JP2023027753A - Copolymer and resin composition - Google Patents

Abstract

To provide a copolymer having excellent solvent solubility and low dielectric loss tangent.SOLUTION: This copolymer includes: an aromatic vinyl monomer unit; a crosslinkable group-containing monomer unit; and a monomer unit which gives a homopolymer having a glass transition temperature of 150°C or higher.SELECTED DRAWING: None

Description

The present disclosure relates to copolymers and resin compositions.

In recent years, electrical equipment, electronic equipment, and communication equipment have developed remarkably. These devices now tend to use higher frequencies. Various printed circuit boards are usually used in these devices. Therefore, the printed circuit board is also required to have excellent electrical characteristics corresponding to frequencies in the high frequency band and excellent heat resistance to withstand soldering work.

For example, Patent Document 1 discloses an invention relating to a composition containing a predetermined fluorine-containing thermosetting resin, a siloxane compound, and a hydrosilylation reaction catalyst. However, what is specifically disclosed as fluorine-containing thermosetting resins is nothing more than those obtained by introducing cross-linking groups into OH group-containing fluorine resins by polymer reaction.

Patent Literature 2 discloses an invention relating to a given laminate, and describes introducing a cross-linking group using a fluorine-containing thermosetting resin. However, it is only described that a cross-linking group is introduced into an OH group-containing fluororesin by a polymer reaction.

Patent Document 3 discloses an invention relating to a specific curable resin composition comprising a fluoropolymer and a hydrosilylation cross-linking agent, and describes examples of dicyclopentadiene and fluoroolefin. However, it cannot be said that the polymerization efficiency is good. Further, although a curing system using a cross-linking agent is disclosed, a curing reaction by heat alone is not disclosed.

WO2008/044765 JP 2014-26619 A WO2011/115042

The present disclosure provides a copolymer excellent in solvent solubility and low dielectric loss tangent.

The present disclosure (1) relates to a copolymer comprising an aromatic vinyl monomer unit, a cross-linking group-containing monomer unit, and a monomer unit giving a homopolymer having a glass transition temperature of 150° C. or higher.

The present disclosure (2) is the copolymer of the present disclosure (1) which is a thermosetting resin.

(3) of the present disclosure is the copolymer of (1) or (2) of the present disclosure, wherein the aromatic vinyl monomer units are styrene units.

The present disclosure (4) is a copolymer of any combination with any of the present disclosures (1) to (3), wherein the cross-linking group-containing monomer unit includes a diene monomer unit having an alicyclic structure.

The present disclosure (5) is a copolymer of any combination with any of the present disclosures (1) to (3), wherein the cross-linking group-containing monomer unit includes a monomer unit having a dicyclopentenyl structure.

The present disclosure (6) is any of the present disclosure (1) to (3), wherein the crosslinking group-containing monomer unit contains at least one selected from the group consisting of dicyclopentadiene units and dicyclopentenyl vinyl ether units. It is a copolymer of a combination of

The present disclosure (7) is a copolymer of any combination with any of the present disclosures (1) to (6), wherein the monomer units that provide the homopolymer having a glass transition temperature of 150° C. or higher include maleimide units. .

The present disclosure (8) is the copolymer of the present disclosure (7), wherein the maleimide units include at least one selected from the group consisting of N-cyclohexylmaleimide units and N-phenylmaleimide units.

The present disclosure (9) is a copolymer of any combination with any of the present disclosures (1) to (8), further comprising a fluorine-containing monomer unit providing a C—F bond to the main chain.

(10) of the present disclosure is a copolymer of any combination with any of (1) to (9) of the present disclosure having a glass transition temperature of 140° C. or higher.

(11) of the present disclosure is a copolymer of any combination with any of (2) to (10) of the present disclosure having a heat curing temperature of 240° C. or lower.

Disclosure (12) is a copolymer of any combination with any of Disclosures (1)-(11) having solubility in methyl ethyl ketone or toluene.

The present disclosure (13) is any combination with any of the present disclosure (1) to (12), wherein the crosslinking group-containing monomer unit is 1 mol% or more with respect to the total polymerized units constituting the copolymer. It is a copolymer.

The present disclosure (14) is the present disclosure (1) to (13), wherein the monomer unit that provides the homopolymer having a glass transition temperature of 150 ° C. or higher is 5 mol% or more with respect to the total polymer units constituting the copolymer. ) in any combination.

Disclosure (15) is a copolymer of any combination with any of Disclosures (1) to (14) having a dielectric loss tangent of 0.0030 or less.

Disclosure (16) relates to a copolymer composition comprising a copolymer of any combination of any of the disclosures (1)-(15) and a solvent.

The present disclosure (17) is the copolymer composition of the present disclosure (16), wherein the copolymer composition contains a polymer containing a plurality of vinyl groups or a monomer component containing a plurality of vinyl groups.

This disclosure (18) is the copolymer composition of this disclosure (16) or (17) containing a photoinitiator.

Disclosure (19) is a copolymer composition of any combination with any of Disclosures (16) to (18) having a gel fraction of 30% or more.

This disclosure (20) relates to a film comprising a copolymer in any combination with any of this disclosure (1)-(15).

The present disclosure (21) is a laminate comprising a substrate and a resin layer provided on the substrate, wherein the resin layer is any of the present disclosure (1) to (15). It relates to laminates comprising combinatorial copolymers.

The present disclosure (22) is a metal-clad laminate comprising a metal foil and a resin layer provided on the metal foil, wherein the resin layer is any of the present disclosure (1) to (15). The present invention relates to a metal-clad laminate containing any combination of copolymers.

The present disclosure (23) relates to a printed circuit board characterized by comprising a pattern circuit formed by etching the metal foil of the metal-clad laminate of the present disclosure (22).

According to the present disclosure, a copolymer excellent in solvent solubility and low dielectric loss tangent can be provided.

As described in Patent Documents 1 and 2, it is generally necessary to introduce a cross-linking group in order to convert a resin (polymer) into a thermosetting resin. Conventionally, cross-linking groups are generally introduced by synthesizing a polymer containing OH groups and introducing acrylic groups through a polymer reaction. In particular, acrylic monomers having isocyanate are reacted with OH groups to introduce them. The method is simple and widely used. However, resins having acrylic groups as cross-linking groups are not so good in electrical properties. As another technique, there is a method of simply copolymerizing a diene monomer at the time of polymerization, but there are problems such as gelation during polymerization and the introduction amount of cross-linking groups being limited.

As a result of intensive studies by the present disclosure, by using a copolymer (resin) of the aromatic vinyl monomer of the present disclosure, a crosslinking group-containing monomer, and a monomer that gives a homopolymer having a glass transition temperature of 150 ° C. or higher, solvent-soluble , found that a copolymer excellent in low dielectric loss tangent can be provided, leading to completion.

The copolymer (resin) of the present disclosure has aromatic vinyl monomer units, crosslinking group-containing monomer units, and monomer units that provide a homopolymer having a glass transition temperature of 150° C. or higher. By having these three types of units, the above copolymer is endowed with a very low dielectric loss tangent and is excellent in solvent solubility. Also, the dielectric constant and linear expansion coefficient are low. Furthermore, since the cross-linking group-containing monomer unit is introduced, self-crosslinking (thermal cross-linking, etc.) is possible even when a cross-linking agent is not used, and good thermosetting properties can be imparted.

The copolymers of the present disclosure have aromatic vinyl monomer units.
An "aromatic vinyl monomer unit" is a polymerized unit based on an aromatic vinyl monomer. The above copolymer may contain one type of aromatic vinyl monomer unit, or may contain two or more types of aromatic vinyl monomer units. The aromatic vinyl monomer units may be either fluorine-containing monomer units (polymerized units based on fluorine-containing monomers) or fluorine-free monomer units (polymerized units based on fluorine-free monomers).

The aromatic vinyl monomer is a monomer containing an aromatic ring and a vinyl group in the molecule, and examples thereof include styrene, α-methylstyrene, p-methylstyrene, o-methylstyrene, t-butylstyrene and the like. . Among the above aromatic vinyl monomer units, styrene units are preferred from the viewpoint of low dielectric constant and low dielectric loss tangent.

Since the aromatic vinyl monomer unit is excellent in low dielectric constant and low dielectric loss tangent, it is preferably 5 mol% or more, more preferably 20 mol% or more, relative to the total polymer units constituting the copolymer. , more preferably 30 mol % or more, preferably 90 mol % or less, more preferably 80 mol % or less, and even more preferably 70 mol % or less.

The copolymers of the present disclosure have cross-linking group-containing monomer units.
A “crosslinking group-containing monomer unit” is a polymerized unit based on a crosslinkable group-containing monomer (a monomer having a crosslinkable group). The above copolymer may contain one type of cross-linking group-containing monomer unit, or may contain two or more types. The cross-linking group-containing monomer unit may be either a fluorine-containing monomer unit or a non-fluorine-containing monomer unit.

The above-mentioned cross-linking group-containing monomer has a cross-linking group (a group having cross-linking properties) in its molecule. Examples of cross-linking groups include groups containing carbon-carbon double bonds, halogen atoms, acid anhydride groups, carboxy groups, amino groups, cyano groups, hydroxyl groups and the like.

The cross-linking group-containing monomer unit is preferably 1 mol% or more, more preferably 3 mol% or more, relative to the total polymer units constituting the copolymer because it is excellent in low dielectric constant and low dielectric loss tangent. , more preferably 5 mol % or more, preferably 50 mol % or less, more preferably 30 mol % or less, and even more preferably 20 mol % or less.

The above-mentioned cross-linking group-containing monomer unit is not particularly limited as long as it is a monomer unit having a cross-linking group. Polymerized units based on monomers) are preferred.

Examples of the diene monomer having an alicyclic structure include monocyclic alicyclic dienes, polycyclic alicyclic condensed dienes, and bridged ring dienes. Monocyclic alicyclic dienes include 1,4-cyclohexadiene, 1,5-cyclooctadiene, 1,5-cyclododecadiene, 4-vinylcyclohexene, 1-allyl-4-isopropylidenecyclohexane, 3-allyl cyclopentene, 1-isopropenyl-4-(4-butenyl)cyclohexane, limonene and the like. Polycyclic alicyclic condensed dienes and bridged ring dienes include tetrahydroindene, methyltetrahydroindene, dicyclopentadiene, bicyclo(2,2,1)hepta-2,5-diene, 2-methylbicycloheptadiene, alkenyl, alkylidene, cycloalkenyl and cycloalkylidene norbornene (5-methylene-2-norbornene, 5-ethylidene-2-norbornene, 5-isopropylidene norbornene, 5-(4-cyclopentenyl)-2-norbornene, 5-cyclohexyl) den-2-norbornene, etc.). Among them, limonene, dicyclopentadiene, and 5-ethylidene-2-norbornene are preferred.

