JP2001192980A - Method for producing leather-like sheet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a leather-like sheet having excellent flexibility, sense of fulfillment and excellent feeling, touch and physical properties extremely approximate to those of natural leather, excellent light resistance, durability and high-class feeling. SOLUTION: This method for producing the leather-like sheet comprises impregnating a fibrous substrate composed of an extra fine fiber forming fiber with a composite resin emulsion satisfying conditions (1-i) the composite resin emulsion has thermosensitive gelling characteristics, (1-ii) the composite resin emulsion is an emulsion obtained by subjecting an ethylenic unsaturated monomer (B) to emulsion polymerization in the presence of a polyurethane-based emulsion (A) and (1-iii) the polyurethane-based emulsion (A) in which at least >=30 wt.% of a polymer polyol component constituting a polyurethane is an amorphous polycarbonate polyol, coagulating the emulsion and making the extra fine fiber forming fiber into an extra fine fiber.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for producing a leather-like sheet. More specifically, the present invention relates to a method for producing a leather-like sheet in which a specific composite resin emulsion is impregnated and solidified in a fibrous base material composed of ultrafine fibers. The leather-like sheet obtained by the method of the present invention has remarkably improved flexibility and a sense of fulfillment as compared with a conventional leather-like sheet obtained by impregnating a fibrous base material with an emulsion resin and then heat-solidifying the resin. It has an excellent texture and touch with a luxurious feeling similar to natural leather, physical properties, dyeing properties, light resistance,
Also has excellent durability.

[0002]

2. Description of the Related Art As a substitute for natural leather (artificial leather),
A sheet in which a resin component such as polyurethane is impregnated into a fibrous base material as a binding agent has been conventionally produced. Even among such sheets, when the fibrous base material is made of ultrafine fibers, it has a good texture similar to natural leather,
Used as so-called high-grade suede artificial leather. Typical production methods are as follows: (1) After applying a resin to a fibrous base material composed of sea-island type mixed spun fibers or composite spun fibers capable of forming ultrafine fibers, the sea component is treated with an organic solvent or an aqueous alkaline solution. A method of dissolving or decomposing and removing island components as ultrafine fibers to convert the fibers constituting the fibrous substrate into ultrafine fibers; and (2) forming a fibrous substrate composed of ultrafine fibers in advance, And a method of applying a resin.

[0003] In the above-mentioned methods for producing artificial leather (1) and (2), as a method of applying a resin such as polyurethane to a fibrous base material, a solution in which a resin component is dissolved in an organic solvent such as dimethylformamide is used. By impregnating the fibrous base material with water and then coagulating in a non-solvent such as water, and drying by impregnating the fibrous base material with a solution in which a resin component is dissolved in an organic solvent or an emulsion dispersed in water. Dry methods for coagulation are known.

[0004] In the case of the above-mentioned wet method, it is possible to obtain a sheet 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. On the other hand, when a resin emulsion is used in the dry method, a sheet can be obtained without using an organic solvent, but a high-quality texture comparable to a leather-like sheet obtained by a wet method is developed. I have not been able to. The reason is that the sheet obtained by the dry method has a hard texture due to the structure in which the resin is entangled with the fiber and strongly constrained in the drying process, and the resin-free gap is smaller than the sheet obtained by the wet method. It can be mentioned that the sense of fulfillment is reduced by the occurrence of extremely large amounts.

In the above-mentioned dry method, in particular, after a resin such as polyurethane is applied to a fibrous base material, sea components are dissolved or decomposed and removed with an organic solvent or an aqueous alkali solution to form ultrafine fibers (1). In the method of (1), the resin tends to enter the ultrafine fiber bundle in the processing step and tends to have a structure in which the fibers are strongly restrained, so that the texture of the obtained leather-like sheet is often hard. In this case, if the amount of the resin adhered is reduced so as not to give a hard texture, the texture becomes less satisfactory.

Further, as the above-mentioned dry method using an emulsion resin, a method of producing a base fabric for synthetic leather by impregnating a fabric with an emulsion mixture of a polyurethane emulsion and a polyacrylate emulsion and subjecting the fabric to hot water treatment (Japanese Unexamined Patent Application Publication No. 55-128078) and a nonwoven fabric including a fiber layer mainly composed of ultrafine fibers having a single fiber fineness of 0.5 denier or less, and an inorganic salt added to an aqueous polyurethane emulsion having an average particle size of 0.1 to 2.0 μm. A method of producing an artificial leather by applying a melt-mixed emulsion and drying by heating (Japanese Patent Laid-Open No. 6-316877) has been proposed. However, the artificial leather obtained by these methods is not sufficiently flexible, full, and the like, and it is difficult to say that the texture is sufficiently improved. Further, after processing a nonwoven fabric of fibers composed of two or more polymers with an aqueous emulsion of polyurethane formed from aliphatic diisocyanate, polytetramethylene glycol and aliphatic diamine, the fibers are partially treated with an aqueous alkali solution or an organic solvent. There has been proposed a method of producing artificial leather by decomposing or dissolving to make it ultrafine (JP-A-9-13287).
No. 6). However, the artificial leather obtained by this method has not been sufficiently improved in terms of flexibility and a sense of fulfillment.

[0007] Therefore, in the production of artificial leather,
Although high-quality artificial leather can be obtained, the wet method, in which productivity is low and the use of an organic solvent is indispensable, is currently exclusively used industrially. However, a method for producing a leather-like sheet represented by the above-mentioned dry method in which an aqueous resin emulsion is impregnated into a fibrous base material and then heat-coagulated,
Since there is no need to use an organic solvent when impregnating the resin into the fibrous base material or coagulating the impregnated resin, it is environmentally friendly,
It is extremely effective in terms of safety of work environment and simplification of process, etc., and development of technology that can produce high-quality leather-like sheet excellent in flexibility and fullness using water-based resin emulsion from this point. Is strongly required.

[0008]

SUMMARY OF THE INVENTION An object of the present invention is to provide a dry method using a resin emulsion, which has a fibrous base material composed of ultrafine fibers, is excellent in flexibility and fullness,
Has a good texture and tactile feel very similar to natural leather,
It is still another object of the present invention to provide a method for producing a suede-like high-quality leather-like sheet having excellent physical properties and a leather-like sheet obtained by the method.

[0009]

Means for Solving the Problems As a result of repeated studies by the present inventors to achieve the above object, a specific heat-sensitive gelling composite resin emulsion was formed on a fibrous base material composed of ultrafine fiber-forming fibers. When the ultrafine fiber-forming fiber is ultrafine after coagulation of the emulsion, it is excellent in flexibility, has a sense of fulfillment, has properties similar to natural leather, and has excellent properties. It was found that a high quality leather-like sheet comparable to the wet method could be obtained. That is, by using the specific heat-sensitive gelling emulsion and by forming the fibrous base material into ultrafine fibers after applying the resin, the resin does not strongly restrain the ultrafine fibers in the fibrous base material, and the appropriate fiber The present invention was found to be able to obtain a high-quality leather-like sheet which is impregnated and solidified in a fibrous base material while maintaining a space, and is excellent in flexibility, fullness, physical properties, dyeability, light resistance and durability. Was completed.

That is, according to the present invention, the following conditions (1-i) to (1-ii) are applied to a fibrous base material comprising ultrafine fiber-forming fibers.
A method for producing a leather-like sheet, comprising impregnating and coagulating a composite resin emulsion satisfying the condition (i) and then ultrafinely forming the ultrafine fiber-forming fibers. (1-i) the composite resin emulsion is thermosensitive gelling; (1-ii) the composite resin emulsion is prepared by adding an ethylenically unsaturated monomer (B) in the presence of a polyurethane emulsion (A) An emulsion obtained by emulsion polymerization in a ratio of 90/10 to 10/90 by weight of the polyurethane / weight of the ethylenically unsaturated monomer (B) in the system emulsion (A); (1-ii)
i) the polyurethane-based emulsion (A) is an emulsion of a polyurethane in which 30% by weight or more of a polymer polyol component constituting the polyurethane is an amorphous polycarbonate polyol;

Further, the present invention provides a method for impregnating a fibrous base material comprising ultrafine fiber-forming fibers with a composite resin emulsion satisfying the following conditions (2-i) to (2-iii) and coagulating the composite resin emulsion. It is a method for producing a leather-like sheet, characterized in that the fiber-forming fibers are made extremely fine. (2-i) the composite resin emulsion is thermosensitive gelling; (2-ii) the composite resin emulsion is prepared by adding an ethylenically unsaturated monomer (B) in the presence of a polyurethane emulsion (A) to a polyurethane. An emulsion obtained by emulsion polymerization in which the weight of the polyurethane in the emulsion (A) / the weight of the ethylenically unsaturated monomer (B) is 90/10 to 10/90, (2-ii)
i) the polyurethane-based emulsion (A) is a polyurethane emulsion having an ethylenically unsaturated group in a side chain of a polyurethane skeleton at a rate of 0.5 mmol or more per 100 g of polyurethane;

Further, the present invention is a leather-like sheet obtained by the above-mentioned production method.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail. The fibrous base material in the present invention may be a fibrous base material having an appropriate thickness and a sense of fulfillment, and made of ultrafine fibers having a soft feel, and the ultrafine fibers conventionally used for leather-like sheets. Various fibrous base materials made of fiber can be used.

