Polyurethane resin-forming composition, urethane adhesive composition and cured product

Abstract

To provide a urethane resin-forming composition that contributes to the production of an adhesive having high toughness, a urethane adhesive composition, and a cured product of the urethane adhesive composition having high toughness.SOLUTION: There is provided a urethane resin-forming composition comprising a curing agent (A) and an isocyanate group-terminated prepolymer (B), wherein the curing agent (A) comprises an aliphatic or alicyclic diol (a-1), an amino alcohol (a-2), and a crosslinking agent (a-3) as an optional component, and the isocyanate group-terminated prepolymer (B) comprises a reaction product of a polyol (b-1) having a number average molecular weight of 2500 or more, a polyisocyanate (b-2), and a crosslinking agent (b-3) as an optional component, and wherein the urethane resin-forming composition comprises at least one of the crosslinking agent (a-3) and the crosslinking agent (b-3). R2-NH-R1-OH...Formula (1).SELECTED DRAWING: None

Description

[Technical field]

[0001] The present disclosure relates to a polyurethane resin-forming composition, a urethane adhesive composition, and a cured product. [Background technology]

[0002] There are various required properties for structural adhesives, such as those used in automobiles, etc. Among these, one property that has attracted particular attention is fracture toughness. Fracture toughness is considered to be a composite index of flexibility and rigidity, and is expressed as a unit of energy. A higher fracture toughness value means that the adhesive has better resistance when energy is applied (such as impact), so the higher the value, the better. Patent Document 1: A first liquid containing a prepolymer obtained by reacting a polyisocyanate with a polyol having a specific molecular weight, and a specific amount of a filler; and a second liquid containing a polyol having a specific molecular weight and a catalyst. Patent Document 1 discloses a urethane adhesive composition in which the number of moles of hydroxyl groups derived from a polyol in a first liquid and a polyol in a second liquid have a specific relationship. According to Patent Document 1, such a urethane adhesive composition not only provides good adhesive performance, but also has excellent storage stability. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] International Publication No. 2009 / 047962 Summary of the Invention [Problem to be solved by the invention]

[0004] However, although Patent Document 1 mentions tensile shear strength as adhesive performance, the fracture toughness value is insufficient, and there is a demand for an adhesive composition that achieves a high degree of both flexibility and rigidity.

[0005] Therefore, one aspect of the present disclosure is directed to providing a polyurethane resin-forming composition, a urethane adhesive composition, and a cured product of the urethane adhesive composition, which exhibit high fracture toughness values. [Means for solving the problem]

[0006] According to one embodiment of the present disclosure, the following embodiments [1] to

[14] and [1'] to [14'] are provided. [1] A hardener (A); A polyurethane resin-forming composition comprising an isocyanate group-terminated prepolymer (B), The curing agent (A) is an aliphatic or alicyclic diol (a-1); An amino alcohol (a-2) which is a compound represented by formula (1), and an optional crosslinking agent (a-3), The isocyanate group-terminated prepolymer (B) is A polyol (b-1) having a number average molecular weight of 2500 or more; Polyisocyanate (b-2), and an optional crosslinking agent (b-3), The polyurethane resin-forming composition includes at least one of the crosslinking agent (a-3) and the crosslinking agent (b-3): R 2 -NH-R 1 -OH...Formula (1) During the ceremony, R 1 teeth, At least one selected from the group consisting of a nitrogen atom, a carbon atom, an oxygen atom, and a hydrogen atom; It is linear or has a branched structure, and The linear portion has 10 or fewer carbon atoms; R 2 has an alicyclic structure, or an aromatic ring or a heteroaromatic ring. [2] The polyurethane resin-forming composition according to [1], wherein the resin obtained by curing the polyurethane resin-forming composition has a urethane group concentration of 2000 mmol / kg or more and 4500 mmol / kg or less. [3] The polyurethane resin-forming composition according to [1], wherein the total content of the crosslinkable groups in the crosslinking component (a-3) and the content of the crosslinkable groups in the crosslinking component (b-3) is 25 mmol / kg or more and 1000 mmol / kg or less in the polyurethane resin-forming composition. [4] The polyurethane resin-forming composition has a urethane group concentration of 2000 mmol / kg or more and 4500 mmol / kg or less in the resin obtained by curing the polyurethane resin-forming composition; The polyurethane resin-forming composition according to [1], wherein the total content of the crosslinkable group in the crosslinking component (a-3) and the content of the crosslinkable group in the crosslinking component (b-3) is 25 mmol / kg or more and 1000 mmol / kg or less in the polyurethane resin-forming composition. [5] The polyurethane resin-forming composition according to any one of [1] to [4], wherein the content of the amino alcohol (a-2) in the polyurethane resin-forming composition is 40 mmol / kg or more and 600 mmol / kg or less. [6] The polyurethane resin-forming composition has a urethane group concentration of 2000 mmol / kg or more and 4500 mmol / kg or less. The polyurethane resin-forming composition according to any one of [1] to [4], wherein the content of the amino alcohol (a-2) in the polyurethane resin-forming composition is 40 mmol / kg or more and 600 mmol / kg or less. [7] the total content of the crosslinkable group in the crosslinking component (a-3) and the content of the crosslinkable group in the crosslinking component (b-3) is 25 mmol / kg or more and 1000 mmol / kg or less in the polyurethane resin-forming composition; The polyurethane resin-forming composition according to any one of [1] to [6], wherein the content of the amino alcohol (a-2) in the polyurethane resin-forming composition is 40 mmol / kg or more and 600 mmol / kg or less. [8] The polyurethane resin-forming composition has a urethane group concentration of 2000 mmol / kg or more and 4500 mmol / kg or less. the total content of the crosslinkable group in the crosslinking component (a-3) and the content of the crosslinkable group in the crosslinking component (b-3) is 25 mmol / kg or more and 1000 mmol / kg or less in the polyurethane resin-forming composition, the content of the amino alcohol (a-2) in the polyurethane resin-forming composition is 40 mmol / kg or more and 600 mmol / kg or less; The polyurethane resin-forming composition according to any one of [1] to [7]. [9] The polyurethane resin-forming composition according to any one of [1] to [8], further comprising a filler (C).

