JPH0575581B2 - - Google Patents

Description

[Detailed description of the invention]

INDUSTRIAL APPLICATION FIELD The present invention relates to a method for manufacturing a flexible metal foil-clad laminate that has strong adhesion to metal foil. Conventional technology Conventionally, metal foil laminates for printed wiring have been made of hard phenol, epoxy copper laminates, polyester,
The main product was a flexible copper-clad laminate based on polyimide film. However, hard copper-clad laminates cannot be bent and applied to three-dimensional wiring, and there are limits to their use in reducing the size and weight of electronic devices. Flexible copper clad laminates are made of polyester polyimide,
Polyamide-imide films and the like have been used, but because these bases do not contain reinforcing base materials, they are generally too soft and have the disadvantage that various parts such as 1C cannot be mounted on them. In order to solve these drawbacks, it is necessary to make the rigid laminate board bendable by making the resin composition that constitutes the laminate flexible. Generally, in order to make a resin composition flexible, it is possible to (1) reduce the crosslink density and (2) add a flexible resin. However, due to the reduction in crosslinking density, when using reactive diluents such as monofunctional glycidyl ethers, uncured substances remain within the molecules of the cured resin, making it easily attacked by chemicals and solvents, and reducing heat resistance. At the same time, it was not possible to make the laminate sufficiently flexible so that it could be bent. On the other hand, when general flexible resins such as dimer acid-modified epoxy resins are added to make them flexible, their reactivity differs from that of general bisphenol-type bifunctional epoxy resins, so chemicals, solvents, etc. It was not possible to add it in large quantities because the chemical resin would be eluted, resulting in poor chemical resistance, poor heat resistance, and poor adhesive strength. Problems to be Solved by the Invention As described above, it has been extremely difficult to obtain a flexible epoxy resin laminate with excellent chemical resistance, heat resistance, and adhesive strength with metal foil. The present invention eliminates the above-mentioned drawbacks; it is bendable, allows parts to be mounted, has chemical resistance,
The purpose of the present invention is to provide a metal foil-clad laminate having excellent heat resistance and adhesive strength with metal. Means for Solving the Problems In order to achieve the above object, the present invention involves laminating and molding a prepreg obtained by impregnating a base material with an epoxy resin composition together with a metal foil laminated on the surface. Obtain a prepreg by impregnating a base material with a composition containing the following substances (a) to (d) (a) Bisphenol type bifunctional epoxy resin (b) Trifunctional or higher polyfunctional epoxy resin (ha) ) A dicrycidyl ether having a polysulfide skeleton (d) A compound having a difunctional phenolic hydroxyl group, and 5 to 30% by weight of the above (b) in the composition, 5 to 40% by weight of the (c), The molar ratio of glycidyl ether and phenolic hydroxyl group is 0.8 to 1.2. Further, in order to impart flame retardancy, at least a portion of the substance (d) above contains bromine, and the bromine content is 15% by weight or more of the total. Function In the present invention, a bisphenol-type difunctional epoxy resin and a compound having a difunctional phenolic hydroxyl group are used in combination to directly polymerize without crosslinking, thereby making the laminate easy to bend. Then, the crosslinking density is appropriately adjusted by adding a polyfunctional epoxy resin having trifunctionality or more. The amount of the trifunctional or higher functional epoxy resin added is preferably 5 to 30% by weight. Addition amount of trifunctional or higher polyfunctional epoxy resin is 5% by weight
If the amount is less than 30% by weight, the crosslinking density will be too small, resulting in poor chemical resistance and heat resistance. Unable to maintain flexibility. On the other hand, the diglycidyl ether with a polysulfide skeleton used in the present invention has better adhesion to metal foil and better chemical resistance than when ordinary flexible epoxy resin is added. .
The amount added was preferably 4 to 40% by weight. If the added amount of diglycidyl ether having a polysulfide skeleton is less than 5% by weight, the flexibility will be insufficient and bending will not be possible, and if it exceeds 40% by weight, the heat resistance will be significantly reduced. In the present invention, without using a curing agent for epoxy resins (for example, an ammine compound), crosslinking is performed using a polyfunctional epoxy resin having three or more functionalities, and a polysulfide skeleton that is a flexible epoxy resin is used. This goal is achieved through the synergistic effect of the flexibilization of diglycidyl ether. Since no ordinary curing agent is used, it is necessary to set the molar ratio of diglycidyl ether group to phenolic hydroxyl group to 0.8 to 1.2. No matter which mole number increases, heat resistance and chemical resistance deteriorate. If the total bromine content is less than 15% by weight, no heat resistance effect will be obtained, and if it is 15% by weight or more, a remarkable effect will be exhibited. In particular, when the content is 20% by weight or more, self-extinguishing properties of V-0 class according to the UL-94 standard can be obtained. In order to increase heat resistance, a small amount of a combustion resistant additive such as antimony oxide, other fillers, colorants, etc. may be added. Examples Sheet-like substrates used in the present invention include glass fiber cloth, glass fiber non-woven fabric, aramid fiber cloth, aramid fiber non-woven fabric, polyester fiber cloth, polyester fiber non-woven fabric, mixed non-woven fabrics, mixed woven fabrics, etc., and are not particularly limited. do not. As metal foil,
The metal foil may be copper foil, aluminum foil, nickel foil, etc., and the type and thickness are not particularly limited as long as the metal foil has good conductivity. Moreover, metal foil with adhesive can be used if necessary. As adhesives, phenolic,
General-purpose metal foil adhesives such as epoxy, butyral, polyester, polyurethane, and mixtures thereof may be used. The bisphenol type bifunctional epoxy resin used in the present invention is not particularly limited, and may be bisphenol A type, bisphenol F type, or the like. By using in combination with a compound having a difunctional phenolic hydroxyl group,
It polymerizes linearly without crosslinking. The trifunctional or higher functional epoxy resin used in the present invention is not particularly limited, and may be of the phenol novolak type, cresol novolak type, bisphenol A novolak type, or the like. Compounds having a difunctional phenolic hydroxyl group include tetrabromobisphenol A,
There is no particular limitation as long as it is a compound having a difunctional phenolic hydroxyl group such as bisphenol A, but it is better to contain bromine in the form of a compound having a difunctional phenolic hydroxyl group such as tetrabromobisphenol A, which has better heat resistance. In good condition. Examples 1-2, Comparative Examples 1-4 Bisphenol type bifunctional epoxy resin Ep-
828 (epoxy equivalent: 195, made by Yuka Ciel), polyfunctional epoxy resin YDCN-704 (cresol novolatile epoxy resin, epoxy equivalent: 210 made by Toto Kasei), diglycidyl ether ELEP-10 with polysulfide skeleton (epoxy equivalent: 340, Toray Thiokol), Tetrabromobisphenol A
(TBA, bromine content 59%), bisphenol A, curing accelerator 2-ethyl-4-methylimidazole
Mix and dissolve 0.2 parts by weight with methyl ethyl ketone at the mixing ratio shown in Table 1, and apply resin amount of 42 parts to glass fiber cloth.
A prepreg was prepared by impregnating and drying the sample to a weight percentage. Electrolytic copper foils with a thickness of 35 μm were placed on both sides of the prepreg, and heated and pressed at 160° C. and a pressure of 50 kg/cm ² for 30 minutes to obtain a 0.2 mm thick copper-clad laminate. The characteristics of each are also shown in Table 1. Example 3 A polyester nonwoven fabric was impregnated with the varnish prepared in Example 2 to a resin content of 88% by weight, and dried to produce a prepreg. Apply the prepreg to both sides.
A 35μ thick electrolytic copper foil was placed at 160℃ and a pressure of 50Kg/
A copper-clad laminate with a thickness of 0.2 mm was obtained by heating and pressing at cm ² for 30 minutes. Its properties are shown in Table 2. Example 4 An aramid fiber woven fabric (thickness: 0.18 mm) was impregnated with the varnish produced in Example 2 to a resin content of 76% by weight, and dried to produce a prepreg. Electrolytic copper foil with a thickness of 35μ is placed on both sides of the prepreg, and
℃, pressure 50Kg/ ^cm2 for 30 minutes, 0.2mm
A thick copper-clad laminate was obtained. Its properties are shown in Table 2.

