Adhesive composition, bonding film, laminate with adhesive layer, and laminate

Abstract

This adhesive composition (100) contains: a base material resin (A) which contains at least one resin that is selected from the group consisting of a polyamide resin and a polyurethane resin; an epoxy compound (B) in an amount of 1 part by mass to 50 parts by mass inclusive relative to 100 parts by mass of the base material resin (A); a triazine compound (C) in an amount of 10 parts by mass to 70 parts by mass inclusive relative to 100 parts by mass of the base material resin (A); and a metal phosphinate (D) in an amount of 0.5 part by mass to 50 parts by mass inclusive relative to 100 parts by mass of the base material resin (A). The triazine compound (C) contains a specific structure in the molecular structure thereof.

Description

Adhesive composition, bonding film, laminate with adhesive layer, and laminate

[0001] The present invention relates to an adhesive composition, a bonding film, a laminate with an adhesive layer, and a laminate.

[0002] Flexible printed circuit boards (hereinafter referred to as "FPCs") are capable of three-dimensional, high-density mounting even in limited spaces, and their applications are expanding. In recent years, as electronic devices have become smaller and lighter, FPC-related products have become more diverse and demand for them has increased.

[0003] Examples of such FPC-related products include flexible copper-clad laminates made by bonding a polyimide film and copper foil together, flexible printed wiring boards in which an electronic circuit is formed on a flexible copper-clad laminate, flexible printed wiring boards with reinforcement plates made by bonding a flexible printed wiring board and a reinforcement plate together, multilayer boards made by stacking and bonding flexible copper-clad laminates or flexible printed wiring boards, and flexible flat cables (hereinafter also referred to as "FFCs") in which copper wiring is bonded to a base film, and adhesives are usually used in the production of these products.

[0004] Furthermore, when manufacturing FPCs and FPC-related products, a laminate with an adhesive layer called a "coverlay film" is sometimes used to protect the wiring portion. The coverlay film comprises an insulating base film and an adhesive layer formed on the surface of the insulating base film, and polyimide resin is widely used as the material for the base film. Then, for example, a flexible printed wiring board is manufactured by attaching the coverlay film via the adhesive layer to the surface having the wiring portion using a heat press or the like.

[0005] Also known as printed wiring boards are build-up multilayer printed wiring boards in which conductor layers and organic insulating layers are alternately laminated on the surface of a substrate. An insulating adhesive layer is interposed between the conductor layer and the organic insulating layer in the multilayer printed wiring board, and the conductor layer and the organic insulating layer are bonded via the insulating adhesive layer. A sheet made of an uncured or semi-cured adhesive called a "bonding film" is used to form the insulating adhesive layer.

[0006] As an adhesive composition used for FPCs and FPC-related products, for example, Patent Document 1 describes an adhesive composition containing (A) a thermoplastic resin, (B) a phosphorus-containing phenoxy resin, (C) a phosphorus-containing epoxy resin, and (D) a curing agent. Furthermore, this type of adhesive composition may contain a phosphorus compound such as triphenyl phosphate as a flame retardant.

[0007] Japanese Patent Application Laid-Open No. 2003-298230

[0008] However, the cured product of the adhesive composition of Patent Document 1 has a problem in that it is prone to lose heat resistance when it absorbs moisture.

[0009] The present invention has been made in view of the above problems, and aims to provide an adhesive composition that can form a cured product that exhibits excellent heat resistance even in a hygroscopic state, and a bonding film, a laminate with an adhesive layer, and a laminate that use this adhesive composition.

[0010] A first aspect of the present invention resides in an adhesive composition according to the following items [1] to [6]: [1] An adhesive composition comprising: a base resin (A) containing at least one resin selected from the group consisting of polyamide-based resins and polyurethane-based resins; an epoxy compound (B) in an amount of 1 part by mass to 50 parts by mass per 100 parts by mass of the base resin (A); a triazine-based compound (C) in an amount of 10 parts by mass to 70 parts by mass per 100 parts by mass of the base resin (A); and a metal phosphinate (D) in an amount of 0.5 parts by mass to 50 parts by mass per 100 parts by mass of the base resin (A), wherein the triazine-based compound (C) contains, in its molecular structure, one or more structures selected from the group consisting of a structure represented by the following general formula (C1) and a structure represented by the following structural formula (C2):

[0011]

[0012] However, R in the general formula (C1) 1 ~R 3 each independently represents an amino group, a hydroxy group, a thiol group, a methyl group, or a phenyl group.

[0013]

[0014] [2] The adhesive composition according to [1], wherein the triazine compound (C) contains a structure represented by the following structural formula (C3) in its molecular structure:

[0015]

[0016] [3] The adhesive composition according to [1] or [2], wherein the triazine compound (C) has a volume-based median diameter of 10 μm or less. [4] The adhesive composition according to any one of [1] to [3], wherein the base resin (A) contains a polyester polyamide as a polyamide-based resin. [5] The adhesive composition according to any one of [1] to [4], wherein the base resin (A) contains a polyester polyurethane as a polyurethane-based resin. [6] The adhesive composition according to any one of [1] to [5], wherein the base resin (A) contains a polyurethane-based resin having a polyphenylene ether skeleton containing a plurality of phenylene groups and ether bonds bonding the phenylene groups together.

[0017] A second aspect of the present invention is a bonding film according to the following item [7]: [7] A bonding film having an adhesive layer and a release film provided on one or both sides of the adhesive layer and configured to be peelable from the adhesive layer, wherein the adhesive layer is composed of the adhesive composition according to any one of items [1] to [6] or a semi-cured product obtained by partially curing the adhesive composition.

[0018] A third aspect of the present invention resides in a laminate with an adhesive layer according to the following item [8]: [8] A laminate with an adhesive layer, comprising an adhesive layer and a base layer adhered to at least one surface of the adhesive layer, wherein the adhesive layer is composed of the adhesive composition according to any one of items [1] to [6] or a semi-cured product obtained by partially curing the adhesive composition.

[0019] A fourth aspect of the present invention is a laminate according to the following item [9]: [9] A laminate comprising a cured product layer made of a cured product of the adhesive composition according to any one of items [1] to [6].

[0020] The adhesive composition contains the base resin (A), the epoxy compound (B), the triazine compound (C), and the metal phosphinate (D) in the specific ratios described above. A cured product of the adhesive composition having such a composition has good heat resistance even when it absorbs moisture.

[0021] Furthermore, both the bonding film and the laminate with an adhesive layer have an adhesive layer made of the adhesive composition or a semi-cured product thereof. Therefore, by producing a laminate using these materials, the adhesive state of each layer constituting the laminate can be maintained even when the laminate in a moisture-absorbed state is heated.

[0022] Furthermore, the laminate has a cured product layer made of the cured product of the adhesive composition, and therefore, even when the laminate is heated in a moisture-absorbed state, the adhesive state of each layer constituting the laminate can be maintained.

[0023] As described above, according to the above-described aspects, it is possible to provide an adhesive composition capable of forming a cured product that exhibits excellent heat resistance even in a hygroscopic state, and a bonding film, a laminate with an adhesive layer, and a laminate each using this adhesive composition.

[0024] Fig. 1 is a partial cross-sectional view of a test piece A for evaluating flame retardancy in an example. Fig. 2 is a partial cross-sectional view of a bonding film B in an example. Fig. 3 is a partial cross-sectional view of a test piece C for evaluating adhesion in an example.

[0025] (Adhesive Composition) [Base Resin (A)] The adhesive composition contains, as the base resin (A), at least one resin selected from the group consisting of polyamide-based resins and polyurethane-based resins. In this specification, a polyamide-based resin refers to a resin containing an amide moiety formed by bonding multiple repeating units via amide bonds. That is, the polyamide-based resin may be, for example, a polyamide in which one or more types of repeating units are bonded via amide bonds. Furthermore, the polyamide-based resin may be, for example, a resin containing an amide bond and a bonding group other than an amide bond as the bonding group bonding the repeating units. Examples of such resins include polyester polyamides containing an amide bond and an ester bond as the bonding group. The polyamide-based resin may have a linear molecular structure or a molecular structure containing a branched chain.

[0026] In this specification, a polyurethane-based resin refers to a resin containing a polyurethane moiety in which multiple repeating units are bonded via urethane bonds. That is, the polyurethane-based resin may be, for example, a polyurethane in which one or more types of repeating units are bonded via urethane bonds. The polyurethane-based resin may also be, for example, a resin containing a urethane bond and a bonding group other than a urethane bond as the bonding group bonding the repeating units. Examples of such resins include polyester polyurethanes containing a urethane bond and an ester bond as the bonding group. The polyurethane-based resin may have a linear molecular structure or a molecular structure containing a branched chain. Furthermore, the polyurethane-based resin may have a polyphenylene ether skeleton containing multiple phenylene groups and ether bonds bonding the phenylene groups.

[0027] From the viewpoint of more reliably improving the heat resistance of the cured product in a hygroscopic state, it is preferable that the base resin (A) contains one or more resins selected from the group consisting of polyester polyamides, polyester polyurethanes, and the polyurethane-based resins having a polyphenylene ether skeleton. From the same viewpoint, it is more preferable that the base resin (A) is any one resin selected from the group consisting of polyester polyamides, polyester polyurethanes, and the polyurethane-based resins having a polyphenylene ether skeleton.

[0028] The weight-average molecular weight of the base resin (A) is preferably 5,000 or more and 150,000 or less. In this case, the heat resistance of the cured product in a moisture-absorbed state can be more reliably improved. From the same viewpoint, the number-average molecular weight of the base resin (A) is preferably 1,500 or more and 100,000 or less. The values ​​of the number-average molecular weight and weight-average molecular weight of the base resin (A) are polystyrene-equivalent values ​​obtained by gel permeation chromatography (hereinafter also referred to as "GPC") using polystyrene as a standard substance.

[0029] Specific measurement conditions for GPC are, for example, as follows: Apparatus: "HLC-8320" manufactured by Tosoh Corporation Column: "TSKgel SuperMultiporeHZ-M" manufactured by Tosoh Corporation x 4 Solvent: Tetrahydrofuran Column temperature: 40°C Detector: RI Flow rate: 600 μL / min

[0030] From the viewpoints of adhesion and heat resistance, the content of the base resin (A) in the adhesive composition is preferably from 5% by mass to 90% by mass, more preferably from 10% by mass to 80% by mass, even more preferably from 20% by mass to 75% by mass, and particularly preferably from 30% by mass to 70% by mass, relative to the total solid content of the adhesive composition.

[0031] The polyamide-based resin used in the base resin (A) may be a polyamide. The adhesive composition may contain one type of polyamide, or two or more types of polyamide.

[0032] The polyamide has a repeating unit derived from a polycarboxylic acid having two or more carboxy groups, a repeating unit derived from an amine having two or more amino groups, and an amide bond connecting these. The polyamide may have a linear molecular structure or a molecular structure including a branched chain. From the viewpoint of improving processability in heat press processing or heat lamination processing, the polyamide preferably has a linear molecular structure. From the same viewpoint, the polyamide preferably does not have an aromatic ring in its molecular structure.

[0033] The polyamide preferably has a repeating unit derived from a dicarboxylic acid and a repeating unit derived from a diamine, and may also have a repeating unit having a carboxy group and a functional group other than a carboxy group, such as a hydroxycarboxylic acid or a sulfocarboxylic acid.

[0034] Examples of dicarboxylic acids used in polyamides include chain aliphatic dicarboxylic acids, alicyclic dicarboxylic acids, and aromatic dicarboxylic acids. Examples of chain aliphatic carboxylic acids used in polyamides include succinic acid, adipic acid, azelaic acid, sebacic acid, dodecanedioic acid, and dimer acid. From the viewpoint of more reliably improving the heat resistance of a cured product in a moisture-absorbed state, the polyamide preferably contains repeating units derived from one or two chain aliphatic dicarboxylic acids selected from azelaic acid and a dimer acid, and more preferably contains repeating units derived from azelaic acid.

[0035] Examples of the alicyclic dicarboxylic acid used in the polyamide include 1,4-cyclohexanedicarboxylic acid, 1,3-cyclohexanedicarboxylic acid, 1,2-cyclohexanedicarboxylic acid, and anhydrides of 1,2-cyclohexanedicarboxylic acid.

[0036] Examples of aromatic dicarboxylic acids used in polyamides include aromatic dicarboxylic acids that do not have a sulfonic acid group or a sulfonate salt group, such as terephthalic acid, isophthalic acid, orthophthalic acid, naphthalenedicarboxylic acid, biphenyldicarboxylic acid, and 5-hydroxyisophthalic acid; aromatic sulfodicarboxylic acids such as sulfoterephthalic acid, 5-sulfoisophthalic acid, 4-sulfophthalic acid, 4-sulfonaphthalene-2,7-dicarboxylic acid, and 5-(4-sulfophenoxy)isophthalic acid; metal salts of aromatic sulfodicarboxylic acids; and ammonium salts of aromatic sulfodicarboxylic acids.

[0037] The polyamide preferably contains repeating units derived from one or more dicarboxylic acids selected from the group consisting of open-chain aliphatic dicarboxylic acids having from 6 to 22 carbon atoms (excluding dimerized aliphatic diacids), aromatic dicarboxylic acids having from 6 to 22 carbon atoms, alicyclic dicarboxylic acids having from 6 to 22 carbon atoms (excluding dimerized aliphatic diacids), and dimerized aliphatic diacids having from 20 to 48 carbon atoms. More specifically, the polyamide may contain repeating units derived from one or more dicarboxylic acids selected from the group consisting of open-chain aliphatic dicarboxylic acids, aromatic dicarboxylic acids, and alicyclic dicarboxylic acids, and repeating units derived from the dimerized aliphatic diacids, or may contain repeating units derived from one or more dicarboxylic acids selected from the group consisting of open-chain aliphatic dicarboxylic acids, aromatic dicarboxylic acids, and alicyclic dicarboxylic acids, and may contain repeating units derived from the dimerized aliphatic diacids.

[0038] From the viewpoint of further improving the heat resistance of the cured product in a moisture-absorbed state, the polyamide more preferably contains a repeating unit derived from one or more dicarboxylic acids selected from the group consisting of the chain aliphatic dicarboxylic acids, the alicyclic dicarboxylic acids, and the dimerized aliphatic diacids, and even more preferably contains a repeating unit derived from azelaic acid. Furthermore, the number of carbon atoms in the chain aliphatic dicarboxylic acids, aromatic dicarboxylic acids, and alicyclic dicarboxylic acids contained in the polyamide is preferably 6 to 12, more preferably 8 to 10. The number of carbon atoms in the dimerized aliphatic diacid contained in the polyamide moiety is preferably 30 to 48, more preferably 32 to 40.

[0039] Examples of polyamines used in polyamides include diamines and aminocarboxylic acids. Examples of diamines used in polyamides include diaminocyclohexane, piperidine, isophoronediamine, 1,2-diaminoethane, 1,3-diaminopropane, 1,4-diaminobutane, 1,5-diaminopentane, 1,6-diaminohexane, 1,7-diaminoheptane, 1,8-diaminooctane, 1,9-diaminononane, o-(or m-, p-)phenylenediamine, o-(or m-, p-)xylenediamine, 3,3'-(or 3,4'-)diaminodiphenylene ether, 4,4'-diaminodiphenyl ether, 3,3'-(or 3,4'-)diaminodiphenylmethane, 4,4'-diaminodiphenylmethane, 3,3'-(or 3,4'-, 4,4'-)diaminodiphenyldifluoromethane, 3,3'-(or 3,4'-, 4,4'-)diaminodiphenyl sulfone, 3,3'-(or 3,4'-, 4,4'-)diaminodiphenyl sulfide, 3,3'-(or 3,4'-, 4,4'-)diaminodiphenyl ketone, 2,2-bis (3-aminophenyl)propane, 2,2'-(3,4'-diaminodiphenyl)propane, 2,2-bis(4-aminophenyl)propane, 2,2-bis(3-aminophenyl)hexafluoropropane, 2,2-(3,4'-diaminodiphenyl)hexafluoropropane, 2,2-bis(4-aminophenyl)hexafluoropropane, 1,3-(or 1,4-)bis(3-aminophenoxy)benzene, 1,4-bis(4-aminophenoxy)benzene, 3,3'-( 1-phenylenebis(1-methylethylidene))bisaniline, 3,4'-(1,4-phenylenebis(1-methylethylidene))bisaniline, 4,4'-(1,4-phenylenebis(1-methylethylidene))bisaniline, 2,2-bis(4-(3-aminophenoxy)phenyl)propane, 2,2-bis(4-(4-aminophenoxy)phenyl)propane, and 2,2-bis(4-(4-aminophenoxy)phenyl)hexafluoropropane.

[0040] From the viewpoint of further improving the heat resistance of the cured product in a moisture-absorbing state, the polyamide preferably contains one or more repeating units selected from the group consisting of aromatic diamines having from 6 to 44 carbon atoms and diamines having an alicyclic skeleton having from 6 to 44 carbon atoms, more preferably contains repeating units derived from diamines having an alicyclic skeleton having from 6 to 44 carbon atoms, and particularly preferably contains isophoronediamine. The diamine preferably has from 8 to 30 carbon atoms, more preferably from 10 to 24 carbon atoms.

