Moisture-curable resin composition

Abstract

This moisture-curable resin composition contains a compound (A) having at least one isocyanate group at a terminal of the molecule and two or more polymerizable double bonds in the molecule.

Description

Moisture-curable resin composition

[0001] The present invention relates to a moisture-curable resin composition, and more particularly to a moisture-curable resin composition used in electronic devices such as liquid crystal display devices.

[0002] Currently, the number of LCD display devices manufactured is increasing year by year, and improvements in productivity are required. Particular importance is attached to improving efficiency in the manufacturing process of fixing components. Conventionally, adhesives such as adhesive tape have been used to fix components in LCD display devices, but this process is largely manual, resulting in low yields and slow speed. Therefore, adhesives that can be applied automatically by machine are being considered as an alternative to tape.

[0003] For example, Patent Document 1 discloses a method for manufacturing a laminate that is applied to the manufacturing process of electronic devices such as mobile electronic device terminals, in-vehicle image displays, etc. In this manufacturing method, a moisture-curable polyurethane hot-melt resin composition is used as the adhesive, in which hydroxyethyl acrylate is blended as a photo-curable component into a polyurethane hot-melt adhesive.

[0004] Japanese Patent Application Laid-Open No. 2021-195375

[0005] When adhesives are used as a replacement for tape, if the load applied immediately after bonding the components is high, the uncured adhesive cannot withstand the force and the components slip off, or even if the components do not slip off, the adhesive may deform, causing problems such as misalignment of the bonded positions between the components, resulting in insufficient adhesion. Also, adhesives used to bond components generally tend to lose adhesion in high-temperature environments and may also be insufficiently reliable.

[0006] The composition disclosed in Patent Document 1 demonstrates that photocuring can achieve both fixation performance and adhesive strength immediately after lamination. However, Patent Document 1 does not disclose a composition that does not contain hydroxyethyl acrylate in the comparative examples, and the effect of this component in improving initial adhesive strength is unclear. The effect of incorporating hydroxyethyl acrylate, a monomer component, is considered to be limited. Furthermore, the effect of initial adhesive strength is generally considered to be due to the crystalline solidification that polyurethane hot melts typically exhibit. Furthermore, there is no mention of the amount of deformation of the adhesive under load or its adhesive properties in high-temperature environments. Therefore, there is a need for further improvements in the adhesive properties and reliability of adhesives used to bond components in devices such as liquid crystal displays.

[0007] Therefore, an object of the present invention is to provide a moisture-curable resin composition that can suppress component slippage and initial deformation under high load immediately after component lamination, and that has excellent adhesive properties and reliability.

[0008] As a result of extensive research, the inventors have found that the above-mentioned problems can be solved by adding a compound having at least one isocyanate group at a molecular terminal and two or more polymerizable double bonds in a moisture-curable resin composition, and have completed the present invention as described below. The present invention provides the following [1] to

[12] . [1] A moisture-curable resin composition containing a compound (A) having at least one isocyanate group at a molecular terminal and two or more polymerizable double bonds in the molecule. [2] The moisture-curable resin composition according to [1] above, wherein the compound (A) is a compound having a polymerizable double bond at the terminal of a side chain, further containing, in addition to the compound (A), a polymerizable compound (C) not containing an isocyanate group and a photopolymerization initiator. [3] The moisture-curable resin composition according to [1] or [2] above, wherein the compound (A) comprises a urethane resin (AU) that is a reaction product of a polyol (a1) and a polyfunctional isocyanate (a2), and the polyol (a1) comprises a polyol having a polymerizable double bond in the molecule. [4] The moisture-curable resin composition according to [3] above, wherein the polyol having a polymerizable double bond in the molecule comprises a polybutadiene polyol having a 1,2-bond in the molecule. [5] The moisture-curable resin composition according to [3] or [4] above, wherein the polyol (a1) further comprises a polyol having no polymerizable double bond in the molecule. [6] The moisture-curable resin composition according to any one of [1] to [5] above, further comprising, in addition to the compound (A), a compound (B) having an isocyanate group at a molecular terminal. [7] The moisture-curable resin composition according to [6] above, wherein the compound (B) comprises a compound (B1) having two or more isocyanate groups at the molecular terminal. [8] The moisture-curable resin composition according to any one of [2] to [7] above, wherein the polymerizable compound (C) comprises a compound (C1) having polymerizable double bonds at both ends of the main chain. [9] The moisture-curable resin composition according to [8] above, wherein the polymerizable compound (C) further comprises a monofunctional compound (C2) having one polymerizable double bond.

[10] The moisture-curable resin composition according to any one of [1] to [9] above, wherein the polymerizable double bond group ratio in the moisture-curable resin is 0.1 mass% or more and 1.5 mass% or less.

[11] The moisture-curable resin composition according to any one of [1] to

[10] above, having an isocyanate group content of 1 mass% or more.

[12] An adhesive for electronic devices, comprising the moisture-curable resin composition according to any one of [1] to

[11] above.

[0009] According to the present invention, it is possible to provide a moisture-curable resin composition that can suppress component slippage and initial deformation under high load immediately after component lamination, and that has excellent adhesive properties and reliability.

[0010] 1 is a schematic diagram showing an initial retention test. FIG. 2 is a schematic side view showing a method for measuring adhesive strength.

[0011] The present invention will be described in detail below with reference to embodiments. <Compound (A)> The moisture-curable resin composition of the present invention contains a compound (A) having at least one isocyanate group at the molecular end and two or more polymerizable double bonds in the molecule. The compound (A) contains a polymerizable double bond in the molecule, which makes it polymerizable by light irradiation or heating. Therefore, it immediately polymerizes upon light irradiation or the like, and even immediately after component lamination, it is possible to suppress initial deformation under high load and component slippage, thereby improving adhesion. Furthermore, by having at least one isocyanate group at the molecular end, compound (A) becomes a moisture-curable compound (moisture-curable resin). Therefore, the adhesive strength of the moisture-curable resin composition further improves after a certain period of time, and the moisture-curable resin composition can be imparted with a certain or higher final adhesive strength under room temperature and high temperature environments, thereby improving reliability.

[0012] The number of isocyanate groups in one molecule of compound (A) may be one or more, preferably two or more. By having an isocyanate group, compound (A) has moisture-curing properties and becomes a moisture-curing resin. Furthermore, having two or more isocyanate groups enhances moisture-curing properties and facilitates increasing the final adhesive strength. Compound (A) may contain both one and two or more isocyanate groups. The upper limit of the number of isocyanate groups in one molecule of compound (A) is not particularly limited, but may be, for example, five or less, or four or less. The isocyanate group may be located at the molecular terminal, but is preferably located at the terminal of the main chain. It is more preferable that the isocyanate group be located at at least both terminals of the main chain. In this specification, the main chain refers to the atomic chain with the largest number of atoms other than covalently bonded hydrogen atoms in compound (A), and the side chain refers to the atomic chain bonded to the main chain. The atomic chain referred to here may include a cyclic structure such as an aromatic ring.

[0013] The number of polymerizable double bonds in compound (A) may be plural, and is not particularly limited as long as it is two or more, and may be three or more, or four or more. The polymerizable double bond is a double bond that can be polymerized by light irradiation or heating, and is preferably a double bond at a molecular terminal. The polymerizable double bond in compound (A) may be either thermally polymerizable or photopolymerizable, but preferably has at least photopolymerizability. The group constituting the polymerizable double bond may be a vinyl group, a (meth)acryloyl group, etc., with a vinyl group being more preferred. Furthermore, the polymerizable double bond at the molecular terminal may be at the terminal of a side chain or at the terminal of a main chain, but is more preferably at the terminal of a side chain. Therefore, it is more preferred that compound (A) has a polymerizable double bond at the terminal of a side chain and an isocyanate group at the terminal of a main chain, and even more preferably has isocyanate groups at both terminals of the main chain. In this specification, the term "(meth)acryloyl group" means either an acryloyl group or a methacryloyl group, and the term "(meth)acrylic" means either an acrylic group or a methacrylic group, and the same applies to other similar terms.

[0014] The compound (A) may be any polymer having a repeating unit, and is preferably a urethane resin (AU) having a urethane bond. Hereinafter, the compound (A) will be described in detail using the example in which the compound (A) is a urethane resin (AU). The urethane resin (AU) is a reaction product of a polyol (a1) and a multifunctional isocyanate (a2). Specifically, the urethane resin (AU) can be obtained by reacting at least a polyol (a1) having two or more hydroxyl groups per molecule with a multifunctional isocyanate (a2) having two or more isocyanate groups per molecule. The isocyanate groups in the urethane resin (AU) may be residual isocyanate groups that did not react in the above reaction.

[0015] (Polyol (a1)) The polyol (a1) used as a raw material for the urethane resin (AU) is preferably a polyol having a polymerizable double bond in the molecule, preferably a polyol having a polymerizable double bond at the end of a side chain, and more preferably a polyol having a vinyl group at the end of a side chain. Specific examples of the polyol (a1) include polybutadiene polyol, epoxy (meth)acrylate, and compounds having a (meth)acryloyl group and two or more hydroxyl groups such as 2,3-dihydroxypropyl (meth)acrylate, and among these, polybutadiene polyol is preferred.

