JP7487326B2 - Modified phenoxy resin, its manufacturing method, resin composition, cured product, and laminate for electric/electronic circuits - Google Patents

Description

The present invention relates to a modified phenoxy resin that has excellent dielectric properties and storage stability. It also relates to a resin composition that contains the modified phenoxy resin and a curing agent and has excellent storage stability, a cured product thereof that has excellent 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 film molding base resins, 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 electrical and electronic circuits, etc., require excellent dielectric properties to prevent a decrease in insulation properties and the occurrence of malfunctions in electrical and electronic circuits.

In addition, when phenoxy resin is used as an electrical material such as laminates for electrical and electronic circuits, it is generally used as a mixture with multiple materials including epoxy resins and hardeners. However, it has become clear that phenoxy resins produced using amines, ammonium salts, and alkaline compounds as catalysts, as described in Non-Patent Document 1 below, have insufficient storage stability when mixed with other materials.

General Review of Epoxy Resins, Vol. 1, Basics I, Epoxy Resin Technology Association (2003)

The object of the present invention is to provide a phenoxy resin having excellent dielectric properties and storage stability. In addition, the object of the present invention is to provide a cured product having excellent dielectric properties by curing a resin composition containing the phenoxy resin.

In order to solve the above problems, the present inventors conducted extensive research into phenoxy resins and discovered that a phenoxy resin having a specific structure has excellent dielectric properties and storage stability, and further discovered that a cured product obtained by curing a resin composition containing this has excellent dielectric properties, thus completing the present invention.

ここで、Ｘは２価の基である。Ｙは炭素数２～２０のアシル基又は水素原子である。Ｚは炭素数２～２０のアシル基又は水素原子であり、５モル％以上は上記アシル基である。ｎは繰り返し数の平均値であり、１５以上５００以下である。 That is, the present invention relates to a modified phenoxy resin represented by the following formula (1) and having a weight average molecular weight of 10,000 to 200,000.

Here, X is a divalent group. Y is an acyl group having 2 to 20 carbon atoms or a hydrogen atom. Z is an acyl group having 2 to 20 carbon atoms or a hydrogen atom, and 5 mol % or more of the acyl group is the above. n is the average number of repetitions, and is 15 to 500.

The present invention also relates to a resin composition containing the above modified phenoxy resin and a curing agent.
The resin composition preferably contains 0.1 to 100 parts by mass of a hardener as a solid content per 100 parts by mass of a solid content of the modified phenoxy resin.

The resin composition contains the modified phenoxy resin, an epoxy resin, and a curing agent, and the mass ratio of the solid content of the modified phenoxy resin to the epoxy resin can be 99/1 to 1/99.
This resin composition preferably contains 0.1 to 100 parts by mass of the hardener as solid content per 100 parts by mass of the total of the solid contents of the modified phenoxy resin and the epoxy resin.

The curing agent to be incorporated in the above resin composition is at least one selected from the group consisting of acrylic ester resins, melamine resins, urea resins, phenolic resins, acid anhydride compounds, amine compounds, imidazole compounds, amide compounds, cationic polymerization initiators, organic phosphines, polyisocyanate compounds, blocked isocyanate compounds, and active ester curing agents.

The present invention also relates to a cured product obtained by curing the above-mentioned resin composition.
The present invention further relates to a laminate for electric/electronic circuits, which is formed using the above resin composition.

ここで、Ｘは２価の基である。Ｙ^１は炭素数２～２０のアシル基である。Ｇはグリシジル基である。ｍは繰り返し数の平均値であり、０以上６以下である。 The present invention also provides a method for producing the above-mentioned modified phenoxy resin, which comprises reacting a bifunctional epoxy resin represented by the following formula (2) with a compound represented by the following formula (3).

Here, X is a divalent group. ^Y1 is an acyl group having 2 to 20 carbon atoms. G is a glycidyl group. m is the average number of repetitions and is 0 to 6.

ここで、Ｌは独立にグリシジル基又は水素原子であり、Ｘは２価の基である。Ｙ^１は炭素数２～２０のアシル基である。ｎは繰り返し数の平均値であり、１５以上５００以下である。 Further, the present invention relates to a method for producing the above-mentioned modified phenoxy resin, which comprises reacting 1.0 mole or more and 2.0 moles or less of an acid anhydride represented by the following formula (5) with 1 mole of an alcoholic hydroxyl group equivalent of the phenoxy resin represented by the following formula (4):

Here, L is independently a glycidyl group or a hydrogen atom, X is a divalent group, ^Y1 is an acyl group having 2 to 20 carbon atoms, and n is the average number of repetitions, which is 15 or more and 500 or less.

According to the present invention, it is possible to provide a modified phenoxy resin having excellent dielectric properties and storage stability. In addition, it is possible to provide a cured product having excellent dielectric properties by using a resin composition using this modified phenoxy resin.

The modified phenoxy resin of the present invention is represented by the above formula (1) and has a weight average molecular weight (Mw) of 10,000 to 200,000.
Here, if Mw is less than 10,000, film formability and mechanical properties (particularly folding resistance) may decrease, which is not preferable. If Mw is more than 200,000, compatibility may decrease, and handling of the resin may become difficult, which is not preferable. Mw is preferably 15,000 to 160,000, more preferably 20,000 to 120,000, and even more preferably 20,000 to 120,000. Mw can be measured by gel permeation chromatography (GPC) as described in the examples.

In formula (1), the terminal group Y is an acyl group or a hydrogen atom, and furthermore, the phenoxy resin has a structure in which some or all of the hydrogen atoms in the hydroxyl groups of ordinary phenoxy resins are replaced with acyl groups. By having the above structure, it has low polarity and excellent dielectric properties. In addition, it has low moisture absorption and good solvent solubility.

The modified phenoxy resin of the present invention can be advantageously obtained by the manufacturing method of the present invention. In this specification, the modified phenoxy resin obtained by the manufacturing method of the present invention may be referred to as the "modified phenoxy resin of the present invention."

