JP3252291B2 - Epoxy resin composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an FRP, particularly to a copper-clad laminate used for an electronic circuit board, which has low water absorption, excellent heat resistance and excellent adhesiveness, without impairing workability such as impregnation. It relates to the obtained epoxy resin composition.

[0002]

2. Description of the Related Art Epoxy resins are widely used in electronic parts, electric equipment, automobile parts, FRP, sporting goods, etc. because of their excellent adhesiveness, electric properties and heat resistance. However, copper-clad laminates used for FRP, especially for electronic circuit boards, are becoming thinner with increasing number of layers, and epoxy resins used for this purpose are required to have lower water absorption and higher heat resistance than ever before.

Conventionally, an epoxy resin used for an electronic circuit board is a brominated epoxy resin produced from tetrabromobisphenol A and epichlorohydrin or bisphenol A glycidyl ether, for example, Epototo YDB-400 (manufactured by Toto Kasei Co., Ltd.). Epoxy equivalent 380-420g / eq, bromine content 46-50wt
%), Epotote YDB-500 (epoxy equivalent 45
0 to 550 g / eq, bromine content 18 to 22 wt%) is used as a general-purpose product, and dicyandiamide alone or in combination with a polyamine compound as a curing agent, or a combination of a tertiary amine or imidazole as a curing accelerator. Used.

Meanwhile, as a method for reducing the water absorption of the epoxy resin and improving the heat resistance, a method for improving the purity of the epoxy resin is known. For example, there is a method of reducing a hydrolyzable chlorine component, an α-diol component or an unreacted phenol component, which are impurities contained in the epoxy resin, to the minimum. As this type of epoxy resin, for example, Epototo YDB-530 (epoxy equivalent 530 g)
/ Eq, bromine content 21.7 wt%), but there is a limit to the improvement in heat resistance.

Further, the present inventors have previously described that a brominated epoxy resin produced from tetrabromobisphenol A and epichlorohydrin or bisphenol A glycidyl ether has an average of 2.5 or more per molecule. With a compound having a phenolic hydroxyl group of 550 to 80
By using an epoxy resin obtained by reacting to be in the range of 0 g / eq, it is possible to reduce the compounding amount of a nitrogen-based curing agent component such as dicyandiamide, polyamine compound, etc., thereby reducing the water absorption. A method for reducing the amount has been found (see Japanese Patent Application No. 2-418195).

However, even in this method, when an epoxy resin having an epoxy equivalent of 800 g / eq or more or a resin having a high softening point of a compound having a phenolic hydroxyl group is used, the viscosity of the resin increases and the glass cloth Therefore, there is a limit to the improvement of the water absorption rate because the impregnation property of the resin deteriorates.

An epoxy resin obtained by simply polymerizing with bisphenol A or the like without using a compound having an average of 2.5 or more phenolic hydroxyl groups in one molecule has a high crosslinking density and heat resistance. It was found that not only was the water absorption reduced, but no improvement in the water absorption was observed.

As described above, the method of reducing the intramolecular impurities of the epoxy resin or the method of using the polyfunctional phenol compound has the advantage of reducing the water absorption of the epoxy resin and having excellent properties such as heat resistance and adhesiveness. There was a limit in obtaining the resin.

[0009]

The present inventor has made various studies to improve the above-mentioned disadvantages and obtain an epoxy resin having a low water absorption rate and excellent heat resistance and adhesiveness. Even if a phenolic compound is used, without affecting the impregnating properties, a method for reducing the curing agent component that causes the deterioration of water absorption has been found and the present invention has been completed, and the object of the present invention is to date. Impregnated with a novel epoxy resin composition for copper-clad laminates, which has a limit in the method of reducing such intramolecular impurities or the method of using a polyfunctional phenol compound, which has a limit in reducing water absorption and excellent heat resistance and adhesion. It is provided by a method that does not adversely affect workability such as workability.

[0010]

The gist of the present invention is to provide an epoxy resin composition comprising an epoxy resin and a curing agent, wherein the epoxy resin has an average of 2.5 or more phenolic hydroxyl groups in one molecule. Epoxy compound obtained by reacting a compound having the compound, tetrabromobisphenol A or bisphenol A with a low molecular weight epoxy resin has an epoxy equivalent of 300
An epoxy resin composition characterized in that the epoxy resin composition has a range of from 700 g / eq to 700 g / eq and a residual phenolic hydroxyl group equivalent of from 500 to 3000 g / eq. That is, in the present invention, by using the specific epoxy resin described above, it was possible to provide an epoxy resin excellent in workability such as low water absorption, heat resistance, excellent adhesion and impregnation. .

