Polyamic acid, polyimide, metal-clad laminates, and circuit boards

Abstract

To provide a polyimide excellent in heat dissipation property (thermal conductivity), resilience and toughness, and heat resistance.SOLUTION: A polyamide acid and a polyimide include: an acid anhydride residue derived from an acid anhydride constituent of formula (1); and a diamine residue derived from a diamine constituent, where there are included 50 mol% or more of an acid anhydride residue derived from formula (1) to total acid anhydride residues, and 50 mol% or more of a diamine residue derived from a benzanilide derivative to total diamine residues.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to polyamic acid, polyimide obtained by imidizing the polyamic acid, and metal-clad laminates and circuit boards using a layer of the polyimide. [Background technology]

[0002] In recent years, with the miniaturization, weight reduction, and space-saving of electronic devices, the demand for flexible printed circuit boards (FPCs) has increased. These FPCs are thin, lightweight, flexible, and possess excellent durability even after repeated bending. Because FPCs enable three-dimensional and high-density mounting even in limited spaces, their applications are expanding to include wiring in the moving parts of electronic devices such as HDDs, DVDs, and smartphones, as well as components such as cables and connectors. Most FPCs are manufactured by forming circuits on the metal layer of a metal-clad laminate, which consists of a metal layer using metal foil and an insulating resin substrate (insulating resin layer).

[0003] Furthermore, with the recent miniaturization of electronic devices and the increase in information processing load, the integration density of circuits has increased, leading to an expected increase in heat generated from mounted components. Moreover, in order to achieve faster information processing and improved reliability, it is necessary to enhance the heat dissipation characteristics of the heat generated within the device. Conventionally, methods such as installing thick aluminum plates with high thermal conductivity or cooling fans have been used to improve heat dissipation within the device, but due to the demand for miniaturization of devices, it is sometimes not possible to install such equipment.

[0004] Furthermore, to improve heat dissipation, it is considered effective to increase the thermal conductivity of the electronic device itself. For example, a technique of incorporating a thermally conductive filler into the insulating resin layer that makes up the wiring board is being investigated. More specifically, it is being investigated to disperse highly thermally conductive fillers such as aluminum oxide, boron nitride, aluminum nitride, and silicon nitride into the resin that forms the insulating resin layer. For example, a technique of incorporating a thermally conductive filler into highly heat-resistant polyimide has been reported (for example, Patent Documents 1 to 7). In addition, it is also being considered to improve heat dissipation in the thickness direction by making the electronic device (insulating resin layer) itself thinner. [Prior art documents] [Patent Documents]

[0005] [Patent Document 1] Patent No. 5235211 [Patent Document 2] Patent No. 5442491 [Patent Document 3] Patent No. 5297740 [Patent Document 4] Patent No. 5665449 [Patent Document 5] Patent No. 5330396 [Patent Document 6] Patent No. 5665846 [Patent Document 7] Patent No. 5650084 [Overview of the Initiative] [Problems that the invention aims to solve]

[0006] However, increasing the filling ratio of thermal conductive fillers in the resin tends to reduce the relative resin content, leading to a decrease in the flexibility and toughness of the cured resin product. This may cause the film to tear during FPC processing after the circuit pattern has been formed. This is expected to become even more pronounced when the insulating resin layer is thin.

[0007] On the other hand, when a resin component with relatively good flexibility and toughness is used in the insulating resin layer, there is a tendency for heat resistance to decrease.

[0008] Thus, although there is a demand for improved heat dissipation within electronic devices, conventional technology has room for improvement in satisfying all requirements for heat dissipation (thermal conductivity), flexibility, toughness, and heat resistance of the insulating resin layer that constitutes the wiring board.

[0009] Therefore, after diligent research by the inventors of this application, they discovered that when using a polyimide layer as an insulating resin layer constituting a wiring board, it is effective to use specific compounds as the acid anhydride component and the diamine component constituting the polyimide, and to adjust their content to a predetermined range, thereby completing the present invention.

[0010] Therefore, the object of the present invention is to provide a polyamic acid that provides a polyimide layer with excellent heat dissipation (thermal conductivity), flexibility, toughness, and heat resistance. Another object of the present invention is to provide a metal-clad laminate and a circuit board comprising an insulating resin layer having a polyimide layer. [Means for solving the problem]

[0011] In other words, the present invention is as follows: [1] Acid anhydride residues derived from the acid anhydride component represented by the following general formula (1), Diamine residues derived from the diamine component represented by general formula (2) and It contains, The total acid anhydride residues contain 50 mol% or more of acid anhydride residues derived from the acid anhydride component represented by the following general formula (1), A polyamic acid characterized by containing 50 mol% or more of diamine residues derived from a diamine component represented by the following general formula (2), relative to the total number of diamine residues. [ka] [Chemical formula] [In formula (2), each R independently represents a halogen atom, an alkyl group or an alkoxy group having 1 to 6 carbon atoms which may be substituted with a halogen atom, or a phenyl group or a phenoxy group which may be substituted with a monovalent hydrocarbon group or an alkoxy group having 1 to 6 carbon atoms. m and n each independently represent the number of substituents, m represents an integer of 0 to 4, and n represents an integer of 0 to 4.] [2] The polyamic acid according to [1], characterized by containing 10 mol% to 50 mol% of a diamine residue derived from a diamine component represented by the following general formula (3). [Chemical formula] [In formula (3), Z represents -O-. Each R independently represents a halogen atom, an alkyl group or an alkoxy group having 1 to 6 carbon atoms which may be substituted with a halogen atom, or a phenyl group or a phenoxy group which may be substituted with a monovalent hydrocarbon group or an alkoxy group having 1 to 6 carbon atoms. n1 represents the number of substituents and is an integer of 0 to 4. n2 represents an integer of 0 to 3.] [3] A polyimide obtained by imidizing the polyamic acid according to [1] or [2]. [4] The following a) and b); a) The end crack resistance measured at a width of 20 mm is within the range of 30 N or more and 500 N or less, b) The thermal conductivity (λz) in the thickness direction is within the range of 0.20 W / m·K or more, The polyimide according to [3], which satisfies the above conditions. [5] Further, the following condition c); c) The thermal diffusivity (α) in the thickness direction is within the range of 0.100 m , , 2 , , , , , / s or more, The polyimide according to [4], which satisfies the above conditions. [6] Further, the following condition d); d) The glass transition temperature is 250 °C or more, The polyimide according to [4] or [5], which satisfies the above conditions. [7] Further, the following condition e); e) The tear propagation resistance is 1.5 kN / m. A polyimide according to any one of [4] to [6], characterized in that it satisfies the following conditions. [8] Furthermore, the following condition f); f) The coefficient of thermal expansion is 50 ppm / K or less. A polyimide according to any one of [4] to [7], characterized in that it satisfies the following conditions. [9] A metal-clad laminate comprising an insulating resin layer consisting of one or more layers, and a metal layer laminated on one or both sides of the insulating resin layer, A metal-clad laminate characterized in that at least one of the insulating resin layers is composed of a polyimide layer according to any one of [3] to [8].

