Composite, adhesive using the same, and laminate

Abstract

To provide a polymer, an adhesive and a laminate having superior heat resistance, dielectric properties, and adhesion to a substrate or the like.SOLUTION: The present invention provides a polymer of an ethylenically unsaturated monomer containing an aromatic hydrocarbon (B) having an ethylenically unsaturated bond and / or an alicyclic hydrocarbon (C) having an ethylenically unsaturated bond, the polymer containing a residue of a polyimide (A) having a sulfanyl group as a chain transfer agent. Preferably, the content of the residue of the polyimide (A) having a sulfanyl group is 5-95 mass%.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to a polymer, an adhesive using the same, and a laminate.

Background Art

[0002] In recent years, the electronics field has been developing rapidly. In particular, the miniaturization, weight reduction, and high density of electronic devices have been progressing, and there is an increasing demand for thinning, multi-layerization, and high definition of electronic materials such as printed wiring boards. As adhesives and coating agents used for such electronic materials, for example, the following (1) to (6) can be specifically mentioned.

[0003] (1) Interlayer adhesive: Used to bond circuit boards together and directly contacts copper or silver circuits. It is used between the layers of a multi-layer substrate and exists in liquid or sheet form.

[0004] (2) Adhesive for coverlay film: Used to bond a coverlay film (such as a polyimide film used for protecting the outermost surface of a circuit) and the underlying circuit board. In many cases, the polyimide film and the adhesive layer are integrated in advance.

[0005] (3) Adhesive for copper-clad film (CCL): Used to bond a polyimide film and a copper foil. Processing such as etching is performed during copper circuit formation.

[0006] (4) Coverlay: Used for protecting the outermost surface of a circuit. It is formed by printing on a circuit (printed coverlay), bonding an adhesive sheet (film coverlay), and then curing with light (photosensitive coverlay) or heat.

[0007] (5) Adhesive for reinforcing plate: Used to fix a part of a wiring board to a reinforcing plate such as metal, glass epoxy, or polyimide for the purpose of complementing the mechanical strength of the wiring board.

[0008] (6) Electromagnetic Shield: It mainly consists of an adhesive conductive layer and an insulating layer, and is attached to a flexible printed wiring board for the purpose of shielding electromagnetic noise generated from electronic circuits.

[0009] These forms include liquid (made into ink for printing) and sheet-like (pre-filmed), etc., and the form is appropriately selected according to the application.

[0010] To meet the high requirements for these peripheral members of electronic materials, various polyimide resins are being studied.

[0011] On the other hand, since polyimide resins have low solvent solubility, handling difficulties are cited as an issue, and in recent years, the development of polyimide resins with good solvent solubility and good dielectric properties has been carried out.

[0012] For example, Patent Document 1 discloses that a polyimide with good solvent solubility and good dielectric properties can be synthesized by incorporating a dimer diamine into the polyimide. However, although the polyimide described in Patent Document 1 has high heat resistance, it cannot be said to have sufficient dielectric properties.

[0013] Also, Patent Document 2 discloses a resin composition containing SEBS (styrene-ethylene-butylene-styrene block copolymer) modified with maleic anhydride. However, it has low heat resistance and cannot be said to have sufficient performance.

[0014] Furthermore, Patent Document 3 discloses a polyfunctional vinyl aromatic copolymer containing structural units derived from divinyl aromatic compounds, monovinyl aromatic compounds, and cycloolefin compounds. However, it has poor adhesion (adhesiveness) to the substrate and cannot be said to have sufficient performance.

Prior Art Documents

Patent Documents

[0015]

Patent Document 1

[0016] The problem to be solved by the present invention is to provide a polymer, an adhesive, and a laminate having good heat resistance, dielectric properties, and adhesion to a substrate or the like. [Means for Solving the Problems]

[0017] The present invention relates to the following inventions [1] to [8].

[0018] [1] A polymer of an ethylenically unsaturated monomer containing an aromatic hydrocarbon (B) having an ethylenically unsaturated bond and / or an alicyclic hydrocarbon (C) having an ethylenically unsaturated bond, characterized by containing a residue of a polyimide (A) having a sulfanyl group as a chain transfer agent.

[0019] [2] The polymer according to [1], containing 5 to 95% by mass of a residue of a polyimide (A) having a sulfanyl group.

[0020] [3] The polymer according to [1] or [2], wherein the aromatic compound (B) having an ethylenically unsaturated bond contains an aromatic hydrocarbon having two or more ethylenically unsaturated bonds.

[0021] [4] The polymer according to any one of [1] to [3], wherein the alicyclic hydrocarbon (C) having an ethylenically unsaturated bond contains an alicyclic hydrocarbon having a norbornene skeleton.

[0022] [5] An adhesive containing the polymer according to any one of [1] to [4] and a curing accelerator.

[0023] A laminate comprising an adhesive layer formed from the adhesive described in [6] and [5], and a substrate.

[0024] 〔7〕The laminate according to [6], wherein the substrate comprises a copper foil and / or an insulating layer.

[0025] 〔8〕The laminate according to [6] or [7], which is for a printed wiring board.

Advantages of the Invention

[0026] According to the present invention, it is possible to provide a polymer, an adhesive, and a laminate having good heat resistance, dielectric properties, and adhesion to a substrate or the like.

Modes for Carrying Out the Invention

[0027] Hereinafter, embodiments of the present invention will be described in detail. However, the description of the constituent elements described below is an example (representative example) of an embodiment of the present invention, and the present invention is not limited to these contents as long as it does not exceed the gist thereof.

[0028] <Polyimide (A) having a sulfanyl group> The polyimide (A) having a sulfanyl group used in the present invention is not particularly limited in the synthesis method. For example, it can be obtained by reacting a diamine compound, an aminothiol compound, and a polycarboxylic acid or its anhydride. The number average molecular weight (Mn) of the polyimide having a sulfanyl group is preferably 2,000 or more and 100,000 or less from the viewpoints of dielectric properties and coating suitability. The dielectric properties are better at a molecular weight of 2,000 or more, and the coating suitability is better at 100,000 or less. The mass average molecular weight (Mw) of the polyimide having a sulfanyl group is preferably 5,000 or more and 200,000 or less from the viewpoints of dielectric properties and coating suitability. The dielectric properties are better at a molecular weight of 5,000 or more, and the coating suitability is better at 200,000 or less. The glass transition temperature (Tg) of the polyimide having a sulfanyl group is preferably 10°C or higher and 100°C or lower from the viewpoints of adhesiveness and heat resistance. The heat resistance over time at 150°C is better with a Tg of 10°C or higher, and the adhesiveness is better at 100°C or lower.

