Polyimide resin composition, adhesive composition, film-like adhesive material, adhesive sheet, resin-coated copper foil, copper-clad laminate, printed wiring board, and polyimide film

Abstract

To provide a polyimide resin composition that allows an organic solvent to easily volatilize during drying with heating, even when an organic solvent containing a nitrogen atom and an aromatic hydrocarbon are not used, and gives a polyimide resin layer having low dielectric constants and low dielectric loss tangents, and excellent solder heat resistance.SOLUTION: A polyimide resin composition contains a polyimide (A), which is a reactant of a monomer group containing an aromatic tetracarboxylic acid anhydride (a1) and a diamine containing a dimer diamine (a2), and two or more different organic solvents (B). The component (B) includes an ester (B1) and at least one organic solvent (B2) selected from the group consisting of a ketone, an ether, an aliphatic hydrocarbon and an alicyclic hydrocarbon.SELECTED DRAWING: None

Description

[Technical field]

[0001] The present invention relates to a polyimide resin composition, an adhesive composition, a film-like adhesive, an adhesive sheet, a resin-coated copper foil, a copper-clad laminate, a printed wiring board, and a polyimide film. [Background technology]

[0002] Flexible printed wiring boards (FPWBs), printed circuit boards (PCBs), and multilayer wiring boards using them are widely used in products such as mobile communication devices such as mobile phones and smartphones, their base station equipment, network-related electronic devices such as servers and routers, and large computers.

[0003] Furthermore, in recent years, these products have begun to use high-frequency electrical signals to transmit and process large volumes of information at high speed. However, because high-frequency signals are highly susceptible to attenuation, there has been a demand for methods to minimize transmission loss in the multilayer wiring boards.

[0004] One possible means for reducing transmission loss in multilayer wiring boards is to use a polyimide resin as an adhesive composition having properties such that both the dielectric constant and dielectric tangent are small (hereinafter also referred to as low dielectric properties) when laminating printed wiring boards or printed circuit boards.

[0005] As such polyimides, resins having tetracarboxylic acid residues and diamine residues derived from dimer acid for forming adhesive layers in metal-clad laminates having an insulating resin layer, an adhesive layer, and a metal layer are known (Patent Document 1). The polyimides have aromatic rings, and therefore exhibit excellent solder heat resistance.

[0006] Incidentally, in the production of FPWB and the like, a process is carried out in which an adhesive composition is applied to a support such as release polyethylene terephthalate (release PET) or release paper and dried under heating. However, since such supports have poor heat resistance, the drying is usually carried out at a temperature of 150°C or less. On this premise, N-methylpyrrolidone (NMP) and xylene are used as organic solvents in the production of the polyimide of Patent Document 1. However, since organic solvents containing nitrogen atoms such as NMP have a high boiling point, they tend to remain when the resin composition is dried at the above temperature, and are likely to adversely affect the low dielectric properties and solder heat resistance of the polyimide resin layer. In addition, aromatic hydrocarbons such as xylene are harmful to the human body and the environment, and are therefore not preferred for use. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] JP 2018-140544 A Summary of the Invention [Problem to be solved by the invention]

[0008] The present invention aims to provide a polyimide resin composition which, when dried under heating, allows an organic solvent to be easily volatilized without using an organic solvent containing a nitrogen atom or an aromatic hydrocarbon, and which gives a polyimide resin layer having a low dielectric constant, a low dielectric tangent, and excellent solder heat resistance. [Means for solving the problem]

[0009] The present inventors have conducted extensive research to solve the above problems, and have found that a specific combination of organic solvents can solve the above problems, thereby completing the present invention.

[0010] 1. A polyimide resin composition comprising a polyimide (A) which is a reaction product of a monomer group including an aromatic tetracarboxylic anhydride (a1) and a diamine (a2) including a dimer diamine, and two or more different organic solvents (B), The component (B) is a polyimide resin composition comprising an ester (B1) and at least one organic solvent (B2) selected from the group consisting of ketones, ethers, aliphatic hydrocarbons, and alicyclic hydrocarbons.

[0011] 2. The polyimide resin composition according to item 1 above, wherein the component (a2) further contains an alicyclic diamine and / or an aromatic diamine.

[0012] 3. The polyimide resin composition according to item 1 or 2 above, wherein the content ratio of the components (B1) and (B2) is, in terms of mass ratio, (B1) / (B2)=10 / 90 to 90 / 10.

[0013] 4. The polyimide resin composition according to any one of items 1 to 3 above, wherein the component (B) does not contain an aromatic hydrocarbon.

[0014] 5. The polyimide resin composition according to any one of items 1 to 4 above, wherein the component (B1) is an aliphatic ester.

[0015] 6. An adhesive composition comprising the polyimide resin composition according to any one of items 1 to 5 above and a crosslinking agent.

[0016] 7. A film-like adhesive comprising a cured product of the adhesive composition described in the preceding item 6.

[0017] 8. An adhesive sheet having the film-like adhesive material according to item 7 above on at least one side of a support film.

[0018] 9. A resin-coated copper foil comprising the film-like adhesive described in the preceding paragraph 7 and copper foil.

[0019] 10. A copper-clad laminate comprising the resin-coated copper foil according to item 9 above and a copper foil or an insulating sheet.

[0020] 11. A printed wiring board having a circuit pattern on the copper foil surface of the copper-clad laminate described in the preceding paragraph 10.

[0021] 12. A polyimide film which is a cured product of the polyimide resin composition according to any one of items 1 to 5 above. Effect of the Invention

[0022] According to the polyimide resin composition of the present invention, even without using an organic solvent containing a nitrogen atom or an aromatic hydrocarbon, an organic solvent is easily volatilized when dried under heating, and a polyimide resin layer having a low dielectric constant, a low dielectric tangent, and excellent solder heat resistance is provided. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0023] The polyimide resin composition of the present invention contains a polyimide (A) (hereinafter referred to as component (A)) which is a reaction product of a monomer group including an aromatic tetracarboxylic anhydride (a1) (hereinafter referred to as component (a1)) and a diamine (a2) (hereinafter referred to as component (a2)) containing a dimer diamine.

[0024] The component (a1) is not particularly limited, and examples thereof include 2,2',3,3'-biphenyltetracarboxylic dianhydride, 2,3',3,4'-biphenyltetracarboxylic dianhydride, 3,3',4,4'-biphenyltetracarboxylic dianhydride, pyromellitic dianhydride, 1,2,3,4-benzenetetracarboxylic anhydride, 3,3',4,4'-diphenylsulfonetetracarboxylic dianhydride, 4,4'-oxydiphthalic anhydride, 4,4'-[propane-2,2-diylbis(1,4-phenyleneoxy)]diphthalic anhydride, and the like. Acid dianhydrides, 2,2',3,3'-benzophenone tetracarboxylic dianhydride, 2,3,3',4'-benzophenone tetracarboxylic dianhydride, 3,3',4,4'-benzophenone tetracarboxylic dianhydride, 2,3',3,4'-diphenyl ether tetracarboxylic dianhydride, bis(2,3-dicarboxyphenyl)ether dianhydride, bis(2,3-dicarboxyphenyl)methane dianhydride, bis(3,4-dicarboxyphenyl)methane dianhydride, 1,1-bis(2,3-dicarboxyphenyl)ethene dianhydride 1,1-bis(3,4-dicarboxyphenyl)ethane dianhydride, 2,2-bis(2,3-dicarboxyphenyl)propane dianhydride, 2,2-bis(3,4-dicarboxyphenyl)propane dianhydride, bis(2,3-dicarboxyphenoxyphenyl)sulfone dianhydride, bis(3,4-dicarboxyphenoxyphenyl)sulfone dianhydride, 1,4,5,8-naphthalenetetracarboxylic anhydride, 2,3,6,7-naphthalenetetracarboxylic anhydride, 2,3,6,7-anthracenetetracarboxylic anhydride Examples of the dianhydride include 1,2,5,6-naphthalenetetracarboxylic dianhydride, 1,4,5,8-naphthalenetetracarboxylic dianhydride, 2,3,6,7-naphthalenetetracarboxylic dianhydride, 4,8-dimethyl-1,2,3,5,6,7-hexahydronaphthalene-1,2,5,6-tetracarboxylic dianhydride, 2,2-bis(3,4-dicarboxyphenyl)hexafluoropropane dianhydride, and 2,2-bis(3,3',4,4'-tetracarboxyphenyl)tetrafluoropropane dianhydride. These may be used alone or in combination of two or more.

