JPS61168617A - Production of high-purity brominated epoxy resin - Google Patents

Abstract

PURPOSE:To obtain the titled resin, by effecting a selective addition reaction between a brominated novolak resin and epichlorohydrin while controlling the formation of by-products, ring-closing the product in the presence of an alkali and finally removing remaining hydrolyzable chlorine, ions, etc. CONSTITUTION:Phenol and an alkylphenol are condensed with an aldehyde, and the condensate is brominated to obtain a brominated novolak resin of the formula (wherein R is H or a 3-20C alkyl, n is 0-15, and X and Y are each 0-2). This resin is reacted with epichlorohydrin in the presence of a catalyst according to the following step to obtain the titled resin. First, said starting materials are subjected to a selective addition reaction to obtain a brominated novolak chlorohydrin ether. This ether is ring-closed in the presence of an alkali to obtain a brominated novolak epoxy resin. This epoxy resin is dissolved in an organic solvent and an alkali is added to this solution to ring-close a small amount of a chlorohydrin ether. In this way, the titled resin is obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a method for producing high-purity brominated epoxy resins used primarily in the electronic and electrical industry fields.

[Prior art and problems to be solved by the invention] Epoxy resins are useful for encapsulating devices such as coils and semiconductors due to their excellent physical properties, electrical properties, mechanical properties, etc. Widely used in electronic and electrical insulation materials such as printed wiring boards. In recent years, the development of electronic equipment has been remarkable, and extremely demanding performance such as high density and high reliability has been required. It is required to be self-extinguishing, flexible, and have excellent properties such as heat resistance and moisture resistance. Furthermore, it is essential that epoxy resins used as electronic and electrical insulating materials have a low hydrolyzable chlorine content.

If the hydrolyzable chlorine content is high, the electrical insulation properties will deteriorate and metals such as semiconductor lead frames will be corroded. It is an essential condition that the amount of high purity epoxy resin is small. The reality is that there is no high-purity brominated epoxy resin that fully satisfies these points.

The present inventors have conducted extensive research into producing a high-purity brominated epoxy resin that is self-extinguishing and has excellent heat resistance, moisture resistance, flexibility, etc., and as a result, has arrived at the present invention. .

[In the formula, R represents hydrogen or an alkyl group having 3 to 12 carbon atoms. (All R's do not have to be the same functional group.) The values indicate an average value of 0 to 15. X and V each represent an integer of 0 to 2. ]

A method for producing a high purity brominated epoxy resin by reacting a brominated novolak type resin represented by the formula with epichlorohydrin in the presence of a catalyst, the method comprising the following steps: It is related to.

First step> A step of selectively adding-reacting a brominated novolac type resin and epichlorohydrin in the presence of a catalyst to obtain a brominated novolac type chlorohydrin ether.

Second Step> A step of subjecting the brominated novolac type chlorohydrin ether to a ring-closing reaction (dehydrochlorination reaction) in the presence of an alkali to obtain a brominated novolac type epoxy resin.

Third step> Dissolve the brominated novolac type epoxy resin in an organic solvent,
A process of adding a small amount of alkali and ring-closing a small amount of remaining O-ruhydrin ether (removing hydrolyzable chlorine) to obtain a high purity brominated epoxy resin.

In the past, various methods of reducing hydrolyzable chlorine have been studied in order to obtain high purity brominated epoxy resins.

The manufacturing method of flame-retardant novolac type epoxy resin was published in
According to the method described in JP 0-10635, brominated novolacs and excess epichlorohydrin are used.

This is a method for obtaining a brominated novolak type epoxy resin in one step in the presence of a catalyst and an alkali, but this production method has the drawbacks of high hydrolyzable chlorine and low purity.

Conventional methods for carrying out epoxidation reactions include: (1) A one-step method in which an addition reaction and a ring-closing (dehydrohalogenation reaction) reaction are carried out at once using an alkali.

■ A two-step method in which an addition reaction is first carried out using a catalyst such as a quaternary ammonium salt, and then a dehydrohalogenation reaction is carried out with an alkali.

etc. are known.

