JP7350547B2 - Curable compositions, dry films, cured products, electronic components and polyphenylene ether - Google Patents

Description

Application of Article 30, Paragraph 2 of the Patent Act (1) Public Interest Incorporated Association, Society of Polymer Science, Proceedings of the Society of Polymer Science, Volume 68, No. 1 [2019] Published on May 14, 2020 (2) Date of the conference: Reiwa 1 May 30th, 68th Annual Meeting of the Society of Polymer Science and Technology

The present invention relates to a curable composition, a dry film, a cured product, an electronic component, and a polyphenylene ether.

With the spread of high-capacity, high-speed communications typified by fifth-generation communication systems (5G) and millimeter-wave radar for automotive ADAS (Advanced Driving Systems), the frequency of communications equipment signals has progressed toward higher frequencies.

However, when conventional epoxy resins are used as wiring board materials, the dielectric constant (Dk) and dielectric loss tangent (Df) are not low enough, so the transmission loss due to dielectric loss increases as the frequency increases. Problems such as signal attenuation and heat generation were occurring. Therefore, polyphenylene ether, which has excellent low dielectric properties, has been used, but since polyphenylene ether is a thermoplastic resin, it has a problem with heat resistance.

As a means to solve this problem, Non-Patent Document 1 proposes to introduce an allyl group into the molecule of polyphenylene ether to produce a thermosetting resin.

J. Nunoshige, H. Akahoshi, Y. Shibasaki, M. Ueda, J. Polym. Sci. Part A: Polym. Chem. 2008, 46, 5278-5282.

However, the solvents in which polyphenylene ether can be dissolved are limited, and the polyphenylene ether obtained by the method of Non-Patent Document 1 is also soluble only in highly toxic solvents such as chloroform and toluene. Therefore, there has been a problem in that it is difficult to handle the resin varnish and control exposure to solvents in the process of forming and curing the resin varnish into a coating film, such as in wiring board applications.

Furthermore, in recent years, millimeter-wave module boards that are hybrid (composite) high-frequency materials on a general-purpose base material (FR-4) have been increasing in order to reduce costs. In order to hybridize with the general-purpose FR-4 material, it is desirable to use a material that can be laminated at low temperatures (200° C. or lower, preferably 180° C. or lower).

Furthermore, insulating films for electronic components are required to have excellent tensile properties in order to prevent problems such as a decrease in handleability as a cured film and the occurrence of cracks after heating and cooling cycles. .

Therefore, the object of the present invention is to maintain low dielectric properties, to be soluble in various solvents (organic solvents other than highly toxic organic solvents, such as cyclohexanone), to have excellent low-temperature curability, and to obtain a cured product. An object of the present invention is to provide a polyphenylene ether-containing curable composition whose film has excellent tensile properties.

The inventors of the present invention have conducted extensive research toward achieving the above object. As a result, they discovered that the above problems could be solved by creating a curable composition containing specific components, and completed the present invention.

The present invention (1) is a curable composition comprising a side chain epoxidized polyphenylene ether and another polyphenylene ether different from the side chain epoxidized polyphenylene ether,
The side chain epoxidized polyphenylene ether is a phenol (A) that satisfies at least the following conditions 1 and 2, or a phenol (B) that satisfies at least the following condition 1 and does not satisfy the following condition 2, and the following condition 1. A polyphenylene ether made of raw material phenols containing a mixture of phenols (C) that does not satisfy the following conditions 2 and satisfies condition 2 below, in which part or all of the side chain unsaturated carbon bonds are epoxidized,
and/or The other polyphenylene ether is a phenol (A) that satisfies at least both Condition 1 and Condition 2 below, or a phenol (B) that satisfies at least Condition 1 below but does not satisfy Condition 2 below, and the following conditions. It is made of raw material phenols containing a mixture of phenols (C) that do not satisfy condition 1 but satisfy condition 2 below,
It is a curable composition.
(Condition 1)
Has hydrogen atoms at the ortho and para positions (condition 2)
Has a hydrogen atom in the para position and a functional group containing an unsaturated carbon bond

The invention (1) preferably includes:
A curable composition comprising a side chain epoxidized polyphenylene ether and another polyphenylene ether different from the side chain epoxidized polyphenylene ether,
The side chain epoxidized polyphenylene ether is a phenol (A) that satisfies at least the following conditions 1 and 2, or a phenol (B) that satisfies at least the following condition 1 and does not satisfy the following condition 2, and the following condition 1. A part of the unsaturated carbon bonds in the side chain of polyphenylene ether, which is made of raw material phenols containing a mixture of phenols (C) that do not satisfy the following conditions 2 and has a slope calculated by a conformation plot of less than 0.6. or completely epoxidized,
and/or The other polyphenylene ether is a phenol (A) that satisfies at least both Condition 1 and Condition 2 below, or a phenol (B) that satisfies at least Condition 1 below but does not satisfy Condition 2 below, and the following conditions. It is made of raw material phenols containing a mixture of phenols (C) that do not satisfy condition 1 but satisfy condition 2 below, and has a slope calculated by a conformation plot of less than 0.6,
It is a curable composition.
(Condition 1)
Has hydrogen atoms at the ortho and para positions (condition 2)
Has a hydrogen atom in the para position and a functional group containing an unsaturated carbon bond

The present invention (2) is the curable composition of the present invention (1), further comprising an epoxy group-reactive crosslinked curing agent.

The present invention (3) is a dry film or prepreg obtained by applying the curable composition of the present invention (1) or (2) to a substrate.

The present invention (4) is a cured product obtained by curing the curable composition of the present invention (1) or (2).

The present invention (5) is a laminate containing the cured product of the present invention (4).

The present invention (6) is an electronic component having the cured product of the present invention (4).

According to the present invention, while maintaining low dielectric properties, it is soluble in various solvents (organic solvents other than highly toxic organic solvents, such as cyclohexanone), has excellent low-temperature curability, and can be obtained by curing. It becomes possible to provide a polyphenylene ether-containing curable composition whose film has excellent tensile properties.

