JPH05148344A - Flame-retarding epoxy resin composition - Google Patents

Abstract

PURPOSE:To obtain a resin composition for laminates having excellent heat resistance, low viscosity and excellent moldability by adding a curing agent to an adduct among a diepoxy resin, a polyepoxy resin, a tetrabromobisphenol and a specified ether. CONSTITUTION:The objective composition essentially consists of an epoxy curing agent and an adduct prepared by reacting at least one diepoxy resin, a polyepoxy resin and a diglycidyl ether of tetrabromobisphenol A. This reaction is performed, for example, by reacting the respective components in the presence of a basic catalyst such as triphenylphosphine or imidazole and in the presence or absence of a solvent. These components may be reacted with each other in one step or in successive steps, for example, in such a manner that tetrabromobisphenol A is first reacted with a diglycidyl ether of tetrabromobisphenol A, and the product is reacted with the other epoxy resin.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a flame-retardant epoxy resin composition which is particularly useful as a laminate material.

[0002]

2. Description of the Related Art Conventionally, as a material for an industrial printed wiring board, a combination of a bisphenol type epoxy resin, a heat resistance imparting component such as a novolac type epoxy resin as required, and a dicyandiamide as a curing agent has been used. .. In recent years, along with surface mounting, high density mounting, and multilayered printed wiring boards, improvement in heat resistance of the boards has been required. Conventionally, in order to meet such demands, a method of preliminarily reacting a heat resistance imparting component such as a bisphenol type epoxy resin and a novolac type epoxy resin with tetrabromobisphenol A (this preliminary reaction may be referred to as prereact) is performed. I've been told.

[0003]

When pre-reacting by adding a heat resistance-imparting component such as a novolac type epoxy resin for the purpose of improving the heat resistance, the heat resistance is improved but the viscosity of the resin is increased, and the heat resistance is particularly high. When the amount of the property-imparting component is increased, impregnability into glass fiber or the like is deteriorated, which causes adverse effects such as deterioration of moldability and productivity. An object of the present invention is to obtain a flame-retardant epoxy resin composition for laminated boards, which has low viscosity and excellent moldability while maintaining the feature of heat resistance.

[0004]

The present invention provides (A) at least one difunctional epoxy resin, (B) polyfunctional epoxy resin, (C) tetrabromobisphenol A and (D).
The present invention relates to a flame-retardant epoxy resin composition containing an adduct obtained by previously reacting a diglycidyl ether of tetrabromobisphenol A and an epoxy curing agent as essential components.

The bifunctional epoxy resin used in the present invention is a resin having two epoxy groups in one molecule. For example, diglycidyl ethers of dihydric phenols such as catechol, resorcin, and handloquinone, or
General formula 2

[0006]

[Chemical 2] (In the formula, Z is

[Chemical 3] -S -, - SS -, - SO 2 - or -CO- represent,
R _{6 to} R ₁₁ each independently represent a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, or an aryl group. ) Is a diglycidyl ether of bisphenol. Specific examples of the substituents R _{6 to} R ₁₁ include hydrogen atom, methyl group, ethyl group, propyl group, butyl group, amyl group, hexyl group, phenyl group, naphthyl group, etc. (Including the body).

To convert the above dihydric phenols and the bisphenols represented by Chemical Formula 2 into glycidyl ethers,
A conventionally known method in which a phenol and an epihalohydrin are reacted in the presence of an alkali such as caustic soda can be used. Particularly when a high-purity product is to be obtained, JP-A-60-31
As described in Japanese Patent No. 517, the reaction under an aprotic solvent is preferable.

Examples of the polyfunctional epoxy resin used in the present invention include phenol novolac glycidyl ether, cresol novolac glycidyl ether, bisphenol A novolac glycidyl ether and other novolac type epoxy resins, phenols and acrolein, croton. Glycidyl ether compound of the polycondensation product with aldehyde, glyoxal, hydroxybenzaldehyde, hydroxyacetophenone, isopropenylacetophenone, etc.

