JPH08142122A - Injection machine for fiber reinforced thermoplastic resin - Google Patents

Abstract

PURPOSE: To provide a molding machine of fiber reinforced thermoplastic resin capable of preventing damage of fiber in the flow of molten resin and the occurrence of waste resin, and also conducing the cut removing work readily in the conjunction part with a resin passage part at the time of making into articles. CONSTITUTION: This machine includes an injection cylinder 7 for injecting fluidized fiber reinforced thermoplastic resin into a mold, a resin passage 6 having one end communicated to the inner part of the injection cylinder 7 and the other end communicated to the opening of the cavity 3 of the mold, and a gate cutter (interruption material) 10 for interrupting the resin passage 6, wherein the resin passage 6 is made large in its diameter and short in its length, and also reduced in the number of curved parts, and the gate cutter 10 is provided near the opening 4 of the cavity 3.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a molding machine for a thermoplastic resin material reinforced with fibers such as glass, and in particular, it is reinforced with fibers such as glass having a relatively long length (about 3 mm to 25.4 mm). The present invention relates to a molding machine for the thermoplastic resin material.

[0002]

2. Description of the Related Art In order to improve the strength of a resin molding machine, it has been conventionally practiced to mix fibers such as glass for reinforcement, and a thermoplastic resin is used to facilitate molding using this resin. , Fiber-reinforced thermoplastic resins mixed with fibers have been used for reinforcement, and are mainly used for injection molding of automobiles, home appliances, OA parts, civil engineering, and building material parts. There is.

On the other hand, in most conventional resin injection molding machines, the nozzle hole at the tip of the injection cylinder is 4 to 6 mm, and in a normal case, sprue, runner, The diameter of the gate is also small. In addition, these flow path structures in the mold have become complicated and long in recent years, and this tendency is particularly remarkable in a mold for multi-cavity molding in which a large number of molds are simultaneously molded. In addition, since the waste of sprue and runner material is eliminated, the flow path of this resin becomes even longer when using a hot runner.

As described above, when an attempt is made to mold a thermoplastic resin containing fibers such as glass by using an ordinary injection molding machine or the like in which the molten resin passes through a narrow and long passage, a thin portion or a curved portion of the passage is formed. Also, the fibers are broken during the flow in the long passage portion and become short fibers. In the fiber reinforced resin, the longer the mixed fiber length, the greater the strength.
Even if the fibers mixed in the molten resin are long, if the fibers are broken during molding as described above, the strength of the molded resin will not be sufficiently high.

[0005]

In the above-mentioned various conventional apparatuses, in which the molten resin passes through a narrow and long passage, and also through a passage with many bends, particularly long fibers are mixed. The resin has poor fluidity,
Not only is proper molding not performed, but when passing through these passages, internal long fibers are gradually broken, and when they are molded, they become short fibers, and the product does not have a predetermined strength. Further, when the pressure is increased to improve the fluidity of the resin in the passage, the breakage of the fiber is also promoted.

On the other hand, in order to prevent breakage of the fibers during the flow of the resin, it may be possible to increase the diameter of the flow passage. However, if the diameter of the flow passage is simply increased, a large amount of resin is wasted when cooled after molding. Not only does this occur, but since the gate of the product has a large diameter, it not only takes time and time to cut it, but also this cut edge after it becomes a product becomes conspicuous, and it may be necessary to perform subsequent processing. is there.

Therefore, the present invention prevents the breakage of the fibers when the molten resin flows and prevents the generation of useless resin, and the work of cutting and removing the connection portion with the resin passage portion at the time of commercialization is performed. An object of the present invention is to provide a molding machine for a fiber-reinforced thermoplastic resin, which is easy.

