Pressure sensitive adhesives

A pressure sensitive adhesive, comprising an aqueous latex emulsion having an average particle size diameter of less than or equal to about 100 nm, where the latex emulsion is prepared by a process consisting essentially of the steps;

• A) in a vessel pre-emulsifying;
• 1) a monomer mixture, consisting of
• a) at least one alkyl acrylate having at least 4 carbon atoms in the alkyl group,
• b) at least one ethylenically unsaturated carboxylic acid or its corresponding anhydride,
• c) at least one styrenic monomer, with
• 2. at least one anionic surfactant,
• 3. optionally a buffer, and
• 4. deionized water;
• B) in a separate vessel preparing an aqueous solution of an initiator;
• C) in a separate vessel preparing an aqueous solution of a reducing agent;
• D) adding up to 20% by weight of the pre-emulsion and a predetermined amount of the initiator and reducing agent to a reaction vessel with stirring,
• E) simultaneously adding to the reaction vessel over time the preemulsion, a predetermined amount of the initiator and a predetermined amount of the reducing agent where the pre-emulsion and initiator are premixed by adding to the reaction vessel through a common feed line;
• F) completing the addition of the pre-emulsion, initiator and reducing agent, adding sequentially,
• 1. an additional pre-determined amount of the initiator and
• 2. an additional pre-determined amount of the reducing agent;
• G) optionally repeating F);
• and
• H) optionally adjusting the pH to at least 6.

An aqueous latex emulsion prepared from a monomer mixture consisting essentially of;

• A) at least one alkyl acrylate having at least 4 carbon atoms in the alkyl group;
• B) at least one ethylenically unsaturated carboxylic acid or its corresponding anhydride;
• and
• C) a styrenic monomer;
• in the presence of an anionic surfactant and a redox type free radical initiator system where the aqueous latex emulsion has an average particle size diameter of less than or equal to about 100 nm.