The present invention provides a heterophasic polypropylene composition with good response to nucleating agents, increased crystallisation temperature, good mechanical properties The present invention further relates to articles made thereof, and the use of the heterophasic polypropylene composition for specific applications and producing these.

Embodiments are directed towards a use of a supported gas-phase biphenylphenol polymerization catalyst to make a polymer via a gas-phase polymerization process, wherein the supported gas-phase biphenylphenol polymerization catalyst is made from a gas-phase biphenylphenol polymerization precatalyst of Formula I.

Provided are a pellet-type polyethylene resin composition capable of improving pipe pressure resistance property, dimensional stability, and processability at the same time, and a method of preparing the same.

A process for preliminary polymerization may include washing a catalyst mud comprising a supported metallocene catalyst with at least one saturated hydrocarbon at a temperature from 0° C. to 40° C., a pressure from 20 to 40 kgf/cm.sup.2, and a residence time of at least 30 minutes; continuously feeding the washed catalytic mud to a continuous pre-polymerization reactor; and pre-polymerizing, in the continuous pre-polymerization reactor, ethylene and at least one C.sub.4 to C.sub.10 α-olefin as comonomer, with the washed catalytic mud, to produce a pre-polymer; wherein an average residence time in the continuous pre-polymerization reactor is more than 90 minutes and less than 240 minutes, a reactor temperature is from 10° C. to 50° C., and a reactor pressure from 20 to 40 kgf/cm.sup.2.

The metallocene compound represented by the following general formula (1): ##STR00001##
(the numerals and signs in the general formula (1) are as described in the description).

A spray-dried zirconocene catalyst system comprising a zirconocene catalyst and a hydrophobic fumed silica, which supports the zirconocene catalyst. A spray-drying method of making same. Polyolefins; methods of making and using same; and articles containing same.

The invention is directed to a beta nucleated heterophasic propylene copolymer composition (HPPC).

There is provided a method for preparing a metallocene-supported catalyst that exhibits catalytic activity, and yet, can decrease fine generation, and thus, can minimize fouling and chunk generation, and can stably prepare polyethylene having excellent properties.

There is provided a method for preparing a metallocene-supported catalyst that exhibits catalytic activity, and yet, can decrease fine generation, and thus, can minimize fouling and chunk generation, and can stably prepare polyethylene having excellent properties.

Catalyst systems and methods for making and using the same are disclosed. A catalyst composition is provided that includes a catalyst compound supported to form a supported catalyst system, the catalyst compound including: ##STR00001##
where each of R.sup.1, R.sup.2, R.sup.3, R.sup.4, R.sup.5, R.sup.6, R.sup.7 and X are as discussed herein.