[0025] Among these, the component (a1) is preferably one represented by the following general formula (1) from the viewpoints of the flexibility and solder heat resistance of the polyimide resin layer. [ka] (In formula (1), p -OCO-, or -COO-H2C-HC(-OC(=O)-CH3)-CH2-OCO-, and p represents an integer of 1 to 20.

[0026] Examples of the compound represented by the general formula (1) include 2,2',3,3'-biphenyltetracarboxylic dianhydride, 3,3',4,4'-biphenyltetracarboxylic dianhydride, 3,3',4,4'-diphenylsulfonetetracarboxylic dianhydride, 3,3',4,4'-benzophenonetetracarboxylic dianhydride, 3,3',4,4'-diphenylethertetracarboxylic dianhydride, 2,2-bis(3,4-dicarboxyphenyl)hexafluoropropane, and the like. Examples of the dianhydride include tetrafluoropropane dianhydride, 2,2-bis(3,3',4,4'-tetracarboxyphenyl)tetrafluoropropane dianhydride, 4,4'-[propane-2,2-diylbis(1,4-phenyleneoxy)]diphthalic dianhydride, 2,2-bis(2,3-dicarboxyphenyl)propane dianhydride, 2,2-bis(3,4-dicarboxyphenyl)propane dianhydride, and 2,2'-bis(3,4-dicarboxyphenoxyphenyl)sulfone dianhydride. These may be used alone or in combination of two or more. Among them, 2,2-bis(3,4-dicarboxyphenyl)hexafluoropropane dianhydride and 4,4'-[propane-2,2-diylbis(1,4-phenyleneoxy)]diphthalic dianhydride are preferred because the (A) component dissolves well in organic solvents.

[0027] The amount of the component (a1) used in 100 mol % of the monomers constituting the component (A) is not particularly limited, but is usually 10 to 90 mol %, and preferably 25 to 75 mol %.

[0028] The amount of the tetracarboxylic acid anhydride represented by the general formula (1) used in 100 mol % of the monomer group constituting the component (A) is not particularly limited, but is usually 10 to 90 mol %, and preferably 25 to 75 mol %.

[0029] The amount of the tetracarboxylic acid anhydride represented by the general formula (1) used in 100 mol % of the component (a1) is not particularly limited, but is usually 10 to 100 mol %, preferably 50 to 100 mol %.

[0030] The component (a2) is a diamine containing a dimer diamine.

[0031] Dimer diamine is a dimer acid in which all carboxyl groups have been replaced with primary amino groups or primary aminomethyl groups (see, for example, JP-A-9-12712). Here, dimer acid mainly includes a dibasic acid having 36 carbon atoms obtained by dimerizing unsaturated fatty acids such as oleic acid, linoleic acid, and linolenic acid, and includes a monomer acid having 18 carbon atoms, a trimer acid having 54 carbon atoms, and a polymerized fatty acid having 20 to 90 carbon atoms depending on the degree of purification. The dimer acid includes a double bond, and the degree of unsaturation may be reduced by, for example, a hydrogenation reaction.

[0032] The dimer diamine is not particularly limited, and examples thereof include those represented by the following general formula (2): In general formula (2), m+n is preferably 6 to 17, p+q is preferably 8 to 19, and the dashed line represents a carbon-carbon single bond or a carbon-carbon double bond.

[0033] [ka]

[0034] Commercially available dimer diamine products include "VERSAMINE 551" and "VERSAMINE 552" (both manufactured by Cognics Japan, Inc.), "PRIAMINE 1073", "PRIAMINE 1074", and "PRIAMINE 1075" (all manufactured by Croda Japan, Inc.).

[0035] Furthermore, the dimer diamine may be used as it is, or may be used after being subjected to a purification treatment such as distillation.

[0036] The amount of dimer diamine used in 100 mol % of the monomers constituting the component (A) is not particularly limited, but is usually 5 mol % or more, and preferably 25 to 75 mol %.

[0037] The amount of dimer diamine used in 100 mol % of the component (a2) is not particularly limited, but is usually 10 mol % or more, and preferably 30 to 100 mol %.

[0038] The (a2) component may also contain a diamine (a2-1) other than dimer diamine (hereinafter referred to as (a2-1) component). The (a2-1) component may also contain, for example, an aliphatic diamine, an alicyclic diamine, an aromatic diamine, a diaminoether, or a diaminopolysiloxane. Note that these amines exclude dimer diamine.

[0039] Examples of the aliphatic diamine include ethylenediamine, 1,3-diaminopropane, 1,4-diaminobutane, 1,5-diaminopentane, 1,6-diaminohexane, 1,7-diaminoheptane, 1,8-diaminooctane, 1,9-diaminononane, 1,10-diaminodecane, 1,11-diaminoundecane, and 1,12-diaminododecane.

[0040] Examples of alicyclic diamines include diaminocyclohexane, diaminodicyclohexylmethane, dimethyldiaminodicyclohexylmethane, diaminodicyclohexylpropane, tetramethyldiaminodicyclohexylmethane, 1,3-bis(aminomethyl)cyclohexane, 1,4-bis(aminomethyl)cyclohexane, diaminobicyclo[2.2.1]heptane, bis(aminomethyl)-bicyclo[2.2.1]heptane, 3(4),8(9)-bis(aminomethyl)tricyclo[5.2.1.0(2,6)]decane, and isophoronediamine.

