Moisture-curable polyurethane hot-melt resin composition, cured product, laminate, and skin material

Abstract

The present invention provides a moisture-curable hot-melt polyurethane resin composition characterized by containing a urethane prepolymer (i) having an isocyanate group, which is a reaction product of a polyol (A) and a polyisocyanate (B), the polyol (A) contains: an aromatic polyester polyol (a1) which comprises, as a starting material, a compound (x) having a molecular weight of less than 500, a branched structure, and 2-4 hydroxyl groups per molecule; an aromatic polyester polyol (a2) other than (a1); an aliphatic polyester polyol (a3); a crystalline polyester polyol (a4) other than (a3); and a polyether polyol (a5). Furthermore, the present invention provides a cured product which is characterized by being formed from the moisture-curable hot-melt polyurethane resin composition.

Description

Technical Field

[0001] The present invention relates to a moisture-curable polyurethane hot-melt resin composition, a cured product, a laminate, and a skin material. Background Art

[0002] Laminate sheets such as synthetic leather and artificial leather are used for the skin surfaces of furniture and vehicle sheets. In order to exhibit shock-absorbing properties, a buffer layer such as urethane foam (PUF) is usually provided (for example, refer to Patent Document 1). Conventionally, in the bonding of synthetic leather and PUF / PUF and a mesh fabric (Japanese: メッシュ生地) that gives slipperiness during sewing, PUF is flame-melted by flame lamination (Japanese: フレームラミネート) (flame welding) and bonded to the skin surface / back substrate such as synthetic leather.

[0003] However, in the bonding based on the above-described flame lamination method, since a flame is used, hydrogen cyanide (HCN) is generated during manufacturing, and deterioration of the working environment becomes a problem. As an alternative, an aqueous adhesive or a solvent-based adhesive is used. However, since a drying process is required, there is a concern about a reduction in production efficiency, and it is considered that when drying is insufficient, the adhesive oozes out to the surface of the back base fabric (penetration of the adhesive), and adhesion occurs during winding.

[0004] Prior Art Documents

[0005] Patent Documents

[0006] Patent Document 1: Japanese Unexamined Patent Application Publication No. 2017-136735 Summary of the Invention

[0007] Problems to be Solved by the Invention

[0008] The problem to be solved by the present invention is to provide a moisture-curable polyurethane hot-melt resin composition having excellent initial strength, mechanical strength, and adhesiveness and capable of suppressing penetration.

[0009] Means for Solving the Problems

[0010] The present invention provides the following moisture-curable polyurethane hot-melt resin composition, which is characterized by containing a urethane prepolymer (i) having an isocyanate group, which is a reaction product of a polyol (A) and a polyisocyanate (B), wherein the polyol (A) contains: an aromatic polyester polyol (a1) made from a compound (x) having a molecular weight of less than 500, a branched structure, and 2 to 4 hydroxyl groups in one molecule; an aromatic polyester polyol (a2) other than the above (a1); an aliphatic polyester polyol (a3); a crystalline polyester polyol (a4) other than the above (a3); and a polyether polyol (a5).

[0011] The present invention also provides a cured product characterized in that it is formed from the moisture-curable polyurethane hot-melt resin composition. The present invention also provides a laminate and a skin material characterized in that it comprises a polyurethane foam, a layer formed from the cured product, and a base fabric.

[0012] Effects of the Invention

[0013] The moisture-curable polyurethane hot-melt resin composition of the present invention has excellent initial strength, mechanical strength and adhesion, and can suppress penetration. In addition, by using the moisture-curable polyurethane hot-melt resin composition, the flame melting lamination performed in the past is not required, which can also contribute to the improvement of the working environment. DETAILED DESCRIPTION

[0014] The moisture-curable polyurethane hot-melt resin composition of the present invention contains a urethane prepolymer (i) having an isocyanate group which is a reaction product of a polyol (A) and a polyisocyanate (B), wherein the polyol (A) contains: an aromatic polyester polyol (a1) made from a compound (x) having a molecular weight of less than 500, a branched structure, and 2 to 4 hydroxyl groups in one molecule; an aromatic polyester polyol (a2) other than the above (a1); an aliphatic polyester polyol (a3); a crystalline polyester polyol (a4) other than the above (a3); and a polyether polyol (a5).

[0015] The urethane prepolymer (i) is a reaction product of a specific polyol (A) and a polyisocyanate (B).

[0016] The polyol (A) contains the above-mentioned (a1) to (a5) as essential components.