As a method for producing a high-purity flame-retardant epoxy resin, a one-stage method is not a satisfactory method because the yield is low and the hydrolyzable chlorine content is high. Furthermore, the two-stage method alone does not satisfy the purity currently required by the electronics industry.

Therefore, the present inventors conducted intensive studies to obtain a high-purity brominated epoxy resin with a low hydrolyzable chlorine content, and as a result, they arrived at the present invention.

The present invention will be explained in more detail below.

In the first step, the addition reaction of the brominated novolac type resin, the brominated novolac type resin and epichlorohydrin are heated at 10 to 120°C in the presence of a catalyst such as a quaternary ammonium salt. i
! The reaction is carried out with IIJ [.

At this time, by adjusting the type of catalyst and the degree of repulsion of the additive layer 9, it is possible to suppress the production of by-products and undesired intermediates (β-RIO-ruhydrin). Further, it is possible to suppress increase in molecular weight due to polymerization reaction, which is a side reaction.

The amount of epichlorohydrin used is 1 to 20 times the molar equivalent of the phenolic hydroxyl group of the brominated novolak resin as the raw material, preferably 3 to 12 times the molar equivalent. Epichlorohydrin used in excess can be recovered by distillation and reused. Benzene, toluene, methyl ethyl ketone that does not react with epichlorohydrin as a reactive diluent.

Tetrahydrofuran, dioxane, etc. can also be used in combination.

Examples of addition reaction catalysts include quaternary ammonium salts such as tetramethylammonium bromide, benzyltriethylammonium bromide, and tetraethylammonium chloride, phosphonium halides, and alkali metal halides such as potassium bromide and sodium chloride. be able to. They can be used alone or in combination. The amount of catalyst used in the reaction is 0.05 parts by weight per 100 parts by weight of raw materials.
~s, oilt amount.

The reaction temperature varies depending on the type of reactants, but is usually 2.
The temperature is 0 to 140°C, preferably 50 to 90°C. The reaction time is until the addition reaction is substantially completed, and varies depending on the reaction temperature, but is usually 0.5 to 15 hours, preferably 3 to 9 hours.

In the second step, when alkali is continuously added to the brominated novolak-type chlorohydrin ether obtained in the first step, water is azeotropically distilled with epichlorohydrin while maintaining the reaction system under a reduced pressure condition of 50 to 200 m++ HO. The water content in the reaction system is maintained at 0.1 to 5.0%. It is also possible to carry out the process without removing water from the reaction system, but this is disadvantageous from an industrial perspective because the water in the reaction system decomposes epichlorohydrin, and it also reduces the purity yield of the resin. This is not desirable as it may cause

The amount of alkali to be used is 0.85 to 1.0% based on the phenolic hydroxyl equivalent of the brominated novolak resin as a raw material.
00 equivalent. Addition of an excessive amount of alkali is undesirable because by-products increase and the molecular weight increases, resulting in a decrease in yield and a decrease in physical properties.

Examples of the alkali used in the dehydrochlorination reaction include barium hydroxide and sodium carbonate, but sodium hydroxide or water-affected potassium is preferred. The reaction temperature is 30-140°C, preferably 40-90°C.

The reaction time is until the ring-closing reaction (dehydrochlorination) is substantially completed, and varies depending on the reaction temperature, etc., but is usually 0.
．． It is 5 to 10 hours, preferably 2 to 6 hours.

Next, excess epichlorohydrin is distilled off under reduced pressure, and by-produced halide salts are removed by filtration or water washing to obtain a crude brominated novolac type epoxy resin.

In the third step, the brominated novolac type epoxy resin obtained in the second step is dissolved in an organic solvent, 0.01 to 0.20 equivalent of alkali is added per equivalent of phenolic hydroxyl group of the raw material, and the mixture is heated at 50 to 100°C. To obtain high-purity brominated epoxy resin in high yield by ring-closing chlorohydrin ether (hydrolyzable chlorine) at a temperature of I can do it. Examples of the above organic solvents include methyl isobutyl ketone and methyl ethyl ketone.

