JP2004114537A - Filament-reinforced thermoplastic resin molded article and method for manufacturing it - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To make continuous production possible by preventing a filament-containing molded body from clogging at a gate in hot runner molding, and to provide the molded body with a smooth surface. <P>SOLUTION: A filament-reinforced thermoplastic resin molded article is obtained by the hot runner molding from a material comprising a filament-reinforced thermoplastic resin pellet wherein reinforcing fibers are substantially arranged in parallel in the lengthwise direction of the pellet, and which is formed into a columnar, a prismatic or a tape-like shape, and is cut into a length of 3-14 mm, and its manufacturing is practiced. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a molded article obtained by molding a long fiber reinforced thermoplastic resin by hot runner molding and a method for producing the molded article.
[0002]
2. Description of the Related Art Hot runner molding is an injection molding method widely used from the viewpoint of shortening a molding cycle and reducing material loss.
[0003]
However, when injection molding long fiber reinforced thermoplastic resin pellets using a hot runner, the length of the fibers causes a bridging condition between the gate and the cavity, and the gate does not close tightly, resulting in a dirty gate after molding. Post-processing may be required. In the worst case, the unopened fiber mass may be clogged in the gate portion, and the opening and closing operation of the valve gate may not be possible, and the molding operation may have to be stopped. Therefore, molding by a hot runner method in molding a long fiber reinforced thermoplastic resin has not been practical.
[0004]
As proposed in the past, for example, Japanese Patent Application Laid-Open No. 8-142122 discloses a device for shortening the resin flow path.
[0005]
[Problems to be solved by the invention]
Accordingly, it is an object of the present invention to prevent a molded article containing long fibers from clogging a gate in a hot runner molding, to enable continuous production, and to obtain a molded article having a smooth surface.
[0006]
[Means for Solving the Problems]
As a result of intensive studies, the present inventor has found that in hot runner molding, gate clogging of a molded article containing long fibers is prevented, continuous production is enabled, and a molded article having a smooth surface is made possible.
[0007]
That is, in the present invention, the reinforcing fibers are arranged substantially parallel to the length direction of the pellet, shaped into a column, a prism or a tape, and cut into any length of 3 to 14 mm. Provided is a long-fiber-reinforced thermoplastic resin molded product obtained by hot runner molding from a material containing long-fiber-reinforced thermoplastic resin pellets.
[0008]
The present invention also provides a long-fiber-reinforced thermoplastic resin molded article, wherein the reinforcing fiber is any one of glass fiber, carbon fiber, aramid fiber, polyethylene naphthalate fiber, polyethylene terephthalate fiber and metal fiber.
[0009]
The present invention further provides a long-fiber-reinforced thermoplastic resin molded article by a molding method in which the above-mentioned hot runner includes a valve gate system.
[0010]
Further, in the present invention, the reinforcing fibers are arranged substantially parallel to the length direction of the pellet, shaped into a column, a prism or a tape, and cut into any length of 3 to 14 mm. To provide a method for producing a long-fiber-reinforced thermoplastic resin molded article obtained by hot runner molding from a material containing long-fiber-reinforced thermoplastic resin pellets.
[0011]
The present invention further provides a long-fiber reinforced thermoplastic resin molding, wherein the reinforcing fiber is any one of glass fiber, carbon fiber, aramid fiber, polyethylene naphthalate fiber, polyethylene terephthalate fiber and metal fiber. Provided is a method of manufacturing an article.
[0012]
The present invention also provides a method for producing a long-fiber-reinforced thermoplastic resin molded article in which the hot runner is a valve gate system.
[0013]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, the present invention will be described in detail. As the matrix resin of the long fiber reinforced thermoplastic resin pellets used in the present invention, any resin can be used as long as it is a thermoplastic resin. For example, general-purpose polystyrene, high-impact polystyrene, acrylonitrile-styrene copolymer resin, acrylonitrile-butadiene-styrene copolymer resin and other polystyrene resins, polyethylene, polypropylene and other polyolefin resins, polyethylene terephthalate, polybutylene terephthalate and the like Halogen-containing polyolefin resins such as thermoplastic polyester resins, polycarbonate resins, vinyl chloride and chlorinated polypropylene, and polyamides such as 6-nylon, 6,6-nylon, 4,6-nylon, 11-nylon, 12-nylon Resin, polyethyl acrylate resin, polyacrylic resin such as polymethyl methacrylate resin, polysulfonic acid resin, polyphenyl ether resin, polyacetal resin, liquid crystalline aromatic polyether Ether resin, polyphenylene sulfide resin, any thermoplastic resin and alloy resin composed of two or more of these general-purpose resins such as polyether ether ketone resin until super engineering plastics can be used. The resin forming the alloy is not limited to the thermoplastic resins listed here, and other well-known thermoplastic resins and two or more of these alloy resins can be used. Particularly preferred thermoplastic resins to which the present invention is applied include inexpensive polystyrene resins, polyolefin resins, and halogen-containing polyolefin resins.
