Antifoaming agent, antifoaming agent containing it and water-based coating composition

摘要

The purpose of the present invention is to provide a defoaming-property improver with which it is possible to suppress cissing, and to dramatically enhance defoaming properties, merely by compounding a hydrophobic compound with the improver. The present invention is a defoaming-property improver formed by the inclusion of a compound represented by formula 1 or a compound represented by formula 2. X is a residue obtained by removing a hydroxyl group from an alcohol condensate; Y is an oxygen atom or 1,4-dioxa-2-oxobutylene; OA is oxyalkylene; Z is a group represented by ‒R, ‒C(=O)‒R, ‒C(=O)‒NH‒R, or ‒CH2‒CH(‒OH)‒CH2‒R; R is alkyl, alkenyl, or aryl; S is a residue obtained by removing carboxyl hydrogen atoms from a (co)polymer having (meth)acrylic acid as an essential constituent monomer; M is a hydrogen atom, methyl, or ethyl; a is 0-20; b is 0-10; c is 1-16; d is 0-10; e is 0-10; and f is 2-10.