In the above formula (1), X represents a divalent group. Preferably, X is a divalent hydrocarbon group or a hydrocarbon group which may have a group such as -O-, -CO-, -S-, -COO-, -SO-, -SO ₂ - in the hydrocarbon chain. Examples of the divalent group include an aromatic skeleton representing a skeleton remaining after removing two hydroxyl groups from an aromatic diol compound, an aliphatic skeleton representing a skeleton remaining after removing two hydroxyl groups from an aliphatic diol compound, and an alicyclic skeleton representing a skeleton remaining after removing two hydroxyl groups from an alicyclic diol compound.
These groups are derived from the residual skeleton obtained by removing two glycidyl groups from a difunctional epoxy resin, the residual skeleton obtained by removing two ester structures from a diester compound, and the residual skeleton obtained by removing two hydroxyl groups from a difunctional phenol compound.

Aromatic skeletons having a structure in which two hydroxyl groups have been removed from an aromatic diol compound specifically include bisphenol types such as bisphenol A, bisphenolacetophenone, 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, and bisphenol cyclohexane, which may be unsubstituted or have an alkyl group having 1 to 10 carbon atoms as a substituent; benzene types such as dihydroxyphenyls such as hydroquinone, resorcin, and catechol, which may be unsubstituted or have an alkyl group having 1 to 10 carbon atoms as a substituent; naphthalene types such as dihydroxynaphthalenes, which may be unsubstituted or have an alkyl group having 1 to 10 carbon atoms as a substituent; biphenyl types such as dihydroxybiphenyls, which may be unsubstituted or have an alkyl group having 1 to 10 carbon atoms as a substituent; bisphenolfluorene and Fluorene-type compounds such as bisphenol fluorenes and bisnaphthol fluorenes, which may be unsubstituted or have an alkyl group having 1 to 10 carbon atoms as a substituent, such as biscresol fluorene; 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, diphenylphosphinylhydroquinone, diphenylphosphinyl-1,4-dioxynaphthalene, 1,4-cyclooctylenephosphinyl-1,4-phenyldiol, 1,5-cyclooctylenephosphinyl-1,4-phenyldiol, and the like, which may be unsubstituted or have an alkyl group, an aryl group, or an aralkyl group having 1 to 10 carbon atoms as a substituent.

Specific examples of the aliphatic skeleton include alkylene glycol skeletons such as ethylene glycol, propylene glycol, and butylene glycol.

Specific examples of the above alicyclic skeleton include hydrogenated bisphenol skeletons such as hydrogenated bisphenol A, hydrogenated bisphenol F, and hydrogenated bisphenol acetophenone.

In the above formula (1), Y is independently an acyl group having 2 to 20 carbon atoms or a hydrogen atom. When Y is an acyl group, an ester group is provided at the end, and when Y is a hydrogen atom, a hydroxyl group is provided at the end. The acyl group is represented by R-CO-, where R is a hydrocarbon group having 1 to 19 carbon atoms. It is advisable to control the proportion of these end groups depending on the application.
The hydrocarbon group having 1 to 19 carbon atoms 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.
The alkyl group having 1 to 12 carbon atoms may be linear, branched, or cyclic, and examples thereof include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, a sec-butyl group, a t-butyl group, an n-pentyl group, an isopentyl group, a neopentyl group, a t-pentyl group, a cyclopentyl group, an n-hexyl group, an isohexyl group, a cyclohexyl group, an n-heptyl group, a cycloheptyl group, a methylcyclohexyl group, an n-octyl group, a cyclooctyl group, an n-nonyl group, a 3,3,5-trimethylcyclohexyl group, an n-decyl group, a cyclodecyl group, an n-undecyl group, an n-dodecyl group, and a cyclododecyl group.
Examples of the aryl group having 6 to 12 carbon atoms include a phenyl group, a tolyl group, an ethylphenyl group, a xylyl group, an n-propylphenyl group, an isopropylphenyl group, a mesityl group, a naphthyl group, and a methylnaphthyl group.
Examples of the aralkyl group having 7 to 13 carbon atoms include a benzyl group, a methylbenzyl group, a dimethylbenzyl group, a trimethylbenzyl group, a phenethyl group, a 2-phenylisopropyl group, and a naphthylmethyl group.
Among these, when Y is an acyl group, the acyl group is more preferably an acyl group having a hydrocarbon group having 1 to 7 carbon atoms, further preferably an acetyl group, a propanoyl group, a butanoyl group, a benzoyl group, or a methylbenzoyl group, and particularly preferably an acetyl group or a benzoyl group. Note that an acetyl group is understood to be an acyl group having 2 carbon atoms.

In formula (1), Z is an acyl group having 2 to 20 carbon atoms (hereinafter, sometimes simply referred to as "acyl group") or a hydrogen atom. At least 5 mol% of Z is an acyl group, and the remainder is a hydrogen atom. The content (mol%) of acyl groups in all Z in formula (1) is also referred to as the acylation rate. The acylation rate is preferably 10 mol% or more, more preferably 50 mol% or more, even more preferably 70 mol% or more, and even more preferably 90 mol% or more. The upper limit is preferably 100%, but substantially 95% is sufficient. The acyl group having 2 to 20 carbon atoms is the same as that exemplified for Y above, and the preferred acyl group is also the same.
When all Z's (100 mol%) are acyl groups, the modified phenoxy resin of the present invention does not contain secondary hydroxyl groups, and the dielectric properties can be further improved. Improvements in solubility and moisture resistance can also be expected. On the other hand, for example, when fine-tuning the adhesion to metals, a portion of Z can be left as hydrogen atoms, so that an appropriate amount of secondary hydroxyl groups can be intentionally present in the modified phenoxy resin of the present invention, as long as it does not significantly affect other physical properties, including moisture resistance.

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

The modified phenoxy resin of the present invention is a resin in which the secondary hydroxyl groups or terminal hydroxyl groups of a normal phenoxy resin are partially or completely acylated, and can be obtained by various methods. For example, the following method is a preferred method for producing the modified phenoxy resin.
(A): A production method in which a bifunctional epoxy resin represented by the above formula (2) is reacted with a diester compound represented by the above formula (3), which may hereinafter be referred to as production method (A).
(B): A production method in which the phenoxy resin represented by the above formula (4) is reacted with an acid component (acylating agent) such as an acid anhydride of an organic acid, an organic acid halide, or an organic acid ester, preferably an acid anhydride of an organic acid, which may hereinafter be referred to as production method (B).
The modified phenoxy resins obtained by the production methods (A) and (B) are the modified phenoxy resins of the present invention.

