Phenol compound

Abstract

To provide a phenol compound useful as a monomer for polyphenylene ether synthesis.SOLUTION: One embodiment of the present invention is a phenol compound that is represented by the following formula (1) and is used for polyphenylene ether synthesis. In the formula (1), R1 and R2 are each independently a C1-C10 alkyl group, n is an integer from 0 to 20, and R3 and R4 are each independently a group including at least one selected from the group consisting of a hydrocarbon group having an unsaturated double bond, a thiol group, and an epoxy group.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to a phenolic compound.

Background Art

[0002] With the spread of high-capacity high-speed communication represented by the fifth-generation communication system (5G) and millimeter-wave radars for automotive ADAS (Advanced Driving Assistance System), the high-frequencyization of signals in communication devices has been progressing.

[0003] However, when an epoxy resin or the like is used as a wiring board material, the relative dielectric constant (Dk) and the dielectric tangent (Df) are not sufficiently low, so that as the frequency increases, the transmission loss due to dielectric loss increases, and problems such as signal attenuation and heat generation occur. Therefore, polyphenylene ether having excellent low dielectric properties has been used.

[0004] In addition, a technique for controlling the performance of the obtained polyphenylene ether by changing the type of monomer used in the polymerization of polyphenylene ether has been developed.

[0005] For example, Patent Document 1 discloses a polyphenylene ether having a reactive group introduced into a side chain using a phenolic compound having an allyl group as a raw material.

Prior Art Documents

Patent Documents

[0006]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0007] As described above, various phenolic compounds have been studied as monomers used in the synthesis of polyphenylene ether, and there is a demand for a phenolic compound capable of synthesizing polyphenylene ether having more excellent performance.

[0008] Therefore, an object of the present invention is to provide a phenol compound that is particularly useful as a monomer for synthesizing polyphenylene ether.

Means for Solving the Problems

[0009] One form of the present invention is a phenol compound represented by the following formula (1).

Chemical formula

[0010] In the formula (1), it is preferable that R1 and R2 are methyl groups. It is preferable that the phenol compound represented by the formula (1) is a phenol compound represented by the following formula (2).

Chemical formula

[0011] It is preferable that the compound represented by the formula (1) is used for the synthesis of polyphenylene ether.

[0012] Another form of the present invention is a composition for synthesizing polyphenylene ether containing the phenol compound.

Effects of the Invention

[0013] According to the present invention, a phenol compound that is particularly useful as a monomer for synthesizing polyphenylene ether is provided.

Brief Description of the Drawings

[0014]

Figure 1

DETAILED DESCRIPTION OF THE INVENTION

[0015] In this specification, when referring to phenols that can be used as raw materials for polyphenylene ether (PPE) and can become constituent units of polyphenylene ether, they may be collectively referred to as "raw material phenols". Also, in this specification, the terms "phenolic compound" and "phenols" may be used interchangeably without distinction.

[0016] In this specification, when describing phenols and using expressions such as "ortho position" or "para position", unless otherwise specified, the position of the phenolic hydroxyl group is taken as the reference (ipso position).

[0017] In this specification, when simply using expressions such as "ortho position", it indicates "at least one of the ortho positions". Therefore, unless there is a particular contradiction, when simply referring to the "ortho position", it may be interpreted as indicating either one of the ortho positions or both ortho positions.

[0018] In this specification, the number average molecular weight (Mn) and weight average molecular weight (Mw) of polyphenylene ether are determined by gel permeation chromatography (GPC). In GPC, Shodex K-805L is used as the column, the column temperature is 40 °C, the flow rate is 1 mL / min, the eluent is chloroform, and the standard substance is polystyrene.

[0019] In this specification, when the upper limit value and lower limit value of a numerical range are separately described, all combinations of each lower limit value and each upper limit value within a non-contradictory range are considered to be substantially described.

[0020] Hereinafter, the phenolic compounds used in the synthesis of polyphenylene ether, the method for synthesizing phenolic compounds, the polyphenylene ether synthesized using phenolic compounds will be described, and then, the curable composition, dry film and prepreg, cured product, and electronic components obtained using polyphenylene ether will be described. The present invention is not limited to the following in any way.

[0021] <<<<Phenolic compound>>>> The phenolic compound of the present disclosure is a phenolic compound having a structure represented by the following formula (1).

[0022] [Chemical formula]

[0023] In formula (1), R1 and R2 are each independently an alkyl group having 1 to 10 carbon atoms. n is an integer from 0 to 20. R3 and R4 are each independently a group containing one or more selected from the group consisting of a hydrocarbon group having an unsaturated double bond, a thiol group, and an epoxy group. It is preferable that R3 and R4 are groups containing a hydrocarbon group having an unsaturated double bond.

