The present invention relates to a method for manufacturing precursor yarn comprising lignin, which may be further processed into intermediate carbon fibers and finally also carbon fibers. It also relates to carbon fibers and uses of said fibers. Said method involves applying a water-free spin finish.

The present invention relates to a method for manufacturing precursor yarn comprising lignin, which may be further processed into intermediate carbon fibers and finally also carbon fibers. It also relates to carbon fibers and uses of said fibers. Said method involves applying a water-free spin finish.

The present invention relates to a functionalized carbon nanoparticle prepared by modifying the surface of a carbon nanoparticle with C.sub.5-10 aryl or heteroaryl substituted with one or more hydroxyl groups, and a functional polymer fiber bound therewith. The functionalized carbon nanoparticles according to the present invention are tightly bound to the polymer fiber, thereby providing the polymer fiber with the properties of carbon nanoparticle. The properties of the carbon nanoparticle being further provided in addition to those of the polymer fiber, the polymer fiber is expected to further expand its scope of application.

The present invention relates to a functionalized carbon nanoparticle prepared by modifying the surface of a carbon nanoparticle with C.sub.5-10 aryl or heteroaryl substituted with one or more hydroxyl groups, and a functional polymer fiber bound therewith. The functionalized carbon nanoparticles according to the present invention are tightly bound to the polymer fiber, thereby providing the polymer fiber with the properties of carbon nanoparticle. The properties of the carbon nanoparticle being further provided in addition to those of the polymer fiber, the polymer fiber is expected to further expand its scope of application.

Disclosed is a method for producing a sizing agent-coated carbon fibers, wherein at least one kind of sizing agent that is selected from the group consisting of sizing agents (a), (b) and (c) is used for coating, in each of the sizing agents a bi- or higher functional epoxy compound (A1) and/or an epoxy compound (A2) being used as a component (A), and the epoxy compound (A2) having a mono- or higher functional epoxy group and at least one functional group that is selected from among a hydroxyl group, an amide group, an imide group, a urethane group, a urea group, a sulfonyl group and a sulfo group. The sizing agent is applied to carbon fibers and the resulting is subjected to a heat treatment within the temperature range of 160-260 C. for 30-600 seconds.

Disclosed is a method for producing a sizing agent-coated carbon fibers, wherein at least one kind of sizing agent that is selected from the group consisting of sizing agents (a), (b) and (c) is used for coating, in each of the sizing agents a bi- or higher functional epoxy compound (A1) and/or an epoxy compound (A2) being used as a component (A), and the epoxy compound (A2) having a mono- or higher functional epoxy group and at least one functional group that is selected from among a hydroxyl group, an amide group, an imide group, a urethane group, a urea group, a sulfonyl group and a sulfo group. The sizing agent is applied to carbon fibers and the resulting is subjected to a heat treatment within the temperature range of 160-260 C. for 30-600 seconds.