The production method (A) is a method in which a bifunctional epoxy resin represented by formula (2) is reacted with a diester compound represented by formula (3).
In the above formula (2), G is a glycidyl group, m is the number of repetitions, the average value of which is 0 to 6, preferably 0 to 3.
In formula (3), ^Y1 is an acyl group having 2 to 20 carbon atoms.

X in formula (2) and formula (3) is selected to give X in formula (1).

The bifunctional epoxy resin used in the manufacturing method (A) of the present invention is an epoxy resin represented by the above formula (2), such as an epoxy resin obtained by reacting a bifunctional phenol compound represented by HO-X-OH with epihalohydrin in the presence of an alkali metal compound. Here, X is the same as X in the above formula (1).

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 times by mole, preferably 0.85 to 1.05 times by mole, of an alkali metal compound is used relative to the functional groups in the bifunctional phenolic compound. Less than this amount is not preferred as it results in 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 2 to 10 moles are preferred, and 5 to 8 moles are more preferred. 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.

Epoxidation reactions are usually carried out at temperatures 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. Temperatures of 100°C or less are preferred, and 85°C or less are even more preferred.

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

The diester compound used in the manufacturing method (A) of the present invention can be obtained, for example, by acylation of the above-mentioned bifunctional phenol compound 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 (2) is 0 as the raw material, the modified 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, an appropriate amount of secondary hydroxyl groups can be intentionally made to exist in the modified phenoxy resin, as long as it does not significantly affect other physical properties such as moisture resistance, by using an epoxy resin with an appropriate m number.

The amount of the bifunctional epoxy resin and diester compound used is preferably 1.0 to 1.2 equivalents of ester group per equivalent of epoxy group, more preferably 1.02 to 1.15 equivalents. This equivalent ratio is preferred because it facilitates the progress of high molecular weight in a state in which acyl groups are present at the molecular end. It is also possible to replace a part of the diester compound with the bifunctional phenol compound. This allows the physical properties to be finely adjusted by deliberately allowing an appropriate amount of secondary hydroxyl groups to be present in the modified phenoxy resin.
In the production method (A), a modified phenoxy resin with an increased Mw is produced, and at the same time, 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, imidazole compounds, organic phosphorus compounds, quaternary ammonium salts, etc. 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, 2,4,6-tris(dimethylaminomethyl)phenol, etc.

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 imidazole compounds include, but are not limited to, 2-methylimidazole, 2-ethyl-4-methylimidazole, 2-phenylimidazole, 2-phenyl-4-methylimidazole, 1-benzyl-2-methylimidazole, 1-benzyl-2-phenylimidazole, and the like.

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-dimethylaminopyridine, 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, and 4-(dimethylamino)pyridine, 1,8-diazabicyclo[5,4,0]undecene-7, 1,5-diazabicyclo[4,3,0]nonene-5, and 2-ethyl-4-methylimidazole are 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. Therefore, the nitrogen content derived from the catalyst in the phenoxy resin is preferably 0.5 mass% or less, more preferably 0.3 mass% or less. In addition, the phosphorus content derived from the catalyst 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, and 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, xylene, etc.

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

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, butyrolactone, etc.

Other solvents include, for example, dioxane, dimethyl sulfoxide, sulfolane, etc.

In manufacturing method (A), the solids concentration during the reaction is preferably 35 to 95% by mass. More preferably, it is 50 to 90% by mass, and even more preferably, it is 70 to 90% 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. In addition, when it is necessary to remove the heat of reaction, this is usually done by evaporating, condensing, and refluxing the solvent used by the heat of reaction, indirect cooling, or a combination of these.

Next, the production method (B) of the present invention will be described.
Production method (B) is a method for obtaining a modified phenoxy resin represented by formula (1) having a weight average molecular weight of 10,000 to 200,000, i.e., the modified phenoxy resin of the present invention, by reacting a phenoxy resin represented by formula (4) with 0.05 to 2.0 moles of an acid anhydride represented by formula (5) per mole of an alcoholic hydroxyl group equivalent of the phenoxy resin.

This phenoxy resin can be obtained by a conventional method. Examples of such a method include a method in which bifunctional phenolic compounds are reacted with epihalohydrin in the presence of an alkali metal compound (hereinafter referred to as the "single-step method"), and a method in which bifunctional epoxy resins are reacted with bifunctional phenolic compounds in the presence of a catalyst (hereinafter referred to as the "two-step method"). The phenoxy resin may be obtained by any of the methods, but since it is generally easier to obtain phenoxy resins by the two-step method than by the one-step method, it is preferable to use the two-step method.

The weight average molecular weight and epoxy equivalent of the phenoxy resin 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.

Examples of the bifunctional phenol compound used in the production of the one-stage method and the two-stage method 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; 1,1-bi-2-naphthol, catechol, resorcin, hydroquinone, and dihydroxynaphthalene.
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, 0.98 to 1.0 moles, preferably 0.985 to 0.997 moles, more preferably 0.99 to 0.995 moles of epihalohydrin are reacted in a non-reactive solvent in the presence of an alkali metal compound with 1 mole of bifunctional phenolic compounds, 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. 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 the above formula (2) used in the production method (A) of the present invention.

This reaction can be carried out under normal pressure or reduced pressure. The reaction temperature is usually 20 to 200°C, more preferably 30 to 170°C, even more preferably 40 to 150°C, and particularly preferably 50 to 100°C, for reactions under normal pressure. The reaction temperature is preferably 20 to 100°C, more preferably 30 to 90°C, and even more preferably 35 to 80°C, for reactions under reduced pressure. 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, the same bifunctional epoxy resin as that represented by the above formula (2) used in the production process (A) of the present invention is used.

