Bi- or multimodal polyethylene with enhanced rheological properties
AssigneeBorealis AG
InventorGirish Suresh GALGALI
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Abstract
New bi- or multimodal polyethylene terpolymer made with a metallocene catalyst and having a narrow molecular weight distribution as well as enhanced rheological properties, i.e. higher relaxation spectrum index (RSI), respectively normalized relaxation spectrum index (nRSI) to the use of the bi- or multimodal polyethylene terpolymer for film applications and to a film comprising the new bi- or multimodal polyethylene terpolymer.
Claims10
A bi- or multimodal polyethylene terpolymer comprising a terpolymer of ethylene and two different comonomers, wherein the two different comonomers are selected from alpha olefins having from 4 to 10 carbon atoms and wherein the bi- or multimodal polyethylene terpolymer is produced with a metallocene catalyst, wherein the bi- or multimodal polyethylene terpolymer has
- (a) an MFR2 of 2.0 to 5.0 g/10 min (according to ISO 1133 at 190° C. under 2.16 kg load),
- (b) an MWD (Mw/Mn) of 5 or less,
- (c) a density of from 915 to 930 kg/m3 (according to ISO 1183),
- (d) a Relaxation Spectrum Index (RSI) (determined as defined in the description under Experimental part using frequency sweep at 190° C.) of at least 3.0,
- (e) a normalized Relaxation Spectrum Index (nRSI) calculated from RSI/MFR2 of at least 1.00,
- (f) a calculated Relaxation Spectrum Index (cRSI) defined as RSI*MFR2*MWD of at least 36,
- and wherein the bi- or multimodal polyethylene terpolymer comprises
- (i) a first ethylene polymer component having an MFR2 of from 50 g/10 min to 100 g/10 min (according to ISO 1133 at 190° C. under 2.16 kg load), and
- (ii) a second ethylene polymer component having an MFR2 of from 0.5 to 10.0 g/10 min (according to ISO 1133 at 190° C. under 2.16 kg load).
Dependencies are inferred from the claim text.