JP5686770B2 - Epoxy resin composition - Google Patents

Description

The present invention is used for insulating materials for electrical and electronic parts including those for high-reliability semiconductor encapsulation, as well as various types including laminated boards (printed wiring boards, build-up boards), CFRP (carbon fiber reinforced plastic), and optical materials. The present invention relates to an epoxy resin composition useful for composite materials, adhesives, paints and the like.

Epoxy resin compositions are widely used in the fields of electrical and electronic parts, structural materials, adhesives, paints, etc. due to their workability and excellent electrical properties, heat resistance, adhesion, moisture resistance (water resistance), etc. It has been.

However, in recent years, with the development in the electric and electronic fields, the resin composition is highly purified, moisture resistance, adhesion, dielectric properties, low viscosity for high filler filling, and short molding cycle. There is a need for further improvements in various properties such as increased reactivity. Further, as a structural material, there is a demand for a material that is lightweight and has excellent mechanical properties in applications such as aerospace materials and leisure / sports equipment. Furthermore, in recent years, halogen-based epoxy resins and antimony trioxide have been widely used as flame retardants, especially as flame retardants for electrical and electronic parts. Products that use these are toxic substances such as dioxins due to inappropriate treatment after disposal. It has been pointed out that it contributes to the occurrence of As one of the methods for solving the above problem, the use of a phenol resin represented by the following formula (1) or an epoxidized product thereof is described in Patent Document 1, Patent Document 2, and the like. However, since the resin having this structure has strong crystallinity, crystals are precipitated and the melt viscosity is increased depending on the state of taking out the resin during production and the storage state. In addition, when dissolved in a solvent, crystals were precipitated and precipitated, which was extremely problematic for use as a composition.

JP-A-11-140277 JP-A-11-140166

An object of the present invention is to suppress the precipitation of crystals, and to improve the workability and quality control during the manufacture thereof, so that insulating materials for electrical and electronic parts (such as highly reliable semiconductor sealing materials) and laminated boards (prints) Wiring board, build-up board, etc.) and various composite materials including CFRP, adhesives, paints, and the like.

(式中ｎは繰り返し数を表し、１〜２０の整数を示す。)
で表されるフェノール樹脂であって、水酸基に対してｏ位にメチレン基が結合しているベンゼン環の総モル数（ｏ−配位数）と水酸基に対してｐ位にメチレン基が結合しているベンゼン環の総モル数（ｐ−配位数）が、ｏ−配位数／ｐ−配位数≧１．５×Ｖ＋１．２（Ｖは１５０℃における溶融粘度で、単位はＰａ・ｓを示す）であるフェノール樹脂とエピハロヒドリンとを反応させて得られるエポキシ樹脂
（ｂ）硬化剤
及び
（ｃ）溶剤
を含有することを特徴とするエポキシ樹脂組成物
（２）式（１）で表されるフェノール樹脂において、下記式（２）、式(３) The present inventors have completed the present invention as a result of intensive studies in order to solve the above problems. That is, the present invention
(1)
(A) Formula (1) obtained by reacting 4,4′-bischloromethylbiphenyl and phenol in the presence of a basic substance

(In the formula, n represents the number of repetitions and represents an integer of 1 to 20.)
Wherein the total number of moles of the benzene ring in which the methylene group is bonded to the o position with respect to the hydroxyl group (o-coordination number) and the methylene group is bonded to the p position with respect to the hydroxyl group. The total number of moles of benzene rings (p-coordination number) is o-coordination number / p-coordination number ≧ 1.5 × V + 1.2 (V is the melt viscosity at 150 ° C., the unit is Pa · s), an epoxy resin obtained by reacting a phenol resin with epihalohydrin (b), a curing agent and (c) a solvent, and an epoxy resin composition (2) represented by formula (1) In the phenol resin used, the following formula (2), formula (3)

で表される成分の存在割合ｏｏ／ｐｐ（ｏｏは式(３)の化合物の総モル数、ｐｐは式(２)の化合物の総モル数）が、−０．０３×Ｄ＋２．７（Ｄは、フェノール樹脂中のｎ＝１の分子の含有割合（重量％）を示す）以上であるフェノール樹脂を使用する上記（１）記載のエポキシ樹脂組成物
に関する。

The abundance ratio of the component represented by oo / pp (oo is the total number of moles of the compound of formula (3), pp is the total number of moles of the compound of formula (2)) is -0.03 × D + 2.7 (D Relates to the epoxy resin composition according to the above (1), which uses a phenol resin which is equal to or higher than the content ratio (% by weight) of the molecule of n = 1 in the phenol resin.

