Patent ID: 7413785

Claim:
A heat shrinkable foamed polymer tube consisting essentially of (A) a first layer of an extruded foamed polymer tube, said first layer being an inner layer of said tube, having a void content and comprising (1) at least one base polymer; and (2) a blowing agent, said blowing agent comprising: (a) a plurality of polymeric shells; and (b) at least one heat-activated chemical compound, said heat-activated chemical compound encapsulated in said polymeric shells, and (B) a second layer of said extruded foamed polymer tube, said second layer being an outer layer of said tube in contact with the first layer, having a void content and comprising (1) at least one base polymerdifferent than the base polymer of the first layer; and (2) a blowing agent, said blowing agent comprising: (a) a plurality of polymeric shells; and (b) at least one heat-activated chemical compound, said heat-activated chemical compound encapsulated in said polymeric shells.