Toluene and the like can be used alone or in combination.

The characteristics of the present invention are that in the first step, the addition reaction occurs selectively and efficiently while suppressing by-products, and in the second step, the ring-closing reaction ( In the third step, remaining hydrolyzable chlorine and impurity ions are removed to produce a high-purity brominated epoxy resin.

The high purity brominated epoxy resin thus obtained has a hydrolyzable chlorine content of 10% as shown in Table 2.
It has an extremely low content of 0 to 300 pp-, making it extremely useful as a resin for the electronic industry.

(Examples and Effects of the Invention) The present invention will be described in more detail with reference to Examples below, but these Examples are merely illustrative, and the present invention is not limited by the Examples.

It should be noted that all parts hereinafter simply mean parts by weight.

(Examples 1 to 3) 500 parts of the brominated novolac type resin shown in Table 2, 1300 parts of epichlorohydrin, and 5.0 parts of the catalyst shown in Table 1 were placed in a reaction vessel equipped with a thermometer, a cooler, and a stirring device. 1 part and reacted at 10±5°C for 5 to 1 hour. After the addition reaction is completed, a water separator is installed and the amount of 48% shown in Table 1 is added.
% aqueous sodium hydroxide solution was added dropwise over 2 to 4 hours.

At this time, the reaction was carried out under a reduced pressure of 150±50 mHCl, and the produced water was removed by azeotropy with epichlorohydrin, and the reaction was carried out while the epichlorohydrin was returned to the reaction system.

After the completion of the ring-closing reaction, remove excess epichlorohydrin,
1200 parts of methyl isobutyl ketone was added and dissolved, and by-produced sodium chloride was removed by filtration or washing with water. To this solution, 20% aqueous sodium hydroxide solution in the amount shown in Table 1 was added over 1 to 2 hours.
After washing with 00ad four times, methyl isobutyl ketone was finally removed by vacuum distillation to obtain the desired high-purity brominated epoxy resin.

The analytical values of the high purity brominated epoxy resin thus obtained are shown in Table 2.

[Comparative Examples 1 to 2] In a reaction apparatus similar to that used in Examples 1 to 3, 500 parts of brominated novolac type resin and 1300 parts of epichlorohydrin were added.
48% sodium hydroxide solution in the amount shown in Table 1 was added dropwise at 70±5° C. over 2 to 4 hours. At this time, the reaction system was kept under reduced pressure of 150 ± 50 awHO,
The produced water was removed by azeotropy with epichlorohydrin, and the epichlorohydrin was returned to the reaction system while the reaction was carried out.

After the reaction, excess epichlorohydrin was removed by vacuum distillation, and the product was dissolved in methyl isobutyl ketone (1200 g).
The by-produced sodium chloride was removed by filtration and washing with water, and finally, methyl isobutyl ketone was removed by vacuum distillation to obtain a brominated epoxy resin.

The results are shown in Table 2.

Summer LU doctor

Claims (1)

[Claims] (1) The following general formula [I] obtained by brominating a co-condensate of phenol and/or alkylphenols and aldehydes [I] ▲There are mathematical formulas, chemical formulas, tables, etc.▼ [I] (In the formula, R is hydrogen or Represents an alkyl group having 3 to 12 carbon atoms. (Rs may not all be the same functional group.) n represents an average value of 0 to 15. x and y each represent an integer of 0 to 2.] A method for producing a high purity brominated epoxy resin by reacting the represented brominated novolac type resin with epichlorohydrin in the presence of a catalyst, the method comprising the following steps: <First step> A step of selectively adding a brominated novolac type resin and epichlorohydrin in the presence of a catalyst to obtain a brominated novolac type chlorohydrin ether. <Second step> Brominated novolac type chlorohydrin A step of ring-closing the ether in the presence of an alkali to obtain a brominated novolak epoxy resin. <Third step> Dissolving the brominated novolak epoxy resin in an organic solvent,
A process of adding a small amount of alkali and ring-closing a small amount of chlorohydrin ether to obtain a high-purity brominated epoxy resin.