[0041] From a similar viewpoint, the polyamide preferably contains repeating units derived from one or more dicarboxylic acids selected from the group consisting of chain aliphatic dicarboxylic acids having from 6 to 22 carbon atoms (excluding dimeric aliphatic diacids), aromatic dicarboxylic acids having from 6 to 22 carbon atoms, alicyclic dicarboxylic acids having from 6 to 22 carbon atoms (excluding dimeric aliphatic diacids), and dimeric aliphatic diacids having from 20 to 48 carbon atoms, and repeating units derived from one or more diamines selected from the group consisting of aromatic diamines having from 6 to 44 carbon atoms and diamines having an alicyclic skeleton having from 6 to 44 carbon atoms. It is more preferable that the polyamide contains repeating units derived from one or more dicarboxylic acids selected from the group consisting of chain aliphatic dicarboxylic acids, alicyclic dicarboxylic acids, and dimeric aliphatic diacids, and repeating units derived from the diamines having an alicyclic skeleton.

[0042] The polyamide may also have a repeating unit derived from a polycarboxylic acid having three or more carboxy groups. In this case, a branched chain can be introduced into the polyamide. Furthermore, by introducing a branched chain into the polyamide, the terminal group concentration (i.e., the number of reaction sites) of the resin can be increased. Therefore, for example, by reacting a branched polyamide with a curing agent, a cured layer with a high crosslink density can be obtained.

[0043] The content of repeating units derived from polycarboxylic acids having three or more carboxy groups is preferably 0.1 mol % or more and 5 mol % or less, and more preferably 0.1 mol % or more and 3 mol % or less, based on all repeating units in the polyamide.

[0044] Examples of polycarboxylic acids having three or more carboxy groups include trimellitic acid, trimesic acid, ethylene glycol bis(anhydrotrimellitate), glycerol tris(anhydrotrimellitate), trimellitic anhydride, pyromellitic anhydride (PMDA), oxydiphthalic dianhydride (ODPA), 3,3',4,4'-benzophenonetetracarboxylic dianhydride (BTDA), 3,3',4,4'-diphenyltetracarboxylic dianhydride (BPDA), 3,3',4,4'-diphenylsulfonetetracarboxylic dianhydride (DSDA), 4,4'-(hexafluoroisopropylidene)diphthalic dianhydride (6FDA), and 2,2'-bis[(dicarboxyphenoxy)phenyl]propane dianhydride (BSAA).

[0045] The method for producing the polyamide is not particularly limited, and any known method can be used. For example, the polycarboxylic acid, polyamine, and other compounds used as needed may all be placed in a reaction vessel and then reacted, or raw materials such as the polycarboxylic acid may be placed in the reaction vessel in stages as the reaction progresses.

[0046] The polycondensation reaction of polycarboxylic acid and polyamine may be carried out in the presence of a solvent, or may be carried out without using a solvent. Examples of the solvent include ester solvents such as ethyl acetate, butyl acetate, and ethyl butyrate; ether solvents such as dioxane, tetrahydrofuran, and diethyl ether; ketone solvents such as cyclohexanone, methyl ethyl ketone, and methyl isobutyl ketone; aromatic hydrocarbon solvents such as benzene, toluene, and xylene, and mixed solvents thereof. From the viewpoint of reducing environmental load, it is preferable to use ethyl acetate or methyl ethyl ketone as the solvent. As a reaction apparatus for carrying out the polycondensation reaction, a reaction vessel equipped with a stirrer, or a mixing and kneading apparatus such as a kneader or a twin-screw extruder can be used.

[0047] In producing the polyamide, a catalyst used to promote the amidation reaction, such as tetrabutoxy titanate, can be used as needed to promote the amidation reaction. In addition, in producing the polyamide, a condensing agent or the like can also be used as needed.

[0048] Polyester Polyamide The polyamide resin used in the base resin (A) may be a polyester polyamide. The adhesive composition may contain one type of polyester polyamide, or two or more types of polyester polyamide.

[0049] The polyester polyamide has a polyester portion formed by bonding multiple repeating units via ester bonds and an amide portion formed by bonding multiple repeating units via amide bonds. The polyester portion may have two or more ester bonds. The polyamide portion may have two or more amide bonds. The polyester portion and the polyamide portion may be bonded via an ester bond or via an amide bond.

[0050] The polyester polyamide is preferably a resin having a polyester chain and two or more amide bonds, a resin having a polyamide chain and two or more ester bonds, or a resin having a polyester chain and a polyamide chain. The weight-average molecular weight of the polyester chain may be 1,000 or more. The weight-average molecular weight of the polyamide chain may be 1,000 or more. The upper limit of the weight-average molecular weight of each of the polyester chain and the polyamide chain is not particularly limited, but may be, for example, 150,000 or less.

[0051] The polyester polyamide may have a linear molecular structure or a molecular structure containing a branched chain. From the viewpoint of improving processability in hot press processing or hot lamination processing, the polyester polyamide preferably has a linear molecular structure. From the same viewpoint, the polyester polyamide preferably does not have an aromatic ring in its molecular structure.

[0052] The polyester polyamide has, for example, a repeating unit derived from a polycarboxylic acid, a repeating unit derived from a polyol, and a repeating unit derived from a polyamine. The polyester polyamide preferably has a repeating unit derived from a dicarboxylic acid, a repeating unit derived from a diol, and a repeating unit derived from a diamine.

[0053] More specifically, the polyester portion of the polyester polyamide has a repeating unit derived from a polycarboxylic acid and a repeating unit derived from a polyol. Examples of the polycarboxylic acid used in the polyester portion include the same dicarboxylic acids as those used in the polyamides described above, polycarboxylic acids having three or more carboxy groups, hydroxycarboxylic acids, and sulfocarboxylic acids. From the viewpoint of further improving the heat resistance of the cured product in a moisture-absorbed state, the polyester portion of the polyester polyamide preferably contains a repeating unit derived from one or more dicarboxylic acids selected from the group consisting of a chain aliphatic dicarboxylic acid having from 6 to 22 carbon atoms, an aromatic dicarboxylic acid having from 6 to 22 carbon atoms, and an alicyclic dicarboxylic acid having from 6 to 22 carbon atoms, and more preferably contains a repeating unit derived from a chain aliphatic dicarboxylic acid having from 6 to 22 carbon atoms and an alicyclic dicarboxylic acid having from 6 to 22 carbon atoms.

[0054] The polyol used in the polyester portion may be a diol or a polyol having three or more hydroxy groups. Examples of diols include chain aliphatic diols, alicyclic diols, aromatic diols, and ether bond-containing diols. From the viewpoint of soldering heat resistance and adhesiveness, the polyester polyamide preferably contains repeating units derived from one or more diols selected from the group consisting of chain aliphatic diols having 2 to 54 carbon atoms, aromatic diols having 2 to 54 carbon atoms, and alicyclic diols having 2 to 54 carbon atoms. More preferably, the polyester polyamide contains any one of repeating units derived from a chain aliphatic diols having 2 to 54 carbon atoms, repeating units derived from an aromatic diol having 2 to 54 carbon atoms, or repeating units derived from an alicyclic diol having 2 to 54 carbon atoms.

[0055] Examples of the chain aliphatic diol include ethylene glycol, 1,2-propylene diol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, neopentyl glycol, 1,6-hexanediol, 3-methyl-1,5-pentanediol, 1,9-nonanediol, 2-butyl-2-ethyl-1,3-propanediol, hydroxypivalic acid neopentyl glycol ester, dimethylol heptane, and 2,2,4-trimethyl-1,3-pentanediol.

[0056] Examples of alicyclic diols include 1,4-cyclohexanediol, 1,4-cyclohexanedimethanol, tricyclodecanediol, tricyclodecanedimethylol, spiroglycol, hydrogenated bisphenol A, ethylene oxide adducts of hydrogenated bisphenol A, and propylene oxide adducts of hydrogenated bisphenol A.

[0057] Examples of aromatic diols include benzenedimethanols such as 1,2-benzenedimethanol, 1,3-benzenedimethanol, and 1,4-benzenedimethanol; 2-(4-hydroxyphenyl)ethanol; bisphenols such as bisphenol A; ethylene oxide adducts of bisphenols; and propylene oxide adducts of bisphenols.

[0058] Examples of the ether bond-containing diol include diethylene glycol, triethylene glycol, dipropylene glycol, polyethylene glycol, polypropylene glycol, polytetramethylene glycol, neopentyl glycol ethylene oxide adduct, and neopentyl glycol propylene oxide adduct.

[0059] From the viewpoints of compatibility with the epoxy compound (B) and the like and solution stability, the polyester moiety preferably contains a repeating unit derived from a diol having a side chain. The side chain of the diol is preferably an alkyl group, more preferably an alkyl group having 1 to 5 carbon atoms. Examples of diols having a side chain include neopentyl glycol, 2-butyl-2-ethyl-1,3-propanediol, and 2,2-dimethylolpropionic acid.

[0060] From the viewpoints of solder heat resistance and adhesiveness, the polyester portion of the polyester polyamide preferably contains a repeating unit derived from one or more diols selected from the group consisting of a chain aliphatic diol having from 2 to 54 carbon atoms, an aromatic diol having from 2 to 54 carbon atoms, and an alicyclic diol having from 2 to 54 carbon atoms, and more preferably contains any one of a repeating unit derived from a chain aliphatic diol having from 2 to 54 carbon atoms, a repeating unit derived from an aromatic diol having from 2 to 54 carbon atoms, or a repeating unit derived from an alicyclic diol having from 2 to 54 carbon atoms.

[0061] The polyester portion of the polyester polyamide may have repeating units derived from a polycarboxylic acid having three or more carboxy groups and / or repeating units derived from a polyol having three or more hydroxy groups. In this case, a branched chain can be introduced into the polyester portion. Furthermore, by introducing a branched chain into the polyester portion, the terminal group concentration (i.e., the number of reaction sites) of the resin can be increased. Therefore, for example, by reacting a polyester polyamide having a branched chain introduced therein with a curing agent, a cured layer with a high crosslink density can be obtained.

[0062] Examples of polycarboxylic acids having three or more carboxy groups include the polycarboxylic acids having three or more carboxy groups used in the polyamides described above.

[0063] Examples of polyols having three or more hydroxy groups include glycerin, trimethylolethane, trimethylolpropane, and pentaerythritol.

[0064] The total content of repeating units derived from polycarboxylic acids having three or more carboxy groups and repeating units derived from polyols having three or more hydroxy groups is preferably 0.1 mol % or more and 5 mol % or less, and more preferably 0.1 mol % or more and 3 mol % or less, based on all repeating units in the polyester moiety.

[0065] More specifically, the polyamide portion of the polyester polyamide has a repeating unit derived from a polycarboxylic acid and a repeating unit derived from a polyamine. The polyamide portion of the polyester polyamide preferably has a repeating unit derived from a dicarboxylic acid and a repeating unit derived from a diamine. The polyamide portion may also have a repeating unit having a carboxy group and a functional group other than a carboxy group, such as a hydroxycarboxylic acid or a sulfocarboxylic acid.

[0066] Examples of polycarboxylic acids used in the polyamide portion include dicarboxylic acids similar to those used in the polyamides described above, polycarboxylic acids having three or more carboxy groups, hydroxycarboxylic acids, sulfocarboxylic acids, etc. From the viewpoint of further improving solder heat resistance and adhesiveness, it is preferable that the polyamide portion contains repeating units derived from one or more dicarboxylic acids selected from the group consisting of chain aliphatic dicarboxylic acids having 6 to 22 carbon atoms (excluding dimerized aliphatic diacids), aromatic dicarboxylic acids having 6 to 22 carbon atoms, alicyclic dicarboxylic acids having 6 to 22 carbon atoms (excluding dimerized aliphatic diacids), and dimerized aliphatic diacids having 20 to 48 carbon atoms. More specifically, the polyamide portion may contain repeating units derived from one or more dicarboxylic acids selected from the group consisting of the chain aliphatic dicarboxylic acids, the aromatic dicarboxylic acids, and the alicyclic dicarboxylic acids, and repeating units derived from the dimerized aliphatic diacids, or may contain repeating units derived from one or more dicarboxylic acids selected from the group consisting of the chain aliphatic dicarboxylic acids, the aromatic dicarboxylic acids, and the alicyclic dicarboxylic acids, and may contain repeating units derived from the dimerized aliphatic diacids.

[0067] From the viewpoint of further improving solder heat resistance and adhesiveness, the polyamide portion preferably contains a repeating unit derived from one or more dicarboxylic acids selected from the group consisting of the chain aliphatic dicarboxylic acids, the alicyclic dicarboxylic acids, and the dimerized aliphatic diacids, and more preferably contains a repeating unit derived from azelaic acid. Furthermore, the number of carbon atoms in the chain aliphatic dicarboxylic acids, aromatic dicarboxylic acids, and alicyclic dicarboxylic acids contained in the polyamide portion is preferably 6 to 12, more preferably 8 to 10. The number of carbon atoms in the dimerized aliphatic diacid contained in the polyamide portion is preferably 30 to 48, more preferably 32 to 40.

[0068] Examples of polyamines used in the polyamide portion of the polyester polyamide include diamines and aminocarboxylic acids similar to the polyamines used in the polyamides described above.

[0069] From the viewpoint of further improving the heat resistance of the cured product in a moisture-absorbing state, the polyamide portion preferably contains one or more repeating units selected from the group consisting of aromatic diamines having from 6 to 44 carbon atoms and diamines having an alicyclic skeleton having from 6 to 44 carbon atoms, more preferably contains a repeating unit derived from a diamine having an alicyclic skeleton having from 6 to 44 carbon atoms, and particularly preferably contains isophoronediamine. The diamine preferably has from 8 to 30 carbon atoms, more preferably from 10 to 24 carbon atoms.

[0070] From the same viewpoint, the polyamide portion of the polyester polyamide preferably contains repeating units derived from one or more dicarboxylic acids selected from the group consisting of open-chain aliphatic dicarboxylic acids having from 6 to 22 carbon atoms (excluding dimeric aliphatic diacids), aromatic dicarboxylic acids having from 6 to 22 carbon atoms, alicyclic dicarboxylic acids having from 6 to 22 carbon atoms (excluding dimeric aliphatic diacids), and dimeric aliphatic diacids having from 20 to 48 carbon atoms, and repeating units derived from one or more diamines selected from the group consisting of aromatic diamines having from 6 to 44 carbon atoms and diamines having an alicyclic skeleton having from 6 to 44 carbon atoms. It is more preferable that the polyamide portion of the polyester polyamide contains repeating units derived from one or more dicarboxylic acids selected from the group consisting of open-chain aliphatic dicarboxylic acids, alicyclic dicarboxylic acids, and dimeric aliphatic diacids, and diamines having an alicyclic skeleton.

[0071] The polyester polyamide also includes a polyester portion including a repeating unit derived from one or more dicarboxylic acids selected from the group consisting of a chain aliphatic dicarboxylic acid having from 6 to 22 carbon atoms, an aromatic dicarboxylic acid having from 6 to 22 carbon atoms, and an alicyclic dicarboxylic acid having from 6 to 22 carbon atoms, and a polyester portion including a repeating unit derived from one or more diols selected from the group consisting of a chain aliphatic diol having from 2 to 54 carbon atoms, an aromatic diol having from 2 to 54 carbon atoms, and an alicyclic diol having from 2 to 54 carbon atoms; It is preferable that the polyester polyamide comprises a polyamide moiety containing repeating units derived from one or more dicarboxylic acids selected from the group consisting of chain aliphatic dicarboxylic acids having from 6 to 22 carbon atoms (excluding dimeric aliphatic diacids), aromatic dicarboxylic acids having from 6 to 22 carbon atoms, alicyclic dicarboxylic acids having from 6 to 22 carbon atoms (excluding dimeric aliphatic diacids), and dimeric aliphatic diacids having from 20 to 48 carbon atoms, and repeating units derived from one or more diamines selected from the group consisting of aromatic diamines having from 6 to 44 carbon atoms and diamines having an alicyclic skeleton having from 6 to 44 carbon atoms. Such polyester polyamides containing polyester moieties and polyamide moieties can easily produce adhesive compositions that have low water absorption and excellent long-term moist heat resistance.

[0072] From the viewpoint of adhesiveness and heat resistance, the glass transition temperature of the polyester portion in the polyester polyamide is preferably 40°C or higher and 150°C or lower, more preferably 45°C or higher and 120°C or lower, even more preferably 50°C or higher and 90°C or lower, and particularly preferably 60°C or higher and 70°C or lower.

[0073] From the viewpoint of adhesiveness and heat resistance, the glass transition temperature of the polyester polyamide is preferably 30°C or higher and 150°C or lower, more preferably 40°C or higher and 140°C or lower, even more preferably 50°C or higher and 90°C or lower, and particularly preferably 60°C or higher and 70°C or lower.

[0074] From the viewpoint of heat resistance, the weight-average molecular weight of the polyester polyamide is preferably 5,000 to 150,000, more preferably 10,000 to 100,000, even more preferably 30,000 to 80,000, and particularly preferably 40,000 to 60,000. From the same viewpoint, the number-average molecular weight of the polyester polyamide is preferably 1,500 to 50,000, more preferably 10,000 to 25,000, and even more preferably 13,000 to 20,000.

[0075] From the viewpoint of adhesiveness, the amine value of the polyester polyamide is preferably 1.0 mgKOH / g or more and 12.0 mgKOH / g or less, more preferably 3.0 mgKOH / g or more and 11.0 mgKOH / g or less, even more preferably 6.0 mgKOH / g or more and 10.0 mgKOH / g or less, and particularly preferably 7.0 mgKOH / g or more and 8.0 mgKOH / g or less. The amine value of the resin in this specification is a value measured and calculated by potentiometry in accordance with JIS K 7237 (1995).

