Patent ID: 7022745

Claim:
A process for preparing solid polymeric pressure sensitive adhesive microspheres comprising: (a) contacting a polymerizable aqueous emulsion of at least one non-ionic monomer of an alkyl acrylate or alkyl methacrylate ester of a non-tertiary alcohol and at least one acid monomer copolymerizable with said non-ionic monomer and at least one strong electrolyte selected from alkali metal, alkaline earth metal, or ammonium salts of inorganic or organic acids having a K a equal to or greater than the K a of acetic acid,; and (b) polymerizing the emulsion to form an aqueous suspension of said solid polymeric pressure sensitive adhesive microspheres; wherein at least an amount of said strong electrolyte effective to produce polymeric pressure sensitive adhesive solid microspheres is contacted with the polymerizable aqueous emulsion prior to the start of polymerization, wherein said process utilizes at least one emulsifier in a concentration greater than the critical micelle concentration; and wherein said solid polymeric microspheres have improved adhesion performance characteristics.