| 摘要 |
PROBLEM TO BE SOLVED: To provide a heat sensitive recording material, in which no coating defect such as streaks, unevenness or the like develops, which has a high transparency and, at the same time, in which no problem such as void and sticking develops and which is excellent in head matching properties, and its manufacturing method. SOLUTION: The transparent heat sensitive recording material is produced by providing a heat sensitive recording layer mainly made of a leuco dye, a developer and a binder resin on a support and, in addition, by providing a protective layer containing the resin on the heat sensitive recording layer. At this time, a protective layer coating liquid including a pigment dispersed with a circulating type horizontal sand mill is ultrasonically treated with an ultrasonic defoaming machine within the liquid temperature of 5 to 40 deg.C at an ultrasonic sound pressure value (Px) represented by formula (1): Px= Vm×10<-((> S<v+α)/20)> of 2×10<10> to 12×10<10> ×Pa, where Px (in μPa) is the sound pressure value, Vm (in V) is a voltage value, Sv (in dB) is a wave-receiving sensitivity value and α (in dB) is a correction value. |
