Copolymers, resin compositions, resin films, metal-clad laminates, circuit boards, electronic devices and electronic equipment.

Abstract

The present invention provides a copolymer with excellent heat resistance and excellent high-frequency transmission characteristics. [Solution] The copolymer according to the embodiment is a copolymer comprising a first structure containing two or more aromatic rings and a remaining structure, wherein the first structure is a structure in which the aromatic rings are bonded to each other by single bonds or linking groups, the mass ratio of the sum of carbon atoms and hydrogen atoms to the total mass of the remaining structure is 77 wt% or more, the mass ratio of carbon atoms to hydrogen atoms in the remaining structure is 6.5 or more and 12.5 or less, the mass ratio of the first structure to the total mass of the copolymer is 15 wt% or more and 85 wt% or less, and the number of atoms directly interposed in the bond between the aromatic rings in the linking group is 2 or less.

Description

Technical Field

[0001] The present disclosure relates to a copolymer, a resin composition, a resin film, a metal-clad laminate, a circuit board, an electronic device, and an electronic apparatus.

Background Art

[0002] In recent years, with the miniaturization and weight reduction of electronic devices, the application of flexible printed circuits (FPCs) that are thin, lightweight, and flexible has been expanding.

[0003] If the resin used for the insulating layer of a flexible printed circuit board has a large coefficient of thermal expansion, misalignment may occur during component mounting, so a resin with excellent heat resistance is required.

[0004] As a resin with excellent heat resistance, Patent Document 1 discloses a polyimide resin obtained by reacting a polymer obtained by reacting a styrene / maleic anhydride copolymer (A) with an aromatic amine and / or an aliphatic amine with an aromatic tetracarboxylic dianhydride and an aromatic diamine and / or an aliphatic diamine.

Prior Art Documents

Patent Documents

[0005] [[ID=3T]]

Patent Document 1

Non-Patent Documents

[0006]

Non-Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0007] However, using the resin described in Patent Document 1 in flexible printed circuit boards presented a challenge: the transmission loss at high frequencies was significant, limiting its applications.

[0008] This invention was made in view of the above circumstances, and aims to provide a copolymer with excellent heat resistance and excellent high-frequency transmission characteristics, as well as a resin composition containing the copolymer, a resin film, a metal-clad laminate, a circuit board, an electronic device, and an electronic device. [Means for solving the problem]

[0009] To solve the aforementioned problems, the present invention proposes the following means. (1) The copolymer of embodiment 1 of the present invention is A copolymer comprising a first structure containing two or more aromatic rings and a remainder structure, The first structure is a structure in which the aromatic rings are linked to each other by single bonds or linking groups, In the remaining structure, the mass ratio of the sum of carbon atoms and hydrogen atoms to the total mass of the remaining structure is 77 wt% or more. The mass ratio of carbon atoms to hydrogen atoms in the remaining structure is 6.5 or more and 12.5 or less. The mass ratio of the first structure to the total mass of the copolymer is 15 wt% or more and 85 wt% or less. In the aforementioned linking group, the number of atoms directly intervening in the bond between the aromatic rings is 2 or less. (2) Embodiment 2 of the present invention is the copolymer of Embodiment 1, The first structure is such that the total mass ratio of the imide structure and the amide acid structure is 15.5 wt% or more of the total mass of the first structure. (3) Embodiment 3 of the present invention is the copolymer of Embodiment 1, The remaining structure has a chain-like hydrocarbon structure in which six or more carbon atoms are bonded to each other by single bonds. (4) Embodiment 4 of the present invention is the copolymer of Embodiment 1, The difference in SP value between the first structure and the remaining structure is 3 (J / cm²). 3 ) 1 / 2 More than 10(J / cm3 ) 1 / 2 The following applies: (5) Embodiment 5 of the present invention is the copolymer of Embodiment 1, The difference between the product of δP and δH in the HSP values ​​of the first structure and the remaining structure is 50 (J / cm²). 3 ) or more 120 (J / cm 3 ) are as follows: (6) Embodiment 6 of the present invention is the copolymer of Embodiment 1, The copolymer is at least one of a block copolymer and a graft copolymer. (7) Embodiment 7 of the present invention is the copolymer of Embodiment 1, The mass ratio of the first structure to the remaining structure is 15:85 to 85:15. (8) Embodiment 8 of the present invention is the copolymer of Embodiment 1, The combined mass of the carbon atoms and hydrogen atoms is 90 wt% or more, and the mass ratio of the carbon atoms to the hydrogen atoms is 6.5 or more and 12.5 or less. (9) The resin composition of embodiment 9 of the present invention comprises the copolymer of embodiment 1. (10) The resin film of embodiment 10 of the present invention comprises the copolymer of embodiment 1. (11) The resin film of embodiment 11 of the present invention is the resin film of embodiment 10, When measured by a split-post dielectric resonator (SPDR) in an environment with a temperature of 24-26°C and a relative humidity of 45-55%, the dielectric loss tangent Df1 of the copolymer at 10 GHz and the second dielectric loss tangent Df2 calculated based on two or more repeating units constituting the copolymer satisfy the following equation (1): The second dielectric loss tangent is calculated from the addition law based on the dielectric loss tangent of the homopolymer of the repeating unit at 10 GHz and the mass ratio of the repeating unit. Df1 <Df2×0.97···(1) (12) Embodiment 12 of the present invention is a resin film of Embodiment 10, The linear thermal expansion coefficient at 180-100°C is 50 ppm / K or less. (13) The metal-clad laminate according to embodiment 13 of the present invention is 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, At least one layer of the insulating resin layer is made of the resin film according to embodiment 10. (14) The circuit board of embodiment 14 of the present invention is 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, At least one layer of the insulating resin layer is made of the resin film according to embodiment 10. (15) An electronic device according to embodiment 15 of the present invention comprises the circuit board according to embodiment 14. (16) The electronic device according to embodiment 16 of the present invention comprises the circuit board according to embodiment 14. [Effects of the Invention]

[0010] According to each of the above embodiments of the present invention, copolymers with excellent high-frequency transmission characteristics, resin compositions containing the copolymer, resin films, metal-clad laminates, circuit boards, electronic devices, and electronic equipment can be provided. [Modes for carrying out the invention]

[0011] The copolymer of this disclosure is a copolymer comprising a first structure containing two or more aromatic rings and a remainder structure. Here, a copolymer refers to a polymer produced by polymerizing two or more substrates.

[0012] (first structure) The first structure contains two or more aromatic rings. Here, an aromatic ring refers to a cyclic structure that satisfies Hückel's rule. Examples of aromatic rings include benzene rings, naphthalene rings, anthracene rings, pyrrole rings, pyridine rings, and thiophene rings. Preferably, the aromatic rings are composed only of carbon atoms and hydrogen atoms. Examples of such aromatic rings include benzene rings or fused rings of two or more benzene rings (naphthalene, anthracene, etc.). Having two or more aromatic rings in the first structure allows for the formation of an ordered structure through intermolecular interactions such as π-π interactions, for example, when a resin substrate such as a resin film is formed from the copolymer. This improves the tensile modulus of the resin substrate and lowers the linear thermal expansion coefficient (CTE). This improves the heat resistance of the resin substrate using the copolymer of this disclosure. Furthermore, the formation of this ordered structure suppresses molecular motion and reduces the dielectric loss tangent of the resin substrate. This improves the high-frequency transmission characteristics of the resin substrate using the copolymer of this disclosure.

[0013] The number of aromatic rings in the first structure is preferably 3 or more, more preferably 5 or more, and even more preferably 10 or more. The number of aromatic rings may be 14 or more. A larger number of aromatic rings is preferable because it can improve the effect of π-π interactions.

[0014] The first structure is one in which aromatic rings in the first structure are connected by single bonds (i.e., bonds in which the carbon atoms constituting one aromatic ring are directly bonded to the carbon atoms constituting the other aromatic ring) or by linking groups. In a linking group connecting aromatic rings, the number of atoms directly interposed in the bond between the aromatic rings is 2 or less. Having 2 or fewer atoms directly interposed in the bond between aromatic rings facilitates the formation of an ordered structure, allowing for lower linear thermal expansion coefficients (thermal expansion coefficients) and dielectric loss tangents. Here, "the number of atoms directly interposed in the bond between aromatic rings" refers to the total number of atoms on the shortest path connecting the aromatic rings. Here, "the bond between aromatic rings" refers to the bond existing between the aromatic rings, and "atoms on the shortest path connecting the aromatic rings" does not include the atoms that make up the aromatic rings. For example, when two benzene rings are bonded via a COO group, there will be one CC bond and two CO bonds. In this case, the atoms on the shortest path connecting the aromatic rings are a total of two: a carbon atom and an oxygen atom. In a linking group that connects aromatic rings, the number of atoms directly intervening in the bond between aromatic rings may be one or more.

[0015] In the first structure, examples of linking groups that connect aromatic rings include -O-, -CH2-, -CH2-CH2-, -CH(CH3)-, -C(CH3)2-, -C(CF3)2-, -CF2-, -COO-, -OOC-, -SO-, -SO2-, -S-, -CO-, and -CONH-.

[0016] Examples of the first structure include having a structure represented by the following formula (1) or a structure represented by the following formula (2). Y in formula (1) 1 This refers to a single bond (i.e., a bond in which one carbon atom in an aromatic ring is directly bonded to another carbon atom in an aromatic ring), a divalent linking group, or a structure represented by formula (3) below. In formula (1) below, * represents a bond.

[0017] Y 1The divalent linking group is not particularly limited as long as the number of atoms directly intervening in the bond between aromatic rings is 2 or less. Examples of the divalent linking group include -O-, -CH2-, -CH2-CH2-, -CH(CH3)-, -C(CH3)2-, -C(CF3)2-, -CF2-, -COO-, -OOC-, -SO-, -SO2-, -S-, -CO-, -CONH-, and the like.

