Injection-molded articles comprising metallocene-catalyzed polyethylene resin

Patent metadata

Field	Value
Publication number	US-11208504-B2
Application number	US-201816629888-A
Country	US
Kind code	B2
Filing date	Jul 11, 2018
Priority date	Jul 11, 2017
Publication date	Dec 28, 2021
Grant date	Dec 28, 2021

Abstract

The present invention relates to an injection-molded 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 comprises:at least 40% to at most 50% 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 100.0 g/10 min as determined according to ISO 1133, condition D, at 190° C. and under a load of 2.16 kg; andwherein the at least one metallocene-catalyzed polyethylene resin has a density of at least 0.940 g/cm3 to at most 0.950 g/cm3 as measured on pellets according to ISO 1183 at 23° C.; a melt index MI2 of at least 1.4 g/10 min to at most 2.5 g/10 min as measured on pellets according to ISO 1133, condition D, at 190° C. and under a load of 2.16 kg.The present invention also relates to a process for preparing said injection-molded article, comprising the steps of a) providing at least one metallocene-catalyzed polyethylene resin as described herein; and b) injection-molding said polyethylene resin into an article.

First claim

The invention claimed is:

1. An injection-molded 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 comprises
at least 40% to at most 50% 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 100.0 g/10 min as determined according to ISO 1133:1997, condition D, at 190° C. and under a load of 2.16 kg; and
wherein the at least one metallocene-catalyzed polyethylene resin has a density of at least 0.940 g/cm 3 to at most 0.950 g/cm 3 as measured on pellets according to ISO 1183 at 23° C.; a melt index MI2 of at least 1.4 g/10 min to at most 2.5 g/10 min as measured on pellets according to ISO 1133:1997, condition D, at 190° C. and under a load of 2.16 kg.

2. The injection-molded article of claim 1 , wherein the at least one metallocene-catalyzed polyethylene resin has a molecular weight distribution M w /M n of at least 4.0 to at most 6.0, with M w being the weight-average molecular weight and M n being the number-average molecular weight.

3. The injection-molded article of claim 1 , wherein the at least one metallocene-catalyzed polyethylene resin has an HLMI of at least 50.0 g/10 min, as measured on pellets according to ISO 1133:1997 condition G at 190° C. and under a load of 21.6 kg.

4. The injection-molded article of claim 1 , wherein fraction A of the at least one metallocene-catalyzed polyethylene resin has a density at least 0.005 g/cm 3 higher than the density of the at least one metallocene-catalyzed polyethylene resin.

5. The injection-molded article of claim 1 , wherein fraction A of the at least one metallocene-catalyzed polyethylene resin has a density as measured on the fluff of at least 0.960 g/cm 3 , as measured according to ISO 1183 at 23° C.

6. The injection-molded article of claim 1 , wherein the at least one metallocene-catalyzed polyethylene resin has a multimodal molecular weight distribution, and wherein said at least one metallocene-catalyzed polyethylene resin has a bimodal molecular weight distribution.

7. The injection-molded article of claim 1 , wherein each fraction of said at least one metallocene-catalyzed polyethylene resin is prepared in different reactors of at least two reactors connected in series.

8. The injection-molded article of claim 1 , wherein the at least one metallocene-catalyzed polyethylene resin is prepared using a process comprising the steps of:
(a) feeding ethylene monomer, a diluent, at least one metallocene catalyst, optionally hydrogen, and optionally one or more olefin co-monomers into at least one first slurry loop reactor; polymerizing the ethylene monomer, and the optionally one or more olefin co-monomers, in the presence of the metallocene catalyst, and optional hydrogen, in said first slurry loop reactor to produce a first polyethylene fraction A; and
(b) feeding the first polyethylene fraction A to a second slurry loop reactor serially connected to the first slurry loop reactor, and in the second slurry loop reactor polymerizing ethylene, and optionally one or more olefin co-monomers, in the presence of the first polyethylene fraction, and optionally hydrogen, thereby producing the metallocene catalyzed-polyethylene resin.

9. The injection-molded article of claim 1 , wherein said at least one metallocene-catalyzed polyethylene resin is prepared using a process comprising the steps of:
(a) feeding ethylene monomer, a diluent, at least one metallocene catalyst, optionally hydrogen, and optionally one or more olefin co-monomers, into at least one first slurry loop reactor; polymerizing the ethylene monomer, in the presence of the metallocene catalyst, and optional hydrogen, in said first slurry loop reactor to produce a first polyethylene fraction A; and
(b) feeding the first polyethylene fraction A to a second slurry loop reactor serially connected to the first slurry loop reactor, and in the second slurry loop reactor polymerizing ethylene, and one or more olefin co-monomers, in the presence of the first polyethylene fraction, and optionally hydrogen, thereby producing the metallocene catalyzed-polyethylene resin.

10. The injection-molded article of claim 1 , wherein fraction A of said at least one metallocene-catalyzed polyethylene resin is an ethylene homopolymer and fraction B of said at least one metallocene-catalyzed polyethylene resin is an ethylene copolymer.

11. The injection-molded article of claim 1 , wherein said at least one metallocene-catalyzed polyethylene resin is prepared using a process comprising the steps of:
(a) feeding ethylene monomer, a diluent, at least one metallocene catalyst, one or more olefin co-monomers, and optionally hydrogen, into at least one first slurry loop reactor; polymerizing the ethylene monomer, in the presence of the metallocene catalyst, and optional hydrogen, in said first slurry loop reactor to produce a first polyethylene fraction; and
(b) feeding the first polyethylene fraction to a second slurry loop reactor serially connected to the first slurry loop reactor, and in the second slurry loop reactor polymerizing ethylene, and optionally one or more olefin co-monomers, in the presence of the first polyethylene fraction, and optionally hydrogen, thereby producing the metallocene catalyzed-polyethylene resin.

12. The injection-molded article of claim 1 , wherein the article is a tank, a drum, a container, a bin, a vat, a jerrycan, a can, a cistern, or slosh baffle, a pillar, a connector, or a cap or closure.

13. The injection-molded article of claim 1 , wherein the article is an automotive fuel tank.

14. The injection-molded article of claim 1 , wherein the article is a Selective Catalytic Reduction (SCR) tank.

15. A process for preparing an injection-molded article, comprising the steps of a) providing 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 comprises
at least 40% to at most 50% 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 100.0 g/10 min as determined according to ISO 1133:1997, condition D, at 190° C. and under a load of 2.16 kg; and
wherein the at least one metallocene-catalyzed polyethylene resin has a density of at least 0.940 g/cm 3 to at most 0.950 g/cm 3 as measured on pellets according to ISO 1183 at 23° C.; a melt index MI2 of at least 1.4 g/10 min to at most 2.5 g/10 min as measured on pellets according to ISO 1133:1997, condition D, at 190° C. and under a load of 2.16 kg; and b) injection-molding said polyethylene resin into an article.

Assignees

• Total Res & Technology Feluy

Inventors

• Vantomme Aurélien
• Gielens Jean-Léon
• Sigwald Armelle
• Willocq Christopher

Classifications

• C08F10/02

  Ethene · CPC title

• C08L2314/06

  Metallocene or single site catalysts · CPC title

• C08F2/001

  Multistage polymerisation processes characterised by a change in reactor conditions without deactivating the intermediate polymer (C08F295/00, C08F297/00 take precedence) · CPC title

• C08L2207/062

  HDPE · CPC title

• C08L2205/025

  containing two or more polymers of the same hierarchy C08L, and differing only in parameters such as density, comonomer content, molecular weight, structure · CPC title