Polyphenylene ether, curable composition, dry film, prepreg, cured product, laminate, and electronic component

Abstract

To provide a phenol compound useful as a monomer for polyphenylene ether synthesis.SOLUTION: One embodiment of the present invention is a polyphenylene ether derived from a starting phenol material, wherein the starting phenol material includes a phenol represented by a formula (1). In the formula, 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 containing an unsaturated double bond, a thiol group, and an epoxy group.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to polyphenylene ether, curable composition, dry film, prepreg, cured product, laminate, and electronic component.

Background Art

[0002] With the spread of high-capacity high-speed communication typified 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 in which a reactive group is introduced into the 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] Conventionally, various phenol compounds have been studied as monomers used in the synthesis of polyphenylene ether, and polyphenylene ether having excellent performance has been demanded. Further, in the production of polyphenylene ether, the molecular weight may rapidly increase during the polymerization reaction, and it has been difficult to control the molecular weight, such as the need to strictly control the reaction conditions in order to bring the molecular weight of polyphenylene ether within a desired range.

[0008] Therefore, an object of the present invention is to provide a polyphenylene ether that is easy to control the molecular weight and is capable of stably producing a cured film having excellent performance.

Means for Solving the Problems

[0009] One embodiment of the present invention is a polyphenylene ether obtained from raw material phenols, wherein the raw material phenols include phenols represented by the following formula (1).

Chemical formula

[0010] The phenols represented by the formula (1) are preferably phenols represented by the following formula (2).

Chemical formula

[0011] The raw material phenols preferably contain, in addition to the phenols represented by the formula (1), phenols satisfying at least the following condition 1. (Condition 1) Having hydrogen atoms at the ortho and para positions

[0012] Another form of the present invention is a curable composition containing the polyphenylene ether.

[0013] Yet another form of the present invention is a dry film or prepreg obtained by applying or impregnating the curable composition to a substrate.

[0014] Still another form of the present invention is a cured product obtained by curing the curable composition.

[0015] Still another form of the present invention is a laminate containing the cured product.

[0016] Still another form of the present invention is an electronic component having the cured product.

Advantages of the Invention

[0017] According to the present invention, there is provided a polyphenylene ether in which the molecular weight can be easily controlled and a cured film having excellent performance can be stably produced.

Brief Description of the Drawings

[0018]

Figure 1

Embodiments for Carrying Out the Invention

[0019] In this specification, when referring to phenols used as raw materials for polyphenylene ether (PPE) and collectively referring to phenols that can become constituent units of polyphenylene ether, they may be referred to as "raw material phenols". Also, in this specification, "phenolic compounds" and "phenols" may be used without distinction.

[0020] In this specification, when explaining phenols and expressing "ortho position" or "para position", etc., unless otherwise specified, the position of the phenolic hydroxyl group is used as the reference (ipso position).

[0021] In this specification, when simply expressed as "ortho position" or the like, it means "at least one of the ortho positions". Therefore, as long as there is no particular contradiction, when simply referred to as the "ortho position", it may be interpreted as indicating either one of the ortho positions, or it may be interpreted as indicating both of the ortho positions.

[0022] In this specification, the number average molecular weight (Mn) and weight average molecular weight (Mw) of the 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.

[0023] In this specification, when the upper limit value and the 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 substantially described.

[0024] Hereinafter, polyphenylene ether, a curable composition containing polyphenylene ether, a dry film and a prepreg, a cured product, and an electronic component will be described. The present invention is not limited to the following.

[0025] <<<<Polyphenylene ether>>>> <<<Raw material phenols>>> The polyphenylene ether of the present disclosure is synthesized using raw material phenols containing at least a phenol compound represented by the following formula (1). Further, the polyphenylene ether of the present disclosure may contain a phenol compound (other phenols) other than the specific phenol compound as the raw material phenols. Hereinafter, each phenol compound (phenols) will be described.

[0026] <<Phenol compound represented by formula (1)>> The polyphenylene ether of the present disclosure contains a phenol compound represented by the following formula (1) as the raw material phenols.

[0027] [Chemical formula]

[0028] 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.

[0029] 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. Moreover, 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.

[0030] In formula (1), n is preferably 1 to 20, 1 to 10, 1 to 5, 1 to 3, or 1.

[0031] 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 may be 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).

