Ethylene polymerization with silane modified catalyst

Claim 2

In a process for polymerizing a monomer charge comprising ethylene by contacting said charge with activated inorganic oxide supported bis(cyclopentadienyl) chromium [II] catalyst wherein said inorganic oxide is selected from the group consisting of silica, alumina, thoria, zirconia and mixtures thereof, and the bis(cyclopentadienyl) chromium [II] compound has the structure ##STR7## wherein n' and n" are each integers of 0 to 5, inclusive, and R' and R" are each C 1 to C 20 , inclusive, hydrocarbon radicals, the improvement which comprises modifying said catalyst prior to said contact with said monomer charge by contacting said catalyst with, per mol of the organochromium compound, 0.01 to 20 mols of at least one modifying compound having in its structure at least one moiety of the formula ##STR8## said modifying compound being devoid of OH, SH, NH 2 , COOH, halogen, alkoxy and aryloxy radicals in such amounts as would poison the polymerization system under the prevailing reaction conditions, and said modifying with said modifying compound providing a modified catalyst with which, in comparison to the use of the unmodified catalyst in said polymerization process, polymers of improved impact strength are prepared.

Claim 3

A process as in claim 1 wherein said modifier comprises a mono- or di- alkoxy silane.

Claim 4

A process as in claim 2 wherein said alkoxy silane comprises trimethylethoxy silane.

Claim 5

A process as in claim 1 in which said monomer charge consists of ethylene.

Claim 6

A process as in claim 1 in which said monomer charge comprises ethylene and at least one α-olefin containing 3 to about 12 carbon atoms.

Claim 7

A process as in claim 5 in which said monomer charge comprises ethylene and propylene.

Claim 8

A process as in claim 1 in which about 0.05 to 12 mols of modifier are used per mole of the organochromium compound.

Claim 9

A process as in claim 1 in which said support is silica.

Claim 10

A process as in claim 4 in which said support is silica.

Claim 11

A process as in claim 5 in which said support is silica.

Claim 12

An olefin polymerization catalyst which comprises bis(cyclopentadienyl) chromium [II] compound of the structure ##STR9## wherein n' and n" are each integers of 0 to 5, inclusive, and R' and R" are each C 1 to C 20 , inclusive, hydrocarbon radicals, supported on activated inorganic oxide having a surface area of about 50 to 1000 square meters per gram and selected from the group consisting of silica, alumina, thoria, zirconia and mixtures thereof, and modified by being contacted with, per mol of the organochromium compound, 0.01 to 20 mols of at least one modifying compound having in its structure at least one moiety of the formula ##STR10## said modifying compound being devoid of OH, SH, NH 2 , COOH, halogen, alkoxy and aryloxy radicals in such amounts as would poison the polymerization system under the prevailing reaction conditions, and said modifying compound being adapted to so modify the unmodified catalyst by said modifying that the modified catalyst is adapted to provide, in comparison to the use of the unmodified catalyst for olefin polymerization purposes, polymers of improved impact strength.

Claim 13

An olefin polymerization catalyst which comprises bis(cyclopentadienyl) chromium [II] compound of the structure ##STR9## wherein n' and n" are each integers of 0 to 5, inclusive, and R' and R" are each C 1 to C 20 , inclusive, hydrocarbon radicals, supported on activated inorganic oxide having a surface area of about 50 to 1000 square meters per gram and selected from the group consisting of silica, alumina, thoria, zirconia and mixtures thereof, and modified by being contacted with, per mol of the organochromium compound, 0.01 to 20 mols of at least one modifying compound having in its structure at least one moiety of the formula ##STR10## said modifying compound being devoid of OH, SH, NH 2 , COOH, halogen, alkoxy and aryloxy radicals in such amounts as would poison the polymerization system under the prevailing reaction conditions, and said modifying compound being adapted to so modify the unmodified catalyst by said modifying that the modified catalyst is adapted to provide, in comparison to the use of the unmodified catalyst for olefin polymerization purposes, polymers of improved impact strength.

Claim 14

A catalyst as in claim 11 wherein the support comprises silica.

Claim 15

A catalyst as in claim 12 wherein about 0.05 to 12 mols of modifier are used per mol of the organochromium compound.

Claim 16

A catalyst as in claim 13 wherein the modifier comprises a mono- or di- alkoxy silane.

Claim 17

A catalyst as in claim 14 wherein the modifier comprises trimethylethoxy silane.

Claim 18

A process for improving the properties, as an ethylene polymerization catalyst, of activated inorganic oxide supported bis(cyclopentadienyl) chromium [II] compound, wherein the inorganic oxide has a surface area of about 50 to 1000 square meters per gram and is selected from the group consisting of silica, alumina, thoria, zirconia and mixtures thereof, and the bis(cyclopentadienyl) chromium [II] compound has the structure ##STR11## wherein n' and n" are each integers of 0 to 5, inclusive, and R' and R" are each C 1 to C 20 , inclusive, hydrocarbon radicals, which comprises modifying the supported bis(cyclopentadienyl) chromium [II] compound by contacting it with 0.01 to 20 mols of silane compound per mol of said bis(cyclopentadienyl) chromium [II] compound, said silane compound being devoid of OH, SH, NH 2 , COOH, halogen, alkoxy and aryloxy radicals in such amounts as would poison the polymerization reaction under the prevailing reaction conditions, and said silane compound being adapted to so modify the unmodified catalyst by said modifying that the modified catalyst is adapted to provide, in comparison to the use of the unmodified catalyst for olefin polymerization purposes, polymers of improved impact strength.

Claim 19

A process for improving the properties, as an ethylene polymerization catalyst, of activated inorganic oxide supported bis(cyclopentadienyl) chromium [II] compound, wherein the inorganic oxide has a surface area of about 50 to 1000 square meters per gram and is selected from the group consisting of silica, alumina, thoria, zirconia and mixtures thereof, and the bis(cyclopentadienyl) chromium [II] compound has the structure ##STR11## wherein n' and n" are each integers of 0 to 5, inclusive, and R' and R" are each C 1 to C 20 , inclusive, hydrocarbon radicals, which comprises modifying the supported bis(cyclopentadienyl) chromium [II] compound by contacting it with 0.01 to 20 mols of silane compound per mol of said bis(cyclopentadienyl) chromium [II] compound, said silane compound being devoid of OH, SH, NH 2 , COOH, halogen, alkoxy and aryloxy radicals in such amounts as would poison the polymerization reaction under the prevailing reaction conditions, and said silane compound being adapted to so modify the unmodified catalyst by said modifying that the modified catalyst is adapted to provide, in comparison to the use of the unmodified catalyst for olefin polymerization purposes, polymers of improved impact strength.

Claim 20

A process as in claim 16 in which said silane compound comprises mono- or di- alkoxy silane.

Claim 21

A process as in claim 17 in which said silane compound comprises trimethylethoxy silane.

Claim 22

A process as in claim 1 which is conducted under slurry conditions.

Claim 23

A process as in claim 1 which is conducted in a fluid bed reactor.