In this application, the entire description of Japanese Patent Application No. 2018-134338 is cited and incorporated.

In addition, when isomers exist in the described compound, all possible isomers can be used in the present invention unless otherwise specified.

Furthermore, in the present invention, an "unsaturated carbon bond" refers to an ethylenic or acetylenic carbon-carbon multiple bond (double bond or triple bond) unless otherwise specified.

In the present invention, when describing raw material phenols, when expressed as "ortho position", "para position", etc., unless otherwise specified, the position of the phenolic hydroxyl group is the standard (ipso position).

In the present invention, when simply expressed as "ortho position" or the like, it means "at least one of the ortho positions" or the like. Therefore, unless there is a particular contradiction, simply "ortho position" may be interpreted as indicating either ortho position, or both ortho positions.

In the present invention, phenols that are used as raw materials for polyphenylene ether (PPE) and can be constituent units of polyphenylene ether are collectively referred to as "raw material phenols."

<<Curable composition>>
The curable composition of the present invention (sometimes simply referred to as a composition) comprises a side chain epoxidized polyphenylene ether and other polyphenylene ethers (non-side chain epoxidized polyphenylene ethers having a side chain unsaturated carbon bond). polyphenylene ether).

One or both of the side chain epoxidized polyphenylene ether and other polyphenylene ether have a branched structure. More specifically, the curable composition of the present invention is in one of the following forms.
(1) A composition comprising a side chain epoxidized polyphenylene ether that does not have a branched structure and a non-side chain epoxidized polyphenylene ether that has a side chain unsaturated carbon bond and a branched structure.
(2) A composition comprising a side chain epoxidized polyphenylene ether having a branched structure and a non-side chain epoxidized polyphenylene ether having a side chain unsaturated carbon bond and no branched structure.
(3) A composition comprising a side chain epoxidized polyphenylene ether having a branched structure and a non-side chain epoxidized polyphenylene ether having a side chain unsaturated carbon bond and a branched structure.

By combining side chain epoxidized polyphenylene ether and other polyphenylene ethers in this way, it is possible to obtain a cured product with excellent mechanical properties such as tensile properties, and the composition is soluble in a solvent such as cyclohexanone. . From the viewpoint of excellent solvent resistance of the cured product, an embodiment in which both have a branched structure is particularly preferred. In the present invention, a polyphenylene ether having a branched structure may be referred to as a branched polyphenylene ether, and a polyphenylene ether having no branched structure may be referred to as a linear polyphenylene ether.

In the present invention, the solid content of the composition means the components constituting the composition other than the solvent (particularly the organic solvent), or the mass or volume thereof.

<Side chain epoxidized polyphenylene ether>
Side chain epoxidized polyphenylene ether is obtained by epoxidizing a part or all of the side chain unsaturated carbon bonds of polyphenylene ether having unsaturated carbon bonds in the side chain. The side chain unsaturated carbon bond typically originates from an unsaturated carbon bond that the raw material phenol, which is a constituent unit of polyphenylene ether, has as a substituent.

In the side chain epoxidized polyphenylene ether of the present invention, part or all of the side chain unsaturated carbon bonds are epoxidized. Therefore, a cured product with better low dielectric properties and solvent resistance can be obtained. Moreover, by epoxidizing, the thermosetting temperature can be made relatively low.

The number average molecular weight of the side chain epoxidized polyphenylene ether is preferably 1,000 to 20,000 or 1,000 to 10,000. Further, the polydispersity index (PDI: weight average molecular weight/number average molecular weight) is preferably 1.5 to 20.

In the present invention, the number average molecular weight and weight average molecular weight are measured by gel permeation chromatography (GPC) and converted using a calibration curve prepared using standard polystyrene.

The epoxidation rate of the side chain epoxidized polyphenylene ether is at least 1% and at most 100%. By adjusting it within this range, low dielectric properties and solvent resistance can be ensured.

The epoxidation rate of side chain epoxidized polyphenylene ether is the ratio of the number of side chain epoxy groups to the total number of side chain unsaturated carbon bonds and the number of side chain epoxy groups that the polyphenylene ether has. Each number can be analyzed using 1H NMR (400MHz, CDCl3, TMS).

The side chain epoxidized polyphenylene ether of the present invention is typically obtained by epoxidizing some or all of the side chain unsaturated carbon bonds in a polyphenylene ether having side chain unsaturated carbon bonds with an epoxidizing agent. It will be done.

The type of epoxidizing agent, reaction temperature, reaction time, presence or absence of a catalyst, type of catalyst, etc. can be appropriately designed. Two or more types of compounds may be used as epoxidizing agents.

The epoxidizing agent is not particularly limited as long as it can epoxidize unsaturated carbon bonds. Typically, organic peracids are mentioned. Examples of organic peracids include percarboxylic acids. Examples of percarboxylic acids include performic acid, peracetic acid, perpropionic acid, trifluoroperacetic acid, perbenzoic acid, and m-chloroperbenzoic acid.

Note that the terminal phenolic hydroxyl group of the side chain epoxidized polyphenylene ether may be epoxidized with a predetermined epoxidizing agent. Such epoxidizing agents include epihalohydrins such as epichlorohydrin and epibromohydrin.

Polyphenylene ether having a side chain unsaturated carbon bond is obtained by oxidative polymerization of raw material phenols containing as an essential component a phenol that satisfies the following conditions.
(conditions)
Has a hydrogen atom in the para position and a functional group containing an unsaturated carbon bond

A preferred side chain epoxidized polyphenylene ether is one obtained by epoxidizing a polyphenylene ether (described later) having a branched structure and a side chain unsaturated carbon bond. Since it has a branched structure, the polyphenylene ether and the side chain epoxidized polyphenylene ether derived therefrom are soluble in various solvents such as cyclohexanone.

