Adhesive composition, bonding film, laminate with adhesive layer, electromagnetic-wave-shielding material, and laminate

Abstract

This adhesive composition (100) comprises a polyamide-based resin (A), an epoxy compound (B), the amount of which is 1-50 parts by mass per 100 parts by mass of the polyamide-based resin (A), and a polyhydric phenol compound (C), the amount of which is 0.1-10 parts by mass per 100 parts by mass of the polyamide-based resin (A). The polyhydric phenol compound (C) has, in the molecular structure, a benzene ring having a plurality of phenolic hydroxyl groups. This bonding film (6) comprises an adhesive layer (10) and a release film (61) provided to one surface or both surfaces of the adhesive layer (10) and configured so as to be separable from the adhesive layer (10). The adhesive layer (10) is made of the adhesive composition (100) or of a semi-cured object obtained by partially curing the adhesive composition (100).

Description

Adhesive composition, bonding film, laminate with adhesive layer, electromagnetic wave shielding material and laminate

[0001] The present invention relates to an adhesive composition, a bonding film, a laminate with an adhesive layer, an electromagnetic wave shielding material, 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] Furthermore, in order to reduce electromagnetic noise entering the printed wiring board from the outside or generated by the printed wiring board, an electromagnetic wave shielding material is sometimes applied to the surface of the printed wiring board. This type of electromagnetic wave shielding material has one or more layers including an adhesive layer, and at least one of the layers constituting the electromagnetic wave shielding material is conductive.

[0007] As an adhesive used in the production of FPCs and related products, for example, Patent Document 1 describes an adhesive composition containing (A) a polycondensation polymer having a Tg of 150° C. or less and (B) a thermosetting resin. The polycondensation polymer (A) in Patent Document 1 is obtained by polycondensing an acid including a dimer acid, which is a dimer of an unsaturated fatty acid having 20 to 50 carbon atoms, with a diamine and / or a diisocyanate.

[0008] JP 2011-42730 A

[0009] Adhesives used in the manufacture of FPCs and related products are desired to have high adhesive strength and to maintain high adhesive strength even after heat is applied by soldering, etc. Furthermore, when the adhesive is conductive, it is desired to improve the conductivity of the adhesive layer and to maintain high conductivity even after heat is applied by soldering, etc.

[0010] The present invention has been made in view of the above background, and aims to provide an adhesive composition that has high adhesive strength and high solder heat resistance, and that, when electrical conductivity is imparted to the adhesive, can maintain high electrical conductivity even after heat is applied, as well as a bonding film, a laminate with an adhesive layer, an electromagnetic wave shielding material, and a laminate obtained using this adhesive composition.

[0011] A first aspect of the present invention resides in an adhesive composition according to the following items [1] to

[11] .

[0012] [1] An adhesive composition comprising: a polyamide resin (A); an epoxy compound (B) in an amount of 1 part by mass or more and 50 parts by mass or less per 100 parts by mass of the polyamide resin (A); and a polyhydric phenol compound (C) in an amount of 0.1 parts by mass or more and 10 parts by mass or less per 100 parts by mass of the polyamide resin (A), wherein the polyhydric phenol compound (C) has a benzene ring with a plurality of phenolic hydroxyl groups in its molecular structure.

[0013] [2] The adhesive composition according to [1], wherein, among the plurality of phenolic hydroxyl groups in the polyhydric phenol compound (C), a first phenolic hydroxyl group is located at the ortho position relative to a second phenolic hydroxyl group. [3] The adhesive composition according to [2], wherein the polyhydric phenol compound (C) has a partial structure represented by the following structural formula (C1) or the following structural formula (C2).

[0014]

[0015] However, the symbol "*" in the structural formula (C1) and the structural formula (C2) represents a bond to another atom.

[0016] [4] The adhesive composition according to any one of [1] to [3], wherein the polyhydric phenol compound (C) has a molecular weight of not more than 500. [5] The adhesive composition according to any one of [1] to [4], wherein the polyhydric phenol compound (C) contains an ester bond.

[0017] [6] The adhesive composition according to any one of [1] to [5], wherein the polyamide resin (A) is a polyester polyamide containing an amide bond and an ester bond. [7] The adhesive composition according to any one of [1] to [6], wherein the polyamide resin (A) has an acid value of 0.1 mgKOH / g or more and 5 mgKOH / g or less. [8] The adhesive composition according to any one of [1] to [7], wherein the polyamide resin (A) has a weight average molecular weight of 5,000 or more and 150,000 or less.

[0018] [9] The adhesive composition according to any one of [1] to [8], further comprising an inorganic filler (D).

[10] The adhesive composition according to [9], wherein the content of the inorganic filler (D) is 10 parts by mass or more and 350 parts by mass or less per 100 parts by mass of the total content of the polyamide resin (A), the epoxy compound (B), and the polyhydric phenol compound (C).

[11] The adhesive composition according to [9] or

[10] , wherein the inorganic filler (D) is electrically conductive.

[0019] A second aspect of the present invention is a bonding film according to the following item

[12] :

[12] 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

[11] or a semi-cured product obtained by partially curing the adhesive composition.

[0020] A third aspect of the present invention resides in a laminate with an adhesive layer according to the following item

[13] :

[13] 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

[11] or a semi-cured product obtained by partially curing the adhesive composition.

[0021] A fourth aspect of the present invention resides in the electromagnetic shielding materials according to the following items

[14] to

[15] .

[14] An electromagnetic shielding material having a conductive adhesive layer, wherein the conductive adhesive layer is composed of the adhesive composition according to item

[11] , a semi-cured product obtained by partially curing the adhesive composition, or a cured product of the adhesive composition.

[15] The electromagnetic shielding material according to item

[14] , which has a protective layer provided on the conductive adhesive layer.

[0022] A fifth aspect of the present invention is a laminate according to the following item

[16] :

[16] A laminate comprising a cured product layer made of a cured product of the adhesive composition according to any one of items [1] to

[11] .

[0023] The adhesive composition contains a polyamide resin (A), an epoxy compound (B), and a polyhydric phenol compound (C) in the above-mentioned specific ratio. By curing an adhesive composition having such a composition, an adhesive layer with high adhesive strength is formed, and adherends can be firmly bonded to each other. Furthermore, an adhesive layer made of a cured product of the adhesive composition can maintain high adhesive strength even after heat is applied by soldering or the like. Furthermore, by curing the adhesive composition to which conductivity has been imparted, a conductive adhesive layer can be formed that can maintain high conductivity even after heat is applied by soldering or the like.

[0024] Therefore, according to the above-mentioned aspect, it is possible to provide an adhesive composition that has high adhesive strength and high solder heat resistance, and, if the adhesive has conductivity, can maintain high conductivity even after heat is applied, as well as a bonding film, a laminate with an adhesive layer, an electromagnetic wave shielding material, and a laminate obtained using this adhesive composition.

