Patent ID: 8114936

Claim:
A sizing agent composition comprising: a synthetic sizing agent; and a cationic polymer obtained by copolymerizing (1) a vinyl monomer selected from the group consisting of the formula (I), formula (Ia), and combinations thereof, wherein formula (I) and formula (Ia) are as follows: CH 2 ═CR 1 —COA(CH 2 ) n N + R 2 R 2 R 3 X − (I) (CH 2 ═CHCH 2 ) 2 N + (R 2 ) 2 X − (Ia) wherein R 1 is a hydrogen atom or a methyl group, A is an oxygen atom or NH group, n is 2 or 3, R 2 and R 3 are each a methyl group or an ethyl group and X is a chlorine atom, a bromine atom, or k is a methyl sulfate ion; and (2) a vinyl monomer of the formula: CH 2 ═CR 4 —CONH 2 (II) wherein R 4 is a hydrogen atom or a methyl group; and (3) a vinyl monomer selected from the group consisting of formula (III), (IIIa), and combinations thereof, wherein formula (III) and (IIIa) are as follows: CH 2 ═CR 5 COO(CH 2 ) n OH (III) CH 2 ═CR 6 COO(CH 2 ) m CHOHCH 2 OH (IIIa) wherein R 5 and R 6 is a hydrogen atom or a methyl group, n is 1-4, inclusive and m is 1 or 2.