From the viewpoint of low dielectric constant and low dielectric loss tangent, the above-mentioned crosslinking group-containing monomer units include dicyclopentadiene units (polymerized units based on dicyclopentadiene) and monomer units having a dicyclopentenyl structure (monomers having a dicyclopentenyl structure Polymerized units based on) are also preferred. Among them, a monomer unit having a dicyclopentenyl structure is more preferable. Here, the monomer unit having a dicyclopentenyl structure preferably contains 0 to 1 heteroatoms.

Among the crosslinking group-containing monomer units, at least one selected from the group consisting of dicyclopentadiene units and dicyclopentenyl vinyl ether units is desirable.

The above dicyclopentadiene (DCPD) is a monomer represented by the following formula.

Since the dicyclopentadiene unit is excellent in low dielectric constant and low dielectric loss tangent, it is preferably 1 mol% or more, more preferably 3 mol% or more, based on the total polymer units constituting the copolymer. 5 mol% or more is more preferable, 50 mol% or less is preferable, 30 mol% or less is more preferable, and 20 mol% or less is still more preferable.

Examples of the monomer containing the dicyclopentenyl structure include monomers having a dicyclopentenyl group represented by the following formulas (I-1) and (I-2).

（式中、Ｒ^５１は、水素原子又はメチル基である。） Examples of the monomer having a dicyclopentenyl group represented by the above formulas (I-1) and (I-2) include the following compounds.

(In the formula, R ⁵¹ is a hydrogen atom or a methyl group.)

Among them, compounds represented by the following formulas are preferable.

Specific examples of the dicyclopentenyl group-containing monomer represented by formulas (I-1) and (I-2) include dicyclopentenyl acrylate and dicyclopentenyl methacrylate.

（式中、Ｒ^６１は、水素原子又はメチル基である。） Examples of the dicyclopentenyl group-containing monomer represented by formulas (I-1) and (I-2) include the following compounds.

(Wherein, R ⁶¹ is a hydrogen atom or a methyl group.)

Among them, compounds represented by the following formulas are preferable.

Specific examples of the dicyclopentenyl group-containing monomer represented by formulas (I-1) and (I-2) include dicyclopentenyl vinyl ether.

Since the monomer unit containing the dicyclopentenyl structure is excellent in low dielectric constant and low dielectric loss tangent, it is preferably 1 mol% or more, 3 mol% or more with respect to the total polymer units constituting the copolymer. is more preferably 5 mol % or more, preferably 50 mol % or less, more preferably 30 mol % or less, and even more preferably 20 mol % or less.

The copolymer of the present disclosure has monomer units that give the homopolymer having a glass transition temperature (Tg) of 150° C. or higher (polymerized units based on a monomer that gives a homopolymer having a Tg of 150° C. or higher). "A monomer unit that gives a homopolymer having a glass transition temperature of 150°C or higher" means a monomer having a glass transition temperature of 150°C or higher when a homopolymer obtained by polymerizing only monomers of the same type, It is a polymerized unit based on. The above copolymer may contain one type of such monomer units, or may contain two or more types of such monomer units. The monomer units may be fluorine-containing monomer units or fluorine-free monomer units.

In the monomer unit that provides a homopolymer having a glass transition temperature (Tg) of 150° C. or higher, the Tg is preferably 170° C. or higher, more preferably 200° C. or higher, and still more preferably 250° C. or higher. It is 400° C. or lower, more preferably 350° C. or lower, still more preferably 320° C. or lower.
The above Tg is a value obtained by measuring with a differential scanning calorimeter (DSC).

The monomer unit that gives the homopolymer having a glass transition temperature of 150° C. or higher is excellent in low dielectric constant and low dielectric loss tangent, so it is preferable that it is 5 mol % or more with respect to the total polymer units constituting the copolymer. It is preferably 20 mol % or more, more preferably 30 mol % or more, preferably 80 mol % or less, more preferably 70 mol % or less, and still more preferably 60 mol % or less.

The monomer unit that provides the homopolymer having a glass transition temperature of 150° C. or higher preferably contains a maleimide unit (a monomer unit based on a maleimide) because of its excellent low dielectric constant and low dielectric loss tangent, and N-substituted It more preferably contains maleimide units (monomeric units based on N-substituted maleimides). Among others, it is desirable to contain monomer units represented by the following formulas (II-1) and (II-2).

（式中、Ｒ^１１は、炭素数７～１４のアリールアルキル基、又は炭素数６～１４のアリール基である。Ｒ^１２及びＲ^１３は、それぞれ独立に、水素原子、酸素原子、硫黄原子、炭素数１～１２のアルキル基、又は炭素数６～１４のアリール基である。なお、Ｒ^１１、Ｒ^１２、Ｒ^１３は、置換基を有してもよい。）

(In the formula, R ¹¹ is an arylalkyl group having 7 to 14 carbon atoms or an aryl group having 6 to 14 carbon atoms; R ¹² and R ¹³ each independently represent a hydrogen atom, an oxygen atom, a sulfur atom, an alkyl group having 1 to 12 carbon atoms or an aryl group having 6 to 14 carbon atoms (R ¹¹ , R ¹² and R ¹³ may have substituents).

（式中、Ｒ^１４は、水素原子、炭素数３～１２のシクロアルキル基、又は炭素数１～１２のアルキル基である。Ｒ^１５及びＲ^１６は、それぞれ独立に、水素原子、酸素原子、硫黄原子、炭素数１～１２のアルキル基、又は炭素数６～１４のアリール基である。なお、Ｒ^１４、Ｒ^１５、Ｒ^１６は、置換基を有してもよい。）

(In the formula, R ¹⁴ is a hydrogen atom, a cycloalkyl group having 3 to 12 carbon atoms, or an alkyl group having 1 to 12 carbon atoms. R ¹⁵ and R ¹⁶ each independently represent a hydrogen atom, an oxygen atom, a sulfur atom, an alkyl group having 1 to 12 carbon atoms, or an aryl group having 6 to 14 carbon atoms, and R ¹⁴ , R ¹⁵ and R ¹⁶ may have a substituent.)

Examples of substituents for R ¹¹ to R ¹⁶ in formulas (II-1) and (II-2) above include a halogen atom, an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, a nitro group, and benzyl. and the like.

Examples of the monomer forming the monomer unit represented by the above formula (II-1) include N-arylmaleimides, N-aromatic substituted maleimides and the like. Specifically, N-phenylmaleimide, N-benzylmaleimide, N-(2-chlorophenyl)maleimide, N-(4-chlorophenyl)maleimide, N-(4-bromophenyl)maleimide, N-(2-methylphenyl ) maleimide, N-(2,6-dimethylphenyl)maleimide, N-(2-ethylphenyl)maleimide, N-(2-methoxyphenyl)maleimide, N-(2-nitrophenyl)maleimide, N-(2, 4,6-trimethylphenyl)maleimide, N-(4-benzylphenyl)maleimide, N-(2,4,6-tribromophenyl)maleimide, N-naphthylmaleimide, N-anthracenylmaleimide, 3-methyl- 1-phenyl-1H-pyrrole-2,5-dione, 3,4-dimethyl-1-phenyl-1H-pyrrole-2,5-dione, 1,3-diphenyl-1H-pyrrole-2,5-dione, 1,3,4-triphenyl-1H-pyrrole-2,5-dione and the like. Among them, N-phenylmaleimide and N-benzylmaleimide are preferred, and N-phenylmaleimide is more preferred, from the viewpoint of low dielectric constant and low dielectric loss tangent.

Since the monomer unit represented by the formula (II-1) is excellent in low dielectric constant and low dielectric loss tangent, it is preferably 5 mol% or more with respect to the total polymer units constituting the copolymer. mol % or more is more preferable, 30 mol % or more is more preferable, 80 mol % or less is preferable, 70 mol % or less is more preferable, and 60 mol % or less is even more preferable.

Examples of the monomer forming the monomer unit represented by the above formula (II-2) include N-methylmaleimide, N-ethylmaleimide, Nn-propylmaleimide, N-isopropylmaleimide, Nn-butylmaleimide, N-isobutylmaleimide, Ns-butylmaleimide, Nt-butylmaleimide, Nn-pentylmaleimide, Nn-hexylmaleimide, Nn-heptylmaleimide, Nn-octylmaleimide, N-lauryl Maleimide, N-2-ethylhexylmaleimide, N-cyclopentylmaleimide, N-cyclohexylmaleimide, N-cyclohexylmethylmaleimide, 1-cyclohexyl-3-methyl-1H-pyrrole-2,5-dione, 1-cyclohexyl-3,4 -dimethyl-1H-pyrrole-2,5-dione, 1-cyclohexyl-3-phenyl-1H-pyrrole-2,5-dione, 1-cyclohexyl-3,4-diphenyl-1H-pyrrole-2,5-dione etc. Among them, N-methylmaleimide, N-ethylmaleimide, N-isopropylmaleimide and N-cyclohexylmaleimide are preferred, and N-cyclohexylmaleimide is more preferred, from the viewpoint of low dielectric constant and low dielectric loss tangent.

Since the monomer unit represented by the above formula (II-2) is excellent in low dielectric constant and low dielectric loss tangent, it is preferably 5 mol% or more with respect to the total polymer units constituting the copolymer. mol % or more is more preferable, 30 mol % or more is more preferable, 80 mol % or less is preferable, 70 mol % or less is more preferable, and 60 mol % or less is even more preferable.

Since the total unit amount of the monomer units represented by the above formulas (II-1) and (II-2) is excellent in low dielectric constant and low dielectric loss tangent, 5 It is preferably at least 20 mol%, more preferably at least 30 mol%, preferably at most 80 mol%, more preferably at most 70 mol%, and even more preferably at most 60 mol%.

The maleimide units preferably include at least one selected from the group consisting of N-cyclohexylmaleimide units and N-phenylmaleimide units.

From the viewpoint of low dielectric constant and low dielectric loss tangent, the copolymer of the present disclosure preferably has a molar ratio of aromatic vinyl monomer units/crosslinking group-containing monomer units of (50 to 95)/(5 to 50). , (55-95)/(5-45), more preferably (60-95)/(5-40).

From the viewpoint of low dielectric constant and low dielectric loss tangent, the copolymer of the present disclosure has a monomer unit/crosslinking group-containing monomer unit molar ratio that gives a homopolymer having a glass transition temperature of 150 ° C. or higher (50 to 95) / ( 5 to 50), more preferably (60 to 90)/(10 to 40), and even more preferably (65 to 90)/(10 to 35).

