JPS60155440A - Making method of laminated board - Google Patents

Abstract

PURPOSE:To prevent possible void by a method wherein a base material impregnated with an insaturated resin varnish blended with a specified amount of an epoxy resin is used to form a belt-shaped laminated body, which is hardened by press molding after half-hardened without pressure applied. CONSTITUTION:A thermosetting insaturated resin is blended with an epoxy resin at a rate of 30-97wt% in the total to prepare an insaturated resin varnish. A base material such as glass cloth and glass paper or glass cloth and paper is impregnated with the insaturated resin varnish thus obtained and the resin-impregnated base material thus obtained is used to mold a belt-shaped laminated body. The laminated body is being transferred to be half-hardened without pressure applied and then, hardened by a press molding to obtain a laminated board. The insaturated resin available is insaturated polyester resin, diallylphthalate resin or the like and is diluted with vinyl monomer or the like to make a resin varnish with the addition of a polymerization initiator such as benzylperoxide.

Description

[Detailed description of the invention] 〔Technical field〕 The present invention relates to a method for manufacturing an electrical laminate.

[Background technology]

The following method has been developed as a continuous forming method for laminates used for electrically insulating substrates, etc. That is, an unsaturated resin having an unsaturated bond such as an unsaturated polyester resin, diallyl phthalate resin, or vinyl ester resin is diluted with a vinyl monomer (crosslinking agent), etc., and a polymerization initiator is further added to form an unsaturated resin liquid (varnish). This is then impregnated into a base material such as a strip of paper or glass cloth to create a resin-impregnated base material in succession.Next, this resin-impregnated base material is transferred and stacked in multiple layers, and then the resin-impregnated base material is layered as needed. Accordingly, a strip-shaped laminate is continuously created by overlapping strip-shaped copper foil, release film, etc. while transferring them.Then, this laminate is heated under no pressure using a heating furnace while transferring it (non-pressure forming). ).In this method, the laminates are manufactured continuously by heating and hardening them under no pressure, instead of applying heat and pressure to the laminates by putting them in a press one by one. Production efficiency is high because it is a manufacturing method that involves the production of unsaturated resins.Also, when manufacturing unsaturated resin varnishes, the varnish is made by diluting the unsaturated resin with a crosslinking agent rather than diluting it with a solvent, so the solvent It is also superior in terms of resource saving, as there is no need to use

However, the laminate obtained by this method had weak glabella adhesion and was unsatisfactory as an electrical laminate. Therefore, in order to improve such drawbacks, a method of using an epoxy resin as the unsaturated resin or a method of using an epoxy resin and a polyester resin in combination has been considered. However, when an epoxy resin is used alone, the viscosity of the resin is too high, resulting in problems with impregnating properties, and the reaction rate is slow, making it impossible to increase the line speed.

In addition, even when epoxy resin and polyester resin are used together, the curing of the blended epoxy resin is still slow, so after-curing in a thermosetting oven is required, and there are disadvantages to the pressureless continuous molding method. Some void defects,
Problems such as poor surface smoothness and plate thickness accuracy remain.

[Purpose of the Invention] The present invention was made in order to solve these problems, and the present invention has been made to provide a material that has excellent adhesion between the eyebrows, no void defects, and excellent surface smoothness and plate thickness accuracy. The purpose is to provide a method for manufacturing laminates.

[Disclosure of the invention]

In order to achieve the above object, the present invention includes a thermosetting unsaturated resin and an epoxy resin in an amount of 30 to 97% by weight of the total of both.
A base material is impregnated with the mixed unsaturated resin varnish, and the obtained resin-impregnated base material is used to form a belt-shaped laminate, which is semi-cured under no pressure while being transferred, and curing is completed by press molding. The gist of this paper is the manufacturing method of laminates.

That is, the method for manufacturing a laminate according to the present invention uses an epoxy resin mixed with an unsaturated resin in an amount of 30 to 97% by weight based on the total resin amount as a resin varnish, and impregnates the base material with the resulting mixture. The resin-impregnated base material was formed into a strip-shaped laminate by the continuous molding method described above, and a semi-cured laminate was obtained.
This is cut as appropriate and press-formed to allow complete hardening. This produces a laminate with excellent adhesiveness, surface smoothness, and thickness accuracy. less than,
This invention will be explained in detail.

Suitable substrates include glass cloth and glass paper, glass cloth and paper, etc. containing glass cloth. With other base materials, it is difficult to satisfy various conditions such as moisture resistance and dimensional stability required for electrical laminates.

As the unsaturated resin, unsaturated resins having unsaturated bonds such as unsaturated polyester resins, diallyl phthalate resins, and vinyl ester resins are used, which are diluted with vinyl monomers (crosslinking agents), etc. A polymerization initiator is added to form an unsaturated resin varnish.

The epoxy resin to be mixed into the unsaturated resin varnish is preferably low molecular weight and liquid. This epoxy resin is blended with a curing agent and a curing accelerator. The curing agent is preferably an acid anhydride, but some aromatic amines can be used. That is, hexahydrophthalic anhydride, methylnadic anhydride, diaminodiphenylmethane, 2-ethyl-4-methylimidazole, and the like. As the curing accelerator, tertiary amines such as benzoyldimethylamine and imidazoles are desirable.

