Process for making pressure sensitive adhesive hydrogels

A process for preparing a pressure sensitive adhesive hydrogel, the process comprising:

• (A) providing an oligomeric precursor, the oligomeric precursor comprising a polyether dimethacrylate, the oligomeric precursor being associated with methacrylic acid;
• (B) providing an ethylenically unsaturated crosslinking agent selected from the group consisting of difunctional ethylenically unsaturated monomer, trifunctional ethylenically unsaturated monomer and combinations of the foregoing;
• (C) optionally providing one or more copolymerizable vinyl monomers, wherein when present, the one or more copolymerizable vinyl monomers are present in a total amount of 2 wt % to 15 wt % of the pressure sensitive adhesive hydrogel;
• (D) providing a thiol in an amount of 100 ppm to 10,000 ppm;
• (E) providing a plasticizer, the plasticizer comprising:
• MO(CH2CH2O)mH I
• wherein
• M is hydrogen or C1 through C6 alkyl;
• and
• m is an integer ranging from about 1 to about 25;
• and
• (F) free radically curing a mixture of the oligomeric precursor, the ethylenically unsaturated crosslinking agent, and the thiol in water in the presence of the methacrylic acid at a pH between about 3.5 and about 9 to provide the pressure sensitive adhesive hydrogel,
• wherein the plasticizer is present in a total amount of 20 wt % to 96 wt % based on a weight of the mixture, and
• wherein the amount of thiol is relative to a total amount of the mixture.