In one molecule used in the present invention, the average is 2.
Examples of the compound having 5 or more phenolic hydroxyl groups include phenol and cresol, bisphenol A, phenol novolak resin having 2.5 or more functional groups obtained by condensation of phenols and aldehydes represented by bisphenol F, phloroglucinol, Modified phenol compounds having a functionality of 2.5 or more represented by polyparavinylphenol, tetraphenylolethane, a reaction product of an unsaturated compound and a phenol, and their halides are exemplified. Specifically, a compound having about 3 to 7 phenolic hydroxyl groups per molecule is preferable.

As the low molecular weight epoxy resin, bisphenol A, tetrabromobisphenol A, bisphenol F, biphenyl, hydroquinone, 9,9-bis (4
Epoxy resins produced from bifunctional or more functional phenols represented by (-hydroxyphenyl) fluorene, phenol novolak and the like and epihalohydrin. And the epoxy equivalent of this epoxy resin is 11
It is about 0 to 400 g / eq.

Further, in the present invention, tetrabromobisphenol or bisphenol A is reacted with a compound having a phenolic hydroxyl group and a low molecular weight epoxy resin. The reason is that only polyfunctional phenols and low-molecular-weight epoxy resin cause gelation during synthesis, and gelling can be prevented by using tetrabromobisphenol or bisphenol A in combination. Further, it is possible to obtain a balance between the peel strength with a copper foil when formed into a laminate, heat resistance, and flow characteristics during press molding.

In the present invention, the compound having a phenolic hydroxyl group is reacted with a low-molecular-weight epoxy resin and bisphenol A or tetrabromobisphenol A so that the epoxy equivalent is in the range of 300 to 700 g / eq, and Phenolic hydroxyl equivalent is 500 ~
Although an epoxy resin in a range of 3000 g / eq is obtained, a known catalyst can be used in the reaction. Conventional catalysts such as metal oxides, inorganic bases, organic bases and salts thereof, onium compounds and phosphines may be used.

However, in the present invention, in order to leave a specific amount of phenolic hydroxyl groups in the epoxy resin partially unreacted, it is necessary to adjust the amount of the catalyst, the reaction temperature and the like variously depending on the raw materials used. Also, with certain catalysts, the catalyst can be deactivated by various methods,
The desired epoxy resin can be produced by this method. As a method for deactivating the catalyst, there are methods such as lowering the reaction temperature, adding a deactivator, or raising the temperature to thermally decompose the catalyst.

The desired epoxy resin can also be produced by a continuous synthesis method represented by a mixing device such as a uniaxial co-kneader or a biaxial ruder. In short, any method may be used as long as the terminal groups of the epoxy resin are a specific number of epoxy groups and phenolic hydroxyl groups.

When the epoxy equivalent in the epoxy resin composition of the present invention is 300 g / eq or less, the amount of the curing agent used is large. As a result, the water resistance is inferior. The density decreases and the heat resistance deteriorates. When the residual phenolic hydroxyl group equivalent is 500 g / eq or less, the proportion of the modified phenol compound is reduced, and therefore, the heat resistance is reduced, and when it exceeds the range of 3000 g / eq,
The amount of the curing agent used increases, resulting in poor water resistance and poor impregnation.

As the curing agent of the composition of the present invention, a commonly used curing agent for epoxy resins such as a phenol curing agent and acid anhydrides and amines can be used. In terms of adhesiveness and heat resistance,
Dicyandiamide is used alone, in combination with a polyamine compound, or in combination with a tertiary amine or imidazole as a curing accelerator.

(Action) As a result of examining the hygroscopicity of the epoxy resin composition, when a nitrogen-based curing agent, particularly a dicyandiamide-based resin, is used, the smaller the epoxy equivalent of the resin is,
That is, it is known that the greater the amount of dicyandiamide used, the greater the water absorption. Therefore, if the epoxy resin is polymerized to increase the epoxy equivalent and the amount of the nitrogen-based curing agent used is reduced, the water absorption can be reduced. . Not only that, but also the water absorption rate becomes worse. For this reason, by using a compound having an average of 2.5 or more phenolic hydroxyl groups in one molecule and polymerizing it without lowering the crosslink density, it is possible to lower the water absorption and improve the heat resistance.