[10] A circuit board comprising an insulating resin layer consisting of one or more layers, and a conductive circuit layer laminated on one or both sides of the insulating resin layer, A circuit board in which at least one of the insulating resin layers is composed of a polyimide layer as described in any one of [3] to [8]. [Effects of the Invention]

[0012] According to the present invention, a polyimide with excellent heat dissipation (thermal conductivity), flexibility, toughness, and heat resistance can be obtained. [Modes for carrying out the invention]

[0013] Embodiments of the present invention will be described below.

[0014] <Polyamic acid, polyimide> The polyamic acid of the present invention is a precursor of polyimide and is composed of a tetravalent acid anhydride residue derived from a tetracarboxylic dianhydride (hereinafter sometimes simply referred to as "acid anhydride") component and a divalent diamine residue derived from a diamine compound (hereinafter sometimes simply referred to as "diamine") component. When these components are linked together and considered as a single repeating unit, the polyamic acid is composed of polymers of this repeating unit. The composition can be controlled by adjusting the amount (molar ratio) of the acid anhydride component and the diamine component.

[0015] For example, polyamic acids are typically obtained by dissolving a predetermined acid anhydride component and a diamine component in approximately equimolar amounts in an organic solvent and carrying out a polymerization reaction by stirring at a temperature usually in the range of 0 to 100°C for 30 minutes to 24 hours. In the reaction, the reactants are dissolved in the organic solvent so that the resulting precursor is in the range of 5 to 30% by weight, preferably in the range of 10 to 20% by weight. Examples of organic solvents used in the polymerization reaction include N,N-dimethylformamide, N,N-dimethylacetamide (DMAC), N-methyl-2-pyrrolidone, 2-butanone, dimethyl sulfoxide, dimethyl sulfate, cyclohexanone, dioxane, tetrahydrofuran, diglyme, triglyme, and γ-ptylolactone. Two or more of these solvents can be used in combination, and furthermore, aromatic hydrocarbons such as xylene and toluene can also be used in combination.

[0016] In the synthesis of polyamic acids and polyimides, the acid anhydride component and the diamine component may be used individually or in combination of two or more. By selecting the types of acid anhydride and diamine components, and the molar ratio of each when two or more acid anhydrides or diamines are used, physical properties such as thermal conductivity, thermal expansion, adhesion, glass transition temperature, tear propagation resistance, edge crack resistance, and tensile elongation can be controlled.

[0017] Furthermore, the polyamic acid and polyimide of the present invention may be used with an end-cap encapsulant. Monoamines or dicarboxylic acids are preferred as end-cap encapsulants. The amount of end-cap encapsulant introduced is preferably in the range of 0.0001 moles to 0.1 moles per mole of acid anhydride component, and particularly preferably in the range of 0.001 moles to 0.05 moles. Recommended monoamine end-cap encapsulants include, for example, methylamine, ethylamine, propylamine, butylamine, benzylamine, 4-methylbenzylamine, 4-ethylbenzylamine, 4-dodecylbenzylamine, 3-methylbenzylamine, aniline, and 4-methylaniline. Of these, benzylamine and aniline can be suitably used. Dicarboxylic acid end-cap encapsulants are preferred, and some of them may be cyclized. For example, phthalic acid, phthalic anhydride, 4-chlorophthalic acid, tetrafluorophthalic acid, cyclopentane-1,2-dicarboxylic acid, and 4-cyclohexene-1,2-dicarboxylic acid are recommended. Of these, phthalic acid and phthalic anhydride can be preferably used.

[0018] The synthesized polyamic acid is usually advantageous to use as a reaction solvent solution, but it can be concentrated, diluted, or replaced with other organic solvents as needed. Furthermore, polyamic acid is advantageous to use because it generally has excellent solvent solubility. The method for imidizing the polyamic acid is not particularly limited; for example, a heat treatment such as heating in the aforementioned solvent at a temperature range of 80°C to 400°C for 1 to 24 hours is preferably employed.

[0019] Furthermore, while there are no restrictions on the polyamic acid, it is preferable to adjust the viscosity to be in the range of 1,000 to 200,000 cP by adjusting the concentration and weight-average molecular weight (Mw). If the viscosity is too high, it can be diluted by adding a solvent. The weight-average molecular weight (Mw) of the polyamic acid is preferably in the range of 10,000 to 500,000, and more preferably in the range of 50,000 to 500,000. If the weight-average molecular weight is less than 10,000, the strength of the film tends to decrease and it becomes prone to embrittlement. On the other hand, if the weight-average molecular weight exceeds 500,000, the viscosity increases excessively, and defects such as uneven film thickness and streaks tend to occur during the coating process.

[0020] (Acid anhydride component) Herein, the acid anhydride component used in the polyamic acid and polyimide of the present invention is an acid anhydride represented by the following general formula (1). [ka]

[0021] The acid anhydride represented by formula (1) has a rigid structure in which aromatic rings are directly bonded (single bonds), and because it has a biphenyl structure, it is possible to impart high heat resistance and high thermal conductivity. Examples of this acid anhydride component include, but are not limited to, 3,3',4,4'-biphenyltetracarboxylic dianhydride (BPDA), 2,2',3,3'-biphenyltetracarboxylic dianhydride, and 2,3,3',4'-biphenyltetracarboxylic dianhydride. BPDA is preferred.

[0022] In the polyamic acid and polyimide of the present invention, the acid anhydride represented by formula (1) is contained in an amount of 50 mol% or more relative to 100 mol% of the total acid anhydride components. That is, the acid anhydride residues derived from this acid anhydride are 50 mol% or more relative to 100 mol% of the total acid anhydride residues of the synthesized polyamic acid and polyimide. If the acid anhydride component (acid anhydride residue) of formula (1) is less than 50 mol%, there is a risk that sufficient heat resistance and thermal conductivity cannot be obtained in the polyimide synthesized using it. Preferably, it is 75 mol% or more, more preferably 90 mol% or more, and even more preferably 100 mol%.

