JP2956378B2 - Epoxy resin composition, epoxy resin prepreg and epoxy resin laminate - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an epoxy resin composition, an epoxy resin prepreg and an epoxy resin laminate useful for printed circuit boards and the like.

[0002]

2. Description of the Related Art In general, epoxy resin laminates are prepared by dissolving a resin composition comprising an epoxy resin, a phenolic curing agent such as dicyandiamide or bisphenol A novolak, imidazole and, if necessary, a filler in a solvent to form a varnish. Is impregnated into a fiber base material such as a glass cloth, and heated to form a B-stage resin to obtain a prepreg, and a predetermined number of prepregs are stacked and heated and pressed.

[0003] It is known that in order to increase the heat resistance of an epoxy resin laminate, it is only necessary to reduce α-diol and chloride ions to reduce factors that hinder crosslinking. It is also known to increase the crosslinking density by increasing the amount of a curing agent or imidazoles (curing accelerator) to improve heat resistance.

[0004]

However, when the above two methods are combined, the usable life of the resin varnish and the prepreg becomes extremely short. One of the reasons is that the activity of imidazole increases due to low chlorine ionization and the reaction occurs at a low temperature.

In order to prevent this, a curing accelerator having a high potential which is not affected by chloride ions and the like is required. However, conventionally known and commonly used imidazoles and tertiary amines have a latent potential which is satisfactory. I have no sex.

An object of the present invention is to provide an epoxy resin composition having a high potential using a curing accelerator which is not affected by chloride ions and the like, and an epoxy resin prepreg and an epoxy resin laminate using the resin composition. It is the purpose.

[0007]

Means for Solving the Problems The present inventors have studied why it is difficult to improve the potential when using conventional imidazoles, and have found an imidazole that can solve the problem. The present invention is an epoxy resin composition comprising a dicyandiamide or phenolic curing agent and an imidal compound represented by the general formula (2).

[0008]

Embedded image (In Chemical Formula 2 , R ₁ and R ₂ are each independently hydrogen, an alkyl group or a phenyl group having 1 to 20 carbon atoms, and R ₃ is a carbon atom having 1 carbon atom.
To 3 alkyl groups, n = 1 and 2. However, imidazo
A methyl group may be present at the 4-position of the benzyl group. )

The imidazole compound of the present invention is obtained by reacting a bisphenol F type epoxy resin or a bisphenol A type epoxy resin with 2-methylimidazole, 2-phenylimidazole, 2-ethyl-4-methylimidazole and the like.

[0010]

Since the imidazole compound does not retain active hydrogen as can be seen from the structure, it is less affected by chloride ions and hydrogen chloride. Also, reactivity confirmation by a differential thermal analyzer or the like shows high potential such as starting the reaction at 100 to 120 ° C. Further, when the pyrolysis temperature was measured using a thermogravimetric analyzer, it was confirmed that decomposition started at around 350 ° C.

That is, the imidazole compound used in the present invention is 4-methylimidazole, 2-ethyl-4
-Methyl imidazole, 2-undecyl imidazole and very good thermal stability as compared with imidazole complexes. Therefore, even if it remains unreacted, the effect on the heat resistance of the resin and the molded article is extremely small. Also, the solubility in a solvent is easily dissolved in toluene, xylene, methyl ethyl ketone, acetone, 2-methoxyethanol and the like, and the workability is excellent.

[0012]

【Example】

Example 1 100 parts (parts by weight, hereinafter the same) of a brominated bisphenol A type epoxy resin (Epicoat 5046, trade name of Yuka Shell Epoxy Co., Ltd.) having a bromination ratio of 21% and an epoxy equivalent of 475, 3.5 parts of dicyandiamide, and 0.3 parts of a compound obtained by reacting bisphenol A type epoxy resin with 2-phenylimidazole is dissolved in a mixed solvent of methyl ethyl ketone and N, N dimethylformamide, and impregnated in a glass cloth having a thickness of 0.2 mm, It was dried at 170 ° C. for 5 minutes to obtain a prepreg having a resin amount of 45%. Four prepregs were stacked, and a copper foil having a thickness of 18 μm was stacked on and under the prepreg, and heated and pressed at 4 MPa and 170 ° C. for 80 minutes to obtain a copper-clad laminate.

