JP6650124B2 - Urethane resin composition and leather-like sheet - Google Patents

Description

  The present invention particularly relates to a urethane resin composition that can be suitably used for producing a top coat layer, a skin layer, and an intermediate layer of a leather-like sheet such as synthetic leather and artificial leather.

  BACKGROUND ART In a process of producing a leather-like sheet such as synthetic leather or artificial leather, a porous film using a urethane resin composition is used for the purpose of improving the texture of synthetic leather. As the urethane resin composition, for example, a urethane resin composition containing a urethane resin by reacting polyisocyanate with a polyester polyol using ethylene glycol and 1,4-butanediol as a glycol component is disclosed (for example, And Patent Document 1.).

  However, a porous film made of a polyester polyol-based urethane resin has a problem that the texture tends to be hard and the hydrolysis resistance is poor.

JP 2013-23691 A

  The problem to be solved by the present invention is to provide a urethane resin composition capable of maintaining a soft texture and hydrolysis resistance while maintaining film formability and heat resistance.

  In the present invention, the aliphatic polyester polyol (a-1-1) and the polyether polyol (a-1-2) are (a-1-1) / (a-1-2) = 80/20 by mass ratio. A urethane resin (A) obtained by reacting a polyol (a-1), a chain extender (a-2), and a polyisocyanate (a-3) contained in a range of from 50 to 50/50, and an organic solvent ( It is intended to provide a urethane resin composition characterized by containing B) and a urethane resin composition characterized by containing an organic solvent (B).

  The present invention also provides a leather-like sheet obtained by forming a film of the urethane resin composition.

  The urethane resin composition of the present invention can provide a film having excellent film-forming properties, heat resistance, soft texture, and hydrolysis resistance. Therefore, the urethane resin composition of the present invention can be used as a polishing pad for a top coat layer, a skin layer, an intermediate layer of a leather-like sheet such as a synthetic leather or an artificial leather used for clothing, vehicle seats, furniture sheets, shoes, bags and the like. Backing pads for polishing; medical hygiene materials such as surgical gowns and bed sheets; sheets for building materials such as windproof / waterproof sheets and condensation prevention sheets; packaging materials such as desiccants, dehumidifiers, and aromatics; agricultural sheets and various separators It can be used for various applications such as an intermediate layer and a skin layer constituting a packing or the like.

  Above all, the urethane resin composition of the present invention can be suitably used for producing a top coat layer, a skin layer, and an intermediate layer of a leather-like sheet such as synthetic leather and artificial leather.

  The urethane resin composition of the present invention comprises the aliphatic polyester polyol (a-1-1) and the polyether polyol (a-1-2) in a mass ratio of (a-1-1) / (a-1-2). A) a urethane resin (A) obtained by reacting a polyol (a-1), a chain extender (a-2) and a polyisocyanate (a-3) contained in the range of 80/20 to 50/50; And an organic solvent (B).

  As the aliphatic polyester polyol, for example, those obtained by a known esterification reaction of a compound having two or more hydroxyl groups and a polybasic acid can be used.

  Examples of the compound having two or more hydroxyl groups include ethylene glycol, propylene glycol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, diethylene glycol, and triethylene glycol. Glycol compounds such as ethylene glycol, tetraethylene glycol, dipropylene glycol, tripropylene glycol, 1,4-cyclohexanediol and 1,4-cyclohexanedimethanol; 2-methyl-1,5-pentanediol, 3-methyl-1 , 5-pentanediol, 1,2-butanediol, 1,3-butanediol, 2-butyl-2-ethyl-1,3-propanediol, 1,2-propanediol, 2-methyl-1,3- Propanediol, neopentyl glycol, -Isopropyl-1,4-butanediol, 2,4-dimethyl-1,5-pentanediol 2,4-diethyl-1,5-pentanediol, 2-ethyl-1,3-hexanediol, 2-ethyl- Glycol compounds having a branched structure such as 1,6-hexanediol, 3,5-heptanediol, 2-methyl-1,8-octanediol; trimethylolpropane, trimethylolethane, pentaerythritol, sorbitol and the like can be used. it can. These compounds may be used alone or in combination of two or more.

