Rotomolded articles comprising metallocene-catalyzed polyethylene resin

Patent metadata

Field	Value
Publication number	US-10550251-B2
Application number	US-201515525669-A
Country	US
Kind code	B2
Filing date	Nov 10, 2015
Priority date	Nov 13, 2014
Publication date	Feb 4, 2020
Grant date	Feb 4, 2020

Abstract

The present invention also relates to a process for preparing said rotomolded article.

First claim

The invention claimed is:

1. A rotomolded article, comprising at least one metallocene-catalyzed polyethylene resin comprising at least two metallocene-catalyzed polyethylene fractions A and B, wherein the at least one metallocene-catalyzed polyethylene resin has a bimodal molecular weight distribution and comprises:
at least 25% to at most 55% by weight of polyethylene fraction A based on the total weight of the at least one metallocene-catalyzed polyethylene resin, wherein fraction A has a melt index MI2 of at least 25.0 g/10 min as determined according to ISO 1133, condition D, at 190° C. and under a load of 2.16 kg, and a density at least 0.005 g/cm 3 higher than the density of the at least one metallocene-catalyzed polyethylene resin; and
wherein the at least one metallocene-catalyzed polyethylene resin has a density of at least 0.938 g/cm 3 to at most 0.950 g/cm 3 as measured according to ASTM D-1505 at 23° C.; a melt index MI2 of at least 1.0 g/10 min to at most 25.0 g/10 min as determined according to ISO 1133, condition D, at 190° C. and under a load of 2.16 kg, wherein each fraction of said at least one metallocene-catalyzed polyethylene resign is prepared in at least two slurry loop reactors connected in series.

2. The rotomolded article according to claim 1 , wherein the at least one metallocene-catalyzed polyethylene resin has a molecular weight distribution M w /M n of at least 2.0 to at most 5.0, with M w being the weight-average molecular weight and M n being the number-average molecular weight.

3. The rotomolded article according to claim 1 , wherein fraction A of the at least one metallocene-catalyzed polyethylene resin has a density at least 0.010 g/cm 3 higher than the density of the at least one metallocene-catalyzed resin.

4. The rotomolded article according to claim 1 , wherein polyethylene fraction A of the at least one metallocene-catalyzed polyethylene resin has a density as measured on a fluff of at least 0.950 g/cm 3 .

5. The rotomolded article according to claim 1 , wherein polyethylene fraction A of the at least one metallocene-catalyzed polyethylene resin has a melt index MI2 as measured on a fluff of at least 30.0 g/10 min.

6. The rotomolded article according to claim 1 , wherein the at least one metallocene-catalyzed polyethylene resin has a multimodal molecular weight distribution.

7. The rotomolded article according to claim 1 , wherein said at least one metallocene-catalyzed polyethylene resin is compounded with at least one additive.

8. The rotomolded article according to claim 1 , wherein said at least one metallocene-catalyzed polyethylene resin is compounded with at least one ionomer.

9. The rotomolded article according to claim 1 , wherein said at least one metallocene-catalyzed polyethylene resin is compounded with 0.1% to 20% by weight of at least one ionomer relative to the total weight of the compounded resin.

10. The rotomolded article according to claim 1 , wherein the article is a tank, a drum, a container, a bin, a vat, a jerrycan, a can, a cistern, a bottle, boat or part thereof, float, buoy, structural part.

11. The rotomolded article according to claim 1 , wherein the Temperature Rising Elution Fractionation (TREF) distribution curve of the at least one metallocene-catalyzed polyethylene resin comprises at least one peak appearing at a temperature of at least 97° C. to at most 105° C. and having an area under the curve of at least 5.0% to at most 25.0%; as determined using a crystallization rate of −0.5° C./min from 95° C. to 35° C., and column load volume of 1.90 ml.

12. The rotomolded article according to claim 11 , wherein the Temperature Rising Elution Fractionation (TREF) distribution curve of the at least one metallocene-catalyzed polyethylene resin further comprises two more peaks having the following features:
peak 1 appearing at a temperature of at least 87.0° C. to at most 93.0° C. and having an area under the curve of at least 25.0% to at most 50.0%;
peak 2 appearing at a temperature of at least 94.0° C. to at most 98.0° C. and having an area under the curve of at least 35.0% to at most 60.0%.

13. A rotomolding process for preparing a rotomolded article according to claim 1 , comprising the steps of a) providing at least one metallocene-catalyzed polyethylene resin having a bimodal molecular weight distribution and comprising at least two polyethylene fractions A and B, wherein the at least one metallocene-catalyzed polyethylene resin comprises: at least 25% to at most 55% by weight of polyethylene fraction A based on the total weight of the at least one metallocene-catalyzed polyethylene resin, wherein fraction A has a melt index MI2 of at least 25.0 g/10 min as determined according to ISO 1133, condition D, at 190° C. and under a load of 2.16 kg, and a density at least 0.005 g/cm 3 higher than the density of the at least one metallocene-catalyzed polyethylene resin; wherein the at least one metallocene-catalyzed polyethylene resin has a density of at least 0.938 g/cm 3 to at most 0.950 g/cm 3 as measured according to ASTM D-1505 at 23° C.; a melt index MI2 of at least 1.0 g/10 min to at most 25.0 g/10 min as determined according to ISO 1133, condition D, at 190° C. and under a load of 2.16 kg, wherein each fraction of said at least one metallocene-catalyzed polyethylene is prepared in at least two slurry loop reactors connected in series; and b) rotomolding said polyethylene resin into an article.

Assignees

• Total Res & Technology Feluy

Inventors

• Vantomme Aurélien
• Maziers Eric
• Willocq Christopher

Classifications

• B29L2031/7172

  Fuel tanks, jerry cans · CPC title

• B29L2031/7154

  Barrels, drums, tuns, vats · CPC title

• C08L2314/06

  Metallocene or single site catalysts · CPC title

• B29C41/003

  characterised by the choice of material · CPC title

• C08L23/0815 Primary

  with aliphatic 1-olefins containing one carbon-to-carbon double bond · CPC title