This invention relates to a self cleaning reactor and to a process for the oligomerization of ethylene that employs a self-cleaning reactor. The reactor includes a mass of inert, particulate cleaning bodies that are entrained by the liquid in the reactor and scour the internal surfaces of the reactor during normal operation. This scouring action reduces the level of fouling on the reactor surfaces. Foulant material (polyethylene) is removed from the process on a continuous basis but the cleaning bodies remain within the reactor.

Embodiments of polyethylene formulations and articles comprising polyethylene formulations are disclosed. The polyethylene formulation may include from 45 wt. % to 90 wt. % of an MDPE having a density of from 0.930 g/cc to 0.950 g/cc and a melt index (I.sub.2) from 0.05 g/10 min to 0.5 g/10 min; from 10 wt. % to 50 wt. % of a polyethylene composition having a density from 0.910 g/cc to 0.936 g/cc and a melt index (I.sub.2) from 0.7 g/10 min to 1.0 g/10 min; and from 0.5 wt. % to 5% of a masterbatch composition. The polyethylene composition may comprise a first polyethylene fraction area in a temperature range of 45° C. to 87° C. of an elution profile via improved comonomer composition distribution (iCCD) analysis method and a second polyethylene fraction area in a temperature range of 95° C. to 120° C. of an elution profile via iCCD.

Embodiments of polyethylene formulations and articles comprising polyethylene formulations are disclosed. The polyethylene formulation may include from 45 wt. % to 90 wt. % of an MDPE having a density of from 0.930 g/cc to 0.950 g/cc and a melt index (I.sub.2) from 0.05 g/10 min to 0.5 g/10 min; from 10 wt. % to 50 wt. % of a polyethylene composition having a density from 0.910 g/cc to 0.936 g/cc and a melt index (I.sub.2) from 0.7 g/10 min to 1.0 g/10 min; and from 0.5 wt. % to 5% of a masterbatch composition. The polyethylene composition may comprise a first polyethylene fraction area in a temperature range of 45° C. to 87° C. of an elution profile via improved comonomer composition distribution (iCCD) analysis method and a second polyethylene fraction area in a temperature range of 95° C. to 120° C. of an elution profile via iCCD.

Embodiments of polyethylene formulations and articles comprising polyethylene formulations are disclosed. The polyethylene formulation may include from 45 wt. % to 90 wt. % of an MDPE having a density of from 0.930 g/cc to 0.950 g/cc and a melt index (I.sub.2) from 0.05 g/10 min to 0.5 g/10 min; from 10 wt. % to 50 wt. % of a polyethylene composition having a density from 0.910 g/cc to 0.936 g/cc and a melt index (I.sub.2) from 0.7 g/10 min to 1.0 g/10 min; and from 0.5 wt. % to 5% of a masterbatch composition. The polyethylene composition may comprise a first polyethylene fraction area in a temperature range of 45° C. to 87° C. of an elution profile via improved comonomer composition distribution (iCCD) analysis method and a second polyethylene fraction area in a temperature range of 95° C. to 120° C. of an elution profile via iCCD.

The present invention relates to a method for preparing a catalyst, and in particular provides a method for preparing a catalyst suitable for the polymerisation of ethylene and/or propylene, said catalyst comprising a compound of yttrium, neodymium or scandium supported on a silica support, and wherein the method comprises: a) Treating a silica support by heating at a temperature of at least 550° C., b) Contacting the treated silica support with a complex of the following formula: D.sub.mMX.sup.1X.sup.2R wherein M is selected from Y, Sc and Nd, R is a hydrocarbyl group, X.sup.1 and X.sup.2 are anionic groups, D is a neutral donor group, and m is 0 or greater.

The present invention relates to a method for preparing a catalyst, and in particular provides a method for preparing a catalyst suitable for the polymerisation of ethylene and/or propylene, said catalyst comprising a compound of yttrium, neodymium or scandium supported on a silica support, and wherein the method comprises: a) Treating a silica support by heating at a temperature of at least 550° C., b) Contacting the treated silica support with a complex of the following formula: D.sub.mMX.sup.1X.sup.2R wherein M is selected from Y, Sc and Nd, R is a hydrocarbyl group, X.sup.1 and X.sup.2 are anionic groups, D is a neutral donor group, and m is 0 or greater.

A polypropylene comprising within a range from 0.1 wt % to 4 wt % ethylene and/or C4 to C12 α-olefin derived units, one or more clarifiers, or both; wherein the polypropylene has a flexural modulus of at least 200 kpsi (0.05 in/min ASTM D790(A)) and an Mz/Mw of at least 4. The polypropylenes may be made by combining propylene and a comonomer with a Ziegler-Natta catalyst and at least two external electron donors, wherein the concentration of the electron donors is within a range from 1 to 100 ppm. The concentration of electron donors may be decreased to control the haze level of the polypropylene, and/or the level of comonomer derived units may be controlled to reduce the haze level of the polypropylene.

A polypropylene comprising within a range from 0.1 wt % to 4 wt % ethylene and/or C4 to C12 α-olefin derived units, one or more clarifiers, or both; wherein the polypropylene has a flexural modulus of at least 200 kpsi (0.05 in/min ASTM D790(A)) and an Mz/Mw of at least 4. The polypropylenes may be made by combining propylene and a comonomer with a Ziegler-Natta catalyst and at least two external electron donors, wherein the concentration of the electron donors is within a range from 1 to 100 ppm. The concentration of electron donors may be decreased to control the haze level of the polypropylene, and/or the level of comonomer derived units may be controlled to reduce the haze level of the polypropylene.

The invention relates to a metallocene complex according to formula (I), (I) wherein R.sub.1 and R.sub.2 are independently selected from H, an alkyl or an aryl group, wherein R.sub.3 is a C1-C10 alkyl group, wherein R′ is selected from H, an alkyl group, an aryl group and wherein different R′ substituents can be connected to form a ring structure and wherein B is a 1,2 phenylene bridging moiety, which can be optionally substituted, wherein Mt is selected from Ti, Zr and Hf, X is an anionic ligand, z is the number of X groups and equals the valence of Mt minus 2. The invention also relates to a catalyst comprising the reaction product of the metallocene complex and a cocatalyst. Further the invention relates to a (co)polymerisation process of olefinic monomers. ##STR00001##

The invention relates to a metallocene complex according to formula (I), (I) wherein R.sub.1 and R.sub.2 are independently selected from H, an alkyl or an aryl group, wherein R.sub.3 is a C1-C10 alkyl group, wherein R′ is selected from H, an alkyl group, an aryl group and wherein different R′ substituents can be connected to form a ring structure and wherein B is a 1,2 phenylene bridging moiety, which can be optionally substituted, wherein Mt is selected from Ti, Zr and Hf, X is an anionic ligand, z is the number of X groups and equals the valence of Mt minus 2. The invention also relates to a catalyst comprising the reaction product of the metallocene complex and a cocatalyst. Further the invention relates to a (co)polymerisation process of olefinic monomers. ##STR00001##