  Examples of the polybasic acid include succinic acid, adipic acid, azelaic acid, sebacic acid, dodecanedicarboxylic acid, maleic anhydride, fumaric acid, 1,3-cyclopentanedicarboxylic acid, 1,4-cyclohexanedicarboxylic acid, and the like. Acid anhydrides and the like can be used. These polybasic acids may be used alone or in combination of two or more.

  As the aliphatic polyester polyol (a-1-1), from the viewpoint of improving the hydrophilicity of the urethane resin (A) by disturbing the crystal structure and further improving the film forming property (particularly, wet film forming property), It is preferable to use an aliphatic polyester polyol obtained by reacting a glycol compound containing a glycol compound having a branched structure with adipic acid, and neopentyl glycol, 3-methyl-1,5-pentanediol, or 2-methyl -1,3-propanediol, ethylene glycol, 1,3-propanediol, 1,4-butanediol, or 1,6-hexanediol, and an aliphatic polyester polyol obtained by reacting adipic acid; More preferably, neopentyl glycol or 3-methyl-1,5-pentanedioate is used. When the 1,3-propanediol or 1,4-butanediol, it is more preferable to use an aliphatic polyester polyol obtained by reacting adipic acid. Also, the neopentyl glycol, 3-methyl-1,5-pentanediol, or 2-methyl-1,3-propanediol, and the ethylene glycol, 1,3-propanediol, 1,4-butanediol, Alternatively, the charged molar ratio with 1,6-hexanediol is preferably in the range of 30/70 to 70/30, and more preferably in the range of 60/40 to 40/60.

  The number average molecular weight of the aliphatic polyester polyol (a-1-1) is preferably in the range of 500 to 8,000 from the viewpoint of hydrolyzability and wet film formability, and is preferably in the range of 600 to 5,000. More preferably, it is in the range of 800 to 3,000. In addition, the number average molecular weight of the aliphatic polyester polyol (a-1-1) indicates a value measured by gel permeation chromatography (GPC) under the following conditions.

Measuring device: High-speed GPC device (“HLC-8220GPC” manufactured by Tosoh Corporation)
Column: The following columns manufactured by Tosoh Corporation were connected in series and used.
"TSKgel G5000" (7.8 mm ID x 30 cm) x 1 "TSKgel G4000" (7.8 mm ID x 30 cm) x 1 "TSKgel G3000" (7.8 mm ID x 30 cm) x 1 Book “TSKgel G2000” (7.8 mm ID × 30 cm) × 1 Detector: RI (differential refractometer)
Column temperature: 40 ° C
Eluent: tetrahydrofuran (THF)
Flow rate: 1.0 mL / min Injection volume: 100 μL (sample concentration: 0.4% by mass in tetrahydrofuran solution)
Standard sample: A calibration curve was prepared using the following standard polystyrene.

(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

  Examples of the polyether polyol (a-1-2) include polyoxyethylene glycol, polyoxypropylene glycol, polyoxytetramethylene glycol, polyoxyethylene polyoxypropylene glycol, polyoxyethylene polyoxytetramethylene glycol, and polyoxyethylene glycol. Oxypropylene polyoxytetramethylene glycol or the like can be used. These polyether polyols may be used alone or in combination of two or more. Among these, it is preferable to use polyoxytetramethylene glycol from the viewpoint that a higher texture can be obtained by reducing the crystal structure of the polymer.

  The number average molecular weight of the polyether polyol (a-1-2) is preferably in the range of 500 to 5,000, and more preferably in the range of 700 to 3,000, from the viewpoint of heat resistance and wet film forming properties. More preferably, there is. The number average molecular weight of the polyether polyol (a-1-2) indicates a value obtained by measuring the same as the number average molecular weight of the aliphatic polyester polyol (a-1-1).

