JPS63238122A - Epoxy resin and production thereof - Google Patents

Abstract

PURPOSE:To obtain the titled resin, which is a liquid at ordinary temperature, having excellent operability and capable of providing cured products having excellent physical properties, by reacting an alpha,alpha'-dialkoxy-p-xylene with phenol under specific conditions and reacting the resultant compound with an epihalohydrin. CONSTITUTION:An alpha,alpha'-dialkoxy-p-xylene expressed by formula I (R is <=4C lower alkyl) is initially reacted with (B) phenol at >=4 molar ratio in the presence of an acid catalyst (e.g. p-toluenesulfonic acid), preferably at 130-240 deg.C. At this time, an alcohol or unreacted phenol formed with progress of the reaction are removed. (C) The resultant phenolaralkyl resin expressed by formula II (n is 0-5) is then reacted wit (D) an epihalohydrin in the presence of a hydrogen halide acceptor (e.g. potassium hydroxide), normally at 40-120 deg.C and preferably pH 6.5-10 to afford the aimed resin.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a novel low molecular weight epoxy resin and a method for producing the same.

This epoxy resin has excellent heat resistance, mechanical properties, and workability, and can be used for many purposes such as casting, lamination, coating, and semiconductor sealing.

(Prior Art) Conventionally, epoxy resins have been used in a wide variety of applications, such as matrix resins for heat-resistant composite materials and heat-resistant adhesives. Typically, there are those having a phenol skeleton such as bisphenol A and bisphenol sulfone, and those having an aromatic amine skeleton such as 4,4-diaminodiphenylmethane and 3,3'-diaminodiphenylsulfone. These can be obtained by reacting bisphenols and aromatic diamines with shrimp halohydrin. This epoxy resin is generally mixed with a suitable curing agent and used for the various applications mentioned above by reacting the epoxy groups with the functional groups of the curing agent.

Further, as special products, epoxidized products of phenol novolac resin and epoxidized products of phenol-xylene bonded resin (Japanese Patent Publication No. 13782/1982) are known, and are used in the same manner.

[Problem that the invention seeks to solve]

The performance of the conformal epoxy resin as a cured product is as follows:
Although it has excellent performance in terms of electrical properties, dimensional stability, and chemical resistance, it is still insufficient in terms of heat resistance.

Generally, in order to improve heat resistance, a method is taken to increase the crosslinking density, but on the other hand, this inevitably results in the resin becoming hard and brittle. In addition, as another method for improving heat resistance, introducing sulfone bonds, amine bonds, etc. into the epoxy resin skeleton increases the hygroscopicity of the cured resin, which is not preferable in terms of water resistance.

In recent years, it has become necessary to add more advanced performance to these epoxy resins.

For example, materials for composite materials, adhesives, etc. are required to withstand instantaneous impacts such as stress concentration as external stress.

For this reason, ideally, elastic deformation like rubber is attracting attention as an important element. As a criterion for determining such elastic deformation, elongation of the matrix resin at break is especially important. The greater the elongation of the matrix resin, the more it can compensate for the drawbacks of reinforcing agents such as glass fiber and carbon fiber required for composite materials. In other words, the strength of the composite material as a whole is improved.

In addition, such composite materials and adhesives are generally wet-impregnated and molded, and if the epoxy resin is liquid at room temperature, it is necessary to use unnecessary organic solvents and work in a heated molten state. As a result, the amount used is reduced and workability is improved.

Furthermore, long-term storage stability is also important for these matrix resins, and they are also required to be less susceptible to deterioration due to oxygen in the air. This oxidation resistance is mainly derived from the structure of the resin, and this problem cannot be solved with a phenol novolac resin structure.

Recently, among these required elements, an epoxidized product of phenol-xylene bonded resin with improved heat resistance and oxidation resistance has been proposed (Japanese Patent Publication No. 47-1378
2, Japanese Unexamined Patent Publication No. 112813/1983).

