THERMAL RESPONSIVE MICROCAPSULE, THERMAL RECORDING MATERIAL AND MULTICOLOR THERMAL RECORDING MATERIAL USING THE MICROCAPSULE

摘要

PURPOSE: To obtain a thermal responsive microcapsule showing high color forming properties and excellent in storage properties by using a specific polyfunctional isocyanate compd. in the capsule wall of a microcapsule including a diazonium salt or an electron donating dye precursor. CONSTITUTION: The capsule wall of a microcapsule including a diazo compd. or an electron donating dye precursor in a thermal recording material of a printer is prepared from a polymer obtained by polymerizing an isocyanate compd. composed of an adduct of a polyhydroxyl compd. composed of a polyhydric phenol compd. having three or more hydroxyl groups in its molecule represented by either one of formulae I, III (R<1> and R<2> are a hydrogen atom or a methoxymethyl group, R<3> is a hydrogen atom or a methyl group, R<4> is a methyl group or a group represented by formula II, R<6> is a hydrogen atom or a phenyl group and R<7> and R<8> are a methyl group or the like) and difunctional isocyanate having two isocyanate groups in its molecule and a compd. having two active hydrogen atoms in its molecule.