[0025] Fig. 1 is a partial cross-sectional view showing a main part of test piece A in the example. Fig. 2 is a partial cross-sectional view showing a main part of test piece B in the example. Fig. 3 is a partial cross-sectional view showing a main part of a bonding film used to prepare test piece B. Fig. 4 is a partial cross-sectional view showing a main part of test piece C in the example.

[0026] (Adhesive composition) [Polyamide-based resin (A)] The adhesive composition contains a polyamide-based resin (A) having amide bonds that bond repeating units. The adhesive composition may contain one type of polyamide-based resin (A), or may contain two or more types of polyamide-based resins (A) having different structures.

[0027] In this specification, polyamide-based resin (A) refers to a resin containing a polyamide moiety in which multiple repeating units are bonded via amide bonds. That is, polyamide-based resin (A) may be, for example, a polyamide in which one or more types of repeating units are bonded via amide bonds. Furthermore, polyamide-based resin (A) may be, for example, a resin containing an amide bond and a bonding group other than an amide bond as the bonding group connecting the repeating units. Examples of such resins include polyester polyamides containing an amide bond and an ester bond as the bonding group. Polyamide-based resin (A) may have a linear molecular structure or a molecular structure containing a branched chain.

[0028] From the viewpoint of more reliably obtaining the effect of improving adhesive strength and the effect of maintaining high adhesive strength and high electrical conductivity even after application of heat, it is preferable that the polyamide-based resin (A) is a polyester polyamide containing an amide bond and an ester bond.

[0029] From the same viewpoint, the acid value of the polyamide resin (A) is preferably 0.1 mgKOH / g or more and 5 mgKOH / g or less. The acid value of the polyamide resin (A) is a value measured and calculated by potentiometric titration in accordance with JIS K 2501:2003.

[0030] From the viewpoint of adhesiveness, the amine value of the polyamide resin (A) 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 polyamide resin (A) is a value measured and calculated by potentiometric titration in accordance with JIS K 7237-1995.

[0031] The weight-average molecular weight of the polyamide resin (A) 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. In this case, the heat resistance of the cured product can be further improved. From the same viewpoint, the number-average molecular weight of the polyamide resin (A) is preferably 1,500 to 100,000, more preferably 10,000 to 25,000, and even more preferably 13,000 to 20,000. The number-average molecular weight and weight-average molecular weight of the polyamide resin (A) are polystyrene-equivalent values ​​obtained by gel permeation chromatography (hereinafter also referred to as "GPC") using polystyrene as a standard substance.

[0032] 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

[0033] From the viewpoints of adhesion and heat resistance, the content of the polyamide resin (A) in the adhesive composition is preferably 5% by mass or more and 90% by mass or less, more preferably 10% by mass or more and 80% by mass or less, even more preferably 20% by mass or more and 75% by mass or less, and particularly preferably 30% by mass or more and 70% by mass or less, relative to the total solid content of the adhesive composition.

[0034] The polyamide-based resin (A) may be a polyamide in which one or more types of repeating units are bonded via amide bonds. The adhesive composition may contain one type of polyamide, or two or more types of polyamide.

[0035] 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 amine 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.

[0036] 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.

[0037] 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.

[0038] 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.

[0039] 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.

[0040] 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, or may contain repeating units derived from the dimerized aliphatic diacids.

[0041] From the viewpoint of further improving the solder heat resistance and adhesiveness of the cured product, the polyamide preferably contains repeating units 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 repeating units 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 is preferably 30 to 48, more preferably 32 to 40.

[0042] 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.

[0043] From the viewpoint of further improving the solder heat resistance of the cured product, 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 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.

[0044] 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.

[0045] 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, for example, when a cured product is to be obtained by reacting the polyamide with a curing agent, the introduction of a branched chain into the polyamide increases the terminal group concentration (i.e., reaction sites) of the resin, thereby enabling the production of a cured product with a high crosslink density.

[0046] 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.

[0047] 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).

[0048] 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.

[0049] 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.

[0050] In producing polyamide, a catalyst used to promote esterification reaction, such as tetrabutoxy titanate, can be used as needed to promote the amidation reaction. In addition, in producing polyamide, a condensing agent can also be used as needed.

[0051] When producing a polyamide, a chain extender may be used as needed. Examples of the chain extender include diols used in the production of polyester polyamides described below, compounds having one carboxy group and two hydroxy groups such as dimethylolpropionic acid and dimethylolbutanoic acid, and polyamines.

[0052] 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.

[0053] The polyamide-based resin (A) may be a polyester polyamide containing an amide bond and an ester bond. The adhesive composition may contain one type of polyester polyamide, or two or more types of polyester polyamides.

[0054] The polyester polyamide may have, for example, 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. In this case, the polyester portion may have two or more ester bonds. Also, 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.

[0055] The polyester polyamide may have a plurality of the polyester moieties and amide bonds bonding the polyester moieties together. The polyester polyamide may have a plurality of the polyamide moieties and ester bonds bonding the polyamide moieties together.

[0056] The polyester polyamide is preferably a resin having a polyester moiety and two or more amide bonds, a resin having a polyamide moiety and two or more ester bonds, or a resin having a polyester moiety and a polyamide moiety. The weight-average molecular weight of the polyester moiety may be 1,000 or more. The weight-average molecular weight of the polyamide moiety may be 1,000 or more. The upper limit of the weight-average molecular weight of each of the polyester moiety and the polyamide moiety is not particularly limited, but may be, for example, 150,000 or less.

[0057] 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.

[0058] 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.

[0059] 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.

[0060] 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.

[0061] 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.

[0062] 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.

[0063] Examples of aromatic-containing 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.

[0064] 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.

[0065] 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.

[0066] 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.

[0067] The polyester moiety in the polyester polyamide 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 moiety. Furthermore, for example, when a cured product is to be obtained by reacting the polyester polyamide with a curing agent, the introduction of a branched chain into the polyester moiety increases the terminal group concentration (i.e., reaction sites) of the resin, resulting in a cured product with a high crosslink density.

[0068] 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.

[0069] Examples of polyols having three or more hydroxy groups include glycerin, trimethylolethane, trimethylolpropane, and pentaerythritol.

[0070] 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.

[0071] 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.

[0072] 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, or may contain repeating units derived from the dimerized aliphatic diacids.

[0073] 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.

[0074] 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.

[0075] From the viewpoint of further improving the solder heat resistance of the cured product, 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.

[0076] 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.

[0077] 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.

[0078] From the viewpoint of adhesiveness and solder 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.

[0079] Furthermore, from the viewpoint of adhesiveness and solder 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.

[0080] 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.

[0081] 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.

[0082] When producing polyester polyamide, a catalyst used for promoting esterification reaction and / or amidation reaction, such as tetrabutoxy titanate, can be used as needed to promote the esterification reaction or amidation reaction. Furthermore, when producing polyester polyamide, a condensing agent, a chain extender, etc. can also be used as needed. The chain extender used in the production of polyester polyamide and its preferred embodiments are the same as those used in the production of polyamide.

