JPS5955720A - Manufacture of laminated board - Google Patents

Abstract

PURPOSE:To obtain a laminated board by preventing a basic material from tearing in the time of molding, by accelerating curing reaction of impregnated resin which is in a state of not flowing or its resemblance by heating and pressing a prepreg under first impregnating and drying processes of resin to a basic material. CONSTITUTION:A prepreg is obtained by impregnating non-woven fabrics with epoxy resin varnish consisting of 100 weight parts epoxy resin, 3 weight parts curing agent of dicyandiamide and 0.2 weight parts accelerator of 2-methyl-4- methylimidazole and drying the same so as to get 60wt% resin quantity and 0% flow value, which is further impregnated with the epoxy resin and dried so as to get 75wt% total resin quantity and 20% flow value. A laminated board is obtained by laminating eight sheets of the prepregs which are heated and pressed for 30min at pressure of 60kg/cm<2> and temperature of 160 deg.C.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing a laminate that prevents substrate breakage during molding.

As is well known, the laminate is obtained by laminating prepregs obtained by impregnating and drying a thermosetting resin as a base material and heating and pressurizing the prepregs. For example, when a glass nonwoven fabric is used as a base material, if the degree of curing of the prepreg resin is low, the melt viscosity of the resin during molding will be low and there will be less base material breakage, but the thickness accuracy of the resulting laminate will be poor. On the other hand, if the degree of curing of the prepreg resin is too high, the melt viscosity of the resin increases during molding, which tends to cause the base material to break.

An object of the present invention is to provide a method for manufacturing a laminate that prevents the substrate from breaking during molding.

That is, in the manufacture of a laminate using prepreg obtained by repeating the resin impregnation and drying process twice into the base material as part or all of the base material, the prepreg is heated and pressurized in the first resin impregnation and drying process. It is characterized by proceeding with the curing reaction of the impregnated resin to a state where the resin does not flow, or is close to it, even if the resin does not flow. By curing the resin impregnated for the first time to the extent that it does not flow or hardly flows even when heated and pressurized, the fibers of the base material are reliably bonded, and the resin bonding between the fibers is bonded during molding. Since it is in a state where it does not flow or hardly flows, the strength of the base material is increased and breakage of the base material during molding is effectively prevented.

On the other hand, adhesion between the base material layers is ensured by the second impregnated resin.

Although the base material used in the present invention is not particularly limited, it is effective to apply the present invention to a glass nonwoven fabric that causes breakage of the base material. Glass nonwoven fabrics include those made by binding glass fibers using a water-based resin such as popal or epoxy resin as a binder, and those made by mixing cellulose fibers with glass fibers.

Furthermore, the thermosetting resin used in the present invention includes epoxy resin,
All thermosetting resins that can be used for laminates, such as phenolic resin, melamine resin, and polyester resin.
The resin used for the first impregnation and the resin used for the second impregnation may be different. Further, a prepreg that is cured to a state where the resin impregnated for the first time does not flow even when heated and pressurized, or is almost cured, may be used as appropriate for part or all of the prepreg constituting the laminate.

Next, the present invention will be explained in detail.

Example epoxy resin (EPON-1001, manufactured by Shell Chemical) 1
A glass non-woven fabric (EP-4475
, manufactured by Nippon Vilene) with a resin content of 60% by weight and a flow value of 0.
Impregnated and dried to a total resin content of 7%.
5% by weight, flow value 20%, and dried to obtain a prepreg. 8 sheets of the prepreg were laminated and the pressure was 6o.
xp/c! A laminate was obtained by heating and pressing at a temperature of 160° C. for 30 minutes.

In addition, the flow value is the flow value, where WI is the weight of the resin that flows out when nine sheets of prepreg (weight w0) of 9 m square are laminated and heated and pressurized at a pressure of 9/Cd and a temperature of 160°C. Value (96) = defined as 100 x 100.

Comparative Example Same as Example, except that resin f was used in the first impregnation and drying process.
A laminate was similarly obtained using eight sheets of prepreg having a f160 weight of 1% and a flow value of 596, and a second impregnation, and a drying process in which the total resin amount was 75% by weight and the flow value was 20%.

Conventional Example 1 Using the same face and base material as in Example, a laminate was similarly obtained using eight sheets of prepreg with a resin content of 75% by weight and a flow value of 20% in one impregnation and drying process.

Conventional Example 2 Same as Conventional Example 1, except that the resin amount is 75% by weight and the flow value is 1.
A laminate was obtained using eight sheets of prepreg with a concentration of 0%.

Table 1 shows the presence or absence of base material breakage, plate thickness accuracy, and performance of each of the laminates obtained above.

5-Table 1 The presence or absence of substrate breakage was visually determined. The plate thickness was measured at the X mark shown in the drawing, and its maximum value and equipment are shown in Table 1. Solder heat resistance and insulation resistance are JIS
- It was measured in accordance with -6911.

As is clear from Table 1, according to the present invention, it is possible to obtain a laminate with no breakage of the base material, small variations in plate thickness, and performance equivalent to that of the conventional one, and its industrial value is extremely high. It is a big thing.

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[Brief explanation of the drawing]

The drawing is an explanatory view showing the locations where the thickness of the laminate is measured. patent applicant 7- 129-

Claims (1)

[Scope of Claims] 1. In the production of a laminate plate that is laminated and molded using partially or entirely a prepreg obtained by repeating the steps of resin impregnation into the base material and drying twice, the first resin impregnation into the base material, A method for producing a laminate, which is characterized in that in the drying process, the curing reaction of the impregnated resin is advanced to a state where the resin does not flow or is close to flowing even when the prepreg is heated and pressurized. 2. The method for producing a laminate according to claim 1, wherein the base material is a glass nonwoven fabric. 3. The method for manufacturing a laminate according to claim 1, wherein the impregnating resin used for the 31st time is different from the resin used for the second impregnation.