Patent ID: 7214653

Claim:
A polyalkyleneimine alkyleneoxide copolymer having a structure in which an oxyalkylene group is added to a nitrogen atom of a polyalkyleneimine unit composed of alkyleneimine, wherein the polyalkyleneoxide has an end structure containing at least one selected from the group consisting of; (1) —CO—R 2 —COOX; (2) —CH 2 CH(OH)—R 3 ; (3) —CH 2 CH(OH)CH 2 —O—R 4 ; and (4) —C(O)—NH—R 5 , wherein R 2 represents an alkylene group having 2 to 8 carbon atoms, an alkenylene group having 2 to 8 carbon atoms, an arylene group having 6 to 14 carbon atoms or a sulfoalkylene group having 2 to 8 carbon atoms; R 3 represents an alkenyl group having 2 to 6 carbon atoms, an aryl group having 6 to 14 carbon atoms, a sulfoalkyl group having 2 to 6 carbon atoms or a hydroxyalkyl group having 2 to 6 carbon atoms; R 4 represents a hydrogen atom, an alkyl group having 2 to 8 carbon atoms, an alkenyl group having 2 to 6 carbon atoms, an aryl group having 6 to 14 carbon atoms or a sulfoalkyl group having 2 to 6 carbon atoms; R 5 represents an alkyl group having 2 to 8 carbon atoms, an alkenyl group having 2 to 8 carbon atoms, an aryl group having 6 to 14 carbon atoms or a sulfoalkyl group having 2 to 6 carbon atoms; and X represents a hydrogen atom, an alkaline metal atom, an alkaline earth metal atom, an ammonium group or an organic ammonium group, wherein a content of the end structure selected from the group consisting of the groups (1) to (4) is not less than 5 mol % and not more than 100 mol % with respect to 100 mol % of all end structures of polyalkyleneoxide, wherein the polyalkyleneimine alkyleneoxide copolymer is a copolymer obtained by adding alkyleneoxide to a nitrogen atom in amine of polyamine having a structure represented by the following general formula (2); wherein R 6 s are the same or different and each represents a straight alkylene group having 2 to 6 carbon atoms or branched alkylene group having 3 to 6 carbon atoms; A represents another polyamine chain branched, and 1, m and n are the same or different and each represents an integer of 0 or 1 or more and the m-to-n ratio (m/n ratio) is from 4/1 to 1/4, wherein a content of the end structure selected from the group consisting of the groups (1) to (4) is not less than 20 mol % and not more than 98 mol % with respect to 100 mol % of all end structures of polyalkyleneoxide.