阅读说明：本技术 氨基甲酸酯树脂组合物、发泡氨基甲酸酯片以及合成皮革 (Urethane resin composition, foamed urethane sheet, and synthetic leather ) 是由 藤下章惠 前田亮 于 2020-03-24 设计创作，主要内容包括：本发明提供一种氨基甲酸酯树脂组合物,其特征在于,其含有氨基甲酸酯树脂(A)、水(B)和表面活性剂(C),所述表面活性剂(C)不具有芳香环且具有碳原子数为10以上的疏水部,上述氨基甲酸酯树脂组合物具有来自于氨基甲酸酯树脂(A)的碳酸酯结构(X)和氧亚烷基结构(Y)。另外,本发明提供一种发泡氨基甲酸酯片,其特征在于,其由氨基甲酸酯树脂组合物形成,且密度为200～1,000kg/m～(3)。根据技术方案1所述的氨基甲酸酯树脂组合物,其中,上述碳酸酯结构(X)与上述氧亚烷基结构(Y)的质量比[X/Y]为10/90～90/10的范围。(The present invention provides a urethane resin composition containing a urethane resin (A), water (B), and a surfactant (C) having no aromatic ring and having a hydrophobic portion having 10 or more carbon atoms, wherein the urethane resin composition has a carbonate structure (X) and an oxyalkylene structure (Y) derived from the urethane resin (A). The present invention also provides a foamed urethane sheet which is formed from a urethane resin composition and has a density of 200 to 1,000kg/m 3 . The urethane resin composition according to claim 1, wherein the mass ratio of the carbonate structure (X) to the oxyalkylene structure (Y) [ X/Y ]]Is in the range of 10/90-90/10.)

1. A urethane resin composition comprising a urethane resin (A), water (B), and a surfactant (C) having no aromatic ring and having a hydrophobic moiety having 10 or more carbon atoms, wherein the urethane resin composition has a carbonate structure (X) and an oxyalkylene structure (Y) derived from the urethane resin (A).

2. The urethane resin composition according to claim 1, wherein a mass ratio [ X/Y ] of the carbonate structure (X) to the oxyalkylene structure (Y) is in a range of 10/90 to 90/10.

3. The urethane resin composition according to claim 1 or 2, wherein the surfactant (C) is a stearate.

4. The urethane resin composition according to any one of claims 1 to 3, wherein the urethane resin (A) has an anionic group.

5. A foamed urethane sheet formed from the urethane resin composition according to any one of claims 1 to 4 and having a density of 200kg/m³～1,000kg/m³。

6. A synthetic leather, characterized in that it has at least a substrate (i) and a polyurethane layer (ii),

the polyurethane layer (ii) is formed of the foamed urethane sheet described in claim 5.

Technical Field

The present invention relates to a urethane resin composition, a foamed urethane sheet, and a synthetic leather.

Background

Polyurethane resins have been used for various applications such as coating agents and adhesives because of their excellent mechanical strength and flexibility. Among them, solvent-based urethane resins containing Dimethylformamide (DMF) have been widely used so far, but the legal regulations on DMF are strict year by year, and development of products coping with the environment, such as weak solvent, aqueous solvent, and no solvent, is urgent.

Among them, water-based urethanes (PUDs) in which urethane resins are dispersed in water have been most actively studied. When the aqueous urethane is used for various applications, there is a great demand for a foam molded with the purpose of improving the texture or the like. As a method for molding a foam using an aqueous urethane, for example, a method of blending microcapsules or mechanical foaming in which a gas such as carbon dioxide is dispersed in a PUD blending liquid has been studied (for example, see patent document 1). However, in the method of blending microcapsules, the obtained foam has a problem of poor texture or poor smoothness due to swelling of the microcapsules. In addition, in the method of dispersing a gas, since bubbles mixed in a compounding liquid disappear during the production of a foam, it is difficult to control the bubble size and the like, and it is difficult to stably obtain a foam having a good texture.

In addition to the hand feeling, in recent years, there has been a high demand for resistance to oleic acid contained in human sebum and low-temperature flexibility that can withstand practical use at low temperatures, and it has been difficult to satisfy these required characteristics in a trade-off relationship.

Documents of the prior art

Patent document

Patent document 1: japanese laid-open patent publication No. 2007-191810

Disclosure of Invention

Problems to be solved by the invention

The present invention addresses the problem of providing a urethane resin composition having excellent hand, oil and acid resistance, and low-temperature flexibility, using a water-containing urethane resin composition.

Means for solving the problems

The present invention provides a urethane resin composition containing a urethane resin (A), water (B), and a surfactant (C) having no aromatic ring and having a hydrophobic portion having 10 or more carbon atoms, wherein the urethane resin composition has a carbonate structure (X) and an oxyalkylene structure (Y) derived from the urethane resin (A).

The present invention also provides a foamed urethane sheet which is formed from a urethane resin composition and has a density of 200 to 1,000kg/m³. The present invention also provides a synthetic leather comprising at least a base material (i) and a polyurethane layer (ii), wherein the polyurethane layer (ii) is formed from the foamed urethane sheet.

ADVANTAGEOUS EFFECTS OF INVENTION

The urethane resin composition of the present invention is excellent in hand, resistance to oil acids, and low-temperature flexibility, using a water-containing urethane resin composition.