[0023] Furthermore, as acid anhydride components other than those mentioned above, known components used in the production of polyamic acids and polyimides can be used without limitation, but aromatic tetracarboxylic dianhydrides are preferred. In addition, anhydrides of tetracarboxylic acids having an aliphatic skeleton may be used, for example, aliphatic chain tetracarboxylic dianhydrides such as ethylenetetracarboxylic dianhydride and 1,2,3,4-butanetetracarboxylic dianhydride, or alicyclic tetracarboxylic dianhydrides may be used, for example, alicyclic tetracarboxylic dianhydrides such as 1,2,3,4-cyclobutanetetracarboxylic dianhydride, fluorenylidenebisphthalic anhydride, 1,2,4,5-cyclohexanetetracarboxylic dianhydride, and cyclopentanonebisspironorbornanetetracarboxylic dianhydride. Examples of aromatic tetracarboxylic dianhydrides include 3,3',4,4'-benzophenonetetracarboxylic dianhydride, 2,3',3,4'-benzophenonetetracarboxylic dianhydride, 2,2',3,3'-benzophenonetetracarboxylic dianhydride, 4,4'-(paraphenylenedicarbonyl)diphthalic anhydride, 4,4'-(metaphenylenedicarbonyl)diphthalic anhydride, pyromellitic dianhydride (PMDA), p-phenylenebis(trimellitate anhydride), 4,4'-oxydiphthalic dianhydride (ODPA), bis(2,3-dicarboxyphenyl)ether dianhydride, and 5,5'-bis(trifluoromethyl)-3,3',4 ,4'-tetracarboxydiphenyl ether dianhydride, bis{(trifluoromethyl)dicarboxyphenoxy}diphenyl ether dianhydride, bis{3,5-di(trifluoromethyl)phenoxy}pyromellitic acid dianhydride, bis{(trifluoromethyl)dicarboxyphenoxy}benzene dianhydride, bis{(trifluoromethyl)dicarboxyphenoxy}, bis(dicarboxyphenoxy)trifluoromethylbenzene dianhydride, bis(dicarboxyphenoxy)bis(trifluoromethyl)benzene dianhydride, bis(dicarboxyphenoxy)tetrakis(trifluoromethyl)benzene dianhydride, 2,2-bis{(4-(3,4-Dicarboxyphenoxy)phenyl}hexafluoropropane dianhydride, bis{(trifluoromethyl)dicarboxyphenoxy}biphenyl dianhydride, bis{(trifluoromethyl)dicarboxyphenoxy}bis(trifluoromethyl)biphenyl dianhydride, bis(dicarboxyphenoxy)bis(trifluoromethyl)biphenyl dianhydride, 2,2'-bis(3,4-dicarboxyphenyl)hexafluoropropane dianhydride, naphthalene-2,3,6,7-tetracarboxylic acid dianhydride, naphthalene-1,2,5,6-tetracarboxylic acid dianhydride , naphthalene-1,2,6,7-tetracarboxylic dianhydride, naphthalene-1,2,4,5-tetracarboxylic dianhydride, naphthalene-1,4,5,8-tetracarboxylic dianhydride, 2,6-dichloronaphthalene-1,4,5,8-tetracarboxylic dianhydride, 2,7-dichloronaphthalene-1,4,5,8-tetracarboxylic dianhydride, 2,3,6,7-tetrachloronaphthalene-1,4,5,8-tetracarboxylic dianhydride, 1,4,5,8-tetrachloronaphthalene-2,3,6,7-tetracarboxylic dianhydride, 3,3'',4,4''-p-tetracarboxylic dianhydride Phenyltetracarboxylic dianhydride, 2,2'',3,3''-p-terphenyltetracarboxylic dianhydride, 2,3,3'',4''-p-terphenyltetracarboxylic dianhydride, 2,2-bis(2,3-dicarboxyphenyl)-propane dianhydride, 2,2-bis(3,4-dicarboxyphenyl)-propane dianhydride, bis(2,3-dicarboxyphenyl)methane dianhydride, bis(3,4-dicarboxyphenyl)methane dianhydride, 1,1-bis(2,3-dicarboxyphenyl)ethane dianhydride, 1,1-bis(3,4-dicarboxyphenyl ) Ethane dianhydride, 3,3',4,4'-diphenylsulfonetetracarboxylic dianhydride, 2,2',3,3'-diphenylsulfonetetracarboxylic dianhydride, 2,3,3',4'-diphenylsulfonetetracarboxylic dianhydride, thiophene-2,3,4,5-tetracarboxylic dianhydride, perylene-2,3,8,9-tetracarboxylic dianhydride, perylene-3,4,9,10-tetracarboxylic dianhydride, perylene-4,5,10,11-tetracarboxylic dianhydride, perylene-5,6,11,12-tetracarboxylic dianhydride, phenanthrene-1,2,7,8-tetracarboxylic dianhydride, phenanthrene-1,2,6,7-tetracarboxylic dianhydride, phenanthrene-1,2,9,10-tetracarboxylic dianhydride, pyrazine-2,3,5,6-tetracarboxylic dianhydride, pyrrolidine-2,3,4,5-tetracarboxylic dianhydride, (trifluoromethyl)pyromellitic acid dianhydride, di(trifluoromethyl)pyromellitic acid dianhydride, di(heptafluoropropyl)pyromellitic acid dianhydride, pentafluoroethylpyromellitic acid Examples include acid dianhydrides, 2,2-bis(3,4-dicarboxyphenyl)hexafluoropropane dianhydride, 5,5'-bis(trifluoromethyl)-3,3',4,4'-tetracarboxybiphenyl dianhydride, 2,2',5,5'-tetrakis(trifluoromethyl)-3,3',4,4'-tetracarboxybiphenyl dianhydride, 5,5'-bis(trifluoromethyl)-3,3',4,4'-tetracarboxybenzophenone dianhydride, and trifluoromethylbenzene dianhydride.

[0024] (Diamine component) The diamine component used in the polyamic acid and polyimide of the present invention is an essential diamine represented by the following general formula (2). [ka] [In formula (2), R independently represents a halogen atom, a C1-C6 alkyl or alkoxy group which may be substituted with a halogen atom, or a C1-C6 monovalent hydrocarbon or alkoxy group which may be substituted with a C1-C6 phenyl or phenoxy group. m and n independently represent the number of substitutions, where m is an integer from 0 to 4 and n is an integer from 0 to 4. Note that m=0 or n=0 means that there is no R (unsubstituted, no side chain).]

[0025] The diamine represented by formula (2) has a rigid structure in which aromatic rings are linked by amide bonds, and because it brings about intermolecular interactions (such as hydrogen bonding) between oxygen atoms (O) and hydrogen atoms (H), it is possible to impart high heat resistance and high thermal conductivity. Examples of this diamine component include 4,4'-diaminobenzanilide (DABA), 4,4'-diamino-2'-methoxybenzanilide (MABA), 3,5-diamino-3'-trifluoromethylbenzanilide, and 3,5-diamino-4'-trifluoromethylbenzanilide. DABA is preferred due to its high heat resistance and high thermal conductivity.

[0026] In the polyamic acid and polyimide of the present invention, the diamine represented by formula (2) is contained in an amount of 50 mol% or more relative to 100 mol% of the total diamine components. That is, the diamine residues derived from this diamine are 50 mol% or more relative to 100 mol% of the total diamine residues of the synthesized polyamic acid and polyimide. If the diamine component (diamine residue) of formula (2) is less than 50 mol%, there is a risk that sufficient heat resistance and thermal conductivity cannot be obtained in the polyimide synthesized using it. For heat resistance and thermal conductivity, it is preferably 75 mol% or more, more preferably 90 mol% or more, and even more preferably 100 mol%.

