| 摘要 |
PURPOSE:To prevent a dust application to a thermal head to obtain an image having a superior dot reproducibility and a high sharpness, by incorporating specific polynorbornene particles in a thermal recording layer. CONSTITUTION:A thermal recording medium has a thermal recording layer containing a colorless or light-colored color forming substance and a color developer coloring the color forming substance under heat. In the thermal recording layer, polynorbornene particles shown by a formula I are incorporated. The polynorbornene particles in particle form are obtained by a method in which a norbornene is synthesized by the Diels-Alder reaction of ethylene and cyclopentadiene and this norbornene monomer is ring-opening polymerized. The remarkably porous structure and rapid hot melt substance absorptivity of the polynorbornene particles produce remarkable effects on the improvement of image sharpness, dot reproducibility, and head running properties in a thermal recording. |