[0009]

[Chemical 4] (In the formula, R _{1 to} R ₅ are each independently a hydrogen atom, an alkyl group or an alkoxy group having 1 to 6 carbon atoms, X is independently a hydrogen atom, a chlorine atom or a bromine atom, and n is an average. It is the number of repeating units and is a number of 1 to 6.). In the above Chemical Formula 4, when R _{1 to} R ₅ are specifically exemplified, a hydrogen atom,
Examples thereof include a methyl group, an ethyl group, a propyl group, a butyl group, an amyl group, a hexyl group, a methoxy group, an ethoxy group, a propoxy group, a butoxy group and the like (those having isomers include each isomer). Further, in the above Chemical formula 4, the repeating structural formula

[0010]

[Chemical 5] (In the formula, R _{1 to} R ₅ , X and n are the same as those in Chemical Formula 4 above.) Means that

[0011]

[Chemical 6] (In the formula, R _{1 to} R ₅ and X have the same meanings as those in the above chemical formula 4.) and the following chemical formula 7

[0012]

[Chemical 7] (In the formula, R _{1 to} R ₅ and X represent the same as those in the above-mentioned chemical formula 4.) and a structure unit in which a structural unit represented by the formula 4 is mixed or present independently, and these structures in one molecule. This shows the structure of a so-called polydisperse type oligomer having a distribution in the number of units. The number of repeating units n represents the number of these average values. If n exceeds 6, the melt viscosity of the composition becomes too high, and the coating properties and moldability are adversely affected, for example, the impregnability into glass cloth deteriorates.

Of the above-mentioned polyfunctional epoxy resins, the one preferred in the present invention is the polyfunctional epoxy resin represented by the above chemical formula 4.

The polyfunctional epoxy resin represented by the above chemical formula 4 is obtained by condensing, for example, phenols and aldehydes or ketones containing a phenolic hydroxyl group under an acidic catalyst,
It can be obtained by glycidyl etherification with epichlorohydrin or the like.

Examples of phenols include phenol,
Cresol, ethylphenol, propylphenol,
Examples thereof include butylphenol, amylphenol, hexylphenol, xylenol, methylbutylphenol and the like (those having isomers include each isomer). These phenols can be used alone or in combination.

Examples of aldehydes or ketones having a phenolic hydroxyl group include hydroxybenzaldehyde, methylhydroxybenzaldehyde, dimethylhydroxybenzaldehyde, hydroxyacetophenone, methylhydroxyacetophenone, dimethylhydroxyacetophenone, hydroxyphenylethylketone, hydroxyphenylbutylketone, Hydroxyphenylhexyl ketone and the like.

The reaction of phenols with aldehydes or ketones containing a phenolic hydroxyl group is carried out by inorganic acids such as hydrogen chloride and sulfuric acid, acetic acid, p-toluenesulfonic acid,
It can be obtained by a method of performing a post-treatment such as condensation with an organic acid such as thioglycolic acid or the like, an acidic catalyst such as a Lewis acid, washing with water, and distillation of unreacted phenols. The polyfunctional epoxy resin also includes a chlorinated or brominated resin for the purpose of imparting flame retardancy.

Further, in order to glycidyl etherify the condensate of the above-mentioned phenols and aldehydes or ketones containing a phenolic hydroxyl group, the phenols and epihalohydrin are reacted in the presence of an alkali such as caustic soda. Known methods can be used. In particular, when a highly pure product is obtained, the reaction in an aprotic solvent is suitable as described in JP-A-60-31517.

The diglycidyl ether of tetrabromobisphenol A used in the present invention is tetrabromobisphenol A glycidyl etherified with epichlorohydrin and has an epoxy equivalent of 340 to 340.
600.

In the present invention, the amount of tetrabromobisphenol A and diglycidyl ether of tetrabromobisphenol A used is such that the bromine content of the resin component is 15% by weight to 2%.
An amount of 5% by weight is desirable. If the bromine content is too low, the flame retardancy is insufficient, and if it is too high, the physical properties such as heat resistance deteriorate, which is not preferable.