[0008]

In order to achieve the above object, a molding machine for a fiber reinforced thermoplastic resin according to the present invention comprises an injection cylinder for injecting a fluidized fiber reinforced thermoplastic resin into a mold and an end. Is provided with a resin passage communicating with the inside of the injection cylinder and the other end communicating with the opening of the cavity of the mold, and a blocking member for blocking the resin passage, and the resin passage has a large diameter and is short,
In addition, the number of bends is reduced and the blocking member is provided near the opening of the cavity.

In the above-mentioned molding machine for the fiber reinforced thermoplastic resin, the blocking member may be a gate cutter which advances and retracts in the transverse direction of the resin passage to block it, or
It may be a gate block provided with a pressing means for pressing the resin on the opening side of the cavity. Furthermore, the blocking member may be made of a heat insulating material.

[0010]

Since the present invention is configured as described above, when the fluidized fiber-reinforced thermoplastic resin is injected from the injection cylinder through the resin passage into the cavity of the mold, the resin passage has a large diameter. Since the fiber is short and has few bends, the fiber is less likely to be broken and the long fiber is injected into the cavity of the mold as it is. After injection, the opening of the cavity and the resin passage are blocked by the blocking member. At this time, since the blocking member is provided close to the opening of the cavity, the post-processing work of the molded product is reduced.

[0011]

Embodiments of the present invention will be described with reference to the drawings. FIG. 1 shows a first embodiment of the present invention, in which a cavity 3 is formed between a fixed mold 1 and a movable mold 2 above the fixed mold 1, and an opening 4 provided in the center of the lower portion of the fixed mold 1 will be described later. When a predetermined amount of the fiber reinforced thermoplastic resin is introduced into the and the opening 4 is closed, and then the movable mold 2 is lowered by the operation of the movable plate 5,
The introduced resin is compressed to flow and diffuse to the peripheral portion, and a product having a predetermined shape can be molded.

The opening 4 of the cavity 3 is fixed to the fixing plate 9 provided below the fixed mold 1 through the resin passage 6 in the fixed mold 1.
It is communicated with the nozzle portion 8 at the tip of the injection cylinder 7 which is fixed to. A gate cutter (blocking member) provided in the resin passage 6 in the vicinity of the opening 4 so that the opening 4 can be opened and closed.
A heater 11 is provided around the resin passage 6 between the gate cutter 10 and the nozzle portion 8.

The gate cutter 10 is actuated by the working cylinder 12, moves in the transverse direction through the resin passage 6 in a portion as close as possible to the opening 4, and after a predetermined amount of resin is injected into the cavity 3, the gate cutter 10 is moved. The opening 4 is closed by the operation so that the resin inside does not flow backward when the movable mold 2 moves.

The resin passage 6 is formed from the nozzle portion 8 to the opening 4 of the cavity 3 sufficiently thicker than that of an ordinary injection molding machine, and is so short as not to form a bent portion at all. I am configuring. Along with that, the nozzle portion 8 also has the same diameter as the resin passage 6 and has a larger diameter.

A well-known plunger type is adopted as the injection cylinder 7, and the molten resin introduced into the cylinder chamber 13 has a nozzle portion 8 and resin when the plunger 14 moves upward by the operation of a hydraulic cylinder (not shown). It is injected into the cavity 3 through the passage 6 and the opening 4. The outer periphery of the injection cylinder 7 is heated by the heater 15, and the nozzle portion 8
The outer circumference of is also heated by the heater 16.

The injection cylinder 7 is provided with a supply port 17 opening to the cylinder chamber 13, and the supply port 17 has a plasticizing device 18 therein.
The thermoplastic resin mixed with the plasticized fiber is supplied. Various devices can be adopted as the plasticizing device 18, but in the embodiment shown in FIG. 1, the hopper 20 is used.
The pellets of the thermoplastic resin mixed with the long fibers introduced in, are guided to the opening 23 of the cylinder 22 having the screw 21 inside, and the screw 21 is rotated by an external drive device,
Send to the exit 24 side. At this time, the outer circumference of the cylinder 22 is heated by the heater 25.
The heating fluid is introduced from the outside through the rotary joint 26 into the hole in the screw 21 to be heated, and the resin in the cylinder 22 is heated by the heat generated by the shearing of the resin when the screw 21 rotates. It is melted and plasticized.