[0076] The method for producing polyester polyamide is not particularly limited, and known methods can be used. For example, the above-mentioned polycarboxylic acid, polyol, polyamine, and other compounds used as needed may all be placed in a reaction vessel and then reacted, or raw materials such as polycarboxylic acid may be added to the reaction vessel stepwise as the reaction progresses. In the polycondensation of polyester polyamide, the amounts of polycarboxylic acid, polyol, and polyamine added should be set so that the ratio of the total amount of carboxyl groups to the sum of the total amount of hydroxyl groups and the total amount of amino groups is preferably 0.9 to 1.1, more preferably 0.98 to 1.02, and particularly preferably 1.

[0077] The polycondensation reaction may be carried out in the presence of a solvent or without using a solvent. The solvent may be the same as that used in the polycondensation reaction of polyamide described above. From the viewpoint of reducing the environmental load, it is preferable to use ethyl acetate or methyl ethyl ketone as the solvent. The reaction apparatus in which the polycondensation reaction is carried out may be a reaction vessel equipped with a stirrer, or a mixing / kneading apparatus such as a kneader or a twin-screw extruder.

[0078] In producing polyester polyamide, a catalyst used for accelerating esterification and / or amidation reactions, such as tetrabutoxy titanate, can be used as needed to accelerate the esterification or amidation reaction. In addition, in producing polyester polyamide, a condensing agent, a chain extender, etc. can also be used as needed.

[0079] When producing polyester polyamide, a chain extender may be used as needed, such as the above-mentioned diols, compounds having one carboxy group and two hydroxy groups such as dimethylolpropionic acid and dimethylolbutanoic acid, and polyamines.

[0080] The chain extender is preferably a diol, more preferably a diol having a side chain, and even more preferably a diol having a branched chain. More specifically, the chain extender is preferably at least one compound selected from the group consisting of neopentyl glycol, 2-butyl-2-ethyl-1,3-propanediol, and 2,2-dimethylolpropionic acid, and particularly preferably contains at least one compound selected from the group consisting of neopentyl glycol and 2-butyl-2-ethyl-1,3-propanediol and 2,2-dimethylolpropionic acid.

[0081] When producing polyester polyamide, acid addition may be carried out as needed to introduce carboxy groups into the polyester polyamide. The amount of carboxy groups introduced by acid addition may be, for example, within a range of 0.1 mol% to 10 mol% based on the total of the repeating units derived from carboxylic acid and the repeating units derived from alcohol contained in the polyester polyamide. If a monocarboxylic acid, dicarboxylic acid, or polyfunctional carboxylic acid compound is used in acid addition to polyester polyamide, there is a risk of a decrease in molecular weight due to transesterification. Therefore, when acid addition is carried out to polyester polyamide, it is preferable to use an acid anhydride.

[0082] Examples of acid anhydrides include succinic anhydride, maleic anhydride, orthophthalic acid, 2,5-norbornene dicarboxylic anhydride, tetrahydrophthalic anhydride, trimellitic anhydride, pyromellitic anhydride (PMDA), oxydiphthalic dianhydride (ODPA), 3,3',4,4'-benzophenonetetracarboxylic dianhydride (BTDA), 3,3',4,4'-diphenyltetracarboxylic dianhydride (BPDA), 3,3',4,4'-diphenylsulfonetetracarboxylic dianhydride (DSDA), 4,4'-(hexafluoroisopropylidene)diphthalic dianhydride (6FDA), and 2,2'-bis[(dicarboxyphenoxy)phenyl]propane dianhydride (BSAA).

[0083] The acid addition method is not particularly limited, and examples include a method in which acid addition is performed in bulk after the polycondensation of polyester polyamide is completed, and a method in which acid addition is performed after the polyester polyamide is dissolved. The acid addition performed in bulk has the advantage of a fast reaction rate. On the other hand, when acid addition is performed in bulk, gelation is more likely to occur as the amount of acid added increases. Furthermore, when acid addition is performed in bulk, the reaction temperature becomes high, making the polyester polyamide more susceptible to oxidation. Therefore, when acid addition is performed in bulk, care must be taken to prevent oxidation by blocking oxygen gas. When acid addition is performed in solution, the reaction is slow, but a large number of carboxy groups can be stably introduced into the polyester polyamide.

[0084] Polyurethane The polyurethane-based resin used in the base resin (A) may be a polyurethane. The adhesive composition may contain one type of polyurethane or two or more types of polyurethane.

[0085] The polyurethane has repeating units derived from a polyol having two or more hydroxy groups, repeating units derived from a polyisocyanate having two or more isocyanate groups, and urethane bonds connecting these. The polyurethane may have two or more urethane bonds. The polyurethane may have repeating units derived from a diol and repeating units derived from a diisocyanate.

[0086] The polyurethane may contain repeating units derived from one type of polyisocyanate, or may contain repeating units derived from two or more types of polyisocyanates. The polyurethane preferably contains repeating units derived from a diisocyanate. Furthermore, the polyurethane may contain repeating units derived from a polyisocyanate having three or more isocyanates, in addition to repeating units derived from a diisocyanate.

[0087] Examples of diisocyanates include aromatic diisocyanates, aralkyl diisocyanates, chain aliphatic diisocyanates, alicyclic diisocyanates, and derivatives of these diisocyanates. From the viewpoint of suppressing yellowing of the polyurethane, it is preferable that the polyurethane contains a repeating unit derived from one or more diisocyanates selected from the group consisting of chain aliphatic diisocyanates and alicyclic diisocyanates, and it is more preferable that the polyurethane contains a repeating unit derived from an alicyclic diisocyanate.

[0088] Examples of aromatic diisocyanates include 1,3-phenylene diisocyanate, 1,4-phenylene diisocyanate, 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, 2,2'-diphenylmethane diisocyanate, 2,4'-diphenylmethane diisocyanate, 4,4'-diphenylmethane diisocyanate, 1,5-naphthalene diisocyanate, 2,6-naphthalene diisocyanate, 3,3'-dimethoxy-4,4'-biphenylene diisocyanate, and diphenyl ether-4,4'-diisocyanate.

[0089] Examples of aralkyl diisocyanates include m-xylylene diisocyanate, p-xylylene diisocyanate, and tetramethyl-m-xylylene diisocyanate.

[0090] Examples of the chain aliphatic diisocyanate include trimethylene diisocyanate, tetramethylene diisocyanate, pentamethylene diisocyanate, hexamethylene diisocyanate, 1,2-propylene diisocyanate, 1,2-butylene diisocyanate, 1,3-butylene diisocyanate, 2,3-butylene diisocyanate, 2,2,4-trimethylhexamethylene diisocyanate, and 2,4,4-trimethylhexamethylene diisocyanate.

[0091] Examples of alicyclic diisocyanates include 1,3-cyclopentane diisocyanate, 1,3-cyclohexane diisocyanate, 1,4-cyclohexane diisocyanate, 1-methylcyclohexane-2,4-diisocyanate, 1-methylcyclohexane-2,6-diisocyanate, 1,3-bis(isocyanatomethyl)cyclohexane, 1,4-bis(isocyanatomethyl)cyclohexane, 1,3-bis(isocyanatomethyl)cyclohexane, Examples of the isocyanatoisocyanate include 1,4-bis(isocyanatoethyl)cyclohexane, 1,4-bis(isocyanatoethyl)cyclohexane, 4,4'-methylenebis(cyclohexyl isocyanate), norbornane-2,5-diyldiisocyanate, norbornane-2,6-diyldiisocyanate, norbornane-2,5-diylbis(methylene)diisocyanate, norbornane-2,6-diylbis(methylene)diisocyanate, and isophorone diisocyanate.

[0092] Examples of diisocyanate derivatives include isocyanates having a uretdione group obtained by cyclodimerization of two isocyanate groups; isocyanates having an isocyanurate group or an iminooxadiazinedione group obtained by cyclotrimerization of three isocyanate groups; and isocyanates having a biuret group obtained by reacting three isocyanate groups with one molecule of water.

[0093] Polyurethanes may contain repeating units derived from one type of polyol, or may contain repeating units derived from two or more types of polyols. Examples of polyols used in polyurethanes include the diols used in the polyester polyamides described above and polyols having three or more hydroxy groups. Furthermore, polyols used in polyurethanes may also be diols having functional groups other than hydroxy groups. Examples of such diols include diols having one carboxy group, such as 2,2-bis(hydroxymethyl)propionic acid and 2,2-bis(hydroxymethyl)butanoic acid, and diols having one amino group, such as 2-amino-1,3-propanediol. The use of these diols makes it possible to obtain polyurethanes having functional groups other than hydroxy groups in their side chains.

[0094] The polyol used in the polyurethane may be a polymer having two or more hydroxy groups, such as a polycarbonate polyol, a polyolefin polyol, or a polyether polyol.

[0095] Examples of polycarbonate polyols used in polyurethane include polycarbonate polyols obtained by a dealcoholization reaction or a dephenolization reaction between a carbonate compound and a polyol.

[0096] Examples of carbonate compounds used in polycarbonate polyols include alkylene carbonates, dialkyl carbonates, and diaryl carbonates. Examples of alkylene carbonates include ethylene carbonate, trimethylene carbonate, 1,2-propylene carbonate, 1,2-butylene carbonate, 1,3-butylene carbonate, and 1,2-pentylene carbonate. Examples of dialkyl carbonates include dimethyl carbonate, diethyl carbonate, and dipropyl carbonate. Examples of diaryl carbonates include diphenyl carbonate. Polycarbonate polyols may contain repeating units derived from one type of carbonate compound among these carbonate compounds, or may contain repeating units derived from two or more types of carbonate compounds.

[0097] Examples of polyols used in polycarbonate polyols include ethylene glycol, 1,3-propanediol, propylene glycol, 1,3-butylene glycol, 1,4-butanediol, 1,5-pentanediol, neopentyl glycol, 1,6-hexanediol, 3-methyl-1,5-pentanediol, 1,4-cyclohexanedimethanol, 3,3'-dimethylolheptane, diethylene glycol, 1,4-bis(hydroxymethyl)cyclohexane, 1,4-bis(hydroxymethyl)cyclohexane, 1,5-bis(hydroxymethyl)cyclohexane, 1,6-hexanediol, 1,4-bis(hydroxymethyl)cyclohexane, 1,5-bis(hydroxymethyl)cyclohexane, 1,5-bis(hydroxymethyl)cyclohexane, 1,6-hexanediol, 1,4-bis(hydroxymethyl)cyclohexane, 1,5-bis(hydroxymethyl)cyclohexane, 1,5-bis(hydroxymethyl)cyclohexane, 1,5-bis(hydroxymethyl)cyclohexane, 1,6-hexanediol, 1,6-hexanediol, 1,4-bis(hydroxymethyl)cyclohexane, 1,5 ... diols such as 2,4-bis(hydroxyethyl)benzene and 2,2-bis(4,4'-hydroxycyclohexyl)propane; triols such as glycerin, trimethylolethane, trimethylolpropane and 1,2,6-hexanetriol; and polyols having four or more hydroxy groups such as pentaerythritol, diglycerin, α-methylglucoside, sorbitol, xylitol, mannitol, dipentaerythritol, glucose, fructose and sucrose. The polycarbonate polyol may contain repeating units derived from one of these polyols, or may contain repeating units derived from two or more polyols.

[0098] The number average molecular weight of the polycarbonate polyol is preferably 600 or more, more preferably 600 or more and 30,000 or less, even more preferably 800 or more and 10,000 or less, and particularly preferably 1,000 or more and 5,000 or less.

[0099] Examples of polyolefin polyols used in polyurethanes include polybutadiene polyols (e.g., diols in which hydroxy groups have been introduced at both molecular terminals of polybutadiene), hydrogenated polybutadiene polyols (e.g., diols in which hydroxy groups have been introduced at both molecular terminals of hydrogenated polybutadiene), polyisoprene polyols (e.g., diols in which hydroxy groups have been introduced at both molecular terminals of polyisoprene), and hydrogenated polyisoprene polyols (e.g., diols in which hydroxy groups have been introduced at both molecular terminals of hydrogenated polyisoprene).

[0100] The number average molecular weight of the polyolefin polyol is preferably 600 or more, more preferably 600 or more and 30,000 or less, even more preferably 800 or more and 10,000 or less, and particularly preferably 1,000 or more and 5,000 or less.

[0101] Examples of polyether polyols include aliphatic polyether diols and polyphenylene ether polyols.

[0102] Examples of aliphatic polyether diols include polyalkylene ether glycols such as polyethylene glycol, polypropylene glycol, polybutylene glycol, polytetramethylene ether glycol, etc. The number average molecular weight of the aliphatic polyether diol is preferably 600 or more, more preferably 600 or more and 30,000 or less, even more preferably 800 or more and 10,000 or less, and particularly preferably 1,000 or more and 5,000 or less.

[0103] In this specification, polyphenylene ether polyol refers to a compound having a polyphenylene ether skeleton consisting of multiple phenylene groups and ether bonds connecting these phenylene groups, and two or more hydroxy groups bonded to the phenylene groups in the polyphenylene ether. The hydroxy groups in the polyphenylene ether polyol may be bonded to the phenylene groups at the terminals of the polyphenylene ether skeleton, or to phenylene groups other than the terminals. By using such polyphenylene ether polyol, a polyphenylene ether skeleton containing multiple phenylene groups and ether bonds connecting the phenylene groups can be introduced into a polyurethane.

[0104] The polyphenylene ether polyol may be a polyphenylene ether diol having two hydroxy groups bonded to a polyphenylene ether skeleton, a polyphenylene ether triol having three hydroxy groups bonded to a polyphenylene ether skeleton, a polyphenylene ether polyol having four or more hydroxy groups bonded to a polyphenylene ether skeleton, etc. Among these, the polyphenylene ether polyol is preferably a polyphenylene ether diol having two hydroxy groups bonded to a polyphenylene ether skeleton.

[0105] The polyphenylene ether skeleton contains one or more phenylene groups selected from the group consisting of unsubstituted o-phenylene groups (1,2-phenylene groups), substituted o-phenylene groups, unsubstituted m-phenylene groups (1,3-phenylene groups), substituted m-phenylene groups, unsubstituted p-phenylene groups (1,4-phenylene groups), and substituted p-phenylene groups. The phenylene groups in the polyphenylene ether skeleton are preferably unsubstituted or substituted p-phenylene groups.

[0106] Examples of the substituent on the phenylene group include a linear or branched alkyl group having from 1 to 4 carbon atoms. The substituent on the phenylene group is preferably a methyl group or an ethyl group, and more preferably a methyl group.

[0107] The phenylene groups in the polyphenylene ether polyol may all have the same structure, or some of the phenylene groups may have a structure different from that of the other phenylene groups.

[0108] There is no limitation on the molecular weight of the polyphenylene ether polyol. For example, the number average molecular weight of the polyphenylene ether polyol is preferably 500 or more and 10,000 or less, more preferably 700 or more and 8,000 or less, and even more preferably 1,000 or more and 6,000 or less.

[0109] The polyphenylene ether polyol may have, for example, a phenylene oxide in which the phenylene is substituted with two alkyl groups as a structural unit. In this case, all of the alkyl groups in the molecule may have the same structure, or the structure of some of the alkyl groups may be different from the structure of the other alkyl groups. The alkyl groups are preferably linear or branched alkyl groups having 1 to 4 carbon atoms.

[0110] More specifically, the polyphenylene ether polyol may have, for example, 2,6-dialkyl-1,4-phenylene oxide as a constituent unit. Furthermore, the polyphenylene ether polyol may have, for example, phenylene oxide in which the phenylene is substituted with two methyl groups (i.e., dimethylphenylene oxide) as a constituent unit. Furthermore, the polyphenylene ether polyol may have, for example, 2,6-dimethyl-1,4-phenylene oxide as a constituent unit.

[0111] The polyphenylene ether polyol may be, for example, a compound represented by the following general formula (A1).

[0112]

[0113] In the general formula (A1), L represents a single bond or a divalent linking group, and R 4 represents a hydrogen atom or an alkyl group, and m and n each independently represent an integer of 1 or more. 4 may all be the same, and some R 4 Other R4 may be different from

[0114] In the general formula (A1), the divalent linking group represented by L is, for example, an oxygen atom or —C(R 5 )(R 6 )-, where R 5 and R 6 R each independently represents a hydrogen atom, a linear or branched alkyl group having 1 to 6 carbon atoms, or a phenyl group. The hydrogen atoms of the alkyl group and the phenyl group may be substituted with a halogen atom (e.g., a fluorine atom). 5 and R 6 The rings may be linked to each other to form a ring.

[0115] Below -C(R 5 )(R 6 )-, -C(R 5 )(R 6 In the following structural formulae, "*" indicates the position of connection to the phenylene group.

[0116]

[0117] R in the general formula (A1) 4 is preferably a hydrogen atom or a linear or branched alkyl group having from 1 to 4 carbon atoms, more preferably a hydrogen atom, a methyl group, or an ethyl group, and even more preferably a hydrogen atom or a methyl group. In addition, the sum of m and n in general formula (A1) is preferably a number corresponding to the number average molecular weight described above.

[0118] The polyphenylene ether polyol may be a compound represented by the following general formula (A2): 4 Specific embodiments of L, m, and n are R 4 , L, m and n.

[0119]

[0120] R in the general formula (A2) 4is preferably a linear or branched alkyl group having from 1 to 4 carbon atoms, more preferably a methyl group or an ethyl group, and even more preferably a methyl group. In addition, the sum of m and n in the general formula (A2) is preferably a number corresponding to the number average molecular weight described above.

[0121] The polyphenylene ether polyol may be a compound represented by the following general formula (A3).

[0122]

[0123] In the general formula (A3), p and q each independently represent an integer of 1 or greater. The sum of p and q in the general formula (A3) is preferably a number corresponding to the number average molecular weight described above. An example of the compound represented by the general formula (A3) is "Noryl (registered trademark) SA90" manufactured by SABIC.

