JPH0427005B2 - - Google Patents

Description

[Detailed description of the invention]

INDUSTRIAL APPLICATION FIELD The present invention relates to a method for manufacturing a laminate with improved thickness accuracy. Conventional technology Laminated boards are made by laminating prepreg obtained by impregnating and drying a thermosetting resin on a base material such as paper, cloth, glass cloth, glass nonwoven fabric, etc., sandwiching this between mirror plates, and forming it under heat and pressure. can get. Prepreg is made by sequentially impregnating and drying a thermosetting resin while transporting the long base material.The prepregs cut into predetermined dimensions are laminated in the same direction and heated and pressed. Molding is in progress. Problems to be Solved by the Invention In laminated molding, the resin in the prepreg flows and flows outward, so the formed laminate becomes thinner at the periphery than at the center, resulting in a deviation in plate thickness. (hereinafter referred to as "δ value") is also large at the periphery.
In terms of real numbers, the plate thickness accuracy is the average value (hereinafter referred to as “
value), the difference in thickness between the center and edge is 0.03
~0.05mm, and the δ value is 0.01mm or less at the center and 0.03-0.04mm at the edges. In such a situation, for a laminate plate with a thickness of 2 mm or less, if the value -3δ is taken, the plate thickness tolerance of ±10% will be exceeded, and defective products are very likely to occur. As long as the resin flows and flows outward, even if there remains a difference in thickness between the center and the periphery, the present invention suppresses the δ value in the periphery to a small value and improves the overall plate thickness accuracy without defective products. The purpose is to provide a good laminate. Means for Solving the Problems In order to achieve the above object, the present invention impregnates and dries a thermosetting resin while transporting a long base material,
When laminating prepregs cut to a predetermined size, the front and back sides are in the same direction, and the long base material is combined with one in the forward direction and the other in the opposite direction, and then heated and heated. It is press-formed. Function In the laminate manufacturing process, while the mechanical accuracy of the press equipment for heating and pressing and the thickness accuracy of the mirror plate are constant, the factors that most affect the thickness accuracy of the laminate are:
As a result of extensive research, it was found that this was due to variations in weight between the left and right sides of the prepreg (in the width direction of the long base material). In fact, when measuring the weight of a 10 cm square, it is 0.05 in the width direction.
There is a variation of ~1 g, which is caused by uneven resin viscosity and impregnation in the width direction of the substrate during impregnation with the thermosetting resin, and temperature differences in the width direction of the substrate during drying. In the present invention, the prepregs are laminated with the front and back sides in the same direction, and the front and back of the base material in the longitudinal direction are stacked in the forward direction and in the reverse direction, so the above-mentioned uneven weight between the left and right sides of the prepreg is alleviated. When the stacked prepreg structure is viewed as a whole, the weights of the left and right sides are averaged. As a result, the δ value of the thickness around the laminate can be suppressed to a small value. Embodiment Next, an embodiment of the present invention will be described together with a conventional example. A long paper base material with a width of 1050 mm is supplied in rolls.
While transporting this, it was impregnated with phenolic resin and dried, and cut into 1050 x 1050 pieces with a resin content of 45% by weight.
mm prepreg was obtained. This is the configuration shown in Table 1 ("Forward" means that the front and back in the longitudinal direction of the base material are in the forward direction, and "Reverse" means
(indicates the same and opposite direction), 6 sheets were laminated in a combination of forward and reverse directions (front and back are in the same direction), and the pressure was 100Kg/cm ²
It was molded under the conditions of heating for 90 minutes and cooling for 30 minutes.

【table】

[Table] The formed laminate was cut into a size of 1000 x 1000 mm and measured using a dial gauge with a thickness of 1/100 mm at 10 measurement points shown in Figure 2. Numbers 1 to 5 indicate measurement points at the ends of the laminate, and numbers 6 to 10 indicate measurement points at the center. The number of laminates measured was 10 in each example. The measured results are shown in Figure 1 in terms of values and δ values. In FIG. 1, when comparing the conventional example and the example, there is no noticeable difference in the δ value at the center of the laminate, but the δ value at the edge of the laminate is smaller in the example. It can be seen that the plate thickness accuracy at the edges has improved. In addition, Examples 1 and 3 have good workability in prepreg lamination work and are less likely to cause mismatching. Effects of the Invention As described above, in the present invention, when laminating prepregs, the front and back sides are in the same direction, and the front and back sides in the length direction of the base material are combined with one in the opposite direction and the other in the opposite direction. Its industrial value is that the weight variations on the left and right sides of the prepreg (in the width direction of the base material) are canceled out and averaged, and the thickness accuracy at the edges of the laminate can be improved in particular, thereby reducing thickness defects. It is extremely large.

[Brief explanation of drawings]

FIG. 1 is a comparison diagram of values and δ values at the center and end portions of the laminate, and FIG. 2 is an explanatory diagram showing the locations where the thickness of the laminate is measured.

Claims (1)

[Claims] 1. A method in which prepreg obtained by sequentially impregnating a long base material with a thermosetting resin and drying it while transporting it is cut into predetermined dimensions, and then laminating and molding the cut prepreg, in which the prepregs are laminated on the front and back sides. A method for manufacturing a laminate, characterized in that the processes are carried out in the same direction, and in which the longitudinal direction of the elongated base material is in the forward direction and in the reverse direction.