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.

There is disclosed a heat-sensitive recording material including an undercoat layer formed on one surface of a support and a heat-sensitive recording layer formed on the undercoat layer. The heat-sensitive recording layer contains a leuco dye and a coloring agent. The undercoat layer contains hollow particles and a binding resin. A maximum particle diameter (D100) of the hollow particles is 10 to 30 μm. A particle diameter (D50) of the hollow particles at cumulative 50 volume % is 4.0 to 15 μm. A ratio D100/D50 of the maximum particle diameter (D100) of the hollow particles to the particle diameter (D50) of the hollow particles at cumulative 50 volume % is 1.8 to 3.0. A volume percentage of the hollow particles having particle diameters of 2.0 μm or less is 1% or less.

Disclosed is a heat-sensitive recording material comprising an undercoat layer and a heat-sensitive recording layer formed in this order on a support, the undercoat layer containing hollow plastic particles and a binder, the heat-sensitive recording layer containing a leuco dye and a developer, and the heat-sensitive recording material having an elastic modulus of 200 N/mm.sup.2 or less as measured by a nanoindentation method.

The present invention relates to pigments which comprise niobium-doped titanium dioxide as well as a layer encapsulating the niobium-doped titanium dioxide, to polymer materials containing same and to the use of said pigments as laser absorbing additive in products comprising at least one polymer material and said encapsulated niobium-doped titanium dioxide containing pigments.

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.

The present invention relates to pigments which comprise niobium-doped titanium dioxide as well as a layer encapsulating the niobium-doped titanium dioxide, to polymer materials containing same and to the use of said pigments as laser absorbing additive in products comprising at least one polymer material and said encapsulated niobium-doped titanium dioxide containing pigments.

Ink formulations and methods of using the same in laser-imaging are provided. An ink formulation can comprise a graphene-based component, a colour change agent, a binder, and a solvent. Substrates, coatings, and articles comprising a graphene-based component are also provided, and laser marking can be brought about by an ablation or direct charring process.