[0027] Furthermore, in the polyamic acid and polyimide of the present invention, it is preferable to use a diamine component represented by the following general formula (3) in addition to the diamine component (diamine residue) of formula (2) above. [ka] [In formula (3), Z represents -O-. R independently represents a halogen atom, a C1-C6 alkyl or alkoxy group which may be substituted with a halogen atom, or a C1-C6 monovalent hydrocarbon or alkoxy group which may be substituted with a C1-C6 phenyl or phenoxy group. n1 represents the number of substitutions and is an integer from 0 to 4. n2 represents an integer from 0 to 3. Note that n1=0 or n2=0 means that there is no R (unsubstituted, no side chain).]

[0028] The aromatic diamine compound represented by formula (3) above has two or more aromatic rings and an ether bond, which is a divalent linking group Z. This increases the degree of freedom of the polyimide molecular chain synthesized using it, thereby imparting flexibility. This is thought to contribute to improving the flexibility of the polyimide molecular chain and promoting increased toughness. By using the diamine component (diamine residue) of formula (3) together with the diamine component (diamine residue) of formula (2), the effect of structural entanglement between the rigid molecular chain of formula (2) and the flexible molecular chain of formula (3) is created. Furthermore, it is presumed that the generation of intermolecular interactions (such as hydrogen bonding) between oxygen atoms (O) and hydrogen atoms (H) is also strengthened. This makes it possible to improve toughness (tear propagation resistance, edge crack resistance) while maintaining relatively high heat resistance and thermal conductivity, thus achieving both properties, which is preferable.

[0029] From the viewpoint of achieving both of the above-mentioned properties, the diamine component (diamine residue) represented by formula (3) is preferably contained in an amount of 10 to 50 mol% of the total diamine components (diamine residues) per 100 mol%, and more preferably 30 to 50 mol%, and even more preferably 40 to 50 mol%, in order to impart high toughness. The content of the diamine component (diamine residue) of formula (2) and the diamine component (diamine residue) of formula (3) can be appropriately changed, taking into consideration the balance of properties such as heat resistance, thermal conductivity, and toughness.

[0030] Examples of diamines represented by formula (3) include, but are not limited to, 4,4'-diaminodiphenyl ether, 3,4'-diaminodiphenyl ether, bis(p-β-amino-t-butylphenyl) ether, 1,3-bis(3-aminophenoxy)benzene (APB), 1,3-bis(4-aminophenoxy)benzene (TPE-R), 1,4-bis(3-aminophenoxy)benzene or 1,4-bis(4-aminophenoxy)benzene, and bis[4-(4-aminophenoxy)phenyl] ether.

[0031] Other than those listed above, known diamine components used in the production of polyamic acids and polyimides can be used without limitation, but aromatic diamine compounds are preferred. Diamine compounds having an aliphatic skeleton can also be used. For example, 3,4'-diaminodiphenylmethane, 3,4'-diaminodiphenylpropane, 3,4'-diaminodiphenyl sulfide, 3,4'-diaminobenzophenone, (3,3'-bisamino)diphenylamine, 3-[4-(4-aminophenoxy)phenoxy]benzeneamine, 3-[3-(4-aminophenoxy)phenoxy]benzeneamine, 4,4'-[2-methyl-(1,3-phenylene)bisoxy]bisaniline, 4,4'-[4-methyl-( 1,3-phenylene)bisoxy]bisaniline, 4,4'-[5-methyl-(1,3-phenylene)bisoxy]bisaniline, bis[4-(3-aminophenoxy)phenyl]methane, bis[4-(3-aminophenoxy)phenyl]propane, bis[4-(3-aminophenoxy)phenyl]ether, bis[4-(3-aminophenoxy)phenyl]sulfone, bis[4-(3-aminophenoxy)]benzophenone, bis[4,4'-(3-aminophenoxy )]benzanilide, 4-[3-[4-(4-aminophenoxy)phenoxy]phenoxy]aniline, 4,4'-[oxybis(3,1-phenyleneoxy)]bisaniline, bis[4-(4-aminophenoxy)phenyl]ketone (BAPK), bis[4-(3-aminophenoxy)]biphenyl, bis[4-(4-aminophenoxy)]biphenyl, 2,2-bis(4-aminophenoxyphenyl)propane (BAPP), 2,2'-bis(trifluoromethyl) -4,4'-diaminobiphenyl (TFMB), bis[4-(aminophenoxy)phenyl]sulfone (BAPS), 4,6-dimethyl-m-phenylenediamine, 2,5-dimethyl-p-phenylenediamine, 2,4-diaminomesitylene, 3,3'-dimethyl-4,4'-diaminodiphenylmethane, 3,5,3',5'-tetramethyl-4,4'-diaminodiphenylmethane, 2,4-toluenediamine, m-phenylenediamine, p-phenylenediamine, 4,4'-diaminodiphenylpropane, 3,3'-diaminodiphenylpropane, 4,4'-diaminodiphenylethane, 3,3'-diaminodiphenylethane, 4,4'-diaminodiphenylmethane, 3,3'-diaminodiphenylmethane, 2,2-bis(4-aminophenoxyphenyl)propane, 2,2-bis[4-(4-aminophenoxy)phenyl]propane, 4,4'-diaminodiphenyl sulfide, 3,3'-diaminodiphenyl sulfide, 4,4'-diaminodiphenyl sulfone, 3,3'-diaminodiphenyl sulfone, 1,3-bis 3-aminophenoxy)benzene, 1,3-bis(4-aminophenoxy)benzene, 1,4-bis(4-aminophenoxy)benzene, benzidine, 3,3'-diaminobiphenyl, 3,3'-dimethyl-4,4'-diaminobiphenyl, 3,3'-dimethoxybenzidine, 4,4"-diamino-p-terphenyl, 3,3"-diamino-p-terphenyl, bis(p-aminocyclohexyl)methane, bis(p-β-methyl-δ-aminopentyl)benzene, p-bis(2-methyl-4-aminopentyl)benzene, p-bis(1,1-dimethyl- 5-aminopentyl)benzene, 1,5-diaminonaphthalene, 2,6-diaminonaphthalene, 2,4-bis(β-amino-t-butyl)toluene, 2,4-diaminotoluene, m-xylene-2,5-diamine, p-xylene-2,5-diamine, m-xylylenediamine, p-xylylenediamine, 2,6-diaminopyridine, 2,5-diaminopyridine, 2,5-diamino-1,3,4-oxadiazole, piperazine, 4-(1H,1H,11H-eicosafluoroundecanoxy)-1,3-diaminobenzene, 4-(1H,1H-perfluoro -1-butanoxy)-1,3-diaminobenzene, 4-(1H,1H-perfluoro-1-heptanoxy)-1,3-diaminobenzene, 4-(1H,1H-perfluoro-1-octanoxy)-1,3-diaminobenzene, 4-pentafluorophenoxy-1,3-diaminobenzene, 4-(2,3,5,6-tetrafluorophenoxy)-1,3-diaminobenzene, 4-(4-fluorophenoxy)-1,3-diaminobenzene, 4-(1H,1H,2H,2H-perfluoro-1-hexanoxy)-1,3-diaminobenzene, 4-(1H,1H,2H,2H-perfluoro-1-dodecanoxy)-1,3-diaminobenzene, (2,5)-diaminobenzotrifluoride, diaminotetra(trifluoromethyl)benzene, diamino(pentafluoroethyl)benzene, 2,5-diamino(perfluorohexyl)benzene, 2,5-diamino(perfluorobutyl)benzene, 2,2'-bis(trifluoromethyl)-4,4'-diaminobiphenyl, 3,3'-bis(trifluoromethyl)-4,4'-diaminobiphenyl, octafluorobenzidine, 4,4'-diaminodiphenyl ether , 2,2-bis(4-aminophenyl)hexafluoropropane, 1,3-bis(anilino)hexafluoropropane, 1,4-bis(anilino)octafluorobutane, 1,5-bis(anilino)decafluoropentane, 1,7-bis(anilino)tetradecafluoroheptane, 2,2'-bis(trifluoromethyl)-4,4'-diaminodiphenyl ether, 3,3'-bis(trifluoromethyl)-4,4'-diaminodiphenyl ether, 3,3',5,5'-tetrakis(trifluoromethyl)-4,4'-diaminodiphenyl ether, 3, 3'-Bis(trifluoromethyl)-4,4'-diaminobenzophenone, 4,4'-diamino-p-terphenyl, 1,4-bis(p-aminophenyl)benzene, p-(4-amino-2-trifluoromethylphenoxy)benzene, bis(aminophenoxy)bis(trifluoromethyl)benzene, bis(aminophenoxy)tetrakis(trifluoromethyl)benzene, 2,2-bis{4-(4-aminophenoxy)phenyl}hexafluoropropane, 2,2-bis{4-(3-aminophenoxy)phenyl}hexafluoropropane, 2,2-bis 4-(2-aminophenoxy)phenyl}hexafluoropropane, 2,2-bis{4-(4-aminophenoxy)-3,5-dimethylphenyl}hexafluoropropane, 2,2-bis{4-(4-aminophenoxy)-3,5-ditrifluoromethylphenyl}hexafluoropropane, 4,4'-bis(4-amino-2-trifluoromethylphenoxy)biphenyl, 4,4'-bis(4-amino-3-trifluoromethylphenoxy)biphenyl, 4,4'-bis(4-amino-2-trifluoromethylphenoxy)diphenylsulfone, 4,Examples include aromatic diamines derived from 4'-bis(3-amino-5-trifluoromethylphenoxy)diphenylsulfone, 2,2-bis{4-(4-amino-3-trifluoromethylphenoxy)phenyl}hexafluoropropane, bis{(trifluoromethyl)aminophenoxy}biphenyl, bis[{(trifluoromethyl)aminophenoxy}phenyl]hexafluoropropane, bis{2-[(aminophenoxy)phenyl]hexafluoroisopropyl}benzene, and 4,4'-bis(4-aminophenoxy)octafluorobiphenyl. Also, examples include aliphatic diamines such as dimer amines, hexamethylenediamine, and pentamethylenediamine.

