Patent EA-000908-B1 (EA)
Title: Radiation tolerant polypropylene and its useful articles
Inventor: KOZIMOR RENEE A
IPC: C08K5/41
Filed: 1996-08-29
Abstract: 1. An article of manufacture suitable for radiation sterilization of itself or its contents or which has been exposed to radiation sufficient for such sterilization, comprising a blend of from 50 to 99 wt% polypropylene with from 1 to 50 wt% polyethylene, said polyethylene having a MWD between 1 and 4, and a CDBI greater than 45%. 2. The article of claim 1 wherein said article comprises a film, packaging material or a medical device. 3. The article of claim 2, wherein said packaging material comprises packaging material for medical devices or drugs, unit-dose or other blister or bubble packs; wrapping material or containers for food preserved by irradiation; or packaging materials for stored liquid. 4. The article of claim 2, wherein said packaging material further comprises self supporting multilayered structure wherein said multilayered structure comprises metal foil, cellulosic material or plastic film. 5. The article of claim 2, wherein said medical device is formed by extrusion, blowing, lamination, blow molding, transfer molding, injection molding, in the process of producing monoaxial-oriented fibrous plastic by pultrusion, protrusion, draw reduction, rotational molding, spinbonding, melt spinning or melt blowing. 6. The article of any of the preceding claims, wherein said article has been subjected to radiation in an amount up to about 10 MRad. 7. The article of any of the preceding claims, wherein said polypropylene is a random copolymer comprising propylene and at least one other alpha-olefin. 8. The article of any of the preceding claims, wherein said polypropylene is a homopolymer. 9. The article of any of the preceding claims, wherein said polypropylene has a weight average molecular weight of from 10,000 to 400,000, preferably from 40,000 to 300,000, more preferably from 50,000 to 200,000, and a MWD of from 1 to 9, preferably from 1 to 6, more preferably from 1 to 4. 10. The article of any of the preceding claims, wherein said polyethylene has a density of from 0.865 g/cc to 0.920g/cc, preferably from 0.880 g/cc to 0.915 g/cc, more preferably from 0.895 g/cc to 0.910 g/cc, and a melt index of from 2 to 11 dg/min., preferably from 3 to 9 dg/min. 11. An article, prepared for radiation sterilization of itself or its contents or which has been exposed to radiation sufficient for such sterilization, comprising: a) from 50 to 99 wt% polypropylene homopolymer; b) from 1 to 50 wt%, preferably 5 to 15 wt% polyethylene produced by single-site catalysis; and c) 0.01 to 0.5 wt%, preferably from 0.02 to 0.2 wt%, more preferably from 0.03 to 0.15 wt% hindered amine stabilizer; and optionally d) 1 wt% of a thiopropionate secondary antioxidant; e) up to 0.5 wt%, preferably 0.02 to 0.2 wt%, more preferably from 0.03 to 0.15 wt% of a phosphite secondary antioxidant; f) up to 0.5 wt%, preferably from 0.05 to 0.15 wt%, more preferably from 0.05 to 0.1 wt% acid neutralizing scavenger; g) up to 0.5 wt%, preferably from 0.1 to 0.4 wt% clarifying nucleator; or h) combinations thereof. 12. The article of claim 11, wherein said article comprises packaging material. 13. The article of claim 11, wherein said article comprises a medical device. 14. A process for producing a sterilized article, comprising the steps of blending from about 50 to about 99 wt% polypropylene with from 1 to 50 wt% polyethylene, wherein said polyethylene is produced using a single site catalyst, producing an article from said blend, and subjecting said article to radiation, preferably in an amount up to 10 MRad.