JPH07314441A - Heat extrusion method and apparatus - Google Patents

Abstract

(57) [Summary] [Object] To provide an air mixing method and apparatus capable of heating and extruding a mixture without cutting the reinforcing fibers and supplying the mixture to a molding step. [Structure] A tubular body having a discharge port on one end side and a storage section for storing a mixture of reinforcing fibers and powdery thermoplastic resin on the other end side, and one end of the tubular body A casing having a throttle part that converges toward the discharge port,
A plunger that is arranged at the other end of the casing and is movable toward the throttle, a compression supply unit that compresses the mixture in the storage unit and supplies the mixture to the extrusion side of the plunger, and a heating unit that heats the mixture in the casing. And are provided.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heating extrusion method and an apparatus for heating and extruding a mixture obtained by mixing a reinforcing fiber and a powdery thermoplastic resin for molding a fiber reinforced plastic molded article. is there.

[0002]

2. Description of the Related Art Conventionally, when a final product shape is molded from a composite material in which reinforcing fibers are uniformly dispersed in a powdery resin, for example, a block-shaped preform is manufactured as a preceding step. ing. In order to obtain the preform, first, the reinforcing fiber and the powdered resin are mixed to obtain a mixed material. As an example of a mixing method, an air mixing method is known in which these are mixed in an air stream formed by a jet gas (see, for example, JP-A-63-135550).

Then, in order to obtain a final product shape from the preform, the preform is heated and filled in a mold, and compression molding is performed. Therefore, in order to simplify the manufacturing process consisting of multiple steps, it is possible to directly supply the composite material obtained by air mixing to the molding process for obtaining the final product shape without manufacturing a preform. Various hot extrusion methods have been investigated.

[0004]

However, when the above-mentioned composite material is melted and extruded under pressure using an extruder used for general extrusion molding, a reinforcing fiber is produced by a screw rotating in a heating cylinder. Has not been put to practical use, because the problem that the molded product obtained is cut and the strength of the obtained molded article decreases.

The present invention has been made in consideration of the above-mentioned problems of the conventional heat extrusion method, and the heat extrusion capable of heat extruding the mixture without cutting the reinforcing fiber and supplying it to the molding step. It is an object to provide a method and an apparatus thereof.

[0006]

According to the present invention, a mixture of reinforcing fibers and a powdered thermoplastic resin is compressed and supplied to the extrusion side of a plunger arranged in a cylindrical casing, and the plunger is discharged to the discharge side. This is a heating and extrusion method in which the mixture is pressed and melted by pressing it toward the formed narrowed portion and heating it.

The present invention comprises a tubular body having a discharge port on one end side and a storage section for storing a mixture of reinforcing fibers and powdery thermoplastic resin on the other end side. A casing having a throttle portion that converges toward the discharge port near one end, a plunger that is arranged at the other end in the casing and that can move toward the throttle portion, and a plunger that compresses the mixture in the storage portion. The heating and extruding device is provided with a compression supply means for supplying the mixture to the extruding side and a heating means for heating the mixture in the casing.

In the above-mentioned heating and extruding apparatus, as an example of the heating means, there is a heating means constituted by an external heating heater attached to the outer wall of the casing and an internal heating heater inserted inside the casing. Further, it is preferable that the internal heater has a streamlined shape along the axial direction of the casing and reduces the flow path in the casing to pressurize the mixture.

Further, a metering extrusion device can be further connected to the discharge port of the heating extrusion device. Further, the preformed body in the present invention refers to those in which reinforcing fibers are dispersed in a thermoplastic resin to form a lump, and the thermoplastic resin to be mixed in producing the preformed body is polypropylene or the like. General-purpose resin, nylon, PET
Engineering plastics such as, and the reinforcing fibers include organic fibers such as glass fibers, carbon fibers and aramid fibers.

