The composition according to claim 3, wherein said at least one nitrogen organic compound is selected from the group consisting of reaction products of ethylene urea and formaldehyde, reaction products of ethylene thiourea and formaldehyde, and 1,3,5-triazine derivatives represented by the formula: ##STR17## wherein X is morpholino or piperidino, Y is a divalent group of piperzine, and n is an int