Method for preparing highly-conductive and highly-flame-retardant polypropylene foam beads

Abstract

The invention discloses a method for preparing highly-conductive and highly-flame-retardant polypropylene foam beads. The method comprises the following steps: 1) processing polypropylene A and a conductive filler to obtain a conductive master batch; 2) processing polypropylene A and a modified inorganic flame retardant to obtain a flame-retardant master batch 1; 3), processing polypropylene A andan organic flame retardant to obtain a flame-retardant master batch 2; 4), mixing polypropylene A, a nucleating agent master batch, the conductive master batch, the flame-retardant master batch 1 andthe flame-retardant master batch 2 to obtain conductive and flame-retardant polypropylene particles; and 5) filling a reactor with the conductive and flame-retardant polypropylene particles, a foaming agent and a dispersant, and performing high-temperature pressure relief process to obtain the foam beads. The obtained polypropylene foam beads undergo steam molding to form a plate, the density ofthe plate is 47-50 g / L, the surface resistance of the plate is stable at 800-1500 ohms, the oxygen index is 28% or above, and the obtained plate has a good microwave reflectivity in a frequency rangeof 0.2-1.0 GHz, and fills up the gap in highly-conductive and flame-retardant specific functional products in the foamed polypropylene bead type.

Description

technical field [0001] The invention relates to the technical field of preparation of polypropylene foam beads, in particular to a preparation method of highly conductive and highly flame-retardant polypropylene foam beads. Background technique [0002] Polypropylene expanded bead (EPP) products have excellent mechanical properties, high dimensional accuracy, and are easy to degrade and recycle, and are gradually replacing traditional polyethylene (PE), polystyrene (PS) and polyurethane (PU) foaming Materials are used in more and more fields. In addition to electronic packaging, transportation and auto parts industries, some functionalized EPP materials are gradually applied to their special fields, such as semi-conductive EPP materials used to absorb microwaves. [0003] Most of the foaming materials used in the field of microwave absorption are PU foams with conductive fillers adsorbed inside. Since PU foams have an open-pore structure, the adsorbed conductive fillers will...

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Problems solved by technology

[0005] The technical problem to be solved in the present invention is to overcome the technical problem that EPP materials cannot satisfy high conductivity and high flame retardancy at the same time, and obtain a microwave-absorbing EPP material through a new type of compound flame-retardant system and a preferred conductive filler. Production method of highly conductive and highly flame-retardant EPP beads

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