JPH079533A - Manufacturing method of composite sheet - Google Patents

Abstract

(57) [Summary] [Object] To provide a method for producing a reinforcing fiber-containing composite sheet with little difference in strength between the extrusion direction and other directions. [Structure] A composition comprising reinforcing fibers and a thermoplastic resin is heated and melted, supplied to two or more flow paths, and the molten compositions are merged to extrude a sheet, thereby disturbing the orientation of the reinforcing fibers and in the extrusion direction. And reduce the intensity difference in the other direction.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a composite sheet composed of a thermoplastic resin and reinforcing fibers.

2. Description of the Related Art As a method for obtaining a composite sheet composed of a thermoplastic resin and a reinforcing fiber, a method of kneading the reinforcing fiber and the thermoplastic resin and extruding as they are to form a sheet has been generally adopted. However, in the above method, since the reinforcing fibers are oriented in the extrusion direction, there is a drawback that the strength in the direction perpendicular to the extrusion is reduced.

In order to solve this drawback, for example, Japanese Patent Publication No. 60-54183 discloses that a composition comprising a thermoplastic resin and short glass fibers is melted and supplied to a mat in which long glass fibers are randomly arranged. -Protruded thermoplastic composite laminates have been proposed.

However, the above method requires a separate step of matting the reinforcing fibers, and when the amount of fibers increases, impregnation becomes difficult and a portion where no thermoplastic resin exists is formed between the filaments. There was a drawback that the strength of the composite varied.

[0004]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned drawbacks, and an object of the present invention is to provide a method for manufacturing a composite sheet having a small strength difference in the direction perpendicular to the extrusion direction.

The method for producing a composite sheet according to the present invention comprises the steps of melting a composition comprising a thermoplastic resin and reinforcing fibers, supplying the melted composition to a mold having distribution channels, and then merging at a discharge port, It is integrated and extruded.

Examples of the thermoplastic resin used in the composition comprising the thermoplastic resin and the reinforcing fiber include, for example, polyethylene, polypropylene, polyvinyl chloride,
Chlorinated polyvinyl chloride, polystyrene, polyamide, polyethylene terephthalate, polybutylene terephthalate, polycarbonate, polymethyl methacrylate, polyurethane, polyvinylidene fluoride, polyphenylene sulfide, polyphenylene oxide, polyether sulfone, polyether ether ketone, ethylene-
Vinyl chloride copolymer, vinyl acetate-ethylene copolymer,
Vinyl acetate-vinyl chloride copolymer, urethane-vinyl chloride copolymer, acrylonitrile-styrene copolymer, acrylonitrile-butadiene-styrene copolymer, acrylic acid modified polypropylene, maleic acid modified polyethylene, etc. It may be appropriately adopted depending on the situation. These may be used alone or in combination of two or more.

If necessary, the thermoplastic resin may include a lubricant,
Plasticizers, colorants, antioxidants, UV inhibitors, light stabilizers, inorganic fillers and the like may be added.

Examples of the reinforcing fiber include inorganic fiber such as glass fiber, carbon fiber and boron fiber; metal fiber such as stainless fiber and copper fiber; organic fiber such as aramid fiber, vinylon fiber and polyester fiber. These may be used alone or in combination of two or more.

If the length of the reinforcing fiber is too short, the reinforcing effect does not occur, and if it is too long, the fiber orientation is less likely to be disturbed at the time of merging, which will be described later, and the fiber is easily oriented in the extrusion direction. Is preferable, and more preferably 10 to 50 mm.

If the diameter of the reinforcing fiber is too small, the dispersibility will decrease, and if it is too large, the reinforcing effect will decrease.
0 μm is preferable.

If the content of the reinforcing fiber is too small, the reinforcing effect will not be produced, and if it is too large, the dispersion will be insufficient. Therefore, the content of the thermoplastic resin and the reinforcing fiber is 5 to 70 with respect to the total amount.
Weight percent is preferred.

In the production method of the present invention, the above composition is first melted by heating and supplied to a mold having distribution channels. If the heating temperature is too low, the composition does not flow, and if the heating temperature is too high, the thermoplastic resin deteriorates. Therefore, the heating temperature is not lower than the melting point of the thermoplastic resin.
Below the decomposition point is preferred.

If the viscosity of the melted composition is too high, the composition will not flow easily, and if it is too low, the orientation of the reinforcing fibers will be less likely to be disturbed at the time of merging, and the fibers will be easily oriented in the extrusion direction. , 400 to 1 × 10 ⁵ poise is preferable.

The distribution channel is a channel for dividing the molten composition into two or more. FIG. 1 is a sectional view showing an example of a mold having a distribution channel used in the present invention. 1 in the figure
Is an inlet, 2a and 2b are distribution channels, 3 is an outlet, and θ is a merging angle.

The distribution ratio of the composition of one flow path is preferably 30 to 70%, more preferably 30% to 70%, because the disorder of the orientation of the reinforcing fibers is less likely to occur at the time of merging, even if it is distributed too much or too little. Is the ratio of equal parts.

