Patent ID: 8536241

Claim:
A continuous method for making an adhesive foam material comprising: (1) mixing at least one pressure-sensitive (meth)acryloyl polymer and a CO 2 /N 2 blowing agent mixture in an extrusion apparatus having an exit shaping orifice at a temperature to form a melt solution wherein the blowing agent is uniformly distributed throughout the polymeric material and wherein the partial pressure of the blowing agent is less than 750 psi in the polymer melt; (2) conveying the melt solution though the extrusion apparatus, wherein the system pressure in the final section of the extrusion apparatus is 250 to less than 1000 psi (1.7 to 6.9 MPa); (3) passing the solution through said exit shaping orifice and exposing the solution to atmospheric pressure, whereby the blowing agent expands causing nucleation and cell formation resulting in the melt solution foaming and solidifying at or about the time it exits the shaping orifice; (4) rapidly cooling the polymer melt to arrest cell growth and coalescence, and (5) crosslinking the resulting (meth)acryloyl foam polymer.