However, all of these epoxy resins are composed of a composition in which phenol and aralkyl ether are subjected to a condensation reaction so that substantially no unreacted materials remain.

For this reason, the amount of phenol used per mole of bifunctional aralkyl ether is limited to a range of 1.3 to 3 moles, but resins obtained within this range have a large molecular weight and have poor fluidity and performance. I am not satisfied with the results. Therefore, not only is it inefficient in terms of workability, but its inherent mechanical properties, especially its elongation at break, do not reach the level required for composite materials.

The present invention was made in view of the above problems, and its purpose is to exhibit sufficient performance in heat resistance, water resistance, and oxidation resistance, excellent mechanical properties such as impact resistance, and further improve workability. It is an object of the present invention to provide an epoxy resin that is excellent and useful for use as a matrix resin for heat-resistant composite materials, a heat-resistant adhesive, etc., and a method for producing the same.

(Means for Solving the Problems) The present inventors have completed the present invention as a result of intensive studies to achieve the above object.

That is, the present invention provides an epoxy resin obtained by reacting a phenol aralkyl resin represented by the general formula (a) (wherein n is an integer of 0 to 5) and epihalohydrin in the presence of a hydrogen halide acceptor. resin, and α, α゛-dialkoxy p-xylene represented by the general formula (b) ROGII (b) (wherein R represents a lower alkyl group having 4 or less carbon atoms) Unreacted phenol is recovered from the reaction product obtained by reacting phenol in a molar ratio or higher, and the reaction product containing a phenol aralkyl resin represented by general formula (a) as a main component and epihalohydrin are combined with a hydrogen halide acceptor. This is a method for producing an epoxy resin characterized by carrying out the reaction in the presence of.

The epoxidized phenol aralkyl resin obtained by the method of the present invention provides a good cured product when combined with various curing agents. For example, when an acid anhydride (trade name Epicure Y II-306, manufactured by Shell Chemical Co., Ltd.) is combined as a curing agent, the tensile strength and elongation rate are more than double that of epoxy resin with a bisphenol A skeleton. . Also, those having a skeleton of a phenol-xylene bonded resin obtained with a molar ratio within the range exemplified in Japanese Patent Publication No. 47-13782 (the molar ratio of phenol to α,α°-dialkoxy-p-xylene is 1.9:1) ; Softening point 73.5
℃), both tensile strength and elongation rate are found to be about 1.5 times better.

Furthermore, since the epoxy resin of the present invention is oily at room temperature,
Operations such as blending, coating, and impregnation are extremely easy, and a homogeneous cured product can be obtained.

In order to obtain the above effects, a phenol aralkyl resin represented by the general formula (a) having a repeating unit n of 5 or less is used in the present invention. However, in order to obtain a more remarkable effect, it is desirable that the amount of n=5 is less than 15% by weight, or the total of n=o and n=1 is preferably 50% by mole or more, Furthermore, n=
It is more desirable that the total of o and n=1 is 60 mol% or more.

General formula (a
A specific example of a method for obtaining a phenol aralkyl resin represented by () will be described below.

First, 4 or more moles of phenol, preferably 5 to 20 moles, more preferably 6 to 20 moles, is added to 1 mole of α,α°-dialkoxy p-xylene represented by the general formula (b).
It is added in an amount of 15 mol, and the temperature is raised as it is in the presence of an acid catalyst to cause the reaction to occur at the temperature described below.

The alcohol produced as the reaction progresses is trapped outside the system. If necessary, trace amounts of alcohol remaining in the system are removed from the thread using nitrogen. After the reaction is completed, unreacted phenol naturally remains, but this is distilled off under vacuum or by steam distillation, and the residual resin obtained is the phenol aralkyl resin as described above. It is.

