JP2024092569A - Phenoxy resin, resin composition, cured product, laminate for electric/electronic circuits, and method for producing phenoxy resin - Google Patents

Abstract

[Problem] To provide a phenoxy resin with low viscosity and excellent dielectric properties, and to provide a cured product with excellent heat resistance and dielectric properties by curing a resin composition containing the same. [Solution] To provide a phenoxy resin represented by the following general formula (1) and having a weight average molecular weight of 10,000 to 200,000. [Chemical formula 1] TIFF2024092569000033.tif25167 In the formula, X is a divalent group containing an alkenyl-containing aromatic group. Y is independently a hydrogen atom, an acyl group having 2 to 20 carbon atoms, or a glycidyl group. Z is an acyl group having 2 to 20 carbon atoms or a hydrogen atom, and 5 mol % or more of Z is an acyl group. n is the number of repetitions, the average value of which is 15 or more and 500 or less. [Selected Figure] Figure 1

Description

The present invention relates to a phenoxy resin that has low viscosity, excellent solvent solubility, and excellent dielectric properties. It also relates to a resin composition containing the phenoxy resin and a curing agent, a cured product thereof that has excellent heat resistance and dielectric properties, and a laminate for electric and electronic circuits made of the resin composition.

Epoxy resins are widely used in fields such as paints, civil engineering, adhesives, and electrical materials because of their excellent heat resistance, adhesive properties, chemical resistance, water resistance, mechanical strength, and electrical properties. They can also be made into film by increasing their molecular weight in various ways. Such highly molecular epoxy resins are called phenoxy resins. In particular, bisphenol A-type phenoxy resins are used mainly as base resins for paint varnishes and for film molding, and are added to epoxy resin varnishes to adjust the flowability and improve the toughness and adhesive properties of the cured product. In addition, those that have phosphorus or bromine atoms in the skeleton are used as flame retardants blended into epoxy resin compositions and thermoplastic resins.

Phenoxy resins used as electrical materials in laminates for electric and electronic circuits are required to have solvent solubility and dielectric properties in addition to heat resistance, etc. In recent years, information devices have rapidly become smaller and more powerful, and as a result, materials used in the fields of semiconductors and electronic components are required to have higher performance than ever before, especially low dielectric properties to accommodate thinner and more highly functional substrates.
In response to such demands, a method has been proposed in which the hydroxyl groups present in the side chains of the phenoxy resin are converted into esters using acetyl or benzoyl groups to improve the dielectric properties.

For example, Patent Document 1 proposes an epoxy resin obtained by reacting a bifunctional epoxy resin with a diester compound. However, the epoxy resin obtained by this method has drawbacks such as high viscosity and poor processability and compatibility during production.
Patent Document 2 proposes an epoxy resin obtained by reacting a difunctional epoxy resin with a divalent hydroxyl group-containing compound. However, the obtained epoxy resin has a drawback in that it has poor dielectric properties.

JP 2016-89165 A JP 2019-35087 A

The objective of the present invention is to provide a phenoxy resin with low viscosity and excellent dielectric properties. In addition, the objective of the present invention is to provide a cured product with excellent heat resistance and dielectric properties by curing a resin composition containing the phenoxy resin.

In order to solve the above problems, the inventors conducted extensive research into phenoxy resins and discovered that phenoxy resins containing alkenyl groups have low viscosity and excellent dielectric properties, and further discovered that the cured product obtained by curing a resin composition containing this has excellent heat resistance and dielectric properties, thus completing the present invention.

式中、Ｘはアルケニル含有芳香族基を含む２価の基である。Ｙは独立に、水素原子、炭素数２～２０のアシル基、又はグリシジル基である。Ｚは炭素数２～２０のアシル基又は水素原子であり、５モル％以上はアシル基である。ｎは繰り返し数であり、その平均値は１５以上５００以下である。 That is, the present invention relates to a phenoxy resin represented by the following formula (1) and having a weight average molecular weight of 10,000 to 200,000.

In the formula, X is a divalent group containing an alkenyl-containing aromatic group. Y is independently a hydrogen atom, an acyl group having 2 to 20 carbon atoms, or a glycidyl group. Z is an acyl group having 2 to 20 carbon atoms or a hydrogen atom, and 5 mol % or more of Z is an acyl group. n is the number of repetitions, and the average value is 15 or more and 500 or less.

式中、Ａは直接結合、炭素数１～１３の２価の炭化水素基、－Ｓ－、－ＳＯ_２－、－ＳＯ－、－Ｓ－Ｓ－、－Ｏ－、－ＣＯ－、－ＣＯＯ－、及び－Ｃ（ＣＦ_３）_２－から選ばれる基である。Ｒ^１は炭素数３～１２のアルケニル基であり、Ｒ^２は独立に、水素原子、炭素数１～１２のアルキル基、炭素数１～１２のアルコキシ基、炭素数６～１２のアリール基、又は炭素数３～１２のアルケニル基である。ｋは０又は１である。 In the phenoxy resin of the present invention, the alkenyl-containing aromatic group is preferably an alkenyl-containing aromatic group represented by the following formula (2) and/or formula (3).

In the formula, A is a group selected from a direct bond, a divalent hydrocarbon group having 1 to 13 carbon atoms, -S-, -SO ₂ -, -SO-, -S-S-, -O-, -CO-, -COO-, and -C(CF ₃ ) ₂ -. R ¹ is an alkenyl group having 3 to 12 carbon atoms, and R ² is independently a hydrogen atom, an alkyl group having 1 to 12 carbon atoms, an alkoxy group having 1 to 12 carbon atoms, an aryl group having 6 to 12 carbon atoms, or an alkenyl group having 3 to 12 carbon atoms. k is 0 or 1.

The alkenyl equivalent of the above phenoxy resin is preferably 100 to 1000 g/eq.

The present invention also relates to a resin composition that contains the above-mentioned phenoxy resin and either a radical polymerization initiator or a curing agent, or both.

In the above resin composition, it is preferable that the radical polymerization initiator or curing agent is 0.1 to 30 parts by mass per 100 parts by mass of the phenoxy resin. When a thermosetting resin is used in combination, it is preferable that the mass ratio of the phenoxy resin to the thermosetting resin is 99/1 to 1/99.

The present invention also relates to a cured product obtained by curing the above-mentioned resin composition, and to a laminate for electrical/electronic circuits made using the above-mentioned resin composition.

式中、Ｘ^１は、式（４）と式（５）の少なくとも一方において、アルケニル含有芳香族基を含む。Ｇはグリシジル基である。ｍは繰り返し数であり、その平均値は０以上６以下である。Ｚ^１は炭素数２～２０の炭化水素基を有するアシル基又は水素原子であり、５モル％以上はアシル基である。 The present invention also provides a method for producing the above-mentioned phenoxy resin, which comprises reacting a bifunctional epoxy resin represented by the following formula (4) with a compound represented by the following formula (5).

In the formula, ^X1 contains an alkenyl-containing aromatic group in at least one of formula (4) and formula (5). G is a glycidyl group. m is the number of repetitions, the average value of which is 0 to 6. ^Z1 is an acyl group having a hydrocarbon group with 2 to 20 carbon atoms or a hydrogen atom, and 5 mol % or more of Z1 is an acyl group.

式中、Ｘ、ｎは式（１）におけるＸ、ｎと同義である。Ｚ^２は炭素数２～２０のアシル基である。 In the method for producing the phenoxy resin of the present invention, the alkenyl-containing aromatic group contained in ^X1 in formula (4) or formula (5) is preferably an alkenyl-containing aromatic group represented by formula (2) and/or formula (3).
Further, the present invention provides a method for producing the above-mentioned phenoxy resin, characterized in that 0.05 to 2.0 moles of an acyl group of an acylating agent are reacted with 1 mole of an alcoholic hydroxyl group of the phenoxy resin represented by the following formula (6). The acylating agent is preferably an acid anhydride represented by the following formula (7).

In the formula, X and n are defined as the same as X and n in formula (1), ^{and Z2} is an acyl group having 2 to 20 carbon atoms.

According to the present invention, it is possible to provide a phenoxy resin that has low viscosity, solvent solubility, and excellent dielectric properties. In addition, a resin composition using this phenoxy resin can provide a cured product that has excellent heat resistance, dielectric properties, and folding resistance.

1 shows a GPC chart of the phenoxy resin obtained in Example 1. 1 shows an IR chart of the phenoxy resin obtained in Example 1.

The present invention will be described in detail below.
The phenoxy resin of the present invention is a phenoxy resin having a weight average molecular weight (Mw) of 10,000 to 200,000, represented by the following formula (1), which contains an alkenyl-containing aromatic group and further has a structure in which some or all of the hydrogen atoms in the hydroxyl groups are substituted with acyl groups (Z).

Here, if the Mw is less than 10,000, the film-forming properties and mechanical properties (particularly folding resistance) may decrease, which is not preferred. If the Mw is more than 200,000, the compatibility may decrease, and the resin may become difficult to handle, which is not preferred. The Mw is preferably 15,000 to 150,000, more preferably 20,000 to 100,000, and even more preferably 20,000 to 50,000. The Mw of the phenoxy resin can be measured by the gel permeation chromatography method (GPC method) described in the examples.

The phenoxy resin of the present invention has a structure in which the hydrogen atoms in the hydroxyl groups are replaced with acyl groups, which gives it low polarity and excellent dielectric properties. It also has good solvent solubility.

Furthermore, by introducing an alkenyl group into the aromatic ring, the phenoxy resin of the present invention has a large free volume, a low viscosity, and a low polarity, which further improves the dielectric properties.
Here, the alkenyl equivalent (g/eq.) is preferably 100 to 1000, more preferably 150 to 800, and even more preferably 200 to 500. Within this range, the effect of lowering the viscosity and improving the dielectric properties can be obtained, and furthermore, it is possible for the alkenyl equivalent to be involved in the curing reaction and to be incorporated into the crosslinked structure. The measurement conditions for the alkenyl equivalent are in accordance with the conditions described in the Examples.

In formula (1),
X is a divalent group and includes an alkenyl-containing aromatic group (Xa) and other divalent groups (Xb).
The alkenyl-containing aromatic group (Xa) is preferably 10 mol % or more, more preferably 25 mol % or more, and even more preferably 45 mol % or more, based on the total number of moles of X. Outside this range, the viscosity and dielectric properties may deteriorate.
The alkenyl-containing aromatic group (Xa) is preferably represented by the following formula (2) or (3).

In formula (2),
A is a group selected from a direct bond, a divalent hydrocarbon group having 1 to 13 carbon atoms, -S-, -SO ₂ -, -SO-, -S-S-, -O-, -CO-, -COO-, and -C(CF ₃ ) ₂ -.

The divalent hydrocarbon group having 1 to 13 carbon atoms is preferably an alkylene group having 1 to 12 carbon atoms or an arylene group having 6 to 13 carbon atoms, and may be linear, branched, or cyclic, such as, for example, -CH ₂ -, -C(CH ₃ ) ₂ -, -CH(CH ₃ )-, -CHPh-, -C(CH ₃ )Ph-, -C(CH ₃ )(C ₂ H ₅ )-, -C(Ph) ₂ -, -C ₂ H ₄ -, -C ₃ H ₆ -, -C ₄ H ₈ , 1,1-cyclopentylene group, 1,1-cyclohexylene group, 1,1-cycloheptylene group, methyl-1,1-cyclohexylene group, 1,1-cyclononylene group, 1,1-cyclooctylene group, 3,3,5-trimethyl-1,1-cyclohexylene group, 1,1-cyclodecylene group, 1,1-cyclododecylene group, 1,2-cyclopentylene group, 1,2-cyclohexylene group, 1,3-cyclopentylene group, 1,3-cyclohexylene group, 1,4-cyclohexylene group, 1,2-phenylene group, 1,3-phenylene group, 1,4-phenylene group, 1,2-xylylene group, 1,4-xylylene group, tetrahydrodicyclopentadienylene group, tetrahydrotricyclopentadienylene group, 1,1-fluorenediyl group and the like. Ph represents a phenyl group (-C ₆ H ₅ ), and so long as the total number of carbon atoms is 13 or less, the phenyl group may have a substituent.