Examples of bifunctional epoxy resins that are used as raw materials in the two-stage process include bisphenol type epoxy resins such as bisphenol A type epoxy resins, bisphenol F type epoxy resins, bisphenol S type epoxy resins, bisphenolacetophenone type epoxy resins, diphenyl sulfide type epoxy resins, and diphenyl ether type epoxy resins, biphenol type epoxy resins, diphenyldicyclopentadiene type epoxy resins, alkylene glycol type epoxy resins, naphthalene type epoxy resins, benzene type epoxy resins, and aliphatic cyclic epoxy resins. These epoxy resins may be substituted with non-detrimental substituents such as alkyl groups and aryl groups. Multiple types of these epoxy resins may be used in combination.

The amount of bifunctional epoxy resin used is preferably 0.85 to 1.00 mol, more preferably 0.90 to 1.00 mol, even more preferably 0.95 to 1.00 mol, and particularly preferably 0.97 to 0.99 mol, per 1.00 mol of bifunctional phenolic compound. If the amount of bifunctional epoxy resin used is within this range, the molecular weight of the resulting phenoxy resin is sufficiently extended, which is preferable.

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 the above formula (2) 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. When 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 modified phenoxy resin of the present invention can be obtained by acylation of the hydroxyl groups in the phenoxy resin represented by the above formula (4) obtained in this manner. Acylation can be achieved not only by direct esterification but also by methods such as transesterification.

As the acid component used in the above acylation, 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 can be used. Preferably, the acid anhydride is represented by formula (5).

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 rinsing with water after esterification and they avoid the inclusion of halogens, which are undesirable in electrical material applications.

The charge ratio of the acid components, such as the organic acids, acid anhydrides of organic acids, halides of organic acids, and esters of organic acids, used to esterify the hydroxyl groups of the phenoxy resin, when reacting with the phenoxy resin may be the same as the desired esterification ratio, or, if the reactivity is low, the acid components may be charged in excess relative to the hydroxyl groups, and after reacting to the desired esterification rate, the unreacted acid components may be removed.

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 anhydride is used for esterification, the resulting acid can be removed by any of the following methods, or a combination of these: 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. When removing an acid with a lower boiling point than the reaction solvent, it is preferable to remove it by distillation.

When phenoxy resin is esterified by ester exchange, it is usually desirable to carry out the esterification under a nitrogen atmosphere while dealcoholizing 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, sulfonic acid, or basic catalyst such as lithium hydroxide, sodium hydroxide, etc.

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. 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 containing at least the modified phenoxy resin of the present invention and a curing agent, but preferably contains an epoxy resin. In addition, various additives such as inorganic fillers, coupling agents, and antioxidants can be appropriately blended into the resin composition of the present invention as necessary. The resin composition of the present invention gives a cured product that fully satisfies the various physical properties required for various applications.

A resin composition can be prepared by blending a curing agent with the modified phenoxy resin of the present invention. In the present invention, the curing agent refers to a substance that contributes to the crosslinking reaction and/or chain extension reaction with the modified phenoxy resin. In the present invention, even substances that are normally called "curing accelerators" are considered to be curing agents as long as they contribute to the crosslinking reaction and/or chain extension reaction of the modified phenoxy resin.

The content of the curing agent in the resin composition of the present invention is preferably 0.1 to 100 parts by mass in terms of solid content per 100 parts by mass of the solid content of the modified phenoxy resin. It is more preferably 80 parts by mass or less, and even more preferably 60 parts by mass or less.

In the resin composition of the present invention, when an epoxy resin described below is contained, the weight ratio of the solid contents of the modified phenoxy resin and the epoxy resin is 99/1 to 1/99. In the present invention, "solid contents" refers to components excluding the solvent, and includes not only solid modified phenoxy resins and epoxy resins, but also semi-solid and viscous liquid substances. In addition, "resin components" refers to the sum of the modified phenoxy resin of the present invention and the epoxy resin described below.

The curing agent used in the resin composition of the present invention includes those having two or more functional groups that react with the residual hydroxyl groups of the modified phenoxy resin. Examples include acid anhydride-based curing agents, isocyanate-based curing agents, and blocked isocyanate-based curing agents. These curing agents may be used alone or in combination of two or more types.

The resin composition of the present invention may contain an epoxy resin and a curing agent. By using an epoxy resin, it is possible to compensate for insufficient physical properties and improve various physical properties. As the epoxy resin, it is preferable that the epoxy resin has two or more epoxy groups in the molecule, and more preferably an epoxy resin having three or more epoxy groups. For example, polyglycidyl ether compounds, polyglycidyl amine compounds, polyglycidyl ester compounds, alicyclic epoxy compounds, other modified epoxy resins, etc. may be mentioned. These epoxy resins may be used alone, or two or more types of epoxy resins of the same system may be used in combination, or epoxy resins of different systems may be used in combination.

Examples of polyglycidyl ether compounds that can be used include various epoxy resins such as bisphenol A type epoxy resins, bisphenol F type epoxy resins, bisphenol S type epoxy resins, bisphenol AF type epoxy resins, bisphenol Z type epoxy resins, bisphenol fluorene type epoxy resins, diphenyl sulfide type epoxy resins, diphenyl ether type epoxy resins, naphthalene type epoxy resins, hydroquinone type epoxy resins, resorcinol type epoxy resins, phenol novolac type epoxy resins, cresol novolac type epoxy resins, alkyl novolac type epoxy resins, styrenated phenol novolac type epoxy resins, bisphenol novolac type epoxy resins, naphthol novolac type epoxy resins, phenol aralkyl type epoxy resins, β-naphthol aralkyl type epoxy resins, naphthalenediol aralkyl type epoxy resins, α-naphthol aralkyl type epoxy resins, biphenyl aralkyl phenol type epoxy resins, biphenyl type epoxy resins, triphenylmethane type epoxy resins, dicyclopentadiene type epoxy resins, alkylene glycol type epoxy resins, and aliphatic cyclic epoxy resins.

Examples of polyglycidylamine compounds include diaminodiphenylmethane type epoxy resins, metaxylenediamine type epoxy resins, 1,3-bisaminomethylcyclohexane type epoxy resins, isocyanurate type epoxy resins, aniline type epoxy resins, hydantoin type epoxy resins, aminophenol type epoxy resins, etc.

Examples of polyglycidyl ester compounds include dimer acid type epoxy resins, hexahydrophthalic acid type epoxy resins, trimellitic acid type epoxy resins, etc.