Comparative Example 1 A copper-clad laminate was obtained in the same manner as in Example 1, except that 0.2 parts of 2-ethyl-4-methylimidazole was used as a curing accelerator.

Comparative Example 2 0.3% of 2-undecylimidazole was used as a curing accelerator.
A copper-clad laminate was obtained in the same manner as in Example 1 except for using some parts.

Table 1 shows the prepreg performance and laminate characteristics of Example 1 and Comparative Examples 1 and 2.
The test was conducted according to JIS after copper foil was etched. The gel time was 40 ° C, 70% R
It is a time-dependent change of the gel time when stored in H.

[0016]

[Table 1]

Example 2 Bisphenol A novolak type epoxy resin (Epiclon N-865, trade name of Dainippon Ink Co., Ltd.) 100 parts (parts by weight, the same applies hereinafter), bisphenol A novolak resin (Pryofen LF-346, Dainippon Ink) (Product name) 30 parts, tetrabromobisphenol A
(Fireguard 2000, trade name of Teijin Chemicals Limited) 45 parts, bisphenol A type epoxy resin and 2
0.3 parts of a compound obtained by reacting with phenylimidazole is dissolved in a mixed solvent of methyl ethyl ketone and 2-methoxyethanol, impregnated in a glass cloth having a thickness of 0.1 mm, and dried at 150 ° C. for 5 minutes. A prepreg having a resin amount of 50% was obtained. Eight prepregs were stacked on top of each other, and copper foil with a thickness of 18 μm was stacked on top and bottom of the prepregs.
It was heated and pressed at 0 ° C. for 90 minutes to obtain a copper-clad laminate.

Comparative Example 3 A copper-clad laminate was obtained in the same manner as in Example 2 except that 0.2 parts of 2-ethyl-4-methylimidazole was used as a curing accelerator.

Comparative Example 4 0.3% of 2-undecylimidazole was used as a curing accelerator.
A copper-clad laminate was obtained in the same manner as in Example 2 except for using some parts.

Table 2 shows the prepreg performance and laminate properties of Example 2 and Comparative Examples 3 and 4.
The test was conducted according to JIS after copper foil was etched. The gel time was 30 ° C, 70% R
It is a time-dependent change of the gel time when stored in H.

[0021]

[Table 2]

[0022]

According to the present invention, the heat resistance level of the epoxy resin laminate can be greatly improved, and the useful life of the prepreg has been extended.

──────────────────────────────────────────────────の Continuing on the front page (72) Inventor Toshiyuki Hibino 1500 Oji Ogawa, Shimodate City, Ibaraki Prefecture Inside the Shimodate Plant, Hitachi Chemical Co., Ltd. (72) Ikuo Sugawara 1500 Ogawa Ogawa Shimodate City, Ibaraki Prefecture (56) References JP-A-59-38235 (JP, A) JP-A-61-9439 (JP, A) JP-A-62-18421 (JP, A) JP-A-61-268721 ( JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) C08G 59/40-59/60 C08G 59/62 C08J 5/24 B32B 27/38

Claims (4)

(57) [Claims] An epoxy resin composition comprising an epoxy resin and dicyandiamide and an imidal compound represented by the general formula (1). Embedded image (Wherein R ₁ and R ₂ each independently represent hydrogen, an alkyl group having 1 to 20 carbon atoms or a phenyl group, and R ₃ represents 1 carbon atom.
To 3 alkyl groups, n = 1 and 2. However, imidazo
A methyl group may be present at the 4-position of the benzyl group. ) 2. The epoxy resin composition according to claim 1, wherein a phenolic curing agent is blended in place of dicyandiamide. 3. An epoxy resin prepreg obtained by impregnating a substrate with a varnish obtained by dissolving the epoxy resin composition according to claim 1 or 2 in an organic solvent, and drying. 4. An epoxy resin laminate obtained by laminating a required number of the epoxy resin prepregs according to claim 3 and heating and pressing.