As the ultrafine fiber-forming fibers constituting the fibrous base material before impregnation with the composite resin emulsion, mixed fine-spun fibers and / or composite spun fibers composed of two or more kinds of polymer substances are preferable. Used. By dissolving and / or decomposing and removing a part of the polymer material constituting the mixed spun fiber and / or the conjugate spun fiber, and leaving the remaining polymer material in the form of ultrafine fibers, the leather-like sheet is used. The fibrous base material can have an ultrafine fiber structure. As representative examples of the mixed fiber spun fiber and / or the conjugate spun fiber having two or more kinds of high molecular substances, the sea-island type mixed spun fiber and the sea-island type composite spun fiber consisting of two or more kinds of high molecular substances are exemplified. By removing high molecular substances that form the sea component from those fibers using an organic solvent, an aqueous alkaline solution, water, etc., the island component is left in an ultrafine form to form an ultrafine fiber. Can be. The fibrous base material used in the present invention may be formed using only one of the sea-island mixed spun fiber and the sea-island composite spun fiber, or may be formed using both.

Examples of the high molecular substance that can constitute the above-mentioned mixed sea-island type spun fiber or mixed sea-island composite spun fiber include polyamides such as 6-nylon, 6,12-nylon, 6,6-nylon and modified nylon; polyethylene. Polyesters such as terephthalate, polybutylene terephthalate and modified polyester; polyolefins such as polyethylene and polypropylene; polystyrene, polymethacrylate, polyvinyl alcohol, polyvinyl chloride, polyvinylidene chloride, polyurethane elastomer,
Examples thereof include polyamide elastomers and polyester elastomers. From these high-molecular substances, two or more substances having different solubility in organic solvents and the like are selected and combined as a sea component and an island component. A sea-island mixed spun fiber or sea-island composite spun fiber having an ultrafine fiber and capable of remaining in the form of a fiber can be obtained.

Although the ratio of the island component to the sea component in the sea-island mixed spun fiber or the sea-island composite spun fiber having an ultrafine fiber is not particularly limited, generally, the ease of production of the mixed spun fiber or the composite spun fiber is high. From the viewpoints of, for example, ease of ultrafine fiber formation and physical properties of the obtained leather-like sheet, it is preferable that the weight ratio of island component to sea component is 15:85 to 85:15, and 25:75 to 75:25. Is more preferable.
In the case of ultrafine fiber-forming sea-island mixed spun fibers or sea-island composite spun fibers, the number and size of the island components, the state of dispersion of the island components in the sea component, and the like are not particularly limited. Any material can be used as long as the material can be obtained smoothly.

Particularly, the sea component is made of polyethylene and / or polystyrene, and the island component is made of polyamide and / or polystyrene.
Alternatively, using a fibrous base material formed using a sea-island mixed spun fiber or a sea-island composite spun fiber made of polyester, impregnated with a composite resin emulsion and coagulated, and then polyethylene and / or Polystyrene is dissolved and removed using an organic solvent such as aromatic hydrocarbons such as benzene, toluene, and xylene, and halogenated hydrocarbons such as carbon tetrachloride and perchrene, and the polyamide that forms the island component remains in the form of ultrafine fibers. The leather-like sheet obtained by this method is excellent in flexibility and fullness, and has a good texture very close to that of natural leather, so that it can be suitably used as a material for artificial leather.

The fibrous base material used in the present invention may be either a nonwoven fabric and / or a knitted woven fabric, but may be composed of only a nonwoven fabric or a nonwoven fabric having a nonwoven fabric layer on at least one surface side. A laminate of a cloth and / or a knitted fabric (for example, a two-layer structure composed of a nonwoven fabric layer and a knitted fabric layer, a nonwoven fabric layer on the front and back sides and a knitted fabric layer in the center)
Layered structure) is 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.

Further, the fibrous base material used in the present invention may be formed by using other fiber materials together with the above-mentioned ultrafine fibers as needed, as long as the texture of the obtained leather-like sheet is not impaired. Good. Examples of other fiber materials include ordinary fibers, shrinkable fibers, latent spontaneously extensible shrinkable fibers, multilayer-bonded latently splittable fibers, special porous fibers, and the like. The above can be used in combination. These other fibers include synthetic fibers such as polyamide fibers, polyester fibers, acrylic fibers, polyolefin fibers, polyvinyl chloride fibers, polyvinylidene chloride fibers, and polyvinyl alcohol fibers, and semi-synthetic fibers such as rayon. And natural fibers such as cotton, wool and hemp.

The monofilament fineness of the ultrafine fiber forming fibers constituting the fibrous base material after ultrafine fiber formation is 0, since a leather-like sheet having a natural leather-like texture excellent in flexibility and fullness can be obtained. It is preferably not more than 0.5 denier, and 0.4
More preferably, it is not more than denier.

The thickness of the fibrous base material can be arbitrarily selected depending on the intended use of the leather-like sheet to be obtained. However, the thickness of the fibrous base material before impregnation with the composite resin emulsion is preferred in order to give an appropriate leather-like texture. It is preferably from 0.3 to 3.0 mm, more preferably from 0.6 to 2.5 mm.

The apparent density of the fibrous base material is determined in the condition that the fibers in the fibrous base material are in the form of ultrafine fibers (the sea-island mixed spun fiber described above) in view of the flexibility of the obtained leather-like sheet. And / or when the composite spun fiber is used and after removing the sea component to make it into an ultrafine fiber), 0.1 to 0.5 g
/ Cm ³ , preferably 0.15 to 0.45 g /
More preferably, it is cm ³ . If the apparent density of the fibrous base material is less than 0.1 g / cm ³ , the resulting leather-like sheet tends to have poor resilience and low back feeling, making it difficult to obtain a texture like natural leather. On the other hand, when the apparent density of the fibrous base material is larger than 0.5 g / cm ³ , the resulting leather-like sheet tends to have no feeling of stiffness or a poor rubber-like texture.

According to the present invention, in order to uniformly and quickly impregnate the above-mentioned fibrous base material with the emulsion, the surfactant which exhibits wet permeability to the fibrous base material prior to the emulsion impregnation is used. It is also possible to provide an aqueous solution or an aqueous emulsion of. In this case, it is necessary to impregnate the composite resin emulsion without drying and removing the water from the fibrous base material to which the aqueous solution or the aqueous emulsion of the surfactant is applied, and when the drying is completely performed and the water disappears, Can hardly expect any effect. The amount of the surfactant provided to the fibrous base material is preferably 0.01 to 20% by weight based on the fibrous base material.

In the present invention, a fibrous base material composed of ultrafine fiber-forming fibers is impregnated with a heat-sensitive gelling composite resin emulsion and coagulated to produce a leather-like sheet. (2-i)].

The term "thermosensitive gelling emulsion" as used herein means an emulsion which loses fluidity when heated and becomes a gel. The heat-sensitive gelling temperature at which the heat-sensitive gelling composite resin emulsion loses fluidity by heating and gels is preferably 30 to 70 ° C., and more preferably 40 to 70 ° C. If the composite resin emulsion is not thermosensitive gelling, when the fiber substrate is impregnated with the emulsion and dried with hot air, a phenomenon called migration, in which the resin moves to the surface of the fibrous substrate, occurs, and the composite resin becomes a fiber. It is impossible to uniformly disperse the leather-like sheet in the base material, and the physical properties such as the strength and elongation and the flexibility of the leather-like sheet are reduced, and the texture is deteriorated. In addition, when coagulating the emulsion in hot water after impregnating the fibrous base material with the composite resin emulsion, the emulsion may flow out into the hot water and also disperse the composite resin uniformly in the fibrous base material. It becomes impossible to give, and similarly to the above, the physical properties such as the strength and elongation and the flexibility of the leather-like sheet are reduced, and the texture is deteriorated.