In formula (2) and formula (3),
R ¹ is an alkenyl group having 3 to 12 carbon atoms;
^R2 is independently a hydrogen atom, an alkyl group having 1 to 12 carbon atoms, an alkoxy group having 1 to 12 carbon atoms, an aryl group having 6 to 12 carbon atoms, or an alkenyl group having 3 to 12 carbon atoms.
k is 0 or 1.

The alkenyl group having 3 to 12 carbon atoms may be linear, branched, or cyclic, and examples thereof include, but are not limited to, 2-propenyl, 2-butenyl, 3-butenyl, 1,3-butadienyl, cyclohexenyl, cyclohexadienyl, cinnamyl, and naphthylvinyl groups.

The alkyl group having 1 to 12 carbon atoms may be linear, branched, or cyclic, and examples thereof include, but are not limited to, methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, t-butyl, n-pentyl, isopentyl, neopentyl, t-pentyl, cyclopentyl, n-hexyl, isohexyl, cyclohexyl, n-heptyl, cycloheptyl, methylcyclohexyl, n-octyl, cyclooctyl, n-nonyl, 3,3,5-trimethylcyclohexyl, n-decyl, cyclodecyl, n-undecyl, n-dodecyl, cyclododecyl, benzyl, methylbenzyl, dimethylbenzyl, trimethylbenzyl, naphthylmethyl, phenethyl, and 2-phenylisopropyl.

The alkoxy group having 1 to 12 carbon atoms may be linear, branched, or cyclic, and examples thereof include methoxy, ethoxy, n-propoxy, isopropoxy, n-butoxy, sec-butoxy, t-butoxy, n-pentoxy, isopentoxy, neopentoxy, t-pentoxy, cyclopentoxy, n-hexyloxy, isohexyloxy, cyclohexyloxy, n-heptoxy, cycloheptoxy, methylcyclohexyloxy, and methylcyclohexyloxy. Examples of the alkyl groups include, but are not limited to, oxy group, n-octyloxy group, cyclooctyloxy group, n-nonyloxy group, 3,3,5-trimethylcyclohexyloxy group, n-decyloxy group, cyclodecyloxy group, n-undecyloxy group, n-dodecyloxy group, cyclododecyloxy group, benzyloxy group, methylbenzyloxy group, dimethylbenzyloxy group, trimethylbenzyloxy group, naphthylmethoxy group, phenethyloxy group, and 2-phenylisopropoxy group.

Examples of aryl groups having 6 to 12 carbon atoms include, but are not limited to, phenyl, o-tolyl, m-tolyl, p-tolyl, ethylphenyl, styryl, xylyl, n-propylphenyl, isopropylphenyl, mesityl, ethynylphenyl, naphthyl, and vinylnaphthyl groups.

Among the above, R ¹ is preferably an alkenyl group having 3 to 5 carbon atoms, more preferably an alkenyl group having 3 carbon atoms, and particularly preferably a 2-propenyl group. This is because a large substituent may cause a decrease in heat resistance.

Among the above, ^R2 is preferably a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, or an alkenyl group having 3 to 5 carbon atoms, more preferably a hydrogen atom or an alkenyl group having 3 carbon atoms, and even more preferably at least one alkenyl group having 3 carbon atoms. As the alkenyl group having 3 carbon atoms, a 2-propenyl group is particularly preferable. This is because a large substituent may reduce heat resistance. In addition, when there are two or more alkenyl groups including ^R1 , the viscosity is further reduced and the dielectric properties are further improved, and the heat resistance of the resin composition is further improved.

In the phenoxy resin of the present invention, in the general formula (1), X may be a divalent group (Xb group) having no alkenyl group other than Xa group. The content of Xb group in X is 90 mol% or less, preferably 75 mol% or less, more preferably 55 mol% or less.
The Xb group is, for example, a divalent hydrocarbon group or a hydrocarbon group which may have in the hydrocarbon chain a group such as -O-, -CO-, -S-, -COO-, -SO-, -SO ₂ -, -S-S-, -C(CF ₃ ) ₂ -, etc. For example, in the divalent groups represented by formulas (2) and (3), R ¹ and R ² are independently a hydrogen atom, an alkyl group having 1 to 12 carbon atoms, an alkoxy group having 1 to 12 carbon atoms, or an aryl group having 6 to 12 carbon atoms.

Examples of divalent groups include an aromatic skeleton (Xb1) that represents the skeleton remaining after removing two hydroxyl groups from an aromatic diol compound, an aliphatic skeleton (Xb2) that represents the skeleton remaining after removing two hydroxyl groups from an aliphatic diol compound, an alicyclic skeleton (Xb3) that represents the skeleton remaining after removing two hydroxyl groups from an alicyclic diol compound, an aromatic skeleton (Xb1) that represents the skeleton remaining after removing two acyloxy groups from an aromatic diester compound, an aliphatic skeleton (Xb2) that represents the skeleton remaining after removing two acyloxy groups from an aliphatic diester compound, and an alicyclic skeleton (Xb4) that represents the skeleton remaining after removing two acyloxy groups from an alicyclic diester compound. alicyclic skeleton (Xb3) representing the skeleton of the cyclic group; aromatic skeleton (Xb1) representing the skeleton remaining after removing two glycidyloxy groups from a diepoxy compound made from an aromatic diol compound; aliphatic skeleton (Xb2) representing the skeleton remaining after removing two glycidyloxy groups from a diepoxy compound made from an aliphatic diol compound; alicyclic skeleton (Xb3) representing the skeleton remaining after removing two glycidyloxy groups from a diepoxy compound made from an alicyclic diol compound; and alicyclic skeleton (Xb4) representing the skeleton remaining after removing two oxygen atoms from a cycloalkane diepoxy compound.

Examples of the aromatic diol compound, aromatic diester compound, or aromatic diepoxy compound that constitutes the aromatic skeleton (Xb1) include bisphenol-type compounds that may be unsubstituted or have an alkyl group having 1 to 10 carbon atoms as a substituent, such as bisphenol A, bisphenol acetophenone, bisphenol AF, bisphenol AD, bisphenol B, bisphenol BP, bisphenol C, bisphenol E, bisphenol F, bisphenol G, bisphenol M, bisphenol S, bisphenol P, bisphenol PH, bisphenol trimethylcyclohexane, bisphenol cyclohexane, dihydroxybenzophenone, dihydroxydiphenyl ether, phenolphthalein, phenolphthalein anilide, and fluorescein, biphenyl-type compounds such as dihydroxybiphenyls that may be unsubstituted or have an alkyl group having 1 to 10 carbon atoms as a substituent, and bisphenol fluorene-type compounds that may be unsubstituted or have an alkyl group having 1 to 10 carbon atoms as a substituent. fluorene-type fluorenes such as naphtholfluorenes and bisnaphtholfluorenes, 10-(2,5-dihydroxyphenyl)-9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO-HQ), 10-(2,7-dihydroxynaphthyl)-9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO-NQ), 10-(1,4-dihydroxy-2-naphthyl)-10H-9-oxa-10-phosphaphenanthrene-10-oxide, diphenylphosphine Examples of the aromatic diol compounds include phosphorus-containing phenols which may have an unsubstituted or C1-C10 alkyl, aryl or aralkyl group as a substituent, such as diphenylhydroquinone, diphenylphosphinyl-1,4-dioxynaphthalene, 1,4-cyclooctylenephosphinyl-1,4-phenyldiol, 1,5-cyclooctylenephosphinyl-1,4-phenyldiol, diester compounds obtained by acylation of these aromatic diol compounds, and diepoxy compounds using these aromatic diol compounds as a raw material.
Preferred are bisphenolacetophenone, bisphenol AF, bisphenoltrimethylcyclohexane, bisphenolcyclohexane, dihydroxybenzophenone, dihydroxydiphenyl ether, phenolphthalein, phenolphthalein anilide and fluorescein, unsubstituted or C1-10 alkyl group substituted dihydroxybiphenyl, unsubstituted or C1-10 alkyl group substituted bisphenolfluorene, unsubstituted or C1-10 alkyl group substituted bisnaphtholfluorene, unsubstituted or C1-10 alkyl group substituted DOPO-HQ, DOPO-NQ, unsubstituted or C1-10 alkyl, aryl or aralkyl group substituted DOPO-HQ, diester compounds obtained by acylation of preferred aromatic diol compounds, and diepoxy compounds using preferred aromatic diol compounds as raw materials. Particularly preferred are bisphenolacetophenone, bisphenol AF, bisphenoltrimethylcyclohexane, bisphenolcyclohexane, dihydroxybenzophenone, dihydroxydiphenyl ether, phenolphthalein, dihydroxybiphenyl, bisphenolfluorene, biscresofluorene, bisnaphtholfluorene, DOPO-HQ, DOPO-NQ, diester compounds obtained by acylation of particularly preferred aromatic diol compounds, and diepoxy compounds obtained from particularly preferred aromatic diol compounds.

Even if the aromatic skeleton (Xb1) has an alkenyl group as a substituent other than the group represented by formula (2) or (3), it is an alkenyl-containing aromatic skeleton (Xa). In this case, the alkenyl group is preferably the same as ^R1 .

Examples of the aliphatic diol compound, aliphatic diester compound, or aliphatic diepoxy compound that serves as the aliphatic skeleton (Xb2) include alkylene glycol skeletons such as ethylene glycol, propylene glycol, and butylene glycol, diester compounds obtained by acylation of these aliphatic diol compounds, and diepoxy compounds made from these aliphatic diol compounds.

Examples of the alicyclic diol compound, alicyclic diester compound, or alicyclic diepoxy compound that serves as the alicyclic skeleton (Xb3) include hydrogenated bisphenol skeletons such as hydrogenated bisphenol A, hydrogenated bisphenol F, and hydrogenated bisphenol acetophenone, diester compounds obtained by acylation of these alicyclic diol compounds, and diepoxy compounds made from these alicyclic diol compounds.

Examples of cycloalkane diepoxy compounds that form the alicyclic skeleton (Xb4) include diepoxidized products of cyclohexylmethylcyclohexanecarboxylate, tetrahydroindene, and hydrogenated tricyclopentadiene. A diepoxidized product of cyclohexylmethylcyclohexanecarboxylate is preferred.

In formula (1),
Y is independently a hydrogen atom, an acyl group having 2 to 20 carbon atoms, or a glycidyl group. When Y is a hydrogen atom, a hydroxyl group is provided at the end, when Y is an acyl group, an ester group is provided at the end, and when Y is a glycidyl group, an epoxy group is provided at the end, so it is advisable to control the ratio according to the application.

In the acyl group (R-CO-), R is preferably an alkyl group having 1 to 12 carbon atoms, an aryl group having 6 to 12 carbon atoms, or an aralkyl group having 7 to 13 carbon atoms, and examples of such groups include those exemplified for R ^2. As the acyl group, an acyl group having 2 to 7 carbon atoms is more preferable, and an acetyl group, a propanoyl group, a butanoyl group, a benzoyl group, or a methylbenzoyl group is even more preferable, and an acetyl group or a benzoyl group is particularly preferable.

In formula (1), Z is an acyl group having 2 to 20 carbon atoms or a hydrogen atom. At least 5 mol % of Z is an acyl group, and the remainder is a hydrogen atom. At least 10 mol % of Z is an acyl group, preferably at least 20 mol %, more preferably at least 50 mol %, and even more preferably at least 70 mol %. The upper limit is preferably 100%, but substantially 95% is sufficient. The acyl group having a hydrocarbon group having 1 to 20 carbon atoms is the same as the exemplified acyl group for Y, and the preferred acyl groups are also the same.
When all Z's (100 mol%) are acyl groups, the phenoxy resin of the present invention does not contain secondary hydroxyl groups, and the dielectric properties and moisture resistance can be further improved. On the other hand, when finely adjusting the adhesion to metals, for example, by leaving a part of Z as a hydrogen atom, it is possible to intentionally allow a suitable amount of secondary hydroxyl groups to be present in the phenoxy resin of the present invention, within a range that does not significantly affect other physical properties including moisture resistance.