The reaction of a polyfunctional epoxy resin, a difunctional epoxy resin, tetrabromobisphenol A and a diglycidyl ether of tetrabromobisphenol A is carried out by a known method. For example, the above components are reacted in the presence of a basic catalyst such as triphenylphosphine or imidazole in the absence or presence of a solvent. Each component may be reacted at once, or tetrabromobisphenol A and a diglycidyl ether of tetrabromobisphenol A are first reacted, and then another epoxy resin is reacted in a stepwise manner. You may react.

As the epoxy curing agent used in the present invention, known epoxy curing agents can be used. Examples thereof include polyphenols such as phenol novolac, cresol novolac, and 1,1,1-trishydroxyphenylethane, and aromatic compounds. Examples include amine-based curing agents such as amines and aliphatic amines, acid anhydrides, dicyandiamide, and hydrazide compounds. Preferred are dicyandiamide and polyhydric phenols. Further, the blending amount thereof is preferably 0.3 to 1.2 equivalents with respect to the epoxy group.

In the present invention, known additives such as a curing accelerator, a flame retardant, a release agent, a surface treatment agent and a filler may be added to the composition depending on the purpose of use. Imidazoles and tertiary amines as curing accelerators, antimony trioxide, red phosphorus, etc. as flame retardants, waxes, zinc stearate, etc. as mold release agents, and silane coupling as surface treatment agents. An agent can be mentioned. Examples of the filler include silica, alumina, talc, clay, glass fiber and the like.

When the epoxy resin composition of the present invention is used for a laminated board, the epoxy resin composition is uniformly dissolved in a solvent such as methyl ethyl ketone, ethylene glycol monomethyl ether, dimethylformamide or the like to prepare glass fiber, polyester fiber or polyamide. A prepreg obtained by impregnating a base material made of woven cloth, mat, paper or a combination thereof made of organic or inorganic fiber such as fiber or alumina fiber and heating and drying can be hot press molded.

[0025]

The epoxy resin composition of the present invention provides a cured molded article having excellent heat resistance, low viscosity and excellent impregnability.

[0026]

EXAMPLE The resin viscosity was measured by dissolving 75 parts by weight of the resin in 25 parts by weight of methyl ethyl ketone and using a B-type viscometer (25 ° C.). The glass transition temperature of the cured molded product was measured using a dynamic viscoelasticity measuring device (Rheograph Solid, manufactured by Toyo Seiki Co., Ltd.).

Reference Example 1 p-hydroxybenzaldehyde 183.2 g, 2-butyl-5-methylphenol 341.8 g, m-cresol 75.0 g, p-toluenesulfonic acid 0.50 g,
420 g of toluene was charged into a reaction vessel equipped with a thermometer and a condenser with a separation tube, and the temperature of the solution was raised to 10 ° C at 115 ° C.
Stir for hours. During this period, azeotropic toluene and water were cooled and liquefied, and the organic layer was allowed to react while being returned to the reaction system. After completion of the reaction, the solution was neutralized with a 10% aqueous sodium hydroxide solution and then concentrated under reduced pressure to obtain a reddish brown resin.

92.4 g of the resin thus obtained
(Phenolic hydroxyl group 0.7 mol) was charged into a reaction vessel equipped with a thermometer, a stirrer, a dropping funnel, and a condenser with a separation tube, and dissolved in 453.3 g of epichlorohydrin and 226.7 g of dimethyl. While maintaining the inside of the reaction system at 41 torr, at a temperature of 48 ° C., 57.6 g of a 48.6% aqueous sodium hydroxide solution was continuously added dropwise over 5 hours.

During this period, while keeping the temperature at 48 ° C., the azeotropically distilled epichlorohydrin and water were cooled and liquefied, and the reaction was carried out while returning the organic layer to the reaction system. After completion of the reaction, unreacted epichlorohydrin was removed by concentration under reduced pressure, diglycidyl ether containing a by-product salt and dimethyl sulfoxide was dissolved in methyl isobutyl ketone, and the by-product salt and dimethyl sulfoxide were removed by washing with water. The epoxy equivalent of the diglycidyl ether compound thus obtained is 2
It was 05 g / equivalent.