[0124] The content of repeating units derived from the polyphenylene ether polyol in the polyurethane having a polyphenylene ether skeleton is preferably 30% by mass or more, more preferably 50% by mass or more, and even more preferably 70% by mass or more, based on all repeating units contained in the polyurethane, which can increase the glass transition temperature of the polyurethane, further improve the heat resistance, and further reduce the water absorption of the polyurethane.

[0125] On the other hand, from the viewpoint of increasing the flexibility of the polyurethane, the content of repeating units derived from the polyphenylene ether polyol in the polyurethane having a polyphenylene ether skeleton is preferably 95% by mass or less, more preferably 90% by mass or less, and even more preferably 80% by mass or less, based on all repeating units contained in the polyurethane.

[0126] When determining a preferred range of the content of the repeating units derived from the polyphenylene ether polyol, the above-mentioned upper and lower limits of the content of the repeating units derived from the polyphenylene ether polyol can be combined arbitrarily. For example, the preferred range of the content of the repeating units derived from the polyphenylene ether polyol may be 30% by mass or more and 95% by mass or less, 50% by mass or more and 90% by mass or less, or 70% by mass or more and 80% by mass or less.

[0127] Furthermore, when the polyurethane has a polyphenylene ether skeleton, it is preferable that the polyurethane further contains a repeating unit derived from a polymer polyol other than polyphenylene ether polyol. The content of the repeating unit derived from the polymer polyol is preferably 1 part by mass or more and 120 parts by mass or less, more preferably 10 parts by mass or more and 100 parts by mass or less, and even more preferably 20 parts by mass or more and 80 parts by mass or less, per 100 parts by mass of the repeating unit derived from polyphenylene ether polyol.

[0128] Furthermore, when the polyurethane has a polyphenylene ether skeleton, it is preferable that the polyurethane further contains a repeating unit derived from a diol having a functional group other than a hydroxy group. The content of the repeating unit derived from a diol having a functional group other than a hydroxy group is preferably 0.1 parts by mass or more and 30 parts by mass or less, more preferably 0.5 parts by mass or more and 20 parts by mass or less, and even more preferably 1 part by mass or more and 5 parts by mass or less, per 100 parts by mass of the repeating unit derived from the polyphenylene ether polyol.

[0129] More specifically, the polyurethane may contain, for example, a repeating unit derived from a polyphenylene ether polyol and a repeating unit derived from a diol having a carboxy group. In this case, the content of the diol having a carboxy group is preferably 0.1 to 20 parts by mass, more preferably 0.5 to 10 parts by mass, and even more preferably 1 to 5 parts by mass, per 100 parts by mass of the repeating unit derived from the polyphenylene ether polyol.

[0130] The polyurethane may contain, for example, a repeating unit derived from a polyphenylene ether polyol and a repeating unit derived from a diol having an amino group. In this case, the content of the repeating unit derived from the diol having an amino group is preferably 0.1 to 20 parts by mass, more preferably 0.5 to 10 parts by mass, and even more preferably 1 to 5 parts by mass, per 100 parts by mass of the repeating unit derived from the polyphenylene ether polyol.

[0131] The polyurethane may contain a structural unit derived from a chain extender as necessary. The use of a chain extender can, for example, impart properties to the polyurethane depending on the intended use of the polyurethane or introduce a side chain into the polyurethane. As the chain extender, for example, one or more compounds selected from known compounds used as polyurethane chain extenders can be used. The chain extender may be a monomer or a polymer.

[0132] The chain extender used in the polyurethane is preferably a compound having no functional groups other than hydroxy groups, more preferably a polyol having no functional groups other than hydroxy groups, and even more preferably a diol having no functional groups other than hydroxy groups.

[0133] When the compound having no functional groups other than hydroxy groups, polyol, and diol used as a chain extender are polymers, the number average molecular weight thereof is preferably 500 or less, more preferably 400 or less, even more preferably 300 or less, and particularly preferably 50 or less.

[0134] Furthermore, when the compound having no functional groups other than hydroxy groups, polyol, and diol used as a chain extender are monomers, the molecular weight thereof is preferably 500 or less, more preferably 400 or less, even more preferably 300 or less, and particularly preferably 50 or less.

[0135] Examples of the chain extender include diols such as ethylene glycol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, neopentyl glycol, 1,6-hexanediol, 3-methyl-1,5-pentanediol, 1,4-cyclohexanedimethanol, 2-butyl-2-ethyl-1,3-propanediol, and 1,4-bis(2-hydroxyethoxy)benzene; and triols such as glycerin, trimethylolethane, trimethylolpropane, and 1,2,6-hexanetriol.

[0136] The content of the structural units derived from the chain extender is not particularly limited, but may be, for example, 1 part by mass or more and 30 parts by mass or less, 3 parts by mass or more and 25 parts by mass or less, or 5 parts by mass or more and 20 parts by mass or less, per 100 parts by mass of the structural units derived from the polyphenylene ether polyol.

[0137] The glass transition temperature of the polyurethane is preferably 100°C or higher, more preferably 110°C or higher, and even more preferably 120°C or higher. In this case, the heat resistance of the polyurethane can be further improved. The upper limit of the glass transition temperature of the polyurethane is usually 200°C.

[0138] The glass transition temperature of polyurethane is a value determined by dynamic viscoelasticity measurement. More specifically, a dried polyurethane film is used as a test piece, and dynamic viscoelasticity measurement of the test piece is performed in a tensile mode under conditions of a temperature rise rate of 2°C / min and a frequency of 1 Hz, and the maximum value of the loss tangent of the obtained curve is taken as the glass transition temperature.

[0139] From the viewpoint of processability, the weight average molecular weight of the polyurethane is preferably 30,000 or more, more preferably 50,000 or more, and even more preferably 70,000 or more. From the viewpoint of solubility in organic solvents, the weight average molecular weight of the polyurethane is preferably 200,000 or less.

[0140] From the viewpoint of processability, the number average molecular weight of the polyurethane is preferably 5,000 or more, more preferably 8,000 or more, and even more preferably 10,000 or more. From the viewpoint of solubility in organic solvents, the number average molecular weight of the polyurethane is preferably 40,000 or less.

[0141] From the viewpoint of solubility in organic solvents, the acid value of the polyurethane is preferably 0 mgKOH / g or more and 30 mgKOH / g or less, more preferably 1 mgKOH / g or more and 20 mgKOH / g or less, and even more preferably 2 mgKOH / g or more and 10 mgKOH / g or less. The acid value of the polyurethane is a value measured by neutralization titration of a sample with a potassium hydroxide benzyl alcohol solution using a phenolphthalein solution as an indicator.

[0142] The method for producing the polyurethane is not particularly limited, and known methods can be used. For example, the polyol, polyisocyanate, and other compounds used as needed may all be placed in a reaction vessel and then reacted, or raw materials such as polyol may be added to the reaction vessel in stages as the reaction progresses. In the polycondensation of polyester polyurethane, the amounts of raw materials added may be set so that the ratio of the total amount of isocyanate groups to the total amount of hydroxy groups is preferably 0.9 to 1.1, more preferably 0.98 to 1.02, and particularly preferably 1.

[0143] The polycondensation reaction may be carried out in the presence of a solvent inert to isocyanate groups, or may be carried out without using a solvent. The solvent may be the same as that used in the polycondensation reaction of polyamide described above. From the viewpoint of reducing environmental impact, it is preferable to use ethyl acetate or methyl ethyl ketone as the solvent. The reaction apparatus used to carry out the polycondensation reaction may be a reaction vessel equipped with a stirrer, or a mixing / kneading apparatus such as a kneader or a twin-screw extruder.

[0144] In producing polyurethane, a catalyst for accelerating the urethanization reaction can be used as needed to accelerate the urethanization reaction. Examples of this type of catalyst include tin-based catalysts such as trimethyltin laurate, dimethyltin dilaurate, trimethyltin hydroxide, dimethyltin dihydroxide, and stannous octoate; lead-based catalysts such as red oleate and red 2-ethylhexoate; and amine-based catalysts such as triethylamine, tributylamine, morpholine, diazabicyclooctane, and diazabicycloundecene.

[0145] Polyester Polyurethane The polyurethane resin used in the base resin (A) may be a polyester polyurethane. The adhesive composition may contain one type of polyester polyurethane, or two or more types of polyester polyurethane.

[0146] The polyester polyurethane has a polyester portion formed by bonding multiple repeating units via ester bonds and a polyurethane portion formed by bonding multiple repeating units via urethane bonds. The polyester portion may have two or more ester bonds. The polyurethane portion may have two or more urethane bonds. The polyester portion and the polyurethane portion may be bonded via an ester bond or a urethane bond.

[0147] The polyester polyurethane has, for example, a repeating unit derived from a polycarboxylic acid, a repeating unit derived from a polyol, and a repeating unit derived from a polyisocyanate. The polyester polyurethane may also have, for example, a repeating unit derived from a dicarboxylic acid, a repeating unit derived from a diol, and a repeating unit derived from a diisocyanate.

[0148] Furthermore, the polyester polyurethane may contain repeating units derived from a polyester polyol, repeating units derived from a polyisocyanate, and a structure derived from a chain extender, or may contain repeating units derived from a polyester polyol, repeating units derived from a polyisocyanate, and a structure derived from a diol compound as a chain extender.

[0149] More specifically, the polyester portion of the polyester polyurethane has a repeating unit derived from a polycarboxylic acid and a repeating unit derived from a polyol. The number average molecular weight of the polyester portion of the polyester polyurethane is preferably 1,000 to 50,000, more preferably 2,000 to 40,000, even more preferably 3,000 to 30,000, particularly preferably 8,000 to 30,000, and most preferably 15,000 to 30,000. In this case, the heat resistance of the cured product in a moisture-absorbed state can be further improved.

[0150] Examples of the polycarboxylic acid used in the polyester portion include the same dicarboxylic acids as those used in the polyamides described above, polycarboxylic acids having three or more carboxy groups, hydroxycarboxylic acids, and sulfocarboxylic acids.

[0151] The polyester portion of the polyester polyurethane preferably contains 30 mol% or more of repeating units derived from an aromatic carboxylic acid, more preferably 45 mol% or more of repeating units derived from an aromatic carboxylic acid, and even more preferably 60 mol% or more of repeating units derived from an aromatic carboxylic acid, relative to the total amount of repeating units derived from a polycarboxylic acid contained in the polyester portion. In this case, the adhesive composition can have further improved adhesion, heat resistance, and moist heat resistance. Examples of aromatic carboxylic acids include aromatic polycarboxylic acids, aromatic sulfocarboxylic acids, and aromatic oxycarboxylic acids. From the perspective of further improving the adhesive properties of the adhesive composition, the polyester portion preferably contains repeating units derived from one or two aromatic carboxylic acids selected from terephthalic acid and isophthalic acid. From the same perspective, it is more preferable that the aromatic carboxylic acid contained in the polyester portion is terephthalic acid and / or isophthalic acid.

[0152] Furthermore, examples of the polyol used in the polyester portion include the same diols and polyols as those used in the polyamide described above. From the viewpoints of compatibility with the epoxy compound (B) and solution stability, the polyester portion preferably contains a repeating unit derived from a diol having a side chain. The side chain of the diol is preferably an alkyl group, more preferably an alkyl group having 1 to 5 carbon atoms. Examples of diols having a side chain include neopentyl glycol, 2-butyl-2-ethyl-1,3-propanediol, and 2,2-dimethylolpropionic acid.

[0153] Furthermore, it is preferable that the polyester portion contains a repeating unit derived from a diol. In this case, the heat resistance of the cured product in a moisture-absorbed state can be further improved. From the viewpoint of more reliably obtaining this effect, it is preferable that the polyester portion contains a repeating unit derived from a diol having a hydrocarbon group with 5 to 32 carbon atoms, more preferably a repeating unit derived from a diol having a hydrocarbon group with 5 to 16 carbon atoms, and particularly preferably a repeating unit derived from a diol having a hydrocarbon group with 7 to 12 carbon atoms.

[0154] From the same viewpoint, the repeating unit derived from the diol in the polyester portion preferably has a hydrocarbon group having from 5 to 32 carbon atoms and also has an alicyclic structure or two or more side chains, more preferably two or more side chains, and particularly preferably two side chains. The repeating unit derived from the diol described above may be contained in the polyester portion or, as will be described later, in the polyurethane portion, but from the viewpoint of more reliably obtaining the effects described above, it is preferable that the repeating unit derived from the diol described above be contained in the polyurethane portion.

[0155] The polyester portion of the polyester polyurethane may have a repeating unit derived from a polycarboxylic acid having three or more carboxy groups and / or a repeating unit derived from a polyol having three or more hydroxy groups. In this case, a branched chain can be introduced into the polyester portion. Furthermore, by introducing a branched chain into the polyester portion, the terminal group concentration (i.e., the number of reaction sites) of the resin can be increased. Therefore, for example, by reacting a polyester polyurethane having a branched chain introduced therein with a curing agent, a cured layer with a high crosslink density can be obtained.

[0156] The total content of the repeating units derived from polycarboxylic acid and the repeating units derived from polyol is preferably 0.1 mol % or more and 5 mol % or less, and more preferably 0.1 mol % or more and 3 mol % or less, based on all repeating units in the polyester portion.

[0157] The polyurethane portion of the polyester polyurethane preferably contains a repeating unit derived from a diisocyanate, and more preferably contains a repeating unit derived from a diisocyanate having a hydrocarbon group having from 8 to 14 carbon atoms. A methylene group in the hydrocarbon group of the diisocyanate may be replaced with a non-reactive bond such as -O-, -S-, -CO-, -COO-, or -OCO-.

[0158] From the viewpoint of further improving the heat resistance of the cured product after moisture absorption, the number of carbon atoms in the hydrocarbon group in the diisocyanate is more preferably 8 to 12, and even more preferably 8 to 10. From the same viewpoint, the diisocyanate preferably has an alicyclic structure.

[0159] The content of the repeating units derived from the diisocyanate in the polyurethane portion is preferably 70 mol% or more, more preferably 90 mol% or more, and even more preferably 100 mol% of the content of all repeating units derived from diisocyanates contained in the polyester polyurethane.

[0160] From the viewpoint of further improving the adhesive properties of the adhesive composition, the content of repeating units derived from diisocyanate in the polyester polyurethane is preferably 5 to 50 molar equivalents per 1 molar equivalent of the polyester moiety. In other words, the polyester polyurethane preferably has urethane bonds derived from diisocyanate in an amount of 10 to 100 molar equivalents per 1 molar equivalent of the polyester moiety.

[0161] The polyurethane portion of the polyester polyurethane may contain, in addition to repeating units derived from diisocyanates, repeating units derived from monoisocyanates and repeating units derived from polyisocyanates having three or more isocyanates.

[0162] Examples of polyisocyanates used in the polyurethane portion include diisocyanates similar to those used in the polyurethanes described above, and polyisocyanates having three or more isocyanate groups. The polyurethane portion preferably contains repeating units derived from one or more isocyanates selected from the group consisting of chain aliphatic diisocyanates and alicyclic diisocyanates, and more preferably contains repeating units derived from alicyclic diisocyanates. In this case, the cured product of the adhesive composition can be made transparent. Furthermore, in this case, the heat resistance of the cured product in a moisture-absorbed state can be further improved.

[0163] Furthermore, from the viewpoint of availability, it is more preferable that the polyurethane portion contains repeating units derived from one or more isocyanates selected from the group consisting of 1,3-bis(isocyanatomethyl)cyclohexane, 1,4-bis(isocyanatomethyl)cyclohexane, methylenebis(4-cyclohexyldiisocyanate), and norbornane diisocyanate, and it is particularly preferable that the polyurethane portion contains repeating units derived from 1,3-bis(isocyanatomethyl)cyclohexane.

[0164] The polyurethane portion may contain a repeating unit derived from a polyol. Examples of polyols used in the polyurethane portion include diols similar to the alcohols used in the polyester polyamides described above and polyols having three or more hydroxy groups. The polyurethane portion preferably contains a repeating unit derived from a diol having a side chain. The side chain of the diol is preferably an alkyl group, more preferably an alkyl group having 1 to 5 carbon atoms.

[0165] Furthermore, it is preferable that the polyurethane portion contains a repeating unit derived from a diol. In this case, the heat resistance of the cured product in a moisture-absorbing state can be further improved. From the viewpoint of more reliably obtaining this effect, it is preferable that the polyurethane portion contains a repeating unit derived from a diol having a hydrocarbon group with 5 to 32 carbon atoms, more preferably a repeating unit derived from a diol having a hydrocarbon group with 5 to 16 carbon atoms, and particularly preferably a repeating unit derived from a diol having a hydrocarbon group with 7 to 12 carbon atoms.

[0166] From the same viewpoint, the repeating unit derived from a diol in the polyurethane portion preferably has a hydrocarbon group having from 5 to 32 carbon atoms and also has an alicyclic structure or two or more side chains, more preferably has two or more side chains, and particularly preferably has two side chains.

[0167] Examples of chain extenders used in polyester polyurethanes include diols similar to those used in the polyester portion, and compounds having one carboxy group and two hydroxy groups, such as dimethylolpropionic acid and dimethylolbutanoic acid.

