JP2959348B2 - Resin varnish impregnation method and resin varnish impregnation apparatus - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an impregnating apparatus for impregnating a sheet-like substrate with a resin varnish using a transfer roll, and more particularly to an impregnation method and an impregnation method suitable for producing a prepreg for forming a laminate. Device.

[0002]

2. Description of the Related Art An impregnating method and an impregnating apparatus using the above-mentioned transfer roll is a technique as shown in FIG. The transfer roll 1 is rotated while being partially immersed in the resin varnish 2, and the transferred long sheet-shaped base material 3 is continuously applied to the peripheral surface of the transfer roll 1 above the liquid surface of the resin varnish 2. Contact
Since the resin varnish adheres to the peripheral surface of the transfer roll 1 above the liquid surface of the resin varnish 2 and is lifted up, the sheet-shaped base material in contact with the peripheral surface of the transfer roll 1 3 and the impregnation is performed. Before and after the transfer roll 1, small-diameter holding rolls 4 and 4 ′ are arranged so that the sheet-shaped base material 3 comes into contact with the transfer roll 1. The sheet-like substrate impregnated with the resin varnish in this manner is dried as it is or by further impregnating the resin varnish with a secondary impregnation to obtain a prepreg in which the impregnated resin is in a semi-cured state.

[0003]

In the above prior art,
The resin varnish transferred from the transfer roll to the sheet-shaped substrate gradually penetrates and impregnates to the opposite surface of the substrate,
It is difficult for the resin varnish to sufficiently penetrate to the opposite surface of the substrate. A laminated board formed by heating and press-forming an appropriate number of prepregs obtained by drying a sheet-like base material that does not sufficiently penetrate such a resin varnish has voids or poor moisture resistance due to insufficient resin impregnation. In addition, since the impregnation is not uniform, the warpage of the laminate increases. The problem to be solved by the present invention is to impregnate the resin varnish with a transfer roll so that the resin varnish sufficiently penetrates to the opposite surface of the sheet-like substrate. If impregnation in which the resin varnish has sufficiently penetrated the sheet-like base material has been performed, the above-mentioned voids can be suppressed, the moisture resistance can be improved, and the warpage can be reduced.

[0004]

In order to solve the above-mentioned problems, a method according to the present invention comprises rotating a transfer roll while partially immersing the transfer roll in a resin varnish, and transferring a long sheet-like substrate to be transferred. In the resin varnish impregnation method of continuously contacting the peripheral surface of the transfer roll above the liquid surface of the resin varnish and transferring the resin varnish adhering to the peripheral surface of the transfer roll to a sheet-shaped substrate, the impregnation is performed. Until the resin varnish permeates the opposite surface of the sheet-like substrate, a solvent-impermeable backup material is adhered to the opposite surface of the sheet-like substrate away from the peripheral surface of the transfer roll. The impregnating apparatus for carrying out the above method includes a solvent-impermeable backup roll as a solvent-impermeable backup material. The backup roll is in close contact with the sheet-like substrate away from the transfer roll peripheral surface from the opposite surface, but can be backed up until the impregnated resin varnish permeates the opposite surface of the sheet-like substrate. It is characterized by having a large diameter sufficient. The backup roll may have its peripheral surface wet with a solvent.

[0005]

When the resin varnish transferred from the transfer roll to the sheet-like base material penetrates into the base material, the solvent easily permeates first. If the opposite side of the substrate is exposed to the air after the sheet-like substrate is separated from the transfer roll, only the solvent will volatilize from the opposite side of the substrate first, and the resin component having increased viscosity will be removed. It will not be able to penetrate to the opposite side of the substrate. In the method and the apparatus according to the present invention, the backup material (backup roll) is brought into close contact with the opposite surface of the sheet-shaped substrate away from the transfer roll to prevent the solvent from volatilizing, so that the increase in viscosity can be prevented. The resin can be sufficiently penetrated to the opposite surface of the substrate. If the peripheral surface of the backup roll is wetted with the solvent, the base material can be wetted from the side of the backup roll, so that the penetration of the resin component can be further promoted.

[0006]

【Example】

Example 1 As shown in FIG. 1, a transfer roll 1 was rotated while partially immersed in a resin varnish 2, and a long sheet-like base material 3 (glass nonwoven fabric) transferred was transferred to a resin varnish 1 (epoxy resin). The resin varnish adhering to the peripheral surface of the transfer roll 1 was continuously brought into contact with the peripheral surface of the transfer roll 1 above the liquid level of the varnish), and transferred to the sheet-shaped substrate 3 for impregnation. A stainless steel backup roll 5 (750 mm in diameter) was adhered to the sheet-like base material 3 distant from the peripheral surface of the transfer roll 1 from the surface opposite to the surface in contact with the transfer roll 1. At a transfer speed of the sheet-like substrate 3 of 7 m / min, the sheet-like substrate 3 comes into close contact with the backup roll 5 so as to allow a sufficient time for the impregnated resin varnish to penetrate into the opposite surface of the sheet-like substrate 3. Distance was set to 500 mm. The distance in which the sheet-shaped substrate 3 is in close contact with the backup roll 5 is determined by changing the contact angle of the sheet-shaped substrate 3 with the backup roll 5 by moving the adjustment roll 6. The prepreg was prepared by further impregnating the sheet-like substrate having undergone the above steps with an epoxy resin varnish by a dipping method and drying. This prepreg is used as a core material, and a glass woven epoxy resin prepreg prepared separately is arranged on both surfaces, and a copper foil is arranged on the outermost surface, and a 1.6 mm thick sheet is formed by heating and pressing. A double-sided copper-clad laminate was manufactured. Table 1 shows the characteristics of the double-sided copper-clad laminate.

