TWI871640B - Resin composition, resin composition varnish and prepreg - Google Patents

Abstract

The present invention provides a resin composition for obtaining a printed wiring board having excellent dielectric properties, and a prepreg containing the composition. The resin composition of the present invention is characterized in that it comprises (A) a vinyl aromatic copolymer and (B) a polyphenylene ether, wherein the (A) vinyl aromatic copolymer has structural units derived from a divinyl aromatic compound and structural units derived from a monovinyl aromatic compound, wherein the ratio of the structural units derived from the monovinyl aromatic compound is 55 to 95 mol%, the ratio of the structural units derived from the divinyl aromatic compound is 5 to 45 mol%, and the number average molecular weight is 2000 to 8000, and the (B) polyphenylene ether has an OH group number of 20 to 900 μmol/g and a weight average molecular weight of 10,000 to 50,000.

Description

Resin composition, resin composition varnish and prepreg

The present invention relates to a resin composition, a resin composition varnish and a prepreg.

In recent years, with the significant progress of information network technology or the expansion of services using information networks, electronic equipment is required to have larger information capacity and faster processing speed. In order to respond to such requirements, in addition to the previously required insulation reliability, heat resistance, rigidity and flame retardancy, the printed wiring board mounted on the electronic equipment also strongly requires low dielectric constant and low dielectric loss factor. Therefore, research has been conducted on the main insulating materials that constitute the printed wiring board, namely the resin composition and the glass cloth substrate, especially on the further improvement of the dielectric loss factor.

As a resin composition, a polyphenylene ether (PPE) composition having a low dielectric constant, a dielectric dissipation factor, and high heat resistance is suitable for use as the above-mentioned printed wiring board material. For example, regarding the resin composition described in Patent Document 1, it is disclosed that if a specific modified PPE, a specific cyanurate compound as a crosslinking agent, a copolymer of butadiene and styrene, and an organic peroxide are contained in a specified ratio, the low dielectric constant and the low dielectric dissipation factor are excellent.

Furthermore, for example, Patent Document 2 discloses that in the preparation of a resin composition, if a polymer of an aromatic compound that does not contain impurity atoms is used, a resin composition having a lower dielectric constant and a lower dielectric loss factor can be obtained. [Prior Art Document] [Patent Document]

[Patent document 1] Japanese Patent Publication No. 2017-82200 [Patent document 2] International Publication No. 2017/115813

[The problem the invention is trying to solve]

However, in the case of polymers of aromatic compounds that do not contain impurities, there are major problems with brittleness or adhesion. As a resin composition that fully satisfies the main properties required for printed wiring boards, such as heat resistance, processability, moldability, and conductor adhesion, PPE compositions are currently mainly used. In addition, with the popularization of the fifth-generation mobile communication system (5G), the further reduction of the dielectric dissipation factor of PPE compositions with excellent property balance has become a problem. However, the currently widely used PPE that has been modified to a cross-linking functional group by lowering the molecular weight has the problem that the original dielectric properties of PPE are reduced due to the lower molecular weight.

Therefore, the object of the present invention is to provide a resin composition for obtaining a printed wiring board having excellent dielectric properties, and a prepreg containing the composition. [Technical means for solving the problem]

The inventors of the present invention have repeatedly conducted intensive research to solve the above-mentioned problems, and as a result, have found that the above-mentioned problems can be solved, thereby completing the present invention. That is, the present invention is as follows. [1] A resin composition, characterized in that it comprises the following components: (A) a vinyl aromatic copolymer, (B) a polyphenylene ether, wherein the above-mentioned (A) vinyl aromatic copolymer has structural units derived from divinyl aromatic compounds and structural units derived from monovinyl aromatic compounds, the ratio of structural units derived from monovinyl aromatic compounds is 55 to 95 mol%, the ratio of structural units derived from divinyl aromatic compounds is 5 to 45 mol%, and the number average molecular weight is 2000 to 8000, and the above-mentioned (B) polyphenylene ether has an OH group number of 20 to 900 μmol/g and a weight average molecular weight of 10,000 to 50,000. [2] The resin composition as described in [1], wherein the ratio of the component having a molecular weight of 1000 or less as determined by gel permeation chromatography area value in the above-mentioned (A) vinyl aromatic copolymer is 1 to 30%. [3] The resin composition as described in [1] or [2], wherein the boron content of the above-mentioned (A) vinyl aromatic copolymer is 0.5 to 5 ppm. [4] The resin composition as described in any one of [1] to [3], wherein the above-mentioned (B) polyphenylene ether contains 5 to 90 mol% of the repeating units derived from the phenol of the following formula (1) and 10 to 95 mol% of the repeating units derived from the phenol of the following formula (2), relative to 100 mol% of the total of the repeating units derived from the phenol of the following formula (1) and the repeating units derived from the following formula (2). [Chemical 1] (In formula (1), R ¹¹ is independently a saturated alkyl group having 1 to 6 carbon atoms which may be substituted, an aryl group having 6 to 12 carbon atoms which may be substituted, or a halogen atom, and R ¹² is independently a hydrogen atom, a alkyl group having 1 to 6 carbon atoms which may be substituted, an aryl group having 6 to 12 carbon atoms which may be substituted, or a halogen atom.) [Chemistry 2] {In formula (2), R ²² is independently a hydrogen atom, a saturated or unsaturated alkyl group having 1 to 20 carbon atoms which may be substituted, an aryl group having 6 to 12 carbon atoms which may be substituted, or a halogen atom, and two R ²² are not hydrogen atoms at the same time, and R ²¹ is a partial structure represented by the following formula (3). [Chemistry 3] (In formula (3), R ³¹ is independently a linear alkyl group having 1 to 8 carbon atoms which may be substituted, or a cyclic alkyl group having 1 to 8 carbon atoms to which two R ³¹ are bonded, R ³² is independently an alkylene group having 1 to 8 carbon atoms which may be substituted, b is independently 0 or 1, and R ³³ is a hydrogen atom, an alkyl group having 1 to 8 carbon atoms which may be substituted, or a phenyl group which may be substituted)}. [5] A resin composition varnish comprising a resin composition as described in any one of [1] to [4] and an aromatic solvent. [6] A prepreg comprising a resin composition as described in any one of [1] to [4], a substrate and an aromatic solvent, and comprising 0.1 to 1.0 wt % of an aromatic solvent. [Effect of the invention]

According to the present invention, a resin composition for obtaining a printed wiring board having excellent dielectric properties and a prepreg containing the composition can be provided.

The following is a description of a method for implementing the present invention (hereinafter referred to as "this embodiment"). Since the following embodiment is one aspect of the present invention, the present invention is not limited to the following embodiment. Therefore, the following embodiment can be implemented by appropriately changing it within the scope of the subject matter of the present invention. In addition, unless otherwise specified, "to" in this specification refers to the numerical values including both ends as the upper limit and the lower limit. In this specification, the upper limit and the lower limit of the numerical range can be arbitrarily combined.