[0032] [Chemical formula]

[0033] In formula (A), R A1is a single bond or a hydrocarbon group having 1 to 10 carbon atoms which may contain a hetero atom (preferably an alkylene group). R A1 preferably has 1 to 5 or 1 to 3 carbon atoms. 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 which may contain a hetero atom (preferably an alkyl group). R A2 preferably has 5 or less, 3 or less, or 1 carbon atom. R A2 is preferably hydrogen.

[0034] 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).

[0035]

Chemical formula

[0036] In formula (B), R B is a single bond or a hydrocarbon group having 1 to 10 carbon atoms which may contain a hetero atom (preferably an alkylene group). R B preferably has 1 to 8 carbon atoms.

[0037] The group containing an epoxy group may be a group containing an epoxy group at the terminal or a group containing an epoxy group in the skeleton. The group containing an epoxy group is, for example, a group represented by the following formula (C).

[0038]

Chemical formula

[0039] In formula (C), R C is a single bond or a hydrocarbon group having 1 to 10 carbon atoms which may contain a hetero atom (preferably an alkylene group). R CThe carbon number is preferably 1 to 5 or 1 to 3. R C is preferably an alkylene group having 1 to 3 carbon atoms.

[0040] When the phenol compound of the present disclosure is used as a raw material phenol for 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.

[0041] The phenols represented by formula (1) are particularly preferably the phenols represented by the following formula (2).

[0042]

Chemical formula

[0043] When the phenolic compound represented by the formula (1) is used as a monomer for synthesizing polyphenylene ether, a structure derived from the formula (1) is incorporated into the terminal portion of the synthesized polyphenylene ether. As a result, it is easy to obtain a polyphenylene ether having appropriate reactivity derived from the reactive groups (hydrocarbon groups having an unsaturated double bond, thiol groups, or epoxy groups) 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, a rapid increase in molecular weight (coupling reaction) occurring in the synthesis of the polyphenylene ether having a branched structure described later can be suppressed, so that it is 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 gives a cured film having excellent mechanical properties while maintaining low dielectric properties. Further, when synthesizing polyphenylene ether, since an unintended increase in molecular weight is suppressed, it is likely to have excellent storage stability.

[0044] In the synthesis of polyphenylene ether, the content of the phenolic compound represented by the formula (1) with respect 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.

[0045] <Synthesis example of the phenolic compound represented by the formula (1)> The phenolic compound represented by the formula (1) can be obtained by reacting a phenolic compound having a predetermined functional group (substituents represented by R1 and R2 in the formula (1)) with a compound containing an isocyanurate ring structure having a predetermined functional group (substituents represented by R3 and R4 in the formula (1)) by a well-known and commonly used method.

[0046] In the synthesis of the phenolic compound represented by formula (1), various conditions (such as the catalyst and solvent used, reaction temperature, reaction time, etc.) can be appropriately adjusted according to the raw materials used, etc.

[0047] For example, the compound where n = 1 in formula (1) can be obtained by reacting the compound represented by the following formula (1a) and the compound represented by the following formula (1b) in the presence of hexamethylenetetramine, paraformaldehyde, etc.

[0048] [Chemical formula]

[0049] In formula (1a), R1 and R2 are the same as R1 and R2 in formula (1), respectively.

[0050] [Chemical formula]

[0051] In formula (1b), R3 and R4 are the same as R3 and R4 in formula (1), respectively.

[0052] Also, the compound represented by formula (1) in which R3 and R4 are groups containing a thiol group or an epoxy group can 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.

[0053] Further, the phenolic 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 phenolic compound represented by formula (2) will be described later.

[0054] The phenolic compound represented by formula (1) (for example, the phenolic compound obtained by 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.

[0055] <<Other Phenols>> The raw material phenols for polyphenylene ether may contain conventionally known phenolic compounds (other phenols) other than the phenolic compound represented by formula (1). Examples of conventionally known phenolic compounds other than the phenolic compound represented by formula (1) include phenols that satisfy condition (1) described later and other phenols.

[0056] As described above, when the phenolic compound represented by formula (1) is used as the raw material phenols for polyphenylene ether, the resulting polyphenylene ether will have appropriate reactivity derived from formula (1), and the control of the molecular weight will be facilitated. In addition, the cured film obtained by using such polyphenylene ether is likely to have excellent mechanical properties.