[0029] The content ratio of the residue of the polyimide (A) having a sulfanyl group in the polymer is preferably 5 to 95% by mass. When it is 5% by mass or more, the adhesiveness to a substrate or the like and the heat resistance are good, and when it is 95% by mass or less, the dielectric properties are good.

[0030] <Aminothiol compound> The aminothiol compound is a compound having an amino group and a sulfanyl group, and examples include, but are not limited to, the following: aliphatic amines having a sulfanyl group such as aminoalkanethiols like 2-aminoethanethiol, 3-aminopropyl-1-thiol, 1-aminopropyl-2-thiol, 4-amino-1-butanethiol; aromatic amines having a sulfanyl group such as aminobenzenethiols like 2-aminobenzenethiol, 3-aminobenzenethiol, 4-aminobenzenethiol; and cysteine. Among them, aminoalkanethiol is preferable, and 2-aminoethanethiol is more preferable. Two or more kinds of aminothiol compounds may be used.

[0031] <Diamine compound> Examples of the diamine compound used in the present invention include aliphatic diamines, aromatic diamines, alicyclic diamines, etc. Examples of the aliphatic diamine include dimer diamine. Two or more kinds of diamine compounds may be used.

[0032] <Dimer diamine> The diamine compound preferably contains dimer diamine. In this specification, dimer diamine refers to a compound in which all carboxyl groups in a cyclic or acyclic dicarboxylic acid that is a dimer of an unsaturated fatty acid are substituted with primary amino groups. Commercially available dimer diamines include, for example, "Priamine 1071", "Priamine 1073", "Priamine 1074", "Priamine 1075" manufactured by Croda Japan, "Versamine 551" manufactured by BASF Japan, and the like. The dimer diamine can be used alone or in combination of two or more.

[0033] The content of the dimer diamine is preferably 40% by mass or more and 100% by mass or less, more preferably 60% by mass or more and 100% by mass or less in all diamine compounds.

[0034] The diamine compound used in the present invention may contain diamines other than the dimer diamine. Preferred diamines other than the dimer diamine include, but are not limited to, diamine compounds having the following structures.

[0035]

Chemical formula

[0036]

Chemical formula

[0037]

Chemical formula

[0038]

Chemical formula

[0039]

Chemical formula

[0040] <Polycarboxylic acid> The polycarboxylic acid used in the present invention may be in the form of an acid anhydride. Examples of the polycarboxylic acid used in the present invention include 3,3’,4,4’-biphenyltetracarboxylic dianhydride, 2,3,3’,4’-biphenyltetracarboxylic dianhydride, 3,3’,4,4’-diphenylsulfone tetracarboxylic dianhydride, 3,3’,4,4’-benzophenone tetracarboxylic dianhydride, 3,3’,4,4’-diphenyl ether tetracarboxylic dianhydride, 4,4’-[propane-2,2-diylbis(1,4-phenyleneoxy)]diphthalic dianhydride, 2,2-bis(3,3’,4,4’-tetracarboxyphenyl)tetrafluoropropane dianhydride, 2,2-bis(3,4-dicarboxyphenyl)propane dianhydride, 2,2’-bis(3,4-dicarboxyphenoxyphenyl)sulfone dianhydride, 2,2’,3,3’-biphenyltetracarboxylic dianhydride, 2,2-bis(2,3-dicarboxyphenyl)propane dianhydride, pyromellitic dianhydride, 1,2,3,4-benzenetetracarboxylic anhydride, 1,4,5,8-naphthalenetetracarboxylic anhydride, 2,3,6,7-naphthalenetetracarboxylic anhydride, 9,9’-bis[4-(3,4-dicarboxyphenoxy)phenyl]fluorene dianhydride, 9,9’-bis(3,4-dicarboxyphenoxy)fluorene dianhydride, 1’,2’-dianhydride; 4,4’-[4,4’-(propane-2,2-diyl)diphenoxy]diphthalic dianhydride, 1,3,3a,4,5,9b-hexahydro-5(tetrahydro-2,5-dioxo-3-furanyl)naphtho[1,2-C]furan-1,3-dione, and the like. The polycarboxylic acid can be used alone or in combination of two or more.

[0041] Among the polycarboxylic acids, tetracarboxylic acids or tetracarboxylic acid anhydrides are preferred. Further, the polycarboxylic acid preferably has an aliphatic ring or an aromatic ring from the viewpoints of compatibility, adhesiveness, and heat resistance with diamines. Specifically, it preferably contains at least one selected from the group consisting of 2,2-bis(3,3’,4,4’-tetracarboxyphenyl)tetrafluoropropane dianhydride, 9,9’-bis[4-(3,4-dicarboxyphenoxy)phenyl]fluorene dianhydride, 1’,2’-dianhydride, 4,4’-[4,4’-(propan-2,2-diyl)diphenoxy]diphthalic acid dianhydride, 3,3’,4,4’-biphenyltetracarboxylic acid dianhydride, 2,3,3’,4’-biphenyltetracarboxylic acid dianhydride, 1,3,3a,4,5,9b-hexahydro-5(tetrahydro-2,5-dioxo-3-furanyl)naphtho[1,2-C]furan-1,3-dione, etc.

[0042] The reaction between the polycarboxylic acid and the diamine compound can be carried out by a known method. Examples of the solvent used in the reaction include N,N-dimethylformamide (DMF), N,N-dimethylacetamide (DMAc), N-methyl-2-pyrrolidone (NMP), tetrahydrofuran (THF), methyldiglyme, cyclohexanone, 1,4-dioxane, toluene, xylene, mesitylene, solvent naphtha, etc.