【table】

[Table] The test method for the above characteristics is as follows. Copper foil peeling strength: Compliant with JIS-C-6481. Soldering heat resistance: Floated on a solder bath at 280°C and measured the time until blistering occurred. Chemical resistance: The appearance was observed after immersing it in trichlene for 10 minutes at room temperature. Evaluation criteria: ○ No abnormality, △ Slightly rough skin,
× Rough surface bendability: As shown in Fig. 1, the laminate 1 is
It is wrapped around a cylindrical rod 2 with the minimum radius that can be bent without causing a crack (a), and then the bending force is released and the radius R that can maintain the bent state is shown.
(b). Flame resistance: Measured according to the UL-94 standard. Effects of the Invention As described above, the present invention provides bisphenol type 2
A prepreg obtained by impregnating and drying a sheet-like base material with a resin composition containing a functional epoxy resin, a trifunctional or higher polyfunctional epoxy resin, and a compound having a dicrycidyl ether difunctional phenolic hydroxyl group having a polysulfide skeleton. A laminate is produced by stacking the metal foil on top of the metal foil and applying heat and pressure. As a result, it is highly flexible enough to be bent and has excellent adhesive strength, heat resistance, and chemical resistance, making it extremely valuable as a substrate for three-dimensional printed wiring.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram showing a method of testing the bendability of a laminate.

Claims (1)

[Scope of Claims] 1 The following substances (a) to (d) are blended, and (b) is 5 to 30% by weight (c) is 5 to 40% by weight Glycidyl ether group and A method for producing a metal foil-clad laminate, in which a prepreg obtained by impregnating and drying a sheet-like base material with a resin composition having a molar ratio of phenolic hydroxyl groups of 0.8 to 1.2 is laminated together with metal foil placed on the surface. (a) Bisphenol type bifunctional epoxy resin (b) Trifunctional or higher polyfunctional epoxy resin (c) Diglycidyl ether having a polysulfide skeleton (d) Compound having a difunctional phenolic hydroxyl group 2 (d) at least a portion contains bromine,
2. The method for producing a metal foil laminate according to claim 1, wherein the bromine content is 15% by weight or more of the total bromine content.