[0018]

Chemical formula

[0019] Y in the following formula (2) 2 is a single bond, a divalent linking group, or a structure represented by the following formula (3). * in the following formula (2) represents a bond. Y 2 The divalent linking group of Y is not particularly limited as long as the number of atoms directly intervening in the bond between aromatic rings is 2 or less. Y 2 As the divalent linking group of Y, Y 1 the same ones as those can be used.

[0020] Ar in the following formula (2) 1 is a divalent aromatic imide ring-containing group having a structure in which a cyclic imide group is condensed with a divalent aromatic ring group or an aromatic ring. The aromatic ring contained in Ar 1 may have a substituent.

[0021] Ar in the following formula (2) 2 is a divalent aromatic imide ring-containing group having a structure in which a cyclic imide group is condensed with a divalent aromatic ring group or an aromatic ring. The aromatic ring contained in Ar 2 may have a substituent. Ar 1 and Ar 2 may be the same or different.

[0022] The substituents on the aromatic ring in formula (2) below are, for example, C1-C12 alkyl groups, C1-C12 alkoxy groups, phenyl groups, hydroxyl groups, or carboxyl groups. C1-C3 alkyl groups are preferred as substituents. The position of the substituent on the aromatic ring is not particularly limited. If the aromatic ring is unsubstituted, it is bonded to a hydrogen atom.

[0023] In equation (3) below, X 1 and X 2 X represents a divalent linking group or a single bond. 1 and X 2 Examples of linking groups include -O-, -CH2-, -CH2-CH2-, -CH(CH3)-, -C(CH3)2-, -C(CF3)2-, -CF2-, -COO-, -OOC-, -SO-, -SO2-, -S-, -CO-, -CONH-, etc. 1 and X 2 They may be the same or different. In the following formula (3), A represents a divalent group containing an aromatic ring such as a benzene ring or a naphthalene ring. The benzene ring and naphthalene ring may have any substituents. Examples of substituents include alkyl groups and alkoxy groups, with methyl groups and ethyl groups being preferred. The number of substituents is preferably 0 to 2.

[0024] [ka]

[0025] [ka]

[0026] The first structure preferably has at least one of an imide structure (imide bond) and an amidic acid structure.

[0027] The first structure preferably has a structure that includes an imide bond and an aromatic ring.

[0028] The structure containing the imide bond and the aromatic ring may be, for example, the structure represented by the following formula (4). The ring Ar of the following formula (4) 3 The above-mentioned aromatic ring is represented by *, and the asterisk (*) represents a bonding hand. Ring Ar 3 The aromatic ring may have substituents. Ring Ar 3 The substituents on the aromatic ring are, for example, C1-C12 alkyl groups, C1-C12 alkoxy groups, phenyl groups, hydroxyl groups, or carboxyl groups. For example, C1-C3 alkyl groups are preferred as substituents. Ring Ar 3 The position of substituents on the aromatic ring is not particularly limited. 3 It is preferable that a cyclic imide is formed with one side of one of the rings (for example, a benzene ring). In the case of an aromatic ring with multiple rings, such as an anthracene ring, two cyclic imides may be formed with the same ring, or one cyclic imide may be formed with each of different rings.

[0029] [ka]

[0030] The amidic acid structure included in the first structure is a structure consisting of a carboxyl group used to form an imide bond and an amide bond. The structure containing the amidic acid structure is preferably a structure represented by the following formula (5). The ring Ar of the following formula (5) 4 The above-mentioned aromatic ring is represented by *, and the asterisk (*) represents a bonding hand. Ring Ar 4 The aromatic ring may have substituents. Ring Ar 4 The substituents on the aromatic ring are, for example, C1-C12 alkyl groups, C1-C12 alkoxy groups, phenyl groups, hydroxyl groups, or carboxyl groups. For example, C1-C3 alkyl groups are preferred as substituents. Ring Ar 4 The position of substituents on the aromatic ring is not particularly limited. 4It is preferable that a carboxyl group and an amide bond are present so that a cyclic imide can be formed on one side of one of the rings (e.g., a benzene ring). In the case of an aromatic ring with multiple rings, such as an anthracene ring, the carboxyl group and amide bond may be present so that two cyclic imides are formed on the same ring, or so that one cyclic imide is formed on each of different rings.

[0031] [ka]

[0032] It is preferable that the total mass ratio of the imide structure (imide bond) and amide acid structure to the total mass of the first structure is 15.5 wt% or more. By having a total mass ratio of the imide structure (imide bond) and amide acid structure to the total mass of the first structure of 15.5 wt% (mass%) or more, the CTE can be reduced and the storage modulus at high temperatures can be improved, thereby providing heat resistance. It is preferable that the total mass ratio of the imide structure and amide acid structure to the total mass of the first structure is 18 wt% or more. It is preferable that the total mass ratio of the imide structure and amide acid structure to the total mass of the first structure is 35 wt% or less. It is more preferable that the total mass ratio of the imide structure and amide acid structure to the total mass of the first structure is 30 wt% or less. By having a total mass ratio of the imide structure and amide acid structure to the total mass of the first structure of 35 wt% or less, the deterioration of the dielectric loss tangent due to the imide group can be suppressed.

[0033] The total mass ratio of the imide and amide acid structures to the total mass of the first structure is calculated as follows: The imide structure is defined as (-(CO)2-N-) and the amide acid structure as (-CO2H, -CO2-NH-). The total mass of the imide and amide acid structures contained in the repeating units of the first structure is calculated. Next, the total mass of the repeating units of the first structure is calculated, and the total mass of the imide and amide acid structures is divided by the total mass to determine the mass ratio of the synthesis of the imide and amide acid structures. If the first structure has multiple repeating units, the calculation is performed for each repeating unit, and then a weighted average is taken using the mass ratio of each repeating unit to the entire first structure to calculate the total mass ratio of the imide and amide acid structures to the total mass of the first structure.

[0034] Specific examples of the first structure include structures consisting of repeating units that make up polymers such as all-aromatic polyimides (PI), non-thermoplastic polyimides, liquid crystal polymers (LCP), polyphenylene ethers (PPE), polyether ether ketones (PEEK), polyphenylene sulfides (PPS), polyamides, polyamide-imides, polyether sulfones (PES), polysulfones (PS), polybenzimidazoles (PBI), polybenzoxazoles (PBO), and polyarylates (PAR), as well as combinations thereof.

[0035] Here, we will explain more specifically using a non-thermoplastic polyimide or a precursor of a non-thermoplastic polyimide as an example of the first structure, but the first structure of the copolymer of this disclosure is not limited to a non-thermoplastic polyimide. A non-thermoplastic polyimide can be obtained by heat treatment of a precursor of a non-thermoplastic polyimide. In this specification, "non-thermoplastic polyimide" generally refers to a polyimide that does not soften or become adhesive when heated, but in this specification, a storage modulus of 1.0 × 10⁻⁶ at 30°C, as measured using a dynamic viscoelasticity analyzer (DMA), is used. 9 The storage modulus is 1.0 × 10⁻¹⁶ Pa or higher, and within a temperature range of glass transition temperature + 30°C. 8 This refers to polyimides exhibiting a Pa or higher rating.

[0036] The non-thermoplastic polyimide precursor contains tetracarboxylic acid residues and diamine residues. In this specification, a tetracarboxylic acid residue refers to a tetravalent group derived from tetracarboxylic dianhydride, and a diamine residue refers to a divalent group derived from a diamine compound. The polyimide preferably contains aromatic tetracarboxylic acid residues derived from aromatic tetracarboxylic dianhydride and aromatic diamine residues derived from aromatic diamines.