[0041] Examples of aromatic diamines include: diaminobiphenyls such as 2,2'-diaminobiphenyl, 3,3'-diaminobiphenyl, 4,4'-diaminobiphenyl, 2,2'-dimethyl-4,4'-diaminobiphenyl, 2,2'-diethyl-4,4'-diaminobiphenyl, and 2,2'-di-n-propyl-4,4'-diaminobiphenyl; Bisaminophenoxyphenylpropanes such as 2,2-bis[4-(3-aminophenoxy)phenyl]propane and 2,2-bis[4-(4-aminophenoxy)phenyl]propane; diaminodiphenyl ethers such as 3,3'-diaminodiphenyl ether, 3,4'-diaminodiphenyl ether, and 4,4'-diaminodiphenyl ether; Phenylenediamines such as p-phenylenediamine and m-phenylenediamine; Diaminodiphenyl sulfides such as 3,3'-diaminodiphenyl sulfide, 3,4'-diaminodiphenyl sulfide, and 4,4'-diaminodiphenyl sulfide; diaminodiphenyl sulfones such as 3,3'-diaminodiphenyl sulfone, 3,4'-diaminodiphenyl sulfone, and 4,4'-diaminodiphenyl sulfone; Diaminobenzophenones such as 3,3'-diaminobenzophenone, 3,4'-diaminobenzophenone, and 4,4'-diaminobenzophenone; Diaminodiphenylmethanes such as 3,3'-diaminodiphenylmethane, 3,4'-diaminodiphenylmethane, 4,4'-diaminodiphenylmethane, and bis[4-(3-aminophenoxy)phenyl]methane; Diaminophenylpropanes such as 2,2-di(3-aminophenyl)propane, 2,2-di(4-aminophenyl)propane, and 2-(3-aminophenyl)-2-(4-aminophenyl)propane; diaminophenylhexafluoropropanes such as 2,2-di(3-aminophenyl)-1,1,1,3,3,3-hexafluoropropane, 2,2-di(4-aminophenyl)-1,1,1,3,3,3-hexafluoropropane, and 2-(3-aminophenyl)-2-(4-aminophenyl)-1,1,1,3,3,3-hexafluoropropane; Diaminophenylphenylethanes such as 1,1-di(3-aminophenyl)-1-phenylethane, 1,1-di(4-aminophenyl)-1-phenylethane, and 1-(3-aminophenyl)-1-(4-aminophenyl)-1-phenylethane; bisaminophenoxybenzenes such as 1,3-bis(3-aminophenoxy)benzene, 1,3-bis(4-aminophenoxy)benzene, 1,4-bis(3-aminophenoxy)benzene, and 1,4-bis(4-aminophenoxy)benzene; Bisaminobenzoylbenzenes such as 1,3-bis(3-aminobenzoyl)benzene, 1,3-bis(4-aminobenzoyl)benzene, 1,4-bis(3-aminobenzoyl)benzene, and 1,4-bis(4-aminobenzoyl)benzene; Bisaminodimethylbenzylbenzenes such as 1,3-bis(3-amino-α,α-dimethylbenzyl)benzene, 1,3-bis(4-amino-α,α-dimethylbenzyl)benzene, 1,4-bis(3-amino-α,α-dimethylbenzyl)benzene, and 1,4-bis(4-amino-α,α-dimethylbenzyl)benzene; bisaminoditrifluoromethylbenzylbenzenes such as 1,3-bis(3-amino-α,α-ditrifluoromethylbenzyl)benzene, 1,3-bis(4-amino-α,α-ditrifluoromethylbenzyl)benzene, 1,4-bis(3-amino-α,α-ditrifluoromethylbenzyl)benzene, and 1,4-bis(4-amino-α,α-ditrifluoromethylbenzyl)benzene; Aminophenoxybiphenyls such as 4,4'-bis(3-aminophenoxy)biphenyl, 4,4'-bis(4-aminophenoxy)biphenyl, and bis[1-(3-aminophenoxy)]biphenyl; Aminophenoxyphenyl ketones such as bis[4-(3-aminophenoxy)phenyl]ketone and bis[4-(4-aminophenoxy)phenyl]ketone; Aminophenoxyphenyl sulfides such as bis[4-(3-aminophenoxy)phenyl]sulfide and bis[4-(4-aminophenoxy)phenyl]sulfide; Aminophenoxyphenyl sulfones such as bis[4-(3-aminophenoxy)phenyl]sulfone and bis[4-(4-aminophenoxy)phenyl]sulfone; Aminophenoxyphenyl ethers such as bis[4-(3-aminophenoxy)phenyl]ether and bis[4-(4-aminophenoxy)phenyl]ether; aminophenoxyphenylpropanes such as 2,2-bis[4-(3-aminophenoxy)phenyl]propane, 2,2-bis[3-(3-aminophenoxy)phenyl]-1,1,1,3,3,3-hexafluoropropane, and 2,2-bis[4-(4-aminophenoxy)phenyl]-1,1,1,3,3,3-hexafluoropropane; Bis(aminophenoxybenzoyl)benzenes such as 1,3-bis[4-(3-aminophenoxy)benzoyl]benzene, 1,3-bis[4-(4-aminophenoxy)benzoyl]benzene, 1,4-bis[4-(3-aminophenoxy)benzoyl]benzene, and 1,4-bis[4-(4-aminophenoxy)benzoyl]benzene; Bis(aminophenoxy-α,α-dimethylbenzyl)benzenes such as 1,3-bis[4-(3-aminophenoxy)-α,α-dimethylbenzyl]benzene, 1,3-bis[4-(4-aminophenoxy)-α,α-dimethylbenzyl]benzene, 1,4-bis[4-(3-aminophenoxy)-α,α-dimethylbenzyl]benzene, and 1,4-bis[4-(4-aminophenoxy)-α,α-dimethylbenzyl]benzene; Bis[(aminoaryloxy)benzoyl]diphenyl ethers such as 4,4'-bis[4-(4-aminophenoxy)benzoyl]diphenyl ether; Bis(amino-α,α-dimethylbenzylphenoxy)benzophenones such as 4,4'-bis[4-(4-amino-α,α-dimethylbenzyl)phenoxy]benzophenone: Bis[amino-α,α-dimethylbenzylphenoxy]diphenyl sulfones such as 4,4'-bis[4-(4-amino-α,α-dimethylbenzyl)phenoxy]diphenyl sulfone; Bis[aminophenoxyphenoxy]diphenyl sulfones such as 4,4'-bis[4-(4-aminophenoxy)phenoxy]diphenyl sulfone; Diaminodiaryloxybenzophenones such as 3,3'-diamino-4,4'-diphenoxybenzophenone and 3,3'-diamino-4,4'-dibiphenoxybenzophenone; Diaminoaryloxybenzophenones such as 3,3'-diamino-4-phenoxybenzophenone and 3,3'-diamino-4-biphenoxybenzophenone; Examples thereof include 1-(4-aminophenyl)-2,3-dihydro-1,3,3-trimethyl-1H-inden-5-amine and 9,9-bis(4-aminophenyl)fluorene.

[0042] Examples of diamino ethers include bis(aminomethyl)ether, bis(2-aminoethyl)ether, bis(3-aminopropyl)ether, bis[(2-aminomethoxy)ethyl]ether, bis[2-(2-aminoethoxy)ethyl]ether, bis[2-(3-aminoprotoxy)ethyl]ether, 1,2-bis(aminomethoxy)ethane, 1,2-bis(2-aminoethoxy)ethane, 1,2-bis[2-(aminomethoxy)ethoxy]ethane, 1,2-bis[2-(2-aminoethoxy)ethoxy]ethane, ethylene glycol bis(3-aminopropyl)ether, diethylene glycol bis(3-aminopropyl)ether, and triethylene glycol bis(3-aminopropyl)ether.

[0043] Examples of diaminopolysiloxanes include α,ω-bis(2-aminoethyl)polydimethylsiloxane, α,ω-bis(3-aminopropyl)polydimethylsiloxane, α,ω-bis(4-aminobutyl)polydimethylsiloxane, α,ω-bis(5-aminopentyl)polydimethylsiloxane, α,ω-bis[3-(2-aminophenyl)propyl]polydimethylsiloxane, and α,ω-bis[3-(4-aminophenyl)propyl]polydimethylsiloxane.

[0044] These (a2-1) components may be used alone or in combination of two or more. Among them, alicyclic diamines and aromatic diamines are preferred, and aromatic diamines are more preferred, in that the polyimide resin layer exhibits excellent solder heat resistance.

[0045] There are no particular limitations on the amount of the component (a2-1) used in 100 mol % of the monomers constituting the component (A), but it is usually no more than 90 mol %, and preferably no more than 50 mol %.

[0046] The amount of the (a2-1) component used in 100 mol % of the (a2) component is not particularly limited, but is usually 90 mol % or less, and preferably 70 mol % or less.

[0047] The component (A) of the present invention can be obtained by various known production methods. Examples of the production method include a step of polyaddition reacting a monomer group including the components (a1) and (a2) at a temperature of preferably about 30 to 120°C, more preferably about 40 to 100°C, for a time of preferably about 0.1 to 2 hours, more preferably about 0.1 to 0.5 hours to obtain a polyaddition product, and a step of imidizing the obtained polyaddition product at a temperature of preferably about 80 to 250°C, more preferably about 80 to 170°C, for preferably about 0.5 to 50 hours, more preferably about 1 to 20 hours, i.e., a dehydration ring-closing reaction. The method and order of mixing the components (a1) and (a2) are not particularly limited.

[0048] In the imidization reaction step, various known reaction catalysts, dehydrating agents, and an organic solvent (B) described below may be used, and these may be used alone or in combination of two or more kinds.

[0049] Examples of the reaction catalyst include aliphatic tertiary amines such as triethylamine, aromatic tertiary amines such as dimethylaniline, and heterocyclic tertiary amines such as pyridine, picoline, and isoquinoline. Examples of the dehydrating agent include aliphatic carboxylic acid anhydrides such as acetic anhydride, and aromatic carboxylic acid anhydrides such as benzoic anhydride.

[0050] When an organic solvent (B) described below is used during the production of the component (A), the amount used is adjusted so that the reaction concentration becomes 5 to 60% by mass, and preferably 20 to 50% by mass.

[0051] The imide ring closure rate of the component (A) is not particularly limited, but is preferably from 90 to 100%, and more preferably about 95 to 100%, in order to obtain a component (A) that has both a high softening point and high flexibility. It is presumed that when the imide ring closure rate of component (A) is within the above range, component (A) is more likely to form a hard segment and soft segment structure, and thus has a higher softening point and flexibility. Here, the "imide ring closure rate" refers to the content of cyclic imide bonds in the polyimide resin of component (A), and can be determined by various spectroscopic means such as NMR or IR analysis.