The resin composition of the present embodiment is a composition comprising (A) a vinyl aromatic copolymer and (B) a polyphenylene ether. The vinyl aromatic copolymer (A) has structural units derived from divinyl aromatic compounds and structural units derived from monovinyl aromatic compounds, the ratio of structural units derived from monovinyl aromatic compounds is 55-95 mol%, the ratio of structural units derived from divinyl aromatic compounds is 5-45 mol%, and the number average molecular weight is 2000-8000. The polyphenylene ether (B) has an OH group number of 20-900 μmol/g and a weight average molecular weight of 10000-50000.

[(A) Vinyl aromatic copolymer] The (A) vinyl aromatic copolymer (hereinafter, sometimes referred to as "copolymer") of the present embodiment is a copolymer having structural units derived from a divinyl aromatic compound and structural units derived from a monovinyl aromatic compound, wherein the ratio of the structural units derived from the monovinyl aromatic compound is 55 to 95 mol%, the ratio of the structural units derived from the divinyl aromatic compound is 5 to 45 mol%, and the number average molecular weight is 2000 to 8000.

For the copolymer, by making the ratio of the structural unit derived from monovinylbenzene to be 55 mol% or more, compatibility with PPE, fluidity during vacuum pressure molding, and low dielectric loss factor of the substrate can be obtained. By making the ratio of the structural unit derived from monovinylbenzene to be 95 mol% or less, low dielectric loss factor structural units other than monovinylbenzene, cross-linking structural units, etc. can be introduced into the copolymer. From this point of view, the ratio of the structural unit derived from monovinylbenzene is preferably 55-95 mol%, and more preferably 65-85 mol%.

For the copolymer, by making the ratio of the structural unit derived from divinylbenzene to be 5 mol% or more, compatibility with PPE, heat resistance of the substrate, high Tg, and low dielectric loss factor can be obtained. By making the ratio of the structural unit derived from divinylbenzene to be 45 mol% or less, gelation and localization can be prevented during the curing of the resin composition, and the impregnation in the glass cloth when making a laminate can be improved. From this point of view, the ratio of the structural unit derived from divinylbenzene is preferably 5 to 45 mol%, and more preferably 10 to 35 mol%.

For the copolymer, by making the number average molecular weight above 2000, volatility can be controlled when the resin composition is coated on the glass cloth substrate, and a product with stable characteristics can be obtained. By making the number average molecular weight below 8000, there will be no adverse effect on solvent solubility, PPE compatibility or fluidity during vacuum pressure molding. From this point of view, the number average molecular weight (Mn) of the copolymer is preferably 2000-8000, more preferably 2500-7000, and further preferably 3000-6000.

For copolymers, by making the amount of components with a molecular weight of less than 1000 to be 1% or more (GPC (Gel Permeation Chromatography) area value), there is a tendency as follows: after the resin composition is applied to the glass cloth substrate and dried, the amount of resin powder falling off of the prepreg can be suppressed, cracks during the heat resistance test after the substrate is formed can be prevented, and the insulation reliability between the insulating layers can be improved. By making the amount of components with a molecular weight of less than 1000 to be 30% or less (GPC area value), there is a tendency to suppress the amount of resin powder falling off, and to suppress the hardening resistance during the substrate molding and the reduction of the substrate Tg. From this point of view, the amount of components with a molecular weight of less than 1000 in the copolymer is preferably 1 to 30% (GPC area value). The amount of this component is more preferably 1 to 20%, and further preferably 1 to 10%.

For the copolymer, the monovinylbenzene monomer content is preferably 0.01 to 5.0 mol%. When it is 0.01 mol% or more, the amount of resin powder falling off the prepreg surface after prepreg molding can be suppressed, and the fluidity during vacuum pressure molding can be improved. When it is 5.0 mol% or less, the decrease in substrate Tg can be suppressed and the storage stability of the prepreg can be improved.

For copolymers, by making the boron content 0.5 ppm or more, there is a tendency that the interfacial adhesion with a low dielectric glass cloth substrate containing a large amount of boron components is improved, and the adhesion, which is a common problem of hydrocarbon polymers, can be improved. By making it less than 5 ppm, the water absorption of the substrate can be suppressed. Regarding the boron content, it tends to be possible to use a boron compound in a polymerization catalyst, for example, and prepare the boron content by purification. From this point of view, the boron content of the copolymer is preferably 0.5 to 5 ppm, and more preferably 0.5 to 3 ppm.

In the present embodiment, examples of monovinylbenzene constituting the copolymer include styrene, ethylvinylbenzene, ethylvinylnaphthalene, ethylvinylbiphenyl, etc. Examples of divinylbenzene constituting the copolymer include divinylbenzene, divinylnaphthalene, divinylbiphenyl, etc. Among them, styrene and divinylbenzene are most preferred from the viewpoint of compatibility with PPE.

Furthermore, within the range that does not impair the copolymer characteristics of the present embodiment, copolymerizable monomers other than monovinylbenzene and divinylbenzene may be introduced, for example, cyclic olefin compounds such as northene, ethylidene northene, cyclopentadiene, dicyclopentadiene, indene, and acenaphthene.

The molecular weight distribution (Mw/Mn) represented by the ratio of the weight average molecular weight (Mw) to the number average molecular weight (Mn) of the copolymer is preferably 2.5 or less. By making Mw/Mn 2.5 or less, there will be no adverse effect on solvent solubility, PPE compatibility or fluidity during vacuum pressure molding. From this point of view, the Mw/Mn of the copolymer is more preferably 1 or more and 2.0 or more than 1 and less than 2.0.

As a method for producing the copolymer of this embodiment, a known polymerization method can be adopted, which uses the monovinylbenzene, divinylbenzene, and monomers copolymerizable therewith as described above, for example, cationic polymerization, anionic polymerization, free radical polymerization, and coordination polymerization can be used alone or in combination. Regarding a specific synthesis of this embodiment, reference can be made to the method described in the Examples.

The amount of the copolymer in the resin composition of the present embodiment is 5-70% by mass relative to the total amount of the copolymer and PPE. From the viewpoint of compatibility with other components, or from the viewpoint of reduced dielectric loss factor, improved heat resistance and good appearance of a molded body of the resin composition, a prepreg including the resin composition, a laminate of a plurality of prepregs, a laminate of a prepreg and a substrate, etc., the amount of the copolymer is preferably 10-50% by mass, more preferably 15-40% by mass.

[(B) Polyphenylene ether] In this embodiment, a resin composition comprising (B) polyphenylene ether is provided. (B) Polyphenylene ether comprises a phenylene ether unit as a repeating structural unit. The phenylene group in the phenylene ether unit may or may not have a substituent.