The distributed composition is merged, integrated and extruded at a discharge port formed by abutting distribution channels to obtain a composite sheet in which the orientation of reinforcing fibers is disturbed.

If the confluence angle θ of the distribution channel is too small, the orientation disorder of the reinforcing fibers is less likely to occur, and if it is too large, it becomes difficult to extrude the sheet. Therefore, it is preferably 45 ° to 180 °, more preferably 60 °. ~ 170 °.

Further, the shape of the distribution channel may be determined according to the width of the sheet to be extruded, for example, a columnar shape,
Examples thereof include a prismatic shape and a flat plate shape, but a sheet shape is particularly preferable.

If the width of the distribution channel is too small or too large, the reinforcing fibers are likely to be oriented at the time of merging.
It is preferably 1/2 to 2 times the width of the extruded sheet, and more preferably the same as the width of the sheet.

If the pressure of the composition at the time of merging is too small, the disorder of the orientation of the reinforcing fibers is less likely to occur, and if it is too large, the mold equipment is required to have an excessive strength, so that the pressure is 25 to 400 kg.
/ Cm ² is preferred.

[0020]

EXAMPLES The present invention will be described in more detail by way of examples.

Example 1 FIG. 2 is a schematic view showing an example of a method for manufacturing a composite sheet of the present invention. Hopper hole 5 of extruder 4 with 40 mm diameter
Homopolypropylene (manufactured by Mitsubishi Petrochemical Co., Ltd .; MA2A) was supplied as a thermoplastic resin, and was heated and melted at 205.

Further, chopped glass strands (length 13 mm, diameter 11 μm) are supplied from the vent hole 6,
A composition comprising a thermoplastic resin and glass fiber was obtained. The glass fiber content in the composition was 40% by weight.

Then, the molten composition was added to 70 kg / cm.
^It is supplied to a mold heated to 195 ° C at a pressure of ² and distributed by the manifolds 7a and 7b, with a thickness of 2 mm and a width of 400 m.
m and extruded from the discharge port by abutting at the distribution channels 2a and 2b having a merging angle of 160 ° to obtain a composite sheet 8 having a thickness of 3 mm and a width of 400 mm.

Example 2 Polyvinyl chloride as a thermoplastic resin (manufactured by Shin-Etsu Chemical Co .; T
K-800) and in the same manner as in Example 1 at 210 ° C.
It was melted by heating.

Further, chopped glass strands (length 13 mm, diameter 11 μm) are supplied from the vent hole 6,
A composition comprising a thermoplastic resin and glass fiber was obtained. The glass fiber content in the composition was 30% by weight.

Next, 100 kg / c of the molten composition is added.
It was supplied to a mold heated to 200 ° C. under a pressure of m ² , and a composite sheet having a thickness of 3 mm and a width of 400 mm was obtained in the same manner as in Example 1 below.

Comparative Example 1 Example 1 was repeated except that the mold having the distribution channel of Example 1 was replaced with the T die 9 having no distribution channel shown in FIG.
In the same manner as described above, a composite sheet having a thickness of 3 mm and a width of 400 mm was obtained.

COMPARATIVE EXAMPLE 2 The procedure of Example 2 was repeated except that a T die 9 having no distribution channel was used in place of the mold having the distribution channel of Example 2 and having a thickness of 3 mm and a width of 400 mm. A composite sheet was obtained.

Five test pieces each having a width of 20 mm and a length of 150 mm were cut out from each of the composite sheets obtained in Examples 1 and 2 and Comparative Examples 1 and 2 in the extrusion direction and the direction perpendicular thereto, and JIS K7203 was prepared. In accordance with this, a three-point bending test was performed with a fulcrum distance of 120 mm. The average values of bending strength and bending elastic modulus are shown in Table 1.

Similarly, from the extrusion direction and the right angle direction, the width 1
Table 1 shows the results of a Charpy impact test performed by cutting out five test pieces each having a length of 2.5 mm and a length of 90 mm.

[0031]

[Table 1]

[0032]

The method for producing the composite sheet of the present invention is as described above, and when the compositions distributed by the distribution channels join together, turbulent flow occurs, and the orientation of the reinforcing fibers in the extrusion direction is improved. Since it is disturbed, a composite sheet with a small difference in strength and flexural modulus between the extrusion direction and the direction perpendicular thereto can be obtained. For example, when this composite sheet is used as a stampable sheet, molding with uniform strength throughout is obtained. You can get the goods.

[0033]

[Brief description of drawings]

FIG. 1 is a sectional view showing an example of a mold having a distribution channel.

FIG. 2 is a schematic view showing an example of a method for producing a composite sheet of the present invention.

FIG. 3 is a schematic view showing a manufacturing method using a T die.

[Explanation of symbols]

 1 Inlet 2a, 2b Distribution flow path 3 Discharge port θ Merging angle 4 Extruder 5 Hopper hole 6 Vent hole 7a, 7b Manifold 8 Composite sheet 9 T die

Claims (1)

[Claims] 1. A composite sheet, comprising: melting a composition comprising a thermoplastic resin and a reinforcing fiber; feeding the composition to a mold having a distribution channel; Method.