Polymeric membrane compositions
AssigneeExxonMobil Chemical Patents Inc.
InventorsRaja N. Dharmarajan, Thomas C. Yu
Life of this patent
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Abstract
Blends of very low density polyethylene produced using metallocene catalysts (mVLDPE) and polypropylene are disclosed. The polymer blends include a metallocene-catalyzed VLDPE polymer having a density of less than 0.916 g/cm3, the mVLDPE polymer preferably being linear and without long chain branching, a polypropylene homopolymer, random copolymer, or impact copolymer, and optionally flame retardant additives. The polymer blends are particularly suitable in membrane applications where increased tear resistance and tensile strength are desirable, such as in roof membranes, geomembranes, and pond liners.
Claims55
A membrane formed from a polymer blend composition comprising:
- (a) a metallocene-catalyzed VLDPE copolymer of ethylene and one or more C3-C20 alpha olefin comonomers, the copolymer having a density of from 0.906 g/cm3 to 0.915 g/cm3, and
- (b) a polypropylene polymer component,
- wherein components (a) and (b) are present in the blend composition in a weight ratio of from 9:1 to 1:9.
A membrane formed from a polymer blend composition comprising:
- (a) a metallocene-catalyzed VLDPE copolymer of ethylene and one or more C3-C12 alpha olefin comonomers, the copolymer having a density of from 0.906 g/cm3 to 0.915 g/cm3, and
- (b) a polypropylene polymer component comprising at least one of a polypropylene homopolymer and a polypropylene/ethylene copolymer having a polymerized ethylene content of from 0.5 to 40 wt. %,
- wherein components (a) and (b) are present in the blend composition in a weight ratio of from 9:1 to 1:1.
A composite membrane comprising first and second layers, and an intermediate polymeric reinforcing layer disposed between the first and second layers, wherein the first and second layers are the same or different and are formed from a polymer blend composition comprising:
- (a) a metallocene-catalyzed VLDPE copolymer of ethylene and one or more C3-C20 alpha olefin comonomers, the copolymer having a density of from 0.906 g/cm3 to 0.915 g/cm3, and
- (b) a polypropylene polymer component,
- wherein components (a) and (b) are present in the blend composition in a weight ratio of from 9:1 to 1:9.
A membrane formed from a polymer blend composition comprising:
- (a) a copolymer of ethylene and one or more C3-C20 alpha olefin comonomers, the copolymer having:
- (i) a comonomer content of from 5 to 15 wt. %,
- (ii) a density of less than 0.916 g/cm3,
- (iii) a composition distribution breadth index of from 50% to 85%,
- (iv) a molecular weight distribution Mw/Mn of from 2 to 3,
- (v) a molecular weight distribution Mz/Mw of less than 2, and
- (vi) a bimodal composition distribution;
- and
- (b) a polypropylene polymer component,
- wherein components (a) and (b) are present in the blend composition in a weight ratio of 9:1 to 1:9
A composite membrane comprising first and second layers, and an intermediate polymeric reinforcing layer disposed between the first and second layers, wherein the first and second layers are the same or different and are formed from a polymer blend composition comprising:
- (a) a metallocene-catalyzed VLDPE copolymer of ethylene and one or more C3-C20 alpha olefin comonomers, the copolymer having:
- (i) a comonomer content of from 5 to 15 wt. %,
- (ii) a density of less than 0.916 g/cm3,
- (iii) a composition distribution breadth index of from 50% to 85%,
- (iv) a molecular weight distribution Mw/Mn of from 2 to 3,
- (v) a molecular weight distribution Mz/Mw of less than 2, and
- (vi) a bimodal composition distribution;
- and
- (b) a polypropylene polymer component,
- wherein components (a) and (b) are present in the blend composition in a weight ratio of from 9:1 to 1:9.
Dependencies are inferred from the claim text.