[0168] From the viewpoint of further enhancing the dispersibility of the filler, the chain extender is preferably a diol. Furthermore, from the viewpoint of further improving compatibility with the epoxy compound (B) and the like and solution stability in addition to the above effect, the chain extender is more preferably a diol having a side chain, and particularly preferably a diol having a branched chain. Furthermore, the side chain of the diol is preferably an alkyl group, more preferably an alkyl group having 1 to 5 carbon atoms. More specifically, the chain extender preferably contains at least one compound selected from the group consisting of neopentyl glycol, 2-butyl-2-ethyl-1,3-propanediol, and 2,2-dimethylolpropionic acid, and particularly preferably contains at least one compound selected from the group consisting of neopentyl glycol and 2-butyl-2-ethyl-1,3-propanediol and 2,2-dimethylolpropionic acid.

[0169] Polyamines can also be used as chain extenders. In this case, urea bonds are formed in the polyester polyurethane, but in some cases, it may be preferable for the polyester polyurethane to contain no urea bonds.

[0170] From the viewpoints of adhesiveness and heat resistance, the glass transition temperature of the polyester portion of the polyester polyurethane is preferably 40°C or higher and 150°C or lower, more preferably 45°C or higher and 120°C or lower, even more preferably 50°C or higher and 90°C or lower, and particularly preferably 60°C or higher and 70°C or lower.

[0171] From the viewpoints of adhesiveness and heat resistance, the glass transition temperature of the polyester polyurethane is preferably 30°C or higher and 150°C or lower, more preferably 40°C or higher and 140°C or lower, even more preferably 50°C or higher and 90°C or lower, and particularly preferably 60°C or higher and 70°C or lower.

[0172] From the viewpoint of heat resistance, the number average molecular weight of the polyester polyurethane is preferably 5,000 or more and 100,000 or less, more preferably 10,000 or more and 80,000 or less, even more preferably 20,000 or more and 60,000 or less, and particularly preferably 25,000 or more and 50,000 or less.

[0173] From the viewpoint of heat resistance, the molecular weight per urethane bond in the polyester polyurethane is preferably 200 to 8,000, more preferably 200 to 5,000, even more preferably 300 to 2,000, particularly preferably 400 to 1,500, and most preferably 700 to 1,000. The molecular weight per urethane bond can be obtained by dividing the number average molecular weight of the polyester polyurethane by the number of urethane bonds per molecule. The number of urethane bonds per molecule can also be calculated, for example, based on the amounts of raw materials used in the synthesis of the polyester polyurethane. More specifically, when polyester polyol and isocyanate are used to synthesize the polyester polyurethane, the number of moles of isocyanate groups reacted with 1 mole of polyester polyol can be considered to be the "number of urethane bonds per molecule."

[0174] The method for producing polyester polyurethane is not particularly limited, and known methods can be used. For example, the above-mentioned polyester polyol, isocyanate, and other compounds used as needed may all be placed in a reaction vessel and then reacted, or raw materials such as polyester polyol may be added to the reaction vessel in stages as the reaction progresses. In the polycondensation of polyester polyurethane, the amounts of raw materials added may be set so that the ratio of the total amount of isocyanate groups to the total amount of hydroxy groups is preferably 0.9 to 1.1, more preferably 0.98 to 1.02, and particularly preferably 1.

[0175] The polycondensation reaction may be carried out in the presence of a solvent inert to isocyanate groups, or may be carried out without using a solvent. The solvent may be the same as that used in the polyurethane polycondensation reaction described above. From the viewpoint of reducing environmental impact, it is preferable to use ethyl acetate or methyl ethyl ketone as the solvent. The reaction apparatus used to carry out the polycondensation reaction may be a reaction vessel equipped with a stirrer, or a mixing / kneading apparatus such as a kneader or a twin-screw extruder.

[0176] In producing polyester polyurethane, a catalyst for accelerating the urethanization reaction can be used as needed to accelerate the urethanization reaction. Examples of this type of catalyst include the same catalysts used for polyurethanes as described above.

[0177] When producing polyester polyurethane, acid addition may be performed as needed to introduce carboxy groups into the polyester polyurethane. The amount of carboxy groups introduced by acid addition may be, for example, within a range of 0.1 mol % to 10 mol % relative to the carboxylic acid-derived repeating units and alcohol-derived repeating units contained in the polyester polyurethane. If a monocarboxylic acid, dicarboxylic acid, or polyfunctional carboxylic acid compound is used in acid addition to polyester polyurethane, there is a risk of a decrease in molecular weight due to ester exchange. Therefore, when acid addition is performed on polyester polyurethane, it is preferable to use an acid anhydride. Examples of acid anhydrides used in acid addition to polyester polyurethane include the same acid anhydrides as those used in acid addition to polyester polyamide.

[0178] [Epoxy Compound (B)] The adhesive composition contains 1 part by mass or more and 50 parts by mass or less of epoxy compound (B) per 100 parts by mass of base resin (A). The epoxy compound (B) imparts adhesive properties to the adhesive composition and has the effect of improving the heat resistance of a cured product of the adhesive composition. By adjusting the content of epoxy compound (B) to 1 part by mass or more, preferably 5 parts by mass or more, and more preferably 10 parts by mass or more per 100 parts by mass of base resin (A), the adhesive properties of the adhesive composition can be increased and the heat resistance of the cured product can be improved. If the content of epoxy compound (B) is less than 1 part by mass per 100 parts by mass of base resin (A), the adhesive properties of the adhesive composition and the heat resistance of the cured product may be reduced.

[0179] On the other hand, if the content of the epoxy compound (B) is excessively high, the epoxy compound (B) may be more likely to react with other functional groups in the adhesive composition, which may result in a decrease in storage stability. This problem can be easily avoided by setting the content of the epoxy compound (B) to 50 parts by mass or less, preferably 40 parts by mass or less, more preferably 30 parts by mass or less, even more preferably 25 parts by mass or less, and particularly preferably 20 parts by mass or less, per 100 parts by mass of the base resin (A).

[0180] When constituting a preferred range of the content of the epoxy compound (B), the above-mentioned upper and lower limits of the content of the epoxy compound (B) can be combined arbitrarily. For example, the preferred range of the content of the epoxy compound (B) may be 5 parts by mass or more and 40 parts by mass or less, 5 parts by mass or more and 30 parts by mass or less, 5 parts by mass or more and 25 parts by mass or less, or 10 parts by mass or more and 20 parts by mass or less, relative to 100 parts by mass of the base resin (A).

[0181] The adhesive composition may contain one type of epoxy compound (B), or may contain two or more types of epoxy compounds (B) having different structures. The epoxy compound (B) preferably has two or more epoxy groups per molecule.

[0182] Examples of the epoxy compound (B) include glycidyl esters, glycidyl ethers, and epoxy resins. Examples of the glycidyl esters include orthophthalic acid diglycidyl ester, isophthalic acid diglycidyl ester, terephthalic acid diglycidyl ester, p-hydroxybenzoic acid diglycidyl ester, tetrahydrophthalic acid diglycidyl ester, succinic acid diglycidyl ester, adipic acid diglycidyl ester, sebacic acid diglycidyl ester, and trimellitic acid triglycidyl ester.

[0183] Examples of glycidyl ethers include diglycidyl ether of bisphenol A and oligomers thereof, ethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, 1,4-butanediol diglycidyl ether, 1,6-hexanediol diglycidyl ether, trimethylolpropane triglycidyl ether, pentaerythritol tetraglycidyl ether, tetraphenyl glycidyl ether ethane, triphenyl glycidyl ether ethane, polyglycidyl ether of sorbitol, and polyglycidyl ether of polyglycerol.

[0184] Examples of epoxy resins include novolac type epoxy resins such as phenol novolac epoxy resin, o-cresol novolac epoxy resin, and bisphenol A novolac epoxy resin; brominated bisphenol A type epoxy resin; phosphorus-containing epoxy resin; trisphenolmethane skeleton-containing epoxy resin; dicyclopentadiene skeleton-containing epoxy resin; naphthalene skeleton-containing epoxy resin; anthracene type epoxy resin; tertiary butylcatechol type epoxy resin; biphenyl type epoxy resin; and bisphenol S type epoxy resin.

[0185] From the viewpoint of adhesiveness and solder heat resistance, the adhesive composition preferably contains an epoxy resin containing a trisphenolmethane skeleton as the epoxy compound (B).

[0186] From the viewpoint of further improving the heat resistance of the cured product of the adhesive composition, it is preferable that the epoxy compound (B) contains a compound having three or more epoxy groups in one molecule. Use of such a compound increases the crosslinking reactivity with the base resin (A), thereby further improving the heat resistance of the cured product.

[0187] From the viewpoint of further enhancing the effect of improving heat resistance, the content of the compound having three or more epoxy groups in one molecule is preferably 15% by mass or more, more preferably 20% by mass or more, and particularly preferably 25% by mass or more, based on the total mass of the epoxy compound (B).

[0188] [Triazine-based compound (C)] The adhesive composition contains 10 parts by mass or more and 70 parts by mass or less of a triazine-based compound (C) per 100 parts by mass of the base resin (A). The triazine-based compound (C) contains, in its molecular structure, one or more structures selected from the structure represented by the following general formula (C1) and the structure represented by the following structural formula (C2). The adhesive composition may contain one type of triazine-based compound (C), or may contain two or more types of triazine-based compounds (C).

[0189]

[0190] However, R in the general formula (C1) 1 ~R 3 each independently represents an amino group, a hydroxy group, a thiol group, a methyl group, or a phenyl group.

[0191]

[0192] The triazine-based compound (C) containing the partial structure represented by the general formula (C1) or the partial structure represented by the structural formula (C2) when used in combination with the metal phosphinate (D) not only improves the heat resistance of the cured product but also improves the heat resistance of the cured product in a hygroscopic state. Therefore, by setting the content of the triazine-based compound (C) containing the specific partial structure within the specific range, the heat resistance of the cured product in a hygroscopic state can be improved.

[0193] From the viewpoint of more reliably obtaining the above-mentioned effects, the content of the triazine-based compound (C) is preferably 13 parts by mass or more, more preferably 15 parts by mass or more, and even more preferably 17 parts by mass or more, per 100 parts by mass of the base resin (A). If the content of the triazine-based compound (C) is less than 10 parts by mass per 100 parts by mass of the base resin (A), the above-mentioned effects will be reduced, and the heat resistance of the cured product in a moisture-absorbed state may be reduced.

[0194] On the other hand, if the content of the triazine compound (C) is excessively high, the content of the triazine compound (C) will be excessive relative to the amount of the metal phosphinate (D), which may make it difficult to achieve the above-mentioned effects. In this case, the proportion of the base resin (A) will be relatively low, which may result in a decrease in initial adhesion. By setting the content of the triazine compound (C) to 70 parts by mass or less, preferably 50 parts by mass or less, more preferably 40 parts by mass or less, even more preferably 30 parts by mass or less, and particularly preferably 25 parts by mass or less, per 100 parts by mass of the base resin (A), the balance between the triazine compound (C) and the metal phosphinate (D) can be maintained within an appropriate range, and the above-mentioned effects can be more reliably achieved.

[0195] When determining a preferred range of the content of the triazine compound (C), the above-mentioned upper and lower limits of the content of the triazine compound (C) can be combined in any manner. For example, the preferred range of the content of the triazine compound (C) may be 13 parts by mass or more and 50 parts by mass or less, 15 parts by mass or more and 40 parts by mass or less, 15 parts by mass or more and 30 parts by mass or less, 15 parts by mass or more and 25 parts by mass or less, or 17 parts by mass or more and 25 parts by mass or less.

[0196] The triazine-based compound (C) may be a compound represented by the general formula (C1) or structural formula (C2), or may be a salt of these compounds. More specifically, examples of the triazine-based compound (C) include melamine, acetoguanamine, benzoguanamine, trithiocyanuric acid, cyanuric acid, and isocyanuric acid. The triazine-based compound (C) may also be a salt of a compound represented by the general formula (C1) or structural formula (C2), such as melamine phosphate, melamine polyphosphate, and melamine cyanurate.

[0197] From the viewpoint of further improving the heat resistance of the cured product in a moisture-absorbed state, the triazine-based compound (C) preferably contains a structure represented by the following structural formula (C3) in its molecular structure: That is, the triazine-based compound (C) is preferably one or more compounds selected from the group consisting of melamine and salts of melamine.

[0198]

[0199] The triazine compound (C) preferably has a volume-based median diameter of 10 μm or less, which further improves the dispersibility of the triazine compound (C) in the adhesive composition, thereby further increasing the heat resistance of the cured product in a moisture-absorbed state.

[0200] The median diameter of the triazine compound (C) is a value calculated based on the volumetric particle size distribution obtained by measuring the triazine compound (C) using a laser diffraction / scattering particle size distribution analyzer (for example, "LS 13320" manufactured by Beckman Coulter, Inc.) with a Tornado dry powder sample module. More specifically, the median diameter of the triazine compound (C) indicates the particle size at which the integrated volume of particles, starting from the fine particle side, is 50% by volume in the volumetric particle size distribution.

[0201] [Metal Phosphinate (D)] The adhesive composition contains 0.5 parts by mass or more and 50 parts by mass or less of the metal phosphinate (D) per 100 parts by mass of the base resin (A). The adhesive composition may contain one type of metal phosphinate (D), or may contain two or more types of metal phosphinate (D). By adjusting the content of the metal phosphinate (D) in the adhesive composition to fall within the above-mentioned specific range, the flame retardancy of the cured product of the adhesive composition can be improved. Furthermore, by using the metal phosphinate (D) in combination with the triazine compound (C), the heat resistance of the cured product in a moisture-absorbed state can be improved.

[0202] From the viewpoint of more reliably obtaining the above-mentioned effects, the content of the metal phosphinate (D) is preferably 1 part by mass or more, more preferably 3 parts by mass or more, and even more preferably 5 parts by mass or more, per 100 parts by mass of the base resin (A). If the content of the metal phosphinate (D) is less than 0.5 parts by mass per 100 parts by mass of the base resin (A), the flame retardancy of the cured product may be reduced.

[0203] On the other hand, the metal phosphinate (D) has a tendency to easily absorb moisture. Therefore, if the content of the metal phosphinate (D) is excessively large relative to the amount of the triazine-based compound (C), the influence of moisture absorption by the metal phosphinate (D) becomes large, and the heat resistance of the cured product in a moisture-absorbing state may be reduced. By setting the content of the metal phosphinate (D) to 50 parts by mass or less, preferably 40 parts by mass or less, more preferably 30 parts by mass or less, even more preferably 25 parts by mass or less, and particularly preferably 20 parts by mass or less, relative to 100 parts by mass of the base resin (A), the balance between the triazine-based compound (C) and the metal phosphinate (D) can be maintained within an appropriate range, and the above-mentioned effects can be more reliably obtained.

[0204] In determining a preferred range of the content of the metal phosphinate (D), the above-mentioned upper and lower limits of the content of the metal phosphinate (D) can be combined arbitrarily. For example, the preferred range of the content of the metal phosphinate (D) may be 1 part by mass or more and 40 parts by mass or less, 3 parts by mass or more and 30 parts by mass or less, 3 parts by mass or more and 25 parts by mass or less, or 5 parts by mass or more and 20 parts by mass or less.

[0205] As the metal phosphinate, for example, a compound represented by the following general formula (D1) can be used.

[0206]

[0207] However, R in the general formula (D1) 7 and R 8each independently represents an unsubstituted aliphatic hydrocarbon group, a substituted aliphatic hydrocarbon group, an unsubstituted aromatic hydrocarbon group, or a substituted aromatic hydrocarbon group; n represents an integer of 1 or more and 4 or less; and M represents an n-valent metal.

[0208] R 7 and R 8 The aliphatic hydrocarbon group used as may be, for example, an unsubstituted alkyl group, an alkyl group having a substituent, an unsubstituted alkenyl group, an alkenyl group having a substituent, an unsubstituted alkynyl group, or an alkynyl group having a substituent. Examples of the substituent include a halogen atom, a hydroxy group, a carboxy group, an alkoxy group, a cyano group, and an aromatic hydrocarbon group. The aromatic hydrocarbon group as the substituent is a group represented by R 7 and R 8 The aromatic hydrocarbon group is the same as the aromatic hydrocarbon group.

[0209] The number of carbon atoms in the portion excluding substituents in the aliphatic hydrocarbon group is not particularly limited, and may be 1 to 10, 1 to 5, or 1 to 3. Furthermore, the total number of carbon atoms in the aliphatic hydrocarbon group, i.e., the total number of carbon atoms in the portion excluding substituents and the number of carbon atoms in the substituents, may be 1 to 30, 3 to 20, or 6 to 15.

[0210] R 7 and R 8 The aliphatic hydrocarbon group used as is preferably an unsubstituted or substituted alkyl group, more preferably an unsubstituted or substituted ethyl group, and even more preferably an unsubstituted ethyl group.

[0211] R 7 and R 8The aromatic hydrocarbon group used as the substituent may be, for example, an unsubstituted phenyl group, a phenyl group having a substituent, an unsubstituted naphthyl group, or a naphthyl group having a substituent. Examples of the substituent include a halogen atom, a hydroxy group, a carboxy group, an alkoxy group, a cyano group, and an aliphatic hydrocarbon group. The aliphatic hydrocarbon group as the substituent may be any of the groups described above in R 7 and R 8 The aliphatic hydrocarbon group is the same as the aliphatic hydrocarbon group.

[0212] The number of carbon atoms in the portion excluding substituents in the aromatic hydrocarbon group is not particularly limited, but may be 6 to 12, or 6 to 8. Furthermore, the total number of carbon atoms in the aliphatic hydrocarbon group, i.e., the total number of carbon atoms in the portion excluding substituents and the number of carbon atoms in the substituents, may be 1 to 30, or 3 to 20, or 6 to 15.

