JPH0755502B2 - Method for impregnating varnish on substrate - Google Patents

Description

TECHNICAL FIELD The present invention relates to a method for impregnating a base material for a decorative board and a base material for a laminated board with varnish.

[Background technology]

Conventionally, when a prepreg is manufactured by impregnating a varnish into a base material for a decorative plate or a base material for a laminated plate such as paper, cloth, glass woven cloth, etc., in general, in order to improve the impregnating ability, Increase the number, increase the distance between rolls,
Although the substrate speed was slowed down, a pressure roll was used, and ultrasonic waves were applied, it was not possible to greatly improve the impregnating property by each method. In addition, continuous vacuum impregnation is difficult, and even if it is continuous, air inflow is large and power cost rises, consumption of sheet parts, frequent warpage twist of base material, increase in cost due to enlargement of vacuum impregnation device Difficulty in maintenance was a problem.

[Object of the Invention]

It is an object of the present invention to provide a method for impregnating a varnish on a substrate, which can be easily continuous and has a simplified impregnation apparatus.

[Disclosure of Invention]

In the present invention, the amount of resin obtained by degassing the substrate is 5 to 50% by weight.
After impregnating the resin varnish (hereinafter simply referred to as “%”), the resin varnish having a resin amount of 50 to 80% subjected to vacuum defoaming treatment is impregnated a required number of times, and a squeeze roll is moved to a base material characterized by Due to the varnish impregnation method, when a resin varnish that does not contain air and has a large air-dissolving power passes around the air remaining in the base material, it strongly absorbs the residual air of the base material and releases it to the outside of the base material. Since there is no residual air inside, the resin varnish can be uniformly penetrated into the base material to eliminate the resin-unimpregnated portion in the base material. The present invention will be described in detail below.

The substrate used in the present invention is glass, inorganic fibers such as asbestos and polyester, polyamide, polyvinyl alcohol,
A woven fabric, a non-woven fabric, a mat or paper made of organic synthetic fibers such as acrylic and natural fibers such as cotton, or a base material having a combination thereof is preferably a base material having a thickness of 0.1 to 0.3 mm.

As resin varnish, phenol resin, cresol resin,
Epoxy resin, unsaturated polyester resin, melamine resin, polyimide, polybutadiene, polyamide, polyamideimide, polysulfone, polyphenylene sulfide, polyphenylene oxide, polybutylene terephthalate, polyether ether ketone, fluororesin, etc. alone or modified Water, methyl alcohol, acetone, cyclohexanone, and a solvent such as styrene are added to adjust the viscosity of the mixture, if necessary, using a mixture, but the vapor pressure at 20 to 25 ° C. is preferably 150 mmHg or less as the solvent. It is preferable to use methyl cellosolve, dimethylformamide or the like. The resin amount of the resin varnish for primary impregnation needs to be 5 to 50%. That is, if it exceeds 50%, the impregnation time will take a long time. Two
The resin content of the resin varnish for the subsequent impregnation needs to be 50 to 80%. That is, if it is less than 50%, the required amount of resin cannot be impregnated, and if it exceeds 80%, the impregnation time will take a long time. The vacuum defoaming treatment of the resin varnish is for both the primary impregnation and secondary impregnation.
It is preferable that the impregnation time is 0 Torr or less and the impregnation time is 1 minute or more. As the resin varnish, the same resin varnish for the first impregnation and the second impregnation and thereafter may be different resin varnishes, and the second impregnation may be the second impregnation length. It is impregnated as many times as necessary, such as secondary impregnation. For the drying, winding, cutting and the like of the base material impregnated with the varnish, those used in the usual production of prepreg can be used. Further, the resin-impregnated base material can be continuously laminated and heat-molded without pressure or pressure.

An embodiment of the present invention will be described below with reference to the drawings.

Example An epoxy resin varnish 1 for primary impregnation having a resin amount of 30% using methyl cellosolve as a solvent was placed in a vacuum kettle 2 at a pressure reduction degree of 22 to 25 Torr.
After degassing for 30 minutes under reduced pressure, the resin varnish was sent to a primary impregnation tank 3 and a glass cloth 4 having a thickness of 0.18 mm and a weight of 200 g / m ² was used.
The epoxy resin varnish 5 for secondary impregnation having a resin content of 20% after being impregnated for 20 minutes and a methylcellosolve solvent as a solvent was further degassed under reduced pressure for 20 minutes at a pressure reduction degree of 20 to 25 Torr in another vacuum vessel 6. The secondary impregnation tank 7 containing the resin varnish was impregnated, adjusted with a squeeze roll 8 so that the total amount of resin was 45%, and then dried to obtain a prepreg.

Comparative Example A prepreg was obtained by treating in the same manner as in Example except that the resin varnish for primary impregnation and the resin varnish for secondary impregnation were used without being subjected to degassing under reduced pressure.

〔The invention's effect〕

Regarding the number of residual air bubbles in the prepregs of Examples and Comparative Examples, as is clear from Table 1, the number of bubbles of the present invention was small, and it was confirmed that the method for impregnating varnish on the substrate of the present invention was excellent.

[Brief description of drawings]

The drawings are simplified process diagrams showing an embodiment of the method of the present invention. 1 is a resin varnish for primary impregnation, 2 is a decompression tank, 3 is a primary impregnation tank, 4 is a base material, 5 is a resin varnish for secondary impregnation, 6 is another decompression tank, 7 is a secondary impregnation tank, 8 Is a squeeze roll, and 9 is a vacuum pump.

Claims (1)

[Claims] 1. A resin varnish having a resin amount of 5 to 50% by weight which has been degassed under reduced pressure, and then has a resin amount of 50 to 50% which has been degassed under reduced pressure.
A method for impregnating a varnish into a base material, which comprises impregnating a resin varnish of 80% by weight a required number of times and moving the squeeze roll in a radial direction.