JPH024888A - Adhesive composition - Google Patents

Abstract

PURPOSE:To provide the title composition giving both improved heat resistance and adhesive force at elevated temperatures, for use in metallic foils in laminates, comprising a blended epoxy resin, butyral resin, phenol-novolak resin oligomer and imidazole-based compound. CONSTITUTION:The objective composition can be obtained by incorporating pref. (A) 100 pts.wt. of an epoxy resin prepared by blending (1) a diphenylpropane novolak resin with (2) an epichlorohydrin-bisphenol in the weight ratio (1):(2)=(25:75)-(50:50) with (B) 20-40 pts.wt. of a butyral resin, (C) 25-45 pts.wt. of a phenol novolak resin oligomer and (D) an imidazole-based compound.

Description

[Detailed description of the invention] (Industrial application field) TECHNICAL FIELD This invention relates to adhesive compositions.

More specifically, the present invention relates to an adhesive composition for adhering metal foils to laminated plates, which can improve not only heat resistance but also adhesive strength at high temperatures.

(Prior art) In recent years, regarding metal-clad laminates used for printed wiring boards,
There is a need to improve the high temperature adhesion performance of metal foils.In order to improve the heat resistance of adhesives for this adhesion, adhesives based on epoxy resins have been widely used.

Such adhesives, for example, epoxy resin,
Products containing curing agents and curing aids are known.

(Problems to be Solved by the Invention) However, in the case of these conventional adhesives for bonding metal foils that are based on epoxy resins, although the heat resistance can generally be improved, the effect is insufficient. However, the adhesive strength of the metal foil at high temperatures was poor, and the adhesive strength at room temperature (normal state) also decreased.

It has been desired to solve these shortcomings as soon as possible.

This invention was made in view of the above circumstances, and it eliminates the drawbacks of conventional adhesives for bonding metal foils, has excellent heat resistance, and improves the adhesive strength of metal foils at high temperatures. The object of the present invention is to provide a new adhesive composition for adhering metal foils to laminates, which can be used to bond metal foils to laminated sheets.

(Means for Solving the Problems) In order to solve the above problems, the present invention provides an adhesive composition containing a butyral resin and an epoxy resin.
An adhesive composition for adhering metal foils to laminated plates, using a mixture of a diphenylpropane novolac type resin and an epichlorohydrin bisphenol type resin as an epoxy resin, and blending a phenol novolac resin oligomer and an imidazole type compound. This is what we provide.

There are no particular limitations on the type of butyral resin used in this composition, and any type of butyral resin can be used, including conventionally known ones. However, as the epoxy resin, diphenylpropane novolac type resin (A) A mixture with epichlorohydrin/bisphenol type resin (B) is used.

The types of both of these mixtures can be various, but the mixing ratio (A)/(B) of both is 20/80 to 60/40 by weight, particularly preferably 25
/75 to 50150.

The blending ratio of butyral resin and these epoxy resins can vary widely; however, for boat fishing,
It is preferable to use about 20 to 40 parts per 100 parts by weight of the epoxy resin. If the amount is too large, the adhesive strength at high temperatures will decrease, and if it is too small, the adhesive strength at normal conditions will decrease, which is not preferable.

The phenol novolak resin oligomer to be blended as a curing agent component is preferably used in an amount of 25 to 45 parts for boat fishing, based on 100 parts by weight of the above-mentioned epoxy resin.

Of course, this blending amount is not limited and can be changed as appropriate depending on the type of oligomer used.

Imidazole compounds include conventionally known ones, as well as optional devices such as aliphatic groups and aromatic groups as curing aids.
A compound having 6 groups can be used, and can be used in an amount of about 0.15 to 0.75 parts per 100 parts by weight of the epoxy resin.

The adhesive composition containing the above components is made into a resin liquid using a predetermined amount of methyl ethyl ketone, toluene, methanol, etc. as a solvent. In this case, the viscosity of the resin liquid is usually preferably about 500 to 1500 CtlS (25°C).

To adhere the metal foil to the laminate, add this resin liquid, for example 1
It is applied to a metal foil of copper, aluminum, iron, etc. to a thickness of about 5 to 45 μm, and dried at a temperature of 140 to 160° C. for about 2 to 6 minutes. The amount of resin applied is generally 20 to 50 t/ci, more preferably 30 to 40 g in the case of copper foil.
Adjust so that /-.

This is heated by placing it on a resin-impregnated base material laminate in which a base material such as glass cloth, glass cloth, or paper is impregnated with a resin such as phenol resin, epoxy resin, polyamide resin, or unsaturated polyester resin. Pressure to bond 0 Normally, at a temperature of about 150 to 180°C, 20 to 8
Pressurize at a pressure of 0 k+r/d.

