JPH0689161B2 - Method for producing resin-impregnated base material - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a method for producing a resin-impregnated base material for a laminated plate, which is capable of preventing misalignment and blurring during molding and has excellent heat resistance.

BACKGROUND ART Conventionally, a resin-impregnated base material is manufactured by impregnating a base material with a resin varnish and drying, and a laminate is manufactured by heat-press molding a plurality of the resin-impregnated base materials. Bubbles remain in the resin-impregnated base material, and there are unimpregnated parts of the resin varnish, and the fluidity of the resin is poor during laminating molding, causing scratches. However, the heat resistance and humidity resistance were inferior.
In order to prevent this blur, the amount of resin impregnated is increased or the fluidity of the resin is increased, but in this case, misalignment occurs during molding, resulting in poor moldability.

Further, a pressure roll has been adopted to eliminate bubbles and non-impregnated portions in the resin-impregnated base material, or ultrasonic impregnation has been performed, but the effect was poor. Furthermore, it is impregnated under vacuum, but it is difficult to make it continuous by this method, and even if it is made continuous, air inflow is large and the power cost becomes large, the consumption of sealing parts etc. is severe, and the base material Since pressure is applied by a roll, misalignment is likely to occur, warping and twisting increase, and the device is large and expensive. Furthermore, with any of these methods, it is possible to obtain the resin-impregnated base material with the smallest number of unimpregnated parts and bubbles of about 300 / square inch, and it is impossible to prevent misalignment and blurring during molding. there were.

[Object of the Invention] The present invention has been made in view of the above circumstances, and an object of the present invention is to eliminate the residual air bubbles of a resin-impregnated base material and the unimpregnated portion of a resin varnish, thereby generating or fading. It is an object of the present invention to provide a method for producing a resin-impregnated base material which can prevent positional displacement at the time and is excellent in moldability.

DISCLOSURE OF THE INVENTION In the method for producing a resin-impregnated base material of the present invention, the base material 1 is applied to the solvent 2 that has been subjected to the vacuum defoaming treatment after the solvent 2 alone has been defoamed under reduced pressure.
Is preliminarily impregnated, and then the substrate 1 preliminarily impregnated with the solvent 2 that has been subjected to the vacuum degassing treatment is impregnated with the resin varnish 3 that has not been vacuum degassed, and then dried. With this configuration, the above object is achieved.

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

As the base material 1 used in the present invention, it is possible to employ paper, a cloth or a non-woven fabric formed of organic fibers, or a cloth or a non-woven fabric obtained by spinning or blending inorganic fibers such as glass and asbestos. Use a thickness in the range of 0.10 to 0.30 mm.

The base material 1 is pre-impregnated with the solvent 2 after degassing under reduced pressure. This solvent 2 is compatible with the solvent for preparing the resin varnish 3, and various resin solvents such as methyl cellosolve, methyl alcohol, acetone, methyl ethyl ketone, and dimethylformamide can be adopted, but the vapor pressure at room temperature is 150 mmHg. The following are preferred. As shown in FIG. 1, the solvent 2 is depressurized at 150 Torr or more while being stirred in a decompression chamber 4, and is sent to a solvent impregnation tank 6 by a solvent delivery pump 5. The solvent 2 is circulated from the solvent impregnation tank 6 to the decompression chamber 4 by the circulation pump 7. The base material 1 is fed into the solvent impregnation tank 6 to impregnate the solvent 2. The impregnation time is 10 seconds or more, though it depends on the material of the base material 1, the configuration such as the thickness, and the like.

Next, the resin 1 impregnated with the solvent 2 such as vacuum degassing is sent to the resin varnish tank 8 to impregnate the resin varnish 3. The resin of the resin varnish 3 is not particularly limited, and an epoxy resin, a polyimide resin or a modified product thereof, a thermosetting resin such as a phenol resin or an unsaturated polyester resin,
Alternatively, a thermoplastic resin can be used. The resin varnish 3 is prepared by appropriately selecting and mixing a curing agent, a curing accelerator, a reactive diluent, a flexibility-imparting agent and the like with these resin raw materials. The solid content concentration is usually 60 to 75 wt%. The impregnation time is not particularly limited. The base material 1 impregnated with the resin varnish 3 is squeezed between the pressure rolls 9 so as to have a predetermined resin content, then sent to a drying chamber and dried to obtain a so-called B-stage resin-impregnated base material. Before dipping the base material 1 in the resin varnish tank 8, the solvent 2 and the resin varnish 3 may be replaced by impregnating the resin varnish 3 from one side of the base material 1 with the kiss roll 10. The resin-impregnated base material thus obtained has a non-impregnated portion and the number of bubbles of 20 / square inch. Such a resin-impregnated base material with few voids can be produced because the solvent 2 subjected to degassing under reduced pressure has an air-dissolving power, and the base material 1 is impregnated with the solvent 2 to remove the air in the base material 1. It is possible to dissolve and reduce the residual air, and at the stage where the resin varnish 3 is impregnated into the base material 1 impregnated with the solvent 2 subjected to the vacuum defoaming treatment, the varnish concentration in the base material 1 is A concentration gradient is formed in which the central portion becomes lower than the outer portion, and the resin varnish 3 impregnated at the time of drying has a low viscosity due to heating, and a diffusion phenomenon occurs in an attempt to eliminate the concentration difference. It can be inferred that a convection phenomenon occurs because the solvent evaporates, and as a result, the resin varnish 3 and the solvent 2 having an air-dissolving power pass around the residual air in the base material 1 to accelerate the air absorption.

