JPS5857311B2 - Manufacturing method for metal foil-clad laminates - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing metal foil-clad laminates used for decoration, printed circuits, etc.

Recently, there has been a demand for inexpensive aluminum foil-clad laminates and rolled copper foil-clad laminates that are flexible and have high through-hole reliability.

Conventional metal foil-clad laminates using electrolytic copper foil, nickel foil, etc. are manufactured by layering metal foil on thermosetting resin prepreg, sandwiching it between mirror-finished stainless steel plates, and applying heat and pressure. It had been.

When a metal foil-clad laminate using aluminum foil or rolled copper foil, which has relatively low hardness, is molded using this method, gases generated from the metal foil during heating and pressure molding, such as attached moisture,
Volatile impurities or oils and fats become air bubbles and remain between the stainless steel backing plate and the metal foil, and the surface of the metal foil-clad laminate that is cooled and removed after hot-pressure molding is formed with concavities and completely damaged. It could not be put to practical use.

This phenomenon was often seen in the center of the metal foil-clad laminate, and it was found that it tended to become more pronounced as the molded size became larger.

The cause of this is that volatile substances generated from the metal foil during hot-pressure molding or gas generated from the lower prepreg through pinholes in the metal foil concentrate in the low-pressure area between the metal foil and the plate. Therefore, when hard metal foil is used, the volatile substances or gases can escape and disperse to the outside along the minute scratches on the metal foil or mirror-finished backing plate. Although this is unlikely to occur, if soft metal foil is used, the metal foil will adhere to the mirror-finished backing plate, and volatile substances or gases will be sealed between the metal foil and the backing plate. It is thought that the soft metal foil is pushed down by the expansion during heating, and the lower part of the metal foil sinks into the temporarily softened prepreg during the hardening process, creating a concave portion on the surface of the metal foil.

In order to eliminate the aforementioned drawbacks, the metal foil was
A method of preheating at 0°C to remove moisture and volatile substances adhering to the metal foil is considered, but there are drawbacks such as oxidation of the metal foil and the inability to treat the metal foil with adhesives due to preheating. .

Also. It has been difficult to obtain a metal foil-clad laminate without recesses even by considering the cushioning material used during molding or adjusting the timing of heating and pressurization.

An object of the present invention is to easily manufacture and provide to the market a metal foil-clad laminate that has an aesthetic surface without recesses even when using aluminum foil or rolled copper foil, which have relatively low hardness. It is something.

In order to achieve the above object, the present invention, as shown in Fig. 1, overlaps a metal foil 2 on a prepreg 1 whose base material is impregnated with a thermosetting resin, and heats and presses it to form a metal foil-clad laminate. During manufacturing, the metal foil 2 comes into contact with a stainless steel backing plate 3 that has been subjected to fine scratch processing on its entire surface, and the side of the prepreg 1 that does not overlap the metal foil 2 comes into contact with a stainless steel backing plate 4 that has a normal mirror finish. The metal foil clad laminate 5 shown in FIG. 2 is obtained by inserting this into a press, heating and pressurizing it, and in particular dispersing and releasing volatile substances as mentioned above to the outside. In order to achieve this, the metal foil-clad laminate is manufactured by using a stainless steel backing plate whose entire surface is subjected to fine scratch processing instead of the conventional mirror-finished stainless steel backing plate.

In carrying out the present invention, the metal foil is aluminum foil, rolled steel foil, etc., which have relatively low hardness, and the scratch-treated stainless steel backing plate is a commercially available mirror-finished stainless steel backing plate. You can use one that has been treated with 1000 grit sandpaper to give it fine irregularities.

It was a cabinet. When used for decoration, sandpaper (e.g. #400 or =
#800) can also be used.

Example 1 9 sheets of prepreg impregnated with phenol resin were stacked on a paper base material, a 50μ aluminum foil was stacked on top of this, and the entire surface was evenly scratched using #800 sandpaper so as to be in contact with the aluminum foil. 1, O
The stainless steel backing plate of rnArR is stacked, and on the prepreg side where the aluminum foil is not overlapped, a stainless steel backing plate with a conventional mirror finish is used, taking into consideration the releasability between the laminate and the backing plate and the gloss of the finished surface. This was stacked and inserted into a press, heated and pressed at a pressure of 100 kg/cd and a temperature of 160° C. for 1 hour, and then cooled to obtain an aluminum foil-clad laminate having a thickness of 1.6 rrym.

There were no recesses on the metal foil surface of this laminate, so it could be used for decoration without any problems, and the surface had a beautiful appearance.

Example 2 Prepreg made by impregnating a glass cloth base material with epoxy resin
Layer 20μ rolled copper foil on top of this.

Furthermore, the entire surface was uniformly scratched using #1000 sandpaper in contact with the rolled copper foil.
, 0rr 3A thick backing plates were stacked, and the prepreg side on which the rolled copper foil was not stacked was covered with a conventional stainless steel backing plate with a mirror finish, and the heating rate was 1.6 m3/fn under the same conditions as in Example 1.
A thick rolled copper foil clad laminate was obtained.

There were no recesses on the surface of the rolled copper foil of this laminate, and it could be used for printed circuits without any problems.

Reference example Nine sheets of prepreg impregnated with phenolic resin were stacked on a paper base material, and aluminum foil with a VC of 50μ was layered on top of this, and this composition was inserted into two mirror-finished stainless steel backing plates in the same manner as in Example 1. An aluminum foil-clad laminate having a thickness of 1.61% and 1 was obtained under the following conditions.

Several depressions were formed on the surface of the aluminum foil of this laminate, making it completely unusable.

As mentioned above, in manufacturing metal foil-clad laminates, the present invention uses a stainless steel backing plate that is in contact with the metal foil and has fine scratches on its surface. We were able to produce a metal foil-clad laminate that was capable of dissipating volatile matter to the outside and had no concave portions on the surface of the metal foil, causing no problems in practice.

I cut it. By changing the degree of scratching on the plate, it has become possible to produce a metal foil-clad laminate with a diffused reflection ratio on the surface of the metal foil, which is preferred for decorative purposes, by a simple method.

Furthermore, there is no need to dry the metal foil before molding, and the metal foil clad laminate has no depressions, even if there are pinholes and a few volatile stains on the surface of the metal foil, which are acceptable for decorative and printed circuit applications. can be produced, and its industrial value is great.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view showing the structure of manufacturing a metal foil-clad laminate according to the present invention, and FIG. 2 is a cross-sectional view of the metal foil-clad laminate obtained according to the present invention. 1 is a prepreg, 2 is a metal foil, 3 is a scratch-treated plate, 4 is a mirror-finished plate, and 5 is a metal foil-covered laminate.

Claims (1)

[Claims] 1. When producing a metal foil-clad laminate by layering aluminum foil or rolled copper foil on a prepreg whose base material is impregnated with a thermosetting resin, and sandwiching this between metal backing plates and applying heat and pressure, the metal foil covers the entire surface. The prebrig is configured so that it is in contact with a backing plate that is harder than the metal foil that has been subjected to fine scratch processing, and the side of the prebrig that does not overlap the metal foil is in contact with the backing plate that has been finished with a mirror finish, and this is inserted into a press and molded under heat and pressure. A method for manufacturing a metal foil-clad laminate, characterized by: