JP2002307430A - Method for manufacture of fiber-reinforced resin molding material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for manufacture of fiber-reinforced resin molding material wherein generation of a damage of reinforcing fiber is little, though organic fiber is used as the reinforcing fiber, generation of heat deterioration is little and application to a short fiber is also easy. SOLUTION: A resin composition comprising thermoplastic resin and reinforcing fiber is fed to a clearance between an inner peripheral surface of a die ring 3 and a press roll 4 of a granulator 1 wherein a cylindrical die ring 3 having many through holes 31 the press roll 4 which confronts an inner peripheral surface of the die ring 3 beyond a very small clearance and is made freely rotatable, and a cutting edge 5 which confronts an outer peripheral surface of the die ring 3 across a very small clearance are provided. By rotating the die ring 3 under conditions wherein though the thermal plastic resin is melted, the reinforcing fiber is not melted, the press roll 4 is rotated while the resin composition is melted and kneaded. The kneaded resin composition is discharged from the through hole 31 of the die ring 3 to the outer peripheral side of the die ring 3 and the resin composition discharged from the through hole 31 is cut with the cutting edge 5.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for producing a fiber-reinforced resin molding material.

[0002]

2. Description of the Related Art In order to improve the heat resistance and mechanical strength of a thermoplastic resin, an inorganic fiber has been conventionally added. In order to improve impact resistance, it has been proposed to further add an organic fiber.

[0003] The addition of such reinforcing fibers is carried out by kneading the mixture by heating and stirring with a mixer. Melt and knead with a roll, extruder, co-kneader, etc. Etc., and further pelletized to obtain a molding material.

However, in these methods, since the thermoplastic resin and the reinforcing fiber are mechanically kneaded for a long time, there is a problem that the reinforcing fiber is broken and the characteristics of the reinforcing fiber cannot be fully utilized. When an organic fiber is used as a reinforcing fiber, the organic fiber exposed to a high temperature for a long time causes thermal deterioration, and there is a problem that sufficient impact resistance cannot be obtained.

[0005]

Therefore, in producing organic fiber reinforced resin pellets containing organic fibers by a melt drawing method, the organic fibers are immersed in a molten polyolefin resin bath and the immersion time is reduced to 6 seconds. There has been proposed a method of producing organic fiber reinforced resin pellets in which the resin-impregnated organic fibers are drawn out of the resin bath in a time not exceeding the time (Japanese Patent No. 3073988).

However, in the above-mentioned production method, the organic fibers must be continuous fibers, and it is difficult to apply the organic fibers to short fibers.

[0007] The present invention solves the above-mentioned problems, and hardly causes breakage of the reinforcing fiber. Even if an organic fiber is used as the reinforcing fiber, it hardly causes thermal deterioration, and is easily applied to short fibers. An object of the present invention is to provide a method for producing a fiber-reinforced resin molding material.

[0008]

According to the present invention, there is provided a method for producing a fiber-reinforced resin molding material, comprising: forming a resin composition comprising a thermoplastic resin and reinforcing fibers into a cylindrical die ring having a large number of through holes; Molding material production provided with a press roll rotatably facing the inner peripheral surface of the die ring with a minute gap therebetween and a cutting blade facing the outer peripheral surface of the die ring with a minute gap therebetween. The resin is supplied to the gap between the inner peripheral surface of the die ring and the press roll of the device, and the thermoplastic resin is melted, but the reinforcing fiber is melted and kneaded by rotating the die ring under the condition that the fiber is not melted. While rotating the press roll, the kneaded resin composition is discharged from the through hole of the die ring to the outer peripheral side of the die ring, and the resin composition discharged from the through hole is cut by the cutting blade. Than it is.

[0009] The thermoplastic resin used in the present invention is not particularly limited.
Olefin resins such as polypropylene; vinyl chloride resins; styrene resins such as polystyrene, acrylic-modified polystyrene, acrylonitrile- (ethylene-propylene-diene) -styrene copolymer, acrylonitrile-butadiene-styrene copolymer; acrylic resins; Thermoplastic polyesters such as polyethylene terephthalate; polycarbonates; These may be used alone or in combination of two or more.