  The mass ratio [(a-1-1) / (a-1-2)] between the aliphatic polyester polyol (a-1-1) and the polyether polyol (a-1-2) is defined as film formation. It is essential that the ratio be in the range of 80/20 to 50/50 in order to achieve both soft texture and hydrolysis resistance while maintaining the heat resistance and heat resistance. When the mass ratio of the aliphatic polyester polyol (a-1-1) exceeds the above range, the amount of ester groups in the polymer increases, so that the hydrolysis resistance becomes poor, and when the mass ratio is below the above range, In the case of (1), the film itself is poor because the polymer itself has high hydrophobicity. The mass ratio is preferably in the range of 65/35 to 55/45 from the viewpoint that by controlling the hydrophilicity / hydrophobicity of the polymer, a higher wet film formability and a better texture can be obtained. preferable.

  The polyol (a-1) contains the aliphatic polyester polyol (a-1-1) and the polyether polyol (a-1-2), but may contain other polyols as necessary. Good. As the other polyol, for example, polycarbonate polyol, polyacryl polyol, polybutadiene polyol, dimer diol and the like can be used. These polyols may be used alone or in combination of two or more. When the other polyol is used, the amount used is preferably 20% by mass or less, more preferably 10% by mass or less in the polyol (a-1).

  As the chain extender (a-2), for example, a chain extender having a hydroxyl group, a chain extender having an amino group and the like can be used. These chain extenders may be used alone or in combination of two or more.

  Examples of the chain extender having a hydroxyl group include, for example, ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, 1,3-propanediol, 1,3-butanediol, 1,4-butanediol, hexamethylene glycol, Aliphatic polyol compounds such as saccharose, methylene glycol, glycerin, sorbitol; bisphenol A, 4,4'-dihydroxydiphenyl, 4,4'-dihydroxydiphenyl ether, 4,4'-dihydroxydiphenylsulfone, hydrogenated bisphenol A, hydroquinone, etc. Aromatic polyol compound; water and the like. These chain extenders may be used alone or in combination of two or more.

  Examples of the chain extender having an amino group include ethylenediamine, 1,2-propanediamine, 1,6-hexamethylenediamine, piperazine, 2-methylpiperazine, 2,5-dimethylpiperazine, isophoronediamine, and 4,4. '-Dicyclohexylmethanediamine, 3,3'-dimethyl-4,4'-dicyclohexylmethanediamine, 1,2-cyclohexanediamine, 1,4-cyclohexanediamine, aminoethylethanolamine, hydrazine, diethylenetriamine, triethylenetetramine, etc. Can be used. These chain extenders may be used alone or in combination of two or more.

  As the chain extender (a-2), a chain extender having a hydroxyl group can be used because it can suppress the successive discoloration of the leather-like sheet and can further improve heat resistance, cold bending resistance and texture. It is preferable to use 1,4-butanediol and / or ethylene glycol, and it is more preferable to use 1,4-butanediol or ethylene glycol.

  The amount of the chain extender (a-2) to be used is 0.5 to 30 with respect to 100 parts by mass of the polyol (a-1) from the viewpoint of further improving heat resistance, cold bending resistance and texture. It is preferably in the range of parts by mass, more preferably in the range of 5 to 20 parts by mass.

