Ethylene interpolymer blend compositions

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.

We claim:  
     
         1 . A molded article comprising an ethylene/α-olefin interpolymer composition comprising; 
 (A) an ethylene/α-olefin interpolymer which; 
 (i) has a narrow molecular weight distribution, defined as an M w /M n  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 15 to about 85% by weight (based on the combined weight of Components A and B); and  
 
 (B) an ethylene/α-olefin interpolymer; which 
 (i) has a broad molecular weight distribution, defined as an M w /M n  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 15 to about 85% by weight based on the combined weight of Components A and B;  
 and wherein said molded article is made by rotational molding, injection molding or blow molding.  
 
 
     
     
         2 . The molded article of  claim 1  wherein said interpolymer composition has a density of from about 0.870 to about 0.965 g/cm 3  and a melt index (I 2 ) of from about 0.1 to about 100 g/10 min; and wherein 
 (A) Component A is an interpolymer of ethylene with at least one C 3-8  α-olefin and has a density of from about 0.865 to about 0.920 g/cm 3 , and  
 (B) Component B is an interpolymer of ethylene with at least one C 3-8  α-olefin and has a density of from about 0.915 to about 0.965 g/cm 3 .  
 
     
     
         3 . The molded article of  claim 1  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 wherein 
 (A) Component A is an interpolymer of ethylene with at least one C 3-8  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 has a density of from about 0.850 to about 0.908 g/cm3; and  
 (B) Component B is one or more homopolymers or interpolymers of ethylene and/or at least one C 3-8  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 wherein  
 (C) said interpolymer composition has an improvement in 23° C. Izod Impact of at least 5% over a blend of the same final melt index and density, but wherein the density of Component A is greater than or equal to 0.909 g/cm 3 .  
 
     
     
         4 . The molded article of  claim 1  wherein said interpolymer composition has a density of from about 0.940 to about 0.955 and a melt index (I2) of from about 3 to about 50 g/10 min; and wherein 
 (A) Component A is an interpolymer of ethylene with at least one C 3-8  α-olefin and present in an amount of from about 7 to about 50% by weight (based on the combined weight of Components A and B) and has a density of from about 0.850 to about 0.906 g/cm3; and  
 (B) Component B is one or more homopolymers or interpolymers of ethylene and/or at least one C 3-8  α-olefin and is present in an amount of from about 50 to about 93% by weight(based on the combined weight of Components A and B); and wherein  
 said interpolymer composition has an improvement in 23° C. Izod Impact of at least 7% over a blend of the same final melt index and density, but wherein the density of Component A is greater than or equal to 0.909 g/cm 3 .  
 
     
     
         5 . The molded article of  claim 4  wherein said interpolymer composition has a density of from about 0.940 to about 0.950 and a melt index (I2) of from about 3 to about 25 g/10 min; and wherein 
 (A) Component A is an interpolymer of ethylene with at least one C 3-8  α-olefin and present in an amount of from about 10 to about 50% by weight (based on the combined weight of Components A and B) and has a density of from about 0.850 to about 0.903 g/cm3; and  
 (B) Component B is one or more homopolymers or interpolymers of ethylene and/or at least one C 3-8  α-olefin and is present in an amount of from about 50 to about 90% by weight(based on the combined weight of Components A and B); and wherein  
 said interpolymer composition has an improvement in 23° C. Izod Impact of at least 10% over a blend of the same final melt index and density, but wherein the density of Component A is greater than or equal to 0.909 g/cm 3 .  
 
     
     
         6 . The molded article of  claim 1  wherein said interpolymer composition has a density of from about 0.930 to about 0.965 and a melt index (I2) of from about 0.5 to about 4 g/10 min; and wherein 
 (A) Component A is an interpolymer of ethylene with at least one C 3-8  α-olefin and present in an amount of from about 10 to about 50% by weight (based on the combined weight of Components A and B) and has a density of from about 0.850 to about 0.903 g/cm3; and  
 (B) Component B is one or more homopolymers or interpolymers of ethylene and/or at least one C 3-8  α-olefin and is present in an amount of from about 50 to about 90% by weight(based on the combined weight of Components A and B); and wherein  
 said interpolymer composition has an improvement in 0° C. Izod Impact of at least 5% over a blend of the same final melt index and density, but wherein the density of Component A is greater than or equal to 0.909 g/cm 3 .  
 
