| abstract |
An improved process for the production of a substantially equimolecular copolymer of maleic acid anhydride and diisobutylene in which from 10 to 100 mole % of the anhydride groups are esterified with linear or branched aliphatic monoalcohols containing from 1 to 20 carbon atoms or with cycloaliphatic monoalcohols containing from 5 to 6 carbon atoms to form the corresponding semiesters, wherein shortly before or after the end of the solution or suspension copolymerization of maleic acid anhydride and diisobutylene a monomer corresponding to the general formula <IMAGE> in which R=H, CH3, C2H5, -OR2, -O-CO-CH3, <IMAGE> -CH2OH, -CH2O-C-CH3, R1=H , CH3 and R2=a linear or branched alkyl group containing from 1 to 4 carbon atoms, OR MIXTURES OF THESE MONOMERS WITH ONE ANOTHER ARE ADDED TO THE POLYMERIZATION MIXTURE IN QUANTITIES OF FROM 1 TO 12 MOLE %, BASED ON THE MALEIC ACID ANHYDRIDE USED. The aqueous or aqueous-alcoholic alkali, amine or ammonium salt solutions of the semiesters of the copolymer are highly effective as anionic sizing agents for paper. |