JPH04296542A - Manufacture of laminated sheet - Google Patents

Abstract

PURPOSE:To improve the accuracy of laminated sheet thickness by heat-pressing laminated prepreg sheets which are obtained by impregnating a solventless heat molten thermosetting resin having at least 40 poise in fiber substrates by a conventional method. CONSTITUTION:Lengthy fiber sheet substrates 1 are coated and impregnated with a thermosetting resin composition using a heat-mixing measuring coater 2. The impregnated sheets, after being passed through a laminating roll 3, are laminated with metal foils 4, and they are passed through an endless steel belt press 5 to obtain a laminated sheet. As practical thermosetting resins, epoxy resin, unsaturated polyester resin, and vinylester resin are used solely or mixedly. These resins being solventless, they are free from an economical disadvantage of evaporating a solvent and also pollution problems. Since the solventless liquid resins have viscosity at least 40 poise at room temperature, their flow at forming is slow enough to reduce fluctuation of the laminated sheet thickness.

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 insulating board and a metal-clad laminate for printed wiring boards.

0002

2. Description of the Related Art Conventionally, electrical laminated insulating boards and metal-clad laminates for printed wiring boards are mainly manufactured by the following method. That is, a fiber base material is impregnated with a resin solution in which a thermosetting resin such as epoxy resin, phenol resin, or polyimide resin is dissolved in a solvent, and this is heated to remove the solvent and proceed with the curing reaction of the resin. It is made into B stage and made into prepreg. This is a method in which a plurality of sheets are stacked one on top of the other and heated and pressurized.

[0003] Also, for example, Special Publication No. 60-58031
, Japanese Patent Publication No. 63-35424, a method is employed in which a fiber base material is impregnated with a solvent-free liquid thermosetting resin, such as an epoxy resin or an unsaturated polyester resin, and then cured.

[0004] However, in the process of B-stage resin to produce prepreg, not only does it require a large amount of energy to remove a large amount of solvent, but also recovery of the solvent is difficult and poses pollution problems.

The solvent-free liquid thermosetting resins that can be used are limited to epoxy resin acid anhydride curing systems, radical polymerization systems such as unsaturated polyester resins and vinyl ester resins, and those having low viscosity at room temperature. This is impregnated into a long fiber base material and continuously laminated and molded using, for example, a double endless belt method, but since it is liquid at room temperature, there is a problem of contamination of rolls, belts, metal foils, etc. Because the resin fluidity is high at the time, the lamination molding pressure must be so low as to be virtually no pressure. This low pressure molding results in voids and is prone to warping and twisting.

[0006]

The problem to be solved lies in the difficulty in applying appropriate lamination pressure when laminating and molding a solvent-free liquid thermosetting resin continuously. An object of the present invention is to provide a method for manufacturing a laminate having uniform thickness and excellent appearance by reducing the fluidity of the thermosetting resin during molding.

[0007]

[Means for Solving the Problems] The present invention provides a fiber base material with:
A laminate in which one or more sheets of prepreg obtained by heat-melting and impregnating a solvent-free liquid thermosetting resin composition having a viscosity of 40 poise or more at room temperature are continuously heated and pressure-molded. This is a manufacturing method.

The solvent-free liquid thermosetting resin composition used in the present invention is a mixture of a solvent-free liquid thermosetting resin, a curing agent, and a curing accelerator. This composition does not produce reaction by-products such as condensed water when thermosetting, and has a viscosity of 40 poise or higher, which makes it difficult to coat and impregnate a substrate at room temperature.

[0009] The resin may be an epoxy resin, an unsaturated polyester resin, a vinyl ester resin, a polybutadiene resin, etc., and these may be used alone or in combination. To explain more specifically about epoxy resin, 2 per molecule
It is sufficient to have at least 2 epoxy groups, but for example,
Bisbisphenol A type dilycidyl ether type epoxy resin, bisphenol F diglycidyl ether, phenol novolak type epoxy resin Polyglycidyl ester of polyhydric alcohol, polybasic acid polyglycidyl ester, alicyclic epoxy resin, hydantoin epoxy resins, halogenated bisphenol A type epoxy resins, halogenated novolac type epoxy resins, etc. These epoxy resins may be used alone or in combination. The epoxy resin has good heat-melting properties, and preferably has a melting point of 40 to 120°C.

The epoxy resin curing agent to be used may be amines, acid anhydrides, amides, dicyandiamides, or polyhydric phenols. Raldehyde resin,
It is preferable to use bisphenol A and tetrabromobisphenol A.

[0011] Epoxy resin curing accelerators include tertiary amines, quaternary ammonium salts, various imidazoles,
Examples include boron fluoride complex salts and aminopyridines.

Further, the viscosity of radical polymerization resins such as unsaturated polyester resins varies greatly depending on the molecular weight of the main component such as unsaturated alkyd and the ratio of the crosslinking vinyl monomer. For example, unsaturated polyester resins that are solid at room temperature as disclosed in JP-A-52-92288 are also included.

