Adhesive composition and adhesive sheet

Abstract

The present invention provides a pressure-sensitive adhesive composition which contains: (A) an isobutene-based polymer having a crosslinked structure formed from a reaction between an epoxy group and an acid anhydride group and / or carboxyl group; and (B) at least one type selected from the group consisting of an alkoxide having a divalent or higher metal as a central metal, a carboxylate having a divalent or higher metal as a central metal, and a chelate compound having a divalent or higher metal as a central metal. The isobutene-based polymer has, as a side chain, a polymer chain containing a constituent unit derived from an alkyl (meth)acrylate in which the alkyl group has 6 or more carbon atoms.

Description

Technical Field

[0001] The present invention relates to an adhesive composition and an adhesive sheet.

Background Art

[0002] In order to manufacture a flexible electronic device that is flexible and foldable, a laminate obtained by laminating a plurality of films or sheets is used. In the laminate used for manufacturing a flexible electronic device, in addition to the durability required in the manufacture of conventional electronic devices, it is required to be able to suppress the occurrence of peeling or lifting even when bent (that is, to have excellent bending resistance). Therefore, the adhesive composition used for forming the laminate is required to have excellent adhesiveness and bending resistance.

[0003] For example, Patent Document 1 discloses a sealing composition useful for manufacturing a flexible electronic device, which contains a polyolefin resin and / or a polyolefin rubber, an inorganic filler, and a metal complex in which a bidentate ligand having two coordinating atoms both being oxygen atoms and a monodentate ligand having a coordinating atom being an oxygen atom are bonded to a central metal.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] Polyimide is often used as a part of the laminate constituting a flexible electronic device. Therefore, an adhesive composition having excellent adhesiveness to polyimide (especially adhesiveness at high temperatures) and bending resistance is required.

[0006] The present invention has been made in view of the above circumstances, and its objective is to provide an adhesive composition with excellent adhesion and bending resistance (particularly adhesion and bending resistance to polyimide at high temperatures). [Means for solving the problem]

[0007] The present invention, which can achieve the above-mentioned objectives, is as follows: [1] (A) Isobutene polymers having a crosslinked structure formed by the reaction of epoxy groups with acid anhydride groups and / or carboxyl groups, and (B) At least one selected from the group consisting of alkoxides with a divalent or higher metal as the central metal, carboxylates with a divalent or higher metal as the central metal, and chelate compounds with a divalent or higher metal as the central metal. An adhesive composition comprising, The adhesive composition wherein the isobutene polymer has a polymer chain containing a structural unit derived from an alkyl (meth)acrylate having an alkyl group with 6 or more carbon atoms as a side chain. [2] The adhesive composition according to [1], wherein the concentration of constituent units derived from alkyl (meth)acrylate having an alkyl group having 6 or more carbon atoms in the isobutene polymer is 0.005 to 5 mmol / g. [3] The isobutene polymer is (a1) Reaction products of an isobutene-isoprene copolymer having an epoxy group and an olefin polymer having an acid anhydride group and / or a carboxyl group, and (a2) Reaction product of an isobutene-isoprene copolymer having an acid anhydride group and / or a carboxyl group with an olefin polymer having an epoxy group At least one selected from the group consisting of, and The adhesive composition according to [1] or [2], wherein at least one of the isobutene-isoprene copolymer and the olefin polymer has a polymer chain containing a structural unit derived from an alkyl (meth)acrylate having an alkyl group having 6 or more carbon atoms as a side chain. [4] The adhesive composition according to any one of [1] to [3] above, wherein the metal with a valence of 2 or more is a metal of Group 4 of the periodic table or a metal of Group 13 of the periodic table. [5] The adhesive composition according to any one of [1] to [3], wherein the metal with a valence of 2 or more is aluminum, titanium, or zirconium. [6] (C) The adhesive composition according to any one of [1] to [5], further comprising a liquid polyolefin resin and / or liquid rubber. [7] An adhesive sheet having a laminated structure including an adhesive composition layer formed from any one of the adhesive compositions described in [1] to [6] above, and a support. [Effects of the Invention]

[0008] According to the present invention, an adhesive composition with excellent adhesion and bending resistance (particularly adhesion and bending resistance to polyimide at high temperatures) can be obtained. [Modes for carrying out the invention]

[0009] The adhesive composition of the present invention is (A) Isobutene polymers having a crosslinked structure formed by the reaction of epoxy groups with acid anhydride groups and / or carboxyl groups, and (B) At least one selected from the group consisting of alkoxides with a divalent or higher metal as the central metal, carboxylate compounds of a divalent or higher metal, and chelate compounds of a divalent or higher metal. The present invention comprises the isobutene polymer, characterized in that the isobutene polymer has polymer chains containing structural units derived from alkyl (meth)acrylates having an alkyl group with 6 or more carbon atoms as side chains.

[0010] In this specification, “alkyl (meth)acrylate” means “alkyl acrylate or alkyl methacrylate.” Both alkyl acrylate and alkyl methacrylate may be used.

[0011] The number of carbon atoms in the alkyl(meth)acrylate having an alkyl group must be 6 or more from the viewpoint of adhesion. Preferably, the number of carbon atoms is 7 or more, and more preferably 8 or more. There is no particular upper limit to the number of carbon atoms, but from the viewpoint of lowering the glass transition temperature of the adhesive composition to make it suitable for flexible electronic device applications, the number of carbon atoms is preferably 30 or less, more preferably 24 or less, even more preferably 22 or less, still more preferably 20 or less, even more preferably 18 or less, particularly preferably 16 or less, particularly more preferably 14 or less, and most preferably 12 or less. The alkyl group may be linear or branched.

[0012] In this specification, "alkyl (meth)acrylate having an alkyl group with 6 or more carbon atoms" may be abbreviated as "long-chain alkyl (meth)acrylate," and "constituent units derived from long-chain alkyl (meth)acrylate" may be abbreviated as "long-chain alkyl (meth)acrylate unit." Other constituent units may also be abbreviated similarly.

[0013] In this specification, "polymer chains containing long-chain alkyl (meth)acrylate units" may be abbreviated as "long-chain alkyl (meth)acrylate polymer chains," and "isobutene polymers having a crosslinked structure formed by the reaction of epoxy groups with acid anhydride groups and / or carboxyl groups, and long-chain alkyl (meth)acrylate polymer chains as side chains" may be abbreviated as "crosslinked isobutene polymers having long-chain alkyl (meth)acrylate polymer chains."

[0014] In this specification, "a crosslinked isobutene polymer having a long-chain alkyl (meth)acrylate polymer chain" may be referred to as "component (A)," and "(B) at least one selected from the group consisting of alkoxides with a divalent or higher metal as the central metal, carboxylate compounds of a divalent or higher metal, and chelate compounds of a divalent or higher metal" may be referred to as "component (B)."

[0015] In the present invention, by using the component (A), the adhesiveness at high temperature to polyimide can be improved. As its mechanism, it is presumed that since the component (A) has a long-chain alkyl (meth)acrylate polymer chain, the cohesive force of the component (A) is improved, and as a result, the adhesiveness of the adhesive composition containing the component (A) is improved. However, the present invention is not limited to such a presumed mechanism.

[0016] In the present invention, by using the component (A) and the component (B) in combination, the bending resistance can be improved. As its mechanism, it is presumed that the carboxyl group and / or hydroxy group in the component (A) formed by the reaction of an epoxy group with an acid anhydride group and / or a carboxyl group and the component (B) are crosslinked, whereby the bending resistance of the adhesive composition containing the component (A) and the component (B) is improved. However, the present invention is not limited to such a presumed mechanism.

[0017] Hereinafter, the components that can be used in the adhesive composition of the present invention will be described in order. Each component may be used alone or in combination of two or more.

