JPH01110946A - Manufacture of laminated sheet - Google Patents

Abstract

PURPOSE:To control a defective external appearance and a deflection of a plate thickness at the time of molding of a laminated sheet to be followed by storage of prepreg, by making use of the prepreg treated at a specific temperature for 1-2 hours under depressurization. CONSTITUTION:Prepreg 1 is put into a vacuum chamber 3 and treated at a temperature of 50+ or -2 deg.C for 1-2 hours under a depressurizing condition of 30-50Torr. A necessary number of sheets of prepreg 1, to which dehumidification treatment has been performed, and a metallic foil 4, which is arranged to the top and/or the bottom of the prepreg 1, are superposed upon each other and an obtained laminated body 5 is molded through heating and depressurization. A control effect of a defective external appearance and deflection of a plate thickness of a laminated sheet is improved drastically, in the dehumidification treatment.

Description

DETAILED DESCRIPTION OF THE INVENTION (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 laminate for a printed wiring board that suppresses board thickness deviations and appearance abnormalities due to changes in prepreg resin flow.

(Background technology) Conventionally, in rJI construction of laminated boards for printed wiring boards,
Epoxy resin on base materials such as glass cloth, glass sheet, paper, etc.
Prepreg impregnated with resin such as phenol resin or polyimide resin is heated at a temperature of 20°C to 25°C and 30% to 40% R.
Generally, materials stored in a constant temperature and humidity chamber under conditions of H or less were taken out and used for forming laminates.

Storage in a constant temperature and humidity chamber is essential for steady operation and uniform quality in the laminate manufacturing process, but on the other hand, due to the difference in storage time, moisture absorption and dryness may occur. As a result, a difference occurs in the flow of resin in the laminate, resulting in abnormal appearance of the laminate and unavoidable problems such as an increase in thickness deviation.

Such poor appearance and lack of dimensional stability reduce the uniformity of the quality of the laminate and cause poor product yield. For this reason, there has been a strong desire to realize an improved method for manufacturing a laminate that can suppress appearance defects and thickness deviations during laminate forming that occur during prepreg storage.

(Object of the invention) This invention was made in view of the above circumstances, and it improves the drawbacks of the conventional method and suppresses the difference in resin flow and the resulting poor appearance and increase in plate N deviation. , aims to provide an improved method for manufacturing laminates.

(Disclosure of the Invention) In order to achieve the above object, the method for producing a laminate of the present invention is to produce a laminate under reduced pressure of 30 to 50 Torr.
The method is characterized in that a required number of prepregs treated at a temperature of ±2° C. for 1 to 2 hours are piled up, and a laminate is formed by heating and pressing, in which metal foil is arranged on the upper and/or lower surfaces.

A method for manufacturing a laminate according to the present invention will be described with reference to the attached drawings.

FIG. 1 shows a process flow of an example of the manufacturing method of the present invention. As shown in this example, in the manufacturing method of the present invention, (a) For example, 20° C. and 40% RH or less as in the conventional case, or 25° C. and 30% RH
Prepreg (1) is stored in a thermostatic chamber (2) for a predetermined period of time under conditions of H or less, or (b)
The semi-hardened prepreg (1) is put into a vacuum chamber (3) such as a vacuum tank or a vacuum tank, and heated to a temperature of 30 to 50'I'or
Prepreg (1) was heated to 50±
Treat with afI for 1-2 hours at a temperature of 2°C.

(C) Next, this dehumidified prepreg (1)
(d) The obtained laminate (5) is heated and press-molded.

The type of prepreg used in the manufacturing method of this invention is not particularly limited, and includes phenolic resin,
Liquid synthetic resins such as epoxy resins, unsaturated polyester resins, melamine resins, polyimide resins, and fluororesins,
Glass cloth, polyester cloth, polyamide cloth, aramid i
For example, a material obtained by impregnating a base material such as textile cloth or paper can be exemplified.

Regarding this resin impregnation, the resin etc. after drying is 40 to 60%
It is preferable to impregnate the resin in an amount of % by weight, and most of the liquid resins used are in the form of fess, but the fluororesin is used in the form of an emulsion.