[0024] In formula (1), R1 and R2 are each independently preferably an alkyl group having 1 to 8 carbon atoms, an alkyl group having 1 to 5 carbon atoms, an alkyl group having 1 to 4 carbon atoms, an alkyl group having 1 to 3 carbon atoms, or a methyl group. Further, it is more preferable that both R1 and R2 in formula (1) are methyl groups. In the present disclosure, the alkyl group and the alkylene group may be linear or branched.

[0025] In formula (1), n is preferably 1 to 20, 1 to 10, 1 to 5, 1 to 3, or 1.

[0026] The group containing a hydrocarbon group having an unsaturated double bond may be a group containing a hydrocarbon group having an ethylenic unsaturated double bond at the terminal, or a group containing a hydrocarbon group having an ethylenic unsaturated double bond in the skeleton. Examples of the group represented by formula (A) include an alkenyl group and a (meth)acryloyl group. The group containing a hydrocarbon group having an unsaturated double bond is, for example, a group represented by the following formula (A).

[0027]

Chemical formula

[0028] In formula (A), R A1 is a single bond or a hydrocarbon group having 1 to 10 carbon atoms (preferably an alkylene group) which may contain a hetero atom. The number of carbon atoms of R A1 is preferably 1 to 5 or 1 to 3. R A1 is preferably an alkylene group having 1 to 3 carbon atoms. In formula (A), R A2 is hydrogen or a hydrocarbon group having 1 to 10 carbon atoms (preferably an alkyl group) which may contain a hetero atom. The number of carbon atoms of R A2 is preferably 5 or less, 3 or less, or 1. R A2 is preferably hydrogen.

[0029] The group containing a thiol group may be a group containing a thiol group at the terminal or a group containing a thiol group in the skeleton. The group containing a thiol group is, for example, a group represented by the following formula (B).

[0030]

Chemical formula

[0031] In formula (B), R B is a single bond or a hydrocarbon group having 1 to 10 carbon atoms (preferably an alkylene group) which may contain a hetero atom. The number of carbon atoms of R B is preferably 1 to 8.

[0032] The group containing an epoxy group may be a group containing an epoxy group at the terminal, or may be a group containing an epoxy group within the skeleton. The group containing an epoxy group is, for example, a group represented by the following formula (C).

[0033] [Chemical formula]

[0034] In formula (C), R C is a single bond or a hydrocarbon group having 1 to 10 carbon atoms (preferably an alkylene group) which may contain a hetero atom. The number of carbon atoms of R C is preferably 1 to 5 or 1 to 3. R C is preferably an alkylene group having 1 to 3 carbon atoms.

[0035] When the phenol compound represented by formula (1) is used as the raw material phenols of polyphenylene ether, from the viewpoint of excellent dielectric properties of polyphenylene ether and storage stability of the polyphenylene ether composition, it is preferably a group containing a hydrocarbon group having an unsaturated double bond, more preferably a vinyl group or an allyl group, and particularly preferably an allyl group.

[0036] The phenols represented by formula (1) are particularly preferably the phenols represented by the following formula (2).

[0037] [Chemical formula]

[0038] When the phenolic compound represented by the formula (1) is used as a monomer for synthesizing polyphenylene ether, the structure derived from the formula (1) is incorporated into the terminal portion of the synthesized polyphenylene ether. Thereby, it is easy to obtain a polyphenylene ether having an appropriate reactivity derived from the reactive groups (hydrocarbon group having an unsaturated double bond, thiol group, or epoxy group) contained in R3 and R4 bonded to the isocyanurate ring. Further, since the phenolic compound represented by the formula (1) does not have hydrogen atoms at the highly reactive ortho and para positions, the polymerization reaction easily stops at the terminal of the polyphenylene ether molecular chain in which the phenolic compound represented by the formula (1) has reacted. Therefore, when the phenolic compound represented by the formula (1) appropriately constitutes the terminal portion of the polyphenylene ether, the rapid increase in molecular weight (coupling reaction) that occurs in the synthesis of the polyphenylene ether having a branched structure described later can be suppressed, and thus it becomes easy to control the molecular weight of the polyphenylene ether. Therefore, the polyphenylene ether obtained by using the phenolic compound represented by the formula (1) easily provides a cured film having excellent mechanical properties while maintaining low dielectric characteristics. Further, since an unintended increase in molecular weight is suppressed when synthesizing the polyphenylene ether, it is likely to have excellent storage stability.

[0039] Thus, the phenolic compound represented by the formula (1) is particularly useful as a monomer used for synthesizing polyphenylene ether. In other words, the phenolic compound represented by the formula (1) is preferably used as the starting phenols contained in the composition for synthesizing polyphenylene ether.

[0040] Note that the phenolic compound represented by the formula (1) may be used other than for the synthesis of polyphenylene ether. For example, the phenolic compound represented by the formula (1) can also be used as a crosslinking agent or a curing agent.