[0018] <Component (A)> The adhesive composition of the present invention contains a crosslinked isobutene-based polymer ((A) component) having a long-chain alkyl (meth)acrylate polymer chain. The side chain (that is, the long-chain alkyl (meth)acrylate polymer chain) may be formed from a homopolymer or a copolymer. The copolymer may be a block copolymer or a random copolymer. The crosslinked structure in the component (A) is preferably formed by the reaction of an epoxy group with an acid anhydride group.

[0019] Component (A) may contain only one type of long-chain alkyl (meth)acrylate unit, or it may contain two or more types of long-chain alkyl (meth)acrylate units. Examples of long-chain alkyl (meth)acrylates include 2-ethylhexyl (meth)acrylate, octyl (meth)acrylate, nonyl (meth)acrylate, decyl (meth)acrylate, undecyl (meth)acrylate, and dodecyl (meth)acrylate (also known as lauryl (meth)acrylate). Among these, 2-ethylhexyl (meth)acrylate and lauryl (meth)acrylate are preferred, and 2-ethylhexyl acrylate and lauryl methacrylate are more preferred.

[0020] The concentration of long-chain alkyl (meth)acrylate units in component (A) is preferably 0.005 to 5 mmol / g, more preferably 0.007 to 3 mmol / g, and even more preferably 0.01 to 1 mmol / g. Here, "concentration of long-chain alkyl (meth)acrylate units in component (A)" means the amount (mmol) of long-chain alkyl (meth)acrylate units per gram of component (A). The same applies to the concentrations of other units. The concentration of long-chain alkyl (meth)acrylate units in component (A) can be calculated, for example, from the concentration of long-chain alkyl (meth)acrylate units in the raw material of component (A) (for example, the isobutene-isoprene copolymer having epoxy groups described later). Alternatively, the concentration of long-chain alkyl (meth)acrylate units in the raw material of component (A) can be calculated from the amount of monomer used during its synthesis.

[0021] In this specification, "isobutene polymer" means a polymer in which isobutene-derived constituent units (hereinafter sometimes abbreviated as "isobutene units") are the main constituent units (i.e., the amount of isobutene units is the largest among all constituent units). The isobutene polymer is preferably an isobutene-isoprene copolymer (i.e., butyl rubber). In the present invention, the amount of isoprene units in the isobutene-isoprene copolymer is preferably 0.1 to 20% by mass, more preferably 0.3 to 15% by mass, and even more preferably 0.5 to 10% by mass, based on the total of isobutene units and isoprene units.

[0022] In one aspect of the present invention (hereinafter referred to as "Aspect (1)"), component (A) is: (a1) Reaction products of an isobutene-isoprene copolymer having an epoxy group and an olefin polymer having an acid anhydride group and / or a carboxyl group (hereinafter sometimes referred to as "reaction product (a1)"), and (a2) Reaction product of an isobutene-isoprene copolymer having an acid anhydride group and / or a carboxyl group with an olefin polymer having an epoxy group (hereinafter sometimes referred to as "reaction product (a2)") At least one selected from the group consisting of, and At least one of the isobutene-isoprene copolymer and the olefin polymer has a long-chain alkyl (meth)acrylate polymer chain as a side chain.

[0023] In this specification, "olefin polymer" means a polymer in which the main constituent units are olefin-derived units (hereinafter sometimes abbreviated as "olefin units") (i.e., in which the amount of olefin units is the largest among all constituent units).

[0024] Preferred olefins are monoolefins having one olefinic carbon-carbon double bond and / or diolefins having two olefinic carbon-carbon double bonds. Examples of monoolefins include α-olefins such as ethylene, propylene, 1-butene, isobutene (isobutylene), 1-pentene, 1-hexene, 1-heptene, and 1-octene. Examples of diolefins include 1,3-butadiene, isoprene, 1,3-pentadiene, and 2,3-dimethylbutadiene.

[0025] The olefin polymer may be a homopolymer or a copolymer. The copolymer may be a random copolymer or a block copolymer. Furthermore, the olefin polymer may be a copolymer of an olefin and a monomer other than an olefin.

[0026] In embodiment (1), the isobutene-isoprene copolymer and the olefin polymer may be used individually or in combination of two or more.

[0027] In embodiment (1), the acid anhydride group and / or carboxyl group is preferably an acid anhydride group. Also in embodiment (1), the olefin polymer is preferably an isobutene polymer, and more preferably an isobutene-isoprene copolymer (i.e., butyl rubber).

[0028] In embodiment (1), the concentration of epoxy groups in the isobutene-isoprene copolymer having epoxy groups and the concentration of epoxy groups in the olefin polymer having epoxy groups are, independently, preferably 0.01 to 10 mmol / g, and more preferably 0.05 to 5 mmol / g. This epoxy group concentration is determined from the epoxy equivalent obtained according to JIS K 7236-1995.

[0029] In embodiment (1), the concentration of acid anhydride groups in the isobutene-isoprene copolymer having acid anhydride groups, and the concentration of acid anhydride groups in the olefin polymer having acid anhydride groups, are each preferably 0.01 to 10 mmol / g, more preferably 0.05 to 5 mmol / g. The concentration of acid anhydride groups is determined from the acid value, which is defined as the number of mg of potassium hydroxide required to neutralize the acid present in 1 g of resin, according to JIS K 2501.

[0030] In embodiment (1), the concentration of carboxyl groups in the isobutene-isoprene copolymer having carboxyl groups and the concentration of carboxyl groups in the olefin polymer having carboxyl groups are, independently, preferably 0.01 to 10 mmol / g, and more preferably 0.05 to 5 mmol / g. The concentration of carboxyl groups is determined from the acid value, which is defined as the number of mg of potassium hydroxide required to neutralize the acid present in 1 g of resin, according to the description in JIS K 2501.

[0031] In embodiment (1), the sum of the concentrations of acid anhydride groups and carboxyl groups in the isobutene-isoprene copolymer having acid anhydride groups and carboxyl groups (i.e., "concentration of acid anhydride groups + concentration of carboxyl groups"), and the sum of the concentrations of acid anhydride groups and carboxyl groups in the olefin polymer having acid anhydride groups and carboxyl groups, are each preferably 0.01 to 10 mmol / g, more preferably 0.05 to 5 mmol / g.

[0032] In embodiment (1), the number-average molecular weight (hereinafter sometimes referred to as "Mn") of the isobutene-isoprene copolymer having epoxy groups, the Mn of the olefin polymer having acid anhydride groups and / or carboxyl groups, the Mn of the isobutene-isoprene copolymer having acid anhydride groups and / or carboxyl groups, and the Mn of the olefin polymer having epoxy groups are each preferably 1,000 to 1,000,000, more preferably 20,000 to 500,000, and even more preferably 50,000 to 500,000. In this specification, Mn is a value measured by gel permeation chromatography (GPC) (in polystyrene terms). Specifically, the number-average molecular weight can be calculated using the GPC method by measuring with a Shimadzu LC-9A / RID-6A measuring instrument, a Showa Denko Shodex K-800P / K-804L / K-804L column, and toluene or the like as the mobile phase, at a column temperature of 40°C, and then using a calibration curve for standard polystyrene.

[0033] In embodiment (1), the amount of isoprene units in component (A) is preferably 0.1 to 20% by mass, more preferably 0.3 to 15% by mass, and even more preferably 0.5 to 10% by mass, based on the total of isobutene units and isoprene units.

[0034] The ratio of the amount of epoxy groups (mol) in the epoxy-containing isobutene-isoprene copolymer to the amount of acid anhydride groups (mol) in the olefin polymer containing acid anhydride groups (i.e., "amount of epoxy groups (mol): amount of acid anhydride groups (mol)") for forming the reaction product (a1) is preferably 100:20 to 100:1,000, more preferably 100:30 to 100:400, and even more preferably 100:50 to 100:300.

