JPH0226580B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a copper-clad laminate for printed wiring boards, and its purpose is to provide an epoxy resin copper-clad laminate that has excellent heat resistance, moisture resistance, and excellent adhesion between copper foil and resin. It is something to do. Conventionally, copper-clad laminates for printed wiring boards have mainly been
This type of copper-clad laminate is manufactured using a resin composition containing dicyandiamide as a curing agent and tertiary amine such as benzyldimethylamine as a curing accelerator in an epoxy resin. Although the adhesion with resin is excellent, there are problems with heat resistance such as a low thermal decomposition temperature, and moisture resistance, such as the pressure solder test (after treating the test piece in steam at 121°C, the test piece is exposed to a solder bath). Problems have been that glass grains lift and delamination phenomena occur during the test. On the other hand, copper-clad laminates using novolak type phenol formaldehyde resin (hereinafter abbreviated as phenol novolak) instead of dicyandiamide as a hardening agent improve the heat resistance and moisture resistance mentioned above, but When an agent such as a tertiary amine such as benzyldimethylamine or various imidazoles is used, the adhesion between the copper foil and the resin is poor. That is, the copper foil had a drawback of low peel strength. In view of these points, the present inventors conducted various studies on the curing accelerator among the resin compositions, and found that
We have arrived at the present invention. The present invention provides an epoxy resin composition comprising an epoxy resin having an average of two or more epoxy groups per molecule, a phenol novolac as a curing agent, and a tertiary phosphine as a curing accelerator. Coating or impregnating a base material such as cloth or glass paper, overlapping copper foil on one or both sides of the resulting prepreg, and molding under heat and pressure to achieve heat resistance, moisture resistance, and adhesion between the copper foil and resin. This article relates to an excellent epoxy resin copper-clad laminate. The reason why adhesion with copper foil is improved when tertiary phosphine is used instead of an amine compound as a curing accelerator is currently unknown, but
This is probably due to some kind of interaction occurring between the phosphorus atom and the copper. Note that the use of tertiary phosphine in an epoxy resin and a compound having a phenolic hydroxyl group is disclosed in JP-A-56-130953 and the like. However, JP-A-48-83199 relates to the production of linear epoxy resin, and does not describe how to three-dimensionally cure the epoxy resin to make it insoluble and infusible as in the present invention. Further, JP-A-56-130953 discloses the composition of an epoxy resin, a phenol novolak, and a tertiary phosphine, but it relates to a composition for a molding material, and the composition of the present invention is applied to a copper-clad laminate. There is no description of using the method to improve the adhesion between metal and resin. Next, the present invention will be explained in more detail. The epoxy resin used in the present invention is not particularly limited as long as it has two or more epoxy groups per molecule on average, but examples include diglycidyl ether type epoxy resin of bisphenol A, butadiene diepoxide, 4,4'-di(1,2-epoxyethyl) diphenyl ether, 4,4'-di(epoxyethyl) biphenyl, diglycidyl ether of resorcinol, diglycidyl ether of phloroglycin, triglycidyl p.aminophenol Ether, 1,3,5-tri(1,2-epoxyethyl)benzene, 2,2'4,4'-tetraglycidoxybenzophenone, tetraglycidoxytetraphenylethane, polyglycidyl of phenol novolak Ether, triglycidyl ether of trimethylolpropane, polyglycidyl ether of cresol novolak, triglycidyl ether of glycerin, diglycidyl ether type epoxy resin of halogenated bisphenol A, polyglycidyl ether of halogenated phenol novolak, triglycidyl isocyanate Examples include alicyclic epoxy resins such as nurate, vinylcyclohexene dioxide, 3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexanecarboxylate, and hydantoin epoxy resins. In addition, in the present invention, when a high molecular weight bisphenol A diglycidyl ether type epoxy resin cannot be used due to its high viscosity, bisphenol A or brominated bisphenol A is used as a reactive modifier, and a low molecular weight epoxy resin is used as the epoxy resin. It is also possible to lower the viscosity by using a bisphenol A diglycidyl ether type epoxy resin. Novolac-type phenol formaldehyde resin (phenol novolac) used as a curing agent includes phenol, cresol, xylenol, ethylphenol, butylphenol, p-
Phenols such as phenylphenol, nonylphenol, bisphenol A, and resorcinol, and aldehydes such as formaldehyde and paraformaldehyde for 1.0 mole of phenols,
It was synthesized by a conventional method using 0.4 to 0.95 moles of aldehydes. The blending ratio of epoxy resin and phenol novolak is 1 epoxy equivalent of epoxy resin,
Amounts of phenol novolac from 0.6 to 1.2 hydroxyl equivalents are desirable; anything outside this range will adversely affect the properties of the cured laminate. Preferably, it is in the range of 0.9 to 1.0 hydroxyl equivalent. The curing accelerator used in the present invention is a tertiary phosphine represented by R ₃ P. Here, R is a monovalent alkyl group, a cycloalkyl group, or an aryl group, and all three groups may be the same group, or any one of them may be different. Examples of tertiary phosphin include trimethyl phosphin, triethyl phosphin, tributyl phosphin, trioctyl phosphin, trilauryl phosphin, triphenyl phosphin, tribenzyl phosphin, alkyldiphenylphosphin,
There are dialkylphenylphosphine, etc. From the viewpoint of stability at room temperature and cost, triphenylphosphine is particularly preferred. The amount of tertiary phosphine is epoxy resin
