Ethylene-hexene-1 copolymer and process to produce ethylene-monoolefin copolymers

Claim 2

An ethylene-hexene-1 copolymer having a relative comonomer dispersity of 99% or higher.

Claim 3

The copolymer of claim 1 characterized by a relative comonomer dispersity of 100% or higher.

Claim 4

The copolymer of claim 1 or 2 characterized by a content of 1 to 6 mole percent 1-hexene and 99 to 94 mole percent ethylene, said copolymer having a maximum relative comonomer dispersity which is the sum of 100% plus the concentration of 1-hexene in mole percent.

Claim 5

A process to produce ethylene-monoolefin copolymers characterized by contacting a gas mixture containing ethylene and another monoolefin with a silica/titania/chromium oxide catalyst, said silica and titania being coprecipitated, under gas phase polymerization conditions in a polymerization zone such as to produce an ethylene-monoolefin-copolymer, and recovering said ethylene-monoolefin-copolymer.

Claim 6

A process to produce ethylene-monoolefin copolymers characterized by contacting a gas mixture containing ethylene and another monoolefin with a silica/titania/chromium oxide catalyst, said silica and titania being coprecipitated, under gas phase polymerization conditions in a polymerization zone such as to produce an ethylene-monoolefin-copolymer, and recovering said ethylene-monoolefin-copolymer.

Claim 7

The process of claim 4 characterized in that said catalyst is selected from one or more of (a) silica-titania-chromium tergels and (b) chromium supported on silica-titania cogels.

Claim 8

The process of claim 4 or 5 characterized by contacting ethylene and 1-butene with said catalyst, wherein said 1-butene is used in a concentration in mole percent in the gas phase based on total olefins in the gas phase in the polymerization zone as 100 mole percent which is defined by the following formula wherein CGB is the concentration of 1-butene in mole percent in the gas phase, CPB is the concentration of.1-butene in the copolymer and K4 is a factor in the range of 0.6 to 1.2; or comprising contacting ethylene and 1-hexene with said catalyst, wherein said 1-hexene is used in a concentration in mole percent in the gas phase based on total olefins in the gas phase in the polymerization zone, as 100 mole percent which is defined by the following formula wherein CGH is the concentration of 1-hexene in mole percent in the gas phase, CPH is the concentration of 1-hexene in the copolymer and K6 is a factor in the range of 1.4 to 2.5.

Claim 9

,7. The process of claim 4 or 5 characterized by contacting ethylene and 1-octene with said catalyst, wherein 1-octene is used in a concentration in mole percent in the gas phase based on total olefins in the gas phase in the polymerization zone as 100 mole percent which is defined by the following formula wherein CGO is the concentration of 1-octene in mole percent in the gas phase, CPO is the concentration of 1-octene in the copolymer and K8 is a factor in the range of 4 to 7; or comprising contacting ethylene and 4-methyl-1-pentene with said catalyst, wherein said 4-methyl-1-pentene is used in a concentration in mole percent in the gas phase based on total olefins in the gas phase in the polymerization zone as 100 mole percent which is defined by the following formula wherein CGF is the concentration of 4-methyl-1-pentene in mole percent in the gas phase, CPF is the concentration of 4-methyl-1-pentene in the copolymer and K51 is a factor in the range of 1 to 1.4.

Claim 10

The process of any of claims 4 to 7 characterized in that said polymerization step is carried out a pressure of 345 to 690 kPa gauge and at a temperature below 120°C; in particular wherein the polymerization temperature is in the range of 70 to 95°C.

Claim 11

The process of claim 6 or 7 for producing a copolymer having a density in the range of 0.915 to 0.935 g/ml and wherein the higher value of the range of K4 or respectively K6 or respectively K8 or respectively K51 is associated with the lower density of 0.915 g/ml and wherein the lower value of these values K4, K6, K8 and K51 relates to the higher density of the copolymer to be made.

Claim 12

The process of any of claims 4 to 8 characterized in that the polymerization is carried out with free hydrogen present in the gas phase of the polymerization zone.