Polyolefin composition

Abstract

The invention relates to a polyolefin composition comprising A. at least a homopolymer or copolymer of ethylene or propylene and B. cholestanyl ferulate. The composition can be used in the production of articles such as a pipe, cap and closure, film, food contact packaging, biomedical article, health care article and pharmaceutical article.

Claims

1. A polyolefin composition comprising: A. at least a homopolymer or copolymer of ethylene or propylene and B. cholestanyl ferulate.

2. The composition according to claim 1 characterised in that the homo- or copolymer is high density polyethylene, multimodal high density polyethylene, low density polyethylene, linear low density polyethylene or polypropylene.

3. The composition according to claim 2 characterised in that the homo- or copolymer is bimodal polyethylene.

4. An article produced with the polyolefin composition according to claim 1.

5. The article according to claim 4 wherein the article is a pipe, cap and closure, film, food contact packaging, biomedical article, health care article or pharmaceutical article.

6. The article according to claim 5 wherein the article is a pipe and is characterised in that the composition comprises a phenolic compound and organic phosphite and/or phosphonite.

7. The composition according to claim 2 characterised in that the homo- or copolymer is high density polyethylene.

8. The composition according to claim 2 characterised in that the homo- or copolymer is multimodal high density polyethylene.

9. The composition according to claim 2 characterised in that the homo- or copolymer is low density polyethylene.

10. The composition according to claim 2 characterised in that the homo- or copolymer is linear low density polyethylene or polypropylene.

11. An article produced with the polyolefin composition according to claim 2.

12. The article according to claim 11 wherein the article is a pipe, cap and closure, film, food contact packaging, biomedical article, health care article or pharmaceutical article.

13. The article according to claim 12 wherein the article is a pipe and is characterised in that the composition comprises a phenolic compound and organic phosphite and/or phosphonite.

14. An article produced with the polyolefin composition according to claim 3.

15. The article according to claim 14 wherein the article is a pipe, cap and closure, film, food contact packaging, biomedical article, health care article or pharmaceutical article.

16. The article according to claim 15 wherein the article is a pipe and is characterised in that the composition comprises a phenolic compound and organic phosphite and/or phosphonite.

Description

EXAMPLES

(1) The following compounds were used: High density polyethylene (HDPE) (SABIC® HDPE M80064) (unstabilized or reactor powder) Cholestanyl ferulate (3-O-(trans-4-feruloyl)-β-cholestanol) (purchased from United States Department of Agriculture Agricultural Research Service, Peoria, Ill.) α-tocopherol (Vitamin E purchased from BASF; Irganox® E201) 775 ppm calcium stearate was present in C2 and I1

(2) Table 1 shows the compositions which were added to HDPE.

(3) TABLE-US-00001 TABLE 1 I C1 C2 Cholestanyl unstabilized Vitamin E ferulate α-tocopherol (ppm) — 1075  — Cholestanyl ferulate (ppm) — — 1000  Calcium stearate (ppm) — 775 775

(4) The compositions comprising high density polyethylene (HDPE) (reactor powder SABIC® HDPE M80064) and the compositions according to Table 1 prepared in a Leistritz Micro 27/GL24 Schnecke 10.

(5) Processing Conditions:

(6) TABLE-US-00002 Screw speed 140 rpm Throughput 12 kg/h Residence time 15-35 s Specific energy 0.15 kW/kg

(7) Temperature profile (wherein rt=room temperature):

(8) TABLE-US-00003 Zone 1 rt Zone 2 rt Zone 3 210° C. Zone 4 215° C. Zone 5 220° C. Zone 6 220° C. Melt temperature 242° C.

(9) The ability to withstand thermo-oxidative stress in applications for a sufficient long time is determined using oven ageing. A forced air circulation oven for thermal (artificial) ageing provided by Binder GmbH (Model FP 115) with a calibrated air flow meter (set at 12-18 air changes per hour) was used.

(10) Compression moulded films produced with unstabilized HDPE M80064 (Comparative Example C1) HDPE M80064 and Vitamin E (Comparative Example C2) and HDPE M80064 and cholestanyl ferulate (Example I according to the invention) were oven aged at 115° C. Chemical changes due to degradation were monitored via FT-IR measurements.
Long Term Heat Ageing of Films
Compression Molding Films:

(11) For each sample two films (10×10 cm) were compression molded with thickness 80 μm. Thickness tolerance level of 20%.

(12) The press was heated to 160° C.

(13) Once this temperature was reached, the press cycle was the following:

(14) 1 minute with a pressure of 15 kN

(15) 3 minutes with a pressure of 100 kN

(16) Cooling down with a rate of 35° C./min until room temperature.

(17) Each film was labeled by scratching a name/code in the film.

(18) Set-Up Ovens

(19) In order to prevent direct contact between the films and the metal plates of the oven (avoid oxidation), following set-up was designed: steel bars were wrapped in Teflon tape preventing the films from touching the steel. The bars were put on the plates with metal wire. The films were attached to the bars and held by special magnets which can maintain their magnetism during high temperatures. These magnets were also wrapped in Teflon tape. Films were allowed to slightly overlap each other. For each sample two films were put in the oven, ageing was monitored by FT-IR.

(20) FT-IR

(21) Transmission FT-IR spectra of the films were measured on a Perkin Elmer Spectrum One with a DTGS detector. The spectral resolution was 4 cm−1. Transmission was measured between 4000-400 cm−1. 10 scans were taken of each film.

(22) Degree of oxidation [C═O]/100 μm is determined as the absorbance at 1713 cm−1 corrected to 100 μm film thickness (absorbance 1713 cm−1/film thickness [μm]*100).

(23) Lifetime/time to embrittlement (chemically) is defined as the time at which an upswing in degree of oxidation is detected after subjecting the samples to oven aging at 115° C. under an air flow (see FIG. 1).

(24) FIG. 1 proves that the long term heat performance related to lifetime/time to embrittlement of a polymer composition comprising cholestanyl ferulate is significantly higher compared to the unstabilised polymer and also compared to the polymer composition based on approximately equal amounts of Vitamin E.