[0017] In order to exhibit excellent initial strength and suppress penetration, the aromatic polyester polyol (a1) must be made of a compound (x) having a molecular weight of less than 500, a branched structure, and 2 to 4 hydroxyl groups in one molecule. It should be noted that the molecular weight of the compound (x) is a value calculated from a chemical formula.

[0018] As the above-mentioned compound (x), for example, 2-methyl-1,5-pentanediol, 3-methyl-1,5-pentanediol, 2,2,4-trimethyl-1,3-pentanediol, 2,4-diethyl-1,5-pentanediol, 1,2-butanediol, 1,3-butanediol, 2-butyl-2-ethyl-1,3-propanediol, 1,2-propanediol, 2-methyl-1,3-propanediol, 2-ethyl-1,3-hexanediol, neopentyl glycol, 2-isopropyl-1,4-butanediol, 2,4-dimethyl-1,5-pentanediol, 2-ethyl-1,6-hexanediol, 3,5-heptanediol, 2-methyl-1,8-octanediol, trimethylolpropane, etc. can be used. These compounds can be used alone or in combination of two or more. Among these, neopentyl glycol is preferred from the aspect of obtaining a more excellent effect of suppressing penetration.

[0019] The amount of the compound (x) used is preferably in the range of 0.1 to 30% by mass, more preferably in the range of 0.2 to 20% by mass, and even more preferably in the range of 0.3 to 15% by mass, based on the total mass of the polyol (A) and the polyisocyanate (B), in order to maintain an excellent effect of suppressing penetration, have an appropriate viscosity, and obtain good flexibility of the cured film.

[0020] Specific examples of the aromatic polyester polyol (a1) include reaction products of a compound having two or more hydroxyl groups including the compound (x) and a polybasic acid.

[0021] As compounds having two or more hydroxyl groups other than the above-mentioned compound (x), for example, aliphatic compounds such as ethylene glycol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,7-heptanediol, 1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, 1,12-dodecanediol, diethylene glycol, triethylene glycol, and tetraethylene glycol can be used; alicyclic compounds such as cyclopentanediol, cyclohexanediol, cyclohexanedimethanol, hydrogenated bisphenol A, and their alkylene oxide adducts; aromatic compounds such as bisphenol A, bisphenol F, and their alkylene oxide (ethylene oxide, propylene oxide, butylene oxide, etc.) adducts can be used. These compounds can be used alone or in combination of two or more. Among these, aliphatic compounds are preferred, and diethylene glycol is more preferred, from the perspective of obtaining a more excellent penetration suppression effect and flexibility.

[0022] As the above-mentioned polyacid, for example, phthalic acid, isophthalic acid, terephthalic acid, phthalic anhydride, etc. can be used. As other polyacids, for example, aromatic polyacids such as oxalic acid, malonic acid, succinic acid, adipic acid, sebacic acid, azelaic acid, 1,12-dodecanedicarboxylic acid, succinic acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, decanedioic acid, dodecanedioic acid, eicosanedioic acid, citraconic acid, itaconic acid, citraconic anhydride, itaconic anhydride, etc. can be used. These polyacids can be used alone or in combination of two or more. Among these, aromatic polyacids are preferred from the perspective of obtaining a more excellent penetration-inhibiting effect, adhesion, reactivity, and flexibility, and phthalic acid (a compound selected from one or more of phthalic acid, isophthalic acid, terephthalic acid, and phthalic anhydride) is more preferred.

[0023] The number average molecular weight of the aromatic polyester polyol (a1) is more preferably 700 to 10,000, and more preferably 800 to 5,000, from the viewpoint of obtaining a more excellent penetration-inhibiting effect and flexibility. The number average molecular weight of the aromatic polyester polyol (a1) is a value measured by gel permeation chromatography (GPC).

[0024] The content of the aromatic polyester polyol (a1) is preferably 10 to 40% by mass, more preferably 15 to 30% by mass, in the polyol (A) in order to obtain a more excellent anti-breakthrough effect and flexibility.

[0025] The aromatic polyester polyol (a2) is a substance other than the aromatic polyester polyol (a1) (a substance not using the compound (x) as a raw material), and is used to extend the bonding time and obtain excellent handling properties.

[0026] As the raw material of the aromatic polyester polyol (a2), the compound having two or more hydroxyl groups and the polybasic acid which can be used as the raw material of the aromatic polyester polyol (a1) can be used. The compound having two or more hydroxyl groups is preferably an aliphatic compound, and the polybasic acid preferably contains phthalic acid.

[0027] The number average molecular weight of the aromatic polyester polyol (a2) is more preferably 700 to 10,000, and more preferably 800 to 5,000. The number average molecular weight of the aromatic polyester polyol (a1) is a value measured by gel permeation chromatography (GPC).

