Polymer molding compositions
View Patent ↗The invention relates to formulated compositions which can be easily formed into bottle caps, without the need for a liner, while still maintaining pressure requirements, such as for carbonated beverages. The compositions may include an ethylene polymer having a density in the range of from about 0.947 to 0.962 g/cm 3 , a melt index of from about 1 to about 10 g/10 min., and another ethylene polymer having a density in the range of from about 0.912 to 0.932 g/cm 3 , a melt index of from about 0.25 to about 6 g/10 min., wherein the two ethylene polymers have a density difference of equal to or greater than 0.03 g/cm 3 . In other cases, the composition may include a single component resin with a density in the 0.935-0.955 g/cm 3 range with a melt index in the range of 0.3-1.2 g/10 minutes, and wherein the resin comprises a polyethylene polymer.
1. A polyethylene composition consisting essentially of:
a single component polyethylene polymer having a density in the range of 0.935-0.955 g/cm 3 and a melt index in the range of 0.3-1.2 g/10 minutes, wherein said single component polyethylene polymer comprises at least from 0.05 to 5 percent per weight of 1-hexene based on total weight of said single component polyethylene polymer; and
optionally from 0 to 6 weight percent by weight of one or more additives selected from the group consisting of color enhancers, lubricants, fillers, pigments, antioxidants, and processing aids;
wherein said polyethylene composition has an Environmental Stress Crack Resistance according to ASTM D-1693 procedure B with 100% Branched Octylphenoxy Poly(Ethyleneoxy)Ethanol, exceeding 80 hours.
2. The composition of claim 1 , wherein the melt index range is from 0.4-1.1 g/10 minutes.
3. The composition of claim 1 , wherein the melt index range is from 0.5-1.0 g/10 minutes.
4. The composition of claim 1 , wherein the density range is from about 0.938 to 0.952 g/cm 3 .
5. The composition of claim 1 , wherein the density range is from about 0.942 to 0.950 g/cm 3 .
6. The composition of claim 1 , wherein the at least one additive is present in about 0.01 to 3 weight percent.
7. The composition of claim 1 , wherein the at least one additive is present in about 0.015 to 0.5 weight percent.
8. A closure comprising the composition of claim 1 .
9. The composition of claim 1 , wherein the polyethylene polymer composition is characterized as having a 1-hexene content of from about 0.5 weight percent to about 4 weight percent.
10. The composition of claim 1 , wherein the polyethylene polymer composition is characterized as having a soluble fraction greater than about 1.75% (as determined via CRYSTAF).
11. The composition of claim 1 , wherein said composition has an Environmental Stress Crack Resistance according to ASTM D-1693 procedure B with 100% Branched Octylphenoxy Poly(Ethyleneoxy)Ethanol exceeding 150 hours.
12. A composition of claim 1 where in the Mw/Mn is between 3 and 20.
13. A method of forming a closure device comprising forming the composition of claim 1 into a closure device.