  Examples of the polyisocyanate (a-3) include 1,3-phenylene diisocyanate, 1,4-phenylene diisocyanate, 1-methyl-2,4-phenylene diisocyanate, 1-methyl-2,6-phenylene diisocyanate, -Methyl-2,5-phenylene diisocyanate, 1-methyl-2,6-phenylene diisocyanate, 1-methyl-3,5-phenylene diisocyanate, 1-ethyl-2,4-phenylene diisocyanate, 1-isopropyl-2,4 -Phenylene diisocyanate, 1,3-dimethyl-2,4-phenylene diisocyanate, 1,3-dimethyl-4,6-phenylene diisocyanate, 1,4-dimethyl-2,5-phenylene diisocyanate, diethylbenzene diisocyanate, diisobenzene Propylbenzene diisocyanate, 1-methyl-3,5-diethylbenzene diisocyanate, 3-methyl-1,5-diethylbenzene-2,4-diisocyanate, 1,3,5-triethylbenzene-2,4-diisocyanate, naphthalene-1 , 4-Diisocyanate, naphthalene-1,5-diisocyanate, 1-methyl-naphthalene-1,5-diisocyanate, naphthalene-2,6-diisocyanate, naphthalene-2,7-diisocyanate, 1,1-dinaphthyl-2,2 '-Diisocyanate, biphenyl-2,4'-diisocyanate, biphenyl-4,4'-diisocyanate, 3-3'-dimethylbiphenyl-4,4'-diisocyanate, 4,4'-diphenylmethane diisocyanate, 2,2'- Diphenyl meta Aromatic polyisocyanates such as diisocyanate and diphenylmethane-2,4-diisocyanate; tetramethylene diisocyanate, 1,6-hexamethylene diisocyanate, dodecamethylene diisocyanate, trimethylhexamethylene diisocyanate, 1,3-cyclopentylene diisocyanate, 1,3- Cyclohexylene diisocyanate, 1,4-cyclohexylene diisocyanate, 1,3-di (isocyanatomethyl) cyclohexane, 1,4-di (isocyanatomethyl) cyclohexane, lysine diisocyanate, isophorone diisocyanate, 4,4′-dicyclohexylmethane diisocyanate, 4,4'-dicyclohexylmethane diisocyanate, 2,2'-dicyclohexylmethane diisocyanate, 3 And aliphatic or alicyclic polyisocyanates such as 3,3'-dimethyl-4,4'-dicyclohexylmethane diisocyanate. These polyisocyanates may be used alone or in combination of two or more. Among these, it is preferable to use aromatic polyisocyanate, and it is more preferable to use 4,4'-diphenylmethane diisocyanate, since heat resistance, flexibility and texture can be further improved.

  As a method for producing the urethane resin (A), a known urethane reaction can be used. For example, after the polyol (a-1) and the chain extender (a-2) are charged and stirred, For example, a method in which the polyisocyanate (a-3) is added and reacted with the throat at 50 to 100 ° C. for 3 to 10 hours is exemplified. At this time, the molar ratio [NCO / OH] of the hydroxyl group (derived from the polyol (a-1) and the chain extender (a-3)) to the isocyanate group is in the range of 0.8 to 1.2. And more preferably in the range of 0.9 to 1.1. After the production of the urethane resin, an alcohol such as ethanol, methanol or butanol may be added for the purpose of deactivating remaining isocyanate groups.

  The weight average molecular weight of the urethane resin (A) obtained by the above method is preferably in the range of 5,000 to 500,000 from the viewpoint of further improving heat resistance, film formability, and texture. , And more preferably in the range of 10,000 to 300,000. In addition, the weight average molecular weight of the urethane resin (A) indicates a value measured in the same manner as the number average molecular weight of the aliphatic polyester polyol (a-1-1).

  Examples of the organic solvent (B) include ketones such as N, N-dimethylformamide, N, N-dimethylacetamide, N-methyl-2-pyrrolidone, methyl ethyl ketone, methyl-n-propyl ketone, acetone and methyl isobutyl ketone. Solvents: ester solvents such as methyl formate, ethyl formate, propyl formate, methyl acetate, ethyl acetate, isopropyl acetate, isobutyl acetate, isobutyl acetate, and sec-butyl acetate; use of alcohol solvents such as methanol, ethanol, isopropyl alcohol, and butanol Can be. These organic solvents may be used alone or in combination of two or more.

  Among these, N, N-dimethylformamide is preferably used because it has high solubility in the urethane resin (A) and is easily removed by drying with hot air. When the N, N-dimethylformamide is used, the content is preferably 70% by mass or more, more preferably 90% by mass or more in the organic solvent (B).

  The content of the organic solvent (B) is preferably in the range of 30 to 90% by mass in the urethane resin composition, and is preferably 40 to 80% by mass in view of workability and viscosity in handling the urethane resin composition. The range is more preferred.

  The urethane resin composition of the present invention contains the urethane resin (A) and the organic solvent (B) as essential components, but may contain other additives as necessary.

  Examples of the other additives include surfactants, pigments, catalysts, flame retardants, plasticizers, softeners, stabilizers, waxes, defoamers, dispersants, penetrants, fillers, fungicides, and antibacterial agents , An ultraviolet absorber, an antioxidant, a weather stabilizer, a fluorescent brightener, an antioxidant, a thickener, and the like. These additives may be used alone or in combination of two or more.

