Waterproofing and breathable polyolefin roofing membrane by extrusion lamination and sequential stretching
AssigneesDdp Specialty Electronic Materials US, LLC, Eidca Specialty Products Company, Dupont (China) Research & Development and Management Co., Ltd.
InventorsWENYI HUANG, LISA BERTOLO, JIAQUI WANG
Life of this patent
Estimating the term…
Abstract
Reinforced microporous polyolefin sheets comprise one or more layers of a microporous polyolefin and a non-woven fabric at least partially embedded in the microporous polyolefin. The reinforced microporous polyolefin sheet is made in an extrusion lamination process by which a polyolefin sheet and non-woven fabric are laminated, followed by sequential cold and hot stretching steps to produce the micropores.
Claims2
A reinforced microporous polymer sheet having a thickness of at least 1 mm comprising a non-woven fabric embedded in a microporous polyolefin
- wherein the non-woven fabric has an areal weight of 100 to 400 g/m2, a thickness of 0.25 to 0.95 mm under a load of 2 kN/m2, and an elongation to break of 30 to 200% in each of machine and cross directions and
- wherein the polyolefin is a phase-segregated polymer that comprises a continuous phase comprising a polypropylene homopolymer and a dispersed phase comprising an ethylene-propylene copolymer having a glass transition temperature of −30° C. or lower, the dispersed phase further containing inclusions of a polypropylene homopolymer.
A reinforced microporous polymer sheet having a thickness of at least 1 mm comprising a non-woven fabric embedded in a microporous polyolefin
- wherein the non-woven fabric has an areal weight of 100 to 400 g/m2, a thickness of 0.25 to 0.95 mm under a load of 2 kN/m2, and an elongation to break of 30 to 200% in each of machine and cross directions and
- wherein the polyolefin comprises
- (i) 50 to 95 weight percent of one or more polypropylene homopolymer chain segments, based on the weight of the polyolefin, or 43 to 79 mole percent polypropylene homopolymer chain segments based on the mold content of polymerized units of polypropylene in the polypropylene homopolymer chain segments as a percentage of the total mole content of polymerized monomer units in the polyolefin and
- (ii) 5 to 50 weight percent of ethylene-containing copolymer chain segments based on the weight of the polyolefin, or 21 to 57 mole percent of ethylene-containing chain segments based on the mole content of polymerized monomer units in the ethylene-containing copolymer chain segments as a percentage of the total mole content of polymerized monomer units in the polyolefin, and
- wherein at least a portion of the ethylene-containing copolymer chain segments comprise polymerized units of ethylene in an amount of at least 45 weight percent based on the weight of the ethylene-containing copolymer chain segments, or at least 55 mole percent based on the mole content of polymerized units of ethylene in the ethylene-containing chain segments as a percentage of the total mole content of polymerized monomer units in the ethylene-containing copolymer chain segments.
Dependencies are inferred from the claim text.