[0013] If necessary, a flexibility imparting agent, a low viscosity diluent, a flame retardant inorganic filler, and a pigment may be added to the above resin composition.

The above-mentioned thermosetting resin composition is melted by heating and applied to and impregnated onto a fiber base material. The temperature is set to a level that does not allow the curing reaction to proceed sufficiently, and the types of resin and curing agent to be used are appropriately determined.

The fiber base material to be used is one or a combination of two or more of glass cloth, glass nonwoven fabric, cellulose woven fabric and nonwoven fabric, thermoplastic resin sintered sheet, and the like. In order to apply and impregnate these base materials with a resin composition, there are methods of applying a fixed amount to each base material, applying a fixed amount between base materials, or impregnating by dipping.

Next, a method of forming a laminate using the above materials will be explained. For example, as shown in FIG. 1, a thermosetting resin composition is coated and impregnated onto a long sheet-like fiber base material 1 using a heating, measuring, mixing, and coating device 2, and then a laminating roll 3 is used to coat and impregnate the thermosetting resin composition.
, and then the laminate with metal foil 4 is passed through an endless steel belt pressing device 5 to form it. The molding pressure is
Determined appropriately depending on the resin used, but 50 kg/cm
2 or less.

[0017]

[Operation] Since the resin used is solvent-free, molding can be carried out without any uneconomical or pollution problems since the solvent is volatilized. Since it is a solvent-free liquid resin with a temperature of 40 poise or more at room temperature, the resin flows slowly during molding, making it possible to reduce variations in the thickness of the laminate.

[0018]

[Example] Example 1 Bisphenol A type liquid epoxy resin (Epicote 82
8. Epoxy equivalent 190g/eq, Yuka Shell Co., Ltd.) 55
part, tetrabromobisphenol A type epoxy resin (Y
DB40, epoxy equivalent 400g/eq, Toto Kaseisha)
45 parts were mixed and heated at 110°C. A solid resin was obtained at room temperature.

Separately, phenol novolac resin (H40
0, softening point: 70°C, hydroxyl equivalent: 106 g/eq, Meiwa Kasei Co., Ltd.) 43 parts, and 1.5 parts of benzyldimethylamine as a hardening accelerator were heated at 110°C. A solid curing agent was obtained at room temperature.

[0020] The above-mentioned solid resin and solid curing agent were heated and melted using a measuring mixing and discharging device to coat a base material of glass cloth (WE18K, Nittobo Co., Ltd.) so that the resin content was 45%, and the 8 sheets were stacked. Ta.

[0021] Further, on both sides of this resin-impregnated base material, a thickness of 1
A double-sided copper-clad laminate was obtained by laminating 8μ electrolytic copper foil and heating and pressing it at 170° C. and 15 kg/cm 2 for 5 minutes using a double belt press shown in FIG.

Example 2 A double-sided copper-clad laminate was obtained in the same manner as in Example 1, except that the pressure was 40 kg/cm 2 and the time was 2 minutes.

Example 3 A solid resin was obtained by dispersing 60 parts of aluminum hydroxide (Hygilite H42M, Showa Denko KK) in the solid resin described in Example 1.

Glass cloth (WE18K, Nittobosha) 2
Sheet and glass mat EPM4450 (Japan Vilene Co., Ltd.)
The same as in Example 1 except that the three sheets had a CEM3 configuration, and the solid resin and the solid curing agent described in Example 1 were heated and melted with a measuring mixing and dispensing device and applied to the base material so that the resin content was 45%. A double-sided copper-clad laminate was obtained.

Comparative Example Unsaturated polyester resin (PS6835, Hitachi Chemical Co., Ltd.)
100 parts of Perhexa 3M (Nippon Oil Company, viscosity 10P at 25°C), and 60 parts of aluminum hydroxide (Hygilite H42M, Showa Denko Co., Ltd.) were mixed. The viscosity of this resin composition at room temperature was 500P, making it difficult to apply it to a substrate.

[0026]

[Table 1]

[0027]

Effects of the Invention It is possible to apply and impregnate a base material by heating and melting a resin composition that is solid at room temperature, and by molding the resin composition under heat and pressure, a laminate with good thickness accuracy can be obtained.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram of a manufacturing apparatus of the present invention.

[Explanation of symbols]

1 Fiber base material 2 Heating, measuring, mixing and coating device 3 Laminating roll 4 Copper foil 5 Endless steel belt heating and pressing device 6 Endless steel belt

Claims (1)

[Claims] Claim 1: A fiber base material is impregnated by heating and melting a solvent-free liquid thermosetting resin composition having a viscosity of 40 poise or more at room temperature, and one or more sheet prepregs obtained are stacked one on top of the other. A method for manufacturing a laminate, characterized by continuous heating and pressure forming.