Processing Aids and Polymer Formulations Containing the Same and Method for Producing the Same

A multi-stage emulsion processing aid polymer comprising

• from 25 to 75 percent by weight first stage polymer which comprises units derived from non-functional ethylenically unsaturated monomer;
• and
• from 25 to 75 percent by weight second stage polymer which comprises 0 to 99.6 mole % units derived from one or more non-functional ethylenically unsaturated monomer(s) and 0.4 to 100 mole % units derived from one or more functionalized ethylenically unsaturated monomer(s) into the emulsion polymerization reactor, wherein the functionality is selected from the group consisting of β-keto esters, β-keto amides, β-diketones, cyanoacetic esters, malonates, nitroalkanes, β-nitro esters, sulfonazides, thiols, thiol-s-triazines, and amine, where the functionality is incorporated into polymers by polymerizing, ethylenically unsaturated monomers containing these functionalities or by post functionalization of a polymer with additional reactions after polymerization;
• and
• wherein the processing aid polymer has a Mw equal to or greater than 700,000.