In the epoxy resin composition of the present invention, since precipitation of crystals of the epoxy resin component hardly occurs, it is possible to prevent a decrease in performance after long-term storage.

Hereinafter, an epoxy resin as an essential component of the epoxy resin composition of the present invention and a phenol resin (hereinafter referred to as a phenol resin of the present invention) as a raw material of the epoxy resin (hereinafter referred to as an epoxy resin of the present invention) will be described. The phenol resin represented by the formula (1) is generally synthesized by a method as described in Japanese Patent No. 3122834 and Japanese Patent Application Laid-Open No. 2001-40053. When the resin of formula (1) obtained by this method is gradually cooled and solidified from the molten state at the time of production, the crystal tends to precipitate, and the melt viscosity is higher than that of the rapidly cooled and solidified resin. When melt viscosity becomes high, when used for a semiconductor sealing material, for example, fluidity is lowered. Moreover, when the epoxy resin which epoxidized Formula (1) is stored in the state melt | dissolved in the solvent, a crystal | crystallization will precipitate. In particular, when used in a liquid epoxy resin composition, the organic components in the composition were in a uniform state at the time of manufacture, but crystals were precipitated during refrigerated storage, resulting in uneven distribution of the components. Consequently, problems such as poor curing and the inability to obtain the cured physical properties as designed occur. According to the study by the present inventors, such crystallization is more prominent in the structure of the formula (1) as the positional relationship of the bond between the methylene group and the hydroxyl group increases as the ratio of para is higher. It was confirmed that this was remarkable when the amount of the compound 2) was large. For this reason, in the structure of the formula (1), if the positional relationship of the bond between the methylene group and the hydroxyl group is para, or if the component of the formula (2) is reduced, crystallization can be prevented. it can. On the other hand, if the melt viscosity of the phenol resin is increased, that is, if the component with n = 1 in formula (1) is decreased, the crystallinity tends to decrease, so that the crystallinity depends on the melt viscosity. However, the viscosity cannot often be increased depending on the intended use. Therefore, even in the case of a phenol resin having a low melt viscosity, that is, n = 1 in a large amount, the positional relationship of the bond between a methylene group and a hydroxyl group in the structure of the formula (1) However, it is necessary to prevent crystallization by reducing the proportion of para or by reducing the component of formula (2).

The phenol resin of the present invention can be obtained by allowing a basic substance to neutralize by-product hydrogen chloride to be present in the system during the reaction of 4,4′-bischloromethylbiphenyl and phenol. The total number of moles of the benzene ring represented by the formula (1) in which the positional relationship of the bond between the methylene group and the hydroxyl group is ortho (hereinafter referred to as o-coordination number) and the total number of moles of the benzene ring as para (hereinafter referred to as p- The ratio of the coordination number) satisfies the o-coordination number / p-coordination number ≧ 1.5 × V + 1.2 (V is the melt viscosity at 150 ° C., and the unit is Pa · s).

In the reaction for obtaining the phenol resin of the present invention, the amount of 4,4'-bischloromethylbiphenyl used is usually in the range of 1 to 9 mol, preferably 2 to 8 mol, per 10 mol of phenol.

Specific examples of basic substances that can be used include alkali metal hydroxides such as lithium hydroxide, sodium hydroxide, and potassium hydroxide, and alkaline earth metal hydroxides such as magnesium hydroxide, calcium hydroxide, and barium hydroxide. , Alkaline earth metal oxides such as magnesium oxide, calcium oxide, sodium acetate, potassium acetate, sodium oxalate, potassium oxalate, sodium formate, potassium formate, calcium acetate, magnesium acetate, ammonium acetate, sodium carbonate, potassium carbonate, calcium carbonate , Magnesium carbonate, ammonium carbonate, sodium bicarbonate, potassium bicarbonate, ammonium bicarbonate, trisodium citrate, tripotassium citrate, sodium tartrate, potassium tartrate, sodium phosphate, sodium tripolyphosphate, sodium monohydrogen phosphate Um, no sodium dihydrogen phosphate, sodium methoxide, sodium ethoxide, potassium -tert- butoxide, alkali metal methoxide or potassium ethoxide, sodium phenoxide, although potassium phenoxide and the like is not limited thereto. These may be used alone or in combination of two or more. The amount of these basic substances used is usually in the range of 0.02 to 2.0 mol, preferably 0.05 to 2.0 mol, with respect to 1 mol of 4,4'-bishalogenomethylbiphenyl.