Furthermore, the polyphenylene ether (B) of the present embodiment contains at least a repeating unit derived from a phenol of the following formula (1) and a repeating unit derived from a phenol of the following formula (2). The repeating unit in the compound may also be composed only of a repeating unit derived from a phenol of the following formula (1) and a repeating unit derived from a phenol of the following formula (2). [Chemistry 4] (In formula (1), R ¹¹ is independently a saturated alkyl group having 1 to 6 carbon atoms which may be substituted, an aryl group having 6 to 12 carbon atoms which may be substituted, or a halogen atom, and R ¹² is independently a hydrogen atom, a alkyl group having 1 to 6 carbon atoms which may be substituted, an aryl group having 6 to 12 carbon atoms which may be substituted, or a halogen atom.) [Chemistry 5] {In formula (2), R ²² is independently a hydrogen atom, a saturated or unsaturated alkyl group having 1 to 20 carbon atoms which may be substituted, an aryl group having 6 to 12 carbon atoms which may be substituted, or a halogen atom, and two R ²² are not hydrogen atoms at the same time, and R ²¹ is a partial structure represented by the following formula (3). [Chemistry 6] (In formula (3), R ³¹ is independently a linear alkyl group having 1 to 8 carbon atoms which may be substituted, or a cyclic alkyl group having 1 to 8 carbon atoms to which two R ³¹ are bonded, R ³² is independently an alkylene group having 1 to 8 carbon atoms which may be substituted, b is independently 0 or 1, and R ³³ is a hydrogen atom, an alkyl group having 1 to 8 carbon atoms which may be substituted, or a phenyl group which may be substituted)}.

In the above formula (1), R ¹¹ is independently preferably a saturated alkyl group having 1 to 6 carbon atoms or an aryl group having 6 to 12 carbon atoms, more preferably a methyl group or a phenyl group, and still more preferably a methyl group. In the formula (1), two R ^11s are preferably of the same structure. As a substituent in the saturated alkyl group having 1 to 6 carbon atoms or the aryl group having 6 to 12 carbon atoms of the above R ¹¹ , there can be mentioned: a saturated or unsaturated alkyl group having 1 to 10 carbon atoms, an aryl group having 6 to 10 carbon atoms, and a halogen atom.

In the above formula (1), R ¹² is independently preferably a hydrogen atom or a alkyl group having 1 to 6 carbon atoms, more preferably a hydrogen atom or a methyl group. In the formula (1), it is preferred that the two R ¹² are different, and it is more preferred that one of them is a hydrogen atom and the other is a alkyl group having 1 to 6 carbon atoms (preferably a methyl group). As a substituent in the alkyl group having 1 to 6 carbon atoms and the aryl group having 6 to 12 carbon atoms in the above R ¹² , there can be mentioned: a saturated or unsaturated alkyl group having 1 to 10 carbon atoms, an aryl group having 6 to 10 carbon atoms, and a halogen atom.

In the above formula (2), R ²² is preferably independently a hydrogen atom, a saturated or unsaturated alkyl group having 1 to 15 carbon atoms, or an aryl group having 6 to 12 carbon atoms which may be substituted by an alkyl group having 1 to 6 carbon atoms, more preferably a hydrogen atom, a alkyl group having 1 to 6 carbon atoms, or an aryl group having 6 to 10 carbon atoms which may be substituted by an alkyl group having 1 to 6 carbon atoms, and further preferably a hydrogen atom or a methyl group. In formula (2), it is preferred that the two R ²² are different, and it is more preferred that one of them is a hydrogen atom and the other is a alkyl group having 1 to 6 carbon atoms (preferably a methyl group). Examples of the substituent in the saturated or unsaturated alkyl group having 1 to 20 carbon atoms or the aryl group having 6 to 12 carbon atoms represented by R ²² include a saturated or unsaturated alkyl group having 1 to 10 carbon atoms, an aryl group having 6 to 10 carbon atoms, and a halogen atom.

As the partial structure represented by the above formula (3), a group containing secondary and/or tertiary carbon is preferred, for example, isopropyl, isobutyl, sec-butyl, t-butyl, t-pentyl, 2,2-dimethylpropyl, cyclohexyl, or a structure having a phenyl group at the end thereof, more preferably t-butyl and cyclohexyl, and further preferably t-butyl. Furthermore, as the substituent in the linear alkyl group having 1 to 8 carbon atoms of the above R ³¹ , the substituent in the alkylene group having 1 to 8 carbon atoms of the above R ³² , and the substituent in the alkyl group having 1 to 8 carbon atoms and the phenyl group of the above R ³³ , saturated or unsaturated alkyl groups having 1 to 10 carbon atoms, aryl groups having 6 to 10 carbon atoms, and halogen atoms are exemplified.

In this embodiment, the structure of polyphenylene ether can be identified by analyzing it using NMR (Nuclear Magnetic Resonance), mass spectrometry, and the like. As a specific method for identifying the structure of polyphenylene ether, field desorption mass spectrometry (FD-MS), which is known to be less likely to cause fragmentation, can be performed, and the repeating unit can be estimated based on the interval of the detected ions. Further, the following method can be cited: the structure of polyphenylene ether can be estimated by combining it with fragment ion peak analysis using electron ionization (EI) or structural analysis using NMR.

The polyphenylene ether of the present embodiment preferably contains 5 to 90 mol% of the repeating units derived from the phenol of formula (1) and 10 to 95 mol% of the repeating units derived from the phenol of formula (2), relative to a total of 100 mol% of the repeating units derived from the phenol of formula (1) and the repeating units derived from the phenol of formula (2). From the viewpoint of obtaining a polyphenylene ether having excellent solvent solubility and a low dielectric loss factor, the repeating units derived from the phenol of formula (2) are preferably 15 mol% or more, more preferably 20 mol% or more. From the same viewpoint, the repeating units derived from the phenol of formula (1) are preferably 85 mol% or less, more preferably 80 mol% or less. The polyphenylene ether of this embodiment may contain one or more repeating units derived from the phenol of formula (1). In addition, the polyphenylene ether of this embodiment may contain one or more repeating units derived from the phenol of formula (2).

With respect to 100 mol % of the monomer units contained in the polyphenylene ether of the present embodiment (for example, all monomer units derived from phenol contained in the polyphenylene ether), the total molar amount of the repeating units derived from the phenol of formula (1) and the repeating units derived from the phenol of formula (2) is preferably 75 mol % or more, more preferably 90 mol % or more, and even more preferably 95 mol % or more.

The ratio of the repeating units derived from the phenol of formula (1) to the repeating units derived from the phenol of formula (2) can be determined, for example, by analytical methods such as ¹ H-NMR and ¹³ C-NMR. More specifically, it can be measured by the method described in the Examples below.

Since the phenol of formula (1) has no unsubstituted adjacent positions (i.e., since there is no hydrogen atom bonded to the two adjacent carbon atoms of the carbon atom to which the hydroxyl group is bonded), it can only react with another phenolic monomer at the phenolic hydroxyl group and the para carbon atom. Therefore, the repeating unit derived from formula (1) includes a repeating unit having the structure of the following formula (8). [Chemistry 7] (In formula (8), R ¹¹ and R ¹² are the same as in formula (1)).

In addition to the phenolic hydroxyl group, the phenol of formula (2) can also react with another phenolic monomer at any position of the ortho-position or para-position of the phenol. Therefore, the repeating unit derived from the phenol of formula (2) has a monomer unit of the following formula (9), the following formula (10) or a combination thereof. [Chemistry 8] [Chemistry 9] (R ²¹ and R ²² in formula (9) and formula (10) are the same as those in formula (2)).

