Elastomeric resin compositions with improved resistance to draw resonance
View Patent ↗This invention relates to polyolefin compositions. In particular, the invention pertains to elastic polymer compositions that can be more easily processed on cast film lines, extrusion lamination or coating lines due to improved resistance to draw resonance. The compositions of the present invention comprise an elastomeric polyolefin resin and a high pressure low density type resin. The preferred compositions of the present invention comprise from 88 to 99 percent elastomer or plastomer and from 1 to 12 percent by weight of a high pressure low density type resin.
1. A composition comprising:
a. about 88 to about 99 percent by weight of the composition of a linear and/or substantially linear ethylene/alpha olefin copolymer plastomer and/or elastomer having a density of less than about 0.885 g/cm 3 and a melt index (I 2 ) of less than about 20 g/10 min; and
b. from about 1 to about 12 percent by weight of the composition of a high pressure low density resin
wherein the heat of melting of the composition (measured by integrating the area under the melting endotherm of a differential scanning calorimetry (DSC) curve from the beginning of melting to the end of melting by using a linear baseline) is less than about 60 J/g; and wherein the partial area above 80° C. for the composition is less than about 25% of the total heat of melting; and wherein the cumulative detector fraction (CDF) for the composition having molecular weights greater than 1,150,000 is in a range of from greater than about 0.02 to about 0.167, where the CDF of the LALLS chromatogram (CDFLS) is calculated based on its baseline-subtracted peak height (H) from high to low molecular weight (low to high retention volume (RV)) at each data slice (i) according to the following equation:
CDF
i
=
∑
j
=
LowestRVindex
i
H
j
∑
j
=
LowestRVindex
HighestRVindex
H
j
where i is between the LowestRVindex and the HighestRVindex.
2. The composition of claim 1 wherein the first component is selected from the group comprising copolymers of ethylene with at least one other alpha olefin (C 3 -C 22 ).
3. The composition of claim 1 wherein first component has a density of less than about 0.88 g/cm 3 .
4. The composition of claim 1 wherein first component has a density of less than about 0.875 g/cm 3 .
5. The composition of claim 1 wherein first component has a melt index (I 2 ) of less than about 15 g/10 min.
6. The composition of claim 1 wherein first component has a melt index (I 2 ) of less than about 12 g/10 min.
7. The composition of claim 1 wherein the partial area above 80° C. is greater than about 4 percent and less than about 20 percent of the total heat of melting.
8. The composition of claim 1 wherein the partial area above 80° C. is greater than about 7 percent and less than about 17 percent of the total heat of melting.
9. The composition of claim 1 wherein the CDF is greater than about 0.03 and less than about 0.12.
10. The composition of claim 1 wherein the CDF is greater than about 0.04 and less than about 0.09.