ANTISCALING AGENT

PURPOSE:To enable to effectively suppress the formation of silica scale in service water, by using the titled antiscaling agent containing an alkylene oxide chain-contg. compound selected from the group consisting of three kinds of compounds of water-soluble nonionic surfactants. CONSTITUTION:The antiscaling agent contains at least one alkylene oxide chain- contg. compound selected from the group consisting of compounds A represented by the formula (wherein x1-x4 are each number of 3-52, and y1-y4 are each number of 1-125), compounds B represented by the formula of HO-(C2H4O)l- (C3H6O)m-(C2H4O)n-H (wherein l+n and m are each integer of 1 or more) and compounds C represented by the formula of RO-(C2H4O)p-H (wherein R is a 8-22C alkyl or alkenyl group, and p is an integer of 1 or more). The molecular weight of the compound A is made at 900-27,000, that of the compound B is made at 2,000-12,000, and that of the compound C is made at 400-2,000. Using said antiscaling agent, the formation of silica scale in service water is effectively suppressed.