Solid CO2 supercritical foaming process

Abstract

The present invention relates to thermoplastic polymer foaming technology, and is especially solid CO2 supercritical foaming process. The solid CO2 supercritical foaming process includes mixing sodium bicarbonate and citric aid powder in certain proportion into plastic grains, heating the plastic grains to smelt into liquid with sodium bicarbonate and citric aid powder, increasing the temperature and pressure for sodium bicarbonate and citric aid to react chemically releasing CO2 in supercritical state and dissolved in liquid plastic, and lowering the temperature and pressure to foam and form the plastic. The process is simple, and has easy control on CO2 amount, high CO2 diffusion rate and dissolving rate, high production efficiency, low cost and high safety.

Description

Technical field: [0001] The invention relates to the technical field of thermoplastic polymer foaming technology, in particular to a solid carbon dioxide supercritical foaming technology. Background technique: [0002] After thermoplastic polymers (thermoplastics) are processed by foaming, bubble holes are formed inside the plastic, thereby reducing the weight of the plastic, reducing the amount of plastic used per unit volume, and reducing production costs. The above two points are the advantages of the thermoplastic polymer foaming process . The size of the cells produced by the traditional foaming process is large, the cell density is low, and the product is subject to many restrictions in terms of performance. At present, the microcellular foaming process and theory of thermoplastic polymers are very mature. The microcellular foaming process is Utilizing the characteristics of the gas in the supercritical state, the gas can quickly and evenly diffuse into the plastic in...

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Problems solved by technology

[0011] In the above-mentioned microcellular foaming process, carbon dioxide gas is injected through high-pressure equipment, and high-pressure gas infusion equipment must be equipped in the factory. The cost of high-pressure gas infusion equipment is high. Certain potential safety hazards require monitoring and maintenance at any time, high factory operating costs; the flow of carbon dioxide gas is difficult to control, and product quality is difficult to control; in addition, in the production process, carbon dioxide gas is directly poured into liquid thermoplastic polymers, although in Carbon dioxide gas has a high diffusion performance in a supercritical state, but during the mixing process of gaseous carbon dioxide and liquid thermoplastic polymers, its specific surface area is small, it is difficult to mix, and the mixing rate is low. Therefore, gaseous carbon dioxide and liquid thermoplastic polymers It is still relatively difficult to mix materials, and the mixing effect is poor, and the production efficiency is low

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