     
     
         7 . The molded article of  claim 1  wherein said interpolymer composition has a density of from about 0.935 to about 0.945 and a melt index (I2) of from about 0.5 to about 3.3 g/10 min; and wherein 
 (A) Component A is an interpolymer of ethylene with at least one C 3-8  α-olefin and present in an amount of from about 15 to about 50% by weight (based on the combined weight of Components A and B) and has a density of from about 0.850 to about 0.890 g/cm3; and  
 (B) Component B is one or more homopolymers or interpolymers of ethylene and/or at least one C 3-8  α-olefin and is present in an amount of from about 50 to about 85% by weight(based on the combined weight of Components A and B); and wherein  
 said interpolymer composition has an improvement in −20° C. Izod Impact of at least 5% over a blend of the same final melt index and density, but wherein the density of Component A is greater than or equal to 0.909 g/cm 3 .  
 
     
     
         8 . A film made from an ethylene/α-olefin interpolymer composition comprising; 
 (A) an ethylene/α-olefin interpolymer which; 
 (i) has a narrow molecular weight distribution, defined as an M w /M n  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 15 to about 85% by weight (based on the combined weight of Components A and B); and  
 
 (B) an ethylene/α-olefin interpolymer; which 
 (i) has a broad molecular weight distribution, defined as defined as an M w /M n  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 15 to about 85% by weight based on the combined weight of Components A and B;  
 and wherein said film is a cast film or a blown film or an extrusion coated film.  
 
 
     
     
         9 . A cast film of  claim 8 , said interpolymer composition having a density of from about 0.870 to about 0.965 g/cm 3 ; a melt index (I 2 ) of from about 0.1 to about 100 g/10 min; and wherein 
 (a) Component A has a density of from about 0.890 to about 0.920 g/cm 3 ; and is an interpolymer of ethylene with at least one C 3-8  α-olefin; and    (b) Component B has a density of from about 0.900 to about 0.965 g/cm 3 , and is an interpolymer of ethylene with at least one C 3-8  α-olefin.    
     
     
         10 . A cast film of  claim 8 , said interpolymer composition having a density of from about 0.900 to about 0.935 g/cm 3 ; a melt index (I 2 ) of from about 0.5 to about 10 g/10 min and an I10/I2 of from about 6.8 to about 10.5; and wherein 
 (a) Component A is present in an amount of from about 25 to about 75% by weight based on the combined weight of Components A and B; has a density of from about 0.890 to about 0.910 g/cm 3  has no high density fraction measurable by TREF and is an interpolymer of ethylene with at least one C 3-8  α-olefin; and    (b) Component B is present in an amount of from about 25 to about 75% by weight based on the combined weight of Components A and B; has a density of from about 0.915 to about 0.935 g/cm 3 ; has a high density fraction measurable by TREF and is an interpolymer of ethylene with at least one C 3-8  α-olefin.    
     
     
         11 . A blown film of  claim 8  wherein the film is fabricated using tenter frames or the double bubble process.  
     
     
         12 . A blown film of  claim 11  wherein the film is a biaxially stretched film.  
     
     
         13 . A fiber made from an ethylene/α-olefin interpolymer composition comprising; 
 (A) an ethylene/α-olefin interpolymer which; 
 (i) has a narrow molecular weight distribution, defined as an M w /M n  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 15 to about 85% by weight (based on the combined weight of Components A and B); and  
 
 (B) an ethylene/α-olefin interpolymer; which 
 (i) has a broad molecular weight distribution, defined as defined as an M w /M n  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 15 to about 85% by weight based on the combined weight of Components A and B;  
 and wherein said fiber is a staple fiber, a melt blown fiber or spun bonded fiber or gel spun fiber.  
 