[0043] <Ethylenically unsaturated monomer> The ethylenically unsaturated monomer used in the present invention contains an aromatic hydrocarbon (B) having an ethylenically unsaturated bond and / or an alicyclic hydrocarbon (C) having an ethylenically unsaturated bond. The mass average molecular weight (Mw) of the polymer of the polyimide unit (A) and the ethylenically unsaturated monomer is preferably 10,000 or more and 300,000 or less from the viewpoints of dielectric properties and coating suitability. When it is 10,000 or more, the dielectric properties are good, and when it is 300,000 or less, the coating suitability is good.

[0044] Examples of the aromatic hydrocarbon (B) having an ethylenically unsaturated bond include compounds having an aromatic ring and an ethylenically unsaturated bond in the molecule. Although not limited to the following examples, divinylbenzene, styrene, ethylvinylbenzene, 9-vinylacetylene, 1,1-diphenylethylene, 2-vinylnaphthalene, 2-vinylanthracene, indene, etc. can be mentioned. Among them, monocyclic aromatic hydrocarbons having an ethylenically unsaturated bond are preferred from the viewpoint of dielectric properties. Further, from the viewpoint of heat resistance, it is more preferable to contain an aromatic hydrocarbon having two or more ethylenically unsaturated bonds. Specifically, it is preferable to contain styrene, divinylbenzene, ethylvinylbenzene, and more preferably divinylbenzene. These aromatic hydrocarbons (B) having an ethylenically unsaturated bond can be appropriately selected according to the purpose of use, and may be used alone or in combination of two or more.

[0045] Examples of the alicyclic hydrocarbon (C) having an ethylenically unsaturated bond include, but are not limited to, the following examples, such as vinylcyclopentane, vinylcyclohexane, tricyclopentadiene, dicyclopentadiene, cyclopentadiene, etc. Among them, compounds having a norbornene skeleton are preferred from the viewpoint of dielectric properties. For example, 2-norbornene, 5-vinyl-2-norbornene, 5-ethylidene-2-norbornene, norbornadiene, etc. can be mentioned. Among them, from the viewpoint of dielectric properties, bridged-ring (crosslinked) hydrocarbons having an ethylenically unsaturated bond are preferred. Specific examples include 2-norbornene, 5-vinyl-2-norbornene, 5-ethylidene-2-norbornene, norbornadiene. These alicyclic hydrocarbons (C) having an ethylenically unsaturated bond can be appropriately selected according to the purpose of use, and may be used alone or in combination of two or more.

[0046] The polymer of the present invention may contain, as monomer units constituting the polymer, other ethylenically unsaturated monomers other than aromatic hydrocarbons (B) having an ethylenically unsaturated bond or alicyclic hydrocarbons (C) having an ethylenically unsaturated bond. Examples of other ethylenically unsaturated monomers include the following.

[0047] Alkyl (meth) acrylates such as methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, isobutyl (meth) acrylate, pentyl (meth) acrylate, hexyl (meth) acrylate, decyl (meth) acrylate, dodecyl (meth) acrylate, myristyl (meth) acrylate, palmityl (meth) acrylate, stearyl (meth) acrylate, behenyl (meth) acrylate; Aminoalkyl (meth) acrylates such as dimethylaminoethyl (meth) acrylate, dimethylaminopropyl (meth) acrylate, dimethylaminobutyl (meth) acrylate, diethylaminoethyl (meth) acrylate, diethylaminopropyl (meth) acrylate, dipropylaminoethyl (meth) acrylate, dibutylaminoethyl (meth) acrylate; Aminoalkyl (meth) acrylamides such as dimethylaminoethyl (meth) acrylamide, dimethylaminopropyl (meth) acrylamide, dimethylaminobutyl (meth) acrylamide, diethylaminoethyl (meth) acrylamide, diethylaminopropyl (meth) acrylamide, dipropylaminoethyl (meth) acrylamide, dibutylaminoethyl (meth) acrylamide; (Meth) acrylates having an alkylene oxide chain such as polyalkylene glycol mono (meth) acrylate monoalkyl ether; Polydimethylsiloxane (meth) acrylates such as Silaplane FM-0711 and Silaplane FM-0721 (both manufactured by Chisso Corporation) under product names; Product names include fluorine-containing (meth)acrylates such as Cheminox FAAC-4, Cheminox FAAC-6, Cheminox FAMAC-4, Cheminox FAMAC-6 (manufactured by Unimatec), R-1110, R-1210, R-1420, R-1620, R-5210, R-5410, R-5610, M-1110, M-1210, M-1420, M-1620, M-5210, M-5410, M-5610 (manufactured by Daikin), Light Acrylate FA-108 (manufactured by Kyoeisha Chemical), Biscoat-3F, Biscoat-3FM, Biscoat-4F, Biscoat-8F, Biscoat-8FM (manufactured by Osaka Organic Chemical Industry), etc.; Product names include vinyl copolymer macro-monomers such as macro-monomer AA-6 (methyl methacrylate-based macro-monomer), macro-monomer AB-6 (butyl (meth)acrylate-based macro-monomer), macro-monomer AW-6S (isobutyl (meth)acrylate-based macro-monomer), macro-monomer AK-5 (dimethylsiloxane-based macro-monomer) (manufactured by Toagosei), etc.; Product names include (meth)acrylic acid multi-unit type (meth)acrylates such as Biscoat #150D (tetrahydrofurfuryl alcohol oligoacrylate), Biscoat #190D (ethoxydiethylene glycol oligoacrylate) (manufactured by Osaka Organic Chemical Industry), etc.; various (meth)acrylates such as ethoxyethyl (meth)acrylate, ethyl carbitol (meth)acrylate, butoxyethyl (meth)acrylate, cyanoethyl (meth)acrylate, etc. can be mentioned, and in addition to these, vinyl monomers such as vinyl acetate can also be used.

