Abstract: The present invention is an aqueous ink composition for ball-point pen comprising an aqueous ink mixture containing at least a pigment or colored polymer emulsion, a dispersant, a water-soluble organic solvent and water, and a compound of the general formula (1). Examples of such ink compositions include a sodium salt of polyoxyethylene alkyl ether phosphate monoester a sodium salt of polyoxyethylene alkyl ether phosphate diester, a triethanolamine salt of polyoxyethylene alkylphenyl ether phosphate monoester, triethanolamine salt of polyoxyethylene alkylphenyl ether phosphate diester. The aqueous ink composition provides a lubricity effect of rotating a ball smoothly when it is used for a ball-point pen.

Abstract: An aqueous ball point ink composition comprising a key aqueous ball point ink composition comprising coloring materials consisting of (pigment and pigment dispersant) and/or precolored emulsion resin, water-soluble organic solvent, pseudoplastic imparting agent and water and cross-linked polyacrylate salt in a proportion of about 0.05-0.5% by weight based on the amount of said key aqueous ball point ink composition.

Abstract: An aqueous ink is provided which comprises a coloring agent, a water-soluble solvent and water, where the amount of gas dissolved therein is less than the amount of gas present at the situation level. Where the aqueous ink composition is used for a writing instrument of ink-free type having a confined ink chamber structure, the writing instrument rarely causes ink leakage and writing defects such as uneven ink density and skips in a drawn line, even if it is allowed to stand at a high temperature or to stand for a long time.

Abstract: An aqueous ink composition is provided which includes an aqueous mixture containing at least a coloring agent, a pigment dispersant, a water-soluble organic solvent and water, and an organic white pigment of an alkylene-bis-melamine derivative represented by the general formula (1): ##STR1## wherein R represents a hydrogen atom, a lower alkyl group having 1 to 4 carbon atoms or an alicyclic group; R1, R2, R3 and R4 are the same or different, each representing a hydrogen atom or a lower alkyl group having 1 to 4 carbon atoms; R1 and R2, or R3 and R4 may form a heterocyclic group together with a nitrogen atom; and X represents a lower alkylene group having 2 to 3 carbon atoms. The aqueous ink composition is particularly useful for writing instruments of direct ink supply type and of wick type.

Abstract: An aqueous ink composition for ball-point pen is provided which includes an aqueous ink mixture containing at least a coloring agent, a dispersant, a water-soluble organic solvent and water, and a compound of the general formula (1): ##STR1## wherein R1 and R2 represent OH and/or HO(CH.sub.2 CH.sub.2 O)n and/or ##STR2## where Y is CmH2m+1 (m is an integer of not larger than 4); and X represents an alkali metal salt, amine salt or alkanolamine salt. The aqueous ink composition is excellent in lubricity, wear resistance of ball seat, writing touch and long-term stability, and is less liable to feather on paper.