The OH number of the polyphenylene ether in this embodiment is 20 to 900 μmol/g. By making the OH number less than 900 μmol/g, the compatibility with the (A) vinyl aromatic copolymer is improved, and the heat resistance, Tg, and dielectric loss factor of the substrate can be obtained. The OH number is preferably less than 700 μmol/g, and more preferably less than 500 μmol/g. In addition, by making the OH number of the polyphenylene ether greater than 20 μmol/g, the adhesion with copper and the like is improved, and the stability of the synthesis tends to be improved. The OH number is preferably greater than 50 μmol, and more preferably greater than 100 μmol. The weight average molecular weight of the polyphenylene ether in this embodiment is 10,000 to 50,000. By making the weight average molecular weight above 10,000, high heat resistance, Tg and low dielectric dissipation factor can be obtained due to the PPE structure. By making the weight average molecular weight below 50,000, solubility in solvents and resin fluidity during substrate molding can be maintained. On the other hand, compared with low molecular weight end-modified PPE, crosslinking and resin fluidity are reduced, so a combination with the above copolymer is required. The weight average molecular weight of PPE is preferably 15,000 to 40,000, and more preferably 20,000 to 35,000.

The polyphenylene ether in the present embodiment may contain, in addition to the phenol of formula (1) and the phenol of formula (2), a terpolymer having a structure derived from the dihydric phenol of the following formula (11) as an impurity (sometimes referred to as "impurity A" in this specification). The polyphenylene ether in the present embodiment may also be a mixture of the above polyphenylene ether and the above impurity A. The molar ratio of the impurity A relative to 100 mole % of the polyphenylene ether in the present embodiment is preferably 10 mole % or less, and more preferably 5 mole % or less.

The impurity A can be synthesized into a terpolymer containing a structure of a dihydric phenol with z=0 from the formula (11) by reacting the following formula (12) produced as a byproduct during the oxidative polymerization of a monohydric phenol with a polyphenylene ether containing a monohydric phenol. [Chemistry 10] {In formula (11), R ¹¹ and R ¹² are the same as those in formula (1). z is 0 or 1, and Y is any one of the following: [Chemical 11] (wherein, R ⁴¹ is independently any one of a substituted alkyl group having 1 to 6 carbon atoms, a substituted aryl group having 6 to 12 carbon atoms, and a halogen atom)}. [Chemical 12] (In formula (12), R ¹¹ and R ¹² are the same as in formula (1)).

The average hydroxyl group number of the polyphenylene ether in the present embodiment is preferably less than 3.0 per molecule, more preferably less than 2.5 per molecule, and even more preferably less than 2.0 per molecule in the case of unmodified polyphenylene ether. When the average hydroxyl group number exceeds 3.0 per molecule, it means that the polyphenylene ether is a multi-branched unmodified polyphenylene ether whose structure cannot be controlled.

The polyphenylene ether in the present embodiment may also be a modified polyphenylene ether in which the hydroxyl groups contained in the polyphenylene ether are modified into functional groups (e.g., functional groups containing unsaturated carbon bonds, etc.). In the case of the modified polyphenylene ether, the average number of hydroxyl groups is preferably less than 0.2 per molecule, more preferably less than 0.1 per molecule, and even more preferably less than 0.01 per molecule.

The polyphenylene ether in this embodiment may have at least one partial structure selected from the group consisting of the following formula (4), formula (5), formula (6) and formula (7). [Chemistry 14] [Chemistry 15] (In formula (6), ^R6 is a hydrogen atom or a saturated or unsaturated hydrocarbon group having 1 to 10 carbon atoms, and the saturated or unsaturated hydrocarbon group may have a substituent within the range of 1 to 10 carbon atoms in total of ^R6 .) [Chemistry 16] (In formula (7), ^R7 is a saturated or unsaturated divalent hydrocarbon group having 1 to 10 carbon atoms, and the saturated or unsaturated divalent hydrocarbon group may have a substituent within the range of 1 to 10 carbon atoms in total of ^R7 ; ^R8 is a hydrogen atom or a saturated or unsaturated hydrocarbon group having 1 to 10 carbon atoms, and the saturated or unsaturated hydrocarbon group may have a substituent within the range of 1 to 10 carbon atoms in total of ^R8 ).

Furthermore, at least one partial structure selected from the group consisting of the above formula (4), formula (5), formula (6) and formula (7) can be directly bonded to the hydroxyl group contained in the polyphenylene ether.

The polyphenylene ether in the present embodiment may also contain a monohydric phenol having at least one unsaturated hydrocarbon group at the adjacent carbon atom of the carbon atom to which the hydroxyl group of phenol is bonded. With respect to the above-mentioned monohydric phenol, the number of unsaturated hydrocarbon groups bonded to the adjacent carbon atom of the carbon atom to which the hydroxyl group of phenol is bonded is preferably one. The above-mentioned unsaturated hydrocarbon group may be bonded one by one to the two adjacent carbon atoms of the carbon atom to which the hydroxyl group of the above-mentioned monohydric phenol is bonded, or one unsaturated hydrocarbon group may be bonded to one of the adjacent carbon atoms. Furthermore, the above-mentioned monohydric phenol having at least one unsaturated hydrocarbon group at the adjacent carbon atom of the carbon atom to which the hydroxyl group of phenol is bonded refers to a monohydric phenol different from the phenol of the above-mentioned formula (1) or the phenol of the above-mentioned formula (2).

As the unsaturated hydrocarbon group, an unsaturated hydrocarbon group having 3 to 10 carbon atoms is preferred, and an unsaturated hydrocarbon group having 3 to 5 carbon atoms is preferred. Examples of such unsaturated hydrocarbon groups include alkenyl (e.g., vinyl, allyl, etc.), alkynyl (e.g., ethynyl, 1-propynyl, 2-propynyl, etc.), etc. The above unsaturated hydrocarbon group may have a substituent as long as the condition of having 3 to 10 carbon atoms is satisfied.

The introduction rate of the monohydric phenol having at least one unsaturated alkyl group at the carbon atom adjacent to the carbon atom to which the hydroxyl group of the phenol is bonded can be appropriately adjusted to adjust the number of curable functional groups. The monohydric phenol having at least one unsaturated alkyl group at the carbon atom adjacent to the carbon atom to which the hydroxyl group of the phenol is bonded is preferably 0.1 to 30 mol %, more preferably 0.1 to 25 mol %, relative to the total of the phenol of formula (1) and the monohydric phenol having at least one unsaturated alkyl group at the carbon atom adjacent to the carbon atom to which the hydroxyl group of the phenol is bonded.

With respect to the total of the repeating units derived from the phenol of formula (1) and the repeating units derived from the monophenol having at least one unsaturated hydrocarbon group at the carbon atom adjacent to the carbon atom to which the hydroxyl group of the phenol is bonded in the polyphenylene ether of the present embodiment, the molar ratio of the repeating units derived from the monophenol having at least one unsaturated hydrocarbon group at the carbon atom adjacent to the carbon atom to which the hydroxyl group of the phenol is bonded is preferably 0.1 to 40 mol%, more preferably 0.1 to 10 mol%.

