Polypropylene composition for air quenched blown films
AssigneeBraskem America, Inc.
InventorsPeter E. Pierini, Shaun E. Pirtle
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Abstract
The invention is directed to a polypropylene resin, which is suitable for manufacturing an air quenched blown film. The resin has a melt flow rate of greater than 5 g/10 min, less than 2% xylene solubles, a pentad isotacticity of greater than 95%, an isotactic pentad/triad ratio of greater than 95%, a crystallinity of at least 65%, and a crystallization temperature of at least 127° C. The polypropylene resin contains from 500 ppm to 2500 ppm of a nucleator/clarifier additive. An quenched blown film made from resin exhibits a crystallization onset temperature of at least 116° C. and a crystallization half-life time of less 4.1 seconds or less when tested using fast DSC analysis with a scan rate of 200° C./minute.
Claims16
A polypropylene, suitable for forming a blown film, the polypropylene comprising:
- a homopolymer polypropylene having a Mw/Mn of less than 6.0, a melt flow rate in the range of from 8 to 13 g/10 min, less than 2% xylene solubles, a pentad isotacticity of greater than 95%, an isotactic pentad/triad ratio of greater than 95%, a crystallinity of at least 65%, and a crystallization temperature of at least 127° C., the polypropylene containing from 500 ppm to 2500 ppm of a nucleator/clarifier additive and wherein a blown film is capable of being manufactured from the resin at a rate of at least 6 lb/hr-in of die circumference and wherein a one mil thick blown film manufactured from the polypropylene using at least a 1.5 blow-up ratio exhibits a 1% secant modulus of at least 200,000 psi according to ASTM D882, a haze of less than 10 as measured by ASTM D1003, and a clarity of greater than 96%.
A polypropylene, suitable for forming a blown film, the polypropylene comprising:
- a polypropylene copolymer containing less than 2% by weight units of derived from ethylene and having a Mw/Mn of less than 6.0, a melt flow rate in the range of from 8 to 13 g/10 min, less than 3% xylene solubles, a pentad isotacticity of greater than 91%, an isotactic pentad/triad ratio of greater than 95%, a crystallinity of at least 65%, and a crystallization temperature of at least 127° C., the polypropylene containing from 750 ppm to 2500 ppm of a nucleator/clarifier additive, wherein said additive is aluminum hydroxybis[2,4,8,10-tetrakis(1,1-dimethylethyl)-6-hydroxy-12H-dibenzo[d,g][1,3,2]dioxaphosphocin-6-oxidato], and wherein a blown film is capable of being manufactured from the polypropylene at a rate of at least 6 lb/hr-in of die circumference and wherein a one mil thick blown film manufactured from the polypropylene using at least a 1.5 blow-up ratio exhibits a 1% secant modulus of at least 150,000 psi according to ASTM D882, a haze of less than 10 as measured by ASTM D1003, and a clarity of greater than 96%.
Dependencies are inferred from the claim text.