This reaction may be solventless or use a solvent. Specific examples of the solvent that can be used include alcohols such as methanol, ethanol and propanol, ketones such as methyl ethyl ketone and methyl isobutyl ketone, toluene, xylene, ethylene glycol, diethylene glycol, acetic acid and the like, but are not limited thereto. There is nothing. These may be used alone or in combination of two or more. These usage-amounts are 5-200 weight part normally with respect to 100 weight part of phenol, Preferably it is the range of 10-100 weight part.

In the reaction, it is usually preferable to add phenol and the above basic substance and gradually add 4,4'-bischloromethylbiphenyl thereto. The temperature in that case is 50 to 150 degreeC normally, Preferably it is the range of 60 to 120 degreeC, and is 0.5 to 10 hours normally, Preferably it is 1 to 4 hours. After completion of the 4,4'-bishalogenomethylbiphenyl addition, the reaction is further carried out at the above temperature for usually 0.5 to 10 hours, preferably 1 to 5 hours. At this time, if the pH of the reaction solution is not acidic, the progress of the reaction is hindered and the polymer may not be polymerized. In this case, acidic substances such as p-toluenesulfonic acid, hydrochloric acid and sulfuric acid are added to the reaction system. After completion of the reaction, excess phenol is distilled off under heating and reduced pressure. Then, the phenol resin of this invention is obtained by melt | dissolving in a water-insoluble solvent normally, repeating water washing, removing a salt, and distilling a solvent off. In addition, when using as a raw material of the epoxy resin of this invention, you may use what distilled the phenol as it is.

The phenolic resin of the present invention thus obtained has an o-coordination number / p-coordination number ≧ 1.5 × V + 1.2 as described above, and does not use a basic substance in the usual method, that is, the above method. The content ratio of the o-coordination number becomes higher than that, and as a result, the precipitation of crystals can be suppressed.

In the phenolic resin of the present invention, in the phenolic resin in which many components of n = 1 are present, in order to achieve the object of the present invention, the content ratio of the formula (2) and the formula (3) in the phenolic resin is Oo / pp (oo is the total number of moles of the compound of formula (3), pp is the total number of moles of the compound of formula (2)) is −0.03 × D + 2.7 (D is the phenol resin) It is preferable that the content ratio (% by weight) of the molecule of n = 1 is greater than or equal to. In addition, the o-coordination number / p-coordination number in the phenol resin of the present invention can be controlled by the addition amount (molar ratio) of the basic substance.

The epoxy resin of the present invention can be obtained by reacting the phenol resin of the present invention with epihalohydrins (epoxidation reaction). Specific examples of epihalohydrins that can be used in the epoxidation reaction include epichlorohydrin, β-methylepichlorohydrin, epibromhydrin, β-methylepibromhydrin, epiiodohydrin, β-ethylepichlorohydrin, and the like. However, industrially available and inexpensive epichlorohydrin or epibromohydrin is preferable.

The reaction is carried out, for example, at 20 to 120 ° C. while adding a solid of an alkali metal hydroxide such as sodium hydroxide or potassium hydroxide as a catalyst to the mixture of the phenol resin and epihalohydrin of the present invention as a catalyst at 0.5 to 20 ° C. Let react for 10 hours. In this case, the alkali metal hydroxide may be used in the form of an aqueous solution. In this case, the alkali metal hydroxide is continuously added and water and epihalohydrin are continuously added from the reaction mixture under reduced pressure or normal pressure. The distillate may be distilled off, the liquid separated to remove water, and the epihalohydrin may be continuously returned to the reaction mixture (in addition, when a solid alkali metal hydroxide is used, it may be dehydrated under reduced pressure). When obtaining an epoxy resin having a low total halogen content, it is preferable to gradually add the alkali metal hydroxide and keep the temperature in the reaction system at 20 to 50 ° C. The moisture in the reaction system is preferably maintained at 0.5 to 10% by weight with respect to epihalohydrin. If it is 0.5% by weight or less, the reaction hardly proceeds, and if it is 10% by weight or more, the total halogen amount tends to increase.