In the copolymer, the total content of the aromatic vinyl monomer units, the crosslinking group-containing monomer units, and the monomer units that provide a homopolymer having a glass transition temperature of 150° C. or higher is , preferably 70 mol % or more, more preferably 80 mol % or more, still more preferably 90 mol % or more, even more preferably 95 mol % or more, and particularly preferably 97 mol % or more. It may be 100 mol % with respect to all polymerized units.

From the viewpoint of low dielectric constant and low dielectric loss tangent, the copolymer of the present disclosure further has a fluorine-containing monomer unit (hereinafter simply referred to as "fluorine-containing monomer unit") that provides a C—F bond to the main chain. is preferred. In this case, the copolymer contains fluorine atoms and has C—F bonds between the carbon atoms forming the main chain and the fluorine atoms.

The fluorine-containing monomer unit (polymerized unit based on the fluorine-containing monomer) can be introduced into the copolymer by using the fluorine-containing monomer. The fluorine-containing monomer may be either a cyclic monomer or an acyclic monomer. Cyclic monomers and non-cyclic monomers preferably have a C—F bond between the carbon atoms and fluorine atoms forming the main chain of the copolymer.

Examples of the fluorine-containing monomer include fluorine-containing vinyl monomers, fluorine-containing acrylic monomers, fluorine-containing styrene monomers, hydrogen-containing fluoroolefins, and fluorine-containing norbornene. Among them, fluorine-containing vinyl monomers and fluorine-containing acrylic monomers are preferable.

The fluorine-containing vinyl monomer is at least one selected from the group consisting of tetrafluoroethylene [TFE], chlorotrifluoroethylene [CTFE], hexafluoropropylene [HFP] and perfluoro(alkyl vinyl ether). is preferred, and at least one selected from the group consisting of TFE, CTFE, HFP and perfluoro(alkyl vinyl ether) is more preferred. Low dielectric constant and low dielectric loss tangent, excellent dispersibility, moisture resistance, heat resistance, flame retardancy, adhesion, and chemical resistance. It is more preferably at least one selected from the group consisting of TFE, CTFE and HFP in terms of excellent resistance and moisture resistance, and is selected from the group consisting of TFE and HFP in terms of not containing chlorine. At least one type is more preferable, and TFE is particularly preferable in terms of excellent copolymerizability.
Examples of the perfluoro(alkyl vinyl ether) include perfluoro(methyl vinyl ether) [PMVE], perfluoro(ethyl vinyl ether) [PEVE], perfluoro(propyl vinyl ether) [PPVE], perfluoro(butyl vinyl ether), and the like. are not limited to these.

Among the fluorine-containing vinyl monomers, fluorine-containing ethylene, fluorine-containing propylene, and fluorine-containing vinyl ether are preferable, and tetrafluoroethylene, chlorotrifluoroethylene, hexafluoropropylene, and perfluoro(alkyl vinyl ether) are more preferable.

（式中、Ｒ^７１～Ｒ^７４は、互いに独立して、１価の基であり、Ｒ^７１～Ｒ^７３の少なくとも１つがフッ素原子又はＣＦ_３基である。） In particular, fluorine-containing vinyl monomers represented by the following formula are suitable.

(In the formula, R ⁷¹ to R ⁷⁴ are each independently a monovalent group, and at least one of R ⁷¹ to R ⁷³ is a fluorine atom or a CF ₃ group.)

The monovalent groups of R ⁷¹ to R ⁷⁴ include, for example, hydrogen atoms, halogen atoms (fluorine atom, chlorine atom, etc.), monovalent hydrocarbon groups and the like.
The above monovalent hydrocarbon group may have a heteroatom such as a nitrogen atom or an oxygen atom. The above monovalent hydrocarbon group may be linear, branched or cyclic. The number of carbon atoms in the monovalent hydrocarbon group is preferably 1-8, more preferably 1-5, still more preferably 1-3. Examples of the monovalent hydrocarbon group include alkyl groups, alkenyl groups, and alkynyl groups having the number of carbon atoms described above.
The monovalent group is preferably a hydrogen atom, a fluorine atom, a chlorine atom, a fluorinated alkyl group having the above carbon number, or a fluorinated alkoxy group having the above carbon number.

（式中、Ｒ^４１は、１個以上のフッ素原子で置換されてもよいアルキル基を表す。） Examples of the fluorine-containing acrylic monomer include compounds represented by the following formula, since they can introduce a C—F bond into the main chain of the polymer and increase the glass transition temperature of the polymer.

(In the formula, ^R41 represents an alkyl group optionally substituted with one or more fluorine atoms.)

（式中、Ｒ^４２は、１個以上のフッ素原子で置換されてもよいアルキル基を表す。）

(In the formula, ^R42 represents an alkyl group optionally substituted with one or more fluorine atoms.)

Examples of the alkyl group of the “alkyl group optionally substituted with one or more fluorine atoms” represented by R ⁴¹ and R ⁴² include methyl group, ethyl group, propyl group and butyl group. Among them, a methyl group, an ethyl group and a t-butyl group are preferable, and a methyl group is more preferable.

In particular, fluorine-containing acrylic monomers represented by the following formula are suitable.

Specific examples of the fluorine-containing acrylic monomer represented by the above formula include methyl-2-fluoroacrylate and ethyl-2-fluoroacrylate.

Examples of the fluorine-containing acrylic monomer include monomers represented by the following formulas (monomers having a dicyclopentenyl group represented by formulas (I-1) and (I-2) above). For example, by using these monomers, dicyclopentenyl groups represented by the above formulas (I-1) and (I-2) can be introduced into the copolymer.

As the fluorine-containing styrene monomer, CF ₂ =CF--C ₆ H ₅ and CF ₂ =CF--C ₆ H ₄ can be used in that a CF bond can be introduced into the polymer main chain and the glass transition temperature of the polymer can be increased. At least one selected from the group consisting of —CH ₃ and CF ₂ =CF—C ₆ H ₄ —CF ₃ is preferable, and fluorine-containing styrene monomers represented by the following formulas are particularly preferable.

As the above-mentioned hydrogen-containing fluoroolefin, those in which the hydrogen atoms of ethylene are replaced with fluorine atoms are preferable, and vinyl fluoride, trifluoroethylene, vinylidene fluoride [VDF] and the like can be mentioned. Among them, vinyl fluoride is preferred.

The fluorine-containing norbornene may have a polymerizable group, and may have one norbornene skeleton or a plurality of norbornene skeletons. A fluorine-containing norbornene is produced by a Diels-Alder addition reaction between an unsaturated compound and a diene compound.

Examples of the unsaturated compound include fluorine-containing olefin, fluorine-containing allyl alcohol, fluorine-containing homoallyl alcohol, α-fluoroacrylic acid, α-trifluoromethyl acrylic acid, fluorine-containing acrylic acid ester or fluorine-containing methacrylic acid ester, 2- (benzoyloxy)pentafluoropropane, 2-(methoxyethoxymethyloxy)pentafluoropropene, 2-(tetrahydroxypyranyloxy)pentafluoropropene, 2-(benzoyloxy)trifluoroethylene, 2-(methoxymethyloxy) Examples include trifluoroethylene.
Examples of the diene compound include cyclopentadiene and cyclohexadiene.

Examples of the fluorine-containing norbornene include compounds represented by the following formulas.

Among the fluorine-containing monomers described above, the fluorine-containing monomer preferably contains at least one selected from the group consisting of fluorine-containing ethylene, fluorine-containing propylene, and fluorine-containing vinyl ether, vinylidene fluoride, tetrafluoroethylene, More preferably, it contains at least one selected from the group consisting of chlorotrifluoroethylene, vinyl fluoride, hexafluoropropylene, and perfluoro(alkyl vinyl ether).

Moreover, the fluorine-containing monomer preferably contains at least one of a compound represented by the following formula, tetrafluoroethylene, and hexafluoropropylene.

Furthermore, the fluorine-containing monomer preferably contains at least one compound represented by the following formula.

When the polymer contains the fluorine-containing monomer unit, the fluorine-containing monomer unit is excellent in low dielectric constant and low dielectric loss tangent. 3 mol% or more is more preferable, 5 mol% or more is more preferable, 80 mol% or less is preferable, 50 mol% or less is more preferable, and 30 mol% or less is still more preferable.

The copolymer of the present disclosure includes "other monomer units" other than the above-mentioned aromatic vinyl monomer units, cross-linking group-containing monomer units, monomer units that give a homopolymer having a glass transition temperature of 150 ° C. or higher, and fluorine-containing monomer units ( polymerized units based on other monomers).

Examples of the above-mentioned other monomers include, for example, the above-mentioned aromatic vinyl monomers, cross-linking group-containing monomers, and fluorine-free monomers reactive with monomers that give homopolymers having a glass transition temperature of 150° C. or higher (hereinafter “fluorine-free monomers”). (also referred to as "monomer"). Examples of the fluorine-free monomer include hydrocarbon-based monomers.

The other monomer units (polymerized units based on other monomers) are excellent in low dielectric constant and low dielectric loss tangent, so that they are 0.1 mol% or more with respect to all polymerized units constituting the copolymer. is preferably 0.5 mol % or more, more preferably 1 mol % or more, preferably 50 mol % or less, more preferably 40 mol % or less, and even more preferably 30 mol % or less.

Examples of the above-mentioned other monomers include
Alkenes such as ethylene, propylene, butylene, isobutylene, 1-decene;
Alkyl vinyl ethers such as ethyl vinyl ether, propyl vinyl ether, butyl vinyl ether, isobutyl vinyl ether, cyclohexyl vinyl ether, 2-ethylhexyl vinyl ether;
Vinyl acetate, vinyl propionate, vinyl n-butyrate, vinyl isobutyrate, vinyl valerate, vinyl pivalate, vinyl caproate, vinyl caprylate, vinyl caprate, vinyl versatate, vinyl laurate, vinyl myristate, palmitic acid Vinyl, vinyl stearate, vinyl benzoate, vinyl para-t-butylbenzoate, vinyl cyclohexanecarboxylate, vinyl monochloroacetate, vinyl adipate, vinyl acrylate, vinyl methacrylate, vinyl crotonate, vinyl sorbate, cinnamic acid Vinyl esters such as vinyl, vinyl undecylenate, vinyl hydroxyacetate, vinyl hydroxypropionate, vinyl hydroxybutyrate, vinyl hydroxyvalerate, vinyl hydroxyisobutyrate, and vinyl hydroxycyclohexanecarboxylate;
Alkyl allyl ethers such as ethyl allyl ether, propyl allyl ether, butyl allyl ether, isobutyl allyl ether, cyclohexyl allyl ether;
Alkyl allyl esters such as ethyl allyl ester, propyl allyl ester, butyl allyl ester, isobutyl allyl ester, cyclohexyl allyl ester and the like are also included.
Among them, alkenes and alkyl vinyl ethers are preferable, 1-decene, ethyl vinyl ether, propyl vinyl ether, butyl vinyl ether, isobutyl vinyl ether, cyclohexyl vinyl ether and 2-ethylhexyl vinyl ether are more preferable, and 1-decene, cyclohexyl vinyl ether and 2-ethylhexyl vinyl ether are preferable. More preferred.

