JP2001277273A - Method for manufacturing laminated sheet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for manufacturing an inexpensive laminated sheet stable in various capacities by solving the point at issue in conventional molding using a hot plate press. SOLUTION: One prepreg or a plurality of prepregs and a metal foil or film are superposed one upon another and inserted in the nip between heated rolls to be laminated and molded to manufacture the laminated sheet. In this manufacturing method, the melt viscosity of the resin of the prepreg at the temperature of the rolls is 1-800 poise.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a laminated board, and more particularly to a method of manufacturing a laminated board suitable for a printed circuit board used in electric equipment, electronic equipment, communication equipment and the like.

[0002]

2. Description of the Related Art As for printed circuit boards, demands for miniaturization and high functionality are increasing, but price competition is intense. In particular, multilayer circuit boards, glass cloth base epoxy resin laminates, or glass used for printed circuit boards are used. The cost reduction of any laminate using nonwoven fabric as the intermediate layer base material and glass woven fabric as the surface layer base material has been a major issue. Conventionally, in the production process of these laminates and multilayer circuit boards, after performing circuit processing on copper foil and prepreg or laminated laminate,
An inner layer plate obtained by subjecting a copper foil surface, which is generally referred to as a blackening process, to an oxidation treatment is cut to a predetermined length, overlapped, placed between mirror plates, and inserted into a set or a plurality of sets and inserted between hot plates. Heating and pressing are performed to form a laminate. But,
Large heat loss due to heat and cooling of jigs and heating medium for laminated molding equipment such as hot plates during heat molding, heat dissipation from products, laminated molding equipment surface and piping system, depletion of fuel as heat source, and emission of carbon dioxide Global warming due to gas, pollution of the environment by sulfur oxides and nitrogen oxides, and the like have become problems, and the necessity of reducing fuels as heat sources has become a problem.

[0003] Further, when a multilayer circuit board used for a printed circuit board, a glass cloth base epoxy resin laminate, or a laminate using a glass nonwoven fabric as an intermediate layer base material and a glass woven fabric as a surface layer base material is formed by lamination. Because many layers of copper foil, prepreg, mirror surface plate, etc. are placed in a hot plate in the hot plate, the heat history applied to each laminate during lamination molding differs depending on the position of each laminate in the hot plate. There is a difference in quality such as moldability, warpage, and dimensional change rate, and it has been difficult to supply products with less variation in quality. Conventionally, in the case of forming a laminate having a small variation in quality, there is a method in which a single laminate is formed in a hot plate, but the production efficiency is low and this is impractical. Then, one or more sheets of prepreg and a metal foil or film were superimposed, and inserted between heated rolls to perform continuous lamination molding, and an attempt was made to solve the above problem. However, a problem that voids were inherent occurred. did. Therefore, as a result of intensive studies, it has been found that voids can be eliminated by adjusting the melt viscosity of the resin when the resin is inserted between rolls and laminated and formed.

[0004]

SUMMARY OF THE INVENTION The present invention solves the problems of molding by a conventional hot platen press, that is, the problem that the energy used in laminating molding is large and the quality variation between products is large, and it is inexpensive and has a low cost. It is an object of the present invention to provide a method for manufacturing a laminate having stable performance.

[0005]

SUMMARY OF THE INVENTION The present invention relates to a method of manufacturing a laminated board in which one or a plurality of prepregs and a metal foil or a film are laminated, and inserted between heated rolls to form a laminate. A resin having a melt viscosity of 1 to 800 poise. That is, the main feature of the present invention is a step of adjusting the resin melt viscosity of the prepreg and performing roll forming, and has a feature of being excellent in impregnation into a sheet-like substrate. The present invention has a feature that by adjusting the melt viscosity at the time of roll forming, molding can be performed without voids even in low-pressure roll forming.

In the present invention, the sheet-like substrate made of a fiber material may be a glass fiber substrate such as a glass woven fabric, a glass non-woven fabric, a glass paper, a woven fabric or a nonwoven fabric made of paper, synthetic fiber, or the like. Woven fabrics, nonwoven fabrics, mats, and the like made of fibers, carbon fibers, mineral fibers, and the like are mentioned, and these base materials may be used alone or in combination. As a resin to be applied to these sheet-like substrates to produce a prepreg, generally, a thermosetting resin is used, and an epoxy resin, a polyimide resin, a phenol resin, a melamine resin, and a modified resin thereof are preferably used. However, other resins such as a thermoplastic resin and a natural resin are also used, and the present invention is not limited thereto. For thermosetting resin,
If necessary, a curing agent and a curing accelerator are blended. Further, a filler, a coloring agent, and a reinforcing material can be blended. When an inorganic filler is added as the filler, characteristics such as tracking resistance, heat resistance, and a decrease in coefficient of thermal expansion can be imparted.
Such inorganic fillers include aluminum hydroxide, magnesium hydroxide, calcium carbonate, talc, wollastonite, alumina, silica, unfired clay, fired clay, barium sulfate and the like.