In the above reaction, the amount of epihalohydrin used is usually 1.0 to 20 mol, preferably 2.0 to 15 mol, more preferably 3.0 to 10 mol, per 1 equivalent of the hydroxyl group of the phenol resin of the present invention. is there. The usage-amount of an alkali metal hydroxide is 0.5-1.5 mol normally with respect to 1 equivalent of hydroxyl groups of the phenol resin of Formula (1), Preferably it is 0.7-1.2 mol.

The reaction may be carried out using a solvent having catalytic ability such as an aprotic polar solvent or alcohol. Specific examples of the aprotic polar solvent that can be used include dimethyl sulfone, dimethyl sulfoxide, dimethylformamide, 1,3-dimethyl-2-imidazolidinone, 1,4-dioxane and the like. The amount of the aprotic polar solvent used is usually 5 to 200% by weight, preferably 10 to 150% by weight, based on the weight of the epihalohydrin. Specific examples of alcohols that can be used include methanol, ethanol, and the like. The amount of alcohol used is usually 5 to 100% by weight, preferably 5 to 50% by weight, based on the weight of the epihalohydrin. The use of alcohols facilitates the reaction and the total halogen content is greater than when aprotic polar solvents are used, but less than when these solvents are not used. In particular, when the obtained epoxy resin is used for electronic and electrical component applications such as semiconductors, the total halogen content is preferably 0.000023 mol / g or less. It is preferable to produce using a protic polar solvent.

In the reaction, a quaternary ammonium salt such as tetramethylammonium chloride, tetramethylammonium bromide, trimethylbenzylammonium chloride can also be used as a catalyst. In this case, the amount of the quaternary ammonium salt used is usually 0.001 to 0.2 mol, preferably 0.05 to 0.1 mol, relative to 1 equivalent of the hydroxyl group of the phenol resin of the present invention. These may be used in combination with the above-mentioned solvent.

Usually, these reaction products are dissolved in a solvent such as toluene, methyl isobutyl ketone, methyl ethyl ketone, etc. after removal of excess epihalohydrins and other used solvents under water or reduced pressure without washing with water. An epoxy resin having a low total halogen content can be obtained by adding an aqueous solution of an alkali metal hydroxide such as sodium or potassium hydroxide and reacting again. In this case, the amount of alkali metal hydroxide used is usually 0.01 to 0.2 mol, preferably 0.05 to 0.15 mol, per 1 equivalent of the hydroxyl group of the phenol resin of the present invention. The reaction temperature is usually 50 to 120 ° C., and the reaction time is usually 0.5 to 2 hours. The salt formed as a by-product after completion of the reaction is removed by filtration, washing with water, and the like, and the solvent of toluene, methyl isobutyl ketone, methyl ethyl ketone, etc. is distilled off under heating and reduced pressure to obtain the epoxy resin of the present invention.

Hereinafter, the epoxy resin composition of the present invention will be described. The epoxy resin composition of the present invention contains the epoxy resin of the present invention, a curing agent and a solvent. The epoxy resin of the present invention can be used alone or in combination with other epoxy resins. When used in combination, the proportion of the epoxy resin of the present invention in the total epoxy resin is preferably 20% by weight or more, particularly preferably 30% by weight or more.