[0028] The content of the aromatic polyester polyol (a2) is preferably 5 to 30% by mass, more preferably 10 to 25% by mass in the polyol (A).

[0029] The aliphatic polyester polyol (a3) ​​is used to adjust the curing time, and examples thereof include reaction products of an aliphatic compound having two or more hydroxyl groups and an aliphatic polybasic acid.

[0030] As the aliphatic compound having two or more hydroxyl groups, for example, the compound (x) mentioned above; aliphatic compounds such as ethylene glycol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,7-heptanediol, 1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, 1,12-dodecanediol, diethylene glycol, triethylene glycol, and tetraethylene glycol can be used. These compounds can be used alone or in combination of two or more. Among these, it is preferred to use the compound (x) and the aliphatic compound mentioned above in combination.

[0031] As the aliphatic polybasic acid, succinic acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, decanedioic acid, dodecanedioic acid, eicosanedioic acid, citraconic acid, itaconic acid, citraconic anhydride, itaconic anhydride, etc. can be used. These polybasic acids can be used alone or in combination of two or more.

[0032] The number average molecular weight of the aliphatic polyester polyol (a3) ​​is more preferably 700 to 50,000, and more preferably 800 to 7,000. The number average molecular weight of the aromatic polyester polyol (a1) is a value measured by gel permeation chromatography (GPC).

[0033] The content of the aliphatic polyester polyol (a3) ​​is preferably 5 to 30% by mass, more preferably 10 to 25% by mass in the polyol (A).

[0034] The crystalline polyester polyol (a4) is used to obtain excellent adhesiveness and is a substance other than the aliphatic polyester polyol (a3), and for example, a reaction product of a compound having a hydroxyl group and a polybasic acid can be used. It should be noted that in the present invention, "crystallinity" means that a peak of crystallization heat or melting heat can be confirmed in a DSC (differential scanning calorimeter) measurement in accordance with JIS K7121:2012.

[0035] As the above-mentioned compound with hydroxyl group, for example, ethylene glycol, propylene glycol, butanediol, pentanediol, hexanediol, heptanediol, octanediol, nonanediol, decanediol, trimethylolpropane, trimethylolethane, glycerol etc. can be used. These compounds can be used alone or in combination of two or more. Among these, from the aspect of improving crystallinity and obtaining more excellent adhesion, it is preferred to use one or more selected from butanediol, hexanediol, octanediol and decanediol.

[0036] As the polybasic acid, for example, oxalic acid, malonic acid, succinic acid, adipic acid, sebacic acid, azelaic acid, dodecanedioic acid, etc. can be used. These compounds may be used alone or in combination of two or more.

[0037] The number average molecular weight of the crystalline polyester polyol (a4) is preferably 600 to 50,000, more preferably 1,000 to 10,000, from the viewpoint of obtaining more excellent adhesiveness. The number average molecular weight of the crystalline polyester polyol (a4) is a value measured by gel permeation chromatography (GPC).

[0038] The content of the crystalline polyester polyol (a4) is preferably 5 to 30% by mass, more preferably 10 to 25% by mass in the polyol (A).

[0039] The polyether polyol (a5) is used to adjust the low viscosity and the laminating time. For example, polyalkylene glycols such as polyethylene glycol, polypropylene glycol, and polytetramethylene glycol can be used; derivatives of the polyalkylene glycols (for example, derivatives of alkyl-substituted tetrahydrofuran, derivatives of neopentyl glycol), etc. can be used. These polyether polyols can be used alone or in combination of two or more. Among these, polypropylene glycol and / or polytetramethylene glycol are preferred.

[0040] The number average molecular weight of the polyether polyol (a5) is preferably 300 to 10,000, and more preferably 350 to 4,000. The number average molecular weight of the polyether polyol (a5) is a value measured by gel permeation chromatography (GPC).

[0041] The content of the polyether polyol (a5) is preferably 10 to 50% by mass, more preferably 15 to 40% by mass in the polyol (A).

[0042] The polyol (A) contains the above-mentioned (a1) to (a5) as essential components, but other polyols may be used in combination as necessary.

[0043] Examples of the other polyols include polyester polyols other than the above (a1) to (a4), acrylic polyols, polycarbonate polyols, polybutadiene polyols, etc. These polyols may be used alone or in combination of two or more.

