JPH0776282B2 - Method for manufacturing prepreg for printed wiring board - Google Patents

Description

The present invention relates to an epoxy-glass cloth, which is a material for printed wiring boards,
The present invention relates to a method for manufacturing an epoxy-glass nonwoven fabric prepreg.

[Conventional technology]

With the miniaturization and high performance of electronic devices, the printed wiring boards mounted therein are becoming higher in density by increasing the number of layers, reducing the diameter of through holes, and reducing the hole spacing. For this reason, the demand for the electrical insulation characteristics of printed wiring boards, which has not been a problem so far, has become strict.

Epoxy resins have hitherto been widely used as insulating materials for printed wiring boards. However, with the increase in the density, there has been a problem that a printed wiring board using an epoxy resin is apt to cause insulation failure or conduction breakdown due to metal migration.

Metal migration is a phenomenon in which a metal forming wirings, circuit patterns, electrodes, or the like on or in an insulating material migrates on or in the insulating material due to the action of a potential difference in a high humidity environment.

Also, dicyandiamide, which has been conventionally used as a curing agent for epoxy resins, has poor compatibility with epoxy resins and is highly likely to deposit dicyandiamide when used as a prepreg. For example, the smear that resin adheres to the inner layer circuit copper is likely to occur during drilling, and the long-term heat resistance in air is also poor.

An epoxy resin cured with a polyfunctional phenol resin is a resin system that solves these problems. Compared with the dicyandiamide curing system, the printed wiring board produced by this curing system has less than half the generation of smear, and the long-term heat resistance in air is more than doubled.

However, in all cases, there is a concern that metal migration may occur even in the curing system, and particularly in the dicyandiamide curing system, since the hygroscopicity is high, metal migration easily occurs.

[Problems to be Solved by the Invention]

As a resin excellent in migration prevention, a triazine resin can be mentioned, but it has drawbacks such as a large curing shrinkage at the time of molding, a low adhesive property, and a hardness and brittleness. Further, in the method of adding a triazine compound as an anti-migration agent to an epoxy resin as disclosed in Japanese Patent Publication No. 63-54300, it is difficult to uniformly disperse the triazine compound, resulting in large variations in characteristics.

The present invention has been made in view of the above circumstances, and relates to a method for producing an epoxy-glass cloth and an epoxy-glass non-woven fabric prepreg that gives excellent electrical insulating properties when applied to a material for a printed wiring board.

[Means for Solving the Problems]

That is, the present invention provides (a) a glycidyl ether compound of a polycondensation product of bisphenol A or bisphenol F and formaldehyde.
To 100% by weight of epoxy resin, (b) polycondensation product of bisphenol A and formaldehyde, (c) curing accelerator, (d) phenolic antioxidant or sulfur organic compound antioxidant And (e) a method of producing a prepreg for a printed wiring board, which comprises impregnating a glass cloth or a glass nonwoven cloth with a varnish containing a solvent as an essential component and then drying the prepreg.

Hereinafter, the present invention will be described in detail.

The epoxy resin of (a) contains 1 to 100% by weight of a glycidyl ether compound of a polycondensation product of bisphenol A or bisphenol F and formaldehyde or a mixture thereof as an essential component, but the molecular weight of this epoxy resin is not limited. .

There is no limitation on the type of epoxy resin used as a component other than the above, for example, bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol S type epoxy resin, phenol novolac type epoxy resin, cresol novolac type epoxy resin, alicyclic. There are formula epoxy resins, glycidyl ester type epoxy resins, glycidyl amine type epoxy resins, hydantoin type epoxy resins, isocyanurate type epoxy resins, their halides, hydrogenated compounds, and the like, and some of them can be used together. There is no limitation on the method of mixing these epoxy resins and the temperature.

When flame retardancy is required in the produced prepreg, a halogenated epoxy resin is added to the glycidyl ether compound of the polycondensation product of bisphenol A or bisphenol F and formaldehyde, which are essential components, or a mixture thereof. To do.

