| abstract |
Provided is a fiber sizing agent that can be used in the production of a fiber bundle capable of imparting excellent strength to a molded article and has excellent fiber sizing properties. A fiber sizing agent comprising a urethane resin (A) having an alkoxypolyoxyalkylene structure and an epoxy group, a compound (B) represented by the following general formula (1), and an aqueous medium (C). Then, a fiber sizing agent characterized by having a Hansen solubility parameter of solid content in the range of 19.00 to 21.50 J 1/2 / cm 3/2 is used. (In the formula, R is a hydrocarbon group having 1 to 40 carbon atoms or a hydrogen atom, X is —O— or —COO—, A is an alkylene group other than ethylene group, and E is ethylene. M is an integer of 0 to 200, and n is an integer of 1 to 350. Furthermore, the repeating unit containing A and the repeating unit containing E are arranged in a random or block form. That is.) [Selection figure] None |