  Next, a method for producing a leather-like sheet by forming a film of the urethane resin composition of the present invention will be described.

  Examples of the method for forming a film of the urethane resin composition include a method of forming a film by a dry film forming method, a wet film forming method, or the like.

  The dry film formation is a method of applying the urethane resin composition on release paper and drying the organic solvent (B).

  Examples of a method for applying the urethane resin composition on the release paper include a gravure coater method, a knife coater method, a pipe coater method, and a comma coater method.

  The drying after the application is performed, for example, for 1 to 60 minutes using a dryer adjusted to 80 to 120 ° C.

  The thickness of the urethane resin composition after drying is appropriately determined according to the intended use, and is, for example, in the range of 0.001 to 10 mm.

  As a method for producing a leather-like sheet using the dry film obtained by the dry film forming method, for example, the film is preferably formed by using a known adhesive, a known base cloth, an intermediate layer, and a skin. By adhering on a layer or the like, a leather-like sheet can be produced.

  As the base cloth, for example, a substrate made of a nonwoven fabric, a woven fabric, or a knit can be used. Examples of the base fabric include chemical fibers such as polyester fiber, nylon fiber, acrylic fiber, polyurethane fiber, acetate fiber, rayon fiber, and polylactic acid fiber; cotton, hemp, silk, wool, and blended fibers thereof. Etc. can be used.

  The wet film forming method is to coat or impregnate the urethane resin composition on the surface of the base fabric or the resin film, and then contact the coated surface or the impregnated surface with water or water vapor to form the urethane resin. This is a method for producing a porous body by coagulating (A).

  On the surface of the base fabric or the resin film, antistatic processing, release processing, water repellent processing, water absorbing processing, antibacterial deodorant processing, antibacterial processing, ultraviolet ray blocking processing, etc. are applied as necessary. Is also good.

  Examples of a method of applying or impregnating the urethane resin composition on the surface of the base fabric or the resin film include a gravure coater method, a knife coater method, a pipe coater method, and a comma coater method. At that time, in order to adjust the viscosity of the urethane resin composition and improve the coating workability, the amount of the organic solvent (B) used may be further adjusted as necessary.

  The thickness of the coating film composed of the urethane resin composition applied or impregnated by the above method is appropriately determined according to the intended use, and is, for example, in the range of 0.001 to 10 mm.

  As a method of bringing water or water vapor into contact with the coated surface formed by applying or impregnating the urethane resin composition, for example, a base cloth provided with an application layer or an impregnation layer formed of the urethane resin composition is placed in a water bath. A method of immersing; a method of spraying water on the coated surface using a spray or the like. The immersion can be performed, for example, in a water bath at 5 to 60 ° C. for 2 to 20 minutes.

  It is preferable that the surface of the porous body obtained by the above method is washed with water at normal temperature or warm water to extract and remove the organic solvent (X), and then dried. The washing is preferably performed with water at 5 to 60 ° C. for 20 to 120 minutes, and the water used for washing is preferably replaced at least once or continuously with running water. The drying is preferably performed for 10 to 60 minutes using a dryer or the like adjusted to 80 to 120 ° C.

  When the object to be coated is the base cloth, a wet layer comprising a film of the urethane resin composition is formed on the base cloth layer by the above method, and the wet layer is preferably formed using a known adhesive. A leather-like sheet can be manufactured by forming a known intermediate layer and a skin layer thereon and further forming a top coat layer as needed.

  When the object to be coated is the resin film, the obtained porous body is preferably adhered to a known base cloth, an intermediate layer, a skin layer, or the like using a known adhesive layer. Thereby, a leather-like sheet can be manufactured.

  The urethane resin composition of the present invention can provide a film having excellent film-forming properties, heat resistance, soft texture, and hydrolysis resistance. Accordingly, the urethane resin composition of the present invention can be used as a polishing pad for a leather-like sheet such as synthetic leather or artificial leather used for clothing, vehicle seats, furniture sheets, shoes, bags, and the like; Backing pads for polishing; medical hygiene materials such as surgical gowns and bed sheets; sheets for construction materials such as windproof / waterproof sheets and dew condensation prevention sheets; packaging materials such as desiccants, dehumidifiers, and fragrances; agricultural sheets and various separators It can be used for various applications such as an intermediate layer and a skin layer constituting a packing or the like.