Further, the produced prepreg is required to be flame-retardant, and a glycidyl ether compound of a polycondensation product of bisphenol A or bisphenol F and formaldehyde, which is an essential component of the epoxy resin (a), or a mixture thereof is used as an epoxy resin 100 When 80 parts by weight or more of the weight parts are contained, sufficient flame retardancy cannot be obtained only by halogenated epoxy resin, and it is generally called a flame retardant such as tetrabromobisphenol A, decabromodiphenyl ether, antimony trioxide, and tetraphenylphosphine. It is preferable to incorporate the compound described above. In order to maintain the properties as a prepreg for printed wiring boards, the amount of flame retardant other than halogenated epoxy resin should be limited to the necessary minimum amount, and at most 30 parts by weight or less relative to 100 parts by weight of epoxy resin. Is desirable.

Further, when a normal phenol resin is used as a curing agent for an epoxy resin, the heat discoloration of the cured product becomes a problem, but there is no problem in the present invention because (b) a polycondensation product of bisphenol A and formaldehyde is used.

There is no limitation on the molecular weight of the polycondensate of bisphenol A and formaldehyde of (b), and a bisphenol A monomer may be contained. The compounding amount is not limited, but is preferably 1 to 100 parts by weight with respect to 100 parts by weight of the epoxy resin.

Further, a phenol novolac resin may be used in combination within a range that does not impair the effects of the present invention.

As the effect accelerator of (c), an imidazole compound, an organic phosphorus compound, a tertiary amine, a quaternary ammonium salt or the like is used, but the secondary amino group is acrylonitrile,
When an imidazole compound masked with isocyanate, melamine, acrylate or the like is used, it is possible to obtain a storage-stable prepreg which is more than double the conventional storage stability. Examples of the imidazole compound used here include imidazole and 2-
Ethyl imidazole, 2-ethyl-4-methyl imidazole, 2-phenyl imidazole, 2-wendecyl imidazole, 1-benzyl-2-methyl imidazole,
2-heptadecyl imidazole, 4,5-diphenyl imidazole, 2-methyl imidazoline, 2-ethyl-4-
Methyl imidazoline, 2-phenyl imidazoline, 2-
Undecyl imidazoline, 2-heptadecyl imidazoline, 2-isopropyl imidazole, 2,4-dimethyl imidazole, 2-phenyl-4-methyl imidazole,
2-ethylimidazoline, 2-isopropylimidazoline, 2,4-dimethylimidazoline, 2-phenyl-4-
There are methyl imidazoline and the like, and as a maxing agent, there are acrylonitrile, phenylene diisocyanate, toluene diisocyanate, naphthalene diisocyanate, hexamethylene diisocyanate, methylene bisphenyl isocyanate, melamine acrylate and the like.

These curing accelerators may be used in combination of several kinds, preferably in an amount of 0.01 to 5 relative to 100 parts by weight of the epoxy resin.
Parts by weight. If less than 0.01 parts by weight, the effect is small 5
If it is more than part by weight, the storage stability is not good.

As the antioxidant of (d), a phenol-based antioxidant, a sulfur organic compound-based antioxidant, etc. are used.
When the phenolic antioxidant is used, the electrical insulation property can be improved without degrading other properties such as drill workability. As a phenolic antioxidant,
Monophenol compounds such as 1,2,3-trihydroxybenzene, butylated hydroxyanisole, and 2,6-di-t-butyl-4-ethylphenol, and 2,2'-methylene-bis- (4-methyl-6) -T-butylphenol), 4,4 '
Bisphenol-based compounds such as -thiobis- (3-methyl-6-t-butylphenol) and 1,3,5-trimethyl-
2,4,6-Tris (3,5-di-t-butyl-4-hydroxybenzyl) benzene, tetrakis- [methylene-3-
There are polymeric phenolic systems such as (3 ', 5'-di-t-butyl-4'-hydroxyphenyl) propionate] methane. Examples of sulfur organic compound-based antioxidants include dilauryl thiodipropionate and distearyl thiodipropionate. Several kinds of these antioxidants may be used in combination, and the compounding amount is preferably 0.1 to 20 parts by weight with respect to 100 parts by weight of the epoxy resin.

