| 摘要 |
PURPOSE:To ensure excellent thermal response and storage stability and prevent background fog from occurring easily by adding one kind or two kinds or more of compound selected from diphenyleneoxide derivatives at melting points of 50 to 200 deg.C to a thermosensitive color development layer. CONSTITUTION:Diphenyleneoxide derivatives have a lower melting point than those of leuco dye and organic acid materials or either one of them. The derivatives are also capable of dissolving leuco dye and/or organic acid material and cause either one or both of them to be dissolved and demonstrate the action to promote reaction of these two. That is, their melting point needs to be within the range of 50 to 200 deg.C so that the action as a color development promoter is demonstrated. The diphenyleneoxide should preferably be as expressed by a formula (1). The substituted group R is an alkyl group, an alkoxy group, a substituted alkyl group, an unsaturated or cycloalkyl group. If substituted groups R are present, these may be the same as or different from the other. |
