Method for producing sizing agent-coated carbon fibers, and sizing agent-coated carbon fibers

A method for producing sizing agent-coated carbon fibers coated with at least one sizing agent [a],

• wherein a di- or higher functional epoxy compound (A1) selected from the group consisting of a phenol novolac type epoxy resin, a cresol novolac type epoxy resin, bisphenol A diglycidyl ether, and tetraglycidyldiaminodiphenylmethane and/or a mono or higher functional epoxy compound (A2) selected from the group consisting of sorbitol type polyglycidyl ether, glycidyl phthalimide and urea modified epoxy resin are/is used as component (A),
• wherein the epoxy equivalent of the component (A) Is less than 360 g/mol, said method comprising the steps of:
• coating carbon fibers 100 parts by mass with said sizing agent of 0.1 to 10 parts by mass;
• and
• heat-treating in a temperature range from 160 to 260°C for 30 to 500 seconds;
• wherein [a] is a sizing agent obtained by mixing at least 0.1 to 25 parts by mass of a tertiary amine compound and/or tertiary amine salt (B1) with a molecular weight of 100 g/mol or higher used as component (B), with 100 parts by mass of the component (A),
• wherein the tertiary amine compound and/or tertiary amine salt (B1) with a molecular weight of 100 g/mol or higher or the abovementioned [a ]is a tertiary amine compound and/or tertiary amine salt represented by the following general formula (III):
• where R8 denotes any one of a hydrocarbon group with 1 to 22 carbon atoms, a group containing a hydrocarbon with 1 to 22 carbon atoms and an ether structure, a group containing a hydrocarbon with 1 to 22 carbon atoms and an ester structure, and a group containing a hydrocarbon with 1 to 22 carbon atoms and a hydroxyl group;
• and where R9 denotes an alkylene group with 3 to 22 carbon atoms and may also contain an unsaturated group;
• and R10 any one of a hydrogen, a hydrocarbon group with 1 to 22 carbon atoms, a group containing a hydrocarbon with 1 to 22 carbon atoms and an ether structure, a group containing a hydrocarbon with 1 to 22 carbon atoms and an ester structure, and a group containing a hydrocarbon with 1 to 22 carbon atoms and a hydroxyl group;
• or R8 and R10 may be combined with each other to form an alkylene group with 2 to 11 carbon atoms, or the following general formula (V):
• where R14 to R17 denote, respectively independently, any one of a hydrocarbon group with 1 to 22 carbon atoms, a group containing a hydrocarbon with 1 to 22 carbon atoms and an ether structure, a group containing a hydrocarbon with 1 to 22 carbon atoms and an ester structure, and a group containing a hydrocarbon with 1 to 22 carbon atoms and a hydroxyl group, or the following general formula (VI):
• where R18 to R24 denote, respectively independently, any one of a hydrocarbon group with 1 to 22 carbon atoms, a group containing a hydrocarbon with 1 to 22 carbon atoms and an ester structure, a group containing a hydrocarbon with 1 to 22 carbon atoms and an ester structure, and a group containing a hydrocarbon with 1 to 22 carbon atoms and a hydroxyl group.