[0083] 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.

[0084] 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).

[0085] 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.

[0086] [Epoxy Compound (B)] The adhesive composition contains 1 part by mass or more and 50 parts by mass or less of the epoxy compound (B) per 100 parts by mass of the polyamide-based 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 setting the content of the 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 the polyamide-based 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 the epoxy compound (B) is less than 1 part by mass per 100 parts by mass of the polyamide-based resin (A), the adhesive properties of the adhesive composition and the heat resistance of the cured product may be reduced.

[0087] On the other hand, if the content of the epoxy compound (B) is excessively high, the epoxy compound (B) may easily react with other functional groups in the adhesive composition, which may result in a decrease in storage stability. Such problems 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 polyamide resin (A).

[0088] 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 polyamide-based resin (A).

[0089] 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.

[0090] 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.

[0091] 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.

[0092] 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.

[0093] 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).

[0094] 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 polyamide resin (A), thereby further improving the heat resistance of the cured product.

[0095] 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).

[0096] [Polyphenol Compound (C)] The adhesive composition contains 0.1 to 10 parts by mass of a polyphenol compound (C) per 100 parts by mass of the polyamide-based resin (A). The polyphenol compound (C) has a benzene ring with multiple phenolic hydroxyl groups in its molecular structure. By incorporating 0.1 parts by mass or more of the polyphenol compound (C) having the specific structure per 100 parts by mass of the polyamide-based resin (A) into the adhesive composition, adhesive strength can be improved. Furthermore, by incorporating the specific amount of the polyphenol compound (C) into the adhesive composition to which electrical conductivity has been imparted, a cured product can be formed that maintains high electrical conductivity even after heat is applied.

[0097] From the viewpoint of obtaining these effects more reliably, the content of the polyhydric phenol compound (C) is preferably 0.3 parts by mass or more, more preferably 0.5 parts by mass or more, even more preferably 0.7 parts by mass or more, and particularly preferably 1.0 part by mass or more, relative to 100 parts by mass of the polyamide-based resin (A). If the content of the polyhydric phenol compound (C) is less than 0.1 parts by mass or more than 10 parts by mass relative to 100 parts by mass of the polyamide-based resin (A), it may be difficult to obtain the above-mentioned effects.

[0098] On the other hand, by setting the content of the polyhydric phenol compound (C) to preferably 8 parts by mass or less, more preferably 6 parts by mass or less, even more preferably 4 parts by mass or less, and particularly preferably 3 parts by mass or less, per 100 parts by mass of the polyamide-based resin (A), the solder heat resistance of the cured product in a moisture-absorbed state can be further improved, and peeling between the cured product of the adhesive composition and the adherend can be suppressed.

[0099] When determining a preferred range for the content of the polyhydric phenol compound (C), the above-described upper and lower limits for the content of the polyhydric phenol compound (C) can be combined in any manner. The preferred range for the content of the polyhydric phenol compound (C) may be, for example, 0.3 parts by mass or more and 8 parts by mass or less, 0.5 parts by mass or more and 6 parts by mass or less, 0.7 parts by mass or more and 4 parts by mass or less, or 1.0 parts by mass or more and 3 parts by mass or less.

[0100] The adhesive composition may contain one type of polyhydric phenol compound (C), or may contain two or more types of polyhydric phenol compounds (C). Examples of the polyhydric phenol compound (C) include benzenediol and its derivatives, and benzenetriol and its derivatives.

[0101] Examples of benzenediols and derivatives thereof include catechol, catechol derivatives, resorcinol, resorcinol derivatives, hydroquinone, and hydroquinone derivatives, while examples of benzenetriols and derivatives thereof include hydroxyquinol, hydroxyquinol derivatives, phloroglucinol, phloroglucinol derivatives, pyrogallol, and pyrogallol derivatives.

[0102] Among the plurality of phenolic hydroxyl groups in the polyhydric phenol compound (C), it is preferable that the first phenolic hydroxyl group is located at the ortho position relative to the second phenolic hydroxyl group. In this case, the above-mentioned effects can be more reliably obtained. From the same viewpoint, it is more preferable that the polyhydric phenol compound (C) has a partial structure represented by the following structural formula (C1) or the following structural formula (C2).

[0103]

[0104] However, the symbol "*" in the structural formula (C1) and the structural formula (C2) represents a bond to another atom.

[0105] Examples of compounds having a partial structure represented by structural formula (C1) include 4-tert-butylpyrocatechol, 3,4-dihydroxyhydrocinnamic acid, "CM03" manufactured by Osaka Organic Chemical Industry Ltd., and dopamine acrylamide. Examples of compounds having a partial structure represented by structural formula (C2) include gallic acid, gallic acid alkyl esters, and "GA-MA" manufactured by NOF Corporation.

[0106] Furthermore, in the polyhydric phenol compound (C), various substituents may be bonded to the benzene ring having a phenolic hydroxyl group. From the viewpoint of more reliably achieving the above-mentioned effects, it is preferable that the substituent bonded to the benzene ring having a phenolic hydroxyl group is any one type of substituent selected from the group consisting of alkyl groups having from 1 to 20 carbon atoms and substituents represented by the following structural formulas (C3) to (C6). From the same viewpoint, it is preferable that the polyhydric phenol compound (C) does not contain any aromatic ring other than the benzene ring having a phenolic hydroxyl group in its molecular structure.

[0107]

[0108] However, the symbol "*" in the general formulae (C3) to (C6) represents a bond to a benzene ring, n in the general formulae (C3) to (C5) represents an integer of 0 or more and 20 or less, and R in the general formula (C4) represents an alkyl group having 1 or more and 20 or less carbon atoms.

[0109] The molecular weight of the polyhydric phenol compound (C) is preferably 500 or less. In this case, the adhesive strength can be more easily improved, and a cured product that can maintain high conductivity even when heated can be more easily formed. On the other hand, the molecular weight of the polyhydric phenol compound (C) is preferably 130 or more, more preferably 140 or more, even more preferably 150 or more, and particularly preferably 160 or more. In this case, the polyhydric phenol compound (C) is less likely to volatilize, and therefore a cured product that can maintain high conductivity even after heated can be more easily formed.

[0110] When constituting a preferred range of the molecular weight of the polyhydric phenol compound (C), the above-mentioned upper and lower limits of the molecular weight of the polyhydric phenol compound (C) can be combined arbitrarily. The preferred range of the molecular weight of the polyhydric phenol compound (C) may be, for example, 130 to 500, 140 to 500, 150 to 500, or 160 to 500.

[0111] The polyhydric phenol compound (C) may contain an ester bond in its molecular structure, which makes it easier to improve adhesive strength and to form a cured product that can maintain high electrical conductivity even when heated.

