英文名称:duolite A-7 ion-exchange resin; Formaldehyde, polymer with N1,N2-bis(2-aminoethyl)-1,2-ethanediamine and phenol; Formaldehyde, polymer with N,N'-bis(2-aminoethyl)-1,2-ethanediamine and phenol; Formaldehyde-phenol-triethylenetetramine copolymer; Phenol condensation products, with formal