Polyurethane adhesive composition, cured product and adhesive

Abstract

To provide a composition for a polyurethane adhesive which exhibits a high adhesive strength in a wide temperature range, suppresses interface breakage when broken, and contributes to formation of an adhesive part exhibiting high coagulation breakage, a cured product, and an adhesive article.SOLUTION: A composition contains a curing agent (A) containing diol (a-1) and a crosslinking component (a-2), and an isocyanate group-terminated prepolymer (B) that is a reaction product of polyol (b-1) having an Mn of 2,500 or more and polyisocyanate (b-2), in which the diol (a-1) has an Mn in a specific range and is one or more selected from straight chain or branched aliphatic diol, a content of the polyol (b-1) is within a specific range, a content of a crosslinking group of the crosslinking component (a-2) is within a specific range, and urethane group concentration, OH group concentration and NCO group concentration in a polyurethane resin formative composition are within specific ranges.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present disclosure relates to polyurethane adhesive compositions, cured products, and bonded products. [Background technology]

[0002] Known adhesives include epoxy adhesives and urethane adhesives. However, epoxy adhesives have low flexibility and are therefore unable to adequately relieve thermal stress caused by temperature changes. Therefore, it is difficult to use epoxy adhesives in applications where large thermal stress occurs. On the other hand, urethane adhesives are highly flexible and can easily relieve thermal stress, so they are expected to be used in a variety of applications.

[0003] Patent Document 1 discloses a urethane adhesive composition comprising a first liquid containing a prepolymer obtained by reacting a polyisocyanate with a polyol of a specific number-average molecular weight, and a specific amount of catalyst, and a second liquid containing two specific polyols of number-average molecular weights and a catalyst, wherein the ratio of the molar numbers of hydroxyl groups derived from the polyols is within a specific range. According to Patent Document 1, this urethane adhesive composition not only provides good adhesive performance without pretreatment, but also has excellent storage stability for the first liquid containing an isocyanate component. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] International Publication No. 2009 / 047962 Summary of the Invention [Problem to be solved by the invention]

[0005] The urethane adhesive disclosed in Patent Document 1 can exhibit excellent adhesive strength at 25°C. However, to further expand its applications, urethane adhesives are required to exhibit high adhesive strength over a wider temperature range, and further improvements are needed. Furthermore, in the field of adhesives other than one-component adhesives, such as two-component system adhesives, there is a need to suppress variations in adhesive strength due to molding conditions such as the mixing / mixing time of multiple components. Therefore, one embodiment of the present disclosure is directed to providing a polyurethane adhesive composition that exhibits high adhesive strength over a wide temperature range and in which variation in adhesive strength due to molding conditions is suppressed. Another embodiment of the present disclosure is directed to providing a cured product of the polyurethane adhesive composition and an adhered article comprising the cured product. [Means for solving the problem]

[0006] A polyurethane adhesive composition according to one embodiment of the present disclosure comprises: a polyurethane resin-forming composition; A polyurethane adhesive composition comprising: The polyurethane resin-forming composition is a curing agent (A); an isocyanate group-terminated prepolymer (B); The curing agent (A) is Straight-chain aliphatic compounds with a number average molecular weight of 190 or less Diol (a-1), The polyol has an average functionality of 3 or more a cross-linking component (a-2); Number average molecular weight is 500 or more but less than 1000 Diol and a polyol (a-3) which is The isocyanate group-terminated prepolymer (B) is a polyol (b-1) having a number average molecular weight of 2500 or more; and polyisocyanate (b-2), the diol (a-1) is at least one selected from linear or branched aliphatic diols having a number average molecular weight of 190 or less; the content of the diol (a-1) in the polyurethane resin-forming composition is 400 mmol / kg or more and 2500 mmol / kg or less, the content of the polyol (a-3) is 0.9 mol % or more and 3 mol % or less relative to the diol (a-1), the content of the polyol (b-1) in the polyurethane resin-forming composition is 10 mmol / kg or more and 100 mmol / kg or less, the content of the polyisocyanate (b-2) in the polyurethane resin-forming composition is 1500 mmol / kg or more and 3500 mmol / kg or less; the content of the crosslinkable group contained in the crosslinking component (a-2) is 80 mmol / kg or more and 600 mmol / kg or less in the polyurethane resin-forming composition, The total content M of OH groups and urethane groups in the polyurethane resin-forming composition OH the total content M of NCO groups and urethane groups in the polyurethane resin-forming composition relative to [mol] NCO Ratio of [mol] R NCO / OH is between 0.8 and 2.0, In the polyurethane resin-forming composition , already formed Urethane group of concentration and the concentration of urethane groups formed by reaction of isocyanate groups and hydroxyl groups contained in the polyurethane adhesive composition. is between 2000mmol / kg and 5000mmol / kg.

