The present disclosure concerns a writing ink composition comprising: (a) at least one film-forming elastomeric polymer wherein the film-forming elastomeric polymer (a) is an homopolymer or copolymer of polyurethane, (b) at least one polyether-modified polysiloxane, (c) at least one dye, (d) at least one pigment, and (e) water.

The disclosure also concerns a method for preparing such a writing ink composition. A writing instrument comprising such a writing ink composition, and a method for writing on a writing porous substrate, are also part of the disclosure. Finally, the disclosure aims at a writing porous substrate coated with a writing ink composition according to the disclosure.

Disclosed herein are a water-based ink composition for writing instruments excellent not only in handwriting fastness, such as handwriting water resistance, and dispersion stability but also in various properties such as dry-up resistance and handwriting density and a writing instrument using the same. The water-based ink composition for writing instruments contains a self-dispersible pigment, α-glucan or an α-glucan derivative, and water. The writing instrument contains the water-based ink composition for writing instruments. Also disclosed herein is a cartridge ink for writing instruments containing the water-based ink composition for writing instruments.

Dry erase ink formulations containing a resin, a pre-assembled colorant, and a solvent, wherein the dry erase ink formulation has a surface tension of at least 25 dynes per centimeter, and writing instruments including a dry erase ink formulation are provided herein.

Dry erase ink formulations containing a resin, a pre-assembled colorant, and a solvent, wherein the dry erase ink formulation has a surface tension of at least 25 dynes per centimeter, and writing instruments including a dry erase ink formulation are provided herein.

The present invention concerns a washable aqueous ink composition comprising: a) at least one salt of monocarboxylic or polycarboxylic acid with from 3 to 8 carbon atoms, 5b) at least one salt of polyacrylic acid, c) at least one dye. It also concerns a writing instrument comprising it and the use of the association of a) at least one salt of monocarboxylic or polycarboxylic acid with from 3 to 8 carbon and b) at least one salt of polyacrylic acid, to improve the washability 10 and/or vividness of the shades of a washable aqueous ink composition

There is a process for preparing in situ an aqueous gel ink with variable color having the following steps: (i) preparing a gel-based matrix of aqueous ink comprising a reducing agent, (ii) adding a solution of metallic salts, (iii) adding iron powder to obtain an aqueous gel ink with variable color, wherein the steps (ii) and (iii) can be interchanged. There also is an aqueous gel ink with variable color obtained according to the process of the disclosure, having a reducing agent, metallic nanoparticles and iron powder. There further is a writing instrument having an aqueous gel ink with variable color according to the disclosure.

There is a process for preparing in situ an aqueous gel ink with variable color having the following steps: (i) preparing a gel-based matrix of aqueous ink comprising a reducing agent, (ii) adding a solution of metallic salts, (iii) adding iron powder to obtain an aqueous gel ink with variable color, wherein the steps (ii) and (iii) can be interchanged. There also is an aqueous gel ink with variable color obtained according to the process of the disclosure, having a reducing agent, metallic nanoparticles and iron powder. There further is a writing instrument having an aqueous gel ink with variable color according to the disclosure.

The present disclosure relates to writing instruments which are charged with a water-based ink composition comprising trimethylolpropane. The present disclosure also relates to a solid ink composition which may be used to refill the rechargeable writing instrument. The solid ink composition itself is a concentrate of the water-based ink composition and can be diluted by the user with e.g. water to produce the aforementioned water-based ink composition. The present disclosure further relates to methods of producing the solid ink composition and the water-based ink composition as well as to various uses thereof.

The present invention concerns a washable aqueous ink composition comprising: a) at least one alkali metal salt of citrate, b) at least one cyclodextrin or derivative thereof, c) at least one dye. It also concerns a writing instrument comprising it and the use of the association of a) at least one alkali metal salt of citrate and b) at least one cyclodextrin or derivative thereof, to improve the washability and/or vividness of the shades of a washable aqueous ink composition.

The present invention concerns a washable aqueous ink composition comprising: a) at least one alkali metal salt of citrate, b) at least one cyclodextrin or derivative thereof, c) at least one dye. It also concerns a writing instrument comprising it and the use of the association of a) at least one alkali metal salt of citrate and b) at least one cyclodextrin or derivative thereof, to improve the washability and/or vividness of the shades of a washable aqueous ink composition.