[0032] (Other ingredients) The polyamic acids and polyimides of the present invention may optionally contain fillers and other components such as silicon dioxide, aluminum oxide, boron nitride, magnesium oxide, beryllium oxide, aluminum nitride, silicon nitride, aluminum fluoride, calcium fluoride, and metal salts of organophosphinic acids, provided that they do not hinder the objectives of the present invention. These components can be used individually or in combination of two or more.

[0033] (Method for forming a polyimide layer) Methods for forming polyimide layers include, for example, [1] a method of producing a resin film by applying and drying a polyamic acid solution to a support substrate (e.g., a metal layer), followed by imidation (hereinafter referred to as the casting method), and [2] a method of producing a resin film by applying and drying a polyamic acid solution to a support substrate, peeling off the polyamic acid gel film from the support substrate, and then imidating it. Furthermore, when the polyimide consists of multiple layers, examples of manufacturing methods include, for example, [3] a method of repeatedly applying and drying a polyamic acid solution to a support substrate, followed by imidation (hereinafter referred to as the sequential coating method), and [4] a method of simultaneously applying and drying a polyamic acid laminated structure to a support substrate by multilayer extrusion, followed by imidation (hereinafter referred to as the multilayer extrusion method). From the viewpoint of controlling dimensional stability and adhesion to the metal layer, it is preferable to form the polyimide layer (polyimide film, and the insulating resin layer and metal-clad laminate described later using the same) by the casting method or sequential coating method.

[0034] The method for applying the polyamic acid solution (or polyimide solution) onto the substrate is not particularly limited, and it can be applied using a coater such as a comma, die, knife, or lip. When forming a multilayer polyimide layer, it is preferable to repeat the operation of applying the polyamic acid solution (or polyimide solution) to the substrate and drying it. The insulating resin layer (described later) in the present invention may be formed from only a single layer of the above polyimide, or it may be formed from multiple layers of polyimide.

[0035] As described above, the polyimide (layer) of the present invention is excellent in heat dissipation (thermal conductivity), flexibility, toughness, and heat resistance. In particular, it is preferable that a) edge tear resistance and b) thermal conductivity in the thickness direction (λz) are simultaneously satisfied. Furthermore, it is preferable that one or more of the following properties are within a predetermined range: c) thermal diffusivity in the thickness direction (α), d) glass transition temperature (Tg), e) tear propagation resistance, and f) coefficient of thermal expansion.

[0036] The polyimide (layer) of the present invention preferably has an edge tear resistance measured at a width of 20 mm (according to JIS standards) in the range of 0.30 N to 500 N. A more preferable lower limit is 60 N or higher, an even more preferable lower limit is 75 N or higher, and an even more preferable lower limit is 100 N or higher. On the other hand, there is no particular limitation on the preferred upper limit. Having this range helps prevent problems such as tearing during processing and use.

[0037] The polyimide (layer) of the present invention preferably has a thermal conductivity (λz) in the thickness direction of 0.20 W / m·K or higher. More preferably, it is 0.22 W / m·K or higher. If the thermal conductivity λz is less than 0.20 W / m·K, the resin alone may not be able to sufficiently dissipate heat when applied to heat dissipation applications, resulting in a weak heat dissipation effect and potentially failing to achieve the intended purpose.

[0038] Furthermore, the polyimide (layer) of the present invention has a thermal diffusivity (α) in the thickness direction of 0.100 m 2 It is preferable that the thermal diffusivity (α) is 0.100 m. 2 If the value is less than / s, the resin alone may not be able to adequately dissipate heat when applied for heat dissipation purposes, resulting in a weak heat dissipation effect and potentially failing to achieve its intended purpose. Note that the thermal conductivity (λ z Since the thermal diffusivity (α) and thermal diffusivity are properties that do not depend on the thickness of the polyimide layer, the thickness conditions for measurement can be appropriately changed and set depending on the constraints and circumstances of the measuring equipment, etc.