In formula (1), n is the number of repetitions, and its average value is in the range of 15 to 500. From the viewpoint of moldability and handleability, it is preferably 17 to 400, more preferably 20 to 300. The number n can be calculated from the number average molecular weight (Mn) obtained by the GPC method.

The epoxy equivalent of the phenoxy resin of the present invention is not particularly limited, but is preferably in the range of 2,000 to 50,000 g/eq. Within this range, the phenoxy resin of the present invention itself can participate in the curing reaction and be incorporated into the crosslinked structure.

The phenoxy resin of the present invention is one in which a part or all of the secondary hydroxyl groups are acylated, and can be obtained by various methods. For example, the following method is a preferred production method.
(A): A production method in which a bifunctional epoxy resin represented by formula (4) is reacted with a diester compound and/or a bifunctional phenol compound represented by formula (5). Hereinafter, this may be referred to as production method (A).
(B): A production method in which a phenoxy resin represented by formula (6) (sometimes referred to as phenoxy resin (a) to distinguish it from the phenoxy resin of the present invention) is reacted with an acid component (acylating agent) such as an organic acid anhydride, an organic acid halide, or an organic acid ester. Hereinafter, this method may be referred to as production method (B).
The phenoxy resins obtained by the production methods (A) and (B) are the phenoxy resins of the present invention and are represented by the same formula (1).

The production method (A) is a method in which a bifunctional epoxy resin represented by formula (4) is reacted with a compound represented by formula (5).
In formula (4), G is a glycyl group, m is the number of repetitions, the average value of which is 0 to 6.
In formula (5), 5 mol % or more of Z ¹ are acyl groups having a hydrocarbon group having 1 to 20 carbon atoms, and the remainder are hydrogen atoms. Here, the compound represented by formula (5) may be a mixture of two or more selected from a compound in which both Z ¹ are acyl groups, a compound in which one is an acyl group and the other is a hydrogen atom, and a compound in which both are hydrogen atoms. When both ^{Z 1} are acyl groups, the compound is a diester, and when both are hydrogen atoms, the compound is a diphenol. The compound represented by formula (5) is called a diester compound. The diester compound may be a compound in which both Z ¹ are acyl groups, or a mixture in which the main component (50% or more) is the compound.

X ¹ in formula (4) and formula (5) is selected to give X in formula (1). Therefore, X ¹ in formula (4) and formula (5) contains an alkenyl-containing aromatic group in either one, and formula (4) and formula (5) as a whole contain an alkenyl-containing aromatic group. For example, one of X ¹ in formula (4) or formula (5) can contain an alkenyl-containing aromatic group represented by formula (2), and the other can contain an alkenyl-containing aromatic group represented by formula (3), or only one of X ¹ in formula (4) or formula (5) can contain an alkenyl-containing aromatic group represented by formula (2) and formula (3), and the other can not contain an alkenyl-containing aromatic group.
The phenoxy resin of the present invention necessarily contains an alkenyl-containing aromatic group. As long as this requirement is satisfied, the alkenyl-containing aromatic group may be contained in either the bifunctional epoxy resin represented by formula (4) and/or the ester compound represented by formula (5), which are the raw materials, and the proportion thereof is not limited.
As long as X ¹ in formula (4) or formula (5) contains an alkenyl-containing aromatic group, another divalent group (Xb) may be present.

式（８）において、Ｘ^１は式（４）又は（５）のＸ^１と同様である。
エピハロヒドリンとしては、例えば、エピクロルヒドリンやエピブロモヒドリン等が挙げられる。
アルカリ金属化合物としては、例えば、水酸化ナトリウム、水酸化リチウム、水酸化カリウム等のアルカリ金属水酸化物や、炭酸ナトリウム、重炭酸ナトリウム、塩化ナトリウム、塩化リチウム、塩化カリウム等のアルカリ金属塩や、ナトリウムメトキシド、ナトリウムエトキシド等のアルカリ金属アルコキシドや、酢酸ナトリウム、ステアリン酸ナトリウム等の有機酸のアルカリ金属塩や、アルカリ金属フェノキシド、水素化ナトリウム、水素化リチウム等が挙げられる。 The bifunctional epoxy resin used in the production method (A) of the present invention is an epoxy resin represented by the above formula (4), and examples thereof include an epoxy resin obtained by reacting a bifunctional phenol compound represented by the following formula (8) with epihalohydrin in the presence of an alkali metal compound.

In formula (8), ^X1 is the same as ^X1 in formula (4) or (5).
Examples of epihalohydrin include epichlorohydrin and epibromohydrin.
Examples of alkali metal compounds include alkali metal hydroxides such as sodium hydroxide, lithium hydroxide, and potassium hydroxide; alkali metal salts such as sodium carbonate, sodium bicarbonate, sodium chloride, lithium chloride, and potassium chloride; alkali metal alkoxides such as sodium methoxide and sodium ethoxide; alkali metal salts of organic acids such as sodium acetate and sodium stearate; alkali metal phenoxides, sodium hydride, and lithium hydride.

In the reaction between a bifunctional phenolic compound and epihalohydrin to obtain the raw material epoxy resin, 0.80 to 1.20 moles, preferably 0.85 to 1.05 moles, of an alkali metal compound are used relative to the functional groups in the bifunctional phenolic compound. Less than this amount is not preferred as it leaves a large amount of residual hydrolyzable chlorine. The alkali metal compound is used in the form of an aqueous solution, alcohol solution, or solid.

In the epoxidation reaction, an excess amount of epihalohydrin is used relative to the bifunctional phenolic compound. Usually, 1.5 to 15 moles of epihalohydrin are used per mole of functional group in the bifunctional phenolic compound, but preferably 2 to 10 moles, and more preferably 5 to 8 moles. If the amount is more than this, the production efficiency decreases, and if it is less than this, the amount of high molecular weight epoxy resin produced increases, making it unsuitable as a raw material for phenoxy resin.

The epoxidation reaction is usually carried out at a temperature of 120°C or less. If the reaction temperature is high, the amount of so-called difficult to hydrolyze chlorine increases, making it difficult to achieve high purification. The temperature is preferably 100°C or less, and more preferably 85°C or less.

When a bifunctional phenol compound represented by formula (8) is reacted with epihalohydrin, m usually becomes greater than 0. In order to make m 0, an epoxy resin produced by a known method can be highly purified by distillation, crystallization, or the like, or a bifunctional phenol compound represented by formula (8) can be alkoxylated and then epoxidized by oxidizing a portion of the olefin moiety.

The diester compound used in the manufacturing method (A) of the present invention can be obtained, for example, by acylation of a bifunctional phenol compound represented by formula (8) with an acid anhydride of an organic acid, a halide of an organic acid, or a condensation reaction with an organic acid.

By using an epoxy resin in which m in formula (4) is 0 as the raw material, the phenoxy resin of the present invention does not contain secondary hydroxyl groups, and the dielectric properties and moisture resistance can be further improved. In addition, for example, when fine-tuning the adhesion to metals, by using an epoxy resin with an appropriate m number, it is possible to deliberately have an appropriate amount of secondary hydroxyl groups present in the phenoxy resin of the present invention, as long as it does not significantly affect other physical properties, including moisture resistance.

The bifunctional epoxy resin or diester compound used in the production method (A) preferably contains the chemical structures represented by formulas (2) and (3) in an amount of 1 to 100 mol % relative to the total number of moles of ^X1 in formulas (4) and (5). From the viewpoint of fully exhibiting the low viscosity and dielectric properties attributable to the chemical structures represented by formulas (2) and (3), the chemical structures represented by formulas (2) and (3) are more preferably 10 mol % or more, even more preferably 30 mol % or more, and particularly preferably 50 mol % or more.

The amount of the bifunctional epoxy resin and the diester compound used is preferably 0.8 to 1.0 equivalent of the ester group per equivalent of the epoxy group. This equivalent ratio is preferable because it facilitates the progress of high molecular weight in a state in which the epoxy group is present at the molecular end. It is also possible to replace a part of the diester compound with a bifunctional phenol compound represented by formula (8). As described above, this allows the physical properties to be finely adjusted by deliberately allowing an appropriate amount of secondary hydroxyl groups to be present in the phenoxy resin of the present invention.
In the production method (A), a polymerization reaction and an ester exchange reaction occur, increasing the Mw and producing a phenoxy resin, while a portion of the OH groups of the phenoxy resin is esterified.

In the manufacturing method (A), a catalyst may be used. The catalyst may be any compound that has catalytic ability to promote the reaction between the epoxy group and the ester group. Examples of the catalyst include tertiary amines, cyclic amines, imidazoles, organic phosphorus compounds, and quaternary ammonium salts. These catalysts may be used alone or in combination of two or more.

Examples of tertiary amines include, but are not limited to, triethylamine, tri-n-propylamine, tri-n-butylamine, triethanolamine, benzyldimethylamine, and 2,4,6-tris(dimethylaminomethyl)phenol.

Examples of cyclic amines include, but are not limited to, 1,4-diazabicyclo[2,2,2]octane (DABCO), 1,8-diazabicyclo[5,4,0]undecene-7 (DBU), 1,5-diazabicyclo[4,3,0]nonene-5 (DBN), N-methylmorpholine, pyridine, and N,N-dimethylaminopyridine (DMAP).

Examples of imidazoles include, but are not limited to, 2-methylimidazole, 2-ethyl-4-methylimidazole, 2-phenylimidazole, 2-phenyl-4-methylimidazole, 1-benzyl-2-methylimidazole, and 1-benzyl-2-phenylimidazole.

Examples of organic phosphorus compounds include phosphines such as tri-n-propylphosphine, tri-n-butylphosphine, diphenylmethylphosphine, triphenylphosphine, tris(p-tolyl)phosphine, tricyclohexylphosphine, tri(t-butyl)phosphine, tris(p-methoxyphenyl)phosphine, paramethylphosphine, 1,2-bis(dimethylphosphino)ethane, and 1,4-bis(diphenylphosphino)butane; tetramethylphosphonium bromide, tetramethylphosphonium iodide, tetramethylphosphonium hydroxide, tetrabutylphosphonium hydroxide, and tetramethylphosphonium iodide. Examples of phosphonium salts include, but are not limited to, trimethylcyclohexylphosphonium chloride, trimethylcyclohexylphosphonium bromide, trimethylbenzylphosphonium chloride, trimethylbenzylphosphonium bromide, tetraphenylphosphonium bromide, triphenylmethylphosphonium bromide, triphenylmethylphosphonium iodide, triphenylethylphosphonium chloride, triphenylethylphosphonium bromide, triphenylethylphosphonium iodide, triphenylbenzylphosphonium chloride, and triphenylbenzylphosphonium bromide.

Examples of quaternary ammonium salts include, but are not limited to, tetramethylammonium chloride, tetramethylammonium bromide, tetramethylammonium hydroxide, triethylmethylammonium chloride, tetraethylammonium chloride, tetraethylammonium bromide, tetraethylammonium iodide, tetrapropylammonium bromide, tetrapropylammonium hydroxide, tetrabutylammonium chloride, tetrabutylammonium bromide, tetrabutylammonium iodide, benzyltrimethylammonium chloride, benzyltrimethylammonium bromide, benzyltrimethylammonium hydroxide, benzyltributylammonium chloride, and phenyltrimethylammonium chloride.

