| 摘要 |
A phosphorus-atom-containing oligomer is used as a curing agent for epoxy resin, the phosphorus-atom-containing oligomer being a mixture of a phosphorus-atom-containing compound represented by structural formula (1) below with n representing 0 and a phosphorus-atom-containing oligomer represented by structural formula (1) below with n representing 1 or more: (where R1 to R5 each independently represent a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, or the like; X represents a hydrogen atom or a structural unit represented by structural formula (x1) below: where, in structural formula (x1), R2 to R5 each independently represent a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, or the like), wherein a content of the phosphorus-atom-containing oligomer represented by general structural formula (1) with n representing 1 or more is in the range of 5 to 90% on a peak area basis in GPC measurement. |
