REVERSIBLE HEAT-SENSITIVE RECORDING MEDIUM

PROBLEM TO BE SOLVED: To provide a reversible heat-sensitive recording medium which has excellent dispersibility and dispersion stability of silica, and has stable glossiness, excellent color-sensitivity and repetition durability even when coated with a protective layer irrespective of the storage period of the dispersion obtained by dispersing silica.SOLUTION: In a reversible heat-sensitive recording medium having, on a substrate, a reversible heat-sensitive recording layer containing: an electron-donating coloring compound which is usually colorless or has a pale color; and a reversible electron-accepting compound forming a relatively color-developed state and an erased state by difference in heating temperature and/or cooling speed after heating, a protective layer containing at least silica and polyvinyl butyral is arranged on the reversible heat-sensitive recording layer, where the polyvinyl butyral has weight average molecular weight of 10,000 or more, and the added amount of the polyvinyl butyral is 0.5-5.0 mass% with respect to the protective layer.SELECTED DRAWING: None 【課題】シリカの分散性および分散安定性が良好であり、該シリカ分散により得た分散液の保管期間に関係なく保護層塗工しても、光沢が安定的で発色感度と繰り返し耐久性に優れた可逆性感熱記録媒体を提供する。【解決手段】支持体上に通常無色ないし淡色の電子供与性呈色性化合物と、加熱温度および／または加熱後の冷却速度の違いにより相対的に発色した状態と消去した状態を形成させる可逆性電子受容性化合物とを含有する可逆性感熱記録層を有する可逆性感熱記録媒体において、該可逆性感熱記録層上に少なくともシリカとポリビニルブチラールを含有する保護層を設け、該ポリビニルブチラールの重量平均分子量が１０，０００以上であり、かつ添加量が該保護層に対して０．５〜５．０質量％である事とする。【選択図】なし