Detailed Description

The urethane resin composition of the present invention contains a urethane resin (A), water (B), and a surfactant (C) having no aromatic ring and having a hydrophobic portion having 10 or more carbon atoms, and has a carbonate structure (X) and an oxyalkylene structure (Y) derived from the urethane resin (A).

The urethane resin (a) can be dispersed in water (B) described later, and for example, a urethane resin having a hydrophilic group such as an anionic group, a cationic group, or a nonionic group; urethane resin forcibly dispersed in water (B) with an emulsifier. These urethane resins (a) may be used alone, or 2 or more thereof may be used in combination. Among these, from the viewpoint of production stability, a urethane resin having a hydrophilic group is preferably used, and a urethane resin having an anionic group is more preferably used.

Examples of the method for obtaining the urethane resin having an anionic group include a method using 1 or more compounds selected from a diol compound having a carboxyl group and a compound having a sulfonyl group as raw materials.

Examples of the diol compound having a carboxyl group include 2, 2-dimethylolpropionic acid, 2-dimethylolbutyric acid, 2-dimethylolpropionic acid, and 2, 2-dimethylolpentanoic acid. These compounds may be used alone, or 2 or more of them may be used in combination.

Examples of the compound having a sulfonyl group include 3, 4-diaminobutanesulfonic acid, 3, 6-diamino-2-toluenesulfonic acid, 2, 6-diaminobenzenesulfonic acid, and N- (2-aminoethyl) -2-aminoethanesulfonic acid. These compounds may be used alone, or 2 or more of them may be used in combination.

The amount of the raw materials used for producing the urethane resin having an anionic group is preferably in the range of 0.1 to 4.8% by mass, more preferably in the range of 0.5 to 4% by mass, and still more preferably in the range of 1 to 3% by mass of the total mass of the raw materials of the urethane resin (a) from the viewpoint of obtaining more excellent water dispersion stability.

The carboxyl group and the sulfonyl group may be partially or entirely neutralized with a basic compound in the urethane resin composition. Examples of the basic compound include organic amines such as ammonia, triethylamine, pyridine, and morpholine; alkanolamines such as monoethanolamine and dimethylethanolamine; and metal alkali compounds containing sodium, potassium, lithium, calcium, and the like.

Examples of the method for obtaining the urethane resin having a cationic group include a method using 1 or 2 or more of the compounds having an amino group as a raw material.

Examples of the compound having an amino group include compounds having a primary amino group and a secondary amino group such as triethylenetetramine and diethylenetriamine; and compounds having a tertiary amino group such as N-alkyldialkanolamines such as N-methyldiethanolamine and N-ethyldiethanolamine, N-alkyldiaminoalkylamines such as N-methyldiaminoethylamine and N-ethyldiaminoethylamine. These compounds may be used alone, or 2 or more of them may be used in combination.

The urethane resin composition of the present invention has a carbonate structure (X) and an oxyalkylene structure (Y) derived from the urethane resin (a), and thus can provide excellent resistance to oil acids and low-temperature flexibility. The carbonate structure (X) and the oxyalkylene structure (Y) may be supplied from 1 kind of urethane resin (a), or may be supplied from 2 or more kinds of urethane resins (a). The carbonate structure (X) [ O-CO-O ]]Derived from the polycarbonate polyol (a2-1) described later, the oxyalkylene structure (Y) [ O-CH ]₂-CH₂]Derived from the polyether polyol (a2-2) described later.

The mass ratio [ X/Y ] of the carbonate structure (X) to the oxyalkylene structure (Y) is preferably in the range of 10/90 to 90/10, more preferably in the range of 10/90 to 60/40, from the viewpoint of maintaining an excellent hand feeling and satisfying both of the oil resistance and the low-temperature bending resistance at a high level.

Further, the mass ratio [ X/Y ] is preferably in the range of 10/90 to 90/10, more preferably in the range of 10/90 to 60/40, when the carbonate structure (X) and the oxyalkylene structure (Y) are supplied from 1 kind of urethane resin (A).

Further, the mass ratio [ X/Y ] is preferably in the range of 10/90 to 90/10, more preferably in the range of 10/90 to 60/40, when the carbonate structure (X) and the oxyalkylene structure (Y) are each provided by 2 or more kinds of urethane resins (A). In this case, the carbonate structure (X) and the oxyalkylene structure (Y) represent the total sum supplied from 2 or more kinds of urethane resins (a).

The carbonate structure (X) and the oxyalkylene structure (Y) are preferably supplied from 1 type of urethane resin (a) from the viewpoint of obtaining more excellent low-temperature flexibility.

As the urethane resin (a), specifically, for example, a reaction product of a polyisocyanate (a1), a polyol (a2) and a raw material for producing the urethane resin having a hydrophilic group can be used.

