JP2954335B2 - Manufacturing method of laminated board - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention provides a laminate having good dimensional stability, small warpage, and small twist by reducing distortion generated during pressing.

[Conventional technology]

Conventionally, as a means for reducing distortion generated at the time of pressing, a method of reducing the maximum pressure of the press is mainly used. For this purpose, it is preferable to make the prepreg non-voided, but for this purpose, a large-scale facility such as a vacuum impregnating apparatus is required.
In the molding process, the use of a vacuum press is also effective,
This is also a large facility. It is also effective to heat to almost no pressure after normal pressing,
The number of processes increases.

[Problems to be solved by the invention]

An object of the present invention is to obtain a laminate having a small molding distortion, a small warp and the like, that is, a small dimensional changeability, using a usual coating machine and a press machine.

[Means for solving the problem]

The present invention is a method of laminating one or more prepregs obtained by impregnating a resin varnish into a substrate, arranging a metal foil on one or both sides as necessary, sandwiching these between metal mirror plates, and heating and pressing. In the method for producing a board, the pressure of the laminate is increased at a rate of 1 to 5 kg f / cm ² per minute for 5 minutes or more immediately after the gelling of the resin of the prepreg. is there.

The range of the boosting speed which is a feature of the present invention is 1 to 5 kg f / min.
cm ² , particularly preferably ² to 3 kg f / cm ² per minute. The time is at least 5 minutes or more, preferably 10 to 20 minutes, immediately after the resin of the prepreg is gelled.

[Action]

The pressurization method at the time of molding adopted in the present invention is not to lower the maximum pressure, but to pressurize to a required pressure while suppressing the occurrence of molding distortion, which may cause poor moldability due to insufficient pressure or the like. There is no.

Looking at the state of the prepreg and the molding pressure at the time of molding, (i) immediately after the start of molding, the pressure is such that the resin of the prepreg melts and flows and the air in the prepreg is discharged. It is necessary not to crush the roughened surface of the metal foil. Therefore, the pressure is 0.1-2kg f
/ cm ² is appropriate.

(Ii) The next step is to apply the pressure necessary to expel air that has penetrated deep into the substrate. At this stage, heat is sufficiently conducted. However, when the pressure is too high, the flow of the resin becomes large before the defoaming is performed efficiently, which causes a thickness defect of the laminate. The viscosity of the resin is recent during this stage. Considering these points, it is appropriate that the pressure is about 15 to 25 kg f / cm ² .

(Iii) In the stage where the curing of the resin further proceeds, the viscosity of the resin increases, and the pressure required for defoaming increases with time. An appropriate pressure is 15 to 30 kg f / cm ² .

However, after the gelation of the resin, the rapid pressure increase causes not only the failure of the plate thickness due to the movement of the resin but also the pulling of the base material outward, causing distortion.

In the stage after the gelation, when the pressure is applied according to the pressure increasing speed of the present invention, the balance between the curing shrinkage of the resin and the movement of the resin is balanced, and no distortion is generated between the base material and the resin. The required final pressure can be reached. It is desirable to keep the final pressure for 20 to 40 minutes so as not to cause molding defects.

〔Example〕

Under the conditions of the molding process shown in Table 1, a double-sided copper-clad epoxy resin glass woven laminate having a thickness of 1.6 mm was obtained.

The characteristics of the obtained laminates were measured, and Table 2 shows the results.

In the example, the same thing as the reference example using the vacuum press can be obtained, but in the comparative example, some characteristics are inferior to the example.

(Measurement method) Molding flow: The length and maximum value of the resin flowing out of the end face of the laminate after molding.

Appearance: After etching the copper foil, the surface appearance was visually observed.

Dimensional shrinkage: After etching the copper foil, heat treatment was performed at 170 ° C. for 30 minutes, and the shrinkage was determined from the difference from the dimension before the heat treatment.

Thickness accuracy: It was determined by dividing the difference between the maximum thickness and the minimum thickness by the maximum thickness.

〔The invention's effect〕

As is clear from the above examples, the laminate obtained by the present invention has particularly excellent dimensional stability, and also has excellent appearance and thickness accuracy.

──────────────────────────────────────────────────続 き Continued on the front page (58) Fields surveyed (Int. Cl. ⁶ , DB name) B29C 43/00-43/58 B32B 1/00-35/00

Claims (1)

(57) [Claims] 1. A prepreg obtained by impregnating a base material with a resin varnish is laminated one or more times, and if necessary, a metal foil is arranged on one side or both sides, and these are sandwiched between metal mirror face plates and heated and pressed. A method of manufacturing a laminated board, wherein the pressure of the laminated board is increased at a rate of 1 to 5 kg f / cm ² per minute for at least 5 minutes immediately after gelling of the resin of the prepreg. .