[0007] A cured product according to another embodiment of the present disclosure is obtained by curing the polyurethane adhesive composition. An adhesive article according to still another embodiment of the present disclosure includes: a first adherend; and a second adherend; and The cured product, The first adherend portion and the second adherend portion are adhered together via the cured product. [Effects of the Invention]

[0008] According to one embodiment of the present disclosure, it is possible to provide a polyurethane adhesive composition that exhibits high adhesive strength over a wide temperature range and in which variation in adhesive strength due to molding conditions is suppressed. Also, according to another embodiment of the present disclosure, it is possible to provide a cured product of the polyurethane adhesive composition and an adhered article including the cured product. DETAILED DESCRIPTION OF THE INVENTION

[0009] Exemplary embodiments for carrying out the present disclosure are described in detail below.

[0010] <First embodiment (polyurethane adhesive composition)> A polyurethane adhesive composition according to one embodiment of the present disclosure comprises: a polyurethane resin-forming composition; A polyurethane adhesive composition comprising: The polyurethane resin-forming composition is a curing agent (A); an isocyanate group-terminated prepolymer (B); The curing agent (A) is Straight-chain aliphatic compounds with a number average molecular weight of 190 or less Diol (a-1), The polyol has an average functionality of 3 or more a cross-linking component (a-2); Number average molecular weight is 500 or more but less than 1000 Diol and a polyol (a-3) which is The isocyanate group-terminated prepolymer (B) is a polyol (b-1) having a number average molecular weight of 2500 or more; and polyisocyanate (b-2), the diol (a-1) is at least one selected from linear or branched aliphatic diols having a number average molecular weight of 190 or less; the content of the diol (a-1) in the polyurethane resin-forming composition is 400 mmol / kg or more and 2500 mmol / kg or less, the content of the polyol (a-3) is 0.9 mol % or more and 3 mol % or less relative to the diol (a-1), the content of the polyol (b-1) in the polyurethane resin-forming composition is 10 mmol / kg or more and 100 mmol / kg or less, the content of the polyisocyanate (b-2) in the polyurethane resin-forming composition is 1500 mmol / kg or more and 3500 mmol / kg or less; the content of the crosslinkable group contained in the crosslinking component (a-2) is 80 mmol / kg or more and 600 mmol / kg or less in the polyurethane resin-forming composition, The total content M of OH groups and urethane groups in the polyurethane resin-forming composition OH the total content M of NCO groups and urethane groups in the polyurethane resin-forming composition relative to [mol] NCO Ratio of [mol] R NCO / OH is between 0.8 and 2.0, In the polyurethane resin-forming composition , already formed Urethane group of concentration and the concentration of urethane groups formed by reaction of isocyanate groups and hydroxyl groups contained in the polyurethane adhesive composition. is between 2000mmol / kg and 5000mmol / kg.

[0011] [Polyurethane resin-forming composition] The polyurethane adhesive composition comprises a polyurethane resin-forming composition; and a filler (C). The polyurethane resin-forming composition comprises a curing agent (A); and an isocyanate group-terminated prepolymer (B).

[0012] [Hardening agent (A)] The curing agent (A) contains a diol (a-1), a crosslinking component (a-2), and a polyol (a-3) having a number average molecular weight of 500 or more and less than 1,000. The curing agent (A) may contain an active hydrogen-containing compound other than the diol (a-1), the crosslinking component (a-2) and the polyol (a-3).

[0013] [[Diol (a-1)]] The diol (a-1) is at least one selected from linear or branched aliphatic diols having a number average molecular weight of 190 or less. The aliphatic diol more preferably has a number average molecular weight of 150 or less. The diol (a-1) preferably contains a linear aliphatic diol having a number average molecular weight of 190 or less, and more preferably contains a linear aliphatic diol having a number average molecular weight of 150 or less.

[0014] The number average molecular weight in the present disclosure may be any molecular weight that can be measured with high accuracy, and for example, a molecular weight measured by a method (titration method) in accordance with JIS K 0070-1992 may be used.

[0015] 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.

[0016] The diol (a-1) may contain only one of these, or may contain two or more of them.

[0017] The content of diol (a-1) in the polyurethane resin-forming composition is preferably 400 mmol / kg or more and 2500 mmol / kg or more, more preferably 700 mmol / kg or more and 2000 mmol / kg or less, and even more preferably 1000 mmol / kg or more and 2000 mmol / kg or less.