Specific examples of other epoxy resins that can be used in combination with the epoxy resin of the present invention include bisphenols (bisphenol A, bisphenol F, bisphenol S, biphenol, bisphenol AD, etc.), phenols (phenol, alkyl-substituted phenol, aromatic-substituted phenol). , Naphthol, alkyl-substituted naphthol, dihydroxybenzene, alkyl-substituted dihydroxybenzene, dihydroxynaphthalene, etc.) and various aldehydes (formaldehyde, acetaldehyde, alkylaldehyde, benzaldehyde, alkyl-substituted benzaldehyde, hydroxybenzaldehyde, naphthaldehyde, glutaraldehyde, phthalaldehyde, crotonaldehyde , Cinnamaldehyde, etc.), polycondensates, phenols and various diene compounds (disic) Polymers with pentadiene, terpenes, vinylcyclohexene, norbornadiene, vinylnorbornene, tetrahydroindene, divinylbenzene, divinylbiphenyl, diisopropenylbiphenyl, butadiene, isoprene, etc., phenols and ketones (acetone, methyl ethyl ketone, methyl isobutyl ketone) , Acetophenone, benzophenone, etc.), phenols and aromatic dimethanol (benzenedimethanol, α, α, α ', α'-benzenedimethanol, biphenyldimethanol, α, α, α', polycondensates with α'-biphenyldimethanol, etc., polycondensates with phenols and aromatic dichloromethyls (α, α'-dichloroxylene, bischloromethylbiphenyl, etc.), polycondensates of bisphenols and various aldehydes. Condensation Glycidyl ether epoxy resins, alicyclic epoxy resins, glycidyl amine epoxy resins, glycidyl ester epoxy resins, etc., which are glycidylated products, alcohols, etc. It is not something. These may be used alone or in combination of two or more.

Examples of the curing agent contained in the epoxy resin composition of the present invention include the phenol resin of the present invention, amine compounds, acid anhydride compounds, amide compounds, phenol compounds, and the like. Specific examples of the curing agent that can be used include diaminodiphenylmethane, diethylenetriamine, triethylenetetramine, diaminodiphenylsulfone, isophoronediamine, dicyandiamide, a polyamide resin synthesized from linolenic acid and ethylenediamine, phthalic anhydride, triethylene anhydride. Mellitic acid, pyromellitic anhydride, maleic anhydride, tetrahydrophthalic anhydride, methyltetrahydrophthalic anhydride, methyl nadic acid anhydride, hexahydrophthalic anhydride, methylhexahydrophthalic anhydride, bisphenols (bisphenol A, bisphenol F, bisphenol S, biphenol, bisphenol AD, etc.), phenols (phenol, alkyl substituted phenol, aromatic substituted phenol, naphthol, alkyl substituted naphthol, Hydroxybenzene, alkyl-substituted dihydroxybenzene, dihydroxynaphthalene, etc.) and various aldehydes (formaldehyde, acetaldehyde, alkylaldehyde, benzaldehyde, alkyl-substituted benzaldehyde, hydroxybenzaldehyde, naphthaldehyde, glutaraldehyde, phthalaldehyde, crotonaldehyde, cinnamaldehyde, etc.) Polycondensates, polymers of phenols and various diene compounds (dicyclopentadiene, terpenes, vinylcyclohexene, norbornadiene, vinylnorbornene, tetrahydroindene, divinylbenzene, divinylbiphenyl, diisopropenylbiphenyl, butadiene, isoprene, etc.) Phenols and ketones (acetone, methyl ethyl ketone, methyl isobutyl , Acetophenone, benzophenone, etc.), phenols and aromatic dimethanols (benzenedimethanol, α, α, α ', α'-benzenedimethanol, biphenyldimethanol, α, α, α' , Α'-biphenyldimethanol, etc.), polycondensates of phenols and aromatic dichloromethyls (α, α'-dichloroxylene, bischloromethylbiphenyl, etc.), bisphenols and various aldehydes Examples thereof include, but are not limited to, polycondensates, modified products thereof, imidazoles, BF ₃ -amine complexes, and guanidine derivatives.

Specific examples of the solvent that can be used in the epoxy resin composition of the present invention include toluene, xylene, methyl ethyl ketone, methyl isobutyl ketone, dioxane, methyl cellosolve, dimethylformamide and the like. These solvents are usually used in an amount of 5 to 300 parts by weight, preferably 10 to 150 parts by weight, based on 100 parts by weight of the resin content.

The epoxy resin composition of the present invention may contain, as necessary, those generally used as an epoxy resin curing accelerator. Examples of the curing accelerator include imidazole compounds such as 2-methylimidazole and 2-ethylimidazole, boron trifluoride complex, triphenylphosphine, trioctylphosphine, tricyclohexylphosphine, triphenylphosphine / triphenylborane, and tetraphenyl. Examples thereof include phosphorus compounds such as phosphonium tetraphenylborate, tertiary amine compounds, etc., and the amount used is 0.01 to 15 parts by weight, preferably 0.1 to 10 parts by weight, based on 100 parts by weight of the epoxy resin. It is.