Reference Examples 2 to 8 In a reaction vessel equipped with a thermometer, a stirrer, and a condenser, the resin of Reference Example 1 was used as a polyfunctional epoxy resin, and the glycidyl ether compound of bisphenol A was used as a bifunctional epoxy resin (Sumitomo Chemical Industries ( Product name: Sumiepoxy E
LA-128, epoxy equivalent 188 g / equivalent), and further tetrabromobisphenol A and a diglycidyl ether compound of tetrabromobisphenol A (Sumitomo Chemical Co., Ltd., trade name: Sumiepoxy ESB-400, epoxy equivalent 400 g / equivalent) Were charged in the amounts shown in Table 1 and Table 2 (bromine content was adjusted to 19% by weight),
Further, 9 g of methyl ethyl ketone was charged and heated to 110 ° C. to completely dissolve it, and then triphenylphosphine 0.
02g was added and it was made to react at 110 degreeC for 5 hours. Then, the solvent was removed by concentration under reduced pressure to obtain a resin. The analytical values are shown in Tables 1 and 2.

[0031]

[Table 1]

[0032]

[Table 2]

Examples 1 to 5 and Comparative Examples 1 and 2 The epoxy resins obtained in Reference Examples 2 to 8 were blended with dicyandiamide and 2-ethyl-4-methylimidazole in the proportions shown in Tables 3 and 4 to obtain resins. 30 parts by weight of methyl ethyl ketone was added to 70 parts by weight of the solid content and dissolved to obtain a resin varnish. Glass varnish (Kanebo Co., Ltd.)
(Product name: KS-1600, treated with epoxysilane)
Was impregnated with the solution and dried in a hot air dryer at 180 ° C. for 8 to 15 minutes to obtain a prepreg. However, with respect to the resin of Reference Example 8, superscript was observed during impregnation, and foaming occurred during drying.
Therefore, 40 parts by weight of methyl ethyl ketone is added to 60 parts by weight of resin solids and dissolved to form a resin varnish,
Impregnate the glass cloth for another 15 minutes at 160 ℃
It was dried at 0 ° C for 15 minutes to obtain a prepreg.

Six pieces of prepreg and copper foil (manufactured by Furukawa Circuit Foil Co., Ltd., TTAI treated, 85 μ thick) were superposed, and press-formed at 160 ° C. under a pressure of 50 kg / cm ² for 90 minutes, and then copper-clad with 1 mm. A laminated board was obtained. The results of measuring the physical properties of the laminate are shown in Tables 3 and 4.

Comparative Example 3 Brominated bisphenol A type epoxy resin (trade name: Sumiepoxy ESB-500, epoxy equivalent 472 g / equivalent, manufactured by Sumitomo Chemical Co., Ltd.) 90 g, o-cresol novolac type epoxy resin (trade name: Sumiepoxy) ESC
N-220F, an epoxy equivalent of 215 g / equivalent, 10 g of Sumitomo Chemical Co., Ltd., dicyandiamide, and 2-ethyl-4-methylimidazole were mixed, and a laminated plate was obtained in the same manner as in Example 5. The evaluation results are shown in Table 3. The resin viscosity was 480 cps.

[0036]

[Table 3]

[0037]

[Table 4]

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Yoichi Ueda 6 Kitahara, Tsukuba, Ibaraki Prefecture Sumitomo Chemical Co., Ltd. (72) Inventor Shuichi Kanagawa 6, Kitahara, Tsukuba, Ibaraki Sumitomo Chemical Co., Ltd.

Claims (2)

[Claims] 1. A pre-reaction of (A) at least one difunctional epoxy resin, (B) polyfunctional epoxy resin, (C) tetrabromobisphenol A and (D) diglycidyl ether compound of tetrabromobisphenol A. A flame-retardant epoxy resin composition containing the obtained adduct and an epoxy curing agent as essential components. 2. A polyfunctional epoxy resin is represented by the following chemical formula 1. (In the formula, R _{1 to} R ₅ are each independently a hydrogen atom, an alkyl group or an alkoxy group having 1 to 6 carbon atoms, X is independently a hydrogen atom, a chlorine atom or a bromine atom, and n is an average. The flame-retardant epoxy resin composition according to claim 1, which is an epoxy resin represented by the number of repeating units and a number of 1 to 6.).