  Above all, the urethane resin composition of the present invention can be suitably used for producing a top coat layer, a skin layer, and an intermediate layer of a leather-like sheet such as synthetic leather and artificial leather.

  Hereinafter, the present invention will be described in more detail with reference to Examples.

[Example 1]
PEs-1 (neopentyl glycol (NPG), diethylene glycol (DEG), and adipic acid (AA) reacted in a reactor having a stirrer, reflux tube, and thermometer, NPG: DEG (molar ratio) = 70 30, number average molecular weight; 2,000) 75 parts by mass, polyoxytetramethylene glycol (number average molecular weight; 1,000, hereinafter referred to as “PTMG1000”) 25 parts by mass, ethylene glycol (hereinafter abbreviated as “EG”). After adding 18 parts by mass and stirring, 650 parts by mass of N, N-dimethylformamide (hereinafter abbreviated as "DMF") are added and stirred, and then 4,4'-diphenylmethane diisocyanate (hereinafter abbreviated as "MDI"). 160 parts by mass, and reacted at 80 ° C. for 3 hours, urethane containing urethane resin having a weight average molecular weight of 100,00 A resin composition was obtained.

[Example 2]
60 parts by mass of PEs-2 (reacted with neopentyl glycol (NPG) and adipic acid (AA), number average molecular weight: 2,000) in a reactor having a stirrer, a reflux tube, and a thermometer, and 60 parts by mass of PTMG1000. After adding 40 parts by mass and 15 parts by mass of 1,4-butanediol (hereinafter abbreviated as "BG"), stirring, 320 parts by mass of DMF and stirring, and adding 22.5 parts by mass of MDI, add 80 parts by mass. C. for 3 hours to obtain a urethane resin composition containing a urethane resin having a weight average molecular weight of 110,000.

[Example 3]
A reactor having a stirrer, a reflux tube, and a thermometer was reacted with PEs-3 (ethylene glycol (EG) and adipic acid (AA), number average molecular weight: 2,500), 60 parts by mass, and PTMG1000 at 40 parts by mass. After adding 455 parts by mass of DMF and stirring, 82.5 parts by mass of MDI was added, and the mixture was reacted at 80 ° C. for 3 hours to obtain a mixture having a weight average molecular weight of 105,000. A urethane resin composition containing a urethane resin was obtained.

[Example 4]
PEs-4 (ethylene glycol (EG), 1,4-butanediol (BG), and sebacic acid (SEBA) reacted with a reactor having a stirrer, a reflux tube, and a thermometer; EG: BG (mol Ratio) = 60: 40, number average molecular weight; 2,000) 65 parts by mass, 35 parts by mass of polyoxytetramethylene glycol (number average molecular weight; 1,300, hereinafter “PTMG1300”), and 15 parts by mass of BG, After stirring, 380 parts by mass of DMF was added and stirred. Then, 47.5 parts by mass of MDI was added and reacted at 80 ° C. for 3 hours to obtain a urethane resin composition containing a urethane resin having a weight average molecular weight of 120,000. Was.

[Example 5]
PEs-5 (1,4-butanediol (BG), 1,6-hexanediol (HG), and adipic acid (AA) reacted with a reactor having a stirrer, a reflux tube, and a thermometer, EG : HG (molar ratio) = 50:50, number average molecular weight; 2,300) 60 parts by mass, 40 parts by mass of PTMG1300, 13 parts by mass of EG, and after stirring, 425 parts by mass of DMF were added and stirred. 67.5 parts by mass of MDI was added and reacted at 80 ° C. for 3 hours to obtain a urethane resin composition containing a urethane resin having a weight average molecular weight of 115,000.