(Function) In the adhesive composition of the present invention, by blending a mixed epoxy resin, a butyral resin, a phenol novolac resin oligomer, and an imidazole compound,
The solder heat resistance has been improved from the conventional 25 to 30 seconds to 35S.
eC or more, and the adhesive strength at high temperatures can be improved to more than three times that of conventional adhesives. Furthermore, the adhesive of the present invention also suppresses a decrease in adhesive strength at room temperature (normal state).

(Example) Next, Examples will be shown and the adhesive composition of the present invention will be explained in more detail.

Example 1 An adhesive composition having the following formulation was prepared.

(1) Butyral resin 30 (g) (
Manufactured by Denki Kagaku Kogyo Co., Ltd.: 6000C) (2) Epoxy resin 100 (A)
Diphenylpropane novolac type resin (30) (manufactured by Yuka Shell Co., Ltd.: Epi:1-toE-157)fB)
Epichlorohydrin/hisphenol type resin (70) (manufactured by Yuka Shell Co., Ltd., E-1001) (3) Phenol novolak resin oligomer 30 (manufactured by Mitsubishi Yuka Co., Ltd.: rlesin X-H) (4) Imidazole compound 0.3 (Shikoku Co., Ltd.) A resin solution (manufactured by Kasei Co., Ltd.: 2E4M2) having a viscosity of 700 CDS (25°C) by adding a solvent was applied to a copper foil and dried at 150°C for 3 minutes.

A coated resin amount of 30 g/aa was grown in pure phenol resin vapor, heated and pressurized to obtain a copper-clad laminate.

Please evaluate the solder heat resistance and copper foil adhesion strength of this laminate. Table 1 shows the results.

The solder heat resistance (260℃) is 30 to 40SeC, which is much higher than the 25 to 30 seconds of conventional products.
The adhesive strength at 150°C is also 0.90 to 1.101qr/
(2), which is far superior to the conventional 0.2 to 0.4 2/clI. Further, no decrease in adhesive strength was observed under normal conditions (room temperature).

Example 2 An adhesive resin composition was prepared in the same manner as in Example 1 except that the mixing ratio of epoxy resins (A) and (B) was 50150, and was used for adhering copper foil.

As shown in Table 1, the adhesive strength at high temperature (150°C) is 0.
93~1.06kg/clI, heat resistance is 38~4
It was 5 seconds.

Example 3 Copper foil was bonded in the same manner as in Example 1 except that the amount of phenol novolak resin oligomer was changed to 35.

As shown in Table 1, the adhesive strength at high temperature (150°C) is 0.
．． It was 95 to 1.05 kg/c.

Table 1 Comparative Example 1 Copper foil was bonded in the same manner as in Example 1 using only the (A) II resin of Example 1 as the epoxy resin. In this case, the heat resistance is 25-32 sec, and high temperature (150℃
), the adhesive force was only 0.3 to 0.4 kf/am.

Comparative Example 2 Copper foil was bonded in the same manner as in Example 1 without blending the phenol novolak resin oligomer.

Heat resistance is 25~30311IC, high temperature (150°
The adhesive force in case C) was only 0.2 to 0.4 kg/am.

Comparative Example 3 When copper foil was bonded in the same manner as in Example 1 without blending the imidazole compound, the bonding strength at high temperature (150° C.) was only Q, 3-0, 5kr/CI+.

(Effects of the Invention) According to the present invention, an adhesive composition for bonding metal foil can be obtained which has excellent heat resistance and has significantly improved adhesive strength at high temperatures of about three times or more than that of conventional products.

Further, this composition has good adhesive strength at room temperature (normal state).

Claims (4)

[Claims] (1) In an adhesive composition containing a butyral resin and an epoxy resin, a mixture of a diphenylpropane novolac type resin and an epichlorohydrin bisphenol type resin is used as the epoxy resin, and a phenol novolac resin oligomer and an imidazole type compound are blended. An adhesive composition for adhering metal foil to laminated plates, characterized in that: (2) The adhesive composition according to claim (1), which contains 20 to 40 parts of butyral resin per 100 parts by weight of epoxy resin. (3) A claim in which the diphenylpropane novolac type epoxy resin and the epichlorohydrin/bisphenol type epoxy resin are blended in a weight ratio of 25/75 to 50/50 (
1) Adhesive composition as described. (4) The adhesive composition according to claim (1), wherein 25 to 45 parts of the phenol novolac resin oligomer is blended to 100 parts by weight of the epoxy resin.