[0213] Examples of the metal M in the general formula (D1) include lithium, sodium, potassium, calcium, magnesium, aluminum, titanium, and zinc. M in the general formula (D1) is preferably aluminum. Furthermore, n in the general formula (D1) is preferably 2 or more and 4 or less, and more preferably 3.

[0214] As the metal phosphinate (D), for example, commercially available products such as "Exolit (registered trademark) OP930," "Exolit OP935," "Exolit OP945," and "Exolit OP1230" manufactured by Clariant can also be used.

[0215] [Inorganic Filler] The adhesive composition may further contain an inorganic filler. In this case, the solder heat resistance of the adhesive composition can be further improved. The content of the inorganic filler is preferably 10 parts by mass or more and 350 parts by mass or less per 100 parts by mass of the total content of the base resin (A), the epoxy compound (B), and the triazine compound (C).

[0216] Examples of inorganic fillers include non-conductive inorganic fillers such as calcium carbonate particles, titanium oxide particles, aluminum oxide particles, zinc oxide particles, talc particles, and silica particles, and conductive inorganic fillers such as carbon black particles and conductive metal particles.

[0217] [Imidazole silane (E)] The adhesive composition may contain an imidazole silane (E) having one or more imidazole ring structures and one or more silane structures. By incorporating the imidazole silane (E) into the adhesive composition, adhesion to metals, particularly gold-plated copper foil, can be improved. This is thought to be because the silane structure and imidazole ring structure in the imidazole silane (E) exhibit high affinity with metal surfaces. It is also believed that the imidazole silane (E) acts as a curing agent for the epoxy compound (B). Therefore, it is believed that the adhesive property-improving effect can be maintained even when the adhesive composition or its cured product is heated, for example, during a reflow process.

[0218] The silane structure in the imidazole silane (E) is preferably a silyl group, and more preferably an alkoxysilyl group, which can further improve the solder heat resistance of the adhesive composition.

[0219] The imidazole ring structure in the imidazole silane (E) may have an imidazole ring having a substituent such as a saturated hydrocarbon group or an unsaturated hydrocarbon group. More specifically, the imidazole ring structure may include an imidazole ring, a 2-alkylimidazole ring, a 2,4-dialkylimidazole ring, a 4-vinylimidazole ring, or the like.

[0220] From the viewpoint of further enhancing the adhesiveness of the adhesive composition, the imidazole silane (E) is more preferably a compound represented by the following general formula (E1) or an acid adduct thereof.

[0221]

[0222] R in the general formula (E1) 9 and R 10R each independently represents a hydrogen atom, a saturated hydrocarbon group, an unsaturated hydrocarbon group, or an aryl group. 9 and R 10 The saturated hydrocarbon group, unsaturated hydrocarbon group and aryl group in the general formula (E1) may have a substituent. 11 and R 12 R each independently represents a hydrogen atom or an alkyl group. 11 At least one of R is an alkyl group. n is an integer of 1 or more and 3 or less. 9 ~R 12 The alkyl group in R preferably has 1 or more and 3 or less carbon atoms. 11 and R 12 The alkyl group in the formula (I) may have a substituent.

[0223] R in the general formula (E1) 13 represents an alkylene group or a group in which a part of the alkylene group is substituted with one or more divalent organic groups represented by the following structural formulas (E2) to (E5): 13 The alkylene group in the formula (I) preferably has 1 or more and 10 or less carbon atoms, and more preferably has 3 or more and 7 or less carbon atoms.

[0224]

[0225] R in the structural formula (E2) 14 represents a hydrogen atom or a hydroxy group. 15 represents a hydrogen atom, an alkyl group, or an aryl group. 16 and R 17 R each independently represents a hydrogen atom, an alkyl group, or an aryl group. 15 , R 16 and R 17 The alkyl group and aryl group in the formula (I) may have a substituent.

[0226] The imidazole silane (E) can be suitably synthesized, for example, by reacting an imidazole compound with a 3-glycidoxyalkylsilane compound or the like. The imidazole silane (E) may have a silanol group formed by hydrolysis of an alkoxysilyl group, or may have a polyorganosiloxane structure formed by a dehydration condensation reaction of the silanol group. The imidazole silane (E) may have both a silanol group and a polyorganosiloxane structure.

[0227] Examples of the acid to be added to the compound represented by general formula (E1) include acetic acid, lactic acid, salicylic acid, benzoic acid, adipic acid, phthalic acid, citric acid, tartaric acid, maleic acid, trimellitic acid, phosphoric acid, and isocyanuric acid. These acids may be used alone or in combination of two or more.

[0228] From the viewpoint of adhesiveness, the imidazole silane (E) is more preferably a compound represented by the following general formula (E6) or general formula (E7), or an acid adduct thereof.

[0229]

[0230] R in the general formula (E6) and the general formula (E7) 9 and R 10 R each independently represents a hydrogen atom, a saturated hydrocarbon group, an unsaturated hydrocarbon group, or an aryl group. 9 and R 10 The saturated hydrocarbon group, unsaturated hydrocarbon group and aryl group in the general formula (E6) and the general formula (E7) may have a substituent. 11 and R 12 R each independently represents a hydrogen atom or an alkyl group. 11 At least one of R is an alkyl group. n is an integer of 1 or more and 3 or less. 9 ~R 12 The alkyl group in R preferably has 1 or more and 3 or less carbon atoms. 11 and R 12 The alkyl group in the formula (I) may have a substituent.

[0231] R in the general formula (E6) and the general formula (E7) 13’ represents an alkylene group. 13’ The number of carbon atoms in the alkylene group in the general formula (E6) and the general formula (E7) is preferably 1 or more and 10 or less, and more preferably 3 or more and 7 or less. 14 represents a hydrogen atom or a hydroxy group.

[0232] More specifically, examples of the imidazole silane (E) include 1-(2-hydroxy-3-trimethoxysilylpropoxypropyl)imidazole, 1-(2-hydroxy-3-triethoxysilylpropoxypropyl)imidazole, 1-(2-hydroxy-3-tripropoxysilylpropoxypropyl)imidazole, 1-(2-hydroxy-3-tributoxysilylpropoxypropyl)imidazole, 1-(2-hydroxy-3-triethoxysilylpropoxypropyl)imidazole, 1-(2-hydroxy-3-triethoxysilylpropoxypropyl)-2-methylimidazole, 1-(2-hydroxy-3-triethoxysilylpropoxypropyl)-4-methylimidazole, 1-(3-oxo-4-trimethoxysilylpropoxypropyl)imidazole, and 1-(3-trimethoxysilylpropylamino)imidazole.

[0233] From the viewpoint of further improving the solubility of the adhesive composition in a solvent and further improving the heat resistance of a cured product of the adhesive composition, it is more preferable that the imidazole silane (E) is an acid adduct of the compound represented by general formula (E6).

[0234] The compound represented by the general formula (E6) can be easily obtained by, for example, reacting an imidazole compound with a 3-glycidoxypropylsilane compound. Examples of the imidazole compound include imidazole, 2-alkylimidazole, 2,4-dialkylimidazole, and 4-vinylimidazole. Examples of the 3-glycidoxypropylsilane compound include 3-glycidoxypropyltrialkoxysilane, 3-glycidoxypropyldialkoxyalkylsilane, and 3-glycidoxypropylalkoxydialkylsilane. Among these, the compound represented by the general formula (E6) is particularly preferably a reaction product of imidazole and 3-glycidoxypropyltrimethoxysilane.

[0235] The compound represented by the general formula (E7) can be easily obtained by reacting an imidazole compound with 3-methacryloyloxypropyltrimethoxysilane or the like.

[0236] The adhesive composition may contain one type of imidazole silane (E), or may contain two or more types of imidazole silane (E). From the viewpoint of adhesiveness, the content of the imidazole silane (E) is preferably 0.05 parts by mass or more and 20 parts by mass or less, more preferably 0.1 parts by mass or more and 10 parts by mass or less, and particularly preferably 1 part by mass or more and 5 parts by mass or less, relative to 100 parts by mass of the total content of the base resin (A) and the epoxy compound (B).

[0237] [Organic Filler] The adhesive composition may further contain an organic filler. By blending an organic filler in the adhesive composition, the solder heat resistance and moist heat resistance can be further improved. In addition, since the organic filler has excellent compatibility with the base resin (A) and the like, blending an organic filler in the liquid adhesive composition can improve the stability of the liquid.

[0238] Examples of organic fillers include (meth)acrylic resin particles, polybutadiene particles, nylon particles, polyolefin particles, polyester particles, polycarbonate particles, polyvinyl alcohol particles, polyvinyl ether particles, polyvinyl butyral particles, silicone rubber particles, polyurethane particles, phenolic resin particles, and polytetrafluoroethylene particles. The adhesive composition may contain one type of organic filler among these organic fillers, or may contain two or more types of organic fillers. From the viewpoint of further enhancing the above-mentioned effects, it is more preferable that the organic filler be one or two or more types of particles selected from the group consisting of silicone particles, polybutadiene particles, (meth)acrylic resin particles, and polyurethane particles.

[0239] The volume-based median diameter of the organic filler is not particularly limited, but from the viewpoint of improving the coatability and making it easier to adjust the coating thickness, it is preferably 0.5 μm or more and 50 μm or less, and more preferably 1 μm or more and 30 μm or less.

[0240] From the viewpoint of adhesiveness and curability, the content of the organic filler is preferably 1 part by mass or more and 50 parts by mass or less, more preferably 5 parts by mass or more and 40 parts by mass or less, and particularly preferably 10 parts by mass or more and 20 parts by mass or less, relative to 100 parts by mass of the total content of the base resin (A), the epoxy compound (B), and the triazine compound (C).

[0241] [Additives] The adhesive composition may contain additives other than the components described above, provided that the effects described above are not impaired. Examples of additives include thermoplastic resins other than the base resin (A), tackifiers, flame retardants, curing agents, curing accelerators, coupling agents, heat aging inhibitors, leveling agents, antifoaming agents, and solvents.

[0242] Examples of thermoplastic resins that can be contained in the adhesive composition include phenoxy resins, polyamide resins, polycarbonate resins, polyphenylene oxide resins, polyester resins, polyacetal resins, polyethylene-based resins, polypropylene-based resins, polyvinyl-based resins, etc. The adhesive composition may contain one type of thermoplastic resin among these thermoplastic resins, or may contain two or more types of thermoplastic resins.

[0243] Examples of tackifiers include coumarone-indene resins, terpene resins, terpene-phenol resins, rosin resins, p-t-butylphenol-acetylene resins, phenol-formaldehyde resins, xylene-formaldehyde resins, petroleum-based hydrocarbon resins, hydrogenated hydrocarbon resins, and turpentine-based resins. The adhesive composition may contain one type of tackifier from these tackifiers, or may contain two or more types of tackifiers.

[0244] As the flame retardant, organic flame retardants and inorganic flame retardants can be used. Examples of the organic flame retardant include phosphorus-based flame retardants other than metal phosphinate salts (D), such as guanidine phosphate, guanidine polyphosphate, ammonium phosphate, ammonium polyphosphate, ammonium amide phosphate, ammonium polyamide phosphate, carbamate phosphate, and carbamate polyphosphate; nitrogen-based flame retardants other than triazine-based compounds (C), such as triazole compounds, tetrazole compounds, diazo compounds, and urea; and silicon-based flame retardants such as silicone compounds and silane compounds.

[0245] Examples of inorganic flame retardants include metal hydroxides such as aluminum hydroxide, magnesium hydroxide, zirconium hydroxide, barium hydroxide, and calcium hydroxide; metal oxides such as tin oxide, aluminum oxide, magnesium oxide, zirconium oxide, zinc oxide, molybdenum oxide, and nickel oxide; metal carbonates such as zinc carbonate, magnesium carbonate, calcium carbonate, and barium carbonate; metal borides such as zinc borate; hydrated glass, etc. The adhesive composition may contain one type of these flame retardants, or may contain two or more types of flame retardants.

[0246] The curing agent is used to form a crosslinked structure by reaction with the epoxy compound (B). Examples of the curing agent include acid-based curing agents, basic active hydrogen-based curing agents, polymercaptan-based curing agents, novolac resin-based curing agents, urea resin-based curing agents, and melamine resin-based curing agents. Examples of the acid-based curing agent include amine-based curing agents (e.g., chain aliphatic diamines, chain aliphatic polyamines, alicyclic diamines, and aromatic diamines), polyamidoamine-based curing agents, chain aliphatic polycarboxylic acids, alicyclic polycarboxylic acids, aromatic polycarboxylic acids, and acid anhydrides thereof.

[0247] Examples of the chain aliphatic diamine curing agent include ethylenediamine, 1,3-diaminopropane, 1,4-diaminobutane, hexamethylenediamine, polymethylenediamine, polyetherdiamine, 2,5-dimethylhexamethylenediamine, and trimethylhexamethylenediamine.

[0248] Examples of the chain aliphatic polyamine curing agent include diethylenetriamine, iminobis(hexamethylene)triamine, trihexatetramine, tetraethylenepentamine, aminoethylethanolamine, tri(methylamino)hexane, dimethylaminopropylamine, diethylaminopropylamine, and methyliminobispropylamine.

[0249] Examples of alicyclic diamine curing agents include menthenediamine, isophoronediamine, bis(4-amino-3-methyldicyclohexyl)methane, diaminodicyclohexylmethane, bis(aminomethyl)cyclohexane, N-ethylaminopiperazine, 3,9-bis(3-aminopropyl)2,4,8,10-tetraoxaspiro[5.5]undecane, and hydrogenated metaxylylenediamine.

[0250] Examples of aromatic diamine curing agents include metaphenylenediamine, diaminodiphenylmethane, diaminodiphenylsulfone, diaminodiethyldiphenylmethane, and metaxylylenediamine.

[0251] Examples of the chain aliphatic polycarboxylic acid curing agent and the acid anhydride curing agent include succinic acid, adipic acid, dodecenyl succinic anhydride, polyadipic anhydride, polyazelaic anhydride, and polysebacic anhydride.

[0252] Examples of alicyclic polycarboxylic acid curing agents and acid anhydride curing agents include methyltetrahydrophthalic acid, methylhexahydrophthalic acid, methylhimic acid, hexahydrophthalic acid, tetrahydrophthalic acid, trialkyltetrahydrophthalic acid, methylcyclodicarboxylic acid, and acid anhydrides thereof.

[0253] Examples of aromatic polycarboxylic acid curing agents and acid anhydride curing agents include phthalic acid, trimellitic acid, pyromellitic acid, benzophenone tetracarboxylic acid, ethylene glycol glycol bistrimellitic acid, glycerol tristrimellitic acid, and acid anhydrides thereof.

[0254] Examples of basic active hydrogen curing agents include dicyandiamide and organic acid dihydrazide. Examples of polymercaptan curing agents include mercaptoated epoxy resins and mercaptopropionic acid esters. Examples of novolac resin curing agents include phenol novolac curing agents and cresol novolac curing agents.

[0255] The adhesive composition may contain one type of curing agent from the above-mentioned curing agents, or may contain two or more types of curing agents. From the viewpoint of further improving adhesiveness and heat resistance, the functional group equivalent of the curing agent in the adhesive composition is preferably 0.2 molar equivalents or more and 2.5 molar equivalents or less, and more preferably 0.4 molar equivalents or more and 2.0 molar equivalents or less, relative to 1 molar equivalent of the epoxy group of the epoxy compound (B).

[0256] The curing accelerator is a component used for the purpose of accelerating the reaction of the epoxy compound (B). Examples of the curing accelerator that can be used include tertiary amine curing accelerators, tertiary amine salt curing accelerators, and imidazole curing accelerators.

[0257] Examples of tertiary amine curing accelerators include benzyldimethylamine, 2-(dimethylaminomethyl)phenol, 2,4,6-tris(dimethylaminomethyl)phenol, tetramethylguanidine, triethanolamine, N,N'-dimethylpiperazine, triethylenediamine, and 1,8-diazabicyclo[5.4.0]undecene.

[0258] Examples of the tertiary amine salt curing accelerator include formate, octylate, p-toluenesulfonate, o-phthalate, phenolate, and phenol novolac resin salt of 1,8-diazabicyclo[5.4.0]undecene; and formate, octylate, p-toluenesulfonate, o-phthalate, phenolate, and phenol novolac resin salt of 1,5-diazabicyclo[4.3.0]nonene.

[0259] Examples of the imidazole curing accelerator include 2-methylimidazole, 2-undecylimidazole, 2-heptadecylimidazole, 1,2-dimethylimidazole, 2-methyl-4-ethylimidazole, 2-phenylimidazole, 2-phenyl-4-methylimidazole, 1-benzyl-2-methylimidazole, 1-benzyl-2-phenylimidazole, 2,4-diamino-6-[2'-methylimidazolyl-(1')]-ethyl-s-triazine, 2,4-diamino-6-[2' -undecylimidazolyl-(1')]-ethyl-s-triazine, 2,4-diamino-6-[2'-ethyl-4'-methylimidazolyl-(1')]-ethyl-s-triazine, 2,4-diamino-6-[2'-methylimidazolyl-(1')]-ethyl-s-triazine isocyanuric acid adduct, 2-phenylimidazole isocyanuric acid adduct, 2-phenyl-4,5-dihydroxymethylimidazole, and 2-phenyl-4-methyl-5-hydroxymethylimidazole.

[0260] The adhesive composition may contain one type of curing accelerator among the above-mentioned curing accelerators, or may contain two or more types of curing accelerators. From the viewpoints of adhesiveness and heat resistance, the content of the curing accelerator is preferably 1 part by mass or more and 10 parts by mass or less, and more preferably 2 parts by mass or more and 5 parts by mass or less, per 100 parts by mass of the epoxy compound (B).

