Process for inhibiting crust formation in reactors during alpha-olefin prepolymerization modification of Ziegler catalyst

Claim 2

A process for inhibiting crust formation in reactors during (alpha-olefin) prepolymerization modification of particles of catalytic solids containing titanium and chlorine in the combined state, comprising combining a (polylalpha-olefin) with the particles of catalytic solids in an amount of from 1% to 1000% by weight of the catalytic solids by carrying out the prepolymerization in the presence of solely silicone oil in an amount which is from 50 ppm to 1% by weight, relative to the weight of catalytic solids.

Claim 3

Process according to claim 1, characterized in that the amount of silicone oil is between about 50 ppm and about 5,000 ppm, relative to the weight of catalytic solids.

Claim 4

Process to claim 1, characterized in that the silicone oil contains a compound corresponding to the formula: ##STR2## in which R and R' are identical or different and represent an alkyl radical containing from 1 to 5 carbon atoms or an aryl radical, and in which x is between 3 add 2,000.

Claim 5

Process according to claim 3, characterized in that each of R and R' represent a methyl radical and in that the silicone oil has a kinematic viscosity at 25° C. of between about 0.5 and about 2×10 6 cSt.

Claim 6

Process according to claim 1, characterized in that the alpha-olefin is chosen from ethylene and propylene.

Claim 7

A process for inhibiting crust formation in reactors during alpha-olefin prepolymerization modification of particles of catalytic solids containing titanium and chlorine in the combined state, comprising conducting the prepolymerization in a reaction consisting essentially of the medium in which the particles of catalytic solids were prepared and a silicone oil in an amount of from 50 ppm to 1% by weight relative to the weight of the catalytic solids, wherein poly(alpha-olefin) in an amount of from 1 to 1000% of the weight of the catalytic solids is combined with said particles of catalytic solids, said particles of catalytic solids containing residues of an organo aluminum compound of the formula AlR n X 3-n , wherein R is a hydrocarbon radical containing from 1 to 20 carbons atoms, X is a halogen, and n is a number such that 0<n≦3, said prepolymerization taking place in the absence of the organo aluminum compound in the reaction medium.

Claim 8

A process for inhibiting crust formation in reactors during alpha-olefin prepolymerization modification of particles of catalytic solids containing titanium and chlorine in the combined state, comprising conducting the prepolymerization in a reaction consisting essentially of the medium in which the particles of catalytic solids were prepared and a silicone oil in an amount of from 50 ppm to 1% by weight relative to the weight of the catalytic solids, wherein poly(alpha-olefin) in an amount of from 1 to 1000% of the weight of the catalytic solids is combined with said particles of catalytic solids, said particles of catalytic solids containing residues of an organo aluminum compound of the formula AlR n X 3-n , wherein R is a hydrocarbon radical containing from 1 to 20 carbons atoms, X is a halogen, and n is a number such that 0<n≦3, said prepolymerization taking place in the absence of the organo aluminum compound in the reaction medium.

Claim 9

In a process for inhibiting crust formation in a reactor during α-olefin prepolymerization modification of particles of catalytic solids containing titanium and chlorine in the conbined state, the improvement comprising combining a poly(alpha-olefin) with the particles of catalytic solids in an amount between about 1% and 1000% by weight of the catalytic solids by prepolymerizing in a reaction medium consisting essentially of the liquid medium wherein the particles of catalytic solids were prepared and a silicone oil; said silicone oil being present in an amount between about 50 ppm and 1% by weight relative to the weight of catalytic solids; said prepolymerization taking place in the absence of an organo aluminum compound in the reaction medium.

Claim 10

In a process for inhibiting crust formation in a reactor during α-olefin prepolymerization modification of particles of catalytic solids containing titanium and chlorine in the conbined state, the improvement comprising combining a poly(alpha-olefin) with the particles of catalytic solids in an amount between about 1% and 1000% by weight of the catalytic solids by prepolymerizing in a reaction medium consisting essentially of the liquid medium wherein the particles of catalytic solids were prepared and a silicone oil; said silicone oil being present in an amount between about 50 ppm and 1% by weight relative to the weight of catalytic solids; said prepolymerization taking place in the absence of an organo aluminum compound in the reaction medium.

Claim 11

The process of claim 7 wherein the silicone oil is present in an amount between about 50 ppm and 5,000 ppm relative to the weight of catalytic solid.

Claim 12

The process of claim 7 wherein the silicone oil contains a compound corresponding to the formula: ##STR3## wherein R and R' are separately in each instance C 1 -C 5 alkyl or aryl, and x is between 3 and 2,000.

Claim 13

The process of claim 9 wherein each of R and R' are methyl, and the silicone oil has a kinematic viscosity at 25° C. of between about 0.5 and 2.10 6 cSt.

Claim 14

The process of claim 7 wherein the α-olefin is selected from the group consisting of ethylene and propylene.