JPH06126814A - Molding method for plastic hollow structural member - Google Patents

Abstract

PURPOSE:To obtain a molded product reinforced by a long fiber member, by performing blow molding without breaking a long-sized fiber during a molding process. CONSTITUTION:Laminating plastic materials, 510, 520 become parison 511, 522 by being extruded through a die 56 passing through passages A, C. A long fiber member 530 passes through the die 56 from the passage B provided separately from the passages A, C from an upstream of the die 56. The long fiber member 530 is premolded in the course of passing through the die 56 and enters a mold 55 by being put between the parison 511, 522. The same is blow-molded by a mold 55 part and a hollow structural member is formed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for blow molding a hollow structure made of a plastic material reinforced with fibers having a long fiber size.

[0002]

2. Description of the Related Art In recent years, the problem of global warming caused by carbon dioxide has been widely taken up, and reduction of environmental pollution and energy saving have been screaming. Therefore, in automobiles, along with the improvement of the engine and the like, there is an increasing demand for weight reduction of the vehicle body to improve the fuel efficiency of the vehicle. A plastic material is suitable as a material to reduce the weight of the vehicle body and is already used for instrument panels, trim covers, etc., but plastic materials are also used for bodies, chassis, frames, etc. Is being attempted. However, in order to use plastic members for these parts, the material needs to be lightweight and rigid. Therefore, in order to satisfy both the weight saving and the rigidity of the plastic material,
A structure in which a plastic material is filled with a glass mat to reinforce and the shape of the product is hollow is adopted. Blow molding and gas injection molding are possible methods for forming hollow structure products. In both methods, long fibers (from 3 mm to 5 mm) are used as a reinforcing material to fill the parison.
(0 mm) or a thermoplastic material such as a glass mat which is a continuous fiber cannot be used, and a hollow structure product having high rigidity cannot be manufactured.

For example, a method of molding a hollow plastic material reinforced with a fiber material is disclosed in Japanese Patent Publication No. 62-5777 and Japanese Patent Publication No. 62-32023. As shown in FIG. 4, a method for manufacturing a polyolefin hollow-molded article described in Japanese Patent Publication No. 62-5777 discloses that fibers (the length of the fiber is 0.05 mm) before blow molding.
30 mm) and a polyolefin material are mixed, and the mixture is fed from the screw into the extrusion die 3 by the extruders 1 and 2. Then, the respective resin materials are fusion-bonded in a multi-layered manner at the joining portion 4 in the co-extrusion die 3 and co-extruded as a multi-layered parison 6 from the die face 5 at the tip thereof. This is a method in which the multi-layered parison 6 is held by a mold 7 and pressurized air is blown into the parison 6 to form a hollow product corresponding to the cavity 9 of the multi-layered mold.

Further, as shown in FIG. 5, the method for manufacturing a composite hollow skin body disclosed in Japanese Patent Laid-Open No. 62-32023 discloses a pair of half mold halves that match the outer shape of a predetermined hollow skin body. The parison 13 extruded from the extrusion die 12 between 11 hangs down in a suspended manner. Further, in a state in which a cloth 15 knitted or woven using a mixed yarn or crimped yarn of polyester, nylon, acrylic or the like is heated by a heater 14,
While pulling out between the mold 11 and the parison 13, the parison 13
A synthetic resin film-shaped hot melt material 16 is suspended between the cloth 15 and the cloth 15. Then, the mold 11 is heated to fuse the hot melt material 16 to the cloth 15 and the parison 13 at the time of molding, and compressed air is forced into the parison 13 from the nozzle 17 to expand the parison 13 to the outside, and the cavity 11 And the fabric are co-pressed on the cavity wall of the mold 11 to obtain a hollow product reinforced with the fabric.

[0005]

However, in the method for manufacturing a polyolefin molded hollow molded article described in Japanese Patent Publication No. 62-5777, fibers and a synthetic resin are mixed before blow molding and then molded. Since the fibers are put into the screw part of the machine, fibers having a certain length (for example, a fiber length of 30 mm or more) are cut by the screw to become short-sized fibers. A molded product containing fibers could not be obtained. Further, in the method for producing a composite hollow skin body described in JP-A-62-32023, a hot melt material is used to adhere a cloth for reinforcement to a parison, and the cloth or hot melt is used. As a means for heating the material, an infrared heater, an ultrasonic wave, an electric heat heater, etc. are required, and as a molding device, it becomes a device with a large number of parts, and in order to bond the parison and the cloth. Required a hot melt material.