<Other polyphenylene ethers>
The composition of the present invention contains other polyphenylene ethers different from the above-mentioned side chain epoxidized polyphenylene ethers. In other words, other polyphenylene ethers are polyphenylene ethers (non-side chain epoxidized polyphenylene ethers) that do not correspond to side chain epoxidized polyphenylene ethers.

Another preferable polyphenylene ether is a polyphenylene ether having a branched structure and an unsaturated carbon bond in a side chain (this will be described later). Since it has a branched structure, the polyphenylene ether is soluble in various solvents such as cyclohexanone.

When the other polyphenylene ether does not have a branched structure, its number average molecular weight is preferably from 1,000 to 20,000 or from 1,000 to 10,000. Further, the polydispersity index (PDI: weight average molecular weight/number average molecular weight) is preferably 1.5 to 20.

When the other polyphenylene ether has a branched structure, its number average molecular weight is preferably from 2,000 to 30,000. Further, the polydispersity index (PDI: weight average molecular weight/number average molecular weight) is preferably 1.5 to 20.

The amount of other polyphenylene ethers may be 200 to 1000 parts by mass based on 100 parts by mass of the side chain epoxidized polyphenylene ether. In other words, the amount of other polyphenylene ethers may be 70 to 90% by mass based on the total solid content of the composition. Within the above range, good curability, moldability, and chemical resistance can be achieved in a well-balanced manner.

(Branched polyphenylene ether with unsaturated carbon bond in side chain)
Polyphenylene ether having a branched structure and having an unsaturated carbon bond in a side chain is (form 1) a raw material phenol containing as an essential component a phenol (A) that satisfies at least the following conditions 1 and 2; Or (Form 2) A raw material containing as an essential component a mixture of at least a phenol (B) that satisfies the following condition 1 but does not satisfy the following condition 2 and a phenol (C) that does not satisfy the following condition 1 but satisfies the following condition 2. It is obtained by oxidative polymerization of phenols.
(Condition 1)
Has hydrogen atoms at the ortho and para positions (condition 2)
Has a hydrogen atom in the para position and a functional group containing an unsaturated carbon bond

Here, phenols that satisfy condition 1 {for example, phenols (A) and phenols (B)} have a hydrogen atom at the ortho position, so when oxidatively polymerized with phenols, the phenols have hydrogen atoms at the ipso and para positions. In addition, an ether bond can be formed at the ortho position, making it possible to form a branched structure.

When phenols that do not satisfy Condition 1 {for example, phenols (C) and the following phenols (D)} are oxidatively polymerized, ether bonds are formed at the ipso and para positions, and they are polymerized in a linear chain. It will be done.

Moreover, phenols {for example, phenols (A) and phenols (C)} that satisfy Condition 2 have a hydrocarbon group containing at least an unsaturated carbon bond. Therefore, polyphenylene ether synthesized using phenols satisfying condition 2 as a raw material has a hydrocarbon group containing an unsaturated carbon bond as a functional group, and thus has crosslinking properties.

In this manner, a portion of the structure of such polyphenylene ether is branched by benzene rings having ether bonds at least at three positions: ipso, ortho, and para positions. Such polyphenylene ether is, for example, a polyphenylene ether having at least a branched structure as shown by formula (5) in the skeleton, and a compound having a hydrocarbon group containing at least one unsaturated carbon bond as a functional group. Conceivable.

In formula (5), R _a to R _k are hydrogen atoms or hydrocarbon groups having 1 to 15 carbon atoms (preferably 1 to 12 carbon atoms). However, at least one of R _a to R _k is a hydrocarbon group having an unsaturated carbon bond.

Next, Form 1 may further contain phenols (B) and/or phenols (C) as the raw material phenols. Moreover, the above-mentioned form 2 may be a form that further contains phenol (A) as the raw material phenol.

It is preferable that such polyphenylene ether is in Form 2, or in Form 1, which further contains phenols (B) and/or phenols (C) as an essential component.

Further, the raw material phenols may contain other phenols within a range that does not impede the effects of the present invention.

Examples of other phenols include phenols (D), which are phenols that have a hydrogen atom at the para position, no hydrogen atom at the ortho position, and no functional group containing an unsaturated carbon bond. It will be done.

In both Form 1 and Form 2 above, it is preferable to further include phenols (D) as raw material phenols in order to increase the molecular weight of such polyphenylene ether.

It is most preferable that such polyphenylene ether further contains phenol (D) as the raw material phenol in Form 2 above.

Furthermore, in the above-mentioned form 2, from an industrial and economic point of view, the phenol (B) is at least one of o-cresol, 2-phenylphenol, 2-dodecylphenol, and phenol; Preferably (C) is 2-allyl-6-methylphenol.

The phenols (A) to (D) will be explained in more detail below.

As mentioned above, phenols (A) are phenols that satisfy both Conditions 1 and 2, that is, phenols that have hydrogen atoms at the ortho and para positions and a functional group containing an unsaturated carbon bond. and preferably a phenol (a) represented by the following formula (1).

In formula (1), R ₁ to R ₃ are hydrogen atoms or hydrocarbon groups having 1 to 15 carbon atoms. However, at least one of R ₁ to R ₃ is a hydrocarbon group having an unsaturated carbon bond. Note that, from the viewpoint of facilitating polymerization during oxidative polymerization, the hydrocarbon group preferably has 1 to 12 carbon atoms.

The phenols (a) represented by formula (1) 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- Examples include allyl-5-ethylphenol. Only one type of phenols represented by formula (1) may be used, or two or more types may be used.

As mentioned above, the phenol (B) is a phenol that satisfies condition 1 and does not satisfy condition 2, that is, it has hydrogen atoms at the ortho and para positions and does not have a functional group containing an unsaturated carbon bond. It is a phenol, preferably a phenol (b) represented by the following formula (2).