[0037] Tetracarboxylic acid anhydrides used in the synthesis of non-thermoplastic polyimide precursors can be used without particular limitation. Examples of such acid anhydrides include pyromellitic dianhydride (PMDA), 3,3',4,4'-biphenyltetracarboxylic acid dianhydride (BPDA), 2,3',3,4'-biphenyltetracarboxylic acid dianhydride, 4,4'-biphenol-bis(trimellitate anhydride), 3,3',4,4'-diphenylsulfonetetracarboxylic acid dianhydride, 4,4'-oxydiphthalic acid anhydride, 2,2',3,3'-, 2,3,3',4'- or 3,3',4,4'-benzophenonetetracarboxylic acid dianhydride, 2,3',3,4 '-diphenyl ether tetracarboxylic dianhydride, bis(2,3-dicarboxyphenyl) ether dianhydride, 3,3'',4,4''-, 2,3,3'',4''- or 2,2'',3,3''-p-terphenyl tetracarboxylic dianhydride, 2,2-bis(2,3- or 3,4-dicarboxyphenyl)-propane dianhydride, bis(2,3- or 3,4-dicarboxyphenyl)methane dianhydride, bis(2,3- or 3,4-dicarboxyphenyl) sulfone dianhydride, 1,1-bis(2,3- or 3,4-dicarboxyphenyl) Boxyphenyl)ethane dianhydride, 1,2,7,8-,1,2,6,7- or 1,2,9,10-phenanthrene-tetracarboxylic acid dianhydride, 2,3,6,7-anthracenetetracarboxylic acid dianhydride, 2,2-bis(3,4-dicarboxyphenyl)tetrafluoropropane dianhydride, 2,3,5,6-cyclohexane dianhydride, 2,3,6,7-naphthalenetetracarboxylic acid dianhydride (NTCDA), 1,2,5,6-naphthalenetetracarboxylic acid dianhydride, 1,4,5,8-naphthalenetetracarboxylic acid dianhydride , 4,8-dimethyl-1,2,3,5,6,7-hexahydronaphthalene-1,2,5,6-tetracarboxylic dianhydride, 2,6- or 2,7-dichloronaphthalene-1,4,5,8-tetracarboxylic dianhydride, 2,3,6,7-(or 1,4,5,8-)tetrachloronaphthalene-1,4,5,8-(or 2,3,6,7-)tetracarboxylic dianhydride, 2,3,8,9-,3,4,9,10-,4,5,10,11- or 5,6,11,12-perylene-tetracarboxylic dianhydride, cyclopentane-1,2,3,4-tetracarboxylic dianhydride, pyrazine-2,3,5,6-tetracarboxylic dianhydride, pyrrolidine-2,3,4,5-tetracarboxylic dianhydride, thiophene-2,3,4,5-tetracarboxylic dianhydride, 4,4'-bis(2,3-dicarboxyphenoxy)diphenylmethane dianhydride, ethylene glycol bis-anhydrotrimellitate, p-biphenylene bis(trimellitic acid monoester dianhydride) (BP-TME), 2,2',3,3',5,5'-hexamethyl[1,1'-biphenyl]-4,4'-diyl=bis(1,3-dioxo-1,3-dihydro-2 Examples of aromatic tetracarboxylic dianhydrides include -benzofuran-5-carboxylate) (TMPBP-TME), 2,6-naphthalenebis(trimellitic acid monoester anhydride) (26DHN-TME), 1,3-dihydro-1,3-dioxo-5,5'-(3,3'-dimethyl[1,1'-biphenyl]-4,4'-diyl) ester, 1,3-dihydro-1,3-dioxo-5,5'-(3,3',5,5'-tetramethyl[1,1'-biphenyl]-4,4'-diyl) ester, and 1,4-phenylenebis(trimellitic acid monoester) dianhydride (TAHQ). Among these, it is particularly preferable to use acid dianhydrides having an ester group in the molecule represented by the following general formula (6), or acid anhydrides having a biphenyl or naphthalene skeleton, such as 3,3',4,4'-biphenyltetracarboxylic dianhydride (BPDA) and 2,3,6,7-naphthalenetetracarboxylic dianhydride (NTCDA), which are expected to enhance the linearity of the polyimide molecular chain, improve the tensile modulus due to in-plane orientation, and provide a low CTE effect. These tetracarboxylic anhydrides can be used alone or in combination of two or more. Note that the tetracarboxylic dianhydride residue derived from the tetracarboxylic dianhydride represented by general formula (6) is sometimes referred to as "acid dianhydride residue (1)".

[0038] [ka]

[0039] In general formula (6), Ar represents a divalent group containing one or more aromatic rings, but it is preferably a divalent group selected from the following formula.

[0040] In general formula (6), Ar represents a divalent group containing one or more aromatic rings, but it is preferably a divalent group selected from the following formula.

[0041] [ka]

[0042] In the above formula, R1 represents an alkyl group having 1 to 3 carbon atoms, and m independently represents an integer from 0 to 4, but it is more preferable that there is no substituent (m=0).

[0043] Compounds represented by general formula (6) are ester-containing acidic dianhydrides, and despite having a relatively large molecular weight which allows for a reduction in imide group concentration, they can maintain a low coefficient of linear thermal expansion (CTE). Furthermore, the ester structure has the effect of conferring an ordered structure to the entire polymer through intermolecular interactions. In particular, when the molecule contains a biphenyl skeleton or a naphthalene skeleton and two ester structures (-CO-O-) bonded to the biphenyl skeleton or naphthalene skeleton, it is preferable because the rigidity of the biphenyl skeleton and naphthalene skeleton facilitates the formation of an ordered structure. Therefore, by including acidic dianhydride residue (1), it is possible to reduce the CTE (low CTE), and it also contributes to a decrease in the dielectric loss tangent (low dielectric loss tangent) by improving the ordered structure of the molecule and suppressing its motion.

[0044] Examples of tetracarboxylic dianhydrides represented by formula (6) above include p-biphenylenebis(trimellitic acid monoester dianhydride) (BP-TME), 2,2',3,3',5,5'-hexamethyl[1,1'-biphenyl]-4,4'-diyl=bis(1,3-dioxo-1,3-dihydro-2-benzofuran-5-carboxylate) (TMPBP-TME), and 2,6-naphthalenebis(trimellitic acid monoester Examples include acid anhydride (26DHN-TME), 1,3-dihydro-1,3-dioxo-5,5'-(3,3'-dimethyl[1,1'-biphenyl]-4,4'-diyl) ester, 1,3-dihydro-1,3-dioxo-5,5'-(3,3',5,5'-tetramethyl[1,1'-biphenyl]-4,4'-diyl) ester, and 1,4-phenylenebis(trimellitic acid monoester) dianhydride (TAHQ). Among these, BP-TME and 26DHN-TME are particularly preferred because they have a large effect in reducing CTE and dielectric loss tangent.

[0045] The amine compounds used in the synthesis of non-thermoplastic polyimide precursors can be used without restriction. Examples of such diamine compounds include 1,4-diaminobenzene (p-PDA; paraphenylenediamine), 2,2'-dimethyl-4,4'-diaminobiphenyl (m-TB), 2,2'-diethyl-4,4'-diaminobiphenyl (m-EB), 2,2'-diethoxy-4,4'-diaminobiphenyl (m-EOB), 2,2'-dipropoxy-4,4'-diaminobiphenyl (m-POB), 2,2'-di-n-propyl-4,4'-diaminobiphenyl (m-NPB), and 2,2'-divinyl-4,4'-diaminobiphenyl (VAB). 4,4'-diaminobiphenyl, 4,4'-diamino-2,2'-bis(trifluoromethyl)biphenyl (TFMB), 4-aminophenyl-4'-aminobenzoate (APAB), 3,3'-diaminodiphenylmethane, 3,3'-diaminodiphenylpropane, 3,3'-diaminodiphenyl sulfide, 3,3'-diaminodiphenyl sulfone, 3,3'-diaminodiphenyl ether, 3,4'-diaminodiphenyl ether, 3,4'-diaminodiphenylmethane, 3,4'-diaminodiphenylpropane, 3,4'-diaminodiphenyl Lusulfide, 3,3'-diaminobenzophenone, (3,3'-bisamino)diphenylamine, 1,4-bis(3-aminophenoxy)benzene, 3-[4-(4-aminophenoxy)phenoxy]benzeneamine, 3-[3-(4-aminophenoxy)phenoxy]benzeneamine, 1,3-bis(4-aminophenoxy)benzene (TPE-R), 1,3-bis(3-aminophenoxy)benzene (APB), 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[4,4'-(3-aminophenoxy)]benzanilide, 4-[3-[4-(4-aminophenoxy)phenoxy]phenoxy]aniline, 4,4'-[oxybis(3,1-phenyleneoxy)]bisaniline, bis[4-(4-aminophenoxy)phenyl]ether (BAPE), bis[4-(4-aminophenoxy)phenyl]sulfone (BAPS), bis[4-(4-aminophenoxy)phenyl]ketone (BAPK), 2,2-Bis-[4-(3-aminophenoxy)phenyl]propane, 2,2-Bis[4-(4-aminophenoxy)phenyl]propane (BAPP), Bis[4-(3-aminophenoxy)phenyl]sulfone, Bis[4-(3-aminophenoxy)phenyl]methane, Bis[4-(3-aminophenoxy)phenyl]ether, Bis[4-(3-aminophenoxy)]benzophenone, 9,9-Bis[4-(3-aminophenoxy)phenyl]fluorene, 2,2-Bis-[4-(4-aminophenoxy)phenyl]hexafluoropropane Pan, 2,2-bis-[4-(3-aminophenoxy)phenyl]hexafluoropropane, 3,3'-dimethyl-4,4'-diaminobiphenyl, 4,4'-methylenedi-o-toluidine, 4,4'-methylenedi-2,6-xylidine, 4,4'-methylene-2,6-diethylaniline, 3,3'-diaminodiphenylethane, 3,3'-diaminobiphenyl, 3,3'-dimethoxybenzidine, 4,4''-diamino-p-terphenyl, 3,3''-diamino-p-terphenyl, 4,4'-[1,4-phenylenebis(1-methyl Ethylidene)bisaniline, 4,4'-[1,3-phenylenebis(1-methylethylidene)]bisaniline, bis(p-aminocyclohexyl)methane, bis(p-β-amino-t-butylphenyl)ether, bis(p-β-methyl-d-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, 2'-methoxy-4,4'-diaminobenzanilide, 4,4'-diaminobenzanilide, 1,3-bis[2-(4-aminophenyl)-2-propyl]benzene, 1,4-bis[2-(4-aminophenyl)-2-propyl]benzene, 1,4-bis(4-aminophenoxy)-2,Examples of aromatic diamine compounds include 5-di-tert-butylbenzene, 6-amino-2-(4-aminophenoxy)benzoxazole, 2,6-diamino-3,5-diethyltoluene, 2,4-diamino-3,5-diethyltoluene, 2,4-diamino-3,3'-diethyl-5,5'-dimethyldiphenylmethane, and bis(4-amino-3-ethyl-5-methylphenyl)methane. Among these, diamines represented by the following general formula (7) and diamines having a naphthalene skeleton are particularly preferred, as they enhance the linearity of the polyimide molecular chain and are expected to provide a low CTE effect due to in-plane orientation. These diamine compounds can be used individually or in combination of two or more. In this specification, the diamine residue derived from the diamine compound represented by general formula (7) may be referred to as "diamine residue (2)".

