The present invention relates to method of manufacturing a tamper-proof medium for thermal printing, wherein a liquid treatment composition comprising at least one acid is deposited on a substrate which comprises a thermochromic coating layer comprising at least one halochromic leuco dye.

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.

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 reversible recording medium of an embodiment of the disclosure includes a support base, and a recording layer provided on the support base and reversibly changing between a recorded state and a deleted state. The recording layer includes a photothermal conversion material including one or more of a compound having a phthalocyanine skeleton, a compound having a squarylium skeleton, a compound having a cyanine skeleton including, in a molecule, one or both of a counter ion of SbF.sub.6, PF.sub.6, BF.sub.4, ClO.sub.4, CF.sub.3SO.sub.3 and (CF.sub.3SO.sub.3).sub.2N and a methine chain containing a five-membered ring or a six-membered ring, and an inorganic compound; a coloring compound having an electron-donating property; and a color developing/quenching agent having an electron-accepting property and including at least one salicylic acid compound represented by the general formula (1) and including a linear hydrocarbon group having 25 to 34 carbon atoms via a linking group containing an amide moiety.

The present invention relates to an N-(4-((4-(3-phenylureido)phenyl)sulfonyl)phenyl)benzenesulfonamide in the polymorphic form ω.sup.18.9, characterised by an x-ray powder diffractogram having the Bragg angles (2θ/CuK.sub.α) 10.9, 11.7, 14.6, 15.0, 15.8, 16.6, 17.6, 18.9, 19.4, 20.9, 21.2, 22.0, 23.3, 24.4, 24.7, 26.1, 27.4, 29.4, 34.2,

or in the polymorphic form α.sup.21.2, characterised by an x-ray powder diffractogram having the Bragg angles (2θ/CuK.sub.α) 8.7, 9.8, 10.8, 13.2, 13.9, 14.9, 15.2, 16.0, 17.4, 17.7, 18.7, 20.4, 21.2, 21.6, 22.3, 23.0, 23.3, 23.9, 24.4, 25.0, 25.8, 26.6, 28.1, 28.9, 29.4, 30.1, 30.6, 31.8, 34.5, 35.3, 35.6, 36.9, a method for production thereof, use thereof as a colour developer in a heat-sensitive recording material, and a heat-sensitive recording material comprising N-(4-((4-(3-phenylureido)phenyl)sulfonyl)phenyl)benzenesulfonamide in the polymorphic form ω.sup.18.9 or in the polymorphic form α.sup.21.2.

The invention relates to a self-adhesive, heat-sensitive recording material, comprising a carrier substrate, a heat-sensitive, color-forming layer that is applied on one side of the carrier substrate and contains at least a non-phenolic color developer in and at least one color former, a siliconized layer on the upper side of the heat-sensitive, color-forming layer that is applied on the carrier substrate, as well as an adhesive layer on the side of the carrier substrate facing away from the heat-sensitive, color-forming layer.

A recording medium includes a recording layer configured to be able to change a color-developed state by an external stimulus and a plurality of structures provided on the recording layer. The recording layer has a plurality of color-developing portions, and a pitch Δd′ between the color-developing portions and a width W of each of the color-developing portions satisfy a relationship of Δd′>W.

Provided is a thermosensitive recording medium being excellent in oil resistance among various performances required for the thermosensitive recording medium, and being further excellent in heat resistance, plasticizer resistance, and printing (recording) run-ability.

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 contains at least two kinds of urea compounds. The two kinds of urea compounds comprise the first urea compound being represented by the following general formula 1, and the second urea compound being represented by the following general formula 2.

##STR00001##

wherein R.sup.1 represents a substituted or unsubstituted alkyl group, aralkyl group or aryl group, and R.sup.2 represents a hydrogen atom or an alkyl group,

##STR00002##

wherein R.sup.4 to R.sup.8 represent a hydrogen atom, a halogen atom, a nitro group, an amino group, an alkyl group, an alkoxy group, an aryloxy group, and the like, and m represents an integer of 0 to 2.

A recording medium includes a support substrate and a recording layer provided on the support substrate. The recording layer contains a color-exhibiting compound having an electron-donating property, a color-developing agent having an electron-accepting property, and a matrix polymer. The color-developing agent contains a compound represented by a specific formula. The matrix polymer contains a polycarbonate resin.

A recording medium includes a support substrate and a recording layer provided on the support substrate. The recording layer contains a color-exhibiting compound having an electron-donating property, a color-developing agent having an electron-accepting property, and a matrix polymer. The color-developing agent contains a compound represented by a specific formula. The matrix polymer contains a polycarbonate resin.