Surface sizing of paper using salt of random copolymer - of alpha:olefin!, acrylic! or methacrylic! acid and cyclic (N)-vinyl!-amide!

摘要

Sizing is carried out with a soln. of a water-soluble salt of a copolymer (I) of 50-89.5 (wt.)% 2-12C alpha-olefins (II), 10 50% (meth)acrylic acid (II), 0.5-2% cyclic N-vinylamide (IV) and 0-30% other ethylenically unsatd. cpds. (V). (I) has a K value of 15-40. (IV) are N-vinyl-lactams with 6-13C in the lactam ring and/or N-vinylbenzopyrrolidone. In an example, the use of a copolymer of 79% styrene, 20% acrylic acid and 1% vinylcaprolactam in an aq. paper sizing compsn. increased the ink penetration time to 19 mins., cf. 3 mins. using a copolymer of 80% styrene and 20% acrylic acid, both copolymers being used in the form of ammonium salts. (I) salt gives a better sizing effect than salts of copolymers, of K value 30-55, contg. no (IV) component.