[10] The polyurethane resin-forming composition according to any one of [1] to [9], wherein at least one of the curing agent (A) and the isocyanate group-terminated prepolymer (B) is liquid at 25°C and 1 atmospheric pressure.

[11] The polyurethane resin-forming composition according to any one of [1] to

[10] , wherein the curing agent (A) and the isocyanate group-terminated prepolymer (B) are both liquid at 25° C. and 1 atmospheric pressure.

[12] A urethane adhesive composition comprising the polyurethane resin-forming composition according to any one of [1] to

[11] .

[13] The urethane adhesive composition according to

[12] , wherein the solvent content is 1.0 mass % or less.

[14] A cured product of the urethane adhesive composition according to

[12] or

[13] . [1'] a curing agent (A), A polyurethane resin-forming composition comprising an isocyanate-terminated prepolymer (B), The curing agent (A) is an aliphatic or alicyclic diol (a-1); An amino alcohol (a-2) which is a compound represented by formula (1), and an optional crosslinking agent (a-3), The isocyanate group-terminated prepolymer (B) is A polyol (b-1) having a number average molecular weight of 2500 or more; Polyisocyanate (b-2), and an optional crosslinking agent (b-3), The polyurethane resin-forming composition includes at least one of the crosslinking agent (a-3) and the crosslinking agent (b-3): R 2 -NH-R 1 -OH...Formula (1) During the ceremony, R 1 teeth, At least one selected from the group consisting of a nitrogen atom, a carbon atom, an oxygen atom, and a hydrogen atom; It is linear or has a branched structure, and The linear portion has 10 or fewer carbon atoms; R 2 teeth, having a branched hydrocarbon group, or It has an alicyclic structure, an aromatic ring, or a heteroaromatic ring. [2'] The polyurethane resin-forming composition according to [1'], wherein the resin obtained by curing the polyurethane resin-forming composition has a urethane group concentration of 2000 mmol / kg or more and 4500 mmol / kg or less. [3'] The polyurethane resin-forming composition according to [1'], wherein the total content of the crosslinkable groups in the crosslinking component (a-3) and the content of the crosslinkable groups in the crosslinking component (b-3) is 25 mmol / kg or more and 1000 mmol / kg or less in the polyurethane resin-forming composition. [4'] the urethane group concentration of the resin obtained by curing the polyurethane resin-forming composition is 2000 mmol / kg or more and 4500 mmol / kg or less; The polyurethane resin-forming composition according to [1'], wherein the total content of the crosslinkable groups in the crosslinking component (a-3) and the content of the crosslinkable groups in the crosslinking component (b-3) is 25 mmol / kg or more and 1000 mmol / kg or less in the polyurethane resin-forming composition. [5'] The polyurethane resin-forming composition according to any one of [1'] to [4'], wherein the content of the amino alcohol (a-2) in the polyurethane resin-forming composition is 40 mmol / kg or more and 600 mmol / kg or less. [6'] the urethane group concentration of the resin obtained by curing the polyurethane resin-forming composition is 2000 mmol / kg or more and 4500 mmol / kg or less; The polyurethane resin-forming composition according to any one of [1'] to [4'], wherein the content of the amino alcohol (a-2) in the polyurethane resin-forming composition is 40 mmol / kg or more and 600 mmol / kg or less. [7'] the total content of the crosslinkable group in the crosslinking component (a-3) and the content of the crosslinkable group in the crosslinking component (b-3) is 25 mmol / kg or more and 1000 mmol / kg or less in the polyurethane resin-forming composition, The polyurethane resin-forming composition according to any one of [1'] to [6'], wherein the content of the amino alcohol (a-2) in the polyurethane resin-forming composition is 40 mmol / kg or more and 600 mmol / kg or less. [8'] The polyurethane resin-forming composition has a urethane group concentration of 2000 mmol / kg or more and 4500 mmol / kg or less in the resin obtained by curing the polyurethane resin-forming composition; the total content of the crosslinkable group in the crosslinking component (a-3) and the content of the crosslinkable group in the crosslinking component (b-3) is 25 mmol / kg or more and 1000 mmol / kg or less in the polyurethane resin-forming composition, the content of the amino alcohol (a-2) in the polyurethane resin-forming composition is 40 mmol / kg or more and 600 mmol / kg or less; The polyurethane resin-forming composition according to any one of the items [1'] to [7']. [9'] The polyurethane resin-forming composition according to any one of [1'] to [8'], further comprising a filler (C). [10'] The polyurethane resin-forming composition according to any one of [1'] to [9'], wherein at least one of the curing agent (A) and the isocyanate group-terminated prepolymer (B) is liquid at 25°C and 1 atmospheric pressure. [11'] The polyurethane resin-forming composition according to any one of [1'] to [10'], wherein the curing agent (A) and the isocyanate group-terminated prepolymer (B) are both liquid at 25°C and 1 atmospheric pressure. [12'] A urethane adhesive composition comprising the polyurethane resin-forming composition according to any one of [1'] to [11']. [13'] The urethane adhesive composition according to [12'], wherein the solvent content is 1.0 mass% or less. [14'] A cured product of the urethane adhesive composition according to [12'] or [13']. Effect of the Invention

[0007] According to one aspect of the present disclosure, it is possible to provide a polyurethane resin-forming composition, a urethane adhesive composition, and a cured product of the urethane adhesive composition, which exhibit high fracture toughness values. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] Exemplary embodiments for implementing each aspect of the present disclosure will now be described in detail. In this specification, a numerical range indicated using "~" indicates a range that includes the numerical values ​​before and after "~" as the minimum and maximum values, respectively. The minimum or maximum value of a numerical range indicated using "~", "greater than or equal to", or "less than or equal to" can be arbitrarily combined with the maximum or minimum value of another numerical range indicated using "~", "greater than or equal to", or "less than or equal to". Furthermore, the upper and lower limit values ​​indicated individually can also be arbitrarily combined.