However, as the polymer becomes higher, the viscosity of the resin becomes higher, the impregnating property of the glass cloth becomes worse, and a good copper-clad laminate cannot be produced. Therefore, a specific amount of a phenolic hydroxyl group is left unreacted in the epoxy resin, and the reaction is stopped at a molecular weight at which the resin does not increase in viscosity. When the remaining phenolic hydroxyl groups act as a curing agent, the amount of dicyandiamide added as a curing agent is reduced. This reduces the water absorption,
The heat resistance can be maintained, the adhesive strength between the copper foil and the interlayer can be increased, and an epoxy resin composition having good impregnation with glass cloth can be obtained.

[0021]

Next, the present invention will be described in detail with reference to examples and comparative examples. The epoxy equivalent of the synthesized epoxy resin was measured according to JIS K7236. The phenolic hydroxyl equivalents of Synthesis Examples 1 to 3 were obtained by measuring the acid value with potassium hydroxide and converting the value to the phenolic hydroxyl equivalent.

Synthesis Example 1 In a four-necked flask equipped with a stirrer, a thermometer, a cooling tube, and a nitrogen gas introducing device, 550 parts of Epototo YD-128 (bisphenol A type epoxy resin epoxy equivalent of 186 g / eq, manufactured by Toto Kasei Co., Ltd.) , ZX-1236 (manufactured by Toto Kasei Co., Ltd., dicyclopentadiene-p-cresol condensate, 3 parts of phenolic hydroxyl groups in one molecule), and melted by heating while flowing a nitrogen gas, and then 0.1 part of triphenylphosphine Was added and reacted at 160 ° C. for 2.5 hours. Thereafter, 366 parts of tetrabromobisphenol A was added and melted. To this, 0.02 part of triphenylphosphine was added and reacted at 160 ° C. for 4 hours to obtain an epoxy resin. The epoxy equivalent of the obtained epoxy resin was 638.2 g / eq, and the phenolic hydroxyl group equivalent was 2562 g / eq.

Synthesis Example 2 The same operation as in Synthesis Example 1 was performed to melt tetrabromobisphenol A, and then the amount of triphenylphosphine added was reduced to 0.01 part. The reaction was carried out at 160 ° C. for 4 hours, and the epoxy resin was reacted. I got The epoxy equivalent of the obtained epoxy resin was 529.3 g / eq, and the phenolic hydroxyl group equivalent was 1403 g / eq.

Synthesis Example 3 YD-128565 using the same apparatus as in Synthesis Example 1.
And 70 parts of D-5 (orthocresol novolak resin, manufactured by Toto Kasei Co., Ltd., having 7 phenolic hydroxyl groups in one molecule and a softening point of 98 ° C.). The mixture was heated and melted while flowing a nitrogen gas. One part was added and reacted at 160 ° C. for 2.5 hours. Thereafter, 366 parts of tetrabromobisphenol A was added and melted to obtain an epoxy resin. The epoxy equivalent of the obtained epoxy resin was 407.3 g / eq, and the phenolic hydroxyl equivalent was 74.
It was 4.5 g / eq.

Synthesis Example 4 Using the same apparatus as in Synthesis Example 1, YD-128 590
, 28 parts of bisphenol A and 366 parts of tetrabromobisphenol A were charged and heated and melted. To this was added 0.5 part of triphenylphosphine and reacted at 160 ° C. for 4 hours to obtain an epoxy resin. The epoxy equivalent of the obtained epoxy resin was 709.4 g / eq.

Synthesis Example 5 YD-128 575 using the same apparatus as in Synthesis Example 1.
, 59 parts of ZX-1236, and 366 parts of tetrabromobisphenol A, and melted by heating. To this was added 0.5 part of triphenylphosphine and reacted at 160 ° C. for 4 hours to obtain an epoxy resin. The epoxy equivalent of the obtained epoxy resin was 694.1 g / eq.

Synthesis Example 6 Using the same apparatus as in Synthesis Example 1, YD-128 559
Parts, 76 parts of ZX-1236, and 366 parts of tetrabromobisphenol A, and melted by heating. To this was added 0.5 part of triphenylphosphine and reacted at 160 ° C. for 4 hours to obtain an epoxy resin. The epoxy equivalent of the obtained epoxy resin was 772.3 g / eq.