The reinforcing fiber used in the present invention is not particularly limited, and examples thereof include inorganic fibers such as carbon fiber, glass fiber, metal fiber, and alumina fiber; aramid fiber, polyester fiber, nylon fiber, vinylon fiber,
Organic synthetic fibers such as acrylic fiber and rayon fiber, wood flour,
Cellulose organic fibers such as cotton and hemp; natural organic fibers such as wool and silk; These may be used alone or in combination of two or more.

The above inorganic fibers are added to suppress thermal expansion and contraction, improve mechanical strength such as rigidity, and improve heat resistance such as an increase in heat deformation temperature. The effect is small, and if it is too large, the fluidity of the obtained resin composition is remarkably reduced and the moldability is deteriorated. Therefore, the amount is preferably 2 to 40 parts by weight based on 100 parts by weight of the thermoplastic resin.

The above organic fibers are added for the purpose of improving impact resistance and the like. If the amount of the organic fibers is too small, the above-mentioned effects are small, and if the amount is too large, dispersion in the thermoplastic resin becomes difficult. Therefore, the amount is preferably 5 to 50 parts by weight based on 100 parts by weight of the thermoplastic resin.

The fiber shape of the organic fiber is not particularly limited as long as it can be put into a granulator, such as chop, roving, milled fiber, and cotton.

[0014]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a side view showing an example of a granulator used in the method for producing a fiber-reinforced resin molding material of the present invention.

In FIG. 1, 1 is a granulator, 3 is a die ring, 4 is a press roll, and 5 is a cutting blade.

As shown in FIG. 1, a granulator 1 used in the manufacturing method of the present invention has a hopper 2, a cylindrical die ring 3, and a small gap between the inner peripheral surface of the die ring 3 and the hopper 2. A press roll 4 that faces and is rotatable, and a cutting blade 5 that faces the outer peripheral surface of the die ring 3 with a small gap therebetween.

FIG. 2 is an enlarged perspective view showing the die ring. As shown in FIG. 2, a large number of through holes 31 are provided in the die ring 3.

The method for producing a fiber-reinforced resin molding material of the present invention comprises the steps of:
First, it is supplied from the hopper 2 of the granulator 1 shown in FIG. Next, the resin composition is melted and kneaded by rotating the die ring 3 under the condition that the thermoplastic resin is melted but the reinforcing fiber is not melted by a motor (not shown). The supplied resin composition rotates the press roll 4 by the frictional force, and is kneaded by the rotation. Then, the kneaded resin composition solidifies and is discharged from the through hole 31 of the die ring 3 shown in FIG. The resin composition discharged from the through hole 31 is cut by the cutting blade 5 shown in FIG. 1 to form a pellet of a desired size.

[0019]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail based on embodiments.

(Example) Acrylic-modified polystyrene (manufactured by A & M Co., Ltd.) was placed in a hopper 2 of a granulator 1 shown in FIGS.
Part number "SM050") 100 parts by weight, carbon fiber chop (manufactured by Toho Rayon Co., Ltd., trade name "Pesfight HTA-C"
6-SR "; average fiber diameter 7 μm, average fiber length 6 mm)
8 parts by weight and 12 parts by weight of a polyester fiber chop (trade name “SOLUNA B250” manufactured by Mitsubishi Rayon Co., Ltd.) are put in, and the thickness 25 having many through holes 31 with a diameter of 4 mm
mm of the die ring 3 and the press roll 4.

Then, by rotating the die ring 3 at a rotation speed of 200 rpm by a motor, the acryl-modified polystyrene was melted, and the carbon fiber and the polyester fiber were kneaded without melting to obtain a resin composition. The obtained resin composition is solidified and the through-holes 31 are formed.
From the die ring 3 and cut by the cutting blade 5 to obtain a pellet having a diameter of 4 mm and a length of 10 mm.