[0009] [Polyurethane-forming composition] A polyurethane-forming composition according to one embodiment of the present disclosure comprises: A hardener (A); A polyurethane resin-forming composition comprising an isocyanate group-terminated prepolymer (B), The curing agent (A) is an aliphatic or alicyclic diol (a-1); An amino alcohol (a-2) which is a compound represented by formula (1), and an optional crosslinking agent (a-3), The isocyanate group-terminated prepolymer (B) is A polyol (b-1) having a number average molecular weight of 2500 or more; Polyisocyanate (b-2), and an optional crosslinking agent (b-3), The polyurethane resin-forming composition includes at least one of the crosslinking agent (a-3) and the crosslinking agent (b-3): R 2 -NH-R 1 -OH...Formula (1) During the ceremony, R 1 teeth, At least one selected from the group consisting of a nitrogen atom, a carbon atom, an oxygen atom, and a hydrogen atom; It is linear or has a branched structure, and The linear portion has 10 or fewer carbon atoms; R 2 teeth, having a branched hydrocarbon group, or It has an alicyclic structure, an aromatic ring, or a heteroaromatic ring.

[0010] The polyurethane resin-forming composition is A hardener (A); and an isocyanate-terminated prepolymer (B).

[0011] [[Hardening agent (A)]] The hardener (A) is an aliphatic or alicyclic diol (a-1); An amino alcohol (a-2) which is a compound represented by formula (1), and an optional crosslinking agent (a-3).

[0012] Examples of aliphatic diols include ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,8-octanediol, 1,9-nonanediol, 3-methyl-1,5-pentanediol, 3,3-dimethylolheptane, neopentyl glycol, diethylene glycol, and dipropylene glycol.

[0013] Examples of alicyclic diols include 1,4-cyclohexanediol, cycloheptanediol, cyclooctanediol, 1,4-cyclohexanedimethanol, hydroxypropylcyclohexanol, isohexide, tricyclo5.2.1.02,6decane-4,8-dimethanol, and alkylene oxide adducts thereof.

[0014] The diol (a-1) may contain only one of these, or may contain two or more of them.

[0015] The diol (a-1) preferably has a number average molecular weight of 500 g / mol or less, more preferably 250 g / mol or less.

[0016] The content of the diol (a-1) in the polyurethane resin-forming composition is preferably 150 mmol / kg or more and 2000 mmol / kg or more, and more preferably 200 mmol / kg or more and 1500 mmol / kg or less.

[0017] The number average molecular weight in the present disclosure may be any value that can be obtained by a highly accurate measurement method, and for example, a value measured by a method (titration method) in accordance with JIS K 0070-1992 may be used.

[0018] The curing agent (A) contains an amino alcohol (a-2) which is a compound represented by formula (1). The amino alcohol (a-2) is an amino alcohol (a-2-1) having a hydrocarbon group with a branched structure, or an amino alcohol (a-2-2) having a ring structure, which is a compound represented by formula (1): R 2 -NH-R 1 -OH...Formula (1) During the ceremony, R 1 teeth, At least one selected from the group consisting of a nitrogen atom, a carbon atom, an oxygen atom, and a hydrogen atom; It is linear or has a branched structure, and The linear portion has 10 or fewer carbon atoms; R 2 teeth, having a branched hydrocarbon group, or It has an alicyclic structure, an aromatic ring, or a heteroaromatic ring.

[0019] By containing the amino alcohol represented by formula (1) in the curing agent (A), the fracture toughness value (G 1c ) is high, and a polyurethane-forming composition having excellent toughness is obtained. The fracture toughness value is considered to be a composite index of flexibility and rigidity, and is expressed as a unit of energy. A higher fracture toughness value means that the adhesive has better resistance when energy is applied (such as to an impact), so the higher the fracture toughness value, the more preferable it is.

[0020] R 1 It is preferable that the alkyl group has a linear structure.

[0021] R 2 teeth, A hydrocarbon group having a branched structure, or It is preferable that the alkyl group is a hydrocarbon group having an alicyclic structure or an aromatic ring. R 2 The number of carbon atoms forming the branched hydrocarbon group is preferably 10 or less, and R 2 The number of carbon atoms forming the ring structure is preferably 10 or less.

[0022] Examples of the amino alcohol represented by formula (1) include 2-isopropylaminoethanol, 2-[(1-methylpropyl)amino]ethanol, 2-[(1-ethylpropyl)amino]ethanol, 2-[(1-methylbutyl)amino]ethanol, 2-[(1-methylhexyl)amino]ethanol, 2-[(1-methylpentyl)amino]ethanol, 2-[(1-ethylbutyl)amino]ethanol, 2-[(1-ethylpentyl)amino]ethanol, 2-[(1,2-dimethylpropyl)amino]ethanol, 3-[(1-methylethyl)amino]-1-propanol, 4-[(1-methylethyl)amino]-1-butanol, 2-anilinoethanol, 2-benzylaminoethanol, 2-phenylamino-1-propanol, 2-[(4-methylphenyl)amino]ethanol, 2-[(2-methylphenyl)amino]ethanol, 2-[(3-methylphenyl)amino]ethanol, 4-phenylamino-1-butanol, 5-phenylamino- 1-Pentanol, 2-Phenylamino-1-butanol, 3-Phenylamino-1-propanol, 2-Cyclohexylaminoethanol, 2-Cycloheptylaminoethanol, 2-Cyclopentylaminoethanol, 1-Cyclohexylamino-2-propanol, 3-Cyclohexylamino-1-propanol, 2-Cyclohexylamino-1-propanol, 2-Cyclooctylaminoethanol, 2-[(2-methylcyclohexyl)amino]ethanol, 2-[(3- [(methylcyclohexyl)amino]ethanol, 2-[(4-methylcyclohexyl)amino]ethanol, 4-cyclohexylaminobutanol, 2-cyclohexylamino-1-butanol, 3-cyclopentylamino-1-propanol, 1-cyclopentylamino-2-propanol, 4-cyclopentylamino-1-butanol, 2-[tetrahydro-2H-pyran-4-yl]amino]ethanol, 2-[tetrahydro-3-furanyl]amino]ethanol and the like.

[0023] The inventors speculate that the reason why amino alcohols represented by formula (1) are preferred is as follows. Dissociation of the secondary amine-derived structural portion improves energy consumption performance and fracture toughness. However, if this structural portion forms an aggregate, the toughness decreases because the embrittlement effect is greater than the energy consumption performance. In order not to form aggregates, the side chains need to be bulky, and the presence of a branched structure or a ring structure suppresses the formation of aggregates and improves energy consumption performance.

