Grafted thermoplastic compositions and fabricated articles therefrom
AssigneeThe Dow Chemical Company
InventorsBharat I. Chaudhary, Thoi H. Ho, Thomas Oswald, Jennifer DellaMea
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Abstract
This invention describes grafted blend compositions, processes for their preparation and fabricated articles, especially foams therefrom. The blends exhibit enhanced melt strength, melt elongation greater than or equal to about 20 mm/s, increased upper service temperature, increased modulus, and increased hardness. The grafted blend compositions have little or no high shear viscosity increase over a corresponding polymer of the same chemical composition absent the coupling agent.
Claims19
A foam comprising a grafted blend composition comprising,
- (A) one or more homopolymers or interpolymers with peak crystalline melting temperature (Tm) and/or or glass transition temperature (Tg by DSC) of 90° C. or more;
- (B) one or more homopolymers or interpolymers with peak crystalline melting temperature (Tm) and/or glass transition temperature (Tg by DSC) of 80° C. or less;
- and
- (C) at least one coupling agent;
- and wherein
- 1) the upper service temperature of said grafted blend is greater than about 80° C.;
- 2) the gel content of said grafted blend is 50 percent or less (as determined by insolubility of the gels in boiling xylene when tested according to ASTM D-2765A-84);
- 3) said grafted blend composition exhibits at least one of the following improvements relative to the same blend in the absence of Component C;
- (a) the melt strength is increased by 5% or more;
- and/or
- (b) the upper service temperature is increased by 0.5° C. or more;
- and wherein said foam has a crosslinked gel content of 50 percent or less, and a density less than 900 kilograms per cubic meter.
A foam comprising a grafted blend composition comprising,
- (A) a blend of
- 1) one or more linear or substantially linear ethylene homopolymers or interpolymers and one or more branched ethylene homopolymers or interpolymers;
- 2) one or more linear or substantially linear ethylene homopolymers or interpolymers and one or more substantially random interpolymers;
- or
- 3) one or more linear or substantially linear ethylene homopolymers or interpolymers, one or more branched ethylene homopolymers or interpolymers and one or more substantially random interpolymers;
- and
- (B) one or more coupling agents;
- and wherein said grafted blend composition has
- a) a melt strength, greater than about 8cN;
- b) a melt elongation of 20 mm/s or greater;
- c) a flexural modulus of 80,000 psi or greater;
- and
- d) a gel content which is 50 percent or less, as determined by insolubility of the gels in boiling xylene when tested according to ASTM D-2765A-84;
- and wherein said foam has a crosslinked gel content of 50 percent or less, and a density less than 900 kilograms per cubic meter.
A foam comprising a grafted blend composition comprising,
- (A) one or more olefinic polymers other than polypropylene;
- (B) one or more propylene homopolymers or interpolymers;
- and
- (C) at least one coupling agent;
- and wherein said grafted blend has
- 1) a gel content which is 50 percent or less, as determined by insolubility of the gels in boiling xylene when tested according to ASTM D-2765A-84;
- 2) a melt elongation greater than or equal to about 20 mm/s,
- 3) a melt strength greater than about 5 cN;
- and
- 4) a flexural modulus of 50,000 psi or greater;
- and
- and wherein said foam has a crosslinked gel content of 50 percent or less, and a density less than 900 kilograms per cubic meter.
Dependencies are inferred from the claim text.