| 摘要 |
PURPOSE:To enhance the photoresist peeling effect and to remove simply and thoroughly chromium from waste water after peeling by adding a water soluble dihydric alcohol or a deriv. thereof to an alkaline aqueous soln. CONSTITUTION:To an alkaline aqueous soln. is added a water soluble dihydric alcohol or a deriv. thereof. The usable dihydric alcohol is propylene glycol, butylene glycol, pentanediol or the like, and the usable deriv. is propylene glycol monoethyl ether, dipropylene glycol or the like. The alkali agent is sodium hydroxide, potassium hydroxide or the like. Among those compounds propylene glycol and sodium hydroxide are desirably combined because they are easily available and economical. The preferred concn. of propylene glycol is 1- 20wt%. |