[0052] The physical properties of the component (A) are not particularly limited. The weight average molecular weight of the component (A) is preferably 20,000 to 100,000. The number average molecular weight of the component (A) is preferably 5,000 to 50,000. The weight average molecular weight and number average molecular weight are determined as polystyrene equivalent values ​​measured by, for example, gel permeation chromatography (GPC).

[0053] The softening point of the component (A) of the present invention is preferably about 50 to 250° C., more preferably about 80 to 200° C., from the viewpoint of facilitating processing by press hardening during the production of laminates such as copper-clad laminates. The softening point refers to the temperature at which the storage modulus begins to decrease in the profile of the storage modulus measured using a commercially available measuring device (product name "ARES-2KSTD-FCO-STD", manufactured by Rheometric Scientific Co., Ltd.) or the like.

[0054] The polyimide resin composition of the present invention contains two or more different organic solvents (B) (hereinafter referred to as component (B)).

[0055] The content of the (B) component in the polyimide resin composition of the present invention is not particularly limited, but is preferably 50 to 1,000 parts by mass (in terms of non-volatile content) and more preferably 100 to 400 parts by mass (in terms of non-volatile content) per 100 parts by mass of the polyimide resin composition.

[0056] The component (B) contains an ester (B1) (hereinafter referred to as the component (B1)) and at least one organic solvent (B2) (hereinafter referred to as the component (B2)) selected from the group consisting of ketones, ethers, aliphatic hydrocarbons, and alicyclic hydrocarbons.

[0057] As the (B1) component, various known esters can be used. Specific examples include aliphatic esters, alicyclic esters, and aromatic esters. The aliphatic esters herein mean esters that do not have a cyclic structure, and include alkyl carbonate esters such as dimethyl carbonate and diethyl carbonate. Among them, the (B1) component preferably has a boiling point of 60°C or higher and 150°C or lower. When the (B1) component has the above boiling point, the (B1) component does not volatilize when the polyimide resin composition or the adhesive composition containing the composition is applied to the support film or copper foil, so that uneven coating and voids can be prevented. In addition, the (B1) component is easily volatilized when the coating layer of the composition is dried, so that the (B1) component does not remain in the obtained cured layer, and as a result, the (B1) component also exhibits low dielectric properties. The upper and lower limits of the boiling point include 145, 140, 135, 130, 125, 120, 115, 110, 105, 100, 95, 90, 85, 80, 75, 70, and 65. For the same reasons as above, the (B1) component preferably has a boiling point of 70° C. or higher and 140° C. or lower. The boiling points are values ​​at normal pressure, and are listed in the catalogs of chemical manufacturers and Chemical Book (hereinafter the same).

[0058] Of the preferable (B1) components, examples of aliphatic esters include n-propyl formate (80° C.), isopropyl formate (68° C.), n-butyl formate (106° C.), isobutyl formate (98° C.), sec-butyl formate (99° C.), tert-butyl formate (82° C.), n-pentyl formate (130° C.), isopentyl formate (124° C.), ethyl acetate (77° C.), n-propyl acetate (102° C.), acetic acid, Isopropyl acetate (89°C), n-butyl acetate (126°C), isobutyl acetate (118°C), sec-butyl acetate (112°C), tert-butyl acetate (97°C), n-pentyl acetate (149°C), isopentyl acetate (142°C), sec-pentyl acetate (121°C), tert-pentyl acetate (123°C), methyl propionate (80°C), ethyl propionate (99°C), propionic acid n-Propyl (123°C), isopropyl propionate (108°C), n-butyl propionate (145°C), isobutyl propionate (138°C), sec-butyl propionate (133°C), tert-butyl propionate (118°C), methyl butyrate (102°C), ethyl butyrate (121°C), n-propyl butyrate (143°C), isopropyl butyrate (129°C), methyl isobutyrate (92°C) °C), ethyl isobutyrate (112 °C), n-propyl isobutyrate (134 °C), isopropyl isobutyrate (120 °C), isobutyl isobutyrate (147 °C), sec-butyl isobutyrate (112 °C), methyl valerate (126 °C), ethyl valerate (145 °C), methyl hexanoate (150 °C), dimethyl carbonate (90 °C), ethyl methyl carbonate (107 °C), diethyl carbonate (126 °C), etc. The temperatures in parentheses indicate the boiling points of each compound under normal pressure (same below).

[0059] Of the preferable components (B1), examples of alicyclic esters include methyl cyclopropanecarboxylate (119° C.), ethyl cyclopropanecarboxylate (131° C.), and methyl cyclobutanecarboxylate (135° C.).

[0060] These (B1) components may be used alone or in combination of two or more. Among them, from the viewpoint of good compatibility between the (A) component and the (B1) component, aliphatic esters are preferred, and n-butyl acetate and diethyl carbonate are more preferred.

[0061] As the (B2) component, various known ketones, ethers, aliphatic hydrocarbons, and alicyclic hydrocarbons can be used. These (B2) components may be used alone or in combination of two or more. Among them, the (B2) component preferably has a boiling point of 60°C or more and 150°C or less. When the (B2) component has the above boiling point, the (B2) component does not volatilize when the polyimide resin composition or the adhesive composition containing the composition is applied to a support film or copper foil, so that uneven coating and voids can be prevented. In addition, since the (B2) component is easily volatilized when the coating layer of the composition is dried, the (B2) component does not remain in the obtained cured layer, and as a result, low dielectric properties are also exhibited. The upper and lower limits of the boiling point include 145, 140, 135, 130, 125, 120, 115, 110, 105, 100, 95, 90, 85, 80, 75, 70, and 65, etc. For the same reasons as above, the boiling point of the (B2) component is more preferably 70°C or higher and 140°C or lower.

[0062] Of the preferable components (B2), examples of ketones include methyl ethyl ketone (80° C.), methyl-n-propyl ketone (102° C.), methyl isopropyl ketone (93° C.), n-butyl methyl ketone (127° C.), isobutyl methyl ketone (116° C.), sec-butyl methyl ketone (116° C.), tert-butyl methyl ketone (106° C.), diethyl ketone (101° C.), ethyl-n-propyl ketone (123° C.), and the like. ketones such as ethyl isopropyl ketone (115°C), n-butyl ethyl ketone (147°C), ethyl isobutyl ketone (136°C), tert-butyl ethyl ketone (125°C), di-n-propyl ketone (145°C); and alicyclic ketones such as cyclopropyl methyl ketone (114°C), cyclobutanone (99°C), cyclobutyl methyl ketone (138°C), cyclopentanone (131°C). These may be used alone or in combination of two or more.

[0063] Of the preferred (B2) components, examples of ethers include aliphatic monoethers such as ethyl-n-propyl ether (62°C), di-n-propyl ether (90°C), isopropyl-n-propyl ether (83), and diisopropyl ether (69°C); aliphatic diethers such as 1,2-dimethoxyethane (85°C), 1,1-diethoxyethane (103°C), 1,2-diethoxyethane (121°C), 1,2-dimethoxypropane (96°C), 2,2-dimethoxypropane (80°C), 1,1-diethoxypropane (123°C), and 2,2-diethoxypropane (113°C); aliphatic triethers such as triethoxymethane (143°C) and 1,1,1-trimethoxyethane (107°C); and alicyclic monoethers such as methoxycyclopentane (106°C) and methoxycyclohexane (135°C). These may be used alone or in combination of two or more.

[0064] Of the preferable (B2) components, examples of the aliphatic hydrocarbons include n-alkanes such as n-hexane (69°C), n-heptane (94°C), and n-octane (126°C); monoalkyl alkanes such as 2-methylpentane (60°C), 3-ethylpentane (93°C), 2-methylhexane (90°C), 3-methylhexane (92°C), 3-ethylhexane (118°C), 2-methylheptane (116°C), 3-methylheptane (120°C), 4-methylheptane (117°C), 3-ethylheptane (143°C), 2-methyloctane (143°C), 3-methyloctane (144°C), and 4-methyloctane (142°C). dialkyl alkanes such as 2,2-dimethylpentane (79°C), 2,4-dimethylpentane (80°C), 2,2-dimethylhexane (106°C), 2,3-dimethylhexane (115°C), 2,4-dimethylhexane (108°C), 2,5-dimethylhexane (108°C), 4-ethyl-2-methylhexane (134°C), 2,2-dimethylheptane (133°C), 2,3-dimethylheptane (140°C), 2,4-dimethylheptane (133°C), 2,5-dimethylheptane (136°C), 3,3-dimethylheptane (137°C), and 3,4-dimethylheptane (140°C). These may be used alone or in combination of two or more.