As the other monomer, a monomer having an alicyclic structure is preferably selected because it can impart solvent solubility to the copolymer.
As the monomer having an alicyclic structure, one or more selected from the group consisting of isobornyl methacrylate, isobornyl acrylate, cyclohexyl methacrylate, cyclohexyl acrylate, dicyclopentanyl acrylate and dicyclopentanyl methacrylate ( Meth)acrylates are preferred.

Functional group-containing hydrocarbon-based monomers can also be used as the hydrocarbon-based monomers as the other monomers. Examples of the functional group-containing hydrocarbon-based monomers include OH group-containing monomers. Examples of the functional group-containing hydrocarbon-based monomer include fluorine-free monomers having an OH group (hydroxyl group) such as hydroxyalkyl vinyl ethers such as hydroxyethyl vinyl ether, hydroxypropyl vinyl ether, hydroxybutyl vinyl ether, hydroxyisobutyl vinyl ether, and hydroxycyclohexyl vinyl ether. monomer;
fluorine-free monomers having a carboxyl group such as itaconic acid, succinic acid, succinic anhydride, fumaric acid, fumaric anhydride, crotonic acid, maleic acid, maleic anhydride, bis-2-ethylhexyl fumarate;
fluorine-free monomers having a glycidyl group such as glycidyl vinyl ether and glycidyl allyl ether;
non-fluorine-containing monomers having amino groups such as aminoalkyl vinyl ethers and aminoalkyl allyl ethers;
Non-fluorine-containing monomers having an amide group such as (meth)acrylamide and methylolacrylamide are included.

The copolymer of the present disclosure is preferably a thermosetting resin in terms of excellent low dielectric constant and low dielectric loss tangent. For example, a thermosetting resin can be provided by using the aromatic vinyl monomer, the cross-linking group-containing monomer, and the monomer that gives a homopolymer having a glass transition temperature of 150° C. or higher.

The fluorine content of the copolymer of the present disclosure is preferably 10% by mass or less, more preferably 5% by mass or less, and even more preferably 3% by mass or less, relative to the total mass of the copolymer, and contains fluorine. It may be nothing.
The fluorine content of the copolymer can be determined by elemental analysis using an automatic sample combustion apparatus.

The copolymer of the present disclosure preferably has a number average molecular weight of 1,000 to 50,000. Within such a range, solvent solubility and thermosetting are improved. The number average molecular weight of the fluorine-containing thermosetting resin is more preferably 2,000 to 30,000, still more preferably 4,000 to 20,000.
The number average molecular weight of the copolymer can be measured by gel permeation chromatography (GPC).

The glass transition temperature of the copolymer of the present disclosure is preferably 140 ° C. or higher, more preferably 150 ° C. or higher, further preferably 180 ° C. or higher, and 200 ° C., in terms of excellent electrical properties, particularly in terms of low dielectric loss tangent. Above is even more preferable, and 220° C. or higher is particularly preferable. The higher the glass transition temperature, the better, but from the viewpoint of workability, it is preferably 300° C. or less.
The above glass transition temperature is a value determined by the midpoint method from heat absorption in the second run using a DSC measuring device under the following conditions according to ASTM E1356-98.
Measurement conditions Heating rate; 20°C/min
Sample amount; 10 mg
Heat cycle; -50°C to 300°C, temperature rise, cooling, temperature rise

The thermosetting temperature of the copolymer of the present disclosure is preferably 300° C. or less, more preferably 270° C. or less, further preferably 250° C. or less, and particularly preferably 240° C. or less, in terms of excellent low dielectric constant and low dielectric loss tangent. , 230° C. or less is most preferred. Although the lower limit is not particularly limited, it is preferably 80° C. or higher, more preferably 100° C. or higher.
The thermosetting temperature is a value determined by the method described in Examples below.

The copolymer of the present disclosure preferably has solubility in methyl ethyl ketone (MEK) and toluene.
The solubility in MEK is evaluated by the method described in Examples below.

The copolymer of the present disclosure preferably has a dielectric constant (relative dielectric constant) of 2.50 or less, more preferably 2.47 or less, and even more preferably 2.30 or less, in terms of excellent low dielectric constant and low dielectric loss tangent. , 2.25 or less are particularly preferred. The lower limit is not particularly limited, and a smaller value is more desirable.
The dielectric constant (relative dielectric constant) is a value determined by the method described in Examples below.

The copolymer of the present disclosure preferably has a dielectric loss tangent of 0.0030 or less, more preferably 0.0028 or less, even more preferably 0.0025 or less, and 0.0020 or less in terms of excellent low dielectric constant and low dielectric loss tangent. is particularly preferred. The lower limit is not particularly limited, and a smaller value is more desirable.
The dielectric loss tangent is a value determined by the method described in Examples below.

The copolymer of the present disclosure can be obtained, for example, by appropriately adjusting the composition of the copolymer as described above, and in the presence of a chain transfer agent, the aromatic vinyl monomer, the crosslinking group-containing monomer, and the glass transition temperature It can be produced by a method for producing a copolymer including a step of polymerizing a monomer such as a monomer that gives a homopolymer having a temperature of 150° C. or higher.

The copolymer of the present disclosure can be produced by a solution polymerization method, an emulsion polymerization method, a suspension polymerization method, or a bulk polymerization method in polymerization. Among them, those obtained by the solution polymerization method are preferable.

In the copolymer of the present disclosure, in polymerization, monomers such as the aromatic vinyl monomer, the crosslinking group-containing monomer, and the monomer that gives a homopolymer having a glass transition temperature of 150° C. or higher are combined with an organic solvent, a polymerization initiator, and a chain. It is preferably produced by polymerizing by a solution polymerization method using a transfer agent or the like. The polymerization temperature is usually 0 to 150°C, preferably 5 to 130°C. The polymerization pressure is usually 0.1-10 MPaG (1-100 kgf/cm ² G).

Examples of the organic solvent include esters such as methyl acetate, ethyl acetate, propyl acetate, n-butyl acetate, and tert-butyl acetate; ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone, and cyclohexanone; hexane, cyclohexane, octane, and nonane. , decane, undecane, dodecane, mineral spirits; aromatic hydrocarbons such as benzene, toluene, xylene, naphthalene, solvent naphtha; methanol, ethanol, tert-butanol, iso-propanol, ethylene glycol mono alcohols such as alkyl ethers; cyclic ethers such as tetrahydrofuran, tetrahydropyran and dioxane; dimethylsulfoxide and the like, or mixtures thereof.

Examples of the polymerization initiator include persulfates such as ammonium persulfate and potassium persulfate (reducing agents such as sodium hydrogensulfite, sodium pyrosulfite, cobalt naphthenate, and dimethylaniline can also be used in combination, if necessary); oxidizing agent; (e.g., ammonium peroxide, potassium peroxide, etc.), a reducing agent (e.g., sodium sulfite, etc.) and a transition metal salt (e.g., iron sulfate, etc.); acetyl peroxide, benzoyl peroxide, diisobutyryl peroxide, Diacyl peroxides such as dilauroyl peroxide, didecanoyl peroxide, dicyclohexylperoxydicarbonate, bis(4-tert-butylcyclohexyl)peroxydicarbonate; isopropoxycarbonyl peroxide, tert-butoxycarbonyl peroxide, etc. dialkoxycarbonyl peroxides; ketone peroxides such as methyl ethyl ketone peroxide and cyclohexanone peroxide; hydroperoxides such as hydrogen peroxide, tert-butyl hydroperoxide and cumene hydroperoxide; oxide, dialkyl peroxides such as dicumyl peroxide; tert-butyl peroxyacetate, tert-butyl peroxypivalate, tert-butyl peroxy-2-ethylhexanoate, tert-butyl peroxy isopropyl monocarbonate, tert-butyl peroxybenzoate, tert-butyl peroxyneodecanoate, tert-butyl peroxylaurate, tert-hexyl peroxypivalate, tert-hexyl peroxy-2-ethylhexanoate, tert-hexyl per Alkyl peroxy esters such as oxyisopropyl monocarbonate; methylvaleronitrile), 2,2′-azobis(2-cyclopropylpropionitrile), 2,2′-azobisdimethylisobutyrate, 2,2′-azobis[2-(hydroxymethyl)propionitrile], 4, Azo compounds such as 4′-azobis(4-cyanopentenoic acid) can be used.

As the chain transfer agent, in addition to such compounds such as 2,4-diphenyl-4-methyl-pentene, for example, thiol compounds can be used. The thiol compound may be any thiol compound known to act as a chain transfer agent, preferably t-dodecylmercaptan, n-dodecylmercaptan, t-octylmercaptan, n-octylmercaptan, trimethylolpropane. tris-3-mercaptopropionate, pentaerythritol tetrakis-3-mercaptopropionate, dipentaerythritol hexa-3-mercaptopropionate and (tris-[(3-mercaptopropionyloxy)-ethyl]-isocyanurate ), etc. Among these, t-dodecylmercaptan, n-dodecylmercaptan, t-octylmercaptan, n-octylmercaptan and the like are particularly preferably used from the viewpoint of ease of polymerization control and toughness of the resulting copolymer. is a monoalkyl mercaptan having 5 to 30 carbon atoms.
Also, for example, alcohols can be used, preferably alcohols having 1 to 10 carbon atoms, more preferably monohydric alcohols having 1 to 10 carbon atoms. Specifically, methanol, ethanol, propanol, isopropanol, n-butanol, t-butanol, 2-methylpropanol, cyclohexanol, methylcyclohexanol, cyclopentanol, methylcyclopentanol, and dimethylcyclopentanol can be used. Among them, methanol, isopropanol, t-butanol, cyclohexanol, methylcyclohexanol, cyclopentanol, methylcyclopentanol and the like are preferable, and methanol and isopropanol are particularly preferable.