[0016] Polybutadiene polyol is a compound obtained by polymerizing butadiene and preferably has at least a 1,2-bond in the molecule, and typically has both a 1,2-bond and a 1,4-bond. By having a 1,2-bond in the molecule, polybutadiene polyol has a vinyl group at the end of the side chain. The vinyl group at the end of the side chain becomes a polymerizable double bond. Meanwhile, the double bond in the 1,4-bond is in the chain and does not constitute a polymerizable double bond. Polybutadiene polyol has at least two hydroxyl groups. Polybutadiene polyol typically has a hydroxyl group at the end of the main chain, and preferably has hydroxyl groups at both ends of the main chain.

[0017] The number average molecular weight (Mn) of the polyol having a polymerizable double bond in the molecule is preferably 500 or more and 30,000 or less, more preferably 1,000 or more and 5,000 or less, and even more preferably 1,500 or more and 3,500 or less.

[0018] As the polyol (a1), only a polyol having a polymerizable double bond in the molecule may be used, but in addition to a polyol having a polymerizable double bond in the molecule, a polyol not having a polymerizable double bond in the molecule may also be used. That is, the urethane resin (AU) may be a reaction product of a polyol (a1) consisting of a polyol having a polymerizable double bond in the molecule and a polyfunctional isocyanate (a2), or a reaction product of a polyol (a1) consisting of a polyol having a polymerizable double bond in the molecule and a polyol not having a polymerizable double bond in the molecule and a polyfunctional isocyanate (a2). Therefore, the urethane resin (AU) may have both a structure derived from a polyol having a polymerizable double bond and a structure derived from a polyol not having a polymerizable double bond in the molecule in one molecule. Note that, as the polyol not having a polymerizable double bond in the molecule, those exemplified as the polyol (b1) described below can be used. As the polyol not having a polymerizable double bond in the molecule, a polycarbonate polyol is preferred. Details of the polycarbonate polyol will be described later. The use of polycarbonate polyol facilitates improving adhesive strength. The number average molecular weight (Mn) of the polyol (a1) is preferably 1,000 or more and 5,000 or less, more preferably 1,200 or more and 4,000 or less, and even more preferably 1,500 or more and 3,500 or less. When there are multiple types of polyols (a1), the number average molecular weight (Mn) of the polyol (a1) referred to here is the number average molecular weight (Mn) of a mixture of the multiple types of polyols.

[0019] (Polyfunctional Isocyanate (a2)) As the polyfunctional isocyanate (a2), either an aromatic polyisocyanate compound or an aliphatic polyisocyanate compound is suitably used. Examples of the aromatic polyisocyanate compound include compounds in which an isocyanate group is bonded to an aromatic ring, such as diphenylmethane diisocyanate, a liquid modified product of diphenylmethane diisocyanate, polymeric MDI, tolylene diisocyanate, and naphthalene-1,5-diisocyanate. Examples of aliphatic polyisocyanate compounds include compounds in which an isocyanate group is bonded to a carbon atom constituting an aliphatic hydrocarbon, such as hexamethylene diisocyanate, trimethylhexamethylene diisocyanate, lysine diisocyanate, norbornane diisocyanate, transcyclohexane-1,4-diisocyanate, isophorone diisocyanate, hydrogenated xylylene diisocyanate, xylylene diisocyanate, hydrogenated diphenylmethane diisocyanate, cyclohexane diisocyanate, bis(isocyanatomethyl)cyclohexane, and dicyclohexylmethane diisocyanate. Among these, aromatic polyisocyanate compounds are preferred as the polyfunctional isocyanate (a2), from the viewpoints of increasing the moisture curing rate and increasing the adhesive strength after curing, and diphenylmethane diisocyanate is more preferred. The polyfunctional isocyanate (a2) may be used alone or in combination of two or more.

[0020] The reaction of polyol (a1) with polyfunctional isocyanate (a2) to obtain urethane resin (AU) is usually carried out in a molar ratio of hydroxyl groups (OH) in polyol (a1) to isocyanate groups (NCO) in polyfunctional isocyanate (a2) [NCO] / [OH] = 1.5 to 2.8, preferably 1.6 to 2.6. By having [NCO] / [OH] below the above upper limit, compound (A) can introduce isocyanate groups into compound (A) without using an excessive amount of polyfunctional isocyanate (a2). Also, by having it above the above lower limit, it becomes easier to introduce multiple isocyanate groups into compound (A) to improve moisture curing properties.

[0021] When a polyol having a polymerizable double bond in the molecule is used alone as the polyol (a1), the molar ratio ([NCO] / [OH]) is preferably 1.9 to 2.8, and more preferably 2.0 to 2.6. When the molar ratio ([NCO] / [OH]) is relatively high as described above, it becomes easier to introduce multiple isocyanate groups into the molecule, and for example, it becomes easier to incorporate isocyanate groups at both ends of the main chain.

[0022] Furthermore, when a polyol having a polymerizable double bond in the molecule and a polyol having no polymerizable double bond in the molecule are used in combination as the polyol (a1), the molar ratio ([NCO] / [OH]) is preferably 1.5 to 2.0, more preferably 1.6 to 1.9. By setting the molar ratio ([NCO] / [OH]) within the above range, it becomes easier to introduce multiple isocyanate groups into the molecule while lengthening the molecular chain of the resulting urethane resin (AU). Note that lengthening the molecular chain makes it easier to introduce both a structure derived from a polyol having a polymerizable double bond in the molecule and a structure derived from a polyol having no polymerizable double bond in the molecule into a single molecule. The urethane resin (AU) may be used alone or in combination of two or more types.

[0023] The weight average molecular weight of compound (A) is not particularly limited, but is preferably 1,000 to 50,000, more preferably 3,000 to 40,000, and even more preferably 4,000 to 30,000. When the weight average molecular weight is equal to or greater than the lower limit, for example, after initial curing, the composition has a certain level of hardness and is more likely to have excellent shape retention. Furthermore, when the weight average molecular weight is equal to or less than the upper limit, the moisture-curable resin composition tends to have appropriate fluidity, for example, even at room temperature (e.g., 25 ° C.), before curing, and has good coatability. Furthermore, when the weight average molecular weight is within the above range, adhesive strength and the like are also easily improved. In this specification, the number average molecular weight and weight average molecular weight are values ​​measured by gel permeation chromatography (GPC) and calculated in terms of polystyrene.

[0024] The content of compound (A) in the moisture-curable resin composition can be adjusted appropriately according to the number of polymerizable double bonds and the number of isocyanate groups contained in compound (A) so that the polymerizable double bond group ratio and isocyanate group content described below can be adjusted within the desired range. The content of compound (A) in the moisture-curable resin composition is not particularly limited, but is preferably 1 part by mass or more, more preferably 1.5 parts by mass or more, and even more preferably 2 parts by mass or more, per 100 parts by mass of the moisture-curable resin composition. When the content is above the above lower limit, compound (A) is appropriately polymerized by photocuring or thermal curing, making it easier to suppress initial deformation under high load immediately after component lamination. The content of compound (A) is preferably 70 parts by mass or less, more preferably 65 parts by mass or less, and even more preferably 60 parts by mass or less, per 100 parts by mass of the moisture-curable resin composition.

[0025] When a polyol having no polymerizable double bond in the molecule is used in combination with the compound (A) as described above, the content of the compound (A) may be relatively large and is not particularly limited, for example, 10 parts by mass to 70 parts by mass, more preferably 20 parts by mass to 65 parts by mass, and even more preferably 30 parts by mass to 60 parts by mass. When a polyol having a polymerizable double bond in the molecule is used alone as the polyol (A), the content of the compound (A) may be relatively small and is not particularly limited, but is preferably 1 part by mass to 10 parts by mass, more preferably 1.5 parts by mass to 8 parts by mass, and even more preferably 2 parts by mass to 6 parts by mass.

[0026] <Compound (B)> In the present invention, in addition to the above-mentioned compound (A), it is preferable to contain a compound (B) having an isocyanate group at the end of the molecule. Compound (B) is a compound other than compound (A), and does not have a polymerizable double bond in the molecule, or has a polymerizable double bond but the number of polymerizable double bonds in one molecule is one compound. Compound (B) is preferably a compound that does not have a polymerizable double bond in the molecule. Compound (B) becomes a compound having moisture curing properties (moisture curing resin) by having an isocyanate group at the end of the molecule. Therefore, by containing compound (B) in addition to compound (A), it is easier to further increase the final adhesive strength and reliability.

[0027] Compound (B) is preferably a compound (B1) having two or more isocyanate groups at the molecular terminals, more preferably a compound having isocyanate groups at both terminals of the main chain, and even more preferably a compound having two isocyanate groups. When compound (B) has two or more isocyanate groups at the molecular terminals, particularly when compound (B) has isocyanate groups at both terminals of the main chain, moisture curing properties are enhanced, and final adhesive strength and reliability are more likely to be improved.

