JPS6353033B2 - - Google Patents

Description

[Detailed description of the invention]

INDUSTRIAL APPLICATION FIELD The present invention relates to a method for manufacturing a resin-impregnated base material for a laminate. Conventional technology To manufacture a laminate, first, a long sheet-like base material such as paper, cotton cloth, nonwoven fabric, glass cloth, etc. is transported, and during the transport, a phenol resin, epoxy resin, or unsaturated polyester resin is applied to this base material. A resin-impregnated base material is prepared by impregnating the base material with the following materials and heating it to advance the drying and curing reaction of the resin to the extent that it loses its tackiness at room temperature. Next, one or more of these resin-impregnated substrates cut to predetermined dimensions are stacked one on top of the other, sandwiched between mirror plates, and heated and pressurized to completely cure the resin and obtain a laminate. Also, if necessary, metal foil may be overlapped on one or both sides at the same time. Problems to be Solved by the Invention It is a well-known fact that the performance of laminates is greatly influenced by the way the base material is impregnated with varnish during the impregnation process when manufacturing the resin-impregnated base material. , various studies have been made in the past. Recently, impregnation and coating speeds have been increased to reduce costs, and the viscosity of impregnated varnishes has been increased to reduce solvent use. Conventional methods tend to result in insufficient impregnation, resulting in a decline in the performance of laminates. The present invention was made in order to improve the above-mentioned drawbacks, and an object of the present invention is to provide a method for manufacturing a resin-impregnated base material for a laminate, which allows complete impregnation of resin to the inside of the base material. . Means for Solving the Problems In order to achieve the above-mentioned object, the present invention involves compressing a long sheet-like base material while transporting the base material and prior to impregnating the base material with a resin during the transport. The method is characterized by a step of pressing the base material with a finely textured member or penetrating the base material with the convex portion of the textured member.
The means for pressing or penetrating the material include a method of passing the base material between a pair of rolls having minute irregularities on at least one surface, a method of making microholes in the base material with needle-like protrusions, and the like. Effects According to the above method, the surface area of the base material is significantly increased due to the unevenness, and air bubbles contained in the base material that impede the impregnation rate are also easily removed.
Impregnation unevenness is reduced and the impregnation rate is improved. Examples Base materials that can be applied to the present invention include paper, cotton cloth, glass cloth, glass nonwoven fabric, etc., and examples of resins that can be used include phenol resins, epoxy resins, and unsaturated polyester resins. The resin is preferably diluted to several hundred centipoise or less with a solvent before use. As for the impregnation method, first, as shown in FIG. 1, the base material 2 is passed between a pair of rolls 1 and 1', each of which has fine irregularities on one surface. As for how to apply unevenness to the surface of one roll 1, for example, sandplast finishing or mechanical unevenness can be applied.
The depth of the unevenness is suitably 1 mm or less; if it is too deep, the strength of the base material 2 will be weakened, and depending on the type of the base material, there is a risk of it being cut. The base material 2 is passed between the rolls 1 and 1' to make fine irregularities on its surface, and then brought into contact with the kiss roll 3 to be impregnated with the resin varnish 5, and then passed between the squeeze rolls 4 and 4' to be impregnated with the varnish 5. Adjust the amount to the specified amount. If the above method is adopted, the surface area of the base material 2 will be significantly increased due to the unevenness transferred to the surface thereof, and a particularly large improvement in the impregnation speed can be seen in the step of impregnating the resin varnish 5 from below with the kiss roll 3. In addition, the removal of air bubbles that impede the impregnation rate is improved, and the unevenness of impregnation is greatly reduced. The method of forming fine irregularities on the substrate and the method of impregnation are not limited to those described above. For example, fine holes may be made with a needle to form fine irregularities, or a scraper or a roll coater may be used instead of a squeeze roll. Example 1 Kraft paper with a thickness of 11 mils was pre-treated with surface roughness.
After passing between a 50μ uneven sandplast finish roll and a smooth roll, it was impregnated with tung oil modified phenolic resin varnish from one side using a kiss roll, and then, after being immersed in the varnish, it was passed between squeeze rolls to reduce the amount of resin adhesion to 45μ. It was adjusted to ~48%, dried, and then cut to obtain a resin-impregnated base material for a laminate. After stacking 8 sheets of the base material and then placing copper foil on it, it was sandwiched between mirror plates and inserted into a press at a temperature of 160°C and a pressure of 100°C.
Heated for 60 minutes at Kg/cm ² , pressurized and cooled to 1.6m/m
A thick copper-clad laminate was obtained. Conventional Example 1 Kraft paper with a thickness of 11 mils was directly impregnated with tung oil-modified phenolic resin varnish by kiss rolling and dipping without passing it between uneven finish rolls, and a 1.6 m/m thick paper was coated in the same manner as in Example 1. A copper-clad laminate was obtained. Table 1 shows the performance test results of the copper-clad laminates manufactured according to Example 1 and Conventional Example 1.

[Table] Effects of the Invention As is clear from Table 1, the present invention improves the ability to impregnate the base material with resin, resulting in improvements in the electrical properties, heat resistance, and workability of the laminate. Its industrial value is extremely great as it can speed up the process.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram showing an embodiment of the resin impregnation step in the present invention. 1 and 1' are rolls, 2 is a base material, 3 is a kiss roll,
4 and 4' are squeeze rolls, and 5 is resin varnish.

Claims (1)

[Claims] 1 While transporting a long sheet-like base material, prior to impregnating the base material with resin during the transport, a step of pressing the base material with a fine uneven member or penetrating the base material with the convex part of the uneven member. A method for producing a resin-impregnated base material for a laminate, which comprises impregnating it with a resin and drying it.