[0010]

In the present invention, the mixture of the reinforcing fiber having a low bulk specific gravity and the powdery thermoplastic resin is compressed and supplied to the pushing side of the plunger arranged in the tubular casing, and the tubular casing is discharged. The plunger presses the mixture towards the squeeze formed on the side to heat it under pressure, thereby acting to heat extrude the mixture without cutting the reinforcing fibers.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail below with reference to the embodiments shown in the drawings. FIG. 1 shows an embodiment of an apparatus used in the heat extrusion method of the present invention. In the figure,
MA is an air mixing device, and DM is a characteristic part of the present invention, and is a heating extrusion device connected to the downstream side of the air mixing device MA.

First, the air mixing apparatus MA will be described. The air mixing apparatus MA comprises a roving cutter 1 for quantitatively supplying a reinforcing fiber bundle cut into a predetermined length and a screw feeder for quantitatively supplying a powdery thermoplastic resin. 2, an air mixer 3 which is composed of a spirally wound tube body and generates a turbulent air flow when compressed air is introduced, an outlet of the roving cutter 1, an outlet of the screw feeder 2, and an inlet of the air mixer 3. And a storage tank 5 connected to the outlet of the air mixer 3, and a fixed amount of the reinforcing fiber bundle and the powdered resin are pneumatically transported to the air mixer 3 via the ventilation passage 4, The reinforcing fiber bundle is opened in the air mixer 3, mixed with the powdery thermoplastic resin, and the resulting mixture is sent to the storage tank 5. And a Nozuru 6.

The roving cutter 1 aligns the glass fiber strands unwound from the roving 1a and cuts them into a predetermined length. By controlling the rotational speed of the cutter, the reinforcing fiber bundle is supplied in a fixed amount. You can do it. The screw feeder 2 has a charging port 2a for charging the powdered resin and a screw 2c for transferring the charged powdered resin to the discharge port 2b side by a thrusting action, and controls the rotation speed of the screw 2c. By doing so, the powdered resin can be supplied in a fixed amount.

The air mixer 3 is composed of a tubular body wound in a substantially rectangular shape when viewed from the spiral axis direction (direction of arrow A in the figure), and turbulent air flow in the air mixer 3 due to collision of compressed air at each corner thereof. Is to occur. The air passage 4 is made of a tubular member, and an air nozzle 7 is arranged in the air passage 4 downstream of the discharge port 2b of the screw feeder 2. When compressed air is introduced from the air nozzle 7, a suction force is exerted on the upstream side thereof, and the powdery thermoplastic resin and the reinforcing fiber bundle, which are supplied in a fixed amount, are sucked into the air mixer 3.

The storage tank 5 is composed of a cylindrical container with a bottom, and a pusher 5a that reciprocates in the vertical direction (direction of arrow B in the figure) in the container, a hydraulic or pneumatic cylinder 5b for driving the pusher 5a, and a container. A discharge pipe 5c extending horizontally from the body, a shutter 5d that opens and closes the discharge port of the discharge pipe 5c, a discharge pipe 5c arranged at the inner bottom of the storage tank 5 and rotating in the discharge pipe 5c, in the direction of arrow C. The screw 5e that generates the thrust of the motor and the motor 5f that rotationally drives the screw 5e are provided. In the figure, 5g is a filter provided on the intake side. 5h is an air discharge pipe, which is connected to a dust collector (not shown).

The mixture discharged from the shutter 5d of the storage tank 5 is then supplied to the heating extrusion device DM. The heating extrusion device DM has a discharge port 7a on one side.
And a cylindrical casing 7 for heating and melting the mixture supplied from the hopper 7b, which is provided with a hopper (reservoir) 7b for storing the mixture of the reinforcing fiber and the powdery thermoplastic resin on the other side. A narrowed portion 7c which is formed at one end of the casing 7 and focuses toward the discharge port 7a,
A plunger 8 which is arranged at the other end of the casing 7 and presses the mixture in the casing 7 toward the narrowed portion 7c.
A pusher 9 (compression supply means) for compressing the mixture in the hopper 7b and supplying it to the extrusion side of the plunger 8, and an external heater 10 and an internal heater 11 as heating means for heating the mixture in the casing 7. It is mainly composed of A metering and extruding device 13 is connected to the discharge port 7a via a molten raw material supply valve 12.