[0035] The ratio of the amount of epoxy groups (mol) in the epoxy-containing isobutene-isoprene copolymer to the amount of acid anhydride groups (mol) in the olefin polymer containing carboxyl groups (i.e., "amount of epoxy groups (mol): amount of carboxyl groups (mol)") for forming the reaction product (a1) is preferably 100:20 to 100:1,000, more preferably 100:30 to 100:400, and even more preferably 100:50 to 100:300.

[0036] For forming the reaction product (a1), the ratio of the amount of epoxy groups (mol) in the epoxy-containing isobutene-isoprene copolymer to the sum of the amount of acid anhydride groups (mol) and carboxyl groups (mol) in the olefin polymer containing carboxyl groups and acid anhydride groups (i.e., "amount of epoxy groups (mol): (amount of acid anhydride groups (mol) + amount of carboxyl groups (mol))") is preferably 100:20 to 100:1,000, more preferably 100:30 to 100:400, and even more preferably 100:50 to 100:300.

[0037] The ratio of epoxy groups (mol) to acid anhydride groups (mol) for forming reaction product (a2) is the same as the corresponding preferred range described for reaction product (a1) (i.e., the preferred range for the ratio of epoxy groups (mol) to acid anhydride groups (mol) for forming reaction product (a1)). The preferred ranges for the ratio of epoxy groups (mol) to carboxyl groups (mol) and the ratio of epoxy groups (mol) to carboxyl groups (mol) for forming reaction product (a2) are also the same as the corresponding preferred ranges described for reaction product (a1).

[0038] In one aspect of the present invention (hereinafter referred to as "Aspect (2)"), component (A) is: (a3) A reaction product of an isobutene-isoprene copolymer having polymer chains containing epoxy groups and long-chain alkyl (meth)acrylate units as side chains, and an olefin polymer having acid anhydride groups and / or carboxyl groups (hereinafter sometimes referred to as "reaction product (a3)"), (a4) Reaction products of an isobutene-isoprene copolymer having polymer chains containing acid anhydride groups and / or carboxyl groups and long-chain alkyl (meth)acrylate units as side chains, and an olefin polymer having epoxy groups (hereinafter sometimes referred to as "reaction product (a4)"), and (a5) Reaction product of an isobutene-isoprene copolymer having polymer chains containing epoxy groups and long-chain alkyl (meth)acrylate units as side chains, and an isobutene-isoprene copolymer having polymer chains containing acid anhydride groups and / or carboxyl groups and long-chain alkyl (meth)acrylate units as side chains (hereinafter sometimes referred to as "reaction product (a5)"). It is at least one selected from the group consisting of [the specified characters].

[0039] In embodiment (2), the isobutene-isoprene copolymer and the olefin polymer may be used individually or in combination of two or more.

[0040] In embodiment (2), component (A) is preferably at least one selected from the group consisting of reaction product (a3) ​​and reaction product (a4). Also in embodiment (2), the acid anhydride group and / or carboxyl group is preferably an acid anhydride group. Also in embodiment (2), the olefin polymer is preferably an isobutene polymer, and more preferably an isobutene-isoprene copolymer (i.e., butyl rubber).

[0041] In embodiment (2), (i) The "concentration of epoxy groups", "concentration of acid anhydride groups", "concentration of carboxyl groups", and "sum of the concentrations of acid anhydride groups and carboxyl groups" in each polymer for forming reaction product (a3), reaction product (a4), and reaction product (a5), (ii) Mn of each polymer, (iii) The amount of isoprene units in component (A), and (iv) The amounts of epoxy groups (mol) to acid anhydride groups (mol) for forming reaction products (a3), (a4), and (a5), respectively: "Amount of epoxy groups (mol) to amount of carboxyl groups (mol)", and "Amount of epoxy groups (mol) to (Amount of acid anhydride groups (mol) + Amount of carboxyl groups (mol))". The preferred ranges, etc., are the same as the corresponding preferred ranges, etc., described in Embodiment (1) or Reaction Product (a1), respectively.

[0042] Examples of isobutene-isoprene copolymers having polymer chains containing epoxy groups and long-chain alkyl (meth)acrylate units as side chains include butyl rubber modified by a copolymer of an epoxy group-containing unsaturated compound and a long-chain alkyl (meth)acrylate (i.e., isobutene-isoprene copolymer). Here, "butyl rubber modified by a copolymer" means "butyl rubber having the copolymer chain as a side chain." In this specification, this "butyl rubber modified by a copolymer" may be referred to as "polymer-modified butyl rubber." Examples of epoxy group-containing unsaturated compounds include glycidyl (meth)acrylate, 4-hydroxybutyl acrylate glycidyl ether, and allyl glycidyl ether. Only one epoxy group-containing unsaturated compound may be used, or two or more may be used in combination. The epoxy group-containing unsaturated compound is preferably glycidyl (meth)acrylate.

[0043] Examples of isobutene-isoprene copolymers having polymer chains containing acid anhydride groups and / or carboxyl groups and long-chain alkyl (meth)acrylate units as side chains include butyl rubber modified by a copolymer of a carboxylic acid anhydride and a long-chain alkyl (meth)acrylate (i.e., isobutene-isoprene copolymer). Examples of carboxylic acid anhydrides include succinic anhydride, maleic anhydride, and glutaric anhydride. Only one carboxylic acid anhydride may be used, or two or more may be used in combination. Maleic anhydride is preferred as the carboxylic acid anhydride.

[0044] The epoxy group-containing unsaturated compound-long-chain alkyl (meth)acrylate copolymer-modified butyl rubber used in embodiment (2) can be produced, for example, by grafting monomers (i.e., epoxy group-containing unsaturated compound and long-chain alkyl (meth)acrylate) or epoxy group-containing unsaturated compound-long-chain alkyl (meth)acrylate copolymer onto butyl rubber. Carboxylic acid anhydride-long-chain alkyl (meth)acrylate copolymer-modified butyl rubber can be produced in the same manner. These modified butyl rubbers can be obtained, for example, from Seikoh PMC Co., Ltd.

[0045] The olefin polymer having acid anhydride groups and / or carboxyl groups used in embodiment (1) or (2) (for example, isobutene-isoprene copolymer having acid anhydride groups and / or carboxyl groups) can be produced by graft modification of the olefin polymer with an unsaturated compound having acid anhydride groups and / or carboxyl groups (for example, maleic anhydride) under radical reaction conditions.

[0046] Examples of olefin polymers having acid anhydride groups and / or carboxyl groups used in embodiment (1) or (2) include the following. Examples of isobutene-isoprene copolymers having acid anhydride groups and / or carboxyl groups include "ER661" (maleic anhydride-butyl methacrylate random copolymer modified butyl rubber) manufactured by Seikoh PMC. Examples of olefin polymers having acid anhydride groups and / or carboxyl groups (excluding isobutene-isoprene copolymers) include "HV-300M" (maleic anhydride-modified polybutene) manufactured by Toho Chemical Industry Co., Ltd., "T-YP279" (maleic anhydride-modified propylene-butene random copolymer) manufactured by Seikoh PMC Co., Ltd., "T-YP312" (maleic anhydride-modified propylene-butene random copolymer) manufactured by Seikoh PMC Co., Ltd., and "Lucant A-5260" (maleic anhydride-modified ethylene-α-olefin random copolymer) and "Lucant A-5320" (maleic anhydride-modified ethylene-α-olefin random copolymer) manufactured by Mitsui Chemicals, Inc.

[0047] The epoxy-group-containing olefin polymer used in embodiment (1) or (2) (for example, isobutene-isoprene copolymer having epoxy groups) can be produced by graft modification of the olefin polymer under radical reaction conditions using an epoxy-group-containing unsaturated compound (for example, glycidyl (meth)acrylate, 4-hydroxybutyl acrylate glycidyl ether, allyl glycidyl ether).

