Preparation method of polypropylene foamed beads

Abstract

The invention provides a preparation method of polypropylene foamed beads. The preparation method comprises the steps of preparing polypropylene according to a following method, adding organic peroxides into obtained polypropylene serving as matrix resin, and foaming by virtue of a physical foaming agent, so as to obtain the polypropylene foamed beads, wherein the method of polypropylene comprises the step of carrying out propylene polymerization reaction including two or more stages in two or more reactors which are connected in series for operation, wherein external electron donors used in the two stages are respectively alkane compounds and diether compounds. According to the preparation method, high-melt-strength polypropylene with wide molecular weight distribution is taken as a raw material, the organic peroxides are taken as a surface modifier of EPP beads, and the closed-hole-structured polypropylene foamed beads having the advantages that the diameters of foamed holes are uniform, the foamed holes are compact and the hole distribution is uniform can be prepared; the polypropylene foamed beads can be applied to the fields such as automobile manufacturing, packaging, building insulation, sport equipment, living goods, aerospace and the like.

Description

technical field [0001] The invention relates to the field of macromolecules, in particular to a method for preparing polypropylene foam beads. Background technique [0002] Polypropylene resin is used in many fields because of its excellent mechanical properties, machinability, high heat resistance, high cost performance and recyclability. Due to the consideration of light weight and rigidity, the use of polypropylene to prepare non-crosslinked foam materials has become the focus of attention in the fields of packaging materials, building materials, and heat insulation materials. In order to obtain products with different shapes and special uses, expanded polypropylene beads (EPP) have become the focus of development. Products of various shapes can be prepared by high-temperature steam molding using EPP. [0003] In the field of automobile manufacturing, PP moldings have been used in various parts, such as sun visors, car interiors, bumper cores, trunk lids, car roofs and ...

AI Technical Summary

Problems solved by technology

However, the existing high-rigidity polypropylene resin has a relatively high melting point, so a high molding temperature is required in the molding process, and high-pressure steam needs to be used, so special high-pressure-resistant molding equipment is required to achieve the foamed PP beads. Sufficient melt adhesion between them, thus increasing energy consumption and manufacturing cost

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