The epoxy resin obtained by the above-mentioned synthesis method was mixed with a curing agent, and a copper-clad laminate was manufactured using the obtained epoxy resin composition, and the laminate was evaluated. The copper-clad laminate was prepared under the following conditions. To each epoxy resin dissolved in methyl ethyl ketone, a curing agent dicyandiamide (manufactured by Nippon Carbide Industry Co., Ltd.) and a curing accelerator 2 ethyl 4 methyl imidazole (manufactured by Shikoku Chemical Industry Co., Ltd.) were added as a methyl cellosolve / dimethylformamide solution, Cloth (WEA-116E-105F115- manufactured by Nittobo Co., Ltd.)
N) and dried at 150 ° C. for 6 minutes to form a B-stage. 35 μm above and below this 4-ply prepreg ply
Copper foil (3EC manufactured by Mitsui Kinzoku Mining Co., Ltd.)
Molding was performed under the curing conditions of 70 ° C. × 20 kgf / cm ² × 2 hours to obtain a laminate having a thickness of 0.4 mm.

The evaluation method is as follows. The impregnating property was evaluated by visually impregnating a glass cloth with the compounded resin varnish. Those with very good impregnation are indicated by a, and those with slightly better impregnation are indicated by b. Further, those which were close to the limit in the ordinary impregnation method were indicated by c marks. The water absorption was measured by removing the copper foil by etching according to JIS C 6481 3.2, and then leaving it for 96 hours under the conditions of 90% humidity and 40 ° C. according to JIS C 5023, and measuring the water absorption from the weight change. did. For the measurement of the glass transition temperature, DMA 982 manufactured by DuPont was used, and the Tan δ value was measured using a horizontal clamp at a heating rate of 2 ° C./min. Copper foil peel strength is measured according to JIS C 6486.
Performed according to 7.7. The interlaminar bond strength was measured by measuring the bond strength between one layer on the surface of the glass cloth and the three lower layers in the same manner as the copper foil peel strength with the copper foil still attached.

Example 1 1.24 parts of dicyandiamide as a curing agent and 2 parts of a curing accelerator were added to 100 parts of the epoxy resin obtained in Synthesis Example 1.
0.15 parts of ethyl 4-methylimidazole was blended, and the laminate was evaluated. Table 1 shows the performance of the obtained laminate.

[0031]

[Table 1]

Example 2 To 100 parts of the epoxy resin obtained in Synthesis Example 2, 1.24 parts of dicyandiamide as a curing agent and 2 parts of a curing accelerator
0.15 parts of ethyl 4-methylimidazole was blended, and the laminate was evaluated. Table 1 shows the performance of the obtained laminate.

Example 3 1.17 parts of dicyandiamide as a curing agent and 2 parts of a curing accelerator were added to 100 parts of the epoxy resin obtained in Synthesis Example 3.
0.10 parts of ethyl 4-methylimidazole was blended, and the laminate was evaluated. Table 1 shows the performance of the obtained laminate.

Example 4 Epotote Y was added to 85 parts of the epoxy resin obtained in Synthesis Example 1.
DCN-704 (orthocresol novolak epoxy resin manufactured by Toto Kasei Co., Ltd., epoxy equivalent: 215 g / e
q) 15 parts were mixed, 1.78 parts of dicyandiamide as a curing agent, and 0.08 part of 2-ethyl-4-methylimidazole as a curing accelerator were blended, and the laminate was evaluated. Table 2 shows the performance of the obtained laminate.

[0035]

[Table 2]

Example 5 YDCN-7 was added to 85 parts of the epoxy resin obtained in Synthesis Example 2.
The mixture was then mixed with 1.15 parts of dicyandiamide as a curing agent and 0.08 parts of 2-ethyl-4-methylimidazole as a curing accelerator, and the laminate was evaluated. Table 2 shows the performance of the obtained laminate.

Example 6 YDCN-7 was added to 85 parts of the epoxy resin obtained in Synthesis Example 3.
04 parts were mixed, 1.72 parts of dicyandiamide as a curing agent, and 0.05 part of 2-ethyl-4-methylimidazole as a curing accelerator were blended, and the laminate was evaluated. Table 2 shows the performance of the obtained laminate.

Comparative Example 1 Epotote YDB-530 (a brominated epoxy resin manufactured by Toto Kasei Co., Ltd., epoxy equivalent 53, epoxy resin)
(0 g / eq) of 100 parts, 1.99 parts of dicyandiamide as a curing agent, and 0.10 part of 2-ethyl-4-methylimidazole as a curing accelerator were blended, and the laminate was evaluated. Table 3 shows the performance of the obtained laminate.