[0046] [ka]

[0047] In formula (7), the linking group X represents a divalent group selected from a single bond, -CONH-, or -COO-, Y independently represents hydrogen, a monovalent hydrocarbon group having 1 to 3 carbon atoms, or an alkoxy group, n represents an integer from 0 to 2, and p and q independently represent integers from 0 to 4.

[0048] Preferred examples of the diamine compound represented by formula (7) above include 1,4-phenylenediamine, 1,2-phenylenediamine, 1,3-phenylenediamine, 2,2'-dimethyl-4,4'-diaminobiphenyl (m-TB), 2,2'-diethyl-4,4'-diaminobiphenyl (m-EB), 2,2'-diethoxy-4,4'-diaminobiphenyl (m-EOB), 2,2'-dipropoxy-4,4'-diaminobiphenyl (m-POB), 2,2'-di-n-propyl-4,4'-diaminobiphenyl (m-NPB), 2,2'-divinyl-4,4'-diaminobiphenyl (VAB), 4,4'-diaminobiphenyl, and 4,4''-diamino-p-terphenyl. Among these, 2,2'-dimethyl-4,4'-diaminobiphenyl (m-TB) is the most preferred as it has a significant effect in lowering the CTE of the resin film and reducing the dielectric loss tangent.

[0049] The non-thermoplastic polyimide precursor's properties, such as hygroscopicity, dielectric properties, toughness, CTE, storage modulus, and tensile modulus, can be controlled by selecting the types of tetracarboxylic dianhydride residues and diamine residues, and the molar ratio of each when it contains two or more types of tetracarboxylic dianhydride residues or diamine residues. In the non-thermoplastic polyimide precursor, if there are multiple structural units (constituent units), they may exist as blocks or randomly, but random arrangement is preferable.

[0050] In non-thermoplastic polyimide precursors, the tetracarboxylic dianhydride residues and diamine residues are preferably composed of aromatic tetracarboxylic dianhydride residues derived from aromatic tetracarboxylic dianhydride and aromatic diamine residues derived from aromatic diamine.

[0051] The non-thermoplastic polyimide precursors of this disclosure can be synthesized by known methods. For example, the non-thermoplastic polyimide precursors can be produced by reacting the above-mentioned tetracarboxylic anhydride with a diamine compound in a solvent. The non-thermoplastic polyimide precursors (polyamic acid) of this disclosure can be obtained by dissolving the tetracarboxylic anhydride and the diamine compound in approximately equimolar amounts in an organic solvent and allowing them to polymerize by stirring at a temperature in the range of 0 to 100°C for 30 minutes to 24 hours. In the reaction, the reactants (tetracarboxylic anhydride compound and diamine compound) are dissolved in the organic solvent in a range of 5 to 50% by mass, preferably in the range of 10 to 40% by mass, so that the resulting precursor is in the range of 5 to 50% by mass. Examples of organic solvents used in the polymerization reaction include N,N-dimethylformamide (DMF), N,N-dimethylacetamide (DMAc), N,N-diethylacetamide, N-methyl-2-pyrrolidone (NMP), 2-butanone, dimethyl sulfoxide (DMSO), hexamethylphosphoramide, N-methylcaprolactam, dimethyl sulfate, cyclohexanone, methylcyclohexane, dioxane, tetrahydrofuran, diglyme, triglime, methanol, ethanol, benzyl alcohol, and cresol. Two or more of these solvents can be used in combination, and aromatic hydrocarbons such as xylene and toluene can also be used in combination. There are no particular restrictions on the amount of such organic solvents used, but it is preferable to adjust the amount used so that the concentration of the solution of the non-thermoplastic polyimide precursor obtained by the polymerization reaction is about 5 to 50% by mass.

[0052] The synthesized non-thermoplastic polyimide precursor generally exhibits excellent solvent solubility, making it advantageous to use as a reaction solvent solution. However, it can be concentrated, diluted, or replaced with other organic solvents as needed. The viscosity of the non-thermoplastic polyimide precursor solution is preferably in the range of 100 cP to 100,000 cP.

[0053] The mass ratio of the first structure to the total mass of the copolymer of this disclosure is 15 wt% or more and 85 wt% or less. By having a mass ratio of the first structure to the total mass of the copolymer of this disclosure of 15 wt% or more and 85 wt% or less, the coefficient of linear thermal expansion of the resin substrate made of the copolymer of this disclosure can be reduced, and positional displacement during component mounting can be suppressed. Preferably, the mass ratio of the first structure to the total mass of the copolymer of this disclosure is 20 wt% or more. Preferably, the mass ratio of the first structure to the total mass of the copolymer of this disclosure is 30 wt% or more. Preferably, the mass ratio of the first structure to the total mass of the copolymer of this disclosure is 80 wt% or less. Preferably, the mass ratio of the first structure to the total mass of the copolymer of this disclosure is 75 wt% or less.

[0054] "Method for determining the first structure" In the copolymer of the present disclosure, the first structure is a structure that includes two or more aromatic rings, wherein the aromatic rings are linked to each other by single bonds or linking groups, and the number of atoms directly interposed in the bond between the aromatic rings at the linking group is two or less. For example, a mixture of the structure represented by formula (1) and the structure represented by formula (2) may be used. Furthermore, if there is an aromatic ring (aromatic ring A) at the end of the bond represented by formula (1), and the aromatic ring in formula (1) and aromatic ring A are linked by a single bond or the aforementioned linking group, then aromatic ring A is also included in the first structure. If the number of atoms directly interposed in the bond connecting the aromatic ring (aromatic ring B) included in the first structure to the next aromatic ring is four or more, then aromatic ring B is considered the end of the first structure. That is, the first structure has aromatic rings at both ends. Here, if the aromatic rings have a ring structure that shares one side of the aromatic ring, as in formula (1), then the ring structure that shares one side of the aromatic ring is also considered part of the first structure (here, the cyclic imide portion). Furthermore, if the structure of the repeating unit is clear, that repeating unit may be considered the first structure. Also, if the proportion of monomers used in the synthesis of each copolymer is clear, it may be calculated from the proportion of each monomer used.

[0055] (Remaining structure) The remaining structure is a structure other than the first structure. That is, the copolymer of the present disclosure consists of the first structure and the remaining structure. In the remaining structure, the mass ratio of the sum of carbon atoms and hydrogen atoms in the remaining structure to the total mass of the remaining structure is 77 wt% or more. By having a mass ratio of the sum of carbon atoms and hydrogen atoms to the total mass of the remaining structure of 77 wt% or more, the dielectric loss tangent can be reduced and the high-frequency transmission characteristics can be improved. Preferably, the mass ratio of the sum of carbon atoms and hydrogen atoms to the total mass of the remaining structure is 83 wt% or more. More preferably, the mass ratio of the sum of carbon atoms and hydrogen atoms to the total mass of the remaining structure is 88 wt% or more. Particularly preferably, the mass ratio of the sum of carbon atoms and hydrogen atoms to the total mass of the remaining structure is 91.5 wt% or more. More preferably, the mass ratio of the sum of carbon atoms and hydrogen atoms to the total mass of the remaining structure is 95% or more. The mass ratio of the sum of carbon atoms and hydrogen atoms to the total mass of the remaining structure may be 100%. By reducing the proportion of atoms other than carbon atoms and hydrogen atoms, such as nitrogen and oxygen atoms, which tend to increase polarity in the remaining structure, the effect of reducing the dielectric loss tangent can be further improved. It is preferable that the mass ratio of the sum of carbon atoms and hydrogen atoms to the total mass of the remaining structure is 99 wt% or less.

[0056] The mass ratio (C / H) of carbon atoms (C) to hydrogen atoms (H) in the remaining structure is 6.5 or more and 12.5 or less. Having a mass ratio (C / H) of carbon atoms (C) to hydrogen atoms (H) in the remaining structure of 6.5 or more and 12.5 or less can reduce the polarity of the copolymer and further improve high-frequency transmission characteristics. A mass ratio (C / H) of carbon atoms (C) to hydrogen atoms (H) in the remaining structure of 10 or less is more preferable. A mass ratio (C / H) of carbon atoms (C) to hydrogen atoms (H) in the remaining structure of 8 or less is more preferable.

[0057] It is preferable that the mass ratio of oxygen atoms (O) to the sum of carbon atoms (C) and hydrogen atoms (H) in the remaining structure (O / C+H) is 0.20 or less. By having a mass ratio of oxygen atoms (O) to the sum of carbon atoms (C) and hydrogen atoms (H) in the remaining structure (O / C+H) of 0.20 or less, the polarity of the copolymer can be reduced, and the high-frequency transmission characteristics can be further improved. It is preferable that the mass ratio of oxygen atoms (O) to the sum of carbon atoms (C) and hydrogen atoms (H) in the remaining structure (O / C+H) is 0.10 or less.

[0058] It is preferable that the mass ratio of nitrogen atoms (N) to the sum of carbon atoms (C) and hydrogen atoms (H) in the remaining structure (N / C+H) is 0.20 or less. By having a mass ratio of nitrogen atoms (N) to the sum of carbon atoms (C) and hydrogen atoms (H) in the remaining structure (N / C+H) of 0.20 or less, the polarity of the copolymer can be reduced, and the high-frequency transmission characteristics can be further improved. It is preferable that the mass ratio of nitrogen atoms (N) to the sum of carbon atoms (C) and hydrogen atoms (H) in the remaining structure (N / C+H) is 0.10 or less.

[0059] The remaining structure preferably has a chain-like structure in which carbon atoms are linked to each other by single bonds. The number of carbon atoms constituting the chain-like structure (first chain-like structure) of the remaining structure is preferably 6 or more. The chain-like structure of the remaining structure may be a linear structure in which carbon atoms are linked in a line, or it may be a branched molecular chain or a cyclic structure in which carbon atoms are branched.