[0044] As the polyisocyanate (B), for example, aromatic polyisocyanates such as polymethylene polyphenyl polyisocyanate, diphenylmethane diisocyanate, carbodiimide-modified diphenylmethane diisocyanate, xylylene diisocyanate, phenylene diisocyanate, toluene diisocyanate, and naphthalene diisocyanate; aliphatic or alicyclic polyisocyanates such as hexamethylene diisocyanate, cyclohexane diisocyanate, isophorone diisocyanate, dicyclohexylmethane diisocyanate, and tetramethylxylylene diisocyanate can be used. These polyisocyanates can be used alone or in combination of two or more. Among these, aromatic polyisocyanates are preferred from the aspect of mechanical strength, and diphenylmethane diisocyanate is more preferred.

[0045] The urethane prepolymer (i) can be produced, for example, by adding dropwise the mixture of the polyol (A) to a reaction vessel containing the polyisocyanate (B), followed by heating, and reacting under the condition that the isocyanate groups of the polyisocyanate (B) are in excess relative to the hydroxyl groups of the polyol (A).

[0046] When producing the urethane prepolymer (i), the equivalent ratio of the isocyanate group of the polyisocyanate (B) to the hydroxyl group of the polyol (A) (isocyanate group / hydroxyl group) is preferably 1.5 to 5, more preferably 1.6 to 2.5.

[0047] The isocyanate group content (hereinafter referred to as "NCO%") of the urethane prepolymer (i) is preferably 1.0 to 5.0% by mass, and more preferably 2.3 to 4.8% by mass. The NCO% of the urethane prepolymer (i) is a value measured by potentiometric titration in accordance with JIS K1603-1:2007.

[0048] The moisture-curable polyurethane hot-melt resin composition of the present invention contains the above-mentioned urethane prepolymer (i) as an essential component, but may contain other additives as necessary.

[0049] As the above-mentioned other additives, for example, curing catalysts, antioxidants, tackifiers, plasticizers, stabilizers, flame retardants, fillers, dyes, pigments, fluorescent whitening agents, silane coupling agents, waxes, thermoplastic resins, etc. can be used. These additives can be used alone or in combination of two or more.

[0050] The laminate of the present invention comprises a polyurethane foam, a cured product layer of the moisture-curable polyurethane hot-melt resin composition, and a base fabric.

[0051] The polyurethane foam imparts cushioning properties, vibration damping properties, air permeability, etc., and a known polyurethane foam can be used. The thickness of the polyurethane foam is, for example, in the range of 1.5 to 20 mm.

[0052] The base fabric is a base fabric that is bonded to the polyurethane foam and imparts sliding properties when placed on a molded product such as a car seat to improve workability, and examples thereof include nonwoven fabrics, woven fabrics, and knitted fabrics formed from polyester fibers, polyethylene fibers, nylon fibers, acrylic fibers, polyurethane fibers, acetate fibers, rayon fibers, polylactic acid fibers, cotton, linen, silk, wool, glass fibers, carbon fibers, and blended fibers thereof. It should be noted that in the present invention, by using the moisture-curable polyurethane hot-melt resin composition, an excellent penetration-inhibiting effect can be obtained even when a base fabric of a mesh fabric is used.

[0053] As a method for manufacturing the above-mentioned laminated body, for example, there can be mentioned a method of coating the above-mentioned moisture-curable polyurethane hot-melt resin composition on the above-mentioned polyurethane foam. As a method for coating the above-mentioned moisture-curable polyurethane hot-melt resin composition, for example, there can be mentioned a method using a coating machine such as a gravure coater, a roll coater, a spray coater, a T-die coater, a knife coater, a comma coater, etc.; a precision method such as a dispenser, inkjet printing, screen printing, offset printing, etc.; nozzle coating; spray coating; film lamination method, etc. Among these, intermittent coating is preferred from the perspective of obtaining better mechanical strength, bonding strength and penetration suppression effect. Before the above-mentioned coating, the above-mentioned moisture-curable polyurethane hot-melt resin composition can be melted at 70 to 120°C.

[0054] The coating amount of the moisture-curable polyurethane hot-melt resin composition may be, for example, 5 to 35 g / m 2 .

[0055] After the moisture-curable polyurethane hot-melt resin composition is applied, the composition may be cooled in order to accelerate the curing speed of the moisture-curable polyurethane hot-melt resin composition.

[0056] After the moisture-curable polyurethane hot-melt resin composition is cured, a release paper or a carrier sheet may be placed on the cured product. When used as a surface material, it is preferably peeled off.

[0057] The thickness of the cured product of the moisture-curable polyurethane hot-melt resin composition may be, for example, in the range of 5 to 200 μm.

[0058] The laminate of the present invention can be particularly suitably used as a skin material because of the above effects. As the composition of the skin material, for example, a composition in which the above base fabric, the above cured layer of the moisture-curable polyurethane hot-melt resin composition, the above polyurethane foam and the above skin layer are laminated can be cited.

