Additives for paper

Claim 1

ADDITIVES USEFUL FOR INCREASING THE RETENTION OF FIBERS AND FILLERS IN THE PRODUCTION OF PAPER OR IN THE TREATMET OF SEWAGE COMPRISING COPOLYMES CONSISTING ESSENTIALLY OF 85 TO 95% BY WEIGHT OF STATISTICALLY DISTRIBUTED POLYMERIC UNITS OF MANNICH BASES CORRESPONDING TO THE FORMULA: -CH2-C(-R)(-CO-NH-CH2-N(-R1)-R2)WHEREIN R IS HYDROGEN OR METHYL, R1 IS HYDROXYALKYL HAVING 2 TO 3 CARBON ATOMS, R2 IS AKYL HAVING 1 TO 2 CARBON ATOMS, R1 AND R2 ARE EACH HYDROXYALKYL HAVING 2 TO 3 CARBON ATOMS, R1 AND R2 TOGETHER WITH THE NITROGEN ATOM TO WHICH THEY ARE ATTACHED ARE PYRROLIDIONE, MORPHOLINO, N-METHYLPIPERAZINO OR N-ETHYLPIPERAZINO AND 15 TO 5% BY WEIGHT OF SATISTICALLY DISTRIBUTED POLYMERIC UNITS OF THE FORMULA: -CH-C(-R)(-COO-A-N(+)(-R3)(-R4)-R5)- X(-) WHEREIN R IS HYDROGEN OR METHYL, A IS ALKYLENE HAVING 2 TO 4 CARBON ATOMS, R3 IS HYDROGEN OR ALKYL HAVING 1 TO 4 CARBON ATOMS, R4 AND R5 ARE ALKYL HAVING 1 TO 4 CARBON ATOMS X(-) IS A NEGATIVE GROUP CAPABLE OF SALT FORMATION WITH THE AMINE NITROGEN SELECTED FROM THE GROUP CONSISTING OF HALIDE, ACETATE, METHOSULPHATE AND TOLYLSUPHATE.