JPS6014688B2 - Manufacturing method of prepreg for laminates - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing a prepreg used in producing a thermosetting resin laminate (hereinafter referred to as a laminate).

In particular, the present invention relates to a method for producing a prepreg using a base material of glass cloth or glass nonwoven fabric (hereinafter referred to as glass cloth).
Here, thermosetting resins include phenol resins, melamine resins, epoxy resins, unsaturated polyester resins, and the like. The present invention is particularly directed to cases in which a solvent that is insoluble or soluble in water, such as methyl ethyl ketone or toluene, is used when preparing a varnish. Traditionally, for example, epoxy resins have been used as varnishes diluted with methyl ethyl ketone.

By dipping a glass cloth into this varnish,
It was impregnated with resin varnish and then dried to form Bripreg. In this case, if moisture (moisture in the air) adheres to the glass cloth, it is difficult for the glass cloth to be impregnated with varnish that is not compatible with moisture, so air bubbles tend to remain in the prepreg, and the separately applied resin There were drawbacks such as the tendency to cause unevenness, making it difficult to obtain a good prepreg. The present invention was made based on the above circumstances. The present invention is characterized in that the glass cloth is heat-treated before it is impregnated with the resin varnish. The purpose of heating is to remove moisture adhering to the glass cloth, and the temperature for this purpose is preferably 100 to 160°C. As a result, it is recognized that the amount of adhering water is 0.2% by weight or less, and in such a case, the best results can be obtained. Since impregnation of glass cloth with resin varnish is usually carried out continuously, it is desirable that heating is also carried out continuously. Therefore, a prepreg manufacturing apparatus is used in which a heating zone is provided in front of a so-called dip pan for soaking the resin varnish. As described above, when a preheated glass cloth is used, impregnating properties are improved and a prepreg with a good appearance can be obtained, and a laminate using this prepreg does not contain voids and has good measling properties.

Measling property means that due to a sudden temperature difference (for example, when immersed in a soldering bath), the sagging points of the glass fiber warp and horizontal threads separate from the thermosetting resin, resulting in white spots on the appearance. refers to a phenomenon. The reason why the measling property is improved is that by removing the moisture from the glass cloth, the surface treatment agent of the glass cloth and the varnish having twilling properties become better compatible.
This is thought to be because the resin penetrates into the glass filaments that are 0 to 80 mm thick, and as a result, there are no voids in the resulting laminate.

Example 1 m Glass cloth: WE-1 Hinaichihi 2 (manufactured by Nittobo Co., Ltd.)
was used.

'2- The following formulation was used as the epoxy resin varnish.

'3' Dry the above glass cloth at 100℃ using a hot air dryer.
The mixture was heated for 1 minute to remove moisture.

'41 The glass cloth was immersed in the above varnish for 1 time and then pulled up to make a prepreg with a resin adhesion of 4% by weight.
A B-staged prepreg was obtained by drying for 1 piece at 150 pm.

Example 2 The experiment was carried out using the same equipment as in Example 1.

However, the following conditions were different. {1'Glass cloth 14 pieces0
The water was removed by passing the sample between two rolls heated at a speed of 1.0/min.

■Next, soak a glass cloth in the above varnish, adjust the amount of resin adhesion to 4% by weight using a doctor knife, and
This was dried for 0.10 minutes to obtain a B-stage Bripreg.

Example 3 '1' Glass cloth is the same as in Example 1.

'21 The epoxy resin varnish was the same as Example 1 except that the epoxy resin was replaced with FA-1011 (manufactured by Dainippon Ink and Chemicals).

[3' The glass cloth was dried with hot air at 160°C for 1 minute.

A wax preg with a candlestick content of 4% by weight was obtained. Note that the drying conditions were 16 minutes and 0.18 minutes. Comparative example [1'
The glass cloth and epoxy resin varnish were the same as in Example 1.

[Example 1] A glass cloth that had been left at 20°C and 65% R for 10 days (standard condition) was soaked in varnish for 1 hour.
Prepreg was obtained in the same way.

The prepregs obtained in Examples 1 to 3 and Comparative Examples were
Stack them together, put 35mm thick copper foil on both sides, and
7 pi 0, 40 k9/ground, 5 minutes molding condition, 1.6
A laminate of armpit thickness was obtained.

When we investigated the performance of the above implementation, the results were as shown in the following table.

Measling property is a phenomenon in which the intersection points of the vertical and horizontal glass fibers separate from the thermosetting resin due to a sudden temperature difference (for example, when immersed in a solder bath), resulting in white spots on the appearance. means.

The impregnability test was carried out by measuring the time it took for a glass cloth soaked in the varnish to become transparent.

Claims (1)

[Claims] 1. In the manufacturing method of prepreg for laminates, which uses glass cloth or glass nonwoven fabric as a base material and thermosetting resin varnish using a solvent that is poorly soluble or insoluble in water, glass cloth or (and) glass is used in advance. A method for producing prepreg for laminates, which is characterized by heat-treating a nonwoven fabric.