Tubular low density ethylene-based polymers with improved balance of extractables and melt elasticity
The invention provides an ethylene-based polymer comprising the following properties: a) weight fraction (w) of molecular weight above 5*10 6 g/mol, w>A−B*I2, where A=0.4 wt %, and B is 0.02 wt %/(dg/min), and w<C−B*I 2 %, where C=0.9 wt %; and b) G′>D−E*log(I2), where D=162 Pa and E=52 Pa/log(dg/min).
1. An ethylene-based polymer comprising the following properties:
a) weight fraction, as a percentage (w) of molecular weight above 5*10 6 g/mol, w>A−B*I2, where A=0.4 wt %, and B is 0.02 wt %/(dg/min), and w<C−B*I 2 %, where C=0.9 wt %;
b) G′ (at G″ equal to 500 Pa, 170° C.)>D−E*log(I2), where D=162 Pa and E=52 Pa/log(dg/min),
c) an Mw(abs) versus melt index (I 2 ) relationship: Mw(abs)≤A+B*log(I 2 ), where A=3.50*10 5 grams per mole (g/mole), and B=−1.20*10 5 (g/mole)/log(dg/min); and
d) n-hexane extractables <X wt % +Y*log(I 2 ), where X=2.3 wt % and Y=1.66 wt %/log(dg/min).
2. The ethylene-based polymer of claim 1 , wherein the polymer has a melt index (I 2 ) from 0.3 to 16 dg/min.
3. The ethylene-based polymer of claim 1 , wherein the polymer has a melt index (I 2 ) from 0.4 to 16 dg/min.
4. The ethylene-based polymer of claim 1 , wherein the polymer has a melt index (I 2 ) from 0.5 to 16 dg/min.
5. The polymer of claim 1 , in which the ethylene-based polymer has a melt index (I 2 )≥0.8 to ≤10 dg/min.
6. The polymer of claim 1 , in which the ethylene-based polymer has a density from 0.916 to 0.925 g/cc.
7. The polymer of claim 1 , in which the polymer has a n-hexane extractables level than or equal to 3.0 wt %.
8. The polymer of claim 1 , in which the n-hexane extractables are <X wt %+Y*log(I 2 ), where X=2.3 wt % and Y=1.66 wt %/log(dg/min) when the I 2 is 0.5 dg/min <I2<12 dg/min.
9. The polymer of claim 1 , in which the ethylene-based polymer has a weight fraction, as a percentage (w) of molecular weight above 5*10 6 g/mol, greater than 0.4 wt % and smaller than 0.7 wt %.
10. The polymer of claim 1 , in which the ethylene-based polymer comprises less than 30 mole parts per million (ppm) of a crosslinking agent or a comonomer with crosslinking capability, based on total moles of monomer units in the ethylene-base polymer.
11. The polymer of claim 1 , in which the ethylene-based polymer comprises less than 30 ppm of a comonomer containing multiple unsaturations or containing an acetylenic functionality.
12. The polymer of claim 1 , in which the ethylene-based polymer is prepared in a reactor configuration comprising at least one tubular reactor.
13. The polymer of claim 12 , in which the tubular reactor comprises at least three reaction zones.
14. The polymer of claim 12 , in which the tubular reactor comprises at least four reaction zones.
15. The polymer of claim 1 , in which the ethylene-based polymer is a polyethylene homopolymer.
16. The polymer of claim 15 , in which the ethylene-based polymer is LDPE.
17. A composition comprising the ethylene-based polymer of claim 1 .
18. A composition comprising the ethylene-based polymer of claim 16 .
19. An article comprising at least one component formed from the composition of claim 17 .
20. An article comprising at least one component formed from the composition of claim 18 .