The heat-sensitive gelling composite resin emulsion may be an emulsion containing a heat-sensitive gelling composite resin by itself or a heat-sensitive gelling composite resin obtained by adding a heat-sensitive gelling agent to an emulsion. 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, as the heat-sensitive gelling agent, a combination of an inorganic salt and a polyethylene glycol-type nonionic surfactant because of exhibiting good heat-sensitive gelling property, good storage stability and low cost. Is preferably used. As the inorganic salt in that case, a metal salt capable of lowering the cloud point of the polyethylene glycol type nonionic surfactant is preferably used, and examples thereof include sodium carbonate, potassium carbonate, sodium sulfate, calcium sulfate, sodium chloride, and chloride. Potassium, calcium chloride, zinc chloride, aluminum chloride, magnesium chloride,
Examples thereof include sodium nitrate and lead nitrate, and one or more of these can be used. Also,
Examples of the polyethylene glycol type nonionic surfactant include an ethylene oxide adduct of a higher alcohol, an ethylene oxide adduct of an alkyl phenol,
Examples thereof include ethylene oxide adducts of fatty acids, ethylene oxide adducts of fatty acid esters of polyhydric alcohols, ethylene oxide adducts of higher alkylamines, and ethylene oxide adducts of polypropylene glycol. One or more of these may be mentioned. 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 composite resin emulsion used in the present invention is
In the presence of the polyurethane emulsion (A), the ethylenically unsaturated monomer (B) is mixed with the polyurethane and the ethylenically unsaturated monomer (B) in the polyurethane emulsion (A) at a weight ratio of 90/10 to 10/90. [Effects (1-ii) and (2-ii) above]. The weight ratio of the polyurethane to the ethylenically unsaturated monomer (B) is 80/20 to 15
/ 85, more preferably 70/30 to 20/80. When the proportion of the polyurethane is less than 10% by weight, the solvent resistance of the composite resin decreases, and when the sea component of the fiber is extracted with the organic solvent, the thickness of the obtained sheet is reduced by the pressure of the squeezing roll or the like. Since a so-called "set" occurs, the sheet does not become a satisfactory leather-like sheet. When the proportion of the polyurethane emulsion (A) exceeds 90% by weight, it is difficult to put the elastic polymer into practical use because the weather resistance and hydrolysis resistance of the elastic polymer are poor and the cost is high.

The polyurethane emulsion (A) for producing the composite resin emulsion used in the present invention.
Is 3 of the high molecular polyol component constituting polyurethane.
Either 0% by weight or more is an emulsion of a polyurethane which is an amorphous polycarbonate polyol (the above-mentioned condition (1-iii)) or contains an ethylenically unsaturated group in a side chain of the polyurethane skeleton in an amount of 0.1% per 100 g of the polyurethane.
It is necessary that the emulsion has a polyurethane content of 5 mmol or more (the above condition (2-iii)). By using an amorphous polycarbonate polyol as the polymer polyol, fusion between emulsion particles is promoted, and the mechanical properties of the composite resin film are improved. Further, since the ethylenically unsaturated group is present in the side chain of the polyurethane skeleton, the molecular weight of the polyurethane does not decrease, and the ethylenically unsaturated group in the polyurethane skeleton during emulsion polymerization of the ethylenically unsaturated monomer (B). And the ethylenically unsaturated monomer (B) are easily copolymerized, and the resulting composite resin is particularly excellent in solvent resistance and mechanical properties. At least 70% by weight of the high molecular polyol component constituting the polyurethane is amorphous polycarbonate, and the ethylenically unsaturated groups on the side chain of the polyurethane skeleton are polyurethane 1
If the amount is less than 0.5 mmol per 00 g, the elongation of the composite resin decreases, and the physical properties of the obtained leather-like sheet decrease.

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 preferably 5.0 × 10 ⁷ Pa or less, and 3.0. X 107 Pa or less, more preferably 2.0 x 10 ⁷ Pa or less. The elastic modulus at 90 ° C. is 5.0 × 10 ⁷ P
If a composite resin emulsion that gives the dry film exceeding a is used, the resulting sheet will have a hard texture with poor flexibility.

The elastic modulus at 160 ° 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 5.0 × 10 ⁵ P
It is preferably at least a, more preferably at least 8.0 × 10 ⁵ Pa, even more preferably at least 1.0 × 10 ⁶ Pa. The elastic modulus at 160 ° C. is 5.0
When a composite resin emulsion that gives the dry film of less than × 10 ⁵ Pa is used, the fibrous base material is impregnated with the emulsion and solidified, and then the sea-island mixed spun fiber constituting the fibrous base material is used. When the sea component in the conjugate spun fiber is extracted and removed with an organic solvent to form an ultrafine fiber, a so-called “sag” is generated in which the thickness is reduced by receiving pressure from a squeezing roll or the like, and flexibility and fulfillment are obtained. It tends to have bad texture, such as a feeling of waist. The method of measuring the elastic modulus at 90 ° C. and 160 ° C. of the dry film formed from the composite resin emulsion 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), physical properties such as cold resistance and bending resistance of the obtained leather-like sheet are further improved. 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 polyurethane contained in the polyurethane emulsion (A) is generally a polymer polyol,
It can be produced by appropriately combining and reacting an organic polyisocyanate compound and a chain extender.

The above-mentioned high molecular polyol used in the production of polyurethane includes polyester polyol,
Examples thereof include polycarbonate polyols, polyester polycarbonate polyols, and polyether polyols. Polyurethane can be formed by using one or more of these polymer polyols.

Polyester polyols that can be used in the production of polyurethane are prepared by, for example, 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.

Examples of the polycarboxylic acid component which is a raw material for producing a polyester polyol which can be used for producing polyurethane include succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, dodecane diacid, and the like. 2-methylsuccinic acid, 2-methylglutaric acid, 3-methylglutaric acid, 2-methyladipic acid, 3
-Methyladipic acid, 3-methylpentanedioic acid, 2-methyloctanedioic acid, 3,8-dimethyldecandioic acid, 3,
Aliphatic dicarboxylic acids such as 7-dimethyldecandioic acid;
Alicyclic dicarboxylic acids such as 1,4-cyclohexanedicarboxylic acid; aromatic dicarboxylic acids such as isophthalic acid, terephthalic acid, phthalic acid, and naphthalenedicarboxylic acid; tricarboxylic acids such as trimellitic acid and trimesic acid; Derivatives and the like can be mentioned, and the polyester polyol can be formed using one or more of the above-mentioned polycarboxylic acid components. Among them, the polyester polyol is mainly composed of an aliphatic dicarboxylic acid or an ester-forming derivative thereof as a polycarboxylic acid component, and optionally contains a small amount of a trifunctional or more polycarboxylic acid or an ester-forming derivative thereof. It is preferably manufactured.

Examples of the polyol component, which is a raw material for producing a polyester polyol that can be used for producing polyurethane, include ethylene glycol, diethylene glycol, triethylene glycol, 1,2-propanediol, 1,3-propanediol, and 2-methyl- 1,3-
Propanediol, 2,2-diethyl-1,3-propanediol, 1,3-butanediol, 1,4-butanediol, 1,5-pentanediol, 3-methyl-
1,5-pentanediol, neopentyl glycol,
1,6-hexanediol, 1,7-heptanediol, 1,8-octanediol, 2-methyl-1,8-
Aliphatic diols such as octanediol, 2,7-dimethyl-1,8-octanediol, 1,9-nonanediol, 2,8-dimethyl-1,9-nonanediol, 1,10-decanediol; cyclohexanedi Alicyclic diols such as methanol, 1,4-cyclohexanediol and dimethylcyclooctanedimethanol;
Aromatic diols such as bis (β-hydroxyethoxy) benzene; polyalkylene glycol; triols such as glycerin, trimethylolpropane, butanetriol, hexanetriol, trimethylolbutane, and trimethylolpentane; and tetraols such as pentaerythritol. And one or more of the above-mentioned polyol components can be used. Among them, the polyester polyol is preferably made of an aliphatic polyol as a polyol component, and is preferably produced using a polyol component containing a small amount of a trifunctional or higher polyol in some cases.