[0060] The number of carbon atoms constituting the first chain structure is preferably 6 or more. More preferably 10 or more, and even more preferably 20 or more. By increasing the number of carbon atoms constituting the first chain structure, the dielectric loss tangent can be reduced.

[0061] The carbon atoms constituting the first chain structure are preferably bonded to hydrogen atoms in addition to carbon atoms. The first chain structure may also consist of repeating units, such as -CH2-.

[0062] The first chain structure may have side chains. Here, a side chain refers to an oligomer-sized branch extending from the first chain structure. Examples of side chains include aryl groups such as phenyl groups, maleimide groups, allyl groups, and phosphate groups.

[0063] The remaining structure may include, for example, modified polystyrene, modified polyolefin, modified cycloolefin polymer, modified styrene-based elastomer, polyimide, polyamide, maleimide, polyester, polyurethane, polymethylpentene, and copolymers thereof. Examples of functional groups to be modified include acid anhydride groups (derived from maleic anhydride), amino groups, vinyl groups, ethynyl groups, carboxyl groups, hydroxyl groups, and thiol groups. From the viewpoint of functional group polarity and ease of modification, acid anhydride groups, amino groups, and vinyl groups are preferred. Examples of modified polystyrene include modified polystyrene, modified styrene-ethylene copolymer, and modified styrene-divinylbenzene copolymer. Examples of modified polyolefins include modified polyethylene, modified polypropylene, modified ethylene-polypropylene, modified propylene-butene copolymer, and modified propylene-ethylene-butene copolymer. Examples of modified cycloolefin polymers include modified polynorbornene and modified norbornene-ethylene copolymer. Examples of modified styrene-based elastomers include modified styrene-butadiene-styrene block copolymer (SBS), modified styrene-butadiene-butylene-styrene block copolymer (SBBS), modified styrene-ethylene-butylene-styrene block copolymer (SEBS), modified styrene-ethylene-propylene-styrene block copolymer (SEPS), and modified styrene-ethylene-ethylene·propylene-styrene block copolymer (SEEPS). If the remaining structure contains multiple structural units (constituent units), these constituent units may exist as blocks or randomly. The remaining structure may also contain components other than those mentioned above, as long as the conditions for the remaining structure are satisfied.

[0064] Examples of copolymers include alternating copolymers, random copolymers, block copolymers, and graft copolymers. The copolymer is preferably at least one of a block copolymer and a graft copolymer. Here, a graft copolymer is a polymer in which one polymer acts as the trunk, and other types of polymers are attached as branches to the trunk polymer. A block copolymer is a polymer consisting of two or more types of repeating units, in which polymer chains consisting of the same type of repeating units are bonded within a single chain. The inclusion of at least one of a block copolymer and a graft copolymer allows for the formation of a three-dimensional structure and suppresses the movement between molecular chains, thereby further reducing the coefficient of linear thermal expansion. Furthermore, suppressing the movement of molecular chains reduces the responsiveness to electric fields and lowers the dielectric loss tangent. Here, if the target structure (copolymer) contains polymer chains consisting of the same type of repeating units, the target structure is determined to be a block copolymer. Similarly, if the target structure (copolymer) contains different types of molecular chains branching off from the main chain, the target structure is determined to be a graft copolymer. If the target structure (copolymer) contains polymer chains made of the same type of repeating units, and also contains different types of molecular chains branched off from the main chain, then the copolymer is determined to be both a block copolymer and a graft copolymer.

[0065] (Method for determining the remaining structure) In the copolymer of this disclosure, the portion that was not determined to be the first structure in the above determination of the first structure (the remainder) is determined to be the remainder structure.

[0066] (first structure and remaining structure) The difference (absolute value of the difference) between the SP value (solubility parameter) of the primary structure and the residual structure is 3 (J / cm²). 3 ) 1 / 2 More than 10(J / cm 3 ) 1 / 2 Preferably, the following conditions are met: The difference in SP values ​​(solubility parameter) between the first structure and the remaining structure is 3 (J / cm²). 3 ) 1 / 2 More than 10(J / cm 3 ) 1 / 2The following conditions make it easier for the first structure to exist around the remaining structure, thus lowering the dielectric loss tangent and the linear thermal expansion coefficient (CTE). The difference in SP value (solubility parameter) between the first structure and the remaining structure is 3 (J / cm²). 3 ) 1 / 2 The above is preferable. The difference in SP value (solubility parameter) between the first structure and the remaining structure is 9 (J / cm²). 3 ) 1 / 2 The following is preferable:

[0067] The SP values ​​(solubility parameters) of the primary structure and the remaining structure can be calculated based on the Fedors method described in Non-Patent Document 1. The SP value δ by the Fedors method is calculated from the following formula (A1). In the following formula (1), E is the cohesive energy (J / mol) and V is the molecular capacity (cm³). 3 This means ( / mol). The SP value can be determined by calculating the cohesive energy and molecular capacity for each structure constituting the resin, and then raising the value obtained by dividing the sum of the cohesive energies of each component by the sum of the molecular capacities to the power of 1 / 2. For example, if the first structure is polyimide and polyamic acid, it is preferable to consider the acid-amine ratio and calculate using the imide structure and amidic acid structure. δ = (E / V) 1 / 2 ...(A1)

[0068] The difference in the product of δP and δH (δP × δH) in Hansen's solubility parameters (HSP values) between the first structure and the remaining structure (δP × δH of the first structure - δP × δH of the remaining structure) is 50 (J / cm²). 3 ) or more 120 (J / cm 3 It is preferable that the ratio is 50 (J / cm²) or less. Here, δP represents the polarity term and δH represents the hydrogen bonding term. The ratio of δP × δH of the first structure to δP × δH of the remaining structure is 50 (J / cm²). 3 ) or more 120 (J / cm 3 By keeping the value below this, the first structure is more likely to exist around the remaining structure, making it easier to lower the dielectric loss tangent and the linear thermal expansion coefficient (CTE).

[0069] The HSP values ​​δP and δH of the primary structure and the remaining structure can be calculated using commercially available software. For example, δP and δH can be calculated using the Hansen Solubility Parameter in Practice (HSPiP) software developed by Dr. Hansen.

[0070] In the copolymer of this disclosure, the mass ratio of the first structure to the remaining structure (first structure:remaining structure) is preferably 15:85 to 85:15. A mass ratio of 15:85 to 85:15 makes it easier to lower the dielectric loss tangent while lowering the CTE. A mass ratio of 25:75 to 75:25 is more preferable.

[0071] (Mass ratio of the first structure) The primary structure and the residual structure can be determined by identifying the chemical structure of the copolymer using known methods and judged according to the above criteria. Identification can be performed, for example, by nuclear magnetic resonance analysis if the copolymer is soluble. 1 H-NMR, 13 Analysis can be performed using methods such as 1C-NMR. After identifying the chemical structure of the copolymer, the first structure is determined from the obtained structure according to the above criteria. The portion not assigned to the first structure is considered the remaining structure, and the mass percentage of each structure can be determined by calculating the molecular weight of each structure. If the copolymer is insoluble, the mass percentage of each structure may be calculated by decomposing it to the monomer level and determining the ratio of monomers.

[0072] The weight-average molecular weight of the copolymer is preferably 500,000 or less. It is preferable that the weight-average molecular weight of the copolymer is 300,000 or less. It is even more preferable that the weight-average molecular weight of the copolymer is 250,000 or less. A smaller weight-average molecular weight of the copolymer alters the phase separation state of the resin composition, making it easier to achieve a homogeneous phase. Furthermore, in the case of a coating liquid, viscosity adjustment becomes easier.

[0073] The number-average molecular weight of the copolymer is preferably 250,000 or less. It is preferable that the number-average molecular weight of the copolymer is 200,000 or less. It is even more preferable that the number-average molecular weight of the copolymer is 100,000 or less. When the number-average molecular weight of the copolymer is small, the phase separation state of the resin composition changes, and it tends to become a homogeneous phase.

[0074] "Measurement of weight-average molecular weight (Mw) and number-average molecular weight (Mn)" The weight-average molecular weight and number-average molecular weight are measured by gel permeation chromatography (e.g., HLC-8420GPC, manufactured by Tosoh Corporation). Polystyrene is used as the standard substance, and the developing solvent can be appropriately selected according to the solubility of the resin. Suitable solvents include tetrahydrofuran (THF) and N,N-dimethylacetamide (DMAc).

[0075] The copolymer of the present disclosure may be obtained by selecting a substrate (monomer) to obtain the first structure and the remaining structure described above and polymerizing it by a known method, or by bonding the ends of the polymers together by a known reaction, or by extending the polymer by reacting it from the ends using a substrate that reacts with the ends of the polymer. For example, it may be produced by adding a resin solution of the remaining structural component to a resin solution of the first structural component and mixing them, or by adding a raw material monomer of the first structural component to a resin solution of the remaining structural component and mixing them. A solvent may be added together with the raw material monomer to be added. In the following description, polyimide will be used as an example, but the present invention is not limited to polyimide.

[0076] The first structural component's end can be adjusted to be either acid-terminated or amine-terminated by the molar ratio of the tetracarboxylic anhydride component and the diamine component in the raw materials. For example, by setting the molar ratio of the tetracarboxylic anhydride component to the diamine component (tetracarboxylic anhydride component / diamine component) to less than 1.0, the first structural component can be made amine-terminated. On the other hand, by setting the molar ratio of the tetracarboxylic anhydride component to the diamine component (tetracarboxylic anhydride component / diamine component) to a range greater than 1.0, the end of the first structural component can be made acid-terminated.

[0077] When preparing the first structural component (in this case, non-thermoplastic polyimide), there are no particular restrictions on the order in which the raw material monomers are added; they may be added simultaneously or in a predetermined order.