[0028] The compound (B) may be any polymer having a repeating unit, and is preferably a urethane resin (BU) (urethane prepolymer) having a urethane bond. Hereinafter, the compound (B) will be described in detail using an example in which the compound (B) is a urethane resin. The urethane resin (BU) is a reaction product of a polyol (b1) and a polyfunctional isocyanate (b2). Specifically, the urethane resin (BU) can be obtained by reacting a polyol (b1) having at least two hydroxyl groups per molecule with a polyfunctional isocyanate (b2) having two or more isocyanate groups per molecule. The isocyanate groups in the urethane resin (BU) may be residual isocyanate groups that did not react in the above reaction. The urethane resin (BU) is preferably a compound (B1) having two or more isocyanate groups at the molecular terminals, more preferably a compound having isocyanate groups at both terminals of the main chain, and even more preferably having two isocyanate groups.

[0029] (Polyol (b1)) The polyol (b1) used as a raw material for the urethane resin (BU) is preferably a polyol having no polymerizable double bonds in the molecule. Specific examples of the polyol (b1) include polyol compounds having at least one of a polyester skeleton, a polyether skeleton, and a polycarbonate skeleton, and among these, polyol compounds having a polycarbonate skeleton are preferred. The polyol (b1) may also have two or more skeletons selected from the group consisting of a polyester skeleton, a polyether skeleton, and a polycarbonate skeleton.

[0030] Here, the polyol compound having a polyester skeleton is preferably a polyester polyol. Specific examples include polyester polyols obtained by reacting a polycarboxylic acid with a polyol, and poly-ε-caprolactone polyols obtained by ring-opening polymerization of ε-caprolactone. The polyester polyol is preferably a polyester diol. Examples of the polycarboxylic acids used as raw materials for polyester polyols include phthalic acid, terephthalic acid, isophthalic acid, 1,5-naphthalic acid, 2,6-naphthalic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, decamethylene dicarboxylic acid, and dodecamethylene dicarboxylic acid. Among these, phthalic acid, terephthalic acid, isophthalic acid, and adipic acid are preferred from the viewpoint of easily increasing adhesive strength at high temperatures. These polycarboxylic acids may be used alone or in combination of two or more. Examples of the polyols that can be used as raw materials for polyester polyols include ethylene glycol, propylene glycol, 1,3-propanediol, 1,4-butanediol, neopentyl glycol, 1,5-pentanediol, 1,6-hexanediol, diethylene glycol, and cyclohexanediol. Among these, 1,6-hexanediol or 1,4-butanediol is preferred from the viewpoint of easier enhancement of adhesive strength at high temperatures. These polyols may be used alone or in combination of two or more.

[0031] Examples of polyol compounds having a polyether skeleton include polyether polyols. Polyether polyols are preferably polyether diols. Examples of polyether polyols include polyalkylene glycols such as polyethylene glycol, polypropylene glycol, ring-opening polymers of tetrahydrofuran, and ring-opening polymers of 3-methyltetrahydrofuran, as well as random or block copolymers of these or their derivatives, and bisphenol-type polyoxyalkylene modified products. Here, the bisphenol-type polyoxyalkylene modified product is a polyether polyol obtained by addition reaction of an alkylene oxide (e.g., ethylene oxide, propylene oxide, butylene oxide, isobutylene oxide, etc.) with the active hydrogen moiety of a bisphenol-type molecular skeleton. The polyether polyol may be a random copolymer or a block copolymer. The bisphenol-type polyoxyalkylene modified product preferably has one or more alkylene oxides attached to both ends of the bisphenol-type molecular skeleton. The bisphenol-type is not particularly limited, and examples include A-type, F-type, and S-type, with bisphenol A-type being preferred.

[0032] Examples of polyol compounds having a polycarbonate skeleton include polycarbonate polyols. Polycarbonate polyols have a structure in which structural units derived from polyhydroxy compounds are linked by carbonate bonds. There are no particular limitations on the method for producing polycarbonate polyols, and they may be produced using a polyhydroxy compound as a raw material by a known method such as a phosgene method or an ester exchange method.

[0033] The polyhydroxy compound is generally a dihydroxy compound. The polyhydroxy compound may be any of an aliphatic polyol, an alicyclic polyol having an alicyclic structure, an aromatic polyhydroxy compound, etc., but the polyhydroxy compound is preferably an aliphatic polyol or an alicyclic polyol, and more preferably an aliphatic polyol. The aliphatic polyol is a divalent linear aliphatic polyol or a divalent branched aliphatic polyol. The aliphatic polyol may not have, for example, an ether bond. In such a case, examples of the aliphatic polyol include alkanediols having 2 to 16, and preferably about 4 to 12, carbon atoms. Specific examples include linear aliphatic polyols such as 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,7-heptanediol, 1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, 1,11-undecanediol, 1,12-dodecanediol, 1,13-tridecanediol, 1,14-tetradecanediol, 1,15-pentadecanediol, and 1,16-hexadecanediol; and branched aliphatic polyols such as neopentyl glycol and 3-methyl-1,5-pentanediol. Among these, 1,6-hexanediol, 1,7-heptanediol, 1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, 1,11-undecanediol, 1,12-dodecanediol, and 3-methyl-1,5-pentanediol are preferred, and 1,6-hexanediol and 3-methyl-1,5-pentanediol are more preferred. The above aliphatic polyols may be used alone or in combination of two or more.

[0034] The polycarbonate polyol may be a polyether polycarbonate polyol having a polyether skeleton. Polyether polycarbonate polyols have ether bonds in structural units derived from a polyhydroxy compound, and a polyether polyol may be used as the polyhydroxy compound. Specific examples of polyether polyols include polyalkylene glycols. The polyalkylene glycols are alkylene groups having, for example, 2 to 8 carbon atoms, preferably 2 to 4 carbon atoms. Specific examples of polyalkylene glycols used as the polyhydroxy compound include polyethylene glycol, polypropylene glycol, polytetramethylene glycol, polyisobutylene glycol, etc., and may also be copolymers of two or more of ethylene glycol, propylene glycol, tetramethylene glycol, isobutylene glycol, and trimethylene glycol.

[0035] The polyol (b1) may be used singly or in combination of two or more. That is, the urethane resin (BU) may be a reaction product of two or more polyols (b1) and a polyfunctional isocyanate (b2). Therefore, by using two or more polyols (b1) having different skeletons, it is possible to introduce two types of skeletons from a polyester skeleton, a polyether skeleton, and a polycarbonate skeleton into one molecule.

[0036] Among the above polyols, polycarbonate polyols are preferred as polyol (b1) from the viewpoints of adhesive strength and reliability. The polycarbonate polyol preferably contains a polyether polycarbonate polyol. Use of a polyether polycarbonate polyol tends to increase the elastic modulus at high temperatures, making it easier to improve high-temperature adhesive strength and reliability. When a polyether polycarbonate polyol is used as the polycarbonate polyol, the polyether polycarbonate polyol may be used in combination with a polycarbonate polyol other than the polyether polycarbonate polyol.

[0037] As the polyfunctional isocyanate (b2) used in the polyurethane resin (BU), those listed as the polyfunctional isocyanate (a2) above can be used as appropriate, and among them, from the viewpoint of being able to increase the moisture curing rate and to increase the adhesive strength after curing, aromatic polyisocyanate compounds are preferred, and diphenylmethane diisocyanate is more preferred among them. The urethane resin (BU) may be used alone or in combination of two or more types.

[0038] The reaction between the polyol (b1) and the polyfunctional isocyanate (b2) when producing the urethane resin (BU) is carried out, for example, at a molar ratio of hydroxyl groups (OH) in the polyol (b1) to isocyanate groups (NCO) in the polyfunctional isocyanate (b2), [NCO] / [OH], in the range of 1.9 to 2.6, preferably 2.0 to 2.5. By carrying out the reaction within this range, it becomes easy to introduce multiple isocyanate groups into the molecule without increasing the molecular weight of the urethane resin (BU) more than necessary.

[0039] Furthermore, compounds other than the urethane resin (BU) may be used as the compound (B), for example, a urethane (meth)acrylate having an isocyanate group may be used. The urethane (meth)acrylate is also preferably a compound (B1) having two or more isocyanate groups at the molecular terminals, more preferably a compound having isocyanate groups at both terminals of the main chain, and even more preferably a compound having two isocyanate groups. Furthermore, the urethane (meth)acrylate may have one polymerizable double bond or one (meth)acryloyl group in the molecule.

[0040] The weight average molecular weight of compound (B) is not particularly limited, but is preferably 2000 to 50,000, more preferably 3000 to 40,000, and even more preferably 4000 to 30,000. When the weight average molecular weight is equal to or greater than the lower limit, for example, after initial curing, the composition has a certain level of hardness and is more likely to have excellent shape retention. Furthermore, when the weight average molecular weight is equal to or less than the upper limit, the moisture-curable resin composition is more likely to have appropriate moisture curing properties and increase the final adhesive strength. Furthermore, when the weight average molecular weight is equal to or less than the upper limit, the moisture-curable resin composition tends to have appropriate fluidity, for example, even at room temperature (e.g., 25 ° C.) before curing, and the coatability is improved.

