LDPE for use as a blend component in shrinkage film applications

摘要

An ethylene-based polymer characterized as having a density from about 0.9 to about 0.94 grams per cubic centimeter, a molecular weight distribution (Mw/Mn) from about 4 to about 10, a melt index (I2) from about 0.05 to about 2 grams per 10 minutes, a gpcBR value greater than 0.05 as determined by a gpcBR Branching Index and a Y value greater than 0.4 is disclosed. This ethylene-based polymer is especially useful for blending with other polymers such as LLDPE. When converting the blends into film, especially shrink film, the film shows good optics, good shrink tension, high stiffness, high tensile modulus, and tensile strength. When this resin is blended at with a LLDPE on a blown film line, improvements are seen in haze, gloss, clarity, and MD and CD tear as compared to a comparative LDPE.

主权项

1. An ethylene-based polymer characterized as having a density from about 0.9 to about 0.94 grams per cubic centimeter, a molecular weight distribution (Mw/Mn) from about 4 to about 10, a melt index (I2) from about 0.05 to less than 0.8 grams per 10 minutes, a gpcBR value greater than 0.05, as determined by a gpcBR Branching Index, and a GPC-LS characterization Y value greater than about 0.4, wherein the GPC-LS characterization Y value is determined according to the following formula;
Y=Abs(A/B/(Abs(x)+0.05)) wherein A is the area between (a) a straight line between a first intercept point and a second intercept point at the two logarithmic cc-GPC molecular weight values, located on the concentration-normalized LS chromatogram curve, and (b) the concentration-normalized LS chromatogram curve between the two logarithmic cc-GPC molecular weight values, and wherein B is the area under the concentration-normalized LS chromatogram curve between the two logarithmic cc-GPC molecular weight values; and wherein x is determined according to the following formula:x=LSresponse(Point⁢⁢2,CN)-LSresponse(Point⁢⁢1,CN)LSresponse(Point⁢⁢2,CN)log⁢⁢MW(Point⁢⁢2,ccGPC)-log⁢⁢MW(Point⁢⁢1,ccGPC) wherein LSresponse(Point2,CN) is the concentration-normalized (CN) LS response value for Intercept 2, corresponding to logarithmic cc-GPC molecular weight value of 6.0607, LSresponse(Point1,CN) is the concentration-normalized (CN) LS response value for Intercept 1, corresponding to the logarithmic cc-GPC molecular weight value of 5.3010, and log MW(Point2,ccGPC) is the logarithmic cc-GPC molecular weight for Intercept 2, corresponding to the logarithmic cc-GPC molecular weight value 6.0607, log MW(Point1,ccGPC) is the logarithmic cc-GPC molecular weight for Intercept 1 corresponding to the logarithmic cc-GPC molecular weight value of 5.3010; and wherein Abs( ) is the mathematical absolute value function, andwherein the ethylene-based polymer is a homopolymer.