JPH11188728A - Method and apparatus for impregnating woven fabric base material with varnish - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an apparatus for impregnating a woven fabric base material with varnish capable of reducing voids of a prepreg using the fabric base material. SOLUTION: A varnish impregnating apparatus equipped with a supply roll 1 of a woven fabric base material 10, a guide roll 2 for guiding the woven fabric base material to a varnish impregnation tank 4, an impregnation roll 3, the varnish impregnation tank 4 and a varnish adhesion amt. control unit 5 and allowing the base material 10 to run to the varnish adhesion amt. control unit 5 from the supply roll 1 through the varnish impregnation tank 4, a roll 6 for meandering the base material 10 so as to loosen the flocculation fibers is arranged between the supply roll and the guide roll 2.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method and an apparatus for impregnating a woven fabric substrate with varnish.

[0002]

2. Description of the Related Art Electric laminates, for example, copper clad laminates,
The fiber base material is impregnated with a varnish of a thermosetting resin and dried to form a prepreg. A predetermined number of the prepregs are stacked, copper foil is arranged on both surfaces or one surface thereof, and the prepreg is manufactured by heating and pressing. The fiber base material used here is one in which the fibers are random and loose, such as a paper base material or a nonwoven fabric base, and the other, in which the fibers are aligned and twisted, such as a woven base material. Some are agglomerated, for example. In the prepreg manufacturing process, the process of impregnating the fiber base material with varnish is regarded as the most important process. Conventionally, a continuous belt-like fiber base material 20 is guided from a supply roll 1 to a varnish impregnation tank 4 by a guide roll 2 and an impregnation roll 3, and the fiber base material 2
The fiber substrate 20 is impregnated with the varnish by immersing the varnish in the varnish in the impregnation tank 4, and the varnish adhesion amount control device 5 removes the excess varnish to appropriately control the adhesion amount (FIG. 2).

[0003]

What is essential in the varnish impregnation step is to prevent air bubbles from remaining inside. Originally, the fiber base material has a structure in which air is contained in the space between the fibers. When impregnating the varnish, it is necessary to replace this air with the varnish. The air remaining as bubbles without being replaced by the varnish remains as it is when prepreg is formed, and becomes a so-called void. It is known that a laminate manufactured using a prepreg containing a large amount of voids has poor electric characteristics and heat resistance. Therefore, it is necessary to minimize voids. However, in the case of fibers having a random and loose fiber such as a paper substrate or a nonwoven fabric substrate, the varnish easily penetrates into the voids between the fibers, thereby reducing voids. The varnish hardly penetrated into the voids, and it was difficult to reduce voids. The present invention provides a method and an apparatus for impregnating a woven fabric substrate with varnish, which can reduce voids in a prepreg using the woven fabric substrate.

[0004]

According to the first aspect of the present invention, there is provided a method for impregnating a woven fabric substrate with a varnish, wherein the varnish is impregnated after loosening the fiber aggregation of the woven fabric substrate. is there. Since the permeability of the varnish is improved by relaxing the aggregation of the fibers, the voids can be reduced when the prepreg is formed.

[0005] As a method of loosening the cohesion of the fibers, it is possible to loosen the fibers by hand. However, since the woven fabric base material is supplied in a continuous band, the woven fabric base material is meandered to reduce the cohesion of the fibers. A loosening method is preferred. That is, in the invention of claim 2, in the varnish impregnation method of claim 1, the woven fabric substrate is made to meander so as to loosen fiber aggregation. Here, the meandering that loosens the cohesion of the fibers is a meandering in which the fibers are bent so that the filaments constituting the fibers or the convergence of the filaments is minutely broken.

The invention according to claim 3 provides a supply roll 1 for the woven fabric substrate 10, a guide roll 2 and an impregnation roll 3 for guiding the woven fabric substrate 20 to the impregnation tank 4, a varnish impregnation tank 4, and varnish adhesion. In a varnish impregnating device provided with an amount control device 5 and configured to cause the woven fabric substrate 10 to travel from the supply roll 1 to the varnish adhesion amount control device 5 via the varnish impregnation tank 4, a supply roll 1 and a guide roll 2 are provided. A varnish impregnating apparatus in which a roll 6 for meandering loosening of fiber aggregation is disposed on a woven fabric substrate 10 between them.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION The woven fabric substrate used in the present invention comprises:
There is no particular limitation as long as it is used for laminated boards.
A woven glass substrate having a thickness of 0.05 to 0.3 mm is generally used. Organic fiber woven fabrics can also be used.