Furthermore, the PPE contained in the resin composition may be one kind or a combination of two or more kinds of PPE.

The amount of PPE in the resin composition of the present embodiment is 30-95% by mass relative to the total amount of the copolymer and PPE. From the viewpoint of compatibility with other components, or from the viewpoint of reduced dielectric loss factor, improved heat resistance and good appearance of a molded body of the resin composition, a prepreg including the resin composition, a laminate of a plurality of prepregs, a laminate of a prepreg and a substrate, etc., the amount of PPE is preferably 50-90% by mass, and more preferably 60-85% by mass.

[Additives] In this embodiment, a common crosslinking agent may be added to the resin composition within the range that does not impair the properties. For example, a triallyl isocyanurate compound such as triallyl isocyanurate (TAIC) and/or a triallyl cyanurate compound such as triallyl cyanurate (TAC) will further improve the compatibility between PPE and styrene copolymers, and further improve the heat resistance or conductor adhesion of the laminate. In addition to isocyanuric acid trialenyl ester/cyanuric acid trialenyl ester, for example, there are also: multifunctional methacrylate compounds having two or more methacrylic groups in the molecule, multifunctional acrylate compounds having two or more acryl groups in the molecule, multifunctional vinyl compounds having two or more vinyl groups in the molecule such as polybutadiene, and multifunctional maleimide compounds having two or more maleimide groups in the molecule such as 4,4'-bismaleimide diphenylmethane. In addition, examples of the thermoplastic resin include styrene-butadiene block copolymers, styrene-ethylene-butadiene block copolymers, styrene-ethylene-butylene block copolymers, styrene-butadiene-butylene block copolymers, styrene-isoprene block copolymers, styrene-ethylene-propylene block copolymers, styrene-isobutylene block copolymers, hydrogenated styrene-butadiene block copolymers, hydrogenated styrene-ethylene-butadiene block copolymers, hydrogenated styrene-butadiene-butylene block copolymers, hydrogenated styrene-isoprene block copolymers, and homopolymers of styrene (polystyrene). More preferably, at least one selected from the group consisting of styrene-butadiene block copolymers, hydrogenated styrene-butadiene block copolymers, and polystyrene. The weight average molecular weight of the thermoplastic resin is preferably 30,000 to 300,000, more preferably 31,000 to 290,000. The weight average molecular weight is a value obtained by using a gel permeation chromatograph and converting it to standard polystyrene.

[Organic peroxide] In the present embodiment, any organic peroxide capable of promoting the polymerization reaction of the resin composition can be used. Examples of the organic peroxide include: benzoyl peroxide, cumene hydroperoxide, 2,5-dimethylhexane-2,5-dihydroperoxide, 2,5-dimethyl-2,5-di(tert-butylperoxy)hexyne-3, di-tert-butyl peroxide, tert-butyl isopropyl peroxide, di(2-tert-butylperoxyisopropyl)benzene, 2,5-dimethyl-2,5-di(tert-butylperoxyisopropyl)benzene, Peroxides such as 2,5-dimethyl-2,5-di(benzoylperoxy)hexane, diisopropyl peroxide, di-tert-butyl peroxyisophthalate, tert-butyl peroxybenzoate, 2,2-bis(tert-butylperoxy)butane, 2,2-bis(tert-butylperoxy)octane, 2,5-dimethyl-2,5-di(benzoylperoxy)hexane, di(trimethylsilyl)peroxide, trimethylsilyltriphenylsilylperoxide, etc. Free radical generators such as 2,3-dimethyl-2,3-diphenylbutane can also be used as reaction initiators for the resin composition. Among them, from the perspective of providing a cured product with excellent heat resistance and mechanical properties, and thus having a low dielectric constant and a low dielectric dissipation factor, 2,5-dimethyl-2,5-di(tert-butylperoxy)hexyne-3, di(2-tert-butylperoxyisopropyl)benzene, and 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane are preferred.

The 1-minute half-life temperature of the organic peroxide is preferably 155°C to 185°C, or 160°C to 180°C, or 165°C to 175°C. In this specification, the 1-minute half-life temperature is the temperature at which the amount of active oxygen in the organic peroxide decomposes and is reduced by half in 1 minute. The 1-minute half-life temperature is a value confirmed by the following method, that is, the organic peroxide is dissolved in a solvent inert to free radicals such as benzene at a concentration of 0.05 mol/L to 0.1 mol/L, and the organic peroxide solution is thermally decomposed in a nitrogen atmosphere.

By setting the one-minute half-life temperature of the organic peroxide to be above 155°C, when the resin composition is subjected to heat and pressure molding, the reaction with the crosslinking agent can be started after the PPE is fully melted, so there is a tendency for excellent moldability. On the other hand, by setting the one-minute half-life temperature of the organic peroxide to be below 185°C, the decomposition rate of the organic peroxide under normal heat and pressure molding conditions (e.g., the maximum limit temperature of 200°C) is sufficient, so the crosslinking reaction with the crosslinking agent can be carried out efficiently and smoothly, thereby forming a cured product with good electrical properties (especially dielectric loss factor).

Examples of organic peroxides having a half-life temperature within the range of 155°C to 185°C include tert-hexyl peroxyisopropyl monocarbonate (155.0°C) (the temperature within the brackets is the half-life temperature within 1 minute, the same below), tert-butyl peroxy-3,5,5-trimethylhexanoate (166.0°C), tert-butyl peroxylaurate (159.4°C), tert-butyl peroxyisopropyl monocarbonate (158.8°C), tert-butyl peroxy-2-ethylhexyl monocarbonate (161.4°C), tert-hexyl peroxybenzoate (160.3°C), 2,5-dimethyl-2,5-di(benzoylperoxy)hexane (158.2°C), t-butyl peroxyacetate (159.9°C), 2,2-di-(t-butylperoxy)butane (159.9°C), t-butyl peroxybenzoate (166.8°C), n-butyl 4,4-di-(t-butylperoxy)valerate (172.5°C), di(2-t-butylperoxyisopropyl)benzene (175.4°C), diisopropylphenyl peroxide (175.2°C), di-t-hexyl peroxide (176.7°C), 2,5-dimethyl-2,5-di(t-butylperoxy)hexane (179.8°C), and t-butylisopropylphenyl peroxide (173.3°C).

The content of the organic peroxide is preferably 0.05% by mass or more, more preferably 0.1% by mass or more, more preferably 0.3% by mass or more, and more preferably 0.5% by mass or more, based on the total mass of the resin composition as 100% by mass, from the viewpoint of increasing the reaction rate, and preferably 3% by mass or less, more preferably 2% by mass or less, and more preferably 1% by mass or less, from the viewpoint of suppressing the dielectric constant and dielectric dissipation factor of the obtained cured product to a lower level. [Flame retardant] The resin composition preferably contains a flame retardant. As flame retardants, for example, inorganic flame retardants such as antimony trioxide, aluminum hydroxide, magnesium hydroxide and zinc borate; aromatic bromine compounds such as hexabromobenzene, decabromodiphenylethane, 4,4-dibromobiphenyl, ethyl bis(tetrabromophthalimide); phosphorus-based flame retardants such as resorcinol bis(diphenyl phosphate) and resorcinol bis(xylyl phosphate), etc. These flame retardants can be used alone or in combination of two or more. Among them, from the perspective of low dielectric constant and low dielectric dissipation factor when the resin composition is cured, the flame retardant is preferably decabromodiphenylethane.

