Ink composition for ink jet recording

A fine particle of a polymer for use in an ink composition for ink jet recording, said fine particle of a polymer having a film-forming property, a carboxyl group on its surface, and a reactivity with a divalent metal salt such that, when three volumes of an aqueous emulsion, of the fine particle of the polymer, having a fine particle concentration of 0.1% by weight, is brought into contact with one volume of an aqueous divalent metal salt solution having a concentration of 1 mol/liter, the time for the transmission of light at a wavelength of 700 nm to be decreased to 50% of the initial transmission is not more than 1×104, said fine particle of the polymer comprising 1 to 10% by weight of a structure derived from an unsaturated vinyl monomer having a carboxyl group and 0.2 to 4% by weight of a crosslinkable monomer-derived structure crosslinked by a crosslinkable monomer having two or more polymerizable double bonds, wherein an aqueous emulsion obtained by dispersing the fine particle of the polymer in water and having fine particle concentration of 10% by weight has a contact angle on a teflon sheet of not less than 70°.

An ink composition comprising a colorant, a fine particle of a polymer, a water-soluble organic solvent, and water, the fine particle of the polymer having a film-forming property, a carboxyl group on its surface, and a reactivity with a divalent metal salt such that, when three volumes of an aqueous emulsion, of the fine particle of the polymer, having a fine particle concentration of 0.1% by weight is brought into contact with one volume of an aqueous divalent metal salt solution having a concentration of 1 mol/liter, the time for the transmission of light at a wavelength of 700 nn to be decreased to 50% of the initial transmission is not more than 1×104 sec, the fine particle of the polymer comprising 1 to 10% by weight of a structure derived from an unsaturated vinyl monomer having a carboxyl group and 0.2 to 4% by weight of a crosslinkable monomer-derived structure crosslinked by a crosslinkable monomer having two or more polymerizable double bonds, wherein an aqueous emulsion obtained by dispersing the fine particle of the polymer in water and having fine particle concentration of 35% by weight has a surface tension of not less than 40×10−3 N/m (20° C.).

A fine particle of a polymer for use in an ink composition for ink jet recording, said fine particle of a polymer having a film-forming property, a carboxyl group on its surface, and a reactivity with a divalent metal salt such that, when three volumes of an aqueous emulsion, of the fine particle of the polymer, having a fine particle concentration of 0.1% by weight, is brought into contact with one volume of an aqueous divalent metal salt solution having a concentration of 1 mol/liter, the time for the transmission of light at a wavelength of 700 nm to be decreased to 50% of the initial transmission is not more than 1×104, said fine particle of the polymer comprising 1 to 10% by weight of a structure derived from an unsaturated vinyl monomer having a carboxyl group and 0.2 to 4% by weight of a crosslinkable monomer-derived structure crosslinked by a crosslinkable monomer having two or more polymerizable double bonds, wherein an aqueous emulsion obtained by dispersing the fine particle of the polymer in water and having fine particle concentration of 35% by weight has a surface tension of not less than 40×10−3 N/m (20° C.).