[0112] [Inorganic Filler (D)] The adhesive composition may further contain an inorganic filler (D). 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 polyamide resin (A), the epoxy compound (B), and the polyhydric phenol compound (C).

[0113] Examples of the inorganic filler (D) 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.

[0114] From the viewpoint of more easily imparting electrical conductivity to the cured product of the adhesive composition, it is preferred that the inorganic filler (D) be electrically conductive.

[0115] [Imidazole Silane] The adhesive composition may contain an imidazole silane having one or more imidazole ring structures and one or more silane structures. By incorporating an imidazole silane 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 exhibit high affinity with metal surfaces. It is also believed that the imidazole silane 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.

[0116] The silane structure in the imidazole silane is preferably a silyl group, and more preferably an alkoxysilyl group, which can further improve the solder heat resistance of the adhesive composition.

[0117] The imidazole ring structure in the imidazole silane may have an imidazole ring having a substituent such as a saturated hydrocarbon group or an unsaturated hydrocarbon group, etc. More specifically, the imidazole ring structure may include an imidazole ring, a 2-alkylimidazole ring, a 2,4-dialkylimidazole ring, a 4-vinylimidazole ring, etc.

[0118] From the viewpoint of further enhancing the adhesiveness of the adhesive composition, the imidazole silane is more preferably a compound represented by the following general formula (I1) or an acid adduct thereof.

[0119]

[0120] R in the general formula (I1) 1 and R 2 R each independently represents a hydrogen atom, a saturated hydrocarbon group, an unsaturated hydrocarbon group, or an aryl group. 1 and R 2The saturated hydrocarbon group, unsaturated hydrocarbon group and aryl group in the general formula (I1) may have a substituent. 3 and R 4 R each independently represents a hydrogen atom or an alkyl group. 3 At least one of R is an alkyl group. In the general formula (I1), n ​​is an integer of 1 or more and 3 or less. 1 ~R 4 The alkyl group in R preferably has 1 or more and 3 or less carbon atoms. 3 and R 4 The alkyl group in the formula (I) may have a substituent.

[0121] R in the general formula (I1) 5 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 (I2) to (I5): 5 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.

[0122]

[0123] R in the structural formula (I2) 6 represents a hydrogen atom or a hydroxy group. 7 represents a hydrogen atom, an alkyl group, or an aryl group. 8 and R 9 R each independently represents a hydrogen atom, an alkyl group, or an aryl group. 7 , R 8 and R 9 The alkyl group and aryl group in the formula (I) may have a substituent.

[0124] Imidazole silane can be suitably synthesized, for example, by reacting an imidazole compound with a 3-glycidoxyalkylsilane compound or the like. Furthermore, the imidazole silane 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. Furthermore, the imidazole silane may have both a silanol group and a polyorganosiloxane structure.

[0125] Examples of the acid to be added to the compound represented by general formula (I1) include acetic acid, lactic acid, salicylic acid, benzoic acid, adipic acid, phthalic acid, citric acid, tartaric acid, maleic acid, trimellitic acid, phosphoric acid, isocyanuric acid, etc. These acids may be used alone or in combination of two or more.

[0126] From the viewpoint of adhesiveness, the imidazole silane is more preferably a compound represented by the following general formula (I6) or general formula (I7), or an acid adduct thereof.

[0127]

[0128] R in the general formula (I6) and general formula (I7) 1 and R 2 R each independently represents a hydrogen atom, a saturated hydrocarbon group, an unsaturated hydrocarbon group, or an aryl group. 1 and R 2 The saturated hydrocarbon group, unsaturated hydrocarbon group and aryl group in the general formula (I6) and the general formula (I7) may have a substituent. 3 and R 4 R each independently represents a hydrogen atom or an alkyl group. 3 At least one of R is an alkyl group. In the general formula (I6) and the general formula (I7), n is an integer of 1 or more and 3 or less. 1 ~R 4 The alkyl group in R preferably has 1 or more and 3 or less carbon atoms. 3 and R 4 The alkyl group in the formula (I) may have a substituent.

[0129] R in the general formula (I6) and general formula (I7) 5’ represents an alkylene group. 5’ The number of carbon atoms in the alkylene group in the general formula (I6) and the general formula (I7) is preferably 1 or more and 10 or less, and more preferably 3 or more and 7 or less. 10 represents a hydrogen atom or a hydroxy group.

[0130] More specifically, examples of the imidazole silane 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.

[0131] 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, the imidazole silane is more preferably an acid adduct of the compound represented by general formula (I6).

[0132] The compound represented by the general formula (I6) 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 (I6) is particularly preferably a reaction product of imidazole and 3-glycidoxypropyltrimethoxysilane.

[0133] The compound represented by the general formula (I7) can be easily obtained by reacting an imidazole compound with 3-methacryloyloxypropyltrimethoxysilane or the like.

[0134] The adhesive composition may contain one type of imidazole silane or two or more types of imidazole silane. From the viewpoint of adhesiveness, the content of the imidazole silane 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 polyamide resin (A) and the epoxy compound (B).

[0135] [Organic Filler] The adhesive composition may further contain an organic filler. By incorporating an organic filler into the adhesive composition, the solder heat resistance and moist heat resistance can be further improved. Furthermore, since the organic filler has excellent compatibility with the polyamide-based resin (A) and the like, by incorporating an organic filler into the liquid adhesive composition, the stability of the liquid can be improved.

[0136] 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.

[0137] 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.

[0138] 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 polyamide-based resin (A), the epoxy compound (B), and the polyhydric phenol compound (C).

[0139] [Additives] The adhesive composition may contain additives other than the above-mentioned components, as long as the above-mentioned effects are not impaired. Examples of additives include thermoplastic resins other than the polyamide-based resin (A), tackifiers, flame retardants, curing agents, curing accelerators, coupling agents, heat aging inhibitors, leveling agents, antifoaming agents, and solvents.

[0140] Examples of thermoplastic resins that can be contained in the adhesive composition include phenoxy 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.

[0141] 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.

[0142] As the flame retardant, an organic flame retardant or an inorganic flame retardant can be used. Examples of organic flame retardants include phosphorus-based flame retardants such as melamine phosphate, melamine polyphosphate, guanidine phosphate, guanidine polyphosphate, ammonium phosphate, ammonium polyphosphate, ammonium amido phosphate, ammonium amido polyphosphate, carbamate phosphate, carbamate polyphosphate, aluminum trisdiethylphosphinate, aluminum trismethylethylphosphinate, aluminum trisdiphenylphosphinate, zinc bisdiethylphosphinate, zinc bismethylethylphosphinate, zinc bisdiphenylphosphinate, titanyl bisdiethylphosphinate, titanium tetrakisdiethylphosphinate, titanyl bismethylethylphosphinate, titanium tetrakismethylethylphosphinate, titanyl bisdiphenylphosphinate, and titanium tetrakisdiphenylphosphinate; nitrogen-based flame retardants such as triazine-based compounds such as melamine, melam, and melamine cyanurate, cyanuric acid compounds, isocyanuric acid compounds, triazole-based compounds, tetrazole compounds, diazo compounds, and urea; and silicon-based flame retardants such as silicone compounds and silane compounds.

