JPH09208723A - Production of prepreg and production of metal foil-clad laminate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for producing a prepreg hardly causing occurrence of projection in the prepreg and a method for producing a metal foil-clad laminate free from occurrence of crease. SOLUTION: This method for producing a prepreg comprises feeding a substrate 2 comprising glass cloth into a resin liquid 1, interposing and pressing the surface and the rear face of the substrate between a pair of clamping rolls 4 and 4 provided in a resin liquid 1, passing the substrate through a pair of fastening rolls 3 and 3 to control impregnated amount of the resin liquid 1, heating a substrate impregnated with resin by a dryer 5 and semi-curing the impregnated resin. Since impregnated amount is controlled after air attached to the interior of the substrate is driven out of the substrate 2, the method can minimize the size of the projection. This method for producing a metal foil-clad laminate comprises laminating prepreg to afford a laminate and heating a body to be pressed, in which a metal foil is arranged on the outermost layer of the laminate under pressure.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a method for producing a prepreg and a method for producing a metal foil-clad laminate using the prepreg.

[0002]

2. Description of the Related Art A prepreg, which is a material for a metal foil-clad laminate used as a printed wiring board, has a base material impregnated with a resin solution containing an epoxy resin, and the resin impregnated in the base material is semi-cured. It is a thing. An example of a method for manufacturing the prepreg is shown in FIG. Impregnation tank 6 in which base material 12 such as glass cloth is filled with resin liquid 1 containing epoxy resin or the like
And the base material 12 is supplied to the dipping roll 17 in the resin liquid 1.
To change the direction upward and pass between the pair of tightening rolls 13 and 13 provided on the resin liquid surface to control the impregnated amount of the resin liquid by adjusting the gap between the tightening rolls 13 and 13. Then, the resin is semi-cured by heating with a dryer 5 to produce a prepreg.

In recent years, the circuit width has been reduced along with the increase in the density of printed wiring boards, and the weight has been required to be reduced. For the metal foil-clad laminate, a thin metal foil, for example, 20 μm or less is used. A laminated board using this thin metal foil is likely to have wrinkles on the metal foil surface, and if there are such wrinkles, a problem such as disconnection occurs in the circuit.

[0004]

The cause of the wrinkles that occur in the metal foil-clad laminate is the protrusions that often occur on the surface of the prepreg. It is presumed that this protrusion is because the air brought in together with the glass cloth 12 is trapped in the resin and remains as it is without being scraped off by the tightening roll 13.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a method for producing a prepreg in which a metal foil-clad laminate having a reduced number of protrusions generated on the prepreg and no wrinkles. And a method for producing a metal foil-clad laminate using the prepreg.

[0006]

A method of manufacturing a prepreg according to claim 1 of the present invention is directed to a substrate 2 made of glass cloth.
Is supplied to the resin liquid 1, and the front and back surfaces of the base material 2 are pressed by a pair of nipping rolls 4 and 4 provided in the resin liquid 1, and then the base material 2 is placed on the resin liquid surface. It is characterized in that the impregnated resin is semi-cured by passing it between a pair of tightening rolls 3 and 3 installed and controlling the impregnated amount of the resin liquid 1 and then heating with a dryer 5.

A method of manufacturing a prepreg according to a second aspect of the present invention is the method of manufacturing a prepreg according to the first aspect, wherein the gap between the sandwiching rolls 4 and 4 is narrower than the gap between the tightening rolls 3 and 3. Is characterized by.

According to a third aspect of the present invention, there is provided a method for producing a metal foil-clad laminate, wherein the prepreg according to the first or second aspect is a laminated laminate, and a metal foil is placed on the outermost layer of the laminate. It is characterized in that the pressure body is heated and pressurized.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in detail below.
FIG. 1 shows a front view of a main part of an impregnation apparatus used for carrying out a manufacturing method according to an embodiment of the present invention.

The prepreg which is the object of the present invention is obtained by impregnating the base material 2 made of glass cloth with the resin liquid 1 and semi-curing the impregnated resin. Examples of the resin forming the resin liquid 1 include epoxy resin, polyimide resin, unsaturated polyester resin, phenol resin, fluororesin, and the like alone, modified compounds, and mixtures. Also, resin liquid 1
In addition to the resin, a solvent such as dimethylformamide (DMF), methyl ethyl ketone (MEK), acetone, methyl cellosolve, a curing agent, and a filler are appropriately added as necessary.