The hopper 7b is a bottomed cylindrical container extending upward from the body of the casing 7, and the pusher 9 can move up and down (in the direction of arrow D in the figure). The pusher 9 is driven by a pneumatic or hydraulic cylinder 9a, and stands by at the position of the top plate of the bottomed cylindrical container when not operating. The casing 7 is
The large-diameter portion 7 is for forming a passage for accommodating the mixture supplied from the hopper 7a and sending it forward (in the direction of arrow E).
d, the narrowed portion 7c, the small diameter portion 7e, the nozzle portion 7f, and the connector 7g, and the external heater 10 is attached to the outer body portion extending from the large diameter portion 7d to the connector 7g. The external heater 10 can be composed of, for example, a band heater or a block heater whose temperature can be controlled. In addition, temperature control is not limited to heating with a heater,
It is preferable that cooling can also be performed.

Inside the large-diameter portion 7d, both ends are formed in a substantially conical shape to form a streamlined tubular internal heater 11.
Are inserted along the axial direction of the casing 7. The internal heater 11 is for uniformly heating the mixture, and has a gear-shaped cross-sectional shape as shown in the sectional view taken along the line FF of FIG. To increase the heating efficiency. Therefore, as the mixture passes through the gap G, the external heater 10
And both sides of the internal heater 11 are heated. In addition,
Gas is enclosed in the tube of the internal heater 11, and the enclosed gas is heated by the electric heater 11a. Since the reinforcing fiber itself acts as a heat insulating material, it is difficult to uniformly heat the inside of the mixture in a short time only by external heating. However, by providing the external heater 10 and the internal heater 11 having the above-described configurations, it becomes possible to heat the inside of the mixture in a short time.

The plunger 8 can reciprocate in the direction of the arrow E in the casing 7 up to the front of the internal heater 11 by the pneumatic or hydraulic cylinder 8a. When the plunger 8 is not operating, the plunger 8 stands by behind the hopper 7b. There is.
The metering and extruding device 13 includes a tubular member 13b having a focusing nozzle portion 13a at its tip, a plunger 13c that reciprocates in the tubular member 13b in the direction of arrow H, a cylinder 13d that drives the plunger 13c, and an arrow I. It is composed of a cutter 14 that moves in the direction to open and close the focusing nozzle portion 13a, and an external heater 15 attached to the outer wall of the tubular member.

The operation of the present embodiment having such a configuration will be described below separately for mixing and heating extrusion. It is assumed that the shutter 5d is closed at the start of the mixing operation. First, roving cutter 1
In, the glass fiber strands unwound from the roving 1 a are cut into a predetermined length, and the cut reinforcing fiber bundle is quantitatively supplied to the air passage 4. On the other hand, in the screw feeder 2, the powdered resin charged from the charging port 2a is quantitatively supplied to the ventilation path 4. In this way the ventilation path 4
The reinforcing fiber bundle and the powdery resin sent to the air mixer 3 are respectively sent into the air mixer 3 by the suction action of the compressed air jetted from the air nozzle 6, and the air mixer 3
The turbulent airflow generated therein opens the reinforcing fibers and then mixes them uniformly with the powdered resin.

The mixture obtained after passing through the air mixer 3 is stored in the storage tank 5. Here, when the shutter 5d is opened to discharge the mixture, the mixture having a low bulk specific gravity, which is filled in the storage tank 5, is compressed toward the screw 5e by the pusher 5a descending. Then, when the screw 5e is rotated, the feeding action causes the compressed mixture to be fed in the direction of the arrow C and is discharged from the discharge port. However, while the shutter 5d is opened and the mixture is being discharged, the injection of compressed air from the air nozzle 6 is stopped to interrupt the air mixing.