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

The polycarbonate polyol which can be used for producing polyurethane is obtained, for example, by reacting the polyol with a carbonate compound such as dialkyl carbonate, alkylene carbonate and diaryl carbonate. As the polyol which is a raw material for producing a polycarbonate polyol, the above-mentioned polyols which are raw materials for producing a polyester polyol can be used. Examples of the dialkyl carbonate include dimethyl carbonate and diethyl carbonate, examples of the alkylene carbonate include ethylene carbonate, and examples of the diaryl carbonate include diphenyl carbonate.

Examples of the polyester polycarbonate polyol which 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 previously prepared polyester polyol with a carbonate compound. Examples include those obtained by reacting a previously prepared polycarbonate polyol with a polyol and a polycarboxylic acid, those obtained by reacting a previously prepared polyester polyol and a polycarbonate polyol, and the like. be able to.

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.

The number average molecular weight of the high molecular polyol used in the production of the polyurethane is preferably from 500 to 10,000, more preferably from 700 to 5,000,
More preferably, it is 750 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 in 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 a number of hydroxyl groups per molecule larger than 2 is, for example, in the case of a polyester polyol, the above-mentioned trifunctional or higher functional polycarboxylic acid or polyol is used as a part of a raw material for producing the polyester polyol. Can be manufactured.

As described above, in the high molecular polyol constituting the polyurethane, it is preferable that at least 30% by weight or more of the total high molecular polyol component is an amorphous polycarbonate polyol. The amorphous polycarbonate polyol refers to a polycarbonate polyol which does not exhibit crystallinity and is liquid at room temperature. Such an amorphous polycarbonate polyol is obtained by using a polyol having a branched chain as at least a part of the polyol used for producing the polycarbonate polyol. Further, as an amorphous polycarbonate polyol, the content of the ester group is 20 mol of the content of the carbonate group.
% Or less of an amorphous polyester polycarbonate polyol.

When the proportion of the amorphous polycarbonate polyol in the polymer polyol constituting the polyurethane is less than 30% by weight, an ethylenically unsaturated group is added to the side chain of the polyurethane skeleton at 0.5 mmol per 100 g of the polyurethane. It is necessary to have the above ratio.
The amount of the ethylenically unsaturated group is preferably at least 0.7 mmol per 100 g of polyurethane, more preferably at least 1.0 mmol per 100 g of polyurethane. In order to obtain such a polyurethane,
It is preferable to use a polyol compound having an ethylenically unsaturated group in a side chain together with the above-mentioned polymer polyol. Examples of such a polyol compound having an ethylenically unsaturated group in its side chain include, for example, a 1: 2 adduct of ethylene glycol diglycidyl ether and (meth) acrylic acid, and one of diethylene glycol diglycidyl ether and (meth) acrylic acid. : 2 adduct, 1: 2 adduct of propylene glycol diglycidyl ether and (meth) acrylic acid,
1: 2 adduct of neopentyl glycol diglycidyl ether and (meth) acrylic acid, 1: 2 of 1,6-hexanediol diglycidyl ether and (meth) acrylic acid
Examples thereof include diadducts, 1: 2 adducts of bisphenol A diglycidyl ether and (meth) acrylic acid, and one or more of these can be used.

The kind of the organic polyisocyanate compound used for producing the polyurethane is not particularly limited, and any of the known organic polyisocyanates conventionally used for producing the polyurethane emulsion can be used. Examples of the organic polyisocyanate compound that can be used in the production of polyurethane include hexamethylene diisocyanate, isophorone diisocyanate, 4,4′-dicyclohexylmethane diisocyanate, norbornene diisocyanate, 2,4-tolylene diisocyanate,
Examples thereof include 6-tolylene diisocyanate, 4,4'-diphenylmethane diisocyanate, p-phenylene diisocyanate, xylylene diisocyanate, 1,5-naphthylene diisocyanate, and one or more of these can be used. .

Among the organic polyisocyanate compounds described above, aromatic polyisocyanate compounds such as tolylene diisocyanate and 4,4'-diphenylmethane diisocyanate are preferably used because the resulting polyurethane has excellent solvent resistance. When a polyurethane obtained from an aromatic polyisocyanate compound is used, a fibrous base material composed of sea-island mixed spun fibers and / or composite spun fibers is impregnated with a composite resin emulsion and coagulated, and then coagulated in the fibers. When the components are extracted and removed with an organic solvent to form ultrafine fibers, the composite resin is excellent in solvent resistance, so the deterioration of the physical properties of the composite resin due to the organic solvent is suppressed, and the leather-like sheet is excellent in texture and mechanical properties. Can be obtained.

As the chain extender used in the production of the polyurethane, any of the chain extenders conventionally used in the production of polyurethane emulsions can be used. Among them, an active hydrogen atom capable of reacting with an isocyanate group is used. A low molecular compound having a molecular weight of 400 or less having two or more of them is preferably used. Such chain extenders include
For example, hydrazine, ethylenediamine, propylenediamine, hexamethylenediamine, nonamethylenediamine, xylylenediamine, isophoronediamine, norbornenediamine, 4,4'-diaminodicyclohexylmethane, piperazine and its derivatives, phenylenediamine, tolylenediamine, xylylenediamine Amine, 4,
4'-diaminodiphenylmethane, adipic dihydrazide, isophthalic dihydrazide, N-methyl-3,
Diamines such as 3'-iminobis (propylamine); triamines such as diethylenetriamine; tetraamines such as triethylenetetramine; ethylene glycol, propylene glycol, 1,4-butanediol, 1,6-hexanediol, 1,4 Diols such as -bis (β-hydroxyethoxy) benzene, 1,4-cyclohexanediol, bis- (β-hydroxyethyl) terephthalate, xylylene glycol, N-methyldiethanolamine; triols such as trimethylolpropane; pentaerythritol Tetraols; amino alcohols such as aminoethyl alcohol and aminopropyl alcohol; and one or more of these can be used. Among these, ethylenediamine, isophoronediamine,
Diethylenetriamine, ethylene glycol and the like are preferably used.

The polyurethane-based emulsion (A) is used in an amount of 100 g of polyurethane in the polyurethane skeleton in view of the polymerization stability at the time of emulsion polymerization of the ethylenically unsaturated monomer (B) and the ease of imparting thermosensitive gelling properties. 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. It is achieved by neutralization with a basic substance such as a metal hydroxide.
Such compounds include, for example, 2,2-bis (hydroxymethyl) propionic acid, 2,2-bis (hydroxymethyl) butyric acid, 2,2-bis (hydroxymethyl)
Carboxylic acid group-containing compounds such as 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 And the like. Further, polyester polyols or polyester polycarbonate polyols obtained by copolymerizing the above compounds can also be used. Among them, a polyurethane prepolymer is produced using 2,2-bis (hydroxymethyl) propionic acid and / or 2,2-bis (hydroxymethyl) butyric acid, and after completion of the prepolymer reaction, triethylamine, trimethylamine,
A method of adding a basic substance such as sodium hydroxide or potassium hydroxide for neutralization is preferred.

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) a polymer polyol and an organic polymer A hydrophobic polyurethane prepolymer having an isocyanate group at a terminal obtained by reacting an isocyanate compound,
Simultaneously or after forcibly emulsifying and dispersing in water by high mechanical shearing force in the presence of an emulsifier, or thereafter, a method of reacting a chain extender such as polyamine to increase the molecular weight,
(2) A method in which a hydrophilic polyurethane prepolymer having an isocyanate group at an end into which an ionic group or the like has been introduced is self-emulsified in water, or at the same time, is reacted with a chain extender such as a polyamine to increase the molecular weight. Can be mentioned. Further, in order to facilitate emulsification and dispersion in water, a polyurethane prepolymer having an isocyanate group at a terminal is acetone, methyl ethyl ketone,
It may be diluted with an organic solvent such as toluene, ethyl acetate, tetrahydrofuran or dimethylformamide, and these organic solvents can be removed before or after the emulsion polymerization of the ethylenically unsaturated monomer (B). Further, part or all of the chain extender may be reacted before emulsification of the polyurethane.

