JPH05329839A - Fiber reinforced theremoplastic resin structure and production thereof - Google Patents

Abstract

PURPOSE:To efficiently and economically produce a fiber reinforced thermoplastic resin structure having high mechanical strength reinforced by a long fiber and markedly improved in the dispersibility of a reinforcing fiber. CONSTITUTION:The continuous reinforcing fiber bundle taken out of a reinforcing fiber bundle aggregate is impregnated with a molten thermoplastic resin while pulled to produce a fiber reinforced thermoplastic resin structure containing substantially parallelly arranged reinforcing fibers in an amount of 5-800% by wt. of the whole of the structure. In this method, the reinforcing fiber bundle to be used is obtained by forming a fiber bundle composed of fibers subjected to sizing treatment into a cylindrical wound body and drying the same so as not to substantially generate the evaporation from the upper and lower side surface parts of the wound body.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a fiber-reinforced thermoplastic resin structure which is reinforced with long fibers and has a high degree of mechanical strength, and in which the dispersibility of reinforcing fibers is remarkably improved, and its efficient and economical structure. Manufacturing method.

[0002]

2. Description of the Related Art As a means for improving the strength and rigidity of a thermoplastic resin, it has been known to incorporate a reinforcing fiber such as glass fiber, and generally, a thermoplastic resin is used. Fiber-reinforced thermoplastic resin is manufactured by mixing and short fibers such as chopped strands and extruding with an extruder. However, the short fiber reinforced resin as described above, in which the fiber used is short, and the fiber is further broken during kneading in an extruder, is naturally limited in improving the mechanical strength. It cannot fully meet the demand for mechanical strength. On the other hand, pultrusion has recently attracted attention as a method for improving the above-mentioned drawbacks and producing a thermoplastic resin reinforced with long fibers without causing breakage of the fibers (US Pat. No. 2,877,501). U.S. Pat.No. 4,439,387, U.S. Pat.No. 3,022,210, JP-A-57-1818.
No. 52). In such pultrusion molding, as a reinforcing fiber, a large number of single fibers pulled out from a bushing are treated with an aqueous solution or an aqueous emulsion of a sizing agent, and then bundled and wound into a cylindrical shape to dry. So-called direct roll roving packages have been commonly used. However, when such a commercially available reinforcing fiber is usually used to produce a fiber-reinforced resin structure by the above-mentioned pultrusion method, impregnation of the resin with respect to the fiber and adhesion are likely to be non-uniform, and Fibers are easily disentangled and scattered from the obtained fiber reinforced resin structure, which not only impairs the working environment and impairs moldability, but also causes a lack of uniform dispersion of reinforcing fibers when molded. It has the drawback of impairing the appearance and physical properties of the molded product. In addition, when taking out the fiber bundle from the fiber bundle assembly or when pulling the fiber bundle under tension, fluffing occurs due to partial breakage of the fiber, impairing operability, and operation becomes impossible due to increased fuzzing. There is also.

[0003]

Means for Solving the Problems As a result of intensive studies for solving the above problems, the present inventor has shown that the resin has good impregnation property and adhesion between the resin and the fiber, and has high mechanical strength and fiber. In order to efficiently obtain a fiber-reinforced thermoplastic resin structure whose dispersibility and the like have been remarkably improved,
The present inventors have found that it is extremely effective to use a reinforcing fiber bundle in which the amount of the sizing agent attached to the reinforcing fibers locally varies, and have reached the present invention. That is, the present invention relates to a fiber-reinforced thermoplastic resin which comprises a continuous reinforcing fiber bundle, is impregnated with a molten thermoplastic resin, and contains 5 to 80% by weight of the total reinforcing fibers arranged substantially in parallel. In producing the resin structure, as a reinforcing fiber bundle, the sizing-treated and bundled fiber bundle is formed into a cylindrical or cylindrical-like wound body, and vaporization from both upper and lower side surface portions, in other words, both end surface portions substantially occurs. A method for producing a fiber-reinforced thermoplastic resin structure characterized by using a reinforcing fiber bundle obtained by drying so as not to exist, and a fiber-reinforced thermoplastic resin structure obtained by such a production method. is there.