[0261] Examples of coupling agents include silane coupling agents, titanate coupling agents, aluminate coupling agents, and zirconium coupling agents. Examples of silane coupling agents include vinyltrimethoxysilane, 3-glycidoxypropyltrimethoxysilane, p-styryltrimethoxysilane, 3-methacryloxypropylmethyldimethoxysilane, 3-acryloxypropyltrimethoxysilane, N-2-(aminoethyl)-3-aminopropylmethyldimethoxysilane, 3-ureidopropyltriethoxysilane, 3-mercaptopropylmethyldimethoxysilane, bis(triethoxysilylpropyl)tetrasulfide, 3-isocyanatopropyltriethoxysilane, and imidazole silane. The adhesive composition may contain one of these coupling agents, or two or more of them.

[0262] Examples of the heat aging inhibitor include phenol-based antioxidants, sulfur-based antioxidants, and phosphorus-based antioxidants. Examples of the phenol-based antioxidant include 2,6-di-tert-butyl-4-methylphenol, n-octadecyl-3-(3',5'-di-tert-butyl-4'-hydroxyphenyl)propionate, and tetrakis[methylene-3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate]methane.

[0263] Examples of sulfur-based antioxidants include dilauryl-3,3'-thiodipropionate and dimyristyl-3,3'-dithiopropionate. Examples of phosphorus-based antioxidants include trisnonylphenyl phosphite and tris(2,4-di-tert-butylphenyl)phosphite. The adhesive composition may contain one type of heat-aging inhibitor from these heat-aging inhibitors, or may contain two or more types of heat-aging inhibitors.

[0264] It is preferable that the adhesive composition further contains a solvent. In this case, a liquid adhesive composition can be obtained. By making the adhesive composition liquid, it is possible to smoothly apply the adhesive composition to an adherend and form an adhesive layer, and it is possible to easily form an adhesive layer of a desired thickness. More specifically, the liquid adhesive composition may be a solution in which solids are dissolved in a solvent, or a dispersion in which solids are dispersed in a solvent.

[0265] Examples of the solvent include alcohol-based solvents, ketone-based solvents, aromatic hydrocarbon-based solvents, ester-based solvents, and aliphatic hydrocarbon-based solvents. Examples of the alcohol-based solvent include methanol, ethanol, isopropyl alcohol, n-propyl alcohol, isobutyl alcohol, n-butyl alcohol, benzyl alcohol, ethylene glycol monomethyl ether, propylene glycol monomethyl ether, diethylene glycol monomethyl ether, and diacetone alcohol.

[0266] Examples of ketone solvents include acetone, methyl ethyl ketone, methyl isobutyl ketone, methyl amyl ketone, cyclohexanone, and isophorone. Examples of aromatic hydrocarbon solvents include toluene, xylene, ethylbenzene, and mesitylene. Examples of ester solvents include methyl acetate, ethyl acetate, ethylene glycol monomethyl ether acetate, and 3-methoxybutyl acetate. Examples of aliphatic hydrocarbon solvents include hexane, heptane, cyclohexane, and methylcyclohexane. The adhesive composition may contain one or more of these solvents.

[0267] The base resin (A) has the property of being easily soluble in protic solvents. Therefore, from the viewpoint of more easily dissolving the base resin (A) in a solvent, it is preferable that the adhesive composition contains an alcohol-based solvent. When the adhesive composition contains a solvent, from the viewpoint of workability including film-forming ability, the solids concentration of the adhesive composition is preferably 3% by mass or more and 80% by mass or less, and more preferably 10% by mass or more and 50% by mass or less.

[0268] [Method of Using the Adhesive Composition] The method of using the adhesive composition is not particularly limited, and the adhesive composition can be used in various embodiments. For example, the adhesive composition can be used as an adhesive for bonding two adherends. Furthermore, for example, a laminate containing a cured product of the adhesive composition can be obtained by applying the adhesive composition to the surface of an adherend and then curing it. The adherend to which the adhesive composition is applied may be made of a metal material such as copper, aluminum, or stainless steel, or may be made of a polymer material such as a polyimide resin, polyether ether ketone resin, polyphenylene sulfide resin, modified polyimide resin, or liquid crystal polymer. The shape of the adherend is not particularly limited, and various embodiments are possible. More detailed uses of the adhesive composition will be described later.

[0269] (Bonding Film) A bonding film can be obtained by providing an uncured product of the adhesive composition or a semi-cured product obtained by partially curing the adhesive composition on a release film. The bonding film has an adhesive layer and a release film provided on one or both sides of the adhesive layer and configured to be peelable from the adhesive layer. The adhesive layer in the bonding film is composed of the adhesive composition or a semi-cured product obtained by partially curing the adhesive composition.

[0270] The bonding film has an adhesive layer composed of an uncured adhesive composition or a semi-cured product of the adhesive composition. The adhesive layer is provided on a release film. Therefore, after the adhesive layer is attached to an adherend, the release film can be peeled off from the adhesive layer, and another adherend can be attached to the adhesive layer. Furthermore, because the adhesive layer is composed of an uncured or semi-cured product of the adhesive composition, the curing reaction can be further promoted by heating or the like. Therefore, two adherends can be bonded by curing the adhesive layer while the adhesive layer is interposed between them.

[0271] Furthermore, as mentioned above, the cured product of the adhesive composition exhibits excellent heat resistance even when hygroscopic, and can suppress peeling of the adherend after heating. Therefore, with the bonding film, even when two adherends are bonded together while the adherends or adhesive layer are not sufficiently dry, peeling of the cured product from the adherend can be suppressed when heated. Bonding films with such properties are suitable for the production of FPCs and FPC-related products.

[0272] The release film in the bonding film is configured so that it can be peeled off from the adhesive layer without damaging the adhesive layer. Examples of the release film include polyethylene terephthalate film, polyethylene film, polypropylene film, silicone release-treated paper, polyolefin resin-coated paper, polymethylpentene (TPX) film, and fluorine-based resin film. The thickness of the release film is preferably 20 μm or more and 100 μm or less.

[0273] The thickness of the adhesive layer is preferably 5 μm or more and 100 μm or less, more preferably 5 μm or more and 70 μm or less, even more preferably 5 μm or more and 50 μm or less, and particularly preferably 10 μm or more and 40 μm or less. The adhesive layer preferably does not substantially contain a solvent. The term "adhesive layer substantially free of solvent" includes both a state in which the adhesive layer does not contain any solvent at all and a state in which the adhesive layer contains a solvent to the extent that it does not interfere with maintaining the shape of the adhesive layer and attaching it to the adherend.

[0274] The method for producing the bonding film is not particularly limited, and known methods can be appropriately adopted. For example, when producing a bonding film using an adhesive composition containing a solvent, the adhesive composition is applied to the surface of a release film, and then at least a portion of the solvent is removed from the adhesive composition on the release film to form an adhesive layer on the release film, thereby obtaining a bonding film. The method for applying the adhesive composition to the release film may be selected from known application methods such as gravure coating, kiss coating, die coating, lip coating, comma coating, blade coating, roll coating, knife coating, spray coating, bar coating, spin coating, and dip coating.

[0275] The method for removing the solvent from the adhesive composition is not particularly limited, and can be, for example, a method of drying the adhesive composition by various heating methods such as hot air drying, far-infrared heating, high-frequency induction, etc. In this case, the drying temperature for the adhesive composition is preferably 40°C or higher and 250°C or lower, and more preferably 70°C or higher and 170°C or lower.

[0276] (Laminate with adhesive layer) A laminate with an adhesive layer can be obtained by providing an uncured or semi-cured product of the adhesive composition on a substrate layer. The laminate with an adhesive layer has an adhesive layer and a substrate layer adhered to at least one surface of the adhesive layer. The adhesive layer in the laminate with an adhesive layer is composed of the adhesive composition or a semi-cured product obtained by partially curing the adhesive composition.

[0277] The laminate with an adhesive layer has an adhesive layer made of an uncured adhesive composition or a semi-cured product of the adhesive composition. The adhesive layer is provided on a substrate layer. Therefore, after the adhesive layer is attached to the adherend, the adhesive layer can be further cured to bond the laminate with the adhesive layer to the adherend.

[0278] Furthermore, as described above, the adhesive composition can suppress peeling of the adherend after heating even when the adhesive composition is insufficiently dried. Therefore, with the laminate with the adhesive layer, even when the adherend or the adhesive layer is bonded in an insufficiently dried state, peeling of the adherend from the cured product can be suppressed when the cured product is heated. A laminate with an adhesive layer having such properties is suitable for the production of FPCs and FPC-related products.

[0279] The substrate layer in the adhesive layer-attached laminate is preferably a resin film, more preferably an electrically insulating resin film. Examples of resins that can be used to form the resin film include polyimide resins, modified polyimide resins, mixed resins of polyimide resins and modified polyimide resins, liquid crystal polymers, and fluorine-based resins. Among these, the resin that forms the resin film is preferably a polyimide resin, modified polyimide resin, or mixed resins of polyimide resins and modified polyimide resins, more preferably a polyimide resin. The resin film may also contain additives as needed. The surface of the substrate layer to which the adhesive layer is attached may be surface-treated. A laminate with an adhesive layer, which includes an electrically insulating resin film and an electrically insulating adhesive layer provided on the resin film, is sometimes called a coverlay film.

[0280] The thickness of the substrate layer and the thickness of the adhesive layer in the laminate with an adhesive layer may be appropriately set depending on the application of the laminate with an adhesive layer. For example, from the viewpoint of improving the electrical properties of the laminate with an adhesive layer, it is preferable to make the thickness of the substrate layer thin. For example, the thickness of the substrate layer is preferably 3 μm or more and 125 μm or less.

[0281] Furthermore, the thickness of the adhesive layer in the laminate with the adhesive layer is preferably 5 μm or more and 100 μm or less, more preferably 5 μm or more and 70 μm or less, even more preferably 5 μm or more and 50 μm or less, and particularly preferably 10 μm or more and 40 μm or less.

[0282] The ratio of the thickness of the adhesive layer to the thickness of the base layer is preferably from 1 to 10, and more preferably from 1 to 5. Furthermore, the thickness of the adhesive layer is preferably greater than the thickness of the base layer.

[0283] The laminate with the adhesive layer may have a release film on the adhesive layer, if necessary. The release film provided on the adhesive layer is the same as the release film used in the bonding film described above.

[0284] The method for producing the laminate with an adhesive layer is the same as the method for producing the bonding film described above. That is, for example, when producing the laminate with an adhesive layer using an adhesive composition containing a solvent, the adhesive composition is applied to the surface of the base layer, and then at least a part of the solvent is removed from the adhesive composition on the base layer to form an adhesive layer on the base layer, thereby obtaining the laminate with the adhesive layer.

[0285] (Laminate) The adhesive composition can also be used to produce a laminate containing a cured product of the adhesive composition. The laminate has a cured product layer made of the cured product of the adhesive composition. The thickness of the cured product layer can be appropriately set depending on the application of the laminate. The thickness of the cured product layer is preferably 5 μm or more and 100 μm or less, more preferably 5 μm or more and 70 μm or less, even more preferably 5 μm or more and 50 μm or less, and particularly preferably 10 μm or more and 40 μm or less.

[0286] The laminate may be a flexible copper-clad laminate including a resin film, a cured product layer provided on at least one side of the resin film, and a copper foil provided on the cured product layer. The adhesive composition has excellent adhesion to copper-containing articles. Therefore, a flexible copper-clad laminate obtained using the adhesive composition has excellent durability and the copper foil is less likely to peel off.

[0287] The resin film in the flexible copper-clad laminate may be composed of, for example, a polyimide resin, a modified polyimide resin, a mixed resin of a polyimide resin and a modified polyimide resin, a liquid crystal polymer, a fluorine-based resin, etc. Among these resins, the resin film is preferably composed of a polyimide resin, a modified polyimide resin, or a mixed resin of a polyimide resin and a modified polyimide resin. The copper foil in the flexible copper-clad laminate may be an electrolytic copper foil or a rolled copper foil. The copper foil may also be plated with other metals or alloys. The thickness of the cured layer in the flexible copper-clad laminate is preferably 5 μm or more and 50 μm or less, and more preferably 10 μm or more and 40 μm or less.

[0288] The method for producing the laminate is not particularly limited, and known methods can be appropriately adopted. For example, when a laminate including a first adherend and a second adherend is produced using a solvent-containing adhesive composition, the adhesive composition is applied to the surface of the first adherend, and then the adhesive composition is dried to form an adhesive layer on the first adherend. Next, the surface of the adhesive layer and the second adherend are brought into surface contact, and lamination is performed at a temperature of, for example, 80°C or higher and 150°C or lower. This allows for the production of a laminate including the first adherend, the adhesive layer provided on the first adherend, and the second adherend provided on the adhesive layer.

[0289] The laminate is then heated and pressed to cure the adhesive layer, forming a cured layer. The conditions for performing the heat press are not particularly limited as long as they can bond the adhesive layer to the adherend. For example, the heating temperature in the heat press can be appropriately set within a range of 150°C or higher and 200°C or lower. The pressure in the heat press can be appropriately set within a range of 1 MPa or higher and 3 MPa or lower. The pressing time in the heat press can be appropriately set within a range of 1 minute or higher and 60 minutes or lower.

[0290] After the heat pressing, the laminate may be heated as needed to perform after-curing, further hardening the adhesive layer. The heating temperature during after-curing may be appropriately set, for example, within the range of 100° C. to 200° C. The heating time during after-curing may be appropriately set, for example, within the range of 30 minutes to 4 hours.

[0291] Examples of the adhesive composition are described below. In these examples, the adhesive composition was prepared using the following raw materials.

[0292] (Base Resin (A)) In this example, polyamide a1, polyester polyamide a2, polyester polyurethane a3, a4, and polyurethane a5, a6 were used as the base resin (A). These were prepared by the following methods.

[0293] [Polyamide a1] 485 parts by mass of dimer acid, 100 parts by mass of hexamethylenediamine, and 120 parts by mass of distilled water were placed in a flask equipped with a stirrer, a reflux dehydrator, and a distillation tube. The flask was heated, and the temperature of the contents was raised to 120°C to distill off water. The temperature of the contents was then raised to 240°C at a rate of 20°C / hour. This temperature was maintained for 3 hours to continue the reaction, yielding polyamide a1 in pellet form. The amine value of polyamide a1 was 4.5 mgKOH / g. The amine value of the polyamide was measured and calculated by potentiometry in accordance with JIS K 7237 (1995).

[0294] [Polyester Polyamide a2] 7 parts by weight of dimer acid, 406 parts by weight of azelaic acid, 364 parts by weight of isophorone diamine, and 120 parts by weight of distilled water were placed in a flask equipped with a stirrer, a reflux dehydrator, and a distillation column. The flask was heated, and the temperature of the contents was increased to 120°C to distill off water. The flask was then further heated, and the temperature of the contents was increased to 240°C at a rate of 20°C / hour. After maintaining this temperature for 1 hour, 200 parts by weight of azelaic acid, 125 parts by weight of neopentyl glycol, and 2.1 parts by weight of tetrabutoxy titanate as an esterification catalyst were added to the reaction product in the flask. The addition of these raw materials caused the temperature of the contents of the flask to decrease to 150°C.

[0295] The flask was then heated again to raise the temperature of the contents to 220°C. The reaction was continued by maintaining this temperature until the amine value reached 7.6 mgKOH / g. Thus, polyester polyamide a2 in pellet form was obtained. The acid value of polyester polyamide a2 was 1.3 mgKOH / g. The acid value of the resin in this example was measured and calculated by potentiometric titration in accordance with JIS K 2501 (2003).

[0296] [Polyester Polyurethane a3] 600 parts by mass of a polyester adhesive ("PES-360HVXM30" manufactured by Toagosei Co., Ltd.), 100 parts by mass of toluene, and 20 parts by mass of neopentyl glycol were placed in a flask equipped with a stirrer, a reflux dehydration apparatus, and a distillation tube. The flask was heated to raise the temperature of the contents to 120°C, and 100 parts by mass of the solvent containing water was distilled off, after which the temperature of the contents was lowered to 105°C. Thereafter, 0.4 parts by mass of 2,2-dimethylolpropionic acid was added to the flask and dissolved in the contents.

[0297] Next, 34 parts by mass of hexamethylene diisocyanate was added to the flask. 30 minutes after the addition of hexamethylene diisocyanate, 0.2 parts by mass of dibutyltin dilaurate was added to the flask, and the reaction was continued for 6 hours. The contents of the flask were then diluted with toluene and 2-propanol to adjust the solids concentration to 30% by mass. This yielded a solution containing polyester polyurethane a3. The polyester polyurethane a3 had a number average molecular weight of 36,000 and an acid value of 2 mgKOH / g.

[0298] [Polyester Polyurethane a4] 600 parts by mass of a polyester adhesive ("PES-360HVXM30" manufactured by Toagosei Co., Ltd.), 100 parts by mass of toluene, and 30 parts by mass of 2-butyl-2-ethyl-1,3-propanediol were placed in a flask equipped with a stirrer, a reflux dehydrator, and a distillation tube. The flask was heated to raise the temperature of the contents to 120°C, and 100 parts by mass of the solvent containing water was distilled off, after which the temperature of the contents was lowered to 105°C. Thereafter, 0.4 parts by mass of 2,2-bis(hydroxymethyl)propionic acid was added to the flask and dissolved in the contents.