[0143] 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.

[0144] 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 diamine-based curing agents, chain aliphatic polyamine-based curing agents, alicyclic diamine-based curing agents, and aromatic diamine-based curing agents), polyamidoamine-based curing agents, chain aliphatic polycarboxylic acid-based curing agents, alicyclic polycarboxylic acid-based curing agents, and aromatic polycarboxylic acid-based curing agents.

[0145] Examples of the chain aliphatic diamine curing agent include ethylenediamine, 1,3-diaminopropane, 1,4-diaminobutane, hexamethylenediamine, polymethylenediamine, polyetherdiamine, 2,5-dimethylhexamethylenediamine, and trimethylhexamethylenediamine.

[0146] Examples of the chain aliphatic polyamine curing agent include diethylenetriamine, iminobis(hexamethylene)triamine, trihexatetramine, tetraethylenepentamine, aminoethylethanolamine, tri(methylamino)hexane, dimethylaminopropylamine, diethylaminopropylamine, and methyliminobispropylamine.

[0147] 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.

[0148] Examples of aromatic diamine curing agents include metaphenylenediamine, diaminodiphenylmethane, diaminodiphenylsulfone, diaminodiethyldiphenylmethane, and metaxylylenediamine.

[0149] Examples of the chain aliphatic polycarboxylic acid curing agent include succinic acid, adipic acid, dodecenyl succinic anhydride, polyadipic anhydride, polyazelaic anhydride, and polysebacic anhydride.

[0150] Examples of alicyclic polycarboxylic acid curing agents include methyltetrahydrophthalic acid, methylhexahydrophthalic acid, methylhimic acid, hexahydrophthalic acid, tetrahydrophthalic acid, trialkyltetrahydrophthalic acid, methylcyclodicarboxylic acid, and acid anhydrides thereof.

[0151] Examples of aromatic polycarboxylic acid curing agents include phthalic acid, trimellitic acid, pyromellitic acid, benzophenone tetracarboxylic acid, ethylene glycol bistrimellitic acid, glycerol tristrimellitic acid, and acid anhydrides thereof.

[0152] 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.

[0153] 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).

[0154] 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.

[0155] 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.

[0156] 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.

[0157] 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.

[0158] 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).

[0159] 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.

[0160] 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.

[0161] 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.

[0162] 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.

[0163] 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.

[0164] 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.

[0165] The polyamide resin (A) has the property of being easily soluble in protic solvents. Therefore, from the viewpoint of more easily dissolving the polyamide resin (A) in a solvent, the adhesive composition preferably 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.

[0166] [Method of Use of Adhesive Composition] The method of use of the adhesive composition is not particularly limited, and the adhesive composition can be used in various embodiments. For example, the adhesive composition may 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.

[0167] (Bonding Film) A bonding film can be obtained by providing 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 thereof.

[0168] 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 the adhesive composition or its semi-cured product, 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.

[0169] Furthermore, the cured product of the adhesive composition exhibits excellent heat resistance even when hygroscopic, and is able to 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, the adherend is unlikely to peel from the cured product when heated. Bonding films with such properties are suitable for the production of FPCs and FPC-related products.

[0170] 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.

[0171] 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.

[0172] 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. As a method for applying the adhesive composition to a release film, an appropriate method 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 can be adopted.

[0173] 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.

[0174] (Laminate with adhesive layer) A laminate with an adhesive layer can be obtained by providing the adhesive composition or a semi-cured product thereof 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 thereof.

[0175] 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.

[0176] Furthermore, as mentioned 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, the adherend is unlikely to peel from the cured product 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.

[0177] 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.

[0178] 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.

[0179] 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.

[0180] 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.

[0181] 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.

[0182] 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.

[0183] (Electromagnetic wave shielding material) The conductive adhesive composition can also be used to produce an electromagnetic wave shielding material. The electromagnetic wave shielding material has, for example, a conductive adhesive layer, and the conductive adhesive layer is composed of the conductive adhesive composition or a semi-cured product thereof.

[0184] The electromagnetic wave shielding material has a conductive adhesive layer composed of an uncured adhesive composition or a semi-cured product of the adhesive composition. Therefore, the conductive adhesive layer can be applied to a desired portion of the surface of an adherend, including a ground wiring, and then further cured by heat pressing or the like to form a conductive cured material layer on the adherend. The conductive cured material layer thus formed is electrically connected to the ground wiring, thereby reducing electromagnetic noise entering the printed wiring board from the outside and electromagnetic noise generated by the printed wiring board. Furthermore, because the conductive cured material layer is composed of a cured product of the adhesive composition, it can easily maintain high conductivity even when heat is applied, as described above. Therefore, the electromagnetic wave shielding material can easily maintain its electromagnetic noise reduction effect even when heat is applied.

[0185] The electromagnetic wave shielding material may be composed of only a conductive adhesive layer, or may be composed of two or more layers including a conductive adhesive layer. For example, the electromagnetic wave shielding material may have a conductive adhesive layer and a release film provided on one or both sides of the conductive adhesive layer. Alternatively, the electromagnetic wave shielding material may have, for example, a conductive adhesive layer and a conductor layer provided on one side of the conductive adhesive layer. In this case, the conductive cured product layer electrically connects the conductor layer to the ground wiring of the adherend, thereby further enhancing the effect of reducing electromagnetic noise.

[0186] The electromagnetic wave shielding material may also have a conductive adhesive layer and a protective layer provided on one side of the conductive adhesive layer. By providing the protective layer on the conductive adhesive layer in this way, the conductive cured material layer is less susceptible to damage due to wear and tear. As a result, the electromagnetic noise reduction effect can be maintained for a longer period of time.

[0187] The conductive adhesive layer is preferably composed of, for example, an adhesive composition containing a conductive inorganic filler (D), or a semi-cured or cured product thereof. The thickness of the conductive adhesive layer is not particularly limited, but is preferably 3 μm or more and 30 μm or less from the viewpoints of conductivity and electrical connection with the ground wiring.

[0188] The protective layer may take various forms as long as it has electrical insulation properties. For example, the protective layer may be composed of an electrically insulating adhesive or resin film. Alternatively, the protective layer may be composed of the adhesive composition or a semi-cured product thereof that does not have electrical conductivity. The protective layer may contain, as necessary, a curing accelerator, a tackifier, an antioxidant, a pigment, a dye, a plasticizer, an ultraviolet absorber, an antifoaming agent, a leveling agent, a filler, a flame retardant, a viscosity modifier, an antiblocking agent, and the like. Furthermore, two or more protective layers composed of different materials may be provided on the conductive adhesive layer.