When the number of carbon atoms in the alkyl group R in this α, α°-dialkoxy p-xylene is 4 or less, the reaction is rapid;
In addition, the number of carbon atoms is 4, that is, in the butyl group, ter
T-butyl groups tend to react slowly. Therefore, those used in the present invention are preferably α, α°-dimethoxy p-xylene, α, α°-dimethoxy p-xylene, α, α°-dimethoxy p-xylene,
xylene, α, α゛-di-n-propoxy p-xylene, α, α°-isopropoxy p-xylene, α, α
Examples include, but are not limited to, -di-n-butoxy-p-xylene, α,α°-di-5ec-butoxy-p-xylene, α,α°-diisobutyl-p-xylene, and the like.

The reaction temperature needs to be 110°C or higher; if it is lower than 110°C, the reaction will be extremely slow. In addition, in order to shorten the reaction time as much as possible, approximately 130 to 240
A temperature range of °C is preferred. Reaction time is 1 to 20 hours.

Acid catalysts include inorganic or organic acids, in particular mineral acids, such as hydrochloric acid, phosphoric acid, sulfuric acid or formic acid, or zinc chloride,
A free sol fluorine catalyst such as stannic chloride or ferric chloride may be used alone or in combination with an organic sulfonic acid such as methanesulfonic acid or p-toluenesulfonic acid.

The amount of catalyst used is about 0.01 to 5% by weight of the total weight of phenol, α, α°-dialkoxy p-xylene.

A known method can be applied to epoxidize the reaction product containing the phenol aralkyl resin as a main component.

That is, the reaction is carried out using residual resin and epihalohydrin, preferably epichlorohydrin, usually within a temperature range of 40 to 120 DEG C., in the presence of a hydrogen halide acceptor.

Particularly suitable as hydrogen halide acceptors according to the invention are alkali metal hydroxides such as potassium hydroxide, sodium hydroxide. A hydrogen halide acceptor is gradually added to the heated mixture of the phenolic aralkyl resin and epihalohydrin and the hydrogen halide acceptor is added slowly to the heated mixture of the phenolic aralkyl resin and epihalohydrin.
It is preferred to maintain H between about 6.5 and 10.

The proportion of epihalohydrin used in the reaction depends on the hydroxyl group content of the residual resin, but usually an excess of 2.0 to 30 equivalents, preferably 10 equivalents or less in consideration of economic efficiency, is used. Excess acceptor substances and by-product salts are removed from the reaction product by means such as vacuum distillation or washing with water.

The epoxy resin produced by the method of the invention can also be cured with conventional curing agents.

Typical examples of hardeners are conventional hardeners for epoxy resins such as bis(4-aminophenyl)methane, aniline/formaldehyde resins, bis(4-aminophenyl)sulfone, propane-1,3-diamine, hexa Methylenediamine, diethylenetriamine, triethylenetetramine, 2,2,4-trimethylhexamino-1,6-diamine, m-xylylenediamine, bis(4-aminocyclohexyl)methane, 2,2-bis(4-aminocyclohexyl) ) propane and 3-aminomethyl-3,5,
Aliphatic, cycloaliphatic, aromatic and heterocyclic amines such as 5-trimethylcyclohexylamine (isophorone diamine); polyaminoamides such as those obtained from aliphatic polyamines and trimerization or trimerized fatty acids; resorcinol,
Polyphenols such as hydroquinone, 2,2-bis(4-hydroxyphenyl)propane and phenol/aldehyde resins; polythiols such as those commercially available as Thiochols; e.g. phthalic anhydride, tetrahydrophthalic anhydride, hexahydrophthalic anhydride Hexachloroendomethylenetetrahydrophthalic anhydride,
Includes pyromellitic anhydride, 3,3°,4,4-benzophenonetetracarboxylic dianhydride, the acids of said anhydrides and polycarboxylic acids and their anhydrides such as isophthalic acid and terephthalic acid. If the curing agent is a polycarboxylic acid or anhydride thereof, usually 0.4 to 1.1
An equivalent amount of carboxyl or anhydride group is used per equivalent of epoxy group. If the curing agent is a polyphenol, 0.75 to 1.0% per equivalent of epoxy group.
It is convenient to use 25 phenolic hydroxyl groups.