[0039] Furthermore, the polyimide (layer) of the present invention preferably has a heat resistance of d) a glass transition temperature (Tg) of 250°C or higher. More preferably it is 270°C or higher, and even more preferably 3000°C or higher.

[0040] Furthermore, the polyimide (layer) of the present invention preferably has a tear propagation resistance of 1.5 kN / m or more. More preferably 3.0 kN / m or more, and more preferably 4.0 kN / m or more. The upper limit is not particularly limited. Having it within this range prevents problems such as tearing during processing and use.

[0041] Furthermore, the polyimide (layer) of the present invention preferably has a coefficient of thermal expansion (CTE) of 50 ppm / K or less, more preferably in the range of 1 ppm / K to 45 ppm / K.

[0042] Furthermore, in thermal decomposition tests, the polyimide (layer) of the present invention preferably has a 1% weight loss temperature (Td1) of 450°C or higher, more preferably 470°C or higher, and even more preferably 490°C or higher. By controlling it within this range, it has sufficient heat resistance even when applied to the main components of FPCs.

[0043] The polyimide (layer) of the present invention preferably has a thickness of, for example, 2 to 100 μm for the entire insulating resin layer / resin film, and more preferably in the range of 4 to 50 μm. If the thickness is less than 2 μm, problems such as wrinkles forming in the metal foil are likely to occur during the transport process when manufacturing the metal-clad laminate. Conversely, if the thickness exceeds 100 μm, it tends to be disadvantageous in terms of the expression of high thermal conductivity and toughness and flexibility.

[0044] <Metal-clad laminate> (metal layer) The material of the metal layer is not particularly limited, but examples include copper, stainless steel, iron, nickel, beryllium, aluminum, zinc, indium, silver, gold, tin, zirconium, tantalum, titanium, lead, magnesium, manganese, and alloys thereof. Among these, metal elements such as copper, iron, or nickel, or indium tin oxide (ITO) are preferred, and copper (copper foil) is more preferred. As for the copper foil, either electrolytic copper foil or rolled copper foil can be used. When selecting these metal layers, the properties required for the intended use, such as the conductivity of the metal layer, the light transmittance of the polyimide layer, and the adhesion to the polyimide layer, should be selected accordingly. There are no particular restrictions on the shape of the metal layer, but it may be processed as appropriate depending on the application. A roll-shaped form formed into a long length is preferably used.

[0045] The thickness of the metal layer is not particularly limited, but is preferably 100 μm or less, more preferably in the range of 0.1 to 70 μm, and even more preferably in the range of 1 to 50 μm. For heat dissipation applications, such as in automotive applications, large currents are often passed through, so a thicker metal layer (e.g., copper foil) is preferred to withstand the large currents. On the other hand, if the metal layer is too thick, the flexibility and processability of the laminated substrate tend to decrease, and the weight tends to increase.

[0046] (Insulating resin layer) The metal-clad laminate of the present invention comprises an insulating resin layer consisting of one or more layers, and a metal layer laminated on one side (single surface) or both sides (double surface) of the insulating resin layer, wherein at least one layer of the insulating resin layer is composed of the polyimide layer described above.

[0047] If the insulating resin layer consists of multiple polyimide layers, it may be a two-layer structure consisting of a polyimide layer (P1) directly laminated to the metal layer (described later) and a polyimide layer (P2) not directly laminated to the metal layer. There are no particular limitations, as illustrated in configurations 1 to 4 below, but it is preferably a three-layer structure, and more preferably the third polyimide layer (P3) is laminated in the order of (P1) / (P2) / (P3). M1 and M2 represent metal layers, and M1 and M2 may be the same or different. The polyimide layer (P1) directly laminated to the metal layer and the third polyimide layer (P3) may have the same composition. For example, when forming multiple polyimide layers by a casting method, a two-layer structure may be formed in which a polyimide layer (P1) directly laminated to the metal layer and a polyimide layer (P2) not directly laminated to the conductor layer are laminated in this order from the cast surface side, or a three-layer structure may be formed in which a polyimide layer (P1) directly laminated to the conductor layer, a polyimide layer (P2) not directly laminated to the conductor layer, and a third polyimide layer (P3) are laminated in this order from the cast surface side. The "cast surface" referred to here is the surface on the support side when forming the polyimide layer. The support may be the metal layer of the metal-clad laminate of the present invention (described later), glass, or a support when forming a gel film, etc. In the case of multiple polyimide layers, the surface opposite to the cast surface is described as the "laminate surface," but unless otherwise specified, the metal layer may or may not be laminated to the laminate surface.

[0048] Configuration 1;M1 / P1 / P2 Configuration 2; M1 / P1 / P2 / P1 (or P3) Configuration 3: M1 / P1 / P2 / P1 (or P3) / M2 (or M1) Configuration 4: M1 / P1 / P2 / P1 (or P3) / P2 / P1 (or P3) / M2 (or M1)

[0049] The polyimides constituting the polyimide layer (P1) and the polyimide layer (P3) are preferably thermoplastic polyimides, which improves the adhesion as an insulating resin layer and makes it suitable for application as an adhesive layer to a metal layer.

[0050] A preferred embodiment of the insulating resin layer comprises a thermoplastic polyimide layer (P1) and a non-thermoplastic polyimide layer (P2) composed of non-thermoplastic polyimide, wherein at least one side of the non-thermoplastic polyimide layer (P2) has a polyimide layer (P1) that becomes the thermoplastic polyimide layer. That is, the polyimide layer (P1) may be provided on one or both sides of the non-thermoplastic polyimide layer.

[0051] Furthermore, the non-thermoplastic polyimide layer constitutes a polyimide layer with low thermal expansion, and the thermoplastic polyimide layer constitutes a polyimide layer with high thermal expansion. Here, the low thermal expansion polyimide layer refers to a polyimide layer having a coefficient of thermal expansion (CTE) preferably in the range of 1 ppm / K to 25 ppm / K, more preferably in the range of 3 ppm / K to 25 ppm / K. The high thermal expansion polyimide layer refers to a polyimide layer having a CTE preferably in the range of 35 ppm / K or higher, more preferably in the range of 35 ppm / K to 80 ppm / K, and even more preferably in the range of 35 ppm / K to 70 ppm / K. The polyimide layer can be made to have a desired CTE by appropriately changing the combination of raw materials used, thickness, and drying / curing conditions.

[0052] The coefficient of thermal expansion (CTE) of the entire insulating resin layer is preferably within the range of 10 to 30 ppm / K. By controlling it within this range, deformation such as curling can be suppressed and high dimensional stability can be ensured. Here, CTE is the average value of the coefficients of thermal expansion of the insulating resin layer in the MD direction and TD direction.