[0041] The content of compound (B) in the moisture-curable resin composition is preferably 60 parts by mass or less, more preferably 55 parts by mass or less, and even more preferably 50 parts by mass or less, relative to 100 parts by mass of the moisture-curable resin composition. When the content of compound (B) is below the above upper limit, it becomes easier to make the content of compound (A) a certain level or more, and it becomes easier to suppress initial deformation under high load immediately after lamination of the component. In addition, compound (B) does not have to be contained in the moisture-curable resin composition, and the content of compound (B) may be 0 parts by mass or more, preferably 0.5 parts by mass or more, more preferably 1 part by mass or more, and even more preferably 10 parts by mass or more, relative to 100 parts by mass of the moisture-curable resin composition. By making the content of compound (B) a certain amount or more, it becomes easier to increase the moisture curability and increase the final adhesive strength.

[0042] Also, as described above, when a polyol having no polymerizable double bond in the molecule is used in combination as the polyol (a1) in the compound (A), the content of the compound (B) may be relatively small, for example, 0 parts by mass or more and 30 parts by mass or less, preferably 0.5 parts by mass or more and 20 parts by mass or less, more preferably 1 part by mass or more and 10 parts by mass or less, relative to 100 parts by mass of the moisture-curable resin composition. Also, when a polyol having a polymerizable double bond in the molecule is used alone as the polyol (a1) in the compound (A), the content of the compound (B) may be relatively large, preferably 10 parts by mass or more and 70 parts by mass or less, more preferably 25 parts by mass or more and 65 parts by mass or less, and even more preferably 35 parts by mass or more and 60 parts by mass or less, relative to 100 parts by mass of the moisture-curable resin composition.

[0043] The total amount of moisture-curing resin in the moisture-curing resin composition is preferably 20 to 80 parts by mass, more preferably 30 to 70 parts by mass, and even more preferably 40 to 65 parts by mass, per 100 parts by mass of the moisture-curing resin composition. When the total amount of moisture-curing resin is equal to or greater than the above lower limit, it is possible to impart appropriate moisture curing properties and increase the final adhesive strength. Furthermore, when it is equal to or less than the above upper limit, it is possible to contain a relatively large amount of components other than the moisture-curing resin, such as the compound (C) described below, in the moisture-curing resin composition. The moisture-curing resin in the moisture-curing resin composition is typically compound (A) and compound (B). Therefore, the content of the compound (A) and compound (B) (when compound (B) is not contained, the content of compound (A) alone) is preferably within the above range.

[0044] When the moisture-curing resin is a urethane resin, as described above, the polyols (polyol (a1) and polyol (b1)) used as raw materials for the urethane resin preferably contain both a polyol having a polymerizable double bond in the molecule and a polyol having no polymerizable double bond in the molecule. In addition, in the raw materials for the urethane resin contained in the moisture-curing resin, the content of the polyol having a polymerizable double bond in the molecule is preferably 2% by mass or more and 25% by mass or less, more preferably 3% by mass or more and 20% by mass or less, and even more preferably 4% by mass or more and 15% by mass or less, based on the total amount of polyols constituting the urethane resin, from the viewpoint of improving the final adhesive strength while making it easier to suppress initial deformation. As explained in the compound (A) and compound (B), the polyol (a1) and the polyol (b1) may both be introduced into the same molecule, or each may be introduced into a different molecule.

[0045] The polymerizable double bond group ratio in the moisture-curable resin contained in the moisture-curable resin composition is, for example, 0.1% by mass or more and 1.5% by mass or less. When the polymerizable double bond group ratio is 0.1% by mass or more, the resin is immediately polymerized by light irradiation or the like, and initial deformation under high load can be suppressed even immediately after lamination of the member. Furthermore, when the polymerizable double bond group ratio is 1.5% by mass or less, excessive curing at the initial stage is prevented, making it easier to improve the final adhesive strength. From the viewpoint of appropriately suppressing initial deformation, the polymerizable double bond group ratio is preferably 0.2% by mass or more, more preferably 0.3% by mass or more, and even more preferably 0.4% by mass or more. Furthermore, from the viewpoint of making it easier to improve the final adhesive strength, the polymerizable double bond group ratio is preferably 1.3% by mass or less, more preferably 1.0% by mass or less, and even more preferably 0.9% by mass or less.

[0046] The polymerizable double bond group ratio in a moisture-curing resin refers to the ratio of the mass of polymerizable double bond groups contained in the total mass of the moisture-curing resin. In this case, the mass ratio of polymerizable double bond groups in each moisture-curing resin can be calculated from the ratio of the molecular weight of the polymerizable double bond groups in one molecule to the molecular weight of the moisture-curing resin. The molecular weight of the moisture-curing resin referred to here is the calculated number average molecular weight of the moisture-curing resin. The calculated number average molecular weight can be determined by the following formula (i). The molecular weight of the polymerizable double bond group is the molecular weight of the carbon atoms constituting the double bond and the hydrogen atoms bonded to those carbon atoms, and is calculated based on ... 1,2-vinyl bond (-CH=CH ２ ), the ratio is 27, and if there are two 1,2-vinyl bonds in one molecule, the number of polymerizable double bond groups in one molecule is 54. If there are two or more types of moisture-curable resins, the polymerizable double bond group ratio for each compound may be determined in the same manner and calculated as a weighted average according to the content.

[0047]

[0048] The moisture-curable resin composition contains a certain amount of isocyanate groups by containing compound (A) or both compound (A) and compound (B) as described above. The isocyanate group (NCO) content in the moisture-curable resin composition is preferably 0.5% by mass or more, more preferably 1% by mass or more. An isocyanate group content of 0.5% by mass or more, especially 1% by mass or more, can impart sufficient moisture curing properties, making it easier to improve final adhesive strength and reliability. Furthermore, the isocyanate group content in the moisture-curable resin composition is preferably 2.5% by mass or less. An isocyanate group content of 2.5% by mass or less prevents excessive moisture curing, making it easier to improve initial adhesive strength and reliability. The isocyanate group content in the moisture-curable resin composition can be calculated based on the isocyanate group content contained in the moisture-curable resin. In this case, if there are two or more moisture-curable resins, the isocyanate group content for each compound may be determined in the same manner and calculated as a weighted average according to the content. The isocyanate group content in each moisture-curing resin can be determined, for example, by calculating the amount of residual isocyanate groups based on the amount of isocyanate and polyol added during synthesis, and then calculating the residual isocyanate groups and the calculated number average molecular weight of the moisture-curing resin. The calculated number average molecular weight can be determined using the above formula (i).

[0049] <Polymerizable Compound (C)> The moisture-curable resin composition of the present invention preferably further contains a polymerizable compound (C). The polymerizable compound (C) may have a polymerizable double bond. The polymerizable double bond of the polymerizable compound (C) may be either thermally polymerizable or photopolymerizable, but preferably has at least photopolymerizability. The polymerizable compound (C) is a compound other than the above compounds (A) and (B), does not contain an isocyanate group, etc., and does not have moisture curing properties. By further containing a polymerizable compound (C) in addition to compound (A), or compound (A) and compound (B), the moisture-curable resin composition of the present invention becomes more easily cured by light irradiation, etc., making it easier to increase the initial adhesive strength and reduce the initial deformation amount.

[0050] [Compound (C1)] The polymerizable compound (C) may be a polyfunctional polymerizable compound having two or more polymerizable double bonds. Among these, compound (C1) having polymerizable double bonds at both ends of the main chain is preferred. The use of compound (C1) having polymerizable double bonds at both ends of the main chain facilitates suppression of initial deformation. Furthermore, as described above, compound (A) having a terminal polymerizable double bond and the composition containing compound (C1) further facilitates suppression of initial deformation. Compound (C1) may be a polymer having a repeating unit. The weight-average molecular weight of compound (C1) is, for example, 1,000 to 200,000, preferably 3,000 to 150,000, and more preferably 5,000 to 120,000.

[0051] Compound (C1) is preferably a urethane (meth)acrylate. The urethane (meth)acrylate is a compound having at least a (meth)acryloyl group and a urethane bond. The urethane (meth)acrylate used as compound (C1) can be obtained, for example, by reacting a polyol compound with a polyisocyanate compound to obtain a terminal isocyanate group-containing urethane prepolymer, and then further reacting the resulting prepolymer with a hydroxyl group-containing (meth)acrylate.

[0052] The polyol used to obtain the urethane (meth)acrylate used as compound (C1) is not particularly limited, but examples thereof include ethylene glycol, propylene glycol, glycerin, sorbitol, trimethylolpropane, polycarbonate diol, polyether diol, polyester diol, polycaprolactone diol, etc. Furthermore, the polyvalent isocyanate compound is not particularly limited, but can be appropriately selected from the compounds listed as the polyfunctional isocyanate (a2) above and used. The hydroxyl group-containing (meth)acrylate is not particularly limited, as long as it is a compound having a hydroxy group and a (meth)acryloyl group in at least one molecule. Specific examples of (meth)acrylates having a hydroxy group include hydroxyacryl(meth)acrylates such as 2-hydroxyethyl(meth)acrylate, 2-hydroxypropyl(meth)acrylate, and 4-hydroxybutyl(meth)acrylate, hydroxycycloacryl(meth)acrylates such as 5-hydroxycyclooctyl(meth)acrylate and 4-hydroxycyclohexyl(meth)acrylate, and 2-hydroxy-3-phenyloxypropyl(meth)acrylate. Further examples include mono(meth)acrylates or di(meth)acrylates of trihydric alcohols such as trimethylolethane, trimethylolpropane, and glycerin, and epoxy(meth)acrylates such as bisphenol A-type epoxy(meth)acrylate.