Therefore, the present invention provides a molding method which solves the above-mentioned inconvenience and enables a plastic hollow structure reinforced with long-sized fibers to be formed with a simple structure.

[0007]

According to the method for molding a plastic hollow structural member of the present invention, a first plastic material made of a thermoplastic resin is extruded from an extrusion die to form a first parison, and at the same time a thermoplastic first material is formed. The second plastic material is extruded through an extrusion die to form a second parison. Further, a long fiber member having a long fiber dimension is passed through the die part through a route different from the forming route of the first parison and the second parison, and the first parison and the second parison are preliminarily preformed. A hollow structure member is formed by being sandwiched and blown up.

[0008]

Since the long fiber member sandwiched between the first parison and the second parison passes through a route different from the route through which the first plastic material and the second plastic material pass through the extrusion die. The long-sized fiber is preformed by the heat of the die in the long-sized state without being agitated by the screw of the extruder. The preformed long fiber member is easily blown up.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The details of the present invention will be described with reference to the drawings. FIG. 1 shows a main part of a molding apparatus for carrying out the present invention. The first plastic material 510 is supplied to the first material supply section 51 of the blow molding device, and the first plastic material 51 is supplied.
0 is pushed by an extruding means such as a screw of an extruder (not shown), and is extruded from the lower part of the die 56 through the passage A. Then, the mold 55 is used as the first parison 511.
Droop inside. A passage B is arranged outside the passage A arranged in the die 56. In the passage B, two mat-shaped members 530, which are long fiber members formed by continuously matting long-sized fibers (for example, a fiber length of 3 mm to 50 mm) are supplied at the same speed as the first plastic material 510, and It is sent into the mold 55.
A passage C communicating with the second material supply unit 52 is arranged outside the passage B. The second plastic material 520 is supplied from the second material supply unit 52. The second plastic material 520 is pushed by an extruding means such as a screw of an extruder (not shown), and is extruded from the lower portion of the die 56 through the passage C provided on the outer periphery of the passage B, so that the first parison 5
A second parison 522 is hung on the outer periphery of 11 through a mat-shaped member 530 into the mold 55. The feeding speeds of the second plastic material 520, the first plastic material 510, and the mat-shaped member 530 are the same.

The first parison 511, the second parison 522, and the mat-shaped member 530 that hang down inside the cavity 57 of the mold 55 are air blowing nozzles 58 that are open at the top.
Is expanded by the compressed air blown into the first parison 511 and is pressed against the wall surface of the cavity 57 of the heated mold 55. The first parison 511, the second parison 522, and the mat-shaped member 530 are firmly fused and integrally joined by the heat of the mold 55. Then, the mold 55 is cooled to form a hollow molded product.

Here, the resin used as the first plastic material 510 and the second plastic material 520 is a synthetic resin having thermoplasticity (for example, polypropylene,
Polyethylene, styrene resin, vinyl chloride resin, polycarbonate, saturated polyester, polyamide, etc.) are used. Normally, the first parison 511 and the second parison 522 use the same plastic material in order to improve the fusion efficiency. However, when the appearance is specially adjusted or the weather resistance is improved, a resin with a good surface treatment or a colored resin is used for the second parison, which is the surface of the product, or chloride with excellent weather resistance is used. Use vinyl resin.

As the mat member 530, a long glass fiber such as a random glass mat, a carbon mat, or an aramid mat is continuously formed into a mat.
When the mat-shaped long fibers are not well compatible with the resin material of the first parison and the second parison, the first parison 511 and the second parison 522 are previously provided on the mat-shaped member 530.
The resin which is easy to adjust to is coated or the mat member 530 is preheated.

In the apparatus for carrying out the molding method of the present invention, the flat mat-shaped member 530 is located upstream of the die 56 or at the die 56, and is different from the passage A through which the first plastic material 510 passes. Sent to the molding process. As shown in FIG. 2, the mat-shaped member 530 in the portion shown by the arrow in FIG. 1 which is upstream of the die 56 is a long plate member having a straight plate in the cross-sectional shape. And passage B
While passing through the inside, the plate-shaped mat member 530 is gradually narrowed into a circular shape at the taper portion above the die 56. Die 5
The mat-shaped member 530 that has passed through the passage B inside 6 is molded by the heat of the die 56 and becomes a curved long plate body having a substantially semicircular cross section as shown in FIG. In this way, the mat-like member 53 temporarily formed into a semicircular cross section is formed.
0 is also the first parison 511 having an elliptical cross section,
The mold 55 is sandwiched between the second parison 522.
Droop in. At this time, the mat-shaped member 530 temporarily formed on the way through the die 56 reaches the inside of the die 55.
Since the first parison 511 and the second parison 522, which are curved with substantially the same curvature, cure at the same speed, they rarely come into contact with each parison 511522.

