| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a defoaming agent which exhibits an excellent foam inhibition effect and an excellent defoaming effect even at low concentration and further to provide a method for producing paper and a method for clarifying waste water using the defoaming agent. <P>SOLUTION: The defoaming agent contains an oligoester compound shown by following formula (1), wherein R<SP POS="POST">1</SP>may be the same or different and shows a residual group formed by removing two hydroxyl groups from a polyol compound, respectively, R<SP POS="POST">2</SP>shows a residual group formed by removing a carboxyl group from a dicarboxylic acid, R<SP POS="POST">3</SP>and R<SP POS="POST">4</SP>may be the same or different and shows a residual group formed by removing a hydroxyl group from a carboxyl group of 8-36C high fatty acid, respectively. However R<SP POS="POST">3</SP>and R<SP POS="POST">4</SP>are not be hydrogen atoms at the same time, n denotes an integer of 1 or more and when n is 2 or more, R<SP POS="POST">1</SP>and R<SP POS="POST">2</SP>may be the same or different from each other. <P>COPYRIGHT: (C)2012,JPO&INPIT |