[0041] <<<<Synthesis Example of Phenolic Compound>>>> The phenolic compound represented by formula (1) is obtained by reacting a phenolic compound having a predetermined functional group (substituents represented by R1 and R2 in formula (1)) with a compound containing an isocyanurate ring structure having a predetermined functional group (substituents represented by R3 and R4 in formula (1)) by a well-known and commonly used method.

[0042] Various conditions (such as the catalyst and solvent used, reaction temperature, reaction time, etc.) in the synthesis of the phenolic compound represented by formula (1) can be appropriately adjusted according to the raw materials used and the like.

[0043] For example, the compound where n = 1 in formula (1) is obtained by reacting the compound represented by the following formula (1a) with the compound represented by the following formula (1b) in the presence of hexamethylenetetramine, paraformaldehyde, etc.

[0044]

Chemical formula

[0045] In formula (1a), R1 and R2 are respectively the same as R1 and R2 in formula (1).

[0046]

Chemical formula

[0047] In formula (1b), R3 and R4 are respectively the same as R3 and R4 in formula (1).

[0048] In addition, the compound represented by formula (1) in which R3 and R4 are groups containing a thiol group or an epoxy group can also be obtained by modifying the unsaturated double bond of the compound represented by formula (1) in which R3 and R4 are groups containing a hydrocarbon group having an unsaturated double bond into a thiol group or an epoxy group. Examples of the method for modifying an unsaturated double bond into a thiol group include a thiol-ene reaction using a dithiol compound as described in ACS Nano 2016, 10, 1, 930-937. Examples of the method for modifying an unsaturated double bond into an epoxy group include an oxidation reaction of an unsaturated double bond using a peracid as described in Patent No. 5673963.

[0049] In addition, the phenol compound represented by formula (2) can be obtained by reacting 2,6-dimethylphenol in which R1 and R2 in formula (1b) are methyl groups with diallyl isocyanurate in which R3 and R4 in formula (1b) are allyl groups. Details of the synthesis method of the phenol compound represented by formula (2) will be described later.

[0050] The phenol compound represented by formula (1) (for example, the phenol compound obtained using the compound represented by formula (1a) and the compound represented by formula (1b)) can be easily synthesized by one-pot synthesis and can also be easily purified by reprecipitation or the like.

[0051] <<<<Polyphenylene ether>>>> The polyphenylene ether of the present disclosure is synthesized using raw material phenols containing at least the phenol compound represented by formula (1).

[0052] The raw material phenols of the polyphenylene ether may contain conventionally known phenol compounds other than the phenol compound represented by formula (1). Examples of the conventionally known phenol compounds other than the phenol compound represented by formula (1) include phenols satisfying the following condition (1) and other phenols.

[0053] In the synthesis of polyphenylene ether, the content of the phenolic compound represented by the formula (1) relative to the total amount of raw material phenols is preferably 0.1 mol% or more, 0.2 mol% or more, 0.5 mol% or more, or 1.0 mol% or more, and is preferably 50 mol% or less, 40 mol% or less, 30 mol% or less, 20 mol% or less, 15 mol% or less, or 10 mol% or less.

[0054] As described above, when the phenolic compound represented by the formula (1) is used as the raw material phenols for polyphenylene ether, the resulting polyphenylene ether will have appropriate reactivity derived from the formula (1) and the control of the molecular weight will be facilitated. Further, the cured film obtained using such polyphenylene ether is likely to have excellent mechanical properties.

[0055] Here, International Publication No. 2020 / 017570 etc. disclose polyphenylene ethers having a branched structure. Such polyphenylene ethers having a branched structure are useful polyphenylene ethers such as having high solvent solubility. However, it has been found that polyphenylene ethers having a branched structure have more polymer terminals having polymerization reactivity than polyphenylene ethers having a linear structure, and thus there is a tendency for the grown polymers to further polymerize (couple) and the molecular weight to increase rapidly. Therefore, in order to control the molecular weight of the resulting polyphenylene ether within a desired range, selection of raw materials, fine adjustment of synthesis conditions, etc. are required, and it may not be suitable for mass production. However, when the phenolic compound represented by the formula (1) is used as the raw material for polyphenylene ether having a branched structure, as described above, it becomes possible to easily control the molecular weight and the performance of the resulting cured film can be improved. Therefore, the phenolic compound represented by the formula (1) can be particularly preferably used in the synthesis of polyphenylene ether having a branched structure.

[0056] The polyphenylene ether having a branched structure using the phenolic compound represented by the following formula (1) as the raw material phenols will be described below.

[0057] <<<Polyphenylene ether having a branched structure>>> <<Raw material>> The raw material phenols of the polyphenylene ether having a branched structure include the phenolic compound represented by the above formula (1) and phenols satisfying at least the following condition 1. (Condition 1) Having hydrogen atoms at the ortho and para positions

[0058] In addition, the raw material phenols may contain other phenols.