Conventional Example 1 As shown in FIG. 3, the sheet-like base material 3 is pressed by small-diameter holding rolls (diameter 100 mm) 4, 4 'arranged before and after the transfer roll 1, and A prepreg was prepared in the same manner as in Example 1 except that the prepreg was in contact with the transfer roll 1. The distance in which the sheet-like base material 3 distant from the transfer roll 1 is in close contact with the press roll 4 'is about 80 mm.
A double-sided copper-clad laminate was manufactured in the same manner as in Example 1, and the characteristics are shown in Table 1.

[0008]

[Table 1]

Example 2 A prepreg was prepared by impregnating a glass woven fabric with an epoxy resin varnish and drying by the method and apparatus described in Example 1. This prepreg was heated and pressed to produce a laminate. Table 2 shows the number of voids (within an area of 20 mm ² ) generated in the prepreg and the laminate.

Example 3 In the method and apparatus described in Example 1, the peripheral surface of the backup roll 5 was wet with methyl ethyl ketone, a glass woven fabric was impregnated with an epoxy resin varnish, and dried to prepare a prepreg. This prepreg was heated and pressed to produce a laminate. Table 2 shows the number of voids (within an area of 20 mm ² ) generated in the prepreg and the laminate.
It was shown to. The means for wetting the peripheral surface of the backup roll 5 with methyl ethyl ketone is, for example, as shown in FIG. The felt material 7 is brought into contact with the backup roll 5, and methyl ethyl ketone is dropped from the nozzle 8 to be included in the felt material 7. Then, the methyl ethyl ketone contained in the felt material 7 is applied to the peripheral surface of the rotating backup roll 5. In addition, means for directly spraying methyl ethyl ketone on the peripheral surface of the backup roll or means for transferring methyl ethyl ketone to the peripheral surface of the backup roll by a roll coater method may be employed.

Conventional Example 2 A prepreg was prepared by impregnating a glass woven fabric with an epoxy resin varnish and drying by the method and apparatus described in Conventional Example 1. This prepreg was heated and pressed to produce a laminate. Table 2 shows the number of voids (within an area of 20 mm ² ) generated in the prepreg and the laminate.

[0012]

[Table 2]

[0013]

According to the method and apparatus according to the present invention,
The solvent content of the resin varnish transferred from the transfer roll to the sheet-shaped substrate is suppressed for a while to keep the solvent varnish from penetrating into the substrate, keeping the viscosity of the resin varnish low, and improving the impregnation of the resin varnish. Can be enhanced. When a prepreg in which the resin varnish has sufficiently penetrated uniformly is used for forming a laminate, a laminate having excellent moisture resistance and small warpage can be manufactured. If the peripheral surface of the backup roll is wetted with a solvent to suppress the solvent content of the resin varnish from evaporating for a while, the penetration of the resin varnish is further promoted,
The generation of voids in the prepreg and the laminate can also be suppressed.

[Brief description of the drawings]

FIG. 1 is an explanatory view showing one embodiment of impregnation of a resin varnish with a transfer roll according to the present invention.

FIG. 2 is an explanatory view showing another embodiment of impregnation of a resin varnish with a transfer roll according to the present invention.

FIG. 3 is an explanatory view showing one example of impregnation of a resin varnish with a conventional transfer roll.

[Explanation of symbols]

 1 is a transfer roll 2 is a resin varnish 3 is a sheet-like base material 4 is a holding roll 5 is a backup roll 6 is an adjusting roll 7 is a felt material 8 is a nozzle

Claims (5)

(57) [Claims] A transfer roll is rotated while partially immersed in a resin varnish, and a long sheet-like base material to be transferred is continuously formed on a peripheral surface of the transfer roll above a liquid surface of the resin varnish. In the method of impregnating a resin varnish that abuts and transfers the resin varnish adhering to the peripheral surface of the transfer roll to the sheet-shaped substrate, the transfer is performed until the impregnated resin varnish permeates the opposite surface of the sheet-shaped substrate. A method for impregnating a resin varnish, characterized in that a solvent-impermeable backup material is adhered to the opposite surface of the sheet-like substrate away from the roll peripheral surface. 2. The method according to claim 1, wherein a rotating roll is used as a backup material. 3. A method for impregnating a resin varnish according to claim 2, wherein the peripheral surface of the rotating roll is wetted with a solvent. 4. The transfer roll is rotated while partially immersed in the resin varnish, and the transferred long sheet-like base material is continuously applied to the peripheral surface of the transfer roll above the liquid level of the resin varnish. In a resin varnish impregnation device that abuts and transfers the resin varnish adhering to the transfer roll peripheral surface to the sheet-shaped substrate, the resin varnish is in close contact with the sheet-shaped substrate remote from the transfer roll peripheral surface from the surface opposite to the impregnated surface. The peripheral surface to be provided is provided with a solvent-impermeable backup roll, and the diameter of the backup roll is set to be large enough to be able to back up until the impregnated resin varnish penetrates to the opposite surface of the sheet-shaped substrate. Resin varnish impregnating device. 5. The resin varnish impregnating apparatus according to claim 4, further comprising means for wetting the peripheral surface of the backup roll with a solvent.