[Example 6]
Reaction of PEs-6 (1,3-propanediol (PG), neopentyl glycol (NPG) and adipic acid (AA) in a reactor having a stirrer, a reflux tube, and a thermometer, PG: NPG ( (Molar ratio) = 50: 50, number average molecular weight; 2,300) 55 parts by mass, 45 parts by mass of PTMG1000, 18 parts by mass of EG, stirring, 420 parts by mass of DMF, stirring, and MDI of 62 parts. The mixture was reacted at 80 ° C. for 3 hours to obtain a urethane resin composition containing a urethane resin having a weight average molecular weight of 100,000.

[Example 7]
60 parts by mass of PEs-7 (1,4-butanediol (BG) and adipic acid (AA) reacted in a reactor having a stirrer, reflux tube, and thermometer, number average molecular weight: 2,500) , PTMG1300 (40 parts by mass), BG (15 parts by mass), stirring, DMF (305 parts by mass), stirring, MDI (15.5 parts by mass), reaction at 80 ° C. for 3 hours, weight average molecular weight; A urethane resin composition containing 115,000 urethane resins was obtained.

Example 8
PEs-8 (ethylene glycol (EG), 3-methylpentanediol (3MPG) and sebacic acid (SEBA) reacted with a reactor having a stirrer, a reflux tube, and a thermometer, EG: 3MPG (molar ratio) ) = 60: 40, number average molecular weight: 2,300) 55 parts by mass, 45 parts by mass of PTMG1300, 13 parts by mass of EG, stirring, 435 parts by mass of DMF, stirring, and 72.5 parts of MDI The reaction was carried out at 80 ° C. for 3 hours to obtain a urethane resin composition containing a urethane resin having a weight average molecular weight of 120,000.

[Comparative Example 1]
PEs-9 (ethylene glycol (EG), 1,4-butanediol (BG) and adipic acid (AA) reacted with a reactor having a stirrer, a reflux tube, and a thermometer, EG: BG (mol Ratio) = 60: 40, number average molecular weight: 2,000) 90 parts by mass, 10 parts by mass of PTMG1300, 15 parts by mass of EG, stirring, 640 parts by mass of DMF, stirring and 160 parts by mass of MDI The mixture was reacted at 80 ° C. for 3 hours to obtain a urethane resin composition containing a urethane resin having a weight average molecular weight of 90,000.

[Comparative Example 2]
PEs-10 (neopentyl glycol (NPG), diethylene glycol (DEG) and adipic acid (AA) reacted in a reactor having a stirrer, reflux tube and thermometer, NPG: DEG (molar ratio) = 50 : 50, number average molecular weight; 2,500) 85 parts by mass, 15 parts by mass of PTMG1300, 25 parts by mass of EG, and after stirring, 450 parts by mass of DMF and stirring, then 67.5 parts by mass of MDI. In addition, the mixture was reacted at 80 ° C. for 3 hours to obtain a urethane resin composition containing a urethane resin having a weight average molecular weight of 110,000.

[Comparative Example 3]
PEs-11 (neopentyl glycol (NPG), diethylene glycol (DEG), and sebacic acid (SEBA) reacted in a reactor having a stirrer, reflux tube, and thermometer, NPG: DEG (molar ratio) = 70 : 30, number average molecular weight; 2,300) 30 parts by mass, 70 parts by mass of PTMG1000, 18 parts by mass of BG, stirring, 330 parts by mass of DMF, stirring, and 23.5 parts by mass of MDI. In addition, the mixture was reacted at 80 ° C. for 3 hours to obtain a urethane resin composition containing a urethane resin having a weight average molecular weight of 110,000.

[Comparative Example 4]
10 parts by mass of PEs-12 (1,4-butanediol (BG) and adipic acid (AA) reacted in a reactor having a stirrer, reflux tube, and thermometer, number average molecular weight: 2,500) , 90 parts by weight of PTMG1300 and 18 parts by weight of EG, and after stirring, 470 parts by weight of DMF and stirring, 82.5 parts by weight of MDI were added, and the mixture was reacted at 80 ° C. for 3 hours to obtain a weight average molecular weight; A urethane resin composition containing 100,000 urethane resins was obtained.