In the present invention, the kind of the thermoplastic resin used as the substrate of the fiber reinforced thermoplastic resin structure is not particularly limited, and examples thereof include polyethylene, polypropylene, polyesters such as polyethylene terephthalate and polybutylene terephthalate, nylon 6, and the like. Polyamide such as nylon 66, nylon 11, nylon 12, nylon 610, nylon 612, polyacetal, polycarbonate, thermoplastic polyurethane, polyphenylene oxide, polyphenylene sulfide, polysulfone, polyetherketone, polyetheramide, and polyetherimide. .

Next, the reinforcing fiber used in the present invention will be described. Conventionally, in pultrusion molding, a large number of fiber filaments pulled out from a bushing are treated with an aqueous solution or an aqueous emulsion of a sizing agent, and then bundled and wound into a cylindrical shape to dry a bundle of fibers,
Commercially available packages have been used as so-called direct roving packages. However, according to the studies conducted by the present inventors, the roving package thus obtained has a sizing agent that is not uniformly distributed over the entire reinforcing fiber bundle because the sizing agent causes migration during drying. The variation in the amount of sizing agent locally applied is extremely large, and especially the amount of sizing agent applied is particularly high on the upper and lower side surfaces of the wound roving package, that is, both end surfaces, near the outer circumference and the inner circumference of the cylinder. It was found that the concentration was reached. Further, the present inventors have found that such a large variation in the amount of the sizing agent attached causes various problems in the pultrusion molding,
That is, the impregnation of the resin is poor, the adhesion between the resin and the fiber is poor, and the fibers are easily loosened and scattered from the reinforced resin structure obtained with it, which is the root cause of damaging the working environment and impairing the molding processability. Further, it was clarified that it is a cause of poor dispersion of reinforcing fibers when such a reinforced resin structure is molded. The present invention has been made on the basis of such findings, as a reinforcing fiber, a sizing-treated and bundled fiber bundle, for example, roving, sliver, yarn into a cylindrical or cylindrical-like wound body, It is characterized by using a reinforcing fiber bundle obtained by drying without vaporization from the side surface portion substantially. The fiber bundle thus obtained has little local variation in the sizing agent, which remarkably improves the above problems. A method of drying the sizing-processed and bundled fiber bundle into a cylindrical or cylindrical-like wound body and then drying without substantially vaporizing from the upper and lower side surfaces is substantially gas-free. A method in which a permeable substance, for example, a film or the like, is dried in a state of being in close contact can be mentioned. As described above, in the case of direct roving which is a cylindrical wound body, the sizing agent causes migration due to normal drying, that is, the amount of sizing agent adhered to the fiber bundle locally at the upper and lower side surfaces of the cylinder, in other words, at both end surfaces. Although it causes extremely high concentration and causes various problems, sizing is performed by sizing and bundling the bundle of fibers into a cylindrical or cylindrical-like wound body and drying it so that vaporization from the upper and lower side surfaces does not substantially occur. The local variation in the amount of agent adhered is small, and good results are obtained. Even in this case, the sizing agent is likely to be concentrated in the vicinity of the inner peripheral surface and the outer peripheral surface of the wound body due to migration of the sizing agent at the time of drying, but since the local variation is relatively small, there is no problem in operability. Few. Further, it is extremely easy to remove only the fiber bundle in this portion, and it is more effective to remove it in advance and use it, or leave it unused and use the roving in the effective portion. As a result, a fiber-reinforced resin structure having good dispersibility of the reinforcing fibers can be obtained. The type of sizing agent used to bundle the reinforcing fibers is not particularly limited, for example, olefin-based,
Any sizing agent such as urethane type, polyester type, acrylic type, AS resin type and epoxy type can be used. The appropriate amount of the sizing agent applied to the fiber is about 0.1 to 1.0% by weight as a solid content. Further, the type of reinforcing fiber used is not particularly limited, and for example, glass fiber, carbon fiber, metal fiber, high melting point (high softening point) fiber such as aromatic polyamide fiber and the like can be used. In the case of glass fiber, a fiber bundle having a fiber diameter of 6 to 25 .mu. And a weight per 1000 m of 500 to 4400 g is generally used. These fibers may be treated with a known surface treatment agent.