[0014]
The reinforcing fibers of the long fiber reinforced thermoplastic resin pellets used in the present invention are not limited to the fibers listed below, as long as the fibers have a higher elastic modulus than the matrix resin to be used. Can also be used as reinforcing fibers. For example, glass fibers such as E-glass and D-glass; carbon fibers such as polyacrylonitrile, pitch, and rayon; inorganic fibers such as boron fiber and mineral fiber; metal fibers such as stainless steel and brass; ultra-high molecular weight polyethylene Fiber, polyoxymethylene fiber, polyvinyl alcohol fiber, liquid crystalline aromatic polyester fiber, polyethylene naphthalate fiber, polyethylene terephthalate fiber, aramid fiber such as poly-p-phenylene terephthalamide fiber, poly-m-phenylene isophthalamide fiber, poly Organic fibers such as acrylonitrile fiber, cellulose fiber such as cotton and jute and the like can be mentioned.
[0015]
Fibers to which the present invention is particularly preferable are glass fibers, carbon fibers, aramid fibers, polyethylene naphthalate fibers, polyethylene terephthalate fibers, and metal fibers.
[0016]
The reinforcing fibers are arranged substantially parallel to the length direction of the pellet, and the long fiber reinforced thermoplastic resin pellet shaped into a column, a prism, or a tape has a length of any of 3 to 14 mm. Although cut pieces can be used, they are preferably 3 to 9 mm, more preferably 5 to 9 mm. If it is shorter than 3 mm, it is difficult to cut the pellet, and if the reinforcing fiber is shorter than 3 mm, it is difficult to obtain strength as long fiber reinforcement. On the other hand, if it is longer than 14 mm, clogging at the valve gate increases, and continuous and stable production cannot be performed, and the smoothness of the surface of the molded product cut at the gate is impaired.
[0017]
The content of the reinforcing fibers contained in the long fiber reinforced thermoplastic resin pellets is not particularly limited, but is preferably 10 to 80% by mass based on the total of the resin pellets, and more preferably 20 to 70% by mass. %, Particularly preferably 30 to 60%.
[0018]
Furthermore, the content of the reinforcing fibers in the molded article varies depending on the required strength, but is preferably 1 to 50% by mass, more preferably 2 to 40% by mass based on the total amount of the molded article. And particularly preferably 5 to 30% by mass.
[0019]
The method for producing long fiber thermoplastic resin pellets is not particularly limited, but preferred examples include the following. This is a method of impregnating a molten thermoplastic resin while pulling out a roving of a fiber bundle. In order to uniformly impregnate the resin into the roving of the fiber bundle, the fiber bundle is preferably mechanically opened and impregnated with the resin, and the method of opening the fiber bundle is not particularly limited, Preferably, a crosshead die is used. Further, the drawn roving is cut into a desired length after cooling.
[0020]
The temperature of the resin to be molded in the hot runner molding is not particularly limited as long as it is equal to or higher than the melting temperature of the resin, but preferably, the melting temperature is + 150 ° C. from the melting temperature of the resin to be used. Preferably, the resin melting temperature is + 20 ° C to the resin melting temperature + 100 ° C. If the temperature is lower than the melting temperature of the resin, the flow of the resin is not smooth, and if the temperature is too high, scorching of the resin may occur.
[0021]
The heating method of the hot runner can be an internal heating method (torpedo type) or an external heating method (hot nozzle type). As the type of the gate, an open type such as a hot tip gate, a sprue gate, an edge gate and the like, and a valve gate of a spring type, a hydraulic type or a pneumatic type can be used.