[0024] The content of the amino alcohol (a-2) in the polyurethane resin forming composition is preferably 10 mmol / kg or more and 1000 mmol / kg or less, more preferably 30 mmol / kg or more and 800 mmol / kg or less, even more preferably 40 mmol / kg or more and 600 mmol / kg or less, and particularly preferably 60 mmol / kg or more and 500 mmol / kg or less.

[0025] The curing agent (A) contains an optional crosslinking component (a-3), that is, the curing agent (A) may further contain the crosslinking component (a-3). An example of the crosslinking component (a-3) is a polyol having an average functionality of 3 or more. Examples of polyols having an average functionality of 3 or more include glycerin, trimethylolpropane, pentaerythritol, N,N-bishydroxypropyl-N-hydroxyethylamine, triethanolamine, triisopropanolamine, monomer polyols of ethylenediamine propylene oxide modified products, monomer polyols of trimethylolpropane propylene oxide modified products, and pentaerythritol propylene oxide modified products. In addition to these, examples of polycaprolactone polyols include those obtained by ring-opening addition of cyclic esters such as ε-caprolactone, β-butyrolactone, γ-butyrolactone, γ-valerolactone, and δ-valerolactone to polyols such as glycerin, trimethylolpropane, and pentaerythritol as initiators.

[0026] The crosslinking component (a-3) may contain only one of these, or may contain two or more of them.

[0027] The curing agent (A) preferably further contains a polyol (a-4) having a number average molecular weight of less than 1000. The polyol (a-4) more preferably has a number average molecular weight of less than 500.

[0028] The polyol (a-4) may be, for example, a polyol containing one or more bonds selected from the group consisting of an ester bond, an ether bond, and a carbonate bond. Polyester polyol, polyether polyol, and polycarbonate polyol are more preferred, and polyether polyol is even more preferred.

[0029] Examples of polycarbonate polyols include ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,8-octanediol, 1,9-nonanediol, 3-methyl-1,5-pentanediol, 3,3-dimethylolheptane, diethylene glycol, dipropylene glycol, neopentyl glycol, cyclohexane-1,4-diol, cyclohexane-1,4-dimethanol, glycerin, trimethylolpropane, dimer Examples of such polyols include those obtained by a dealcoholization reaction or a dephenolization reaction between one or more polyols, such as diol acid, an ethylene oxide or propylene oxide adduct of bisphenol A, bis(β-hydroxyethyl)benzene, and xylylene glycol, and one or more carbonates, such as dialkyl carbonates, such as dimethyl carbonate and diethyl carbonate, alkylene carbonates, such as ethylene carbonate and propylene carbonate, diphenyl carbonate, dinaphthyl carbonate, dianthryl carbonate, diphenanthryl carbonate, and diindanyl carbonate.

[0030] Examples of polyester polyols include dicarboxylic acids such as phthalic acid, isophthalic acid, terephthalic acid, naphthalenedicarboxylic acid, succinic acid, tartaric acid, oxalic acid, malonic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, glutaconic acid, azelaic acid, sebacic acid, 1,4-cyclohexyldicarboxylic acid, α-hydromuconic acid, β-hydromuconic acid, α-butyl-α-ethylglutaric acid, α,β-diethylsuccinic acid, maleic acid, and fumaric acid, and anhydrides thereof; and polyester polyols such as ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,2-butanediol, 1,3-butanediol, 1,4 Examples of the polyol (b-1) include those obtained by a condensation polymerization reaction of one or more of the following alcohols with the alcohols: 1,5-butanediol, 1,6-hexanediol, 1,8-octanediol, 1,9-nonanediol, 3-methyl-1,5-pentanediol, 3,3-dimethylolheptane, diethylene glycol, dipropylene glycol, neopentyl glycol, cyclohexane-1,4-diol, cyclohexane-1,4-dimethanol, glycerin, trimethylolpropane, diol dimer acid, ethylene oxide or propylene oxide adduct of bisphenol A, bis(β-hydroxyethyl)benzene, xylylene glycol, etc. Examples of the polyol (b-1) include polyester-amide polyols obtained by replacing a part of these alcohols with low molecular weight polyamines or low molecular weight amino alcohols, such as hexamethylenediamine, isophoronediamine, and monoethanolamine.

[0031] Examples of polyether polyols include ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,8-octanediol, 1,9-nonanediol, 3-methyl-1,5-pentanediol, 3,3-dimethylolheptane, diethylene glycol, dipropylene glycol, neopentyl glycol, cyclohexane-1,4-diol, and cyclohexane-1,4-dimethanol. Examples of the polyether polyol include polyether polyols obtained by addition polymerization of alkylene oxides such as ethylene oxide, propylene oxide, butylene oxide, etc., using as an initiator a compound having two active hydrogen groups such as low molecular weight polyols such as dimer acid diol, bisphenol A, bis(β-hydroxyethyl)benzene, xylylene glycol, etc., or low molecular weight polyamines such as ethylene diamine, propylene diamine, toluene diamine, metaphenylene diamine, diphenylmethane diamine, xylylene diamine, etc. Examples of the polyether polyol include polyether polyols obtained by ring-opening polymerization of cyclic ether monomers such as alkyl glycidyl ethers such as methyl glycidyl ether, aryl glycidyl ethers such as phenyl glycidyl ether, and tetrahydrofuran.

[0032] Among these polyols (a-4), polyether polyols are particularly preferred.

[0033] The curing agent (A) is preferably liquid at 25° C. and 1 atmosphere.

[0034] The curing agent (A) may contain an active hydrogen-containing compound in addition to the polyol.

[0035] Such active hydrogen-containing compounds include, for example, compounds having functional groups such as amino groups, thiol groups, carboxyl groups, etc. These active hydrogen-containing compounds can be used alone or in combination of two or more.

[0036] [[Isocyanate-terminated prepolymer (B)]] The isocyanate-terminated prepolymer (B) is A polyol (b-1) having a number average molecular weight of 2500 or more; Polyisocyanate (b-2), It is a reaction product with an optional crosslinking agent (b-3).