[0048] Examples of olefin polymers having epoxy groups used in embodiment (1) or (2) include the following: Examples of isobutene-isoprene copolymers having epoxy groups include "ER866" (glycidyl methacrylate-modified butyl rubber) and "ER850" (glycidyl methacrylate-modified butyl rubber) manufactured by Seikoh PMC. Examples of olefin polymers having epoxy groups (excluding isobutene-isoprene copolymers) include "T-YP341" (glycidyl methacrylate-modified propylene-butene random copolymer) and "T-YP276" (glycidyl methacrylate-modified propylene-butene random copolymer) manufactured by Seikoh PMC.

[0049] The content of component (A) in the adhesive composition is preferably 10% by mass or more, more preferably 20% by mass or more, even more preferably 30% by mass or more, preferably 90% by mass or less, more preferably 85% by mass or less, and even more preferably 80% by mass or less, based on 100% by mass of the nonvolatile content of the adhesive composition, from the viewpoint of adhesion and bending resistance.

[0050] <(B) component> The adhesive composition of the present invention comprises at least one selected from the group consisting of alkoxides with a divalent or higher metal (hereinafter sometimes simply referred to as "metal") as the central metal (hereinafter sometimes referred to as "metal alkoxide"), carboxylates with a divalent or higher metal as the central metal (hereinafter sometimes referred to as "metal carboxylate"), and chelate compounds with a divalent or higher metal as the central metal (hereinafter sometimes referred to as "metal chelate compound").

[0051] In this invention, "metal alkoxide" means a compound containing a structure represented by M-OR (wherein M represents a metal with a valency of 2 or higher, and R represents an organic group), and "metal carboxylate" means a compound containing a structure represented by MO-(CO)-R (wherein M represents a metal with a valency of 2 or higher, and R represents an organic group). Furthermore, "metal chelate compound" means a compound containing a chelate ring structure formed by the bonding of a polydentate ligand to a central metal that is a metal with a valency of 2 or higher. Compounds having both a chelate ring structure and a structure represented by M-OR or MO-(CO)-R are classified as "metal chelate compounds" in this invention.

[0052] The metal with a valency of 2 or higher is preferably a metal from Group 4 or Group 13 of the periodic table, and more preferably aluminum, titanium, or zirconium.

[0053] Examples of polydentate ligands that can be used to form metal chelate compounds include those shown in formula (a):

[0054] [ka]

[0055] Examples include compounds represented by [In formula (a), the definitions of R1, R2, and R3 are the same as those in formula (1) described later.] (hereinafter sometimes referred to as "compound (a)").

[0056] Compound (a) represents a polydentate ligand before coordination to the central metal. In this invention, a polydentate ligand in the state of coordination to the central metal and a polydentate ligand before coordination to the central metal are sometimes referred to simply as a "polydentate ligand" without any particular distinction. Specific examples of the compound represented by formula (a) are the same as the specific examples of the polydentate ligand in the compound represented by formula (1) described later.

[0057] Component (B) is preferably the following formula (1):

[0058] [ka]

[0059] [In formula (1), M represents a metal with a valent or higher valency. R1 and R3 independently represent a hydrogen atom, an alkyl group, an alkenyl group, an alkynyl group, an alkoxy group, an alkenyloxy group, an aryl group, or an aralkyl group. R2 represents a hydrogen atom, an alkyl group, an alkenyl group, an alkynyl group, an alkoxy group, an alkenyloxy group, an alkoxycarbonyl group, an aryl group, or an aralkyl group. X represents a monosequence ligand, In equation (1), the solid line between the oxygen atom (O) and M in the brackets [ ] represents a covalent bond. In equation (1), the dashed line between the oxygen atom (O) and M in the brackets [ ] represents a coordinate bond, and m represents 3 or 4, and n represents an integer between 0 and 4, where m ≥ n. This is a metal complex represented by (hereinafter sometimes abbreviated as "metal complex (1)"). Metal complex (1) may be used alone or in combination of two or more types.

[0060] Examples of halogen atoms in this specification include fluorine atoms, chlorine atoms, bromine atoms, and iodine atoms.

[0061] In this specification, alkyl groups may be linear or branched. The number of carbon atoms in an alkyl group (excluding alkyl groups in long-chain alkyl (meth)acrylates) is preferably 1 to 20, more preferably 1 to 10, and particularly preferably 1 to 6. Examples of alkyl groups include methyl, ethyl, propyl, isopropyl, butyl, isobutyl, sec-butyl, tert-butyl, pentyl, isopentyl, neopentyl, 1-ethylpropyl, hexyl, isohexyl, 1,1-dimethylbutyl, 2,2-dimethylbutyl, 3,3-dimethylbutyl, and 2-ethylbutyl groups. Alkyl groups may have substituents. Examples of substituents include halogen atoms, hydroxyl groups, and optionally substituted amino groups.

[0062] In this specification, the alkenyl group may be linear or branched. The number of carbon atoms in the alkenyl group is preferably 2 to 20. Examples of alkenyl groups include ethenyl group (i.e., vinyl group), 1-propenyl group, 2-propenyl group, 2-methyl-1-propenyl group, 1-butenyl group, 2-butenyl group, 3-butenyl group, 3-methyl-2-butenyl group, 1-pentenyl group, 2-pentenyl group, 3-pentenyl group, 4-pentenyl group, 4-methyl-3-pentenyl group, 1-hexenyl group, 3-hexenyl group, and 5-hexenyl group. The alkenyl group may have substituents. Examples of substituents include halogen atoms, hydroxyl groups, and optionally substituted amino groups.

[0063] In this specification, the alkynyl group may be linear or branched. The number of carbon atoms in the alkynyl group is preferably 2 to 10, more preferably 2 to 6. Examples of alkynyl groups include ethynyl, 1-propynyl, 2-propynyl, 1-butynyl, 2-butynyl, 3-butynyl, 1-pentynyl, 2-pentynyl, 3-pentynyl, 4-pentynyl, 1-hexynyl, 2-hexynyl, 3-hexynyl, 4-hexynyl, 5-hexynyl, and 4-methyl-2-pentynyl. The alkynyl group may have substituents. Examples of substituents include halogen atoms, hydroxyl groups, and optionally substituted amino groups.

[0064] In this specification, the number of carbon atoms in the aryl group is preferably 6 to 18, more preferably 6 to 14. Examples of aryl groups include phenyl, 1-naphthyl, 2-naphthyl, 1-anthryl, 2-anthryl, and 9-anthryl groups. The aryl group may have substituents. Examples of substituents include halogen atoms, hydroxyl groups, optionally substituted alkyl groups, optionally substituted alkenyl groups, optionally substituted alkynyl groups, and optionally substituted amino groups.

[0065] In this specification, the number of carbon atoms in the aralkyl group is preferably 7 to 16. Examples of aralkyl groups include benzyl groups, phenethyl groups, naphthylmethyl groups, and phenylpropyl groups. The aralkyl group may have substituents. Examples of substituents include halogen atoms, hydroxyl groups, and optionally substituted amino groups.

[0066] In this specification, examples of amino groups that may have substituents include amino groups, mono- or di-alkylamino groups (e.g., methylamino group, dimethylamino group, ethylamino group, diethylamino group, propylamino group, dibutylamino group), mono- or di-cycloalkylamino groups (e.g., cyclopropylamino group, cyclohexylamino group), mono- or di-arylamino groups (e.g., phenylamino group), mono- or di-aralkylamino groups (e.g., benzylamino group, dibenzylamino group), heterocyclic amino groups (e.g., pyridylamino group), and the like.

[0067] In this specification, the description of alkyl groups in alkoxy groups (i.e., alkyloxy groups) is the same as the description of alkyl groups above. The alkoxy group may have substituents. Examples of substituents include halogen atoms, hydroxyl groups, and optionally substituted amino groups.