The content of the flame retardant is not particularly limited. From the perspective of maintaining the flame retardancy of UL (Underwriters Laboratories) specification 94V-0 level, it is preferably 5 parts by mass or more, more preferably 10 parts by mass or more, and further preferably 15 parts by mass or more, relative to 100 parts by mass of the total resin composition. In addition, from the perspective of maintaining the dielectric constant and dielectric dissipation factor of the obtained cured product at a low level, the content of the flame retardant is preferably 50 parts by mass or less, more preferably 45 parts by mass or less, and further preferably 40 parts by mass or less.

[Silica filler] The resin composition may contain a silica filler. As the silica filler, any of natural silica and synthetic silica may be used, for example, fused silica, amorphous silica, Aerosil and hollow silica. The content of the silica filler may be 10 to 100 parts by mass relative to 100 parts by mass of the total of PPE and all components that can be used as a crosslinking agent. In addition, the silica filler may be one whose surface has been treated with a silane coupling agent or the like.

In addition to the above ingredients, the resin composition may further include additives such as a heat stabilizer, an antioxidant, a UV (ultraviolet) absorber, a surfactant, a lubricant, etc.

<Resin composition varnish> From the perspective of obtaining better fluidity when impregnated into a glass cloth substrate, the resin composition can be made into a resin composition varnish containing a solvent. In the manufacturing step of the prepreg, it is preferred to impregnate the resin composition varnish into the glass cloth substrate and then dry it with a hot air dryer to remove the solvent. The solid components in the resin composition can be dissolved or dispersed in the varnish. The amount of solvent can be appropriately adjusted so that the fluidity of the resin composition varnish is within a better range. For example, the amount of solvent in the resin composition varnish can be 20 to 80% by mass, or 30 to 70% by mass, or 40 to 60% by mass.

As the solvent, from the viewpoint of solubility of the components in the resin composition, aromatic compounds such as toluene and xylene, methyl ethyl ketone, cyclopentanone, cyclohexanone and chloroform are preferred. These solvents may be used alone or in combination of two or more.

From the viewpoint of ensuring the better fluidity of the resin composition varnish at room temperature, it is preferable to use an aromatic compound including toluene as a solvent, for example, a toluene-methyl ethyl ketone mixed solvent, a toluene-cyclohexanone mixed solvent, and a toluene-cyclopentanone mixed solvent. In addition, if it is the resin composition of the present embodiment, even if it is a solvent of toluene alone, it can be well dissolved in the solvent, and further, the impregnation property in the substrate is also excellent, so as a solvent, it is also preferable to use a solvent of toluene alone. Furthermore, if the content of the aromatic compound solvent in the prepreg is 0.1 to 1.0 wt%, the powder falling of the prepreg can be suppressed, and the hardening resistance can also be suppressed. More preferably, it is 0.1 to 0.5 wt%.

<Laminate> This embodiment also provides a prepreg, and a laminate (laminate) obtained by using a plurality of the prepregs as needed (specifically, a metal-clad laminate), wherein the prepreg is obtained by impregnating a glass cloth formed of E glass fiber, L glass fiber, S glass fiber, quartz glass fiber, etc., or an organic fiber cloth formed of aromatic polyamide resin fiber, etc., as a substrate, into the resin composition of this embodiment. The dielectric dissipation factor of the laminate is preferably less than 0.0033, and more preferably less than 0.0031, when measured at 10 GHz by the method described in the embodiment. The metal-clad laminate is obtained by laminating and curing the prepreg of the present embodiment and the metal foil. The metal-clad laminate is preferably in a form in which the cured product of the prepreg (also referred to as a "cured product composite") and the metal foil are laminated and in close contact, and is suitable for use as a material for electronic circuit boards. Examples of the metal foil include aluminum foil and copper foil, among which copper foil is preferred because of its lower electrical resistance. The cured product composite combined with the metal foil may be a single sheet or a plurality of sheets, and the metal foil is overlapped on one or both sides of the composite to form a laminate according to the application. As a method for manufacturing a laminate, for example, the following method can be cited: forming the above-mentioned prepreg, stacking the prepreg and the metal foil, and then hardening the resin composition to obtain a laminate having a hardened laminate and a metal foil. One of the preferred uses of the laminate is a printed wiring board. The printed wiring board is preferably a self-clad metal laminate with at least a portion of the metal foil removed.

<Printed wiring board> The printed wiring board of this embodiment is formed by removing a portion of the metal foil from the metal-clad laminate. The printed wiring board of this embodiment is typically formed by a pressurized heat molding method using the prepreg of the above-mentioned embodiment. The printed wiring board of this embodiment is made of the prepreg of this embodiment, and thus has excellent heat resistance and electrical properties (low dielectric constant and low dielectric dissipation factor), and can suppress changes in electrical properties accompanying environmental changes, thereby having excellent insulation reliability and mechanical properties. [Example]

The following examples are given to illustrate the present embodiment in detail. However, the present embodiment is not limited to the examples.

[Materials] The following materials are used.

(Copolymer) For the 6 combinations in Table 1, the components listed in Table 1 were mixed with propyl acetate at [propyl acetate]/[monomer]=0.95 (mol ratio). Boron trifluoride diethyl ether complex [catalyst]/[monomer]=0.038 (mol ratio) was added as a catalyst. After heating at 70°C for 30 minutes and polymerization, a saturated sodium bicarbonate aqueous solution was added to stop the polymerization, and then concentrated with an evaporator to obtain 10 (co)polymers. The monomers used are shown below. ・St: Styrene ・DVB: Divinylbenzene ・EVB: Ethylvinylbenzene

[Table 1] Copolymer A B C D E F Use single St 70 55 70 70 97 50 DVB 30 30 30 30 3 50 EVB 0 15 0 0 0 0 Copolymer Properties Content of components with molecular weight below 1000 3 3 0.5 35 5 2 Number average molecular weight 4500 3800 6500 2000 4500 6500 Molecular weight distribution (Mw/Mn) 2.0 2.1 1.6 2.5 2.0 3.0

(Determination method of the ratio of each structural unit of vinyl aromatic copolymer) The measurement was performed by ¹³ C-NMR and ¹ H-NMR analysis using a nuclear magnetic resonance spectrometer manufactured by JEOL Ltd. (model name: JNM-ECZ500R/S1). Chloroform-d1 was used as a solvent, and the resonance line of tetramethylsilane was used as an internal standard. The ratio of the peak area values at 5.2 ppm and 5.7 ppm to the peak area value at 5.8 ppm to 7.7 ppm was taken as the ratio of the structural unit (a) derived from the divinyl aromatic compound, and the value obtained by subtracting the ratio of the structural unit (a) derived from the divinyl aromatic compound from 1 was taken as the ratio of the structural unit (b) derived from the monovinyl aromatic compound.

