Carbon fiber bundle process for producing the same and thermoplastic resin composition and molded article thereof

Abstract

A carbon fiber bundle is provided which can develop satisfactory interfacial adhesion to polyolefin-based resins, especially polypropylene resins. The carbon fiber bundle comprises a plurality of single fibers that was sized with a sizing agent comprising: a polymer having a main chain formed of carbon-carbon bonds, containing an acid group in at least part of side chains or at least a part of main chain ends, and representing an acid value of 23 to 120 mgKOH / g as measured in accordance with ASTM D1386; or a polymer having a main chain formed of carbon-carbon bonds and containing at least either of an epoxy group and an ester group in at least a part of side chains or at least a part of main chain ends.

Description

TECHNICAL FIELD [0001] The present invention relates to a carbon fiber bundle, and method for producing the same, which can be used as a thermoplastic reinforcing material. The present invention further relates to a thermoplastic resin composition, and molded article thereof, which uses such a carbon fiber bundle. BACKGROUND ART [0002] A carbon fiber bundle is a form gathering together a plurality single fibers consisting of carbon, and is used as a reinforcing material for thermoplastic resins or the like. [0003] When used as a reinforcing material for thermoplastic resins, carbon fiber bundles are usually supplied being a form cut into lengths of 5 to 15 mm. During production of pellets obtained by kneading this carbon fiber bundles and a thermoplastic resin, it is necessary to supply the carbon fiber bundles in a fixed quantity into an extruder. In order to do this, the form stability of the carbon fiber bundles is important. A form that is not suitable can become a cause for dis...

AI Technical Summary

Benefits of technology

"The present invention provides a carbon fiber bundle that can develop good adhesion with polyolefin-based resins, especially polypropylene resin. The carbon fiber bundle is sized with a specific polymer and has a specific surface treatment. The resulting carbon fiber bundle can be used as a reinforcing material in thermoplastic resin compositions, which can be molded to create various articles. The technical effect of the invention is to provide a reliable and effective solution for improving the interfacial adhesion between carbon fibers and polyolefin-based resins."

Problems solved by technology

A form that is not suitable can become a cause for discharge unevenness.

Also, because a fixed extrusion rate cannot be attained, strand breakage occurs, whereby there is the risk of pellet productivity dramatically falling.

During this process, fluff or fly is easily formed on the carbon fiber bundle, or, the bundle is easily loosened, so that the handling is difficult.

Recently, however, the number of cases of using a polyolefin-based resin has been increasing for reasons of recyclability and cost.

Since polyolefin-based resins are basically nonpolar, their interfacial adhesion with the carbon fibers or glass fibers is extremely poor and the effects of improved mechanical properties as a reinforcing material cannot be adequately expressed in many cases.

However, in the method which adds an acid modified polyolefin-based resin to the matrix resin, a large amount of acid modified polyolefin-based resin has to be added, whereby a product having excellent recyclability and cost effectiveness cannot be obtained.

Further, although the method sizing with a sizing agent having acid modified polypropylene as an essential component described in Patent Document 1 achieves good interfacial adhesion as compared with a polyolefin-based resin, in the case of carbon fibers the effects were not sufficient.