[0048] As other ethylenically unsaturated monomers, from the viewpoint of thermal properties, ethylenically unsaturated monomers having an epoxy group that can form a thermal crosslinking group may be included. Examples of ethylenically unsaturated monomers having an epoxy group include glycidyl (meth)acrylate, methyl glycidyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate glycidyl diether, glycidyl α-ethylacrylate, allyl glycidyl ether, crotonyl glycidyl ether, (iso)crotonic acid glycidyl ether, (3,4-epoxycyclohexyl)methyl (meth)acrylate, and the like.

[0049] From the viewpoints of heat resistance, adhesion, and dielectric properties, the content of the ethylenically unsaturated monomer having an epoxy group and / or a phenolic hydroxyl group that can form a thermal crosslinking group is preferably 1 to 50% by mass, more preferably 1 to 30% by mass, in all the monomers. Other ethylenically unsaturated monomers can be appropriately selected according to the purpose of use, and may be used alone or in combination of two or more.

[0050] Examples of the polymerization initiator used when polymerizing ethylenically unsaturated monomers include organic peroxides such as benzoyl peroxide, tert-butyl perbenzoate, cumene hydroperoxide, diisopropyl peroxydicarbonate, di-n-propyl peroxydicarbonate, di(2-ethoxyethyl) peroxydicarbonate, tert-butyl peroxy-2-ethylhexanoate, tert-butyl peroxyneodecanoate, tert-butyl peroxy pivalate, (3,5,5-trimethylhexanoyl) peroxide, dipropionyl peroxide, diacetyl peroxide, etc., and azo compounds such as 2,2'-azobisisobutyronitrile, 2,2'-azobis(2-methylbutyronitrile), 1,1'-azobis(cyclohexane 1-carbonitrile), 2,2'-azobis(2,4-dimethylvaleronitrile), 2,2'-azobis(2,4-dimethyl-4-methoxyvaleronitrile), dimethyl 2,2'-azobis(2-methylpropionate), 4,4'-azobis(4-cyanovaleric acid), 2,2'-azobis(2-hydroxymethylpropionitrile), 2,2'-azobis[2-(2-imidazolin-2-yl)propane], etc. In addition, an organic boron compound can also be used as an initiator, and examples include diethylmethoxyborane. These polymerization initiators may be used alone or in combination of two or more.

[0051] The solvent is not limited to the following examples, and examples include acetone, methyl ethyl ketone, cyclohexanone, methyl acetate, ethyl acetate, propyl acetate, toluene, xylene, anisole, N,N-dimethylformamide, N,N-dimethylacetamide, N-methylpyrrolidone, N-vinylpyrrolidone, N-methylcaprolactam, dimethyl sulfoxide, tetramethylurea, pyridine, dimethyl sulfone, hexamethyl sulfoxide, m-cresol, γ-butyrolactone, γ-valerolactone, etc. These solvents may be used alone or in combination of two or more.

[0052] <Adhesive> The adhesive of the present invention comprises the polymer of the present invention and a curing accelerator. The mass ratio of the polymer to the curing accelerator is preferably in the range of 99.9:0.01 to 50:50, more preferably in the range of 99:1 to 90:10. Even more preferably, the range of 99:1 to 99:3 is preferred.

[0053] <Curing accelerator> The curing accelerator contained in the adhesive of the present invention is preferably an amine catalyst and / or a compound that generates radicals. For example, as the amine catalyst, non-reactive monoamines such as dimethylcyclohexylamine, N-methyldicyclohexylamine, triethylamine, tripropylamine, tributylamine, N-methylmorpholine, N-ethylmorpholine, N-dimethylbenzylamine, etc., non-reactive diamines such as triethylenediamine, tetramethylhexamethylenediamine, bisdimethylaminoethyl ether, tetramethylpropanediamine, dimethylaminoethylmorpholine, tetramethylethylenediamine, diazabicycloundecene, 2-methyl-1,4-diazabicyclo[2.2.2]octane, etc., non-reactive triamines such as pentamethyldiethylenetriamine, pentamethyldipropylenetriamine, etc., reactive amines such as dimethylethanolamine, N-trioxyethylene-N,N-dimethylamine, N,N-dimethyl-N-hexanolamine, etc. can be mentioned. As the compound that generates radicals, organic peroxides such as benzoyl peroxide, tert-butyl perbenzoate, cumene hydroperoxide, diisopropyl peroxydicarbonate, di-n-propyl peroxydicarbonate, di(2-ethoxyethyl) peroxydicarbonate, tert-butyl peroxy-2-ethylhexanoate, tert-butyl peroxyneodecanoate, tert-butyl peroxyisobutyrate, (3,5,5-trimethylhexanoyl) peroxide, dipropionyl peroxide, diacetyl peroxide, etc., and azo compounds such as 2,2'-azobisisobutyronitrile, 2,2'-azobis(2-methylbutyronitrile), 1,1'-azobis(cyclohexane-1-carbonitrile), 2,2'-azobis(2,4-dimethylvaleronitrile), 2,2'-azobis(2,4-dimethyl-4-methoxyvaleronitrile), dimethyl 2,2'-azobis(2-methylpropionate), 4,4'-azobis(4-cyanovaleric acid), 2,2'-azobis(2-hydroxymethylpropionitrile), 2,2'-azobis[2-(2-imidazolin-2-yl)propane] can be mentioned. These compounds may be used alone or in combination of two or more.

[0054] <organic solvent> The adhesive of the present invention may further contain an organic solvent. The organic solvent is not limited to the following examples, and examples thereof include acetone, methyl ethyl ketone, cyclohexanone, methyl acetate, ethyl acetate, propyl acetate, toluene, xylene, anisole, N,N-dimethylformamide, N,N-dimethylacetamide, N-methylpyrrolidone, N-vinylpyrrolidone, N-methylcaprolactam, dimethyl sulfoxide, tetramethylurea, pyridine, dimethyl sulfone, hexamethyl sulfoxide, m-cresol, γ-butyrolactone, γ-valerolactone, and the like. These solvents may be used alone or in combination of two or more.

[0055] <other additives> The adhesive of the present invention may contain, as other additives, additives such as fillers, flame retardants, antioxidants, ultraviolet absorbers, hydrolysis inhibitors, antifungal agents, thickeners, plasticizers, pigments, and fillers, as needed, and may also contain known catalysts and the like for adjusting the curing reaction.