In the above apparatus, the long fiber reinforced thermoplastic resin melted and plasticized by the plasticizer 18 is used in the injection cylinder 7
When a predetermined amount is supplied to the cylinder chamber 13 of the above, the movable mold 2 moves upward, and the gate cutter 10 is opened with the cavity 3 having a sufficient space formed, and the plunger 14 is moved upward, the cylinder chamber 13 A predetermined amount of the molten resin therein is injected into the cavity 3 through the nozzle portion 8 and the resin passage 6.

At this time, the long fiber reinforced thermoplastic resin injected from the nozzle portion 8 into the cavity 3 is mixed in the resin because all the passages are formed to have a large diameter, the passages are short and there is no bending portion. The long fibers such as the glass fibers that are used can minimize breakage.

Next, the gate cutter 10 is closed, and the movable mold 2
Is lowered and the resin in the cavity 3 is pressed to spread it over the entire cavity 3 to form a predetermined shape. After the resin is cooled, the molded product is taken out of the mold, and the resin portion remaining between the opening 4 and the gate cutter 10 is shaved to obtain a product. At this time, since the residual resin is extremely small, the removal work may be unnecessary. Even if the removal work is performed, the removal work can be performed easily and in a short time. Also,
Since the resin passage 6 is short, a small amount of resin remains in this passage portion after the molding operation is completed, and waste resin can be reduced.

In the above embodiment, the example in which the injection cylinder 7 is arranged facing upward is shown, but as shown in FIG. 2, the injection cylinder 7, the fixed mold 1 and the movable mold 2 are arranged sideways. Is also good. In the figure, the plasticizer 30
Employs a material that is heated and melted by being pressed between heating belts 31 and 32 arranged so as to face each other, whereby pellets containing long fibers are mixed so that the axis of the longitudinal direction thereof is the plane of the belt. Since the fibers are pressed and melted in a substantially parallel state, breakage of the long fibers can be minimized. The resin melted in the plasticizing device 30 is pushed into the cylinder chamber 13 of the injection cylinder 7 by the rotation of the screw 33, and thereafter, the resin is molded by the same operation and action as in the above embodiment.

In each of the above embodiments, the gate cutter
As 10, the flat plate is moved in the direction traversing the resin passage 6,
Although the example of blocking the opening 4 and the resin passage 6 is shown, the gate block 35 may be used as a blocking member as shown in FIG. That is, in this apparatus, the nozzle portion 8 of the injection cylinder 7 is fitted and fixed in the lower mold 36, and the lower mold 36 and the upper mold 36 are fixed.
A cavity 38 is formed between 37. This cavity
At the center of 38, the resin passage 40 communicating with the nozzle portion 8
Communicates with the opening 41 of the cavity 38, and the gate block 35 is slidably provided in the upper mold 37 so as to face the opening 41.

The gate block 35 is a pressing hydraulic cylinder 42.
When the gate block 35 is retracted, the cavity is opened between the opening 41 and the gate 41 as shown in the figure.
It forms part of 38. However, the cavity 38
After the injection of the predetermined resin into the inside, the gate block 35 is moved to the opening 41 side by the operation of the hydraulic cylinder 42, and the resin on the front surface is pushed toward the nozzle 8 side and the cavity 38 for the molded product to open the opening 41. Close. At this time, the side surface of the gate block 35 constitutes the side wall of the remaining product cavity 38. After cooling the resin in the cavity 38, the upper mold 37 is removed and the molded product is taken out. In this molding machine, the cavity 38 can be formed in a donut shape with the gate block 35 as a central hole, or can be a multi-cavity molding machine in which upper and lower cavities 38 in the drawing are different products. it can.