Furthermore, a known additive can be blended in the epoxy resin composition of the present invention as necessary. Specific examples of additives that can be used include polybutadiene and modified products thereof, modified products of acrylonitrile copolymer, polyphenylene ether, polystyrene, polyethylene, polyimide, fluororesin, maleimide compounds, cyanate ester compounds, silicone gel, and silicone oil. As well as silica, alumina, calcium carbonate, quartz powder, aluminum powder, graphite, talc, clay, iron oxide, titanium oxide, aluminum nitride, asbestos, mica, glass powder, glass fiber, glass nonwoven fabric or carbon fiber, etc. Coloring agents such as materials, surface treatment agents for fillers such as silane coupling agents, mold release agents, carbon black, phthalocyanine blue, and phthalocyanine green.

The epoxy resin composition of the present invention can be obtained by uniformly mixing the above components at a predetermined ratio. After removing the solvent, the epoxy resin composition of the present invention can be made into a cured product by treating at room temperature to 250 ° C. for 30 seconds to 50 hours.
The cured product obtained as described above is excellent in flame retardancy particularly when the phenol resin and the epoxy resin of the present invention are used in combination.
The epoxy resin composition of the present invention can also be used as an adhesive or insulating material for materials constituting printed wiring boards and flexible printed wiring boards.

Hereinafter, the present invention will be described in more detail with reference to synthesis examples and examples. The present invention is not limited to these examples. In the examples, the epoxy equivalent, melt viscosity, and softening point were measured under the following conditions.
1) Epoxy equivalent: Measured by a method according to JIS K-7236.
2) Melt viscosity: Melt viscosity measuring machine in cone plate method at 150 ° C Corn plate (ICI) high temperature viscometer (manufactured by RESEARCH EQUIPMENT (LONDON) LTD.)
Corn No. 3 (measuring range 0-20 poise)
Sample amount: 0.15 ± 0.005 (g)
3) Softening point: measured by a method according to JIS K-7234 4) o-coordination number / p-coordination number (o / p): The position of the methylene group bonded to the hydroxyl group by ¹³ C-NMR measurement. Calculated as a value obtained by dividing the o, p ratio by the coordination number at the o position by the coordination number at the p position (hereinafter referred to as o / p) 5) oo, pp ratio (oo / pp): by high performance liquid chromatography Measurement detection UV (274nm)
6) Content ratio of molecules where n = 1 (ratio of n = 1 body): analytical condition column measured by GPC analyzer; Shodex KF-803 (2) + KF-802.5 (2)
Temperature: 40 ° C
Solvent; Tetrahydrofuran detection; UV (254 nm)
Flow rate: 1 ml / min

Synthesis example 1
A flask equipped with a stirrer, a reflux condenser, and a stirrer was charged with 195 parts by weight of phenol, 50 parts by weight of flaky sodium hydroxide, and 20 parts by weight of methanol, stirred, dissolved, and heated to a temperature of 100 ° C. While being maintained, 151 parts by weight of 4,4′-bischloromethylbiphenyl was continuously added over 4 hours. After the addition was completed, 11 parts by weight of p-toluenesulfonic acid was added, and the reaction was further performed at the same temperature for 3 hours. After completion of the reaction, by-product sodium chloride was removed by washing with water, excess phenol was distilled off from the oil layer under heating and reduced pressure, and 400 parts by weight of methyl isobutyl ketone was added to the residue and dissolved. This resin solution was washed repeatedly with water until the washing solution became neutral, and then methyl isobutyl ketone was distilled off from the oil layer under heating and reduced pressure to obtain 180 parts by weight of the phenol resin (P1) of the present invention. The obtained phenol resin (P1) has a melt viscosity of 0.09 Pa · s, a softening point of 68 ° C., o / p of 2.50, oo / pp of 6.1, and a ratio of n = 1 body of 35.6. % By weight.

