Manufacture of decomposable microcapsule

PROBLEM TO BE SOLVED: To easily achieve decomposition under such conditions that used paper is treated, in a microcapsule prepared from a polyisocyanate, by a method wherein a bifunctional isocyanate for use in the manufacture of microcapsule contains one ester and/or amino group per mole in a principal chain. SOLUTION: A microcapsule for carbonless copying paper is manufactured from a polyisocyanate and a polyamine and in that case, a bifunctional isocyanate to be used in the manufacturing contains one ester and/or amino group per mole in a principal chain is used. And at that moment, an isocyanate mixture containing an isocyanate A containing a emulsifier is preferably used and in order to introduce the emulsifier, an isocyanato group, for example, is caused to react with a compound capable of forming salt and/or having hydrophilic function and as the compound, for example, dimethylpropionic acid, N,N-dimenthylethanolamine are used.