JP2543099B2 - Laminated board manufacturing method - Google Patents

Description

TECHNICAL FIELD The present invention relates to a method for manufacturing a laminate. More specifically, the present invention relates to a method for manufacturing a laminated board for a printed wiring board, which suppresses a thickness deviation and an abnormal appearance due to a change in resin flow of a prepreg.

(Background Art) Conventionally, in the manufacture of a laminate for a printed wiring board, a prepreg obtained by impregnating a resin such as an epoxy resin, a phenol resin or a polyimide resin into a substrate such as a glass cloth, a glass sheet or paper is used at 20 ° C to It was common to take out what was stored in a constant temperature and humidity chamber at a temperature of 25 ° C and a temperature of 30 to 40% RH or less and use it for forming a laminated plate.

This storage in a constant temperature and humidity chamber is essential for steady operation of the laminated plate manufacturing process and for uniform quality, but on the other hand, due to this difference in storage time, lamination due to moisture absorption and drying. There is an unavoidable problem that a difference in the flow of resin between the plates causes an abnormal appearance of the laminated plate and a large thickness deviation.

Such poor appearance and lack of dimensional stability have been a cause of deteriorating the uniformity of the quality of the laminate and lowering the product yield. Therefore, it has been strongly desired to realize an improved method for manufacturing a laminated board capable of suppressing the appearance defect and the plate thickness deviation during the molding of the laminated board due to the storage of the prepreg.

(Object of the Invention) The present invention has been made in view of the circumstances as described above, and improves the drawbacks of the conventional methods, and the difference in the resin flow,
It is an object of the present invention to provide an improved method for manufacturing a laminated plate, in which the appearance failure and the increase in the plate thickness deviation due to it are suppressed.

DISCLOSURE OF THE INVENTION In order to achieve the above-mentioned object, the method for producing a laminated plate of the present invention, in order to achieve the above object, stacks a required number of prepregs that have been treated at a temperature of 50 ± 2 ° C. for 1 to 2 hours under a reduced pressure of 30 to 50 Torr. It is characterized in that a laminated body in which a metal foil is arranged on the upper surface and / or the lower surface thereof is formed by heating and pressing.

A method for manufacturing a laminated board of the present invention will be described with reference to the accompanying drawings.

FIG. 1 shows an example of the manufacturing method of the present invention as a process flow. As shown in this example, in the manufacturing method of the present invention, (a) for example, the prepreg (1) is thermostatted under the same conditions of 20 ° C. and 40% RH or less, or 25 ° C. and 30% RH as in the conventional case. Stored in the wet chamber (2) for a predetermined time, or without storing (b) the semi-cured dried prepreg (1) is placed in a vacuum chamber (3) such as a vacuum tank or a vacuum tank, and stored at 30 to 50 Torr. The prepreg (1) is treated under a reduced pressure condition at a temperature of 50 ± 2 ° C. for 1 to 2 hours.

(C) Next, the required number of dehumidified prepregs (1) and the metal white (4) to be disposed on the upper surface and / or the lower surface thereof are overlaid, and (d) the obtained laminated body (5) is heated. Press molding.

The type of prepreg used in the production method of the present invention is not particularly limited, and a liquid material of a synthetic resin such as a phenol resin, an epoxy resin, an unsaturated polyester resin, a melamine resin, a polyimide resin, or a fluorine resin is used. Examples include those impregnated with a base material such as glass cloth, polyester cloth, polyamide cloth, aramid fiber cloth, and paper.

For this resin impregnation, it is preferable to impregnate the resin etc. after drying to 40 to 60% by weight.Although most of the liquid material of the resin used is varnish, the fluororesin is in the emulsion state. Will be used.

Further, the impregnation may use not only one type of resin but also a plurality of types. For example, it is also possible to carry out primary impregnation with a melamine resin, improve impregnation properties and flame retardancy, and then carry out secondary impregnation with a phenol resin.
As the resin, a compounded product may be used from the beginning, or a modified resin such as tung oil-modified phenol resin or epoxy-modified polyimide resin may be used.