(Determination method of molecular weight distribution of vinyl aromatic copolymer) Using gel permeation chromatography (GPC), the number average molecular weight (Mn) of styrene-based elastomer is determined by comparing the elution time with that of standard polystyrene with known molecular weight. Specifically, after preparing a measurement sample with a sample concentration of 1.0 mass% (solvent: chloroform), HLC-8320GPC (manufactured by Tosoh Co., Ltd.) is used as the measurement device and the measurement is performed under the following conditions. Column: 3 K-806L manufactured by Shodex connected in series Eluent: Chloroform Injection volume: 100 μL Flow rate: 1.0 mL/min Column temperature: 40°C Detector: RI (Refractive Index)

(PPE) ・PPE1: dimethylphenol/2-tert-butyl-5-methylphenol copolymer, Mw 25000, OH group number 300 μmol/g Nitrogen was blown into a 40-liter jacketed polymerization tank equipped with a distributor for introducing oxygen-containing gas, a stirring turbine blade and a baffle at the bottom of the polymerization tank and a reflux condenser in the exhaust line at the top of the polymerization tank at a flow rate of 30.9 L/min, while adding 2.4 g of copper oxide, 18.1 g of a 47 mass % aqueous solution of hydrogen bromide, 5.8 g of di-tert-butylethylenediamine, 28.1 g of di-n-butylamine, 85.6 g of butyldimethylamine, 17.9 kg of toluene, 1617 g of 2,6-dimethylphenol, and 383 g of 2-tert-butyl-5-methylphenol to prepare a uniform solution. Next, dry air was introduced from the distributor into the polymerization tank at a rate of 21.0 L/min to initiate polymerization. Dry air was introduced for 105 minutes to obtain a polymerization mixture. Furthermore, the internal temperature was controlled at 40°C during the polymerization process. The polymerization mixture (polymerization liquid) at the end of the polymerization was in a uniform solution state. The introduction of dry air was stopped, and 25.9 g of tetrasodium ethylenediaminetetraacetate (reagent produced by Tongren Chemical Research Institute) was added to the polymerization mixture in the form of 2 kg aqueous solution. The polymerization mixture was stirred at 70°C for 150 minutes, then allowed to stand for 20 minutes, and the organic phase was separated from the aqueous phase by liquid-liquid separation. The above organic phase was concentrated by a rotary evaporator until the polymer concentration became 30% by mass. The above solution was mixed with methanol in a ratio of 4 to the polymer solution to precipitate the polymer. Wet polyphenylene ether was obtained by using a glass filter for reduced pressure filtration. Furthermore, the wet polyphenylene ether was washed with methanol in a ratio of 4 to the wet polyphenylene ether. The above washing operation was performed three times. Thereafter, the wet polyphenylene ether was kept at 140°C and 1 mmHg for 120 minutes to obtain PPE1 in a dry state.

・PPE2: dimethylphenol polymer, Mw 30000, OH group 100 μmol/g The same operation as PPE1 was performed except that the phenol raw material was 2 kg of 2,6-dimethylphenol and the air supply was stopped 117 minutes after the start of air supply.

・PPE3: Product name "SA90", manufactured by Sabic Innovative Plastics, Mw: 4000, OH group number 1100 μmol/g

(Measurement method of molecular weight distribution of PPE) A gel permeation chromatograph (manufactured by Shimadzu Corporation, LC-2030C Plus) was used as the measuring device, and a calibration curve was prepared using standard polystyrene and ethylbenzene. The number average molecular weight (Mn) and weight average molecular weight (Mw) of the obtained modified polyphenylene ether were measured using the calibration curve. As standard polystyrene, molecular weights of 3,650,000, 2,170,000, 1,090,000, 681,000, 204,000, 52,000, 30,200, 13,800, 3,360, 1,300, and 550 were used. The column used was a column made by connecting two K-805L manufactured by Showa Denko Co., Ltd. in series. The solvent used was chloroform, the flow rate of the solvent was set to 1.0 mL/min, and the column temperature was set to 40°C for measurement. A 1 g/L chloroform solution of modified polyphenylene ether was prepared as a sample for measurement. The wavelength of the UV in the detection unit was set to 254 nm in the case of standard polystyrene and 283 nm in the case of polyphenylene ether.

(Measurement method of the number of OH groups of PPE) Weigh 5.0 mg of polyphenylene ether. Then, dissolve the weighed polyphenylene ether in 25 mL of dichloromethane. Add 150 μL of a 2 mass% ethanol solution of tetraethylammonium hydroxide (TEAH) to 2.0 mL of the prepared solution, and then use a UV spectrophotometer (Hitachi, Ltd.: U-3210 model) to measure the absorbance (Abs) at 318 nm (using an absorbance measurement cell with a cell length of 1 cm). Then, based on the measurement results, the number of OH groups obtained from the absorbance is calculated using the following formula (1). Number of OH groups (μmol/g) = [(25×Abs)/(ε×5)]×10 ⁶ …Formula (1) (where ε represents the absorption coefficient, which is 4700 L/mol・cm).

(Method for determining the number of OH groups per molecule of PPE) Using the number average molecular weight obtained by gel permeation chromatography (details as described above), the number of OH groups per molecule of polyphenylene ether is obtained using the following formula (2). Average number of hydroxyl groups per molecule (pieces/molecule) = (number average molecular weight obtained by gel permeation chromatography) × (number of OH groups obtained by absorbance)/10 ⁶ …Formula (2)

(Determination method of molar ratio of dimethylphenol/2-tert-butyl-5-methylphenol copolymer of PPE) The PPE obtained in the examples and comparative examples was dissolved in a measurement solvent (deuterated chloroform in which hydroxyl groups were eliminated by adding 1 drop of deuterated water), and ¹ H-NMR measurement (500 MHz manufactured by JEOL) was performed using tetramethylsilane as an internal standard. During the measurement, polyphenylene ether was kept at 80°C and 1 mmHg for 8 hours to remove volatile components such as toluene or water, and the measurement was performed in the form of unmodified polyphenylene ether in a dry state. The signals of the units derived from dimethylphenol and 2-tert-butyl-5-methylphenol were identified, and the respective ratios were calculated.

(Organic peroxide) ・PBP: Bis(1-tert-butylperoxy-1-methylethyl)benzene (product name "PERBUTYL P", manufactured by NOF Corporation)

<Preparation of resin composition varnish> In order to obtain the 12 kinds of resin compositions in Table 2, each material was weighed in advance, and a toluene/methyl ethyl ketone mixed solvent was placed in a container at a ratio of 50:50. While stirring with a stirrer, each material was added to the mixed solvent, and the mixture was heated to 80°C and mixed for more than 5 hours to prepare a 60% by mass resin composition varnish.

