Provided are an ink composition for writing instruments which has a good solubility of a coloring material in an ink solvent and which is less liable to cause bleeding and feathering on the written lines and is improved in a water resistance, and a coloring material used for preparing the above ink composition. The coloring material includes a material obtained by adding at least one selected from a leuco dye, a halochromic dye and a photochromic compound to a compound represented by the following Formula (I): ##STR00001##
The ink composition for writing instruments is characterized by containing the coloring material described above.

Provided are an ink composition for writing instruments which has a good solubility of a coloring material in an ink solvent and which is less liable to cause bleeding and feathering on the written lines and is improved in a water resistance, and a coloring material used for preparing the above ink composition. The coloring material includes a material obtained by adding at least one selected from a leuco dye, a halochromic dye and a photochromic compound to a compound represented by the following Formula (I): ##STR00001##
The ink composition for writing instruments is characterized by containing the coloring material described above.

Disclosed is a photochromic composition comprising a naphthopyran-based photochromic compound having a specific structure and an oligomer.

Disclosed is a photochromic composition comprising a naphthopyran-based photochromic compound having a specific structure and an oligomer.

Provided is an aqueous ink composition for a writing instrument which is excellent in storage stability of particles, such as pigments, a writing property with the passage of time, followability, and quality of the drawn lines, though having a low viscosity, as compared with aqueous ink compositions prepared by using conventional thickeners and gelling agents, such as xanthan gum. The ink composition for a writing instrument described above includes an aqueous ink composition for a writing instrument containing 0.05 to 1.5% by mass of an oxidized cellulose and having a limiting viscosity of 16 mPa.Math.s or less derived from Casson's equation, a viscosity value of 100 to 3000 mPa.Math.s at a shear rate of 3.83 s.sup.−1 and a viscosity value of 10 to 40 mPa.Math.s at a shear rate of 383 s.sup.−1.

Provided is an aqueous ink composition for a writing instrument which is excellent in storage stability of particles, such as pigments, a writing property with the passage of time, followability, and quality of the drawn lines, though having a low viscosity, as compared with aqueous ink compositions prepared by using conventional thickeners and gelling agents, such as xanthan gum. The ink composition for a writing instrument described above includes an aqueous ink composition for a writing instrument containing 0.05 to 1.5% by mass of an oxidized cellulose and having a limiting viscosity of 16 mPa.Math.s or less derived from Casson's equation, a viscosity value of 100 to 3000 mPa.Math.s at a shear rate of 3.83 s.sup.−1 and a viscosity value of 10 to 40 mPa.Math.s at a shear rate of 383 s.sup.−1.

A method for producing infra-red inert substrates, including molded polymeric articles, films, fibers and coatings and other organic and inorganic materials, by incorporating into the substrate or onto the surface of the substrate an effective amount of a dispersed bis-oxodihydroindolylen-benzodifuranone colorant. The thus obtained, also claimed substrates so produced are reflective and transparent to much of the near infra red radiation not reflected. There are multiple applications for cases of devices comprising electronic components, outdoor construction elements, outdoor furniture, automotive, marine or aerospace parts, laminates, artificial leather or textile materials, as well as in polychrome printing processes and optical fibers. The thus obtained substrates can also be subjected to laser welding. New bis-oxo-dihydroindolylen-benzodifuranone compounds are also claimed.

A method for producing infra-red inert substrates, including molded polymeric articles, films, fibers and coatings and other organic and inorganic materials, by incorporating into the substrate or onto the surface of the substrate an effective amount of a dispersed bis-oxodihydroindolylen-benzodifuranone colorant. The thus obtained, also claimed substrates so produced are reflective and transparent to much of the near infra red radiation not reflected. There are multiple applications for cases of devices comprising electronic components, outdoor construction elements, outdoor furniture, automotive, marine or aerospace parts, laminates, artificial leather or textile materials, as well as in polychrome printing processes and optical fibers. The thus obtained substrates can also be subjected to laser welding. New bis-oxo-dihydroindolylen-benzodifuranone compounds are also claimed.

Provided is an aqueous ink composition for writing instruments, having sufficient antibacterial and antifungal properties without hindering preservation stability and writing capability. The aqueous ink composition for writing instruments according to the present invention at least includes 0.001 mass % or greater and less than 0.1 mass % of a preservative, and 0.05 mass % or greater and less than 5 mass % of a straight-chain alkanediol selected from the group consisting of 1,2-pentanediol, 1,2-hexanediol, and 1,2-octanediol.

Provided is an aqueous ink composition for writing instruments, having sufficient antibacterial and antifungal properties without hindering preservation stability and writing capability. The aqueous ink composition for writing instruments according to the present invention at least includes 0.001 mass % or greater and less than 0.1 mass % of a preservative, and 0.05 mass % or greater and less than 5 mass % of a straight-chain alkanediol selected from the group consisting of 1,2-pentanediol, 1,2-hexanediol, and 1,2-octanediol.