DISPERSANT, COATING LIQUID COMPOSITION, AND THERMAL RECORDING MEDIUM

To provide a dispersant capable of dispersing a thermosensitive coloring component such as a leuco dye, a developer, or a sensitizer to a desired particle size within a shorter time, a coating liquid composition for forming a thermosensitive recording layer containing a heat-sensitive color component and a dispersant, and a thermal recording medium having a thermal recording layer formed on a substrate with the coating liquid.SOLUTION: There is provided a dispersant for at least one thermosensitive coloring component selected from the group consisting of leuco dyes (A), color developers (B), and sensitizers (C), wherein the dispersant contains an alkali-neutrarized salt of a copolymer (D) satisfying the following conditions. (1) A copolymer (D-1) of monomers made of (meth)acrylic acid and (meth) acrylic acid ester (D-1), and/or, a copolymer (D-2) of monomers made of (meth)acrylic acid and (meth)acrylic acid esters and styrenes, (2) an acid value is 40 to 400 mgKOH/g, and (3) a weight-average molecular weight is 3,000 to 30,000.SELECTED DRAWING: None 【課題】ロイコ染料、顕色剤、増感剤等の感熱発色成分を従来に比べ、より短時間で所望の粒子径まで細かく分散可能な分散剤、感熱発色成分と分散剤とを含む感熱記録層形成用の塗工液組成物、及び支持体上に前記塗工液で形成された感熱記録層を有する感熱記録体を提供する。【解決手段】ロイコ染料（Ａ）、顕色剤（Ｂ）、増感剤（Ｃ）の群から選ばれる少なくとも１種の感熱発色成分の分散剤であって、該分散剤が、以下の条件を満足する共重合体（Ｄ）のアルカリ中和塩を含むことを特徴とする分散剤。（１）（メタ）アクリル酸と（メタ）アクリル酸エステル類とからなるモノマーの共重合体（Ｄ－１）、及び／又は、（メタ）アクリル酸と（メタ）アクリル酸エステル類とスチレン類とからなるモノマーの共重合体（Ｄ－２）、である（２）酸価が４０～４００ｍｇＫＯＨ／ｇである（３）重量平均分子量が３，０００～３０，０００である【選択図】なし