Polypropylene, preparation method and applications thereof

Abstract

The invention relates to the field of olefin polymerization, and particularly provides polypropylene, a preparation method and applications thereof, wherein the polypropylene has a melt flow index MFRof more than 30 g / 10 min, has an isotactic index of 96-99.5 wt%, and has a molecular weight distribution index MW / Mn of 3-5.5. The preparation method comprises: polymerizing propylene in the presenceof a catalyst under an olefin polymerization condition to obtain a polypropylene product, wherein the catalyst contains a catalyst component, an alkyl aluminum compound, and optionally an external electron donor, the catalyst component contains the product obtained by carrying out a reaction on a magnesium source, a titanium source and an internal electron donor, the internal electron donor contains a phosphate compound and a diether compound, and the phosphorus content (calculated as the phosphorus element) in the catalyst component is not more than 0.06 wt%. According to the present invention, the polypropylene integrates characteristics of high isotactic index, high melt flow index and narrow molecular weight distribution.

Description

technical field [0001] The invention relates to the field of olefin polymerization, in particular to a polypropylene, a method for preparing the polypropylene, the polypropylene prepared by the method and the application of the polypropylene in the preparation of fibers and non-woven fabrics. Background technique [0002] Polypropylene has many advantages, such as low density, high flexural modulus and melting point, good processability, excellent chemical stability, electrical insulation, and cheap and easy access to propylene raw materials required for the manufacture of polypropylene. However, although polypropylene material has these advantages, in some fields, due to its own characteristics, when it has a high melt flow index, the isotactic index is low; The bulk flow index is low, that is, polypropylene with a high melt flow index and a high isotactic index cannot be obtained. In the prior art, when the isotactic index of the propylene polymer is 96-99.5 wt%, the melt...

AI Technical Summary

Problems solved by technology

However, this processing method will bring some disadvantages, such as: increased processing steps, resulting in increased manufacturing costs; organic peroxides are unstable and difficult to handle; degradation reactions will produce toxic by-products, such as tert-butanol

Therefore, its application in some fields is limited, such as the field of food packaging

[0004] In addition, the performance of polypropylene can be improved by using high-performance polypropylene catalysts. At present, phthalate compounds (plasticizers) are relatively commonly used electron donors in polypropylene catalysts, but research has found that When the catalysts of phthalates are used to prepare products with a high melt index, due to their insufficient orientation ability, the isotactic index of the polymer is low, which cannot meet the product requirements, and it will cause serious damage to the growth and development of animals and the reproductive system. damage, meanwhile, may have similar effects on humans

Images