[0078] The method for producing the copolymer of this disclosure will be described in more detail below, using the case where the copolymer of this disclosure is produced using the raw materials of the remaining structural component and the first structural component as a representative example. In this case, the method for producing the copolymer of this disclosure is: Step 1 involves preparing a resin solution of the remaining structural components, Step 2 involves adding the first raw material monomer of the first structural component to the resin solution of the remaining structural component to prepare a mixed solution. The process includes step 3, which involves adding a second raw material monomer that reacts with a first raw material monomer to the mixed solution to synthesize a copolymer.

[0079] (Resin composition) The resin compositions of this disclosure include copolymers of this disclosure.

[0080] "Optional ingredients" In addition to the copolymer of this disclosure, the resin composition may optionally contain organic fillers, inorganic fillers, cyclizing agents, curing agents, curing accelerators, plasticizers, elastomers, coupling agents, pigments, flame retardants, heat dissipators, etc., as long as they do not impair the effects of the invention. Examples of inorganic fillers include silicon dioxide, aluminum oxide, beryllium oxide, niobium oxide, titanium oxide, magnesium oxide, boron nitride, aluminum nitride, silicon nitride, aluminum fluoride, calcium fluoride, magnesium fluoride, potassium silicofluoride, and metal phosphinate salts. These can be used individually or in combination of two or more.

[0081] The resin composition of this disclosure exhibits excellent flexibility and thermoplasticity when used to form an adhesive layer. Therefore, it has desirable properties for applications such as insulating layer materials in circuit boards, including FPCs, rigid substrates, rigid-flex substrates, multilayer substrates, build-up substrates, and high-frequency substrates, as well as coating agents.

[0082] <Resin substrate> The resin substrates of this disclosure include the copolymers of this disclosure. The resin substrates of this disclosure may be formed from the resin compositions of this disclosure. The shape of the resin substrates of this disclosure is not particularly limited. The shape of the resin substrates may be, for example, film-like, plate-like, or layer-like. A film-like substrate film will be described in more detail below as an example.

[0083] <Resin film> The resin film of this disclosure is a resin film consisting of one or more layers, wherein at least one layer contains a copolymer. Preferably, the resin film of this disclosure includes a resin layer made of the resin composition of this disclosure. Since the resin film of this disclosure has a layer made of the resin composition of this disclosure, it has excellent tensile modulus and high-frequency properties.

[0084] The method for manufacturing the resin film of this disclosure is not particularly limited, and known methods can be used, but it is preferable to manufacture it by repeatedly applying and drying the resin composition of this disclosure onto a support substrate one or more times. The method for applying the resin composition of this disclosure onto the support substrate is not particularly limited, and it can be applied using a coater such as a comma, die, knife, or lip. Furthermore, by using metal foil as the support substrate, the metal-clad laminate of this disclosure described later can be manufactured.

[0085] The resin film of this disclosure may be a film (sheet) made solely of insulating resin, or it may be an insulating resin film laminated on a substrate such as copper foil, glass plate, polyimide film, polyamide film, polyester film, or other resin sheet.

[0086] The resin film of this disclosure preferably has a thickness in the range of 5 to 150 μm, and more preferably in the range of 8 to 125 μm. If the thickness of the resin film of this disclosure is less than 5 μm, problems such as wrinkles may occur during transportation in the manufacturing of the resin film, and sufficient toughness may not be achieved, resulting in a film that does not have self-supporting properties. On the other hand, if the thickness of the resin film exceeds 150 μm, there is a risk of a decrease in the productivity of the resin film.

[0087] Linear thermal expansion coefficient (CTE) The resin film of this disclosure preferably has a CTE of 50 ppm / K or less, and more preferably in the range of 0 to 30 ppm / K. Having a CTE of 50 ppm / K or less allows for easy control of the dimensional change rate when used as a resin film or metal-clad laminate.

[0088] "Measurement of linear thermal expansion coefficient" The linear thermal expansion coefficient of a resin can be measured by the following method: Using a thermomechanical analyzer (for example, Hitachi High-Tech Technology Corporation (formerly Seiko Instruments Corporation), product name: TMA / 7100), a sample (3 mm wide x 20 mm long) is heated from 30°C to 180°C at a constant heating rate while a 5.0 g load is applied, and then it is held at that temperature for 10 minutes, after which it is cooled at a rate of 5°C / min, and the average thermal expansion coefficient (linear thermal expansion coefficient) from 180°C to 100°C is determined.

[0089] "Relative permittivity" The resin film disclosed herein has a relative permittivity (Dk) at 10 GHz after 24 hours of conditioning under conditions of temperature 24-26°C and relative humidity 45-55%, preferably 3.5 or less, and more preferably 3.0 or less, in order to ensure impedance matching when used in circuit boards such as FPCs and to reduce electrical signal loss. If this relative permittivity exceeds 3.5, problems such as electrical signal loss are likely to occur in the high-frequency signal transmission path when used in circuit boards such as FPCs. The relative permittivity can be measured by the method described above.

[0090] "Dielectric loss tangent" Furthermore, in order to reduce electrical signal loss when the resin film of this disclosure is used in circuit boards such as FPCs, the dielectric loss tangent (Tanδ) at 10 GHz, measured by a split-post dielectric resonator (SPDR) after 24 hours of humidity control under conditions of temperature: 24-26°C and relative humidity: 45-55%, is preferably 0.0030 or less, more preferably 0.0025 or less, and most preferably 0.0023 or less. If the dielectric loss tangent exceeds 0.0030, problems such as electrical signal loss are more likely to occur in the transmission path of high-frequency signals when used in circuit boards such as FPCs.

[0091] The relative permittivity and dielectric loss tangent can be evaluated by the following method. A resin film is obtained by molding a resin composition into a film. The molding method is not particularly limited. For example, a resin film for evaluation may be obtained by dissolving the resin composition in a solvent, preparing a coating solution, applying it to a support substrate, and drying it. Next, the relative permittivity (Dk) and dielectric loss tangent (Df) of the resin film at a predetermined frequency (e.g., 10 GHz) are measured using a vector network analyzer (e.g., Agilent, trade name: E8363C) and a split-post dielectric resonator (SPDR resonator). The relative permittivity and dielectric loss tangent should be measured after leaving the film used for measurement for 24 hours under conditions of a temperature of 24-26°C and a relative humidity of 45-55%.

[0092] It is preferable that the dielectric loss tangent Df1 (dielectric loss tangent at 10 GHz) of the resin film containing the copolymer and the second dielectric loss tangent Df2 (dielectric loss tangent at 10 GHz), calculated based on two or more repeating units constituting the copolymer, satisfy the following formula (A2). When the dielectric loss tangent Df1 (dielectric loss tangent at 10 GHz) of the copolymer and the second dielectric loss tangent Df2, calculated based on two or more repeating units constituting the copolymer, satisfy the following formula (A2), dielectric loss when using high-frequency signals can be reduced more effectively. Here, the second dielectric loss tangent Df2 is calculated from the following formula (A3) (additive rule) based on the dielectric loss tangent (Dfn) of the repeating unit homopolymer at 10 GHz and the mass ratio (mn / M) of the repeating unit. In formula (A3), N is the total number of components, n is from 1 to N, Dfn is the dielectric loss tangent of the nth component, mn is the mass of the nth component, and M is the total mass. The dielectric loss tangent of each component may be measured by preparing a resin film of the homopolymer. Df1 <Df2×0.97···(A2) Df2=Df1×m1 / M+···+Dfn×mn / M+···+DfN×(mN / M)···(A3)

[0093] "Storage modulus" The resin film disclosed herein has a storage modulus of 1.0 × 10⁻⁶ at 180°C. 6Preferably Pa or higher, 1.0 × 10 7 It is more preferable that it be Pa or higher, 1.0 × 10 7 ~1.0×10 10 It is most preferable that the storage modulus of the resin film of this disclosure is within the range of Pa. Furthermore, the storage modulus of the resin film of this disclosure is 1 × 10 at 260°C. 5 Preferably Pa or higher, 1.0 × 10 6 It is more preferable that it be Pa or higher, 1.0 × 10 6 Pa~5.0×10 9 It is most preferable that the storage modulus be within the range of Pa. By satisfying the storage modulus at each of the above temperatures, heat resistance suitable for mounting and use in high-temperature environments can be achieved.

[0094] "Glass transition temperature" If the resin film of this disclosure is amorphous and has no melting point, it is preferable that its glass transition temperature (Tg) is 180°C or higher, and more preferably in the range of 180 to 400°C. A Tg of 180°C or higher for the resin film provides heat resistance that enables mounting and use in high-temperature environments.

[0095] The storage modulus and glass transition temperature can be measured by the following method. An evaluation sample is prepared by cutting a film or resin sheet to 5 mm × 20 mm. Next, using a dynamic viscoelastic device (e.g., DMA: T.A. Instruments, product name: RSA-G2), the sample is heated stepwise from 30°C to 500°C at a heating rate of 4°C / min, and measurements are taken at a frequency of 1 Hz. The temperature of the tanδ peak is defined as the glass transition temperature Tg. If multiple tanδ peaks appear, the highest temperature among the multiple peak temperatures is defined as Tg. Here, tanδ refers to the loss coefficient and means the ratio of the loss modulus G'' to the storage modulus G' (G'' / G').

[0096] "Melting point" If the resin film of this disclosure is crystalline and has a melting point, it is preferable that the melting point (Tm) is 260°C or higher, and more preferably in the range of 260 to 450°C. A melting point Tm of 260°C or higher of the resin film provides heat resistance that enables mounting and use in high-temperature environments. The melting point can be measured by the method described above. If multiple peaks appear in the differential scanning calorimeter measurement, the highest temperature among the peak temperatures is taken as the melting point.

