Non-phenolic color developer and heat-sensitive recording material

A heat-sensitive recording material, comprising a carrier substrate and a heat-sensitive colour-forming layer, which contains at least one colour former and at least one phenol-free colour developer, wherein the at least one colour developer is the compound of formula (I):

• (Ar1—SO2—NH—)m—Y—(—NH—C(O)—NH—SO2—Ar2)n (I),
• wherein Y is at least one benzene group substituted (m+n) times, and Y is substituted in such a way that at least one Ar2—SO2—NH—C(O)—NH group is in the ortho position with respect to at least one Ar1—SO2—NH group, wherein Ar2 is an unsubstituted phenyl group or a monosubstituted phenyl group and, wherein Ar1 is an unsubstituted, substituted or monosubstituted phenyl group, or an unsubstituted or substituted 2-naphthy group, which is substituted with a C1-C5 alkyl, an alkenyl, an alkynyl, a benzyl, an RO, a halogen, a formyl, an ROC, an RO2C, a CN, an NO2, an R—SO2O, an RO—SO2, an R—NH—SO2, an R—SO2—NH, an R—NH—CO—NH, an R—SO2—NH—CO—NH, an R—NH—CO—NH—SO2 or an R—CO—NH group, wherein R is a C1-C5 alkyl, an alkenyl, an alkynyl, a phenyl, a tolyl or a benzyl group.