[Comparative Example 5]
PEs-13 (ethylene glycol (EG), 1,4-butanediol (BG) and sebacic acid (SEBA) reacted in a reactor having a stirrer, a reflux tube, and a thermometer, EG: BG (mol Ratio) = 50: 50, number average molecular weight; 2,300) 40 parts by mass, 60 parts by mass of PTMG1000, 13 parts by mass of EG, stirring, 433 parts by mass of DMF, stirring, and then MDI of 72. 5 parts by mass were added and reacted at 80 ° C. for 3 hours to obtain a urethane resin composition containing a urethane resin having a weight average molecular weight of 110,000.

[Production of dry film]
The urethane resin compositions obtained in the examples and comparative examples were applied on a PET (polyethylene terephthalate) film using an applicator so that the thickness of the film after drying was 1 mm, and the temperature was 120 ° C. For 2 minutes to obtain a dry film.

[Preparation of wet film]
To 100 parts by mass of the urethane resin composition obtained in Examples and Comparative Examples, 1 part by mass of a surfactant for wet processing “Assister SD-7” manufactured by DIC Corporation was added to obtain a blended liquid, and a PET film was obtained. The coating was dried so that the thickness of the film after drying was 1 mm, and then immersed in water at 25 ° C. for 10 minutes to solidify. Thereafter, the film was washed in warm water at 50 ° C. for 60 minutes and left in a dryer at 100 ° C. for 30 minutes to obtain a porous wet film.

[Evaluation method of heat resistance]
The thermal softening point of the dry film was measured using a thermal analysis system “TAS100” manufactured by Rigaku Corporation, and evaluated as follows.
"T": thermal softening point is 200 ° C or higher.
"F": Thermal softening point is less than 200 ° C.

[Method of evaluating hydrolysis resistance]
The dry film was cured for 2 weeks at 70 ° C. and 95% humidity. The tensile strength and elongation of the dry film were measured before and after curing according to JISK-1996. The relative value after curing was calculated assuming that the value before curing was 100, and evaluated as follows.
"T"; tensile strength and elongation are in the range of 80 to 120.
"F"; either tensile strength or elongation is less than 80 or more than 120.

[Evaluation method of film forming property]
The cross section of the wet film was observed using a scanning electron microscope “SU3500” (magnification: 100 ×) manufactured by Hitachi High-Technologies Corporation, and evaluated as follows.
"T"; no collapse of the porous material was observed.
"F": Collapse of the porous material is confirmed.

[Handle evaluation method]
The wet coating was evaluated by finger touch as follows.
"T"; flexible "F"; hard

  It has been found that the urethane resin composition of the present invention can provide a film having excellent heat resistance, hydrolysis resistance, film formability and texture.

  On the other hand, Comparative Examples 1 and 2 are embodiments in which the amount of the aliphatic polyester polyol (a-1-1) used exceeds the range specified in the present invention, but both had poor hydrolysis resistance and texture. .

  Comparative Examples 3 to 5 are embodiments in which the amount of the aliphatic polyester polyol (a-1-1) used is smaller than the range specified in the present invention, but all of them had poor heat resistance and poor film formability. .

Claims (2)

The weight ratio of the aliphatic polyester polyol (a-1-1) and the polyether polyol (a-1-2) is (a-1-1) / (a-1-2) = 80/20 to 50/50. The urethane resin (A) obtained by reacting the polyol (a-1), the chain extender (a-2), and the polyisocyanate (a-3) contained in the range described above, and the organic solvent (B) A leather sheet obtained by wet film-forming a urethane resin composition containing,
The aliphatic polyester polyol (a-1-1) is composed of neopentyl glycol, 3-methyl-1,5-pentanediol, or 2-methyl-1,3-propanediol, and ethylene glycol, 1,3- A reaction product of propanediol, 1,4-butanediol, or 1,6-hexanediol with adipic acid,
The polyether polyol (a-1-2) is a polyoxytetramethylene glycol,
The polyisocyanate (a-3) is a 4,4'-diphenyl methane diisocyanate,
A leather sheet, wherein the organic solvent (B) is N, N-dimethylformamide . The leather-like sheet according to claim 1, wherein the chain extender (a-2) is 1,4-butanediol or ethylene glycol.