초록

The present invention provides a method and apparatus which permits recovering and reusing the volatile blowing agents which are used in the production of thermoplastic foams.

대표청구항 ▼

A process for recovering the volatile blowing agents employed in the production of expanded foam thermoplastic materials to permit their reuse in the production of the foam thermoplastic materials and to also reduce emissions of the blowing agents to the atmosphere, said process comprising extruding

A process for recovering the volatile blowing agents employed in the production of expanded foam thermoplastic materials to permit their reuse in the production of the foam thermoplastic materials and to also reduce emissions of the blowing agents to the atmosphere, said process comprising extruding a solution of the thermoplastic material and volatile blowing agent into a confined area while volatilizing the blowing agent to thereby expand and foam the thermoplastic material, withdrawing from the confined area a stream of air containing the volatile blowing agent at a relatively low concentration, concentrating the stream of withdrawn blowing agent-laden air by selective adsorption-desorption of the volatile blowing agent on an absorbent to increase the blowing agent concentration, liquefying the blowing agent present in said concentrated stream of blowing agent-laden air to produce a liquid blowing agent vapor and air, and separating the liquid blowing agent phase from the gaseous phase and recovering the liquid blowing agent for reuse in the production of the foam thermoplastic material.