Examples of alicyclic epoxy compounds include aliphatic cyclic epoxy resins such as Celloxide 2021 (manufactured by Daicel Chemical Industries, Ltd.).

Other modified epoxy resins include, for example, urethane-modified epoxy resins, oxazolidone ring-containing epoxy resins, epoxy-modified polybutadiene rubber derivatives, carboxyl-terminated butadiene nitrile rubber (CTBN)-modified epoxy resins, polyvinylarene polyoxides (e.g., divinylbenzene dioxide, trivinylnaphthalene trioxide, etc.), phenoxy resins, etc.

The curing agent used in the resin composition of the present invention containing an epoxy resin is not particularly limited, and any agent generally known as an epoxy resin curing agent can be used. Examples of curing agents other than those mentioned above include phenol-based curing agents, amide-based curing agents, imidazole-based compounds, active ester-based curing agents, amine-based curing agents, and hydrazide-based curing agents. Preferred curing agents from the viewpoint of improving heat resistance include phenol-based curing agents, active ester-based curing agents, amide-based curing agents, and imidazole-based compounds, and preferred curing agents from the viewpoint of improving water resistance include phenol-based curing agents and active ester-based curing agents. These curing agents may be used alone or in combination of two or more types.

Examples of phenol-based hardeners include bisphenol A, bisphenol F, 4,4'-dihydroxydiphenylmethane, 4,4'-dihydroxydiphenyl ether, 1,4-bis(4-hydroxyphenoxy)benzene, 1,3-bis(4-hydroxyphenoxy)benzene, 4,4'-dihydroxydiphenyl sulfide, 4,4'-dihydroxydiphenyl ketone, 4,4'-dihydroxydiphenyl sulfone, 4,4'-dihydroxybiphenyl, 2,2'-dihydroxybiphenyl, 10-(2,5-dihydroxyphenyl)-10H-9-oxa-10-phosphaphenanthrene-10-oxide, phenol novolac, bisphenol A novolac, o-cresol novolac, m-cresol novolac, p-cresol novolac, xylenol novolac, poly-p-hydroxystyrene, hydroquinone, resorcinol, catechol, t-butylcatechol, t-Butyl hydroquinone, fluoroglycinol, pyrogallol, t-butyl pyrogallol, allylated pyrogallol, polyallylated pyrogallol, 1,2,4-benzenetriol, 2,3,4-trihydroxybenzophenone, 1,2-dihydroxynaphthalene, 1,3-dihydroxynaphthalene, 1,4-dihydroxynaphthalene, 1,5-dihydroxynaphthalene, 1,6-dihydroxynaphthalene, 1,7-dihydroxynaphthalene, 1,8-dihydroxynaphthalene, 2,3-dihydroxynaphthalene, 2,4-dihydroxynaphthalene, 2,5-dihydroxynaphthalene, 2,6-dihydroxynaphthalene, 2,7-dihydroxynaphthalene, 2,8-dihydroxynaphthalene, allylated products or polyallylated products of the above dihydroxynaphthalenes, allylated bisphenol A, allylated bisphenol F, allylated phenol novolak, allylated pyrogallol, and the like.

Examples of amide-based curing agents include dicyandiamide and its derivatives, polyamide resins, etc.

Examples of imidazole compounds include 2-phenylimidazole, 2-ethyl-4(5)-methylimidazole, 2-phenyl-4-methylimidazole, 1-benzyl-2-methylimidazole, 1-benzyl-2-phenylimidazole, 1-cyanoethyl-2-undecylimidazole, 1-cyano-2-phenylimidazole, 1-cyanoethyl-2-undecylimidazole trimellitate, 1-cyanoethyl-2-phenylimidazolium trimellitate, 2,4-diamino-6-[2'-methylimidazole Examples of the imidazole-based compound include 2,4-diamino-6-[2'-ethyl-4'-methylimidazolyl-(1')]-ethyl-s-triazine, 2,4-diamino-6-[2'-ethyl-4'-methylimidazolyl-(1')]-ethyl-s-triazine, 2,4-diamino-6-[2'-methylimidazolyl-(1')]-ethyl-s-triazine isocyanuric acid adduct, 2-phenylimidazole isocyanuric acid adduct, 2-phenyl-4,5-dihydroxymethylimidazole, 2-phenyl-4-methyl-5-hydroxymethylimidazole, and an adduct of an epoxy resin with the imidazole-based compound. Note that since the imidazole-based compound has catalytic activity, it can generally be classified as a curing accelerator, which will be described later, but in the present invention, it is classified as a curing agent.

Examples of active ester-based curing agents include reaction products of polyfunctional phenolic compounds and aromatic carboxylic acids, as described in Japanese Patent No. 5,152,445. Commercially available products include Epiclon HPC-8000-65T (manufactured by DIC Corporation), but are not limited to these.

Other curing agents that can be used in the resin composition of the present invention include, for example, amine-based curing agents, tertiary amines, organic phosphines, phosphonium salts, tetraphenylboron salts, organic acid dihydrazides, boron halide amine complexes, polymercaptan-based curing agents, etc. These other curing agents may be used alone or in any combination and ratio of two or more.

When the modified phenoxy resin and epoxy resin of the present invention are used in the resin composition of the present invention, the amount of epoxy resin in the total components of the modified phenoxy resin and epoxy resin as solids is preferably 1 to 99 mass%, more preferably 5 to 97 mass%, even more preferably 10 to 95 mass%, and even more preferably 10 to 90 mass%. By having the epoxy resin in the above amount, it is possible to improve the heat resistance and mechanical strength when a cured product made from the resin composition of the present invention is obtained.

The resin composition of the present invention may contain a solvent or reactive diluent to appropriately adjust the viscosity of the resin composition when handling the composition to form a coating film. In the resin composition of the present invention, the solvent or reactive diluent is used to ensure the ease of handling and workability in molding the resin composition, and there is no particular limit to the amount used. In the present invention, the term "solvent" and the aforementioned term "solvent" are used separately depending on the form of use, but the same or different types of solvents may be used independently.

