Production method of diblock type copolymer, diblock type copolymer and use of diblock type copolymer

摘要

PROBLEM TO BE SOLVED: To provide a surface treatment agent for powder which gives a dispersion excellent in dispersibility, fluidity and stability with time, and a dispersion containing powder treated by the surface treatment agent for powder. SOLUTION: A main chain is composed of a silicone graft copolymer block represented by the formula [I] and a polar copolymer block represented by the formula [II], and one terminal structure of the main chain is represented by the formula [III]. A diblock-type copolymer having the other terminal structure of the formula [IV]. (R1 represents a hydrogen atom or a methyl group, A represents a group containing an organopolysiloxane, n1 represents 1 ≦ n1 ≦ 50, and B is a monovalent hydrocarbon group having a polar group and having 1 to 20 carbon atoms. It represents an amino group or a hydroxyl group, n2 represents 1 ≦ n2 ≦ 50, R6 represents an alkyl group having 1 to 4 carbon atoms, R7 represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms independently of each other, and X Indicates the one represented by A in the formula [I] or B in the formula [II].) [Selection diagram] None.