JPH0428016B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Application Field] The present invention relates to a method for manufacturing an epoxy laminate for printed wiring boards using a prepreg impregnated with a solvent-free epoxy resin varnish containing a compound having an unsaturated double bond as a reactive diluent. It is related to. [Conventional methods and their problems] Epoxy resin laminates for printed wiring boards are mainly manufactured using prepregs obtained using varnishes containing solvents. However, this method
In the prepreg manufacturing process, it is necessary to remove the solvent contained in the varnish, and the drying process requires a large amount of heat and is difficult to recover, so not only is most of it wasted, but it also degrades the working environment. There was also a risk of fire and explosion. Furthermore, it is impossible to completely remove the solvent in order to maintain the prepreg at the B-stage, and residual solvent may cause defects in soldering heat resistance and other physical properties. As a countermeasure to this problem, there is a method of using a solvent-free varnish. For example, JP-A-57-109829, JP-A-57-
Dicyandiamide-cured epoxy resin system, amine-cured epoxy resin system as disclosed in JP-A No. 44619, JP-A-58-15528, JP-A-57-70127, etc.;
58-107312, JP-A-58-87122, JP-A-58-87123
Novolak type phenol-cured epoxy resin system as disclosed in JP-A-57-57626, JP-A-57
-9742, JP-A-59-49240, polybasic acid anhydride-cured epoxy resin systems; other examples include dibasic acid hydrazide-cured epoxy resin systems, ring-opening polymerization-cured epoxy resin systems, and the like. The requirements for these solvent-free epoxy resin systems are that the varnish is uniform, that the viscosity is low enough to be impregnated into the base material, that the pot life is long, and that it is easy to B-stage the prepreg itself. It is stable and has a high curing speed of the prepreg during lamination molding, and the physical properties of the obtained laminate are good. By the way, solvent-free varnishes such as those based on dicyandiamide-cured epoxy resins and amine-cured epoxy resins have a drawback in that they are too viscous to be used as they are with only the epoxy resin component. For this reason, using reactive diluents with unsaturated double bonds to lower the viscosity has the disadvantage of deteriorating various physical properties such as heat resistance, moisture resistance, and mechanical properties. This method was still insufficient in terms of creating an epoxy resin laminate with physical properties equivalent to or better than those of the laminate. [Means for Solving the Problems] As a result of intensive studies in order to solve the above problems, the present inventors found that, as curing catalysts, latent curing catalysts, tertiary amines or imidazoles, and organic peroxides were used. By using the three components of
We have discovered a method for producing glass epoxy laminates with improved heat resistance, moisture resistance, and solvent resistance (especially resistance to methylene chloride), and have completed the present invention. That is, in the present invention, the epoxy equivalent is 100 to 500.
A latent curing catalyst, a tertiary amine, or A reinforcing base material is impregnated and heated at a temperature of 40 to 100°C with a solvent-free varnish prepared by adding a curing catalyst consisting of imidazoles and organic peroxides as essential components and mixing at 60 to 110°C. A method for manufacturing epoxy resin laminates for printed wiring boards, which is characterized by stacking one or more B-stage prepregs obtained by the above process, and layering metal foil on one or both sides as necessary. be. The configuration of the present invention will be explained below. The epoxy resin (a) having an epoxy equivalent of 100 to 500 in the present invention includes bisphenol epoxy resins such as bisphenol A epoxy resin, bisphenol F epoxy resin, and tetrabromobisphenol A epoxy resin; Phenol novolak type epoxy resins such as easy type epoxy resin, cresol novolak type epoxy resin, nuclear brominated phenol novolak type epoxy resin; ethylene glycol, propylene glycol, polyethylene glycol, polypropylene glycol, neopentyl glycol, glycerin, trimethylol Polyglycidyl ethers of polyhydric alcohols such as ethane, trimethylolpropane, or adducts of ethylene oxide or propylene oxide to bisphenols; such as adipic acid, phthalic acid, hexahydrophthalic acid, or dimer acids. Examples include polyglycidyl esters of polycarboxylic acids, and the epoxy equivalent of these alone or in mixtures is
