| 摘要 |
PURPOSE:To prevent abrasion of a thermal head, by blending a copolymer of styrene-methacrylic acid in a thermal color-developing layer. CONSTITUTION:Styrene and methacrylic acid are copolymerized in a ratio of about 1:0.1-1:1 to give a copolymer having the molecular weight of about 10,000-200,000. Fine particles of this copolymer having a particle size of 0.05- 20mu is blended with main color-developing components consisting of a color- developing material which is colorless or light-colored usually, and an organic acid material which develops the color of said color-developing material by heat, a binder and additives of various kind, whereby a fluid for forming a thermal color-developing layer is prepared. The content of the styrene-methacrylic acid copolymer in the thermal color-developing layer corresponds to those of inorganic filler powder and organic resin powder, preferably, 5-60wt% of the total weight of the thermal color-developing layer. The heat-sensitive coating fluid containing the styrene-methacrylic acid copolymer is applied in an amount of 8-15g/m<2> on a support such as paper, whereby the thermal color-developing layer is formed. |