[0299] Next, 42 parts by mass of norbornane diisocyanate ("Cosmonate (registered trademark) NBDI (registered trademark)" manufactured by Mitsui Chemicals, Inc.) was added to the flask, and 30 minutes after the addition of the norbornane diisocyanate, 0.2 parts by mass of dibutyltin dilaurate was added to the flask. The reaction was then continued until a predetermined molecular weight was reached, and the contents of the flask were then diluted with toluene and 2-propanol to adjust the solids concentration to 30% by mass. This yielded a solution containing polyester polyurethane a4. The polyester polyurethane a4 had a number average molecular weight of 35,000 and an acid value of 2 mgKOH / g.

[0300] [Polyurethane a5] 100 parts by mass of polyphenylene ether diol ("Noryl SA90" manufactured by SABIC), 8 parts by mass of 2-butyl-2-ethyl-1,3-propanediol, and 230 parts by mass of toluene were placed in a flask equipped with a stirrer, a reflux dehydration apparatus, and a distillation column. The flask was heated to raise the temperature of the contents to 120°C, and 100 parts by mass of the solvent containing water was distilled off, after which the temperature of the contents was lowered to 105°C. Thereafter, 0.8 parts by mass of 2,2-bis(hydroxymethyl)propionic acid was added to the flask and dissolved in the contents.

[0301] Next, 22 parts by mass of 1,3-bis(isocyanatomethyl)cyclohexane was added to the flask. 30 minutes after the addition of 1,3-bis(isocyanatomethyl)cyclohexane, 0.1 parts by mass of dibutyltin dilaurate was added to the flask, and the reaction was continued for 12 hours. The contents of the flask were then diluted with a mixed solvent of 30 parts by mass of toluene, 30 parts by mass of methyl ethyl ketone, and 15 parts by mass of 2-propanol. This yielded a solution containing polyurethane a5. Polyurethane a5 had a weight-average molecular weight of 77,000, a number-average molecular weight of 13,000, and an acid value of 2.6 mgKOH / g.

[0302] [Polyurethane a6] 90 parts by mass of polyphenylene ether diol ("Noryl SA90" manufactured by SABIC), 10 parts by mass of polycarbonate diol ("ETERNACOLL (registered trademark) UH-100" manufactured by UBE Corporation), 8 parts by mass of 2-butyl-2-ethyl-1,3-propanediol, and 230 parts by mass of toluene were placed in a flask equipped with a stirrer, a reflux dehydration apparatus, and a distillation column. The flask was heated to raise the temperature of the contents to 120°C, and 100 parts by mass of the solvent containing water was distilled off, and then the temperature of the contents was lowered to 105°C. Thereafter, 0.8 parts by mass of 2,2-bis(hydroxymethyl)propionic acid was added to the flask and dissolved in the contents.

[0303] Next, 22 parts by mass of 1,3-bis(isocyanatomethyl)cyclohexane was added to the flask. 30 minutes after the addition of 1,3-bis(isocyanatomethyl)cyclohexane, 0.1 parts by mass of dibutyltin dilaurate was added to the flask, and the reaction was continued for 12 hours. The contents of the flask were then diluted with a mixed solvent of 30 parts by mass of toluene, 30 parts by mass of methyl ethyl ketone, and 15 parts by mass of 2-propanol. Polyurethane a6 was thus obtained. Polyurethane a6 had a weight-average molecular weight of 83,000, a number-average molecular weight of 11,000, and an acid value of 2.6 mgKOH / g.

[0304] (Epoxy Compound (B)) The epoxy compounds (B) used in this example are as follows. Epoxy compound b1: trisphenolmethane type epoxy resin ("jER (registered trademark) 1032H60" manufactured by Mitsubishi Chemical Corporation) Epoxy compound b2: bisphenol A novolac type epoxy resin ("EPICLON (registered trademark) N-865" manufactured by DIC Corporation) Epoxy compound b3: bisphenol A type epoxy resin ("jER 1055" manufactured by Mitsubishi Chemical Corporation) Epoxy compound b4: cresol novolac type epoxy resin ("EPICLON N-665-EXP" manufactured by DIC Corporation)

[0305] (Triazine-based Compound (C)) The triazine-based compounds (C) used in this example are as follows: Triazine-based compound c1: melamine-melam-melem polyphosphate double salt ("PHOSMEL (registered trademark)-200" manufactured by Nissan Chemical Industries, Ltd.) Triazine-based compound c2: melamine polyphosphate ("MPP-A" manufactured by Sanwa Chemical Co., Ltd.) Triazine-based compound c3: melamine cyanurate ("MC-6000" manufactured by Nissan Chemical Industries, Ltd.)

[0306] Triazine-based compound c4: melamine Triazine-based compound c5: cyanuric acid Triazine-based compound c6: acetoguanamine Triazine-based compound c7: benzoguanamine Triazine-based compound c8: trithiocyanuric acid

[0307] The median diameters on a volume basis of the triazine-based compounds (C) used in the present examples are as shown in Tables 1 and 2.

[0308] (Metal Phosphinate (D)) The metal phosphinate (D) used in this example is as follows: Metal phosphinate d1: "Exolit OP935" manufactured by Clariant

[0309] (Other compounds) Phosphazene: "SPB-100" manufactured by Otsuka Chemical Co., Ltd.

[0310] Examples 1 to 21 and Comparative Examples 1 to 4 The raw materials described above were added to a flask equipped with a stirrer in the proportions shown in Tables 1 and 2, and a mixed solvent of toluene, methyl ethyl ketone, and isopropanol was added to the flask so that the solid content of the contents was approximately 20% by mass. The blending amount of base resin (A) in Tables 1 and 2 is the solid content, i.e., the amount of base resin (A) excluding the solvent. The ratio of toluene, methyl ethyl ketone, and isopropanol in the mixed solvent was adjusted appropriately depending on the solubility of base resin (A).

[0311] The flask was then heated to raise the temperature of the contents to 60°C. The contents of the flask were then stirred for 6 hours while maintaining the temperature, thereby dispersing the base resin (A) and the epoxy compound (B) in the solvent, as well as the triazine compound (C) and the metal phosphinate (D). A liquid adhesive composition was thus prepared. The "Phosphorus Atom Content" column in Tables 1 and 2 lists the solids content of the adhesive composition, i.e., the ratio (unit: mass%) of phosphorus atoms contained in the adhesive composition to the total blend amount of the base resin (A), the epoxy compound (B), the triazine compound (C), the metal phosphinate (D), and the phosphazene.

[0312] Next, using the adhesive compositions of the Examples and Comparative Examples, a test piece A for evaluating flame retardancy (hereinafter referred to as "test piece A"), a bonding film B, and a test piece C for evaluating adhesion (hereinafter referred to as "test piece C") were prepared by the following methods.

[0313] [Flame Retardancy Evaluation Specimen A] As shown in Fig. 1, the flame retardancy evaluation specimen A has a cured material layer 1 made of a cured product of the adhesive composition and polyimide films 2 (2a, 2b) laminated on both sides of the cured material layer 1. The thickness of the cured material layer 1 is 15 µm, and the thickness of the polyimide film 2 is 25 µm.

[0314] The test piece A was prepared as follows: First, the adhesive composition was applied with a roll coater to the surface of the first polyimide film 2a of the two polyimide films 2. The adhesive composition on the polyimide film 2a was then dried for 3 minutes in an oven set at 100°C, thereby preparing a coverlay film having the polyimide film 2a and an adhesive layer laminated on the polyimide film 2a.

[0315] Next, a second polyimide film 2b was superimposed on the adhesive layer of the coverlay film, and a thermal lamination process was performed. The heating temperature in the thermal lamination process was 120°C, the pressure was 0.4 MPa, and the lamination speed was 0.5 m / min. The laminate of the coverlay film and the polyimide film 2b was then subjected to a heat press process under conditions of a temperature of 170°C, a pressure of 3 MPa, and a heating time of 30 minutes, thereby curing the adhesive layer to form a cured layer 1 and bonding the cured layer 1 and the polyimide film 2b together. The laminate thus obtained was cut to a predetermined size to obtain test piece A.

[0316] [Bonding Film B] As shown in FIG. 2, bonding film B has a release film 3 and an adhesive layer 10 provided on the release film 3. The release film 3 is made of polyethylene terephthalate. The release film 3 has a thickness of 35 μm. The adhesive layer 10 has a thickness of 25 μm. The adhesive layer 10 is made of an adhesive composition 100 or a semi-cured product thereof.

[0317] The bonding film B is obtained by applying the adhesive composition onto the release film 3 with a roll coater and then drying it at a temperature of 100° C. for 3 minutes.

[0318] [Test Piece C for Adhesion Evaluation] As shown in FIG. 3 , the test piece C for adhesion evaluation has a copper-clad laminate 4 composed of a polyimide film 41 and a copper foil 42 laminated on the polyimide film 41, a cured material layer 1 provided on the polyimide film 41 of the copper-clad laminate 4, and a copper foil 5 provided on the cured material layer 1. The polyimide film 41 and the copper foil 5 of the copper-clad laminate 4 are bonded via the cured material layer 1. The thickness of the polyimide film 41 constituting the copper-clad laminate 4 is 25 μm, and the thickness of the copper foil 42 is 18 μm. The thickness of the cured material layer 1 is 15 μm. A rolled copper foil with a thickness of 35 μm was used as the copper foil 5.

[0319] The test piece C was prepared as follows: First, the adhesive composition was applied to the polyimide film 41 of the copper-clad laminate 4 using a roll coater. Then, the adhesive composition on the copper-clad laminate 4 was dried for 3 minutes in an oven set at a temperature of 100°C, thereby forming an adhesive layer on the polyimide film 41.

[0320] Next, copper foil 5 was superimposed on the adhesive layer and subjected to a thermal lamination treatment. The heating temperature in the thermal lamination treatment was 120°C, the pressure was 0.4 MPa, and the lamination speed was 0.5 m / min. Thereafter, the laminate of the copper-clad laminate 4, the adhesive layer, and the copper foil 5 was subjected to a hot press treatment under conditions of a temperature of 170°C, a pressure of 3 MPa, and a heating time of 30 minutes, thereby curing the adhesive layer to form a cured material layer 1 and bonding the cured material layer 1 to the copper foil 5. The flexible copper-clad laminate thus obtained was cut to a predetermined size to obtain test piece C.

[0321] Using the test pieces A and C obtained as described above, the various properties shown in Tables 1 and 2 were evaluated. The evaluation methods for each property were as follows.

[0322] (Peel Adhesion Strength) Test piece C shown in FIG. 3 was used to measure peel adhesion strength. The peel adhesion strength was measured in accordance with JIS C 6481 "Test Methods for Copper-Clad Laminates for Printed Wiring Boards." In this example, the peel adhesion strength of test piece C in its initial state was measured. More specifically, in measuring the peel adhesion strength in its initial state, test piece C prepared by the above-mentioned method was used, and the 180° peel adhesion strength (unit: N / cm) was measured when peeling the copper foil 5 from the copper-clad laminate 4. The temperature during measurement was 23°C, and the pulling speed was 50 mm / min. The peel adhesion strength of test piece C in its initial state was as shown in Tables 1 and 2.

[0323] (Heat Resistance) Test pieces C with different moisture absorption states were prepared, and the heat resistance was evaluated based on the peel adhesive strength after heating these test pieces. Specifically, test pieces C in their initial state were prepared as test pieces C in a state that did not absorb moisture. In addition, two types of test pieces were prepared as test pieces in a moisture-absorbed state: test piece C that had been stored in a thermo-hygrostat chamber at a temperature of 40°C and a relative humidity of 90% RH for 24 hours to absorb moisture, and test piece C that had been stored in a thermo-hygrostat chamber at a temperature of 40°C and a relative humidity of 90% RH for 72 hours to absorb moisture.

[0324] These three types of test specimens C were heated in a drying oven at a temperature of 260°C for 10 minutes. After heating was completed, the test specimens C were removed from the drying oven and their peel bond strengths were measured using the same method as for measuring the peel bond strength of the initial test specimens C. Then, using the peel bond strength of the initial test specimens C and the peel bond strength of the heated test specimens, the peel bond strength retention rates after heating were calculated for the initial test specimens C, the test specimens C after 24 hours of moisture absorption, and the test specimens C after 72 hours of moisture absorption. Specifically, the peel bond strength retention rates after heating are the ratios, expressed as a percentage, of the peel bond strength of the heated test specimens C to the peel bond strength of the initial test specimens C.

[0325] In the "Heat Resistance" column of Tables 1 and 2, the symbol "A" was entered when the peel adhesion strength retention rate of each test piece C was 80% or more, the symbol "B" was entered when it was 60% or more but less than 80%, the symbol "C" was entered when it was 30% or more but less than 60%, and the symbol "D" was entered when it was less than 30%.

[0326] (Flame Retardancy) Using test piece A shown in Figure 1, flame retardancy was evaluated by a method in accordance with UL 94. In the "Flame Retardancy" column of Tables 1 and 2, "Good" was recorded when the flame retardancy based on UL 94 was judged to be VTM-0, and "Poor" was recorded when it was judged to be VTM-1 or less.

[0327]

[0328]

[0329] As shown in Tables 1 and 2, the adhesive compositions of Examples 1 to 21 contained the base resin (A), epoxy compound (B), triazine compound (C), and metal phosphinate (D) in the above-mentioned specific ratios. Therefore, the cured products of these adhesive compositions exhibited high heat resistance even in a humidified state, and were able to suppress a decrease in peel bond strength even when heated after 24 hours of humidification or after 72 hours of humidification.

[0330] Furthermore, among Examples 1 to 21, when Examples 8 to 21, which have roughly the same composition except that the base resin (A) is polyamide a2 and the type of triazine-based compound (C) is different, are compared, the peel bond strength retention rate after 24 hours of moisture absorption in Examples 8 to 14 is higher than that of Examples 15 to 21. These comparisons show that by using a triazine-based compound (C) that contains melamine in its molecular structure and has a median diameter of 10 μm or less, the heat resistance of the cured product in a moisture-absorbed state can be further improved.

[0331] In contrast, the adhesive composition of Comparative Example 1 does not contain the triazine compound (C) or the metal phosphinate (D). Therefore, the cured product of the adhesive composition of Comparative Example 1 has poor heat resistance after moisture absorption and low peel bond strength retention after moisture absorption for 24 hours and 72 hours.

[0332] The content of the triazine compound (C) in the adhesive composition of Comparative Example 2 is lower than the above-mentioned specific range. Furthermore, the adhesive composition of Comparative Example 2 does not contain a metal phosphinate (D). Therefore, the cured product of the adhesive composition of Comparative Example 2 has poor heat resistance after moisture absorption and low peel bond strength retention after 24 hours of moisture absorption and after 72 hours of moisture absorption.

[0333] The adhesive composition of Comparative Example 3 contains a metal phosphinate (D), but the content of the triazine compound (C) is lower than the above-mentioned specific range. Therefore, the cured product of the adhesive composition of Comparative Example 3 has poor heat resistance after moisture absorption and low peel bond strength retention after 24 hours and 72 hours of moisture absorption.

[0334] The adhesive composition of Comparative Example 4 contains phosphazene instead of the metal phosphinate (D). Therefore, although the cured product of the adhesive composition of Comparative Example 4 has excellent flame retardancy, it has poor heat resistance after moisture absorption and exhibits low peel bond strength retention after moisture absorption for 24 hours and 72 hours.

[0335] The above describes the adhesive composition, bonding film, laminate with adhesive layer, and laminate based on examples, but the specific aspects of the adhesive composition etc. according to the present invention are not limited to those of the examples, and the configuration can be changed as appropriate within the scope that does not impair the spirit of the present invention.

Claims

1. A base resin (A) containing at least one resin selected from the group consisting of a polyamide resin and a polyurethane resin, an epoxy compound (B) in an amount of 1 to 50 parts by mass based on 100 parts by mass of the base resin (A), a triazine compound (C) in an amount of 10 to 70 parts by mass based on 100 parts by mass of the base resin (A), and a metal phosphinate (D) in an amount of 0.5 to 50 parts by mass based on 100 parts by mass of the base resin (A), wherein the triazine compound (C) contains one or more structures represented by the following general formula (C1) and the following structural formula (C2) in its molecular structure, an adhesive composition. (However, in the general formula (C1), R 1 ~R 3 each independently represents an amino group, a hydroxy group, a thiol group, a methyl group or a phenyl group.) 2. The adhesive composition according to claim 1, wherein the triazine compound (C) contains a structure represented by the following structural formula (C3) in its molecular structure.

3. The adhesive composition according to claim 1, wherein the median diameter of the triazine compound (C) on a volume basis is 10 μm or less.

4. The adhesive composition according to claim 1, wherein the base resin (A) includes a polyester polyamide as a polyamide-based resin.

5. The adhesive composition according to claim 1, wherein the base resin (A) includes a polyester polyurethane as a polyurethane-based resin.

6. The adhesive composition according to claim 1, wherein the base resin (A) includes a polyurethane-based resin having a polyphenylene ether skeleton containing a plurality of phenylene groups and an ether bond connecting the phenylene groups to each other.

7. A bonding film having an adhesive layer and a release film provided on one or both surfaces of the adhesive layer and configured to be peelable from the adhesive layer, wherein the adhesive layer is composed of the adhesive composition according to any one of claims 1 to 6 or a semi-cured product obtained by partially curing the adhesive composition.

8. A laminate with an adhesive layer having an adhesive layer and a base material layer adhered to at least one surface of the adhesive layer, wherein the adhesive layer is composed of the adhesive composition according to any one of claims 1 to 6 or a semi-cured product obtained by partially curing the adhesive composition.

9. A laminate including a cured product layer made of a cured product of the adhesive composition according to any one of claims 1 to 6.

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