As shown in FIG. 1, the impregnating device is provided with an impregnating tank 6
The impregnation tank 6 is filled with the resin liquid 1, and the continuously supplied substrate 2 is impregnated with the resin liquid 1. The above-mentioned impregnating device is provided with an impregnating roll 7 that redirects the base material 2 upward, and a pair of sandwiching rolls 4 and 4 on both sides of the base material 2 facing upward, in an impregnation tank 6 filled with the resin liquid 1. . The nip rolls 4 and 4 move in the horizontal direction, and have a structure of pinching both front and back surfaces of the base material 2. Above the liquid surface of the resin liquid 1, a pair of tightening rolls 3 are provided on both sides of the base material 2. The tightening rolls 3 and 3 have a function of controlling the impregnated amount of the resin liquid by adjusting these gaps.

A method of manufacturing a prepreg using the above impregnating device will be described. The base material 2 of glass cloth is continuously supplied to the impregnation tank 6 filled with the resin liquid 1, and the base material 2 is impregnated with the resin liquid 1. The substrate 2 that has been turned upward by the impregnating roll 7 passes between the pair of sandwiching rolls 4 and 4. The nip rolls 4 and 4 pinch the front and back surfaces of the base material 2, and the air adhering inside the base material 2 and adhering to the surface of the base material 2 is expelled to the outside of the base material 2. The resin liquid 1 is impregnated with the air being expelled. The base material 2 impregnated with the resin liquid 1 passes between the tightening rolls 3, 3 provided above the liquid surface of the resin liquid 1. By adjusting the gap between the tightening rolls 3 and 3, the excess resin liquid 1 can be squeezed out from the base material 2 and the desired impregnation amount can be obtained.
The gap between the sandwiching rolls 4 and 4 may be the same as the gap between the sandwiching rolls 3 and 4, but it is preferable to narrow the gap. However, the gap between the nip rolls 4 and 4 should not be too narrow to cause the glass cloth to shift. The sandwich rolls 4, 4,
Also, the tightening rolls 3, 3 rotate as the base material 2 passes. Then, the base material 2 impregnated with the predetermined amount of the resin liquid 1 is heated by the dryer 5. Semi-curing the impregnated resin,
A prepreg is obtained.

The prepreg obtained as described above is used for a metal foil-clad laminate. The metal foil-clad laminate is obtained by stacking the above prepreg cut into a predetermined size to form a laminated body, and heating and pressing a pressure-sensitive body having a metal foil as the outermost layer of the laminated body. The metal foil, for example, copper,
Examples of the material include aluminum and stainless steel, and the thickness thereof is not limited, but the effect of the present invention is remarkable when a thin metal foil having a thickness of 20 μm or less is used. At the time of heating, the body to be pressed is sandwiched between metal plates, inserted into a heating plate, and heated and pressed. A multilayer metal foil-clad laminate can be obtained by laminating the inner layer circuit board via a prepreg to form a laminate.

The above metal foil-clad laminate is used as a printed wiring board by forming a conductor circuit by etching the metal foil provided as the outermost layer.

[0015]

EXAMPLES Examples of the present invention and comparative examples will be described below.

Example 1 A resin liquid containing an epoxy resin as a constituent material was prepared as follows. As the epoxy resin, 90 parts by weight of a brominated bisphenol A type epoxy resin (epoxy equivalent: 500) (hereinafter referred to as "part"), 10 parts of a cresol novolac type epoxy resin (epoxy equivalent: 220), and dicyandiamide (DICY) as a curing agent 5 parts, 30 parts of dimethylformamide (DMF) as a diluting solvent, 30 parts of methyl cellosolve (MC), and 0.2 parts of 2 ethyl 4-methyl imidazole (2E4MZ) as a curing accelerator. The above materials were compounded, further diluted with methyl ethyl ketone (MEK) as a solvent, and the impregnation tank was filled.

