Injection stretch blow moulded articles

Patent metadata

Field	Value
Publication number	US-9821504-B2
Application number	US-201213979101-A
Country	US
Kind code	B2
Filing date	Jan 10, 2012
Priority date	Jan 11, 2011
Publication date	Nov 21, 2017
Grant date	Nov 21, 2017

Abstract

This invention covers injection stretch blow molded articles prepared from polyethylene resin having a bimodal molecular weight distribution (MWD), defined by the ratio of the weight average molecular weight (Mw) to the number average molecular weight (Mn), of from 2 to 20, comprising two polyethylene fractions A and B, fraction A being substantially free of comonomer and having a lower weight average molecular weight and a higher density than fraction B, each fraction prepared in different reactors of two reactors connected in series in the presence of a metallocene-containing catalyst system.

First claim

The invention claimed is:

1. An injection stretch blow moulded article prepared from high density polyethylene (HDPE) resin comprising:
two polyethylene fractions comprising fraction A and fraction B, fraction A being substantially free of comonomer and having a lower weight average molecular weight and a higher density than fraction B, each fraction prepared in different reactors of two reactors connected in series in the presence of a metallocene-containing catalyst system;
wherein the metallocene is selected from at least one of the following formula (I) or (II):

wherein each R is the same or different and is selected from hydrogen or XR′ v in which X is chosen from carbon, silicon, germanium, oxygen or nitrogen, and each R′ is the same or different and is chosen from hydrogen or a hydrocarbyl of from 1 to 20 carbon atoms and v+1 is the valence of X;
wherein R″ is a structural bridge between the two indenyl or tetrahydrogenated indenyls to impart stereorigidity that comprises a C 1 -C 4 alkylene radical, a dialkyl germanium, silicon or siloxane, or an alkyl phosphine or amine radical;
wherein Q is a hydrocarbyl radical having from 1 to 20 carbon atoms or a halogen;
and wherein M is a transition metal Group 4 of the Periodic Table or vanadium;
wherein the HDPE resin has a bimodal molecular weight distribution (MWD), defined by the ratio of the weight average molecular weight (Mw) to the number average molecular weight (Mn), of from 2 to 20, a density, measured following the method of standard test ASTM 1505 at a temperature of 23° C., of from 0.950 to 0.965 g/cm 3 , and a melt index MI2, measured following the method of standard test ASTM D 1238 at a temperature of 190° C. and under a load of 2.16 kg, of from 0.5 to 5 g/10 min, and wherein the fraction B has a melt index MI2 of from 0.908 g/cm 3 to 0.938 g/cm 3 and a high load melt index HLMI, measured following the method of standard test ASTM D 1238 at a temperature of 190° C. and under a load of 21.6 kg, of from 4 to 45 g/10 min.

2. The injection stretch blow moulded article according to claim 1 wherein the metallocene comprises a bridged unsubstituted bis(tetrahydroindenyl).

3. The injection stretch blow moulded article according to claim 2 wherein the metallocene is selected from ethylene-bis(tetrahydroindenyl) zirconium dichloride and ethylene-bis(tetrahydroindenyl)zirconium difluoride.

4. The injection stretch blow moulded article according to claim 1 wherein the two reactors connected in series are a double loop reactor.

5. The injection stretch blow moulded article according to claim 1 wherein the HDPE resin has a melt index MI2 of 0.8 to 3 g/10 min, and a density of from 0.952 to 0.962 g/cm 3 .

6. The injection stretch blow moulded article according to claim 1 wherein the fraction A comprises a polyethylene obtained from a first reactor of the two reactors and the fraction B comprises a polyethylene obtained from a second reactor of the two reactors.

7. The injection stretch blow moulded article according to claim 1 wherein the fraction A has a melt index MI2, measured following the method of standard test ASTM D 1238 at a temperature of 190° C. and under a load of 2.16 kg, of from 10 to 1000 g/10 min, and a density, measured following the method of standard test ASTM 1505 at a temperature of 23° C., of from 0.953 to 0.980 g/cm 3 .

8. The injection stretch blow moulded article according to claim 1 wherein the HDPE resin exhibits a rheological horizontal activation energy at a frequency of 1 s −1 is more than 45 kJ/mol and at a frequency of 100 s −1 is less than 45 kJ/mol.

9. The injection stretch blow moulded article according to claim 8 wherein the rheological horizontal activation energy at a frequency of 1 s −1 is more than 50 kJ/mol and at a frequency of 100 s −1 is less than 40 kJ/mol.

10. The injection stretch blow moulded article according to claim 1 wherein the article is a bottle or a container.

11. The injection stretch blow moulded article according to claim 10 , wherein the container is a packaging for dairy products, food products, cosmetics, detergents or pharmaceutical products.

12. The injection stretch blow moulded article of claim 1 , wherein R is selected from hydrogen, methyl, ethyl, n-propyl, isopropyl, n-butyl and tert-butyl.

13. The injection stretch blow moulded article of claim 1 , wherein Q is chlorine or fluorine.

14. The injection stretch blow moulded article of claim 4 , wherein the double loop reactor is a liquid full double loop reactor.

15. The injection stretch blow moulded article of 5, wherein the HDPE resin has a density of from 0.954 to 0.962 g/cm 3

Assignees

• Boissiere Jean-Marie
• Vantomme Aurelien
• Belloir Pierre
• Van Sinoy Alain
• Total Res & Technology Feluy

Inventors

• Boissiere Jean-Marie
• Vantomme Aurelien
• Belloir Pierre
• Van Sinoy Alain

Classifications

• B29K2023/065

  HDPE, i.e. high density polyethylene · CPC title

• B29C49/06

  Injection blow-moulding · CPC title

• C08F4/65927

  two cyclopentadienyl rings being mutually bridged · CPC title

• B29K2023/0658

  characterised by its molecular weight · CPC title

• Y10T428/1352

  Polymer or resin containing [i.e., natural or synthetic] · CPC title