[0059] A base fabric may be further provided between the polyurethane foam and the skin layer as required, and they may be bonded together using a known adhesive, such as an acrylic adhesive, a urethane adhesive, a moisture-curable polyurethane hot melt adhesive, and the like.

[0060] The skin layer may be formed of a known material, for example, solvent-based polyurethane, water-based polyurethane, polyvinyl chloride, thermoplastic urethane (TPU), thermoplastic polyolefin (TPO), thermoplastic polyester (TPE), etc. may be used.

[0061] The above-mentioned skin material can cover, for example, a seat of a vehicle.

[0062] Example

[0063] Hereinafter, the present invention will be described in more detail using examples.

[0064] [Example 1] Preparation of moisture-curable polyurethane hot-melt resin composition (1)

[0065] In a four-necked flask equipped with a thermometer, a stirrer, an inert gas inlet and a reflux condenser, 35 parts by mass of an aromatic polyester polyol (a reaction product of neopentyl glycol, diethylene glycol and phthalic anhydride, number average molecular weight: 1,000, hereinafter referred to as "aromatic PEs (a1-1)"), 15 parts by mass of an aromatic polyester polyol (a reaction product of hexanediol and phthalic anhydride, number average molecular weight: 2,000, hereinafter referred to as "aromatic PEs (a2-1)"), and 15 parts by mass of an aliphatic polyester polyol (a reaction product of ethylene glycol, neopentyl glycol, hexanediol and adipic acid) were added. The mixture was mixed with 10 parts by mass of a reaction product (number average molecular weight: 5,500, hereinafter referred to as “aliphatic PEs (a3-1)”), 15 parts by mass of a crystalline polyester polyol (a reaction product of 1,6-hexanediol and adipic acid, number average molecular weight: 8,000, hereinafter referred to as “crystalline PEs (a4-1)”), and 15 parts by mass of a polyether polyol (polypropylene glycol, number average molecular weight: 2,000, hereinafter referred to as “PEt (a5-1)”), and heated under reduced pressure at 70°C to perform dehydration until the water content in the flask becomes 0.05% by mass or less. Next, the flask was cooled to 90°C, 22 parts by mass of 4,4'-diphenylmethane diisocyanate (hereinafter referred to as "MDI") melted at 70°C was added, and the mixture was reacted at 110°C for about 3 hours under a nitrogen atmosphere until the isocyanate group content became constant, thereby obtaining a hot-melt urethane prepolymer (i-1) having an NCO% of 2.5% by mass, and preparing a moisture-curable polyurethane hot-melt resin composition (1).

[0066] [Example 2] Preparation of moisture-curable polyurethane hot-melt resin composition (2)

[0067] In a four-necked flask equipped with a thermometer, a stirrer, an inert gas inlet and a reflux condenser, 25 parts by mass of aromatic PEs (a1-1), 10 parts by mass of aromatic PEs (a2-1), 10 parts by mass of aliphatic PEs (a3-1), 10 parts by mass of crystalline PEs (a4-1), 10 parts by mass of PEt (a5-1) and 15 parts by mass of polyether polyol (polypropylene glycol, number average molecular weight: 400, hereinafter abbreviated as "PEt (a5-2)") were added and mixed, and heated under reduced pressure at 70°C to dehydrate until the water content in the flask became 0.05% by mass or less. Next, the flask was cooled to 90°C, 33 parts by mass of MDI melted at 70°C was added, and the mixture was reacted at 110°C for about 3 hours under a nitrogen atmosphere until the isocyanate group content became constant, thereby obtaining a hot-melt urethane prepolymer (i-2) having an NCO% of 4.0% by mass, and preparing a moisture-curable polyurethane hot-melt resin composition (2).

[0068] [Example 3] Preparation of moisture-curable polyurethane hot-melt resin composition (3)

[0069] In a four-necked flask equipped with a thermometer, a stirrer, an inert gas inlet and a reflux condenser, 35 parts by mass of aromatic PEs (a1-1), 15 parts by mass of aromatic PEs (a2-1), 10 parts by mass of aliphatic PEs (a3-1), 15 parts by mass of crystalline PEs (a4-1), and 15 parts by mass of polyether polyol (polytetramethylene glycol, number average molecular weight: 2,000, hereinafter referred to as "PEt (a5-3)") were added, mixed, and heated under reduced pressure at 70°C to dehydrate until the water content in the flask became 0.05% by mass or less. Next, the flask was cooled to 90°C, 22 parts by mass of MDI melted at 70°C was added, and the mixture was reacted at 110°C for about 3 hours under a nitrogen atmosphere until the isocyanate group content became constant, thereby obtaining a hot-melt urethane prepolymer (i-3) having an NCO% of 2.5% by mass, and a moisture-curable polyurethane hot-melt resin composition (3) was prepared.

