Process for foaming using carbon dioxide solution

Abstract

The invention relates to a foaming process using carbon dioxide solution, comprising: put a parison into the carbon dioxide solution for primary foaming, remove and put the parison into the carbon dioxide solution for secondary foaming to get the foam product. Compared with foaming process using high-pressure gas directly, the foaming process using polar liquid system can get a uniform foam structure with high foaming rate faster, and has good foaming effect for high crystalline polymers. To control the change of temperature and pressure after the introduction of carbon dioxide, the impact and penetration of carbon dioxide on the surface of the crosslinked material can be controlled first, and the solubility of carbon dioxide in the polar system can be improved by further increasing pressure and temperature, thereby promoting the formation of uniform foam structure with high foaming rate in the subsequent heat foaming process.