Prepn of high flowability polypropylene

Abstract

The present invention relates to the preparation process of high flowability polypropylene and solves the technological problem of providing high energy ray preparation process of high melt flowability polypropylene. The present invention features that polypropylene grains are set inside high energy ray irradiation chamber and irradiated in the irradiation dosage over 100 Mrad at normal temperature for over 10 hr to obtain high flowability polypropylene with melt rate of flow MRF as high as 50-100 g/10 min. The present invention adopts high energy gamma ray with powerful penetration capacity and homogeneous degradation from inside grain to outside and can regulate the flowability of the polypropylene product easily via regulating irradiation dosage. The process of the present invention needs no mechanical stirring, low power consumption and low cost.

Description

technical field [0001] The present invention relates to a method for preparing high fluidity polypropylene. Background technique [0002] High-fluidity polypropylene is a new type of polymer material developed at home and abroad in recent years. It is suitable for thin-wall injection molding and has the characteristics of high impact strength and good surface properties. This type of resin has a wide adjustment range of molding shrinkage, and can be directly injection molded on the mold used by ABS or HIPS, and the surface of the product is treated with digestion, pearlescent or direct spraying. Products are mainly used in fibers, coatings, washing machine parts, auto parts, home appliance casings, etc. At present, the preparation methods of high fluidity polypropylene mainly include polymerization adjustment method and granulation degradation method. [0003] Polymerization Regulation. In the liquid-phase bulk gas-phase method polypropylene production equipment, the meth...

AI Technical Summary

Problems solved by technology

In the liquid-phase bulk gas-phase method polypropylene production equipment, the method of increasing the hydrogen concentration of the polymerization reaction is generally used to reduce the molecular weight of the polymer, thereby increasing the melt flow rate (MFR) of the copolymer. The advantage of this method is that the selection process is not demanding. The production is stable, but the disadvantage is that there are too many transition materials, and it is difficult to control the polymerization reaction.

The disadvantage is that it is difficult to ensure the uniformity of the addition of the degradation agent, resulting in different degrees of resin degradation, large index deviation, and affected fluidity; the low viscosity of the resin melt makes granulation difficult and difficult to control