If it is less than 0.1 part by weight, the insulating property is not improved, and if it exceeds 20 part by weight, the insulating property tends to deteriorate.

As the solvent of (e), acetone, methyl ethyl ketone,
Toluene, xylene, methyl isobutyl ketone, ethyl acetate, ethylene glycol monomethyl ether, N, N-
Dimethylformamide, N, N-dimethylacetamide,
There are methanol, ethanol and the like, and these may be used as a mixture of several kinds.

Further, the above-mentioned (a), (b), (c), (d) and (e) are essential components, and if necessary, other compounds can be mixed within a range that does not impair the effects of the present invention.

After impregnating a glass cloth or a glass non-woven fabric with the varnish obtained by blending the above (a), (b), (c), (d) and (e),
Dry in a drying oven at 80 to 200 ° C to obtain a prepreg for a printed wiring board. It is used for producing a printed wiring board or a metal-clad laminate by heating and pressing a prepreg.

〔Example〕

 The present invention will be further described below based on examples.

Example 1 1,000 g of bisphenol A, 220 g of 37% formalin, and 10 g of oxalic acid were placed in a four-necked flask equipped with a cooling tube and a stirrer, refluxed for 2 hours to react, then dehydrated and concentrated to give bisphenol A novolak resin [A]. Obtained. This was used and compounded as follows to obtain a varnish.

Epicron N-865 (bisphenol A novolac type epoxy resin) 100 parts by weight (trade name: manufactured by Dainippon Ink & Chemicals, Inc.) Bisphenol A novolac resin [A] 60 parts by weight 2E4MZ-CN (1-cyanoethyl-2 ethyl-) 4-Methylimidazole) 0.5 part by weight (Brand name: Shikoku Kasei Co., Ltd.) Yoshinox BB (bisphenol antioxidant) (Brand name: Yoshitomi Pharmaceutical Co., Ltd., 4,4'-butylidene bis (3-methyl-) 0.5 parts by weight of methyl ethyl ketone 100 parts by weight This varnish was impregnated in a glass cloth having a thickness of 0.2 mm and dried at 130 ° C. for 5 minutes to obtain a prepreg.

Example 2 A varnish was obtained by using the bisphenol A novolac resin [A] in Example 1 and compounding as follows.

Araldite 8011 (brominated bisphenol A epoxy resin) 80 parts by weight (trade name: manufactured by Ciba-Geigy) Epicron N-865 20 parts by weight Bisphenol A novolac resin [A] 30 parts by weight LX-1006 (isocyanate mask imidazole) (trade name: Daiichi Kogyo Seiyaku Co., Ltd. 0.5 parts by weight Pyrogallol 0.5 parts by weight Acetone 90 parts by weight This varnish was impregnated in a 0.2 mm thick glass cloth and dried at 110 ° C. for 5 minutes to obtain a prepreg.

Example 3 A varnish was obtained by using the bisphenol A novolak resin [A] in Example 1 and compounding as follows.

Epicron N-880 (Bisphenol A novolac type epoxy resin) (Brand name: Dainippon Ink and Chemicals, Inc.) 50 parts by weight ESB-400 (Brominated bisphenol A type epoxy resin) (Brand name: Sumitomo Chemical Co., Ltd.) ) 50 parts by weight Bisphenol A novolac resin [A] 40 parts by weight C ₁₁ Z-AZINE (2,4-diamino-6 {2'undecylimidazole (1 ')} ethyl-S-triazine) 1 part by weight (trade name) : Shikoku Kasei Co., Ltd. DLTP "Yoshitomi" 0.5 parts by weight (Product name: Yoshitomi Pharmaceutical Co., Ltd., dilauryl thiodipropionate) Methyl ethyl ketone 90 parts by weight This varnish is impregnated into a 0.2 mm thick glass cloth 130 Propreg was obtained by drying at 5 ° C for 5 minutes.