[0068] In this specification, the description of the alkenyl group in the alkenyloxy group is the same as the description of the alkenyl group above. The alkenyloxy group may have substituents. Examples of substituents include halogen atoms, hydroxyl groups, and optionally substituted amino groups.

[0069] In this specification, the description of the alkyl group in an alkoxycarbonyl group (i.e., an alkyloxycarbonyl group) is the same as the description of the alkyl group above. The alkoxycarbonyl group may have substituents. Examples of substituents include halogen atoms, hydroxyl groups, and optionally substituted amino groups.

[0070] Examples of monodentate ligands represented by X include alkoxy anions (RO - )(In the above formula, R represents an organic group), carboxylate anion (RCOO - Examples include oxo(O), where R represents an organic group.

[0071] Alkoxy anions are RO -(In the above formula, R represents an organic group). The organic group R may be either an aliphatic group or an aromatic group. Furthermore, the aliphatic group may be either a saturated aliphatic group or an unsaturated aliphatic group. The number of carbon atoms in the organic group R is preferably 1 to 20, more preferably 6 to 18, and particularly preferably 8 to 14. Alkoxy anion (RO - Examples of these include methoxide, ethoxide, propoxide, isopropoxide, butoxide, isobutoxide, sec-butoxide, tert-butoxide, pentyl oxide, hexyl oxide, phenoxide, and 4-methylphenoxide.

[0072] Carboxylate anions are RCOO - (In the above formula, R represents an organic group). The organic group R may be either an aliphatic group or an aromatic group. Furthermore, the aliphatic group may be either a saturated aliphatic group or an unsaturated aliphatic group. The number of carbon atoms in the organic group R is preferably 1 to 20, more preferably 6 to 18, and particularly preferably 8 to 14. Carboxylate anion (RCOO - Examples of carboxylic acids include carboxylate anions corresponding to carboxylic acids such as acetic acid, propionic acid, butanoic acid, pentanoic acid, hexanoic acid, heptanoic acid, octanoic acid, octicic acid, nonanoic acid, decanoic acid, dodecanoic acid, stearic acid, oleic acid, linoleic acid, linolenic acid, arachidonic acid, eicosapentaenoic acid, docosahexaenoic acid, and benzoic acid.

[0073] The terms in brackets [ ] in the formula represent polydentate ligands. Examples of polydentate ligands include acetylacetone, 3-methyl-2,4-pentanedione, acetylacetaldehyde, 2,4-hexanedione, 2,4-heptanedione, 5-methyl-2,4-hexanedione, 5,5-dimethyl-2,4-hexanedione, benzoylacetone, benzoylacetophenone, salicylaldehyde, 1,1,1-trifluoroacetylacetone, 1,1,1,5,5,5-hexafluoroacetylacetone, 3-methoxy-2,4-pentanedione, 3-cyano-2,4-pentanedione, 3-nitro-2,4-pentanedione, 3-chloro-2,4-pentanedione, acetoacetic acid, methyl acetoacetate, ethyl acetoacetate, propyl acetoacetate, salicylic acid, methyl salicylate, malonic acid, dimethyl malonate, and diethyl malonate. When coordinated to a central metal, a polydentate ligand takes on a structure from which one or more protons have been removed.

[0074] Specific examples of metal complexes (1) in which M is aluminum include aluminum diisopropylate monosec-butyrate, aluminum trisec-butyrate, aluminum triisopropylate, aluminum triethylate, aluminum tris(acetylacetonate), aluminum bis(ethylacetoacetate)mono(acetylacetonate), aluminum tris(ethylacetoacetate), aluminum octadecenylacetoacetate diisopropylate, aluminum ethylacetoacetate diisopropylate, aluminum ethylacetoacetate di-n-butyrate, aluminum propylacetoacetate diisopropylate, aluminum n-butylacetoacetate diisopropylate, aluminum tris(ethylacetoacetate), aluminum mono(acetylacetonate)bis(ethylacetoacetate), and aluminum tris(acetylacetonate).

[0075] Specific examples of metal complexes where M is titanium (1) include tetraisopropyl titanate, tetran-butyl titanate, tetraoctyl titanate, tetratert-butyl titanate, tetrastearyl titanate, titanium tetraacetylacetonate, titanium octylene glycolate (also known as bis(2-ethylhexyloxy)bis(2-ethyl-3-oxohexyloxy)titanium(IV)), titanium diisopropoxide bis(ethylacetoacetate), Examples include allyl acetacetate triisopropoxide, titanium dinormal butoxide bis(2,4-pentanedione), titanium diisopropoxide bis(tetramethylheptanedione), titanium diisopropoxide bis(ethylacetate), titanium(IV) tetra(methylphenolate), titanium oxide bis(2,4-pentanedione), monoisopropoxytitanium triisostearate, and diisopropoxytitanium diisostearate.

[0076] Specific examples of metal complexes (1) in which M is zirconium include zirconium tetran-n-propoxide, zirconium tetran-n-butoxide, zirconium tetra(acetylacetonate), zirconium allyl acetate triisopropoxide, zirconium din-n-butoxide bis(2,4-pentanedione), zirconium diisopropoxide bis(2,4-pentanedione), zirconium diisopropoxide bis(tetramethylheptanedione), zirconium diisopropoxide bis(ethylacetoacetate), zirconium butoxide (acetylacetate) bis(ethylacetoacetate), zirconium tributoxide monoacetylacetonate, zirconium octoate, zirconium stearate, trin-n-butoxyzirconium monooctylate, and trin-n-butoxyzirconium monostearate.

[0077] In one aspect of the present invention (hereinafter referred to as "Aspect (3)"), component (B) is: M is aluminum, titanium, or zirconium. One of R1 and R3 is an alkyl group, alkoxy group, or alkenyloxy group, and the remaining one is an alkyl group. R2 is a hydrogen atom, X is an alkoxy anion or a carboxylate anion, and m is 3 or 4, n is an integer between 1 and 3, and m > n. This is a metal complex (1). In embodiment (3), M is preferably aluminum or zirconium. Furthermore, the descriptions of alkyl groups, alkoxy groups or alkenyloxy groups, alkoxy anions and carboxylate anions in embodiment (3) (preferred number of carbon atoms, examples, etc.) are as described above.

[0078] In one aspect of the present invention (hereinafter referred to as "Aspect (4)"), component (B) is at least one selected from the group consisting of specific examples of the metal complex (1) in which M is aluminum, specific examples of the metal complex (1) in which M is titanium, and specific examples of the metal complex (1) in which M is zirconium. In aspect (4), component (B) is preferably at least one selected from the group consisting of specific examples of the metal complex (1) in which M is aluminum, and specific examples of the metal complex (1) in which M is zirconium, and more preferably aluminum octadecenylacetate diisopropylate and / or zirconium triputoxide monoacetylacetonate (also known as "zirconium triputoxide monoacetylacetonate").

[0079] From the viewpoint of bending resistance, the content of component (B) in the adhesive composition is preferably 0.5% by mass or more, more preferably 1% by mass or more, preferably 15% by mass or less, and more preferably 10% by mass or less, based on 100% by mass of the nonvolatile content of the adhesive composition.

[0080] <(C) component> The adhesive composition of the present invention may further contain (C) a liquid polyolefin resin and / or liquid rubber (which may be referred to as "component (C)" herein). In the present invention, "liquid" means that the viscosity at 25°C is 5,000 Pa·s or less. In the present invention, "viscosity at 25°C" means the viscosity calculated by multiplying the kinematic viscosity at 25°C, measured by a dynamic viscoelasticity measuring device, by the density. Examples of dynamic viscoelasticity measuring devices include the rheometer manufactured by TA Instruments Corporation (product name: DISCOVERY HR-2).