[0097] The melting point of a resin can be measured, for example, by a method compliant with JIS K7121:2012. If multiple peaks originating from melting appear, the peak temperature of the highest temperature is taken as the melting point.

[0098] (Tensile modulus of elasticity) The resin film of this disclosure preferably has a tensile modulus of 1.0 GPa or higher. The tensile modulus of the resin film of this disclosure is preferably in the range of 1.5 to 6.0 GPa, and more preferably in the range of 1.5 GPa to 5.0 GPa. If the tensile modulus is less than 1.0 GPa, tack occurs, and it is not possible to obtain a film that is easy to process.

[0099] (Elongation) The elongation of the resin film disclosed herein is preferably 0.1% or more, more preferably 0.5% to 150%, and even more preferably 100% or less. High elongation leads to a deterioration of the CTE of the resin film.

[0100] The tensile modulus and elongation of the resin film can be measured by the following method. For example, a tensile test is performed on a resin film measuring 12.7 mm in width and 127 mm in length using a Strograph R-1 (manufactured by Toyo Seiki Seisakusho Co., Ltd.) at a temperature of 23°C and a relative humidity of 50% RH at a rate of 50 mm / min. From the obtained results, the tensile modulus and elongation of the resin film can be calculated.

[0101] <Metal-clad laminate> The metal-clad laminate of this disclosure comprises a single or multi-layer insulating resin layer and a metal layer laminated on one or both sides of the insulating resin layer, wherein at least one layer of the insulating resin layer is made of the resin film of this disclosure. The metal-clad laminate of this disclosure may also include any other layers.

[0102] There are no particular restrictions on the material of the metal layer, 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, copper or copper alloys are particularly preferred. The material of the wiring layer in the circuit board of this embodiment, which will be described later, is the same as that of the metal layer.

[0103] The thickness of the metal layer is not particularly limited, but when using metal foil such as copper foil, it is preferably 35 μm or less, and more preferably in the range of 5 to 25 μm. From the viewpoint of production stability and handling, it is preferable that the lower limit of the metal foil thickness be 5 μm. When using copper foil, either rolled copper foil or electrolytic copper foil may be used. In addition, commercially available copper foil can be used as the copper foil.

[0104] The surface roughness of the metal layer is not particularly limited, but from the viewpoint of ensuring adhesion with the adhesive layer and achieving both conductivity loss and roughness, it is preferable to have a roughened surface with a maximum height (Rz) in the range of 0.3 to 1.5 μm. Furthermore, the metal foil may be subjected to surface treatments such as rust prevention treatment or improved adhesion using siding, aluminum alkoxide, aluminum chelate, silane coupling agents, etc.

[0105] <Circuit board> The circuit board of this disclosure is formed by wiring a metal layer of a metal-clad laminate of this disclosure. A circuit board such as an FPC can be manufactured by processing one or more metal layers of a metal-clad laminate into a pattern by a conventional method to form a wiring layer (conductor circuit layer). The circuit board may also include a coverlay film that covers the wiring layer.

[0106] <Electronic Devices / Electronic Equipment> The electronic devices and electronic equipment of this disclosure include the circuit boards of this disclosure. Examples of electronic devices of this embodiment include display devices such as liquid crystal displays, organic EL displays, and electronic paper, organic EL lighting, solar cells, touch panels, camera modules, inverters, converters, and their components. Examples of electronic equipment include hard disk drives (HDDs), DVDs, mobile phones, smartphones, tablet terminals, electronic control units (ECUs) and power control units (PCUs) of automobiles. Circuit boards are preferably used in these electronic devices and electronic equipment as components such as wiring for movable parts, cables, and connectors.

[0107] The copolymers, resin compositions containing the copolymers, resin films, metal-clad laminates, circuit boards, electronic devices, and electronic devices of this disclosure have been described in detail above. It should be noted that the technical scope of the present invention is not limited to the embodiments described above, and various modifications can be made without departing from the spirit of the invention. Furthermore, without departing from the spirit of the invention, the components in the embodiments described above can be replaced with well-known components, and the above-described modifications can be combined as appropriate. [Examples]

[0108] The features of the present invention will be explained in more detail below with reference to examples. However, the scope of the present invention is not limited to these examples. In the following examples, unless otherwise specified, various measurements and evaluations are performed as described below.

[0109] "Measurement of weight-average molecular weight (Mw) and number-average molecular weight (Mn)" Weight-average molecular weight and number-average molecular weight were measured using a gel permeation chromatograph (HLC-8420GPC, manufactured by Tosoh Corporation; GPC columns: TSKgel GMHHR-M (manufactured by Tosoh Corporation, 7.8 mm inner diameter x 30 cm length), 2 columns). The sample solution was prepared to have a solid content concentration of 0.1%. The solution was then filtered using a 0.45 μm filter. The resulting filtrate was used as the sample solution for measurement. Polystyrene was used as the standard substance, and tetrahydrofuran (THF), N,N-dimethylacetamide (DMAc), etc., were used as the developing solvent depending on the solubility of the resin. The flow rate was 0.8 mL / min, the measurement temperature was 40°C, and the sample injection volume was 100 μL. The results are shown in Table 2. For Yumex 1010, the catalog value was used.

[0110] "Measuring viscosity" Viscosity was measured at 25°C using an E-type viscometer (Brookfield, product name: DV-II+Pro). The rotation speed was set so that the torque was between 10% and 90%, and the value was read after 2 minutes from the start of measurement, when the viscosity stabilized. The obtained results are shown in Tables 6A and 6B.

[0111] "Measurement of Storage Modulus" The storage modulus was measured using a dynamic viscoelasticity analyzer (DMA: TA Instruments, product name: RSA-G2) on a resin film measuring 5 mm wide x 70 mm long, from 30°C to 500°C at a heating rate of 4°C / min and a frequency of 1 Hz. The peak temperature of the loss coefficient was also determined. The obtained results are shown in Tables 4, 7A, and 7B.

[0112] "Measurement of linear thermal expansion coefficient" Using a Hitachi High-Technologies Corporation (formerly Seiko Instruments Corporation, product name: TMA / 7100) instrument, a sample (3 mm wide x 20 mm long) was heated from 30°C to 180°C at a constant heating rate while applying a 5.0 g load. After holding the sample at this temperature for 10 minutes, it was cooled at a rate of 5°C / min, and the average thermal expansion coefficient (linear thermal expansion coefficient) from 180°C to 100°C was determined. The results are shown in Tables 3, 7A, and 7B.

[0113] "SP value" The SP value (solubility parameter) for each sample was calculated based on the Fedors method described in Non-Patent Document 1. The SP value δ obtained by the Fedors method was calculated from the above formula (A1). Specifically, the cohesive energy and molecular capacity were calculated for each structure constituting the resin, and the SP value and the difference between the SP value of the first structure and the SP value of the remaining structure were obtained by dividing the sum of the cohesive energies of each component by the sum of the molecular capacities and raising the value to the power of 1 / 2. The obtained SP values ​​are shown in Table 4.

[0114] "δP, δH, δP × δH" Furthermore, the δP and δH values ​​for each sample were determined using the Hansen Solubility Parameter in Practice. From the obtained δP and δH values, the product of δP and δH (δP × δH) and the difference between the products of δP and δH were calculated using the method described above. The results are shown in Table 4.

[0115] [Measurement of relative permittivity (Dk) and dielectric loss tangent (Df)] For the samples labeled "SPDR" in the measurement method column of Table 3, and the samples in Tables 7A and 7B, the relative permittivity (Dk) and dielectric loss tangent (Df) of the resin film were measured at a frequency of 10 GHz using a vector network analyzer (Agilent, product name: E8363C) and a split-post dielectric resonator (SPDR resonator). Note that the Dk and Df values ​​during humidity control were measured after leaving the resin film used for measurement for 24 hours under conditions of temperature: 24-26°C and relative humidity: 45-55%. The obtained results are shown in Tables 3, 7A, and 7B. The calculation results and judgment results of the above formula (A2) are also shown in Tables 7A and 7B. A value of ○ was used if the condition Df < additive rule Df * 0.97 was satisfied, and a × was used if it was not satisfied.

[0116] For samples marked as "cavity resonance" in the measurement method column of Table 3, a vector network analyzer (Keysight Technologies, product name: Vector Network Analyzer E8363C) and a relative permittivity measuring device manufactured by Kanto Electronics Applied Development Co., Ltd. using the cavity resonator perturbation method were used. The relative permittivity measurement mode was set to TM020, and the relative permittivity (ε1) and dielectric loss tangent (Tanδ1) of the sample were measured at a frequency of 10 GHz. The sample was in powder form and was filled into a sample tube (inner diameter 1.68 mm, outer diameter 2.28 mm, height 8 cm) for measurement. Measurements were performed under conditions of temperature 24-26°C and humidity 45-55%, after being left for 24 hours, and the measured values ​​were calculated as the average of n=3. The obtained results are shown in Table 3.

[0117] [Measurement of tensile modulus and elongation] Using a Strograph R-1 (manufactured by Toyo Seiki Seisakusho Co., Ltd.), a resin film measuring 12.7 mm in width and 127 mm in length was subjected to a tensile test at 50 mm / min under conditions of 23°C and 50% RH relative humidity, and the tensile modulus and elongation of the resin film were calculated. The results are shown in Tables 4, 7A, and 7B.

[0118] "The mass ratio of the first structure" The mass percentage of the first structure is determined based on the "Method for Determining the First Structure" described above. The first structure is identified, and the remainder is identified as the residual structure. The mass ratio of each structure was determined by calculating the molecular weight of each structure. The results are shown in Tables 6A and 6B. The mass percentages of the imide structure and amide acid structure were calculated using the method described above. The results are shown in Tables 6A and 6B.