[0189] The method for producing the electromagnetic wave shielding material is the same as the method for producing the bonding film described above. For example, when a protective layer is formed using the adhesive composition having electrical insulation properties and a conductive adhesive layer is formed using the adhesive composition having electrical conductivity, the following method can be adopted. First, an adhesive composition for forming a protective layer is applied to a release film. The adhesive composition is then dried and cured as necessary to form a protective layer on the release film. Next, an adhesive composition for forming a conductive adhesive layer is applied to the protective layer. The adhesive composition on the protective layer is then dried, thereby forming a conductive adhesive layer on the protective layer.

[0190] (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.

[0191] 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.

[0192] 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.

[0193] 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.

[0194] 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.

[0195] 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.

[0196] Examples of the adhesive composition are described below. In these examples, the adhesive composition was prepared using the following raw materials.

[0197] (Polyamide Resin (A)) In this example, polyester polyamide a1, polyester polyamide a2, or polyamide a3 was used as the polyamide resin (A). The methods for producing these polyamide resins are as follows.

[0198] [Polyester Polyamide a1] 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 raised to 120°C to distill off water. The flask was then further heated, and the temperature of the contents was raised to 240°C at a rate of 20°C / hour. After maintaining this temperature for 1 hour, 200 parts by weight of azelaic acid, 120 parts by weight of neopentyl glycol, 5 parts by weight of trimethylolpropane, 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 drop to 150°C.

[0199] 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 11.1 mgKOH / g. Thus, polyester polyamide a1 in pellet form was obtained. The acid value of polyester polyamide a1 was 1.1 mgKOH / g. The acid value of polyester polyamide a1 was measured and calculated by potentiometric titration in accordance with JIS K 2501:2003.

[0200] [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.

[0201] 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, pelletized polyester polyamide a2 was obtained. The acid value of polyester polyamide a2 was 1.3 mgKOH / g. The acid value of polyester polyamide a2 was measured and calculated by potentiometric titration in accordance with JIS K 2501:2003.

[0202] [Polyamide a3] A flask equipped with a stirrer, a reflux dehydration apparatus, and a distillation tube was charged with 65 parts by mass of azelaic acid, 190 parts by mass of dodecanedioic acid, 100 parts by mass of piperazine, and 120 parts by mass of distilled water. 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. This temperature was maintained for 3 hours to continue the reaction. Polyamide a3 was obtained in this manner.

[0203] (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)

[0204] (Polyphenol Compounds (C)) The polyphenol compounds (C) used in this example are as follows: Polyphenol compound c1: 4-tert-butylpyrocatechol Polyphenol compound c2: 3,4-dihydroxyhydrocinnamic acid Polyphenol compound c3: a compound represented by the following structural formula (C7) ("CM03" manufactured by Osaka Organic Chemical Industry Ltd.) Polyphenol compound c4: dopamine acrylamide Polyphenol compound c5: a compound represented by the following structural formula (C8) ("GA-MA" manufactured by NOF Corporation) Polyphenol compound c6: gallic acid Polyphenol compound c7: ethyl gallate Polyphenol compound c8: octyl gallate Polyphenol compound c9: hexadecyl gallate

[0205]

[0206] (Inorganic Filler (D)) The inorganic filler d1 used in this example has electrical conductivity. More specifically, the inorganic filler d1 is copper powder ("FCC-115A" manufactured by Fukuda Metal Foil & Powder Co., Ltd.).

[0207] (Other Components) The other components used in this example are as follows.

[0208] Flame retardant: phosphinic acid metal salt-based flame retardant ("Exolit (registered trademark) OP935" manufactured by Clariant) Flame retardant synergist: melamine cyanurate Curing accelerator: imidazole-based curing accelerator ("Curesol (registered trademark) C11-Z" manufactured by Shikoku Chemicals Corporation) Solvent: mixed solvent obtained by mixing 20 parts by mass of methyl ethyl ketone and 20 parts by mass of 2-propanol with 100 parts by mass of toluene Polyolefin resin: maleic anhydride-modified propylene-butene copolymer resin ("Toyotack (registered trademark) PMA-L" manufactured by Toyobo Co., Ltd., weight average molecular weight 75,000)

[0209] [Polyester Polyurethane] 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 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-bis(hydroxymethyl)propionic acid was added to the flask and dissolved in the contents.

[0210] 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 / 2-propanol to adjust the solids concentration to 30% by mass. This yielded a solution containing polyester polyurethane. The polyester polyurethane had a number average molecular weight of 35,000 and an acid value of 2 mgKOH / g.

[0211] [Polyphenylene ether polyurethane] 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.

[0212] 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. The polyurethane 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.

[0213] (Examples 1 to 19 and Comparative Examples 1 to 9) The above raw materials were added to a flask equipped with a stirrer in the proportions shown in Tables 1 to 3, and the flask was then heated to raise the temperature of the contents to 60°C. The contents were then stirred for 6 hours while maintaining the temperature, thereby dissolving the polyamide-based resin (A), polyolefin-based resin, polyester polyurethane, polyphenylene ether polyurethane, epoxy compound (B), polyhydric phenol compound (C), and curing accelerator in the solvent, and dispersing the inorganic filler (D), flame retardant, and flame retardant aid. In this manner, liquid adhesive compositions were prepared. The amounts of polyamide-based resin (A), polyester polyurethane, and polyurethane in Tables 1 and 2 refer to the amounts of solids (i.e., the amounts of polyamide-based resin (A), polyolefin-based resin, polyester polyurethane, or polyphenylene ether polyurethane excluding the solvent).

[0214] Next, test pieces A to C were prepared by the following method using the adhesive compositions of the examples and comparative examples.

[0215] [Test Piece A] As shown in Fig. 1, test piece A has a polyimide film 2, a conductive cured material layer 1 provided on the polyimide film 2, and a copper foil 3 provided on the cured material layer 1. The polyimide film 2 and the copper foil 3 are bonded together via the cured material layer 1. The thickness of the polyimide film 2 is 25 µm, and the thickness of the cured material layer 1 is 15 µm. The copper foil 3 used was a rolled copper foil with a thickness of 35 µm.

[0216] The test piece A was prepared as follows: First, the adhesive composition was applied to a polyimide film 2 using a roll coater. Then, the adhesive composition on the polyimide film 2 was dried for 2 minutes in an oven set at a temperature of 120°C, thereby forming an adhesive layer on the polyimide film 2.

[0217] Next, the adhesive layer and copper foil 3 were bonded together so that the adhesive layer and the glossy surface of the copper foil 3 were in contact. This laminate was subjected to a thermal lamination process, which cured the adhesive layer to form a cured material layer 1 and bonded the cured material layer 1 to the copper foil 3. The heating temperature in the thermal lamination process was 150°C, the pressure was 0.3 MPa, and the lamination speed was 1 m / min. The laminate was then heated in an oven set at 160°C for 2 hours to perform after-cure, thereby obtaining test piece A.

