Patent ID: 7150913

Claim:
A sizing agent for carbon fiber, comprising 100 parts by weight of a component (A) described below, and from 10 to 75 parts by weight of a component (B) described below, wherein a combined total of said component (A) and said component (P) accounts for at least 50% by weight of a combined weight of all components: component (A): a compound with at least 1 epoxy group within each molecule, and with a surface energy at 125° C. of 17 to 34 mJ/m 2 ; and component (B): a compound with at least 1 epoxy group within each molecule, and with a surface energy at 125° C. of at least 35 mJ/m 2 , further comprising from 8 to 30% by weight, relative to a combined weight of all components, of a component (D) formed from an anionic surfactant with an aryloxy group as a hydrophobic group, with an ammonium ion as a counter ion, and with an alkylene oxide addition quantity of no more than 10 moles, wherein said compound with an epoxy group that constitutes said component (A) is a component (A′) formed from a compound with at least 2 epoxy groups within each molecule, and said compound with an epoxy group that constitutes said component (B) is a component (B′) formed from a compound with at least 2 epoxy groups within each molecule.