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 invention relates to a color developer of the formula (I), wherein m and n independently of one another are ?1, Ar.sup.1 is an unsubstituted or substituted (hetero) aromatic radical, Ar.sup.2 is 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. ##STR00001##

An offset printing process for manufacturing a laser markable packaging uses a laser markable offset ink and a laser markable varnish or a laser markable dispersion-lacquer in the process to provide a laser markable image or area on the packaging. The laser markable offset ink, offset varnish or offset dispersion-lacquer including a leuco dye and a metal free optothermal converting agent may be used in the offset printing process.

The invention relates to a heat-sensitive recording material, comprising a supporting substrate and a heat-sensitive color-forming layer, which contains at least one color former and at least one phenol-free color developer, characterized in that the at least one color developer is a compound of formula (I), wherein Ar is an aryl residue, a heteroaryl residue, or a benzyl residue and Y is an aryl residue, a heteroaryl residue, a benzyl residue, an aryloxy residue, a heteroaryloxy residue, a benzyloxy residue, an arylamino residue, a heteroarylamino residue, or a benzylamino residue. The invention further relates to a method for producing said heat-sensitive recording material. ##STR00001##

A method for the secure protection of a portion of the surface of an official document bearing markings, in which: a transparent security layer (17) is selected, the layer including at least one semi-transparent printed image including at least one transparent binder and at least one thermochromic pigment (14, 13, 12, 11); the semi-transparent printed image reveals at least one semi-transparent visible pattern in a first non-activated state at least a first temperature, such that the markings can be seen through the image, the pattern not being visible in a second activated state at least a second temperature different from the first temperature. A device for the secure protection of a portion of the surface of an official document and such an official document are also described.

An object of the invention is to provide a recording material and recording sheet having excellent color-developing performance, storage stability, etc. A recording material having good color-developing performance and storage stability may be obtained by using a specific compound having a benzhydrol skeleton as an additive in a recording material employing color development through a reaction between a color former and a color-developing agent.

Provided are a packaging sheet and a packaging container where it is unnecessary to paste a printed label and disappearance or color development due to friction or the like after thermal printing do not occur. The packaging sheet includes a heat seal layer 10 for thermally welding by heating, a heat-sensitive layer 40 including a color developing material that develops a color by heating, and a base material layer 70 that secures the strength and protects the heat-sensitive layer 40. The heat seal layer 10, the heat-sensitive layer 40, and the base material layer 70 are provided in this order from a back surface side in a thickness direction. The packaging sheet is transparent before the heat-sensitive layer 40 develops the color.

The present invention relates to thermal recording materials comprising (in order): a support (base) layer; one or more undercoat layers; a thermal layer (thermosensitive coloring layer); and one or more protective layers, wherein the thermal recording material contains an aminocarboxylic and/or phosphorus-based chelating agent.

The thermal (thermosensitive) recording materials of the invention show enhanced plasticizer resistance and/or preprint uniformity.

The invention relates to a heat-sensitive recording material, comprising a carrier substrate and at least one heat-sensitive thermal reaction layer, which is applied to at least one side of the carrier substrate and contains at least one fluoran color former, at least one color developer, at least one melting aid, and optionally typical additives, such as lubricants, stabilizers (anti-aging agents), and/or pigments, characterized in that the color developer is dodecyl gallate and the melting aid is an ethylene bis fatty acid amide of formula (I), wherein R.sub.1 and R.sub.2 are CH.sub.3(CH.sub.2).sub.mCH.sub.2 with m=13 and/or 15. The invention further relates to a method for producing said recording material.

##STR00001##

The invention relates to a heat-sensitive recording material. A heat-sensitive recording material, comprising a carrier substrate and a heat-sensitive, color-forming layer that contains at least one color former and at least one phenol-free color developer, is characterized in that said at least one color developer is a compound of formula (I) where Ar.sub.1 and Ar.sub.2 are a phenyl group and/or a C.sub.1-C.sub.4-alkyl substituted phenyl group. The invention also relates to a method for producing this heat-sensitive recording material and to the use, in a heat-sensitive recording material, of the color developer of formula (I) that is present in said heat-sensitive, color-forming layer. ##STR00001##