It is preferably in the range of 0.01 to 5.0 parts by weight per 100 parts by weight; if it is less than 0.01 parts by weight, the effect of accelerating curing will not be seen much, and if it exceeds 5.0 parts by weight, it will adversely affect the properties of the laminate produced by curing. affect Furthermore, in the present invention, in addition to the above-mentioned epoxy resin, phenol novolac, and curing accelerator, a flexibility imparting agent, a viscosity-lowering diluent, a flame retardant, a filler, a pigment, etc. may be added as necessary. . Further, as the base material, any conventionally known base material such as glass cloth, glass nonwoven fabric, paper, organic fiber cloth, etc. can be used. The method for creating copper-clad laminates is to create prepreg using the conventional dry coating method using a solvent, cut it to the specified size, layer copper foil on the surface, and heat and press the prepreg while sandwiching it between mirror plates. Although this is a common method, it is also possible to create a film by applying a solvent-free resin composition to a base material, then layering copper foil on the surface and applying heat and pressure. Hereinafter, the present invention will be explained in detail using examples. However, the present invention is not limited to the following examples. Example 1 Brominated bisphenol A type epoxy resin manufactured by Nippon Ciba Geigy, trade name Araldite 8011 (softening point 75°C, epoxy equivalent 490g/eq. Bromine content 21)
%) to 100 parts by weight of phenol novolak manufactured by Hitachi Chemical, trade name HP-607N (softening point: 85°C, hydroxyl equivalent:
106g/eq.) 21.6 parts by weight were added and heated at 130°C until Araldite 8011 and HP607N became liquid, and then mixed and stirred using a stirring motor for 2 minutes. 1.0 parts by weight of triphenylphosphine was added to this mixture and stirred for 1 minute to obtain a uniform solvent-free resin composition. Next, a 520mm square glass cloth (0.2mm
440 g of this solvent-free resin composition was placed on top of a base material made by laminating glass paper (300 g/m ² ) made by Nippon Vilene Co., Ltd. (thickness: 210 g/m ² , plain weave) so that the central part of the base material was about 400 mm square. was supplied by casting. After layering the same glass cloth as above, 35μTAI-treated copper foil manufactured by Furukawa Circuits Oil Co., Ltd. was layered on both sides, and the upper and lower molds were immediately heated to 170°C and the maximum pressure was placed on the mold.
Hot pressure molding was carried out at 50Kgf/cm ² for 20 minutes. The lower part of the mold is
The upper mold is a 510 mm square flat plate with a trapezoidal protrusion on the inner periphery of the 510 mm square plate with a height of 1.1 mm, a base of 8.5 mm, and a tip of 3 mm wide that slopes toward the inside of the mold. be. Table 1 shows the results of the copper foil peeling strength, thermal decomposition temperature, and pressure soldering test of the obtained laminate. Example 2 Bisphenol A type liquid epoxy resin manufactured by Yuka Ciel Co., Ltd., trade name Epicote 828 (epoxy equivalent
190g/eq.), 33.1 parts by weight of HP-607N, and 58.2 parts by weight of tetrabromobisphenol A (hydroxyl equivalent: 272g/eq.) as a reactive flame retardant (the amount of epoxy resin, amount of HP607N, and The ratio of the amount of bromobisphenol A is equivalent ratio: 1.0:0.59:0.41)
were added and stirred at 130°C until these three components became homogeneous. To this mixture, 4.0 parts by weight of triphenylphosphine was added, stirred for 20 seconds,
A uniform solvent-free resin composition was obtained. This was applied to a base material and heated and press-molded in the same manner as in Example 1 except that the molding time was changed to 10 minutes to obtain a copper-clad laminate. Various properties are shown in Table 1. Comparative Example 1 In Example 2, triphenylphosphine
Benzyldimethylamine instead of 4.0 parts by weight
A copper-clad laminate was obtained in the same manner as in Example 2 except that 4.0 parts by weight was used. Table 1 shows various properties of this laminate. Comparative Example 2 This comparative example is a conventional and commonly made product.
This relates to a FR-4 type copper clad laminate. Araldite 8011, 100 parts by weight, 4.0 parts by weight of dicyandiamide, and 0.2 parts by weight of benzyldimethylamine.
parts by weight were dissolved in methyl ethyl ketone and methyl cellosolve to prepare a solvent-containing varnish with a resin content of 60% by weight. A 0.2 mm thick glass cloth was impregnated with this solvent-containing varnish, and then dry coating was performed at a coating temperature of 160° C. and a coating speed of 1.5 m/min to remove the solvent, thereby obtaining a prepreg. This prepreg is 8
A 35 μTAI-treated copper foil was stacked on both sides of the stack, and these were sandwiched between two mirror plates and heated and pressed at 170° C. for 60 minutes to obtain a 1.6 mm thick copper-clad laminate. Various properties are shown in Table 1.

【table】

[Table] As explained above, according to the present invention, it is possible to create an epoxy resin copper-clad laminate that has excellent heat resistance, moisture resistance, and high copper foil peel strength, and its industrial value is great. It is.

Claims (1)

[Scope of Claims] 1. After coating or impregnating a base material with an epoxy resin composition prepared by blending an epoxy resin with a novolac-type phenol formaldehyde resin and a tertiary phosphine, copper foil is applied to one or both sides of the base material. An epoxy resin copper-clad laminate made by stacking layers and applying heat and pressure. 2. The epoxy resin copper-clad laminate according to claim 1, wherein the tertiary phosphin is triphenyl phosphin.