Ethylene interpolymer blend compositions
AssigneeThe Dow Chemical Company
InventorsBrian W. S. Kolthammer, Robert S. Cardwell, Ronald P. Markovich, Bharat I. Chaudhary, Adam E. Laubach, Jesus Nieto
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Abstract
Film, molded articles and fibers prepared from ethylene/α-olefin interpolymer compositions are disclosed. The interpolymer compositions are blends prepared by combining specified amounts of a narrow molecular weight distribution, narrow composition distribution breadth index interpolymer, and a broad molecular weight distribution, broad composition distribution breadth index interpolymer, with each blend component having a specified density, melt index and degree of branching.
Claims8
A molded article comprising an ethylene/α-olefin interpolymer composition wherein said interpolymer composition has a density of from about 0.940 to about 0.960 and a melt index, I2, of from about 3 to about 100 g/10 min;
- and comprises
- (A) an interpolymer of ethylene with at least one C3-8 α-olefin and present in an amount of from about 5 to about 50% by weight, based on the combined weight of Components A and B, and having
- (i) a narrow molecular weight distribution, defined as an Mw/Mn of less than about 3,
- (ii) a narrow composition distribution breadth index, CDBI, defined as the weight percent of the polymer molecules having a comonomer content within 50 percent of the median total molar comonomer content of Component A, which is greater than about 50 percent;
- (iii) a degree of branching less than or equal to 2 methyls/1000 carbons in about 15 percent or less by weight, based on the total weight of Component A;
- (iv) an aluminum residue content of less than or equal to about 250 ppm present in the interpolymer composition, and
- (v) a density of from about 0.850 to about 0.908 g/cm3;
- and
- (B) one or more homopolymers or interpolymers of ethylene and/or at least one C3-8 α-olefin and is present in an amount of from about 50 to about 95% by weight, based on the combined weight of Components A and B, and
- (i) has a broad molecular weight distribution, define as an Mw/Mn of greater than about 3,
- (ii) has a broad composition distribution with a degree of branching less than or equal to 2 methyls/1000 carbons in about 10 percent or more by weight, based on the total weight of Component B, and
- (iii) has a degree of branching greater than or equal to 25 methyls/1000 carbons in about 25 percent or less by weight, based on the total weight of Component B,
- and wherein
- (a) said interpolymer composition has an improvement in 23° C. Izod Impact of at least 5% over a blend of Component A and Component B having the same final melt index and density, but wherein the density of Component A is greater than or equal to 0.909 g/cm3 and
- (b) said molded article is made by rotational molding, injection molding or blow molding.
An interpolymer blend composition having a density of from about 0.940 to about 0.960 and a melt index (I2) of from about 3 to about 100 g/10 min;
- comprising
- (A) one or more ethylene/α-olefin interpolymers which;
- (i) has a narrow molecular weight distribution, defined as an Mw/Mn of less than about 3,
- (ii) has a narrow composition distribution breadth index, CDBI, defined as the weight percent of the polymer molecules having a comonomer content within 50 percent of the median total molar comonomer content of Component A, which is greater than about 50 percent;
- (iii) has a degree of branching less than or equal to 2 methyls/1000 carbons in about 15 percent or less by weight, based on the total weight of Component A;
- (iv) has an aluminum residue content of less than or equal to about 250 ppm present in the interpolymer composition, and
- (v) is present in an amount of from about from about 5 to about 50% by weight, based on the combined weight of Components A and B;
- and
- (vi) has a density of from about 0.850 to about 0.908 g/cm3;
- and
- (B) an ethylene/α-olefin interpolymer;
- which
- (i) has a broad molecular weight distribution, defined as defined as an Mw/Mn of greater than about 3,
- (ii) has a broad composition distribution with a degree of branching less than or equal to 2 methyls/1000 carbons in about 10 percent or more by weight, based on the total weight of Component B,;
- (iii) has a degree of branching greater than or equal to 25 methyls/1000 carbons in about 25 percent or less by weight, based on the total weight of Component B;
- and
- (iv) is present in an amount of from about 50 to about 95% by weight, based on the combined weight of Components A and B,;
- and wherein
- (C) said interpolymer composition has an improvement in 23° C. Izod Impact of at least 5% over a blend of Component A and Component B having the same final melt index and density, but wherein the density of Component A is greater than or equal to 0.909 g/cm3.
Dependencies are inferred from the claim text.