Catalytic hardeners are generally used in amounts of 1 to 40 parts by weight per 100 parts of epoxy.

〔Example〕

Hereinafter, the present invention will be explained in more detail with reference to Examples.

Example 1 α, α°-Dimethoxy p-
250 g (1.5 moles) of xylene, 847 g of phenol
(9.0 mol), and para-toluenesulfonic acid 1.1
g was charged, and stirring was continued while maintaining the mixed solution at 130°C to 150°C. During the reaction, generated methanol was sequentially removed from the thread through the trap.

After 3 hours, no methanol was generated and the condensation was completed.

Next, unreacted phenol is distilled under two pressures, and the general formula (a) is expressed as
393 g of a phenol aralkyl resin composition having the structure was obtained.

The composition of the obtained resin was measured by high performance liquid chromatography and found that n=o was 60J, n=1 was 24.3, and n
=2 is 9.2, n=3 is 3.8, n≧4 is 2.4
(mol%).

393g of this resin and 1100g of epichlorohydrin (1
1.9 mol) was mixed and charged into a reaction vessel equipped with a stirrer, a Dean-Stark azeotropic distillation trap, and a dropping funnel.

While stirring this mixture, the temperature was raised to 115-119°C, and then at the same temperature, 275 g of a 40% aqueous sodium hydroxide solution was added.
was added dropwise over 4 hours, and the distilled water was continuously separated and collected.
The epichlorohydrin phase was returned to the reactor. After the dropwise addition is completed, the reaction is completed by removing the distilled water.

After that, excess epichlorohydrin was distilled under reduced pressure, and 1500 g of the reaction product was converted into methyl isobutyl ketone (MIB).
After filtering out sodium chloride and a slight excess of sodium hydroxide, the solvent was distilled off under reduced pressure to obtain 465 g of a yellow oily epoxy resin.

Epoxy equivalent is 227g/eq, viscosity (Tokyo Keiki E)
(by type viscometer) is 468 g/cm-sec (35 g/cm-sec)
℃).

The results of this IR analysis (liquid film method) are shown in FIG.

Example 2 α,α゛-dimethoxyp-
250 g (1.5 moles) of xylene, 1411 phenol
g (15 mol), and para-toluenesulfonic acid 8.3
g was charged, and the mixed solution was stirred while being maintained at 130 to 150°C.

The methanol produced was removed by distillation.

After 2 hours, no methanol was generated and the condensation was completed. Unreacted phenol was removed by distillation under reduced pressure to obtain 385 g of a phenol aralkyl resin composition having the structure of general formula (a).

The composition of the obtained resin was measured by high performance liquid chromatography and found that n=o was 76.5. n=1 is 18.6,
n=2 was 4.4, and n≧3 was 0.5 (mol%).

385g of this resin and epichlorohydrin
(11.9 mol) were mixed and charged to a reaction vessel equipped with a stirrer, a Dean-Stark azeotropic distillation trap, and a dropping funnel.

The temperature of this mixture was raised to 115-119°C while stirring, and at the same temperature, 275 g of a 40% aqueous sodium hydroxide solution was added dropwise over 4 hours. The distilled water was continuously separated and collected, and the epichlorohydrin phase was transferred to the reactor. I returned it to . After the dropwise addition is completed, the reaction is completed by removing the distilled water.

After that, excess epichlorohydrin was distilled under reduced pressure, and 1500 g of methyl isobutyl ketone (MIBK) was obtained as a reaction product.
After filtering out sodium chloride and a slight excess of sodium hydroxide, the solvent was distilled off under reduced pressure to obtain 451 g of a yellow oily epoxy resin.

The epoxy equivalent is 219 g/eq, and the viscosity (according to Tokyo Keiki E-type viscometer) is 123 g/cm-sec (15
℃).

Comparative Example 1 α, α°-Dimethoxy p-
Xylene 166g (1.0 mol), phenol 179g
(1.9 mol) and 1.5 g of para-toluenesulfonic acid were charged, and the mixed solution was stirred while being maintained at 130°C to 150°C.