100-500. Examples of the compound having an unsaturated double bond of the present invention include divinylbenzene, diallyl phthalate, glycidyl methacrylate, allyl glycidyl ether, and triallyl isocyanurate. Particular preference is given to reactive diluents having groups. The amount to be used should be 5 to 20 parts by weight per 100 parts by weight of the epoxy resin. If it is less than 5 parts by weight, the viscosity of the varnish will become high, and if it is used in excess of 20 parts by weight, the adhesion of the copper foil of the laminate will be affected. Chemical resistance etc. tends to decrease, which is not preferable. The latent curing catalyst used as the curing catalyst of the present invention includes dicyandiamide, hardener HT-2844 (manufactured by Ciba Geigy Corporation) which is a dicyandiamide derivative, succinic acid hydrazide, adipic acid hydrazide, isophthalic acid hydrazide, salicylic acid hydrazide, etc. , dicyandiamide and dicyandiamide derivative hardener HT-2844
are preferred, and the latter is particularly preferred since it has good compatibility with epoxy resins. The amount to be used is appropriately selected depending on the type of epoxy resin used, the type of reactive diluent, and the usage ratio, but usually,
2 to 40 parts by weight per 100 parts by weight of epoxy resin,
The amount is preferably from 3 to 10 parts by weight; if it is less than 2 parts by weight, curing will be insufficient, and if it exceeds 40 parts by weight, storage stability will be shortened, which is not preferred. In addition, as tertiary amines, tri-2,
4,6-dimethylaminomethylphenol, 2-
dimethylaminomethylphenol, piperidine,
Benzyldimethylamine, triethanolamine, triethylamine, pyridine, (1,8-diaza-bicyclo(5,4,0)undecene-7,
and salts of these amines with phenol, 2-ethylhexanoic acid, oleic acid, diphenylphosphous acid, and organic phosphoric acid compounds.Imidazoles include 2-methylimidazole, 2-ethylimidazole, 1,2 -dimethylimidazole, 2-isopropylimidazole, 2-undecylimidazole, 2-phenylimidazole, 4-methylimidazole, N-ethylimidazole, 2-phenyl-4-methylimidazole, 1-benzyl-2-methylimidazole, 2
-Ethyl-4-methylimidazole, imidazole and a metal chain such as Cu, Ni or Co, cyanoethylimidazole obtained by the reaction of 2-methylimidazole with acrylonitrile, etc., and products to which trimellitic acid, etc. are added. Can be mentioned. The amount used is epoxy resin 100
0.05 to 5 parts by weight, preferably
The amount is 0.1 to 1 part by weight, and if it is less than 0.05 parts by weight, curing is slow, and if it is more than 5 parts by weight, the curing rate is high and difficult to control, which is not preferred, as it may cause defects. Furthermore, as organic peroxides, benzoyl peroxide, P-menthane hydroperoxide, tert-butyl perbenzoate, di-
Examples include tertiary butyl peroxide. The amount to be used is selected in a suitable range mainly depending on the amount of unsaturated double bonds in the reactive diluent, but it is usually 0.05 to 1.0 parts by weight, preferably 0.1 to 0.5 parts by weight, based on 100 parts by weight of the reactive diluent. If the amount is less than 0.05 part by weight, the polymerization reaction will be insufficient, and if it is used in excess of 1.0 part by weight, gelation will occur, which is not preferable. The components explained above are mixed to form the solvent-free liquid varnish of the present invention. The mixing order of each component is not particularly limited, but usually the epoxy resin components
After heating the polyfunctional reactive diluent (b) having an unsaturated double bond to (a) to a temperature of 100°C or less and uniformly stirring and mixing it into a liquid, add the latent curing catalyst to the curing catalyst. , tertiary amines or imidazoles, and organic peroxide are added and mixed with stirring. When preparing a solvent-free varnish, internal mold release agents,
Well-known and commonly used additives such as pigments may be added, and trifunctional or higher functional epoxy resins and polyfunctional acid anhydride curing agents may be added to the epoxy resin [(a) (b)] may be added in an amount of 10% by weight or less. The prepreg of the present invention is prepared by impregnating and heating a reinforcing base material with the varnish prepared by the above method. The reinforcing base materials include fibrous reinforcing materials of various shapes such as roving, chopped strand mat, continuous mat, cloth, roving cloth, surfing mat and chopped strand, as well as glass fiber and carbon fiber. , fully aromatic polyamide fibers, and blends thereof,
In particular, alkali-free, silane coupling agent-treated glass cloth, which is used in laminates for electrical applications, is preferably used. 30 to 70% by weight of the prepreg obtained by heating the solvent-free varnish of the present invention to 40 to 100 °C, preferably 50 to 80 °C, and impregnating and applying it to a base material,
In particular, impregnated in a range of 40 to 55% by weight,
Usually, this is done at a temperature of 80 to 180℃, preferably 140 to
Heat it at 160℃ to make B-stage prepreg.
