JPH0620775B2 - Molding method for fiber reinforced thermoplastic resin sheet material - Google Patents

Description

TECHNICAL FIELD The present invention relates to a method for molding a sheet-shaped composite material in which a thermoplastic resin such as polypropylene resin is reinforced with long fibers such as glass.

[Prior Art] A long glass fiber reinforced thermoplastic resin sheet material obtained by reinforcing a thermoplastic resin such as polypropylene resin with a long glass fiber is
Since continuous long glass fibers are uniformly dispersed in a layered form, it is widely used as various structural parts because of its physical properties such as high strength.

Therefore, as a conventional method for molding a long glass fiber reinforced thermoplastic resin sheet material, as shown schematically in FIGS. 7 to 11, first, a product for molding a long glass fiber reinforced thermoplastic resin sheet material is used. The glass long fiber reinforced thermoplastic resin sheet material 1 (hereinafter, simply referred to as the sheet material 1) is cut into a predetermined size according to the weight and shape of the sheet, and is heated from both sides by a heating device 2 such as a far infrared heater. 200-22
Heated sheet material 1 heated at 0 ° C. for 4-6 minutes and then heated
The upper mold 5 which is taken out of the heating device 2 and attached to the press machine 3.
And mold 6 including lower mold 6, and molding pressure 100-
The product 7 was obtained by stamping press at 200 kg / cm ² and releasing, and post-processing.

[Problems to be solved by the invention]

By the way, according to the conventional molding method, when the sheet material 1 having a smooth surface is heated to 200 to 220 ° C. by the heating device 2, as shown in FIG. In order to eliminate this fluff by molding and make a molded product with smooth front and back surfaces, 50-100
It is 100 to 2 by a large-sized and heavy press machine of ton.
It must be molded at a high pressure of 00 kg / cm ² .

Therefore, not only the pressing machine needs a considerably large one and the installation area thereof increases, but also the die
Since it is necessary to stamp both the front and back sides of the sheet material to make them smooth surfaces, rather than a simple mold, a considerably high precision is required, which is not suitable for small lot short delivery time production. Was.

The present invention has been made in view of such problems of the conventional technique, and an object thereof is to form a fiber-reinforced thermoplastic resin sheet material in the case of heating and softening the sheet material by a heating device, to form a sheet. The upper and lower sides (front and back) of the material are covered with a covering material such as a canvas or a resin sheet having a peeling effect to eliminate the fluffing caused by the exposure of long glass fibers, and the molding pressure is about one-fifth of the conventional pressure. To provide a molding method for a fiber reinforced thermoplastic resin sheet material that is economical, with a low pressure, a compact press machine, and a simple mold, and that can be used for small lots and short delivery times. It is in.

[Means for solving problems]

For this purpose, the present invention is to cover the upper and lower surfaces of a fiber-reinforced thermoplastic resin sheet material cut into predetermined dimensions corresponding to the shape of the product to be molded, with a covering material such as canvas or resin sheet having a peeling effect. Then, the fiber-reinforced thermoplastic resin sheet material coated with the coating material is heated and softened by a heating device, and then the coating material is peeled off, and then the fiber-reinforced thermoplastic resin sheet material peeled off the coating material is removed. It is characterized by a structure for obtaining a product by press molding.

〔Example〕

An embodiment of the present invention will be described below with reference to FIGS. 1 to 6.

First, a fiber-reinforced thermoplastic resin sheet material 10 such as long glass fibers (hereinafter simply referred to as sheet material 10) is cut into a predetermined size according to the weight and shape of a product to be molded (see FIG. 1). This cutting step is similar to the conventional method.

Next, the upper and lower surfaces (front and back) of the sheet material 10 (preferably the entire surface including the side surfaces) are covered with a covering material 11 such as a thin, preferably thick 0.3 to 0.5 mm canvas or a fluororesin sheet having a peeling effect. (See FIG. 2). This is to reliably prevent fluffing of the long glass fibers 1a (see FIG. 9), which cannot be avoided by the conventional method, in the subsequent heating step by the heating device.

Then, the sheet material 10 coated with the coating material 11 is heated to 200 to 2 from both upper and lower sides by the heating device 12 similar to the conventional device.
It is uniformly heated and softened at 20 ° C. for 3 to 5 minutes (see FIG. 3), then taken out from the heating device 12, and the coating material 11 is rapidly peeled off (see FIG. 4) to be softened by heating. The sheet material 10 'is applied to the upper mold 15 and the lower mold 1 of the press machine 13.
6 Mold including 6 is charged, molding pressure 6-10kg /
A stamping press (see FIG. 5) is performed at cm ^{2 for} a time of 5 to 6 minutes, and the product is subjected to post-processing to obtain a product 17 (see FIG. 6).

In the pressing step, the heat-softened sheet material 10 'is one in which the long glass fibers 1a are not exposed on the front and back surfaces of the sheet material 10' and there is no fluffing. A simple structure that presses against the mold surface of the lower mold 16 is sufficient, and it is not necessary that the female mold 5 corresponds to the male mold 6 that requires high accuracy as shown in FIG. Since it is not necessary to press the glass fiber 1a being pressed with a high pressure to form a smooth surface, 6-10
The pressure is as low as kg / cm ² which is about 1/15 of the conventional pressure.

〔The invention's effect〕

Therefore, according to the present invention, in the molding step of the fiber-reinforced thermoplastic resin sheet material, the entire surface of the fiber-reinforced thermoplastic resin sheet material is coated with a coating material having a peeling effect and heated, and then the coating material is quickly coated. Since it is configured to be peeled off and press-molded, there is no possibility that long glass fibers are exposed to the fiber reinforced thermoplastic resin sheet material to cause fluffing.

Therefore, in order to make the fluffing surface of the long glass fiber a smooth surface, it is necessary to use a considerably large press machine and to press-form with a considerably high molding pressure and a highly accurate mold. In comparison, the molding pressure is as low as about 1 / 15th, the press machine is small, and the mold has a simple structure, and the manufacturing cost is about 1% compared to the conventional product.
It is as cheap as 1/0, has excellent economical efficiency, and is suitable for small lot, short time delivery.

[Brief description of drawings]

1 to 6 are schematic explanatory views showing an example of the molding method according to the present invention, and FIGS. 7 to 11 are schematic explanatory views showing a conventional method. 10 ... Fiber-reinforced thermoplastic resin sheet material 10 '... Fiber-reinforced thermoplastic resin sheet material that has been softened by heating and peeled off the coating material 11 ... Coating material 12 ... Heating device 13 ... Press machine 14 ... Mold 15 …… Upper mold 16 …… Lower mold 17 …… Product

Claims (1)

[Claims] 1. A fiber reinforced thermoplastic resin sheet material cut into a predetermined size corresponding to the shape of a product to be molded is covered with a covering material such as a canvas or a resin sheet having a peeling effect, and the covering is performed. The fiber-reinforced thermoplastic resin sheet material coated with the material is heated and softened by a heating device, and then the coating material is peeled and removed, and then the fiber-reinforced thermoplastic resin sheet material from which the coating material is peeled and removed is press-molded. A method for molding a fiber-reinforced thermoplastic resin sheet material, which comprises obtaining a product.