JPH0121784B2 - - Google Patents

Description

Detailed Description of the Invention The present invention involves impregnating a glass fiber base material and an aluminum hydroxide/glass fiber mixed cellulose fiber base material with a thermosetting resin such as a phenolic resin, an epoxy resin, or an unsaturated polyester resin. Dimensions obtained by drying to form prepregs, arranging these prepregs in a configuration where the surface layer is glass fiber base prepreg and the middle layer is aluminum hydroxide/glass fiber mixed cellulose fiber base prepreg, and laminated under heat and pressure. This invention relates to a thermosetting resin laminate with good stability. Conventional laminates include thermosetting resin laminates based on cellulose fiber paper such as kraft paper and linter paper, and thermosetting resin laminates based on glass fibers such as glass cloth. Furthermore, there are thermosetting resin laminates and the like which are made by combining these base materials. However, when these laminates are made of kraft paper or linter paper as the base material, they have good punching workability but poor dimensional stability and water resistance, and when glass cloth is used as the base material, dimensional stability and water resistance are good. However, the punching workability is poor. Furthermore, even if glass woven fabric is used for the surface layer and kraft paper or linter paper is used as the base material for the intermediate layer, punching is possible, but it is not sufficient, and the dimensional stability and water resistance are also sufficient. I couldn't say that. Recent electronic devices have become smaller and smaller as their uses have expanded.
The demand for weight reduction is increasing, and laminates that can handle higher density are desired, and laminates that have excellent punching workability, water resistance, and dimensional stability are required. In other words, if such a laminate can be obtained, it will be possible to punch through holes, which is extremely significant as it will be possible to achieve high density at a low cost. However, the above-mentioned conventional laminates have not been able to meet this demand. However, the present invention provides a laminate that can meet these requirements, that is, a thermosetting resin laminate that is excellent in punching workability, water resistance, and dimensional stability. To explain the present invention in more detail, as the glass fiber base material, a glass woven fabric or glass nonwoven fabric made of so-called electrical E-glass is used, and as the aluminum hydroxide/glass fiber mixed fiber base material, kraft paper or glass fiber base material is used. Linter paper mixed with aluminum hydroxide and glass fiber is used.
The type of aluminum hydroxide to be mixed is not particularly limited, but it is preferably one with a gibbsite crystal structure that has a high thermal decomposition temperature. This is because the laminate needs to be resistant to heat received during processing, especially during soldering. Next, the average particle size of aluminum hydroxide is preferably 50 microns or less, and more preferably 20 microns or less. If the thickness exceeds 50 microns, water resistance and electrical insulation properties will decrease. The amount of paper mixed is not particularly limited, but it is 30 to 85%.
is the preferred range. If it is less than 30%, the dimensional stability and smoothness of the punched end face will be poor, and if it is more than 85%, the workability during impregnation and drying will be poor. Aluminum hydroxide, which is a mixed material, is preferable because of the transparency of the laminate and the ease of imparting flame retardancy, but dimensional stability can be further increased by mixing a small amount of glass fiber such as E-glass. . Thermosetting resins include phenolic resins, epoxy resins, unsaturated polyester resins, etc.
Coupling agents, pigments, dyes, inorganic fillers, etc. can be mixed into this resin. Prepreg can be obtained by a conventional method, but it is also effective to pre-treat the aluminum hydroxide/glass fiber mixed cellulose fiber base material with water-soluble low-molecular-weight phenol resin, methylol melamine resin, etc. The glass fiber base prepreg obtained in this way and the aluminum hydroxide/glass fiber mixed cellulose fiber base prepreg were arranged to form a surface layer and an intermediate layer, respectively, and heated and pressed to obtain a laminate. It has excellent punching workability, water resistance, and dimensional stability, making it ideal for punching through holes. Further, if necessary, it is also possible to make a copper-clad laminate by laminating copper foil on both sides or one side. On the other hand, even if a laminate was made only from a prepreg made of aluminum hydroxide/glass fiber mixed fiber base material, it would have poor punching workability and heat resistance, and would not be of practical use. By arranging glass fiber base material prepreg as
For the first time, this is a significant laminate that has excellent punching workability, water resistance, and good dimensional stability, and can be used for punching through holes. This will be explained below using examples. Example 1 Glass nonwoven fabric (Nippon Pyrene Co., Ltd. Kiyumuras)
EP-4075) was impregnated and dried with an epoxy resin content of 45% to form a surface layer of prepreg, while aluminum hydroxide/glass fiber mixed paper (mixed paper ratio = aluminum hydroxide/glass fiber/kraft = 80%) was used as the surface layer. /2.5/17.5) with 40% epoxy resin content
A prepreg that has been impregnated and dried so ^that A 1.6 mm double-sided copper-clad laminate was obtained. The properties are shown in Table 1, including punching workability, water resistance,
The laminate had excellent properties such as excellent dimensional stability and no change in conduction resistance of through holes. Comparative Example 1 A double-sided copper-clad laminate with a thickness of 1.6 mm was formed using prepreg that had been impregnated with glass cloth (Nitto Boseki Co., Ltd. WE-18K) to an epoxy resin content of 40% and dried, and its properties were evaluated. It is shown in Table-1. The punching workability was poor, and the punching through holes were not accessible. Comparative Example 2 A double-sided copper-clad laminate with a thickness of 1.6 mm was formed using only the glass nonwoven fabric prepreg used in Example 1, and its properties are shown in Table 1. The dimensional stability was poor, and the conduction resistance of the through-holes varied, making it unsatisfactory for practical use. Comparative Example 3 A double-sided copper-clad laminate with a thickness of 1.6 mm was formed using only the aluminum hydroxide/glass fiber mixed paper prepreg used in Example 1, and its properties are shown in Table 1. The punching workability and heat resistance were poor and it was not suitable for practical use. Comparative Example 4 A prepreg made by impregnating kraft paper with an epoxy resin content of 45% and drying it was made into a sheet with a thickness of 1.6 mm.
Table 1 shows the characteristics of the double-sided copper-clad laminate. The change in conduction resistance of the through holes was large, making it unsuitable for practical use. 【table】

Claims (1)

[Claims] 1. In a thermosetting resin laminate obtained by including a plurality of prepregs impregnated with a thermosetting resin and dried in the base material, both surface layers are made of glass fiber base material prepreg, and the middle layer is made of aluminum hydroxide. A thermosetting resin laminate with good dimensional stability, which is made by arranging glass fiber-mixed cellulose fiber base material prepreg and laminating it under heat and pressure.