with water a polymerization initiator usable in the present invention is not particularly limited as long as it is soluble in the solvent used examples of the polymerization initiators include 2 2 39 azobisisobutyronitrile 2 2 39 azobis 2 methylbutyronitrile 2 2 39 azobis 2 4 dimethylvaleronitrile 2 2 39 azobis 2 amidinopropane dihydrochloride and 2 2 39 azobis n n dimethyleneisobutylamidine the amount of the polymerization initiator ranges from 0 01 to 5 by weight based on the monomers the polymerization temperature which varies depending on the polymerization solvent ranges from 40 u00b0 to 90 u00b0 c and the polymerization time ranges from 1 to 7 hours the molecular weight is not particularly limited however from the viewpoints of the properties of the non woven fabrics to which the polymer is to be applied and the workability during the application the weight average molecular weight is preferably 10 000 to 1 500 000 particularly preferably 50 000 to 800 000 according to the present invention polymers soluble in tap water but insoluble in water containing at least 0 5 of a neutral inorganic salt comprising a monovalent ion can be easily obtained non woven fabrics and papers containing the polymer as the binder have sufficient strength and permeation to a body fluid when they are brought into contact with body fluid another characteristic feature of the present invention is that since the binder is dissolved in water in a flush toilet the non woven fabrics and papers are easily dispersed therefore the polymer of the present invention is widely usable as a binder or sheet for paper diapers sanitary goods surgical bandages and wet.