As described above, according to the molding method of the present invention, only the plastic materials 511 and 522 are charged from the extruder for extruding the resin material by the screw, and the mat-like member 530 formed of long-sized fibers has the screw. Since the fibrous member does not pass through the working stirring portion, the fibrous member is not mechanically broken by the rotation of the screw, and the hollow structural member formed by the molding method of the present invention has the first fibrous member in the state of long-sized fibers. Between the second parison and the parison of
It has rigidity reinforced with long dimension fibers. In addition, since the mat-shaped member 530 is preformed into a substantially semicircular shape by the heat of the die 56, it is easy to expand during the molding of the die 55,
Blow molding can be easily performed in the state of long-sized fibers.

[0015]

According to the conventional method, long-sized fibers are cut by a screw, but the molding method of the present invention has high reinforcing efficiency for reinforcing hollow structural members, and long-length fibers. Since it is fed into the mold without passing through the screw of the extruder, it is molded as long-sized fibers as it is,
Be commercialized. Furthermore, since the long fiber member having a long mat-like shape is previously formed into a curved shape that substantially matches the cross-sectional shape of the parison by the heat of the die, it is easy for the mold to blow up. Further, since the traveling speed of each parison to the mold and the traveling speed of the fiber member are the same, and the curved shape of the long fiber member sandwiched between each parison and the parison is almost the same, the curved shape Prior to (blow) molding, the matt filaments reduce contact with parallel parison surfaces, improving the accuracy of the molded part. Further, the molding apparatus adopting the molding method of the present invention does not require a special means for heating the fiber member, and does not need a member for bonding the fiber member for reinforcement to each parison. The molding method of the present invention does not require special heating means or adhesion means, and can easily blow and mold reinforcing fibers having a long fiber length in a state of a long dimension, and the molding method of the present invention In the hollow structural member, since long fibers are present in the member in a long state, the hollow structural member has a high reinforcing effect and satisfies the requirements of rigidity and light weight.

[Brief description of drawings]

FIG. 1 is an explanatory view of a main part of a blow molding machine to which the present invention is applied.

FIG. 2 is a cross-sectional view of the mat-shaped member taken along the arrow X in FIG.

FIG. 3 is a cross-sectional view of the mat-shaped member taken along the arrow Y in FIG.

FIG. 4 is an explanatory view of a conventional blow molding machine.

FIG. 5 is an explanatory view of another conventional blow molding machine.

[Explanation of symbols]

 51 1st plastic material supply part 52 2nd plastic material supply part 55 Mold 56 Die 510 1st plastic material 511 1st parison 520 2nd plastic material 522 2nd parison 530 Mat member

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Eiichi Nakagawa, Eizo Nakagawa, Fujisawa-shi, Kanagawa 8 Isuna Central Research Institute Co., Ltd. (72) Inventor, Masayuki Somura 8-story, Fujisawa, Kanagawa Isuzu Central Research Co., Ltd. In-house (72) Nobuo Yagi No. 8 Tsutana, Fujisawa City, Kanagawa Prefecture Isuzu Central Research Institute Co., Ltd. (72) Inventor Tokuroro Yamashita No. 8 Tsutana, Fujisawa City, Kanagawa Prefecture Isuzu Central Research Institute Co., Ltd.

Claims (2)

[Claims] 1. A step of supplying a first plastic material made of a thermoplastic resin to an extrusion die, and a long fiber member having a long fiber size is supplied to the extrusion die from the outer periphery of the supply portion of the first plastic material, A step in which the long fiber member is heated by the heat of the die to be preformed, and a second step made of a thermoplastic resin
The step of supplying the plastic material from the outer periphery of the supply part of the long fiber member to the extrusion die, and the first plastic material and the second plastic material being extruded from the extrusion die to form the preformed long fiber member. Through a step of forming a second parison on the outer periphery of the first parison, and a forming step of expanding the long fiber member while sandwiching the long fiber member between the first parison and the second parison. The first plastic material feeding portion to the die, the long fiber member feeding portion to the die, and the second plastic material feeding portion to the die are independent of each other, and the long fiber A method for molding a plastic hollow structural member, wherein the member is supplied from the upstream of the extrusion die at the same speed as the extrusion speed of the first parison and the second parison. 2. The method for molding a plastic hollow structural member according to claim 1, wherein the long fiber member is a mat-shaped member in which long-sized fibers are randomly stacked.