[0007] The amount of resin of the prepreg varies depending on the fiber material, properties and weight (per unit area) of the sheet-like fiber base material, but is usually about 40 to 60% of the weight of the sheet-like fiber base material. In the present invention, the melt viscosity of the prepreg resin at the roll temperature is 1 to 800 poise, more preferably 50 to 600 poise. If the melt viscosity is lower than 1 poise, peeling may occur between the prepreg and the metal foil or sheet after roll forming, which is not preferable. If it is higher than 800 poise, the wetting of the resin to the metal foil or sheet becomes poor and voids are inherent, which is not preferable. Here, the melt viscosity in the present invention is a result measured by a cone plate viscometer. Specifically, after setting the cone plate viscometer to a predetermined roll temperature, the rotation speed was 750 rpm (5 rpm).
0 Hz). As a method for adjusting the melt viscosity of the resin, the application and drying conditions of the resin at the time of preparing the prepreg and / or the roll temperature can be adjusted at the time of roll forming. Since the reaction proceeds, it is desired to perform molding at a temperature as low as possible. Therefore, it is preferable to control the reaction state of the resin of the prepreg, that is, the melt viscosity, by the application and drying conditions.

The prepreg obtained as described above is usually wound up by a winder or the like, or is directly stacked on one or more sheets, and if necessary, a metal foil or a film such as a copper foil is laminated. Heated to form a laminate. In the case of a roll press, it is possible to use a cut inner layer circuit board and a prepreg, but it is preferable to use a rolled one and form it continuously.
In this case, forming is performed through one or a plurality of pairs of rolls. The material of the roll includes metal, rubber and the like.

[0009]

The present invention will be described below with reference to examples and comparative examples.

(Example 1) The resin composition was an epoxy resin (brominated epoxy resin Ep504 manufactured by Yuka Shell Epoxy Co., Ltd.)
8, epoxy equivalent 675) 100 parts by weight, a curing agent (dicyandiamide) 5 parts by weight, and a curing accelerator (2-ethyl-4-methylimidazole) 1 part by weight.
It was applied to a glass woven fabric of 0 g / m2 to obtain a prepreg. The melt viscosity of the resin of this prepreg is 15 at 140 ° C.
It was 0 poise. A copper foil having a thickness of 18 μm was overlaid on the upper and lower surfaces of the prepreg thus obtained,
By passing through between two heating rolls having a gap of 0.14 mm at 0 ° C. to form a pressure, the mixture is heated at 180 ° C. for 1 hour to form a 0.1 mm.
A 1 mm laminate was made.

Comparative Example 1 The prepreg used in Example 1 was similarly molded at a roll temperature of 110 ° C. (the melt viscosity of the resin at 110 ° C. was 950 poise) to produce a laminate.

Comparative Example 2 The prepreg used in Example 1 was similarly molded at a roll temperature of 180 ° C. (melt viscosity of the resin at 180 ° C .: 0.5 poise) to produce a laminate.

In these examples and comparative examples, moldability was evaluated.

[Table 1]

(Measurement method) Melt viscosity of prepreg resin:
The measurement was performed using a cone plate viscometer. Formability: Evaluated by transmission observation and cross-section observation after etching. Continuous moldability: In the above-described method, the state of continuous molding for 2 hours was observed. In Comparative Example 3, gelling of the resin occurred in 30 minutes.

[0015]

The method of the present invention can reduce energy cost, reduce air pollution due to exhaust gas from heat source equipment, and save resources by reducing fuel consumption accompanying downsizing of equipment. Further, at the time of manufacturing a laminate, the quality between products obtained by realizing continuous molding is improved by adjusting the melt viscosity. Furthermore, since it can be cut to an arbitrary length by continuous molding such as a roll press or the like, a portion such as an ear which has conventionally occurred is reduced, and the yield is improved. And it is excellent in terms of cost reduction of raw materials, equipment and processes, and is suitable as an industrial production method of a laminated board.

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Claims (1)

[Claims] 1. A method for producing a laminated board, comprising laminating one or more prepregs and a metal foil or a film, inserting between heated rolls and laminating and molding, wherein the melt viscosity of the prepreg resin at the roll temperature is 1 to 1. 800
A method for producing a laminate, which is a poise.