[0070] [Example 4] Preparation of moisture-curable polyurethane hot-melt resin composition (4)

[0071] In a four-necked flask equipped with a thermometer, a stirrer, an inert gas inlet and a reflux condenser, 15 parts by mass of aromatic PEs (a1-1), 35 parts by mass of aromatic PEs (a2-1), 10 parts by mass of aliphatic PEs (a3-1), 15 parts by mass of crystalline PEs (a4-1) and 15 parts by mass of PEt (a5-1) were added, mixed, and heated under reduced pressure at 70°C to dehydrate until the water content in the flask became 0.05% by mass or less. Next, the flask was cooled to 90°C, 25 parts by mass of MDI melted at 70°C was added, and the mixture was reacted at 110°C for about 3 hours under a nitrogen atmosphere until the isocyanate group content became constant, thereby obtaining a hot-melt urethane prepolymer (i-4) having an NCO% of 4.0% by mass, and preparing a moisture-curable polyurethane hot-melt resin composition (4).

[0072] [Example 5] Preparation of moisture-curable polyurethane hot-melt resin composition (5)

[0073] In a four-necked flask equipped with a thermometer, a stirrer, an inert gas inlet and a reflux condenser, 35 parts by mass of aromatic PEs (a1-1), 15 parts by mass of aromatic PEs (a2-1), 10 parts by mass of aliphatic polyester polyol (a reaction product of neopentyl glycol, diethylene glycol, hexylene glycol and adipic acid, number average molecular weight: 2,000, hereinafter referred to as "aliphatic PEs (a3-2)"), 15 parts by mass of crystalline PEs (a4-1) and 15 parts by mass of PEt (a5-1) were added and mixed, and heated under reduced pressure at 70°C to dehydrate until the water content in the flask became 0.05% by mass or less. Next, the flask was cooled to 90°C, 22 parts by mass of MDI melted at 70°C was added, and the mixture was reacted at 110°C for about 3 hours under a nitrogen atmosphere until the isocyanate group content reached a constant, thereby obtaining a hot-melt urethane prepolymer (i-5) having an NCO% of 2.3% by mass, and preparing a moisture-curable polyurethane hot-melt resin composition (5).

[0074] [Example 6] Preparation of moisture-curable polyurethane hot-melt resin composition (6)

[0075] In a four-necked flask equipped with a thermometer, a stirrer, an inert gas inlet and a reflux condenser, 20 parts by mass of aromatic PEs (a1-1), 10 parts by mass of aromatic PEs (a2-1), 10 parts by mass of aliphatic PEs (a3-1), 10 parts by mass of crystalline PEs (a4-1) and 40 parts by mass of PEt (a5-1) were added, mixed, and heated under reduced pressure at 70°C to dehydrate until the water content in the flask became 0.05% by mass or less. Next, the flask was cooled to 90°C, 26 parts by mass of MDI melted at 70°C was added, and the mixture was reacted at 110°C for about 3 hours under a nitrogen atmosphere until the isocyanate group content became constant, thereby obtaining a hot-melt urethane prepolymer (i-6) having an NCO% of 4.0% by mass, and a moisture-curable polyurethane hot-melt resin composition (6) was prepared.

[0076] [Example 7] Preparation of moisture-curable polyurethane hot-melt resin composition (7)

[0077] In a four-necked flask equipped with a thermometer, a stirrer, an inert gas inlet and a reflux condenser, 35 parts by mass of aromatic PEs (a1-1), 15 parts by mass of aromatic polyester polyol (a reaction product of ethylene glycol, adipic acid, phthalic anhydride and terephthalic acid, number average molecular weight: 2,000, hereinafter referred to as "aromatic PEs (a2-2)"), 10 parts by mass of aliphatic PEs (a3-1), 10 parts by mass of crystalline PEs (a4-1) and 15 parts by mass of PEt (a5-1) were added and mixed, and heated under reduced pressure at 70°C to dehydrate until the water content in the flask became 0.05% by mass or less. Next, the flask was cooled to 90°C, 27 parts by mass of MDI melted at 70°C was added, and the mixture was reacted at 110°C for about 3 hours under a nitrogen atmosphere until the isocyanate group content reached a constant, thereby obtaining a hot-melt urethane prepolymer (i-7) having an NCO% of 4.0% by mass, and preparing a moisture-curable polyurethane hot-melt resin composition (7).

