Thermoplastic polymer foam bead and method for preparing same

Abstract

The invention discloses a thermoplastic polymer foam bead and a method for preparing the same. The method includes 1), extruding and granulating foam-grade thermoplastic polymer resin compositions toobtain to-be-foamed particles; 2), placing the to-be-foamed particles constant-temperature high-pressure reaction kettles A, filling the constant-temperature high-pressure reaction kettles A with supercritical fluid and carrying out permeating and swelling to reach diffusion balance so as to form polymer-supercritical fluid homogenous systems; 3), transferring balanced to-be-foamed particles intohigh-pressure reaction kettles B by the aid of magnetic sealed stirring devices under the constant pressures; 4), unloading materials in the high-pressure reaction kettles B by the aid of quick opening ball valves under the pressures and foaming and expanding polymer particles to obtain the thermoplastic polymer foam bead. The pore diameters of the thermoplastic polymer foam bead range from 30 micrometers to 50 micrometers, and the rate of the thermoplastic polymer foam bead ranges from 10 times to 60 times.

Description

technical field [0001] The invention belongs to the field of new materials, in particular to a thermoplastic polymer foamed bead and a preparation method thereof. Background technique [0002] Polymer foamed beads have the characteristics of light weight, cushioning, high toughness, and easy molding, and are widely used in packaging, sporting goods, automobiles and other fields. The traditional bead foaming technology is often prepared by the high-pressure reactor method. The foaming process often uses organic solvents, chlorofluorocarbons and other foaming agents, which seriously pollute the environment and products. [0003] Supercritical fluid (SCF, supercritical fluid) refers to a fluid above the critical temperature and above the critical pressure. Because its viscosity and diffusion coefficient are close to those of gas, and its density and solvation ability are close to that of liquid, the advantages of fast diffusion rate and high solubility of supercritical fluid i...

AI Technical Summary

Problems solved by technology

[0004] In the high-pressure reactor process, due to the poor heat transfer of granular polymer particles in the high-pressure reactor, it will cause uneven heating inside and outside, and it is difficult to stir the material evenly in the common stirring form; The superheated particles on the inner wall are turned to the center, but this stirring often forms a projection on the bottom, which affects the smooth discharge of solid materials

Therefore, in the high-pressure reactor foaming process, the effect of uniform temperature is usually achieved by adding a heat-conducting medium (mainly water) and prolonging the reaction time, but this will lead to a long heating time of the material, high energy consumption, and increased post-processing Separate drying process, low production efficiency

At the same time, when the material is heated for a long time, it is often easy to agglomerate and agglomerate, which increases the difficulty of subsequent separation, the product qualification rate is low, and even the foaming cannot be completed smoothly.

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