[0039]

[Table 3]

Comparative Example 2 1.48 parts of dicyandiamide as a curing agent and 2 parts of a curing accelerator were added to 100 parts of the epoxy resin obtained in Synthesis Example 4.
0.10 parts of ethyl 4-methylimidazole was blended, and the laminate was evaluated. Table 3 shows the performance of the obtained laminate.

COMPARATIVE EXAMPLE 3 1.51 parts of dicyandiamide as a curing agent and 100 parts of a curing accelerator were added to 100 parts of the epoxy resin obtained in Synthesis Example 5.
0.15 parts of ethyl 4-methylimidazole was blended, and the laminate was evaluated. Table 3 shows the performance of the obtained laminate.

Comparative Example 4 1.36 parts of dicyandiamide as a curing agent and 2 parts of a curing accelerator were added to 100 parts of the epoxy resin obtained in Synthesis Example 6.
0.15 parts of ethyl 4-methylimidazole was blended, and the laminate was evaluated. Table 3 shows the performance of the obtained laminate.

Comparative Example 5 YDCN was added to 85 parts of YDB-530 as an epoxy resin.
The mixture was mixed with 15 parts of -704, 2.42 parts of dicyandiamide as a curing agent, and 0.05 part of 2-ethyl-4-methylimidazole as a curing accelerator, and the laminate was evaluated.
Table 4 shows the performance of the obtained laminate.

[0044]

[Table 4]

Comparative Example 6 YDCN-7 was added to 85 parts of the epoxy resin obtained in Synthesis Example 5.
04 parts were mixed, and 2.02 parts of dicyandiamide as a curing agent and 0.08 part of 2-ethyl-4-methylimidazole as a curing accelerator were blended, and the laminate was evaluated. Table 4 shows the performance of the obtained laminate.

Comparative Example 7 YDCN-7 was added to 85 parts of the epoxy resin obtained in Synthesis Example 6.
The mixture was mixed with 1.15 parts of dicyandiamide as a curing agent and 0.08 part of 2-ethyl-4-methylimidazole as a curing accelerator, and the laminate was evaluated. Table 4 shows the performance of the obtained laminate. From the above results, the product of Example was good in all respects, but the impregnating property and the glass transition temperature were good in Comparative Example 1, but the water absorption was higher than Examples 1 to 3. Example 5 Good impregnation and glass transition temperature, but water absorption, copper foil peak
Inferior to Examples 4 to 6 in the adhesive strength and interlayer adhesive strength.

[0047]

As described above, on average in one molecule.
Using a compound having five or more phenolic hydroxyl groups, by using an epoxy resin having a specific range of epoxy equivalents and a specific range of residual phenolic hydroxyl group equivalents, without impairing workability such as impregnation, This has the effect that an epoxy resin composition having improved heat resistance, moisture resistance, and adhesiveness can be obtained.

──────────────────────────────────────────────────続 き Continued on the front page (58) Fields surveyed (Int. Cl. ⁷ , DB name) C08G 59/20-58/38 C08G 59/14 C08J 5/24 H05K 1/03

Claims (3)

(57) [Claims] 1. An epoxy resin composition comprising an epoxy resin and a curing agent, wherein the epoxy resin has a compound having an average of 2.5 or more phenolic hydroxyl groups in one molecule, and tetrabromobisphenol A or bisphenol. A and an epoxy equivalent obtained by reacting a low molecular weight epoxy resin are in the range of 300 to 700 g / eq, and the residual phenolic hydroxyl group equivalent is 500 to 3000 g / eq.
The epoxy resin composition characterized by being within the range of eq. 2. A compound having an average of 2.5 or more phenolic hydroxyl groups in one molecule is obtained by condensing phenols represented by phenol, cresol, bisphenol A and bisphenol F with aldehydes. Novolak resin, and phloroglucinol,
The epoxy resin composition according to claim 1, wherein the epoxy resin composition is a modified phenol compound having a functionality of 2.5 or more represented by a reaction product of a polyparavinylphenol, tetraphenylolethane, an unsaturated compound and a phenol, or a halide thereof. object. 3. The low-molecular-weight epoxy resin is bisphenol A, tetrabromobisphenol A, bisphenol F, biphenyl, hydroquinone, 9,9-bis (4-
The epoxy resin composition according to claim 1, wherein the epoxy resin composition is a reaction product of a bifunctional or more phenol selected from the group consisting of (hydroxyphenyl) fluorene and phenol novolak with epihalohydrin.