JPH01216831A - Laminated board - Google Patents

Abstract

PURPOSE:To obtain a laminated board having a dimensional stability, excellent folding property and bending elastic coefficient for mounting parts by integrating in one body the sheet comprising only a resin on both surfaces of the layer impregnated with resin into a sheet-shaped glass fibre basement. CONSTITUTION:The sheet 2 comprising only a resin is integrated in one body on both surfaces of the layer impregnated with resin into the sheet shaped glass fiber basement. The stress distribution in folding the laminated board is separated into the tensile stress 8 and the compression stress 4 at the protrusive side and the recessive side of fold on the boundary of a center line 5, and the closer the surface of the laminated board, the larger the respective stresses. Accordingly, it is a preferable constitution for folding property that the glass fibre basement 1 impregnated with a resin and not suitable for bending is arranged on the central part wherein the stress is small and the resin sheet 2 suitable for folding is arranged on both surface thereof. And the dimensional stability is good by the existence of the glass fibre basement 1 and the bending coefficient is sufficient for loading parts.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a bendable laminate suitable for use in printed wiring boards.

2. Description of the Related Art Conventionally, flexible wiring boards and lead wires with connectors have been used in electronic equipment to connect a plurality of rigid printed wiring boards incorporated therein. However, connecting and wiring them requires a large number of man-hours, and wiring errors are likely to occur.

In order to solve this problem, a flexible laminate in which a glass fiber-containing polyester nonwoven fabric base material is impregnated with an epoxy resin is known (Japanese Patent Laid-Open No. 184587/1987).

However, since this material contains polyester fibers in the base material, it does not have sufficient dimensional stability and is not particularly suitable for use in high-density printed wiring boards. In addition, epoxy resin usually becomes hard when cured and is not suitable for bending.
There is no specific disclosure as to what kind of epoxy resin was used to make it bendable. Although it has good dimensional stability due to its low elongation rate, it is not suitable for bending.

In addition, sheet types made only of resin and those using film are good at bending, but have poor dimensional stability.
Since the bending modulus is small, when parts are mounted on it, it deflects greatly, which is a practical problem.

Problems to be Solved by the Invention In view of the above points, an object of the present invention is to provide a laminate having good dimensional stability and bendability, and a sufficient bending elastic modulus for mounting components.

Means for Solving the Problems In order to achieve the above object, the present invention has a structure in which sheets 2 made only of resin are integrated on both surfaces of a layer of a sheet-shaped glass fiber base material 1 impregnated with resin. was adopted.

action Figure 1 shows the stress distribution when the laminate is bent.

The stress distribution when the laminate is bent is divided into tensile stress 9 and compressive stress 4 on the convex and concave sides of the first bend, with the center line 5 as the border, and each stress increases as the surface of the laminate increases. becomes larger. Therefore, a resin-impregnated glass fiber base material 1, which is not suitable for bending, is arranged in the central part where the stress is small, and resin sheets 2, which are suitable for bending, are arranged on both surfaces thereof. has an ideal configuration for bendability, which is the objective of the present invention.

Further, due to the presence of the glass fiber base material 1, the dimensional stability is good and it has a bending elastic modulus that can accommodate parts mounting.

EXAMPLE The sheet-like glass fiber base material used in the present invention is one commonly used for electrical insulation, and may be either a woven fabric or a non-woven fabric.

In the present invention, the resin impregnated into the glass fiber base material and the resin used in the resin sheet include thermosetting resins such as epoxy resin, polyester resin, and polyimide resin.
It may also be a thermosetting resin. Further, the resin impregnated into the glass fiber base material and the resin used for the resin sheet may be the same or different. As for the resin sheets, there is no problem even if a plurality of resin sheets of different types are used.

Example 1 100 parts by weight of epoxy resin (trade name: Epicoat 1001, manufactured by Yuka Shell), 3 parts by weight of dicyandiamide, and 0.5 parts by weight of benzyldimethylamine were blended, and this was impregnated into a glass fiber woven fabric base material. After drying, a prepreg (A) having a resin content of 40% was obtained. A sheet of polyimide resin with a thickness of 0.2 mm and a copper foil with adhesive (thickness of 2352 m) were placed on the upper and lower surfaces of the plastic plate (A),
A double-sided steel-clad laminate with a thickness of 0.6 mm was obtained by heating and pressurizing.

Example 2 A glass fiber non-woven fabric base material was used instead of the glass fiber woven fabric base material of Example 1, and a prepreg (B
) was obtained. A double-sided steel-clad laminate with a thickness of 0.6 mm was obtained using the prepreg (provided) and in the same manner as in Example 1 except for the above prepreg.

Comparative Example 1 Three sheets of prepreg were laminated, and steel foil with adhesive (
2352 m thick), heated and pressurized to a thickness of 0.6 m.
A double-sided copper-clad laminate of mm was obtained.

Comparative Example 2 Three sheets of prepreg (B) were laminated, steel foil with adhesive (thickness 2352 m) was placed on both surfaces, and the thickness was reduced to 0 by heating and pressurizing.
．． A 6 mm double-sided steel clad laminate was obtained.

Conventional Example 1 Adhesive-coated steel foil (thickness = 35 μm) was placed on both surfaces of a 0.6 plate sheet made of polyimide resin, heated,
Pressure was applied to obtain a double-sided copper-clad laminate having a thickness of 0.6.

Conventional Example 2 60 parts by weight of adipic acid was blended with 100 parts by weight of flame-retardant epoxidized dimer acid (epoxy equivalent: 400, manufactured by Dainippon Ink), and this was added to a glass fiber-containing polyester fiber nonwoven fabric base material (weight 35 cm). Impregnated, dried, prepreg (c
) was obtained. Three sheets of the prepreg (C) were laminated, adhesive-coated steel foil (thickness: 2352 m) was placed on both surfaces, and heating and pressure were applied to obtain a double-sided steel-clad laminate having a thickness of 0.6.

Examples 1-2, Comparative Examples 1-2, Conventional Examples 1-2 Test method Dimensional stability: Etching the entire surface of the copper foil of the laminate, E-0
, 5/150, the dimensional change from the normal state before the treatment was measured.

Flexural modulus: Based on JIS-G-6481.

Bendability: The laminate is bent 9 times along the curve of a cylindrical rod (choose one with a sufficiently small diameter so that no cracks occur in the laminate), and the laminate is held when the bending force is released. The radius of nine bends was measured.

Effects of the Invention As described above, the present invention has a structure in which sheets made only of resin are integrated on both surfaces of a layer of a sheet-like glass fiber base material impregnated with resin, which improves dimensional stability. The industrial value of this method is extremely great in that it is possible to obtain a laminate with a high flexural modulus that is both excellent and bendable.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram showing the distribution of bending stress when the laminate is bent, together with the structure of the laminate according to the present invention. 1 is a glass fiber base material, and 2 is a resin sheet.

Claims (1)

[Claims] 1. A laminate made by integrating sheets made only of resin on both surfaces of a layer made of a sheet-like glass fiber base material impregnated with resin. 2. The laminate according to claim 1, which has a metal foil integrated on at least one surface.