As the base material, a product having a width of 1 m or 2 m and a thickness of 0.03 to 0.3 mm is generally used. Of course, in this method, this range is not limiting. The glass or resin cloth used as the substrate may be either woven cloth or non-woven cloth, and the paper includes kraft paper, Sonter paper, glass paper and the like.

The thickness of the metal foil to be arranged on the upper surface and / or the lower surface of the required number of prepregs is about 0.018 to 0.0
Metals such as 7 mm of copper, aluminum, iron, zinc, nickel, etc., or alloys thereof, as well as composite foils such as zinc-coated iron can be used. When disposing these metal foils, an adhesive layer may be provided on one surface of the metal foil to improve the adhesive force, if necessary.

1 at a temperature of 50 ± 2 ℃ under vacuum decompression condition of 30 to 50 Torr
The treatment of the prepreg for 2 hours is the most important requirement of the method of the present invention, and when the reduced pressure condition is less than 30 Torr, less than 48 ° C., and less than 1 hour, the treatment effect such as dehumidification is unsatisfactory. If it exceeds 50 Torr and 52 ° C. for 2 hours, on the contrary, the fluidity of the resin at the time of laminating and molding remarkably lowers, and scrapes occur in the molded product, which is not preferable.

This requires treatment at controlled conditions of 30-50 Torr, 50 ± 2 ° C. and 1-2 hours. In this process, the effect of suppressing the appearance defect of the laminated plate and the plate thickness deviation is greatly improved.

Next, the production method of the present invention will be described in more detail with reference to examples. Of course, the present invention is not limited to the examples below.

Example A kraft paper (1 m x 1 m) having a thickness of 0.2 mm was impregnated with a phenol resin varnish having a resin content of 50% by weight so that the resin amount after drying was 50% by weight, and dried to obtain a prepreg. .

8 pieces of this prepreg are piled up, and the thickness of 0.03
A 5 mm single-sided adhesive-attached copper foil was arranged. 1 for the obtained laminated body
The mixture was heated and pressed at a pressure of 00 Kg / cm ² and a temperature of 160 ° C. for 60 minutes. A 1.6 mm thick double-sided copper-clad laminate was obtained. In the formation of this laminated plate, the prepregs that were superposed were those that were treated in a vacuum tank under a reduced pressure of 40 Torr at a temperature of 52 ° C. for 90 minutes.

With respect to the obtained laminated plate, the plate thickness deviation due to the lamination molding was measured at the central portion (A) and the position (B) 5 cm from the end line shown in FIG. The plate thickness was 1.60 mm at the center (A) and 1.55 mm at the end (B). The difference was extremely small as compared with the comparative example described below. It can be seen that the plate thickness deviation is effectively suppressed.

In FIG. 2, l = 1 m and t = 1.6 mm. In addition, almost no defective appearance was observed.

Comparative Example A double-sided copper-clad laminate was obtained in the same manner as in Example without performing treatment of the prepreg under reduced pressure.

 When the plate thickness was measured, the center part (A) was 1.60 mm and the end part (B) was 1.50 mm, and the difference between the two was extremely large.

(Effects of the Invention) As described in detail above, according to the present invention, it is possible to suppress the appearance abnormality and the increase in the thickness deviation caused by the lamination molding caused by the difference in the degree of moisture absorption during the storage until the molding of the prepreg. It is possible to manufacture a laminated plate having good uniformity and product yield.

[Brief description of drawings]

1 (a), (b), (c), and (d) are process drawings showing an example of the manufacturing method of the present invention. FIG. 2 is a cross-sectional view of the laminated plate showing a portion for measuring the plate thickness of the laminated plate. 1 ... prepreg, 2 ... constant temperature and humidity chamber, 3 ... vacuum chamber,
4 ... Metal foil, 5 ... Laminated body.

Claims (1)

(57) [Claims] 1. A required number of prepregs which have been treated under a reduced pressure of 30 to 50 Torr at a temperature of 50 ± 2 ° C. for 1 to 2 hours,
A method for producing a laminated plate, comprising heating and pressurizing a laminated body in which a metal foil is provided on the upper surface and / or the lower surface.