Examples of the polyisocyanate (a1) include aromatic polyisocyanates such as phenylene diisocyanate, toluene diisocyanate, diphenylmethane diisocyanate, xylylene diisocyanate, naphthalene diisocyanate, polymethylene polyphenyl polyisocyanate, and carbodiimide diphenylmethane polyisocyanate; aliphatic or alicyclic polyisocyanates such as hexamethylene diisocyanate, lysine diisocyanate, cyclohexane diisocyanate, isophorone diisocyanate, dicyclohexylmethane diisocyanate, xylylene diisocyanate, tetramethylxylylene diisocyanate, dimer acid diisocyanate, and norbornene diisocyanate. These polyisocyanates may be used alone, or 2 or more kinds may be used in combination.

The amount of the polyisocyanate (a1) used is preferably in the range of 5 to 40% by mass, more preferably 10 to 30% by mass, based on the total mass of the raw materials of the urethane resin (a), from the viewpoints of production stability and mechanical properties of the resulting film.

As the above polyol (a2), polycarbonate polyol (a2-1) and polyether polyol (a2-2) are essential materials. In addition, for example, polyester polyol, polyacrylic polyol, polybutadiene polyol, and the like can be used. These polyhydric alcohols may be used alone, or 2 or more kinds may be used in combination.

As the polycarbonate polyol (a2-1), for example, a reaction product of a carbonate and/or phosgene and a compound having 2 or more hydroxyl groups can be used.

Examples of the carbonate include dimethyl carbonate, diethyl carbonate, diphenyl carbonate, ethylene carbonate, and propylene carbonate. These compounds may be used alone, or 2 or more of them may be used in combination.

Examples of the compound having 2 or more hydroxyl groups include ethylene glycol, propylene glycol, 1, 3-propanediol, 1, 4-butanediol, 1, 3-butanediol, 1, 2-butanediol, 2-methyl-1, 3-propanediol, 1, 5-pentanediol, neopentyl glycol, 1, 6-hexanediol, 1, 5-hexanediol, 3-methyl-1, 5-pentanediol, 1, 7-heptanediol, 1, 8-octanediol, 1, 9-nonanediol, 1, 8-nonanediol, 2-ethyl-2-butyl-1, 3-propanediol, 1, 10-decanediol, 1, 12-dodecanediol, 1, 4-cyclohexanedimethanol, 1, 3-cyclohexanedimethanol, Trimethylolpropane, trimethylolethane, glycerol, etc. These compounds may be used alone, or 2 or more of them may be used in combination.

As the polyether polyol (a2-2), a polyoxyalkylene polyol; and those obtained by ring-opening polymerization of cyclic ethers such as alkylene oxides using 1 or 2 or more of compounds having 2 or more active hydrogen atoms as an initiator.

Examples of the polyoxyalkylene polyol include polyoxyethylene glycol, polyoxypropylene glycol, polyoxytetramethylene glycol, polyoxyethylene polyoxypropylene glycol, polyoxyethylene polyoxytetramethylene glycol, polyoxypropylene polyoxytetramethylene glycol, and the like. Among them, from the viewpoint of obtaining more excellent low-temperature flexibility, polyoxypropylene glycol and/or polyoxytetramethylene glycol are preferable, and polyoxytetramethylene glycol is more preferable.

The cyclic ether preferably has 2 to 10 carbon atoms, more preferably 2 to 6 carbon atoms, and still more preferably 2 to 4 carbon atoms. The hydrogen atom contained in the above cyclic ether may be substituted with a halogen atom. The cyclic ether may be 1 or 2 or more, and for example, ethylene oxide, propylene oxide, 1, 2-epoxybutane, 2, 3-epoxybutane, styrene oxide, epichlorohydrin, tetrahydrofuran, alkylated tetrahydrofuran, or the like may be used.

The initiator may be 1 or 2 or more species, and for example, a compound having 2 active hydrogen atoms such as ethylene glycol, diethylene glycol, propylene glycol, trimethylene glycol, 1, 3-butanediol, 1, 4-butanediol, 1, 6-hexanediol, neopentyl glycol, and water; and compounds having 3 or more active hydrogen atoms such as glycerin, diglycerin, trimethylolethane, trimethylolpropane, hexanetriol, monoethanolamine, diethanolamine, triethanolamine, ethylenediamine, pentaerythritol, and saccharides.

The polyether polyol (a2-2) may contain an oxyalkylene structure (Y), and a polyether polyester polyol having an ester bond introduced thereinto may be used.

The number average molecular weight of the polyol (a2) is preferably in the range of 500 to 8,000, more preferably 800 to 4,000, from the viewpoint of mechanical strength of the obtained coating film. The number average molecular weight of the polyol (a2) is a value measured by a gel permeation column chromatography (GPC) method.

The polyol (a2) may be used in combination with a chain extender (a 2') having a number average molecular weight of 50 to 450, if necessary. Examples of the chain extender (a2 ') include chain extenders having a hydroxyl group such as ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, dipropylene glycol, 1, 3-propanediol, 1, 3-butanediol, 1, 4-butanediol, hexamethylene glycol, sucrose, methylene glycol, glycerin, sorbitol, bisphenol a, 4 ' -dihydroxybiphenyl, 4 ' -dihydroxydiphenyl ether, and trimethylolpropane; and chain extenders having an amino group such as ethylenediamine, 1, 2-propylenediamine, 1, 6-hexamethylenediamine, piperazine, 2, 5-dimethylpiperazine, isophoronediamine, 1, 2-cyclohexanediamine, 1, 3-cyclohexanediamine, 1, 4-cyclohexanediamine, 4 ' -dicyclohexylmethanediamine, 3 ' -dimethyl-4, 4 ' -dicyclohexylmethanediamine, 1, 4-cyclohexanediamine, and hydrazine. These chain extenders may be used alone, or 2 or more of them may be used in combination.