[0059] The following describes each of the phenols. However, the phenolic compound represented by the formula (1) is as described above.

[0060] The raw material phenols shown below mainly disclose monohydric phenols. However, polyhydric phenols may be used as the raw material phenols as long as the effects of the present disclosure are not inhibited.

[0061] <Phenols satisfying at least condition 1> Phenols satisfying at least condition 1 have hydrogen atoms at the ortho and para positions.

[0062] In addition, the phenols satisfying at least condition 1 may further satisfy the following condition 2. (Condition 2) Having a hydrogen atom at the para position and having a functional group containing an unsaturated carbon bond

[0063] That is, the phenols satisfying at least condition 1 may be either (1) phenols satisfying only condition 1 and not satisfying condition 2 or (2) phenols satisfying both condition 1 and condition 2. In addition, the raw material phenols may contain both of these phenols.

[0064] Since phenols that satisfy Condition 1 have a hydrogen atom at the ortho position, when they are oxidatively polymerized with other phenols, ether bonds can be formed not only at the ipso and para positions but also at the ortho position. Therefore, polyphenylene ether obtained using such phenols as raw material phenols can form a branched-chain structure. Note that when phenols that satisfy Condition 1 are not used, polyphenylene ether forms a linear structure. More specifically, polyphenylene ether obtained from raw material phenols containing phenols that satisfy Condition 1 has a structure in which a part of the structure is branched by a benzene ring ether-bonded at at least three positions: the ipso position, the ortho position, and the para position. Thus, according to polyphenylene ether having a branched structure in the skeleton, excellent solubility in organic solvents can be obtained.

[0065] In addition, since phenols that satisfy Condition 2 have a functional group containing an unsaturated carbon bond, polyphenylene ether obtained using such phenols as raw material phenols has a functional group containing an ethylenic or acetylenic carbon-carbon multiple bond. More specifically, polyphenylene ether obtained from raw material phenols containing phenols that satisfy Condition 2 has a structure in which a part of the structure has a functional group containing an unsaturated carbon bond at at least one of the meta position of the benzene ring or two ortho positions.

[0066] Examples of phenols that satisfy only Condition 1 and do not satisfy Condition 2 include phenol, o-cresol, m-cresol, o-ethylphenol, m-ethylphenol, 2,3-xylenol, 2,5-xylenol, 3,5-xylenol, o-tert-butylphenol, m-tert-butylphenol, o-phenylphenol, m-phenylphenol, 2-dodecylphenol, and the like. As phenols that satisfy Condition 1, only one kind may be used, or two or more kinds may be used.

[0067] Examples of phenols that satisfy both Condition 1 and Condition 2 include o-vinylphenol, m-vinylphenol, o-allylphenol, m-allylphenol, 3-vinyl-6-methylphenol, 3-vinyl-6-ethylphenol, 3-vinyl-5-methylphenol, 3-vinyl-5-ethylphenol, 3-allyl-6-methylphenol, 3-allyl-6-ethylphenol, 3-allyl-5-methylphenol, 3-allyl-5-ethylphenol, and the like. As the phenols that satisfy Condition 1 and Condition 2, only one kind may be used, or two or more kinds may be used.

[0068] In the synthesis of polyphenylene ether, the content of phenols that satisfy at least Condition 1 with respect to the total amount of raw material phenols is preferably 1 mol% or more, 2 mol% or more, 3 mol% or more, or 5 mol% or more, and is preferably 50 mol% or less, 40 mol% or less, 30 mol% or less, 20 mol% or less, or 15 mol% or less.

[0069] <Other phenols> Other phenols do not satisfy Condition 1 and do not correspond to the phenol compound represented by the formula (1).

[0070] Examples of those that satisfy Condition 2 among other phenols include 2-allyl-6-methylphenol, 2-allyl-6-ethylphenol, 2-allyl-6-phenylphenol, 2-allyl-6-styrylphenol, 2,6-divinylphenol, 2,6-diallylphenol, 2,6-diisopropenylphenol, 2,6-dibutenylphenol, 2,6-diisobutenylphenol, 2,6-diisopentenylphenol, 2-methyl-6-styrylphenol, 2-vinyl-6-methylphenol, 2-vinyl-6-ethylphenol, and the like. In addition, examples of phenols that do not satisfy condition 2 among other phenols include 2,6-dimethylphenol, 2,3,6-trimethylphenol, 2-methyl-6-ethylphenol, 2-ethyl-6-n-propylphenol, 2-methyl-6-n-butylphenol, 2-methyl-6-phenylphenol, 2,6-diphenylphenol, 2,6-ditolylphenol, and the like.

