Abstract: Use of N-(p-toluenesulfonyl)-N?-(3-p-toluenesulfonyl-oxy-phenyl)urea with an X-ray diffraction pattern with Bragg angles (2?/CuK?) of 10.3, 11.0, 12.9, 13.2, 15.4, 17.1, 18.0, 18.2, 19.4, 20.0, 20.7, 21.2, 23.0, 24.9, 25.3, 26.5, 26.8, 27.5, 30.7, 32.7 as a colour developer in a heat-sensitive recording material comprising a carrier substrate, a heat-sensitive colour-forming layer which is applied to one face of the carrier substrate and which contains at least one non-phenolic colour developer and at least one colour former, and an adhesive layer and/or a coating in order to allow rear-face printing using conventional printing methods on the carrier substrate face facing away from the heat-sensitive colour-forming layer, so as to limit the loss of image density and/or the relative print contrast and/or the reduction of the area-based colour developer quantity, wherein, with a value of ?1.

Abstract: The invention relates to a color developer of formula (I), (Ar1—SO2—NH—)m-Y—(—NH—C(O)—NH—SO2—Ar2)n (I), wherein Ar1 is an unsubstituted or substituted aromatic moiety, Ar2 is an unsubstituted or substituted phenyl moiety, Y is at least an (m+n)-times substituted benzene group or naphthalene group, and Y is substituted in such a way that at least one Ar2—SO2—NH—C(O)—NH group is in ortho-position with respect to at least one Ar1—SO2—NH group. The invention further relates to a heat-sensitive recording material, comprising a carrier substrate and a heat-sensitive color-forming layer, which contains at least one color former and at least one phenol-free color developer, the at least one color developer being the compound of formula (I). The invention further relates to a method for producing said heat-sensitive recording material.

Abstract: The invention relates to a color developer of formula (I), (Ar1—SO2—NH-)m-Y—(—NH—C(O)—NH—SO2—Ar2)n (I), wherein Ar1 is an unsubstituted or substituted aromatic moiety, Ar2 is an unsubstituted or substituted phenyl moiety, Y is at least an (m+n)-times substituted benzene group or naphthalene group, and Y is substituted in such a way that at least one Ar2—SO2—NH—C(O)—NH group is in ortho-position with respect to at least one Ar1—SO2—NH group. The invention further relates to a heat-sensitive recording material, comprising a carrier substrate and a heat-sensitive color-forming layer, which contains at least one color former and at least one phenol-free color developer, the at least one color developer being the compound of formula (I). The invention further relates to a method for producing said heat-sensitive recording material.