JPH06143271A - Manufacture of glass non-woven cloth base prepreg - Google Patents

Abstract

PURPOSE:To protect a non-woven cloth from cutting in the method of controlling the varnish adhering amount between squeeze rolls rotating reversely to the forwaring direction through the non-woven cloth. CONSTITUTION:A glass non-woven cloth base 2 is impregnated with varnish, and a clearance between squeeze rolls 1 is so adjusted as to be brought into contact with the adhered varnish 5 and not to be brought into contact with the glass non-woven base 2 and the glass non-woven cloth base is passed through between the squeeze rolls 1 rotating reversely to the forwarding direction of the base.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a glass non-woven fabric base material prepreg for a laminate used for producing a printed wiring board.

[0002]

2. Description of the Related Art Nonwoven glass substrates are weaker in tensile strength than glass cloths. Therefore, when trying to adjust the amount of varnish impregnated into the base material, after impregnating the varnish, the squeeze roll is rotated in synchronization with the traveling direction of the glass non-woven fabric substrate (hereinafter referred to as forward rotation) to form the glass non-woven fabric substrate. I tried not to apply tension.

[0003]

When the squeeze roll is rotated in the forward direction, the varnish adheres to the roll from the surface of the substrate after the glass nonwoven fabric substrate has passed between the rolls (the narrowest place).
The amount of varnish deposited on the substrate is not uniform. When a laminated board is formed by using such a prepreg, the thickness, fading,
Defects such as warpage are likely to occur.

As shown in FIG. 2, when the glass non-woven fabric substrate is impregnated with varnish and then the squeeze roll is rotated in the forward direction to control the amount of the attached varnish 5, the surface of the glass non-woven fabric substrate 2 is applied to the surface of the squeeze roll 1. Varnish adheres. The amount of the varnish 3 attached to the surface of the squeeze roll 1 is not constant, so that it is difficult to uniformly control the varnish of the glass nonwoven fabric base material 2. As shown in FIG. 1, when the squeeze roll 1 is rotated in the reverse direction of the glass nonwoven fabric substrate 2 (hereinafter referred to as reverse rotation), the varnish after passing through the squeeze roll 1 does not adhere to the roll, The amount of varnish attached can be made uniform. However, when the squeeze roll 1 is reversed, the tension applied to the glass nonwoven fabric base material 2 increases, and the glass nonwoven fabric base material 2 may be broken.

An object of the present invention is to provide a method in which the nonwoven fabric substrate is not cut even when the squeeze roll is reversed.

[0006]

According to the present invention, the glass non-woven fabric substrate 2 is impregnated with varnish excessively, and then the varnish 5 is attached.
The squeeze roll 1 provided with a doctor knife 4 that adjusts the gap so as not to touch the glass nonwoven fabric base material 2 and rotates in the opposite direction of the glass nonwoven fabric base material 2 to scrape off the varnish adhering to the surface. In the method for producing a glass non-woven fabric base material prepreg, a glass non-woven fabric base material having a varnish attached thereto is passed through and then heated to semi-cure the resin.

The gap of the squeeze roll may be adjusted in advance according to the thickness of the base material, or the thickness may be measured before the resin impregnation and the value may be automatically adjusted. The peripheral speed when reversing the squeeze roll is preferably 10 m / min or less. Even if the roll is not in direct contact with the base material, the base material will be cut if it is rotated at high speed.

[0008]

Function: The squeeze roll 1 is contacted only with the resin impregnated and adhered to the non-woven fabric base material so that the squeeze roll 1 does not directly contact the non-woven fabric base material 2. By doing so, the tension applied to the non-woven fabric base material 2 becomes small and it cannot be cut.

[0009]

【Example】

Example A glass nonwoven fabric substrate (50 g / m ² ) was impregnated with an epoxy resin varnish. The gap between the squeeze rolls 1 was adjusted, the glass nonwoven fabric base material 2 was moved at 6 m / min by reversing at a peripheral speed of 0.5 m / min, and was passed between the squeeze rolls 1 having a diameter of 300 mm. The glass non-woven fabric substrate 2 having a resin adhesion amount of 90% by weight (converted value of solid content of varnish) was semi-cured to the B stage in the drying step. Three semi-cured prepregs were superposed, one glass cloth base prepreg was superposed on each side of the prepreg, and an electrolytic copper foil having a thickness of 18 μm was superposed on the outside of the prepreg, and the mixture was heated and pressed to obtain a copper clad laminate.

Comparative Example A glass nonwoven fabric substrate (50 g / m ² ) was impregnated with an epoxy resin varnish. The gap between the squeeze rolls 1 was adjusted, the glass nonwoven fabric base material 2 was moved at 6 m / min by normal rotation at a peripheral speed of 6 m / min, and was passed between the squeeze rolls 1 having a diameter of 300 mm. The glass non-woven fabric substrate 2 having a resin adhesion amount of 90% by weight (converted value of solid content of varnish) was semi-cured to the B stage in the drying step. Three semi-cured prepregs were superposed, one glass cloth substrate prepreg was superposed on each side of the prepreg, and an electrolytic copper foil having a thickness of 18 μm was superposed on the outside of the prepreg, and the mixture was heated and pressed to obtain a copper clad laminate.

Table 1 compares the thickness deviation, the rate of occurrence of defective scratches, and the warp characteristics of the copper clad laminates obtained from the examples and comparative examples. Table 1 shows variations in the amount of resin adhered to the glass non-woven fabric prepreg before being made into a copper clad laminate.

[0012]

[Table 1]

[0013]

EFFECT OF THE INVENTION Since the resin adhesion amount is adjusted while rotating the squeeze roll of the glass non-woven fabric substrate in reverse, the variation in resin adhesion amount is smaller than that in the case of normal rotation. An excellent rate of occurrence of scratch defects and warpage can be obtained.

[Brief description of drawings]

FIG. 1 is a sectional view of an embodiment of the present invention.

FIG. 2 is a cross-sectional view of an example of a conventional technique.

[Explanation of symbols]

 1 Squeeze roll 2 Glass non-woven substrate 3 Stripped varnish 4 Doctor knife 5 Adhesive varnish

Claims (1)

[Claims] 1. A glass non-woven fabric substrate is impregnated with varnish excessively, and a gap is adjusted so that the adhered varnish is not touched and the substrate is rotated in a direction opposite to the traveling direction of the glass non-woven fabric substrate (doctor). A method for producing a glass non-woven fabric base prepreg, which comprises passing a glass non-woven fabric base to which a varnish is attached between squeeze rolls and then heating to semi-cure the resin.