Polymer composition for caps and closures

Patent metadata

Field	Value
Publication number	US-9976017-B2
Application number	US-201515109849-A
Country	US
Kind code	B2
Filing date	Jan 5, 2015
Priority date	Jan 6, 2014
Publication date	May 22, 2018
Grant date	May 22, 2018

Abstract

Polyethylene composition having a density of 950-960 kg/m3, a SHI(1,100) of 4-12, a melt index MI2 between 0.2 and 2 g/10 min, and a relationship between spiral flow ‘SF’ (measured in mm at 250° C./1000 bar/100 mm/s) and ESCR ‘E’ (measured in hours) of E>200−SF. The composition contains 48-62 wt % of an ethylene polymer (A) and 38-52 wt % of an ethylene copolymer (B). Copolymer (B) has a higher weight average molecular weight than polymer (A), and both of fractions (A) and (B) have a reverse comonomer distribution such that comonomer content increases with increasing molecular weight in the individual fraction.

First claim

The invention claimed is:

1. Polyethylene composition having a density of 950-960 kg/m 3 , a SHI (1,100) of 4-12, a melt index MI 2 between 0.2 and 2 g/10 min, and a relationship between spiral flow ‘SF’ (measured in mm at 250° C./1000 bar/100 mm/s) and ESCR ‘E’ (measured in hours) of E>200−SF, wherein the composition comprises 48-62 wt % of an ethylene polymer (A) and 38-52 wt % of an ethylene copolymer (B), copolymer (B) having a higher weight average molecular weight than copolymer (A), and both of fractions (A) and (B) have a reverse comonomer distribution such that comonomer content increases with increasing molecular weight in the individual fraction.

2. Composition according to claim 1 , wherein the relationship between spiral flow ‘SF’ (measured in mm at 250° C./1000 bar/100 mm/s) and ESCR ‘E’ (measured in hours) is E>370−2SF.

3. Polyethylene composition having a density of 950-960 kg/m 3 , of SHI (1,100) of 4-12, a melt index MI2 between 0.2 and 2 g/10 min, and a relationship between spiral flow ‘SF’ (measured in mm at 250° C./1000 bar/100 mm/s), ESCR ‘E’ (measured in hours) and melt index ‘MI2’ (measured in g/10 min according to ISO 1133 at 190° C. at load of 2.16 kg) of E>(9800−36SF−1000MI2)/60.

4. Composition according to claim 3 , wherein the relationship between spiral flow ‘SF’, ESCR ‘E’ and melt index ‘MI2’ is E>(11000−36SF−1000MI2)/60.

5. Composition according to claim 1 , which has a SHI (1,100) between 4 and 10.

6. Composition according to claim 1 , which has a molecular weight distribution (Mw/Mn) (measured by GPC analysis) between 5 and 13.

7. Composition according to claim 1 , which has a relationship between spiral flow ‘SF’ (measured in mm at 250° C./1000 bars/100 mm/s) and solubles ‘S’ (measured in g/kg) of S<0.1SF.

8. Composition according to claim 1 , which comprises 50-60 wt % of ethylene polymer (A) and 40-50 wt % of ethylene copolymer (B).

9. Composition according to claim 1 , wherein ethylene polymer (A) is a copolymer, and has a density between 969 and 974 kg/m3 and a MI2 of from 10 to 800 g/10 min.

10. Composition according to claim 1 , which has a density between 950 to 954 kg/m3 and an MI2 of between 1 and 2 g/10 min.

11. Composition according to claim 1 , which has a density between 954 to 960 kg/m3 and an MI2 of between 0.1 and 1 g/10 min.

12. Composition according to claim 1 , which has a density between 950 to 954 kg/m3 and an MI2 of between 1 and 2 g/10 min, wherein the density of copolymer (B) is between 919 and 936 kg/m3 and the HLMI of copolymer (B) is from 3 to 6 g/10 min.

13. Composition according to claim 1 , which has a density between 954 to 960 kg/m3 and an MI2 of between 0.1 and 1 g/10 min, wherein the density of copolymer (B) is between 929 and 947 kg/m3 the HLMI of the copolymer (B) is from 0.2 to 2 g/10 min.

14. Composition according to claim 3 , which has a SHI (1,100) between 4 and 10.

15. Composition according to claim 3 , which has a molecular weight distribution (Mw/Mn) (measured by GPC analysis) between 5 and 13.

16. Composition according to claim 3 , which has a relationship between spiral flow ‘SF’ (measured in mm at 250° C./1000 bars/100 mm/s) and solubles ‘S’ (measured in g/kg) of S<0.1SF.

17. Composition according to claim 3 , which comprises 48-62 wt % of an ethylene polymer (A) and 38-52 wt % of an ethylene copolymer (B), copolymer (B) having a higher weight average molecular weight Mw than polymer (A).

18. Composition according to claim 3 , wherein ethylene polymer (A) is a copolymer, and has a density between 969 and 974 kg/m3 and a MI2 of from 10 to 800 g/10 min.

19. Composition according to claim 3 , which has a density between 950 to 954 kg/m3 and an MI2 of between 1 and 2 g/10 min.

20. Composition according to claim 3 , which has a density between 954 to 960 kg/m3 and an MI2 of between 0.1 and 1 g/10 min.

21. Composition according to claim 3 , which has a density between 950 to 954 kg/m3 and an MI2 of between 1 and 2 g/10 min, wherein the density of copolymer (B) is between 919 and 936 kg/m3 and the HLMI of copolymer (B) is from 3 to 6 g/10 min.

22. Composition according to claim 3 , which has a density between 954 to 960 kg/m3 and an MI2 of between 0.1 and 1 g/10 min, wherein the density of copolymer (B) is between 929 and 947 kg/m3 the HLMI of the copolymer (B) is from 0.2 to 2 g/10 min.

23. Composition according to claim 2 , wherein the relationship between spiral flow ‘SF’ (measured in mm at 250° C./1000 bar/100 mm/s) and ESCR ‘E’ (measured in hours) is E>540−3SF.

24. Composition according to claim 4 , wherein the relationship between spiral flow ‘SF’, ESCR ‘E’ and melt index ‘MI2’ is E>(12000−36SF−1000MI2)/60.

25. Composition according to claim 5 , which has a SHI (1,100) between 4 and 8.

26. Composition according to claim 7 , which has a relationship between spiral flow ‘SF’ (measured in mm at 250° C./1000 bars/100 mm/s) and solubles ‘S’ (measured in g/kg) of S<0.1SF−2.5.

27. Composition according to claim 26 , which has a relationship between spiral flow ‘SF’ (measured in mm at 250° C./1000 bars/100 mm/s) and solubles ‘S’ (measured in g/kg) of S<0.1SF−5.

Assignees

• Ineos Europe Ag

Inventors

• Koch Benoit
• Moineau Christophe

Classifications

• C08F2500/13

  Environmental stress cracking resistance · CPC title

• C08F4/65916

  supported on a carrier, e.g. silica, MgCl2, polymer · CPC title

• B65D39/00

  Closures arranged within necks or pouring openings or in discharge apertures, e.g. stoppers (lids or covers B65D43/00) · CPC title

• C08F2500/07

  High density, i.e. > 0.95 g/cm3 · CPC title

• C08F2500/01

  High molecular weight, e.g. >800,000 Da. · CPC title