JPH0414875B2 - - Google Patents

Description

[Detailed description of the invention]

[Object of the Invention] (Industrial Application Field) The present invention relates to a copper-clad laminate that is excellent in machining such as press punching and V-cutting. (Conventional technology) Glass paper cloth base copper clad laminates can be used for computers,
Used in industrial electronics fields such as NC control. These are manufactured in small quantities and in a wide variety of products, and an NC drill machine is used to drill the holes in a variety of hole diameters.
A large number of holes are drilled, ranging from several thousand to tens of thousands of holes per ^m2 , and the external shape is punched out using a router or press mold. Boards used for PCs, OA equipment, game machines, etc. that have recently become available in general households do not require high precision hole positioning or high reliability, and can be delivered in a shorter time and more efficiently. Market demands have changed, requiring lower prices and larger quantities. In order to meet these requirements, press punching of some mounting holes and the outer shape of a thin plate or composite using a mold is quite effective, and is suitable for processing processes in the consumer field. However, when punching or V-cutting is performed using a press mold, the mechanical strength of the glass fiber base material is strong, so the mold wears out significantly, the life of the mold is very short, and the punching shear force is high. Due to the large size, there were disadvantages such as a decrease in press capacity, an increase in the burden, an inability to reduce the hole diameter or distance between holes, and significant wear of the V-cut blade. (Problems to be Solved by the Invention) The present invention has been made to eliminate the above-mentioned drawbacks, and has excellent mechanical workability for punching and V-cutting, and has a long lifespan of molds and V-cut blades. The object of the present invention is to provide a copper-clad laminate that is long and allows reduction in the diameter of punched holes and the distance between holes. [Structure of the Invention] (Means and Effects for Solving the Problems) As a result of intensive research aimed at achieving the above object, the present inventors have discovered that the mechanical properties of the glass fibers constituting the glass paper cloth base material have been improved. The present invention was completed based on the discovery that by lowering the strength, mechanical processing is superior, damage to the mold, etc. is reduced, and the hole diameter and distance between holes can be reduced. That is, the present invention uses, in a copper-clad laminate based on a glass paper cloth, a part or all of a glass paper cloth base material in which the fibers of the glass paper cloth base material have fine scratches to reduce mechanical strength. This is a copper-clad laminate that is characterized by: The glass paper cloth base material used in the present invention is a glass paper cloth base material with reduced mechanical strength. More specifically, the glass fiber used for glass cloth, glass paper, and mixed paper has a tensile strength lowered by 10 to 50% than that of ordinary glass fiber.
If the decrease in mechanical strength is less than 10% than normal,
It has no effect on processability and abrasion resistance of molds, etc., and if it exceeds 50%, the mechanical strength becomes weak and the characteristics as a substrate cannot be achieved, which is not preferable. Methods for reducing the mechanical strength of glass fibers include a scratching method, a heat treatment method, and the like, and any method thereof may be used, and the manufacturing method thereof is not particularly limited. The scarring method is used for glass cloth, and in the process before fluffing and brushing, the glass cloth is rolled over a small diameter roll to create fine scratches in the weft fiber bundles, reducing the mechanical strength of the cloth. It's a method. The heat treatment method is
When heat cleaning glass cloth or drying glass paper, the thermal gradient is made steeper, the temperature rises and cools rapidly, and the glass fibers become brittle, causing scratches and reducing mechanical strength. It's a method. Either method can be used, such as reducing the mechanical strength during the production of glass fiber, or reducing the mechanical strength after it is made into cloth or paper.In short, as long as the mechanical strength is reduced as a base material for glass paper cloth. good. The glass paper cloth base material is not particularly limited and may be either glass cloth or glass paper.
Further, the glass paper may be a mixed paper made of glass fibers and cellulose fibers. Mixed paper can contain up to 70% cellulose fiber. If the cellulose content exceeds 70%, heat resistance will deteriorate, which is not preferable. As for the combination of glass paper cloth substrates, ordinary glass cloths may be alternately combined, or all glass cloths used in the present invention may be used. Similarly, glass paper alone may be used, or it may be combined with ordinary glass paper. Furthermore, it is also possible to use glass paper as a core and arrange glass cloth on the front and back sides thereof. The glass paper cloth base material is impregnated and coated with a thermosetting resin.
Examples include phenol resin, epoxy resin, unsaturated polyester resin, and polyimide resin. Copper-clad laminates are made by first impregnating and coating a glass paper cloth base material with a thermosetting resin, drying it to make a prepreg, and then stacking multiple sheets of this prepreg and copper foil to form a heat-pressure laminate. Manufactured by conventional molding methods. Use of this glass paper cloth substrate with reduced mechanical strength reduces mold wear and extends the life of the mold compared to regular glass paper cloth substrates. Since punching becomes easy, there is no decrease in the shearing force of the press, and there is no wear on the cutting blade. Furthermore, since the holes can be easily drilled, the minimum diameter of the punched holes and the distance between the holes can be reduced. (Example) Next, the present invention will be specifically explained by referring to an example. Example 1 Brominated epoxy resin (epoxy equivalent 500g/
