Peroxide treated blow molding polymers with increased weight swell and constant die swell
Ethylene-based polymers are generally characterized by a high load melt index of less than 12 g/10 min, a weight-average molecular weight from 200,000 to 550,000 g/mol, a number-average molecular weight from 18,000 to 48,000 g/mol, a CY-a parameter of less than 0.12, a tan δ at 0.1 sec −1 from 0.5 to 0.9 degrees, a tan δ at 100 sec −1 from 0.5 to 0.75 degrees, and a viscosity at 0.001 sec −1 from 1.3×10 6 to 1×10 7 Pa-sec. These ethylene polymers can be produced by peroxide-treating a bimodal molecular weight distribution dual metallocene-catalyzed resin, and can be used to produce blow molded bottles and other blow molded products.
1. An ethylene polymer having:
a density in a range from 0.945 to 0.965 g/cm 3 ;
a HLMI in a range from 1 to 12 g/10 min;
a Mw in a range from 200,000 to 550,000 g/mol;
a Mn in a range from 18,000 to 48,000 g/mol;
a CY-a parameter in a range from 0.01 to 0.12;
a tan δ at 0.1 sec −1 in a range from 0.5 to 0.9 degrees;
a tan δ at 100 sec −1 in a range from 0.5 to 0.75 degrees; and
a viscosity at 0.001 sec −1 in a range from 1.3×10 6 to 1×10 7 Pa-sec;
wherein the ethylene polymer comprises an ethylene/1-butene copolymer, an ethylene/1-hexene copolymer, an ethylene/1-octene copolymer, an ethylene homopolymer, or a combination thereof.
2. An article of manufacture comprising the polymer of claim 1 .
3. The polymer of claim 1 , wherein:
the HLMI is in a range from 2 to 10 g/10 min;
the Mw is in a range from 270,000 to 475,000 g/mol;
the Mn is in a range from 20,000 to 46,000 g/mol;
the CY-a parameter is in a range from 0.01 to 0.1;
the tan δ at 0.1 sec −1 is in a range from 0.6 to 0.8 degrees;
the tan δ at 100 sec −1 is in a range from 0.55 to 0.75 degrees; and
the viscosity at 0.001 sec −1 is in a range from 1.3×10 6 to 5.5×10 6 Pa-sec.
4. The polymer of claim 1 , wherein the polymer has a ratio of weight swell to die swell in a range from 200 to 280.
5. The polymer of claim 1 , wherein the polymer has a hang time of at least 50 sec.
6. The polymer of claim 1 , wherein the polymer contains less than 0.1 ppm by weight, independently, of Mg, V, Ti, and Cr.
7. The polymer of claim 1 , wherein the polymer further comprises an additive selected from an antioxidant, an acid scavenger, an antiblock additive, a slip additive, a colorant, a filler, a processing aid, a UV inhibitor, or any combination thereof.
8. An article of manufacture comprising the polymer of claim 7 .
9. The polymer of claim 7 , wherein the polymer has:
a zero-shear viscosity (η 0 ) in a range from 1×10 10 to 1×10 27 Pa-sec; and
a relaxation time (τ η ) in a range from 1×10 5 to 1×10 23 sec.
10. The polymer of claim 1 , wherein:
the HLMI is in a range from 1 to 10 g/10 min;
the Mw is in a range from 250,000 to 500,000 g/mol;
the Mn is in a range from 22,000 to 46,000 g/mol;
the CY-a parameter is in a range from 0.01 to 0.1;
the tan δ at 0.1 sec −1 is in a range from 0.6 to 0.85 degrees;
the tan δ at 100 sec −1 is in a range from 0.52 to 0.72 degrees; and
the viscosity at 0.001 sec −1 is in a range from 1.5×10 6 to 6×10 6 Pa-sec.
11. The polymer of claim 10 , wherein the polymer has:
a zero-shear viscosity (η 0 ) in a range from 1×10 8 to 1×10 30 Pa-sec; and
a relaxation time (τ η ) in a range from 5×10 3 to 1×10 25 sec.
12. The polymer of claim 10 , wherein the polymer has:
a viscosity at 100 sec −1 in a range from 1700 to 3300 Pa-sec; and
a Mp in a range from 65,000 to 105,000 g/mol.
13. The polymer of claim 10 , wherein the polymer has:
a ratio of Mw/Mn in a range from 7 to 17; and
a ratio of Mz/Mw in a range from 4.5 to 7.5.
14. The polymer of claim 10 , wherein the viscosity at 0.001 sec −1 is in a range from 2×10 6 to 5×10 6 Pa-sec.
15. The polymer of claim 10 , wherein the polymer has a ratio of weight swell to die swell in a range from 200 to 280.
16. An article of manufacture comprising the polymer of claim 10 .
17. A process for preparing an ethylene polymer, the process comprising:
contacting a base resin with a peroxide compound to produce the ethylene polymer, wherein the ethylene polymer is characterized by:
a density in a range from 0.945 to 0.965 g/cm 3 ;
a HLMI in a range from 1 to 12 g/10 min;
a Mw in a range from 200,000 to 550,000 g/mol;
a Mn in a range from 18,000 to 48,000 g/mol;
a CY-a parameter in a range from 0.01 to 0.12;
a tan δ at 0.1 sec −1 in a range from 0.5 to 0.9 degrees;
a tan δ at 100 sec −1 in a range from 0.5 to 0.75 degrees; and
a viscosity at 0.001 sec −1 in a range from 1.3×10 6 to 1×10 7 Pa-sec;
wherein the base resin comprises an ethylene/1-butene copolymer, an ethylene/1-hexene copolymer, an ethylene/1-octene copolymer, an ethylene homopolymer, or a combination thereof.
18. The process of claim 17 , wherein the base resin is produced using a dual metallocene catalyst system.
19. The process of claim 17 , wherein the step of contacting the base resin with the peroxide compound comprises melt processing a mixture of the base resin and the peroxide compound in a twin screw extrusion system.
20. The process of claim 17 , wherein an amount of the peroxide compound is from 10 to 500 ppm by weight of peroxide groups, based on the weight of the base resin.