The polyurethane emulsion (A) is prepared from the emulsifier according to the above-mentioned method (1) in view of the polymerization stability when the ethylenically unsaturated monomer (B) is emulsion-polymerized and the ease of imparting the thermosensitive gelling property. As polyurethane 10
It is preferable to contain 0.5 to 10 g of surfactant per 0 g. 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 them, sodium lauryl sulfate,
Anionic surfactants such as ammonium lauryl sulfate and sodium polyoxyethylene tridecyl ether acetate 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).
Examples of the ethylenically unsaturated monomer (B) include 90 to 99.9% by weight of a monofunctional ethylenically unsaturated monomer (B1) mainly composed of a (meth) acrylic acid derivative and a bifunctional or higher polyfunctional ethylenically unsaturated monomer (B1). B2) 0.
The content of 1 to 10% by weight is preferred because the texture and weather resistance of the obtained leather-like sheet are further excellent, and the monofunctional ethylenically unsaturated monomer (B1) mainly composed of a (meth) acrylic acid derivative is 92 to 99. 8% by weight and a bifunctional or higher polyfunctional ethylenically unsaturated monomer (B2)
More preferably, it comprises 0.2 to 8% by weight.

The monofunctional ethylenically unsaturated monomer (B1) used in the production of the composite resin emulsion includes:
Methyl (meth) acrylate, ethyl (meth) acrylate, butyl (meth) acrylate, (meth) acrylic acid 2
-Ethylhexyl, lauryl (meth) acrylate, stearyl (meth) acrylate, cyclohexyl (meth) acrylate, isobornyl (meth) acrylate, (meth)
Benzyl acrylate, (meth) acrylic acid, glycidyl (meth) acrylate, dimethylaminoethyl (meth) acrylate, diethylaminoethyl (meth) acrylate,
(Meth) acrylic acid derivatives such as 2-hydroxyethyl (meth) acrylate and 2-hydroxypropyl (meth) acrylate; aromatic vinyl compounds such as styrene, α-methylstyrene and p-methylstyrene; (meth) acrylamide , Diacetone (meth) acrylamide, N- [3
Acrylamides such as-(dimethylamino) propyl] (meth) acrylamide; maleic acid, fumaric acid, itaconic acid and derivatives thereof; heterocyclic vinyl compounds such as vinylpyrrolidone; vinyl chloride, acrylonitrile,
Vinyl compounds such as vinyl ether, vinyl ketone and vinyl amide; and α-olefins such as ethylene and propylene. One or more of these can be used. Among them, as the monofunctional ethylenically unsaturated monomer (B1), the proportion of the (meth) acrylic acid derivative is preferably 60% by weight or more, more preferably 70% by weight or more, and more preferably 80% by weight or more. More preferably, there is.

Bifunctional or higher functional polyfunctional ethylenically unsaturated monomer (B2) used for producing a composite resin emulsion
Examples thereof include ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, triethylene glycol di (meth) acrylate, polyethylene glycol di (meth) acrylate, 1,4-butanediol di (meth) acrylate, and 1,6. Di-hexanediol di (meth) acrylate, 1,9-nonanediol di (meth) acrylate, neopentyl glycol di (meth) acrylate, dimethylol tricyclodecane di (meth) acrylate, glycerin di (meth) acrylate, etc. (Meth) acrylates; Tri (meth) acrylates such as trimethylolpropane tri (meth) acrylate and pentaerythritol tri (meth) acrylate; Tetra such as pentaerythritol tetra (meth) acrylate (Meth) acrylates; polyfunctional aromatic vinyl compounds such as divinylbenzene and trivinylbenzene; two or more different ethylenically unsaturated bond-containing compounds such as allyl (meth) acrylate and vinyl (meth) acrylate; 2-hydroxy -3-phenoxypropyl acrylate and hexamethylene diisocyanate 2: 1 addition reaction product, pentaerythritol triacrylate and hexamethylene diisocyanate 2: 1 addition reaction product, glycerin dimethacrylate and tolylene diisocyanate 2: 1 addition reaction product, etc. Examples thereof include urethane acrylates having a molecular weight of 1500 or less, and one or more of these can be used.

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 and the polymerization by the power feed method, the total amount of the bifunctional or higher polyfunctional ethylenically unsaturated monomer (B2) among the total ethylenically unsaturated monomers (B) used for the polymerization is 0.1 to 0.1%. Preferably, it is 10% by weight. 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 benzoyl peroxide, lauroyl peroxide, dicumyl peroxide, di-t-butyl peroxide, cumene hydroperoxide, and the like. oil-soluble peroxides such as t-butyl hydroperoxide and diisopropylbenzene hydroperoxide; 2,2'-azobisisobutyronitrile, 2,2 '
Oil-soluble azo compounds such as -azobis- (2,4-dimethylvaleronitrile); water-soluble peroxides such as hydrogen peroxide, potassium persulfate, sodium persulfate and ammonium persulfate; azobiscyanovaleric acid, 2,2'- Azobis
Examples thereof include water-soluble azo compounds such as (2-amidinopropane) dihydrochloride, and one or more of these can be used. Among these, oil-soluble peroxides,
It is preferable to use an oil-soluble initiator such as 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 bisulfite; pyrosulfites such as sodium pyrosulfite; sodium thiosulfate Thiosulfate; phosphorous acid,
Phosphites such as sodium phosphite; pyrophosphites such as sodium pyrophosphite; mercaptans; ascorbates such as ascorbic acid and sodium ascorbate; erythorbic acids such as erythorbic acid and sodium erysorbate Sugars such as glucose and dextrose; and metal salts such as ferrous sulfate and copper sulfate. Examples of the chelating agent include sodium pyrophosphate and ethylenediaminetetraacetate. These initiators, reducing agents and chelating agents are used in appropriate amounts depending on the combination of the respective initiator systems.

In the composite resin emulsion used in the present invention, a hindered amino group having a light stabilizing effect and / or an ultraviolet absorbing group can be introduced into the composite resin skeleton in order to improve light resistance. is there. Examples of a method for introducing a hindered amino group and / or an ultraviolet absorbing group having a light stabilizing effect into the composite resin skeleton include, for example, (1) an ethylenically unsaturated monomer (B)
As part of 4- (meth) acryloyloxy-2,
2,6,6-tetramethylpiperidine, 4- (meth) acryloyloxy-1,2,2,6,6-pentamethylpiperidine, 4- (meth) acryloylamino-2,
Hindered amine compounds having an ethylenically unsaturated group such as 2,6,6-tetramethylpiperidine, 4- (meth) acryloylamino-1,2,2,6,6-pentamethylpiperidine, and 2- [2′- Hydroxy-5'-
(Meth) acryloyloxyethylphenyl] -2H-
Benzotriazole, 2-hydroxy-4- (meth) acryloyloxybenzophenone, 2-hydroxy-4
-A method using an ultraviolet absorber having an ethylenically unsaturated group such as (meth) acryloyloxyethylbenzophenone, and (2) 4-hydroxy- as a raw material for producing a polyurethane resin in the polyurethane emulsion (A).
2,2,6,6-tetramethylpiperidine, 4-hydroxy-1,2,2,6,6-pentamethylpiperidine,
1- (2-hydroxyethyl) -4-hydroxy-2,
Polycondensate of 2,6,6-tetramethylpiperidine, 1- (2-hydroxyethyl) -4-hydroxy-2,2,6,6-tetramethylpiperidine and succinic acid, 1- (2
-Hydroxyethyl) -4-hydroxy-2,2,6
Examples include a method using a hindered amine compound having a hydroxyl group such as a polycondensate of 6-tetramethylpiperidine and adipic acid. The amount of the hindered amino group and ultraviolet absorbing group introduced is 0.1 to 5 per 100 g of the composite resin.
0 mmol is preferable from the viewpoint of cost and effect.

The composite resin emulsion used in the present invention may contain other polymers 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, polyisoprene, polyacrylate, acrylic copolymer, olefin copolymer, silicone, other polyurethane, polyvinyl acetate, ethylene -Elastic polymers such as vinyl acetate copolymers, polyvinyl chloride, polyester elastomers and polyamide elastomers. The composite resin emulsion may contain one or more of these polymers.

