摘要 |
Problems with pressure-sensitive recording materials in very cold conditions, such as a slow rate of colour development and an unacceptable colour density, are overcome by using a mixture of 1-isopropylphenyl-2-phenylethane with diisopropylnaphthalene and/or partially hydrogenated terphenyl as a solvent for the colour former. The solution of the colour former in this solvent is encapsulated in microcapsules which are coated onto a sheet. A synthetic colour developer can be used. Tma-h |