Patent ID: 8206553

Claim:
A method of improving retention and drainage in a papermaking process, the improvement comprising adding an associative polymer to a pulp slurry wherein the associative polymer comprises the formula: B-co-F (I) wherein B is a nonionic polymer segment comprising one or more ethylenically unsaturated nonionic monomers; F is an polymer segment comprising at least one or more ethylenically unsaturated anionic or cationic monomer; and the molar percent ratio of B:F is 99:1 to 1:99 and wherein the associative polymer has associative properties provided by an effective amount of at least one emulsification surfactant chosen from diblock or triblock polymeric surfactants, and wherein the amount of the at least one diblock or triblock surfactant to monomer is at least about 3:100 and wherein the associative polymer is produced in a polymerization reaction by utilizing a first plurality of charges of initiator added during the first two hours of the polymerization reaction in the production of the associative polymer followed by one or more additional charges thereafter and, wherein the number of charges added during the first two hours exceeds the number of charges added thereafter, wherein the first plurality of charges of initiator are added as an initial charge of initiator followed by one to five additional discrete charges of initiator added at a period of time after said initial charge of initiator is stopped and after at least 5% completion of the polymerization reaction; and wherein at least one additional discrete final charge of initiator is added after said one to five additional discrete charges of initiator is stopped.