The presently claimed invention relates to a color developer, a process for its manufacture and its use as a component in heat sensitive recording material. The heat sensitive recording material is useful for thermographic printing.

A heat-sensitive recording material having i) a supporting substrate and ii) a heat-sensitive recording layer, where the heat-sensitive recording layer comprises a colour former and a colour developer mixture and the colour developer mixture comprises a) N-[2-(3-phenylureido)phenyl]benzenesulfonamide (compound of the formula (I)), where the compound of the formula (I) is in a crystalline form having an absorption band at 3401 20 cm 1 in the IR spectrum, and b) N-(4-methylphenylsulfonyl)-N-(3-(4-methylphenylsulfonyloxy)phenyl) urea (compound of the formula (II)), where the mass ratio between the compound of the formula (I) and the compound of the formula (II) is 0.5:99.5 to 35:65 or 99.5:0.5 to 65:35.

Provided is a thermosensitive recording medium, which is excellent in color developing property, especially excellent in bar code readability, under severe environment, further, excellent in resistance to discoloration under severe environment. That is a thermosensitive recording medium having a thermosensitive recording layer comprising a colorless or pale colored electron donating leuco dye and an electron accepting color developing agent on a substrate, wherein the thermosensitive recording layer comprises, as the electron accepting color developing agent, a specific sulfone compound and a phenolic compound in a specific ratio, wherein the phenolic compound contains two or more hydroxyl groups and two or more diphenylsulfone backbone but contains neither urethane bond nor urea bond. The thermosensitive recording layer optionally may further comprise a specific urea-urethane-based compound.

A heat-sensitive recording material including a substrate, a heat-sensitive recording layer which includes N-(4-methylphenylsulfonyl)-/V-(3-(4-methylphenylsulfonyloxy)pheny-purea and/or N42-(3-phenylureido)phenyl]benzol sulfonamide, and an intermediate layer which is arranged between the substrate and the heat-sensitive recording layer and which includes calcined aluminum silicate, and a method for producing a heat-sensitive recording material and to the use of calcined aluminum silicate in an intermediate layer of a heat-sensitive recording material.

A thermosensitive recording material comprising a support; an insulating layer that includes a porous polymeric pigment; and an image-forming layer.

A thermochromic composition including a dye molecule; a matrix, wherein the matrix comprises a material having a defined melting point; and an optional developer. A process for preparing a thermochromic composition, including providing a dye; heating a matrix above its melting point; adding the heated matrix to the dye until the dye dissolves in the matrix; optionally, adding a developer; wherein the thermochromic composition exhibits a first color at a first temperature and a second color at a second temperature; wherein the first color and the second color are different; and wherein the first temperature and the second temperature are different.

In the present invention, there is provided a use of 1,1,1-tris(4-hydroxyphenyl)ethane in a composition in the formation of an image on a substrate having said composition applied thereon, wherein the image is formed upon exposure of the composition to NIR or IR radiation, and wherein the image is capable of being retained on the substrate for at least 1 day under conditions of at least 50% relative humidity. The present invention is further directed towards compositions comprising 1,1,1-tris(4-hydroxyphenly)ethane, in addition to substrates, methods of forming an image and printing processes comprising said compositions.

A recording material and a recording sheet having excellent color-developing performance and storage stability and particularly having excellent heat-resistance of background. The recording material contains a color former (A), a compound represented by formula (I) (B), and a compound represented by formula (II) (C).

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The invention relates to a color developer of formula (I), (Ar.sup.1SO.sub.2NH-)m-Y(NHC(O)NHSO.sub.2Ar.sub.2)n (I), wherein Ar.sup.1 is an unsubstituted or substituted aromatic moiety, Ar.sup.2 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 Ar.sub.2SO.sub.2NHC(O)NH group is in ortho-position with respect to at least one Ar.sup.1SO.sub.2NH 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.

Developing agent precursors and laser markable compositions including such developing agent precursors.