[0037] Examples of the polyol (b-1) having a number average molecular weight of 2,500 or more include polyols having a number average molecular weight of 2,500 or more similar to the polyol (a-4).

[0038] Among these polyols (b-1), polyether polyols are particularly preferred.

[0039] The number average molecular weight of the polyol (b-1) is preferably 2,500 or more and 10,000 or less, and more preferably 2,500 or more and 7,000 or less.

[0040] The content of polyol (b-1) in the polyurethane resin-forming composition is preferably 10 mmol / kg or more and 300 mmol / kg or less, and more preferably 50 mmol / kg or more and 250 mmol / kg or less.

[0041] The polyisocyanate (b-2) may be a polyisocyanate having two or more isocyanate groups in the molecule. As the polyisocyanate, an organic polyisocyanate can be used, and examples of the organic polyisocyanate include aromatic polyisocyanate, araliphatic polyisocyanate, aliphatic polyisocyanate, and alicyclic polyisocyanate. These can be used alone or in combination of two or more. Among these, it is preferable to use aromatic polyisocyanate from the viewpoint of reactivity and viscosity.

[0042] Examples of aromatic polyisocyanates include 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, 2,4-tolylene diisocyanate / 2,6-tolylene diisocyanate mixture, 2,2'-diphenylmethane diisocyanate, 4,4'-diphenylmethane diisocyanate, 2,2'-diphenylmethane diisocyanate / 4,4'-diphenylmethane diisocyanate mixture, 2,4'-diphenylmethane diisocyanate, 2,4'-diphenylmethane diisocyanate / 4,4'-diphenylmethane diisocyanate mixture, 2,2'-diphenylmethane diisocyanate / 2,4'-diphenylmethane diisocyanate / Examples of the diisocyanate include 4,4'-diphenylmethane diisocyanate mixture, m-xylylene diisocyanate, p-xylylene diisocyanate, 4,4'-diphenylether diisocyanate, 2-nitrodiphenyl-4,4'-diisocyanate, 2,2'-diphenylpropane-4,4'-diisocyanate, 3,3'-dimethyldiphenylmethane-4,4'-diisocyanate, 4,4'-diphenylpropane diisocyanate, m-phenylene diisocyanate, p-phenylene diisocyanate, naphthylene-1,4-diisocyanate, naphthylene-1,5-diisocyanate, and 3,3'-dimethoxydiphenyl-4,4'-diisocyanate.

[0043] Examples of the aromatic aliphatic polyisocyanate include 1,3-xylylene diisocyanate, 1,4-xylylene diisocyanate, a mixture of 1,3-xylylene diisocyanate / 1,4-xylylene diisocyanate, 1,3-bis(1-isocyanato-1-methylethyl)benzene, 1,4-bis(1-isocyanato-1-methylethyl)benzene, a mixture of 1,3-bis(1-isocyanato-1-methylethyl)benzene / 1,4-bis(1-isocyanato-1-methylethyl)benzene, and ω,ω'-diisocyanato-1,4-diethylbenzene.

[0044] Examples of aliphatic polyisocyanates include tetramethylene diisocyanate, hexamethylene diisocyanate, 2-methylpentane-1,5-diisocyanate, 3-methylpentane-1,5-diisocyanate, lysine diisocyanate, trioxyethylene diisocyanate, ethylene diisocyanate, trimethylene diisocyanate, octamethylene diisocyanate, nonamethylene diisocyanate, 2,2'-dimethylpentane diisocyanate, 2,2,4-trimethylhexane diisocyanate, decamethylene diisocyanate, butene diisocyanate, 1,3-butadiene-1,4-diisocyanate, 2,4,4-trimethylhexamethylene diisocyanate, and 1,2,3,4-trimethylhexamethylene diisocyanate. Examples of the isocyanate include ethylene diisocyanate, 1,6,11-undecane triisocyanate, 1,3,6-hexamethylene triisocyanate, 1,8-diisocyanate-4-isocyanate methyl octane, 2,5,7-trimethyl-1,8-diisocyanate-5-isocyanate methyl octane, bis(isocyanate ethyl) carbonate, bis(isocyanate ethyl) ether, 1,4-butylene glycol dipropyl ether-α,α'-diisocyanate, lysine diisocyanate methyl ester, 2-isocyanate ethyl-2,6-diisocyanate hexanoate, and 2-isocyanate propyl-2,6-diisocyanate hexanoate.

[0045] Examples of alicyclic polyisocyanates include isophorone diisocyanate, cyclohexane diisocyanate, bis(isocyanatemethyl)cyclohexane, dicyclohexylmethane diisocyanate, methylcyclohexane diisocyanate, dicyclohexyldimethylmethane diisocyanate, 2,2'-dimethyldicyclohexylmethane diisocyanate, bis(4-isocyanate-n-butylidene)pentaerythritol, hydrogenated dimer acid diisocyanates, 2-isocyanatomethyl-3-(3-isocyanatopropyl)-5-isocyanatomethyl-bicyclo[2.2.1]-heptane, 2-isocyanatomethyl-3-(3-isocyanatopropyl)-6-isocyanatomethyl-bicyclo[2.2.1]-heptane, 2-isocyanatomethyl-2-(3-isocyanatopropyl)-5-isocyanatomethyl-bicyclo[2.2.1]-heptane, 2-isocyanatomethyl-2-(3-isocyanatopropyl)-6-isocyanatomethyl-bicyclo[2.2.1]-heptane 2-isocyanatomethyl-3-(3-isocyanatopropyl)-5-(2-isocyanatoethyl)-bicyclo-[2.2.1]-heptane, 2-isocyanatomethyl-3-(3-isocyanatopropyl)-6-(2-isocyanatoethyl)-bicyclo-[2.2.1]-heptane, 2-isocyanatomethyl-2-(3-isocyanatopropyl)-5-(2-isocyanatoethyl)-bicyclo-[2.2.1]-heptane Examples of isocyanate derivatives include 2-isocyanatemethyl-2-(3-isocyanatepropyl)-6-(2-isocyanateethyl)-bicyclo-[2.2.1]-heptane, 2,5-bis(isocyanatemethyl)-bicyclo[2.2.1]-heptane, hydrogenated diphenylmethane diisocyanate, norbornane diisocyanate, hydrogenated tolylene diisocyanate, hydrogenated hydrogenated xylene diisocyanate, and hydrogenated hydrogenated tetramethylxylene diisocyanate.

