POLYOLEFIN COMPOSITION FOR NON-ORIENTED FILM WITH IMRPOVED OXYGEN BARRIER PROPERTY
The present invention is directed to a polyolefin composition suitable for producing a non-oriented film with improved oxygen barrier property, and to such a non-oriented film. The polyolefin composition comprises a propylene homo-or copolymer, a hydrocarbon resin and optionally a nucleating agent. The present invention is also directed to the use of a hydrocarbon resin in a non-oriented film comprising a propylene homo- or copolymer for improving oxygen barrier property of said non-oriented film. The present invention allows the application of a polypropylene based non-oriented film like a cast film (CPP) for packaging of sensitive food.
1 . A polyolefin composition comprising:
(A) a propylene homo- or copolymer with an MFR 2 of 0.5-80 g/10 min as measured in accordance with ISO 1133, and
(B) a hydrocarbon resin product comprising a hydrocarbon resin, wherein the hydrocarbon resin has:
a weight average molecular weight of 500-5,000 g/mol, or
a melt viscosity of 80-400 mPa·s at 200° C. as measured according to ASTM D-3236, or
a softening point of 200° C. or less as measured according to ASTM E-28,
or by any combination thereof.
2 . The polyolefin composition according to claim 1 , further comprising:
(C) a nucleating agent.
3 . The polyolefin composition according to claim 2 , wherein the nucleating agent (C) is a polymeric alpha-nucleating agent.
4 . The polyolefin composition according to claim 1 , wherein component (A) is a propylene copolymer and the comonomer in component (A) is ethylene and/or a C 4 -C 8 -α-olefin, and the comonomer content is less than 7.5 mol. % based on the propylene copolymer.
5 . The polyolefin composition according to claim 1 , wherein component (A) is a propylene homopolymer.
6 . The polyolefin composition according to claim 1 , wherein the propylene homo- or copolymer (A) has a melting temperature (T m ) of at least 150.0° C. as measured by differential scanning calorimetry (DSC).
7 . The polyolefin composition according to claim 1 , wherein the propylene homo- or copolymer (A) has:
a flexural modulus of at least 1,400 MPa as measured according to ISO 178, and/or
a Vicat softening temperature of at least 140° C. as measured according to ISO 306.
8 . The polyolefin composition according to claim 1 , wherein the amount of the hydrocarbon resin product (B) is 1-40 wt. % based on the entire polyolefin composition.
9 . The polyolefin composition according to claim 1 , with the proviso that the composition does not comprise a blend of a polypropylene polymer having an MFR 2 of 2.9 g/10 min, 15 wt. % of a dicyclopentadiene based hydrocarbon resin having a softening point of 140° C., and 180 ppm of a nucleating agent.
10 . The polyolefin composition according to claim 1 , with the proviso that the composition does not comprise a blend of a propylene homopolymer having a density of 0.91 g/cm 3 and a melt index of 2.0 g/10 min, 15 wt. % of a fully hydrogenated hydrocarbon resin having a softening point of 125° C., and 3,000 ppm of 1,3:2,4-dibenzylidene sorbitol.
11 . The polyolefin composition according to claim 1 , with the proviso that the composition does not comprise a blend comprising a propylene ethylene random copolymer having a melt index at 230° C. and 2.16 kg load of 7.2 g/10 min, 0.3 wt.-% or 1.0 wt. % of a hydrocarbon resin, and 0.05 wt. % of calcium stearate.
12 . The polyolefin composition according to claim 1 , with the proviso that the composition does not comprise a blend of 83.3 wt. % of a polypropylene, 14.7 wt. % of a hydrocarbon resin, 0.08 wt. % of a nucleating agent, and 1.92 wt. % of a low density polyethylene.
13 . An article comprising a polyolefin composition according to claim 1 .
14 . The article according to claim 13 , wherein the article is a non-oriented film.
15 . The article according to claim 14 , wherein the cast film is obtained from the polyolefin composition in a cast film production process, wherein the chill roll has a temperature of 20-90° C.