JPH03110153A - Production of laminated sheet - Google Patents

Abstract

PURPOSE:To make it possible to produce a laminated sheet with excellent high frequency characteristics in a continuous technique by laminating prepregs made of a fluororesin fabric as a base material in layers while they are continuously transferred, feeding continuously them in a double belt and performing laminate molding thereof. CONSTITUTION:A prepreg 1 is prepd. in continuous lengths by using a fabric of a fluororesin as a base material. The prepregs 1 are continuously fed through guide rolls 6 and are continuously put in layers by means of laminating rolls 7. While a laminate 5 wherein the prepreg 1 and if necessary, a metal foil 10 are put in layers is continuously transferred, this laminate 5 is preheated and continuously introduced in a double belt 2. The laminate 5 is heat-pressed by means of press-heating apparatus 11 between upper and lower endless belts 3 and 4 through the double belt 2 to laminate and adhere the prepregs 1 and the metal foil 10 to obtain a laminated sheet A.

Description

[Detailed description of the invention] [Industrial application field]

The present invention relates to a method for manufacturing a laminate used as a Print F wiring board by a continuous method.

[Conventional technology]

Laminated boards are usually prepared by preparing prepreg by using paper or glass cloth as a base material and impregnating it with a thermosetting resin and drying it, and then cutting this prepreg into a predetermined size, and then cutting the prepreg into a plurality of pieces cut into the specified size. Layering sheets of prepreg and metal foil such as copper foil as necessary, setting these in a press machine with 10 to 14 ffi overlapped via plates, and performing multi-stage lamination molding by heating and pressing for a predetermined period of time using upper and lower heating plates. Manufactured by. However, when manufacturing laminates by multi-stage lamination molding like this,
Since it is a patch work, the work efficiency is low and there are many problems in productivity. For this purpose, the present applicant has proposed a method of manufacturing a laminate using a continuous method, such as in Japanese Patent Laid-Open No. 189439/1983. In other words, multiple sheets of long prepreg are piled up and continuously fed, and if necessary, a long metal foil is piled up, and this is continuously passed through a double belt and heated and pressurized by the double belt. ,
This allows the laminated plates to be formed continuously. According to this method, since the laminate can be manufactured in a continuous molding operation, the production efficiency is dramatically improved compared to multi-stage lamination molding in a batch operation.

[Problem to be solved by the invention]

On the other hand, the frequencies used in fields such as the electronics industry, communications, and computers are being shifted to high-frequency regions, and printed wiring board laminates used in such high-frequency regions are designed to shorten signal propagation delays. Moreover, a smaller dielectric constant is required. For this reason, in order to obtain such a laminate with excellent high frequency characteristics, a resin constituting the laminate, that is, a prepreg resin, which has excellent frequency characteristics, such as a patent application published in 1988-5004, has been developed.
Aromatic polyisocyanates such as No. 34 have been used, but resins with excellent high frequency properties are generally used at high temperatures (250 to 300°C in some cases) for long periods of time (
In some cases, it may be necessary to perform molding for 1 to 2 hours. However, when the prepreg is continuously passed through a double belt and molded under heat and pressure, it is impossible to sustain the molding for a long time at high temperatures. It is not possible to manufacture laminates using the above-mentioned continuous method using double belts, and the current situation is that it is difficult to manufacture laminates with excellent high frequency characteristics using the continuous method. . The present invention has been made in view of the above points, and it is an object of the present invention to provide a method for manufacturing a laminate that can manufacture a laminate with excellent high frequency characteristics by a continuous method.

[Means to solve the problem]