[0046] The polyisocyanate may be used alone or in combination of two or more thereof.

[0047] The content of the polyisocyanate (b-2) in the polyurethane resin-forming composition is preferably 500 mmol / kg or more and 3000 mmol / kg or less, and more preferably 750 mmol / kg or more and 2500 mmol / kg or less.

[0048] The isocyanate-terminated prepolymer (B) contains an optional crosslinking agent (b-3), that is, the isocyanate-terminated prepolymer (B) may further contain a crosslinking component (b-3). Examples of the cross-linking component (b-3) include the same as the cross-linking component (a-3).

[0049] Here, the crosslinking component may be contained in the polyurethane resin-forming composition in either one of the following (1) and (2), or may be contained in the polyurethane adhesive composition in either one of (1) and (2). (1) The curing agent (A) further contains a crosslinking component (a-3). (2) The isocyanate-terminated prepolymer (B) is A polyol (b-1) having a number average molecular weight of 2500 or more; Polyisocyanate (b-2), It is a reaction product with a crosslinking component (b-3).

[0050] The total content of the crosslinkable groups of the crosslinking components (a-3) and (b-3) (i.e., crosslink density) in the polyurethane resin forming composition is preferably 25 mmol / kg or more and 1000 mmol / kg or less, and particularly preferably 40 mmol / kg or more and 600 mmol / kg or less. If the content of the crosslinkable groups is in this range, the fracture toughness value (G1c) is high and the toughness is excellent, which is preferable.

[0051] Here, the crosslinkable group is a functional group that forms a crosslink. Therefore, in the case of a trifunctional polyol (e.g., glycerin), one hydroxyl group in one molecule forms a crosslink, and the remaining two hydroxyl groups do not contribute to the crosslinking, so in this case the number of crosslinkable groups is one. That is, in the case of a trifunctional polyol, the content of the crosslinkable group is synonymous with the content of the trifunctional polyol, since the trifunctional polyol has one crosslinkable group.

[0052] The isocyanate group-terminated prepolymer (B) is Polyether polyol (b-1), Polyisocyanate (b-2), A cross-linking component (b-3), and a diol (b-4) having a number average molecular weight of 250 or more and less than 1,000, is more preferred. As the diol (b-4), for example, a diol having a number average molecular weight of 250 or more and less than 1,000 similar to the polyol (a-4) can be mentioned.

[0053] At least one of the polyol (b-1) and the polyisocyanate (b-2) is preferably liquid at 25° C. and 1 atmospheric pressure.

[0054] At least one of the curing agent (A) and the isocyanate-terminated prepolymer (B) is preferably liquid at 25° C. and 1 atm. In addition, it is preferable that both the curing agent (A) and the isocyanate-terminated prepolymer (B) are liquid at 25° C. and 1 atm.

[0055] The curing agent (A) may contain other components, preferably those that do not react with the other components when the curing agent (A) is mixed with the isocyanate group-terminated prepolymer (B) (e.g., fillers, colorants, antistatic agents, preservatives). The isocyanate-terminated prepolymer (B) may contain other components, which are preferably those that do not react with the functional groups of the isocyanate-terminated prepolymer (B) and the curing agent (A) described below (e.g., fillers, colorants, antistatic agents, preservatives).

[0056] The urethane group concentration of the resin obtained by curing the polyurethane resin-forming composition is preferably 2000 mmol / kg or more and 4500 mmol / kg or less, and more preferably 2500 mmol / kg or more and 4000 mmol / kg or less.

[0057] From the viewpoint of handleability, the polyurethane resin-forming composition is preferably liquid (that is, has flowability) at 25° C. and 1 atmospheric pressure.

[0058] [[[Filler (C)]]] The polyurethane resin-forming composition preferably further contains a filler (C). Examples of the filler (C) include known fillers, such as inorganic fillers and organic fillers. Among these, inorganic fillers are preferred.

[0059] Examples of inorganic fillers include, but are not limited to, talc, zeolite, silica, microballoons, clay, glass balloons, carbon black, calcium carbonate, etc. These may be used alone or in combination of two or more.

[0060] Examples of the organic filler include polyamide particles, acrylic particles, carbon nanotubes, starch, natural organic fibers, and synthetic fibers.

[0061] The content of the filler is preferably from 10% by mass to 70% by mass, and more preferably from 10% by mass to 50% by mass, based on the total mass of the polyurethane resin-forming composition. When the filler content is 10% by mass or more, dripping can be suppressed more effectively. When the filler content is 70% by mass or less, the filler and other components are mixed more uniformly, and further improved adhesive strength and coatability can be obtained.

[0062] The polyurethane resin-forming composition contains a curing agent (A) and an isocyanate-terminated prepolymer (B). These may be a two-liquid type in which they are present separately, or a one-liquid type in which they are mixed. The temperature and time for mixing the curing agent (A) and the isocyanate-terminated prepolymer (B) may be, for example, 10 to 35°C and 1 to 60 minutes.

[0063] The method for mixing the curing agent (A) and the isocyanate group-terminated prepolymer (B) is not particularly limited, and may be, for example, a method in which they are mixed manually with a spatula, or a method in which they are mixed using a mechanical rotary mixer, a static mixer, or the like.

[0064] [Urethane adhesive composition, automotive structural adhesive] The urethane adhesive composition according to one embodiment of the present disclosure includes the polyurethane resin-forming composition described above. The polyurethane resin-forming composition can be preferably used for automobile structures.

[0065] The polyurethane adhesive composition preferably has a solvent content of 1.0 mass % or less. In addition, the polyurethane adhesive composition may be substantially free of solvent, i.e., solvent-free, although when a solvent is contained as an impurity, it falls into the category of being substantially free of solvent.

[0066] [Cured product] A cured product according to one embodiment of the present disclosure is a cured product of the polyurethane adhesive composition described above. EXAMPLES

[0067] The present invention will be described in more detail below based on examples, but the present invention is not limited to the following examples.

