Uniform small cell foams and a continuous process for making same
Assignee3M Innovative Properties Company
InventorsMark David Gehlsen, David Loren Vall, Craig Allen Perman, Bonnie Weiskopf Albrecht
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Abstract
A continuous method for making foams having uniform and/or small cell sizes and articles made with these foams are described. The method allows for adjusting or controlling cell size and cell size distribution by controlling temperature and/or blowing agent concentration. The foams feature small and/or uniform cell sizes and may be comprised of amorphous thermoplastic polymers, pressure sensitive adhesive compositions, and immiscible thermoplastic polymer compositions. A method for coextruding the foams is also described.
Claims10
A foam article made by a continuous machine process, the foam article comprising two or more immiscible thermoplastic polymers having cell sizes of 2 to 200 micrometers and cell size distribution polydispersity of 1.0 to 2.0 wherein the foam article has an anisotropic morphology comprising two axes perpendicular to each other, both parallel to a major surface of the foam article, said axes comprising a longitudinal axis parallel to the machine direction and a transverse axis perpendicular to the machine direction.
Dependencies are inferred from the claim text.