a sense of fulfillment, and excellent feeling and durability.

Comparative Example 1 In the same manner as in Example 2, as shown in Table 3, an emulsion having a thermosensitive gelling property was obtained using only MMA as a monofunctional ethylenically unsaturated monomer. The thermal gelation temperature, the elastic modulus at 90 ° C. of the film obtained by drying the emulsion and the α-dispersion temperature were as shown in Table 4. The non-woven fabric obtained in Reference Example 1 was impregnated with and applied to the above thermosensitive gelling emulsion in the same manner as in Example 1 to produce a sheet. This sheet was inferior in flexibility because the emulsion used had an elastic modulus at 90 ° C. higher than the range specified in the present invention.

COMPARATIVE EXAMPLE 2 In the same manner as in Example 2, as shown in Table 3, an emulsion having a thermosensitive gelling property was obtained using only BA as a monofunctional ethylenically unsaturated monomer. The thermal gelation temperature, the elastic modulus at 90 ° C. of the film obtained by drying the emulsion and the α-dispersion temperature were as shown in Table 4. Reference Example 1
The heat-sensitive gelling emulsion was impregnated and applied to the nonwoven fabric obtained in the above in the same manner as in Example 1 to produce a sheet. This sheet-like material had good flexibility because the elastic modulus at 90 ° C. of the emulsion used was lower than the range specified in the present invention, but was inferior in fullness.

Comparative Example 3 An emulsion was obtained in the same manner as in Example 1, except that Emulgen 109P and calcium chloride were not added. This emulsion did not exhibit heat-sensitive gelling property, and the film obtained by drying the emulsion had the elastic modulus at 90 ° C. and the α-dispersion temperature shown in Table 4. When the above-mentioned emulsion was impregnated and applied to the nonwoven fabric obtained in Reference Example 1 in the same manner as in Example 1, the emulsion flowed out into a hot water bath and contaminated the bathtub. This sheet-shaped material had a locally hard portion and a nonwoven fabric-like portion without a sense of fullness.

[0081]

[Table 3]

[0082]

[Table 4]

[0083]

According to the production method of the present invention, a leather-like sheet-like material having a natural leather-like feel with significantly improved flexibility and a sense of fulfillment as compared with the conventional emulsion-based resin application can be produced at low cost. Can be manufactured.

Claims (7)

[Claims] The fibrous base material is provided with the following conditions (i) to (ii)
a method for producing a leather-like sheet, characterized by impregnating and coagulating a composite resin emulsion satisfying (i); (i) the composite resin emulsion is heat-sensitive gelling; (ii) the composite resin emulsion Has a modulus of elasticity at 90 ° C. of 1.0 × 10 ^{7 to} 5.0 × 10 ⁸ dyn / cm ² at a film thickness of 100 μm obtained by drying at 50 ° C .; and (iii) the composite resin emulsion However, the amount of the ethylenically unsaturated monomer (B) in the presence of the polyurethane-based emulsion (A) was reduced to 90/10 to 10 by weight of the polyurethane in the polyurethane-based emulsion (A) / the weight of the ethylenically unsaturated monomer (B). This is an emulsion obtained by emulsion polymerization at a ratio of / 90. 2. The leather-like sheet material according to claim 1, wherein the fibrous base material is a material to which a fiber treatment agent having an action of preventing adhesion between the fiber and the composite resin is applied in advance. Production method. 3. A fiber treatment agent having a function of preventing adhesion between a fiber and a composite resin is a flexible water repellent comprising a mixture of dimethylpolysiloxane and methylhydrogenpolysiloxane. 3. The method for producing a leather-like sheet according to item 1. 4. The α-dispersion temperature of a 100 μm-thick film obtained by drying a composite resin emulsion at 50 ° C. is as follows:
The method for producing a leather-like sheet according to any one of claims 1 to 3, wherein the temperature is -10C or less. 5. A composite resin emulsion having a thermal gelation temperature of 30 to 70 ° C., and after impregnating the fibrous base material with the composite resin emulsion, at a temperature 10 ° C. or more higher than the thermal gelation temperature. The method for producing a leather-like sheet according to any one of claims 1 to 4, wherein the composite resin emulsion is coagulated. 6. The nonwoven fabric having an apparent density of 0.25 to 0.50 g / cm ³ , wherein the fibrous base material is formed using shrinkable polyethylene terephthalate fibers as at least one component. The method for producing a leather-like sheet according to any one of claims 1 to 5. 7. A leather-like sheet obtained by the production method according to claim 1.