[0078] [Comparative Example 1] Preparation of moisture-curable polyurethane hot-melt resin composition (R1)

[0079] In a four-necked flask equipped with a thermometer, a stirrer, an inert gas inlet and a reflux condenser, 15 parts by mass of an aromatic polyester polyol (a reaction product of neopentyl glycol and phthalic anhydride, number average molecular weight: 1,000, hereinafter referred to as "aromatic PEs (a1-2)"), 35 parts by mass of a crystalline polyester polyol (a reaction product of hexanediol and sebacic acid, number average molecular weight: 4,000, hereinafter referred to as "crystalline PEs (a4-2)") and 50 parts by mass of PEt (a5-1) were added and mixed, and heated under reduced pressure at 70°C to perform dehydration until the water content in the flask became 0.05% by mass or less. Next, the flask was cooled to 90°C, 24 parts by mass of MDI melted at 70°C was added, and the mixture was reacted at 110°C for about 3 hours under a nitrogen atmosphere until the isocyanate group content became constant, thereby obtaining a hot-melt urethane prepolymer (iR-1) having an NCO% of 3.2% by mass, and preparing a moisture-curable polyurethane hot-melt resin composition (R1).

[0080] [Comparative Example 2] Preparation of moisture-curable polyurethane hot-melt resin composition (R2)

[0081] In a four-necked flask equipped with a thermometer, a stirrer, an inert gas inlet and a reflux condenser, 20 parts by mass of crystalline PEs (a4-2) and 80 parts by mass of PEt (a5-1) were added, mixed, and heated under reduced pressure at 70°C to dehydrate until the water content in the flask became 0.05% by mass or less. Next, the flask was cooled to 90°C, 18 parts by mass of MDI melted at 70°C was added, and the mixture was reacted at 110°C under a nitrogen atmosphere for about 3 hours until the isocyanate group content became constant, thereby obtaining a hot-melt urethane prepolymer (iR-2) with an NCO% of 1.9% by mass, and preparing a moisture-curable polyurethane hot-melt resin composition (R2).

[0082] [Method for measuring number average molecular weight]

[0083] The number average molecular weight of the polyol used in the synthesis examples and the comparative synthesis examples refers to the value measured by the gel permeation column chromatography (GPC) method under the following conditions.

[0084] Measuring device: High-speed GPC device (Tosoh Corporation "HLC-8220GPC")

[0085] Column: The following columns manufactured by Tosoh Corporation were connected in series and used.

[0086] "TSKgel G5000" (7.8mm I.D. × 30cm) × 1 piece

[0087] "TSKgel G4000" (7.8mm I.D. × 30cm) × 1 piece

[0088] "TSKgel G3000" (7.8mm I.D. × 30cm) × 1 piece

[0089] "TSKgel G2000" (7.8mm I.D. × 30cm) × 1 piece

[0090] Detector: RI (differential refractometer)

[0091] Column temperature: 40°C

[0092] Eluent: Tetrahydrofuran (THF)

[0093] Flow rate: 1.0mL / min

[0094] Injection volume: 100 μL (tetrahydrofuran solution with a sample concentration of 0.4 mass %)

[0095] Standard samples: The following standard polystyrene was used to prepare a calibration curve.

[0096] (Standard Polystyrene)

[0097] "TSKgel Standard Polystyrene A-500" manufactured by Tosoh Corporation

[0098] "TSKgel Standard Polystyrene A-1000" manufactured by Tosoh Corporation

[0099] "TSKgel Standard Polystyrene A-2500" manufactured by Tosoh Corporation

[0100] "TSKgel Standard Polystyrene A-5000" manufactured by Tosoh Corporation

[0101] "TSKgel Standard Polystyrene F-1" manufactured by Tosoh Corporation

[0102] "TSKgel Standard Polystyrene F-2" manufactured by Tosoh Corporation

[0103] "TSKgel Standard Polystyrene F-4" manufactured by Tosoh Corporation

[0104] "TSKgel Standard Polystyrene F-10" manufactured by Tosoh Corporation

[0105] "TSKgel Standard Polystyrene F-20" manufactured by Tosoh Corporation

[0106] "TSKgel Standard Polystyrene F-40" manufactured by Tosoh Corporation

[0107] "TSKgel Standard Polystyrene F-80" manufactured by Tosoh Corporation

[0108] "TSKgel Standard Polystyrene F-128" manufactured by Tosoh Corporation

[0109] "TSKgel Standard Polystyrene F-288" manufactured by Tosoh Corporation

[0110] "TSKgel Standard Polystyrene F-550" manufactured by Tosoh Corporation

[0111] [Evaluation method of mechanical strength]

[0112] On a hot plate set at 110°C, the moisture-curable polyurethane hot-melt resin composition obtained in the examples and comparative examples that had been melted at 110°C for 1 hour was applied to a 100 μm thick release PET using a 50 μm applicator, and placed at an ambient temperature of 23°C and an ambient humidity of 50% for 3 days to obtain a film. The obtained film was cut into strips of 5 mm in width and 50 mm in length, and stretched using a tensile testing machine "Autograph AG-I" (manufactured by Shimadzu Corporation) at a temperature of 23°C and a crosshead speed of 300 mm / second to measure the 100% modulus (MPa) of the test piece. The distance between the chucks at this time was set to 40 mm.