[0081] With respect to component (C) of the present invention, "liquid polyolefin resin" means an olefin polymer having a viscosity of 5,000 Pa·s or less at 25°C and that cannot form a rubber elastic body by crosslinking, and "liquid rubber" means a material having a viscosity of 5,000 Pa·s or less at 25°C and that can form a rubber elastic body by crosslinking. For example, liquid polyisoprene is classified as liquid rubber because it can form a rubber elastic body by crosslinking.

[0082] The viscosity of the liquid polyolefin resin and the liquid rubber at 25°C is preferably 5 to 5,000 Pa·s, more preferably 10 to 4,000 Pa·s, and even more preferably 20 to 3,000 Pa·s, respectively.

[0083] The number-average molecular weight of the liquid polyolefin resin is preferably 500 to 40,000, more preferably 750 to 35,000, and even more preferably 1,000 to 30,000. Similarly, the number-average molecular weight of the liquid rubber is 500 to 40,000, more preferably 750 to 35,000, and even more preferably 1,000 to 30,000.

[0084] The liquid polyolefin resin and / or liquid rubber is preferably liquid polybutene. The liquid polybutene may be a homopolymer (e.g., 1-butene homopolymer, isobutene homopolymer) or a copolymer (e.g., a copolymer of 1-butene and isobutene).

[0085] Liquid polyolefin resins and / or liquid rubbers can be commercially available. Examples of commercially available liquid polyolefin resins include ENEOS's "HV-300" (liquid polybutene), ENEOS's "HV-1900" (liquid polybutene), ENEOS's "HV-50" (liquid polybutene), ENEOS's "HV-35" (liquid polybutene), Kothari's "950MW" (liquid polybutene), Kothari's "2400MW", INEOS's "H-1900" (liquid polybutene), and INEOS's "H-6000" ( Examples include liquid polybutene, INEOS's "H-18000" (liquid polybutene), NOF Corporation's "200N" (liquid polybutene), Nippon Soda Co., Ltd.'s "BI-2000" (hydrogenated polybutadiene), Nippon Soda Co., Ltd.'s "BI-3000" (hydrogenated polybutadiene), Nippon Soda Co., Ltd.'s "GI-3000" (hydrogenated polybutadiene), Mitsui Chemicals Inc.'s "Lucant LX100" (liquid olefin polymer), and Mitsui Chemicals Inc.'s "Lucant LX400" (liquid olefin polymer).

[0086] Examples of commercially available liquid rubber include Idemitsu Showa Shell's "Poly bd R-45HT" (butadiene-based liquid rubber), Idemitsu Showa Shell's "Poly bd R-15HT" (butadiene-based liquid rubber), and Idemitsu Showa Shell's "Poly "ip" (liquid polyisoprene), Nippon Soda Co., Ltd. "B-1000" (liquid polybutadiene), Nippon Soda Co., Ltd. "B-3000" (liquid polybutadiene), Nippon Soda Co., Ltd. "G-3000" (liquid polybutadiene), Kuraray Co., Ltd. "LIR-30" (liquid polyisoprene), Kuraray Co., Ltd. "LIR-390" (liquid polyisoprene), Kuraray Co., Ltd. "LIR-290" (liquid polyisoprene), Kuraray Co., Ltd. "LBR-302" (liquid polybutadiene), Kuraray Co., Ltd. "LBR-305" (liquid polybutadiene), Kuraray Co., Ltd. "LBR-361" (liquid polybutadiene), Kuraray Co., Ltd. "L-SBR-820" (liquid styrene-butadiene random copolymer), Cray Valley Co., Ltd. "Ricon154" (liquid butadiene), Cray Examples include "RICON 184" (liquid styrene-butadiene random copolymer) manufactured by VALLEY.

[0087] When component (C) is used, its content in the adhesive composition is preferably 5% by mass or more, more preferably 10% by mass or more, even more preferably 15% by mass or more, preferably 80% by mass or less, more preferably 70% by mass or less, and even more preferably 60% by mass or less, based on 100% by mass of the nonvolatile content of the adhesive composition, from the viewpoint of adhesion and bending resistance.

[0088] <Other ingredients> The adhesive composition may contain components other than components (A) to (C) (hereinafter sometimes referred to as "other components"), as long as they do not impair the effects of the present invention. Examples of other components include curing accelerators, tackifiers, inorganic or organic fillers, antioxidants, plasticizers, etc. These may be used individually or in combination of two or more.

[0089] It is preferable to use a curing accelerator as another component. Examples of curing accelerators include imidazole compounds, tertiary and quaternary amine compounds, dimethylurea compounds, and organophosphine compounds.

[0090] Examples of imidazole compounds include 1H-imidazole, 2-methylimidazole, 2-phenyl-4-methylimidazole, 2-ethyl-4-methylimidazole, 1-cyanoethyl-2-ethyl-4-methylimidazole, 2-undecylimidazole, 1-cyanoethyl-2-undecylimidazole, 1-cyanoethyl-2-undecylimidazole, 1-cyanoethyl-2-undecylimidazole, 2-phenyl-4,5-bis(hydroxymethyl)imidazole, 1-benzyl-2-methylimidazole, 1-benzyl-2-phenylimidazole, 2-phenylimidazole, 2-dodecylimidazole, 2-heptadecylimidazole, 1,2-dimethylimidazole, and 2-phenyl-4-methyl-5-hydroxymethylimidazole. Specific examples of imidazole compounds include Cureazole 2MZ, 2P4MZ, 2E4MZ, 2E4MZ-CN, C11Z, C11Z-CN, C11Z-CNS, C11Z-A, 2PHZ, 1B2MZ, 1B2PZ, 2PZ, C17Z, 1.2DMZ, 2P4MHZ-PW, 2MZ-A, and 2MA-OK (all manufactured by Shikoku Chemicals Co., Ltd.).

[0091] There are no particular restrictions on tertiary and quaternary amine compounds, but examples include quaternary ammonium salts such as tetramethylammonium bromide, tetrabutylammonium bromide, and triethylmethylammonium 2-ethylhexanoate; diazabicyclo compounds such as DBU (1,8-diazabicyclo[5.4.0]undecene-7), DBN (1,5-diazabicyclo[4.3.0]nonene-5), DBU-phenol salt, DBU-octylate, DBU-p-toluenesulfonate, DBU-formate, and DBU-phenol novolac resin salt; tertiary amines such as benzyldimethylamine, 2-(dimethylaminomethyl)phenol, and 2,4,6-tris(dimethylaminomethyl)phenol (TAP) or their salts, and dimethylurea compounds such as aromatic dimethylurea and aliphatic dimethylurea.

[0092] Examples of dimethylurea compounds include aromatic dimethylureas such as DCMU (3-(3,4-dichlorophenyl)-1,1-dimethylurea) and U-CAT3512T (manufactured by Sunapro Co., Ltd.), and aliphatic dimethylureas such as U-CAT3503N (manufactured by Sunapro Co., Ltd.). Among these, aromatic dimethylureas are preferred due to their curability.

[0093] Examples of organic phosphine compounds include triphenylphosphine, tetraphenylphosphonium tetra-p-tolylborate, tetraphenylphosphonium tetraphenylborate, tri-tert-butylphosphonium tetraphenylborate, (4-methylphenyl)triphenylphosphonium thiocyanate, tetraphenylphosphonium thiocyanate, butyltriphenylphosphonium thiocyanate, and triphenylphosphinetriphenylborane. Specific examples of organic phosphine compounds include TPP, TPP-MK, TPP-K, TTBuP-K, TPP-SCN, and TPP-S (all manufactured by Hokko Chemical Industry Co., Ltd.).