Among them, 2,4-diphenyl-4-methyl-pentene is preferred. For example, by combining 2,4-diphenyl-4-methyl-pentene with a diene monomer containing an olefin having a different reactivity, such as the diene monomer having a dicyclopentenyl group, gelling during polymerization can be prevented, and crosslinkability can be achieved in one step. groups can be introduced.

The copolymer composition (resin composition) of the present disclosure contains the above copolymer and a solvent.
The copolymer composition of the present disclosure is excellent in solvent solubility and thermosetting due to the copolymer having the above configuration. Also, by using it in a resin layer, the resin layer can be made to have a low dielectric constant and a low dielectric loss tangent.

In the copolymer composition of the present disclosure, the copolymer is the same as the copolymer of the present disclosure. Therefore, all suitable embodiments of the copolymers described in the copolymers of the present disclosure can be employed.

The copolymer composition of the present disclosure contains a solvent. The above solvent is preferably an organic solvent, and the organic solvent is not particularly limited. Esters such as ethyl acetate, butyl acetate, isopropyl acetate, isobutyl acetate, cellosolve acetate, and propylene glycol methyl ether acetate; Ketones such as ketones and cyclohexanone; Cyclic ethers such as tetrahydrofuran and dioxane; Amides such as N,N-dimethylformamide and N,N-dimethylacetamide; Aromatic hydrocarbons such as toluene and xylene; Propylene glycol methyl ether alcohols such as hexane; hydrocarbons such as hexane and heptane; and mixed solvents thereof.

The copolymer composition of the present disclosure may further include monomer components such as the aforementioned monomers and other monomer components such as styrene and methyl (meth)acrylate.

The copolymer composition of the present disclosure may contain a cross-linking agent from the viewpoint of improving thermosetting properties. The cross-linking agent used in the present embodiment is not particularly limited as long as it is a cross-linking agent having two or more carbon-carbon unsaturated double bonds in its molecule. That is, the cross-linking agent forms cross-links by reacting with a copolymer of the aromatic vinyl monomer of the present disclosure, a cross-linking group-containing monomer, and a monomer that gives a homopolymer having a glass transition temperature of 150 ° C. or higher, and is cured. Anything that can make it possible. The cross-linking agent is preferably a compound having two or more carbon-carbon unsaturated double bonds at its terminals. The cross-linking agents may be used alone or in combination of two or more.
Specific cross-linking agents include trialkenyl isocyanurate compounds such as triallyl isocyanurate (TAIC), bismaleimides described later, divinylbenzene, dicyclopentenyl (meth)acrylate, and pentaerythritol tri(meth)acrylate. Compounds such as monomer components containing vinyl groups and vinyl compounds having two or more vinyl groups in the molecule such as polybutadiene can be used. As the vinyl compound having two or more vinyl groups in the molecule, a polymer containing a plurality of vinyl groups such as polybutadiene is preferable. The copolymer composition of the present disclosure preferably contains the above polymer containing a plurality of vinyl groups or the above monomer component containing a plurality of vinyl groups. From the viewpoint of improving thermosetting properties, bismaleimides are preferred. Preferred bismaleimides include, for example, 1,2-bis(maleimido)ethane, N-succinimidyl-3-maleimidopropionate, 4,4'-diphenylmethanebismaleimide, N,N'-m-phenylenebismaleimide, N,N'-p-phenylenebismaleimide, bisphenol A diphenyl ether bismaleimide, 3,3'-dimethyl-5,5'-diethyl-4,4'-diphenylmethanebismaleimide, 4-methyl-1,3-phenylenebis Maleimide, 1,6′-bismaleimido-(2,2,4-trimethyl)hexane, 1-maleimido-3-maleimidomethyl-3,5,5-trimethylcyclohexane, 1,1′-(cyclohexane-1,3 -diylbis(methylene))bis(1H-pyrrole-2,5-dione), 1,1′-(4,4′-methylenebis(cyclohexane-4,1-diyl))bis(1H-pyrrole-2,5 -dione), 1,1′-(3,3′-(piperazine-1,4-diyl)bis(propane-3,1-diyl))bis(1H-pyrrole-2,5-dione), 2, 2'-(ethylenedioxy)bis(ethylmaleimide), succinimidyl-4-(N-maleimidomethyl)cyclo-hexane-1-carboxylate, 2,2-bis[4-(4-maleimidophenoxy)phenyl]propane etc.
For the polybutadiene used in this embodiment, 1,2-polybutadiene, for example, can be suitably used. Commercially available products may be used, for example, it is available as a product of JSR Corporation, and liquid polybutadiene: product names B-1000, 2000, and 3000 can be obtained from Nippon Soda Co., Ltd. Further, as a copolymer containing a 1,2-polybutadiene structure that can be suitably used, "Ricon 100" manufactured by TOTAL CRAY VALLEY can be exemplified. The maleimides used in the present embodiment may be commercially available, for example, "BMI-2300" manufactured by Daiwa Kasei Kogyo Co., Ltd., "MIR-3000" manufactured by Nippon Kayaku Co., Ltd. "BMI-70" manufactured by the company and "BMI-80" manufactured by K.I Kasei Co., Ltd. can be preferably used.
The content of the maleimides in the copolymer resin composition can be appropriately set according to the desired properties, and is not particularly limited. The content of the maleimide compound is preferably 1 part by mass or more, and preferably 5 parts by mass or more, when the solid content of the copolymer (resin solid content) in the copolymer composition is 100 parts by mass. more preferred. The upper limit is preferably 90 parts by mass or less, more preferably 60 parts by mass or less, even more preferably 40 parts by mass or less, and may be 30 parts by mass or less. Such a range tends to provide a good balance between electrical properties and curing reactivity.
Only one type of maleimides may be used, or two or more types may be used. When two or more kinds are used, the total amount is preferably within the above range.

Furthermore, the above-mentioned polymerization initiator and photopolymerization initiator may be included. Photoinitiators include, for example, benzoins such as benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin propyl ether, benzoin isobutyl ether; acetophenone, 2,2-diethoxy-2-phenylacetophenone, 2,2-diethoxy-2 -phenylacetophenone, 1,1-dichloroacetophenone, 2-hydroxy-2-methyl-phenylpropan-1-one, diethoxyacetophenone, 1-hydroxycyclohexylphenyl ketone, 2-methyl-1-[4-(methylthio)phenyl ]-Acetophenones such as 2-morpholinopropan-1-one; Anthraquinones such as 2-ethylanthraquinone, 2-tert-butylanthraquinone, 2-chloroanthraquinone and 2-amylanthraquinone; 2,4-diethylthioxanthone, 2- Thioxanthones such as isopropylthioxanthone and 2-chlorothioxanthone; Ketals such as acetophenone dimethyl ketal and benzyl dimethyl ketal; Benzophenone, 4-benzoyl-4'-methyldiphenyl sulfide, 4,4'-bismethylaminobenzophenone benzophenones; and phosphine oxides such as 2,4,6-trimethylbenzoyldiphenylphosphine oxide and bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide.
Each of these may be used alone, or two or more of them may be used in combination.

The copolymer composition of the present disclosure may be free of cross-linking agents (curing agents), or free of cross-linking agents (curing agents) and curing accelerators. For example, when the above copolymer contains a dicyclopentenyl group, it can be self-crosslinked without using a crosslinking agent or curing accelerator. Therefore, it is possible to improve electrical properties without adding extra components.

In the copolymer composition of the present disclosure, the copolymer preferably contains 10% by mass or more, more preferably 25% by mass or more, still more preferably 40% by mass or more, based on 100% by mass of solids. % by mass or less, or 80% by mass or less.

The copolymer composition of the present disclosure may also contain flame retardants, inorganic fillers, silane coupling agents, release agents, pigments, emulsifiers, and the like.

The copolymer composition of the present disclosure may contain various additives depending on the required properties. Additives include pigment dispersants, antifoaming agents, leveling agents, UV absorbers, light stabilizers, thickeners, adhesion improvers, matting agents and the like.

From the viewpoint of thermosetting properties, the copolymer composition of the present disclosure preferably has a gel fraction of 30% or more. The gel fraction is more preferably 35% or more, still more preferably 40% or more, and particularly preferably 50% or more.
In addition, the said gel fraction is a value measured by the method described in the below-mentioned Example.

The method of preparing the copolymer composition of the present disclosure is not particularly limited. For example, a method of mixing a solution or dispersion of a copolymer with other components can be used.

The copolymer composition of the present disclosure can be suitably used as a resin layer of a laminate including a base material and a resin layer provided on the base material, and can be particularly suitably used as a resin layer of a metal-clad laminate. . It can also be used for resins for powder coatings, resins for optical applications, and resist materials. The present disclosure also relates to films comprising the above copolymers. The present disclosure also relates to a laminate including a substrate and a resin layer provided on the substrate, wherein the resin layer contains the copolymer.

The copolymer composition of the present disclosure is a metal-clad laminate comprising a metal foil and a resin layer provided on the metal foil, wherein the resin layer is formed from the copolymer composition of the present disclosure. It can be suitably used for metal-clad laminates. A resin layer can be formed by curing the copolymer composition of the present disclosure. The present disclosure also relates to a metal-clad laminate comprising a metal foil and a resin layer provided on the metal foil, wherein the resin layer contains the copolymer.

The metal-clad laminate includes a metal foil and a resin layer. The resin layer has excellent insulating properties and plays a role as a base material of the metal-clad laminate.

Examples of metal foils include metal foils made of copper, aluminum, iron, nickel, chromium, molybdenum, tungsten, zinc, or alloys thereof, preferably copper foil. In addition, for the purpose of improving adhesion, chemical or mechanical surface treatment may be applied with siding, nickel plating, copper-zinc alloy plating, aluminum alcoholate, aluminum chelate, silane coupling agent, or the like.

As long as the metal-clad laminate comprises the metal foil and the resin layer, the metal-clad laminate may further include other layers, and each of the metal foil and the resin layer may be one kind, or two or more kinds. may be

The metal-clad laminate may further include a second resin layer provided on the resin layer (hereinafter referred to as "first resin layer"). That is, the metal-clad laminate may be formed by laminating a metal foil, a first resin layer, and a second resin layer in this order. The first resin layer not only serves as a base material, but may also serve as an adhesive layer that bonds the metal foil and the second resin layer.
In addition, in the metal-clad laminate, the first resin layer may be provided on the surface of the metal foil different from the surface on which the first resin layer is provided (the opposite side). That is, the metal-clad laminate may be one in which the first resin layer, the metal foil, and the first resin layer are laminated in this order, or the first resin layer, the metal foil, and the first resin layer. , and the second resin layer.