The amount of the chain extender (a 2') used is preferably in the range of 0.5 to 10% by mass, more preferably in the range of 1 to 5% by mass, and still more preferably in the range of 1.5 to 4% by mass of the total mass of the raw materials of the urethane resin (a), from the viewpoint of easily adjusting the flow initiation temperature of the obtained urethane resin (a) and obtaining more excellent tensile strength.

Examples of the method for producing the urethane resin (a) include a method in which the polyol (a2), the raw material for producing the urethane resin having a hydrophilic group, the chain extender (a 2'), and the polyisocyanate (a1) are all charged and reacted. Examples of the reaction include a reaction at 50 to 100 ℃ for 3 to 10 hours.

The molar ratio [ isocyanate group/(hydroxyl group and amino group) ] of the total of the hydroxyl group of the polyol (a2), the hydroxyl group and amino group of the raw material for producing the hydrophilic group-containing urethane resin, and the hydroxyl group and amino group of the chain extender (a 2') to the isocyanate group of the polyisocyanate (a1) in the production of the urethane resin (a) is preferably in the range of 0.8 to 1.2, more preferably in the range of 0.9 to 1.1.

In the production of the urethane resin (a), it is preferable to deactivate the isocyanate groups remaining in the urethane resin (a). When the isocyanate group is inactivated, an alcohol having 1 hydroxyl group such as methanol is preferably used. The amount of the alcohol used is preferably in the range of 0.001 to 10 parts by mass per 100 parts by mass of the urethane resin (a).

In addition, an organic solvent may be used in the production of the urethane resin (a). Examples of the organic solvent include ketone compounds such as acetone and methyl ethyl ketone; ether compounds such as tetrahydrofuran and dioxane; acetate compounds such as ethyl acetate and butyl acetate; nitrile compounds such as acetonitrile; amide compounds such as dimethylformamide and N-methylpyrrolidone. These organic solvents may be used alone, or 2 or more of them may be used in combination. The organic solvent is preferably removed by distillation or the like when obtaining the final urethane resin composition.

The flow initiation temperature of the urethane resin (a) is preferably 80 ℃ or higher, and more preferably 80 to 220 ℃ from the viewpoint of stably maintaining the foam generated in the foaming step (particularly in the drying step) described later and stably setting the density of the foamed urethane sheet to a preferable range.

Examples of the method for adjusting the flow initiation temperature of the urethane resin (a) include a method of adjusting the flow initiation temperature mainly in accordance with the kind of the polyol (a2) which is a raw material of the urethane resin (a) described later, the amount of the chain extender (a 2'), and the kind of the polyisocyanate (a 1). Examples of the method for adjusting the flow initiation temperature to a high level include using a polyol having high crystallinity such as a polycarbonate polyol as the polyol (a2), increasing the amount of the chain extender (a2 '), and using a polyisocyanate having high crystallinity such as dicyclohexylmethane diisocyanate or 4, 4' -diphenylmethane diisocyanate as the polyisocyanate (a 1). Examples of the method for adjusting the flow initiation temperature to a low value include using a polyol having low crystallinity such as polyoxypropylene as the polyol (a2), reducing the amount of the chain extender (a 2'), and using a polyisocyanate having low crystallinity such as isophorone diisocyanate or toluene diisocyanate as the polyisocyanate (a 1). Therefore, by appropriately selecting these methods, the flow initiation temperature of the urethane resin (a) can be adjusted. The method for measuring the flow initiation temperature of the urethane resin (a) is described in examples described later.

In the case of using a urethane resin having an anionic group as the urethane resin (a), it is preferable to use a urethane resin (a-1) having an anionic group, which is a reaction product of 1 or more polyisocyanates selected from the group consisting of 4,4 '-diphenylmethane diisocyanate, tolylene diisocyanate, cyclohexylmethane diisocyanate and isophorone diisocyanate, a polyol (a2), a diol compound having a carboxyl group, and a chain extender containing a chain extender (a 2') having a hydroxyl group, in view of easy adjustment of flow initiation temperature and obtaining more excellent foam retention and texture.

As the water (B), for example, ion-exchanged water, distilled water, or the like can be used. These water may be used alone, or 2 or more kinds thereof may be used.

The mass ratio [ (a)/(B) ] of the urethane resin (a) to the water (B) is preferably in the range of 10/80 to 70/30, more preferably in the range of 20/80 to 60/40, from the viewpoints of water dispersion stability and workability.

In order to prevent the disappearance of bubbles (bubble retention) due to foaming and to obtain an excellent texture, the surfactant (C) must have a hydrophobic portion having 10 or more carbon atoms and no aromatic ring.

As the surfactant (C), for example, a surfactant represented by the following general formula (1); fatty acid salts, succinic acid salts, sulfosuccinic acid salts, octadecyl sulfosuccinic acid salts, sulfosuccinic acid esters, and the like. These surfactants may be used alone, or 2 or more of them may be used in combination.