[0018] [[Crosslinking component (a-2)]] Examples of the cross-linking component (a-2) include polyols having an average number of functional groups 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 compounds, monomer polyols of trimethylolpropane propylene oxide modified compounds, and pentaerythritol propylene oxide modified compounds. Other examples include polycaprolactone polyols obtained by ring-opening addition of cyclic esters such as ε-caprolactone, β-butyrolactone, γ-butyrolactone, γ-valerolactone, and δ-valerolactone to a polyol such as glycerin, trimethylolpropane, or pentaerythritol as an initiator.

[0019] The crosslinking component (a-2) may contain only one of these, or may contain two or more of them.

[0020] The content of the crosslinkable group in the crosslinking component (a-2) in the polyurethane resin-forming composition is preferably 80 mmol / kg or more and 600 mmol / kg or more, and more preferably 100 mmol / kg or more and 400 mmol / kg or less.

[0021] Here, the crosslinkable group is a functional group that forms a crosslink. Therefore, taking a trifunctional polyol (for example, glycerin) as an example, 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 groups is synonymous with the content of the trifunctional polyol, since a trifunctional polyol has one crosslinkable group.

[0022] [[Polyol (a-3)]] Examples of the polyol (a-3) having a number average molecular weight of 500 or more and less than 1000 include polyols containing one or more bonds selected from the group consisting of ester bonds, ether bonds, and carbonate bonds. Among these, polyester polyols, polyether polyols, and polycarbonate polyols are preferred, with polyether polyols being more preferred.

[0023] 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 dephenolation reaction between one or more polyols such as diols, ethylene oxide or propylene oxide adducts of bisphenol A, bis(β-hydroxyethyl)benzene, and xylylene glycol and one or more dialkyl carbonates such as dimethyl carbonate and diethyl carbonate, alkylene carbonates such as ethylene carbonate and propylene carbonate, and carbonates such as diphenyl carbonate, dinaphthyl carbonate, dianthryl carbonate, diphenanthryl carbonate, and diindanyl carbonate.

[0024] 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, and 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 one or more of: 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, 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) also include polyester-amide polyols obtained by replacing a portion of these alcohols with low-molecular-weight polyamines or low-molecular-weight amino alcohols, such as hexamethylenediamine, isophoronediamine, or monoethanolamine.

[0025] 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 polyether polyols include polyether polyols obtained by addition polymerization of alkylene oxides such as ethylene oxide, propylene oxide, and butylene oxide 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, and xylylene glycol; or low-molecular-weight polyamines such as ethylene diamine, propylene diamine, toluene diamine, metaphenylenediamine, diphenylmethane diamine, and xylylene diamine. Examples of polyether polyols 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.

[0026] Among these, polyether polyols are particularly preferred.

[0027] The content of the polyol (a-3) in the polyurethane resin-forming composition is preferably 0.9 mol % or more and 3 mol % or less relative to the diol (a-1).

[0028] The aliphatic diol (a-3) may contain only one of these, or may contain two or more of them.

[0029] [[Aliphatic diol (a-4)]] The curing agent (A) preferably contains, in addition to the diol (a-1), the crosslinking component (a-2), and the polyol (a-3), an aliphatic diol (a-4) having a number average molecular weight of 200 or more and 450 or less. Examples of the aliphatic diol (a-4) include the same as those listed for (a-3). Among these, polyester polyols, polyether polyols, and polycarbonate polyols are preferred, with polyether polyols being more preferred. The aliphatic diol (a-4) may contain only one of these, or may contain two or more of them.

[0030] [Isocyanate-terminated prepolymer (B)] 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 component, diol (b-3) having a number average molecular weight of 250 or more and less than 1,000. That is, the isocyanate group-terminated prepolymer (B) is obtained by modifying a polyisocyanate (b-2) with a polyol (b-1) and, if necessary, a diol (b-3). The isocyanate group-terminated prepolymer (B) may contain additives such as a reaction inhibitor and an antioxidant, if necessary.

[0031] [[Polyol (b-1)]] Examples of polyols (b-1) having a number average molecular weight of 2500 or more include those similar to those of (a-3). The polyol (b-1) preferably contains one or more bonds selected from the group consisting of an ester bond, an ether bond, and a carbonate bond. Among them, polyether polyols are particularly preferred. The number average molecular weight of the polyol (b-1) is preferably 2,500 or more and 10,000 or less, more preferably 2,500 or more and 7,000 or less, and even more preferably 2,500 or more and 4,500 or less.

[0032] The content of polyol (b-1) in the polyurethane resin-forming composition is preferably 10 mmol / kg or more and 100 mmol / kg or less, and more preferably 30 mmol / kg or more and 90 mmol / kg or less.

