JPS6336621B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Application Field] The present invention relates to a method for manufacturing epoxy glass cloth and epoxy glass nonwoven fabric prepreg, which are materials for printed wiring boards. [Prior art] As the density of printed wiring boards increases, the number of layers increases, through holes become smaller in diameter, etc., and prepregs for printed wiring boards with good drillability and metal-clad laminates obtained using prepregs are in demand. has been done. In terms of drillability, the occurrence of smear significantly impairs through-hole reliability by preventing conduction between the inner layer circuit copper and the through-hole plated copper. In order to remove smear, printed wiring board manufacturers perform a smear removal process, but since it uses concentrated sulfuric acid, hydrofluoric acid, etc., there are safety issues and it also roughens the inner walls of the through holes, reducing reliability.
The cause of smear is that the resin softened by the frictional heat during drilling adheres to the cross section of the inner layer circuit copper due to the drilling. Dicyandiamide, which has been conventionally used as a curing agent for epoxy glass cloth prepregs, has poor compatibility with resins and often remains unreacted. Therefore, at temperatures above 250°C, the resin decomposes and softens.In order to prevent such softening of the cured product, a curing agent that is sufficiently compatible with the epoxy resin and has good reactivity is required. Ru. The epoxy resin is also required to have heat resistance and good reactivity. [Object of the Invention] The present invention aims to improve the drill workability, which is a disadvantage of conventional epoxy resin-dicyandiamide systems, and the heat discoloration and storage stability, which are disadvantages of epoxy resin-polyphenol systems. The present invention relates to a method for producing an epoxy-glass cloth prepreg for plates and an epoxy-glass nonwoven prepreg. [Structure of the Invention] The present invention provides (a) an epoxy resin containing 1 to 100% by weight of a glycidyl etherified product of a polycondensate of bisphenol A or bisphenol F and formaldehyde; (b) a polycondensate of bisphenol A and formaldehyde; This is a method for producing a prepreg for a printed wiring board, which comprises impregnating a glass cloth or glass nonwoven fabric with a varnish containing (c) a curing accelerator and (d) a solvent as essential components, and then drying it. The present invention will be explained in detail below. The epoxy resin (a) contains 1 to 100% by weight of a glycidyl etherified polycondensate of bisphenol A or bisphenol F and formaldehyde as an essential component, but there is no restriction on the molecular weight of this epoxy resin. There are no restrictions on the type of epoxy resin used as a component other than the above, and the epoxy resin of the present invention has a faster curing speed and higher crosslinking density than a phenol novolak type epoxy resin or a cresol novolak type epoxy resin alone. Therefore, drill workability is good. This is thought to be because the epoxy resin (a) contains an epoxy resin having the same skeleton as the polycondensate (b), and therefore has good compatibility. Examples of other epoxy resins contained in the epoxy resin of the present invention include bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol S type epoxy resin, phenol novolak type epoxy resin, cresol novolak type epoxy resin, There are alicyclic epoxy resins, glycidyl ester type epoxy resins, glycidylamine type epoxy resins, hydantoin type epoxy resins, isocyanurate type epoxy resins, and their halogenated and hydrogenated products, and several types can be used together. . There are also no restrictions on the method or temperature for mixing these epoxy resins. When flame retardation is required for the manufactured prepreg, a halogenated epoxy resin is required in addition to the essential component glycidyl etherified polycondensate of bisphenol A or bisphenol F and formaldehyde. . In addition, the produced prepreg needs to be made flame retardant, and 100 parts by weight of the glycidyl ether of the polycondensate of bisphenol A or bisphenol F, which is an essential component of the epoxy resin (a), and formaldehyde is added to the epoxy resin. If 80 parts by weight or more of the halogenated epoxy resin is used, sufficient flame retardancy cannot be obtained with just the halogenated epoxy resin, and flame retardants such as tetrabromobisphenol A, decabromodiphenyl ether, antimony trioxide, and tetraphenylphosphine are generally used. It is preferable to blend a compound called . In order to maintain the properties of prepregs for printed wiring boards, the amount of flame retardants other than halogenated epoxy resins should be kept to the minimum necessary, and at most 30 parts by weight of epoxy resin.
It is desirable that the amount is less than parts by weight. In addition, when a normal phenol resin is used as a curing agent for an epoxy resin, there is a problem of heat discoloration of the cured product, but in the present invention, there is no problem because (b) a polycondensate of bisphenol A and formaldehyde is used. . There is no restriction on the molecular weight of the polycondensate of bisphenol A and formaldehyde (b), and bisphenol A monomer may be included. There is no limit to the amount of the compound, but it is preferably 1 to 100 parts by weight per 100 parts by weight of the epoxy resin. Furthermore, a phenol novolac resin may be used in combination within a range that does not impair the effects of the present invention. As the curing accelerator (c), an imidazole compound,
