Reinforced fiber/resin fiber composite, and method for manufacturing same

Abstract

A reinforced fiber/resin fiber composite is provided in which the ratio and arrangement of a long fiber and a thermoplastic resin fiber included in an intermediate material are accurately controlled to simultaneously provide good impregnation characteristics of the long fiber and good interfacial characteristics between the long fiber and the thermoplastic resin. A reinforced fiber/resin fiber composite (50) is provided which is an intermediate material for a long-fiber reinforced thermoplastic resin structure. The reinforced fiber (15) is a long fiber extending in a longitudinal direction. The resin fiber (25) includes at least two thermoplastic resin fibers. The at least two thermoplastic resin fibers are arranged around the reinforced fiber (15) to surround the reinforced fiber (15).

Description

TECHNICAL FIELD[0001]The present invention relates to reinforced fiber / resin fiber composites which are an intermediate material for a long-fiber reinforced thermoplastic resin structure, and methods for manufacturing the same.BACKGROUND ART[0002]Fiber reinforced thermoplastic resins, which are a combination of a thermoplastic resin and a fiber, have good properties, i.e., light weight and high strength, and therefore, are used in a variety of fields. For example, in transport machines, such as automobiles, ships, aircrafts, etc., molded products of fiber reinforced thermoplastic resins are used as a portion of parts to improve fuel efficiency and safety.[0003]As a type of fiber reinforced thermoplastic resin, fiber reinforced plastics (FRPs), which are a molded product of a thermoplastic resin to which a short fiber is added, have been well known. In recent years, a long-fiber reinforced thermoplastic resin, which is a combination of a thermoplastic resin and a long fiber (e.g., a ...

AI Technical Summary

Benefits of technology

[0039]According to the method for manufacturing the reinforced fiber / resin fiber composite having this configuration, advantages similar to those of the reinforced fiber / resin fiber composite described above can be obtained.

[0040]Specifically, a hybrid resin fiber including the at least two thermoplastic resin fibers is provided around the long fiber. When the reinforced fiber / resin fiber composite having such a form is processed by thermoforming, then if the at least two thermoplastic resin fibers are suitably selected, the reinforced fiber can be reliably impregnated to the inside thereof with the thermoplastic resin, for example, when the thermoplastic resin fiber surrounding the reinforced fiber is melted, and at the same time, interfacial characteristics between the reinforced fiber and the thermoplastic resin can be improved. As a result, the reinforced fiber and the thermoplastic resin can be prevented from coming off the interface therebetween. Note that melting of the thermoplastic resin fiber during thermoforming, which is a type of so-called in-situ polymer blend, can be easily carried out.

[0041]Moreover, the method for manufacturing the reinforced fiber / resin fiber composite having this configuration employs a “braiding technique” which is known as a traditional craft. In the braiding technique, strands (fiber) can be braided into various arrangement patterns by modifying the braiding pattern. Therefore, if the braiding technique is applied to the reinforced fiber / resin fiber composite manufacturing method, the mixture ratio of the reinforced fiber and the thermoplastic resin, or the composition ratio of the at least two thermoplastic resins, can be flexibly controlled, depending on the pattern in which strands are braided. In addition, if the braiding technique is used, strands (fiber) are not opened, and therefore, the fiber is not likely to be damaged.

[0042]Also, in the braiding technique, when a plurality of strands (fiber) are braided, the arrangement of the strands (fiber), and tension exerted on the strands (fiber), can be controlled on a strand-by-strand basis. Therefore, the method for manufacturing the reinforced fiber / resin fiber composite having this configuration is particularly effective in accurately controlling the structure and composition of the long-fiber reinforced thermoplastic resin structure as a final product. Therefore, if the braiding technique is used, the physical properties of each resin fiber can be imparted, in a desired form, to the long-fiber reinforced thermoplastic resin structure after thermoforming.

Problems solved by technology

On the other hand, in the long-fiber reinforced thermoplastic resin, the thermoplastic resin has a very high melt viscosity, and therefore, it is disadvantageously difficult to impregnate the long fiber with the thermoplastic resin.

As the impregnation characteristics of the resin decrease, the molded product cannot exhibit sufficient strength.

If the interfacial characteristics are insufficient, the long fiber and the thermoplastic resin are likely to come off the adhesion surface therebetween, so that the molded product is likely to be damaged.

Here, generally, as the impregnation characteristics of the thermoplastic resin with respect to the long fiber become better, the interfacial characteristics between the long fiber and the thermoplastic resin become worse.

For example, when the surface of the long fiber is modified by acid modification etc. in order to improve the interfacial characteristics, the contact angle of the thermoplastic resin with respect to the long fiber increases (i.e., the wettability of the long fiber surface deteriorates), and as a result, the impregnation characteristics become worse.

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