[0033] [[Polyisocyanate (b-2)]] The polyisocyanate (b-2) is not limited in any way as long as it is an unmodified isocyanate such as an aliphatic isocyanate, an alicyclic isocyanate, an aromatic isocyanate, an araliphatic isocyanate, etc. Among these, polyisocyanates containing a cyclic structure, i.e., an alicyclic isocyanate, an aromatic isocyanate, and an araliphatic isocyanate, are preferred, and from the viewpoints of reactivity and viscosity, aromatic isocyanates are more preferred.

[0034] Aliphatic isocyanates Examples of aliphatic isocyanates include hexamethylene diisocyanate, tetramethylene 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, and 2,4,4-trimethylhexamethylene diisocyanate. Examples of the isocyanate include 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.

[0035] [[[Alicyclic isocyanate]]] Examples of alicyclic isocyanates include isophorone diisocyanate, cyclohexyl diisocyanate, bis(isocyanatomethyl)cyclohexane, dicyclohexylmethane diisocyanate, methylcyclohexane diisocyanate, dicyclohexyldimethylmethane diisocyanate, 2,2'-dimethyldicyclohexylmethane diisocyanate, bis(4-isocyanato-n-butylidene)pentaerythritol, hydrogenated dimer acid diisocyanate, 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-isocyanato 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 diisocyanates include 2-isocyanatomethyl-2-(3-isocyanatopropyl)-6-(2-isocyanatoethyl)-bicyclo-[2.2.1]-heptane, 2,5-bis(isocyanatomethyl)-bicyclo[2.2.1]-heptane, hydrogenated diphenylmethane diisocyanate, norbornane diisocyanate, hydrogenated tolylene diisocyanate, hydrogenated xylene diisocyanate, and hydrogenated tetramethylxylene diisocyanate.

[0036] [[[Aromatic isocyanates]]] Examples of aromatic isocyanates include 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, a 2,4-tolylene diisocyanate / 2,6-tolylene diisocyanate mixture, 2,2'-diphenylmethane diisocyanate, a 2,2'-diphenylmethane diisocyanate / 4,4'-diphenylmethane diisocyanate mixture, 2,4'-diphenylmethane diisocyanate, a 2,4'-diphenylmethane diisocyanate / 4,4'-diphenylmethane diisocyanate mixture, and a 2,2'-diphenylmethane diisocyanate / 2,4'-diphenylmethane diisocyanate / 4,4'-diphenylmethane diisocyanate mixture. Examples of the diisocyanate mixture include diphenyl diisocyanate mixtures, m-xylylene diisocyanate, p-xylylene diisocyanate, 4,4'-diphenyl ether 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.

[0037] Aromatic Aliphatic Isocyanates Examples of the araliphatic isocyanate include 1,3- or 1,4-xylylene diisocyanate or a mixture thereof, 1,3- or 1,4-bis(1-isocyanato-1-methylethyl)benzene or a mixture thereof, and ω,ω'-diisocyanato-1,4-diethylbenzene.

[0038] The content of the polyisocyanate (b-2) in the polyurethane resin-forming composition is preferably 1500 mmol / kg or more and 3500 mmol / kg or less, and more preferably 1800 mmol / kg or more and 3000 mmol / kg or less.

[0039] [[Properties of polyol (b-1) and polyisocyanate (b-2)]] It is preferable that at least one of the polyol (b-1) and the polyisocyanate (b-2) is a liquid under normal pressure at 25° C. For example, in structural adhesive applications, the isocyanate group-terminated prepolymer (B) is required to be a liquid from the viewpoint of handling when used at room temperature.

[0040] [[Diol(b-3)]] Examples of the optional diol (b-3) having a number average molecular weight of 250 or more and less than 1000 include those similar to (a-3).

[0041] Although the diol (b-3) is an optional component, it is preferable that the polyurethane resin-forming composition contains the diol (b-3). The content of the diol (b-3) in the polyurethane resin-forming composition is preferably 150 mmol / kg or less. More preferably, it is 10 mmol / kg or more and 150 mmol / kg or less. The inclusion of the diol (b-3) is preferable because it improves the liquidity.

[0042] Furthermore, the diol (b-3) is preferably a liquid under normal pressure and 25°C conditions.

[0043] [ratio a-1 / b-1 ] The ratio R of the content [mol] of diol (a-1) to the content [mol] of polyol (b-1) a-1 / b-1 is more preferably 5 or more, and particularly preferably 10 or more.

[0044] [Content M OH , content M NCO , ratio R NCO / OH ] The total content M of OH groups and urethane groups in the polyurethane resin-forming composition OH [mol], where M is the total content of NCO groups and urethane groups in the polyurethane resin-forming composition. NCO Ratio of [mol] R NCO / OH is preferably 0.8 or more and 2.0 or less, and more preferably 0.9 or more and 1.8 or less.