Among the catalysts listed above, 4-(dimethylamino)pyridine, 1,4-diazabicyclo[2,2,2]octane, 1,8-diazabicyclo[5,4,0]undecene-7, 1,5-diazabicyclo[4,3,0]nonene-5, 2-ethyl-4-methylimidazole, tris(p-tolyl)phosphine, tricyclohexylphosphine, tri(t-butyl)phosphine, and tris(p-methoxyphenyl)phosphine are preferred, with 4-(dimethylamino)pyridine, 1,8-diazabicyclo[5,4,0]undecene-7, 1,5-diazabicyclo[4,3,0]nonene-5, and 2-ethyl-4-methylimidazole being particularly preferred.

The amount of catalyst used is usually 0.001 to 1 mass% of the reaction solids, but when these compounds are used as catalysts, the catalysts remain as residues in the resulting phenoxy resin, which may deteriorate the insulating properties of the printed wiring board or shorten the pot life of the composition, so the nitrogen content in the phenoxy resin is preferably 0.5 mass% or less, more preferably 0.3 mass% or less. The phosphorus content in the phenoxy resin is preferably 0.5 mass% or less, more preferably 0.3 mass%.

In the manufacturing method (A), a reaction solvent may be used. Any solvent that dissolves the phenoxy resin may be used. Examples of the solvent include aromatic solvents, ketone solvents, amide solvents, glycol ether solvents, and ester solvents. These solvents may be used alone or in combination of two or more.

Examples of aromatic solvents include benzene, toluene, and xylene.

Examples of ketone solvents include acetone, methyl ethyl ketone (MEK), methyl isobutyl ketone, 2-heptanone, 4-heptanone, 2-octanone, cyclohexanone, acetylacetone, dioxane, diisobutyl ketone, isophorone, methylcyclohexanone, and acetophenone.

Examples of amide solvents include formamide, N-methylformamide, N,N-dimethylformamide (DMF), acetamide, N-methylacetamide, N,N-dimethylacetamide, 2-pyrrolidone, and N-methylpyrrolidone.

Examples of glycol ether solvents include ethylene glycol monoalkyl ethers such as ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, and ethylene glycol mono-n-butyl ether; diethylene glycol monoalkyl ethers such as diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, and diethylene glycol mono-n-butyl ether; propylene glycol monoalkyl ethers such as propylene glycol monomethyl ether, propylene glycol monoethyl ether, and propylene glycol mono-n-butyl ether; ethylene glycol dialkyl ethers such as ethylene glycol dimethyl ether, ethylene glycol diethyl ether, and ethylene glycol dibutyl ether; polyethylene glycol dialkyl ethers such as diethylene glycol dimethyl ether, diethylene glycol diethyl ether, diethylene glycol dibutyl ether, triethylene glycol dimethyl ether, triethylene glycol diethyl ether, and triethylene glycol dibutyl ether; propylene glycol dimethyl ether, propylene glycol diethyl ether, and propylene glycol dibutyl ether; Examples of the glycol dialkyl ethers include polypropylene glycol dialkyl ethers such as dipropylene glycol dimethyl ether, dipropylene glycol diethyl ether, dipropylene glycol dibutyl ether, tripropylene glycol dimethyl ether, tripropylene glycol diethyl ether, and tripropylene glycol dibutyl ether; ethylene glycol monoalkyl ether acetates such as ethylene glycol monoethyl ether acetate, ethylene glycol monoethyl ether acetate, and ethylene glycol monobutyl ether acetate; polyethylene glycol monoalkyl ether acetates such as diethylene glycol monoethyl ether acetate, diethylene glycol monoethyl ether acetate, diethylene glycol monobutyl ether acetate, triethylene glycol monomethyl ether acetate, triethylene glycol monoethyl ether acetate, and triethylene glycol monobutyl ether acetate; and propylene glycol monoalkyl ether acetates such as propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, and propylene glycol monobutyl ether acetate.

Examples of ester solvents include methyl acetate, ethyl acetate, n-propyl acetate, isopropyl acetate, n-butyl acetate, benzyl acetate, ethyl propionate, ethyl butyrate, butyl butyrate, valerolactone, and butyrolactone.
etc.

Other solvents include, for example, dimethyl sulfoxide, sulfolane, γ-butyrolactone, N-methyl-2-pyrrolidone, etc.

In the manufacturing method (A), the solids concentration during the reaction is preferably 35 to 95% by mass. If a highly viscous product is produced during the reaction, the reaction can be continued by adding additional solvent. After the reaction is completed, the solvent can be removed or further added as necessary.

The reaction temperature is within a range in which the catalyst used does not decompose. If the reaction temperature is too high, the catalyst may decompose and the reaction may stop, or the phenoxy resin produced may deteriorate. If the reaction temperature is too low, the reaction may not proceed sufficiently to achieve the desired molecular weight. Therefore, the reaction temperature is preferably 50 to 230°C, more preferably 120 to 200°C. The reaction time is usually 1 to 12 hours, preferably 3 to 10 hours. When using a low-boiling solvent such as acetone or methyl ethyl ketone, the reaction temperature can be ensured by using an autoclave to carry out the reaction under high pressure. If it is necessary to remove the heat of reaction, this is usually done by evaporating, condensing, and refluxing the solvent used using the heat of reaction, indirect cooling, or a combination of these.

Next, the production method (B) of the present invention will be described.
The production method (B) is a method for obtaining a phenoxy resin (a) represented by formula (6) having a weight average molecular weight of 10,000 to 200,000, i.e., the phenoxy resin of the present invention, by reacting the phenoxy resin (a) represented by formula (6) with 0.05 mol or more and 2.0 mol or less of an acyl group of an acylating agent per 1 mol of the alcoholic hydroxyl group of the phenoxy resin (a).

The raw material phenoxy resin (a) essentially contains an alkenyl-containing aromatic group in X in formula (6). The alkenyl-containing aromatic group is preferably one represented by formula (2) or formula (3).
This phenoxy resin (a) can be obtained by a conventionally known method. For example, it can be produced by reacting a bifunctional phenolic compound that requires an alkenyl-containing aromatic group with epihalohydrin in the presence of an alkali metal compound (hereinafter referred to as "one-step method"); or by reacting a bifunctional epoxy resin containing an alkenyl-containing aromatic group with a bifunctional phenolic compound in the presence of a catalyst (hereinafter referred to as "two-step method"). The phenoxy resin (a) can be obtained by any method, but it is generally easier to obtain phenoxy resin by the two-step method than by the one-step method, so it is preferable to use the two-step method.

The weight average molecular weight and epoxy equivalent of the phenoxy resin (a) can be produced within the desired range by appropriately adjusting the molar ratio of the epihalohydrin and bifunctional phenolic compounds in the one-stage process, and by appropriately adjusting the molar ratio of the bifunctional epoxy resins and bifunctional phenolic compounds in the two-stage process.

The bifunctional phenol compounds used in the one-stage and two-stage production processes must essentially be bifunctional phenol compounds having an alkenyl group.
Examples of bifunctional phenol compounds having an alkenyl group include diallyl bisphenol A, diallyl bisphenol S, and diallyl dihydroxynaphthalene.

Other bifunctional phenol compounds may be used in combination as long as the object of the present invention is not impaired. Examples of bifunctional phenol compounds that may be used in combination include bisphenols such as bisphenol A, bisphenol F, bisphenol S, bisphenol B, bisphenol E, bisphenol C, bisphenolacetophenone, bisphenolfluorene, dihydroxybiphenyl ether, and dihydroxybiphenyl thioether, biphenols such as 4,4'-biphenol and 2,4'-biphenol, and 1,1-bi-2-naphthol.
In addition, a plurality of types of these difunctional phenol compounds may be used in combination.

First, the one-stage process will be described.
In the case of the one-step process, 0.985 to 1.015 moles, preferably 0.99 to 1.012 moles, more preferably 0.995 to 1.01 moles of epihalohydrin are reacted with 1 mole of bifunctional phenolic compounds in a non-reactive solvent in the presence of an alkali metal compound, and the condensation reaction is carried out so that the epihalohydrin is consumed and the weight average molecular weight is 10,000 or more, thereby obtaining a phenoxy resin (a). After the reaction is completed, it is necessary to remove the by-product salt by filtration or washing with water. Examples of the alkali metal compound include the same alkali metal compounds as those used in the production of the bifunctional epoxy resin represented by formula (4) as the raw material used in the production method (A) of the present invention.

This reaction can be carried out under normal pressure or reduced pressure. In the case of reactions under normal pressure, the reaction temperature is usually preferably 20 to 200°C, more preferably 30 to 170°C, even more preferably 40 to 150°C, and particularly preferably 50 to 100°C. In the case of reactions under reduced pressure, the reaction temperature is preferably 20 to 100°C, more preferably 30 to 90°C, and even more preferably 35 to 80°C. If the reaction temperature is within this range, side reactions are unlikely to occur and the reaction is easy to proceed. The reaction pressure is usually normal pressure. In addition, when it is necessary to remove the heat of reaction, this is usually done by evaporation/condensation/reflux method of the solvent used using the heat of reaction, indirect cooling method, or a combination of these.

As the reactive solvent, in addition to the reaction solvents exemplified in the production method (A) of the present invention, alcohols such as ethanol, isopropyl alcohol, and butyl alcohol can also be used. Only one type may be used, or two or more types may be used in combination.

Next, the two-stage method will be described.
As the bifunctional epoxy resin serving as the raw material epoxy resin in the two-stage process, one similar to the bifunctional epoxy resin represented by formula (4) used in the production process (A) of the present invention is used.

As the bifunctional epoxy resin used as the raw material for the two-stage process, the bifunctional epoxy resin represented by formula (4) is preferred, but other bifunctional epoxy resins may be used in combination as long as the object of the present invention is not impaired. Examples of bifunctional epoxy resins that can be used in combination include bisphenol type epoxy resins such as bisphenol A type epoxy resins, bisphenol F type epoxy resins, bisphenol S type epoxy resins, bisphenol acetophenone type epoxy resins, diphenyl sulfide type epoxy resins, and diphenyl ether type epoxy resins, biphenol type epoxy resins, diphenyl dicyclopentadiene type epoxy resins, alkylene glycol type epoxy resins, and aliphatic cyclic epoxy resins. These epoxy resins may be substituted with substituents such as alkyl groups and aryl groups that have no adverse effects. Multiple types of these epoxy resins may be used in combination.

In the case of the two-stage method, a catalyst can be used, and any compound having catalytic ability to promote the reaction between the epoxy group and the phenolic hydroxyl group can be used. For example, the same catalysts as those exemplified in the production method (A) of the present invention can be used. In addition, the alkali metal compounds used in the production of the bifunctional epoxy resin represented by formula (4) can also be used. These catalysts can be used alone or in combination of two or more types. The amount used is also the same as the amount exemplified in the production method (A) of the present invention.

In the case of the two-stage method, a solvent may be used. Any solvent may be used as long as it dissolves the phenoxy resin and does not adversely affect the reaction. For example, the same solvents as those exemplified in the manufacturing method (A) of the present invention may be used. These solvents may be used alone or in combination of two or more.

The amount of solvent used can be appropriately selected depending on the reaction conditions. For example, in the case of a two-stage process, a solids concentration of 35 to 95% by mass is preferred. If a highly viscous product is produced during the reaction, the reaction can be continued by adding solvent during the reaction. After the reaction is completed, the solvent can be removed by distillation or the like as necessary, or more solvent can be added.

The reaction temperature is within a range in which the catalyst used does not decompose. If the reaction temperature is too high, the catalyst may decompose and the reaction may stop, or the phenoxy resin produced may deteriorate. If the reaction temperature is too low, the reaction may not proceed sufficiently to achieve the desired molecular weight. Therefore, the reaction temperature is preferably 50 to 230°C, more preferably 100 to 210°C, and even more preferably 120 to 200°C. The reaction time is usually 1 to 12 hours, and preferably 3 to 10 hours. When using a low-boiling solvent such as acetone or methyl ethyl ketone, the reaction temperature can be ensured by carrying out the reaction under high pressure using an autoclave. If it is necessary to remove the heat of reaction, this is usually done by evaporating, condensing, and refluxing the solvent used using the heat of reaction, indirect cooling, or a combination of these.

