A glittering writing/drawing material composition includes a solvent, a lustrous particle having metallic luster and dispersed in the solvent, and at least one dye dissolved in the solvent. A hue difference between a first hue and a second hue is 108° or less in a hue circle in a Munsell color system, where the first hue is measured on the lustrous particle in a solid state with a spectrocolorimeter, and the second hue is measured on a liquid composition obtained by removing the lustrous particle from the glittering writing/drawing material composition and applied on a white wood-free paper with the spectrocolorimeter. The lustrous particle has a coverage of 1.0% or more and 70.0% or less on a surface layer of a drawing object formed by the glittering writing/drawing material composition.

A glittering writing/drawing material composition includes a solvent, a lustrous particle having metallic luster and dispersed in the solvent, and at least one dye dissolved in the solvent. A hue difference between a first hue and a second hue is 108° or less in a hue circle in a Munsell color system, where the first hue is measured on the lustrous particle in a solid state with a spectrocolorimeter, and the second hue is measured on a liquid composition obtained by removing the lustrous particle from the glittering writing/drawing material composition and applied on a white wood-free paper with the spectrocolorimeter. The lustrous particle has a coverage of 1.0% or more and 70.0% or less on a surface layer of a drawing object formed by the glittering writing/drawing material composition.

There is a thermochromic ink composition having core-shell microcapsules, an aqueous dispersion medium and a decolorization agent.

There is a thermochromic ink composition having core-shell microcapsules, an aqueous dispersion medium and a decolorization agent.

Provided is aqueous ink composition for a writing instrument, which contains water and microspheres having a water-insoluble dye and a matrix constituted from a polymer wherein the water-insoluble dye is higher densely present in the inner part of the matrix than at the surface of the matrix, and at least one of the following (a) and (b) is satisfied: (a) the circularity coefficient of the microspheres, as measured by image analysis, is 0.6-1.0, and (b) the 10% strength of the microspheres, as determined in a micro-compression test, is 5-30 MPa.

An ink composition for a reversibly thermochromic stamp including a reversibly thermochromic microencapsulated pigment encapsulating a reversibly thermochromic composition including: Component (A): an electron-donating color-developing organic compound, Component (B): an electron-accepting compound, and Component (C): a reaction medium causing reversibly an electron transfer reaction between the Component (A) and the Component (B) in a specific temperature range, water and a thickener.

An ink composition for a reversibly thermochromic stamp including a reversibly thermochromic microencapsulated pigment encapsulating a reversibly thermochromic composition including: Component (A): an electron-donating color-developing organic compound, Component (B): an electron-accepting compound, and Component (C): a reaction medium causing reversibly an electron transfer reaction between the Component (A) and the Component (B) in a specific temperature range, water and a thickener.

This oil-based ink composition for writing implements contains a colorant, a resin, an organic solvent, and fluorine-based resin particles, the average particle size of the fluorine-based resin particles being at least 0.1 μm and less than 1.0 μm when measured by a dynamic light scattering method.

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 corresponding to the following formula (I): in which: X is 0 or a single bond, Z is COO or OCO, R.sub.1 is O-alkyl or (CH.sub.2).sub.mCH.sub.3—R.sub.2 is OCO(CH.sub.2).sub.nCH.sub.3 or H, —y=0-3, —m=12-18; —p=8-18, and on the condition that, when X is 0, y is other than 0. The thermochromic pigment composition are also useable in thermochromic pigment microcapsules ink compositions including the thermochromic pigment microcapsules, and writing instruments including the ink compositions.

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 corresponding to the following formula (I): in which: X is 0 or a single bond, Z is COO or OCO, R.sub.1 is O-alkyl or (CH.sub.2).sub.mCH.sub.3—R.sub.2 is OCO(CH.sub.2).sub.nCH.sub.3 or H, —y=0-3, —m=12-18; —p=8-18, and on the condition that, when X is 0, y is other than 0. The thermochromic pigment composition are also useable in thermochromic pigment microcapsules ink compositions including the thermochromic pigment microcapsules, and writing instruments including the ink compositions.