[0056] <laminate> The laminate of the present invention comprises an adhesive layer formed from the adhesive of the present invention and a base material. For example, it can be used when laminating a copper foil and a support film such as polyimide. For example, the adhesive of the present invention is used to form an adhesive layer on a first base material, or further, a second base material is superposed on the adhesive layer. The base material is not particularly limited, and examples thereof include sheet-like or plate-like ones, and conventionally known plastic films, metal foils, and the like. When two base materials are used, they may be of the same kind or different kinds. The thickness of the adhesive layer is preferably about 3 μm or more and 40 μm or less.

[0057] The laminate of the present invention can also be obtained by impregnating a fibrous substrate with an adhesive, bringing it into a semi-cured (B-staged) state by heating or the like, and then laminating and curing it onto a metal foil or a plastic film. As the fibrous substrate, well-known ones used in various electrical insulation material laminates can be used. Examples of the material include inorganic fibers such as E glass, S glass, low-dielectric glass, and Q glass; organic fibers such as low-dielectric glass polyimide, polyester, and tetrafluoroethylene; and mixtures thereof. In particular, from the viewpoint of dielectric properties, inorganic fibers are preferred, and low-dielectric glass and Q glass are more preferred. When the laminate of the present invention impregnates an adhesive into a fibrous substrate that is a support film, the adhesive forms a continuous adhesive layer, so it becomes a form having a substrate within the adhesive layer, which is one of the usage forms of the laminate of the present invention.

[0058] <Adhesive sheet> A laminate of a support film and an adhesive is also referred to as an adhesive sheet. In addition, in the case where the adhesive impregnates inside the support film and there is no laminated structure, or the adhesive can maintain a sheet shape even without a support film, as long as it is an adhesive sheet, it may be referred to as an adhesive sheet. The adhesive sheet of the present invention can be obtained, for example, as follows. A thermosetting adhesive in a solution or dispersion state is applied to at least one side of a support film and then dried usually at 40 to 150 °C to obtain a thermosetting adhesive sheet in an uncured state (so-called B-stage state) with a support film attached. Then, by covering the other side of the thermosetting adhesive sheet with another support film, a thermosetting adhesive sheet with a support film of the present invention can be obtained. At least one of the support films to be used is preferably a release support film. That is, a thermosetting adhesive in a solution or dispersion state can be applied and dried on a release support film to form a thermosetting adhesive sheet, and then the other side of the thermosetting adhesive sheet can be covered with another release support film, or it can be covered with a non-release support film that becomes an adherend.

[0059] When the adhesive is thermosetting, the adhesive sheet using the same is also referred to as a thermosetting adhesive sheet. Further, the layer made of the adhesive is referred to as a thermosetting adhesive layer. Thermosetting means curing at a temperature of about 40 to 200°C.

[0060] The case of using a thermosetting adhesive sheet with a release substrate, in which one side of the thermosetting adhesive sheet is covered with a release substrate and the other side is covered with a sheet-like substrate (for example, a polyimide film or a polyester film), will be described. The release substrate is peeled off from the thermosetting adhesive sheet with a release substrate. An adherend (for example, the circuit surface side of a printed wiring board having a conductive circuit) is overlaid on the exposed thermosetting adhesive layer. Next, by heating and pressurizing, the thermosetting adhesive layer sandwiched between the sheet-like substrate and the adherend is thermoset, and the thermosetting adhesive layer becomes a sheet-like cured product. In this way, through the sheet-like cured product, the above-mentioned circuit surface of the printed wiring board having a conductive circuit can be protected by a sheet-like substrate (protective sheet), and a printed wiring board with a protective sheet can be obtained. At least one of the support films to be used is preferably a release support film. That is, a thermosetting adhesive in a solution or dispersion state is applied and dried on a release support film to form a thermosetting adhesive sheet, and then the other side of the thermosetting adhesive sheet can be covered with another release support film, or can be covered with a non-release support film serving as an adherend. Alternatively, a thermosetting adhesive in a solution or dispersion state is applied and dried on a non-release support film serving as an adherend to form a thermosetting adhesive sheet, and then the other side of the thermosetting adhesive sheet can be covered with another release sheet-like substrate.

[0061] The dry film thickness of the thermosetting adhesive sheet is preferably 5 to 500 μm, more preferably 10 to 100 μm, in order to exhibit sufficient adhesiveness and solder heat resistance, and from the viewpoint of ease of handling. Examples of the coating method include comma coating, knife coating, die coating, lip coating, roll coating, curtain coating, bar coating, gravure printing, flexographic printing, dip coating, spray coating, spin coating, and the like.

[0062] <Insulating layer> Examples of the insulating layer used include materials called heat-resistant classes. For example, cotton, paper, polyethylene, polyvinyl chloride, natural rubber, epoxy resin, melamine resin, phenolic resin, polyimide film, polyester film, polyphenylene ether film, polyphenylene sulfide film, polystyrene film, polycarbonate film, polyether ether ketone film, polyurethane film, mica, asbestos, inorganic materials such as glass fiber, mica, porcelain, etc. can be mentioned. Examples of the peelable support films include those obtained by subjecting various plastic films and papers to a peeling treatment. Examples of the various plastic films to be subjected to the peeling treatment include polyester film and polyolefin film.

[0063] Next, the case of using a thermosetting adhesive sheet with a peelable substrate in which both sides of the thermosetting adhesive sheet are covered with two peelable substrates will be described. Peel off one of the peelable substrates from the thermosetting adhesive sheet with a peelable substrate. Place an adherend (for example, a polyimide film or a polyester film) on the exposed thermosetting adhesive layer. Peel off the other peelable substrate that covered the other side of the thermosetting adhesive layer. Place another adherend (for example, the circuit surface side of a printed wiring board having a conductive circuit) on the exposed thermosetting adhesive layer. Then, by heating and pressurizing, the thermosetting adhesive layer sandwiched between both adherends is thermoset. After placing the circuit surface side of the printed wiring board having a conductive circuit on the surface from which the peelable substrate was first peeled off, a polyimide film or a polyester film can also be placed on the other side of the thermosetting adhesive layer.

