Preparation method of reinforced polypropylene foamed beads

Abstract

The invention relates to a preparation method of reinforced polypropylene foamed beads. The method comprises the following steps of: (a), mixing, extruding, drawing and pelletizing two polypropylene resins and nucleation auxiliary agent through an extruder to prepare polypropylene particles; and (b), putting the reinforced polypropylene particles in a reaction kettle for heating and pressing to generate outward expanding internal pressure under high temperature and high pressure, and temporarily releasing the internal pressure to atmosphere to obtain the reinforced polypropylene foamed beads with certain multiplying power. In the step (a), two polypropylene resins comprise one easily-crystallized polypropylene raw material and one high-melting-point polypropylene raw material; the melting point of the high-melting-point polypropylene is 150-170 DEG C; nucleation agent is added in the step (a) and accounts for 0.01-2% of the adding amount of the two polypropylene resins by weight percentage; and the particle size of the nucleation agent is 0.5-2 microns.

Description

technical field [0001] The invention relates to a preparation method of reinforced polypropylene foam beads, which are applied to the fields of automotive interior parts, packaging materials, building materials, heat insulation materials and the like. Background technique [0002] Expanded polypropylene materials include various engineering plastics and are used in various fields due to their excellent mechanical strength, heat resistance, machinability, flame resistance, and recyclability. For example, automotive interior parts, packaging materials, building materials, heat insulation materials, etc. Especially in the field of transportation such as automobiles, expanded polypropylene materials have been used in various parts such as bumpers, sun visors, tool boxes, seats, etc. [0003] Currently, there is an increasing demand for expanded polypropylene products with higher strength and lighter weight than ordinary EPP. For example, in the automotive field, bumper inner c...

AI Technical Summary

Problems solved by technology

[0008] The previous increase in EPP was to strengthen a single particle from the perspective of cross-linking. On the one hand, it increased the cost in actual production, and at the same time, the addition of cross-linking agent made the process control more strict and cumbersome; From a perspective, cross-linked EPP limits its application for recycling

[0009] Due to the slow nucleation rate of polypropylene, the degree of crystallinity is reduced, and the formed spherulites are not fine enough, resulting in the failure of polypropylene to achieve the best performance in terms of rigidity.

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