Examples of solvents that may be contained in the resin composition of the present invention include ketones such as acetone, methyl ethyl ketone (MEK), methyl isobutyl ketone, and cyclohexanone, esters such as ethyl acetate, ethers such as ethylene glycol monomethyl ether, amides such as N,N-dimethylformamide and N,N-dimethylacetamide, alcohols such as methanol and ethanol, alkanes such as hexane and cyclohexane, and aromatics such as toluene and xylene. The above-mentioned solvents may be used alone or in any combination and ratio of two or more.

Examples of reactive diluents include monofunctional glycidyl ethers such as allyl glycidyl ether, bifunctional glycidyl ethers such as propylene glycol diglycidyl ether, polyfunctional glycidyl ethers such as trimethylolpropane polyglycidyl ether, glycidyl esters, and glycidyl amines.

These solvents or reactive diluents 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.

In the resin composition of the present invention, a curing accelerator (excluding those included in the "curing agent") can be used as necessary. Examples of the curing accelerator include imidazole compounds, tertiary amines, phosphorus compounds such as phosphines, metal compounds, Lewis acids, amine complex salts, etc. These curing accelerators may be used alone or in combination of two or more types.

The amount of the curing accelerator may be selected appropriately depending on the intended use, but 0.01 to 15 parts by mass is used as necessary, with 0.01 to 10 parts by mass being preferred, 0.05 to 8 parts by mass being more preferred, and 0.1 to 5 parts by mass being even more preferred, per 100 parts by mass of the epoxy resin component in the resin composition. By using a curing accelerator, it is possible to lower the curing temperature and shorten the curing time.

In the 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 may be used alone, or two or more of the same type of flame retardants may be used in combination, or different types of flame retardants may be used in combination.

The resin composition of the present invention may contain components other than those listed above (sometimes referred to as "other components" in the present invention) for the purpose of further improving its functionality. Such other components include fillers, thermoplastic resins, thermosetting resins, photocurable resins, ultraviolet protection agents, antioxidants, coupling agents, plasticizers, fluxes, thixotropic agents, smoothing agents, colorants, pigments, dispersants, emulsifiers, elasticity reducing agents, release agents, defoamers, ion trapping agents, etc.

Examples of fillers include inorganic fillers such as fused silica, crystalline silica, alumina, silicon nitride, boron nitride, aluminum nitride, aluminum hydroxide, calcium hydroxide, magnesium hydroxide, boehmite, talc, mica, clay, calcium carbonate, magnesium carbonate, barium carbonate, zinc oxide, titanium oxide, magnesium oxide, magnesium silicate, calcium silicate, zirconium silicate, barium sulfate, and carbon; fibrous fillers such as carbon fiber, glass fiber, alumina fiber, silica alumina fiber, silicon carbide fiber, polyester fiber, cellulose fiber, aramid fiber, and ceramic fiber; and fine particle rubber.

The resin composition of the present invention may be used in combination with a thermoplastic resin other than the phenoxy resin of the present invention. Examples of thermoplastic resins include phenoxy resins other than those of the present invention, polyurethane resins, polyester resins, polyethylene resins, polypropylene resins, polystyrene resins, ABS resins, AS resins, vinyl chloride resins, polyvinyl acetate resins, polymethyl methacrylate resins, polycarbonate resins, polyacetal resins, cyclic polyolefin resins, polyamide resins, thermoplastic polyimide resins, polyamideimide resins, polytetrafluoroethylene resins, polyetherimide resins, polyphenylene ether resins, modified polyphenylene ether resins, polyethersulfone resins, polysulfone resins, polyetheretherketone resins, polyphenylene sulfide resins, polyvinyl formal resins, etc. In terms of compatibility, phenoxy resins other than those of the present invention are preferred, and polyphenylene ether resins and modified polyphenylene ether resins are preferred in terms of low dielectric properties.

Other components include organic pigments such as quinacridone, azo, and phthalocyanine pigments, inorganic pigments such as titanium oxide, metal foil pigments, and rust-preventive pigments, ultraviolet absorbers such as hindered amines, benzotriazoles, and benzophenones, antioxidants such as hindered phenols, phosphorus, sulfur, and hydrazides, release agents such as stearic acid, palmitic acid, zinc stearate, and calcium stearate, and additives such as leveling agents, rheology control agents, pigment dispersants, anti-cision agents, and defoamers. The amount of these other components to be added is preferably in the 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 is obtained by uniformly mixing the above components. The resin composition containing the phenoxy resin, the curing agent, and further various components as necessary can be easily cured 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. "Cure" here means intentionally curing the resin composition with heat and/or light, etc., and the degree of curing may be controlled according to the desired physical properties and applications. The degree of progress may be completely cured or semi-cured, and is not particularly limited, but the reaction rate of the curing reaction between the epoxy group and the curing agent is usually 5 to 95%.

Methods for obtaining a cured product from the resin composition of the present invention include casting, injection, potting, dipping, drip coating, transfer molding, compression molding, etc., and laminating the resin in the form of a resin sheet, copper foil with resin, prepreg, etc., and curing it under heat and pressure to form a laminate. 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. By performing such secondary and tertiary heating, it is possible to reduce curing defects. When producing a semi-cured resin product such as a resin sheet, copper foil with resin, or prepreg, the curing reaction of the resin composition is usually allowed to proceed to a degree that the shape can be maintained by heating, etc. When the resin composition contains a solvent, most of the solvent is usually removed by techniques such as heating, reducing pressure, and air drying, but 5% by mass or less of the solvent may remain in the semi-cured resin product.

The prepreg obtained using the resin composition of the present invention will be described. As the sheet-like substrate, inorganic fibers such as glass, or woven or nonwoven fabrics of organic fibers such as polyester, polyamine, polyacrylic, polyimide, Kevlar, and cellulose can be used, but are not limited thereto. The method for producing a prepreg from the resin composition and substrate of the present invention 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 can be heated and dried for 1 to 40 minutes, for example. Here, the amount of resin in the prepreg is preferably 30 to 80% by mass of resin.

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 this 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 so that the resin composition is cured, but if the pressure is too low, air bubbles may remain inside the obtained laminate, which may deteriorate the electrical properties, so it is desirable to pressurize under conditions that satisfy the moldability. For example, the temperature can be set to 160 to 220°C, the pressure to 49 to 490 N/cm ² (5 to 50 kgf/cm ² ), and the heating time to 40 to 240 minutes.