The composite resin emulsion may be used, if necessary,
Further known additives, for example, light stabilizers, antioxidants, ultraviolet absorbers, surfactants such as penetrants, thickeners,
It may contain one or more of a fungicide, a water-soluble polymer compound such as polyvinyl alcohol and carboxymethyl cellulose, a dye, a pigment, a filler, a coagulation regulator and the like.

The method of impregnating the fibrous base material composed of ultrafine fiber-forming fibers with the composite resin emulsion may be any method as long as the method can uniformly impregnate the fibrous base material with the emulsion. Generally, 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 solidified by heating. 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 immersed in a hot water bath at 70 to 100 ° C. to coagulate, and (2) a fiber impregnated with the emulsion. (3) a method of spraying heated steam at 100 to 200 ° C. onto a fibrous base material to coagulate it, and (3) a method of directly introducing a fibrous base material impregnated with an emulsion into a drying device at 50 to 150 ° C. and coagulating by heating and drying. And the like. Among them, the coagulation method (1) in a hot water bath or the coagulation method (2) using heated steam is preferably employed in that a leather-like sheet having a more flexible texture can be obtained. 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, when the coagulation method described in (1) or (2) above 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, coagulating and drying the fibrous base material with the composite resin emulsion, the amount of the composite resin adhered to the leather-like sheet is determined by the fibrous base material after the formation of the ultrafine fibers. 5 to 1 for weight of material
It is preferably 50% by weight, more preferably 10 to 100% by weight, even more preferably 20 to 80% by weight. If the amount of the composite resin adhered is less than 5% by weight, the obtained leather-like sheet lacks a sense of fulfillment, and a natural leather-like texture cannot be obtained. On the other hand, if it exceeds 150% by weight,
There is a tendency that the obtained leather-like sheet becomes hard and the texture like natural leather cannot be obtained.

In the present invention, a leather-like sheet is produced by impregnating and coagulating a composite resin emulsion and then subjecting the ultrafine fiber forming fibers constituting the fibrous base material to ultrafine fibers. At this time, when the fibrous base material is formed from the above-mentioned mixed sea-island mixed spun fiber and / or mixed sea-island composite spun fiber, after the impregnation and coagulation of the composite resin emulsion, the sea component in the fiber is converted into an organic solvent. Then, the island component is left in an extremely fine fiber state by dissolving and removing using a leather or the like to produce the leather-like sheet of the present invention. In this case, the removal of the sea component with an organic solvent or the like can be performed according to known methods and conditions conventionally used in the production of artificial leather and the like. The step of performing ultrafine fiber formation of the ultrafine fiber forming fiber after coagulation of the composite resin emulsion is to remove the sea component of the sea-island type fiber bound by the composite resin, and to make the ultrafine fiber which is an island component not in contact with the composite resin. As a result,
The resultant leather-like sheet has an effect of weakening the constraint of the composite resin on the fibrous base material composed of ultrafine fibers as a whole.

The leather-like sheet obtained by the method of the present invention is rich in flexibility, at the same time has a sense of fulfillment, has a very good texture similar to natural leather, and can be obtained by a conventional wet coagulation method. There is no inferiority to artificial leather. As a result of observation by an electron microscope of the present inventors, in the leather-like sheet obtained by the method of the present invention, the composite resin does not strongly restrain the fine fibers in the fibrous base material, while leaving an appropriate space between the fine fibers. It was observed that the space between the fibers was filled and solidified. Therefore, in the leather-like sheet of the present invention, a decrease in flexibility caused by binding of the fiber and sagging of the sheet is prevented, and a space between the fibers is filled while leaving a space between the fibers to fill the apparent resin portion. Due to the increased amount, a leather-like sheet having a rich texture and an excellent texture very similar to natural leather can be obtained while maintaining good flexibility compared to conventional emulsion-impregnated leather-like sheets. It is done.

The leather-like sheet of the present invention makes use of the above excellent properties, for example, mattresses, bag lining materials,
Interlining for clothing, interlining for shoes, cushioning materials, cars, trains,
It can be effectively used for a wide range of applications such as interior materials such as aircraft, wall materials, carpets and the like. Further, by brushing, a suede-like leather-like sheet is obtained, which is suitably used as a covering material for clothes, furniture such as chairs and sofas, a covering material for automobiles and trains, a wall material, gloves, and the like. can do. In addition, by applying a polyurethane layer or the like to one surface of the leather-like sheet of the present invention by a known method, it can be suitably used as artificial leather with silver used for sports shoes, men's shoes, bags, handbags, school bags, and the like. Can be.

[0067]

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. and 160 ° C., the temperature of α-dispersion, the feel of the sheet, the physical properties (tensile strength and tear strength), and the fineness of the microfiber 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. and 160 ° C., α Dispersion Temperature] A 100 μm thick film obtained by drying the emulsion at 50 ° C. is heat-treated at 130 ° C. for 10 minutes, and then manufactured by Rheology Co., Ltd. The measurement was performed at a frequency of 11 Hz using a viscoelasticity measuring device FT Rheospectral DVE-V4, and the elastic modulus (E ') at 90 ° C and 160 ° C and the temperature of α dispersion (Tα) were determined.

[Hand] The leather-like sheet is touched with a hand, and a case having a natural leather-like hand is judged as “○”, 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 a natural leather-like texture was judged as “x”.

[Tensile Strength] A leather-like sheet was 12 × 2.5
cm, and the test was conducted at a distance between grips of 5 cm and a tensile speed of 2.5 cm / min according to JIS-L1096, and the maximum tensile stress was defined as tensile strength (N).

[Tear Strength] A leather-like sheet is 10 × 4 cm
And make a 5 cm cut in the center of the short side at right angles to the short side. According to JIS-K6550, the test was performed at a distance between gripping tools of 4 cm and a pulling speed of 10 cm, and the tearing force of the sheet was defined as tearing strength (N). [Fineness of microfiber] From the micrograph of the cross section of the microfiber-forming fiber, the number of island components in one microfiber-forming fiber cross-section was counted, and the fineness of one microfiber bundle after removal of the sea component was determined. Calculate by dividing by

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

[0074]

[Table 1]

[0075]

[Table 2]

<< Production of Fibrous Substrate >> [Reference Example 1] Sea-island mixed spun fiber obtained by mixing and spinning 60 parts of 6-nylon and 40 parts of high-flowable polyethylene, stretching and cutting the mixture. (Single fiber fineness: 4 denier, fiber length: 51 mm, 6-nylon is an island component, number of islands in fiber cross section is 100), and the apparent density is set to 0 through the steps of card, cross wrapper, and needle punch. 160
g / cm ^{3 of} an entangled nonwoven fabric was produced. This non-woven fabric was heated to melt polyethylene as a sea component and heat-set between the fibers to obtain an entangled non-woven fabric having an apparent density of 0.285 g / cm ³ , both surfaces of which were smoothed.

<< Production of Polyurethane Emulsion >> [Reference Example 2] PMHC2000 was placed in a three-necked flask.
50.0 g, 150.0 g of PTMG1400, 2,4
66.62 g of tolylene diisocyanate and 2,
8.18 to 2-bis (hydroxymethyl) propionic acid
g was 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 group-terminated polyurethane prepolymer. After adding 198.4 g of 2-butanone to the mixture and uniformly stirring, 40 ° C.
The temperature in the flask was lowered to 6.17 g of triethylamine.
Was added and stirred for 10 minutes. Then, 4.97 g of sodium lauryl sulfate and ECT-3N were used as emulsifiers.
An aqueous solution in which 4.97 g of EX (anionic emulsifier manufactured by Nippon Surfactant Industry Co., Ltd.) was dissolved in 289.7 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, 6.8 of diethylenetriamine was obtained.
3 g and 1.99 g of ethylenediamine in 50 parts of distilled water.
An aqueous solution dissolved in 4.0 g was added, and the mixture was stirred with a homomixer for 1 minute to perform a chain extension reaction. Thereafter, 2-butanone was removed by a rotary evaporator to obtain a polyurethane emulsion having a solid content of 35 wt% (hereinafter referred to as PU).
). PU is an amorphous polycarbonate polyol in which 50% by weight of the high molecular polyol component constituting the polyurethane has no ethylenically unsaturated group in the side chain of the polyurethane skeleton.

