JPS5848333B2 - How do you know what to do? - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing a fiber-reinforced thermoplastic resin plate, and particularly to a method for producing the plate by extrusion molding.

Conventionally, a fiber reinforced thermoplastic resin plate is produced by mixing a thermoplastic resin with a fiber reinforcing material, supplying the mixture to an extruder, melting and kneading it, and extruding it into a plate from a mold attached to the tip of the extruder. A method of manufacturing is known.

However, the conventional method as described above has the following drawbacks.

That is, first, the reinforcing fibers contained in the thermoplastic resin are poorly dispersed in the resin.

Reinforcing fibers are usually bundles of single fibers, but...
The bundled reinforcing fibers do not easily disperse uniformly in the resin even when the resin is melted and mixed, and tend to exist between the bundles. It is difficult to manufacture a strong plate-shaped body.

Next, because the reinforcing fibers are arranged in the extrusion direction during the extrusion process, even though the obtained plate-shaped body may have high strength in the extrusion direction, the strength in the direction perpendicular to the extrusion direction does not improve or on the contrary decreases. do.

For this reason, the resulting plate-like body does not have uniform strength, and only a plate-like body with directional strength can be obtained.

The present invention has been made in order to improve the drawbacks of the conventional methods as described above, and it is possible to ensure that the distribution of reinforcing fibers in the resin is uniform and that there is no directionality in the dispersion state of the reinforcing fibers. Therefore, the aim is to manufacture a thermoplastic resin plate-like body in which the reinforcing effect of fibers is effective.

Therefore, in the present invention, a heated and melted thermoplastic resin containing reinforcing fibers is passed through an annular gap formed between a relatively rotating or inverted shaft and an outer mold, and then The gist of the present invention is a method for manufacturing a fiber-reinforced thermoplastic resin plate, which is characterized by feeding the plate into a mold and extruding it.

The reinforcing fiber used in the present invention is preferably one that has a property of not degrading even at the temperature at which the resin is heated and melted and is strong, and also has good adhesion to the thermoplastic resin. It is.

Specific examples of the reinforcing fibers include glass fiber,
Examples include inorganic fibers such as carbon fibers and boron fibers, and organic fibers such as fibers made of hemp, cotton, polyamide, and polyester.

Regarding the length of reinforcing fibers, if extremely short short fibers are used, no reinforcing effect will be obtained, so those having a length of 1 L or more are usually used, and long fibers are particularly preferred.

Further, the above-mentioned reinforcing fiber may be a single fiber, or may be a bundle of a plurality of single fibers.

Next, as the thermoplastic resin used in the present invention, ordinary resins used in extrusion molding are suitably used, such as polyethylene, polypropylene, polystyrene, polyvinyl chloride, polyamide, polyester, polycarbonate, etc. vinyl chloride copolymer,
Examples include ethylene-propylene copolymer, ethylene-vinyl acetate copolymer, styrene-acryloni-1-lyl copolymer, and the like.

Further, in the present invention, two or more of the above-mentioned resins may be used as a mixture, and it is also possible to form a foam by using a mixture of the resin and a foaming agent.

Examples of the blowing agent include azodicarbonamide, azobisisobutyronitrile, sodium bicarbonate, nitrogen gas, carbon dioxide, propane, butane, pentane, chlorofluorohydrocarbons, and the like.

The reinforcing fibers and thermoplastic resin described above may be mixed in advance, or they may be supplied separately to a device that can be suitably used in the present invention, which will be described later, and then mixed in the device described in L. Also good.

Next, the method of the present invention will be explained in more detail with reference to the drawings showing an embodiment of the apparatus preferably used in the present invention.

In the figure, 1 is an ordinary extruder, which is composed of an extrusion tube 4, a screw 3, a crosshead 5, and a raw material supply port 2. Thermoplastic resin is supplied to the extruder 1 from the raw material supply port 2, and is heated and melted. The mixture is kneaded and fed through a crosshead 5 and a communicating pipe 6 to a subsequent extruder.

The latter stage extruder comprises an outer mold 7 and a shaft 8, and the outer mold 7 and shaft 8 are arranged to form an annular gap 81, and in the illustrated apparatus, the shaft 8 is connected to a drive device 13. It's being rotated.