[0071] In addition, as other phenols, phenols having no hydrogen atom at either the para position or the ortho position may be used.

[0072] As for other phenols, only one kind may be used, or two or more kinds may be used.

[0073] In the synthesis of polyphenylene ether, when other phenols are used, the content rate of other phenols with respect to the total amount of raw material phenols is, for example, 10 mol% or more, 20 mol% or more, 30 mol% or more, 40 mol% or more, 50 mol% or more.

[0074] <<<Molecular weight>>> The weight average molecular weight of the polyphenylene ether according to the present disclosure is preferably 5,000 to 200,000, more preferably 10,000 to 100,000. The number average molecular weight of the polyphenylene ether is preferably 4,000 to 20,000, more preferably 5,000 to 10,000.

[0075] The molecular weight of the polyphenylene ether according to the present disclosure depends on the types of raw material phenols used, but it can be adjusted by changing the reaction temperature, reaction time, etc. during synthesis. In addition, by increasing the ratio of the phenol compound represented by formula (1) in the raw material phenols and the ratio of phenols having no hydrogen atom at the para position and the ortho position in other phenols, the polymerization reaction is suppressed, the rate of increase in molecular weight is suppressed, and the molecular weight control of the polyphenylene ether becomes easy.

[0076] <<<Manufacturing Method>>> The polyphenylene ether according to the present disclosure can be produced by a known polyphenylene ether synthesis method, except that the raw material phenols and the ratio of the raw material phenols used are as described above. For example, the polyphenylene ether having a branched structure can be produced with reference to the synthesis method disclosed in International Publication No. 2020 / 017570, and the polyphenylene ether having a linear structure can also be produced in the same manner except that phenols satisfying Condition 1 are not used.

[0077] The polyphenylene ether is usually polymerized using a composition for synthesizing polyphenylene ether (polymerization solution) containing raw material phenols. The composition for synthesizing polyphenylene ether may contain a catalyst, a solvent, etc. as disclosed in International Publication No. 2020 / 017570 in addition to the raw material phenols (such as the phenol compound represented by Formula (1)) described above.

[0078] Examples of the catalyst include amine compounds, and metal amine compounds composed of heavy metal compounds such as copper, manganese, and cobalt and amine compounds such as tetramethylethylenediamine. In particular, in order to obtain a copolymer having a sufficient molecular weight, it is preferable to use a copper-amine compound in which a copper compound is coordinated with an amine compound. Only one type of catalyst may be used, or two or more types may be used.

[0079] The content of the catalyst is not particularly limited, but it may be, for example, 0.1 to 0.6 mol% with respect to the total of the raw material phenols in the composition for synthesizing polyphenylene ether.

[0080] Specific examples of the solvent include aromatic hydrocarbons such as benzene, toluene, xylene, and ethylbenzene; halogenated aromatic hydrocarbons such as chloroform, methylene chloride, chlorobenzene, dichlorobenzene, and trichlorobenzene; nitro compounds such as nitrobenzene; methyl ethyl ketone (MEK), cyclohexanone, tetrahydrofuran, ethyl acetate, N-methyl-2-pyrrolidone (NMP), N,N-dimethylformamide (DMF), propylene glycol monomethyl ether acetate (PMA), diethylene glycol monoethyl ether acetate (CA), and the like. Only one kind of solvent may be used, or two or more kinds may be used. Note that the solvent may contain water, a solvent miscible with water, or the like. The content of the solvent in the composition for synthesizing polyphenylene ether is not particularly limited and may be adjusted as appropriate.

[0081] <<<<Curable Composition>>>> The curable composition of the present disclosure contains polyphenylene ether synthesized using raw material phenols containing at least a phenol compound represented by formula (1). The curable composition may also contain other components.

[0082] The content of polyphenylene ether in the curable composition is preferably 40 to 90% by mass, more preferably 50 to 80% by mass, based on the total amount excluding volatile components and inorganic fillers in the curable composition.

[0083] Examples of other components include inorganic fillers such as silica, peroxides, crosslinking-type curing agents, polyphenylene ethers other than the polyphenylene ether according to the present embodiment, polymerization initiators, maleimide resins, resin and polymer components such as styrene-based elastomers, sensitizers, adhesion aids, surfactants, leveling agents, plasticizers, adhesives, colorants, fibers, silane coupling agents, flame retardants, cellulose nanofibers, dispersants, thermosetting catalysts, thickeners, defoamers, antioxidants, rust inhibitors, adhesion-imparting agents, and other additives.

[0084] Other components may be appropriately selected according to the use and the like. As an example, when the curable composition contains a peroxide, the crosslinking reaction of the curable composition is promoted, and various physical properties of the cured product are likely to be improved. Further, when the curable composition contains a crosslinking type curing agent, various physical properties of the cured product are likely to be improved.

