JPH0341070B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing laminates that require highly uniform surface properties, such as copper-clad laminates for printed circuits and circuit laminates produced by additive processes.

The purpose is to prepare one sheet of prepreg obtained by impregnating and drying a laminate resin into a laminate base material.
Alternatively, when forming a laminate by heating and pressing a plurality of stacked laminates, resin (burrs) overflowing from the peripheral side, top surface, and bottom surface of the laminate may hit the peripheral edge of the surface of the laminate. A method for manufacturing a laminate having highly uniform surface properties, which completely prevents adhesion to a mirrored metal plate by means of a bonded or adhesive tape, and therefore prevents any burrs from adhering to the surface of the formed laminate. Our goal is to provide the following.

As shown in Fig. 1, the laminate is made by laminating a required number of prepregs 1, which are prepared by impregnating and drying a laminate resin into a laminate base material, and then sandwiching the laminate a between metal mirror plates 2 and forming the laminate under heat and pressure. However, since the periphery 4 of the end face of the laminate a remains open, the resin (burr) 3 melted and flowed out from the prepreg 1 adheres to and hardens on the periphery and side surfaces of the metal mirror plate, causing the laminate to deteriorate after forming. When the metal mirror plate is separated, the burrs 3 are destroyed and burrs including fine powder burrs remain on the peripheral edge and side surfaces of the metal mirror plate.

On the other hand, since metal mirror plates are used repeatedly industrially, if the metal mirror plates, which have hardened burrs attached to the peripheral edges and sides and are destroyed and remain in the form of fine powder, are used as they are for the next molding, these metal When a prepreg laminate is placed between mirror plates, fine powder burrs remaining on the periphery or part of the side surfaces of the metal mirror plate become trapped and formed between the top or bottom surface of the prepreg laminate and the metal mirror plate. . When the laminate is a copper-clad laminate, such burrs cause dents on the copper foil surface, making it impossible to create a normal circuit. Furthermore, when circuits are processed on the surface of a laminate such as a circuit laminate using the additive method, the burrs embedded in the laminate similarly make it impossible to create a normal circuit.

Conventionally, in an attempt to prevent the overflow of burrs to solve the above-mentioned problems, the heating fluidity of the prepreg is minimized as much as possible without causing whitening due to lack of fluidity of the resin for the laminate. Although such an adjustment method has been adopted, it has the drawback that it is difficult to completely prevent burrs from overflowing from the circumferential side. For the same purpose, there is a method of heating and press-forming the laminated material using spacers, but although it is effective in improving the accuracy of the thickness of the laminated plate, it does not completely prevent the overflow of burrs from the peripheral side. cannot be prevented. Furthermore, for the same purpose, there is a method in which some or all of the peripheral parts of the prepreg are heated and pressed to a state where the fluidity is lowered than the central part, but this method also depends on the accuracy of the thickness of the laminate. However, it cannot completely prevent burrs from flowing out from the circumferential side.

In addition, as a method for removing burrs attached to a metal mirror plate rather than preventing burrs from flowing out, industrially, there is a method of forcibly removing them by polishing with a sander or scraping with a metal piece. However, it is difficult to completely remove the burrs that adhere to the sides of the mirror plate, and conversely, the periphery of the mirror plate may be ground during repeated use, or the side surface of the mirror plate may be scratched. There were drawbacks such as the inclusion of

The method for manufacturing a laminate of the present invention completely eliminates the above-mentioned conventional drawbacks that occur during lamination heating and pressure molding in prepregs made of any combination of various laminate resins and various laminate base materials. This will solve the problem.

The present inventors applied tape to the peripheral edges of each of the uppermost and lowermost surfaces of a laminate made by laminating the required number of prepregs, and then heated the laminate by sandwiching it between metal mirror plates. By pressure forming, regardless of the amount of burrs flowing out from the circumferential side of the prepreg laminate, especially the burrs flowing out from the top and bottom surfaces of the laminate, these burrs are completely prevented from adhering to the metal mirror plate. Based on this knowledge, we conducted various studies and completed the present invention.

As shown in FIG. 2, the present invention uses a single tape 5 (see FIG. 3) having a continuous hole 6 near the center to form the prepreg laminate a when heating and press-molding the laminate. It is characterized in that it is brought into contact with or adhered to the peripheral edge portions of the uppermost and lowermost surfaces in advance and then heated and press-molded.