[0057] 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 having high solvent solubility and the like. However, polyphenylene ethers having a branched structure have more polymer terminals having polymerization reactivity than polyphenylene ethers having a linear structure, and it has been found that 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 obtained 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, the polyphenylene ether obtained by using the phenol compound represented by the formula (1) as a raw material for the polyphenylene ether having a branched structure can be easily controlled in molecular weight as described above, and the performance of the obtained cured film can be improved. Therefore, the phenol compound represented by the formula (1) can be particularly preferably used as the raw material phenols for the polyphenylene ether having a branched structure.

[0058] Hereinafter, a polyphenylene ether having a branched structure using the phenol compound represented by the formula (1) as raw material phenols will be described.

[0059] <<<Polyphenylene Ether Having a Branched Structure>>> <<Raw Materials>> The raw material phenols for the polyphenylene ether having a branched structure include the phenol compound represented by the formula (1) and phenols that satisfy at least the following condition 1. (Condition 1) Having hydrogen atoms at the ortho and para positions

[0060] Also, the raw material phenols may contain other phenols.

[0061] Hereinafter, each of the phenols will be described. However, the phenolic compound represented by the formula (1) is as described above.

[0062] The raw material phenols shown below mainly disclose monohydric phenols, but polyhydric phenols may be used as the raw material phenols as long as the effects of the present disclosure are not inhibited.

[0063] <Phenols satisfying at least condition 1> Phenols satisfying at least condition 1 have hydrogen atoms at the ortho and para positions.

[0064] 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

[0065] 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, and the raw material phenols may contain both of these phenols.

[0066] Since the phenols satisfying condition 1 have hydrogen atoms 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, the polyphenylene ether obtained by using such phenols as the raw material phenols can form a branched structure. When phenols satisfying condition 1 are not used, the polyphenylene ether forms a linear structure. More specifically, the polyphenylene ether obtained from the raw material phenols containing phenols satisfying condition 1 will have a part of its structure branched by benzene rings ether-bonded at least at three positions: the ipso position, the ortho position, and the para position. Thus, according to the polyphenylene ether having a branched structure in the backbone, excellent solubility in organic solvents can be obtained.

[0067] In addition, since the phenols satisfying Condition 2 have a functional group containing an unsaturated carbon bond, the polyphenylene ether obtained by using such phenols as raw material phenols has a functional group containing an ethylenic or acetylenic carbon-carbon multiple bond. More specifically, the polyphenylene ether obtained from raw material phenols containing phenols satisfying Condition 2 has a functional group containing an unsaturated carbon bond at least at the meta-position of the benzene ring or at any of two ortho-positions in part of its structure.

[0068] Examples of the 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 the phenols that satisfy Condition 1, only one kind may be used, or two or more kinds may be used.

[0069] Examples of the 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.

[0070] In the synthesis of polyphenylene ether, the content of phenols satisfying 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.

[0071] <Other phenols> Other phenols do not satisfy Condition 1 and are phenols that do not correspond to the phenol compound represented by the formula (1).

[0072] Among other phenols, those satisfying Condition 2 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. Among other phenols, those not satisfying Condition 2 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.

[0073] In addition, as other phenols, phenols having no hydrogen atom at either the para position or the ortho position may be used.

[0074] Other phenols may be used alone or in combination of two or more.

[0075] In the synthesis of polyphenylene ether, when using other phenols, the content ratio of other phenols 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.

[0076] <<<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.

[0077] 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. Also, by increasing the ratio of the phenolic compound represented by formula (1) in the raw material phenols and the ratio of phenols having no hydrogen atoms at the para and ortho positions 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.

[0078] <<<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 used and the ratio of the raw material phenols 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 by the same method except that phenols satisfying condition 1 are not used.

[0079] 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. in addition to the above-mentioned raw material phenols (such as the phenol compound represented by formula (1)), as disclosed in International Publication No. 2020 / 017570.

[0080] Examples of the catalyst include amine compounds, metal amine compounds composed of heavy metal compounds such as copper, manganese, cobalt, etc. and amine compounds such as tetramethylethylenediamine. In particular, in order to obtain a copolymer with 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 kind of catalyst may be used, or two or more kinds may be used.

[0081] The content of the catalyst is not particularly limited, but it may be, for example, 0.1 to 0.6 mol% based on the total amount of the raw material phenols in the composition for synthesizing polyphenylene ether.