The phenoxy resin of the present invention can be obtained by acylation of the hydroxyl groups in the phenoxy resin (a) represented by formula (6) obtained in this manner. Acylation can be achieved not only by direct esterification but also by a method such as transesterification.

The acid component used for acylation may be, for example, organic acids such as acetic acid, propionic acid, butyric acid, isobutyric acid, pentanoic acid, octanoic acid, caprylic acid, lauric acid, stearic acid, oleic acid, benzoic acid, t-butylbenzoic acid, hexahydrobenzoic acid, phenoxyacetic acid, acrylic acid, and methacrylic acid, as well as acid anhydrides of organic acids, organic acid halides, and organic acid esters. Among these acylating agents, the acid anhydrides represented by the following formula (7) are preferred.

式中、Ｚ^２は炭素数２～２０のアシル基である。

In the formula, ^Z2 is an acyl group having 2 to 20 carbon atoms.

Examples of the acid anhydrides of organic acids include acetic anhydride, benzoic anhydride, and phenoxyacetic anhydride.
Examples of the esters of organic acids include methyl acetate, ethyl acetate, butyl acetate, methyl benzoate, ethyl benzoate, etc. Examples of the halides of organic acids include acetate chloride, benzoate chloride, phenoxyacetate chloride, etc.

Compounds used for esterification are preferably organic acid halides such as acetic acid chloride, benzoic acid chloride, and phenoxyacetic acid chloride, acid halides such as acetic anhydride, benzoic acid anhydride, and phenoxyacetic acid anhydride, and acid anhydrides of organic acids. Acid anhydrides such as acetic anhydride and benzoic acid anhydride are more preferable because they do not require washing with water after esterification and they avoid the inclusion of halogens, which are undesirable in electrical material applications.

The charge ratio of an acid component such as an organic acid, an acid anhydride of an organic acid, an organic acid halide, or an ester of an organic acid used for esterifying the hydroxyl groups of the phenoxy resin (a) when reacting the phenoxy resin (a) with the phenoxy resin (a) may be the same as the target esterification ratio, or when the reactivity is low, the acid component may be charged in excess relative to the hydroxyl groups, and after reacting until the target esterification ratio is reached, the unreacted acid component may be removed.
Here, the amount of the acylating agent used relative to the raw material phenoxy resin (a) is 0.05 mol or more and 2.0 mol or less, preferably 0.1 to 1.0 mol, and more preferably 0.2 to 0.8 mol of the acyl group of the acylating agent relative to 1 mol of the alcoholic hydroxyl group of the phenoxy resin (a). When the acylating agent is an acid anhydride represented by formula (7), it is understood that the acylating agent has 2 mol of the acyl group relative to 1 mol of the acylating agent.

When directly esterifying with an acid component, it can be carried out while dehydrating using various esterification catalysts, such as acid catalysts such as paratoluenesulfonic acid and phosphoric acid, and metal catalysts such as tetraisopropyl titanate, tetrabutyl titanate, dibutyltin oxide, dioctyltin oxide, and zinc chloride. It is usually preferably carried out at 100 to 250°C under a nitrogen atmosphere, and more preferably at 130 to 230°C.

When an acid halide or an acid anhydride is used for esterification, the acid produced can be removed by any of the following methods: neutralizing with a basic compound and then filtering the salt; neutralizing with a basic compound and then washing with water; washing with water without neutralization; or removing the acid by distillation or adsorption. These methods may be used in combination. When removing an acid with a lower boiling point than the reaction solvent, it is preferable to remove it by distillation.

When phenoxy resin (a) is esterified by ester exchange, it is usually desirable to carry out the esterification under a nitrogen atmosphere while dealcoholizing the resin using a known esterification catalyst, such as dibutyltin oxide, dioctyltin oxide, stannoxane catalyst, tetraisopropyl titanate, tetrabutyl titanate, lead acetate, zinc acetate, antimony trioxide, or other organometallic catalyst, acid catalyst such as hydrochloric acid, sulfuric acid, phosphoric acid, or sulfonic acid, or basic catalyst such as lithium hydroxide or sodium hydroxide.

In the manufacturing method (B) of the present invention, a solvent for the reaction may be used, and any solvent that dissolves the phenoxy resin may be used. For example, the solvents exemplified in the manufacturing method (A) of the present invention may be used. These solvents may be the same as or different from those used in the preparation of the phenoxy resin (a). In addition, only one type may be used, or two or more types may be used in combination.

The resin composition of the present invention is a resin composition that contains a phenoxy resin represented by formula (1) as an essential component, and has either a radical polymerization initiator or a curing agent, or both. The resin composition of the present invention may further contain a thermosetting resin, and various additives such as inorganic fillers, coupling agents, and antioxidants can be appropriately blended as necessary. The resin composition of the present invention gives a cured product that fully satisfies the various physical properties required for various applications.

In the present invention, the curing agent refers to a substance that contributes to the crosslinking reaction with the phenoxy resin. In the present invention, even a substance called a curing accelerator is considered to be a curing agent as long as it contributes to the crosslinking reaction and/or chain extension reaction of the phenoxy resin. The curing reaction in the present invention is a crosslinking reaction with an alkenyl group or a crosslinking reaction with an epoxy group.
The amount of the radical polymerization initiator or the curing agent is 0.1 to 30 parts by mass, more preferably 0.1 to 25 parts by mass or less, and even more preferably 0.1 to 10 parts by mass or less, based on 100 parts by mass of the solid content of the phenoxy resin. The mass ratio of the solid content of the phenoxy resin to the thermosetting resin is 99/1 to 1/99, more preferably 90/10 to 70/30, and even more preferably 80/20 to 40/60.

The curing agent used in the resin composition of the present invention is not particularly limited, and any agent generally known as a curing agent for an alkenyl group can be used. Examples of the curing agent include radical polymerization initiators, maleimide compounds, vinyl compounds, and the like.
As the radical polymerization initiator (also called radical polymerization catalyst), for example, the resin composition of the present invention is cured by a crosslinking reaction caused by heating or the like as described later, and a radical polymerization initiator may be contained for the purpose of lowering the reaction temperature at that time or promoting the crosslinking reaction of unsaturated groups. Since the radical polymerization initiator is a radical polymerization catalyst, it will be represented by the radical polymerization initiator hereinafter.

Representative examples of radical polymerization initiators include peroxides such as benzoyl peroxide, cumene hydroperoxide, 2,5-dimethylhexane-2,5-dihydroperoxide, 2,5-dimethyl-2,5-di(t-butylperoxy)hexyne-3, di-t-butyl peroxide, t-butylcumyl peroxide, α,α'-bis(t-butylperoxy-m-isopropyl)benzene, 2,5-dimethyl-2,5-di(t-butylperoxy)hexane, dicumyl peroxide, di-t-butylperoxyisophthalate, t-butylperoxybenzoate, 2,2-bis(t-butylperoxy)butane, 2,2-bis(t-butylperoxy)octane, 2,5-dimethyl-2,5-di(benzoylperoxy)hexane, di(trimethylsilyl)peroxide, and trimethylsilyltriphenylsilyl peroxide, but are not limited to these. Although it is not a peroxide, 2,3-dimethyl-2,3-diphenylbutane can also be used as a radical polymerization initiator (or polymerization catalyst). However, the catalyst and radical polymerization initiator used to cure the present resin composition are not limited to these examples.

Representative examples of vinyl compounds include, but are not limited to, trialkenyl isocyanurate compounds such as triallyl isocyanurate (TAIC), vinylbenzyl compounds such as styrene and divinylbenzene, etc.

Representative examples of thermosetting resins include maleimide resins, epoxy resins, vinyl ester resins, polyvinylbenzyl resins, polyallyl resins, oxetane resins, acrylate resins, polyester resins, polyurethane resins, polycyanate resins, phenolic resins, and benzoxazine resins. Maleimide resins and epoxy resins are preferred from the standpoint of heat resistance and compatibility.

The maleimide resin (maleimide compound) that can be blended in the resin composition of the present invention is not particularly limited as long as it is a compound having one or more maleimide groups in one molecule, and also functions as a curing agent for the phenoxy resin represented by formula (1).
For example, N-phenylmaleimide, phenylmethane maleimide, N-hydroxyphenylmaleimide, 4,4'-diphenylmethane bismaleimide, 4,4-diphenylether bismaleimide, polyphenylmethane maleimide, m-phenylene bismaleimide, p-phenylene bismaleimide, 2,2'-[4-(4-maleimidophenoxy)phenyl]propane, 3,3'-dimethyl-5,5'-diethyl-4,4'-diphenylmethane bismaleimide, bis(3,5-dimethyl-4-maleimidophenyl)methane, bis-(3-ethyl-5-methyl-4-maleimidophenyl) )methane, bis(3,5-diethyl-4-maleimidophenyl)methane, 4-methyl-1,3-phenylene bismaleimide, 4,4'-diphenylether bismaleimide, 4,4'-diphenylsulfone bismaleimide, 1,3-bis(3-maleimidophenoxy)benzene, 1,3-bis(4-maleimidophenoxy)benzene, N,N'-ethylene dimaleimide, N,N'-hexamethylene dimaleimide, maleimide resins represented by the following general formula (9), prepolymers of these maleimide compounds, or prepolymers of maleimide compounds and amine compounds. These maleimide compounds can be used in combination of one or more. Among these, phenylmethane maleimide oligomers and maleimide resins represented by the following general formula (9) are preferred.

ここで、
Ｒ^７は独立に、水素原子又はメチル基を示す。
Ｒ^８は独立に、炭素数１～５のアルキル基又は芳香族基を示す。
ａは０～４の整数であり、０又は１が好ましい。
ｂは０～３の整数であり、０又は１が好ましい。
ｒ及びｑは０又は１である。
ｓは繰り返し数であり、その平均値は１～１０であり、１～７が好ましく、１～５がより好ましい。

here,
^R7 independently represents a hydrogen atom or a methyl group.
^R8 independently represents an alkyl group having 1 to 5 carbon atoms or an aromatic group.
a is an integer of 0 to 4, with 0 or 1 being preferred.
b is an integer of 0 to 3, with 0 or 1 being preferred.
r and q are 0 or 1.
s is the number of repetitions, the average value of which is from 1 to 10, preferably from 1 to 7, and more preferably from 1 to 5.

As the epoxy resin to be blended in the resin composition of the present invention, one or more of various epoxy resins may be used as necessary. As the epoxy resin, any ordinary epoxy resin having two or more epoxy groups in the molecule can be used. For example, trifunctional epoxy resins such as bisphenol A type epoxy resins, bisphenol F type epoxy resins, bisphenol AF type epoxy resins, tetramethylbisphenol F type epoxy resins, hydroquinone type epoxy resins, biphenyl type epoxy resins, stilbene type epoxy resins, bisphenol fluorene type epoxy resins, bisphenol S type epoxy resins, bisthioether type epoxy resins, resorcinol type epoxy resins, biphenyl aralkylphenol type epoxy resins, naphthalene diol type epoxy resins, phenol novolac type epoxy resins, aromatic modified phenol novolac type epoxy resins, cresol novolac type epoxy resins, alkyl novolac type epoxy resins, bisphenol novolac type epoxy resins, binaphthol type epoxy resins, naphthol novolac type epoxy resins, β-naphthol aralkyl type epoxy resins, dinaphthol aralkyl type epoxy resins, α-naphthol aralkyl type epoxy resins, trisphenylmethane type epoxy resins, and tetrafunctional epoxy resins such as tetrakisphenylethane type epoxy resins. , dicyclopentadiene type epoxy resins, polyhydric alcohol polyglycidyl ethers such as 1,4-butanediol diglycidyl ether, 1,6-hexanediol diglycidyl ether, glycerol polyglycidyl ether, trimethylolpropane polyglycidyl ether, trimethylolethane polyglycidyl ether, and pentaerythritol polyglycidyl ether, alkylene glycol type epoxy resins such as propylene glycol diglycidyl ether, aliphatic cyclic epoxy resins such as cyclohexanedimethanol diglycidyl ether, glycidyl esters such as dimer acid polyglycidyl ester, glycidyl amine type epoxy resins such as phenyl diglycidyl amine, tolyl diglycidyl amine, diaminodiphenylmethane tetraglycidyl amine, and aminophenol type epoxy resins, alicyclic epoxy resins such as Celloxide 2021P (manufactured by Daicel Corporation), phosphorus-containing epoxy resins, bromine-containing epoxy resins, urethane-modified epoxy resins, and oxazolidone ring-containing epoxy resins, but are not limited thereto. These epoxy resins may be used alone or in combination of two or more. From the viewpoint of availability, it is more preferable to use an epoxy resin represented by the following general formula (10), a dicyclopentadiene type epoxy resin, a naphthalene diol type epoxy resin, a phenol novolac type epoxy resin, an aromatic modified phenol novolac type epoxy resin, a cresol novolac type epoxy resin, an α-naphthol aralkyl type epoxy resin, a dicyclopentadiene type epoxy resin, a phosphorus-containing epoxy resin, or an oxazolidone ring-containing epoxy resin.