In formula (2), R ₄ to R ₆ are hydrogen atoms or hydrocarbon groups having 1 to 15 carbon atoms. However, R ₄ to R ₆ do not have an unsaturated carbon bond. Note that, from the viewpoint of facilitating polymerization during oxidative polymerization, the hydrocarbon group preferably has 1 to 12 carbon atoms.

The phenols (b) represented by formula (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. The phenols represented by formula (2) may be used alone or in combination of two or more.

As mentioned above, phenols (C) are phenols that do not satisfy condition 1 but satisfy condition 2, that is, have a hydrogen atom in the para position, do not have a hydrogen atom in the ortho position, and have an unsaturated carbon bond. A phenol having a functional group containing the following, preferably a phenol (c) represented by the following formula (3).

In formula (3), R ₇ and R ₁₀ are hydrocarbon groups having 1 to 15 carbon atoms, and R ₈ and R ₉ are hydrogen atoms or hydrocarbon groups having 1 to 15 carbon atoms. However, at least one of R ₇ to R ₁₀ is a hydrocarbon group having an unsaturated carbon bond. Note that, from the viewpoint of facilitating polymerization during oxidative polymerization, the hydrocarbon group preferably has 1 to 12 carbon atoms.

The phenols (c) represented by formula (3) include 2-allyl-6-methylphenol, 2-allyl-6-ethylphenol, 2-allyl-6-phenylphenol, and 2-allyl-6-styrylphenol. , 2,6-divinylphenol, 2,6-diallylphenol, 2,6-diisopropenylphenol, 2,6-dibutenylphenol, 2,6-diisobutenylphenol, 2,6-diisopentenylphenol, 2 Examples include -methyl-6-styrylphenol, 2-vinyl-6-methylphenol, and 2-vinyl-6-ethylphenol. Only one type of phenol represented by formula (3) may be used, or two or more types may be used.

As mentioned above, the phenol (D) is a phenol having a hydrogen atom at the para position, no hydrogen atom at the ortho position, and no functional group containing an unsaturated carbon bond, and is preferably one of the following: It is a phenol (d) represented by formula (4).

In formula (4), R ₁₁ and R ₁₄ are hydrocarbon groups having 1 to 15 carbon atoms having no unsaturated carbon bond, and R ₁₂ and R ₁₃ are hydrogen atoms or having no unsaturated carbon bond. It is a hydrocarbon group having 1 to 15 carbon atoms. Note that, from the viewpoint of facilitating polymerization during oxidative polymerization, the hydrocarbon group preferably has 1 to 12 carbon atoms.

The phenols (d) represented by formula (4) 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, and 2,6-ditolylphenol. Only one type of phenol represented by formula (4) may be used, or two or more types may be used.

Here, in the present invention, examples of the hydrocarbon group include an alkyl group, a cycloalkyl group, an aryl group, an alkenyl group, an alkynyl group, and preferably an alkyl group, an aryl group, and an alkenyl group. Examples of the hydrocarbon group having an unsaturated carbon bond include an alkenyl group and an alkynyl group. Note that these hydrocarbon groups may be linear or branched.

Furthermore, other phenols may include phenols that do not have a hydrogen atom at the para position.

It is preferable that the proportion of phenols satisfying condition 1 to the total of raw material phenols is 1 to 50 mol%.

The proportion of phenols satisfying condition 2 relative to the total raw material phenols is preferably 0.5 to 99 mol%, more preferably 1 to 99 mol%.

The number average molecular weight of polyphenylene ether obtained by oxidative polymerization of the raw material phenols as described above by a known and conventional method is preferably 2,000 to 30,000. It is more preferably from 5,000 to 30,000, even more preferably from 8,000 to 30,000, and particularly preferably from 8,000 to 25,000. Further, the polydispersity index (PDI: weight average molecular weight/number average molecular weight) is preferably 1.5 to 20. Note that the number average molecular weight and weight average molecular weight were measured by gel permeation chromatography (GPC) and converted using a calibration curve prepared using standard polystyrene.

The hydroxyl value of such polyphenylene ether may be 7.0 or more when the number average molecular weight (Mn) is 10,000 or more. In other words, when the number average molecular weight (Mn) is 5,000 or more, it may be 14.0 or more, and when the number average molecular weight (Mn) is 20,000 or more, the hydroxyl value of such polyphenylene ether is It may be 3.5 or more.

Such polyphenylene ether has a weight average molecular weight (Mw) of 130,000 or more and a solution viscosity of 250 or less (P) when dissolved in chloroform at a concentration of 0.5 (g/mL). It is preferable that there be. Further, when the weight average molecular weight (Mw) is 35,000 or more and the concentration is 0.5 (g/mL), it is preferable that the solution viscosity is 250 or less (P).

1 g of such polyphenylene ether is preferably soluble in 100 g of cyclohexanone (more preferably in 100 g of cyclohexanone, DMF and PMA) at 25°C. Note that 1 g of polyphenylene ether is soluble in 100 g of a solvent (for example, cyclohexanone) means that turbidity and precipitation cannot be visually confirmed when 1 g of polyphenylene ether and 100 g of a solvent are mixed. It is more preferable that such polyphenylene ether is soluble in 1 g or more in 100 g of cyclohexanone at 25°C.

Here, the branched structure (degree of branching) of polyphenylene ether can be confirmed based on the following analysis procedure.

<Analysis procedure>
After preparing chloroform solutions of polyphenylene ether at intervals of 0.1, 0.15, 0.2, and 0.25 mg/mL, a graph of the refractive index difference and concentration was created while feeding the solution at 0.5 mL/min. , calculate the refractive index increment dn/dc from the slope. Next, the absolute molecular weight is measured under the following device operating conditions. With reference to the chromatogram of the RI detector and the chromatogram of the MALS detector, a regression line is determined by the least squares method from a logarithmic graph (conformation plot) of molecular weight and radius of gyration, and its slope is calculated.