[0064] Examples of the printed wiring board laminate having a conductive circuit (hereinafter also referred to as a wiring board) include a flexible printed wiring board in which a conductive circuit is formed on a flexible and insulating plastic film such as polyester or polyimide. As a method for providing a conductive circuit, for example, a photosensitive etching resist layer is formed on a copper foil of a flexible copper-clad laminate formed by providing a copper foil on a base film with or without an adhesive layer, and the photosensitive etching resist layer is exposed through a mask film having a circuit pattern, only the exposed portion is cured, and then the remaining resist layer is peeled off after removing the unexposed copper foil by etching, etc., so that a conductive circuit can be formed from the copper foil. Alternatively, a method of providing only the necessary circuits on the base film by means such as sputtering or plating can also be mentioned. Alternatively, a method of forming a conductive circuit on a base film by using a conductive ink containing silver or copper particles and by a printing technique can also be mentioned.

[0065] <Multi-layering of a plurality of flexible printed wirings> The thermosetting adhesive sheet of the present invention is suitably used for manufacturing a printed wiring board with a protective sheet, and can also be used as follows. By sandwiching the thermosetting adhesive sheet of the present invention between a plurality of flexible printed wirings and heating and pressing, the thermosetting adhesive sheet can be cured to obtain a multi-layer flexible printed wiring board.

[0066] <Lamination of a base film and a copper foil for a flexible printed wiring board> For example, by sandwiching the thermosetting adhesive sheet of the present invention between a polyimide film and a copper foil and heating and pressing, the thermosetting adhesive sheet can also be cured.

[0067] <Conductive adhesive sheet> The thermosetting adhesive sheet of the present invention can be used as a conductive thermosetting adhesive sheet in which a thermosetting composition obtained by blending and dispersing a conductive metal filler such as copper or silver and a conductive filler such as carbon in addition to a polyimide resin, a curing agent, and a specific amount of an alkali metal compound is formed into a sheet shape.

[0068] <Electromagnetic wave shielding> Furthermore, the thermosetting adhesive sheet of the present invention can also be used as an electromagnetic wave shield by forming a multilayer structure with an insulating layer using the conductive thermosetting adhesive sheet prepared above. In addition, not only the conductive layer portion, but the thermosetting adhesive sheet of the present invention can also be used as an insulating layer.

[0069] <Thermal Conductive Adhesive Sheet> Furthermore, the thermosetting adhesive sheet of the present invention can be used as a thermally conductive thermosetting adhesive sheet in which a thermally conductive inorganic filler, a metal filler, etc. are dispersed and blended in addition to the polyimide resin, the curing agent, and a specific amount of an alkali metal compound, and the resulting thermosetting composition is formed into a sheet.

Examples

[0070] Hereinafter, the present invention will be described more specifically with reference to Examples and Comparative Examples. In the Examples and Comparative Examples, "parts" and "%" mean parts by mass and mass%, respectively, unless otherwise specified.

[0071] <Measurement Method of Number Average Molecular Weight (Mn) and Mass Average Molecular Weight (Mw)> The measurements of Mn and Mw were performed using GPC (gel permeation chromatography) "HPC-8020" manufactured by Tosoh Corporation. GPC is a liquid chromatography that separates and quantifies a substance dissolved in a solvent (THF; tetrahydrofuran) based on the difference in its molecular size. In the measurement of the present invention, two columns of "LF-604" (manufactured by Showa Denko KK: GPC column for rapid analysis: 6 mm ID × 150 mm size) were connected in series, and the measurement was performed under the conditions of a flow rate of 0.6 ml / min and a column temperature of 40°C. The determination of Mn and Mw was performed in terms of polystyrene conversion with known Mn and Mw.

[0072] <Measurement of Glass Transition Temperature (Tg)> Tg was measured using "Differential Scanning Calorimeter DSC-60 PLUS" manufactured by Shimadzu Corporation under the conditions of a starting temperature of 25°C, an ending temperature of 250°C, and a heating rate of 10.0°C / min. After heating to the ending temperature for the first time, it was rapidly cooled to the starting temperature, and the peak value when measured under the same conditions thereafter was defined as Tg.

[0073] The materials used in the examples and their abbreviations are as follows. MED-J: 4,4'-Diamino-3,3'-diethyl-5,5'-dimethyldiphenylmethane Product name: Curehard MED-J (manufactured by Kumiai Chemical Co., Ltd.) Dimer diamine: Product name: Priamine 1075 (manufactured by Croda Japan Co., Ltd.) 6FDA: 2,2-Bis(3,3',4,4'-tetracarboxyphenyl)hexafluoropropane dianhydride Manufactured by Wakayama Seika Kogyo Co., Ltd. TDA100: 1,3,3a,4,5,9b-Hexahydro-5(tetrahydro-2,5-dioxo-3-furanyl)naphtho[1,2-c]furan-1,3-dione Product name: Rica Sid TDA-100 (manufactured by Shin Nippon Rika Co., Ltd.) BISDA: 1',2'-Dianhydride; 4,4'-[4,4'-(propan-2,2-diyl)diphenoxy]diphthalic acid dianhydride Manufactured by SABIC Japan Co., Ltd. Parkmill D: Dicumyl peroxide Product name: Parkmill (registered trademark) D (manufactured by NOF Corporation)

[0074] (Synthesis Example 1) Production of polyimide (SHP-1) Into a reaction vessel equipped with a stirrer, thermometer, reflux condenser, dropping funnel, and nitrogen gas inlet tube, 990 parts of N,N-dimethylformamide and 461 parts of 6FDA were charged, and the temperature was raised to 100 °C while stirring under a nitrogen stream. After dropping 529 parts of dimer diamine over 1 hour, 9 parts of 2-aminoethanethiol was dropped, the temperature was raised to 140 °C, and a dehydration reaction was carried out for 14 hours. After raising the temperature to 200 °C while removing the solvent, 990 parts of toluene was added to adjust the solid content concentration to 50%. SHP-1, a polyimide (A) having a sulfanyl group with Mn 14,239 and Mw 29,233, was obtained.