[0065] Among the preferred (B2) components, examples of alicyclic hydrocarbons include cycloalkanes such as cyclohexane (81°C) and cycloheptane (118°C); monoalkylcycloalkanes such as ethylcyclobutane (70°C), methylcyclopentane (72°C), ethylcyclopentane (103°C), n-propylcyclopentane (131°C), isopropylcyclopentane (126°C), isobutylcyclopentane (148°C), methylcyclohexane (101°C), ethylcyclohexane (132°C), and methylcycloheptane (145°C); and dialkylcycloalkanes such as 1,1-dimethylcyclohexane (118°C) and 1-ethyl-3-methylcyclohexane (150°C). These may be used alone or in combination of two or more.

[0066] Among these components (B2), it is preferable to include ethers and alicyclic hydrocarbons from the viewpoint of good compatibility between the components (A) and (B2).

[0067] The content ratio of the component (B1) and the component (B2) in the production of the component (A) is preferably (B1) / (B2)=10 / 90 to 90 / 10, more preferably 15 / 85 to 85 / 15, and even more preferably 20 / 80 to 80 / 20, from the viewpoints of being able to well dissolve the polyamic acid and polyimide resin produced and to remove the by-produced water.

[0068] [Adhesive composition] The adhesive composition of the present invention contains the polyimide resin composition of the present invention and a crosslinking agent.

[0069] The content of the polyimide resin composition in the adhesive composition of the present invention is not particularly limited, but is preferably about 10 to 99.5% by mass, with the adhesive composition being 100% by mass.

[0070] The content of component (A) in the adhesive composition of the present invention is not particularly limited, but is preferably about 2 to 98 mass % relative to 100 mass % of the nonvolatile content of the adhesive composition.

[0071] The crosslinking agent can be any known agent that functions as a crosslinking agent for polyimide without any particular limitation. The crosslinking agent may be used alone or in combination of two or more. The crosslinking agent is preferably at least one selected from the group consisting of epoxide, benzoxazine, bismaleimide, and cyanate ester.

[0072] Examples of the epoxide include phenol novolac type epoxides, cresol novolac type epoxides, bisphenol A type epoxides, bisphenol F type epoxides, bisphenol S type epoxides, hydrogenated bisphenol A type epoxides, hydrogenated bisphenol F type epoxides, stilbene type epoxides, triazine skeleton-containing epoxides, fluorene skeleton-containing epoxides, linear aliphatic epoxides, alicyclic epoxides, glycidylamine type epoxides, triphenolmethane type epoxides, alkyl-modified triphenolmethane type epoxides, biphenyl type epoxides, dicyclopentadiene skeleton-containing epoxides, naphthalene skeleton-containing epoxides, aryl alkylene type epoxides, tetraglycidylxylylenediamine, dimer acid-modified epoxides which are dimer acid-modified products of the above epoxides, and dimer acid diglycidyl esters. In addition, examples of commercially available epoxides include "jER828", "jER834", "jER807", "jER604", and "jER630" manufactured by Mitsubishi Chemical Corporation, "ST-3000" manufactured by Nippon Steel Chemical & Material Co., Ltd., "Celloxide 2021P" manufactured by Daicel Corporation, "YD-172-X75" manufactured by Nippon Steel Chemical & Material Co., Ltd., and "TETRAD-X" manufactured by Mitsubishi Gas Chemical Co., Ltd. Among these, from the viewpoint of the balance between solder heat resistance and low dielectric properties, at least one selected from the group consisting of bisphenol A type epoxide, bisphenol F type epoxide, hydrogenated bisphenol A type epoxide, and alicyclic epoxide is preferable.

[0073] In particular, tetraglycidyldiamine of the general formula (3) [ka] (In the formula, Z represents a phenylene group or a cyclohexylene group.) has good compatibility with the polyimide. In addition, the use of this makes it easy to achieve a low loss elastic modulus for the adhesive layer, and also improves the solder heat resistance and low dielectric properties.

[0074] When an epoxide is used as a crosslinking agent, various known epoxide curing agents and active ester curing agents can be used in combination. These curing agents can be used alone or in combination of two or more.

[0075] Examples of the curing agent for epoxides include acid anhydride curing agents such as succinic anhydride, phthalic anhydride, maleic anhydride, trimellitic anhydride, pyromellitic anhydride, hexahydrophthalic anhydride, 3-methylhexahydrophthalic anhydride, 4-methyl-hexahydrophthalic anhydride, or a mixture of 4-methylhexahydrophthalic anhydride and hexahydrophthalic anhydride, tetrahydrophthalic anhydride, methyl-tetrahydrophthalic anhydride, nadic anhydride, methylnadic anhydride, norbornane-2,3-dicarboxylic anhydride, methylnorbornane-2,3-dicarboxylic anhydride, methylcyclohexene dicarboxylic anhydride, 3-dodecenylsuccinic anhydride, and octenylsuccinic anhydride; Amine-based curing agents such as dicyandiamide (DICY), aromatic diamines (product names "Lonzacure M-DEA", "Lonzacure M-DETDA", etc., both manufactured by Lonza Japan Ltd.), and aliphatic amines; phenolic hardeners such as phenol novolac resin, cresol novolac resin, bisphenol A type novolac resin, triazine modified phenol novolac resin, and phenolic hydroxyl group-containing phosphazene (product name "SPH-100" manufactured by Otsuka Chemical Co., Ltd., etc.); Rosin-based hardeners such as maleic acid-modified rosin and its hydrogenates; Examples thereof include cyclic phosphazene compounds.

[0076] Examples of active ester-based curing agents include those containing a dicyclopentadienyldiphenol structure described in JP 2019-183071 A, those containing a naphthalene structure, acetylated phenol novolac, and benzoylated phenol novolac. Commercially available active ester curing agents include, for example: Those containing a dicyclopentadienyldiphenol structure, such as "EXB9451", "EXB9460", "EXB9460S", "HPC-8000", "HPC-8000H", "HPC-8000-65T", "HPC-8150-62T", "HPC-8000H-65MT", "HPC-8000L-65MT", "EXB-8000L", "EXB-8000L-65MT", and "EXB-8150-65T" (all manufactured by DIC Corporation); Those containing a naphthalene structure include "EXB9416-70BK" (DIC Corporation); An acetylated phenol novolac, "DC808" (Mitsubishi Chemical Corporation); Benzoyl compounds of phenol novolak include "YLH1026", "YLH1030", and "YLH1048" (manufactured by Mitsubishi Chemical Corporation).

[0077] The active ester-based curing agent may be produced by any of a variety of known methods. Examples of such an active ester-based curing agent include those obtained by reacting a polyfunctional phenol compound with an aromatic carboxylic acid, as described in Japanese Patent No. 5152445.

[0078] Among the curing agents, active ester curing agents and phenolic curing agents are preferred, and active ester curing agents are particularly preferred. The amount of the curing agent used is not particularly limited, but is preferably about 0.1 to 40% by mass, and more preferably about 1 to 10% by mass, based on 100% by mass of the non-volatile content of the adhesive composition.

[0079] In addition, when an epoxide and a curing agent for epoxide are used in combination as a crosslinking agent, a reaction catalyst can be further used in combination. The reaction catalyst may be used alone or in combination of two or more. Examples of the reaction catalyst include tertiary amines such as 1,8-diaza-bicyclo[5.4.0]undecene-7, triethylenediamine, benzyldimethylamine, triethanolamine, dimethylaminoethanol, and tris(dimethylaminomethyl)phenol; imidazoles such as 2-methylimidazole, 2-phenylimidazole, 2-phenyl-4-methylimidazole, and 2-heptadecylimidazole; organic phosphines such as tributylphosphine, methyldiphenylphosphine, triphenylphosphine, diphenylphosphine, and phenylphosphine; and tetraphenylboron salts such as tetraphenylphosphonium tetraphenylborate, 2-ethyl-4-methylimidazole tetraphenylborate, and N-methylmorpholine tetraphenylborate. The amount of the reaction catalyst used is not particularly limited, but is preferably about 0.01 to 5% by mass, based on 100% by mass of the non-volatile content of the adhesive composition.