[0045] Here, in the polyurethane resin-forming composition, the NCO groups of the polyisocyanate (b-2) react with the polyol (b-1) and the like, so that some of them form urethane groups, and the rest exist as NCO groups of the isocyanate-terminated prepolymer (B). NCO [mol] means the content of NCO groups, including those that have already reacted with OH groups to form urethane groups. On the other hand, in the polyurethane resin-forming composition, the OH groups of the polyol (b-1) react with the polyisocyanate (b-2) or the like to form urethane groups. OH [mol] means the content of OH groups, including those that have already reacted with NCO groups to form urethane groups, in addition to the OH groups that the curing agent (A) has.

[0046] [ The sum of the concentration of urethane groups already formed and the concentration of urethane groups generated by reaction of isocyanate groups and hydroxyl groups contained in the polyurethane adhesive composition ( Urethane group concentration ) ] In the polyurethane resin-forming composition , already formed Urethane group of concentration and the concentration of urethane groups formed by reaction of isocyanate groups and hydroxyl groups contained in the polyurethane adhesive composition. is 2000 mmol / kg or more and 5000 mmol / kg or less, preferably 3000 mmol / kg or more and 5000 mmol / kg or less, and more preferably 3000 mmol / kg or more and 4500 mmol / k or less.

[0047] Filler Examples of the filler (C) include known fillers, such as inorganic fillers and organic fillers, among which inorganic fillers are preferred.

[0048] 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.

[0049] Examples of organic fillers include polyamide particles, acrylic particles, carbon nanotubes, starch, natural organic fibers, and synthetic fibers.

[0050] The content of the filler is preferably 10% by mass or more and 70% by mass or less, and more preferably 10% by mass or more and 50% by mass or less, relative to the total mass of the polyurethane adhesive 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, resulting in better adhesive strength and coatability.

[0051] [[Method for producing isocyanate-terminated prepolymer (B)]] There are no particular limitations on the method for producing the isocyanate group-terminated prepolymer (B), and any known and commonly used method can be applied. For example, after adding polyisocyanate (b-2) to a stirring vessel, polyol (b-1) is added and stirred while maintaining the temperature inside the vessel at 40 to 70° C. Subsequently, the urethane reaction is allowed to proceed for about 2 to 5 hours while maintaining the temperature inside the stirring vessel at 70 to 90° C., thereby obtaining an isocyanate group-terminated prepolymer (B).

[0052] [Properties of curing agent (A) and isocyanate-terminated prepolymer (B)] It is preferable that the curing agent (A) and the isocyanate group-terminated prepolymer (B) are liquids under normal pressure at 25° C. For example, in structural adhesive applications, the curing agent (A) and the isocyanate group-terminated prepolymer (B) are required to be liquids from the viewpoint of handling when used at room temperature.

[0053] [catalyst] A catalyst can be used to promote the reaction between the curing agent (A) and the isocyanate-terminated prepolymer (B). It is particularly preferable that the catalyst content in the polyurethane resin-forming composition is 0.05% by mass or less, since this further suppresses the decrease in the elastic modulus of the resin at high temperatures and provides better high-temperature adhesion. The catalyst includes an isocyanurate catalyst, a urethanization catalyst, etc., and specific examples are as follows.

[0054] [[Isocyanuration catalyst]] Examples of the isocyanurate catalyst include tertiary amines such as triethylamine, N-ethylpiperidine, N,N'-dimethylpiperazine, N-ethylmorpholine, Mannich bases of phenolic compounds, potassium acetate, etc. These isocyanurate catalysts can be used alone or in combination of two or more.

[0055] [[Urethanization catalyst]] The urethanization catalyst can be appropriately selected from known catalysts, and examples thereof include amine-based catalysts, imidazole-based catalysts, and metal catalysts.

[0056] Amine catalyst Examples of amine catalysts include triethylenediamine, 2-methyltriethylenediamine, N,N,N',N'-tetramethylethylenediamine, N,N,N',N'-tetramethylpropylenediamine, N,N,N',N",N"-pentamethyldiethylenetriamine, N,N,N',N",N"-pentamethyl-(3-aminopropyl)ethylenediamine, N,N,N',N",N"-pentamethyldipropylenetriamine, N,N,N',N",N"-tetramethylhexamethylenediamine, and bis(2-dimethylaminoethyl)ether.

[0057] [[[Imidazole catalyst]]] Examples of imidazole catalysts include 1-methylimidazole, 1,2-dimethylimidazole, 1-isobutyl-2-methylimidazole, and 1-dimethylaminopropylimidazole.