[0094] When a curing accelerator is used, its content in the adhesive composition is preferably 0.01% by mass or more, more preferably 0.05% by mass or more, even more preferably 0.1% by mass or more, preferably 2% by mass or less, more preferably 1% by mass or less, and even more preferably 0.5% by mass or less, based on 100% by mass of the nonvolatile content of the adhesive composition, in order to promote the formation of component (A) (i.e., a crosslinked isobutene polymer having a long-chain alkyl (meth)acrylate polymer chain). [Examples]

[0095] The present invention will be described in more detail below with reference to examples, but the present invention is not limited by the following examples, and it is possible to implement it with appropriate modifications within the scope that is consistent with the spirit of the above and below, and all such modifications are included in the technical scope of the present invention. In addition, unless otherwise specified, "parts" and "%" in the amounts of components and copolymer units mean "parts by mass" and "mass%", respectively.

[0096] <Ingredients> The components used in the examples and comparative examples are shown below. (1) Raw materials for component (A) or component (A') (1-1) Isobutene polymer having long-chain alkyl (meth)acrylate polymer chains and epoxy groups "ER869" (manufactured by Seikoh PMC, glycidyl methacrylate-2-ethylhexyl acrylate random copolymer modified butyl rubber (hereinafter sometimes referred to as "GMA+2-EHA modified IIR"), concentration of long-chain alkyl (meth)acrylate units: 0.067 mmol / g, epoxy group concentration: 1.51 mmol / g, number average molecular weight: 189,000, isobutene units / isoprene units: 98.9% / 1.1%) "ER872" (manufactured by Seikoh PMC, glycidyl methacrylate-lauryl methacrylate random copolymer modified butyl rubber (hereinafter sometimes referred to as "GMA+LMA modified IIR"), concentration of long-chain alkyl (meth)acrylate units: 0.067 mmol / g, epoxy group concentration: 1.51 mmol / g, number average molecular weight: 166,000, isobutene units / isoprene units: 98.9% / 1.1%)

[0097] (1-2) Isobutene polymers having long-chain alkyl (meth)acrylate polymer chains and acid anhydride groups "ER669" (manufactured by Seikoh PMC, 2-ethylhexyl maleate anhydride random copolymer modified butyl rubber (hereinafter sometimes referred to as "MA+2-EHA modified IIR"), concentration of long-chain alkyl (meth)acrylate units: 0.21 mmol / g, concentration of acid anhydride groups: 0.43 mmol / g, number average molecular weight: 96,000, isobutene units / isoprene units: 98.9% / 1.1%) "ER674" (manufactured by Seikoh PMC, maleic anhydride-lauryl methacrylate random copolymer modified butyl rubber (hereinafter sometimes referred to as "MA+LMA modified IIR"), concentration of long-chain alkyl (meth)acrylate units: 0.21 mmol / g, concentration of acid anhydride groups: 0.43 mmol / g, number average molecular weight: 142,900, isobutene units / isoprene units: 98.9% / 1.1%)

[0098] (1-3) Isobutene polymers having epoxy groups or acid anhydride groups "ER866" (manufactured by Seikoh PMC, glycidyl methacrylate-modified butyl rubber (hereinafter sometimes referred to as "GMA-modified IIR"), epoxy group concentration: 1.63 mmol / g, number average molecular weight: 113,000, isobutene units / isoprene units: 98.9% / 1.1%) "ER661" (manufactured by Seikoh PMC, maleic anhydride-butyl methacrylate random copolymer modified butyl rubber (hereinafter sometimes referred to as "MA+BMA modified IIR"), butyl methacrylate unit concentration: 0.32 mmol / g, acid anhydride group concentration: 0.32 mmol / g, number average molecular weight: 40,000, isobutene units / isoprene units: 98.9% / 1.1%)

[0099] (2)(B) Component "PlenAct AL-M" (manufactured by Ajinomoto Fine Techno Co., Ltd., an aluminum chelate compound (aluminum octadecenylacetoacetate diisopropylate)) "Orgatics ZC-540" (manufactured by Matsumoto Fine Chemical Co., Ltd., zirconium chelate compound (zirconium triputoxymonoacetylacetonate))

[0100] (3)(C) component "HV-1900" (manufactured by ENEOS Corporation, liquid polybutene, number average molecular weight: 2,900, viscosity at 25°C: 460 Pa·s)

[0101] (4) Other ingredients "U CAT18X" (manufactured by Sunapro, a curing accelerator)

[0102] <Example 1> Varnishes with the mixing ratios shown in the table below were prepared using the following procedure, and adhesive sheets were made using the obtained varnishes. The amount (parts) of each component listed in the table below indicates the amount of non-volatile content of each component in the varnish.

[0103] Specifically, glycidyl methacrylate-2-ethylhexyl acrylate random copolymer modified butyl rubber (Seiko PMC "ER869"), maleic anhydride-2-ethylhexyl acrylate random copolymer modified butyl rubber (Seiko PMC "ER669"), polybutene (ENEOS "HV-1900"), aluminum chelate compound (Ajinomoto Fine Techno "Plenact AL-M"), and curing accelerator (Sun Apro "U CAT18X") were blended, and the resulting mixture was uniformly dispersed in a high-speed rotary mixer to obtain an adhesive composition varnish. The obtained varnish was uniformly applied using a die coater to the release-treated surface of a polyethylene terephthalate (PET) film (Toyo Cloth "SP3000", PET film thickness: 38 μm) treated with a silicone-based release agent, and heated at 130°C for 30 minutes to obtain an adhesive sheet having an adhesive composition layer with a thickness of 50 μm.

[0104] <Example 2> Except for replacing the glycidyl methacrylate-2-ethylhexyl acrylate random copolymer modified butyl rubber (Seiko PMC's "ER869") with glycidyl methacrylate-lauryl methacrylate random copolymer modified butyl rubber (Seiko PMC's "ER872"), and the maleic anhydride-2-ethylhexyl acrylate random copolymer modified butyl rubber (Seiko PMC's "ER669") with maleic anhydride-lauryl methacrylate random copolymer modified butyl rubber (Seiko PMC's "ER674"). The same method as in Example 1 was used to prepare a varnish for the adhesive composition and an adhesive sheet having an adhesive composition layer with a thickness of 50 μm.

[0105] <Example 3> Except for replacing the glycidyl methacrylate-2-ethylhexyl acrylate random copolymer-modified butyl rubber (Seiko PMC's "ER869") with glycidyl methacrylate-modified butyl rubber (Seiko PMC's "ER866"), an adhesive sheet having a varnish of the adhesive composition and an adhesive composition layer with a thickness of 50 μm was prepared using the same method as in Example 1.

[0106] <Example 4> Except for replacing maleic anhydride-2-ethylhexyl acrylate random copolymer modified butyl rubber (Seiko PMC "ER669") with maleic anhydride-butyl methacrylate random copolymer modified butyl rubber (Seiko PMC "ER661"), an adhesive sheet having a varnish of the adhesive composition and an adhesive composition layer with a thickness of 50 μm was prepared using the same method as in Example 1.

[0107] <Example 5> Except for replacing the aluminum chelating compound (PlenAct AL-M, manufactured by Ajinomoto Fine Techno Co., Ltd.) with a zirconium chelating compound (OrgaTix ZC-540, manufactured by Matsumoto Fine Chemical Co., Ltd.), an adhesive sheet having a varnish for the adhesive composition and an adhesive composition layer with a thickness of 50 μm was prepared using the same method as in Example 1.

[0108] <Comparative Example 1> Except for replacing the glycidyl methacrylate-2-ethylhexyl acrylate random copolymer modified butyl rubber (Seiko PMC's "ER869") with glycidyl methacrylate modified butyl rubber (Seiko PMC's "ER866"), and replacing the maleic anhydride-2-ethylhexyl acrylate random copolymer modified butyl rubber (Seiko PMC's "ER669") with maleic anhydride-butyl methacrylate random copolymer modified butyl rubber (Seiko PMC's "ER661"). The same method as in Example 1 was used to prepare a varnish for the adhesive composition and an adhesive sheet having an adhesive composition layer with a thickness of 50 μm.