[0119] "The mass ratio of carbon atoms to hydrogen atoms, the mass ratio of carbon atoms to hydrogen atoms" For the remaining structures of samples No. 1 to 5, the number of hydrogen atoms and carbon atoms was determined, and the mass of each atom in the remaining structure was calculated by multiplying the number of atoms by the atomic weight of each atom. From the obtained masses of each atom, the mass ratio of carbon atoms to hydrogen atoms (C / H) and the mass percentage (wt%) of the sum of carbon and hydrogen atoms in the remaining structure were determined. In addition, the carbon content (wt%), hydrogen content (wt%), oxygen content (wt%), and nitrogen content (wt%) in the remaining structure were determined. The obtained results are shown in Table 2.

[0120] The abbreviations used in the examples and comparative examples refer to the following compounds. XIRAN 6000: Styrene-maleic anhydride copolymer (Tomoe Industrial Co., Ltd., Styrene:maleic acid ratio = 6:1, Weight-average molecular weight (Mw): 10000) XIRAN 1000: Styrene-maleic anhydride copolymer (Tomoe Industrial Co., Ltd., Styrene:maleic acid ratio = 1:1, Weight-average molecular weight (Mw): 10000) FG1901: Maleic anhydride (MA) modified styrene-ethylene-butylene-styrene block copolymer (Kraton copolymer, weight-average molecular weight (Mw): 68000) FG1924: Maleic anhydride (MA) modified styrene-ethylene-butylene-styrene block copolymer (Kraton copolymer, weight-average molecular weight (Mw): 170,000) Yumex 1010: Acid-modified polypropylene (Sanyo Chemical Industries, Ltd., weight-average molecular weight (Mw): 30000) m-TB: 2,2'-dimethyl-4,4'-diaminobiphenyl BP-TME: p-biphenylenebis(trimellitic acid monoester anhydride), CAS number 10340-81-5) BPDA: 3,3',4,4'-biphenyltetracarboxylic acid dianhydride 26DHN-TME:2,6-Naphthalenebis(trimellitic acid monoester anhydride) BAPP: 2,2-Bis[4-(4-aminophenoxy)phenyl]propane ODPA: Oxydiphthalic anhydride TPE-R: 1,3-bis(3-aminophenoxy)benzene PMDA: Pyromellitic anhydride p-PDA: p-phenylenediamine NMP:N-methyl-2-pyrrolidone DMAc: N,N-dimethylacetamide Xylene: (a mixture of ortho-, meta-, and para-xylene isomers)

[0121] (Synthesis Example 1) <Synthesis of copolymers> (Resin composition 1A) In a 500 mL separable flask, 8.00 g of XIRAN 6000 and 160 g of NMP were added and stirred under a nitrogen stream to dissolve the XIRAN 6000. Next, 22.5299 g of BP-TME was added, followed by 9.4701 g of m-TB and 200 g of NMP. The polymerization reaction was carried out by continuing to stir at room temperature for 24 hours to prepare resin composition No. 1A (solid content concentration: 10%, viscosity: 21,634 cP).

[0122] Resin compositions 2A to 17A were prepared in the same manner as resin composition No. 1A, except for the raw material composition shown in Table 5A.

[0123] <Preparation of single-sided copper-clad laminate> A resin composition was uniformly applied to a copper foil (electrolytic copper foil, thickness: 12 μm, resin-side roughness Rzjis: 0.6 μm) so that the thickness after curing would be 25 μm. The resin was then heated and dried at 100-120°C for 10 minutes to remove the solvent. Furthermore, heat treatment was performed from room temperature to 320°C at a heating rate of 5°C / min to complete the imidization process and prepare a single-sided copper-clad laminate.

[0124] <Preparation of resin film> The copper foil of a single-sided copper-clad laminate was etched off using an aqueous ferric chloride solution to obtain the resin film of the example. The results of various evaluations of the resin film are shown in Table 7A.

[0125] Table 7A shows that for resin films No. 2B to 16B, the first structure and the remaining structure satisfied the specified conditions, resulting in resin films with a CTE of 50.0 ppm / K or less and a dielectric loss tangent of 0.0030 or less.

[0126] (Reference example 1) (Resin composition No.17A) Under a nitrogen atmosphere, 30.0 g of XIRAN 6000 and 70.0 g of xylene were added to a 300 mL separable flask to achieve a solid content concentration of 30% by mass, and the mixture was stirred to prepare resin composition No. 17A.

[0127] (Reference example 2) (Resin composition No.18A) 8.8782 g of m-TB and 120 g of NMP were added to a 500 mL separable flask, and the mixture was stirred to dissolve the m-TB. Then, 21.1218 g of BP-TME and 50 g of NMP were added, and the polymerization reaction was carried out by stirring at room temperature for 24 hours to prepare resin composition No. 18A (solids content: 15%, viscosity: 10,453 cP).

[0128] (Reference examples 3~5) (Resin composition No.19A~21A) Resin compositions No. 19A to 21A were prepared in the same manner as resin composition No. 1A, except that the raw material compositions were as shown in Table 5B.

[0129] Table 7B shows the results of measuring various physical properties of single-sided copper-clad laminates and resin films prepared in the same manner as resin composition No. 1A for resin compositions No. 17A to 21A.

[0130] Table 7B shows that resin film No. 17B lacks a primary structure, resulting in a low elastic modulus and making it difficult to form into a film.

[0131] Table 7B shows that resin film No. 18B does not have a residual structure, and therefore the effect of reducing Df with respect to the additive law was not observed.

[0132] Table 7B shows that in resin film No. 19B, the mass ratio of the sum of carbon atoms and hydrogen atoms was less than 77 wt%, so the effect of reducing Df against the additive law did not occur.

[0133] Table 7B shows that in resin films No. 20B and 21B, the proportions of the first structure and the remaining structure were not as specified, making it impossible to achieve both a low CTE and a low dielectric loss tangent.

[0134] The effects of the present invention are obtained based on the structure of the first structure and the atomic ratio in the remaining structure. Therefore, it is believed that by replacing the first structure (polyimide structure) adopted in this embodiment with another structure, desired results can be obtained based on the properties of the replaced structure.

[0135] Although embodiments of the present invention have been described in detail above for illustrative purposes, the present invention is not limited to the above embodiments and various modifications are possible.

[0136] [Table 1]

[0137] [Table 2]

[0138] [Table 3]

[0139] [Table 4]

[0140] [Table 5A]

[0141] [Table 5B]

[0142] [Table 6A]

[0143] [Table 6B]

[0144] [Table 7A]

[0145] [Table 7B] [Industrial applicability]

[0146] The copolymer according to this embodiment possesses both a low CTE and a low dielectric loss tangent, making it highly applicable to industrial use.

Claims

1. A copolymer comprising a first structure containing two or more aromatic rings and a remainder structure, The first structure is a structure in which the aromatic rings are linked to each other by single bonds or linking groups, In the remaining structure, the mass ratio of the sum of carbon atoms and hydrogen atoms to the total mass of the remaining structure is 77 wt% or more. The mass ratio of carbon atoms to hydrogen atoms in the remaining structure is 6.5 or more and 12.5 or less. The mass ratio of the first structure to the total mass of the copolymer is 15 wt% or more and 85 wt% or less. A copolymer in which the number of atoms directly interposed in the bond between the aromatic rings in the linking group is 2 or less.

2. The copolymer according to claim 1, wherein the first structure has a total mass ratio of 15.5 wt% or more of the imide structure and the amide acid structure relative to the total mass of the first structure.

3. The copolymer according to claim 1, wherein the remaining structure has a chain-like hydrocarbon structure in which six or more carbon atoms are bonded to each other by single bonds.

4. The difference in SP values ​​between the first structure and the remaining structure is 3 (J / cm²). ３ ) １／２ More than 10 (J / cm ３ ) １／２ The copolymer according to claim 1, which is as follows:

5. The difference between the product of δP and δH in the HSP values ​​of the first structure and the remaining structure is 50 (J / cm²). ３ ) or more 120 (J / cm ３ The copolymer according to claim 1, wherein the copolymer is as follows:

6. The copolymer according to claim 1, wherein the copolymer is at least one of a block copolymer and a graft copolymer.

7. The copolymer according to claim 1, wherein the mass ratio of the first structure to the remaining structure is 15:85 to 85:

15.

8. The copolymer according to claim 1, wherein the sum of the mass of the carbon atoms and the hydrogen atoms is 90 wt% or more, and the mass ratio of the carbon atoms to the hydrogen atoms is 6.5 or more and 12.5 or less.

9. A resin composition comprising the copolymer described in claim 1.

10. A resin film comprising the copolymer described in claim 1.

11. When measured by a split-post dielectric resonator (SPDR) in an environment with a temperature of 24 to 26°C and a relative humidity of 45 to 55%, the dielectric loss tangent Df1 of the copolymer at 10 GHz and the second dielectric loss tangent Df2 calculated based on two or more repeating units constituting the copolymer satisfy the following equation (1): The resin film according to claim 10, wherein the second dielectric loss tangent is calculated from the additive law based on the dielectric loss tangent of the homopolymer of the repeating units at 10 GHz and the mass ratio of the repeating units. Df1<Df2×0.97...(1)

12. The resin film according to claim 10, wherein the linear thermal expansion coefficient at 180 to 100°C is 50 ppm / K or less.

13. 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 in which at least one of the insulating resin layers is made of the resin film described in claim 10.

14. 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 the resin film described in claim 10.

15. An electronic device comprising the circuit board described in claim 14.

16. An electronic device comprising the circuit board described in claim 14.

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