[0080] Examples of benzoxazine include 6,6-(1-methylethylidene)bis(3,4-dihydro-3-phenyl-2H-1,3-benzoxazine) and 6,6-(1-methylethylidene)bis(3,4-dihydro-3-methyl-2H-1,3-benzoxazine). The nitrogen of the oxazine ring may be bonded to a phenyl group, a methyl group, a cyclohexyl group, or the like. Commercially available benzoxazine products include "Benzoxazine Fa type" and "Benzoxazine Pd type" manufactured by Shikoku Chemical Industry Co., Ltd., and "RLV-100" manufactured by Air Water Corporation.

[0081] Examples of bismaleimides include 4,4'-diphenylmethane bismaleimide, m-phenylene bismaleimide, bisphenol A diphenyl ether bismaleimide, 3,3'-dimethyl-5,5'-diethyl-4,4'-diphenylmethane bismaleimide, 4-methyl-1,3-phenylene bismaleimide, 1,6'-bismaleimide-(2,2,4-trimethyl)hexane, 4,4'-diphenyl ether bismaleimide, 4,4'-diphenylsulfone bismaleimide, etc. Commercially available bismaleimides include "BAF-BMI" manufactured by JFE Chemical Co., Ltd. and "BMI-1000H" manufactured by Daiwa Chemical Industry Co., Ltd.

[0082] Examples of the cyanate ester include 2-allylphenol cyanate ester, 4-methoxyphenol cyanate ester, 2,2-bis(4-isocyanatophenyl)-1,1,1,3,3,3-hexafluoropropane, bisphenol A cyanate ester, diallyl bisphenol A cyanate ester, 4-phenylphenol cyanate ester, 1,1,1-tris(4-cyanatophenyl)ethane, 4-cumylphenol cyanate ester, 1,1-bis(4-cyanatophenyl)ethane, 4,4'-bisphenol cyanate ester, and 2,2-bis(4-cyanatophenyl)propane. Examples of commercially available cyanate esters include "PRIMASET BTP-6020S" manufactured by Lonza Japan Co., Ltd.

[0083] The content of the crosslinking agent in the adhesive composition of the present invention is not particularly limited, and is preferably about 1 to 900 parts by mass per 100 parts by mass (non-volatile content) of the component (A) of the present invention in the adhesive composition.

[0084] The content of the crosslinking agent in the adhesive composition of the present invention is preferably about 1 to 80 mass % based on 100 mass % of the nonvolatile content of the adhesive composition.

[0085] The adhesive composition of the present invention may contain a flame retardant. The flame retardant may be used alone or in combination of two or more. Examples of the flame retardant include phosphorus-based flame retardants and inorganic fillers.

[0086] Examples of phosphorus-based flame retardants include polyphosphoric acid, phosphoric acid esters, and phosphazene derivatives that do not have a phenolic hydroxyl group. Among the phosphazene derivatives, cyclic phosphazene derivatives are preferred in terms of flame retardancy, heat resistance, bleed-out resistance, etc. Commercially available cyclic phosphazene derivatives include "SPB-100" manufactured by Otsuka Chemical Co., Ltd. and "Ravitor FP-300B" manufactured by Fushimi Pharmaceutical Co., Ltd.

[0087] Examples of inorganic fillers include silica fillers, phosphorus-based fillers, fluorine-based fillers, and inorganic ion exchanger fillers. The silica filler may be one whose surface has been modified with a treatment agent such as a silane coupling agent. Commercially available inorganic fillers include "FB-3SDC" and "SFP-20M" manufactured by Denka Co., Ltd., "SC-2500-SPJ", "SC-2500-SXJ", and "SC-2500-SVJ" manufactured by Admatechs Co., Ltd., "Exolit OP935" manufactured by Clariant Chemicals Co., Ltd., "KTL-500F" manufactured by Kitamura Co., Ltd., and "IXE" manufactured by Toagosei Co., Ltd.

[0088] The content of the flame retardant in the adhesive composition of the present invention is not particularly limited, and is preferably 1 to 150 parts by mass per 100 parts by mass (non-volatile content) of the component (A) of the present invention in the adhesive composition.

[0089] The adhesive composition of the present invention includes a compound having the general formula: W-Si(R 1 ) a (OR 2 ) 3-a (Wherein, W represents a group containing a functional group reactive with an acid anhydride group, R 1 represents a hydrogen atom or a hydrocarbon group having 1 to 8 carbon atoms; R 2represents a hydrocarbon group having 1 to 8 carbon atoms, and a represents 0, 1, or 2. The reactive alkoxysilyl compound can adjust the melt viscosity of the adhesive layer made of the adhesive composition of the present invention while maintaining the low dielectric properties. As a result, the interfacial adhesion between the adhesive layer and the support (the so-called anchor effect) can be increased, while the exudation of the cured layer from the edge of the support can be suppressed.

[0090] Examples of the reactive functional group contained in W in the above general formula include an amino group, an epoxy group, and a thiol group.

[0091] Examples of compounds in which W contains an amino group include N-2-(aminoethyl)-3-aminopropylmethyldimethoxysilane, N-2-(aminoethyl)-3-aminopropyltrimethoxysilane, 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, and 3-ureidopropyltrialkoxysilane. Examples of compounds in which W contains an epoxy group include 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, and 3-glycidoxypropyltriethoxysilane. Examples of compounds in which W contains a thiol group include 3-mercaptopropyltrimethoxysilane, 3-mercaptopropyltriethoxysilane, 3-mercaptopropylmethyldimethoxysilane, and 3-mercaptopropylmethyldiethoxysilane. Among these, compounds in which W contains an amino group are preferred because of their good reactivity and flow control effects.

[0092] The content of the reactive alkoxysilyl compound in the adhesive composition of the present invention is not particularly limited, and the content of the reactive alkoxysilyl compound is preferably 0.01 to 5 parts by mass per 100 parts by mass (in terms of non-volatile content) of the component (A) of the present invention in the adhesive composition.

[0093] The adhesive composition of the present invention may contain an additive other than the polyimide resin composition of the present invention, a crosslinking agent, a flame retardant, a reactive alkoxysilyl compound, and the above-mentioned organic solvents.

[0094] Examples of the additives include ring-opening esterification reaction catalysts, dehydrating agents, plasticizers, weathering agents, antioxidants, heat stabilizers, lubricants, antistatic agents, brightening agents, colorants, conductive agents, release agents, surface treatment agents, viscosity adjusters, silica fillers, and fluorine fillers.

[0095] The content of the additive is not particularly limited, but examples thereof include less than 1 part by mass, less than 0.1 part by mass, less than 0.01 part by mass, 0 part by mass, etc., per 100 parts by mass of the nonvolatile content of the adhesive composition.

[0096] The content of the additive is not particularly limited, but examples of the content include less than 1 part by mass, less than 0.1 part by mass, less than 0.01 part by mass, 0 part by mass, etc. per 100 parts by mass of the (A) component of the present invention (converted into non-volatile content).

[0097] The adhesive composition of the present invention can be obtained by dissolving the crosslinking agent, and, if necessary, the flame retardant, the reactive alkoxysilyl compound, and the additives in the polyimide resin composition of the present invention. In preparing the adhesive composition, the above-mentioned component (B) may be further blended.

[0098] [Film adhesive] The film-like adhesive of the present invention includes a cured product of the adhesive composition of the present invention. Examples of a method for producing a film-like adhesive include a method including a step of applying the adhesive composition to a suitable support, a step of curing the adhesive composition by heating to volatilize the organic solvent, and a step of peeling off the support. The thickness of the adhesive is not particularly limited, but is preferably about 3 to 40 μm. Examples of the support include release paper, release film, and a support film described below. In addition, when producing the film-like adhesive, the adhesive composition may be used in combination with various known adhesive compositions other than the adhesive.

[0099] [Adhesive sheet] The adhesive sheet of the present invention comprises a support film and the film-like adhesive of the present invention on at least one surface of the support film.

