A novel dispersant contains a specific acetylene glycol and/or a specific acetylene glycol ethoxylate in combination with a specific arylphenol compound. Even when added in a small amount, the dispersant rapidly disperses disperse dyes and pigments and moreover exhibits excellent wettability and antifoaming properties. Dispersions and ink compositions containing the dispersant are also disclosed.

A novel dispersant contains a specific acetylene glycol and/or a specific acetylene glycol ethoxylate in combination with a specific arylphenol compound. Even when added in a small amount, the dispersant rapidly disperses disperse dyes and pigments and moreover exhibits excellent wettability and antifoaming properties. Dispersions and ink compositions containing the dispersant are also disclosed.

The present invention provides: a highly practical and safe oil-based ink composition for a writing board, said composition being capable of imparting high mark-erasability and having excellent resistance to drying up; and a marking pen incorporating the same. Specifically, the present invention provides: an oil-based ink composition for a writing board, said composition containing a pigment, an organic solvent, a resin, and at least one compound selected from compounds represented by general formula (1) or (2); and a marking pen obtained by incorporating the oil-based ink composition for a writing board. (In the formulae, R.sup.1-R.sup.4 each represent a C6-18 alkyl group or a C2-18 and O2-10 alkoxypolyglycol group.) ##STR00001##

The present invention provides: a highly practical and safe oil-based ink composition for a writing board, said composition being capable of imparting high mark-erasability and having excellent resistance to drying up; and a marking pen incorporating the same. Specifically, the present invention provides: an oil-based ink composition for a writing board, said composition containing a pigment, an organic solvent, a resin, and at least one compound selected from compounds represented by general formula (1) or (2); and a marking pen obtained by incorporating the oil-based ink composition for a writing board. (In the formulae, R.sup.1-R.sup.4 each represent a C6-18 alkyl group or a C2-18 and O2-10 alkoxypolyglycol group.) ##STR00001##

A writing instrument may be capable of preventing dye deposition to a pen core and highly achieving both inhibition of ink discoloration due to the dye deposition and improved writing feeling without reducing writing performance. Such a writing instrument may be equipped with a pen core and loaded with a water-based ink composition, wherein the water-based ink composition contains colored resin particles formed by polymerization of a monomer comprising at least cyclohexyl (meth)acrylate, enclosing a basic dye, an oil-soluble dye or an acid dye, and further contains an anionic surfactant.

A thermochromic writing instrument including a writing body, storing a thermochromic ink therein, stored in a barrel; an operation body provided in the barrel to be operated to longitudinally move the writing body; a nib of the writing body configured to be capable of appearing from a front end of the writing instrument, wherein the writing instrument 1 further includes a friction unit, for rubbing handwriting in the thermochromic ink and capable of thermally changing the color of the handwriting by frictional heat generated at that time, and at least one clip body as the operation body, the friction unit 10 is provided at a rear end of the barrel, and the clip body is provided in an area other than the rear end of the barrel.

A thermochromic writing instrument including a writing body, storing a thermochromic ink therein, stored in a barrel; an operation body provided in the barrel to be operated to longitudinally move the writing body; a nib of the writing body configured to be capable of appearing from a front end of the writing instrument, wherein the writing instrument 1 further includes a friction unit, for rubbing handwriting in the thermochromic ink and capable of thermally changing the color of the handwriting by frictional heat generated at that time, and at least one clip body as the operation body, the friction unit 10 is provided at a rear end of the barrel, and the clip body is provided in an area other than the rear end of the barrel.

Provided are a dispersion of colored resin fine particles for an aqueous ink which has property of improving a drying property of the drawn lines in addition to the performances of a colorant such as a color developability, a weather resistance, and stability, and an aqueous ink composition for a writing instrument which is prepared by using the dispersion. The dispersion is characterized by comprising at least a vinyl monomer (A) containing an acidic functional group of a carboxyl group having solubility of 10% by mass or lower in water, an ester monomer (B) of acrylic acid or methacrylic acid with linear or cyclic alcohol having 2 to 18 carbon atoms, and a basic dye or an oil-soluble dye are dispersed in water. Also, the aqueous ink composition for a writing instrument is characterized by containing the dispersion, a water-soluble organic solvent and water.

Provided are a dispersion of colored resin fine particles for an aqueous ink which has property of improving a drying property of the drawn lines in addition to the performances of a colorant such as a color developability, a weather resistance, and stability, and an aqueous ink composition for a writing instrument which is prepared by using the dispersion. The dispersion is characterized by comprising at least a vinyl monomer (A) containing an acidic functional group of a carboxyl group having solubility of 10% by mass or lower in water, an ester monomer (B) of acrylic acid or methacrylic acid with linear or cyclic alcohol having 2 to 18 carbon atoms, and a basic dye or an oil-soluble dye are dispersed in water. Also, the aqueous ink composition for a writing instrument is characterized by containing the dispersion, a water-soluble organic solvent and water.

A writing, marking and/or drawing liquid for writing implements, especially for capillary pens, which has a viscosity of less than 50 mPas (Brookfield, 20 C., CPE-40 plate-cone), contains a resin mixture dissolved in a solvent matrix having at least one solvent. Wherein the resin mixture contains a first resin in the form of a modified resin ester and/or a dissolved polyester resin and a second resin in the form of a maleate resin and/or a rosin, especially a phenol-modified rosin. Additives are present in the form of at least one fluorosurfactant as wetter and at least one polyethersiloxane copolymer as glidant.