[0075] (Synthesis Examples 2 to 7) Polyimides SHP-2 to SHP-7 having a sulfanyl group were obtained in the same manner as in Synthesis Example 1, except that the types and amounts of the materials were changed according to Synthesis Examples 2 to 7 of Table 1. The Mn, Mw, and Tg of the obtained polyimides are shown in Table 1. In Table 1, the numerical values represent parts unless otherwise specified, and the blanks indicate that they are not blended.

[0076] (Example 1) Synthesis of Polymer (SHEP-1) Into a reaction vessel equipped with a stirrer, thermometer, reflux condenser, dropping funnel, and nitrogen gas inlet tube, 33 parts of the polyimide (SHP-1) solution produced in Synthesis Example 1 (solid content concentration: 50%), 70 parts of styrene, 57 parts of divinylbenzene, 105 parts of 2-norbornene, 166 parts of butyl acetate, and 331 parts of toluene were charged, and the temperature was raised to 70°C with stirring under a nitrogen stream. 2.0 parts of diethylmethoxyborane was charged, and the reaction was carried out for 5 hours and then cooled to 25°C. Thereafter, an aqueous sodium hydrogen carbonate solution was added to stop the reaction. After removing the aqueous layer by liquid separation, the oil layer was stirred at 70°C under reduced pressure. The yield of the obtained polymer (SHEP-1) was 111 parts (yield: 44.8%). This polymer contained 14.82% of the residue of the polyimide (A) having a sulfanyl group. Mn was 18,400 and Mw was 102,100. Toluene was appropriately added to adjust the solid content concentration to 50%.

[0077] (Examples 2 to 12) Synthesis of Polymers (SHEP-2 to SHEP-12) Polymers (SHEP-2 to SHEP-12) were obtained in the same manner as in Example 1, except that the materials and formulations described in Table 2 were changed. The Mn and Mw of the obtained polymers are shown in Table 2. In Table 2, the numerical values represent parts unless otherwise specified, and the blanks indicate that they are not blended.

[0078] (Comparative Example 1) Into a reaction vessel equipped with a stirrer, thermometer, reflux condenser, dropping funnel, and nitrogen gas inlet tube, 70 parts of styrene, 57 parts of divinylbenzene, 105 parts of 2-norbornene, 155 parts of butyl acetate, 309 parts of toluene, and 47 parts of 2,4-diphenyl-4-methyl-1-pentene as a chain transfer agent were charged, and the temperature was raised to 70 °C while stirring under a nitrogen stream. 1.9 parts of diethylmethoxyborane was charged, and the reaction was carried out for 5 hours and then cooled to 25 °C. Thereafter, an aqueous sodium hydrogen carbonate solution was added to stop the reaction. After removing the aqueous layer by liquid separation, the oil layer was stirred at 70 °C under reduced pressure. The yield of the obtained polymer (SHEP-13) was 112 parts (yield 43.0%). Mn was 10,277 and Mw was 23,612. Toluene was appropriately added to adjust the solid content concentration to 50%.

[0079] (Comparative Example 2) Into a reaction vessel equipped with a stirrer, thermometer, reflux condenser, dropping funnel, and nitrogen gas inlet tube, 70 parts of styrene, 57 parts of divinylbenzene, 105 parts of 2-norbornene, 155 parts of butyl acetate, 309 parts of toluene, and 41.2 parts of tert-dodecyl mercaptan as a chain transfer agent were charged, and the temperature was raised to 70 °C while stirring under a nitrogen stream. 1.9 parts of diethylmethoxyborane was charged, and the reaction was carried out for 5 hours and then cooled to 25 °C. Thereafter, an aqueous sodium hydrogen carbonate solution was added to stop the reaction. After removing the aqueous layer by liquid separation, the oil layer was stirred at 70 °C under reduced pressure. The yield of the obtained polymer (SHEP-14) was 115 parts (yield 42.0%). Mn was 11,651 and Mw was 18,894. Toluene was appropriately added to adjust the solid content concentration to 50%.

[0080] [Example 13] 30 parts of a polymer (SHEP-1) solution (solid content concentration 50%) and 0.3 part of Parkmill D as a curing accelerator were mixed to obtain an adhesive. This adhesive was uniformly coated on a polyester film subjected to a peeling treatment using a blade coater so that the film thickness after drying was 50 μm, and pre-dried at 100 °C for 20 minutes, and then the polyester film after drying was peeled off to obtain an adhesive sheet.

[0081] [Examples 14 to 24, Comparative Examples 3 and 4] An adhesive sheet was obtained in the same manner as in Example 1 except that the materials and compounding amounts described in Table 3 were used.

[0082] (Production of Adhesive Sheet with Copper Foil Substrate) On one surface of the adhesive sheet immediately after pre-drying in Example 13, the treated surface of an 18-μm-thick electrolytic copper foil (trade name "F2-WS", manufactured by Furukawa Circuit Foil Co., Ltd.) was overlaid, and then heated and pressed under vacuum at a pressure of 10 MPa, 180 °C, and for 1 minute using a vacuum press molding machine, and further heated at 200 °C for 2 hours to produce an adhesive sheet with a substrate, which is a laminate.

[0083] (Production of Adhesive Sheet with Polyimide Film Substrate) The adhesives of Examples 13 to 24 and Comparative Examples 3 and 4 were respectively applied with a blade coater between polyimide films with a thickness of 75 μm ["Kapton (registered trademark) 300H" manufactured by Toray DuPont Co., Ltd.] so that the thickness after drying would be 30 μm, and then heated at 150 °C for 30 minutes under vacuum using a vacuum press molding machine to obtain an adhesive sheet with a polyimide film substrate, which is a laminate.

[0084] (Production of Laminate) After overlaying the treated surface of an electrolytic copper foil (F2-WS) on the adhesive surface of the adhesive sheet with a polyimide film substrate, it was laminated at 80 °C, and then pressure-bonded at 200 °C and 1.0 MPa for 2 hours using a vacuum press machine to produce a laminate.

