Process for polymerizing monomers in fluidized beds

Claim 2

A continuous gas phase polymerization process comprising copolymerizing an alpha-olefin monomer with at least one other alpha-olefin comonomer in the presence of a silica-supported metallocene catalyst in a gas phase fluidized bed reactor operating in a condensed mode, said process further comprises a recycle stream passing through a fluidized bed in said reactor wherein the recycle stream comprises a dew point increasing component in an amount greater than 2.0 mole percent.

Claim 3

The process in accordance with claim 1 wherein said recycle stream composition is maintained at a ratio of C x /C y of less than 0.2, where C x and C y are the mole percent respectively of comonomer and monomer.

Claim 4

The process in accordance with claim 2 wherein the recycle stream further comprises hydrogen (H 2 ) in a mole ratio of H 2 /C y of less than 0.01.

Claim 5

The process in accordance with claim 1 wherein the silica-supported metallocene catalyst system comprises an alumoxane or an ionic activator.

Claim 6

The process in accordance with claim 1 wherein the weight percent of liquid based on the total weight of the recycle stream is greater than 5 weight percent to about 50 weight percent.

Claim 7

A continuous process for the polymerization of alpha-olefin monomer and at least one copolymerizable alpha-olefin comonomer in a gas phase fluidized bed reactor, said process comprising the steps of: a) passing a recycle stream through said reactor, said recycle stream comprising monomer, comonomer and hydrogen in a ratio of (C x +H 2 )/C y of less than 0.2, where C x , H 2 and C y are the mole percent respectively of comonomer, hydrogen and monomer, said recycle stream further comprising a dew point increasing component in an amount greater than 2.0 mole percent and optionally, a non-condensable inerts making up the balance of said recycle stream; b) introducing a polymerization catalyst into said reactor, the polymerization catalyst comprising a metallocene catalyst system supported on a particulate material comprising silica; c) withdrawing said recycle stream from the reactor; d) cooling said recycle stream to form a liquid and a gas phase; e) introducing into said recycle stream additional monomers to replace monomers polymerized to maintain said ratio of said recycle stream; f) reintroducing said liquid and gas phase into said reactor; and g) withdrawing said polymer product from said reactor.

Claim 8

A continuous process for the polymerization of alpha-olefin monomer and at least one copolymerizable alpha-olefin comonomer in a gas phase fluidized bed reactor, said process comprising the steps of: a) passing a recycle stream through said reactor, said recycle stream comprising monomer, comonomer and hydrogen in a ratio of (C x +H 2 )/C y of less than 0.2, where C x , H 2 and C y are the mole percent respectively of comonomer, hydrogen and monomer, said recycle stream further comprising a dew point increasing component in an amount greater than 2.0 mole percent and optionally, a non-condensable inerts making up the balance of said recycle stream; b) introducing a polymerization catalyst into said reactor, the polymerization catalyst comprising a metallocene catalyst system supported on a particulate material comprising silica; c) withdrawing said recycle stream from the reactor; d) cooling said recycle stream to form a liquid and a gas phase; e) introducing into said recycle stream additional monomers to replace monomers polymerized to maintain said ratio of said recycle stream; f) reintroducing said liquid and gas phase into said reactor; and g) withdrawing said polymer product from said reactor.

Claim 9

The process in accordance with claim 6 wherein the monomer and comonomer are alpha-olefins having from 2 to 15 carbon atoms.

Claim 10

The process in accordance with claim 6 wherein the catalyst has a reactivity ratio of less than 2.

Claim 11

The process in accordance with claim 6 wherein the catalyst productivity is greater than 2000 grams of polymer per gram of said catalyst.

Claim 12

The process in accordance with claim 6 wherein the mole percent of alpha-olefin monomer is from about 25 to 75 mole percent.

Claim 13

The process in accordance with claim 6 wherein the monomer partial pressure is in the range of from about 70 psia (482.8 kPaa) to about 240 psia (1655.2 kPaa).

Claim 14

The process in accordance with claim 6 wherein the mole ratio of H 2 /C y is less than 0.01.

Claim 15

The process in accordance with claim 6 wherein said recycle stream contains about 5 to about 60 mole percent of said dew point increasing component.

Claim 16

The process in accordance with claim 6 wherein the total weight percent of liquid based on the total weight of the recycle stream is greater than 2.5 weight percent.

