| 摘要 |
PURPOSE:To obtain a water stopping agent containing a polyoxyethylene polyol (meth)acrylate to which a polymerization initiator is added as a main ingredient, having high safety and large gelling strength and capable of withstanding to long-term use and suitable for engineering works. CONSTITUTION:A polyoxyethylene triol having 1000 average molecular weight obtained by subjecting ethylene oxide to addition polymerization with glyceral is reacted with methacrylic acid, etc., in the presence of p-toluenesulfonic acid to afford a compound expressed by the formula (R1 is H or methyl; (n) is an integer of >=2; (r) is an integer of 3-8; R2 is polyol residue of >=triol), e.g. polyoxyethylene triolmethacrylate, and a polymerization initiator such as a redox based catalyst (e.g. ammonium persulfate-sodium thiosulfate) is added thereto and the resultant mixture is used as a main component to provide the objective water stopping agent having high safety and large gelling strength, capable of forming a gel strength-retaining body which can bear to use for a long period of time. |