The mixture thus obtained is sent to the heating extruder DM. The molten raw material supply valve 1
2 is assumed to be closed. The mixture put into the hopper 7b is compressed by the pusher 9 descending and supplied to the extrusion side of the plunger 8 (the pusher 9 is at the position indicated by the chain double-dashed line in the figure). Then, when the plunger 8 is pushed forward (the plunger 8 is at the position indicated by the chain double-dashed line in the figure), the mixture passes through the gap G along the wall surface of the internal heater 11 and is heated and melted. Next, the melted mixture is introduced into the narrowed portion 7c to be pressurized, and is further uniformly heated in the small diameter portion 7e. Then, when the raw material supply valve 12 is opened, the molten mixture is sent to the metering and extruding device 13. The discharge port of the metering and extruding device 13 is assumed to be closed by the cutter 14.

In the metering and extruding device 13, the plunger 13c is provided.
The molten mixture is extruded to the discharge port side by moving the forward direction, and the extruded molten mixture is collected by the focusing nozzle portion 13a.
The pressure is increased to a high density, and the cutter 14 is opened for a predetermined period to measure and discharge the molten mixture. By performing such an operation, continuous heat extrusion can be performed.

In the above embodiment, the glass fibers are cut and supplied in a fixed amount, but the invention is not limited to this.
Alternatively, the pre-cut glass fibers may be weighed and quantitatively supplied. Further, the control operation described above can be implemented by software by a microcomputer, or can be implemented by hardware by a sequence control circuit that performs the same function.

[0025]

As is apparent from the above description, according to the present invention, the mixture can be heated and extruded without cutting the reinforcing fiber and supplied to the molding step. Also,
The heat extrusion can be carried out continuously. Since the heating and melting section is composed of a narrow passage heated from the outside and the inside, the mixture can be heated and melted in a short time.

In the structure in which the metering extruder is connected, the mixture stays in the casing and the tubular member for a long time, and uniform heating can be obtained.

[Brief description of drawings]

FIG. 1 is a configuration diagram of an apparatus used in a heating extrusion method of the present invention.

FIG. 2 is an F showing a cross-sectional shape of the internal heater shown in FIG.
It is a -F arrow sectional view.

[Explanation of symbols]

 MA air mixing device DM heating extrusion device 1 roving cutter 1a roving 2 screw feeder 3 air mixer 4 air passage 5 storage tank 6 air nozzle 7 casing 7a discharge port 7b hopper 7c throttle part 8 plunger 9 pusher 10 external heating heater 11 internal heating heater 12 Raw material supply valve 13 Measuring extruder

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification number Reference number within the agency FI Technical display location B29K 105: 08 (72) Inventor Takao Yumoto 1-5-5 Takatsukadai, Nishi-ku, Kobe-shi, Hyogo Kobe Steel Co., Ltd.Kobe Research Institute

Claims (5)

[Claims] 1. A mixture of reinforcing fibers and a powdered thermoplastic resin is compressed and supplied to an extruding side of a plunger arranged in a cylindrical casing, and the plunger is directed to a throttle portion formed on a discharge side. A heating and extruding method, wherein the mixture is pressed and melted by pressing and heating. 2. A tubular body having a discharge port on one end side and a storage section on the other end side for storing a mixture of a reinforcing fiber and a powdery thermoplastic resin. A casing having a throttle portion that converges toward the discharge port near one end portion, a plunger that is disposed at the other end portion inside the casing and that can move toward the throttle portion, and the mixture inside the storage portion. A compression supply means for compressing and supplying the mixture to the extrusion side of the plunger; and a heating means for heating the mixture in the casing,
A heat-extruding device comprising: 3. The heating / extruding apparatus according to claim 2, wherein the heating means comprises an external heater attached to the outer wall of the casing and an internal heater inserted inside the casing. 4. The heating and extruding device according to claim 3, wherein the internal heater has a streamlined shape along the axial direction of the casing and reduces the flow path in the casing to pressurize the mixture. 5. The heating extrusion device according to claim 2, wherein a metering extrusion device is further connected to the discharge port.