[0085] Examples of the peroxide include methyl ethyl ketone peroxide, methyl acetoacetate peroxide, acetylacetone peroxide, 1,1-bis(t-butylperoxy)cyclohexane, 2,2-bis(t-butylperoxy)butane, t-butyl hydroperoxide, cumene hydroperoxide, diisopropylbenzene hydroperoxide, 2,5-dimethylhexane-2,5-dihydroperoxide, 1,1,3,3-tetramethylbutyl hydroperoxide, di-t-butyl hydroperoxide, t-butyl hydroperoxide, dicumyl peroxide, 2,5-dimethyl-2,5-di(t-butylperoxy)hexane, 2,5-dimethyl-2,5-di(t-butylperoxy)hexyne, 2,5-dimethyl-2,5-di(t-butylperoxy)-3-butene, acetyl peroxide, octanoyl peroxide, lauroyl peroxide, benzoyl peroxide, m-toluoyl peroxide, diisopropyl peroxydicarbonate, t-butylene peroxybenzoate, di-t-butyl peroxide, t-butyl peroxyisopropyl monocarbonate, α,α'-bis(t-butylperoxy-m-isopropyl)benzene, and the like. The peroxide may be used alone or in combination of two or more.

[0086] When the content of the polyphenylene ether in the curable composition is 100 parts by mass, the content of the peroxide in the curable composition is preferably 0.1 to 10 parts by mass, and more preferably 1 to 8 parts by mass.

[0087] Examples of the crosslinking hardeners include polyfunctional vinyl compounds such as divinylbenzene, divinylnaphthalene, and divinylbiphenyl; vinylbenzyl ether compounds synthesized from the reaction of phenol and vinylbenzyl chloride; styrene monomers such as diallyl phthalate and diallyl isophthalate, allyl ether compounds synthesized from the reaction of phenol and allyl chloride; and trialkenyl isocyanurates such as triallyl isocyanurate (hereinafter, TAIC (registered trademark)) and triallyl cyanurate. Among them, triallyl isocyanurate, triallyl cyanurate, diallyl phthalate, and diallyl isophthalate, which have particularly good compatibility with polyphenylene ether, are preferred. The crosslinking hardener may be used alone or in combination of two or more.

[0088] When the content of the polyphenylene ether in the curable composition is 100 parts by mass, the content of the crosslinking hardener in the curable composition is preferably 1 to 100 parts by mass, and more preferably 10 to 80 parts by mass.

[0089] Also, the curable composition may be in the form of a varnish containing a solvent. As the solvent, a solvent capable of dissolving the above-mentioned polyphenylene ether is preferred. For example, in addition to conventionally usable solvents such as chloroform, methylene chloride, and toluene, N-methyl-2-pyrrolidone (NMP), tetrahydrofuran (THF), cyclohexanone, propylene glycol monomethyl ether acetate (PMA), diethylene glycol monoethyl ether acetate (CA), methyl ethyl ketone, ethyl acetate, etc. are preferably used. These may be used alone or in combination of two or more.

[0090] <<<<Dry film, prepreg>>>> The dry film has a resin layer made of the curable composition of the present disclosure on a carrier film (support film). The dry film is used by laminating the resin layer so as to be in contact with the substrate.

[0091] The dry film can be manufactured by uniformly applying a curable composition onto a carrier film by an appropriate method such as a blade coater, a lip coater, a comma coater, a film coater, etc., drying it to form the resin layer described above, and preferably laminating a cover film (protective film) thereon. The cover film and the carrier film may be made of the same film material or different films.

[0092] As the film materials for the carrier film and the cover film, any known materials used for dry films can be used.

[0093] As the carrier film, for example, a thermoplastic film such as a polyester film such as polyethylene terephthalate with a thickness of 2 to 150 μm is used.

[0094] As the cover film, a polyethylene film, a polypropylene film, etc. can be used, but it is preferable that the adhesive force with the resin layer is smaller than that of the carrier film.

[0095] The film thickness of the resin layer on the dry film is preferably 100 μm or less, and more preferably in the range of 5 to 50 μm.

[0096] The prepreg can be obtained, for example, by impregnating a base material such as a glass cloth with a curable composition and drying it.

[0097] <<<<Cured product>>>> A cured product can be manufactured using a curable composition or a dry film having a resin layer made of the curable composition.

[0098] The method for obtaining a cured product from the curable composition is not particularly limited and can be appropriately changed according to the composition of the curable composition.

[0099] For example, a cured product can be formed by the following methods. After applying the curable composition on the substrate as described above (for example, applying with an applicator or the like), a drying step of drying the curable composition as necessary is carried out to form a resin layer on the substrate. Alternatively, a dry film is laminated on the substrate to transfer a resin layer made of the curable composition. Next, a thermosetting step of thermally crosslinking the polyphenylene ether by heating (for example, heating with an inert gas oven, a hot plate, a vacuum oven, a vacuum press machine, etc.) is carried out to cure the resin layer.