The impregnation apparatus shown in FIG. 1 was used. MI as the base material
Using the L-specification standard 7628 type glass cloth (Asahi Schwabel Co., Ltd .: 7628, thickness 0.18 mm), the above base material was continuously supplied to the impregnation tank, and the base material was impregnated with the resin liquid. The gap between the sandwiching rolls was adjusted to 0.23 mm, and the gap between the tightening rolls was adjusted to 0.23 mm. The above base material was turned upward by an impregnation roll, and the front and back surfaces of the base material were sandwiched by the sandwich roll, and then passed through a pair of tightening rolls installed on the resin liquid surface. Then, it was semi-cured by a dryer to obtain a prepreg. The resin content of this prepreg was 38% by weight, and the maximum height of the protrusions on the surface of the prepreg was 20 μm.

Eight of the above prepregs are stacked, one on each side of the prepreg.
Place a pressure plate with 8μm copper foil on a metal plate,
Insert between hot plates. Until the resin impregnated in the prepreg is melted, the temperature is 130 to 135 ° C. and the initial pressure is 10
Perform at a low pressure of kg / cm ² and then pressurize the second step to 30
The temperature of the hot platen was raised to 180 ° C. at kg / cm ² and heated and pressed to completely cure the resin, thereby obtaining a double-sided copper foil-clad laminate having a thickness of 1.6 mm.

Example 2 Except that the gap between the sandwiching rolls of Example 1 was adjusted to 0.20 mm and the gap between the tightening rolls was adjusted to 0.23 mm,
A prepreg was obtained in the same manner as in Example 1. When the height of the protrusions on the surface of the prepreg was measured, it was 13 μm at the maximum. Next, molding was performed in the same manner as in Example 1 to obtain a thickness of 1.
A 6 mm double-sided copper foil-clad laminate was obtained.

Comparative Example 1 The impregnating apparatus shown in FIG. 2 was used. Using the same resin solution and base material as in Example 1, the gap between the tightening rolls was set to 0.
It was adjusted to 23 mm. The above base material was turned upward by an impregnating roll, passed through a pair of tightening rolls installed on the resin liquid surface, and then semi-cured by a dryer to obtain a prepreg. The resin content of this prepreg was 38% by weight, and the maximum height of the protrusions on the surface of the prepreg was 150 μm. Then, it was molded in the same manner as in Example 1 to obtain a double-sided copper foil-clad laminate having a thickness of 1.6 mm.

The occurrence of wrinkles in the obtained copper foil-clad laminates of Examples 1 and 2 and Comparative Example 1 was evaluated. The copper foil surface of the copper foil-clad laminate was visually inspected and the presence or absence of wrinkles was measured. Both sides (n = 100) of 50 copper foil-clad laminates were measured. As shown in Table 1, the copper foil-clad laminates of the examples produced less wrinkles than the comparative examples.

[0022]

[Table 1]

[0023]

The prepreg manufactured by the manufacturing method according to claim 1 or 2 of the present invention presses the front and back surfaces of the base material with a pair of nipping rolls provided in the resin liquid, Since the amount of impregnation is controlled by the pair of tightening rolls after the air adhering to the surface of the base material and carried in is expelled to the outside of the base material, the protrusions can be made smaller. as a result,
The metal foil-clad laminate using this prepreg has few wrinkles on the metal foil surface.

The metal foil-clad laminate obtained by the method for producing a laminate according to claim 3 of the present invention has few wrinkles on the metal foil surface.

[Brief description of drawings]

FIG. 1 is a front view of a main part of an impregnating apparatus used for carrying out a manufacturing method according to an embodiment of the present invention.

FIG. 2 is a front view of a main part of an impregnating apparatus used in a conventional manufacturing method.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Resin liquid 2 Base material 3 Tightening roll 4 Nipple roll 5 Dryer 6 Impregnation tank 7 Impregnation roll

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Claims (3)

[Claims] 1. A base material made of glass cloth is supplied into a resin liquid, and the front and back surfaces of the base material are pressed by a pair of nipping rolls provided in the resin liquid. Passing between a pair of tightening rolls installed on the liquid surface, controlling the impregnated amount of the resin liquid, and then heating with a dryer to semi-cure the impregnated resin. Production method. 2. The method for producing a prepreg according to claim 1, wherein the gap between the sandwiching rolls is narrower than the gap between the tightening rolls. 3. A metal foil-clad laminate comprising: a prepreg according to claim 1 or 2 as a laminated laminate, wherein a pressure-sensitive body having a metal foil as an outermost layer of the laminate is heated and pressed. Manufacturing method.