In the present invention, the compounding amount of such reinforcing fibers is 5 to 80% by weight of the whole. If the content of the reinforcing fibers is less than 5% by weight, a sufficient reinforcing effect cannot be obtained, while if it exceeds 80% by weight, the production of the reinforced structure and its molding become extremely difficult. The preferred amount of the reinforcing fiber is 10 to 75% by weight, more preferably 20 to 70% by weight.

A pultrusion method is used to manufacture the long fiber reinforced thermoplastic resin structure of the present invention. Pultrusion molding is basically impregnating a resin while pulling continuous fibers. The form of pultrusion molding used for producing the long fiber reinforced thermoplastic resin structure of the present invention is not particularly limited, but it is preferable to use an impregnation die, particularly a crosshead die, from the viewpoint of operability.

[0008]

The present invention will be described in more detail with reference to the following examples, but the present invention is not limited thereto. Example 1 A glass fiber bundle that has been treated with an emulsion containing a sizing agent and is in a wet state is wound into a direct roll, and a sheet that is impermeable to water and water vapor is adhered to the upper and lower side surfaces, that is, both ends, and the glass fiber is dried. A bundle was obtained. While pulling the glass fiber bundle taken out from this roll through a crosshead, it was impregnated with molten polypropylene, shaped, and shredded to obtain a glass content.
A pellet-like fiber-reinforced resin structure (A) was obtained at 50% by weight. Next, the glass content was diluted to 15% by weight by blending the pellet-shaped fiber-reinforced resin structure (A) with pellets of non-reinforced polypropylene, and injection molding was performed to obtain a 100 mm square flat plate molded product. The evaluation was performed by the operability during the production of the fiber-reinforced resin structure (A) and the dispersibility of the reinforcing fibers in the flat plate molded article. The results are shown in Table 1.
Incidentally, the evaluation of dispersibility is a relative evaluation in consideration of the degree and number of the unevenly dispersed portions of the reinforcing fiber in the molded product while being bundled, and the lower the score, the higher the dispersibility. Indicates good.

Comparative Example 1 A fiber-reinforced resin structure was produced, molded and evaluated in the same manner as in Example 1 by using a glass fiber bundle wound in a direct roll and dried by an ordinary method. The results are also shown in Table 1.

[0010]

As is apparent from the above description and examples, in producing a long-fiber-reinforced thermoplastic resin structure, a reinforced fiber bundle is sized and bundled into a cylindrical or cylinder-like shape. According to the method of the present invention using the reinforcing fiber bundle obtained by drying the wound body so that vaporization from the upper and lower side surfaces does not substantially occur, the operability during production is excellent, and A fiber-reinforced thermoplastic resin structure having extremely good dispersibility of reinforcing fibers during molding can be obtained.

[0011]

[Table 1]

Claims (3)

[Claims] 1. A fiber-reinforced thermoplastic comprising a continuous reinforcing fiber bundle, impregnated with a molten thermoplastic resin, and containing 5 to 80% by weight of the total reinforcing fibers arranged substantially parallel to each other. When manufacturing a resin structure, as a reinforcing fiber bundle, the sizing-treated and bundled fiber bundle is made into a cylindrical or cylindrical-like wound body, and dried so that vaporization from the upper and lower side surfaces does not substantially occur. A method for producing a fiber-reinforced thermoplastic resin structure, comprising using the reinforcing fiber bundle obtained by the above. 2. The method for producing a fiber-reinforced thermoplastic resin structure according to claim 1, wherein the molten thermoplastic resin is impregnated using a crosshead while pulling the reinforcing fiber bundle. 3. The reinforcing fiber obtained by the method according to claim 1 or 2, wherein the reinforcing fibers are arranged substantially continuously over the entire length of the structure in a substantially parallel manner. Strand, pellet, tape or sheet fiber reinforced thermoplastic resin structure.