The present invention relates to use of optionally monosubstituted 2,2-di(tetrahydrofuryl)methanes, as internal donors in Ziegler-Natta catalysts to obtain polymers with desirable properties. The present disclosure further concerns Ziegler-Natta catalyst components comprising said optionally monosubstituted 2,2-di(tetrahydrofuryl)methanes and Ziegler-Natta catalysts for olefin polymerization comprising said Ziegler-Natta catalyst components as well as a method for preparing the same and their use in providing polyolefins.

The present invention relates to use of optionally monosubstituted 2,2-di(tetrahydrofuryl)methanes, as internal donors in Ziegler-Natta catalysts to obtain polymers with desirable properties. The present disclosure further concerns Ziegler-Natta catalyst components comprising said optionally monosubstituted 2,2-di(tetrahydrofuryl)methanes and Ziegler-Natta catalysts for olefin polymerization comprising said Ziegler-Natta catalyst components as well as a method for preparing the same and their use in providing polyolefins.

A process for propylene preliminary polymerization in liquid phase that occurs in a continuous preliminary polymerization reactor may include feeding a propylene monomer and a Ziegler-Natta catalyst system having (a) a pro-catalyst having an internal electron donor comprising a substituted phenylene aromatic diester, (b) a catalyst activator and optionally (c) an external donor, into the continuous preliminary polymerization reactor, wherein the feeding is carried out without pre-contact of the pro-catalyst with the catalyst activator, and also without pre-contact of the catalyst activator with the propylene monomer before entering the continuous preliminary polymerization reactor.

A process for propylene preliminary polymerization in liquid phase that occurs in a continuous preliminary polymerization reactor may include feeding a propylene monomer and a Ziegler-Natta catalyst system having (a) a pro-catalyst having an internal electron donor comprising a substituted phenylene aromatic diester, (b) a catalyst activator and optionally (c) an external donor, into the continuous preliminary polymerization reactor, wherein the feeding is carried out without pre-contact of the pro-catalyst with the catalyst activator, and also without pre-contact of the catalyst activator with the propylene monomer before entering the continuous preliminary polymerization reactor.

The purpose of the present invention is to provide a propylene-based block copolymer, the deposition thereof on the inner wall of the polymerization vessel having been sufficiently inhibited. The propylene-based block copolymer of the present invention has a flowability evaluation value of 40% or less, the value being calculated with the following equation wherein X (sec) is the number of seconds over which 100 g of the copolymer having ordinary temperature falls from a stainless-steel funnel having an inner diameter of 11.9 mm and Y (sec) is the number of seconds over which 100 g of the copolymer which has been held at 80° C. for 24 hours under a load of 10 kg falls from the funnel having an inner diameter of 11.9 mm.
Flowability evaluation value (%)={(Y/X)−1}×100.

The purpose of the present invention is to provide a propylene-based block copolymer, the deposition thereof on the inner wall of the polymerization vessel having been sufficiently inhibited. The propylene-based block copolymer of the present invention has a flowability evaluation value of 40% or less, the value being calculated with the following equation wherein X (sec) is the number of seconds over which 100 g of the copolymer having ordinary temperature falls from a stainless-steel funnel having an inner diameter of 11.9 mm and Y (sec) is the number of seconds over which 100 g of the copolymer which has been held at 80° C. for 24 hours under a load of 10 kg falls from the funnel having an inner diameter of 11.9 mm.
Flowability evaluation value (%)={(Y/X)−1}×100.

A process for preparing a catalyst component made from or containing Mg, Ti, and at least an electron donor compound (ID), including the steps of: (a) reacting a Mg based compound with a Ti compound, having at least a Ti—Cl bond, in an amount such that the Ti/Mg molar ratio is greater than 3 and at a temperature ranging from 0 to 150° C., thereby yielding an intermediate solid catalyst component containing Mg and Ti; and (b) contacting the intermediate solid catalyst component with a gaseous stream containing the electron donor compound (ID) in a gaseous dispersing medium, thereby yielding a final solid catalyst component having an ID/Ti molar ratio ranging from 0.5:1 to 20:1.

A process for preparing a catalyst component made from or containing Mg, Ti, and at least an electron donor compound (ID), including the steps of: (a) reacting a Mg based compound with a Ti compound, having at least a Ti—Cl bond, in an amount such that the Ti/Mg molar ratio is greater than 3 and at a temperature ranging from 0 to 150° C., thereby yielding an intermediate solid catalyst component containing Mg and Ti; and (b) contacting the intermediate solid catalyst component with a gaseous stream containing the electron donor compound (ID) in a gaseous dispersing medium, thereby yielding a final solid catalyst component having an ID/Ti molar ratio ranging from 0.5:1 to 20:1.

An ultra-high molecular weight, ultra-fine particle size polyethylene has a viscosity average molecular weight (Mv) greater than 1×10.sup.6. The polyethylene is spherical or are sphere-like particles having a mean particle size of 10-100 μm, having a standard deviation of 2-15 μm and a bulk density of 0.1-0.3 g/mL. Using the polyethylene as a basic polyethylene, a grafted polyethylene can be obtained by means of a solid-phase grafting method; and a glass fiber-reinforced polyethylene composition comprising the polyethylene and glass fibers, and a sheet or pipe prepared therefrom; a solubilized ultra-high molecular weight, ultra-fine particle size polyethylene; and a fiber and a film prepared from the solubilized ultra-high molecular weight, ultra-fine particle size polyethylene may also be obtained. The method has simple steps, is easy to control, has a relatively low cost and a high repeatability, and can realize industrialisation.

An ultra-high molecular weight, ultra-fine particle size polyethylene has a viscosity average molecular weight (Mv) greater than 1×10.sup.6. The polyethylene is spherical or are sphere-like particles having a mean particle size of 10-100 μm, having a standard deviation of 2-15 μm and a bulk density of 0.1-0.3 g/mL. Using the polyethylene as a basic polyethylene, a grafted polyethylene can be obtained by means of a solid-phase grafting method; and a glass fiber-reinforced polyethylene composition comprising the polyethylene and glass fibers, and a sheet or pipe prepared therefrom; a solubilized ultra-high molecular weight, ultra-fine particle size polyethylene; and a fiber and a film prepared from the solubilized ultra-high molecular weight, ultra-fine particle size polyethylene may also be obtained. The method has simple steps, is easy to control, has a relatively low cost and a high repeatability, and can realize industrialisation.