A color laser markable article includes a color laser markable layer provided on a support, the laser markable layer including an infrared absorbing compound; a leuco-dye; and an acid generating compound, wherein the acid generating compound has a structure according to Formulae (I) or (II): ##STR00001##
wherein R1 and R3 independently represent an optionally substituted alkyl group, an optionally substituted (hetero)cyclic alkyl group, an optionally substituted (hetero)aryl group, an optionally substituted aralkyl group, an optionally substituted alkoxy group, an optionally substituted (hetero)cyclic alkoxy group, or an optionally substituted (hetero)aryl group; R2, R4 and R5 independently represent an optionally substituted alkyl, an optionally substituted (hetero)cyclic alkyl group or an optionally substituted aralkyl group; and R1 and R2, R4 and R5, R3 and R4, and R3 and R5 may represent the necessary atoms to form a ring.

A color laser markable article includes a color laser markable layer provided on a support, the laser markable layer including an infrared absorbing compound; a leuco-dye; and an acid generating compound, wherein the acid generating compound has a structure according to Formulae (I) or (II): ##STR00001##
wherein R1 and R3 independently represent an optionally substituted alkyl group, an optionally substituted (hetero)cyclic alkyl group, an optionally substituted (hetero)aryl group, an optionally substituted aralkyl group, an optionally substituted alkoxy group, an optionally substituted (hetero)cyclic alkoxy group, or an optionally substituted (hetero)aryl group; R2, R4 and R5 independently represent an optionally substituted alkyl, an optionally substituted (hetero)cyclic alkyl group or an optionally substituted aralkyl group; and R1 and R2, R4 and R5, R3 and R4, and R3 and R5 may represent the necessary atoms to form a ring.

The present invention discloses a method and apparatus for imaging and cutting a label from a linerless label substrate 6, the substrate 6 comprising: a paper or polymeric film base layer; a colour change layer, incorporating a colour change compound operable to change colour in response to illumination by a laser 1; an adhesive layer; and a release layer adapted to have low adherence to the adhesive layer. The label substrate 6 is transported from a storage reel to an imaging area. At the imaging area, the label substrate 6 is selectively illuminated by laser 1 to form an image in the colour change layer. Subsequently, further laser illumination is used to cut the label substrate 6 thereby providing a single label for application to an object. The invention is characterised in that the laser spot size is varied for imaging and cutting.

A new leuco dye produces a yellow color while demonstrating also exceptional light and thermal stability under light.

A recording medium according to an embodiment includes a base material; a first color developing layer that is laminated on the base material, and absorbs light having a given wavelength to develop a color; a photothermal conversion layer that is laminated closer to an incident side of the light than the first color developing layer, transmits visible light, and absorbs the light for photothermal conversion; and a second color developing layer that is laminated closer to the incident side of the light than the first color developing layer, transmits visible light and the light, and develops a color by heat converted by the photothermal conversion layer.

A heat-sensitive recording material including a web-shaped substrate having a front side and an opposite reverse side, and at least one heat-sensitive recording layer on either or both of the sides of the web-shaped substrate. The heat-sensitive recording layer contains at least one dye precursor at least one salicylic acid derivative as a (color) developer reactive with this at least one dye precursor, and polyvinylpyrrolidone as auxiliary component augmenting the (color) developer the at least one salicylic acid derivative is 3,5-di(α-methylbenzyl)salicylic acid.

Heat-seal condition indicating packages include a first sealing substrate comprising a leuco dye and a second sealing substrate comprising a leuco dye developer. The packages may optionally include a leuco dye sensitizer which dissolves both the leuco dye and the leuco dye developer when melted. The packages further include a heat-seal produced between the first sealing substrate and the second seating substrate. The heat-seal comprises a reaction product of the leuco dye and the leuco dye developer. The reaction product may be colored, which may provide the heat-seal with a detectable optical characteristic. A magnitude of the optical characteristic may be proportion to the strength of the seal between the first and second seating substrates.

Heat-seal condition indicating packages include a first sealing substrate comprising a leuco dye and a second sealing substrate comprising a leuco dye developer. The packages may optionally include a leuco dye sensitizer which dissolves both the leuco dye and the leuco dye developer when melted. The packages further include a heat-seal produced between the first sealing substrate and the second seating substrate. The heat-seal comprises a reaction product of the leuco dye and the leuco dye developer. The reaction product may be colored, which may provide the heat-seal with a detectable optical characteristic. A magnitude of the optical characteristic may be proportion to the strength of the seal between the first and second seating substrates.

A label assembly including one or more dissolvable thermal direct adhesive labels and methods of assembly and use. According to one embodiment, each label includes a base layer, a thermal direct layer, an adhesive layer, and a barrier layer. The base layer, which has an upper surface and a lower surface, is water-dissolvable and may be made of a water-dissolvable paper. The thermal direct layer is positioned directly over the upper surface of the base layer and functions in the conventional manner to produce markings therein in response to heat. The adhesive layer is water-dissolvable and is positioned below the lower surface of the base layer. The barrier layer, which is positioned directly below the lower surface of the base layer and directly over the adhesive layer, serves to prevent migration of the adhesive layer through the base layer and into contact with the thermal direct layer.

Described are colour developers of formula (I) Ar.sup.1—SO.sub.2—NH—C.sub.6H.sub.4—SO.sub.2—C.sub.6H.sub.4—NH—CO—NH—Ar.sup.2 (I), a heat-sensitive recording material, comprising a carrier substrate and also a heat-sensitive, colour-forming layer comprising at least one colour former and at least one phenol-free colour developer, the at least one colour developer being the compound of formula (I), and a method for producing this heat-sensitive recording material.