[0100] The adhesive sheet can be obtained, for example, by applying the adhesive composition of the present invention onto a support film and curing it by heating, or by laminating the film-like adhesive of the present invention onto a support film.

[0101] Examples of the support film include polyimide, polyester, polyimide-silica hybrid, polyethylene, polypropylene, polyethylene terephthalate, polyethylene naphthalate, polymethyl methacrylate resin, polystyrene resin, polycarbonate resin, acrylonitrile-butadiene-styrene resin, ethylene terephthalate, aromatic polyester resin obtained from phenol, phthalic acid, hydroxynaphthoic acid, etc. and parahydroxybenzoic acid (so-called liquid crystal polymer; manufactured by Kuraray Co., Ltd., "Vexstar", etc.), cycloolefin polymer, fluorine-based resin (polytetrafluoroethylene (PTFE), perfluoroalkoxyalkane (PFA), polyvinylidene fluoride (PVDF), etc.), etc. Polyimide includes the polyimide film of the present invention.

[0102] When the adhesive composition of the present invention is applied to the support film, the application method is not particularly limited, and examples thereof include coating with a coater such as a comma, die, knife, or lip coater. The thickness of the coating layer is also not particularly limited, but the thickness after drying is preferably about 1 to 100 μm, more preferably about 3 to 50 μm. The adhesive layer of the adhesive sheet may be protected with various protective films.

[0103] [Resin-coated copper foil] The resin-coated copper foil of the present invention includes the film-like adhesive of the present invention and copper foil. Specifically, the adhesive composition of the present invention is applied to a copper foil and then heat-cured, or the film-like adhesive of the present invention is laminated to a copper foil. Examples of the copper foil include rolled copper foil and electrolytic copper foil, and those that have been subjected to various surface treatments (roughening, rust prevention, etc.) can also be used. Examples of the rust prevention treatment include so-called mirror-finishing treatments such as plating treatment using a plating solution containing Ni, Zn, Sn, etc., and chromate treatment.

[0104] The thickness of the copper foil is not particularly limited, and is preferably about 1 to 100 μm, and more preferably about 2 to 38 μm. As the coating means, the above-mentioned methods can be mentioned.

[0105] The adhesive layer or film-like adhesive of the resin-coated copper foil may be uncured or may be partially or completely cured under heating. The partially cured adhesive layer or film-like adhesive is in a state called B stage. The thickness of the adhesive layer or film-like adhesive is not particularly limited, and is preferably about 0.5 to 30 μm. A resin may be further laminated to the copper foil of the resin-coated copper foil to form a double-sided resin-coated copper foil.

[0106] [Copper-clad laminate] The copper-clad laminate of the present invention includes the resin-coated copper foil of the present invention and a copper foil or insulating sheet. The copper-clad laminate is also called CCL (Copper Clad Laminate). Specifically, the copper-clad laminate is a laminate in which the resin-coated copper foil is pressed under heat onto at least one or both sides of various known copper foils or insulating sheets. When laminating onto one side, a material different from the resin-coated copper foil may be pressed onto the other side. In addition, the number of resin-coated copper foils, copper foils, and insulating sheets in the copper-clad laminate is not particularly limited.

[0107] In one embodiment, the insulating sheet is preferably a prepreg or the support film. The prepreg refers to a sheet-like material in which a reinforcing material such as glass cloth is impregnated with a resin and cured to the B stage (JIS C 5603). The resin is an insulating resin such as the component (A) of the present invention, a phenol resin, an epoxy resin, a polyester resin, a liquid crystal polymer, or an aramid resin. The thickness of the insulating sheet is not particularly limited, and is preferably about 20 to 500 μm. The heating and pressing conditions are not particularly limited, and are preferably about 150 to 280° C. (more preferably about 170 to 240° C.) and preferably about 0.5 to 20 MPa (more preferably about 1 to 8 MPa).

[0108] [Printed wiring board] The printed wiring board of the present invention has a circuit pattern on the copper foil surface of the copper-clad laminate of the present invention. The patterning means for forming a circuit pattern on the copper foil surface of the copper-clad laminate include a subtractive method and a semi-additive method. As the semi-additive method, a method in which the copper foil surface of the copper-clad laminate is patterned with a resist film, electrolytic copper plating is performed, the resist is removed, and etching is performed with an alkaline solution is exemplified. In addition, the thickness of the circuit pattern layer in the printed wiring board is not particularly limited. In addition, a multilayer board can be obtained by laminating the same printed wiring board or other known printed wiring boards or printed circuit boards on the printed wiring board as a core. When laminating, the adhesive composition and other known adhesive compositions other than the adhesive composition can be used in combination. In addition, the number of layers in the multilayer board is not particularly limited. In addition, a via hole may be inserted and the inside may be plated each time lamination is performed. The line / space ratio of the circuit pattern is not particularly limited, but is preferably about 1 μm / 1 μm to 100 μm / 100 μm. The height of the circuit pattern is not particularly limited, but is preferably about 1 to 50 μm.

[0109] [Polyimide film] The polyimide film of the present invention is a cured product of the polyimide resin composition of the present invention.

[0110] The method for producing the polyimide film of the present invention includes coating the polyimide resin composition on the aforementioned support, curing the composition by heating to form a polyimide resin layer, and peeling the support from the polyimide resin layer.

[0111] The method for coating the polyimide resin composition on the support is not particularly limited, and includes the above-mentioned coating means. The heat treatment conditions are also not particularly limited, and examples thereof include a method of heating at a temperature of about 100 to 180° C. for about 0.5 to 3 hours.

[0112] The thickness of the polyimide resin layer after heat treatment is not particularly limited, but the thickness after drying is preferably about 1 to 50 μm.

[0113] The polyimide resin composition used in the polyimide film of the present invention may contain various additives as long as they do not impair the effects of the present invention, such as a dehydrating agent, a plasticizer, a weathering agent, an antioxidant, a heat stabilizer, a lubricant, an antistatic agent, a brightening agent, a colorant, a conductive agent, a release agent, a surface treatment agent, a viscosity adjuster, an inorganic filler, an inorganic pigment, and an organic pigment.

[0114] Examples of inorganic fillers include silica fillers, phosphorus-based fillers, fluorine-based fillers, and inorganic ion exchanger fillers. The silica filler may be one whose surface has been modified with a treatment agent such as a silane coupling agent. Commercially available inorganic fillers include "FB-3SDC" and "SFP-20M" manufactured by Denka Co., Ltd., "SC-2500-SPJ", "SC-2500-SXJ", and "SC-2500-SVJ" manufactured by Admatechs Co., Ltd., "Exolit OP935" manufactured by Clariant Chemicals Co., Ltd., "KTL-500F" manufactured by Kitamura Co., Ltd., and IXE manufactured by Toagosei Co., Ltd.

[0115] Examples of inorganic pigments include cadmium red, cadmium lemon yellow, cadmium yellow orange, titanium dioxide, carbon black, black iron oxide, and black complex inorganic pigments.

[0116] Examples of organic pigments include aniline black, perylene black, anthraquinone black, benzidine-based yellow pigments, phthalocyanine blue, and phthalocyanine green.

[0117] The content of the additive in the polyimide resin composition of the present invention is not particularly limited, but is preferably 1 to 150 parts by mass per 100 parts by mass of the component (A) (calculated as non-volatile content). EXAMPLES

[0118] The present invention will be described in detail below with reference to examples, but is not limited thereto. Unless otherwise specified, all "%" is by mass.

[0119] Example 1 In a reaction vessel equipped with a stirrer, a water divider, a thermometer and a nitrogen gas inlet tube, 200.0 g of 4,4'-[propane-2,2-diylbis(1,4-phenyleneoxy)]diphthalic dianhydride (trade name "BisDA-1000", manufactured by SABIC Innovative Plastics Japan, LLC. hereinafter abbreviated as BisDA), 619.0 g of diethyl carbonate, 132.6 g of 1,2-dimethoxyethane and 132.6 g of methylcyclohexane were charged and heated to 75°C. Next, 197.8 g of dimer diamine (trade name "PRIAMINE1075", manufactured by Croda Japan, hereinafter referred to as PRIAMINE1075) was gradually added, and the mixture was heated to 115°C and subjected to an imidization reaction for 10 hours to obtain a polyimide solution (non-volatile content 30%). The obtained solution was used as a polyimide resin composition. (The same applies below)

[0120] Examples 2 to 18, Comparative Example 1 The same procedure as in Example 1 was carried out except that the compositions and amounts used were changed to those shown in Table 1, and polyimide resins with a non-volatile content of 30% were obtained.

