| 摘要 |
<p>PROBLEM TO BE SOLVED: To obtain a defoaming agent capable of effectively controlling and suppressing the amount foamed in a deinking step for waste paper without inhibiting the deinking effects of a deinking agent at all by including a specific polyalkylene glycol derivative. SOLUTION: This defoaming agent is represented by formula I [R1 is a hydrocarbon or an acyl; (AO)n is a polyoxyalkylene formed by copolymerization of ethylene oxide with a >=3C alkylene oxide; (n) is 3-15; with the proviso that the proportion of the oxyethylene occupied in the (AO)n is 5-20 mol% based on the total oxyalkylene]. Furthermore, a composition for a deinking treatment is preferably prepared by including a deinking agent such as a compound represented by formula II (R2 is a hydrocarbon or an acyl; R3 is an alkylene; R4 is H, a hydrocarbon or an acyl; (m)is a number of >=1, except the compound is the same compound as that represented by formula I and the defoaming agent represented by formula I.</p> |