The resins for laminates used in the present invention include phenolic resin, melamine resin, urea resin, epoxy resin,
These include thermosetting resins in general, such as diallyl phthalate resin, unsaturated polyester resin, polyimide resin, and polybutadiene resin. The base material for the laminate includes fiber paper, cotton cloth, cotton nonwoven fabric, synthetic fiber cloth, synthetic fiber nonwoven fabric, asbestos cloth, asbestos paper, glass cloth, glass fiber nonwoven fabric, and the like. The tape that comes into contact with or adheres to the peripheral edges of the top and bottom surfaces of the prepreg laminate is paper tape, cotton, polyamide,
polyester, polyvinyl alcohol, glass,
These include tapes made of woven or non-woven fabrics such as asbestos, synthetic resin tapes such as polyamide, polypropylene, polyester, polyvinyl alcohol, etc., or metal foil tapes made of copper, aluminum, etc.

The perforated tape used in the method of the present invention includes two tapes that are in contact with or adhered to the peripheral portions of the uppermost and lowermost surfaces of the prepreg laminate, as described above, and the other end of both tapes. This corresponds to the case where they are pasted together or sewn together. However, when two tapes are completely joined together so as to completely isolate them from the outside, the resin that flows out from the peripheral side of the prepreg during molding will tear the tape irregularly and flow out, adhering to the mirror plate, and the present invention There is a possibility that the intended purpose may not be achieved.

In the case of the perforated tape used in the present invention, the resin from the peripheral side of the prepreg flows out through the holes.
This hole is away from the mirror plate, the resin is cooled by air, and there is no risk of it adhering to the mirror plate.

The holes in the tape also allow gas generated during molding to escape.

The method of the present invention is more efficient than the case where a normal tape is brought into contact with or attached to the top or bottom surface of a prepreg laminate, as well as the work of attaching the tape to the prepreg laminate and between the metal mirror plates of the prepreg laminate. Preparation work can be made easier.

The perforated tape can be brought into contact with or attached to the peripheral edges of the top and bottom surfaces of the prepreg laminate by applying an adhesive or adhesive to the tape in advance, or by applying an adhesive or adhesive to the prepreg. You can use any of the following methods, such as applying an adhesive in advance and pasting the tape, overlaying the tape on the prepreg and then heating the tape with high-frequency heating or an electric trowel to melt the resin for the prepreg laminate, or sewing it together with thread. be.

The preferred position for applying the tape on the top and bottom surfaces of the prepreg laminate is between the periphery and 3.0 to 30 mm inside of the periphery to prevent burrs from flowing out from the top and bottom surfaces of the prepreg laminate. .

The width of the tape is preferably 7.0 to 150 mm. Although the thickness of the tape is not particularly limited, it is preferably 0.01 to 0.20 mm.

Although the size of the hole in the tape is not particularly limited, it is preferably 1 to 10 mm in diameter.

If the amount of resin flowing out from the peripheral side of the prepreg is large, it is more preferable to maintain a gap between the side surface of the laminate and the perforated tape when attaching this perforated tape to the peripheral edge portions of the top and bottom surfaces of the laminate. .

The gap should preferably be large enough to keep the resin (burrs) that overflows from the sides within the gap, and the length from the sides to the tape folded part (center) is 2.
~50mm is preferred.

In order to reduce the overflow of burrs from the prepreg laminate, it is preferable to heat and press mold the periphery of some or all of the prepregs in a state where the heat fluidity is lower than that of the central part. It is more preferable to apply a tape to the prepreg laminate in such a state and then heat and pressure mold it. In this case, the order in which the tapes are attached may be before or after the treatment for reducing the heating fluidity of the peripheral area.

A method for reducing the heating fluidity of the peripheral portion of prepreg is described in detail in Japanese Patent Publication No. 11340/1983. It is more preferable to apply a curing accelerator suitable for each laminate resin to the surface of the perforated tape attached to the top and bottom surfaces of the prepreg laminate that is in contact with the prepreg. Furthermore, it is also preferable to apply a mold release agent to the surface of this tape opposite to the surface in contact with the prepreg.

It is most preferable that the tape 5 bonded to the peripheral edge portions of the uppermost and lowermost surfaces of the prepreg laminate be molded under heat and pressure so that a portion thereof overlaps the metal mirror plate 2 as shown in FIG. Furthermore, the method of the present invention can also be used for single-sided metal-bonded laminates.