[0058] Metal catalysts Examples of the metal catalyst include organotin catalysts such as stannous diacetate, stannous dioctoate, stannous dioleate, stannous dilaurate, dibutyltin oxide, dibutyltin diacetate, dibutyltin dilaurate, dibutyltin dichloride, and dioctyltin dilaurate.

[0059] [Other additives] The polyurethane resin-forming composition may further contain additives such as a reaction inhibitor, an antioxidant, and an antifoaming agent, as needed.

[0060] The polyurethane adhesive composition may comprise a mixed liquid (B') obtained by previously mixing an isocyanate group-terminated prepolymer (B) and a filler (C), and a curing agent (A); or may comprise a mixed liquid (A') obtained by previously mixing a curing agent (A) and a filler (C), and an isocyanate group-terminated prepolymer (B).

[0061] The filler and the polyurethane resin-forming composition can be easily mixed using a three-roll mixer, a planetary mixer, a revolving agitator, etc. In this case, it is preferable to carry out the kneading in a nitrogen atmosphere to prevent the mixing of moisture from the outside air.

[0062] A polyurethane adhesive composition according to an embodiment of the present disclosure can be used as an adhesive for a variety of applications, including, for example, the automotive field, the display field, the recording medium field, the electronic materials field, the battery field, the optical component field, the construction field, the electronic equipment field, and the aviation field. In the automotive field, examples include structural parts, switches, headlamps, internal engine parts, electrical components, drive engines, brake oil tanks, and the like of automobiles. In the display field, liquid crystal displays, organic electroluminescence displays, light-emitting diode displays, etc. are mentioned. Examples of recording media include video discs, CDs, DVDs, MDs, pickup lenses, VCM magnets, spindle motors, hard disk peripherals, and Blu-ray discs. Examples of applications in the electronic materials field include electronic components, electric circuits, electric contacts, and semiconductor elements. More specific examples of these applications include sealing materials, die bonding agents, conductive adhesives, anisotropic conductive adhesives, and interlayer adhesives for multilayer substrates including build-up substrates. In the battery field, examples include lithium ion batteries, manganese batteries, alkaline batteries, nickel-based batteries, fuel cells, silicon-based solar cells, dye-sensitized solar cells, and organic solar cells. The optical component field includes optical switch peripherals in optical communication systems, optical fiber materials for optical connector peripherals, optical passive components, optical circuit components, and optoelectronic integrated circuit peripherals. Examples of the electronic device field include camera modules.

[0063] The polyurethane adhesive composition according to the first embodiment exhibits high adhesive strength over a wide temperature range from room temperature to high temperatures, and the variation in adhesive strength due to molding conditions is suppressed. The term "room temperature to high temperature" means 15°C or higher and 200°C or lower, particularly 20°C or higher and 190°C or lower, and a high cohesive failure rate means 40% or higher.

[0064] <Second embodiment (cured product)> The cured product according to one embodiment of the present disclosure is obtained by curing a polyurethane adhesive composition. The curing conditions, such as the curing time and curing temperature, of the polyurethane adhesive composition are not particularly limited.

[0065] <Third embodiment (adhesive material)> An adhesive article according to one embodiment of the present disclosure comprises: a first adherend; and a second adherend; and The above-mentioned cured product, The first adherend portion and the second adherend portion are adhered together via the cured product. Examples of adhesive materials include various structures in the fields of automobiles, displays, recording media, electronic materials, batteries, optical components, architecture, electronic equipment, and aviation.

[0066] Here, the first and second adherends may be part of an integrated member, or may be part of separate members. When the first and second adherends are part of an integrated member, for example, the integrated member can be bent or folded, allowing the first and second adherends to come into contact with each other via the polyurethane adhesive composition.

[0067] According to the above-described embodiments of the present disclosure, it is possible to provide a polyurethane adhesive composition that exhibits high adhesive strength over a wide temperature range and in which variation in adhesive strength due to molding conditions is suppressed, as well as a cured product of the polyurethane adhesive composition and an adhered article including the cured product. Furthermore, the polyurethane adhesive composition according to one embodiment of the present disclosure is capable of strongly bonding dissimilar materials with different linear expansion coefficients even in environments exposed to high temperatures, such as in an electrodeposition baking process for bonding automobile structures, and is also capable of achieving high adhesive strength even at room temperature. Furthermore, the polyurethane adhesive composition according to one embodiment of the present disclosure combines high heat resistance and high flexibility with rapid curing properties, which contributes to high productivity. [Example]

[0068] The present invention will be explained in more detail with reference to examples and comparative examples, but the present invention is not limited to these examples at all. In addition, in Tables 1 to 3, the "sum of the concentration of urethane groups already formed and the concentration of urethane groups generated by reaction of isocyanate groups and hydroxyl groups contained in the polyurethane adhesive composition" is simply referred to as the "urethane group concentration."

[0069] Diol (a-1) and crosslinking component (a-2) were 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, polyol (b-1) and polyisocyanate (b-2) were added to a 2 L stirring vessel filled with nitrogen and stirred according to the formulations shown in Tables 1 to 3. Thereafter, the temperature inside the stirring vessel was maintained at 70 to 80°C, and the urethane reaction was allowed to proceed for about 2 to 5 hours, thereby obtaining various isocyanate-terminated prepolymers (B).

[0071] [Evaluation method] A filler (C) was added to an isocyanate-terminated prepolymer (B) according to the formulation shown in Tables 1 to 3, and the mixture was mixed using a revolving mixer (product name: Kakuhunter, manufactured by Shashin Kagaku Co., Ltd.) to obtain a mixture. A curing agent (A) was mixed into the obtained mixture according to the formulation shown in Tables 1 to 3 using a stainless steel spatula until uniform, thereby preparing a polyurethane adhesive composition. The obtained polyurethane adhesive composition was uniformly applied to an aluminum plate (100 mm length x 25 mm width; A6061, Ti-Zr treated) to prepare an adhesion test piece in accordance with JIS K 6850:1999.

[0072] (1) Adhesive strength An adhesive was applied to the surfaces of two aluminum plates (100 mm long x 25 mm wide x 1 mm thick; A6061, Ti-Zr treated), and the aluminum plates were bonded together so that the overlapping area was 12.5 mm long x 25 mm wide. This was left at 25°C for 10 hours and then heated at 180°C for 30 minutes to prepare an adhesion test piece. Glass beads were used to adjust the thickness of the adhesive layer to 0.25 mm, and an adhesion test piece was obtained. The tensile shear strength of the adhesive joints of the adhesive test specimens prepared as described above was measured using a tensile tester (product name: Autocom Universal Testing Machine AC-10kN-C, manufactured by TSE Co., Ltd.). This measurement was performed in accordance with JIS K6850:1999, tensile shear adhesive strength of adhesives. The measurement conditions were a chuck distance of 111.5 mm and a test speed of 10 mm / min. The measurement was performed at three temperatures: 25°C, 90°C, and 180°C.

[0073] The results of the adhesive strength measurements were judged according to the following criteria. <180℃> A: 2.0 MPa or more B: 1.8 MPa or more and less than 2.0 MPa C: Less than 1.8 MPa <90℃> A:15MPa or more B: 9 MPa or more and less than 15 MPa C: Less than 9 MPa <25℃> A:20MPa or more B: 8 MPa or more and less than 20 MPa C: Less than 8 MPa

[0074] (2) Adhesion strength variation rate with mixing time The curing agent (A) and the isocyanate group-terminated prepolymer (B) were mixed, and then the mixture was stirred for a predetermined stirring time (30 seconds / 150 seconds) to prepare an adhesion test piece, and the adhesive strength of the resulting test piece was evaluated. The ratio (%) of the adhesive strength of the adhesive test piece with a post-mixing stirring time of 30 seconds to the adhesive strength of the adhesive test piece with a post-mixing stirring time of 150 seconds was calculated, and the decrease from 100% was taken as the mixing time variation rate (%) of adhesive strength.

[0075] The rate of change in adhesive strength with stirring time was judged according to the following criteria. A: Less than 20% B: 20% or more but less than 30% C: 30% or more

[0076] (3) Cohesive failure rate After the tensile shear test, the broken surface of the sample was visually observed, and the proportion of the broken area in the adhesive layer was measured.

[0077] The cohesive failure rate was determined according to the following criteria. <180℃> A: 70% or more C: 40% or more but less than 70% D: Less than 40%

[0078] The abbreviations of the raw materials shown in Tables 1 to 3 are as follows. [Raw materials] (1) Hardener (A) 1,4-BG: Butylene glycol (Mitsubishi Chemical Corporation) 1,4-butanediol, average molecular weight 90, f=2 "PTMG250": PTMG250 (manufactured by Mitsubishi Chemical Corporation), Polytetramethylene ether glycol, average molecular weight 210, f=2 "PTMG650": PTMG650 (manufactured by Mitsubishi Chemical Corporation), Polytetramethylene ether glycol, average molecular weight 650, f=2 "PTMG850": PTMG850 (manufactured by Mitsubishi Chemical Corporation), Polytetramethylene ether glycol, average molecular weight 850, f=2 "TMP": Trimethylolpropane (manufactured by Mitsubishi Gas Chemical Company, Inc.) Trimethylolpropane, average molecular weight 134, f=3