The method for manufacturing a laminate according to the present invention involves continuously feeding a long prepreg 1 prepared using fluororesin cloth as a base material, and stacking a required number of prepregs 1, 1...
This is characterized in that it is continuously fed into a double belt 2 and laminated. The present invention will be explained in detail below. Prepreg 1 is prepared as a long piece by impregnating a base material with a resin varnish and drying it. In the present invention, a fluororesin (polytetrafluoroethylene) cloth is used as the base material. It is. The fluororesin cloth is made as a woven or nonwoven fabric of fluororesin fibers, and for example, one commercially available from Daikin Industries, Ltd. as Volibun cloth can be used. Further, in the present invention, any resin can be used to impregnate the fluororesin cloth, but thermosetting resins such as epoxy resins are particularly preferred. Then, as shown in FIG. 1, this prepreg 1 is unwound from a roll, a predetermined number of sheets are continuously fed through an idle roll 6, and each prepreg 1 is continuously overlapped by a stacking roll 7. . On the other hand, a metal foil 10 such as a copper foil is also formed into a long length and wound into a roll, which is unwound and superimposed on the outer surface of the outermost layer of the above-mentioned superimposed prepregs 1. When manufacturing a double-sided metal foil-clad laminate, two metal foils 10 are used to overlap the outer layer of the superimposed prepreg 1, and when manufacturing a single-sided metal foil-clad laminate, one The metal foil 10 is layered only on the outermost layer of the metal foil 10, and a film such as a 7-fluorine resin film that can withstand temperatures of 150° C. or more and has excellent high frequency characteristics is layered on the other outermost layer. Here, any metal foil 10 can be used, such as one coated with an adhesive or a combination of an aluminum carrier and an ultra-thin copper foil. While continuously feeding the laminate 5 in which a plurality of prepregs 1 and metals 1i10 are piled up as necessary, the laminate 5 is preheated to melt the resin contained in the prepreg 1, and then The laminate 5 is successively introduced into a double belt 2 constituted by an upper and lower endless belt 3.4 which is continuously driven by a drum 9. Preheating is preferably carried out by passing the laminate 5 between the upper and lower high-frequency application electrodes 8.8 and dielectrically heating it under no pressure or under contact pressure. When dielectrically heated, the heating temperature is higher inside the prepreg 1 rather than on the surface, and as in the case of external heating using electric heating, the surface is heated to a high temperature and the curing reaction of the resin on the surface of the prepreg 1 is slowed down. This prevents the process from progressing quickly, and it is possible to reduce the occurrence of voids being included in the laminate due to the air bubbles not being completely removed from the prepreg 1 even when pressurized by the double belt 2. Then, when passing the laminate 5 through the double belt 2 and pressurizing the laminate 5 between the upper and lower endless belts 3 and 4, each endless belt 3 and 4 is equipped with a pressure heating device such as a heating plate i, ti. is arranged so that the laminate 5 can be heated and pressurized by this pressure/heating device 11, which cures the resin of the prepreg 1 and laminates and bonds a plurality of prepregs 1 and metal foils 10 together. It is. Pressure is 20kg/c
It is carried out at a low pressure of about a+2 to 30 kg/cm2 or less, and in some cases it is carried out at a contact pressure. The laminated body thus laminated is continuously drawn out as the double belt 2 is driven, and is led to the idle roller 12 and cut by the cutter 13, thereby cutting the metal foil into a fixed size. It is possible to obtain a laminate A with a high tension. When performing laminated molding using the continuous method as described above,
The 7-component resin cloth that is the base material of prepreg 1 has high high-frequency properties because the fluororesin that is its material has a low dielectric constant and excellent high-frequency properties. It is not necessary to use a resin with excellent high-frequency properties as the resin, and the laminate A with high high-frequency properties can be manufactured by using a resin commonly used for laminates, such as epoxy resin. Therefore, there is no need for long-term molding at high temperatures, which is required when using resin with high high-frequency characteristics, and laminate A with high high-frequency characteristics can be manufactured using the conventional continuous method. It is possible to do so.

【Example】

The present invention will be explained in detail below using examples. 520 parts by weight of a brominated epoxy resin with an epoxy equivalent of 520, 9 parts by weight of nocyanamide, and 2-ethyl-4-
0.5 parts by weight of methyl imiguzole was added and dissolved in a solvent to obtain an epoxy resin varnish. The del time of this finis at 160°C was 10 minutes. Then, using a 0°1 LIffl thick polyvinyl cloth (polytetrafluoroethylene resin woven fabric manufactured by Daikin Industries, Ltd.) as a base material, impregnating it with the above epoxy resin varnish and drying it, the resin content was 50% by weight and the temperature was 160°C. A prepreg with a del time of 1 sob was obtained. Next, using this prepreg, a laminate was manufactured using the continuous construction method shown in FIG. That is, prepreg 8
At the same time, copper foils with a thickness of 0°035 mm are placed on top and bottom of the sheets, and a high-frequency dielectric heating device with an oscillation frequency of 13.56 MHz is used to heat the temperature at the center of the laminate f120-125.
℃, the prepreg resin is melted and introduced into a double belt rotating at a speed of 0.1 m/min, and the double belt is heated for 20 minutes at a pressure of 25 kg/0 m2 and a temperature of 170 ℃. Laminate molding was carried out by passing through the laminate, and the laminate was further cut into a predetermined size to obtain a laminate plate with copper cladding on both sides. 205g/m of the epoxy resin varnish used in the above example
By impregnating the glass cloth in Step 2 and drying it, the resin content was 45% by weight and the gel time at 160°C was 180°C.
prepreg was obtained. This prepreg is 500 x 5
00em+* were cut to a fixed size, 8 sheets were stacked on top of each other, and a 0.035+a ring of copper foil with a thickness of 0.035+a was layered on top and bottom, and this was sandwiched between stainless steel plates with a thickness of 1.51, and a multi-stage hydraulic press was used. Insert between heating discs to 170℃
By heating and pressing for 25 minutes to perform multi-stage lamination molding, a laminate plate with copper cladding on both sides was obtained. Regarding the laminates obtained in the above examples and comparative examples, JIS
The dielectric constant was measured based on C6481. In addition, it was measured how many laminates could be manufactured in the example within the time required to manufacture 100 laminates in the comparative example. These results are shown in the table below. As seen in the results in the table, it is confirmed that the examples using fluororesin cloth as the prepreg base material have a low dielectric constant and excellent high frequency characteristics. It is also confirmed that the continuous production method has high production efficiency.

【Effect of the invention】

As described above, in the present invention, a long prepreg prepared using fluororesin cloth as a base material is continuously fed, a required number of prepregs are stacked, and the sheets are continuously fed to a double belt to be laminated. I decided to mold it, so
Fluororesin cloth, which is the base material for prepreg, has a low dielectric constant and excellent high-frequency properties, and it is necessary to use a resin with excellent high-frequency properties as the impregnating resin (such as epoxy resin, which is commonly used for laminated boards). It is possible to manufacture laminates with high high frequency characteristics even if using
It is possible to manufacture a laminate with high high frequency characteristics using the conventional continuous method without the need for long-term molding at high temperatures.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram of the apparatus used in the present invention, where 1 is a prepreg, 2 is a double belt, and A is a laminate.

Claims (1)

[Claims] (1) Lamination characterized by continuously feeding a long prepreg prepared using fluororesin cloth as a base material, overlapping a required number of prepregs, and then continuously feeding this to a double belt to form a laminated layer. Method of manufacturing the board.