Resins used in conventional printed circuit boards can be used for the second resin layer, but the second resin layer is at least one selected from the group consisting of polyethylene terephthalate and polyimide. It is preferably made of resin, and more preferably made of polyimide from the viewpoint of heat resistance.

A film having a thickness of 1 to 150 μm can be used as the first resin layer. When the metal foil and the second adhesive layer are bonded via the first resin layer, the thickness of the first resin layer after drying can be 1 to 100 μm.

A resin film having a thickness of 1 to 150 μm can be used as the second resin layer.

The metal-clad laminate can be obtained by a manufacturing method including a step of obtaining a metal-clad laminate by bonding a metal foil and a film made of the copolymer composition.
As the bonding method, a method of superimposing the metal foil and the film containing the copolymer composition and then thermocompression bonding them at 50 to 300° C. with a hot press is suitable.
The production method may further include the step of molding the copolymer composition to obtain a film made of the copolymer.
Examples of the molding method include, but are not limited to, methods such as melt extrusion molding, solvent casting, and spraying. The copolymer composition may contain an organic solvent, a curing agent, etc., and may contain a curing accelerator, a pigment dispersant, an antifoaming agent, a leveling agent, a UV absorber, a light stabilizer, and a thickener. , adhesion improvers, matting agents, and the like.

The metal-clad laminate can also be obtained by a manufacturing method including a step of applying the copolymer composition to a metal foil to form a first resin layer.
In the above manufacturing method, after the step of forming the first resin layer, a resin film to be the second resin layer is further adhered on the first resin layer, and the metal foil and the first and second It may include a step of obtaining a metal-clad laminate including a resin layer. Examples of the resin film include a film made of a resin suitable for forming the second resin layer.
As a method for adhering the resin film, a method of thermocompression bonding at 50 to 300° C. using a hot press is suitable.
In the above production method, methods for applying the composition for forming the first resin layer to the metal foil include brush coating, dip coating, spray coating, comma coating, knife coating, die coating, lip coating, and roll coating. , curtain coating, and the like. After applying the composition, it can be cured by drying in a hot air drying oven or the like at 25 to 200° C. for 1 minute to 1 week.

The metal-clad laminate includes a step of applying the copolymer composition to a resin film that will be the second resin layer to form a first resin layer, and a first resin layer obtained by the forming step. A manufacturing method including a step of bonding a metal foil to a first resin layer of a laminate comprising a second resin layer to obtain a metal-clad laminate comprising the metal foil and the first and second resin layers can also be manufactured by Examples of the resin film include a film made of a resin suitable for forming the second resin layer.
Methods for applying the composition for forming the first resin layer to the resin film include brush coating, dip coating, spray coating, comma coating, knife coating, die coating, lip coating, roll coater coating, curtain coating, and the like. method. After applying the composition, it can be cured by drying in a hot air drying oven or the like at 25 to 200° C. for 1 minute to 1 week.
In the above manufacturing method, the method of bonding the metal foil to the first resin layer of the laminate composed of the first resin layer and the second resin layer includes: A preferred method is to laminate the laminate and the metal foil so that the first resin layer and the metal foil of the laminate are adhered, and then thermocompress them with a hot press at 50 to 300 ° C. .

The metal-clad laminate can be applied to a printed circuit board provided with a pattern circuit formed by etching the metal foil of the metal-clad laminate. The present disclosure also relates to a printed circuit board comprising a pattern circuit formed by etching the metal foil of the metal-clad laminate. The printed board may be a flexible board or a rigid board, but is preferably a rigid board.
The printed circuit board may include a coverlay film on the metal-clad laminate, and the coverlay film may be adhered to the metal-clad laminate via the resin layer.
The etching method is not limited, and conventionally known methods can be employed. Moreover, the pattern circuit is not limited, and a printed circuit board having any pattern circuit may be used.

Applications of the printed circuit board are not limited. For example, since the printed circuit board has a resin layer with a low dielectric constant and a low dielectric loss tangent, it is used in applications with high frequency bands such as 4G (37.5 Mbps) and 5G (several G to 20 Gbps). It can also be used for substrates.

The present disclosure will now be described with reference to examples, but the present disclosure is not limited only to such examples.
EXAMPLES Hereinafter, the present disclosure will be described more specifically with reference to examples.

The physical properties described in this specification are measured by the following measuring methods.

(1) NMR analysis:
Measurement device: NMR measurement device: 1H-NMR measurement conditions manufactured by VARIAN: 400 MHz (tetramethylsilane = 0 ppm)

(2) Elemental analysis (measurement of fluorine content (mass%))
Measuring device: automatic sample combustion device (Mitsubishi Chemical Co., Ltd. AQF-100) ion chromatography (DIONEX ICS-1500 Ion Chromatography System) built-in sample 3 mg

(3) Molecular weight measuring device: Shodex GPC-104 manufactured by Showa Denko Co., Ltd.
Measurement conditions: Tetrahydrofuran is used as an eluent, and polystyrene with a known molecular weight is used as a molecular weight standard sample.

(4) Glass transition temperature According to ASTM E1356-98, the glass transition temperature and crystalline melting point were determined by the midpoint method from the heat absorption in the second run using a DSC measurement device manufactured by METLER TOLEDO.
Measurement conditions Heating rate; 20°C/min
Sample amount; 10 mg
Heat cycle; -50°C to 300°C, temperature rise, cooling, temperature rise

ただし、式中の記号はつぎのものである。
Ｄ：空洞共振器直径（ｍｍ）
Ｍ：空洞共振器片側長さ（ｍｍ）
Ｌ：サンプル長さ（ｍｍ）
ｃ：光速（ｍ／ｓ）
Ｉｄ：減衰量（ｄＢ）
Ｆ０：共振周波数（Ｈｚ）
Ｆ１：共振点からの減衰量が３ｄＢである上側周波数（Ｈｚ）
Ｆ２：共振点からの減衰量が３ｄＢである下側周波数（Ｈｚ）
ε０：真空の誘電率（Ｈ／ｍ）
εｒ：サンプルの比誘電率
μ０：真空の透磁率（Ｈ／ｍ）
Ｒｓ：導体空洞の表面粗さも考慮した実効表面抵抗（Ω）
Ｊ０：－０．４０２７５９
Ｊ１：３．８３１７１ (5) Dielectric constant and dielectric loss tangent A film of the copolymer prepared in Synthesis Example was vacuum heat-pressed. The relative permittivity and dielectric loss tangent of the produced film (Sample F) were measured as follows.
Using a network analyzer and a cavity resonator, changes in the resonant frequency and Q value of the sample F produced above were measured, and the dielectric loss tangent (tan δ) at 12 GHz was calculated according to the following equation. The cavity resonator method is according to Professor Kobayashi of Saitama University [Non-destructive measurement of complex permittivity of dielectric plate material by cavity resonator method MW87-53].
tan δ=(1/Qu)×{1+(W2/W1)}−(Pc/ωW1)

However, the symbols in the formula are as follows.
D: Cavity resonator diameter (mm)
M: Cavity resonator one-side length (mm)
L: sample length (mm)
c: speed of light (m/s)
Id: attenuation (dB)
F0: resonance frequency (Hz)
F1: upper frequency (Hz) at which the attenuation from the resonance point is 3 dB
F2: lower frequency (Hz) at which the attenuation from the resonance point is 3 dB
ε0: permittivity of vacuum (H/m)
εr: Relative permittivity of sample μ0: Permeability of vacuum (H/m)
Rs: Effective surface resistance (Ω) considering the surface roughness of the conductor cavity
J0: -0.402759
J1: 3.83171

(6) Solvent Solubility Evaluation 20 g of the copolymer prepared in Synthesis Example was weighed in 30 g of methyl ethyl ketone in a 100 ml sample bottle and shaken to visually confirm the solubility.

(7) Thermosetting evaluation (gel fraction)
2 g of the solution prepared in the solvent solubility evaluation or the cured composition using the copolymer and the cross-linking agent was placed in an aluminum cup and dried by heating at each set baking temperature for 1 hour to obtain a thermoset. The cured material was taken and wrapped in a pre-weighed 400 mesh metal wire mesh. 25 ml of methyl ethyl ketone and the cured product wrapped in wire netting were placed in a 50 ml sample tube, and the cured product was immersed in methyl ethyl ketone for 24 hours. After that, the wire mesh was taken out, dried, and the mass after drying was measured, and the mass of the dried and cured product after immersion in methyl ethyl ketone was calculated.
The gel fraction was calculated as (mass of dried cured product after immersion in methyl ethyl ketone/mass of cured product before immersion in methyl ethyl ketone×100).

(8) Thermosetting temperature The thermosetting temperature is the peak top temperature of the exothermic peak observed during measurement with a DSC measurement device, or a differential thermal/thermogravimetry device [TG-DTA] (trade name: TG/DTA7200 , Hitachi High-Tech Science Co., Ltd.), 10 mg of the sample was heated from room temperature at a heating rate of 10 ° C./min, and the temperature of the peak top of the exothermic peak seen in the temperature range where the weight loss was less than 1% was heat cured. temperature.

(9) Coefficient of linear expansion A film (sample piece) of the copolymer prepared in Synthesis Example was prepared, and the coefficient of linear expansion (coefficient of linear expansion) was measured as follows.
The coefficient of linear expansion of the film was obtained by TMA measurement in the following compression mode using TMA-7100 (manufactured by Hitachi High-Tech Science Co., Ltd.).
[Tension mode measurement]
As a sample piece, an extruded film with a thickness of 760 μm cut into a length of 10 mm and a width of 10 mm was used, and while compressing with a load of 49 mN, the temperature was increased at a rate of 2 ° C./min at 30 to 200 ° C. Linear expansion from the displacement of the sample. asked for a rate.

<Synthesis of copolymer>
Synthesis example 1
100 g of methyl isobutyl ketone, 16 g of styrene, 24 g of dicyclopentenyl vinyl ether, 24 g of cyclohexylmaleimide (a homopolymer having a glass transition temperature of 300° C.), and 0.8 g of 2,4-diphenyl-4-methyl-1-pentene were placed in a 300-ml four-necked flask. was put in. The internal temperature was adjusted to 70° C., 2 g of t-butyl peroxypivalate was added, and the mixture was reacted for 3 hours. After cooling the reaction vessel, the reaction mixture was poured into a large amount of methanol at room temperature to precipitate a copolymer. The resulting copolymer was washed with methanol, filtered and dried to obtain a copolymer.
According to NMR analysis, the resulting copolymer had a composition of 41 mol % of styrene-derived structures, 15 mol % of dicyclopentenyl vinyl ether-derived structures, and 44 mol % of cyclohexylmaleimide-derived structures.
Molecular weight analysis revealed a number average molecular weight (Mn) of 16,000 and a weight average molecular weight (Mw) of 41,000. The glass transition temperature (Tg) was 180°C.
As a result of DSC measurement up to 250°C, an exothermic peak was observed from around 190°C to 250°C.

