Abstract: The present invention provides a heat sensitive recording material, including a substrate and a heat sensitive recording layer thereon incorporating a colorless or light-colored basic dye and a color acceptor reactive with the dye to form a color when contacted therewith, the recording material also including 1-(4-methoxyphenoxy)-2-(2-methylphenoxy)ethane in the heat sensitive recording layer.

Abstract: A heat sensitive recording material comprising a substrate and a recording layer thereon incorporating a colorless or light-colored basic dye and a color acceptor reactive with the dye to form a color when contacted therewith, the recording material being characterized in that, as the color acceptor is used at least one compound selected from the group consisting of 4-hydroxy-4'-isopropyloxydiphenylsulfone, 4,4'-(1,3-dimethylbutylidene) bisphenol, 4,4'-(1-phenylethylidene)bisphenol, 4,4'-(p-phenylenediisopropylidene)bisphenol and 4,4'-(m-phenylenediisopropylidene) bisphenol, and to the recording layer is added at least one of a heat-fusible substance represented by the formula [I] ##STR1## wherein X is hydrogen atom, halogen atom, C.sub.1.about.4 alkyl or C.sub.1.about.4 alkoxy.

Abstract: In a heat-sensitive recording material incorporating a colorless or pale-colored basic dye and a color acceptor which is reactive with the basic dye to form a color when contacted therewith, the recording material characterized in that at least one compound represented by the formula [I] is contained in a heat-sensitive recording layer ##STR1## wherein X is --O-- or --COO--, R.sub.1 to R.sub.4 are each hydrogen atom, alkyl having 1 to 8 carbon atoms, aryl having 6 to 10 carbon atoms, aralkyl having 7 to 9 carbon atoms, chlorine atom, acetyl, propionyl, methoxy, methylthio, methoxycarbonyl, cyano, nitro or cyclohexenyl, substituents R.sub.1 and/or R.sub.2 or substituents R.sub.3 and R.sub.4 may link together to form aromatic ring(s), n is an integer of 1 to 10.

Abstract: In a heat-sensitive recording material incorporating a colorless or pale-colored basic dye and a color acceptor which is reactive with the dye to form a color when contacted therewith, the recording material characterized in that the color acceptor comprises at least one compound represented by the formula ##STR1## wherein R.sub.1, R.sub.2, R.sub.3 and R.sub.4 are each a hydrogen atom, alkyl having 1 to 8 carbon atoms, aryl or aralkyl, provided that R.sub.1 and R.sub.2, as well as R.sub.3 and R.sub.4, are not hydrogen at the same time.