[0218] 2, test piece B has a metal plate 4, a conductive cured material layer 1 provided on the metal plate 4, and a flexible printed wiring board 5 provided on the cured material layer 1, with the metal plate 4 and the flexible printed wiring board 5 being bonded together via the cured material layer 1. The metal plate 4 of test piece B is a 300 μm thick plate made of SUS304, and a nickel plating film (not shown) is formed on the surface of the plate.

[0219] The flexible printed wiring board 5 of test piece B includes a polyimide film 51, a circuit pattern 52 provided on a first surface 511 of the surfaces of the polyimide film 51, and a coverlay 53 covering the first surface 511 of the polyimide film and the circuit pattern 52. The polyimide film 51 has a thickness of 25 μm. The circuit pattern 52 is made of copper. The coverlay 53 has a thickness of 37.5 μm. The coverlay 53 also has a through hole 531 with a diameter of 1 mm at a position overlapping the circuit pattern 52.

[0220] A portion of the circuit pattern 52 is exposed inside the through-hole 531. The through-hole 531 is filled with the cured material layer 1, and the cured material layer 1 inside the through-hole 531 is in contact with the circuit pattern 52. In this way, the conductive cured material layer 1 is in contact with the circuit pattern 52 inside the through-hole 531, thereby electrically connecting the metal plate 4 and the flexible printed wiring board 5.

[0221] The method for producing test piece B is as follows. First, a bonding film 6 was prepared, which included a release film 61 and an adhesive layer 10 provided on the release film 61, as shown in FIG. 3. The release film 61 was made of polyethylene terephthalate. The release film 61 had a thickness of 35 μm. The adhesive layer 10 had a thickness of 25 μm. The adhesive layer 10 was made of an adhesive composition 100 or a semi-cured product thereof. The bonding film 6 was obtained by applying the adhesive composition 100 onto the release film 61 with a roll coater and then drying it at a temperature of 100° C. for 3 minutes.

[0222] Next, the bonding film 6 was attached to the metal plate 4 so that the adhesive layer 10 of the bonding film 6 was in contact with the nickel plating film of the metal plate 4. This laminate was subjected to a thermal lamination process to bond the metal plate 4 and the bonding film 6. The heating temperature in the thermal lamination process was 150°C, the pressure was 0.3 MPa, and the lamination speed was 1 m / min.

[0223] Next, the release film 61 was peeled off from the laminate to expose the adhesive layer 10. Thereafter, the laminate and flexible printed wiring board 5 were bonded together so that the adhesive layer 10 of the laminate came into contact with the coverlay 53 of the flexible printed wiring board 5. This laminate was subjected to a heat press treatment under conditions of a heating temperature of 150°C, a pressure of 0.3 MPa, and a heating time of 5 minutes, thereby curing the adhesive layer 10 to form a cured material layer 1 and bonding the flexible printed wiring board 5 and the metal plate 4 via the cured material layer 1. Thereafter, the laminate was heated for 2 hours in an oven set at a temperature of 160°C to perform after-curing, and a test piece B was obtained.

[0224] 4, the test piece C has an electrically conductive cured material layer 1 and polyimide films 7 (7a, 7b) 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 7 is 25 μm.

[0225] The test piece C was prepared as follows: First, the adhesive composition was applied with a roll coater to the surface of the first polyimide film 7a of the two polyimide films 7. The adhesive composition on the polyimide film 7a was then dried for 3 minutes in an oven set at 100°C, thereby preparing a coverlay film having the polyimide film 7a and an adhesive layer laminated on the polyimide film 7a.

[0226] Next, a second polyimide film 7b 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 7b 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 to the polyimide film 7b. The laminate thus obtained was cut to a predetermined size to obtain a test piece C.

[0227] Using the test pieces A to 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.

[0228] (Peel Adhesion Strength) Test piece A shown in Figure 1 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." More specifically, using bone-dry test piece A prepared by the above-mentioned method, the 180° peel adhesion strength (unit: N / cm) was measured when peeling the copper foil 3 from the polyimide film 1. The temperature during measurement was 23°C, and the pulling speed was 50 mm / min.

[0229] (Soldering Heat Resistance) Test piece A shown in Fig. 1 was used to evaluate the soldering heat resistance. The soldering heat resistance test was carried out in accordance with JIS C 6481-1996. In this example, the soldering heat resistance test was carried out using test piece A in an absolute dry state, after 24 hours of humidification, and after 72 hours of humidification, and the soldering heat resistance was evaluated based on the appearance of test piece A after the test.

[0230] Specifically, in the evaluation of bone-dry test piece A, test piece A obtained by the above-mentioned method was pretreated at 105±2°C, and immediately thereafter floated in a solder bath at 260°C for 60 seconds to conduct a soldering heat resistance test. In the evaluation of test piece A after 24 hours of humidification, test piece A was pretreated at 105±2°C, and then stored in an environment at a temperature of 30°C and a relative humidity of 60%RH for 24 hours to allow test piece A to absorb moisture. Thereafter, test piece A was floated in a solder bath at 260°C for 60 seconds to conduct a soldering heat resistance test. In the evaluation of test piece A after 72 hours of humidification, test piece A was pretreated at 105±2°C, and then stored in an environment at a temperature of 30°C and a relative humidity of 60%RH for 72 hours to allow test piece A to absorb moisture. Thereafter, test piece A was floated in a solder bath at 260°C for 60 seconds to conduct a soldering heat resistance test.

[0231] The appearance of test piece A after the soldering heat resistance test was thus performed was visually observed. The symbols listed in the "Soldering Heat Resistance" column in Tables 1 to 3 have the following meanings. A: No change in the appearance of test piece A was observed after the soldering heat resistance test. B: Blisters occurred on test piece A after the soldering heat resistance test, and the blister area ratio was more than 0% and 20% or less. C: Blisters occurred on test piece A after the soldering heat resistance test, and the blister area ratio was more than 20% and 50% or less. D: Blisters occurred on test piece A after the soldering heat resistance test, and the blister area ratio exceeded 50%.

[0232] (Electrical Conductivity) Test piece B shown in FIG. 2 was used to evaluate electrical conductivity. The electrical conductivity was evaluated based on the electrical resistance between the metal plate 4 and the circuit pattern 52 in the bone-dry state of test piece B. In the "Electrical Conductivity" column of Tables 1 to 3, the symbol "A" was entered when the electrical resistance between the metal plate 4 and the circuit pattern 52 was less than 0.1 Ω, the symbol "B" was entered when it was 0.1 Ω or more and less than 0.3 Ω, the symbol "C" was entered when it was 0.3 Ω or more and less than 1.0 Ω, and the symbol "D" was entered when it exceeded 1.0 Ω.