ここで、
Ｒ^５は独立に炭素数１～８の炭化水素基を示し、例えば、メチル基、エチル基、ｎ－プロピル基、イソプロピル基、ｎ－ブチル基、ｔ－ブチル基、ｎ－ヘキシル基、シクロヘキシル基等のアルキル基であり、お互いに同じであっても異なっていてもよい。
Ｖは２価の有機基を示し、例えば、メチレン基、エチレン基、イソプロピレデン基、イソブチレン基、ヘキサフルオロイソプロピリデン基等のアルキレン基、－ＣＯ－、－Ｏ－、－Ｓ－、－ＳＯ_２－、－Ｓ－Ｓ－、又は式（１０ａ）で示されるアラルキレン基を示す。
Ｒ^６は独立に、水素原子又は炭素数１以上の炭化水素基を示し、例えば、メチル基であり、お互いに同じであっても異なっていてもよい。
Ａｒはベンゼン環又はナフタレン環であり、これらのベンゼン環又はナフタレン環は、炭素数１～１０のアルキル基、炭素数１～１０のアルコキシ基、炭素数６～１１のアリール基、炭素数７～１２のアラルキル基、炭素数６～１１のアリールオキシ基、又は炭素数７～１２のアラルキルオキシ基を置換基として有してもよい。

here,
^R5 independently represents a hydrocarbon group having 1 to 8 carbon atoms, for example, an alkyl group such as a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, a t-butyl group, an n-hexyl group, or a cyclohexyl group, and may be the same or different from each other.
V represents a divalent organic group, for example, an alkylene group such as a methylene group, an ethylene group, an isopropylidene group, an isobutylene group or a hexafluoroisopropylidene group, -CO-, -O-, -S-, -SO ₂ -, -S-S-, or an aralkylene group represented by the formula (10a).
^R6 independently represents a hydrogen atom or a hydrocarbon group having 1 or more carbon atoms, for example, a methyl group, and may be the same or different from each other.
Ar is a benzene ring or a naphthalene ring, and the benzene ring or the naphthalene ring may have, as a substituent, an alkyl group having 1 to 10 carbon atoms, an alkoxy group having 1 to 10 carbon atoms, an aryl group having 6 to 11 carbon atoms, an aralkyl group having 7 to 12 carbon atoms, an aryloxy group having 6 to 11 carbon atoms, or an aralkyloxy group having 7 to 12 carbon atoms.

When an epoxy resin is used in the resin composition of the present invention, an epoxy resin curing agent can be used as necessary. As the epoxy resin curing agent, generally known ones can be used, and examples thereof include phenol-based curing agents, amine-based curing agents, acid anhydride-based curing agents, and phosphorus-based curing agents. The above-mentioned cationic polymerization initiator can also be used as an epoxy resin curing agent. These curing agents may be used alone or in combination of two or more kinds.

When the vinyl resin to be blended is one or more vinyl compounds having one or more polymerizable unsaturated hydrocarbon groups in the molecule, the type is not particularly limited. In other words, the vinyl compounds may be any compounds that can be crosslinked and cured by reacting with the phenoxy resin of the present invention. It is more preferable that the polymerizable unsaturated hydrocarbon group is a carbon-carbon unsaturated double bond, and more preferable that the compound has two or more carbon-carbon unsaturated double bonds in the molecule.

Examples of vinyl resins include modified polyphenylene ether (PPE) whose ends are modified with (meth)acryloyl or styryl groups, polyfunctional (meth)acrylate resins having two or more (meth)acryloyl groups in the molecule, and vinyl resins (polyfunctional vinyl resins) having two or more vinyl groups in the molecule, such as polybutadiene.

The resin composition of the present invention may be blended with various polymeric compounds such as thermoplastic resins and thermoplastic elastomers to the extent that the properties are not impaired. Examples of thermoplastic resins include polystyrene resin, polyphenylene ether resin, polyetherimide resin, polyethersulfone resin, PPS resin, polycyclopentadiene resin, and polycycloolefin resin. Examples of thermoplastic elastomers include styrene-ethylene-propylene copolymer, styrene-ethylene-butylene copolymer, styrene-butadiene copolymer, styrene-isoprene copolymer, hydrogenated styrene-butadiene copolymer, and hydrogenated styrene-isoprene copolymer. It is also possible to blend rubbers such as polybutadiene and polyisoprene.

In the phenoxy resin composition of the present invention, various known flame retardants can be used to improve the flame retardancy of the resulting cured product, as long as the reliability is not reduced. Examples of flame retardants that can be used include halogen-based flame retardants, phosphorus-based flame retardants, nitrogen-based flame retardants, silicone-based flame retardants, inorganic flame retardants, and organic metal salt-based flame retardants. From an environmental perspective, halogen-free flame retardants are preferred, and phosphorus-based flame retardants are particularly preferred. These flame retardants can be used alone or in combination of two or more types.

The resin composition of the present invention may contain other components as necessary. Examples of such components include fillers such as silica and carbon fiber, thermoplastic resins, thermosetting resins, photocurable resins, ultraviolet protection agents, antioxidants, coupling agents, plasticizers, fluxes, thixotropy-imparting agents, smoothing agents, colorants, pigments, dispersants, emulsifiers, elasticity-reducing agents, release agents, antifoaming agents, and ion-trapping agents.
The blending amount of the other components is preferably within a range of 0.01 to 20% by mass based on the total solid content in the resin composition.

The resin composition of the present invention may contain a solvent to appropriately adjust the viscosity of the resin composition during handling.

These solvents are preferably used in an amount of 90% by mass or less as non-volatile matter, and the appropriate type and amount used are appropriately selected depending on the application. For example, for printed wiring board applications, polar solvents with a boiling point of 160°C or less, such as methyl ethyl ketone, acetone, and 1-methoxy-2-propanol, are preferred, and the amount used is preferably 40 to 80% by mass as non-volatile matter. For adhesive film applications, for example, ketones, acetates, carbitols, aromatic hydrocarbons, dimethylformamide, dimethylacetamide, and N-methylpyrrolidone are preferred, and the amount used is preferably 30 to 60% by mass as non-volatile matter.

The resin composition of the present invention can be obtained by uniformly mixing the above components. The resin composition containing the phenoxy resin of the present invention, a radical polymerization initiator or a curing agent, and various other components as necessary can be easily made into a cured product by a method similar to that known in the art. This cured product has an excellent balance of low moisture absorption, dielectric properties, heat resistance, adhesion, etc., and exhibits good cured physical properties. Curing here means intentionally curing the resin composition with heat and/or light, etc., and the degree of curing can be controlled depending on the desired physical properties and application.

The resin composition of the present invention can be cured in the same manner as known epoxy resin compositions to obtain a cured product. The same methods as known epoxy resin compositions can be used to obtain a cured product, and methods such as casting, injection, potting, dipping, drip coating, transfer molding, compression molding, etc., or laminating in the form of a resin sheet, resin-coated copper foil, prepreg, etc., and curing under heat and pressure to obtain a laminate are preferably used. The curing temperature is usually in the range of 80 to 300°C, and the curing time is usually about 10 to 360 minutes. This heating is preferably performed in two stages, with a primary heating at 80 to 180°C for 10 to 90 minutes and a secondary heating at 120 to 200°C for 60 to 150 minutes. In addition, in a compounding system in which the glass transition temperature (Tg) exceeds the secondary heating temperature, it is preferable to further perform a tertiary heating at 150 to 280°C for 60 to 120 minutes.

The prepreg obtained using the resin composition of the present invention will be described. As the sheet-like substrate, a woven or nonwoven fabric of inorganic fibers such as glass, or organic fibers such as polyester, polyamine, polyacrylic, polyimide, Kevlar, cellulose, etc. can be used, but is not limited thereto. The method for producing a prepreg from the resin composition of the present invention and substrate is not particularly limited, and for example, the substrate is immersed in a resin varnish in which the viscosity of the resin composition is adjusted with a solvent, and then heated and dried to semi-cure (B-stage) the resin component, and the prepreg can be obtained, for example, by heating and drying at 100 to 200°C for 1 to 40 minutes. Here, the amount of resin in the prepreg is preferably 30 to 80% by mass.

A method for manufacturing a laminate using a prepreg or an insulating adhesive sheet will be described. When forming a laminate using a prepreg, one or more prepregs are laminated, a metal foil is placed on one or both sides to form a laminate, and the laminate is heated and pressed to laminate and integrate. Here, as the metal foil, a single metal foil, an alloy metal foil, or a composite metal foil such as copper, aluminum, brass, or nickel can be used. The conditions for heating and pressing the laminate may be appropriately adjusted under conditions under which the resin composition is cured, but if the pressure is too low, air bubbles may remain inside the obtained laminate, and the electrical properties may be reduced, so it is desirable to pressurize under conditions that satisfy moldability. For example, the temperature can be set to 160 to 220°C, the pressure to 49.0 to 490.3 N/cm ² (5 to 50 kgf/cm ² ), and the heating time to 40 to 240 minutes. It is also preferable to mold in a nitrogen atmosphere.

Furthermore, a multilayer board can be produced by using the laminate obtained in this way as an inner layer material. In this case, first, a circuit is formed on the laminate by an additive method, a subtractive method, or the like, and the surface of the formed circuit is blackened by treating it with an acid solution to obtain an inner layer material. An insulating layer is formed on one or both circuit-forming surfaces of this inner layer material using a prepreg or an insulating adhesive sheet, and a conductor layer is formed on the surface of the insulating layer to form a multilayer board.

When forming an insulating layer using an insulating adhesive sheet, an insulating adhesive sheet is placed on the circuit-forming surface of multiple inner layer materials to form a laminate. Alternatively, an insulating adhesive sheet is placed between the circuit-forming surface of the inner layer material and a metal foil to form a laminate. Then, this laminate is heated and pressurized to be integrally molded, thereby forming the cured product of the insulating adhesive sheet as an insulating layer and forming a multi-layered inner layer material. Alternatively, the inner layer material and the metal foil as a conductor layer form the cured product of the insulating adhesive sheet as an insulating layer. Here, the metal foil can be the same as that used in the laminate used as the inner layer material.
The hot and press molding can be carried out under the same conditions as those for molding the inner layer material. When forming an insulating layer by applying a resin composition to a laminate, the resin composition is applied to the circuit forming surface of the outermost layer of the inner layer material, preferably to a thickness of 5 to 100 μm, and then heated and dried at 100 to 200° C. for 1 to 90 minutes to form a sheet. It is generally formed by a method called a casting method. It is desirable to form the thickness after drying to 5 to 80 μm. A printed wiring board can be formed by further forming via holes and circuits on the surface of the multilayer laminate formed in this way by an additive method or a subtractive method.
Furthermore, by repeating the above-mentioned process using this printed wiring board as an inner layer material, a multi-layer laminate can be formed.