In the figure, an example in which a deep groove twin-screw kneader is used as the plasticizing device 43 is shown, and the cylinder and screw thereof are heated as in the device of FIG. Although the resin is melted by this, various devices can be used without being limited to such a plasticizing device.

In the embodiment shown in FIG. 3, when the gate block 35 as a blocking member closes the opening 41, the gate block 35 is pushed into the cavity 38 forming the resin product on the front surface thereof. In the above, by pushing the resin, it is possible to prevent sink marks during cooling of the molded product. Further, in this method, since the gate portion of the so-called mold is removed by the gate block 35 during molding, it is possible to provide a gate having a sufficiently large diameter and a large thickness without fear of wasting material. This is effective for preventing breakage of the fibers while the resin is passing through the gate portion. This molding means can also be adopted in the injection compression process.

When the gate cutter 10 shown in FIGS. 1 and 2 is made of a heat insulating material such as ceramic, the heat insulating material is interposed between the resin passage side which is always heated and kept warm and the mold to be cooled. Thus, mutual heat conduction can be prevented, and a molding machine with good operating efficiency can be provided, and cooling and solidification of the resin material at the spool, the gate portion, etc. can be prevented.

[0026]

EFFECTS OF THE INVENTION Since the present invention is constructed and operates as described above, it is possible to prevent breakage of the fibers mixed in the resin and prevent the generation of useless resin. The work of cutting and removing the connection portion with the resin passage portion at the time of liquefaction becomes easy.

Further, in the case where the blocking member is provided with the pressing means for pushing the resin to the opening side of the cavity, it is possible to prevent the sink in the cavity when the resin is cooled.

Further, in the case where the blocking member is formed of a heat insulating material, a heat insulating layer is formed between the resin passage portion which is always heated and kept warm and the mold portion which is cooled, and heat loss due to heat conduction between both portions is caused. Can be reduced.

[Brief description of drawings]

FIG. 1 is a sectional view of an embodiment of the present invention.

FIG. 2 is a sectional view of another embodiment of the present invention.

FIG. 3 is a sectional view of still another embodiment of the present invention.

[Explanation of symbols]

1: Fixed mold 2: Movable mold
3: Cavity 4: Opening 5: Movable platen
6: Resin passage 7: Injection cylinder 8: Nozzle part
9: Fixed board 10: Gate cutter 11: Heater 1
2: Working cylinder 13: Cylinder chamber 14: Plunger 1
5, 16: Heater 17: Supply port 18: Plasticizer 2
0: Hopper 21: Screw 22: Cylinder 2
3: Opening 24: Exit 25: Heater 2
6: Rotary joint 30: Plasticizer 35: Gate block 3
6: Lower mold 37: Upper mold 38: Cavity 4
0: Resin passage 41: Opening 42: Pressing hydraulic cylinder 4
3: Plasticizer

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Akira Asari 2-3-3 Niihama, Arai-cho, Takasago-shi, Hyogo Kobe Steel Works Takasago Works

Claims (4)

[Claims] 1. An injection cylinder for injecting a fluidized fiber-reinforced thermoplastic resin into a mold, a resin passage having one end communicating with the inside of the injection cylinder and the other end communicating with an opening of a cavity of the mold, and the resin. Molding of fiber reinforced thermoplastic resin, characterized in that it has a blocking member for blocking the passage, the resin passage has a large diameter and is short, the number of bends is small, and the blocking member is provided close to the opening of the cavity. Machine. 2. The molding machine for fiber reinforced thermoplastic resin according to claim 1, wherein the blocking member is a gate cutter that moves forward and backward in the resin passage in a transverse direction to block the resin passage. 3. The gate block, wherein the blocking member is provided with a pressing means for pressing the resin toward the opening side of the cavity.
A molding machine for the fiber-reinforced thermoplastic resin described. 4. The molding machine for fiber reinforced thermoplastic resin according to claim 1, wherein the blocking member is made of a heat insulating material.