JPH03193317A - Manufacture of laminated sheet - Google Patents

Abstract

PURPOSE:To realize a certain fixed sheet thickness distribution and prevent door heat resistance and inferior surface roughness from developing by a method wherein the size of cushioning material, which is to be arranged between hot plate and mirror plate, is made to be equal to or smaller than the size of the mirror plate and, at the same time, larger than the size of the end product of laminated sheet and, in addition, the size of prepreg is made to be larger than that of the mirror plate and larger than that of the cushioning material by 5mm or more. CONSTITUTION:The size of cushioning material 12, which is to be arranged between hot platen 1 and mirror plate 13, is made to be smaller (preferably by 5 - 15mm) than or equal to the size of the mirror plate 13 and, at the same time, larger than the size of laminated sheet in the form of end product, which is obtained by cutting off ends after forming. Further, the sizes of prepreg 14 and of copper foil 15, which is placed on the prepreg 14, when necessary, are made to be larger than that of the mirror plate 15 and larger than that of the cushioning material 12 by extending each end of the prepreg and the copper foil by 5mm or more beyond each side of the mirror plate. At forming, the pressing force applied to the prepreg does not abruptly become zero at the position changing from the end of the mirror plate to its outside and decreases gradually at a certain falling rate. Accordingly, the efflux of resin in the prepregs is small and no thinning of the sheet thickness at the end of the prepreg occurs, resulting in developing almost no lowering of characteristics.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a method for manufacturing a printed circuit laminate with good thickness accuracy.

<Prior art> Conventionally, the thickness accuracy of printed circuit laminates has been improved by lowering the resin flow characteristics of the prepreg, or by using raw materials that are considerably larger than the size of the final product. However, these methods have drawbacks such as limited formulations and frequent waste of raw materials.

<Problems to be Solved by the Invention> As a result of various studies in order to improve the thickness accuracy of laminates, the inventor found that the relationship between the sizes of the cushioning material, mirror plate, and prepreg affects the thickness accuracy. I found out that there is
The present invention has now been completed.

An object of the present invention is to provide a laminate that has a constant thickness distribution necessary for fine patterns such as thin wire circuits, and that does not suffer from poor heat resistance or poor surface roughness due to areas with low resin content. be.

<Means for Solving the Problems> The present invention provides a method for manufacturing a laminate in which one or more prepregs impregnated with a resin varnish are stacked, sandwiched between metal mirror plates, and then heated and pressure-molded. The cushioning material placed between the hot plate and the mirrored plate is equal to or smaller than the mirrored plate, and larger than the final laminate product, and the prepreg is larger than the mirrored plate and at least 5 m larger than the cushioning material. This is a method for manufacturing a laminate.

The present invention will be explained using the drawings. FIG. 1 shows the configuration and laminated molding state of the conventional method, and FIG. 2 shows the case of the present invention.

In Fig. 1(a), the cushion material (2) is a mirror plate (
3), and the prepreg (4) has approximately the same size as the mirror plate (3). Copper foil (5)
When the prepreg (4) is placed, it is usually larger than the prepreg (4).

! In this case, when heated and pressurized from above and below, the resin of the prepreg (4) melts and flows out from its ends, as shown in Figure (b). As the pressure drops sharply to zero on the outside, the outflow of this resin is considerable, and the resulting laminate edges are thinner and have various effects due to insufficient pressure. This will result in deterioration of characteristics. Therefore, it is necessary to cut and remove that part, and the usable part becomes smaller.

The present invention is a method to eliminate these drawbacks.

In FIG. 2(a), the cushioning material 021 is placed between the heating plate (1) and the mirror plate 03), and the size of the cushion material 021 is smaller than or the same as that of the mirror plate 0, and the rear end of the molding is cut to make the final product. It has a shape larger than the size of the laminate made into a product, and furthermore, prepreg A4 and W4 foil 00 placed on it if necessary.
is larger than the mirror plate C, and larger than the cushion material 021 by 5 m or more on each side at each end surface. The copper foil 051 is usually made larger than the prepreg (b).

In the present invention, during molding, since the cushioning material is smaller than or equal to the size of the mirror plate and smaller than the size of the prepreg, the pressure applied to the prepreg suddenly decreases to zero from the end of the mirror plate to the outside. It never decreases, but decreases with a certain slope.

Particularly when the cushioning material is smaller than the mirror plate (preferably 5 to 15 cm on each side), the decreasing gradient of this pressing force is gradual.

Therefore, the outflow of the resin in the prepreg is small, the plate thickness at the end of the prepreg does not become thinner, and there is almost no deterioration in properties.

<Examples> The present invention will be described below with reference to Examples and Comparative Examples. Cushioning material, mirror plate, copper foil, and epoxy resin-impregnated glass cloth prepreg were used, and their sizes are shown in Table 1. These materials were set between the hot plates to form four sets of copper-clad laminates, and the hot plate temperature was 180°C, 50 kg/cj, 90
A double-sided copper-clad laminate with a thickness of 1.2 mm was obtained by heating and press molding for 1 minute. The thickness of the cushion material was set to 3 mm after being formed.

The obtained laminate was cut into a 510 m square, and the properties shown in Table 2 were obtained.

(Measurement method) Plate thickness accuracy: Draw a center line on the laminate, divide it into 8 equal parts between each of the 10 points from both ends, and measure the plate thickness at the resulting 9 equally divided points. , was calculated using the following formula.

It is a schematic cross-sectional view showing lamination molding in the case of the invention,
(a) shows the structure of the material, and (b) shows the molded state.

Surface smoothness: Measured using a surface roughness meter near the above 9 points, and the maximum value was determined.

Formability: The quality of formability was determined based on the appearance near the end of the laminate.

○: Good, embossed Δ Nigarasu cloth is observed.

×The embossed Nigarasu cloth is large.

<Effects of the Invention> According to the method of the present invention, not only the thickness accuracy of the laminate is good, but also the moldable range up to the edges can be widened.
Since the surface smoothness is also excellent, it is an excellent method for obtaining a laminate suitable for creating fine patterns.

Claims (1)

[Claims] (1) A cushion placed between a hot plate and a mirror plate in a laminate production method in which one or more prepregs impregnated with resin varnish are stacked, sandwiched between metal mirror plates, and then heated and pressed. A method for manufacturing a laminate, characterized in that the material is equal to or smaller than the mirror plate and larger than the final laminate product, and the prepreg is larger than the mirror plate and 5 mm or more larger than the cushion material.