[0121] Comparative Examples 2 and 3 The same procedure as in Example 1 was carried out except that the type of solvent was changed to one shown in Table 1, but the produced polyamic acid did not dissolve, and polyimide could not be obtained.

[0122] <Preparation of evaluation samples> The polyimide resin compositions of Examples 1 to 18 and Comparative Example 1 were applied to a release paper (manufactured by San-A Chemical Industries, Ltd.), dried at 150°C for 5 minutes and then at 170°C for 30 minutes, and then the release paper was peeled off to obtain a polyimide film having a thickness of 25 μm. Two sheets of the film were laminated and melted by a heat press at 120°C to prepare an evaluation sample.

[0123] <Dielectric constant and dielectric loss tangent> Using a network analyzer (Keysight Technologies, device name: "P5003A") and a split post dielectric resonator (QWED) with a measurement frequency of 10.124 GHz, the resonant frequency and peak Q value of the resonator alone with nothing inserted were measured. Next, the evaluation sample was cut into 4 cm x 5 cm pieces to prepare test pieces, and then multiple test pieces were stacked together so that the total thickness was 100 μm or more and inserted into a resonator. The resonance frequency and Q value were then measured when the test pieces were inserted. The dielectric constant (Dk) was calculated from the difference in resonance frequency between the resonator alone and when the test piece was inserted, and the dielectric loss tangent (Df) was calculated from the difference in Q value and the difference in resonance frequency between the resonator alone and when the test piece was inserted. The results are shown in Table 1.

[0124] [Table 1]

[0125] The abbreviations in Table 1 are as follows: <Aromatic tetracarboxylic acid anhydride> Component (a1) BisDA: 4,4'-[propane-2,2-diylbis(1,4-phenyleneoxy)]diphthalic dianhydride, product name: "BisDA-1000", manufactured by SABIC Innovative Plastics Japan, LLC 6FDA: 2,2-bis(3,4-dicarboxyphenyl)hexafluoropropane dianhydride, manufactured by Daikin Co., Ltd. <Diamine> (a2) Component DDA: Dimer diamine, product name: "PRIAMINE1075", manufactured by Croda Japan Co., Ltd. ODA: 4,4'-diaminophenyl ether, manufactured by Wakayama Seika Kogyo Co., Ltd. <Organic solvent> (B1) Component DEC: Diethyl carbonate (boiling point: 126°C) ·AcOBu: n-Butyl acetate (boiling point: 126°C) (B2) Component DMG: 1,2-dimethoxyethane (boiling point: 82°C) MEK: Methyl ethyl ketone (boiling point: 80°C) ·MIBK: Methyl isobutyl ketone (boiling point: 116°C) MCH: Methylcyclohexane (boiling point: 101°C) ·OCT: n-octane (boiling point: 126℃) C-800: 2-methylheptane (boiling point: 116°C, product name: Kyowasol C-800, manufactured by KH Neochem Co., Ltd.) (Other solvents) ·DMAc: N,N-Dimethylacetamide (boiling point: 165℃)

[0126] <Preparation of Adhesive Composition> Evaluation example 1 The polyimide resin composition of Example 1 (100.0 g, non-volatile content: 30.0 g), a polyfunctional epoxy resin (trade name: "TETRAD-X", manufactured by Mitsubishi Gas Chemical Co., Inc.) (0.78 g, non-volatile content: 0.78 g) as a crosslinking agent, an active ester resin (trade name: "EPICLON HPC-8000-65T", manufactured by DIC Corporation) (2.67 g, non-volatile content: 1.75 g) and an imidazole-based epoxy resin (trade name: "Curesol" An adhesive composition with a nonvolatile content of 33% was obtained by mixing and thoroughly stirring 0.008 g of "2E4MZ-A", manufactured by Shikoku Chemical Industries Co., Ltd.) (nonvolatile content 0.008 g), 32.5 g of silica (product name: "SC-2500-SPJ", manufactured by Admatechs Co., Ltd.) as an inorganic filler (nonvolatile content 32.5 g), and 62.1 g of cyclopentanone as an organic solvent.

[0127] Evaluation examples 2 to 4, comparative evaluation example 1 The same procedure as in Evaluation Example 1 was carried out using each of the polyimide resin compositions shown in Table 2, to obtain adhesive compositions each having a non-volatile content of 33%.

[0128] <Preparation of adhesive sheet> The obtained adhesive composition was applied to a release paper (manufactured by San-A Chemical Co., Ltd.) using a gap coater so that the thickness after drying would be 25 μm, and then dried at 150° C. for 5 minutes to obtain an adhesive sheet (release paper / adhesive layer).

[0129] <Measurement of relative permittivity and dielectric loss tangent> The release paper was peeled off from the adhesive sheet (release paper / adhesive layer), the adhesive layer was placed on a press support, and the adhesive layer was cured by heating and pressing for 90 minutes at a pressure of 5 MPa and 180°C via the same press support on the side of the adhesive layer, to produce a thermally cured adhesive sheet (support / adhesive layer / support). The press support was removed from the adhesive sheet, and the relative dielectric constant (Dk) and dielectric loss tangent (Df) of the adhesive layer were calculated using the same method as in the previous paragraph. The results are shown in Table 2.

[0130] <Preparation of copper-clad laminate> The release paper was peeled off from the adhesive sheet (release paper / adhesive layer), and the sheet was placed on the mirror side of a commercially available electrolytic copper foil (product name "F2-WS", manufactured by Furukawa Electric Co., Ltd.) (film thickness 18 μm), and the other side was placed on a commercially available polyimide film (product name "Kapton 100EN", manufactured by Toray-DuPont Co., Ltd.; film thickness 25 μm; thermal expansion coefficient; 15 ppm / °C) to produce a polyimide film-adhesive layer-electrolytic copper foil laminate. The sheet was then placed on a press support, and cured from above with a support made of the same material at a pressure of 5 MPa and a temperature of 180°C for 90 minutes in a hot press to produce a copper-clad laminate.

[0131] <Adhesion test> The peel strength (N / mm) of the copper-clad laminate was measured in accordance with JIS C 6481 (Test method for copper-clad laminate for flexible printed wiring boards). The results are shown in Table 2.

[0132] <Solder heat resistance test> The copper-clad laminate was left in a thermostatic chamber at 23°C and 50% humidity for 24 hours, and then floated, copper foil side down, in a solder bath at 288°C to check for the presence or absence of bubbles and evaluate according to the following criteria. The results are shown in Table 2. (Evaluation Criteria) ○: No change in appearance ×: Foaming and swelling

[0133] [Table 2]

Claims

1. A polyimide resin composition comprising: a polyimide (A) which is a reaction product of a monomer group including an aromatic tetracarboxylic anhydride (a1) and a diamine (a2) including a dimer diamine; and two or more different organic solvents (B), The component (B) does not contain an organic solvent containing a nitrogen atom, The component (B) contains an ester (B1) and at least one organic solvent (B2) selected from the group consisting of ketones, ethers, aliphatic hydrocarbons, and alicyclic hydrocarbons, A polyimide resin composition, wherein the boiling point of the component (B1) is 60°C or higher and 150°C or lower, and the boiling point of the component (B2) is 60°C or higher and 150°C or lower.

2. The polyimide resin composition according to claim 1, wherein the component (a2) further comprises an alicyclic diamine and / or an aromatic diamine.

3. 3. The polyimide resin composition according to claim 1, wherein the content ratio of the component (B1) and the component (B2) is, in mass ratio, (B1) / (B2)=10 / 90 to 90 / 10.

4. 4. The polyimide resin composition according to claim 1, wherein the component (B) does not contain an aromatic hydrocarbon.

5. 5. The polyimide resin composition according to claim 1, wherein the component (B1) is an aliphatic ester.

6. An adhesive composition comprising the polyimide resin composition according to any one of claims 1 to 5 and a crosslinking agent.

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