Furthermore, impregnation is not limited to one type of resin, but may also be performed using multiple types of resin. For example, after primary impregnation with melamine resin to improve impregnation and flame retardancy, secondary impregnation with phenolic resin. It is also possible to do so. v
As the IJ resin, a blended product may be used from the beginning, or a modified resin such as tung oil-modified phenol resin, Evo, or xy-modified polyimide resin may be used.

The base material generally has a width of 1 m or 2 m,
Use a product with a thickness of 0.03 to 0.3w. Of course, in this method, this range is not limited.

The glass or resin cloth used as the base material may be either woven fabric or non-woven fabric, and examples of paper include kraft paper,
Also includes sontar paper, glass paper, etc.

The thickness of the metal foil to be placed on the upper and/or lower surfaces of the required number of prepregs is approximately 0.018~
Foils of metals such as aluminium, iron, nickel, or alloys thereof, or even composites such as zinc-coated iron can be used. When disposing these metal foils, an adhesive layer may be provided on one side of the metal foil to improve adhesive strength, if necessary.

The treatment of the prepreg at a temperature of 2° C. above 50° C. for 1 to 2 hours under vacuum conditions of 30 to 50 Torr is the most important requirement of the method of the present invention;
If the heating time is less than r, 48°C, or even less than 1 hour, the treatment effect such as dehumidification will be insufficient, and the temperature will be 50Torr, 52
If it exceeds 12 hours at °C, on the contrary, the fluidity of the resin during lamination molding will be significantly reduced and the molded product will become smeared, which is not preferable.

30-50Torr, temperature of 50±2'C and 1
This necessitates treatment under controlled conditions of ~2 hours. In this treatment, the effect of suppressing appearance defects of the laminate and plate N deviation is greatly improved.

Next, the manufacturing method of the present invention will be explained in more detail with reference to Examples. Of course, the invention is not limited to the following examples.

Example: Kraft paper (1 m x 1 m) with a thickness of 0.2 cm was coated with a resin content of 50% by weight so that the resin amount after drying was 50% by weight.
A prepreg was obtained by impregnating a phenolic resin face and drying it.

Stack these 8 sheets of prepreg and apply a thickness of 0.0 on the top and bottom surfaces.
A 35 nn copper foil coated with adhesive on one side was provided. The obtained laminate was heated at a pressure of 100+r/aJ and a temperature of 160°C.
The molding was carried out under heat and pressure for 0 minutes. A double-sided copper-clad laminate having a thickness of 1.6 mm was obtained. In forming this laminate, the stacked prepregs were heated at 40'T”orr in a vacuum tank.
The sample was treated under reduced pressure at 52° C. for 90 minutes.

Regarding the obtained laminate, the central part (A) shown in Fig. 2
And the plate thickness deviation due to lamination molding at a position (B) 5 cm from the edge line was measured. The plate thicknesses were 1.60+tm at the center (A) and 1.55++n+ at the ends (B).The difference was extremely small compared to the comparative example described next. It can be seen that the difference in plate thickness per load is effectively suppressed.

In addition, in FIG. 2, fJ = 1 rn, t = 1.
6 matters. Moreover, almost no defects in appearance were observed.

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

When the plate thickness was measured Central area (A) 1.60 city End (B) 1.50+n+ The difference between the two was extremely large.

(Effects of the Invention) As explained in detail above, this invention has improved quality by suppressing appearance abnormalities and plate thickness deviations caused by laminated molding caused by differences in the degree of moisture absorption during prepreg storage before molding. It becomes possible to manufacture a laminate with good uniformity and product yield.

[Brief explanation of the drawing]

FIGS. 1(a), (b), (c), and (d) are process diagrams showing an example of the manufacturing method of the present invention. FIG. 2 is a cross-sectional view of the laminate showing a portion where the thickness of the laminate is measured. DESCRIPTION OF SYMBOLS 1... Prepreg, 2... Constant temperature and humidity chamber, 3... Vacuum chamber, 4... Metal foil, 5... Laminated body. Agent Patent Attorney Toshi Nishizawa Smile 1
Figure (C) 0000ma

Claims (1)

[Claims] (1) Under reduced pressure of 30 to 50 Torr, 50 ± 2
1. A method for manufacturing a laminate, which comprises stacking a required number of prepregs treated at a temperature of 1 to 2 hours at a temperature of .degree.