[0085] (Adhesiveness) Test pieces with a width of 10 mm and a length of 65 mm were cut out from the above laminate, and a T-peel test was performed at a tensile speed of 300 mm / min in an atmosphere of 23 °C and 50% relative humidity to measure the adhesive strength (N / cm). This test evaluates the adhesive strength of the adhesive layer during normal temperature use, and the results were judged according to the following criteria. ◎: Adhesive strength of 2.5 N / 3 mm or more (very good) ○: Adhesive strength of 2.0 N / 3 mm or more and less than 2.5 N / 3 mm (good) △: Adhesive strength of 1.0 N / 3 mm or more and less than 2.0 N / 3 mm (usable) ×: Peel strength less than 1.0 N / 3 mm (not usable)

[0086] <Heat resistance> Similar to the above adhesion test, test pieces cut to a width of 10 mm and a length of 65 mm were stored in an air atmosphere at 150 °C for 1000 hours. After taking them out, the adhesion strength was measured in the same manner as above. The reduction rate of the adhesion strength with respect to the adhesion strength measured in the above <Adhesion> was judged according to the following criteria. ◎ ··· Reduction rate less than 20% (very good) ○ ··· Reduction rate 20% or more and less than 50% (good) △ ··· Reduction rate 50% or more and less than 80% (usable) × ··· Reduction rate 80% or more (not usable)

[0087] <Dielectric properties> (Relative permittivity) Three test pieces cut to a width of 10 mm and a length of 65 mm were set in the relative permittivity measuring device "ADMS01Oc" manufactured by AET Co., Ltd. The relative permittivity at a measurement temperature of 23 °C and a measurement frequency of 10 GHz was obtained by the cavity resonator method and evaluated according to the following criteria. ◎: Relative permittivity less than 2.5 (very good) ○: Relative permittivity 2.5 or more and less than 2.6 (good) △: Relative permittivity 2.6 or more and less than 2.7 (usable) ×: Relative permittivity 2.7 or more (not usable)

[0088] (Dielectric tangent) Three test pieces cut to a width of 10 mm and a length of 65 mm were set in the relative permittivity measuring device "ADMS01Oc" manufactured by AET Co., Ltd. The dielectric tangent at a measurement temperature of 23 °C and a measurement frequency of 10 GHz was obtained by the cavity resonator method and evaluated according to the following criteria. ◎: Dielectric tangent less than 0.002 (very good) ○: Dielectric tangent 0.002 or more and less than 0.003 (good) △: Dielectric tangent 0.003 or more and less than 0.005 (usable) ×: Dielectric tangent 0.005 or more (not usable)

[0089] As shown in Table 3, the adhesive obtained from the thermosetting composition of the present invention is excellent in dielectric properties such as relative permittivity and dielectric loss tangent, and has high adhesion and long-term heat resistance. In particular, Examples 13 to 22 containing 5 to 95% of the residue of polyimide (A) having a sulfanyl group showed excellent dielectric properties compared to Example 23 in which the content of the residue of polyimide (A) exceeded 95%, and showed excellent adhesion and long-term heat resistance compared to Example 24 in which the content of the residue of polyimide (A) was less than 5%. Among them, Examples 13 to 17 and 19 to 22 containing an aromatic hydrocarbon having two or more ethylenically unsaturated bonds as the aromatic compound (B) having an ethylenically unsaturated bond had good long-term heat resistance. Also, Examples 13 to 20 and 22 having a norbornene skeleton in the alicyclic hydrocarbon (C) having an ethylenically unsaturated bond had good dielectric properties. In particular, Examples 13 to 17 and 19 to 21 containing both an aromatic hydrocarbon having two or more ethylenically unsaturated bonds and an alicyclic hydrocarbon having a norbornene skeleton were excellent in dielectric properties, adhesiveness, and long-term heat resistance.

[0090] (Fabrication of Printed Wiring Board) The adhesive according to Example 13 was applied to a Kapton (R) H type with a blade coater so that the thickness after drying was 30 μm, and dried at 100 °C for 3 minutes to obtain an adhesive sheet. Next, the treated surface of the electrolytic copper foil (F2-WS) was overlapped with the adhesive surface of the adhesive sheet, pressed with a laminating roll at 100 °C, and then treated at 150 °C for 30 minutes under vacuum with a vacuum press molding machine to obtain a laminate. The copper surface of this laminate was subjected to soft etching treatment to form a copper circuit, and further, the adhesive resin surface of the adhesive sheet with a base material obtained by the above method was overlapped thereon, and heated and pressed under vacuum at a pressure of 10 MPa, 180 °C, and 1 minute with a vacuum press molding machine, and then further heated at 200 °C for 2 hours, whereby a flexible printed wiring board could be fabricated. It was also confirmed that flexible printed wiring boards could be fabricated in the same manner for the adhesive compositions of other examples.

[0091]

Table 1

[0092]

Table 2

[0093]

Table 3

Claims

1. A polymer of an ethylenically unsaturated monomer containing an aromatic hydrocarbon (B) having an ethylenically unsaturated bond and / or an alicyclic hydrocarbon (C) having an ethylenically unsaturated bond, which contains the residue of a polyimide (A) having a sulfanyl group as a chain transfer agent, and wherein the aromatic compound (B) having an ethylenically unsaturated bond contains an aromatic hydrocarbon having two or more ethylenically unsaturated bonds.

2. The polymer according to Claim 1, which contains 5 to 95% by mass of the residue of the polyimide (A) having a sulfanyl group.

3. The polymer according to Claim 1 or 2, wherein the alicyclic hydrocarbon (C) having an ethylenically unsaturated bond contains an alicyclic hydrocarbon having a norbornene skeleton.

4. An adhesive containing the polymer according to any one of Claims 1 to 3 and a curing accelerator.

5. A laminate comprising an adhesive layer formed from the adhesive according to Claim 4 and a substrate.

6. The laminate according to Claim 5, wherein the substrate comprises a copper foil and / or an insulating layer.

7. The laminate according to Claim 5 or 6, which is for a printed wiring board.

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