| 摘要 |
PROBLEM TO BE SOLVED: To obtain a polymer useful for fixing especially a dye, a pigment, etc., as a cationic water soluble polymer by including specific 2 kinds of amidine structures in high contents to make the reduced viscosity of the polymer a specific value. SOLUTION: This polymer having cyclic amidine structures having 0.01-10 dl/g, preferably 0.01-6 dl/g and more preferably 0.01-5 dl/g reduced viscosity (measured at 0.1 g/dl concentration in aqueous 1 N sodium chloride solution at 25 deg.C) is obtained by including a 5-membered cyclic amidine structure of formula I (X is a protonic acid) and a 6-membered amidine structure of formula II in total >=50 mol.%. It is preferable that the copolymer contains 5-99 mol.% structure of formula I and 1-90 mol.% structure of formula II. The polymer is obtained e.g. by a method, etc., for polymerizing a mixture containing N- vinylformamide and acrylonitrile in a molar ratio of (45:55)-(95:5) in the presence of a radical polymerization catalyst in an aqueous medium, then hydrolizing the obtained polymer, removing formic acid formed and heating. |