[0082] 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), etc. Only one kind of solvent may be used, or two or more kinds may be used. In addition, the solvent may contain water or a solvent miscible with water. The content of the solvent in the composition for synthesizing polyphenylene ether is not particularly limited and may be adjusted as appropriate.

[0083] <<<<Curable Composition>>>> The curable composition of the present disclosure contains polyphenylene ether synthesized using raw phenols containing at least a phenolic compound represented by formula (1). The curable composition may also contain other components.

[0084] 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.

[0085] Examples of other components include inorganic fillers such as silica, peroxides, crosslinking type curing agents, polyphenylene ethers other than the polyphenylene ether according to this 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 preventives, adhesion imparting agents and other additives.

[0086] Other components may be appropriately selected according to uses 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.

[0087] 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.

[0088] When the content of 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.

[0089] 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.

[0090] 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.

[0091] 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.

[0092] <<<<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 base material.

[0093] 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.

[0094] As the film materials for the carrier film and the cover film, any known materials used for dry films can be used.

[0095] As the carrier film, for example, a thermoplastic film such as a polyester film like polyethylene terephthalate with a thickness of 2 to 150 μm is used.

[0096] 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.

[0097] 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.

[0098] The prepreg can be obtained, for example, by impregnating a curable composition into a substrate such as a glass cloth and drying it.

[0099] <<<<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.

[0100] 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.

[0101] 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 by 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 by an inert gas oven, a hot plate, a vacuum oven, a vacuum press machine, or the like) is carried out to cure the resin layer.

[0102] 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.

[0103] <<<<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 for various purposes as a material constituting a laminate or an electronic component.

[0104] 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 systems).

Examples

[0105] <<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) to obtain the phenolic compound (4DT-26DMP) represented by formula (2) (28.9 g, 84.2 mmol) as a white powder with a yield of 92%. Figure 1 shows the 1 1H-NMR spectrum (400 MHz, CDCl3, room temperature).

[0106]

Chemical formula

[0107] <<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.

[0108] <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.

[0109] <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.

[0110] <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.

[0111] <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%.

[0112] <<<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.

[0113]

Table 1

[0114]

Table 2

[0115] As shown in Tables 1 and 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 moderate compared to PPE-1. On the other hand, for PPE-1, when the reaction time was prolonged, 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 is suppressed in PPE-DT-1 to PPE-DT-3, it is understood that it is easy to produce polyphenylene ether in the desired molecular weight range and that it is more likely to have excellent storage stability.

[0116] <<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.

[0117] <Production of cured film> 100 parts by mass of each polyphenylene ether, 50 parts by mass of a crosslinking 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).

[0118] <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.

[0119] <Dielectric constant> A sample to be measured, cut into a length of 80 mm and a width of 45 mm, was used as a test piece, and the relative permittivity 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.

[0120] <Tensile properties> The sample to be measured was cut into 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 Test speed: 1 mm / min Elongation calculation: (Tensile movement amount / Distance between chucks) × 100

[0121]

Table 3

[0122] 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 confirmed that they are also excellent in permittivity.

Industrial applicability

[0123] The polyphenylene ether according to the present invention suppresses a rapid increase in molecular weight and is useful as a material for forming a cured film constituting electronic components and the like because it is easy to stably manufacture a cured film having excellent performance.

Claims

Claim 1 A polyphenylene ether obtained from raw material phenols, wherein the raw material phenols include phenols represented by the following formula (1), the polyphenylene ether. 【Chemical 1】 In the formula, 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 containing an unsaturated double bond, a thiol group, and an epoxy group. Claim 2 The polyphenylene ether according to claim 1, wherein the phenols represented by the formula (1) are phenols represented by the following formula (2). 【Chemical 2】 Claim 3 The polyphenylene ether according to claim 1, wherein the raw material phenols include, in addition to the phenols represented by the formula (1), at least phenols satisfying the following condition 1. (Condition 1) Having hydrogen atoms at the ortho and para positions Claim 4 A curable composition containing the polyphenylene ether according to claim 1 or 2. Claim 5 A dry film or prepreg, characterized in that it is obtained by applying or impregnating the curable composition according to claim 4 to a substrate. Claim 6 A cured product, characterized in that it is obtained by curing the curable composition according to claim 4. Claim 7 A laminate, characterized in that it contains the cured product according to claim 6. Claim 8 An electronic component, characterized in that it has the cured product according to claim 6.

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