By the method of the present invention, it is possible to easily remove burrs from the prepreg laminate circumferential side and the prepreg on the top and bottom surfaces of the laminate, which are generated during hot-pressure molding of all kinds of thermosetting resin laminates, onto a metal mirror-surfaced plate. High density,
It is extremely valuable for industrial production of laminates for high-precision circuit boards.

The invention will now be illustrated by examples.

Example 1 Varnish made of 50% toluene solution of resol type tung oil modified phenol resin weighed 140g/m ² and width 1000
It was coated on 52 mm kraft paper and dried at 130°C to obtain a prepreg with a resin content of 52% and a volatile content of 6%. After cutting this prepreg into a size of 1000 mm x 1000 mm, a 10 mm portion around the 4th periphery was heat-treated with hot air at about 200℃ for 3 minutes to lose the heating fluidity of the periphery, and 9 sheets of this treated prepreg were laminated. Then, the tape width is 50mm and the diameter is continuous to the center of the tape at the peripheral edge of the top and bottom surfaces of this prepreg laminate.
3.0 mm perforated tape was pasted on both the top and bottom surfaces up to a 15 mm point inward from the periphery.

The surface of this tape opposite to the surface in contact with the prepreg is coated with a mold release agent, and the surface in contact with the prepreg is coated with an adhesive and 4,4'-diaminodiphenylmethane. This taped prepreg laminate is slightly smaller than the prepreg size.
It was sandwiched between 2.0 mm thick metal mirror plates with dimensions of 990 mm x 990 mm, and heated and pressed at a temperature of 170° C. and a pressure of 100 Kg/cm ² for 55 minutes to obtain a 1.6 mm thick laminate. In this case, no burrs were attached to the peripheral edge of the metal mirror plate. For comparison, we stacked nine sheets of prepreg that had lost their fluidity when heated in the same peripheral areas as above, and then
It was sandwiched between metal mirror plates with dimensions of 990 mm x 990 mm and heated and pressed under the same conditions to obtain a 1.6 mm laminate. in this case,
Although there was almost no overflow from the peripheral side of the laminate, burrs were attached to the periphery of the metal mirror plate due to a slight overflow of burrs from the top and bottom surfaces of the prepreg.

[Brief explanation of the drawing]

Figure 1 is a cross-sectional view of the conventional method;
The figure is a sectional view of a laminate plate formed by the method of the present invention, and FIG. 3 is a plan view of a tape with a hole in the center. 1: prepreg, 2: metal mirror plate, 3: resin (burrs) melting overflowing from the prepreg, 5: tape with continuous holes in the center of the tape, 6:
Hole, a: prepreg laminate.

Claims (1)

[Scope of Claims] 1. In the production of a laminate formed by heating and press-molding a laminate obtained by stacking one or more prepregs obtained by impregnating and drying a laminate base material with a laminate resin. , characterized in that a piece of tape with a continuous hole near the center is brought into contact with or adhered to the periphery of the top and bottom surfaces of the laminate in advance, and then heated and pressure molded. Method of manufacturing laminates. 2. Manufacture of the laminate according to claim 1, wherein a perforated tape is bonded to the side surface of the prepreg laminate and the perforated tape so as to maintain a gap between the prepreg laminate side surface and the perforated tape, and then heat and pressure molding is performed. Method. 3. The prepreg according to claim 1 or 2, wherein the prepreg constituting the laminate has a part or all of its peripheral portion having lower heating fluidity than the central portion. Method of manufacturing laminates. 4. The tape according to claim 1, 2, or 3, wherein a curing accelerator for the laminate resin is coated on the surface of the tape in contact with the laminate. Method of manufacturing laminates. 5. Claims 1, 2, 3, or 4, characterized in that the tape has a release agent coated on a surface opposite to the surface in contact with the laminate. Method of manufacturing the described laminate. 6 In the production of a laminate made by heating and press-molding a laminate obtained by stacking one or more prepregs obtained by impregnating and drying a laminate base material with a laminate resin, continuous holes near the center are formed. A piece of tape with blank spaces is brought into contact with or attached to the periphery of the top and bottom surfaces of the laminate in advance, and then the portion of the tape that is in contact with or attached to the laminate is 1. A method for manufacturing a laminate, comprising heating and press-forming the laminate in a state where at least a portion thereof is overlapped with a metal mirror plate.