Propylene ethylene random copolymer suitable for pipe
View Patent ↗A composition is provided which comprises a propylene ethylene random copolymer having a melt flow rate (MFR) (as determined according to ASTM D1238, 230° C., 2.16 Kg) of less than 1 g/10 min, a xylene solubles content of less than 7% by weight, an ethylene content of from 3 to 5 percent by weight of the copolymer, and a value equal to or greater than 92 for the product of the Koenig B value times the % mm triads measured on the xylene insoluble fraction of the random copolymer obtained by the wet method. Pipes made from the composition demonstrate improved pressure endurance.
1. A composition suitable for pipe applications comprising a propylene ethylene random copolymer, the copolymer having the following properties:
(A) a melt flow rate (MFR) less than 1 g/10 min as determined according to ASTM D1238, at 230° C. and 2.16 kg;
(B) an ethylene content of from 3 to 5 percent by weight of the random copolymer;
(C) a xylene insoluble fraction of the random copolymer which is obtained by the wet method, wherein said fraction exhibits a [(Koenig B value)*(% mm)]≥92; and
(D) a xylene solubles content measured by the wet method of ≤7.0% by weight.
2. The composition of claim 1 wherein the xylene insoluble fraction of the copolymer obtained by the wet method is further characterized by having a Koenig B value equal to or greater than 0.95.
3. The composition of claim 1 wherein the (percentage mm of the xylene insoluble fraction of the copolymer obtained by the wet method)×(Koenig B value of the xylene insoluble fraction of the copolymer obtained by the wet method) is greater than 92.0 to less than 100.
4. The composition of claim 1 wherein the copolymer has an ethylene content of from 3.2 to 4.2 percent by weight of the copolymer.
5. The composition of claim 1 wherein the copolymer is further characterized by having a Polymer Dispersity Index (PDI) greater than 4.0.
6. The composition of claim 1 wherein the copolymer is characterized as having a PDI≥4.0, xylene solubles content as measured by the wet method ≤7% by weight, Koenig B value of the xylene insoluble fraction of the copolymer obtained by the wet method ≥0.95 and a percentage mm of the xylene insoluble fraction of the copolymer obtained by the wet method ≥97.
7. The composition of claim 1 wherein the copolymer is beta nucleated.
8. The composition of claim 1 in the form of a pipe and wherein the pipe has a pressure endurance of at least 700 hours when tested at 90° C. and 5 MPa.
9. The composition of claim 1 which is further characterized as containing substantially no phthalate compositions.
10. The composition of claim 1 wherein MFR is from 0.1 to 0.5 g/10 min.