RCO₂·X⁺ (1)

(in the formula (1), R represents an alkyl group having a linear or branched structure and having 10 to 20 carbon atoms, and X represents Na, K, or NH₄Morpholine, ethanolamine, or triethanolamine. )

Among the above surfactants (C), the surfactant represented by the above general formula (1) is preferably used from the viewpoint of more excellent foam retainability, more preferably a surfactant having a linear alkyl group having 13 to 19 carbon atoms is used, and still more preferably a stearate.

The amount of the surfactant (C) used is preferably in the range of 0.01 to 10 parts by mass, and more preferably in the range of 0.1 to 5 parts by mass, per 100 parts by mass of the urethane resin (a) (═ solid content), in view of obtaining more excellent foam retention.

The urethane resin composition contains the urethane resin (a), water (B) and a surfactant (C) as essential components, but may contain other additives as needed.

Examples of the other additives include a crosslinking agent, a neutralizing agent, a thickener, a urethane catalyst, a filler, a pigment, a dye, a flame retardant, a leveling agent, and an antiblocking agent. These additives may be used alone, or 2 or more of them may be used in combination.

The crosslinking agent is used for the purpose of improving the mechanical strength of the foamed urethane sheet, and examples thereof include a polyisocyanate crosslinking agent, an epoxy crosslinking agent, a melamine crosslinking agent, and an oxazoline crosslinking agent. These crosslinking agents may be used alone, or 2 or more kinds may be used in combination. The amount of the crosslinking agent used is, for example, preferably 0.01 to 100 parts by mass, more preferably 0.1 to 50 parts by mass, still more preferably 0.5 to 30 parts by mass, and particularly preferably 1 to 10 parts by mass, based on 100 parts by mass of the urethane resin (a) (═ solid content).

Next, a method for producing the foamed urethane sheet of the present invention will be described.

The foamed urethane sheet is produced by foaming the urethane resin composition to obtain a foaming liquid, applying the foaming liquid to a substrate, and drying the substrate to obtain a preferable density.

Examples of a method for obtaining a foaming liquid by foaming the urethane resin composition include a method using a mixer such as a mechanical mixer or a method using stirring by hand. When a mixer is used, for example, the mixture is stirred at 500 to 3,000rpm for 10 seconds to 3 minutes. In this case, from the viewpoint of easily adjusting the density of the foamed urethane sheet to a preferable range, the volume is preferably 1.3 to 7 times, more preferably 1.2 to 2 times, and still more preferably 1.3 to 1.7 times before and after foaming.

Examples of a method for applying the obtained foaming liquid to a base material such as release paper include a method using a roll coater, a knife coater, a comma coater, an applicator, or the like.

Examples of the method for drying the coated product include a method of drying at a temperature of 60 to 130 ℃ for 30 seconds to 10 minutes.

The thickness of the foamed urethane sheet obtained by the above method is, for example, 5 to 200 μm.

The density of the foamed urethane sheet is preferably 200 to 1,000kg/m from the viewpoint of obtaining more preferable hand and tensile strength³More preferably 300 to 900kg/m³More preferably 400 to 800kg/m³The range of (1). The density of the foamed urethane sheet is a value calculated by dividing the mass of the foamed urethane sheet by the volume.

Next, the synthetic leather of the present invention will be explained.

The synthetic leather of the present invention is a synthetic leather having at least a substrate (i) and a polyurethane layer (ii), wherein the polyurethane layer (ii) is formed of the foamed urethane sheet.

Examples of the method for producing the synthetic leather include:

(X) a method of foaming the urethane resin composition to obtain a foaming liquid, applying the foaming liquid on a release paper, drying the release paper, and bonding the release paper to the substrate (i),

(Y) a method of foaming the urethane resin composition to obtain a foaming liquid, applying the foaming liquid to a skin-like layer formed on a release paper, drying the skin-like layer, and bonding the skin-like layer to the substrate (i),

(Z) a method in which the urethane resin composition is foamed to obtain a foamed liquid, the foamed liquid is applied to the substrate (i), dried, and if necessary, a skin-like layer (iii) produced on a release paper is bonded thereto.

Examples of the substrate (i) include fibrous substrates such as nonwoven fabrics, woven fabrics, and knitted fabrics of polyester fibers, polyethylene fibers, nylon fibers, acrylic fibers, polyurethane fibers, acetate fibers, rayon fibers, polylactic acid fibers, cotton, hemp, silk, wool, glass fibers, carbon fibers, and blend fibers thereof; a nonwoven fabric obtained by impregnating the nonwoven fabric with a resin such as a polyurethane resin; a nonwoven fabric having a porous layer further provided on the nonwoven fabric; and resin substrates such as thermoplastic urethane (TPU).

The polyurethane layer (ii) is formed of the foamed sheet, and the density thereof is preferably 300 to 900kg/m in order to obtain a synthetic leather having both more excellent texture and peel strength³More preferably 400 to 800kg/m³The range of (1). The density of the polyurethane layer (ii) is a value obtained by dividing a value obtained by subtracting the weight of the base material (i) per 10cm square from the weight of the synthetic leather per 10cm square by the thickness of the polyurethane layer (ii). The density of the polyurethane layer (ii) can be adjusted by foaming the urethane resin composition.