[0079] (2) Isocyanate-terminated prepolymer (B) "PTG-L3500": Amorphous polytetramethylene ether glycol (Hodogaya Chemical Co., Ltd.), Average molecular weight 3500, f=2 "PCD3000": Amorphous polycarbonate polyol N-968 (Tosoh Corporation), Average molecular weight 3000, f=2 "PES3000": Amorphous polyester polyol Kuraray Polyol P-3010 (Kuraray Co., Ltd.), Average molecular weight 3000, f=2 "MT": Millionate MT (monomeric MDI, manufactured by Tosoh Corporation) Average molecular weight 250, f=2 "PCD500": Kuraray Polyol C-590 (manufactured by Kuraray Co., Ltd.), Polycarbonate polyol, average molecular weight 500, f=2

[0080] (3) Filler (C) "Zeolite": Zeolum A-3 (manufactured by Tosoh Corporation) "Talc": Crown Talc R (manufactured by Matsumura Sangyo Co., Ltd.)

[0081] [Table 1]

[0082] [Table 2]

[0083] [Table 3]

Claims

1. a polyurethane resin-forming composition; A polyurethane adhesive composition comprising: The polyurethane resin-forming composition is a curing agent (A); an isocyanate group-terminated prepolymer (B); The curing agent (A) is a linear aliphatic diol (a-1) having a number average molecular weight of 190 or less; a crosslinking component (a-2) which is a polyol having an average functionality of 3 or more; and polyol (a-3) which is a diol having a number average molecular weight of 500 or more and less than 1,000, The isocyanate group-terminated prepolymer (B) is a polyol (b-1) having a number average molecular weight of 2,500 or more; and polyisocyanate (b-2), the content of the diol (a-1) in the polyurethane resin-forming composition is 400 mmol / kg or more and 2500 mmol / kg or less, the content of the polyol (a-3) is 0.9 mol % or more and 3 mol % or less relative to the diol (a-1), the content of the polyol (b-1) in the polyurethane resin-forming composition is 10 mmol / kg or more and 100 mmol / kg or less, the content of the polyisocyanate (b-2) in the polyurethane resin-forming composition is 1500 mmol / kg or more and 3500 mmol / kg or less, the content of the crosslinkable group contained in the crosslinking component (a-2) is 80 mmol / kg or more and 600 mmol / kg or less in the polyurethane resin-forming composition, The total content M of OH groups and urethane groups in the polyurethane resin-forming composition ＯＨ [mol], the total content M of NCO groups and urethane groups in the polyurethane resin-forming composition ＮＣＯ Ratio R [mol] ＮＣＯ／ＯＨ is 0.8 or more and 2.0 or less, a polyurethane adhesive composition, wherein the sum of the concentration of urethane groups already formed in the polyurethane resin-forming composition and the concentration of urethane groups generated by reaction of isocyanate groups and hydroxyl groups possessed by the polyurethane adhesive composition is 2000 mmol / kg or more and 5000 mmol / kg or less.

2. 2. The polyurethane adhesive composition according to claim 1, wherein the curing agent (A) further comprises an aliphatic diol (a-4) having a number average molecular weight of 200 or more and 450 or less.

3. The polyurethane adhesive composition according to claim 1 or 2, wherein the polyisocyanate (b-2) contains a cyclic structure.

4. The polyurethane adhesive composition according to any one of claims 1 to 3, wherein the polyol (b-1) contains one or more bonds selected from the group consisting of an ester bond, an ether bond, and a carbonate bond.

5. The polyurethane adhesive composition according to any one of claims 1 to 4, wherein the curing agent (A) and the isocyanate group-terminated prepolymer (B) are liquids in an environment of normal pressure and 25°C.

6. The polyurethane adhesive composition according to any one of claims 1 to 5, wherein at least one of the polyol (b-1) and the polyisocyanate (b-2) is liquid in an environment of normal pressure and 25°C.

7. The isocyanate group-terminated prepolymer (B) is The polyol (b-1), The polyisocyanate (b-2), and a diol (b-3) having a number average molecular weight of 250 or more but less than 1,000, The polyurethane adhesive composition according to any one of claims 1 to 6, wherein the content of the diol (b-3) in the polyurethane resin-forming composition is 150 mmol / kg or less.

8. The polyurethane adhesive composition according to claim 7, wherein the diol (b-3) is liquid under normal pressure at 25°C.

9. The polyurethane adhesive composition according to any one of claims 1 to 8, wherein a content of the filler (C) in the polyurethane adhesive composition is 10% by mass or more and 70% by mass or less.

10. A cured product obtained by curing the polyurethane adhesive composition according to any one of claims 1 to 9.

11. a first adherend; and a second adherend; and The cured product according to claim 10, An adhered article, in which the first adherend and the second adherend are adhered via the cured product.

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