[0100] The implementation conditions in each step (for example, coating thickness, drying temperature and time, heating temperature and time, etc.) may be appropriately changed according to the composition and use of the curable composition.

[0101] <<<<Electronic component>>>> The electronic component has the cured product of the present disclosure described above. Since the cured product of the present disclosure has excellent dielectric properties, mechanical strength, etc., it can be used in various applications as a material for constituting a laminate or an electronic component.

[0102] Its use is not particularly limited, but preferably, it includes insulating materials in electronic components such as high-capacity high-speed communication represented by the fifth-generation communication system (5G) and millimeter-wave radars for automotive ADAS (advanced driving assistance system).

Example

[0103] <<Synthesis of phenolic compound>> Into a 100 mL two-necked flask, diallyl isocyanurate (19.14 g, 91.49 mmol), 2,6-dimethylphenol (13.43 g, 109.9 mmol), hexamethylenetetramine (0.125 g, 0.892 mmol), paraformaldehyde (4.396 g), DMF (45.39 g), and ion-exchanged water (1.22 g) were added. Nitrogen bubbling was carried out for 15 minutes to make the reaction system under a nitrogen atmosphere, and the mixture was heated and stirred at 120 °C for 18 hours. The reaction solution was dropped into a reprecipitation solvent (methanol:ion-exchanged water:35% hydrochloric acid = 150:600:1.5 mL), and the phenolic compound (4DT-26DMP) represented by formula (2) (28.9 g, 84.2 mmol) was obtained as a white powder with a yield of 92%. Figure 1 shows the 1 1H-NMR spectrum (400 MHz, CDCl3, room temperature) of 4DT-26DMP.

[0104]

Chemical formula

[0105] <<Synthesis of polyphenylene ether>> <Example 1> As raw material phenols, 2,6-dimethylphenol, 2-allylphenol, and 4DT-26DMP were used. 2,6-dimethylphenol (8.33 g), 2-allylphenol (1.03 g), 4DT-26DMP (0.71 g), and toluene (56.7 g) were added to a 100 mL two-necked eggplant flask and stirred to completely dissolve the raw material phenols, obtaining a composition. The ratio of the raw material phenols was 2,6-dimethylphenol: 87.6 mol%, 2-allylphenol: 10 mol%, and 4DT-26DMP: 2.4 mol%. TMEDA (0.207 g) and a Cu / TMEDA catalyst (0.227 g) were added to the composition and stirred (magnetic stirrer, 350 rpm). Dry air was bubbled at 30 mL / min, and the composition was heated and stirred at 40 °C for 15 hours as the reaction time to obtain a reaction solution. The obtained reaction solution was filtered through a 5C filter paper, and the filtrate was dropped into a reprecipitation solvent of alcohol K (0.3 L), ion-exchanged water (5 mL), and 35% hydrochloric acid (1 mL), and the precipitate was filtered to obtain polyphenylene ether (PPE-DT-1) (9.51 g) according to Example 1 as a light brown powder. PPE-DT-1 has a number average molecular weight of 7,000 and a weight average molecular weight of 81,300.

[0106] <Example 2> A polyphenylene ether (PPE-DT-2) according to Example 2 was obtained in the same manner as in Example 1, except that the ratio of the raw material phenols was changed to 2,6-dimethylphenol: 85 mol%, 2-allylphenol: 10 mol%, and 4DT-26DMP: 5 mol%. PPE-DT-2 has a number average molecular weight of 8,900 and a weight average molecular weight of 70,300.

[0107] <Example 3> A polyphenylene ether (PPE-DT-3) according to Example 3 was obtained in the same manner as in Example 1, except that the ratio of the raw material phenols was changed to 2,6-dimethylphenol: 81 mol%, 2-allylphenol: 10 mol%, and 4DT-26DMP: 9 mol%. PPE-DT-3 has a number average molecular weight of 7,300 and a weight average molecular weight of 21,300.

[0108] <Comparative Example 1> A polyphenylene ether (PPE-TM) according to Comparative Example 1 was obtained in the same manner as in Example 1, except that 2,6-dimethylphenol: 75 mol%, 2-allylphenol: 10 mol%, and 2,4,6-trimethylphenol: 15 mol% were used as the raw material phenols. PPE-TM has a number average molecular weight of 6,000 and a weight average molecular weight of 16,200.

[0109] <Reference Example 1> A polyphenylene ether (PPE-1) according to Reference Example 1 was obtained in the same manner as in Example 1, except that 4DT-26DMP was not used and the ratio of the raw material phenols was 2,6-dimethylphenol: 90 mol% and 2-allylphenol: 10 mol%.