The mixing ratio of the above-mentioned unsaturated resin and epoxy resin is, for example, polyester/epoxy = 70/30 to 3/97, and it is better to increase the ratio of the epoxy resin as much as possible.

Preferably, polyester/1,000 poxy=20/80-5
It is preferable to mix at a ratio of /95.

The manufacturing method of the laminate according to the present invention is different from the conventional method except that a predetermined amount of epoxy resin is mixed with the impregnated resin, and the semi-cured laminate is completely cured by press molding. It is similar to therefore,
For example, it is done as follows.

An unsaturated resin is diluted with a vinyl monomer such as styrene to a styrene content of approximately 40% by weight, a curing initiator is added to make a resin varnish, and this is a resin liquid made by adding a curing agent and curing accelerator to an epoxy resin (liquid). and mix to achieve the above mixing ratio. This resin varnish is applied while the glass cloth substrates supplied from a plurality of rolls sequentially pass through guide rolls. Excess resin is squeezed out of the resin-impregnated base material using a pair of upper and lower squeeze rolls.
They are stacked one on top of the other to form a strip-shaped laminate. This laminate is cured in a heating furnace or the like to become a semi-cured laminate.

Thereafter, a metal foil such as copper foil is attached to this laminate as necessary. Alternatively, before curing, metal foil with adhesive supplied by a laminating roll, or this and a release film are superimposed on the front and back of the strip-shaped laminate,
Thereafter, it is sent to a heating furnace or the like to become a semi-cured metal foil-clad laminate. Metal foil such as copper foil may be attached in a later pressing process.

In such a continuous molding method, lamination molding is generally performed under no pressure, but in the present invention, there is no problem even if the lamination molding is performed under some pressure by belt processing or the like. That is, it suffices if there is substantially no pressure.

The thus obtained semi-cured laminate or metal foil laminate is appropriately cut and heated and pressed using a forming press to completely cure and produce a product. Alternatively, the laminate can be semi-cured and then continuously pressed using a belt press or the like to be completely cured.

Examples of the present invention will be described below. Parts are parts by weight.

(Example 1) Unsaturated polyester resin (styrene content 40%,
7 parts of a resin solution containing 1% by weight of benzyl peroxide as a curing initiator and hexahydrophthalic anhydride were mixed into an epoxy resin (Epicoat 821) with a heat distortion temperature of 120°C.
) and 93 parts of a resin solution containing 0.5% by weight of benzyldimethylamine was used as a resin varnish.

This resin varnish was applied to a glass cloth (WE-1 manufactured by Nittobo Co., Ltd.).
16E-82) were impregnated and laminated using a normal continuous molding method, and cured at 110° C. for 7 minutes to obtain a semi-cured laminate. Copper foil was attached to both sides of this laminate, and it was molded by heating and pressing at a temperature of 175° C. and a pressure of 50 kg/c+J for 1 hour to obtain a copper foil laminate of Example 1.

The performance of this laminate, that is, the glabella adhesive strength, surface roughness, and void defects, are observed in Table 1 and compared with conventional examples (Example 2). Table 1 shows the epoxy resin formulation. Other than what is shown in
A copper-clad laminate having the same structure as the laminate of Example 1 was obtained under all the same conditions as in Example 1. The results are shown in Table 1.

(Example 3) The epoxy resin mixing ratio, formulation, and press molding conditions are shown in Table 1. The copper-clad laminate of Example 3 had a structure in which one glass cloth resin-impregnated base material was laminated on the top and bottom of a glass paper resin-impregnated base material, and copper foil was attached to the surface. And so. The results are shown in Table 1.

(Hereafter, extra white) Table 1 The abbreviations in Table 1 represent the following.

HHPA; Hexahydrophthalic anhydride NMA i Methyl nadic acid anhydride DDM Nidiaminodiphenylmethane BDMA, Benzyldimethylamine, 2F:4MZ; 2-Ethyl-4-methyl, thylimedalyl As shown in Table 1, In the laminate, good results were obtained in terms of interlayer adhesion strength, surface roughness, and void defects.

〔Effect of the invention〕

As seen above, in the method for manufacturing a laminate according to the present invention,
A predetermined amount of epoxy resin is mixed with the unsaturated impregnated resin, and the resulting semi-cured laminate is pressed and completely cured, resulting in high adhesive strength between the eyebrows and a smooth surface. It is possible to obtain a laminate with excellent properties and thickness accuracy, and without void defects.

Agent: Patent Attorney Takehiko Matsumoto

Claims (3)

[Claims] (1) A base material is impregnated with an unsaturated resin varnish made by mixing a thermosetting unsaturated resin and an epoxy resin in an amount of 30 to 97% by weight in total, and the resulting resin-impregnated base material is used to form a strip-shaped laminate. A method for manufacturing laminates in which the material is semi-cured under no pressure while being transferred, and the curing is completed by press molding. (2) The method for producing a laminate according to claim 1, wherein the base material contains at least a portion of glass cloth. (3) The method for manufacturing a laminate according to claim 1 or 2, wherein a low molecular weight, liquid epoxy resin is used as the epoxy resin.