Reference Example 3 PMPA was placed in a three-necked flask.
300.0 g of 2,000, 1.50 g of a 1: 2 adduct of ethylene glycol diglycidyl ether and methacrylic acid (containing two methacryloyl groups in the diol side chain),
61.82 g of 2,4-tolylene diisocyanate and 8.69 g of 2,2-bis (hydroxymethyl) butyric acid
Was weighed and stirred at 90 ° C. for 2 hours in a dry nitrogen atmosphere to quantitatively react hydroxyl groups in the system to obtain a polyurethane prepolymer having an isocyanate group end. After adding 197.1 g of 2-butanone and uniformly stirring, the temperature in the flask was lowered to 40 ° C., and 5.93. G of triethylamine was added.
Was added and stirred for 10 minutes. Next, 9.87 g of sodium lauryl sulfate as an emulsifier was added to 287.5 of distilled water.
g of the aqueous solution added to the prepolymer, and the mixture was emulsified by stirring with a homomixer for 1 minute, and then 6.96 g of diethylenetriamine and 5.74 of isophoronediamine were immediately obtained.
g was dissolved in 500.8 g of distilled water, and the mixture was stirred for 1 minute with a homomixer to perform a chain extension reaction. Thereafter, 2-butanone was removed by a rotary evaporator to obtain a polyurethane emulsion having a solid content of 35 wt% (hereinafter, referred to as PU). PU does not contain an amorphous polycarbonate polyol as a high molecular polyol component constituting the polyurethane, and has an ethylenically unsaturated group in the side chain of the polyurethane skeleton.
It has 2.3 mmol per 00 g.

[Reference Example 4] PMHC was placed in a three-necked flask.
2000: 120.0 g, PTMG1400: 180.
0 g, 0.80 g of a 1: 2 adduct of 1,6-hexanediol diglycidyl ether and methacrylic acid (containing two methacryloyl groups in the diol side chain), 68.09 g of 2,4-tolylene diisocyanate and 2 8.76 g of 2,2-bis (hydroxymethyl) butyric acid is weighed and stirred at 90 ° C. for 2 hours in a dry nitrogen atmosphere to quantitatively react the hydroxyl groups in the system to form a polyurethane prepolymer having an isocyanate group end. Obtained. In addition to this, 2-butanone 199.9
g, and the mixture was stirred uniformly. Then, the temperature in the flask was lowered to 40 ° C., and 5.98 g of triethylamine was added, followed by stirring for 10 minutes. Next, 5.01 g of sodium lauryl sulfate and ECT-3NEX (anionic emulsifier manufactured by Nippon Surfactant Industries, Ltd.) 5.01 as an emulsifier.
g of water dissolved in 291.7 g of distilled water was added to the prepolymer, and the mixture was emulsified by stirring with a homomixer for 1 minute. Immediately, 6.92 g of diethylenetriamine and 5.71 g of isophoronediamine were dissolved in 507.7 g of distilled water. Was added and stirred for 1 minute with a homomixer to carry out a chain extension reaction. Thereafter, 2-butanone was removed by a rotary evaporator to obtain a polyurethane emulsion having a solid content of 35 wt% (hereinafter, referred to as PU). PU is an amorphous polycarbonate polyol in which 40% by weight of a polymer polyol component constituting polyurethane has 1.1 mmol of an ethylenically unsaturated group in a side chain of a polyurethane skeleton per 100 g of polyurethane.

Reference Example 5 In Reference Example 2, 150.
Except that 30.0 g of PMHC2000 and 120.0 g of PHC2000 were used instead of 0 g of PMHC2000, the solid content was 35%.
Thus, a wt% polyurethane emulsion (hereinafter, referred to as PU) was obtained. PU is an amorphous polycarbonate polyol in which 20% by weight of a high molecular polyol component constituting the polyurethane has no ethylenically unsaturated group in a side chain of the polyurethane skeleton.

Reference Example 6 In Reference Example 2, the PMHC
In the same manner as in Reference Example 2 except that 150.0 g of PHC2000 was used instead of
Thus, a wt% polyurethane emulsion (hereinafter, referred to as PU) was obtained. PU does not contain an amorphous polycarbonate polyol as a high molecular polyol component constituting the polyurethane, and has no ethylenically unsaturated group in a side chain of the polyurethane skeleton.

Reference Example 7 In Reference Example 3, the ratio of ethylene glycol diglycidyl ether to methacrylic acid was 1:
A polyurethane emulsion having a solid content of 35 wt% (hereinafter referred to as PU) was obtained in the same manner as in Reference Example 3 except that the amount of the 2 adduct was changed to 0.20 g. PU
Does not contain an amorphous polycarbonate polyol as a polymer polyol component constituting polyurethane, and has 0.3 mmol of ethylenically unsaturated groups in the side chain of the polyurethane skeleton per 100 g of polyurethane.

<< Production of Aqueous Emulsion of Elastic Polymer and Leather-Like Sheet >> [Example 1] In a flask equipped with a cooling tube, 240 g of the PU obtained in Reference Example 2, ferrous sulfate heptahydrate (FeSO4
0.07 g of 7H2O), 0.294 g of potassium pyrophosphate, 0.451 g of Rongalit (formaldehyde sodium sulfoxylate dihydrate), ED
After 0.020 g of TA · 2Na and 234 g of distilled water were weighed and heated to 40 ° C., the inside of the system was sufficiently purged with nitrogen. Next, 167.6 g of BA, 5.29 g of HDDA,
ALMA 3.53 g and ECT-3NEX (anionic emulsifier manufactured by Nippon Surfactant Industries, Ltd.) 1.4
1 g of the mixture (monomer), 0.353 g of CHP,
0.353 g of ECT-3NEX and 27.0 g of distilled water
(Initiator) was dropped into the flask from separate dropping funnels over 5 hours, and after completion of dropping, the mixture was kept at 40 ° C. for 30 minutes. Then, MMA 19.2g, HDD
A mixture (monomer) of 0.392 g of A and 0.157 g of ECT-3NEX, 0.039 g of CHP, ECT
An emulsion (initiator) of 0.039 g of -3NEX and 3.0 g of distilled water was poured into a flask from a separate dropping funnel.
The mixture was added dropwise over 0 minutes, and after completion of the addition, the mixture was maintained at 50 ° C. for 1 hour to complete the polymerization, thereby obtaining an emulsion having a solid content of 40 wt%. To 100 parts by weight of this emulsion, 4 parts by weight of Emulgen 109P (manufactured by Kao, nonionic surfactant) and 1 part by weight of calcium chloride were blended.
An emulsion having heat-sensitive gelling properties was obtained. Thermal gelation temperature of this emulsion, elastic modulus (E ') at 90 ° C and 160 of the film obtained by drying the emulsion
And the temperature of α dispersion (Tα) was 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. Immersed in a hot water bath for 1 minute to solidify the heat-sensitive gelling emulsion.
And dried in a hot air dryer for 30 minutes to produce a sheet. Next, this sheet was immersed in toluene at a temperature of 90 ° C., and squeezed five times with a ² kg / cm ² press roll during the immersion to obtain a sea component in the sea-island mixed spun fiber constituting the nonwoven fabric. (Polyethylene)
A leather-like sheet in which an elastic polymer was impregnated and solidified in a 6-nylon ultrafine fiber bundle entangled nonwoven fabric was produced. The attached weight of the composite resin on the leather-like sheet was 59% by weight based on the weight of the nonwoven fabric after the ultrafine fiber treatment. As shown in Table 4, this sheet was a natural leather-like sheet having excellent texture and physical properties.

Example 2 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, 90 ° C of the film obtained by drying the emulsion and 16 ° C
The elastic modulus and α dispersion temperature at 0 ° C. 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 1.5 kg / cm. Heated steam having a pressure of ² was sprayed on the whole to solidify the thermosensitive gelling emulsion, and further dried in a 130 ° C. hot air drier for 30 minutes to produce a sheet. After that, a microfiber treatment was performed in the same manner as in Example 1 to obtain a leather-like sheet. The attached weight of the composite resin on the leather-like sheet was 56% by weight based on the weight of the nonwoven fabric after the ultrafine fiber treatment. As shown in Table 4, this sheet was a natural leather-like sheet having excellent texture and physical properties.

