High-density polyethylene compositions, method of making the same, injection molded articles made therefrom, and method of making such articles

A high-density polyethylene composition that is formulated to be injection molded into an injection-molded bottle cap closure comprising a skirt that axially extends from the periphery of a base, and internal screw threads for securing the cap to a container, and wherein the injection-molded bottle cap closure has improved shrinkage behavior, the composition comprising:

• a first component, said first component being a high molecular weight ethylene alpha-olefin copolymer having a density in the range of 0.920 to 0.946 g/cm3, and a melt index (I21.6) in the range of 1 to 15 g/10 minutes;
• and
• a second component, said second component being a low molecular weight ethylene polymer having a density in the range of 0.965 to 0.980 g/cm3, and a melt index (I2) in the range of 30 to 1500 g/10 minutes;
• wherein said high-density polyethylene composition having a melt index (I2) of at least 1 g/10 minutes, a density in the range of 0.950 to 0.960 g/cm3;
• wherein said high-density polyethylene composition has a 1% secant modulus in psi of equal or greater to the following relationship:
• [(7,492,165*density (g/cm3)) -6,975,000]psi/(g/cm3));
• wherein said high-density polyethylene composition has a molecular weight distribution (Mw/Mn) from 5 to 13;
• and
• wherein said high-density polyethylene composition has a standard deviation of flow direction shrinkage of less than 7 percent across different colors.