Example 4 A varnish was obtained by using the bisphenol A novolak resin [A] in Example 1 and compounding as follows.

Araldite 8011 80 parts by weight Epicron N-880 20 parts by weight Bisphenol A novolac resin [A] 10 parts by weight H-1 (phenol novolac resin) 20 parts by weight (trade name: manufactured by Meiwa Kasei Co., Ltd.) 2PZ-CN (1- (Cyanoethyl-2-phenylimidazole) 0.5 parts by weight (Product name: Shikoku Kasei Co., Ltd.) Yoshinox BB 0.25 parts by weight DLTP "Yoshitomi" 0.25 parts by weight Acetone 90 parts by weight This glass varnish is impregnated with 0.2 mm thick 110 It was dried at ℃ for 5 minutes to obtain a prepreg.

Comparative Example 1 In Example 1, Yoshinox BB was not added.

Comparative Example 2 4 parts by weight of dicyandiamide was mixed in place of the phenol novolac resin in Comparative Example 1, and ethylene glycol monomethyl ether was further added as a solvent.

18 μm on each side of the 8 prepregs thus obtained
A thick copper foil was placed, and a double-sided copper-clad laminate was produced under the press conditions of 170 ° C., 90 minutes, and 50 kg / cm ² . Circuit processing was performed on this MCL and a migration test was performed. Through-hole drilling was performed by using a 0.9 mm diameter drill under the conditions of a rotation speed of 60,000 rpm and a feed speed of 1,800 mm / min. The hole wall spacing was 350 μm, and the insulation resistance of 400 holes (200 holes between through holes) of each sample was measured with time. The test conditions were 100 V applied in an atmosphere of 85 ° C./90% RH, and the number of days until a conductive breakdown occurred between the through holes was measured. The insulation resistance was measured at 100V / 1min.

Solder heat resistance test is conducted at 260 ℃ for MCL with double-sided etching.
After 20 seconds of immersion in the solder, the appearance was visually evaluated, and those without blisters were OK and those with blisters were NG.

The gel time of the prepreg was measured at 160 ° C, and the storage stability of the prepreg was evaluated by measuring the gel time of the prepreg immediately after coating and the prepreg after storage at 20 ° C / 40% RH for 60 days. The results are shown in Table 1.

Examples 1 to 1 containing bisphenol A novolac resin
4 and Comparative Example 1 did not cause continuity breakdown even after 100 days, and showed higher insulating properties than Comparative Example 2 which is a dicyandiamide curing system. Above all, in Examples 1 and 4 in which the bisphenol-based antioxidant was blended, the insulation resistance on the 100th day was higher than in Comparative Example 1, and the long-term insulation characteristics were excellent.

[Effects of the Invention] As is clear from the above description, the prepreg for a printed wiring board of the present invention suppresses the occurrence of metal migration and improves the electrical insulation characteristics as compared with the conventional prepreg.

 ─────────────────────────────────────────────────── ─── Continuation of front page (56) References JP-A-60-260627 (JP, A) JP-A-54-127458 (JP, A) JP-A-61-272243 (JP, A)

Claims (2)

[Claims] 1. An epoxy resin containing (a) a glycidyl ether of a polycondensation product of bisphenol A or bisphenol F and formaldehyde, (b) a polycondensation product of bisphenol A and formaldehyde, (c) a curing accelerator, d) Any one or more of a phenolic antioxidant or a sulfur organic compound antioxidant and (e) a varnish containing a solvent as an essential component are impregnated into a glass cloth or a glass non-woven fabric, and then dried. Manufacturing method of prepreg for printed wiring board. 2. The method for producing a prepreg for a printed wiring board according to claim 1, wherein the phenol-based antioxidant (d) is a bisphenol-based antioxidant.