Organic phosphorus compounds, tertiary amines, quaternary ammonium salts, etc. are used, but when using imidazole compounds whose secondary amino groups are masked with acrylonitrile, isocyanate, melamine, acrylate, etc., the Storage stable prepregs can be obtained. The imidazole compounds used here include imidazole, 2-ethylimidazole, 2-ethyl-4-methylimidazole, 2-phenylimidazole, 2-undecylimidazole, 1-benzyl-2-methylimidazole, and 2-heptadecylimidazole. ,
4,5-diphenylimidazoline, 2-methylimidazoline, 2-ethyl-4-methylimidazoline, 2-phenylimidazoline, 2-undecylimidazoline, 2-heptadecylimidazoline,
2-isopropylimidazole, 2,4-dimethylimidazole, 2-phenyl-4-methylimidazole, 2-ethylimidazoline, 2-isopropylimidazoline, 2,4-dimethylimidazoline, 2-phenyl-4-methylimidazoline, etc. Examples of masking agents include acrylonitrile, phenylene diisocyanate, toluene diisocyanate, naphthalene diisocyanate, hexamethylene diisocyanate, methylene bisphenyl isocyanate, and melamine acrylate. Several types of these curing accelerators may be used in combination, and the blending amount is preferably 0.01 to 5 parts by weight per 100 parts by weight of the epoxy resin. If it is less than 0.01 parts by weight, the effect is small, and if it is more than 5 parts by weight, there is no storage stability. Solvents for (d) include acetone, methyl ethyl ketone, toluene, xylene, methyl isobutyl ketone, ethyl acetate, ethylene glycol monomethyl ether, N,N-dimethylformamide, N,
Examples include N-dimethylacetamide, methanol, and ethanol, and several types of these may be used in combination. Moreover, the above (a), (b), (c), and (d) are essential components, and any other compounds can be mixed. After impregnating glass cloth or glass nonwoven fabric with the varnish obtained by blending the above (a), (b), (c), and (d), it is placed in a drying oven.
Dry in the range of 80 to 200°C to obtain prepreg for printed wiring boards. Prepreg is used to manufacture printed wiring boards or metal-clad laminates by heating and pressing. Examples of the present invention will be described below. Example 1 Bisphenol A 1000g, 37% formalin 220
g and 10 g of oxalic acid were placed in a four-necked flask equipped with a condenser and a stirrer and refluxed for 2 hours to react, followed by dehydration and concentration to obtain a bisphenol A novolak resin [A]. Using this, a varnish was obtained by blending as follows. Epicron N-865 (bisphenol novolac type epoxy resin) 100 parts by weight (product name: Dainippon Ink Co., Ltd.) Bisphenol A novolac resin [A]
60 parts by weight 2E4MZ-CN (1-cyanoethyl-2ethyl-
4-Methylimidazole) 0.5 parts by weight (product name: Shikoku Kasei Co., Ltd.) Methyl ethyl ketone 100 parts by weight A 0.1 mm thick glass cloth was impregnated with this varnish.
A prepreg was obtained by drying at 130°C for 5 minutes. Example 2 Using the bisphenol A novolak resin [A] in Example 1, a varnish was obtained by blending as follows. Araldite 8011 (brominated bisphenol A epoxy resin) 80 parts by weight (product name: manufactured by Ciba Geigy) Epicron N-865 20 parts by weight Bisphenol A novolak resin [A]
30 parts by weight LX-1006 (Isocyanate mask imidazole) (Product name: Daiichi Kogyo Seiyaku Co., Ltd.) 0.5 parts by weight Acetone 90 parts by weight A 0.1 mm thick glass cloth was impregnated with this varnish.
A prepreg was obtained by drying at °C for 5 minutes. Example 3 Using the bisphenol A novolak resin [A] in Example 1, a varnish was obtained by blending as follows. Epicron N-880 (bisphenol A novolac type epoxy resin) 50 parts by weight (product name: Dainippon Ink Co., Ltd.) ESB-400 (brominated bisphenol A type epoxy resin) 50 parts by weight (product name: Sumitomo Chemical) Co., Ltd.) Bisphenol A novolak resin [A]
40 parts by weight C ₁₁ Z-AZINE (2,4-diamino-6{2'undecylimidazolyl-(1')}ethyl-S-triazine) 1 part by weight (product name: manufactured by Shikoku Kasei Co., Ltd.) Methyl ethyl ketone 90 Weight part Impregnated 0.1mm thick glass cloth with this varnish 130
A prepreg was obtained by drying at °C for 5 minutes. Example 4 Using the bisphenol A novolak resin [A] in Example 1, a varnish was obtained by blending as follows. Araldite 8011 80 parts by weight Epicron N-880 20 parts by weight Bisphenol A novolak resin [A]
10 parts by weight H-1 (phenol novolac resin) 20 parts by weight (product name: manufactured by Meiwa Kasei Co., Ltd.) 2PZ-CN (1-cyanoethyl-2-phenylimidazole) 0.5 parts by weight (product name: Shikoku Kasei Co., Ltd.) Co., Ltd.) Acetone 90 parts by weight A 0.1 mm thick glass cloth was impregnated with this varnish.
A prepreg was obtained by drying at °C for 5 minutes. Comparative Example 1 Araldite 8011 80 parts by weight EOCN102 (cresol novolak type epoxy resin 20 parts by weight (product name: manufactured by Nippon Kayaku Co., Ltd.) Dicyandiamide 4 parts by weight BDMA (benzyl dimethylamine) 0.5 parts by weight Methyl ethyl ketone 30 parts by weight ethylene glycol monomethyl ether
40 parts by weight Impregnate a 0.1 mm thick glass cloth with this varnish to 160 parts by weight.
A prepreg was obtained by drying at °C for 5 minutes. Comparative Example 2 A prepreg was obtained in the same manner as in Example 1 except that 100 parts by weight of EOCN102S was used instead of 100 parts by weight of Epiclon N-865. Comparative Example 3 In the same manner as in Example 2, except that 0.3 parts by weight of 2E4MZ (2-ethyl-4-methylimidazole trade name: manufactured by Shikoku Kasei Co., Ltd.) was used instead of 0.5 parts by weight of LX-1006. Got prepreg. Comparative Example 4 A prepreg was obtained in the same manner as in Example 2 except that 30 parts by weight of phenol novolak resin H-1 was used instead of 30 parts by weight of bisphenol A novolak resin [A]. Table 1 shows the varnish formulations and drying conditions of Examples and Comparative Examples.