[0109] In this specification, "maleic anhydride-butyl methacrylate random copolymer-modified butyl rubber" means "butyl rubber having maleic anhydride-butyl methacrylate random copolymer chains as side chains." Furthermore, in this specification, "the crosslinked polymer in the adhesive composition layer of Comparative Example 1, formed from glycidyl methacrylate-2-ethylhexyl acrylate random copolymer-modified butyl rubber and maleic anhydride-butyl methacrylate random copolymer-modified butyl rubber" is described as "(A') component," "constituent units derived from butyl methacrylate" is described as "butyl methacrylate units," and "polymer chains containing butyl methacrylate units" is described as "butyl methacrylate polymer chains."

[0110] <Comparative Example 2> Except for not using an aluminum chelate compound (PlenAct AL-M, manufactured by Ajinomoto Fine Techno Co., Ltd.), an adhesive sheet having a varnish for the adhesive composition and an adhesive composition layer with a thickness of 50 μm was prepared using the same method as in Example 1.

[0111] <Method for evaluating adhesiveness> Adhesive sheets using PET film as a support were cut to a length of 50 mm and a width of 20 mm. The adhesive composition layer of the cut adhesive sheets was then laminated to the PET surface of a composite film (PET-Tsuki AL1N30, manufactured by Tokai Toyo Aluminum Sales Co., Ltd., aluminum foil thickness: 30 μm, PET film thickness: 25 μm) using a batch-type vacuum laminator ("Morton-724," manufactured by Nichigo Morton Co., Ltd.) to prepare a laminate having a layered structure of "composite film / adhesive composition layer / support (PET film)." Lamination was performed under conditions of a temperature of 80°C, a time of 30 seconds, and a pressure of 0.3 MPa. From the obtained laminate, the support (PET film) was peeled off, and a polyimide film (Ube Industries, Ltd.'s "UPIREX-S", thickness: 50 μm) was laminated onto the exposed adhesive composition layer under the same conditions as above to obtain a laminate having a laminated structure of "composite film / adhesive composition layer / polyimide film". For the obtained laminate, the adhesive strength (room temperature adhesive strength) was measured when the "composite film / adhesive composition layer" was peeled off from the polyimide film at room temperature, with a tensile speed of 300 mm / min in the direction 180 degrees to the longitudinal direction of the PET film of the composite film. In addition, the adhesive strength (high temperature adhesive strength) was measured when the laminate prepared in the same manner as above was peeled off in the same manner under conditions of 60°C. The results are shown in Table 1.

[0112] The adhesive properties of the adhesive composition at high temperatures were evaluated according to the following criteria. (Adhesion at high temperatures) ◎(Excellent): High-temperature adhesive strength of 0.60 kgf / cm or higher ○ (Good): High-temperature adhesive strength is 0.55 kgf / cm or more and less than 0.60 kgf / cm. × (Defective): High-temperature adhesive strength is less than 0.55 kgf / cm

[0113] <Method for evaluating bending resistance> An evaluation sample with a thickness of approximately 1.0 mm and a diameter of 8 mm was prepared by folding an adhesive sheet and punching out the folded sheet with an 8 mm diameter belt punch. The evaluation sample was placed on a DHR parallel plate rheometer, and the shear strain rate S1 of the evaluation sample was measured after applying a shear stress of 95 kPa for 5 seconds. Subsequently, the shear strain rate S2 of the evaluation sample was measured 60 seconds after the applied stress was released.

[0114] From the shear strain rate S1 of the evaluation sample after applying a shear stress of 95 kPa for 5 seconds, and the shear strain rate S2 of the evaluation sample 60 seconds after the applied stress is released, the following formula is used: Strain recovery rate (%) = 100 × (S1 - S2) / S1 The strain recovery rate was calculated using this method.

[0115] Laminates containing an adhesive composition layer with a good strain recovery rate can prevent peeling and lifting even when bent. Therefore, the bending resistance was evaluated using the strain recovery rate according to the following criteria. The results are shown in Table 1. (flexure resistance) ◎ (Excellent): Strain recovery rate of 95% or higher ○ (Good): Strain recovery rate is 90% or higher, but less than 95%. × (Defective): Strain recovery rate is less than 90%

[0116] [Table 1]

[0117] The adhesive compositions of Examples 1 to 5, which contained a crosslinked isobutene polymer having long-chain alkyl (meth)acrylate polymer chains (component (A)) and an aluminum or zirconium chelate compound (component (B)), exhibited excellent adhesion at high temperatures (high-temperature adhesive strength) and bending resistance (strain recovery rate).

[0118] On the other hand, the adhesive composition of Comparative Example 1, which contained component (A') having a butyl methacrylate polymer chain instead of component (A), exhibited poor adhesion at high temperatures. Furthermore, the adhesive composition of Comparative Example 2, which did not contain component (B), exhibited poor bending resistance. [Industrial applicability]

[0119] The adhesive composition and adhesive sheet of the present invention are useful for the manufacture of flexible electronic devices (particularly for the manufacture of laminates that constitute flexible devices).

[0120] This application is based on Japanese Patent Application No. 2020-204467, which is fully contained herein.

Claims

1. (A) Isobutene polymers having a crosslinked structure formed by the reaction of epoxy groups with acid anhydride groups and / or carboxyl groups, and (B) Chelate compounds with a divalent or higher metal as the central metal An adhesive composition comprising, The component (A) is a reaction product of an isobutene-isoprene copolymer having a polymer chain as a side chain containing an epoxy group and a structural unit derived from an alkyl (meth)acrylate having an alkyl group having 6 or more carbon atoms, and an isobutene-isoprene copolymer having a polymer chain as a side chain containing an acid anhydride group and / or a carboxyl group and a structural unit derived from an alkyl (meth)acrylate having an alkyl group having 6 or more carbon atoms. The aforementioned component (B) is given by the following formula (1): 【Chemistry 1】 [In formula (1), M represents a metal with a valent or higher valency. R １ and R ３ Each of these independently represents a hydrogen atom, an alkyl group, an alkenyl group, an alkynyl group, an alkoxy group, an alkenyloxy group, an aryl group, or an aralkyl group. R ２ This represents a hydrogen atom, alkyl group, alkenyl group, alkynyl group, alkoxy group, alkenyloxy group, alkoxycarbonyl group, aryl group, or aralkyl group. X represents a single-seat ligand, In equation (1), the solid line between the oxygen atom (O) and M in the brackets [ ] represents a covalent bond. In formula (1), the dashed line between the oxygen atom (O) and M in the brackets [ ] represents a coordinate covalent bond, and m represents 3 or 4, and n represents an integer between 0 and 4, where m ≥ n. A metal complex represented by, The adhesive composition further comprises (C) a liquid polyolefin resin and / or liquid rubber. Adhesive composition.

2. The adhesive composition according to claim 1, wherein the concentration of constituent units derived from alkyl (meth)acrylate having an alkyl group having 6 or more carbon atoms in the isobutene polymer is 0.005 to 5 mmol / g.

3. The adhesive composition according to claim 1, wherein the metal with a valency of 2 or higher is a metal of Group 4 of the periodic table or a metal of Group 13 of the periodic table.

4. The adhesive composition according to claim 1, wherein the divalent or higher metal is aluminum, titanium, or zirconium.

5. M is aluminum, titanium, or zirconium. R １ and R ３ One of them is an alkyl group, alkoxy group, or alkenyloxy group, and the other one is an alkyl group. R ２ However, it is a hydrogen atom, X is an alkoxide anion or a carboxylate anion, and m is 3 or 4, n is an integer between 1 and 3, and m > n. The adhesive composition according to claim 1.

6. The adhesive composition according to claim 1 or 5, wherein M is aluminum or zirconium.

7. An adhesive sheet having a laminated structure comprising an adhesive composition layer formed from the adhesive composition according to any one of claims 1 to 6, and a support.

8. An adhesive sheet according to claim 7, used in the manufacture of a flexible electronic device.

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