Synthesis example 2
A 300 ml four-necked flask was charged with 60 g of methyl isobutyl ketone, 11 g of styrene, 14 g of dicyclopentadiene, and 5 g of cyclohexylmaleimide. The inner temperature was set to 90° C., 2 g of t-butylperoxy-2-ethylhexanoate was added, and the mixture was reacted for 3 hours. After cooling the reaction vessel, the reaction mixture was poured into a large amount of methanol at room temperature to precipitate a copolymer. The resulting copolymer was washed with methanol, filtered and dried to obtain a copolymer.
Elemental analysis and NMR analysis revealed that the resulting copolymer had a composition of 60 mol % of styrene-derived structures, 6 mol % of dicyclopentadiene-derived structures, and 34 mol % of cyclohexylmaleimide-derived structures.
Molecular weight analysis revealed a number average molecular weight (Mn) of 14,000 and a weight average molecular weight (Mw) of 31,000. The glass transition temperature (Tg) was 145°C.
(As a result of DSC measurement up to 200°C, no exothermic peak was observed.)

Synthesis example 3
95 g of methyl isobutyl ketone, 12 g of styrene, 15 g of dicyclopentadiene, 20 g of cyclohexylmaleimide, 18 g of 1,2,2-trifluoroethenylbenzene, and 4 g of 2,4-diphenyl-4-methyl-1-pentene were placed in a 300 ml four-necked flask. put in. The internal temperature was adjusted to 70° C., 2 g of t-butyl peroxypivalate was added, and the mixture was reacted for 3 hours. After cooling the reaction vessel, the reaction mixture was poured into a large amount of methanol at room temperature to precipitate a copolymer. The resulting copolymer was washed with methanol, filtered and dried to obtain a copolymer.
Elemental analysis and NMR analysis revealed that the resulting copolymer had 6 mol% of the structure derived from 1,2,2-trifluoroethenylbenzene (trifluorostyrene), 59 mol% of the structure derived from styrene, and dicyclopententa. The composition was 5 mol % of diene-derived structures and 30 mol % of cyclohexylmaleimide-derived structures.
Molecular weight analysis revealed a number average molecular weight (Mn) of 14,000 and a weight average molecular weight (Mw) of 34,000. The glass transition temperature (Tg) was 161°C. Elemental analysis showed a fluorine content of 3.4% by mass.
As a result of DSC measurement up to 200°C, an exothermic peak was observed from around 170°C to around 200°C.

Synthesis example 4
100 g of methyl isobutyl ketone, 35 g of dicyclopentenyl vinyl ether, 18 g of cyclohexylmaleimide, and 2 g of 2,4-diphenyl-4-methyl-1-pentene were introduced into a 300 ml four-necked flask. The internal temperature was adjusted to 70° C., 1 g of t-butylperoxy-2-ethylhexanoate was added, and the mixture was reacted for 3 hours. After cooling the reaction vessel, the reaction mixture was poured into a large amount of methanol at room temperature to precipitate a copolymer. The resulting copolymer was washed with methanol, filtered and dried to obtain a copolymer.
Elemental analysis and NMR analysis revealed that the obtained copolymer had a composition of 46 mol % of the structure derived from dicyclopentenylvinyl ether and 54 mol % of the structure derived from cyclohexylmaleimide.
Molecular weight analysis revealed a number average molecular weight (Mn) of 4,500 and a weight average molecular weight (Mw) of 7,800. The glass transition temperature (Tg) was 205°C.
As a result of the same DSC measurement, an exothermic peak was observed from 160°C to around 240°C.

Synthesis example 5
100 g of methyl isobutyl ketone, 29 g of dicyclopentadiene, 18 g of cyclohexylmaleimide, and 2 g of 2,4-diphenyl-4-methyl-1-pentene were introduced into a 300 ml four-necked flask. The internal temperature was adjusted to 70° C., 1 g of t-butyl peroxypivalate was added, and the mixture was reacted for 3 hours. After cooling the reaction vessel, the reaction mixture was poured into a large amount of methanol at room temperature to precipitate a copolymer. The resulting copolymer was washed with methanol, filtered and dried to obtain a copolymer.
Elemental analysis and NMR analysis revealed that the obtained copolymer had a composition of 36 mol % of the structure derived from dicyclopentadiene and 64 mol % of the structure derived from cyclohexylmaleimide.
Molecular weight analysis revealed a number average molecular weight (Mn) of 2,000 and a weight average molecular weight (Mw) of 3,000. The glass transition temperature (Tg) was 225°C.
As a result of DSC measurement up to 220°C, an exothermic peak was observed in the vicinity of 180°C to 220°C.

Polymer compositions and physical properties of the polymers prepared in Synthesis Examples 1 to 5 and copolymer films prepared using the polymers were measured and evaluated, and the results are shown in Table 1.
Further, the gel fractions of the polymers prepared in Synthesis Examples 1 to 5 were measured for the cured products prepared at the baking temperatures shown in Table 1. The results are shown in Table 1.

<Preparation of copolymer composition>
According to the formulation shown in Table 2, a MEK (methyl isobutyl ketone) solution (solid content concentration 40% by mass (polymer solution)) of the polymer prepared in Synthesis Examples 1 to 3 was added to a cross-linking agent A solution (4,4'-diphenylmethanebismaleimide). acetone solution (concentration 3% by mass)) or crosslinking agent B solution (N,N'-(2,2,4-trimethylhexane-1,6-diyl)bismaleimide methyl ethyl ketone solution (concentration 10% by mass)) Each cured composition was prepared by blending. The prepared composition was baked at the baking temperature shown in Table 2 to obtain a cured product, and the gel fraction was measured. The results are listed in Table 2.

From Table 2, it was confirmed that the curing temperature can be lowered by adding a cross-linking agent.

<Synthesis of copolymer>
Synthesis example 6
120 parts by mass of methyl isobutyl ketone, 14 parts by mass of styrene, 40 parts by mass of cyclohexylmaleimide, 15 parts by mass of dicyclopentenyl vinyl ether, and 6 parts by mass of bis-2-ethylhexyl fumarate were charged into a 300 ml four-necked flask. The internal temperature was set to 85° C., 0.4 parts by mass of t-butylperoxy-2-ethylhexanoate was added, and the reaction was allowed to proceed for 3 hours. After cooling the reaction vessel, the reaction mixture was poured into a large amount of methanol at room temperature to precipitate a copolymer. The resulting copolymer was washed with methanol, filtered and dried to obtain a copolymer.
According to NMR analysis, the obtained copolymer had a structure derived from styrene of 30 mol%, a structure derived from dicyclopentenyl vinyl ether at 11 mol%, a structure derived from cyclohexylmaleimide at 56 mol%, and a structure derived from bis-2-ethylhexyl fumarate. structure was 3 mol %.
Molecular weight analysis revealed a number average molecular weight (Mn) of 25,728 and a weight average molecular weight (Mw) of 187,116. The glass transition temperature (Tg) was 205°C.
As a result of TG-DTA measurement up to 600°C, an exothermic peak was observed from around 190°C to 250°C.

Synthesis example 7
120 parts by mass of methyl isobutyl ketone, 23 parts by mass of styrene, 40 parts by mass of cyclohexylmaleimide, 13 parts by mass of dicyclopentadiene, and 6 parts by mass of bis-2-ethylhexyl fumarate were charged into a 300 ml four-necked flask. The internal temperature was set to 85° C., 0.4 parts by mass of t-butylperoxy-2-ethylhexanoate was added, and the reaction was allowed to proceed for 3 hours. After cooling the reaction vessel, the reaction mixture was poured into a large amount of methanol at room temperature to precipitate a copolymer. The resulting copolymer was washed with methanol, filtered and dried to obtain a copolymer.
According to NMR analysis, the obtained copolymer had a structure derived from styrene of 40 mol%, a structure derived from dicyclopentadiene of 5 mol%, a structure derived from cyclohexylmaleimide of 52 mol%, and a structure derived from bis-2-ethylhexyl fumarate. The composition had a structure of 3 mol %.
Molecular weight analysis revealed a number average molecular weight (Mn) of 29,862 and a weight average molecular weight (Mw) of 89,407. The glass transition temperature (Tg) was 190°C.
As a result of TG-DTA measurement up to 600°C, an exothermic peak was observed from around 190°C to 250°C.

Synthesis example 8
120 parts by mass of methyl isobutyl ketone, 15.6 parts by mass of styrene, 40 parts by mass of cyclohexylmaleimide, 15 parts by mass of dicyclopentenyl vinyl ether, 6 parts by mass of bis-2-ethylhexyl fumarate, and 9 parts by mass of trifluorostyrene in a 300 ml four-necked flask. was put in. The internal temperature was adjusted to 85° C., 0.2 parts by mass of t-butylperoxy-2-ethylhexanoate was added, and the mixture was reacted for 3 hours. After cooling the reaction vessel, the reaction mixture was poured into a large amount of methanol at room temperature to precipitate a copolymer. The resulting copolymer was washed with methanol, filtered and dried to obtain a copolymer.
According to NMR analysis, the resulting copolymer contained 3 mol% of a structure derived from trifluorostyrene, 33 mol% of a structure derived from styrene, 9 mol% of a structure derived from dicyclopentenyl vinyl ether, and a structure derived from cyclohexylmaleimide. The composition was 52 mol % and the structure derived from bis-2-ethylhexyl fumarate was 3 mol %.
Molecular weight analysis revealed a number average molecular weight (Mn) of 38,829 and a weight average molecular weight (Mw) of 249,053. The glass transition temperature (Tg) was 195°C.
As a result of TG-DTA measurement up to 600°C, an exothermic peak was observed from around 190°C to 250°C.