[0053] The content of compound (C1) in the moisture-curable resin composition is preferably 0.5 parts by mass or more and 10 parts by mass or less relative to 100 parts by mass of the moisture-curable resin composition. By being 0.5 parts by mass or more, the effect of incorporating compound (C1) is easily exhibited. Furthermore, by being 10 parts by mass or less, it becomes easier to incorporate other components such as compound (A) and compound (B) in the desired amount, and various performances such as final adhesive strength are easily improved. The content of compound (C1) is more preferably 1.0 parts by mass or more and 5 parts by mass or less, and even more preferably 1.5 parts by mass or more and 3 parts by mass or less relative to 100 parts by mass of the moisture-curable resin composition.

[0054] [Compound (C2)] As the polymerizable compound (C), a monofunctional compound (C2) having one polymerizable double bond may be used. The use of compound (C2) in the moisture-curable resin composition facilitates improved initial adhesive strength. Furthermore, in the semi-cured state after initial curing and before moisture curing, the moisture-curable resin composition has a certain level of hardness or higher, making it easier to ensure excellent shape retention. With excellent shape retention, a moisture-curable resin composition applied, for example, with a dispenser, can ensure a certain height after photocuring, thereby ensuring a certain distance between adherends with a cured product formed from the moisture-curable resin composition. While either compound (C1) or (C2) described above may be used alone as the polymerizable compound (C), it is preferable to contain both compounds (C1) and (C2). Furthermore, the moisture-curable resin composition is more likely to have a reduced viscosity when containing compound (C2). Therefore, the moisture-curable resin composition can easily maintain appropriate fluidity at room temperature (e.g., 25°C) before curing, improving workability, such as coatability. The polymerizable double bond in the compound (C2) may be either a (meth)acryloyl group or a vinyl group, but from the viewpoint of enhancing photocurability, a vinyl group or an acryloyl group is preferred.

[0055] The type of compound (C2) is not particularly limited, but may be appropriately selected so that the glass transition temperature after polymerization falls within a certain range and the cured product has a certain level of viscoelasticity depending on the application, use environment, required performance, etc. Compound (C) is not particularly limited, but examples thereof include nitrogen-containing compounds, alkyl (meth)acrylates, (meth)acrylates having an alicyclic structure, (meth)acrylates having an aromatic ring, and (meth)acrylates containing a cyclic ether group, and other (meth)acrylic acid ester compounds other than nitrogen-containing compounds.

[0056] The nitrogen-containing compound may be a nitrogen-containing compound having a cyclic structure or a chain-like nitrogen-containing compound. The nitrogen-containing compound having a cyclic structure is one in which a nitrogen atom is contained in an atom constituting the ring itself, and examples thereof include nitrogen-containing compounds having a lactam structure such as N-vinylpyrrolidone and N-vinyl-ε-caprolactam, compounds containing a morpholine skeleton such as N-acryloylmorpholine, and cyclic imide compounds such as N-(meth)acryloyloxyethylhexahydrophthalimide. The chain nitrogen-containing compound is a compound in which the nitrogen atom does not constitute a ring itself, and examples thereof include chain amino group-containing (meth)acrylates such as dimethylamino(meth)acrylate, diethylamino(meth)acrylate, aminomethyl(meth)acrylate, aminoethyl(meth)acrylate, and dimethylaminoethyl(meth)acrylate; chain (meth)acrylamide compounds such as diacetone acrylamide, N,N-dimethylacrylamide, N,N-diethylacrylamide, N-isopropylacrylamide, N-hydroxyethylacrylamide, acrylamide, and methacrylamide; and N-vinylacetamide.

[0057] The chain-like nitrogen-containing compound may be a monofunctional urethane (meth)acrylate. For example, the monofunctional urethane (meth)acrylate may be a compound obtained by reacting an isocyanate compound with a (meth)acrylate having a hydroxyl group. The (meth)acrylate having a hydroxyl group is as described above. Examples of the isocyanate compound used to obtain the monofunctional urethane (meth)acrylate include alkane monoisocyanates such as butane isocyanate, hexane isocyanate, and decane isocyanate, and aliphatic monoisocyanates such as cycloaliphatic monoisocyanates such as cyclopentane isocyanate, cyclohexane isocyanate, and isophorone monoisocyanate. The nitrogen-containing compound is preferably a nitrogen-containing compound having a lactam structure or a nitrogen-containing compound having a cyclic structure such as a morpholine skeleton-containing compound.

[0058] Examples of the alkyl (meth)acrylate include alkyl (meth)acrylates having an alkyl group with about 1 to 18 carbon atoms, such as methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate, t-butyl (meth)acrylate, n-octyl (meth)acrylate, isooctyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, isononyl (meth)acrylate, isodecyl (meth)acrylate, lauryl (meth)acrylate, isomyristyl (meth)acrylate, and stearyl (meth)acrylate.

[0059] Examples of the (meth)acrylate having an alicyclic structure include cyclohexyl (meth)acrylate, 4-tert-butylcyclohexyl (meth)acrylate, 3,3,5-trimethylcyclohexyl (meth)acrylate, isobornyl (meth)acrylate, and dicyclopentenyl (meth)acrylate.

[0060] Examples of (meth)acrylates having an aromatic ring include phenylalkyl (meth)acrylates such as benzyl (meth)acrylate and 2-phenylethyl (meth)acrylate, and phenoxyalkyl (meth)acrylates such as phenoxyethyl (meth)acrylate. Furthermore, (meth)acrylates having multiple benzene rings, such as a fluorene skeleton or a biphenyl skeleton, may also be used, and specific examples include fluorene-type (meth)acrylates and ethoxylated o-phenylphenol acrylate. Further examples include phenoxypolyoxyethylene (meth)acrylates such as phenoxydiethylene glycol (meth)acrylate, phenoxypolyethylene glycol (meth)acrylate, nonylphenoxydiethylene glycol (meth)acrylate, and nonylphenoxypolyethylene glycol (meth)acrylate.

[0061] Examples of cyclic ether group-containing (meth)acrylates include (meth)acrylates having an epoxy ring, oxetane ring, tetrahydrofuran ring, dioxolane ring, dioxane ring, etc. Examples of epoxy ring-containing (meth)acrylates include glycidyl (meth)acrylate. Examples of oxetane ring-containing (meth)acrylates include (3-ethyloxetan-3-yl)methyl (meth)acrylate. Examples of tetrahydrofuran ring-containing (meth)acrylates include tetrahydrofurfuryl (meth)acrylate and (meth)acrylic acid polymer esters of tetrahydrofurfuryl alcohol. Examples of dioxolane ring-containing (meth)acrylates include (2-methyl-2-ethyl-1,3-dioxolan-4-yl)methyl (meth)acrylate and (2,2-cyclohexyl-1,3-dioxolan-4-yl)methyl (meth)acrylate. Examples of (meth)acrylates having a dioxane ring include cyclic trimethylolpropane formal (meth)acrylate, etc. As the (meth)acrylate containing a cyclic ether group, it is preferable to use either an oxetane ring-containing (meth)acrylate or a tetrahydrofuran ring-containing (meth)acrylate, with an oxetane ring-containing (meth)acrylate being more preferred.

[0062] Other (meth)acrylic acid ester compounds can also be used, and examples thereof include hydroxyalkyl (meth)acrylates such as 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, and 4-hydroxybutyl (meth)acrylate; alkoxyalkyl (meth)acrylates such as 2-methoxyethyl (meth)acrylate, 2-ethoxyethyl (meth)acrylate, and 2-butoxyethyl (meth)acrylate; alkoxyethylene glycol (meth)acrylates such as methoxyethylene glycol (meth)acrylate and ethoxyethylene glycol (meth)acrylate; and polyoxyethylene (meth)acrylates such as methoxydiethylene glycol (meth)acrylate, methoxytriethylene glycol (meth)acrylate, methoxypolyethylene glycol (meth)acrylate, ethyl carbitol (meth)acrylate, ethoxydiethylene glycol (meth)acrylate, ethoxytriethylene glycol (meth)acrylate, and ethoxypolyethylene glycol (meth)acrylate. As the (meth)acrylic acid ester compound other than the nitrogen-containing compound, it is preferable to use at least a cyclic ether group-containing (meth)acrylate, a polyoxyethylene (meth)acrylate, etc. The compound (C2) may be used alone or in combination of two or more kinds.

[0063] The compound (C2) may be appropriately selected from the above compounds so as to adjust the glass transition temperature after polymerization and to provide a certain level of viscoelasticity after curing. Although not particularly limited, it is also preferable to use a nitrogen-containing compound in combination with a compound that does not contain a nitrogen-containing compound (such as a (meth)acrylic acid ester compound) from the viewpoint of allowing photocuring to proceed appropriately even in the presence of oxygen.