<Measurement conditions>
Equipment name: HLC8320GPC
Mobile phase: Chloroform column: TOSOH TSKguardcolumnHHR-H
+TSKgelGMHHR-H (2 pieces)
+TSKgelG2500HHR
Flow rate: 0.6mL/min.
Detector: DAWN HELEOS (MALS detector)
+Optilab rEX (RI detector, wavelength 254 nm)
Sample concentration: 0.5mg/mL
Sample solvent: Same as mobile phase. Dissolve 5 mg of sample in 10 mL of mobile phase Injection volume: 200 μL
Filter: 0.45μm
STD reagent: Standard polystyrene Mw 37,900
STD concentration: 1.5mg/mL
STD solvent: Same as mobile phase. Dissolve 15 mg of sample in 10 mL of mobile phase Analysis time: 100 min

In resins having the same absolute molecular weight, the more branching of the polymer chain progresses, the smaller the distance (radius of rotation) from the center of gravity to each segment. Therefore, the slope of the logarithmic plot of the absolute molecular weight and radius of gyration obtained by GPC-MALS indicates the degree of branching, and the smaller the slope, the more advanced the branching is. In the present invention, the smaller the slope calculated by the above conformation plot, the more branches the polyphenylene ether has, and the larger the slope, the less branches the polyphenylene ether has.

In the polyphenylene ether having a branched structure, the slope is, for example, less than 0.6, preferably 0.55 or less, 0.50 or less, 0.45 or less, or 0.40 or less. When the above slope is within this range, it is considered that the polyphenylene ether has sufficient branching. Note that the lower limit of the above-mentioned slope is not particularly limited, but is, for example, 0.05 or more, 0.10 or more, 0.15 or more, or 0.20 or more.

Note that the slope of the conformation plot can be adjusted by changing the temperature, amount of catalyst, stirring speed, reaction time, amount of oxygen supply, and amount of solvent during synthesis of polyphenylene ether. More specifically, the slope of the conformation plot can be reduced by increasing the temperature, increasing the amount of catalyst, increasing the stirring speed, increasing the reaction time, increasing the amount of oxygen supplied, and/or decreasing the amount of solvent. (polyphenylene ether tends to branch more easily).

Here, the polyphenylene ether that does not have a branched structure and has an unsaturated carbon bond in a side chain contains, for example, a phenol (C) and, if necessary, a phenol (D), and a phenol (A) and a phenol. It can be produced in the same manner as in the production of branched polyphenylene ether having a side chain unsaturated carbon bond, except that raw phenols containing no (B) are used.

<Other ingredients>
The curable composition preferably contains a peroxide and/or epoxy group-reactive crosslinking curing agent. Further, the curable composition may contain other components within a range that does not impede the effects of the present invention.

The peroxide has the effect of promoting a crosslinking reaction between unsaturated carbon bonds that may be contained in the side chain epoxidized polyphenylene ether and contained in other polyphenylene ethers.

Examples of peroxides include methyl ethyl ketone peroxide, methyl acetoacetate peroxide, acetylacetoperoxide, 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- Toluyl peroxide, diisopropyl peroxydicarbonate, t-butylene peroxybenzoate, di-t-butyl peroxide, t-butylperoxyisopropyl monocarbonate, α,α'-bis(t-butylperoxy-m-isopropyl) Examples include benzene, etc. Only one kind of peroxide may be used, or two or more kinds of peroxides may be used.

Among these peroxides, those having a 1-minute half-life temperature of 130° C. to 180° C. are desirable from the viewpoint of ease of handling and reactivity. Since such peroxides have a relatively high reaction initiation temperature, they are difficult to accelerate curing at a time when curing is not necessary, such as during drying, and do not impair the storage stability of the polyphenylene ether resin composition, and also reduce volatility. Because of its low value, it does not volatilize during drying or storage, and has good stability.

The amount of peroxide added is preferably 0.01 to 20 parts by mass, and 0.05 to 10 parts by mass, based on the total amount of peroxide, based on 100 parts by mass of solid content of the curable composition. The amount is more preferably 0.1 to 10 parts by mass, and particularly preferably 0.1 to 10 parts by mass. By setting the total amount of peroxide within this range, it is possible to obtain sufficient effects at low temperatures and to prevent deterioration of film quality when formed into a coating.

Further, if necessary, an azo compound such as azobisisobutyronitrile or azobisisovaleronitrile or a radical initiator such as dicumyl or 2,3-diphenylbutane may be contained.

The epoxy group-reactive crosslinking type curing agent is particularly one that three-dimensionally crosslinks side chain epoxidized polyphenylene ether.

The epoxy group-reactive crosslinked curing agent according to the present invention is not limited as long as it is a crosslinked curing agent that is commonly used with epoxy resins. Examples of such epoxy group-reactive crosslinking curing agents include compounds having a plurality of reactive groups in one molecule, such as an amino group, a carboxyl group, an acid anhydride group, a phenolic hydroxyl group, a thiol group, and an ester group. It will be done. More specifically, examples include amide curing agents, amine curing agents, phenol curing agents, imidazole curing agents, acid anhydride curing agents, and ester curing agents. Only one type of epoxy group-reactive crosslinked curing agent may be used, or two or more types may be used.

Examples of the amide curing agent include dicyandiamide and aliphatic polyamide.

Examples of the amine curing agent include diethylenetriamine, triethylenetetramine, tetraethylenepentamine, pentaethylenehexamine, metaxylenediamine, isophoronediamine, norbornenediamine, 1,3-bisaminomethylcyclohexane, N-aminoethylpiperazine, diaminodiphenylmethane, m-phenylenediamine, p-phenylenediamine, ammonia, triethylamine, diethylamine, 3,3'-diaminodiphenylsulfone, 4,4'-diaminodiphenylsulfone, 4,4'-diaminodiphenylmethane, 4,4'-diaminodiphenyl ether Can be mentioned.

