SCALE PREVENTING AGENT FOR CIRCULATING COOLING WATER SYSTEM

摘要

PURPOSE:To obtain a scale preventing agent for circulating cooling water system which has both the scale preventing effect and the anticorrosion effect, by polymerizing the acrylic compounds under the presence of the long-chain alkane thiol and using when necessary the oligomer which is obtained through the hydrolysis. CONSTITUTION:The monomer[such as (meth)acrylic acid or its Na salt] shown in FormulaI[wherein, R1 represents a hydrogen atom or a methyl group, and X respresents -COOH, COO-M+(M+ donotes a monovalent cation), -CONH2, -C=M or -COOR2(R2 denotes a 1-4C alkyl group optionally containing a hydroxyl group)]is polymerized with use of a radical polymerization starting agent and under the presence of the long-chain alkane thiol (such as octane thiol) shown in formula II (wherein, R3 represents a 8-20C alkyl group). In this case, 1-30wt% (5-20wt% preferable) long-chain alkane chiol is used to the monomer. A polymer thus obtained is directly used as a scale preventing agent. In case the (meth)acrylic acid (chloride) in the polymer is =50mol%, thehydrolysis is carried out with use of a monovalent strong basic compound like NaOH, etc. so that the COO content is set =50mol%.