Synthesis example 2
The reaction vessel was charged with 230 parts by weight of epichlorohydrin (ECH, the same shall apply hereinafter) and 60 parts by weight of dimethyl sulfoxide (DMSO, the same shall apply hereinafter) to 107 parts by weight of the phenol resin (P1) obtained in Synthesis Example 1, and heated, stirred, After dissolution, 21 parts by weight of flaky sodium hydroxide was continuously added over 2 hours while maintaining the temperature at 45 ° C. After completion of the sodium hydroxide addition, the reaction was further carried out at 45 ° C. for 2 hours and at 70 ° C. for 1 hour. Subsequently, washing with water was repeated to remove the by-product salt and dimethyl sulfoxide, and then excess epichlorohydrin was distilled off from the oil layer under heating and reduced pressure, and 300 parts by weight of methyl isobutyl ketone was added to the residue and dissolved. This methyl isobutyl ketone solution was heated to 70 ° C., 10 parts by weight of a 30% aqueous sodium hydroxide solution was added and reacted for 1 hour, and then the reaction solution was washed with water until the washing solution became neutral. Subsequently, 130 parts by weight of the epoxy resin (E1) of the present invention was obtained by distilling off methyl isobutyl ketone from the oil layer under heating and reduced pressure. The epoxy equivalent of the epoxy resin (E1) was 278 g / eq, the melt viscosity was 0.1 Pa · s, and the softening point was 58 ° C.

Synthesis example 3
In Synthesis Example 1, the same operation was performed except that phenol was changed to 98 parts by weight, sodium hydroxide to 33 parts by weight, and 4,4′-bischloromethylbiphenyl to 110 parts by weight. 135 parts by weight of phenol resin (P2) was obtained. The obtained phenol resin (P2) has a melt viscosity of 0.32 Pa · s, a softening point of 79 ° C., o / p of 2.33, oo / pp of 7.8, and the ratio of n = 1 body is 23.9. % By weight.

Synthesis example 4
In Synthesis Example 2, phenol resin (P1) was added to 87 parts by weight of phenol resin (P2), ECH to 190 parts by weight, DMSO to 50 parts by weight, MIBK to 170 parts by weight, and 30% aqueous sodium hydroxide solution to 5 parts. When the same operation was performed except having changed into the weight part, 105 weight part of epoxy resins (E2) of this invention were obtained. The epoxy equivalent of the epoxy resin (E2) was 288 g / eq, the melt viscosity was 0.33 Pa · s, and the softening point was 70 ° C.

Synthesis example 5
In Synthesis Example 1, phenol was changed to 94 parts by weight, sodium hydroxide to 8 parts by weight of sodium carbonate, and 4,4'-bischloromethylbiphenyl to 100 parts by weight, and p-toluenesulfonic acid and methanol were not used. Except for the above, the same operation was performed to obtain 123 parts by weight of the phenol resin (P3) of the present invention. The obtained phenol resin (P3) had a melt viscosity of 0.32 Pa · s, a softening point of 80 ° C., an oo / pp of 2.1, and a ratio of n = 1 body of 25.3 wt%.

Synthesis Example 6
In Synthesis Example 1, the same operation was performed except that phenol was changed to 127 parts by weight, sodium hydroxide to 5 parts by weight, and 4,4′-bischloromethylbiphenyl to 76 parts by weight. 135 parts by weight of phenol resin (P4) was obtained. The obtained phenol resin (P4) had a melt viscosity of 0.08 Pa · s, a softening point of 67 ° C., an oo / pp of 1.5, and a ratio of n = 1 body of 44.1% by weight.

Comparative Synthesis Example 1
A flask equipped with a stirrer, a reflux condenser, and a stirrer was charged with 195 parts by weight of phenol and 146 parts by weight of 4,4′-bis (methoxymethyl) biphenyl, and 5.3 parts by weight of diethyl sulfate was added, and the temperature was adjusted. The reaction was carried out for 4 hours while maintaining the temperature at 160 ° C. After completion of the reaction, the reaction mixture was cooled, washed with water until the washing water became neutral, and unreacted phenol was distilled off from the oil layer under heating and reduced pressure to obtain 170 parts by weight of a phenol resin (PC1). The obtained phenol resin (PC1) has a melt viscosity of 1.4 Pa · s, a softening point of 73 ° C., o / p of 1.2, oo / pp of 1.4, and a ratio of n = 1 body of 35.8. % By weight.