Methanol produced during the reaction was distilled off.

After 3 hours, no methanol was generated, and when the condensation was completed, 280 g of a phenol aralkyl resin composition having the structure of general formula (a) was obtained.

The average molecular weight of the obtained resin was 2054, and estimated from this average molecular weight, the average repeating unit π was IO.

Further, the softening point (according to a JIS-2548 ring and ball softening point measuring device) was 73.5°C.

240g of this resin and 694g of epichlorohydrin (7,
5 mol) were mixed and charged into a reaction vessel equipped with a stirrer, a Dean-Stark azeotropic distillation trap, and a dropping funnel.

The temperature of this mixture was raised to 115-119°C with stirring, and then 165 g of a 40% aqueous sodium hydroxide solution was added dropwise over 3 hours at the same temperature, the distilled water was continuously separated and collected, and the epichlorohydrin phase was transferred to the reactor. I returned it to . After the dripping is finished,
The reaction is terminated by removing the distillate water.

After this, excess epichlorohydrin was distilled under reduced pressure, and the reaction product was converted to methyl isobutyl ketone (MIB)
After filtering out sodium chloride and a slight excess of sodium hydroxide, the solvent was distilled off under reduced pressure to obtain 275 g of a yellow solid epoxy resin.

The epoxy equivalent is 274 g/eq, and the softening point (according to JIS-2548 ring and ball softening point measurement device) is 5.
Cool at 4°C.

Usage Example 1 Each of the epoxy resins obtained in Example 1.2 and Comparative Example 1, and Ebicure 828 (manufactured by Shell Chemical Co., Ltd.) introduced from bisphenol A was added with liquid MDA (Ebicure 2; Shell Chemical Co., Ltd.) as a curing agent. ) were mixed under the conditions shown in Table 1, and each mixture was cast into a mold.
The mechanical properties of the cured resin after processing were measured. The results are shown in Table-1.

Use Example 2 An acid anhydride (Ebicure YH-306: (manufactured by Ciel Chemical) and 2,4.6-tris(dimethylaminomethyl)phenol (TAP) as an accelerator were blended under the conditions shown in Table 2, the mixtures were cast, and the cured resin after processing. Mechanical properties were measured. The results are shown in Table-2.

(Notes on Tables 1 and 2) ・Distribution・・・・・・・・・Weight ratio.

・Gelation time: Based on JIS-6910.

・Heat deformation temperature: According to JIS, 7207.

・Water absorption rate when boiling: Boiling at 100℃/2 hours.

・Bending strength: According to JIS-7203.

・Tensile strength...---JIS, ni-71
According to 13.

〔Effect of the invention〕

As explained above, the epoxy resin of the present invention is liquid at room temperature, so it has excellent workability, and its cured product shows sufficient performance in heat resistance, water resistance, oxidation resistance, and furthermore, Since it has excellent mechanical properties such as 8T impact resistance, it can be expected to be used in a variety of applications, especially in the field of electronic materials, where the above-mentioned performance has long been desired.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing the IR analysis results (liquid film method) of the epoxy resin of Example 1.

Claims (1)

[Claims] 1) General formula (a) ▲There are mathematical formulas, chemical formulas, tables, etc.▼(a) (However, n in the formula represents an integer from 0 to 5.) Phenol aralkyl resin and An epoxy resin obtained by reacting epihalohydrin in the presence of a hydrogen halide acceptor. 2) General formula (b) ▲There are mathematical formulas, chemical formulas, tables, etc.▼(b) (However, R in the formula represents a lower alkyl group having 4 or less carbon atoms.) Unreacted phenol is recovered from the reaction product obtained by reacting alkoxy-p-xylene with phenol in a molar ratio of 4 or more. (where n in the formula is an integer of 0 to 5.) An epoxy resin characterized by reacting a reaction product containing a phenol aralkyl resin represented by the formula as a main component with epihalohydrin in the presence of a hydrogen halide acceptor. manufacturing method.