초록 ▼

An LLDPE produced using a single site catalyst, e.g., an LLDPE produced using a metallocene (m-LLDPE), is preferably used in injection moulding of food packaging material, especially closures for food containers. Such materials have been found to exhibit low levels of migration, typically less than

An LLDPE produced using a single site catalyst, e.g., an LLDPE produced using a metallocene (m-LLDPE), is preferably used in injection moulding of food packaging material, especially closures for food containers. Such materials have been found to exhibit low levels of migration, typically less than 40 mg/dm 2 , e.g., less than 5 mg/dm 2 , and are particularly suitable for use in packaging foods having a high fat content.

대표청구항 ▼

1. A method for producing a food packaging material which comprises:injecting a linear low density polyethylene (LLDPE) produced using a single site catalyst into a mould wherein said LLDPE exhibits the following characteristics:an MFR 2.16 of from about 20 to 100;a density of from about 910 to 930

1. A method for producing a food packaging material which comprises:injecting a linear low density polyethylene (LLDPE) produced using a single site catalyst into a mould wherein said LLDPE exhibits the following characteristics:an MFR 2.16 of from about 20 to 100;a density of from about 910 to 930 ka/m3;a weight average molecular weight (Mw) of from about 20 to 100 kD;a number average molecular weight (Mn) of from about 5 to 30 kD; anda ratio of the weight average molecular weight to the number average molecular weight (MWD) is about 3 to 6. 2. The method claimed in claim 1 wherein said LLDPE is a metallocene LLDPE. 3. The method claimed in claim 1 wherein food packaging material is a closure for a food container. 4. An injection moulded article formed from an LLDPE produced using a single site catalyst wherein said LLDPE exhibits the following characteristics:an MFR 2.16 of from about 20 to 100;a density of from about 910 to 930 kg/m3;a weight average molecular weight (Mw) of from about 20 to 100 kD;a number average molecular weight (Mn) of from about 5 to 30 kD; anda ratio of the weight average molecular weight to the number average molecular weight (MWD) is about 3 to 6. 5. An article as claimed in claim 4 formed from a metallocene LLDPE. 6. An article as claimed in claim 4 wherein said injection moulded article is a closure. 7. An article as claimed in claim 6 wherein said closure is for a food container. 8. An LLDPE suitable for use in injection moulding, said LLDPE comprising a migration level of less than 10 mg/dm2 and having an MFR 2.16 of 20 to 100. 9. The LLDPE as claimed in claim 8 wherein said LLDPE is a metallocene LLDPE. 10. The LLDPE as claimed in claim 8 wherein said LLDPE exhibits the following characteristics:an MFR 2.16 of from about 20 to 100;a density of from about 910 to 930 kg/m3;Mw (weight average molecular weight) of from 20 to 100 kD;a number average molecular weight (Mn) of from about 5 to 30 kD; anda ratio of the weight average molecular weight to the number average molecular weight (MWD) of about 3 to 10. 11. A method for producing an article which comprises:injecting a linear low density polyethylene (LLDPE) into a mould, wherein said LLDPE has a migration level of less than 10 mg/dm2 and an MFR 2.16 of 20 to 100. 12. The method claimed in claim 11 wherein said LLDPE is a metallocene LLDPE. 13. The method claimed in claim 11 wherein said article is a closure for a container. 14. The method claimed in claim 11 wherein said LLDPE exhibits the following characteristics:an MFR 2.16 of from about 20 to 100;a density of from about 910 to 930 kg/m3;a weight average molecular weight (Mw) of from about 20 to 100 kD;a number average molecular weight (Mn) of from about 5 to 30 kD; anda ratio of the weight average molecular weight to the number average molecular weight (MWD) of about 3 to 10. 15. A closure for a food container, which closure is formed from an LLDPE wherein said LLDPE exhibits the following characteristics:an MFR 2.16 of from about 20 to 100;a density of from about 910 to 930 kg/m3;a weight average molecular weight (Mw) of from about 20 to 100 kD;a number average molecular weight (Mn) of from about 5 to 30 kD: anda ratio of the weight average molecular weight to the number average molecular weight (MWD) is about 3 to 6. 16. The closure as claimed in claim 15 wherein said LLDPE is a metallocene LLDPE. 17. The closure as claimed in claim 15 which is farmed from an LLDPE having a migration level of less than 40 mg/dm2. 18. The closure as claimed in claim 15 which is associated with a plastic, glass or metal container. 19. The closure as claimed in claim 18 wherein said plastic is polypropylene. 20. The LLDPE according to claim 8 wherein said migration level is less than 5 mg/dm2. 21. The LLDPE according to claim 10 wherein said ratio of the weight average molecular weight to the number average molecular weight is about 3 to 6. 22. The method according to claim 11 wherein said migration l evel is less than 5 mg/dm2. 23. The method according to claim 14 wherein said ratio of the weight average molecular weight to the number average molecular weight is about 3 to 6. 24. The closure as claimed in claim 17 wherein said migration level of less than 10 mg/dm2. 25. The closure as claimed in claim 24 wherein said LLDPE has an MFR 2.16 of 20 to 100.