A thermoreversible recording medium including a support, and a thermoreversible recording layer, which is disposed on the support, and contains a leuco dye, and a reversible color developer, wherein an average particle diameter of granules in the thermoreversible recording layer is 0.35 micrometers or smaller.

The present invention relates to thermochromic micro particles capable of stably implementing a high chromogenic property and a decolorization property and having an improved erasing property, thermal resistance, and chemical resistance, and a thermochromic ink composition, a writing apparatus, and a smart window using the same. The thermochromic micro particles comprise a core part including a phase change material and a dye, the phase change material including a phenol-based compound containing an aliphatic functional group having a carbon number of 6 or more; and a shell layer including a polymer resin.

The present invention relates to thermochromic micro particles capable of stably implementing a high chromogenic property and a decolorization property and having an improved erasing property, thermal resistance, and chemical resistance, and a thermochromic ink composition, a writing apparatus, and a smart window using the same. The thermochromic micro particles comprise a core part including a phase change material, a dye, and a developer, the phase change material including at least one selected from the group consisting of at least one chain hydrocarbon having a carbon number of 8 or more, a hydrated inorganic salt, alcohol having a carbon number of 3 or more, and polyalkyleneglycol; and a shell layer including a polymer resin.

The present invention relates to a coated paper article with an intermediate basecoat layer comprising high void fraction porous hollow sphere polymer particles (HSPs). HSPs with very small pore area density and high void fraction result in increased optical density at a given print energy in thermal printing applications.

A reversible recording medium according to an embodiment of the present disclosure includes: a recording layer including a coloring compound having an electron-donating property, a color developing/quenching agent having an electron-accepting property, a photothermal conversion agent, and a macromolecular material; and an ultraviolet absorbing layer provided on the recording layer, the macromolecular material including an organic material that has solubility of 20 wt % or more and 80 wt % or less at 25 C. or less and contains 0.5 wt % or less of chlorine atoms, fluorine atoms, and sulfur atoms in a molecule.

A color developer for a thermal recording layer includes: a compound of formula (I):

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; and an N-substituted amino acid derivative of formula (II): (R.sup.0X)Y(Z). The color developer is excellent in plasticizer resistance.

A thermochromic pigment composition including: (A) at least one electron-donor organic dye compound, (B) at least one electron-acceptor compound, and (C) at least one compound responding to the following formula (I), in which: R.sub.1 is H or a phenyl group, R.sub.2 is H or a phenyl group, and -n=1-8. The thermochromic pigment composition includes thermochromic pigment microcapsules ink compositions including such thermochromic pigment microcapsules, and writing instruments including such ink compositions.

A main purpose of the present invention is to provide a heat-sensitive recording medium that utilizes a chromogenic reaction between a dye precursor and a developer, wherein a colored image is tinged with a metallic luster so as to exhibit a gold metal color tone with a vivid appearance, or to provide a heat-sensitive recording medium exhibiting a yellow or gold metal color tone and a color tone different from the yellow or gold metal color tone, wherein the color optical density in each of the color tones is high, and a recording part has excellent color separation properties. The present invention provides a heat-sensitive recording medium comprising a heat-sensitive recording layer containing a dye precursor and a developer on a support, the dye precursor being a dye precursor which is colored to a yellow color tone, wherein: (a) the support has a metallic luster and provides a metallic luster to a surface of a base material not having a metallic luster; and/or (b) the dye precursor which is colored to a yellow color tone is a first dye precursor, and the heat-sensitive recording medium further contains a second dye precursor which is colored to a different color tone from the first dye precursor; the first dye precursor being a compound having a specific pyridine skeleton; and the second dye precursor: (b1) has a form of fine composite particles containing the second dye precursor and a polymer compound; or (b2) has a melting point of 200 C. or more.

A printable recording media containing a base substrate and a coating layer having a total solid content ranging from about 3 to about 65 weight percent by total weight of the coating composition and that includes from about 10 to about 90 weight percent of starch nanoparticles having a particle size ranging from about 40 to about 500 nm and from about 10 to about 90 weight percent of a water soluble divalent or multi-valent metal salt. Also described herein are a method for making the printable recording media and a method for producing printed images using the recording media.

A composition for forming a visually discernible color, the use of this composition for producing a heat-sensitive recording material, the corresponding heat-sensitive recording material includes a substrate and this composition, and a process for producing the heat-sensitive recording material.