Papierfabrik August Koehler Se

Koehler Paper Se

Kerstin Zieringer

Michael Horn

Timo Stalling

The invention relates to a color developer of the formula (I), wherein m and n independently of one another are ≥1, Aris an unsubstituted or substituted (hetero) aromatic radical, Aris an unsubstituted or substituted phenyl radical, and Y is at least one (m+n)-times substituted benzene or naphthalene group, and to a heat-sensitive recording material, comprising a supporting substrate and a heat-sensitive color-forming layer containing at least one color former and at least one phenol-free color developer, wherein the at least one color developer is the compound of the formula (I). The invention further relates to a method for producing said heat-sensitive recording material.

Heat-sensitive recording material

The invention relates to 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, characterised in that the at least one colour developer is the compound of formula (A), Ar(NH&#x2014;CO&#x2014;NH&#x2014;CO&#x2014;NH&#x2014;Ar)(A), wherein Ar is an unsubstituted or substituted phenyl or naphthyl group, Aris an unsubstituted or substituted phenyl, naphthyl, pyridyl, thiazolyl or benzothiazolyl group, and n is 1 or 2.

The invention relates to a compound of the formula (I) Ar(NHSOAr)l(SONHAr)(NHC(O)NHAr)(I), wherein l and m independently of one another are 0, 1, 2, 3, and/or 4 and the sum of l+m is equal to or more than 1, n is 2, 3, 4, or 5, Ar is a benzol group which is substituted (l+m+n) times, Aris an unsubstituted or substituted aromatic group, and Aris an unsubstituted or substituted phenyl group or a benzoyl group. The invention also 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 said color developer.

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Achern, Germany

Kerstin Zieringer