【table】

[Table] Using 15 sheets of prepreg obtained in Examples 1 to 4 and Comparative Examples 1 to 4 above and 6 sheets of 35μ copper foil, a 6-layer printed wiring board was produced by heat molding at 170℃ for 60 minutes, and drilled. I did it. Drilling conditions were rotation speed 60000 rpm, feed rate 3000 mm/min, hole diameter 1.0φmm, number of stacked sheets was 2, and holes were drilled up to 12000 hits. Table 2 shows the results of the drill workability test and other characteristic tests of the 6-layer printed wiring board.

【table】

〔Effect of the invention〕

As described above, it can be seen that the prepreg for printed wiring boards of the present invention has significantly improved drilling workability for multilayer wiring boards and storage stability of the prepreg compared to the prior art.

Claims (1)

[Scope of Claims] 1 (a) An epoxy resin containing a glycidyl ether of a polycondensate of bisphenol A or bisphenol F and formaldehyde (b) A polycondensate of bisphenol A and formaldehyde (c) Curing acceleration 1. A method for producing a prepreg for a printed wiring board, which comprises impregnating a glass cloth or glass nonwoven fabric with a varnish containing an agent and (d) a solvent as essential components, and then drying the impregnated glass cloth or glass nonwoven fabric. 2. Claim 1, wherein the curing accelerator is an imidazole compound with a masked secondary amino group.
A method for manufacturing a prepreg for a printed wiring board as described in .