eq) 95 parts by weight, 5 parts by weight of novolac epoxy resin (epoxy equivalent: 180 g/eq), 3 parts by weight of dicyandiamide, and 0.1 part by weight of curing accelerator were dissolved in acetone, and the viscosity was adjusted to 1 poise at 25°C to create an epoxy varnish. (Varnish A) was obtained. The mechanical strength was reduced by heat treatment (tensile strength: 43Kg/25mm (vertical), 40kg (horizontal)
A glass cloth of MIL standard 7628 type (Kg/25mm according to JIS-R-3420) was impregnated with epoxy varnish and dried at 165°C to obtain a prepreg (prepreg A) with a resin coverage of 44% by weight. Layer 8 sheets of this prepreg A, layer 20 μm thick electrolytic copper foil on top and bottom, then place 2.5 mm thick stainless steel plates on top and bottom of the copper foil, and finally layer this with 10 sheets of 200 g/m ² kraft paper. Sandwiched in a sandwich and placed the whole thing on a carrier plate. This is applied at a pressure of 40Kg/cm ² and a temperature of 175℃.
After heating and pressurizing for 90 minutes under these conditions, the pressure was released, and after cooling for 90 minutes at a contact pressure of 5 kg/cm ² , a copper-clad laminate with a thickness of 1.6 mm was obtained. Example 2 Varnish B was obtained by adding 40% by weight of filler to Varnish A obtained in Example 1. Varnish B was impregnated and coated on glass paper in the same manner as prepreg A obtained in Example 1, and dried to produce prepreg B with a resin adhesion of 80% by weight.
I got it. Five sheets of this prepreg B are stacked, one sheet of prepreg A is placed on top and bottom of the prepreg B, and an electrolytic copper foil with a thickness of 20 μm is layered, and a stainless steel plate is prepared in the same manner as in Example 1.
A cushion material was sandwiched and then heated and pressed in the same manner to obtain a copper-clad laminate with a thickness of 1.6 mm. Comparative Example 1 Instead of the glass cloth that was heat-treated in Example 1 to reduce its mechanical strength, a glass cloth with normal mechanical strength (tensile strength 68 kg/25
Prepreg C was obtained in the same manner as in Example 1, except that glass cloth of the MIL standard WE-7628 type having a width of 51 kg/25 mm (according to JIS-R-3420) was used, and a copper-clad laminate was obtained in the same manner. I got it. Comparative Example 2 Using the prepreg B obtained in Example 2 and the prepreg C obtained in Comparative Example 1, five sheets of prepreg B were stacked in the same manner as in Example 2, and one sheet of prepreg C was stacked above and below it, Thereafter, in the same manner as in Example 2, a copper-clad laminate having a thickness of 1.6 mm was obtained. The copper-clad laminates obtained in Examples 1 and 2 and Comparative Examples 1 and 2 were tested for mechanical properties, electrical properties, dimensional stability, through-hole reliability, punching finish, and processing jig wear. Therefore, the results are shown in Table 1. In all cases, the excellent effects of the present invention were recognized. The above characteristics were tested as follows.
Mechanical properties (bending strength) were tested according to JIS-C-6481 with n=7. Electrical properties (surface, volume resistance) were tested according to JIS-C-6481. Dimensional stability was expressed as percentage change in dimensional shrinkage by MIL method. It is expressed by subtracting the dimensional shrinkage after etching from the dimensional shrinkage after heat treatment at 170℃ for 30 minutes, and dividing the difference by (-/
×100). Through-hole reliability is 0.9φ hole after cooling cycle at -65℃ for 30 minutes and 125℃ for 30 minutes.
Continuity resistance value of 1000 holes through hole pattern is 10
It is expressed as the number of cycles until the percentage increase. Regarding the punching finish, for FR-4, the extent of cracks occurring at the punched corners of the 250 x 150 mm pattern was shown, and for CEM-3, cracks were observed between 2.5 pitch IC holes. Wear of the machining jig was evaluated by evaluating the degree of wear after n=7 machining.

【table】

[Table] [Effects of the Invention] As is clear from the above explanation and Table 1, the copper-clad laminate of the present invention has improved performance by using a glass paper cloth base material with reduced mechanical strength. It has excellent mechanical workability for punching and V-cutting, has a long life with less wear on the mold and cutting blade, and can reduce the punched hole diameter and distance between holes.
It is very suitable for industrial use.

Claims (1)

[Scope of Claims] 1. In a glass paper cloth base copper-clad laminate, a portion or parts of the glass paper cloth base material whose mechanical strength is reduced by having fine scratches in the fibers of the glass paper cloth base material are used. A copper-clad laminate that is characterized by being fully used. 2. The copper-clad laminate according to claim 1, wherein the glass paper cloth base material of the copper-clad laminate is glass cloth. 3. The copper-clad laminate according to claim 1, wherein the glass paper cloth base material of the copper-clad laminate is glass paper. 4. The copper-clad laminate according to claim 1 or 3, wherein the glass paper cloth base material of the copper-clad laminate is a mixed paper made of glass fiber and cellulose fiber. 5. The copper-clad laminate according to claim 1, wherein the glass paper cloth base material of the copper-clad laminate is a mixed paper with glass cloth arranged on the front and back sides.