[0064] The content of compound (C2) is preferably 15 to 70 parts by mass per 100 parts by mass of the moisture-curable resin composition. When the content of compound (C2) is equal to or greater than the above lower limit, it becomes easier to impart appropriate initial curability to the moisture-curable resin composition, and it also becomes easier to ensure shape retention after initial curing. It also makes it easier to improve the coatability of the moisture-curable resin composition. On the other hand, when the content is equal to or less than the above upper limit, the amount of moisture-curable resin can be made equal to or greater than a certain amount, and appropriate moisture curability can be imparted to the moisture-curable resin composition. From these viewpoints, the content of compound (C2) is more preferably 20 to 60 parts by mass, and even more preferably 30 to 50 parts by mass per 100 parts by mass of the moisture-curable resin composition.

[0065] [Photopolymerization initiator] The moisture-curable resin composition of the present invention preferably further contains a photopolymerization initiator. By containing the photopolymerization initiator, the moisture-curable resin composition can be appropriately imparted with photocurability. Examples of the photopolymerization initiator include benzophenone-based compounds, acetophenone-based compounds, acylphosphine oxide-based compounds, titanocene-based compounds, oxime ester-based compounds, benzoin ether-based compounds, and thioxanthone. Among the photopolymerization initiators, commercially available ones include, for example, Omnirad 184, Omnirad 369, Omnirad 379, Omnirad 651, Omnirad 784, Omnirad 819, Omnirad 907, Omnirad 2959, Omnirad TPO (all manufactured by IGM Resins), Irgacure OXE01 (manufactured by BASF), benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether (all manufactured by Tokyo Chemical Industry Co., Ltd.), etc. The photopolymerization initiators may be used alone or in combination of two or more.

[0066] The content of the photopolymerization initiator in the moisture-curable resin composition is preferably 0.01 parts by mass or more and 8 parts by mass or less, more preferably 0.1 parts by mass or more and 5 parts by mass or less, and even more preferably 0.3 parts by mass or more and 3 parts by mass or less, relative to 100 parts by mass of the moisture-curable resin composition. When the content of the photopolymerization initiator is within these ranges, the moisture-curable resin composition has excellent photocurability and storage stability. Furthermore, by setting it within the above range, the moisture-curable resin composition is appropriately photocured, making it easier to improve adhesive strength.

[0067] [Coupling Agent] The moisture-curable resin composition of the present invention may contain a coupling agent. By including a coupling agent in the moisture-curable resin composition, adhesive strength can be easily improved. Examples of the coupling agent include a silane coupling agent, a titanate-based coupling agent, and a zirconate-based coupling agent. Among the coupling agents, silane coupling agents are preferred because of their excellent effect of improving adhesiveness. Furthermore, among the silane coupling agents, mercaptan-based silane coupling agents, amine-based silane coupling agents, and isocyanate-based silane coupling agents are preferred, and among these, isocyanate-based silane coupling agents are more preferred.

[0068] Examples of amine-based silane coupling agents include N-phenyl-3-aminopropyltrimethoxysilane, 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-(2-aminoethyl)aminopropyltrimethoxysilane, 3-(2-aminoethyl)aminopropyltriethoxysilane, and 3-(2-aminoethyl)aminopropylmethyldimethoxysilane. Of these, N-phenyl-3-aminopropyltrimethoxysilane is preferred. Examples of mercaptan-based silane coupling agents include 3-mercaptopropyltrimethoxysilane, 3-mercaptopropylmethyldimethoxysilane, 3-mercaptopropyltriethoxysilane, and 3-mercaptopropylmethyldiethoxysilane. Examples of the isocyanate-based silane coupling agent include 3-isocyanatepropyltrimethoxysilane, 3-isocyanatepropylmethyldimethoxysilane, 3-isocyanatepropyltriethoxysilane, and 3-isocyanatepropylmethyldiethoxysilane, and among these, 3-isocyanatepropyltrimethoxysilane is preferred.Silane coupling agents other than those mentioned above may also be used, and examples thereof include 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, 3-glycidoxypropyltriethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, 3-(meth)acryloyloxypropyltrimethoxysilane, 3-(meth)acryloyloxypropyltriethoxysilane, 3-(meth)acryloyloxypropylmethyldimethoxysilane, 3-( Examples thereof include methacryloyloxypropylmethyldiethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, methyltrimethoxysilane, dimethyldimethoxysilane, phenyltrimethoxysilane, methyltriethoxysilane, dimethyldiethoxysilane, phenyltriethoxysilane, n-propyltrimethoxysilane, n-propyltriethoxysilane, hexyltrimethoxysilane, hexyltriethoxysilane, octyltriethoxysilane, tedyltrimethoxysilane, and 1,6-bis(trimethoxysilyl)hexane.

[0069] The content of the coupling agent is preferably 0.05 to 6 parts by mass, more preferably 0.2 to 4 parts by mass, and even more preferably 0.4 to 3 parts by mass, relative to 100 parts by mass of the moisture-curable resin composition. By keeping the content of the coupling agent within these ranges, it is easy to improve the adhesive strength without affecting various performance properties of the cured product.

[0070] [Filler] The moisture-curable resin composition of the present invention may contain a filler. By containing a filler, the moisture-curable resin composition of the present invention is more likely to have suitable thixotropy and to have good shape retention after application. A particulate filler may be used. As the filler, inorganic fillers are preferred, such as silica, talc, titanium oxide, zinc oxide, calcium carbonate, etc. Among them, silica is preferred because it provides the moisture-curable resin composition with excellent ultraviolet transmittance. The filler may also be subjected to a hydrophobic surface treatment such as silylation treatment, alkylation treatment, or epoxidation treatment. One type of filler may be used alone, or two or more types may be used in combination. The content of the filler is preferably 0.5 to 25 parts by mass, more preferably 1 to 20 parts by mass, and even more preferably 2 to 15 parts by mass, relative to 100 parts by mass of the moisture-curable resin composition.

[0071] In addition to the components described above, the moisture-curable resin composition of the present invention may contain other additives such as a moisture-cure accelerating catalyst, wax particles, ionic liquid, colorant, foamed particles, expanded particles, reactive diluent, antioxidant, and radical scavenger. The moisture-curable resin composition may be diluted with a solvent as needed. When the moisture-curable resin composition is diluted with a solvent, the amounts (parts by mass, %) of the moisture-curable resin composition are based on the solid content, i.e., the parts by mass and % by mass excluding the solvent.

[0072] Examples of a method for producing the moisture-curable resin composition of the present invention include a method of using a mixer to mix compound (A), compound (B), polymerizable compound (C), and additives such as a photopolymerization initiator, a filler, and a coupling agent, which are blended as needed. Examples of the mixer include a homodisper, a homomixer, a universal mixer, a planetary mixer (planetary stirring device), a kneader, and a three-roll mill.

[0073] (Elastic Modulus) The moisture-curable resin composition of the present invention may have a modulus of elasticity at 80 ° C of 0.1 MPa or more, preferably 0.5 MPa or more, more preferably 1.0 MPa or more, and even more preferably 1.5 MPa or more. Having a certain modulus or more makes it possible to maintain a certain modulus of elasticity even in a high-temperature environment, thereby increasing the final adhesive strength at high temperatures and improving reliability. The modulus of elasticity at 80 ° C of the cured product is not particularly limited, but may be, for example, 10 MPa or less. The storage modulus can be appropriately adjusted depending on the type of moisture-curable resin (compound (A), compound (B)), the type of polymerizable compound (C), and the content thereof.

[0074] In the present invention, the elastic modulus can be measured by the following method. A moisture-curable resin composition is poured into a Teflon (registered trademark) mold and cured to obtain a cured sample. Using the obtained cured sample, dynamic viscoelasticity is measured in the range of -100 to 150°C using a dynamic viscoelasticity measuring device, and the storage elastic modulus at 80°C is defined as the elastic modulus at 80°C.

[0075] The moisture-curable resin composition for producing a cured sample for measuring the storage modulus may be fully cured, but may be cured by the following method depending on the curing mechanism. In the case of a photo-curable moisture-curable resin composition, for example, a UV-LED (wavelength 365 nm) is used to irradiate ultraviolet light at 1000 mW / cm under an environment of 25°C and 50% RH. ２ at 4500 mJ / cm ２ The composition is then moisture-cured by leaving it in an environment of 25° C. and 50% RH for 24 hours. In addition, when the moisture-curable resin composition has thermosetting properties, the moisture-curable resin composition may be heated under conditions in which the polymerizable double bonds are polymerized, instead of being irradiated with light.

[0076] <Method of Use> The moisture-curable resin composition of the present invention may be cured and used as a cured product. For example, the moisture-curable resin composition may be placed between two adherends, and then the moisture-cured moisture-curable resin composition (cured product) may be used to bond the two adherends. The initial curing may be carried out appropriately depending on the polymerizable double bond contained in the compound (A) or the like. For example, if the polymerizable double bond is photopolymerizable, it may be carried out by light irradiation, and if the polymerizable double bond is thermally polymerizable, it may be carried out by heating. It is preferable that the polymerizable double bond contained in the compound (A) or the like is photopolymerizable as described above, and therefore, the initial curing may be carried out by light irradiation. Furthermore, the initial curing may be carried out so that the moisture-curable resin composition reaches a B-stage state (semi-cured state) upon curing.