Claim 17

The process in accordance with claim 6 wherein the dew point increasing component has at least one carbon less than the comonomer.

Claim 18

The process in accordance with claim 6 wherein said ratio is less than about 0.1.

Claim 19

The process in accordance with claim 6 wherein the liquid and the gas phases are introduced separately into the reactor.

Claim 20

The process in accordance with claim 6 wherein the polymer product having a density less than 0.910 g/cm 3 .

Claim 21

The process in accordance with claim 6 wherein the polymer product having a melt index greater than 3 dg/min.

Claim 22

The process in accordance with claim 6 wherein the polymer product having a density greater than 0.910 g/cm 3 .

Claim 23

The process in accordance with claim 6 wherein the polymer product having a melt index greater than 100 dg/min.

Claim 24

In a gas fluidized bed polymerization process for polymerizing alpha-olefins comprising, passing a recycle stream comprising a monomer and at least one comonomer through a fluidized bed reactor, withdrawing a polymeric product and a recycle stream comprising unreacted monomers, introducing into said recycle stream additional monomers to replace monomers polymerized and withdrawn, compressing and cooling said recycle stream to form a gas and a liquid phase and reintroducing said gas phase and said liquid phase into said reactor, the improvement comprising: maintaining the recycle stream at a monomer concentration in the range of from about 10-20 to about 80-90 mole percent, employing a silica-supported catalyst system comprising a metallocene catalyst and as the cocatalyst alumoxane or an ionic activated complex and passing the recycle stream through a fluidized bed in said reactor wherein the recycle stream further comprises a dew point increasing component in an amount greater than 2.0 mole percent.

Claim 25

In a gas fluidized bed polymerization process for polymerizing alpha-olefins comprising, passing a recycle stream comprising a monomer and at least one comonomer through a fluidized bed reactor, withdrawing a polymeric product and a recycle stream comprising unreacted monomers, introducing into said recycle stream additional monomers to replace monomers polymerized and withdrawn, compressing and cooling said recycle stream to form a gas and a liquid phase and reintroducing said gas phase and said liquid phase into said reactor, the improvement comprising: maintaining the recycle stream at a monomer concentration in the range of from about 10-20 to about 80-90 mole percent, employing a silica-supported catalyst system comprising a metallocene catalyst and as the cocatalyst alumoxane or an ionic activated complex and passing the recycle stream through a fluidized bed in said reactor wherein the recycle stream further comprises a dew point increasing component in an amount greater than 2.0 mole percent.

Claim 26

The process in accordance with claim 22 wherein the recycle stream further comprises hydrogen in a concentration in amount from about 10 ppm to about 10,000 ppm.

Claim 27

The process in accordance with claim 22 wherein the recycle stream further comprises nitrogen in amount from about 5 to about 50 mole percent.

Claim 28

The process in accordance with claim 22 wherein the recycle stream further comprises a dew point increasing component in amount from about 5 to about 50 mole percent.

Claim 29

The process in accordance with claim 22 wherein the liquid phase in said recycle stream is greater than about 5 to 40 weight percent based on the total weight of the recycle stream.

Claim 30

The process in accordance with claim 22 wherein said polymer product has a CDBI greater than 50 percent.

Claim 31

The process in accordance with claim 22 wherein the polymer product produced has a density in the range of from 0.850 g/cm 3 to 0.970 g/cm 3 .

Claim 32

The process in accordance with claim 28 wherein said polymer product has a melt index of at least 0.01 dg/min and less than 1000 dg/min.

Claim 33

The process in accordance with claim 22 wherein said monomers are alpha-olefin monomers having from 2 to 20 carbon atoms.

Claim 34

The process in accordance with claim 30 wherein said monomers are C 4 and C 2 alpha-olefins in the ratio of from about 0.001 to about 0.2.

Claim 35

The process in accordance with claim 30 wherein said monomers are C 5 and C 2 alpha-olefins in the ratio of from about 0.001 to about 0.15.

Claim 36

The process in accordance with claim 30 wherein said monomers are C 6 and C 2 alpha-olefins in the ratio of from about 0.001 to 0.1.

Claim 37

The process in accordance with claim 30 wherein said monomers are C 8 and C 2 alpha-olefins in the ratio of from about 0.001 to 0.05.