Comparative Synthesis Example 2
The same operation as in Synthesis Example 2 was performed except that the phenol resin (P1) was changed to 107 parts by weight of the phenol resin (PC1) to obtain 128 parts by weight of the epoxy resin (EC1). Epoxy resin (EC1) had an epoxy equivalent of 278 g / eq, a melt viscosity of 0.07 Pa · s, and a softening point of 57 ° C.

Comparative Synthesis Example 3
In Comparative Synthesis Example 1, the same operation was performed except that phenol was changed to 98 parts by weight, and 132 parts by weight of phenol resin (PC2) was obtained. The obtained phenol resin (PC2) has a melt viscosity of 0.36 Pa · s, a softening point of 80 ° C., o / p of 1.6, oo / pp of 1.9, and a ratio of n = 1 body of 24.6. % By weight.

Comparative Synthesis Example 4
The same operation as in Synthesis Example 4 was performed except that the phenol resin (P2) was changed to 87 parts by weight of the phenol resin (PC2) to obtain 105 parts by weight of the epoxy resin (EC2). The epoxy equivalent of the epoxy resin (EC2) was 288 g / eq, the melt viscosity was 0.33 Pa · s, and the softening point was 70 ° C.

Test Example The epoxy resins obtained in Synthesis Examples 2 and 4 and Comparative Synthesis Examples 2 and 4 were dissolved in methyl ethyl ketone so that the resin concentration would be 70% by weight and stored at 5 ° C. to observe the presence or absence of crystal precipitation. did. The observation results are shown in Table 1.

Examples 1 and 2 and Comparative Examples 1 and 2
In the proportions shown below in Table 2, 25 parts by weight of methyl ethyl ketone and 20 parts by weight of the epoxy resin, curing agent (dicyandiamide), and curing accelerator (2-ethyl-4-methylimidazole) obtained in Synthesis Example and Comparative Synthesis Example Of the present invention and comparative epoxy resin compositions were obtained. These compositions were stored at 5 ° C. for 2 weeks, then impregnated into glass cloth, and dried at 150 ° C. for 5 minutes to obtain a B-stage prepreg. Three prepregs and one copper foil were stacked and heated at 180 ° C. for 2 hours to obtain a cured product. The cured product was measured for moisture absorption and solvent resistance (dimethylformamide) as follows.
・ Hygroscopic rate: 85 ° C./85%/weight increase after 100 hours ・ Solvent resistance: weight increase after immersion in dimethylformamide for 10 days

  From the above results, it is speculated that the comparative epoxy resin is unevenly distributed due to the precipitation of crystals, and there are minute uncured parts in the cured product, where moisture etc. can easily enter. It sometimes increases the possibility of causing defects such as blisters.

Claims (2)

(A) A reaction in which 4,4′-bischloromethylbiphenyl is reacted in the range of 1 to 9 mol with respect to 10 mol of phenol to obtain a phenol resin represented by the following formula (1), Formula (1) obtained by reacting under acidic conditions after adding 4'-bischloromethylbiphenyl in the presence of phenol and a basic substance

(In the formula, n represents the number of repetitions and represents an integer of 1 to 20).
The total number of moles of the benzene ring in which the methylene group is bonded to the o position with respect to the hydroxyl group (o-coordination number) and the methylene group bonded to the p position with respect to the hydroxyl group. The total number of moles of benzene rings (p-coordination number) is o-coordination number / p-coordination number ≧ 1. 5 × V + 1. 2 (V is a melt viscosity at 1550C, and the unit is P a · s), and the content ratio of the n = 1 molecule in the resin is 44.1% by weight or less An epoxy resin composition comprising an epoxy resin (b) curing agent obtained by reacting a phenolic resin with epihalohydrin and a solvent (c). In the phenol resin represented by the formula (1), the following formula (2), formula (3)

Oo / pp (oo is the total number of moles of the compound of formula (3), pp is the formula (2)
The total number of moles of the compound is equal to or greater than −0.03 × D + 2.7 (where D represents the content ratio (% by weight) of n = 1 molecules in the phenol resin). 2. The epoxy resin composition according to 1.