In addition, B-
It can also be used as stage prepreg. Using one or more sheets of prepreg obtained by the above manufacturing method, if desired, metal foil (for example, electrolytic copper foil, etc.) is layered and sandwiched between mirror plates under normal lamination molding conditions, temperature 100-200℃, pressure. 5~
The laminate of the present invention is manufactured by lamination molding at 100 kg/cm ² for 0.5 to 5 hours. [Example] Examples and comparative examples will be shown and explained below. Note that "parts" and "%" in Examples and the like are based on weight unless otherwise specified. Example 1 The following components were thoroughly mixed using a homomixer to obtain a varnish with a uniform viscosity of 50 cps (at. 80°C). ●Bisphenol A diglycidyl ether (trade name: Epicote 828, epoxy equivalent 190) 90 parts ●Glycidyl methacrylate 10 parts ●Dicyandiamide 4 parts ●1-Benzyl-2-methylimidazole 0.5 parts ●Di-t-butyl peroxide 0.2 parts This solvent-free varnish was impregnated into a glass woven fabric with a thickness of 190 μm at 80°C to an impregnation rate of 45%.
C. for 7 minutes to prepare a B-stage prepreg. Eight sheets of this prepreg were laminated with μm-thick copper foil on both sides, and laminated and molded at a temperature of 175° C. and a pressure of 40 kg/cm ² for 2 hours to obtain a double-sided copper-clad laminate with a thickness of 1.6 mm. The properties of this laminate are shown in Table 1. Examples 2 to 5 In Example 1, a varnish was prepared using triallyl isocyanurate, divinylbenzene, diallyl phthalate, and allyl glycidyl ether instead of glycidyl methacrylate, and a double-sided copper-clad laminate was created using this. . The properties of this laminate are shown in Table 1. Example 6 In Example 1, hardener HT-2844 (manufactured by Ciba Geigy Corporation) was used instead of dicyandiamide.
A varnish was prepared using 8 parts, and a double-sided copper-clad laminate was made using this. The first characteristic of this laminate is
Shown in the table. Comparative Example 1 The following components were thoroughly mixed using a homomixer to obtain a varnish with a uniform viscosity of 210 cps (at. 80°C). ● Bisphenol A diglycidyl ether (trade name: Epicote 828, epoxy equivalent 190) 100 parts ● Dicyandiamide 5 parts ● 1-benzyl-2-methylimidazole 0.5 parts The same procedure as in Example 1 was carried out except that this solvent-free varnish was used. . The results are shown in Table 1. Comparative Example 2 Methyl ethyl ketone solution (non-volatile content) of bisphenol A type epoxy resin (epoxy equivalent: 500)
60wt%), add 34 parts of acetone to 125 parts, add 4 parts of dicyandiamide, and dimethylbenzylamine.
A prepreg was prepared in the same manner as in Example 1, except that a solution method varnish was prepared by mixing a curing agent solution in which 0.2 parts of methylcellosolve was dissolved in 30 parts of methylcellosolve, and a double-sided copper-clad laminate was obtained. The test results for this laminate are shown in Table 1.

[Operation and effects of the invention]

As is clear from the above detailed description of the invention, examples, and comparative examples, the solvent-free varnish of the present invention and the method for manufacturing a laminate from prepreg using the same have excellent storage stability, etc. of the varnish, and a low viscosity. It is easy to manufacture prepregs because of the low diluent content, and the physical properties of copper-clad laminates and laminates made from the prepregs are significantly superior to those that do not use reactive diluents that have unsaturated double bonds. Therefore, it is possible to provide highly practical laminates that are equivalent to or better than copper-clad laminates and laminates made using conventional solvent-containing varnishes, and can be used extremely suitably for manufacturing printed wiring boards. I understand that there is something.

Claims (1)

[Claims] 1 Epoxy resin (a) with an epoxy equivalent of 100 to 500 and a polyfunctional reaction diluent (b) having an unsaturated double bond
A curing catalyst containing three components as essential components: a latent curing catalyst, tertiary amines or imidazoles, and an organic peroxide is added as a curing catalyst to an epoxy resin composition containing as essential components, and 110
B-stage obtained by impregnating and heating a reinforcing base material with a solvent-free varnish mixed at 40-100°C.
1. A method for manufacturing an epoxy resin laminate for printed wiring boards, which comprises stacking one or more prepregs and, if necessary, layering metal foil on one or both sides of the prepreg for lamination molding.