[0077] Here, when the moisture-curable resin composition is placed between adherends and the adherends are bonded together, it is applied to one of the adherends and then initially cured (e.g., photocured) by light irradiation or the like, for example, to a B-stage state. The other adherend is then placed on top of the initially cured moisture-curable resin composition, and the adherends are temporarily bonded with an appropriate adhesive strength. The moisture-curable resin composition in the B-stage state is then fully cured by curing the moisture-curable resin containing compound (A) with moisture, and the superposed adherends are bonded with sufficient adhesive strength via the moisture-curable resin composition. The light irradiated when photocuring the moisture-curable resin composition is not particularly limited as long as it polymerizes the polymerizable double bonds, but ultraviolet light is preferred. Furthermore, when the moisture-curable resin composition is fully cured by moisture, it can be left in the atmosphere for a predetermined time.

[0078] The moisture-curable resin composition may be applied to an adherend using an automatic application device. The moisture-curable resin composition of the present invention has fluidity at room temperature and becomes fluid when heated, making it possible to apply it using an automatic application device. A dispenser is preferred as the automatic application device. Use of a dispenser allows for suitable application of thin lines. Examples of dispensers include an air dispenser, a jet dispenser, a mono-pump dispenser, a screw dispenser, and a handgun dispenser.

[0079] The moisture-curable resin composition of the present invention is used, for example, as an adhesive for electronic devices. The adhesive for electronic devices may contain the moisture-curable resin composition described above, but is typically composed of the moisture-curable resin composition. The moisture-curable resin composition of the present invention is preferably used for electronic devices, particularly liquid crystal display devices. The adherend for which the moisture-curable resin composition is used is not particularly limited, but is a component constituting an electronic device, particularly a liquid crystal display device, such as an electronic component or a substrate, housing, or display to which an electronic component is attached. The material of the adherend may be metal, glass, plastic, or the like. The shape of the adherend is not particularly limited, and examples thereof include a film, sheet, plate, panel, tray, rod, box, housing, and the like.

[0080] Examples of liquid crystal display devices include smartphones, mobile phones, tablet terminals, car navigation systems, portable game devices, notebook computers, desktop computers, televisions, and outdoor displays. The moisture-curable resin composition is preferably used for display fixing in liquid crystal display devices. When used for display fixing, a high load may be applied to the moisture-curable resin composition immediately after lamination. However, the moisture-curable resin composition of the present invention can appropriately bond adherends to each other without causing misalignment even when a high load is applied.

[0081] The present invention will be explained in more detail by way of examples, but the present invention is not limited to these examples in any way.

[0082] In the present examples and comparative examples, the moisture-curable resin compositions were evaluated as follows. (Elastic Modulus) According to the method described in the specification, cured samples of 3 mm wide, 30 mm long, and 1 mm thick were prepared from the moisture-curable resin compositions, and the storage modulus of the cured samples at 80°C was measured using a dynamic viscoelasticity measuring device (manufactured by IT Measurement Control Co., Ltd., product name "DVA-200"). The measurement conditions were: deformation mode: tensile, set strain: 0.1%, measurement frequency: 1 Hz, and heating rate: 5°C / min.

[0083] (Initial Retention Test) As shown in Figure 1 (A), first, an aluminum substrate 10 (AL6063 substrate) having a width of 25 mm, a length of 100 mm, and a thickness of 1 mm was prepared, and a moisture-curable resin composition 11 was applied at room temperature along the width direction of the substrate 10 using a dispenser to a length of 25 mm and a width of 2 mm. Next, ultraviolet light of 1000 mW / cm was applied using a UV-LED (wavelength 365 nm). ２ , 4500mJ / cm ２The sample was then irradiated with light to cure, and then left for 5 minutes in an environment of 25 ° C. and 50% RH. After leaving the sample in an environment of 25 ° C. and 50% RH, a glass plate 12 having a width of 25 mm, a length of 100 mm, and a thickness of 1.7 mm was placed on top of the photocured moisture-curing resin composition 11 as shown in FIG. 1 (B), and a 100 g weight 13 was placed on the glass plate 12 for 20 seconds to bond the glass plate 12 to the aluminum substrate 10 via the moisture-curing resin composition 11, thereby obtaining a test specimen 15. The glass plate 12 and the aluminum substrate 10 were overlapped by 30 mm in the length direction, and the moisture-curing resin composition 11 was positioned in the center of the overlapping portion of the substrate 10 and the glass plate 12. After removing the weight 13, the test specimen 15 was immediately fixed to the glass plate 12 so that the length direction was aligned vertically as shown in FIG. 1 (C). As shown in FIG. 1(C), a circular hole 16 having a diameter of 8 mm was provided in the center below the aluminum substrate 10. As shown in FIG. 1(D), a 60 g weight 17 was hung through the hole 16 for 5 minutes. After the hanging was completed, the elongation amount E of the moisture-curable resin composition 11 was measured as shown in FIG. 1(D). In FIG. 1(D), the two-dot chain line indicates the initial position of the moisture-curable resin composition 11. The initial position is the position where the moisture-curable resin composition 11 contacts the glass plate 12. The elongation amount E is the distance from the upper end of the initial position of the moisture-curable resin composition 11 to the lower end of the position of the moisture-curable resin composition 11 after the hanging was completed, and the most elongated part was measured. The distance was measured for the part of the moisture-curable resin composition 11 that contacted the glass plate 12. The ratio of the elongation amount E to the initial width (2 mm) of the moisture-curable resin composition 11 was defined as the elongation rate. The hanging of the weight and the measurement of the elongation amount E were carried out in an environment of 25° C. and 50% RH.

[0084] (Weight Amount in Final Hanging Test) In the final hanging test, the test specimen 15 obtained in the same manner as in the initial holding test was left for 24 hours in an atmosphere of 25°C and 50% RH to prepare a test specimen for the final hanging test. As with the test specimen for the initial holding test, the glass plate 12 of the obtained test specimen for the final hanging test was fixed so that the longitudinal direction was aligned with the vertical direction, and weights of 500 g, 600 g, and 700 g were hung from the aluminum substrate 10. The weight of the largest weight at which the aluminum substrate 10 did not fall off was defined as the weight amount in the final hanging test. Furthermore, if the aluminum substrate 10 fell off at 500 g, it was evaluated as "X." The final hanging test was conducted in an environment of 60°C and 90% RH.

[0085] (Room Temperature and High Temperature Adhesion Strength) As shown in Figure 2, the moisture-curable resin composition 20 was applied to an aluminum substrate 21 (AL6063 substrate) having a width of 25 mm, a length of 100 mm, and a thickness of 1 mm using a dispenser along the width direction of the substrate 21 to a length of 25 mm and a width of 1 mm. The photo-moisture-curable resin composition was applied at room temperature. Next, ultraviolet light was applied at 1000 mW / cm using a UV-LED (wavelength 365 nm). ２ , 4500mJ / cm ２ The sample was irradiated with light and photocured, and then left for 5 minutes in an environment of 25 ° C. and 50% RH. Then, a 25 mm wide, 100 mm long, and 1.7 mm thick glass plate 22 was bonded to the aluminum substrate 21 via the moisture-curing resin composition 20, and a 100 g weight was placed and pressed for 20 seconds. After removing the weight, the sample was left to moisture-cure at 25 ° C. and 50% RH for 24 hours to obtain a sample 23 for adhesive strength measurement. The sample 23 obtained by the above procedure was placed in a chamber-equipped universal testing machine at 25 ° C. and 50% RH for 10 minutes, and then the sample was placed in an adhesive strength measurement device (Shimadzu Corporation, "TCE-N300"). After 1 minute from the setting, a shear test was performed at a shear rate of 12.7 mm / min to measure the room temperature adhesive strength. Furthermore, a shear test was similarly performed on sample 23 obtained by the same procedure in an environment of 80 ° C. to measure the high-temperature adhesive strength.

[0086] The urethane prepolymers used in the examples and comparative examples were prepared as follows. <<Urethane Resin (AU)>> [Synthesis Example 1] Hydroxyl-terminated polybutadiene (manufactured by Idemitsu Kosan Co., Ltd., trade name: Poly bd ＴＭ Eighty-three parts by mass of a hydroxyl-terminated polybutadiene (R-45HT) was dehydrated at 100°C under reduced pressure for two hours. To the resulting dehydrated product, 17 parts by mass of diphenylmethane diisocyanate was added under a nitrogen atmosphere, and the reaction was carried out for two hours to obtain a urethane prepolymer (AU-1) having an isocyanate group at the molecular end. The number-average molecular weight of the hydroxyl-terminated polybutadiene was 3,000, and the [NCO] / [OH] ratio was 2.0. The polymerizable double bond group ratio of the urethane prepolymer (AU-1) was 8.3% by mass.