Furthermore, a multilayer board can be made by using the single-layer 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, subtractive method, etc., and the surface of the formed circuit is treated with an acid solution for blackening to obtain the inner layer material. An insulating layer is formed on one or both circuit-forming surfaces of this inner layer material using a prepreg or 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 a plurality of 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 thus formed 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 the insulating layer with 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 the insulating layer, and the metal foil on the outside is formed as the 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) and number average molecular weight (Mn):
It was obtained by GPC measurement. Specifically, a main body HLC8320GPC (manufactured by Tosoh Corporation) equipped with columns (TSKgel SuperH-H, SuperHR2000, 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 1.0 mL / min, and the detector was a differential refractive index detector. The measurement sample was 0.1 g in solid content dissolved in 10 mL of THF and filtered with a 0.45 μm microfilter, and 50 μL was used. Mw and Mn were calculated from the calibration curve obtained from standard polystyrene ("PS-oligomer kit" manufactured by Tosoh Corporation). 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 K 7235. The drying temperature was 200° C., and the drying time was 60 minutes.

(3) Dielectric properties:
The dielectric loss tangent was evaluated by measuring at 1 GHz by a cavity resonator perturbation method. Specifically, the measurement was performed using a PNA network analyzer N5230A (manufactured by Agilent Technologies, Inc.) and a cavity resonator CP431 (manufactured by Kanto Electronics Application Development Co., Ltd.) under a measurement environment of room temperature 23°C and humidity 50% RH, using a test piece with a width of 1.5 mm, length of 80 mm, and thickness of 150 μm.

(4) Storage stability:
15 parts of 2-ethyl-4-methylimidazole (Curesol 2E4MZ, manufactured by Shikoku Chemical Industry Co., Ltd.) was mixed with 100 parts of the phenoxy resin varnish obtained in the following Examples and Comparative Examples to prepare a resin composition varnish for evaluating storage stability. The condition after leaving the varnish at 25°C for 24 hours was visually observed, and the storage stability was evaluated according to the following criteria.
○: No gelation and fluidity ×: Gelled and no longer fluid

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

[Bifunctional epoxy resin]
A1: Bisphenol A type epoxy resin (manufactured by Nippon Steel Chemical & Material Co., Ltd., YD-128, epoxy equivalent 186, m ≒ 0.11)
A2: Fluorene-type epoxy resin (manufactured by Nippon Steel Chemical & Material Co., Ltd., ESF-300, epoxy equivalent 250, m≒0.08)
A3: Hydroquinone type epoxy resin (manufactured by Nippon Steel Chemical & Material Co., Ltd., ZX-1027, epoxy equivalent 131, m ≒ 0.18)
A4: Biphenyl type epoxy resin (manufactured by Mitsubishi Chemical Corporation, YX-4000, epoxy equivalent 196, m≒0.13)
A5: Naphthalene type epoxy resin (DIC Corporation, Epicron HP4032D, epoxy equivalent 142, m≒0.07)
Here, m has the same meaning as m in the above formula (2).

[Diester compounds]
B1: 4,4'-diacetoxybiphenyl (Tokyo Chemical Industry Co., Ltd., active equivalent = 135)
B2: 2,6-diacetoxynaphthalene (Tokyo Chemical Industry Co., Ltd., active equivalent = 122)
B3: Phosphorus-containing diester compound obtained in Synthesis Example 1

[Bifunctional phenol compound]
C1: 10-(2,5-dihydroxyphenyl)-9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (manufactured by Sanko Kagaku Co., Ltd., HCA-HQ, hydroxyl equivalent = 162)
C2: Bisphenol A (manufactured by Nippon Steel Chemical & Material Co., Ltd., hydroxyl equivalent = 114)

[catalyst]
D1: 4-Dimethylaminopyridine (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.)
D2: 2-ethyl-4-methylimidazole (Curesol 2E4MZ, manufactured by Shikoku Chemical Industry Co., Ltd.)

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

[Acid anhydride]
E1: Acetic anhydride (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.)
E2: Benzoic anhydride (Tokyo Chemical Industry Co., Ltd.)

[Curing agent]
H1: Phenol novolak resin (manufactured by Aica Kogyo Co., Ltd., Shounol BRG-557, hydroxyl equivalent: 105)
H2: 2-ethyl-4-methylimidazole (Curesol 2E4MZ, manufactured by Shikoku Chemical Industry Co., Ltd.)

Synthesis Example 1
A glass reaction vessel equipped with a stirrer, a thermometer, a nitrogen gas introduction device, a cooling tube, and a dropping device was charged with 100 parts of C1, 315 parts of E1, 0.05 parts of dibutyltin maleate, and 186 parts of acetic acid at room temperature, and the mixture was heated to 110°C while stirring under nitrogen gas flow, and reacted for 2 hours. Thereafter, the mixture was dried under reduced pressure at 130°C and 1.3 kPa (10 torr) for 3 hours, and 98 parts of B3 was obtained. The active equivalent was 204.

Example 1
A glass reaction vessel equipped with a stirrer, a thermometer, a nitrogen gas inlet, a cooling tube, and a dropping device was charged with 100 parts of A1, 76 parts of B1, and 44 parts of S1 as a reaction solvent at room temperature, and the mixture was heated to 130°C while stirring under nitrogen gas flow, and 0.2 parts of D1 was added as a catalyst, and then the mixture was heated to 145°C and reacted at the same temperature for 7 hours. 44 parts of S1 and 176 parts of S2 were used as dilution solvents to dilute and mix, and a modified phenoxy resin varnish (R1) with a non-volatile content of 40% was obtained.

Examples 2 to 10, Comparative Examples 1 to 2
A modified phenoxy resin varnish (a phenoxy resin varnish in Comparative Example 2) was obtained by the same procedure as in Example 1 according to the amount (parts) of each raw material shown in Tables 1 and 2. In addition, the "equivalent ratio" in the tables indicates the equivalent ratio (functional group ratio) of the total of the functional groups of the diester compound and the hydroxyl groups of the bifunctional phenol compound to the epoxy groups of the bifunctional epoxy resin.

