An ink contains water, a pigment, and a polymer having a structure unit represented by the following Chemical structure 1,

##STR00001## where R.sub.1 represents an organic group having at least carbon and oxygen.

The present invention relates to a polymer emulsion that is capable of exhibiting excellent rub fastness even when formed into a coating film or even when printed on a low-liquid absorbing printing medium, and a water-based ink for ink-jet printing which is excellent in ejection stability and antibleeding properties upon the ink-jet printing. The present invention provides [1] a polymer emulsion containing a polymer and water, in which the polymer is a random copolymer or a block copolymer which contains a constitutional unit derived from (a) at least one monomer selected from the group consisting of acrylic acid and methacrylic acid and a constitutional unit derived from (b) a hydrophobic vinyl monomer, and is in the form of a carboxy group-containing polymer having an acid value of 150 to 300 mgKOH/g; and the polymer emulsion further contains a formaldehyde-releasing compound; and [2] a water-based ink for ink-jet printing containing a pigment, the aforementioned polymer, a water-soluble organic solvent and water, in which the water-soluble organic solvent contains at least one compound selected from the group consisting of a polyhydric alcohol and a polyhydric alcohol alkyl ether, and a total content of the polyhydric alcohol and the polyhydric alcohol alkyl ether in the ink is not less than 18% by mass; and the water-based ink further contains a formaldehyde-releasing compound.

The present invention relates to a polymer emulsion that is capable of exhibiting excellent rub fastness even when formed into a coating film or even when printed on a low-liquid absorbing printing medium, and a water-based ink for ink-jet printing which is excellent in ejection stability and antibleeding properties upon the ink-jet printing. The present invention provides [1] a polymer emulsion containing a polymer and water, in which the polymer is a random copolymer or a block copolymer which contains a constitutional unit derived from (a) at least one monomer selected from the group consisting of acrylic acid and methacrylic acid and a constitutional unit derived from (b) a hydrophobic vinyl monomer, and is in the form of a carboxy group-containing polymer having an acid value of 150 to 300 mgKOH/g; and the polymer emulsion further contains a formaldehyde-releasing compound; and [2] a water-based ink for ink-jet printing containing a pigment, the aforementioned polymer, a water-soluble organic solvent and water, in which the water-soluble organic solvent contains at least one compound selected from the group consisting of a polyhydric alcohol and a polyhydric alcohol alkyl ether, and a total content of the polyhydric alcohol and the polyhydric alcohol alkyl ether in the ink is not less than 18% by mass; and the water-based ink further contains a formaldehyde-releasing compound.

The present invention relates to a pigment water dispersion containing a pigment, a crosslinked polymer and water, in which the crosslinked polymer is prepared by crosslinking a carboxy group-containing polymer with a crosslinking agent, and has an acid value of not less than 70 mgKOH/g and not more than 300 mgKOH/g; and the pigment water dispersion further contains a formaldehyde-releasing compound. The pigment water dispersion of the present invention is excellent in storage stability even when being stored under high-temperature conditions for a long period of time.

The present invention relates to a pigment water dispersion containing a pigment, a crosslinked polymer and water, in which the crosslinked polymer is prepared by crosslinking a carboxy group-containing polymer with a crosslinking agent, and has an acid value of not less than 70 mgKOH/g and not more than 300 mgKOH/g; and the pigment water dispersion further contains a formaldehyde-releasing compound. The pigment water dispersion of the present invention is excellent in storage stability even when being stored under high-temperature conditions for a long period of time.

Provided is a binder for battery electrodes which includes a polymer including: structural units (1) derived from a (meth)acrylate monomer (A) having a hydroxyl group; structural units (2) derived from a polyfunctional (meth)acrylate monomer (B); and structural units (3) derived from a reactive surfactant (C). This binder is used to prepare electrodes, and produce batteries such as lithium ion secondary batteries. Provided are: an aqueous binder which has a low environmental impact, exhibits excellent binding properties, and, notably, does not cause oxidation degradation under an electrode environment; and an electrode and a battery which use said binder.

Provided is a binder for battery electrodes which includes a polymer including: structural units (1) derived from a (meth)acrylate monomer (A) having a hydroxyl group; structural units (2) derived from a polyfunctional (meth)acrylate monomer (B); and structural units (3) derived from a reactive surfactant (C). This binder is used to prepare electrodes, and produce batteries such as lithium ion secondary batteries. Provided are: an aqueous binder which has a low environmental impact, exhibits excellent binding properties, and, notably, does not cause oxidation degradation under an electrode environment; and an electrode and a battery which use said binder.

The present invention provides a polymerizable composition containing a specific polymerizable compound and a fluorosurfactant having a specific polyoxyalkylene skeleton and having specific molecular weight. The invention also provides an optically anisotropic body, a retardation film, an antireflective film, and a liquid crystal display device that are produced using the polymerizable composition of the present invention. The present invention is useful because, when an optically anisotropic body is produced by photo-polymerization of the polymerizable composition, three features including the leveling properties of the surface of the optically anisotropic body, offset onto the substrate, and liquid crystal alignment can be improved simultaneously.

The present invention provides a polymerizable composition containing a specific polymerizable compound and a fluorosurfactant having a specific polyoxyalkylene skeleton and having specific molecular weight. The invention also provides an optically anisotropic body, a retardation film, an antireflective film, and a liquid crystal display device that are produced using the polymerizable composition of the present invention. The present invention is useful because, when an optically anisotropic body is produced by photo-polymerization of the polymerizable composition, three features including the leveling properties of the surface of the optically anisotropic body, offset onto the substrate, and liquid crystal alignment can be improved simultaneously.

Described herein are copolymers comprising at least one first water-soluble monomeric unit, at least one second water-soluble monomeric unit, and at least one monomeric unit containing a basic residue.