[0053] Here, non-thermoplastic polyimide generally refers to polyimide that does not soften or become adhesive when heated, but in this invention, the storage modulus at 30°C measured using a dynamic viscoelasticity measuring device (DMA) is 1.0 × 10⁻⁶. 9The Pa is greater than or equal to 1.0 × 10⁻¹⁶, and the storage modulus at 350°C is 1.0 × 10⁻¹⁶. 9 This refers to polyimides with a storage modulus of Pa or higher. Furthermore, thermoplastic polyimides (also called "TPI") generally refer to polyimides whose glass transition temperature (Tg) can be clearly determined. In this embodiment, however, the storage modulus at 30°C measured using DMA is 1.0 × 10⁻⁶. 9 The Pa is greater than or equal to 1.0 × 10⁻¹⁶, and the storage modulus at 300°C is 1.0 × 10⁻¹⁶. 8 This refers to polyimides with a Pa rating of less than 1.5.

[0054] In the insulating resin layer, when the thickness of the polyimide layer (P1) in contact with the metal layer is T1 and the thickness of the main polyimide layer is T2, the thickness of T1 is preferably in the range of 1 μm to 4 μm, and the thickness of T2 is preferably in the range of 4 μm to 30 μm. From another viewpoint, the thickness of T1 is preferably 20% or less of the thickness of the insulating resin layer. Here, "main" means having the largest thickness among the multiple polyimide layers constituting the insulating resin layer, and preferably has a thickness of 60% or more, more preferably 70% or more, and even more preferably 80% or more of the thickness of the insulating resin layer. The main polyimide layer is preferably made of non-thermoplastic polyimide.

[0055] Furthermore, it is preferable that the entire insulating resin layer also satisfies all of the characteristic values ​​of the polyimide layer mentioned above.

[0056] <Method for manufacturing metal-clad laminates> As described above, the metal-clad laminate of the present invention is preferably prepared by forming an insulating resin layer consisting of one or more polyimide layers on a metal layer as a supporting substrate using a casting method or a sequential coating method, from the viewpoint of dimensional stability and other factors, but is not particularly limited. For example, an insulating resin layer (resin film) containing the polyimide layer of the present invention may be prepared, a seed layer may be formed by sputtering metal onto it, and then a metal layer may be formed by, for example, plating.

[0057] Alternatively, an insulating resin layer (resin film) composed of the polyimide of the present invention may be prepared and laminated with a metal foil by a method such as thermocompression bonding.

[0058] In those cases, in order to enhance the adhesiveness between the resin film and the metal layer, the surface of the resin film may be subjected to a modification treatment such as plasma treatment.

[0059] In addition, when manufacturing a metal-clad laminate having metal layers on both sides, for example, directly on the polyimide layer of the single-sided metal-clad laminate obtained by the above method, or, if necessary, after forming an adhesive layer that does not inhibit properties such as the transparency of the insulating resin layer, the metal layer can be obtained by laminating it by means such as thermocompression bonding. Regarding the hot press temperature in the case of thermocompression bonding the metal layer, it is not particularly limited, but it is preferably not lower than the glass transition temperature of the polyimide layer adjacent to the metal layer used. Also, regarding the hot press pressure, although it depends on the type of press equipment used, it is preferably in the range of 1 to 500 kg / m 2 .

[0060] (Peel strength) The 180° peel strength between the insulating resin layer and the metal layer in the metal-clad laminate of the present invention is preferably 0.3 kN / m or more, and more preferably 0.5 kN / m. In this specification, the evaluation of physical properties and characteristic values was measured under the conditions described in the examples, and those not particularly described are the measured values at room temperature (23°C).

[0061] <Circuit board> The metal-clad laminate of the present invention is mainly useful as a circuit board material for FPCs and the like. The circuit board of the present invention can be manufactured by processing the metal layer of the metal-clad laminate into a pattern by a conventional method to form a wiring layer. That is, the circuit board of the present invention comprises an insulating resin layer and a wiring layer provided on at least one surface of the insulating resin layer, wherein a part or all of the insulating resin layer is the above-mentioned polyimide layer (polyimide film). Furthermore, in order to improve the adhesion between the insulating resin layer and the wiring layer, the layer in contact with the wiring layer in the insulating resin layer is preferably a thermoplastic polyimide layer. [Examples]

[0062] The present invention will be described in detail below based on the examples, but the present invention is not limited to the scope of these examples. Examples 2, 3, and 4 are provided for reference only.

[0063] The abbreviations used in this example indicate the following compounds. BTDA:3,3',4,4'-benzophenonetetracarboxylic acid dianhydride BPDA: 3,3',4,4'-biphenyltetracarboxylic acid dianhydride PMDA: Pyromelit acid dianhydride DAPE: 4,4'-diaminodiphenyl ether BAPP: 2,2-bis(4-aminophenoxyphenyl)propane m-TB: 2,2'-dimethyl-4,4'-diaminobiphenyl TPE-R: 1,3-bis(4-aminophenoxy)benzene DABA:4,4'-diaminobenzanilide MABA: 4,4'-diamino-2'-methoxybenzanilide 3,4'-DAPE:3,4'-diaminodiphenyl ether TPE-Q: 1,4-bis(4-aminophenoxy)benzene DMAc: N,N-dimethylacetamide

[0064] Furthermore, the characteristics evaluated in the examples were assessed according to the evaluation method described below.

[0065] [Viscosity measurement] The viscosity of the polyamic acid solution was measured using a cone-plate viscometer with a constant-temperature water bath (manufactured by Tokimec Co., Ltd.). The measurement was taken at 25°C.

[0066] [Weight average molecular weight (Mw)] The measurements were performed using gel permeation chromatography (manufactured by Tosoh Corporation, product name: HLC-8220GPC). Polystyrene was used as the standard substance, and N,N-dimethylacetamide was used as the developing solvent.

[0067] [Thermal diffusivity in the thickness direction (α), thermal conductivity in the thickness direction (λz)] Polyimide resin film was cut to a size of 20 mm x 20 mm, and the thermal diffusivity α in the thickness direction was measured by laser flash method (NETZSCH, product name: Xenon Flash Analyzer LFA447 Nanoflash), specific heat was measured by differential scanning calorimetry (DSC), and density was measured by water displacement method. Based on these results, the thermal conductivity (W / m·K) was calculated. Due to the limitations of the measuring equipment, an 80 μm thick film was used for this measurement.

[0068] [Tear propagation resistance] A 63.5 mm x 50 mm polyimide resin film was used as a test specimen. A 12.7 mm long cut was made in the specimen, and the tear propagation resistance was measured using a light-load tear tester manufactured by Toyo Seiki Co., Ltd.

[0069] [End tear resistance] In accordance with Method B of JIS C2151 (2019), the edge tear resistance was measured using a polyimide film measuring 20 mm wide x 200 mm long as a test specimen, with a Strograph R1 manufactured by Toyo Seiki Co., Ltd.