A large number of pores 10 provided along the cross-sectional shape of the annular slit 81 are communicated with the annular slit 81, and a continuous glass fiber bundle 12 is supplied to the annular slit 81 through each pore 10. Ru.

11 is a guide roller that guides the glass fiber bundle 12.

The thermoplastic resin heated and melted in the extruder 1 is supplied to the annular slit 81 through the communication pipe 6 as described above, and together with the glass fiber bundle 12 supplied to the annular slit 81 at the same time, the thermoplastic resin is heated and melted in the extruder 1 by back pressure from the extruder 1. Extruded sequentially.

Since the shaft 8 is rotating, the molten resin and glass fiber bundle 12 present in the annular gap 81 are subjected to a shearing force perpendicular to the extrusion direction, and as a result, the glass fiber bundle 12 is loosened into pieces. and are arranged in a direction diagonal to the extrusion direction.

The loosened glass fibers are uniformly dispersed in the resin, and the molten resin containing the glass fibers arranged diagonally with respect to the extrusion direction is then molded into a plate-shaped body or a mold 15, which remains in a molten state. supplied to

The annular slit 81 and the plate molding die 15 are communicated with each other by a passage 14 whose cross-sectional shape continuously changes,
The molten resin containing glass fibers is continuously shaped into a plate-like body from a cylindrical body.

The plate-shaped body 16 extruded from the plate-shaped body or die 15 is then passed through a cooling sizing water tank 17 and taken up by a take-up roll 18 to be manufactured into a product.

Although not shown in the drawings, the extruder 1, the outer mold 7, and the plate molding die 15 are all equipped with heating means to keep the resin in a molten state.

Further, although the shaft 8 is rotated in the above-described embodiment, it may be reversed, in which case the direction in which the glass fibers are arranged can be alternately changed.

Furthermore, in the embodiment described in -h, the outer mold 7 is fixed and the shaft 8 is rotated, but instead, the outer mold 7 is rotated and the shaft 8 is fixed, or both the outer mold T and the shaft 8 are rotated in opposite directions. It is also possible to rotate or invert.

Further, in the above-mentioned embodiment, an extruder 1 is separately provided in order to knead the resin while heating and melting it.
Although the resin is supplied to the extruder 1, it is also possible to integrate the extruder 1 with an extruder having an annular gap 81.

In the present invention, the plate-shaped object molding die 15 is not necessarily limited to a mold for shaping into a flat plate shape, but a plate-like object for forming a plate-like object having an irregular cross section such as a U-shape or a wave shape. It is also possible to use a body or mold.

As explained in detail above, in the present invention, in the annular gap formed between the relatively rotated or reversed shaft and the outer mold,
Since the process of passing the heated and melted thermoplastic resin containing reinforcing fibers is adopted, the reinforcing fibers in the resin pass through the annular gap at right angles to the extrusion direction due to rotation or reversal action. Due to the shearing force in the direction, the arrangement direction becomes oblique to the extrusion direction.

If the reinforcing fibers are bundled, they will be loosened by the shearing force and uniformly dispersed in the resin.

By improving the distribution and arrangement direction of the reinforcing fibers in the resin, the plate-shaped body extruded from the plate-shaped body mold has a high strength and is not directional, making it a good product. It is of high value.

Therefore, it is possible to produce a plate-like body with greater strength compared to the conventional method of producing a plate-like body by simply supplying reinforcing fibers and resin to an extruder and extrusion molding.

[Brief explanation of drawings]

FIG. 1 is a partially cutaway top view showing an embodiment of a device suitable for use in the present invention. In the figure, the names of the main parts are as follows. 7... Outer mold, 8... Shaft, 12...
... Reinforcement fiber (glass fiber bundle), 81 ... Annular slit, 15 ... Plate-shaped body mold.

Claims (1)

[Claims] 1. After passing a heated and melted thermoplastic resin containing reinforcing fibers through an annular gap formed between a shaft and an outer mold that are relatively rotating or inverted, this is formed into a plate-shaped body. A method for manufacturing a fiber-reinforced thermoplastic resin plate, characterized by feeding the fiber into a mold and extruding it.