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US 6,656,581 B2Granted
Incrementally stretched non-embossed films having high moisture vapor transmission rates (MVTRs)
AssigneeClopay Plastic Products Company, Inc.
InventorsPai-Chuan Wu, Leopoldo V. Cancio
Life of this patent
Estimating the term…
Abstract
Non-embossed film products permeable to moisture vapor and which act as barriers to liquid are made by a high speed method. The microporous products have high moisture vapor transmission rates (MVTRs) on the order of about 2000 to about 4500 gms/m2/day according to ASTM E96E.
Claims23
An incrementally stretched non-embossed film having a high moisture vapor transmission rate (MVTR) comprising
- a thermoplastic polymer containing a dispersed phase of pore-forming particles selected from the group consisting of inorganic filler and an organic material,
- said film having a non-embossed surface and a thickness with incrementally stretched areas to provide microporosity by said pore-forming particles in the film having a high MVTR greater than about 2000 gms/m2/day according to ASTM E96E, said MVTR of the non-embossed film being greater than the MVTR of a comparable embossed film which is incrementally stretched under essentially the same conditions.
An incrementally stretched non-embossed film having a high moisture vapor transmission rate (MVTR) produced by a process comprising the steps of
- melt blending a thermoplastic polymer and pore-forming filler particles to form a microporous-formable thermoplastic polymer composition,
- cast extruding a non-embossed precursor film of the composition, and
- incrementally stretching the non-embossed precursor film to impart microporosity by said pore-forming particles in the film having a high MVTR greater than about 2000 gms/m2/day according to ASTM E96E, said MVTR of the non-embossed film being greater than the MVTR of a comparable embossed film which is incrementally stretched under essentially the same conditions.
Dependencies are inferred from the claim text.