[0110] <<<Evaluation>>> <<Change in Molecular Weight of PPE>> Table 1 shows the change in the weight average molecular weight (Mw) of each polyphenylene ether of Examples 1 to 3 and Reference Example 1 for each reaction time. Table 2 shows the change in the PDI of each polyphenylene ether of Examples 1 to 3 and Reference Example 1 for each reaction time.

[0111]

Table 1

[0112]

Table 2

[0113] As shown in Table 1 and Table 2, it was confirmed that for PPE-DT-1 to PPE-DT-3 using 4DT-26DMP as the raw material phenols, the increase in molecular weight and PDI was gentle compared to PPE-1. On the other hand, for PPE-1, when the reaction time became longer, a sharp increase in molecular weight and PDI occurred, and gelation occurred when the reaction time was 15 hours. Also, since the sharp increase in molecular weight of PPE-DT-1 to PPE-DT-3 is suppressed, it is understood that it is easy to produce polyphenylene ether in the desired molecular weight range and is more likely to have excellent storage stability.

[0114] <<Cured film>> <Preparation of curable composition> According to the following procedure, cured films using PPE-DT-1 to PPE-DT-3 and PPE-TM were produced in the amounts shown in Table 3, and the film physical properties were evaluated.

[0115] <Production of cured film> 100 parts by mass of each polyphenylene ether, 50 parts by mass of a crosslinking type curing agent (product name "TAIC", manufactured by Shinryo Corporation), and 5 parts by mass of a peroxide (product name "Perbutyl P40", manufactured by NOF Corporation) were mixed with 350 parts by mass of cyclohexanone (solvent) to prepare a curable composition. Each curable composition was applied to the shiny surface of a 18 μm thick copper foil so that the film thickness after drying was the thickness shown in Table 3, and dried in a hot air circulation drying oven at 90 °C for 30 minutes. Then, after curing in an inert oven at 200 °C for 1 h, the copper foil was etched to obtain a self-supporting single cured film (measurement sample).

[0116] <Crack> The occurrence of cracks in each cured film was confirmed. In Examples 1 - 3, no cracks occurred in the cured products. In Comparative Example 1, a large number of cracks occurred in the cured product and a self-supporting single cured film could not be obtained. Therefore, the following film physical property evaluation could not be performed for Comparative Example 1.

[0117] <Dielectric constant> A sample for measurement, cut to a length of 80 mm and a width of 45 mm, was used as a test piece, and the relative dielectric constant Dk and the dielectric loss tangent Df were measured by the SPDR (Split Post Dielectric Resonator) resonator method. As the measuring instrument, a vector network analyzer E5071C manufactured by Keysight Technologies Co., Ltd., an SPDR resonator, and a calculation program manufactured by QWED were used. The conditions were a frequency of 10 GHz and a measurement temperature of 25°C. The evaluation results are shown in Table 3.

[0118] <Tensile properties> A measurement sample was cut out to a length of 8 cm and a width of 0.5 cm, and the tensile strength and elongation (elongation at break) were measured under the following conditions. The elastic modulus was determined from the slope of the strain in the obtained stress-strain diagram when the stress was from 5 MPa to 10 MPa. [Measurement conditions] Testing machine: Tensile testing machine EZ-SX (manufactured by Shimadzu Corporation) Distance between chucks: 50 mm Testing speed: 1 mm / min Elongation calculation: (Tensile movement amount / Distance between chucks) × 100

[0119]

Table 3

[0120] As shown in Table 3, the cured films obtained using PPE-DT-1 to PPE-DT-3 have excellent mechanical properties due to having reactive groups at the ends, and it was also confirmed that they are excellent in dielectric constant.

Industrial applicability

[0121] The phenolic compound according to the present invention has effects such as suppressing a rapid increase in molecular weight during the synthesis of polyphenylene ether, and thus is particularly useful as a monomer for polyphenylene ether synthesis (or raw material phenols contained in a composition for polyphenylene ether synthesis).

Claims

1. A phenolic compound represented by the following formula (1). 【Chemical Formula 1】 In formula (1), R １ , R ２ are each independently an alkyl group having 1 to 10 carbon atoms, n is an integer from 0 to 20, R ３ and R ４ each independently represents a group containing one or more selected from the group consisting of a hydrocarbon group having an unsaturated double bond, a thiol group, and an epoxy group.

2. In the formula (1), R １ and R ２ are methyl groups, and the phenolic compound according to claim 1.

3. The phenolic compound according to Claim 1, which is a phenolic compound represented by the following formula (2). 【Chemical 2】

4. The phenolic compound according to Claim 1, which is used in the synthesis of polyphenylene ether.

5. A composition for polyphenylene ether synthesis, comprising the phenolic compound according to any one of Claims 1 to 3.

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