Synthesis example 9
110 parts by mass of methyl isobutyl ketone, 7.8 parts by mass of styrene, 40 parts by mass of cyclohexylmaleimide, 11.7 parts by mass of dicyclopentadiene, and 10 parts by mass of 1-decene were charged into a 300 ml four-necked flask. The internal temperature was adjusted to 85° C., 0.2 parts by mass of t-butylperoxy-2-ethylhexanoate was added, and the mixture was reacted for 3 hours. After cooling the reaction vessel, the reaction mixture was poured into a large amount of methanol at room temperature to precipitate a copolymer. The resulting copolymer was washed with methanol, filtered and dried to obtain a copolymer.
According to NMR analysis, the resulting copolymer contained 16 mol% of structures derived from styrene, 8 mol% of structures derived from dicyclopentadiene, 66 mol% of structures derived from cyclohexylmaleimide, and 10 mol% of structures derived from 1-decene. The composition was mol %.
Molecular weight analysis revealed a number average molecular weight (Mn) of 26,910 and a weight average molecular weight (Mw) of 86,654. The glass transition temperature (Tg) was 227°C.
As a result of TG-DTA measurement up to 600°C, an exothermic peak was observed from around 190°C to 250°C.

Synthesis example 10
120 parts by mass of methyl isobutyl ketone, 18 parts by mass of styrene, 40 parts by mass of cyclohexylmaleimide, 12 parts by mass of dicyclopentadiene, and 6 parts by mass of limonene were put into a 300 ml four-necked flask. The internal temperature was adjusted to 85° C., 0.2 parts by mass of t-butylperoxy-2-ethylhexanoate was added, and the mixture was reacted for 3 hours. After cooling the reaction vessel, the reaction mixture was poured into a large amount of methanol at room temperature to precipitate a copolymer. The resulting copolymer was washed with methanol, filtered and dried to obtain a copolymer.
According to NMR analysis, the resulting copolymer contained 32 mol% of the structure derived from styrene, 5 mol% of the structure derived from dicyclopentadiene, 58 mol% of the structure derived from cyclohexylmaleimide, and 5 mol% of the structure derived from limonene. was the composition of
Molecular weight analysis revealed a number average molecular weight (Mn) of 22,677 and a weight average molecular weight (Mw) of 85,014. The glass transition temperature (Tg) was 220°C.
As a result of TG-DTA measurement up to 600°C, an exothermic peak was observed from around 190°C to 250°C.

Synthesis Example 11
120 parts by mass of methyl isobutyl ketone, 18 parts by mass of styrene, 40 parts by mass of cyclohexylmaleimide, 12 parts by mass of dicyclopentadiene, and 6 parts by mass of 2-ethylhexyl vinyl ether were charged into a 300 ml four-necked flask. The internal temperature was adjusted to 85° C., 0.2 parts by mass of t-butylperoxy-2-ethylhexanoate was added, and the mixture was reacted for 3 hours. After cooling the reaction vessel, the reaction mixture was poured into a large amount of methanol at room temperature to precipitate a copolymer. The resulting copolymer was washed with methanol, filtered and dried to obtain a copolymer.
According to NMR analysis, the resulting copolymer contained 34 mol% of a structure derived from styrene, 4 mol% of a structure derived from dicyclopentadiene, 56 mol% of a structure derived from cyclohexylmaleimide, and a structure derived from 2-ethylhexyl vinyl ether. The composition was 6 mol %.
Molecular weight analysis revealed a number average molecular weight (Mn) of 5,665 and a weight average molecular weight (Mw) of 10,242. The glass transition temperature (Tg) was 206°C.
As a result of TG-DTA measurement up to 600°C, an exothermic peak was observed from around 190°C to 250°C.

Synthesis Example 12
120 parts by mass of methyl isobutyl ketone, 19 parts by mass of styrene, 33 parts by mass of cyclohexylmaleimide, 9 parts by mass of dicyclopentadiene, and 10.3 parts by mass of N-dodecylmaleimide were charged into a 300 ml four-necked flask. The internal temperature was adjusted to 85° C., 0.2 parts by mass of t-butylperoxy-2-ethylhexanoate was added, and the mixture was reacted for 3 hours. After cooling the reaction vessel, the reaction mixture was poured into a large amount of methanol at room temperature to precipitate a copolymer. The resulting copolymer was washed with methanol, filtered and dried to obtain a copolymer.
According to NMR analysis, the resulting copolymer contained 43 mol% of a structure derived from styrene, 4 mol% of a structure derived from dicyclopentadiene, 43 mol% of a structure derived from cyclohexylmaleimide, and a structure derived from N-dodecylmaleimide. The composition was 10 mol %.
Molecular weight analysis revealed a number average molecular weight (Mn) of 35,618 and a weight average molecular weight (Mw) of 124,375. The glass transition temperature (Tg) was 162°C.
As a result of TG-DTA measurement up to 600°C, an exothermic peak was observed from around 170°C to 250°C.

Synthesis Example 13
100 parts by mass of methyl isobutyl ketone, 16.2 parts by mass of styrene, 25.3 parts by mass of N-benzylmaleimide, 12 parts by mass of dicyclopentadiene, and 2.5 parts by mass of 1-decene were charged into a 300 ml four-necked flask. The internal temperature was adjusted to 85° C., 0.2 parts by mass of t-butylperoxy-2-ethylhexanoate was added, and the mixture was reacted for 3 hours. After cooling the reaction vessel, the reaction mixture was poured into a large amount of methanol at room temperature to precipitate a copolymer. The resulting copolymer was washed with methanol, filtered and dried to obtain a copolymer.
According to NMR analysis, the resulting copolymer contained 41 mol% of a structure derived from styrene, 3 mol% of a structure derived from dicyclopentadiene, 52 mol% of a structure derived from N-benzylmaleimide, and a structure derived from 1-decene. was a composition of 4 mol %.
Molecular weight analysis revealed a number average molecular weight (Mn) of 24,540 and a weight average molecular weight (Mw) of 98,036. The glass transition temperature (Tg) was 162°C.
As a result of TG-DTA measurement up to 600°C, an exothermic peak was observed from around 170°C to 250°C.

The polymer compositions and physical properties of the polymers prepared in Synthesis Examples 6 to 13 and the copolymer films prepared using the polymers were measured and evaluated.
Further, the gel fractions of the polymers prepared in Synthesis Examples 6 to 13 were measured for the cured products prepared at the baking temperatures shown in Table 3. The results are listed in Table 3.

Example 18
10 parts by weight of the polymer obtained in Synthesis Example 9, 2 parts by weight of polybutadiene (B-2000 manufactured by Nippon Soda Co., Ltd.) and 0.1 parts by weight of initiator (Percumyl D-40 manufactured by NOF Corporation) were added to 48 parts by weight of methyl isobutyl ketone. It was dissolved to prepare a copolymer composition.
A glass cloth was impregnated with the obtained copolymer composition, and then dried by heating at 100° C. for about 3 minutes to prepare a prepreg. Specifically, the glass cloth is #1035 type manufactured by Asahi Kasei Corporation, E glass (density: 2.6 g/cm3, weight per 1 m2: 29.1 g, glass cloth thickness measurement value: 29 μm, dielectric constant measured value: 2.66, dielectric loss tangent measured value: 0.0048). At that time, the content of the copolymer composition (resin content) was adjusted to about 40% by mass.
Next, four sheets of the produced prepreg were superimposed and heated and pressed for 120 minutes under conditions of a temperature of 250° C. and a pressure of 2.44 MPa (megapascal) to prepare a specimen. The thickness of this specimen was 132.2 μm. As a result of measuring the dielectric constant and dielectric loss tangent of this specimen, the dielectric constant was 3.37, the dielectric loss tangent was 0.00522, and the gel fraction was 67%. The dielectric constant and dielectric loss tangent of the cured polymer were calculated from the measured values of the dielectric constant and dielectric loss tangent of the test body using the following equations.
Specimen dielectric loss tangent = glass cloth thread dielectric loss tangent x glass cloth vol%/100 + cured polymer dielectric loss tangent x cured polymer vol%/100
Glass cloth dielectric loss tangent = Glass cloth thread dielectric loss tangent x Glass cloth thread vol%/100 + Air dielectric loss tangent x Air vol%/100
Glass cloth vol% = Weight per 1 m ² of glass cloth/Glass cloth density/Thickness per prepreg sheet in test specimen after impregnation Cured polymer vol% = 1 - Glass cloth vol%

Claims (23)

A copolymer comprising an aromatic vinyl monomer unit, a cross-linking group-containing monomer unit, and a monomer unit giving a homopolymer having a glass transition temperature of 150°C or higher. A copolymer according to claim 1, which is a thermosetting resin. 3. The copolymer according to claim 1, wherein said aromatic vinyl monomer units are styrene units. 3. The copolymer according to claim 1, wherein the cross-linking group-containing monomer unit contains a diene monomer unit having an alicyclic structure. 3. The copolymer according to claim 1, wherein the cross-linking group-containing monomer unit contains a monomer unit having a dicyclopentenyl structure. 3. The copolymer according to claim 1, wherein the cross-linking group-containing monomer unit contains at least one selected from the group consisting of dicyclopentadiene units and dicyclopentenyl vinyl ether units. 3. The copolymer according to claim 1 or 2, wherein the monomer unit that provides the homopolymer having a glass transition temperature of 150°C or higher contains a maleimide group unit. 8. The copolymer according to claim 7, wherein said maleimide units include at least one selected from the group consisting of N-cyclohexylmaleimide units and N-phenylmaleimide units. 3. The copolymer according to claim 1, further comprising a fluorine-containing monomer unit providing a CF bond to the main chain. 3. The copolymer according to claim 1, which has a glass transition temperature of 140[deg.] C. or higher. 3. The copolymer according to claim 2, which has a thermosetting temperature of 240[deg.] C. or less. 3. The copolymer according to claim 1, which is soluble in methyl ethyl ketone or toluene. 3. The copolymer according to claim 1, wherein the cross-linking group-containing monomer unit accounts for 1 mol % or more of all polymerized units constituting the copolymer. 3. The copolymer according to claim 1, wherein the monomer units that give the homopolymer having a glass transition temperature of 150[deg.] C. or higher account for 5 mol % or more of all polymerized units constituting the copolymer. 3. The copolymer according to claim 1, which has a dielectric loss tangent of 0.0030 or less. A copolymer composition comprising the copolymer according to claim 1 or 2 and a solvent. 17. The copolymer composition according to claim 16, comprising a polymer containing a plurality of vinyl groups or a monomer component containing a plurality of vinyl groups. 17. The copolymer composition according to claim 16, which contains a photopolymerization initiator. 17. The copolymer composition according to claim 16, which has a gel fraction of 30% or more. A film comprising the copolymer of claim 1 or 2. A laminate comprising a substrate and a resin layer provided on the substrate, wherein the resin layer contains the copolymer according to claim 1 or 2. A metal-clad laminate comprising a metal foil and a resin layer provided on the metal foil, wherein the resin layer contains the copolymer according to claim 1 or 2. A printed circuit board comprising a pattern circuit formed by etching the metal foil of the metal-clad laminate according to claim 22.