JPH0233302B2 - - Google Patents

Description

[Detailed description of the invention]

FIELD OF INDUSTRIAL APPLICATION This invention relates to improvements in composite laminates. BACKGROUND ART Composite laminates used in electronic devices use paper made from linter pulp or wood pulp as a paper base material.
The former consists of almost 100% α-cellulose, while the latter consists of approximately 70-85% α-cellulose.
% by weight, and also contains hemicellulose and the like. Problems to be Solved by the Invention Since α-cellulose has a high degree of polymerization and a high degree of crystallinity, paper made from linter pulp made of 100% α-cellulose is easily impregnated with resin. If used, a composite laminate with good electrical insulation and punching workability can be obtained. However, since cottonseed is used as the raw material for pulp, the supply of raw materials is unstable, and the price is expensive and fluctuates easily. On the other hand, hemicellulose has a low degree of polymerization and is highly hydrophilic, so if paper is made from wood pulp containing α-cellulose and hemicellulose, the electrical insulation and moisture resistance of the resulting composite laminate will decrease, and Since hemicellulose is located in the micellar spaces of α-cellulose, resin impregnation is poor, and in composite laminates with glass cloth placed on the surface, delamination occurs due to the impact during punching, chips occur in the external cross section, and it is difficult to punch. Poor punchability. The present invention provides a composite laminate in which the intermediate layer is a paper base material and the surface layer is a glass cloth base material, which uses wood pulp as the paper base material and has good electrical properties and punching workability. It is something. Means for Solving the Problems The present invention solves the above-mentioned drawbacks, and is a composite laminate in which the intermediate layer is made of a paper base material and the surface layer is made of a glass cloth base material, in which wood pulp is used as the paper base material. 90% by weight α-cellulose
It is characterized by using a cellulose fiber containing the above. Effect By having the above-mentioned characteristics, the present invention has α-
Since the cellulose content is high and the hemicellulose content is low, resin impregnation properties are good, and the resulting composite laminate has improved electrical insulation properties and punching workability. When the content of α-cellulose does not reach 90% by weight, the impregnating properties of the resin are the same as those of conventional paper base materials made from wood pulp, and the resulting composite laminate also has electrical insulation, Good properties cannot be obtained in punching workability. Examples Next, examples of the present invention will be described. Example 1 A 0.25 mm thick kraft paper containing 92% by weight of α-cellulose was impregnated with methylolphenol resin and dried to make the resin amount 10%, and then 100 parts by weight of Ebon 1045 (trade name, epoxy resin manufactured by Yuka Ciel) was added. , dicyandiamide 4 parts by weight, benzyldimethylamine 0.5
It was further impregnated with an epoxy resin varnish consisting of parts by weight and dried to obtain a prepreg with a resin content of 60%. A predetermined number of sheets of this prepreg are laminated, one sheet of glass cloth base material prepreg is placed on top and bottom of the prepreg, and copper foil is further layered on one side, and heated and pressed at a temperature of 160℃ and a pressure of 30Kg/cm ² for 60 minutes. A single-sided copper-clad laminate with a diameter of 1.6 mm was obtained. The glass cloth base material prepreg is made by blending 100 parts by weight of Epicoat 1001 (epoxy resin manufactured by Yuka Ciel), 4 parts by weight of dicyandiamide, and 0.5 parts by weight of benzyldimethylamine, and then adding this to glass cloth to a resin content of 40%. As you can see, it is impregnated and dried. In addition, methylolphenol resin is prepared by adding 2 moles of formaldehyde (37% formalin) and 1 mole of barium hydroxide to 1 mole of phenol.
The reaction product was reacted for 3 hours at °C, the reaction product was neutralized with a 20% sulfuric acid solution, the neutralized salt was removed, and a resin with a solid content of 15% diluted with water was used. Comparative Example 1 Using 0.25 mm thick kraft paper containing 87% by weight of α-cellulose, the thickness was measured under the same conditions as in Example 1.
A 1.6 mm single-sided copper-clad laminate was obtained. Comparative Example 2 A single-sided copper-clad laminate with a thickness of 1.6 mm was obtained under the same conditions as in Example 1 using cotton linter paper with a thickness of 0.25 mm. Conventional Example 1 Using 0.25 mm thick kraft paper containing 82% by weight of α-cellulose, the thickness was measured under the same conditions as in Example 1.
A 1.6 mm single-sided copper-clad laminate was obtained. Table 1 shows the results of characteristic tests conducted on the laminates of Examples, Comparative Examples, and Conventional Examples of the present invention in accordance with JIS-C-6481. In addition, for punching workability, a copper clad laminate with a thickness of 1.6 mm is
The rate of delamination between holes when punched using a test die with a pitch interval of 2.5 mm, a punch diameter of 1.0 mm, and a clearance of 10/100 (both sides) is shown. Punching temperature is 25℃
It is.

【table】

[Table] Effects of the Invention As is clear from Table 1, the composite laminate of the present invention has less hygroscopic deterioration of electrical resistance and less delamination during punching than conventional ones, so it has excellent electrical insulation properties. Excellent in terms of strength and punching workability,
It is excellent. Furthermore, since paper is made from wood pulp, the supply is more stable and the price is lower than that of conventional paper made from linter pulp. , the industrial value of the present invention is enormous.

Claims (1)

[Claims] 1 In a composite laminate in which the intermediate layer is composed of a paper base material and the surface layer is composed of a glass cloth base material, the paper base material constituting the intermediate layer is a fiber made from wood pulp and containing 90% by weight or more of α-cellulose. A composite laminate characterized by using a paper base material made of elementary fibers.