A copolymer contains, based on the total amount of structural units of the copolymer, 90-99 mol % of propylene structural units and 1-10 mol % of butene structural units. The xylene solubles content of the copolymer is less than or equal to 4 wt %, and preferably less than or equal to 3 wt %. The propylene-butene copolymer is substantially free of fraction having a molecular weight lower than 1000. The copolymer has a melt flow index of greater than or equal to 20 g/10 min as measured at 230° C. under a load of 2.16 kg. The propylene-butene copolymer has a high melt flow index and few xylene solubles, and does not contain a phthalate-type plasticizer, and can be used in fields such as food and medical and health services.

Moulded articles comprising a polypropylene homopolymer with rather high melt flow rate, high stiffness, improved optical properties and an advantageous balance between stiffness and optical properties.

The present disclosure relates to a solid catalyst for propylene polymerization and a process for manufacture of a propylene polymer or copolymer using the solid catalyst, and provides a solid catalyst including carriers produced via a reaction between dialkoxy magnesium and metal halide, titanium halide, an organic electron donor, etc. and a process of manufacture of a propylene-based block copolymer via copolymerization of propylene--olefin using the solid catalyst. Particularly, internal electron donors including an ester group and an alkoxy group are used as two kinds of organic electron donors used in the present disclosure, and, thus, a block copolymer having high activity and excellent stereoregularity and a high rubber content via copolymerization with -olefin can be produced using a solid catalyst system suggested in the present disclosure.

Molded articles comprising a polypropylene homopolymer with rather high melt flow rate, high stiffness, improved optical properties and an advantageous balance between stiffness and optical properties.

The present disclosure relates to a solid catalyst for propylene polymerization and a process for manufacture of a propylene polymer or copolymer using the solid catalyst, and provides a solid catalyst including carriers produced via a reaction between dialkoxy magnesium and metal halide, titanium halide, an organic electron donor, etc. and a process of manufacture of a propylene-based block copolymer via copolymerization of propylene--olefin using the solid catalyst. Particularly, internal electron donors including an ester group and an alkoxy group are used as two kinds of organic electron donors used in the present disclosure, and, thus, a block copolymer having high activity and excellent stereoregularity and a high rubber content via copolymerization with -olefin can be produced using a solid catalyst system suggested in the present disclosure.