Examples of the phenolic curing agent include bisphenol A, bisphenol F, phenol novolak resin, cresol novolak resin, and p-xylene novolak resin.

Specific examples of imidazole curing agents include 2-methylimidazole, 2-ethyl-4-methylimidazole, 2-phenylimidazole, 2-phenyl-4-methyl-5-hydroxymethylimidazole, and the like.

Examples of acid anhydride curing agents include phthalic anhydride, trimellitic anhydride, pyromellitic anhydride, tetrahydrophthalic anhydride, methyltetrahydrophthalic anhydride, hexahydrophthalic anhydride, methylhexahydrophthalic anhydride, and methylnadic anhydride. , dodecylsuccinic anhydride, chlorendic anhydride, benzophenonetetracarboxylic anhydride, ethylene glycol bis(anhydrotrimate), and methylcyclohexenetetracarboxylic anhydride.

As the epoxy group-reactive crosslinked curing agent, an ester curing agent having two or more ester groups in one molecule is particularly preferred. Many curing agents generate hydroxyl groups when they react with epoxy groups, which may adversely affect dielectric properties and the like. On the other hand, since ester curing agents do not produce hydroxyl groups when reacting with epoxy groups, the cured product can exhibit good dielectric properties. The ester curing agent can be obtained by a condensation reaction between a carboxylic acid compound and a hydroxy compound.

Examples of carboxylic acid compounds include acetic acid, propionic acid, fluoroacetic acid, benzoic acid, nitrobenzoic acid, chlorobenzoic acid, thiobenzoic acid, adipic acid, sebacic acid, succinic acid, maleic acid, itaconic acid, 1,2,3, Examples include 4-butanetetracarboxylic acid, phthalic acid, isophthalic acid, terephthalic acid, benzenetricarboxylic acid, and benzenetetracarboxylic acid.

Ester-based curing agents obtained using a phenol compound or a naphthol compound as the hydroxy compound are preferred. Examples of phenolic compounds or naphthol compounds include hydroquinone, resorcinol, bisphenol A, bisphenol F, bisphenol S, phenolphthalin, methylated bisphenol A, methylated bisphenol F, methylated bisphenol S, phenol, o-cresol, m-cresol, p-cresol, catechol, α-naphthol, β-naphthol, 1,5-dihydroxynaphthalene, 1,6-dihydroxynaphthalene, 2,6-dihydroxynaphthalene, dihydroxybenzophenone, trihydroxybenzophenone, tetrahydroxybenzophenone, phloroglucin, benzenetriol , dicyclopentadienyl diphenol, phenol novolak, and the like.

Ester curing agents generally include compounds having two or more ester groups with high reaction activity in one molecule, such as phenol esters, thiophenol esters, N-hydroxyamine esters, and esters of heterocyclic hydroxy compounds. Preferably used. Commercially available active ester compounds include active ester compounds containing a dicyclopentadiene-type diphenol condensation structure, active ester compounds containing a naphthalene structure, active ester compounds containing an acetylated product of phenol novolac, and benzoylated products of phenol novolak. There are active ester compounds, etc.

Specifically, EXB9451, EXB9460, HPC8000-65T (manufactured by DIC Corporation, active group equivalent weight: approximately 223) as active ester compounds containing a dicyclopentadiene type diphenol condensed structure, and active ester compounds containing an acetylated product of phenol novolac. DC808 (manufactured by Mitsubishi Chemical Corporation, active group equivalent: approximately 149), YLH1026 (manufactured by Mitsubishi Chemical Corporation, active group equivalent: approximately 200), YLH1030 (manufactured by Mitsubishi Chemical Corporation, active group equivalent) containing benzoylated phenol novolak. YLH1048 (manufactured by Mitsubishi Chemical Corporation, active group equivalent: about 245), 2,2-bis(4-acetoxyphenyl)propane (active ester group equivalent: about 156), and the like.

The amount of the epoxy group-reactive crosslinked curing agent may be 5 to 50 parts by weight per 100 parts by weight of the side chain epoxidized polyphenylene ether. In other words, the amount of the epoxy group-reactive crosslinked curing agent may be 1 to 10% by mass based on the total solid content of the composition. Within the above range, toughness, heat resistance, etc. can be achieved in a well-balanced manner.

The curable composition is usually provided or used in a state in which polyphenylene ether is dissolved in a solvent. Preferred side chain epoxidized polyphenylene ethers and other preferred polyphenylene ethers have higher solubility in solvents than conventional polyphenylene ethers, allowing a wide range of solvent choices to be used depending on the application of the curable composition. be able to.

Examples of solvents that can be used in the curable composition of the present invention include conventionally usable solvents such as chloroform, methylene chloride, and toluene, as well as N,N-dimethylformamide (DMF) and 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, and other relatively safe solvents. Only one type of solvent may be used, or two or more types may be used.

The content of the solvent in the curable composition is not particularly limited, and can be adjusted as appropriate depending on the use of the curable composition.

The curable composition may contain known and commonly used raw materials such as resins other than the above-mentioned polyphenylene ether and other additives within a range that does not impede the effects of the present invention. For example, it may contain resins other than polyphenylene ether, polyphenylene ethers other than those mentioned above, inorganic fillers such as silica, and flame retardants such as phosphorus-containing compounds. Further, a crosslinked curing agent other than the above-mentioned epoxy-reactive crosslinked curing agent (for example, triallyl isocyanurate such as TAIC or triallyl cyanurate) may be included.

Note that such a curable composition can be obtained by appropriately mixing each raw material.

<<Cured product>>
The cured product can be obtained by curing the above-mentioned curable composition.