[0113] [Evaluation method of initial strength]

[0114] In a constant temperature and humidity chamber adjusted to a temperature of 23°C and a humidity of 50±5%, on a hot plate set at a temperature of 110°C, the moisture-curable polyurethane hot-melt resin composition obtained in the examples and comparative examples was applied to a 100 μm thick corona-treated PET using a 100 μm applicator, and after being laminated to the corona-treated PET using a rubber roller, it was cut into 1 inch width for a specified time, and the tensile strength was measured using a tensile testing machine "Autograph AG-I" (manufactured by Shimadzu Corporation, H·S=200 mm / min).

[0115] [Evaluation method of adhesion and penetration inhibition]

[0116] The moisture-curable polyurethane hot-melt resin compositions obtained in Examples and Comparative Examples were coated with a gravure coater at a temperature of 20 ± 5 g / m 2The polyurethane foam was intermittently coated in a manner, and the nylon mesh on the back base fabric was laminated. After aging for 24 hours at an ambient temperature of 23°C and an ambient humidity of 50%, the adhesion was measured using a tensile tester "Autograph AG-I" (manufactured by Shimadzu Corporation, H·S=200mm / min) under a load of 2kg / A4 size. In addition, the penetration of the laminated product into the back base fabric mesh was visually confirmed. It should be noted that the situation where the moisture-curable polyurethane hot-melt resin composition did not penetrate was evaluated as "0", and the situation where it penetrated was evaluated as "×". It should be noted that "PUF" in the table represents polyurethane foam.

[0117]

[0118]

[0119] It is found that the moisture-curable polyurethane hot-melt resin composition of the present invention is excellent in mechanical strength, initial strength and adhesiveness, and can suppress penetration.

[0120] On the other hand, in Comparative Example 1, which is a method in which the aromatic polyester polyol (a2) and the aliphatic polyester polyol (a3) ​​are not used, the initial strength is low and there is penetration.

[0121] On the other hand, in Comparative Example 2, which is a method in which the aromatic polyester polyols (a1) and (a2) and the aliphatic polyester polyol (a3) ​​are not used, the initial strength is lower than that of Comparative Example 1, and there is penetration.

Claims

1. A moisture-curable polyurethane hot-melt resin composition, characterized in that: It contains a urethane prepolymer (i) having an isocyanate group which is a reaction product of a polyol (A) and a polyisocyanate (B), wherein the polyol (A) contains: an aromatic polyester polyol (a1) made from a compound (x) having a molecular weight of less than 500, a branched structure, and 2 to 4 hydroxyl groups in one molecule; an aromatic polyester polyol (a2) other than the aromatic polyester polyol (a1); an aliphatic polyester polyol (a3); a crystalline polyester polyol (a4) other than the aromatic polyester polyol (a3); and a polyether polyol (a5).

2. The moisture-curable polyurethane hot-melt resin composition according to claim 1, wherein The aromatic polyester polyol (a1) and the aromatic polyester polyol (a2) are both made from aromatic polyacids.

3. The moisture-curable polyurethane hot-melt resin composition according to claim 1, wherein The aliphatic polyester polyol (a3) ​​is prepared from a compound (x) having a molecular weight of less than 500, a branched structure, and 2 to 4 hydroxyl groups in one molecule as a raw material.

4. The moisture-curable polyurethane hot-melt resin composition according to claim 1, wherein The polyether polyol (a5) is polypropylene glycol and / or polytetramethylene glycol.

5. A solidified product, characterized in that: The present invention is formed from the moisture-curable polyurethane hot-melt resin composition according to claim 1.

6. A laminated body, characterized in that: The polyurethane foam comprises a polyurethane foam, the cured product layer according to claim 5, and a base fabric.

7. The laminate according to claim 6, wherein: The cured product layer of the moisture-curable polyurethane hot-melt resin composition is formed by intermittent coating.

8. The laminate according to claim 6, wherein: The base fabric is a mesh fabric.

9. The skin material according to claim 6, characterized in that: It is further provided with a skin layer.

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