| 摘要 |
<p>PURPOSE:To prevent the lowering of Freon adsorption efficiency of activated charcoal in the recovery of Freon with activated charcoal from the gas generated during the preparation of urethane foam, by removing tolylene diisocyanate contained in the gas in advance. CONSTITUTION:In the preparation of urethane foam using Freon as a foaming agent, the generated gas is passed through a filtering medium composed of a urethane foam or nonwoven fabric impregnated with liquid polyether polyol, e.g. trifunctional polyether added with glycerin-base propylene oxide, or a polyester polyol, e.g. a condensed polyester derived from adipic acid and ethylene glycol to absorb and remove the tolylene diisocyanate contained in the generated gas. After the treatment, Freon is separated from the gas by adsorption with activated charcoal, and recovered as liquid Freon by desorption from activated charcoal with superheated steam followed by cooling.</p> |