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, 90 ° C of the film obtained by drying the emulsion and 16 ° C
The elastic modulus and α dispersion temperature at 0 ° C. were as shown in Table 4. In the same manner as in Example 1, the non-woven fabric obtained in Reference Example 1 was impregnated with the above thermosensitive gelling emulsion, applied, and then subjected to an ultrafine fiber treatment to obtain a leather-like sheet. The adhesion weight of the composite of this leather-like sheet was 61% by weight based on the weight of the nonwoven fabric after the ultrafine fiber treatment. As shown in Table 4, this sheet was a natural leather-like sheet having excellent texture and physical properties.

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, 90 ° C of the film obtained by drying the emulsion and 16 ° C
The elastic modulus and α dispersion temperature at 0 ° C. were as shown in Table 4. The above thermosensitive gelling emulsion 100
Polyflow KL-260 is used as a penetrant, based on parts by weight.
(TCS Co., Ltd. substrate wetting agent) After adding 0.5 parts by weight,
After immersing the nonwoven fabric obtained in Reference Example 1 in a bath of this emulsion to impregnate the thermosensitive gelling emulsion,
Remove from bath, squeeze with press roll, then 130 ° C
Was heated in a hot air drier for 30 minutes to coagulate and dry to produce a sheet. After that, a microfiber treatment was performed in the same manner as in Example 1 to obtain a leather-like sheet. The attached weight of the composite resin on the leather-like sheet was 52% by weight based on the weight of the nonwoven fabric after the ultrafine fiber treatment. As shown in Table 4, this sheet was a natural leather-like sheet having excellent texture and physical properties.

[Comparative Example 1] 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, 90 ° C of the film obtained by drying the emulsion and 16 ° C
The elastic modulus and α dispersion temperature at 0 ° C. were as shown in Table 4. In the same manner as in Example 1, the non-woven fabric obtained in Reference Example 1 was impregnated with the above thermosensitive gelling emulsion, applied, and then subjected to an ultrafine fiber treatment to obtain a leather-like sheet. The attached weight of the composite resin on the leather-like sheet was 57% by weight based on the weight of the nonwoven fabric after the ultrafine fiber treatment. As shown in Table 4, this sheet was excellent in texture, but was inferior in physical properties such as tensile strength and tear strength.

Comparative Example 2 In the same manner as in Comparative Example 1, an emulsion having a thermosensitive gelling property was obtained using the raw materials shown in Table 3. Thermal gelation temperature of emulsion, 90 ° C and 160 ° C of film obtained by drying emulsion
The modulus of elasticity and the temperature of α-dispersion were as shown in Table 4. In the same manner as in Example 1, the nonwoven fabric obtained in Reference Example 1 was impregnated with the above thermosensitive gelling emulsion,
After the application, a leather-like sheet was obtained by performing an ultrafine fiber treatment. The attached weight of the composite resin on the leather-like sheet was 59% by weight based on the weight of the nonwoven fabric after the ultrafine fiber treatment. As shown in Table 4, this sheet was excellent in texture, but was inferior in physical properties such as tensile strength and tear strength.

Comparative 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. Thermal gelation temperature of emulsion, 90 ° C and 160 ° C of film obtained by drying emulsion
The modulus of elasticity and the temperature of α-dispersion were as shown in Table 4. In the same manner as in Example 1, the nonwoven fabric obtained in Reference Example 1 was impregnated with the above thermosensitive gelling emulsion,
After the application, a leather-like sheet was obtained by performing an ultrafine fiber treatment. The attached weight of the composite resin on the leather-like sheet was 54% by weight based on the weight of the nonwoven fabric after the ultrafine fiber treatment. As shown in Table 4, this sheet was excellent in texture, but was inferior in physical properties such as tensile strength and tear strength.

Comparative Example 4 An emulsion was obtained in the same manner as in Example 3, except that Emulgen 109P and calcium chloride were not added. This emulsion did not exhibit heat-sensitive gelling properties, and the films obtained by drying the emulsion had the elastic modulus and α-dispersion temperature at 90 ° C. and 160 ° C. as shown in Table 4. When the above-mentioned thermosensitive gelling 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. Next, in the same manner as in Example 3, the nonwoven fabric of this sheet was subjected to ultrafine fiber treatment to produce a leather-like sheet. The attached weight of the composite resin on the leather-like sheet was 31% by weight based on the weight of the nonwoven fabric after the ultrafine fiber treatment. This sheet did not have a paper-like fullness due to sagging as a whole, and had poor physical properties such as tensile strength and tear strength.

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[Table 3]

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[Table 4]

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According to the production method of the present invention, the use of a fibrous base material composed of ultrafine fibers and the application of a resin by an aqueous emulsion of a composite resin provide a natural leather-like texture excellent in flexibility and a sense of fulfillment. A leather-like sheet having excellent physical properties, light resistance and durability can be manufactured at low cost.

Claims (7)

[Claims] 1. A fibrous base material comprising ultrafine fiber-forming fibers is impregnated with a composite resin emulsion satisfying the following conditions (1-i) to (1-iii) and coagulated, and then solidified. A method for producing a leather-like sheet, which comprises making fibers extremely fine. (1-i) the composite resin emulsion is thermosensitive gelling; (1-ii) the composite resin emulsion is prepared by adding an ethylenically unsaturated monomer (B) to a polyurethane-based emulsion (A) in the presence of a polyurethane-based emulsion (A). (1-ii) an emulsion obtained by emulsion polymerization in which the weight of the polyurethane / the weight of the ethylenically unsaturated monomer (B) in the emulsion (A) is 90/10 to 10/90.
i) the polyurethane-based emulsion (A) is a polyurethane emulsion in which 30% by weight or more of the high molecular polyol component constituting the polyurethane is an amorphous polycarbonate polyol; 2. A fibrous base material comprising ultrafine fiber-forming fibers is impregnated with a composite resin emulsion satisfying the following conditions (2-i) to (2-iii) and solidified. A method for producing a leather-like sheet, which comprises making fibers extremely fine. (2-i) the composite resin emulsion is thermosensitive gelling; (2-ii) the composite resin emulsion is prepared by adding an ethylenically unsaturated monomer (B) to a polyurethane-based emulsion (A) in the presence of a polyurethane-based emulsion (A). An emulsion obtained by emulsion polymerization in which the weight of the polyurethane / the weight of the ethylenically unsaturated monomer (B) in the emulsion (A) is 90/10 to 10/90, (2-ii)
i) the polyurethane-based emulsion (A) is a polyurethane emulsion having an ethylenically unsaturated group in a side chain of the polyurethane skeleton at a rate of 0.5 mmol or more per 100 g of polyurethane; 3. A 100 μm-thick film obtained by drying the composite resin emulsion at 50 ° C. has an elastic modulus at 90 ° C. of 5.0 × 10 ⁷ Pa or less, and an elastic modulus at 160 ° C. of 5. The method for producing a leather-like sheet according to claim 1, wherein the pressure is 0 × 10 ⁵ Pa or more. 4. The ethylenically unsaturated monomer (B) comprises 90 to 99.9% by weight of a monofunctional ethylenically unsaturated monomer (B1) mainly composed of a (meth) acrylic acid derivative and a polyfunctional ethylenically unsaturated monomer (B1). B2) 10-0.
The method for producing a leather-like sheet according to any one of claims 1 to 3, comprising 1% by weight. 5. A composite resin which satisfies the above-mentioned conditions (1-i) to (1-iii) and / or (2-i) to (2-iii) on a fibrous base material composed of ultrafine fiber-forming fibers. A method of producing a leather-like sheet by impregnating an emulsion and coagulating the ultrafine fiber-forming fibers to produce ultrafine fibers, wherein the ultrafine fiber-forming fibers are composed of two or more polymer substances. A fiber and / or sea-island mixed spun fiber, wherein the fibrous base material made of the fiber is impregnated with the composite resin emulsion and solidified, and then the sea in the sea-island composite spun fiber and / or sea-island mixed spun fiber The method for producing a leather-like sheet according to any one of claims 1 to 4, wherein ultrafine fibers are formed by removing components. 6. A composite resin emulsion having a thermosensitive gelation temperature of 30 to 70 ° C., and after impregnating the fibrous base material with the composite resin emulsion, at a temperature higher than the thermosensitive gelation temperature by 10 ° C. or more. The method for producing a leather-like sheet according to any one of claims 1 to 5, wherein the composite resin emulsion is coagulated. 7. A leather-like sheet obtained by the production method according to claim 1.