When forming an insulating layer using prepreg, one or more prepreg sheets are placed on the circuit forming surface of the inner layer material, and a metal foil is placed on the outside of the prepreg to form a laminate. This laminate is then heated and pressurized to form an integral mold, whereby the cured prepreg is formed as an insulating layer, and the outer metal foil is formed as a conductor layer.
Here, the metal foil may be the same as that used in the laminate used as the inner layer material. The hot press molding may be performed under the same conditions as those for molding the inner layer material. The surface of the multilayer laminate thus molded may be further subjected to via hole formation or circuit formation by an additive method or a subtractive method to mold a printed wiring board.
Furthermore, by repeating the above process using this printed wiring board as an inner layer material, a multi-layer board with even more layers can be formed.

The cured products and laminates for electrical and electronic circuits obtained from the resin composition of the present invention have excellent flame retardancy and heat resistance.

The present invention will be described in more detail below based on examples and comparative examples, but the present invention is not limited thereto. Unless otherwise specified, parts means "parts by mass" and % means "% by mass". Analytical and measuring methods are shown below. In addition, the unit of various equivalents is "g/eq.".

(1) Weight average molecular weight (Mw):
It was obtained by GPC measurement. Specifically, a main body HLC8320GPC (manufactured by Tosoh Corporation) equipped with columns (TSKgel SuperH-H, SuperH2000, SuperHM-H, SuperHM-H, all manufactured by Tosoh Corporation) in series was used, and the column temperature was set to 40 ° C. The eluent was tetrahydrofuran (THF), the flow rate was 1 mL / min, and the detector was a differential refractive index detector. The measurement sample was 20 μL of a solid content of 0.1 g dissolved in 10 mL of THF and filtered through a 0.45 μm microfilter. Mw was calculated by conversion from a calibration curve obtained from standard polyethylene oxide (manufactured by Tosoh Corporation, SE-2, SE-5, SE-8, SE-15, SE-30, SE-70, SE-150). The data was processed using GPC8020 Model II Version 6.00 manufactured by Tosoh Corporation.

(2) Non-volatile content:
The measurement was performed in accordance with JIS K7235. The drying temperature was 220° C., and the drying time was 60 minutes.

(3) Glass transition temperature (Tg):
Glass transition temperature (Tg): Measured according to JIS C6481. Expressed as the tan δ peak top when measured using a dynamic viscoelasticity measuring device (Hitachi High-Tech Science Corporation, EXSTAR DMS6100) at a temperature increase rate of 5° C./min.

(4) Dielectric properties:
The measurement was performed in accordance with IPC-TM-650 2.5.5.9. Specifically, the dielectric loss tangent at a frequency of 1 GHz was determined by a capacitance method using a material analyzer (manufactured by AGILENT Technologies).

(5) Solution Viscosity:
The viscosity was measured according to the JIS Z8803 standard, using a single cylinder type rotational viscometer. Specifically, a resin solution adjusted to a non-volatile content of 40% by weight was placed in a beaker, and the viscosity was measured at 25° C. using a B-type viscometer.

(6) Epoxy equivalent:
This was in accordance with JIS K7236. Specifically, a potentiometric titration device was used, chloroform was used as a solvent, a tetraethylammonium bromide acetate solution was added, and a 0.1 mol/L perchloric acid-acetic acid solution was used.

(7) Alkenyl equivalent:
The measurement was performed in accordance with JIS K0070. Specifically, the sample was reacted with Wiess solution (iodine monochloride solution) and left in a dark place, and then the excess iodine chloride was reduced to iodine, and the iodine content was titrated with sodium thiosulfate to calculate the iodine value. The iodine value was converted to an alkenyl equivalent.

(8) Hydroxyl equivalent:
The measurement was performed in accordance with JIS K0070. Specifically, a potentiometric titrator was used, 1,4-dioxane was used as a solvent, acetylation was performed with 1.5 mol/L acetyl chloride, excess acetyl chloride was decomposed with water, and titration was performed with 0.5 mol/L potassium hydroxide.

(9) Solvent resistance:
50 g of tetrahydrofuran was placed in a sample bottle, 1 g of the cured product was immersed therein, and the mixture was left at room temperature for 12 hours or more, and the state was visually observed.
◯: Not dispersed, and the hardened product is maintained.
×: Dispersed or swollen, unable to maintain the cured product.

The abbreviations used in the examples and comparative examples are as follows:

Ａ２：ビスフェノールＡ型液状エポキシ樹脂（日鉄ケミカル＆マテリアル株式会社製、エポトートＹＤ－１２８、エポキシ当量１８６、ｍ≒０．０９）

Ａ３：２，５－ジ－ｔ－ブチルヒドロキノン型エポキシ樹脂（日鉄ケミカル＆マテリアル株式会社製、エポトートＹＤＣ－１３１２、エポキシ当量１５４、ｍ≒０．０５）

[Bifunctional epoxy resin]
A1: Diallyl bisphenol A type epoxy resin obtained in Synthesis Example 1 (epoxy equivalent: 225, m ≒ 0.07)

A2: Bisphenol A type liquid epoxy resin (manufactured by Nippon Steel Chemical & Material Co., Ltd., Epotohto YD-128, epoxy equivalent 186, m≒0.09)

A3: 2,5-di-t-butylhydroquinone type epoxy resin (manufactured by Nippon Steel Chemical & Material Co., Ltd., Epotohto YDC-1312, epoxy equivalent 154, m≒0.05)

Ｂ２：合成例３で得た２，７－ジアセトキシ－ジアリルナフタレン（活性エステル当量＝１５４）

Ｂ３：合成例４で得たジアセトキシフェノールフタレイン（活性エステル当量＝２０１）

Ｂ４：２，７－ジアセトキシナフタレン（富士フイルム和光純薬株式会社製、活性エステル当量＝１２２）

Ｂ５：４，４－ジアセトキシビフェニル（富士フィルム和光純薬株式会社製、活性エステル当量＝１３５）

Ｂ６：合成例５で合成したジアセトキシ－ビスフェノールＳ（活性エステル当量＝１６７）

[Diester compounds]
B1: Diacetoxy-diallyl bisphenol S obtained in Synthesis Example 2 (active ester equivalent = 207)

B2: 2,7-diacetoxy-diallylnaphthalene obtained in Synthesis Example 3 (active ester equivalent = 154)

B3: Diacetoxyphenolphthalein obtained in Synthesis Example 4 (active ester equivalent = 201)

B4: 2,7-diacetoxynaphthalene (manufactured by Fujifilm Wako Pure Chemical Industries, active ester equivalent = 122)

B5: 4,4-diacetoxybiphenyl (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd., active ester equivalent = 135)

B6: Diacetoxy-bisphenol S (active ester equivalent = 167) synthesized in Synthesis Example 5

[Bifunctional phenol compound]
C1: Diallyl bisphenol A (manufactured by Daiwa Chemical Industry Co., Ltd., hydroxyl equivalent: 154)
C2: Diallyl bisphenol S (WEIFANG DAYOO BIOCHEMICAL CO., LTD., hydroxyl equivalent 165)
C3: 2,7-naphthalenediol (Tokyo Chemical Industry Co., Ltd., hydroxyl equivalent: 80)
C4: Phenolphthalein (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd., hydroxyl equivalent: 159)

[catalyst]
D1: N,N'-dimethylaminopyridine (Tokyo Chemical Industry Co., Ltd.)
D2: Tetrabutylphosphonium tetraphenylborate (manufactured by Nippon Chemical Industry Co., Ltd., Hishicolin PX-4PB)
D3: Pyridine (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.)

[Solvents]
S1: Cyclohexanone S2: Methyl ethyl ketone (MEK)

[Acid anhydride]
E1: Acetic anhydride (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.)

[Curing agent]
H1: Phenylmethanemaleimide oligomer (manufactured by Daiwa Chemical Industry Co., Ltd., BMI-2300)

[Peroxide]
Z1: α,α'-bis(2-t-butylperoxyisopropyl)benzene (Perbutyl P, manufactured by NOF Corporation)

Synthesis Example 1
In a reaction apparatus equipped with a stirrer, a thermometer, a nitrogen blowing tube, a dropping funnel, and a cooling tube, 400 parts of diallyl bisphenol A (C1) and 720 parts of epichlorohydrin were added and heated to 65°C. Under a reduced pressure of 125 mmHg, while maintaining the temperature at 63 to 67°C, 200 parts of 49% aqueous sodium hydroxide solution were dropped over 4 hours. During this time, epichlorohydrin was azeotroped with water, and the water that flowed out was sequentially removed from the system. After the reaction was completed, epichlorohydrin was recovered under conditions of 5 mmHg and 140°C, and 600 parts of methyl isobutyl ketone was added to dissolve the product. Thereafter, 150 parts of water was added to dissolve the by-produced salt, and the solution was left to stand and the lower layer of saline was separated and removed. After neutralization with an aqueous phosphoric acid solution, the resin solution was washed with water until the washing water became neutral, and then filtered. The mixture was heated to 150° C. under a reduced pressure of 5 mmHg to distill off methyl isobutyl ketone, yielding 500 parts of diallyl bisphenol A type epoxy resin (A1). The epoxy equivalent was 225, m=0.07, the total chlorine content was 1500 ppm, and the alkenyl equivalent was 219.

Synthesis Example 2
In a reaction apparatus equipped with a stirrer, a thermometer, a nitrogen inlet tube, a dropping funnel, and a cooling tube, 200 parts of diallyl bisphenol S (C2) and 250 parts of acetic anhydride (E1) were added and heated to 140° C. After stirring at 140° C. for 2 hours, unreacted C2 was removed under conditions of 5 mmHg and 180° C., and 220 parts of diacetoxy-diallyl bisphenol S (B1) was obtained. The alkenyl equivalent was 204.

Synthesis Example 3
Chem. Eur. J. 2015,21,9970. With reference to the method described therein, 2,7-naphthalenediol (C3) was used as a raw material to synthesize diallyl-2,7-dihydroxynaphthalene. The hydroxyl equivalent was 112. 168 parts of the synthesized diallyl-2,7-dihydroxynaphthalene, 210 parts of acetic anhydride (E1), and 158 parts of pyridine (D3) were added to a reaction apparatus equipped with a stirrer, a thermometer, a nitrogen inlet tube, a dropping funnel, and a cooling tube, and the mixture was heated to 120 ° C. After stirring at 120 ° C. for 3 hours, unreacted E1 was removed under conditions of 5 mmHg and 140 ° C., and 220 parts of 2,7-diacetoxy-diallylnaphthalene (B2) was obtained. The alkenyl equivalent was 152. The active ester equivalent was 154, calculated from the hydroxyl group equivalent of diallyl-2,7-dihydroxynaphthalene.

Synthesis Example 4
Into a reaction apparatus equipped with a stirrer, a thermometer, a nitrogen inlet tube, a dropping funnel, and a cooling tube, 300 parts of phenolphthalein (C4) and 391 parts of acetic anhydride (E1) were added and heated to 140° C. After stirring at 140° C. for 3 hours, unreacted E1 was removed under conditions of 5 mmHg and 180° C., and 320 parts of diacetoxy-phenolphthalein (B3) was obtained.

Synthesis Example 5
The same procedure as in Synthesis Example 2 was repeated except that 153 parts of bisphenol S was used in place of diallyl bisphenol S, to synthesize 4,4-diacetoxy bisphenol S (B6).