The obtained pellets were supplied to an extruder (Model "TEX44", manufactured by Nippon Steel Corporation) to obtain a plate-like molded body having a width of 100 mm and a thickness of 5 mm.

Comparative Example 1 Kneading was carried out in the same manner as in the example except that the diameter of the through hole 31 of the die ring 3 was 6 mm and the thickness of the die ring 3 was 60 mm, but the acrylic-modified polystyrene was not melted. No pellet was obtained.

(Comparative Example 2) Kneading was carried out in the same manner as in Example except that the diameter of the through hole 31 of the die ring 3 was 4 mm and the thickness of the die ring 3 was 45 mm. Not only acrylic-modified polystyrene but also carbon fibers and polyester fibers were melted and kneaded. Hereinafter, pellets were obtained in the same manner as in the examples, and plate-like molded bodies were produced in the same manner as in the examples.

Comparative Example 3 A single-screw kneading extruder (Model “UT- 2
5 ”), kneaded, and a pelletizer (manufactured by Takeno Iron Works, model“ TAN-S-5 ”) having a diameter of 4 mm and a length of 10 mm.
mm pellets were obtained. Using the obtained pellets, a plate-like molded body was obtained in the same manner as in the example.

The plate-like molded articles obtained in Examples and Comparative Examples 2 and 3 were subjected to the following evaluations. Linear Expansion Coefficient of Physical Properties In accordance with JIS K7197, the linear expansion coefficient at 30 to 80 ° C was measured.

Izod impact strength Izod impact strength was measured according to JIS K7110.

Tensile modulus According to ASTM D638, the tensile modulus was measured. The above results are summarized in Table 1.

[0029]

[Table 1]

[0030]

According to the method for producing a fiber-reinforced resin molding material of the present invention, a resin composition comprising a thermoplastic resin and a reinforcing fiber is prepared by forming a cylindrical die ring having a large number of through holes, and The die of a granulator provided with a press roll that is rotatably opposed to the outer peripheral surface with a minute gap therebetween and a cutting blade that is opposed to the outer peripheral surface of the die ring with a minute gap therebetween. The press roll is supplied to the gap between the inner peripheral surface of the ring and the press roll, while the thermoplastic resin is melted, but the reinforcing fiber is melted and kneaded by rotating the die ring under a condition that does not melt. Rotate
The kneaded resin composition is discharged from the through hole of the die ring to the outer peripheral side of the die ring, and the resin composition discharged from the through hole is cut by the cutting blade. This is less likely to occur, and even if organic fibers are used as the reinforcing fibers, thermal degradation is less likely to occur, and application to short fibers is easy.

[Brief description of the drawings]

FIG. 1 is a side view showing an example of a granulator used in a method for producing a fiber-reinforced resin molding material of the present invention.

FIG. 2 is an enlarged perspective view showing the die ring of FIG. 1;

[Explanation of symbols]

 Reference Signs List 1 granulator 3 die ring 31 through hole 4 press roll 5 cutting blade

Claims (1)

[Claims] 1. A resin composition comprising a thermoplastic resin and a reinforcing fiber is opposed to a cylindrical die ring having a large number of through-holes and separated by a small gap from an inner peripheral surface of the die ring, and rotated. The gap between the inner peripheral surface of the die ring and the press roll of a granulator provided with a freely press roll and a cutting blade facing the outer peripheral surface of the die ring with a minute gap therebetween And the thermoplastic resin melts,
By rotating the die ring under the condition that the reinforcing fiber is not melted, the press roll is rotated while melting and kneading the resin composition, and the kneaded resin composition is discharged from the through hole of the die ring to the outer peripheral side of the die ring. Let me
A method for producing a fiber-reinforced resin molding material, comprising cutting the resin composition discharged from the through hole with the cutting blade.