The method for obtaining a cured product from a curable composition is not particularly limited, and can be changed as appropriate depending on the composition of the curable composition. As an example, after carrying out the step of coating the curable composition on the substrate as described above (e.g., coating with an applicator, etc.), a drying step of drying the curable composition is carried out as necessary. Then, a thermosetting step may be carried out in which the polyphenylene ether is thermally crosslinked by heating (for example, heating using an inert gas oven, hot plate, vacuum oven, vacuum press machine, etc.). Note that the conditions for implementing each step (for example, coating thickness, drying temperature and time, heating temperature and time, etc.) may be changed as appropriate depending on the composition, use, etc. of the curable composition.

<<Dry film, prepreg>>
The dry film or prepreg of the present invention is obtained by applying the above-mentioned curable composition to a base material.

Here, examples of the base material include metal foil such as copper foil, films such as polyimide film, polyester film, and polyethylene naphthalate (PEN) film, glass cloth, and fibers such as aramid fiber.

The dry film can be obtained, for example, by applying a curable composition onto a polyethylene terephthalate film, drying it, and laminating a polypropylene film as necessary.

The prepreg can be obtained, for example, by impregnating glass cloth with a curable composition and drying it.

<<Laminated board>>
In the present invention, a laminate can be produced using the above prepreg.

To explain in detail, one or more prepregs of the present invention are stacked, metal foils such as copper foils are stacked on both sides or one side of the top and bottom, and the laminate is heated and press-molded to form an integrated laminate. It is possible to produce a laminate having metal foil on both sides or metal foil on one side.

<<Electronic parts>>
Since such a cured product has excellent dielectric properties and heat resistance, it can be used for electronic parts and the like.

Electronic components having a cured product are not particularly limited, but preferably include millimeter wave radars for high-capacity high-speed communications represented by 5th generation communication systems (5G) and automobile ADAS (advanced driving systems). .

Next, the present invention will be explained in detail with reference to Examples and Comparative Examples, but the present invention is not limited thereto.

<<Side chain epoxidized PPE>>
Side chain epoxidized PPE was prepared as follows.

<Side chain epoxidized PPE-1>
(Synthesis of PPE-1)
In a 3L two-necked eggplant flask, 5.3g of di-μ-hydroxo-bis[(N,N,N',N'-tetramethylethylenediamine)copper(II)]chloride (Cu/TMEDA) and tetramethyl 5.7 mL of ethylenediamine (TMEDA) was added and sufficiently dissolved, and oxygen was supplied at 10 ml/min. 10.0 g of о-cresol, 13.7 g of 2-allyl-6-methylphenol, and 90.3 g of 2,6-dimethylphenol were dissolved in 1.5 L of toluene, added dropwise to a flask, and stirred at a rotation speed of 600 rpm. The reaction was carried out at 40°C for 6 hours. After the reaction was completed, it was reprecipitated with a mixture of 20 L of methanol and 22 mL of concentrated hydrochloric acid, filtered out, and dried at 80° C. for 24 hours to obtain PPE-1.

(Side chain epoxidation)
50 g of PPE-1 and 400 mL of tetrahydrofuran were added to a two-necked eggplant flask equipped with a dropping funnel, and stirred in an ice bath. A solution of 31 g of metachloroperbenzoic acid (mCPBA) dissolved in 1.6 L of tetrahydrofuran was added dropwise over 30 minutes, and the mixture was stirred at room temperature for 24 hours. The reaction solution was reprecipitated in methanol, taken out by filtration, and dried at 80° C. for 24 hours to obtain side chain epoxidized PPE-1.

The obtained solid (side chain epoxidized PPE-1) was analyzed by 1H NMR (400 MHz, CDCl3, TMS) to detect peaks derived from epoxy groups around 2 to 3.5 ppm and peaks derived from allyl groups around 5 to 6.5 ppm. From the disappearance of , it was confirmed that 50% of the allyl group in the side chain was epoxidized.

As shown below, by changing the type of raw material phenols and their blending ratio, but without changing the total blending amount of phenols, side chain epoxidized PPE-2 to PPE-4 was obtained. Table 1 shows the phenols used in the synthesis of PPE-1 to PPE-4 and their blending ratios (molar ratios). Side chain epoxidation Similar to PPE-1, it was confirmed that 50% of the allyl groups in the side chains were epoxidized in all cases.

<Side chain epoxidized PPE-2>
Side chain epoxidized PPE (PPE-2) was obtained in the same manner as the synthesis method of side chain epoxidized PPE-1, except that the blending ratio of the raw material phenols was changed and 93 g of mCPBA was used.

<Side chain epoxidized PPE-3>
Side chain epoxidized PPE (PPE-3) was obtained in the same manner as the synthesis method of side chain epoxidized PPE-1, except that the blending ratio of the raw material phenols was changed and 155 g of mCPBA was used.

<Side chain epoxidized PPE-4>
Side chain epoxidized PPE (PPE-4) was obtained using the same method as the synthesis method of side chain epoxidized PPE-1, except that the type of raw material phenols and their blending ratio were changed and chloroform was used instead of tetrahydrofuran. .

The slope of the conformational plot for each PPE was determined according to the method described above.

<<Non-side chain epoxidized PPE>>
PPE different from side chain epoxidized PPE (non-side chain epoxidized PPE) was prepared as follows. The summary is shown in Table 2.

<PPE-5>
In a 3 L two-necked eggplant flask, 5.3 g of di-μ-hydroxo-bis[(N,N,N',N'-tetramethylethylenediamine)copper(II)] chloride (Cu/TMEDA) and tetra 5.7 mL of methyl ethylene diamine (TMEDA) was added and sufficiently dissolved, and oxygen was supplied at 10 mL/min. 7.00 g of о-cresol, 13.7 g of 2-allyl-6-methylphenol, and 93.9 g of 2,6-dimethylphenol were dissolved in 1.5 L of toluene, added dropwise to a flask, and stirred at a rotation speed of 600 rpm. The reaction was carried out at 40°C for 6 hours. After the reaction was completed, it was reprecipitated with a mixture of 20 L of methanol and 22 mL of concentrated hydrochloric acid, filtered out, and dried at 80° C. for 24 hours to obtain PPE-5.

