The present disclosure concerns non-aqueous gel writing ink including a solvent, a coloring agent and a gelling agent, in which the gelling agent is a mixture of silica particles and of a fatty acid amide wax. It also concerns the process of preparation of the non-aqueous gel writing ink and the use of a mixture of silica particles and of a fatty acid amide wax, as a gelling agent in a non-aqueous gel writing ink. It finally concerns a writing instrument containing the ink according to the present disclosure.

The present disclosure concerns non-aqueous gel writing ink including a solvent, a coloring agent and a gelling agent, in which the gelling agent is a mixture of silica particles and of a fatty acid amide wax. It also concerns the process of preparation of the non-aqueous gel writing ink and the use of a mixture of silica particles and of a fatty acid amide wax, as a gelling agent in a non-aqueous gel writing ink. It finally concerns a writing instrument containing the ink according to the present disclosure.

An ink composition contains a carbon black and/or an organic pigment, water, a polysaccharide, two or more of diols, and particles of an acrylic resin. The two or more of diols include a first diol having from 5 to 7 carbon atoms and a second diol having from 1 to 4 carbon atoms, and a content of the first diol in the ink composition is 0.05 wt % or more.

An ink composition contains a carbon black and/or an organic pigment, water, a polysaccharide, two or more of diols, and particles of an acrylic resin. The two or more of diols include a first diol having from 5 to 7 carbon atoms and a second diol having from 1 to 4 carbon atoms, and a content of the first diol in the ink composition is 0.05 wt % or more.

An oil-based ink composition for a writing instrument, comprising a dye, an organic solvent and a phenolic compound of the following general formula (1): ##STR00001##
wherein R is each independently hydrogen or an alkyl group having 1 to 5 carbon atoms, R.sub.1 is any of an alkyl group having 1 to 5 carbon atoms, a halogenated alkyl group having 1 to 5 carbon atoms, a phenyl group, a hydroxyphenyl group, and an alkyl group having 1 to 5 carbon atoms substituted by a hydroxyphenyl group, and R.sub.2 is any of a halogenated alkyl group having 1 to 5 carbon atoms, a phenyl group, a hydroxyphenyl group, and an alkyl group having 1 to 5 carbon atoms substituted by a hydroxyphenyl group. The oil-based ink composition for a writing instrument can form handwriting having excellent water resistance in which no bleeding occurs on written surfaces of various materials with a dye retaining color development.

An oil-based ink composition for a writing instrument, comprising a dye, an organic solvent and a phenolic compound of the following general formula (1): ##STR00001##
wherein R is each independently hydrogen or an alkyl group having 1 to 5 carbon atoms, R.sub.1 is any of an alkyl group having 1 to 5 carbon atoms, a halogenated alkyl group having 1 to 5 carbon atoms, a phenyl group, a hydroxyphenyl group, and an alkyl group having 1 to 5 carbon atoms substituted by a hydroxyphenyl group, and R.sub.2 is any of a halogenated alkyl group having 1 to 5 carbon atoms, a phenyl group, a hydroxyphenyl group, and an alkyl group having 1 to 5 carbon atoms substituted by a hydroxyphenyl group. The oil-based ink composition for a writing instrument can form handwriting having excellent water resistance in which no bleeding occurs on written surfaces of various materials with a dye retaining color development.

Provided is an aqueous ink composition for a writing instrument with excellent stability of ink flow and the like, in which aggregation of a microcapsule pigment and clogging due to such aggregation are suppressed. The aqueous ink composition for a writing instrument includes a microcapsule pigment which includes inside, at least, a pigment and a medium of a fatty acid polyol ester. A melting point of the fatty acid polyol ester is preferably 40 C. or higher, and is preferably 70 C. or lower.

Embodiments of the present disclosure provides an ink composition for a writing instrument comprising a colorant and water, wherein the ink composition further comprises a thickener including polyethylene glycol or polypropylene glycol having a molecular weight between 200 and 1000 and an acrylic resin having an amine.

Embodiments of the present disclosure provides an ink composition for a writing instrument comprising a colorant and water, wherein the ink composition further comprises a thickener including polyethylene glycol or polypropylene glycol having a molecular weight between 200 and 1000 and an acrylic resin having an amine.

Provided is an aqueous ink composition for writing instruments, which enables desired colorfulness to be obtained easily. The aqueous ink composition for writing instruments according to the present invention contains: pigmented microspheres each having a matrix comprising water and a polymer, and a water-insoluble dye; and unpigmented microspheres.