Highly crystalline polypropylene with low xylene solubles
View Patent ↗The invention is directed to a polypropylene resin which has a M w /M n of less than 5, a melt flow rate of less than 7 g/10 min., a 1% secant flexural modulus of greater 5 than 300,000 psi and less than 2 wt. % xylene solubles.
1. A polypropylene homopolymer composition having a M w /M n of less than 5, a melt flow rate of less than 5 g/10 min, a 1% secant flexural modulus of greater than 300,000 psi, a pentad isotacticity of at least 98%, a haze of less than 25%, less than 2% by weight xylene solubles, and a crystallinity of at least 75%, wherein the polypropylene resin contains 500 ppm to less than 2500 ppm of a nucleator/clarifier additive.
2. The polypropylene resin of claim 1 , wherein the polypropylene resin has an isotactic pentad/triad ratio of greater than 95%.
3. The polypropylene resin of claim 2 wherein the polypropylene has a crystallization temperature of greater than 133° C.
4. A polyolefin composition, comprising:
(a) A polypropylene homopolymer composition having a M w /M n of less than 5, a melt flow rate of less than 5 g/10 min, a 1% secant flexural modulus of greater than 300,000 psi, a pentad isotacticity of at least 98%, less than 2% by weight xylene solubles, and a crystallinity of at least 75%;
(b) less than 40% by weight of an impact modifier having a density of from 0.885 g/ml to 0.91 g/ml,
wherein the polypropylene contains from 500 ppm to less than 2500 ppm of a nucleator/clarifier additive and exhibits a value of haze of less than 25%.
5. The polyolefin composition of claim 4 , wherein the polypropylene contains from 650 ppm to 1500 ppm of a nucleator/clarifier additive.
6. The polyolefin composition of claim 4 , wherein the density of the impact modifier is within 0.01 g/ml of a density of the polypropylene resin.
7. The polyolefin composition of claim 5 , wherein the density of the impact modifier is within 0.01 g/ml of a density of the polypropylene resin.