The skin-like layer (iii) may be formed by a known method using a known material, and for example, a solvent-based urethane resin, an aqueous urethane resin, a silicone resin, a polypropylene resin, a polyester resin, or the like may be used. When soft hand, heat resistance and hydrolysis resistance are important, a polycarbonate-based urethane resin is preferably used. In order to reduce DMF in environmental regulations, it is more preferable to use an aqueous polycarbonate-based urethane resin.

The surface treatment layer (iv) may be provided on the skin layer (iii) as necessary for the purpose of improving scratch resistance and the like. The surface treatment layer (iv) may be formed by a known method using a known material.

As described above, the synthetic leather of the present invention can be further excellent in peel strength and can be uniformly embossed on the surface thereof with excellent design properties by using the foamed urethane sheet excellent in touch and tensile strength.

Examples of the method for embossing the polyurethane layer (ii) include the following methods: a method in which a release paper having a design such as a concave-convex pattern is placed on the polyurethane layer (ii) of the synthetic leather and hot-pressed with a preheated roll or the like; and a method of hot pressing by using a roll coater having a design such as a concave-convex pattern. In the hot pressing, the roll may be heated at 50 to 200 ℃.

Examples

The present invention will be described in more detail below with reference to examples.

Synthesis example 1 preparation of urethane resin (A-1) composition

In the presence of 3,281 parts by mass of methyl ethyl ketone and 0.1 part by mass of stannous octoate, 1,000 parts by mass of polycarbonate polyol (1, 6-hexanediol as a raw material, number average molecular weight: 2,000), 17 parts by mass of 2, 2-dimethylolpropionic acid, 47 parts by mass of ethylene glycol, and 344 parts by mass of diphenylmethane diisocyanate were reacted at 70 ℃ until the solution viscosity reached 20,000 mPas, and then 3 parts by mass of methanol was added to stop the reaction, thereby obtaining a methyl ethyl ketone solution of a urethane resin. 70 parts by mass of polyoxyethylene distyrenated phenyl ether (hereinafter abbreviated as "HLB"); 14) and 13 parts by mass of triethylamine were mixed in this urethane resin solution, and then 800 parts by mass of ion-exchanged water was added to conduct phase inversion emulsification, thereby obtaining an emulsion in which the urethane resin (A-1) was dispersed in water.

Then, methyl ethyl ketone was distilled off from the above emulsion, thereby obtaining a urethane resin composition containing 50 mass% of urethane resin (a-1).

Synthesis example 2 preparation of urethane resin (A-2) composition

In the presence of 3,281 parts by mass of methyl ethyl ketone and 0.1 part by mass of stannous octoate, 1,000 parts by mass of polyoxytetramethylene glycol (number average molecular weight: 2,000), 17 parts by mass of 2, 2-dimethylolpropionic acid, 47 parts by mass of ethylene glycol and 344 parts by mass of MDI were reacted at 70 ℃ until the solution viscosity reached 20,000 mPas, and then 3 parts by mass of methanol was added to stop the reaction, thereby obtaining a methyl ethyl ketone solution of a urethane resin. An emulsion of the urethane resin (a-2) dispersed in water was obtained by mixing 70 parts by mass of polyoxyethylene distyrenated phenyl ether (HLB: 14) and 13 parts by mass of triethylamine in the urethane resin solution, and then adding 800 parts by mass of ion-exchanged water to the mixture to perform phase inversion emulsification.

Then, methyl ethyl ketone was distilled off from the above emulsion, thereby obtaining a urethane resin composition containing 50 mass% of the urethane resin (a-2).

[ Synthesis example 3] preparation of urethane resin (A-3) composition

A methyl ethyl ketone solution of a urethane resin was obtained by reacting 300 parts by mass of a polycarbonate polyol (1, 6-hexanediol as a raw material, number average molecular weight: 2,000), 700 parts by mass of polyoxytetramethylene glycol (number average molecular weight: 2,000), 17 parts by mass of 2, 2-dimethylolpropionic acid, 47 parts by mass of ethylene glycol, and 344 parts by mass of MDI at 70 ℃ in the presence of 3,281 parts by mass of methyl ethyl ketone and 0.1 part by mass of stannous octoate until the solution viscosity reached 20,000 mPas, and then adding 3 parts by mass of methanol to stop the reaction. An emulsion of the urethane resin (a-3) dispersed in water was obtained by mixing 70 parts by mass of polyoxyethylene distyrenated phenyl ether (HLB: 14) and 13 parts by mass of triethylamine in the urethane resin solution, and then adding 800 parts by mass of ion-exchanged water to the mixture to perform phase inversion emulsification.

Then, methyl ethyl ketone was distilled off from the above emulsion, thereby obtaining a urethane resin composition containing 50 mass% of the urethane resin (a-3).