This resin-impregnated base material is stacked in a plurality of layers, and metal foil such as copper foil is stacked on both sides or one side of the base material. Usually, for example, the temperature is 170 ° C., the pressure is 40 kg / cm ² , and the heating and pressure molding is performed for 60 minutes. Then, a metal foil-clad laminate is manufactured. In addition, it can also be used for laminated molding with a so-called double belt.

Next, examples of the present invention will be specifically described.

(Example) Methyl cellosolve was subjected to a defoaming treatment at a reduced pressure of 20 to 25 Torr for 30 minutes, and a plain woven glass cloth (thickness 0.18 mm, weight 200 g / m ² , epoxysilane treatment agent adhesion amount 0.08) was applied to the treated methyl cellosolve. wt /%) was soaked for 15 seconds.

Then, one side of the glass cloth impregnated with the solvent was impregnated with a resin varnish having a solid content concentration of 70 wt% by a kiss roll to replace the solvent with the resin varnish. After that, the same resin varnish was impregnated with the base material, and the resin content after drying was 45%.
The resin-impregnated base material was obtained by squeezing with a pressure roll so as to have wt% and then drying.

The total amount of unimpregnated parts and bubbles of this resin-impregnated base material was 20 pieces / square inch.

Eight sheets of this resin-impregnated base material were stacked, copper foil was stacked on both sides, and heat and pressure molding was performed at a temperature of 170 ° C., a pressure of 40 kg / cm ² , and a time of 60 minutes. There was no scratch on the substrate.

(Comparative Example 1) A resin-impregnated base material was produced in the same manner as in Example, except that methylcellosolve was not subjected to degassing under reduced pressure. The total number of unimpregnated parts and bubbles was 1000 / parallel inch.

When this resin-impregnated base material was subjected to lamination molding in the same manner as in the example, molding deviation occurred.

(Comparative Example 2) A resin-impregnated base material was produced in the same manner as in Comparative Example 1 except that the resin content was 42 wt%.

When this resin-impregnated base material was subjected to lamination molding in the same manner as in the example, there was no molding deviation, but a blur was generated.

[Effect of the Invention] The conventional method is a method in which a solvent for preliminarily impregnating a base material and a resin varnish for impregnating the base material and then dried are subjected to degassing under reduced pressure. The device inevitably becomes large in size, and maintenance is difficult.

However, in the present invention, the substrate was pre-impregnated with the solvent decompressed under reduced pressure after pre-impregnating the substrate with the solvent decompressed under reduced pressure, and then the substrate pre-impregnated with the solvent decompressed under reduced pressure. The material is impregnated with resin varnish that has not been subjected to vacuum defoaming treatment and dried, that is, only the solvent is used that has been subjected to vacuum defoaming treatment, but the resin varnish to be impregnated is not subjected to vacuum defoaming treatment. Since it is a manufacturing method that uses a thing, the equipment used for that manufacturing method does not become larger than the equipment of the conventional manufacturing method, maintenance is easy to manage, and it is economically efficient. A good manufacturing method is obtained.

Moreover, according to the present invention, the residual air in the base material can be reduced by the air-dissolving power of the solvent and the resin varnish, and the unimpregnated part and bubbles of the base material can be reduced. There is an advantage that it is possible to prevent the positional deviation during molding and is excellent in moldability.

Further, according to the present invention, there is an advantage that a laminated plate excellent in heat resistance and moisture resistance can be manufactured without causing a blur in a product.

[Brief description of drawings]

FIG. 1 is a schematic view showing an example of an apparatus for carrying out the present invention, in which 1 is a substrate, 2 is a solvent, 3 is a resin varnish, and 4 is a solvent.
Is a decompression chamber, 5 is a solvent feed pump, 6 is a solvent impregnation tank, 7 is a circulation pump, 8 is a resin varnish tank, 9 is a pressure roll, and 10 is a kiss roll.

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Innovator Shinji Hosoki, 1048 Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Works, Ltd. (56) JP, B2)

Claims (1)

[Claims] 1. A substrate is preliminarily impregnated with the solvent decompressed under reduced pressure, which is then preliminarily impregnated with the solvent decompressed under reduced pressure. A method for producing a resin-impregnated base material, which comprises impregnating a resin varnish that has not been subjected to defoaming treatment and drying the resin varnish.