 
     
     
         14 . A structure made from the fiber of  claim 13  wherein the structure is a woven or non-woven fabric.  
     
     
         15 . A fabric of  claim 14  wherein the fabric is a spunlaced fabric.  
     
     
         16 . A fabric of  claim 14  wherein the fabric is a blend of the fibers of  claim 9  with other fibers.  
     
     
         17 . A fabric of  claim 16  wherein said other fiber is cotton or PET or combinations thereof.  
     
     
         18 . 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 M w /M n  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 M w /M n  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 the same final melt index and density, but wherein the density of Component A is greater than or equal to 0.909 g/cm 3 .    
     
     
         19 . The interpolymer composition of  claim 18  having a density of from about 0.940 to about 0.955 and a melt index (I2) of from about 3 to about 50 g/10 min; and wherein 
 (A) Component A is an interpolymer of ethylene with at least one C 3-8  α-olefin and present in an amount of from about 7 to about 50% by weight (based on the combined weight of Components A and B) and has a density of from about 0.850 to about 0.906 g/cm3; and  
 (B) Component B is one or more homopolymers or interpolymers of ethylene and/or at least one C 3-8  α-olefin and is present in an amount of from about 50 to about 93% by weight(based on the combined weight of Components A and B); and wherein  
 said interpolymer composition has an improvement in 23° C. Izod Impact of at least 7% over a blend of the same final melt index and density, but wherein the density of Component A is greater than or equal to 0.909 g/cm 3 .  
 
     
     
         20 . The interpolymer composition of  claim 18  having a density of from about 0.940 to about 0.950 and a melt index (I2) of from about 3 to about 25 g/10 min; and wherein 
 (A) Component A is an interpolymer of ethylene with at least one C 3-8  α-olefin and present in an amount of from about 10 to about 50% by weight (based on the combined weight of Components A and B) and has a density of from about 0.850 to about 0.903 g/cm3; and  
 (B) Component B is one or more homopolymers or interpolymers of ethylene and/or at least one C 3-8  α-olefin and is present in an amount of from about 50 to about 90% by weight(based on the combined weight of Components A and B); and wherein  
 said interpolymer composition has an improvement in 23° C. Izod Impact of at least 10% over a blend of the same final melt index and density, but wherein the density of Component A is greater than or equal to 0.909 g/cm 3    
 
     
     
         21 . The interpolymer composition of  claim 18  having a density of from about 0.930 to about 0.965 and a melt index (I2) of from about 0.5 to about 4 g/10 min; and wherein 
 (A) Component A is an interpolymer of ethylene with at least one C 3-8  α-olefin and present in an amount of from about 10 to about 50% by weight (based on the combined weight of Components A and B) and has a density of from about 0.850 to about 0.903 g/cm3; and  
 (B) Component B is one or more homopolymers or interpolymers of ethylene and/or at least one C 3-8  α-olefin and is present in an amount of from about 50 to about 90% by weight(based on the combined weight of Components A and B); and wherein  
 said interpolymer composition has an improvement in 0° C. Izod Impact of at least 5% over a blend of the same final melt index and density, but wherein the density of Component A is greater than or equal to 0.909 g/cm 3 .  
 
     
     
         22 . The interpolymer composition of  claim 18  having a density of from about 0.935 to about 0.945 and a melt index (I2) of from about 0.5 to about 3.3 g/10 min; and wherein 
 (A) Component A is an interpolymer of ethylene with at least one C 3-8  α-olefin and present in an amount of from about 15 to about 50% by weight (based on the combined weight of Components A and B) and has a density of from about 0.850 to about 0.890 g/cm3; and  
 (B) Component B is one or more homopolymers or interpolymers of ethylene and/or at least one C 3-8  α-olefin and is present in an amount of from about 50 to about 85% by weight(based on the combined weight of Components A and B); and wherein  
 said interpolymer composition has an improvement in −20° C. Izod Impact of at least 5% over a blend of the same final melt index and density, but wherein the density of Component A is greater than or equal to 0.909 g/cm 3 .