<PPE-6>
In a 3L two-necked eggplant flask, 5.3g of di-μ-hydroxo-bis[(N,N,N',N'-tetramethylethylenediamine)copper(II)]chloride (Cu/TMEDA) and tetramethyl 70 mL of ethylenediamine (TMEDA) was added and sufficiently dissolved, and oxygen was supplied at 10 ml/min. 13.7 g of 2-allyl-6-methylphenol and 93.9 g of 2,6-dimethylphenol were dissolved in 0.5 L of toluene, added dropwise to a flask, and reacted at 40° C. for 6 hours while stirring at a rotation speed of 600 rpm. Ta. After the reaction was completed, it was reprecipitated with a mixture of 20 L of methanol and 22 mL of concentrated hydrochloric acid, filtered out, and dried at 80° C. for 24 hours to obtain PPE-6.

The slope of the conformation plot for each PPE was determined.

<<Preparation of composition varnish>>
A varnish was prepared by adding and mixing each component with cyclohexanone so that the solid content concentration was 50% by mass at the mass mixing ratio shown in the table below. Since the comparative example is not soluble in cyclohexanone, chloroform was used instead.

<Low temperature curability>
Each composition was applied to the shine side of a 18 μm thick copper foil using an applicator so that the thickness of the cured product was 50 μm. Next, it was dried at 90° C. for 30 minutes in a hot air circulation drying oven. Thereafter, it was heated in a hot air circulation drying oven at 180° C. for 60 minutes to obtain a cured film.

A rubbing test was performed on each cured film using a cloth impregnated with toluene, and those in which the cured film did not dissolve were judged to be cured.
Specifically, after 10 rubbing tests, the cured film does not dissolve, "◎", after 5 rubbing tests, the cured film does not dissolve, "○", after 5 rubbing tests, the cured film Those in which the was dissolved were evaluated as "x".

<Environmental response>
As an evaluation of environmental friendliness, the composition using cyclohexanone as a solvent was evaluated as "○", and the composition using chloroform as a solvent was evaluated as "x".

<Preparation of cured product (cured film)>
Each composition was applied to the shine side of a 18 μm thick copper foil using an applicator so that the thickness of the cured product was 50 μm. Next, it was dried at 90° C. for 30 minutes in a hot air circulation drying oven. Thereafter, it was heated at 180° C. for 60 minutes in a hot air circulation drying oven. After curing the composition, the copper foil was removed by etching to obtain a cured film.

<Dielectric properties>
The dielectric properties, dielectric constant Dk and dielectric loss tangent Df, were measured according to the following methods.
The cured film was cut to a length of 80 mm, width of 45 mm, and thickness of 50 μm, and this was used as a test piece for measurement using the SPDR (Split Post Dielectric Resonator) resonator method. The measuring equipment used was a vector network analyzer E5071C manufactured by Keysight Technologies LLC, an SPDR resonator, and a calculation program manufactured by QWED. The conditions were a frequency of 10 GHz and a measurement temperature of 25°C.

As a dielectric property evaluation, those with Dk less than 2.8 and Df less than 0.005 are marked "◎", and those with Dk less than 3.0 and Df less than 0.01 are marked "○". Items that were not applicable were evaluated as "×".

<Tensile properties>
The cured film was cut out to a length of 8 cm, width of 0.5 cm, and thickness of 50 μm, and the tensile elongation at break was measured under the following conditions.
[Measurement condition]
Testing machine: Tensile testing machine EZ-SX (manufactured by Shimadzu Corporation)
Distance between chucks: 50mm
Test speed: 1mm/min
Elongation calculation: (tensile movement amount/distance between chucks) x 100

(Evaluation criteria)
Those with a tensile elongation at break of 1.5% or more were evaluated as "◎", those with a tensile elongation at break of 1.0% or more and less than 1.5% were evaluated as "○", and those with a tensile elongation at break of less than 1.0% were evaluated as "x".

Claims (6)

A curable composition comprising a side chain epoxidized polyphenylene ether and another polyphenylene ether different from the side chain epoxidized polyphenylene ether,
The side chain epoxidized polyphenylene ether is a phenol (A) that satisfies at least the following conditions 1 and 2, or a phenol (B) that satisfies at least the following condition 1 and does not satisfy the following condition 2, and the following condition 1. A polyphenylene ether made of raw material phenols containing a mixture of phenols (C) that does not satisfy the following conditions 2 and satisfies condition 2 below, in which part or all of the side chain unsaturated carbon bonds are epoxidized,
and/or The other polyphenylene ether is a phenol (A) that satisfies at least both Condition 1 and Condition 2 below, or a phenol (B) that satisfies at least Condition 1 below but does not satisfy Condition 2 below, and the following conditions. It is made of raw material phenols containing a mixture of phenols (C) that do not satisfy condition 1 but satisfy condition 2 below,
The number average molecular weight of the side chain epoxidized polyphenylene ether is 1,000 to 20,000,
The epoxidation rate of the side chain epoxidized polyphenylene ether is 1% or more,
A curable composition in which the proportion of phenols satisfying the following condition 1 is 1 to 50 mol% and the proportion of phenols satisfying the following condition 2 to the total of raw material phenols of the side chain epoxidized polyphenylene ether is 1 to 99 mol%. thing.
(Condition 1)
Has hydrogen atoms at the ortho and para positions (condition 2)
Has a hydrogen atom in the para position and a hydrocarbon group containing an unsaturated carbon bond The curable composition according to claim 1, further comprising an epoxy group-reactive crosslinked curing agent. A dry film or prepreg obtained by applying the curable composition according to claim 1 or 2 to a substrate. A cured product obtained by curing the curable composition according to claim 1 or 2. A laminate comprising the cured product according to claim 4. An electronic component comprising the cured product according to claim 4.