The varnish to be used is not particularly limited as long as it is a varnish of a thermosetting resin generally used for a laminated board. For example, a varnish such as a phenol resin, an epoxy resin, and an unsaturated polyester resin may be used. The same applies to the varnish solvent, for example, acetone,
Methanol, methyl ethyl ketone, toluene, ethylene glycol monomethyl ether and the like are used.

In order for the woven fabric substrate 10 to meander so as to loosen fiber aggregation, it is preferable that the woven fabric substrate 10 be meandered with a curvature as small as possible. For this reason, a roll having a diameter of 10 to 30 mm is used as the roll 6 that makes the woven fabric substrate 10 meander so as to loosen fiber aggregation, and the woven fabric substrate 10 meanders while reversing the running direction by 180 degrees. It is preferable to arrange them. At this time, if the diameter of the roll is less than 10 mm, the roll strength is insufficient, and the roll tends to bend during operation. If the diameter of the roll exceeds 30 mm, the curvature becomes too large, and the meandering loosens fiber aggregation. Tends to be difficult. In order to meander the woven fabric substrate 10, the rolls may be arranged in a zigzag shape. The effect of the number of rolls meandering the woven fabric substrate 10 increases as the number of rolls increases. However, the required number depends on the thickness and density of the woven fabric substrate 10 and is appropriately set in a range of about 10 to 30. Selected.

[0010]

Example 1 100 parts by weight of a brominated bisphenol A type epoxy resin (DER-518 (trade name) manufactured by Dainippon Ink and Chemicals, Inc.) and 3 parts by weight of dicyandiamide were mixed with 20 parts by weight of ethylene glycol monomethyl ether. Was dissolved in the mixture to give a varnish. The viscosity at 30 ° C. of the varnish was 100 mPa · s. Twenty rolls having a diameter of 20 mm are arranged between the supply roll 1 and the guide roll 2 so that the running direction of the woven fabric substrate is reversed by 180 degrees and meanders, and the woven fabric substrate is meandered. No. 6 was constructed. The varnish impregnated with the varnish is NE
A glass woven fabric substrate of MA7628 type was impregnated with the amount of varnish adjusted to be 45% by weight in terms of solid content, and dried by heating to prepare a prepreg. The varnish immersion time of the woven fabric substrate was 0.2 minutes, the running speed of the woven fabric substrate was 3 m / min, the dryer set temperature was 170 ° C., and the dryer passage time was 1
0 minutes.

With respect to the obtained prepreg, the area ratio of voids was determined by an image processing apparatus and found to be 20%.

Comparative Example A prepreg was prepared in the same manner as in Example 1 except that the woven fabric substrate was not passed through a meandering roll.

With respect to the obtained prepreg, the void area ratio was determined by an image processing apparatus and found to be 27%.

[0014]

According to the present invention, the voids of the prepreg can be reduced, and a product having excellent electrical properties and heat resistance when formed into a laminate can be obtained.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view of a varnish impregnating apparatus according to an embodiment of the present invention.

FIG. 2 is a schematic sectional view of a conventional varnish impregnating apparatus.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 supply roll 2 guide roll 3 impregnation roll 4 varnish impregnation tank 5 varnish adhesion amount control device 6 roll for meandering woven base material 10 woven base material 20 fiber base material

Claims (3)

[Claims] 1. A method of impregnating a woven fabric base material with varnish, wherein the varnish is impregnated after loosening the aggregation of the fibers of the woven fabric base material. 2. The method for impregnating a woven fabric substrate with varnish according to claim 1, wherein the woven fabric substrate is made to meander so as to loosen fiber aggregation. 3. A supply roll for supplying a woven fabric substrate, a guide roll and an impregnation roll for guiding the woven fabric substrate to an impregnation tank, a varnish impregnation tank, and a varnish adhesion amount control device. In a varnish impregnating apparatus configured to travel to a varnish adhesion amount control device through an impregnation tank, a roll that makes meandering to loosen fiber aggregation on a woven fabric substrate is disposed between a supply roll and a guide roll. Varnish impregnation equipment.