[0233] (Flame Retardancy) Using test piece C shown in Figure 4, flame retardancy was evaluated by a method conforming to UL 94. In the "Flame Retardancy" column of Tables 1 to 3, "Good" is entered when the flame retardancy based on UL 94 was judged to be VTM-0, and "Poor" is entered when it was judged to be VTM-1 or less.

[0234] (Storage Stability) Adhesive compositions were used to evaluate storage stability. In evaluating storage stability, first, the initial viscosity of the adhesive composition was measured. Then, the adhesive composition was sealed in a glass bottle and stored in an environment of 5°C. After two months had passed since the start of storage, the viscosity of the adhesive composition removed from the glass bottle was measured. Then, storage stability was evaluated based on the ratio of the viscosity after storage to the initial viscosity. In the "Storage Stability" column of Tables 1 to 3, the symbol "Good" was entered when the viscosity after storage was two times or less the initial viscosity, and the symbol "Poor" was entered when it was more than two times the initial viscosity.

[0235]

[0236]

[0237]

[0238] As shown in Tables 1 to 3, the adhesive compositions of Examples 1 to 19 contain a polyamide resin (A), an epoxy compound (B), and a polyhydric phenol compound (C). The contents of the epoxy compound (B) and the polyhydric phenol compound (C) are each within the specified ranges. Therefore, the adhesive compositions of these Examples exhibited high peel strength. Furthermore, by curing these adhesive compositions, it was possible to form cured products that maintained high adhesion and high conductivity even when heat was applied.

[0239] In contrast, as shown in Table 2, the adhesive compositions of Comparative Examples 1 to 3 did not contain polyamide resin (A). Therefore, the peel bond strengths of the adhesive compositions of Comparative Examples 1 to 3 were lower than the peel bond strengths of the adhesive compositions of Examples. Furthermore, when heat was applied to the cured products of the adhesive compositions of Comparative Examples 1 to 3, the electrical conductivity of the cured products decreased.

[0240] The adhesive composition of Comparative Example 4 did not contain the polyhydric phenol compound (C), and therefore had a lower peel bond strength than the adhesive compositions of Examples 1 to 16, which had similar compositions except for containing the polyhydric phenol compound (C). Furthermore, when heat was applied to the cured product of the adhesive composition of Comparative Example 4, the electrical conductivity of the cured product decreased.

[0241] The adhesive composition of Comparative Example 5 did not contain the polyhydric phenol compound (C), and therefore had a lower peel bond strength than the adhesive composition of Example 17, which had a similar composition except for containing the polyhydric phenol compound (C). Furthermore, when heat was applied to the cured product of the adhesive composition of Comparative Example 5, the electrical conductivity of the cured product decreased.

[0242] The adhesive composition of Comparative Example 6 did not contain the polyhydric phenol compound (C), and therefore had a lower peel bond strength than the adhesive composition of Example 18, which had a similar composition except for containing the polyhydric phenol compound (C). Furthermore, when heat was applied to the cured product of the adhesive composition of Comparative Example 6, the electrical conductivity of the cured product decreased.

[0243] The content of the polyhydric phenol compound (C) in the adhesive compositions of Comparative Examples 7 and 8 was greater than the specified range. As a result, the peel strength of the adhesive compositions of Comparative Examples 7 and 8 was lower than the peel strength of the adhesive compositions of Examples. Furthermore, when heat was applied to the cured products of the adhesive compositions of Comparative Examples 7 and 8, the electrical conductivity of the cured products decreased.

[0244] The adhesive composition of Comparative Example 9 shown in Table 3 did not contain the polyhydric phenol compound (C), and therefore had a lower peel bond strength than the adhesive composition of Example 19, which had a similar composition except for containing the polyhydric phenol compound (C). Furthermore, when heat was applied to the cured product of the adhesive composition of Comparative Example 9, the electrical conductivity of the cured product decreased.

[0245] The above has explained aspects of the adhesive composition, bonding film, laminate with an adhesive layer, electromagnetic wave shielding material, and laminate based on examples, but the specific aspects of the adhesive composition etc. according to the present invention are not limited to those in 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. An adhesive composition comprising: a polyamide resin (A); an epoxy compound (B) in an amount of 1 part by mass or more and 50 parts by mass or less per 100 parts by mass of the polyamide resin (A); and a polyhydric phenol compound (C) in an amount of 0.1 parts by mass or more and 10 parts by mass or less per 100 parts by mass of the polyamide resin (A), wherein the polyhydric phenol compound (C) has a benzene ring with multiple phenolic hydroxyl groups in its molecular structure.

2. The adhesive composition according to claim 1, wherein, of the plurality of phenolic hydroxyl groups in the polyhydric phenol compound (C), a first phenolic hydroxyl group is located at the ortho position relative to a second phenolic hydroxyl group.

3. The adhesive composition according to claim 2, wherein the polyhydric phenol compound (C) has a partial structure represented by the following structural formula (C1) or the following structural formula (C2). (However, the symbol "*" in the structural formula (C1) and the structural formula (C2) represents a bond to another atom.) 4. The adhesive composition according to claim 1, wherein the polyhydric phenol compound (C) has a molecular weight of 500 or less.

5. The adhesive composition according to claim 1, wherein the polyhydric phenol compound (C) contains an ester bond.

6. The adhesive composition according to claim 1, wherein the polyamide resin (A) is a polyester polyamide containing an amide bond and an ester bond.

7. The adhesive composition according to claim 1, wherein the acid value of the polyamide resin (A) is 0.1 mgKOH / g or more and 5 mgKOH / g or less.

8. The adhesive composition according to claim 1, wherein the weight average molecular weight of the polyamide resin (A) is 5,000 or more and 150,000 or less.

9. The adhesive composition according to claim 1, further comprising an inorganic filler (D).

10. The adhesive composition according to claim 9, wherein the content of the inorganic filler (D) is 10 parts by mass or more and 350 parts by mass or less relative to 100 parts by mass of the total of the content of the polyamide resin (A), the content of the epoxy compound (B), and the content of the polyhydric phenol compound (C).

11. The adhesive composition according to claim 9, wherein the inorganic filler (D) is electrically conductive.

12. A bonding film comprising: 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 claims 1 to 11 or a semi-cured product obtained by partially curing the adhesive composition.

13. A laminate with an adhesive layer, comprising: an adhesive layer; and a substrate 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 11 or a semi-cured product obtained by partially curing the adhesive composition.

14. An electromagnetic wave shielding material having a conductive adhesive layer, wherein the conductive adhesive layer is composed of the adhesive composition according to claim 11, a semi-cured product obtained by partially curing the adhesive composition, or a cured product of the adhesive composition.

15. The electromagnetic wave shielding material according to claim 14, further comprising a protective layer provided on the conductive adhesive layer.

16. A laminate comprising a cured layer made of the cured product of the adhesive composition according to any one of claims 1 to 11.

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