[0070] [Tensile modulus of elasticity, tensile strength, tensile elongation] Test specimens of polyimide film (10 mm x 15 mm) were prepared, and tensile tests were performed using a Tensilon universal testing machine (Orientec Co., Ltd., RTA-250) at a tensile speed of 10 mm / min in accordance with IPC-TM-650, 2.4.19. The tensile modulus, tensile strength, and tensile elongation were calculated.

[0071] [Coefficient of thermal expansion (CTE)] A polyimide film (3 mm x 15 mm) was heated from 30°C to 280°C at a heating rate of 10°C / min while applying a 5.0 g load using a thermomechanical analyzer (TMA), and then cooled from 250°C to 100°C. The coefficient of thermal expansion was measured from the elongation (linear expansion) of the polyimide film during the cooling process.

[0072] [Thermal decomposition temperature (Td1)] Under a nitrogen atmosphere, polyimide films weighing 10-20 mg were heated at a constant rate from 30°C to 550°C using a SEIKO TG / DTA6200 thermogravimetric analyzer (TG). The weight change was measured, with the weight at 200°C set to zero, and the temperature at which the weight loss rate was 1% was defined as the thermal decomposition temperature (Td1).

[0073] [Peel strength] To measure the peel strength, the metal layer on the obtained metal-clad laminate was plated to 25 μm to prepare a laminate, and then a 1 mm pattern was fabricated on it. Using a tension tester, the polyimide film side of a sample with a 1 mm wide circuit obtained from the laminate was fixed to an aluminum plate with double-sided tape, and the copper foil was peeled off at a speed of 50 mm / min in a 180° direction to determine the peel strength.

[0074] Synthesis Examples 1-13 To synthesize polyamic acid solutions A to N, under a nitrogen atmosphere, DMAc solvent was added to a 500 ml separable flask to achieve the solid content concentration shown in Table 1. The diamine and acid anhydride components (molar parts) shown in Table 1 were then added, and the mixture was stirred at room temperature for 36 hours to carry out the polymerization reaction, thereby preparing viscous polyamic acid solutions A to N.

[0075] [Example 1] A polyamic acid solution A obtained in Synthesis Example 1 was applied to copper foil 1 (electrolytic copper foil, manufactured by Fukuda Metal Foil & Powder Industry Co., Ltd., product name: CF-T4MDS-HD-12, thickness: 12 μm, Rz = 1.4 μm) to a cured thickness of 21 μm. The solution was then heated and dried at 90 to 140 °C to remove the solvent. Subsequently, a metal-clad laminate (CCL) 1A was fabricated by gradually increasing the temperature in the temperature range of 130 to 360 °C over 30 minutes to laminate an insulating resin layer consisting of a polyimide layer onto the copper foil 1. To evaluate the properties of the polyimide layer in the metal-clad laminate 1A, the copper foil 1 was etched off to prepare a film 1a, and the tear propagation resistance, edge tear resistance, glass transition temperature (Tg), CTE, Td1, tensile modulus, tensile strength, tensile elongation, and peel strength were evaluated. Note that thermal diffusivity (α) and thermal conductivity (λ) z The measurement samples were prepared in the same manner as described above, except that the cured resin thickness was 80 μm.

[0076] (Examples 2-9, Comparative Examples 1-4) By changing the type and thickness of the polyamic acid solution used, metal-clad laminates 2B-9N and films 2b-9n according to Examples 2-9 using polyamic acid solutions B, C, D, E, K, L, M, or N were obtained, as well as metal-clad laminates 1G-4J and films 1g-4j according to Comparative Examples 1-4 using polyamic acid solutions G, H, I, or J, and were evaluated in the same manner as in Example 1. The evaluation results are shown in Tables 2-4.

[0077] [Table 1]

[0078] [Table 2]

[0079] [Table 3]

[0080] Table 4

Claims

1. A polyimide obtained by imidizing a polyamic acid, The polyamic acid is derived from an acid anhydride component represented by the following general formula (1), and Diamine residues derived from the diamine component represented by general formula (2) and It contains, The total amount of acid anhydride residues contains 50 mol% or more of acid anhydride residues derived from the acid anhydride component represented by the following general formula (1), The product contains 50 mol% or more of diamine residues derived from the diamine component represented by the following general formula (2), and 40 to 50 mol% of diamine residues derived from the diamine component represented by the following general formula (3), a) and c) below; a) The tear resistance measured at a width of 20 mm is within the range of 75 N to 500 N. c) The thermal diffusivity (α) in the thickness direction is within the range of 0.100 m² / s or more. A polyimide characterized by satisfying the following conditions. 【Chemistry 1】 【Chemistry 2】 [In formula (2), R independently represents a halogen atom, a C1-C6 alkyl or alkoxy group which may be substituted with a halogen atom, or a C1-C6 monovalent hydrocarbon or alkoxy group which may be substituted with a C1-C6 phenyl or phenoxy group. m and n independently represent the number of substitutions, where m is an integer from 0 to 4 and n is an integer from 0 to 4.] 【Transformation 3】 [In formula (3), Z represents -O-. R independently represents a halogen atom, a C1-C6 alkyl or alkoxy group which may be substituted with a halogen atom, or a C1-C6 monovalent hydrocarbon or alkoxy group which may be substituted with a C1-C6 monovalent hydrocarbon or alkoxy group. n1 represents the number of substitutions and is an integer from 0 to 4. n2 represents an integer from 0 to 3.]

2. b) below; b) The thermal conductivity (λz) in the thickness direction is within the range of 0.20 W / m·K or higher. The polyimide according to claim 1 that satisfies the requirements.

3. Furthermore, condition d) below; d) The glass transition temperature is 250°C or higher. The polyimide according to claim 1 or 2, characterized in that it satisfies the following conditions.

4. Furthermore, condition e) below; e) The tear propagation resistance is 3.0 kN / m or more. A polyimide according to any one of claims 1 to 3, characterized in that it satisfies the following conditions.

5. Furthermore, the following condition f); f) The coefficient of thermal expansion is 50 ppm / K or less. A polyimide according to any one of claims 1 to 4, characterized in that it satisfies the following conditions.

6. The polyimide according to any one of claims 1 to 5, characterized in that the polyamic acid contains 75 mol% or more of acid anhydride residues derived from the acid anhydride component represented by the general formula (1) with respect to the total acid anhydride residues.

7. The polyimide according to any one of claims 1 to 5, characterized in that the polyamic acid contains 100 mol% of acid anhydride residues derived from the acid anhydride component represented by the general formula (1) with respect to the total acid anhydride residues.

8. A metal-clad laminate comprising an insulating resin layer consisting of one or more layers, and a metal layer laminated on one or both sides of the insulating resin layer, A metal-clad laminate characterized in that at least one of the insulating resin layers is composed of a polyimide layer according to any one of claims 1 to 7.

9. A circuit board comprising an insulating resin layer consisting of one or more layers, and a conductive circuit layer laminated on one or both sides of the insulating resin layer, A circuit board in which at least one of the insulating resin layers is made of a polyimide layer according to any one of claims 1 to 7.

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