JPH0550519A - Fiber reinforced thermoplastic resin structure and manufacture thereof - Google Patents

Abstract

PURPOSE:To provide the efficient and economical manufacturing method of fiber reinforced thermoplastic resin structure, which is reinforced by long fiber so as to develop high mechanical strength and, at the same time, and has much improved dispersion properties and the like of reinforcing fibers. CONSTITUTION:In order to manufacture fiber reinforced thermoplastic resin structure containing 5-80wt.% of reinforcing fibers, which are removed in the form of continuous reinforcing fiber bundle from reinforcing fiber bundle aggregate, impregnated with molten thermoplastic resin under the condition being drawn and substantially arranged parallel to one another, as the reinforcing fiber bundle, reinforcing fiber bundle, which is obtained by rewinding the wound body of fiber bundle under the condition being prepared by once winding up the sized and bundled as wetted and, after that, continuously removed under wet state from the wound body and dried, is employed.

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. Also, 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 it becomes impossible to operate due to increased fluffing. There is also.

[0003]

Means for Solving the Problems As a result of intensive studies for solving the above problems, the present inventors have found that the resin has good impregnation property and adhesion between the resin and the fiber, and has high mechanical strength. In order to efficiently obtain a fiber-reinforced thermoplastic resin structure whose dispersibility and the like are 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 manufacturing a resin structure, as a reinforcing fiber bundle, the sizing-treated and bundled fiber bundle is once wound in a wet state, and then the wound fiber bundle is continuously wound into a wet fiber bundle. The present invention relates to a method for producing a fiber-reinforced thermoplastic resin structure characterized by using a fiber bundle for reinforcement obtained by rewinding while taking it out and drying it, and a fiber-reinforced thermoplastic resin structure obtained by the production method. It is a thing.

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 adhered locally is extremely large, and particularly, the concentration of sizing agent becomes particularly high on both end surfaces of the wound cylindrical roving package, near the outer circumference and the inner circumference of the cylinder. It turned out that 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, poor impregnation of the resin, poor adhesion between the resin and the fiber, and the resulting reinforced resin structure from the reinforced resin structure. Easily disintegrates and scatters, which is the root cause of damaging the work environment and impairing moldability.
Furthermore, it has been clarified that this is a cause of poor dispersion of reinforcing fibers when such a reinforced resin structure is molded. The present invention was made on the basis of such findings, and as a reinforcing fiber, after winding a fiber bundle obtained by sizing and concentrating a large number of single fibers drawn from a bushing in a wet state, It is characterized in that a reinforcing fiber bundle obtained by continuously taking out a wet fiber bundle from the wound fiber bundle winding body and rewinding it while drying is used. The fiber bundle thus obtained has little local variation in the amount of the sizing agent attached, and thus the above problems are remarkably improved. There are no restrictions on the winding form of the wet fiber bundle, and either direct roll or cake winding is possible. Also,
The form in which the fiber bundle is rewound after drying is not particularly limited, but from the viewpoint of transportability and handleability, it is preferably wound in a cylindrical shape such as direct roving.

The type of sizing agent used for bundling the reinforcing fibers is not particularly limited, and examples thereof include olefin type, urethane type, polyester type, acrylic type and A type.
Any sizing agent such as S resin type or epoxy type is possible. 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 roving (fiber bundle) having a fiber diameter of 6 to 25 μm 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 content of such reinforcing fibers is 5 to 80% by weight based on the total weight. If the content of the reinforcing fiber is less than 5% by weight, a sufficient reinforcing effect cannot be obtained. On the contrary, 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 molding method is used for producing 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.

[0009]

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 wet glass fiber bundle which had been treated with an emulsion containing a sizing agent and bundled was once wound into a direct roll, and then the wet glass fiber bundle was continuously taken out and dried. By rewinding into a cylindrical shape, a glass fiber bundle wound body was obtained. A glass fiber bundle taken out from this roll is impregnated with molten polypropylene while being pulled through a crosshead, shaped, and shredded to form a pellet-shaped fiber-reinforced resin structure with a glass content of 50% by weight (A ) Got. Next, the glass fiber 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 carried out to obtain a flat plate molded product of 100 mm square.
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 which was wound by direct roll winding and dried by a usual method. The results are also shown in Table 1.

[0012]

As is apparent from the above description and Examples, in producing a long fiber reinforced thermoplastic resin structure, a sizing-treated and bundled fiber bundle is left in a wet state as a reinforcing fiber bundle. According to the method of the present invention using the reinforcing fiber bundle obtained by continuously taking out the wet fiber bundle from the wound fiber bundle winding body after winding it once and rewinding it while drying. It is possible to obtain a fiber-reinforced thermoplastic resin structure which is excellent in operability and the like and has extremely excellent dispersibility of reinforcing fibers during molding.

[0013]

[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. In manufacturing a resin structure, as a reinforcing fiber bundle, the sizing-treated and bundled fiber bundle is once wound in a wet state, and then the wound fiber bundle is continuously wound into a wet fiber bundle. A method for producing a fiber-reinforced thermoplastic resin structure, which comprises using a fiber bundle for reinforcement obtained by retrieving and rewinding it while taking it out. 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 state. Strand, pellet, tape or sheet fiber reinforced thermoplastic resin structure.