Example 1
In a glass reaction vessel equipped with a stirrer, a thermometer, a nitrogen gas introduction device, a cooling tube, and a dropping device, 100 parts of the diallyl bisphenol A type epoxy resin (A1) obtained in Synthesis Example 1, 85.0 parts of the diacetoxyphenolphthalein (B3) obtained in Synthesis Example 4, and 46 parts of S1 as a reaction solvent were charged at room temperature, and the mixture was heated to 130 ° C. while stirring under nitrogen gas flow, and 0.1 parts of D1 were added as a catalyst, and then the mixture was heated to 145 ° C. and reacted at the same temperature for 7 hours. 46 parts of S1 and 185 parts of S2 were used as dilution solvents to dilute and mix, and a phenoxy resin varnish (R1) with a non-volatile content of 40% was obtained.

Examples 2 to 8, Comparative Examples 1 to 4
A phenoxy resin varnish was obtained in the same manner as in Example 1, using the amounts (parts) of each raw material shown in Table 1. The "molar ratio" in the table indicates the molar ratio of the difunctional epoxy resin to the diester compound and the difunctional phenol compound.

Example 9
The diallyl bisphenol A type epoxy resin (A1) obtained in Synthesis Example 1 was reacted with phenolphthalein (C4) to obtain a phenoxy resin varnish (RH1) obtained as Comparative Example 1, 100 parts (40 parts in solid content) was used, 600 parts of S1 were blended, and the temperature was raised to 100°C, after which 5 parts of acetic anhydride (E1) (0.22 moles per mole of alcoholic hydroxyl group of phenoxy resin RH1) were added and reacted for 4 hours. The obtained resin varnish was added to methanol, and the precipitated insoluble matter was filtered off, and the filtrate was dried in a vacuum dryer at 150°C and 0.4 kPa (3 torr) for 1 hour to obtain a phenoxy resin. 21 parts of S1 and 42 parts of S2 were added to the obtained phenoxy resin, and the mixture was dissolved uniformly to obtain a phenoxy resin varnish (R9) with a non-volatile content of 40%.

The Mw and solution viscosity were measured for the phenoxy resin varnishes R1 to R9 and RH1 to RH4 obtained in Examples 1 to 9 and Comparative Examples 1 to 4. The results are shown in Table 2.

The resin varnish was applied to a release film using a roller coater so that the thickness after solvent drying would be 60 μm, and after drying at 150°C for 60 minutes, the resulting dried film was peeled off from the release film. This dried film was pressed for 60 minutes using a vacuum press under conditions of a vacuum degree of 0.5 kPa, a heating temperature of 200°C, and a pressing pressure of 2 MPa to obtain a resin plate with a thickness of 1 mm. A spacer with a thickness of 1 mm was used to adjust the thickness. The dielectric properties and alkenyl equivalent of the resulting resin plate were measured. The results are shown in Table 2.

Table 2 shows the results of Mw, solution viscosity, dielectric properties, and alkenyl equivalent for the phenoxy resin varnishes R1 to R9 and RH1 to RH4 obtained in Examples 1 to 9 and Comparative Examples 1 to 4. In the table, "Xa rate" represents the content (mol%) of alkenyl-containing groups in all X, and "acylation rate" represents the content (mol%) of acyl groups in all Z. The examples using resin varnishes RH1 to RH4 are comparative examples.

As can be seen from Table 2, the phenoxy resins of the present invention shown in Examples 1 to 9 have excellent dielectric properties while having low viscosity (8000 mPa·s or less). In particular, when comparing Example 4 with Comparative Example 3, and Example 5 with Comparative Example 4, the only difference is the presence or absence of an alkenyl group, with no other structural differences. It can be seen that the presence of an alkenyl group results in low viscosity in the Examples and excellent dielectric properties. When comparing Example 8 with Comparative Example 2, the difference in acylation rate results in poor dielectric properties, but low viscosity.

Example 10, Comparative Example 5
The phenoxy resin varnish (R1, RH1) obtained in Example 1 and Comparative Example 1 was applied to a release film with a roller coater so that the thickness after solvent drying was 60 μm, and after drying at 150 ° C for 60 minutes, the dried film obtained was peeled off from the release film. 10 parts of the obtained dried film, 0.1 parts of Z1 as a radical polymerization initiator, and 10 parts of MEK were mixed to obtain a resin composition. Further, these were applied to a release film with a roller coater so that the thickness after solvent drying was 60 μm, and dried at 120 ° C for 15 minutes using a dryer, and the dried film was peeled off from the release film. This dried film was pressed for 80 minutes under conditions of a vacuum degree of 0.5 kPa, a heating temperature of 200 ° C, and a pressing pressure of 2 MPa to obtain a cured product with a thickness of 1 mm. In addition, a spacer of 1 mm was used for thickness adjustment.

Example 11
By the same procedure as in Example 10, a cured product of the phenoxy resin varnish (R2) was prepared.

Example 12
The same procedure as in Example 10 was repeated except that the amount of peroxide (Z1) was changed to 1 part, to prepare a cured product of phenoxy resin varnish (R2).

The dielectric properties and solvent resistance of the cured products obtained in Examples 10 to 12 and Comparative Example 5 were measured, and the results are shown in Table 3.

Examples 13 and 14, Comparative Examples 6 and 7
The phenoxy resin varnishes (R1, R5, RH1, RH4) obtained in Examples 1 and 5 and Comparative Examples 1 and 4 were applied to a release film with a roller coater so that the thickness after solvent drying was 60 μm, and after drying at 150 ° C for 60 minutes, the obtained dried film was peeled off from the release film. 10 parts of the obtained dried film, 2.5 parts of H1 as a curing agent, and 18.9 parts of MEK were blended to obtain a resin composition. These were further applied to a release film with a roller coater so that the thickness after solvent drying was 60 μm, and dried at 120 ° C for 15 minutes using a dryer, and the dried film was peeled off from the release film. This dried film was pressed for 80 minutes under conditions of a vacuum degree of 0.5 kPa, a heating temperature of 200 ° C, and a pressing pressure of 2 MPa to obtain a cured product with a thickness of 1 mm. In addition, a spacer of 1 mm was used for thickness adjustment.

The Tg, dielectric tangent, and solvent resistance of the cured products obtained in Examples 13 and 14 and Comparative Examples 6 and 7 were measured, and the results are shown in Table 4.

Examples 15 and 16, Comparative Examples 8 and 9
In the same manner as in Examples 13 and 14 and Comparative Examples 6 and 7, 0.1 parts of peroxide (Z1) was further added when the curing agent (H1) and MEK were mixed to prepare a cured product.

The Tg, dielectric tangent, and solvent resistance of the cured products obtained in Examples 15 and 16 and Comparative Examples 8 and 9 were measured, and the results are shown in Table 5.

As can be seen from Tables 4 and 5, the cured product made of the phenoxy resin and thermosetting resin of the present invention has excellent heat resistance and dielectric properties. In Comparative Examples 7 and 9, no cured product was obtained because there was no alkenyl group.

The phenoxy resin and resin composition of the present invention are applicable to various fields such as adhesives, paints, civil engineering building materials, and insulating materials for electric and electronic parts, and are particularly useful in the electric and electronic fields as insulating casting, lamination materials, sealing materials, etc. The phenoxy resin and resin composition containing the same of the present invention can be suitably used for multilayer printed wiring boards, laminates for electric and electronic circuits such as capacitors, adhesives such as film adhesives and liquid adhesives, semiconductor sealing materials, underfill materials, interchip fill materials for 3D-LSI, insulating sheets, prepregs, heat dissipation substrates, etc.

Claims (14)

A phenoxy resin represented by the following general formula (1) and having a weight average molecular weight of 10,000 to 200,000:

In the formula, X is a divalent group containing an alkenyl-containing aromatic group. Y is independently a hydrogen atom, an acyl group having 2 to 20 carbon atoms, or a glycidyl group. Z is an acyl group having 2 to 20 carbon atoms or a hydrogen atom, and 5 mol % or more of Z is an acyl group. n is the number of repetitions, and the average value is 15 or more and 500 or less. The phenoxy resin according to claim 1, wherein the alkenyl-containing aromatic group is an alkenyl-containing aromatic group represented by the following formula (2) and/or formula (3):

In the formula, A is a group selected from a direct bond, a divalent hydrocarbon group having 1 to 13 carbon atoms, -S-, -SO ₂ -, -SO-, -S-S-, -O-, -CO-, -COO-, and -C(CF ₃ ) ₂ -. R ¹ is an alkenyl group having 3 to 12 carbon atoms, and R ² is independently a hydrogen atom, an alkyl group having 1 to 12 carbon atoms, an alkoxy group having 1 to 12 carbon atoms, an aryl group having 6 to 12 carbon atoms, or an alkenyl group having 3 to 12 carbon atoms. k is 0 or 1. The phenoxy resin according to claim 1, wherein the alkenyl equivalent is 100 to 1000 g/eq. A resin composition comprising the phenoxy resin according to claim 1 and a radical polymerization initiator or a curing agent. The resin composition according to claim 4, which contains 0.1 to 30 parts by mass of a radical polymerization initiator or a curing agent per 100 parts by mass of the phenoxy resin. A resin composition comprising the phenoxy resin according to claim 1 and a thermosetting resin. The resin composition according to claim 6, wherein the mass ratio of the phenoxy resin to the thermosetting resin is 99/1 to 1/99. A cured product obtained by curing the resin composition according to any one of claims 4 to 7. A laminate for electrical/electronic circuits made using the resin composition according to any one of claims 4 to 7. A method for producing the phenoxy resin according to claim 1, comprising reacting a bifunctional epoxy resin represented by the following formula (4) with a compound represented by the following formula (5).

In the formula, ^X1 contains an alkenyl-containing aromatic group in at least one of formula (4) and formula (5). G is a glycidyl group. m is the number of repetitions, the average value of which is 0 to 6. ^Z1 is an acyl group having a hydrocarbon group having 2 to 20 carbon atoms or a hydrogen atom, and 5 mol % or more of Z1 is an acyl group. The method for producing a phenoxy resin according to claim 10, wherein the alkenyl-containing aromatic group is an alkenyl-containing aromatic group represented by the following formula (2) and/or formula (3):

In the formula, A is a group selected from a direct bond, a divalent hydrocarbon group having 1 to 13 carbon atoms, -S-, -SO ₂ -, -SO-, -S-S-, -O-, -CO-, -COO-, and -C(CF ₃ ) ₂ -. R ¹ is an alkenyl group having 3 to 12 carbon atoms, and R ² is independently a hydrogen atom, an alkyl group having 1 to 12 carbon atoms, an alkoxy group having 1 to 12 carbon atoms, an aryl group having 6 to 12 carbon atoms, or an alkenyl group having 3 to 12 carbon atoms. k is 0 or 1. A method for producing the phenoxy resin according to claim 1, comprising reacting 0.05 mol or more and 2.0 mol or less of an acyl group of an acylating agent with 1 mol of an alcoholic hydroxyl group of the phenoxy resin represented by the following formula (6):

In the formula, X and n are defined as X and n in formula (1). ^G1 independently represents a hydrogen atom or a glycidyl group. The method for producing a phenoxy resin according to claim 12, wherein X is an alkenyl-containing aromatic group represented by the following formula (2) and/or formula (3):

In the formula, A is a group selected from a direct bond, a divalent hydrocarbon group having 1 to 13 carbon atoms, -S-, -SO ₂ -, -SO-, -S-S-, -O-, -CO-, -COO-, and -C(CF ₃ ) ₂ -. R ¹ is an alkenyl group having 3 to 12 carbon atoms, and R ² is independently a hydrogen atom, an alkyl group having 1 to 12 carbon atoms, an alkoxy group having 1 to 12 carbon atoms, an aryl group having 6 to 12 carbon atoms, or an alkenyl group having 3 to 12 carbon atoms. k is 0 or 1. The method for producing a phenoxy resin according to claim 12 or 13, wherein the acylating agent is an acid anhydride represented by the following formula (7):

In the formula, ^Z2 is an acyl group having 2 to 20 carbon atoms.

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