Copolymer and detergent composition employing it

A detergent composition, comprising:

• at least one copolymer;
• and
• at least one surfactant;
• wherein.
• the at least one copolymer comprises as constituting units:
• a cationic vinyl monomer (A);
• and
• a vinyl monomer (B);
• wherein
• the cationic vinyl monomer (A), comprises:
• a monomer (A2) of formula (3) wherein c is 0, and
• optionally a monomer (A1) of formula (3) wherein c is 1,
• CH2═C(R5)—CO—(O)c—(NH)1-c—(CH2)d—N+R6R7R8.X− (3)
• wherein R5 is a hydrogen atom or a methyl group, each of R6 and R7 which are independent of each other, is a C1-24 alkyl group, an aryl group or an aralkyl group, R8 is a hydrogen atom, a C1-24 alkyl group, an aryl group, an aralkyl group or —CH2—CH(OH)—CH2—N+R9R10R11.Y—, each of R9 to R11 which are independent of one another, is a C1-24 alkyl group, an aryl group or an aralkyl group, each of X− and Y− which are independent of each other, is an anion, c is 0 or 1, and d is an integer of from 1 to 10,
• the vinyl monomer (B), comprises:
• a monomer of formula (1)
• CH2═C(R1)—CO—NR2R3 (1)
• wherein R1 is a hydrogen atom or a methyl group, and each of R2 and R3 which are independent of each other, is a hydrogen atom or a C1-3 alkyl group, provided that the sum of carbon numbers of R2 and R3 is from 1 to 4, or
• 2,3-dihydroxypropyl(meth)acrylate, and
• wherein
• a proportion of the cationic vinyl monomer (A) is from 25 to 45 mol % based on the entire copolymer, and
• the copolymer comprises no cross-linking agent as a component.