Example 11
100 parts (40 parts in solid content) of the phenoxy resin varnish (RH2) obtained in Comparative Example 2 and 600 parts of S1 were mixed, and the temperature was raised to 100°C, after which 16 parts of E1 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. 23 parts of S1 and 45 parts of S2 were added to the obtained phenoxy resin and dissolved uniformly to obtain a modified phenoxy resin varnish (R11) with a non-volatile content of 40%.

Example 12
The same procedure as in Example 11 was repeated except that 36 parts of E2 were used instead of E1, and 27 parts of S1 and 54 parts of S2 were used as dilution solvents, to obtain a modified phenoxy resin varnish (R12).

The resin varnishes R1 to R12 and RH1 to RH2 obtained in Examples 1 to 12 and Comparative Examples 1 to 3 were applied to an iron plate so that the film thickness after drying would be 150 μm, and then dried at 180° C. for 1 hour using a dryer to obtain a resin film.
The Mw and storage stability of the phenoxy resin varnish and the dielectric properties of the resin film were measured. The results are shown in Table 3. In the table, the "acylation rate" indicates the content (mol%) of acyl groups in the total Z. The examples using resin varnishes RH1 to RH2 are comparative examples.

Examples 13 to 17, Comparative Example 3
A resin composition was obtained by blending 30 parts (12 parts solids) of the modified phenoxy resin varnish (R1-5, RH1) obtained in Examples 1-5 and Comparative Example 1, 2 parts of A5 as an epoxy resin, 2.5 parts of H1 in a 50% MEK solution as a curing agent, and 0.6 parts of H2 in a 20% MEK solution as a curing agent. The resin composition was then applied to an iron plate so that the film thickness after drying would be 150 μm, and the mixture was dried at 180° C. for 1 hour in a dryer to obtain a film-like cured product. The dielectric properties were measured, and the results are shown in Table 4.

As can be seen from Table 3, the modified phenoxy resins of the present invention shown in Examples 1 to 12 have excellent dielectric properties and storage stability. In addition, as can be seen from Table 4, the cured products made from the resin compositions of the present invention also have excellent dielectric properties.

Possible industrial applications

The modified 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 of the present invention and a resin composition containing the same 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 (10)

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

Here, X is a divalent group (excluding the cases where X contains a group represented by the following formula (I) or formula (II)) . Y is an acyl group having 2 to 20 carbon atoms or a hydrogen atom. Z is an acyl group having 2 to 20 carbon atoms or a hydrogen atom, and 5 mol % or more of Z are the above acyl groups. n is the average number of repetitions, and is 15 to 500.

In formula (I) and formula (II), R is independently a group selected from the group consisting of 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, an aralkyl group having 7 to 13 carbon atoms, an aryloxy group having 6 to 12 carbon atoms, an aralkyloxy group having 7 to 13 carbon atoms, an alkenyl group having 2 to 12 carbon atoms, and an alkynyl group having 2 to 12 carbon atoms; i is an integer from 0 to 4, and j is an integer from 0 to 6. A resin composition comprising the modified phenoxy resin according to claim 1 and a curing agent. The resin composition according to claim 2, which contains 0.1 to 100 parts by mass of the hardener as solid content per 100 parts by mass of the solid content of the modified phenoxy resin. The resin composition according to claim 2, which contains the modified phenoxy resin according to claim 1, an epoxy resin, and a curing agent, and the mass ratio of the solid content of the modified phenoxy resin to the epoxy resin is 99/1 to 1/99. The resin composition according to claim 4, which contains 0.1 to 100 parts by mass of the hardener as solid content per 100 parts by mass of the total solid content of the modified phenoxy resin and the epoxy resin. The resin composition according to any one of claims 2 to 5, wherein the curing agent is at least one selected from the group consisting of acrylic ester resins, melamine resins, urea resins, phenolic resins, acid anhydride compounds, amine compounds, imidazole compounds, amide compounds, cationic polymerization initiators, organic phosphines, polyisocyanate compounds, blocked isocyanate compounds, and active ester curing agents. A cured product obtained by curing the resin composition according to any one of claims 2 to 6. A laminate for electrical/electronic circuits made using the resin composition according to any one of claims 2 to 6. A method for producing a modified phenoxy resin, comprising reacting a bifunctional epoxy resin represented by the following formula (2) with a compound represented by the following formula (3) to obtain a modified phenoxy resin represented by the following formula (1) having a weight average molecular weight of 10,000 to 200,000.

Here, X is a divalent group (except when X contains a group represented by formula (I) or formula (II) below) . G is a glycidyl group. ^Y1 is an acyl group having 2 to 20 carbon atoms. Y is an acyl group having 2 to 20 carbon atoms or a hydrogen atom. Z is an acyl group having 2 to 20 carbon atoms or a hydrogen atom, and 5 mol % or more of Z are the above acyl groups. m is the average number of repetitions and is 0 to 6. n is the average number of repetitions and is 15 to 500.

In formula (I) and formula (II), R is independently a group selected from the group consisting of 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, an aralkyl group having 7 to 13 carbon atoms, an aryloxy group having 6 to 12 carbon atoms, an aralkyloxy group having 7 to 13 carbon atoms, an alkenyl group having 2 to 12 carbon atoms, and an alkynyl group having 2 to 12 carbon atoms; i is an integer from 0 to 4, and j is an integer from 0 to 6. A method for producing a modified phenoxy resin, comprising reacting 1.0 mole or more and 2.0 moles or less of an acid anhydride represented by the following formula (5) with 1 mole of an alcoholic hydroxyl group of a phenoxy resin represented by the following formula (4) to obtain a modified phenoxy resin represented by the following formula (1) having a weight average molecular weight of 10,000 to 200,000.

Here, L is independently a glycidyl group or a hydrogen atom, and X is a divalent group. ^Y1 is an acyl group having 2 to 20 carbon atoms. Y is an acyl group having 2 to 20 carbon atoms or a hydrogen atom. Z is an acyl group having 2 to 20 carbon atoms or a hydrogen atom, and 5 mol % or more of Z is the above acyl group. n is the average number of repetitions, and is 15 to 500.