[0068] [Preparation of polyurethane resin-forming composition] The following compounds were mixed in the amounts shown in Tables 1 to 3 to prepare polyurethane resin-forming compositions. [Raw materials] "MT": Millionate MT (monomeric MDI, manufactured by Tosoh Corporation) Average molecular weight 250, f=2 "TMP": Trimethylolpropane (manufactured by Mitsubishi Gas Chemical Co., Ltd.) Trimethylolpropane, average molecular weight 134, f=3 "PTG-L3500": Amorphous polytetramethylene ether glycol (Hodogaya Chemical Co., Ltd.), Average molecular weight 3500, f=2 · "PTMG3000"; Polytetramethylene ether glycol (Mitsubishi Chemical Corporation), Average molecular weight 3000, f=2 "BG": Butylene glycol (manufactured by Mitsubishi Chemical Corporation) 1,4-butanediol, average molecular weight 90, f=2 "CHDM": 1,4-cyclohexanedimethanol (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) "Anilinoethanol": 2-anilinoethanol (Tokyo Chemical Industry Co., Ltd.) "Methylaminoethanol": 2-(methylamino)ethanol (Tokyo Chemical Industry Co., Ltd.) "Butylaminoethanol": 2-(butylamino)ethanol (Tokyo Chemical Industry Co., Ltd.) "Isopropylaminoethanol": 2-(isopropylamino)ethanol (Tokyo Chemical Industry Co., Ltd.) "Benzylaminoethanol": N-benzylaminoethanol (Tokyo Chemical Industry Co., Ltd.) "Cyclohexylaminoethanol": 2-(cyclohexylamino)ethanol (Tokyo Chemical Industry Co., Ltd.) "Methyldiethanolamine": N-methyldiethanolamine (Tokyo Chemical Industry Co., Ltd.) "p-TolylDEA": 2,2'-(p-Tolylimino)diethanol (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) "Zeolite": Zeolum A-3 (manufactured by Tosoh Corporation) "Talc": Crown Talc R (manufactured by Matsumura Sangyo Co., Ltd.)

[0069] (Examples 1 to 3, Comparative Examples 1 to 8) Each raw material of the curing agent was added to a 2 L stirring vessel filled with nitrogen according to the formulations shown in Tables 1 to 3 and stirred. While maintaining the temperature inside the stirring vessel at 70 to 80°C, the mixture was mixed and stirred for about 1 to 3 hours to obtain various curing agents (A).

[0070] In addition, each raw material of the main agent (isocyanate-terminated prepolymer) (B) was added to a 2 L stirring vessel filled with nitrogen and stirred according to the recipes shown in Tables 1 to 3. Thereafter, the urethane reaction was carried out for about 2 to 5 hours while maintaining the temperature inside the stirring vessel at 70 to 80°C, thereby obtaining various isocyanate-terminated prepolymers (B).

[0071] [DCB test (fracture toughness)] DCB testing was performed according to ASTM D3433-99. Resin thickness: Adjust with spacers to be 0.35 mm Spacers use Teflon tape Test piece shape: Contoured type Test substrate: S50C steel (electroless nickel plating) Test conditions: Pull at 2 mm / min, and calculate fracture toughness G1c based on the maximum load Calculation formula: G1c=[4L2(max)](m) / [EB2] L(max) Load:(N) E Young's modulus of base material (MPa): 208000 B Width of substrate (mm): 25.49 m constant (from contoured type): 3.54

[0072] The filler (C) (talc 50% by mass / zeolite 50% by mass) was added to the main component (isocyanate group-terminated prepolymer) (B) so that the amount of filler in the system was 1 / 3, and the mixture was mixed and degassed. After mixing for 30 seconds, the mixture was applied to a substrate and fixed with a clamp, and then cured by heat treatment at 120°C for 5 hours. To create a preliminary crack in the substrate, a 0.35 mm thick Teflon seal was attached 4.9 cm from the front end. In addition, to ensure a uniform thickness of the adhesive, a Teflon seal of the same thickness was attached approximately 2 cm from the rear end of the substrate. The fracture toughness values ​​(G 1c ) are shown in Tables 1 to 3.

[0073] [Cohesive failure rate] The broken surface of the sample was visually observed, and the proportion of the broken area in the adhesive layer was measured. The measurement results are shown in Tables 1 to 5. Cohesive failure: Resin layer is destroyed Interfacial failure: A state in which the resin has peeled off at the substrate interface

[0074] [Table 1]

[0075] [Table 2]

[0076] [Table 3]

[0077] [Table 4]

Claims

1. A curing agent (A); A polyurethane resin-forming composition comprising an isocyanate group-terminated prepolymer (B), The curing agent (A) is an aliphatic or alicyclic diol (a-1); An amino alcohol (a-2) which is a compound represented by formula (1), and an optional crosslinking agent (a-3), The isocyanate group-terminated prepolymer (B) is A polyol (b-1) having a number average molecular weight of 2,500 or more; Polyisocyanate (b-2), and an optional crosslinking agent (b-3), The polyurethane resin-forming composition includes at least one of the crosslinking agent (a-3) and the crosslinking agent (b-3): R 2 -NH-R 1 -OH ・・・Formula (1) During the ceremony, R 1 teeth, At least one selected from the group consisting of a nitrogen atom, a carbon atom, an oxygen atom, and a hydrogen atom; It is linear or has a branched structure, and The linear portion has 10 or less carbon atoms; R 2 has an alicyclic structure, or an aromatic ring or a heteroaromatic ring.

2. A curing agent (A); A polyurethane resin-forming composition comprising an isocyanate group-terminated prepolymer (B), The curing agent (A) is an aliphatic or alicyclic diol (a-1); An amino alcohol (a-2) which is a compound represented by formula (1), and an optional crosslinking agent (a-3), The isocyanate group-terminated prepolymer (B) is A polyol (b-1) having a number average molecular weight of 2,500 or more; Polyisocyanate (b-2), and an optional crosslinking agent (b-3), The polyurethane resin-forming composition includes at least one of the crosslinking agent (a-3) and the crosslinking agent (b-3): R 2 -NH-R 1 -OH ・・・Formula (1) During the ceremony, R 1 teeth, At least one selected from the group consisting of a nitrogen atom, a carbon atom, an oxygen atom, and a hydrogen atom; It is linear or has a branched structure, and The linear portion has 10 or less carbon atoms; R 2 teeth, having a branched hydrocarbon group, or It has an alicyclic structure, an aromatic ring, or a heteroaromatic ring.