[ Synthesis example 4] preparation of urethane resin (A-4) composition

A methyl ethyl ketone solution of a urethane resin was obtained by reacting 500 parts by mass of a polycarbonate polyol (1, 6-hexanediol as a raw material, number average molecular weight: 2,000), 500 parts by mass of polyoxytetramethylene glycol (number average molecular weight: 2,000), 17 parts by mass of 2, 2-dimethylolpropionic acid, 47 parts by mass of ethylene glycol, and 344 parts by mass of MDI at 70 ℃ in the presence of 3,281 parts by mass of methyl ethyl ketone and 0.1 part by mass of stannous octoate until the solution viscosity reached 20,000 mPas, and then adding 3 parts by mass of methanol to terminate the reaction. This urethane resin solution was mixed with 70 parts by mass of polyoxyethylene distyrenated phenyl ether (HLB: 14) and 13 parts by mass of triethylamine, and then 800 parts by mass of ion-exchanged water was added to carry out phase inversion emulsification, thereby obtaining an emulsion in which the urethane resin (a-4) was dispersed in water.

Then, methyl ethyl ketone was distilled off from the above emulsion, thereby obtaining a urethane resin composition containing 50 mass% of the urethane resin (a-4).

[ example 1]

To 30 parts by mass of the urethane resin (A-1) composition obtained in Synthesis example 1 and 70 parts by mass of the urethane resin (A-2) composition obtained in Synthesis example 2 were added 2 parts by mass of a thickener (Borchi Gel ALA manufactured by Borchers Inc.), 0.5 part by mass of ammonium stearate, and 4 parts by mass of a crosslinking agent (EPOCROS WS-700 manufactured by Japanese catalyst corporation), and the mixture was stirred at 2,000rpm for 1 minute by using a mechanical mixer to foam the mixture, thereby obtaining a foaming liquid having a volume of 1.5 times.

This was applied to a release paper, and dried at 80 ℃ for 3 minutes and further at 120 ℃ for 2 minutes, thereby producing a foamed urethane sheet.

[ example 2]

A foamed urethane sheet was obtained in the same manner as in example 1 except that the loading of the urethane resin (A-1) was changed to 50 parts by mass and the loading of the urethane resin (A-2) was changed to 50 parts by mass in addition to example 1.

[ example 3]

A foamed urethane sheet was obtained in the same manner as in example 1 except that the loading of the urethane resin (A-1) was changed to 80 parts by mass and the loading of the urethane resin (A-2) was changed to 20 parts by mass in addition to example 1.

[ example 4]

To 100 parts by mass of the urethane resin (A-3) composition obtained in Synthesis example 3 were added 2 parts by mass of a thickener ("Borchi Gel ALA" manufactured by Borchers corporation), 0.5 part by mass of ammonium stearate, and 4 parts by mass of a crosslinking agent ("EPOCROS WS-700" manufactured by Japanese catalyst corporation), and the mixture was stirred at 2,000rpm for 1 minute by using a mechanical mixer to foam the mixture, thereby obtaining a foaming solution having a volume of 1.5 times.

This was applied to a release paper, and dried at 80 ℃ for 3 minutes and further at 120 ℃ for 2 minutes, thereby producing a foamed urethane sheet.

[ example 5]

To 100 parts by mass of the urethane resin (A-4) composition obtained in Synthesis example 4 were added 2 parts by mass of a thickener ("Borchi Gel ALA" manufactured by Borchers corporation), 0.5 part by mass of ammonium stearate, and 4 parts by mass of a crosslinking agent ("EPOCROS WS-700" manufactured by Japanese catalyst corporation), and the mixture was stirred at 2,000rpm for 1 minute by using a mechanical mixer to foam the mixture, thereby obtaining a foaming solution having a volume of 1.5 times.

This was applied to a release paper, and dried at 80 ℃ for 3 minutes and further at 120 ℃ for 2 minutes, thereby producing a foamed urethane sheet.

Comparative example 1

To 30 parts by mass of the urethane resin (A-1) composition obtained in Synthesis example 1 and 70 parts by mass of the urethane resin (A-2) composition obtained in Synthesis example 2 were added 2 parts by mass of a thickener ("Borchi Gel ALA" manufactured by Borcher corporation), 1.5 parts by mass of sodium dodecylbenzenesulfonate and 4 parts by mass of a crosslinking agent ("EPOCROS WS-700" manufactured by Japanese catalyst corporation), and the mixture was stirred at 2,000rpm for 1 minute by using a mechanical mixer to foam the mixture, thereby obtaining a foaming solution having a volume of 1.5 times.

This was applied to a release paper, and dried at 80 ℃ for 3 minutes and further at 120 ℃ for 2 minutes, thereby producing a sheet.

Comparative example 2

To 100 parts by mass of the urethane resin (A-1) composition obtained in Synthesis example 1 were added 2 parts by mass of a thickener ("Borchi Gel ALA" manufactured by Borchers corporation), 0.5 part by mass of ammonium stearate, and 4 parts by mass of a crosslinking agent ("EPOCROS WS-700" manufactured by Japanese catalyst corporation), and the mixture was stirred at 2,000rpm for 1 minute by using a mechanical mixer to foam the mixture, thereby obtaining a foaming solution having a volume of 1.5 times.

This was applied to a release paper, and dried at 80 ℃ for 3 minutes and further at 120 ℃ for 2 minutes, thereby producing a foamed urethane sheet.