[0087] Synthesis Example 2 78 parts by mass of hydroxyl-terminated polybutadiene (manufactured by Evonic Corporation, trade name: PolyestHT) was dehydrated for 2 hours at 100°C under reduced pressure. 22 parts by mass of diphenylmethane diisocyanate was added to the resulting dehydrated product under a nitrogen atmosphere, and the mixture was allowed to react for 2 hours to obtain a urethane prepolymer (AU-2) having an isocyanate group at the molecular end. The number-average molecular weight of the hydroxyl-terminated polybutadiene was 2050, and the [NCO] / [OH] ratio was 2.5. The polymerizable double bond group ratio of the urethane prepolymer (AU-2) was 7.8% by mass.

[0088] Synthesis Example 3 Hydroxyl-terminated polybutadiene (manufactured by Idemitsu Kosan Co., Ltd., trade name: Poly bd ＴＭR-15HT) and 67.5 parts by mass of a polycarbonate diol mixture were mixed to obtain a polyol mixture, which was then dehydrated at 100°C under reduced pressure for 2 hours. The polycarbonate diol mixture was a mixture of 45.0 parts by mass of polycarbonate diol (manufactured by Mitsubishi Chemical Corporation, product name: NT-2006), 8.6 parts by mass of polycarbonate polyol (manufactured by Kuraray Co., Ltd., product name: Kuraray Polyol C-1090), and 13.9 parts by mass of polycarbonate polyol (manufactured by Kuraray Co., Ltd., product name: Kuraray Polyol C-590). 25 parts by mass of diphenylmethane diisocyanate was added to the dehydrated product obtained by the dehydration under a nitrogen atmosphere, and the mixture was allowed to react for 2 hours to obtain a urethane prepolymer (AU-3) having isocyanate groups at the molecular terminals. The number average molecular weight of the polyol mixture was 2050, and [NCO] / [OH] was 1.7. The polymerizable double bond group ratio of the urethane prepolymer (AU-3) was 0.75% by mass.

[0089] <<Urethane Resin (BU)>> [Synthesis Example 4] 62.1 parts by mass of polycarbonate polyol (manufactured by Kuraray Co., Ltd., product name: Kuraray Polyol C-3090) and 15.5 parts by mass of polycarbonate polyol (manufactured by Kuraray Co., Ltd., product name: Kuraray Polyol C-590) were mixed to obtain a polyol mixture, which was then dehydrated for 2 hours under reduced pressure at 100°C. 22.4 parts by mass of diphenylmethane diisocyanate was added to the resulting dehydrated product under a nitrogen atmosphere, and the mixture was allowed to react for 2 hours to obtain a urethane prepolymer (BU-1) having an isocyanate group at the molecular terminal. The number average molecular weight of the polyol mixture was 2730, and the [NCO] / [OH] ratio was 1.4. The urethane prepolymer (BU-1) had a polymerizable double bond group ratio of 0% by mass.

[0090] Synthesis Example 5 50.8 parts by mass of polycarbonate polyol (manufactured by Mitsubishi Chemical Corporation, trade name: NT-2006), 9.8 parts by mass of polycarbonate polyol (manufactured by Kuraray Co., Ltd., trade name: Kuraray Polyol C-1090), and 15.6 parts by mass of polycarbonate polyol (manufactured by Kuraray Co., Ltd., trade name: Kuraray Polyol C-590) were mixed to obtain a polyol mixture, which was then dehydrated at 100°C under reduced pressure for 2 hours. 23.9 parts by mass of diphenylmethane diisocyanate was added to the resulting dehydrated product under a nitrogen atmosphere, and the mixture was allowed to react for 2 hours to obtain a urethane prepolymer (BU-2) having an isocyanate group at the molecular end. The number average molecular weight of the polyol mixture was 3540, and the [NCO] / [OH] ratio was 1.4. The urethane prepolymer (BU-2) had a polymerizable double bond group ratio of 0% by mass.

[0091] Synthesis Example 6 52.4 parts by mass of polycarbonate polyol (manufactured by Mitsubishi Chemical Corporation, trade name: NT-2006), 10.0 parts by mass of polycarbonate polyol (manufactured by Kuraray Co., Ltd., trade name: Kuraray Polyol C-1090), and 16.1 parts by mass of polycarbonate polyol (manufactured by Kuraray Co., Ltd., trade name: Kuraray Polyol C-590) were mixed to obtain a polyol mixture, which was then dehydrated for 2 hours at 100°C under reduced pressure. 21.5 parts by weight of diphenylmethane diisocyanate was added to the resulting dehydrated product under a nitrogen atmosphere, and the mixture was allowed to react for 2 hours to obtain a urethane prepolymer (BU-3) having an isocyanate group at the molecular end. The number average molecular weight of the polyol mixture was 6000, and the [NCO] / [OH] ratio was 1.2. The urethane prepolymer (BU-3) had a polymerizable double bond group ratio of 0% by mass.

[0092] The components other than the urethane prepolymer used in each of the examples and comparative examples were as follows. (Compound (B1)) EBECRYL 4396: urethane acrylate, a compound having two isocyanate groups and one acryloyl group in one molecule, manufactured by Daicel Allnex Corporation, trade name "EBECRYL 4396" (Polymerizable Compound (C)) BISMER MPE400A: methoxypolyethylene glycol acrylate, manufactured by Osaka Organic Chemical Industry Ltd., trade name "BISMER MPE400A" MEDOL-10: (2-methyl-2-ethyl-1,3-dioxolan-4-yl)methyl acrylate, manufactured by Osaka Organic Chemical Industry Ltd., trade name "MEDOL-10" ACMO (registered trademark): acryloylmorpholine, manufactured by KJ Chemical Co., Ltd., trade name "ACMO (registered trademark)" V-Cap RC: N-vinyl-ε-caprolactam, manufactured by Ashland, trade name "V-Cap RC" CN8888: aliphatic urethane acrylate, urethane acrylate having acryloyl groups at both ends of the main chain (compound (C1)), manufactured by Sartomer, trade name "CN8888" (photopolymerization initiator) Omnirad651: photopolymerization initiator, manufactured by IGM Resins, trade name "Omnirad651" Omnirad819: photopolymerization initiator, manufactured by IGM Resins, trade name "Omnirad819" (filler) silica, manufactured by Nippon Aerosil Co., Ltd., trade name "RY-200S" (coupling agent) Momentive Performance Materials, trade name "A-Link35", 3-isocyanatepropyltrimethoxysilane

[0093] [Examples 1 to 6, Comparative Examples 1 and 2] According to the formulations shown in Table 1, the materials were uniformly mixed to obtain moisture-curable resin compositions of Examples 1 to 6 and Comparative Examples 1 and 2.

[0094]

[0095] As shown in Table 1, in each example, the moisture-curable resin composition contained a compound (A) having at least one isocyanate group at the end of the molecule and two or more polymerizable double bonds in the molecule. Therefore, by photocuring, initial deformation under high load can be suppressed even immediately after lamination of the component, and initial adhesion was improved. In addition, the moisture-curable resin composition had high adhesive strength at both room temperature and high temperature, a large weight in the final hanging test, high final adhesive strength, and excellent reliability. In contrast, the moisture-curable resin composition in Comparative Example 1 did not contain compound (A), and therefore, even after photocuring, it was not possible to sufficiently suppress initial deformation under high load immediately after lamination of the component. In addition, the moisture-curable resin composition in Comparative Example 2 did not have sufficiently high high-temperature adhesive strength, and it could not be said to have sufficiently excellent reliability.

Claims

1. A moisture-curable resin composition containing a compound (A) having at least one isocyanate group at the end of the molecule and having two or more polymerizable double bonds in the molecule.

2. The moisture-curable resin composition according to claim 1, wherein the compound (A) is a compound having a polymerizable double bond at the end of a side chain, and further comprising, in addition to the compound (A), a polymerizable compound (C) that does not contain an isocyanate group, and a photopolymerization initiator.

3. The moisture-curable resin composition according to claim 2, wherein the compound (A) comprises a urethane resin (AU) that is a reaction product of a polyol (a1) and a polyfunctional isocyanate (a2), and the polyol (a1) comprises a polyol having a polymerizable double bond in the molecule.

4. The moisture-curable resin composition according to claim 3, wherein the polyol having a polymerizable double bond in the molecule comprises a polybutadiene polyol having a 1,2-bond in the molecule.

5. The moisture-curable resin composition according to claim 3, wherein the polyol (a1) further comprises a polyol having no polymerizable double bond in the molecule.

6. The moisture-curable resin composition according to claim 2, further comprising, in addition to the compound (A), a compound (B) having an isocyanate group at the molecular terminal.

7. The moisture-curable resin composition according to claim 6, wherein the compound (B) includes a compound (B1) having two or more isocyanate groups at the ends of its molecule.

8. The moisture-curable resin composition according to claim 2, wherein the polymerizable compound (C) includes a compound (C1) having polymerizable double bonds at both ends of the main chain.

9. The moisture-curable resin composition according to claim 8, wherein the polymerizable compound (C) further contains a monofunctional compound (C2) having one polymerizable double bond.

10. A moisture-curable resin composition according to claim 2, wherein the proportion of polymerizable double bond groups in the moisture-curable resin is 0.1% by mass or more and 1.5% by mass or less.

11. The moisture-curable resin composition according to claim 10, wherein the isocyanate group content is 1% by mass or more.

12. An adhesive for electronic devices, comprising the moisture-curable resin composition according to any one of claims 1 to 11.

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