[0022]
Also, in order to impart desired properties according to the purpose, known substances generally added to the thermoplastic resin, for example, antioxidants, heat stabilizers, stabilizers such as ultraviolet absorbers, antistatic agents, flame retardants, It is also possible to add a flame retardant aid, a coloring agent such as a dye or a pigment, a lubricant, a plasticizer, a crystallization accelerator, a nucleating agent, and the like. Further, plate-like or powdery inorganic compounds such as glass flakes, mica, glass powder, glass beads, talc, clay, alumina, carbon black, wollastonite, etc., and whiskers may be used in combination.
[0023]
【The invention's effect】
In the injection molding by hot runner molding, the reinforcing fibers are arranged substantially parallel to the length direction of the pellet, shaped into a column, a prism or a tape, and cut into an appropriate length. By using long fiber reinforced thermoplastic resin pellets, stable production has become possible, and furthermore, it has become possible to improve the smoothness of the injection cut surface of the molded product.
[0024]
【Example】
Hereinafter, the present invention will be described in detail with reference to examples, but the present invention is not limited to the examples.
[0025]
Example 1
200 parts by mass of stainless steel fiber reinforced ABS resin pellets (Plastron ABS-SF40 L = 6; manufactured by Daicel Chemical Industries) containing 40% by mass of stainless steel fibers cut to a length of 6 mm and arranged substantially in parallel, and ABS resin (Sebian 680) A material mixed with 800 parts by mass of Daicel Chemical Industries) into an injection molding machine hopper, and injection molding using a valve gate hot runner system (manufactured by Seiki Co., Ltd.) having a gate diameter of 3 mm and two gates. Continuous molding was performed. Molding machine cylinder temperature 230 ° C (hot runner manifold temperature 230 ° C). Even if 100 moldings were performed, it was possible to manufacture stably without clogging at the gate. The smoothness of the injection cut surface (gate portion) of the molded product was also good.
[0026]
Example 2
Example 1 except that the length of a stainless steel fiber reinforced ABS resin pellet containing 40% by weight of stainless steel fiber was cut to 9 mm, and that 800 parts by weight of ABS resin was used for 200 parts by weight of fiber reinforced ABS resin pellet. This was performed in the same manner as in Example 1. As a result, a good result equivalent to that of Example 1 was obtained.
[0027]
Example 3
500 parts by mass of aramid fiber reinforced polypropylene resin pellets containing 30% by mass of aramid fibers (KEVLAR29 manufactured by Du Pont-Toray Co., Ltd.) cut to a length of 6 mm and arranged substantially in parallel, and a polypropylene resin (Noblen W501; manufactured by Sumitomo Chemical Co., Ltd.) Use 500 parts by mass of mixed materials. Injection molding was performed in the same manner as in Example 1. Even if 100 moldings were performed, it was possible to manufacture stably without clogging at the gate. The smoothness of the injection cut surface of the molded product was also good.
[0028]
Comparative Example 1
The same operation as in Example 1 was performed except that stainless steel fiber reinforced ABS resin pellets containing 40% by mass of stainless steel fibers and cut to a length of 15 mm were used. When 20 compacts were manufactured, the fibers were entangled in the valve gate, the operation was stopped, and cleaning was performed. In addition, many scratches were observed on the injection cut surface of the twentieth molded body.

Claims (6)

The reinforcing fibers are arranged substantially parallel to the length direction of the pellet, shaped into a column, a prism, or a tape, and cut into any length of 3 to 14 mm. A long fiber reinforced thermoplastic resin molded product obtained by hot runner molding from a material containing thermoplastic resin pellets. The long fiber reinforced thermoplastic resin molded product according to claim 1, wherein the reinforcing fiber is any one of glass fiber, carbon fiber, aramid fiber, polyethylene naphthalate fiber, polyethylene terephthalate fiber, and metal fiber. 3. The long fiber reinforced thermoplastic resin molded product according to claim 1, wherein the hot runner is a valve gate system. The reinforcing fibers are arranged substantially parallel to the length direction of the pellet, shaped into a column, a prism or a tape, and cut into any length of 3 to 14 mm. A method for producing a long-fiber-reinforced thermoplastic resin molded article obtained by hot runner molding from a material containing thermoplastic resin pellets. The long fiber reinforced thermoplastic resin molded product according to claim 4, wherein the reinforcing fiber is any one of glass fiber, carbon fiber, aramid fiber, polyethylene naphthalate fiber, polyethylene terephthalate fiber and metal fiber. Production method. The method for producing a long fiber reinforced thermoplastic resin molded product according to claim 4 or 5, wherein the hot runner is a valve gate system.