Comparative example 3

To 100 parts by mass of the urethane resin (A-2) composition obtained in Synthesis example 2 were added 2 parts by mass of a thickener ("Borchi Gel ALA" manufactured by Borchers corporation), 0.5 part by mass of ammonium stearate, and 4 parts by mass of a crosslinking agent ("EPOCROS WS-700" manufactured by Japanese catalyst corporation), and the mixture was stirred at 2,000rpm for 1 minute by using a mechanical mixer to foam the mixture, thereby obtaining a foaming solution having a volume of 1.5 times.

This was applied to a release paper, and dried at 80 ℃ for 3 minutes and further at 120 ℃ for 2 minutes, thereby producing a foamed urethane sheet.

[ method for measuring number average molecular weight ]

The number average molecular weight of the polyol used in the synthesis examples was measured by gel permeation column chromatography (GPC) under the following conditions.

A measuring device: high-speed GPC apparatus (HLC-8220 GPC, Tosoh corporation): the following columns manufactured by Tosoh corporation were connected in series and used.

"TSKgel G5000" (7.8 mmI.D.. times.30 cm). times.1 roots

"TSKgel G4000" (7.8mm I.D.. times.30 cm). times.1 roots

"TSKgel G3000" (7.8 mmI.D.. times.30 cm). times.1 roots

"TSKgel G2000" (7.8 mmI.D.. times.30 cm). times.1 roots

A detector: RI (differential refractometer)

Column temperature: 40 deg.C

Eluent: tetrahydrofuran (THF)

Flow rate: 1.0 mL/min

Injection amount: 100 μ L (tetrahydrofuran solution with a sample concentration of 0.4% by mass)

Standard sample: the standard curve was prepared using the standard polystyrene described below.

(Standard polystyrene)

TSKgel Standard polystyrene A-500 manufactured by Tosoh corporation "

TSKgel Standard polystyrene A-1000 manufactured by Tosoh corporation "

TSKgel Standard polystyrene A-2500 manufactured by Tosoh corporation "

TSKgel Standard polystyrene A-5000 manufactured by Tosoh corporation "

TSKgel Standard polystyrene F-1 manufactured by Tosoh corporation "

TSKgel Standard polystyrene F-2 manufactured by Tosoh corporation "

TSKgel Standard polystyrene F-4 manufactured by Tosoh corporation "

TSKgel Standard polystyrene F-10 manufactured by Tosoh corporation "

TSKgel Standard polystyrene F-20 manufactured by Tosoh corporation "

TSKgel Standard polystyrene F-40 manufactured by Tosoh corporation "

TSKgel Standard polystyrene F-80 manufactured by Tosoh corporation "

TSKgel Standard polystyrene F-128 manufactured by Tosoh corporation "

TSKgel Standard polystyrene F-288 manufactured by Tosoh corporation "

TSKgel Standard polystyrene F-550 manufactured by Tosoh corporation "

[ method for measuring flow initiation temperature of urethane resin (A) ]

The urethane resin composition obtained in the synthesis example was applied to release paper (coating thickness 150 μm), and dried at 70 ℃ for 4 minutes and then at 120 ℃ for 2 minutes by a hot air dryer, thereby obtaining a dried product. The dried product was measured for its flow initiation temperature using a flow tester "CFT-500A" (using a mold having a diameter of 1mm and a length of 1mm, a load of 98N and a temperature rise rate of 3 ℃/min, manufactured by Shimadzu corporation).

[ method of evaluating hand feeling ]

The resulting foamed urethane sheet was touched with a hand and evaluated as follows.

"A": has high flexibility.

"B": has slight flexibility.

"C": the flexibility was poor.

"D": hard.

[ method for resisting oil and acid ]

The foamed urethane sheets obtained in examples and comparative examples were bonded to a nonwoven fabric to obtain a synthetic leather. The obtained synthetic leather was cut into a width of 50mm and a length of 50mm, and the cut pieces were used as test pieces. The test piece was immersed in oleic acid at 80 ℃ for 24 hours and then taken out, and the oleic acid adhering to the surface was gently wiped off with a paper towel. The appearance change before and after the impregnation with oleic acid was visually observed and evaluated as follows.

"T": no appearance change.

"F": the synthetic leather expands and/or deforms.

[ method of Low temperature bendability ]

The foamed urethane sheets obtained in examples and comparative examples were bonded to a nonwoven fabric to obtain a synthetic leather. The obtained synthetic leather was subjected to a bending test (30 ℃ C., 100 times/min) using a flexibility meter (a "low-temperature flexibility meter" manufactured by Anta Seisakusho K.K.) and the number of times until abrasion was generated on the surface of the synthetic leather was measured, and evaluated as follows.

"A": more than 15,000 times

"B": more than 10,000 times and less than 15,000 times

"C": less than 10,000 times

[ Table 1]

[ Table 2]

It is understood that the urethane resin composition of the present invention has excellent hand, resistance to oil acidity and low-temperature bending.

On the other hand, in comparative example 1, in which sodium dodecylbenzenesulfonate having an aromatic ring was used in place of the surfactant (C), the foam retention was poor, and the hand was hard and poor.

Comparative example 2 is an embodiment using a urethane resin composition containing no oxyalkylene structure (Y), and the low-temperature flexibility is poor.

Comparative example 3 is an embodiment using a urethane resin composition containing no carbonate structure (X), and is resistant to poor oil acidity.