<Preparation of prepreg> Low dielectric constant glass cloth L2116 (weight 94 g/m ² , thickness 91 μm) was impregnated in a resin composition varnish at a fixed tension of about 100 N/m, scraped off with a slit, and dried at 120°C for 10 minutes to prepare a prepreg. After drying, the prepreg was wound on a core tube at a fixed tension of about 200 N/m through 10 rotating rollers. First, a 200 mm × 200 mm piece was cut from the undried prepreg (glass cloth with resin) after slit scraping, and it was confirmed that the slit scraping conditions made the resin adhesion amount 50 wt%.

＜Evaluation Method＞

(1) Prepreg resin powder falling, laminate appearance, and laminate heat resistance The prepreg was rolled out from the core tube and cut into 200 mm × 200 mm. The amount of resin powder falling of the prepreg was calculated based on the amount of resin adhesion of the prepreg after cutting and the amount of resin adhesion of the prepreg before drying. Eight prepregs were stacked, heated at a rate of 3°C/min from room temperature, and vacuum pressed at a pressure of 5 kg/ ^cm2 . After reaching 130°C, they were heated at a rate of 3°C/min, and vacuum pressed at a pressure of 40 kg/ ^cm2 . After reaching 200°C, the temperature was maintained at 200°C and vacuum pressed at a pressure of 40 kg/ ^cm2 for 60 minutes to produce a laminate.

As an evaluation of the appearance of the laminate, the appearance of the laminate was evaluated visually to see if there was blurring. Blurring indicates that the resin was not impregnated into the glass cloth yarn bundle (in Table 2, 0 indicates no blurring, and × indicates blurring). As an evaluation of the heat resistance of the laminate, the laminate was cut into 50 mm × 50 mm pieces, 5 pieces were placed in a pressure cooker at 121°C saturated steam pressure for 10 hours, taken out and the surface moisture was wiped off, and then immersed in a solder bath at 288°C for 20 seconds. The bulging of the laminate was evaluated according to the following evaluation criteria. 0 (good): no bulging at all × (bad): 1 or more bulges

(2) Substrate dielectric loss factor (Df, 10 GHz) Similar to the above heat resistance evaluation, 8 prepregs were stacked to produce a laminate, and the dielectric loss factor at 10 GHz was measured using the cavity resonance method. The measurement was performed using a network analyzer (N5230A, manufactured by Agilent Technologies) and a cavity resonator (Cavity Resornator CP series) manufactured by Kanto Electronics Application Development Co., Ltd. (3) Interlayer insulation reliability For one prepreg, a double-sided copper foil laminate was produced by stacking copper foils with a thickness of 12 μm on top and bottom, cutting it into 50 mm × 50 mm, and etching the upper and lower copper foils to form a pattern on the electrode to produce an evaluation sample. Place 10 evaluation samples in a constant temperature and humidity chamber at 85°C and 85%, apply a voltage of 100 V, and evaluate the interlayer insulation reliability (%) based on the number of short circuits (ratio) after 1000 hours.

The results are shown in Table 2.

[Table 2] Embodiment 1 Embodiment 2 Comparison Example 1 Comparison Example 2 Comparison Example 3 Comparison Example 4 Embodiment 3 Comparison Example 5 Composition Copolymer A 50 50 50 Copolymer B 50 Copolymer C 50 Copolymer D 50 Copolymer E 50 Copolymer F 50 PPE1 50 50 50 50 50 50 PPE2 50 PPE3 50 PBP 1 1 1 1 1 1 1 1 Evaluation Results Prepreg resin powder loss wt% 0.1 0.1 10 0.1 0.1 0.1 0.1 0.1 The laminate has a fuzzy appearance ○ ○ × ○ ○ × ○ × Layer slab bulge ○ ○ ○ × × ○ ○ × Df 10 GHz 0.0026 0.0026 0.0026 0.0026 0.0026 0.0026 0.0026 0.0041 Interlayer insulation reliability% 100 100 10 0 0 0 80 0

As shown in Table 2, in the embodiment, the dielectric properties and interlayer insulation reliability are excellent, and good results are obtained in terms of prepreg resin powder shedding and laminate appearance. In contrast, in the comparative example, sufficient results are not obtained.

The above is an explanation of the implementation method of the present invention, but the present invention is not limited thereto and can be appropriately modified within the scope of the invention. [Industrial Applicability]

The resin composition of the present invention can be well used in the field of resin materials for manufacturing printed wiring boards and prepregs with excellent electrical and mechanical properties.

Claims (6)

A resin composition, characterized in that it comprises the following components: (A) a vinyl aromatic copolymer, (B) a polyphenylene ether, wherein the vinyl aromatic copolymer (A) has structural units derived from a divinyl aromatic compound and structural units derived from a monovinyl aromatic compound, the ratio of the structural units derived from the monovinyl aromatic compound is 55 to 95 mol%, the ratio of the structural units derived from the divinyl aromatic compound is 5 to 45 mol%, and the number average molecular weight is 2000 to 8000, and the polyphenylene ether (B) has an OH group number of 20 to 900 μmol/g and a weight average molecular weight of 10,000 to 50,000. The resin composition of claim 1, wherein the ratio of the component having a molecular weight of 1000 or less as determined by gel permeation chromatography area value in the vinyl aromatic copolymer (A) is 1 to 30%. The resin composition of claim 1, wherein the boron content of the vinyl aromatic copolymer (A) is 0.5 to 5 ppm. The resin composition of claim 1, wherein the polyphenylene ether (B) comprises 5 to 90 mol% of the repeating units derived from the phenol of the following formula (1) and 10 to 95 mol% of the repeating units derived from the phenol of the following formula (2), relative to 100 mol% of the total of the repeating units derived from the phenol of the following formula (1) and the repeating units derived from the phenol of the following formula (2): [Chemical 1] (In formula (1), R ¹¹ is independently a saturated alkyl group having 1 to 6 carbon atoms which may be substituted, an aryl group having 6 to 12 carbon atoms which may be substituted, or a halogen atom, and R ¹² is independently a hydrogen atom, a alkyl group having 1 to 6 carbon atoms which may be substituted, an aryl group having 6 to 12 carbon atoms which may be substituted, or a halogen atom) [Chemical 2] {In formula (2), R ²² is independently a hydrogen atom, a saturated or unsaturated alkyl group having 1 to 20 carbon atoms which may be substituted, an aryl group having 6 to 12 carbon atoms which may be substituted, or a halogen atom, and two R ²² are not hydrogen atoms at the same time, and R ²¹ is a partial structure represented by the following formula (3): [Chemical 3] (In formula (3), R ³¹ is independently a linear alkyl group having 1 to 8 carbon atoms which may be substituted, or a cyclic alkyl group having 1 to 8 carbon atoms to which two R ³¹ are bonded, R ³² is independently an alkylene group having 1 to 8 carbon atoms which may be substituted, b is independently 0 or 1, and R ³³ is a hydrogen atom, an alkyl group having 1 to 8 carbon atoms which may be substituted, or a phenyl group which may be substituted)}. A resin composition varnish comprising the resin composition of any one of claims 1 to 4 and an aromatic solvent. A prepreg comprises the resin composition of any one of claims 1 to 4, a substrate and an aromatic solvent, and contains 0.1 to 1.0 wt % of the aromatic solvent.