3. 2. The polyurethane resin-forming composition according to claim 1, wherein the urethane group concentration of the resin obtained by curing the polyurethane resin-forming composition is 2000 mmol / kg or more and 4500 mmol / kg or less.

4. The polyurethane resin-forming composition according to claim 1, wherein the total content of the crosslinkable group in the crosslinking component (a-3) and the content of the crosslinkable group in the crosslinking component (b-3) is 25 mmol / kg or more and 1000 mmol / kg or less in the polyurethane resin-forming composition.

5. the polyurethane resin-forming composition is cured to obtain a resin having a urethane group concentration of 2000 mmol / kg or more and 4500 mmol / kg or less; The polyurethane resin-forming composition according to claim 1, wherein the total content of the crosslinkable group in the crosslinking component (a-3) and the content of the crosslinkable group in the crosslinking component (b-3) is 25 mmol / kg or more and 1000 mmol / kg or less in the polyurethane resin-forming composition.

6. 2. The polyurethane resin-forming composition according to claim 1, wherein the content of the amino alcohol (a-2) in the polyurethane resin-forming composition is 40 mmol / kg or more and 600 mmol / kg or less.

7. the polyurethane resin-forming composition is cured to obtain a resin having a urethane group concentration of 2000 mmol / kg or more and 4500 mmol / kg or less; The polyurethane resin-forming composition according to claim 1 , wherein the content of the amino alcohol (a-2) in the polyurethane resin-forming composition is 40 mmol / kg or more and 600 mmol / kg or less.

8. the total content of the crosslinkable group contained in the crosslinking component (a-3) and the content of the crosslinkable group contained in the crosslinking component (b-3) is 25 mmol / kg or more and 1000 mmol / kg or less in the polyurethane resin-forming composition, 2. The polyurethane resin-forming composition according to claim 1, wherein the content of the amino alcohol (a-2) in the polyurethane resin-forming composition is 40 mmol / kg or more and 600 mmol / kg or less.

9. the polyurethane resin-forming composition is cured to obtain a resin having a urethane group concentration of 2000 mmol / kg or more and 4500 mmol / kg or less; the total content of the crosslinkable group contained in the crosslinking component (a-3) and the content of the crosslinkable group contained in the crosslinking component (b-3) is 25 mmol / kg or more and 1000 mmol / kg or less in the polyurethane resin-forming composition, 2. The polyurethane resin-forming composition according to claim 1, wherein the content of the amino alcohol (a-2) in the polyurethane resin-forming composition is 40 mmol / kg or more and 600 mmol / kg or less.

10. 3. The polyurethane resin-forming composition according to claim 2, wherein the urethane group concentration of the resin obtained by curing the polyurethane resin-forming composition is 2000 mmol / kg or more and 4500 mmol / kg or less.

11. The polyurethane resin-forming composition according to claim 2, wherein the total content of the crosslinkable group in the crosslinking component (a-3) and the content of the crosslinkable group in the crosslinking component (b-3) is 25 mmol / kg or more and 1000 mmol / kg or less in the polyurethane resin-forming composition.

12. the polyurethane resin-forming composition is cured to obtain a resin having a urethane group concentration of 2000 mmol / kg or more and 4500 mmol / kg or less; The polyurethane resin-forming composition according to claim 2, wherein the total content of the crosslinkable group in the crosslinking component (a-3) and the content of the crosslinkable group in the crosslinking component (b-3) is 25 mmol / kg or more and 1000 mmol / kg or less in the polyurethane resin-forming composition.

13. The polyurethane resin-forming composition according to claim 2, wherein the content of the amino alcohol (a-2) in the polyurethane resin-forming composition is 40 mmol / kg or more and 600 mmol / kg or less.

14. the polyurethane resin-forming composition is cured to obtain a resin having a urethane group concentration of 2000 mmol / kg or more and 4500 mmol / kg or less; The polyurethane resin-forming composition according to claim 2, wherein the content of the amino alcohol (a-2) in the polyurethane resin-forming composition is 40 mmol / kg or more and 600 mmol / kg or less.

15. the total content of the crosslinkable group contained in the crosslinking component (a-3) and the content of the crosslinkable group contained in the crosslinking component (b-3) is 25 mmol / kg or more and 1000 mmol / kg or less in the polyurethane resin-forming composition, The polyurethane resin-forming composition according to claim 2, wherein the content of the amino alcohol (a-2) in the polyurethane resin-forming composition is 40 mmol / kg or more and 600 mmol / kg or less.

16. the polyurethane resin-forming composition is cured to obtain a resin having a urethane group concentration of 2000 mmol / kg or more and 4500 mmol / kg or less; the total content of the crosslinkable group contained in the crosslinking component (a-3) and the content of the crosslinkable group contained in the crosslinking component (b-3) is 25 mmol / kg or more and 1000 mmol / kg or less in the polyurethane resin-forming composition, The polyurethane resin-forming composition according to claim 2, wherein the content of the amino alcohol (a-2) in the polyurethane resin-forming composition is 40 mmol / kg or more and 600 mmol / kg or less.

17. The polyurethane resin-forming composition according to any one of claims 1 to 16, further comprising a filler (C).

18. The polyurethane resin-forming composition according to any one of claims 1 to 16, wherein at least one of the curing agent (A) and the isocyanate group-terminated prepolymer (B) is liquid at 25°C and 1 atmospheric pressure.

19. The polyurethane resin-forming composition according to any one of claims 1 to 16, wherein the curing agent (A) and the isocyanate group-terminated prepolymer (B) are both liquid at 25°C and 1 atmospheric pressure.

20. A urethane adhesive composition comprising the polyurethane resin-forming composition according to any one of claims 1 to 16.

21. The urethane resin adhesive composition according to claim 20, having a solvent content of 1.0 mass % or less.

22. A cured product of the urethane adhesive composition according to claim 20.

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