A radiation-curable ink jet composition comprises a polymerizable compound component including a monofunctional monomer component and a multifunctional monomer component. The content of the monofunctional monomer component is 87 mass % or more based on the total amount of the polymerizable compound component, the monofunctional monomer component includes a monofunctional acrylate containing a polycyclic hydrocarbon group, and the weighted average of the glass transition temperatures of homopolymers of the respective polymerizable compounds is 42 C. or more when the mass ratios of the contents of the respective polymerizable compounds are weighted.

A radiation-curable ink jet composition comprises a polymerizable compound component including a monofunctional monomer component and a multifunctional monomer component. The content of the monofunctional monomer component is 87 mass % or more based on the polymerizable compound. The monofunctional monomer component includes a nitrogen-containing monofunctional monomer component, and the content of the nitrogen-containing monofunctional monomer component is 14 mass % or less based on total amount of the radiation-curable ink jet composition. The weighted average of the glass transition temperatures of homopolymers of the respective polymerizable compounds is 42 C. or more when the mass ratios of the contents of the respective polymerizable compounds are weighted.

A radiation-curable ink jet composition comprises a polymerizable compound component including a monofunctional monomer component and a multifunctional monomer component. The content of the monofunctional monomer component is 87 mass % or more based on the polymerizable compound. The monofunctional monomer component includes a nitrogen-containing monofunctional monomer component, and the content of the nitrogen-containing monofunctional monomer component is 14 mass % or less based on total amount of the radiation-curable ink jet composition. The weighted average of the glass transition temperatures of homopolymers of the respective polymerizable compounds is 42 C. or more when the mass ratios of the contents of the respective polymerizable compounds are weighted.

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.

An ultraviolet curable composition and a waveguide manufactured from the same are disclosed herein. In an embodiment, an ultraviolet curable composition for light shielding of a waveguide, comprises a colorant, an acrylate monomer, a urethane acrylate oligomer, an organosilane and a photopolymerization initiator, wherein adhesion between the cured composition and a glass substrate is 5B or greater by a ASTM D3359 standard and/or is 1,500 mN or greater by a microscratch test (MST).

An ultraviolet curable composition and a waveguide manufactured from the same are disclosed herein. In an embodiment, an ultraviolet curable composition for light shielding of a waveguide, comprises a colorant, an acrylate monomer, a urethane acrylate oligomer, an organosilane and a photopolymerization initiator, wherein adhesion between the cured composition and a glass substrate is 5B or greater by a ASTM D3359 standard and/or is 1,500 mN or greater by a microscratch test (MST).

An aqueous ink jet ink composition contains a pigment, propylene glycol, and water, in which the aqueous ink jet ink composition has the viscosity of 3.0 mm.sup.2/s or more and 10.0 mm.sup.2/s or less at 20 C., the aqueous ink jet ink composition has the pH of 7 or more, the content of the pigment is 5.5% by mass or more and 9% by mass or less based on the total amount of the aqueous ink jet ink composition, and the content of the propylene glycol is 8 parts by mass or more and 100 parts by mass or less based on 100 parts by mass of the pigment.

An aqueous ink jet ink composition contains a pigment, propylene glycol, and water, in which the aqueous ink jet ink composition has the viscosity of 3.0 mm.sup.2/s or more and 10.0 mm.sup.2/s or less at 20 C., the aqueous ink jet ink composition has the pH of 7 or more, the content of the pigment is 5.5% by mass or more and 9% by mass or less based on the total amount of the aqueous ink jet ink composition, and the content of the propylene glycol is 8 parts by mass or more and 100 parts by mass or less based on 100 parts by mass of the pigment.

An object is to improve the dispersion stability and discharge stability, while also improving the image quality and various resistance properties of printed matters even when the cohesion promoter contained in the primer ink is small in quantity. As a means to achieve the object, an ink set is provided that comprises: an aqueous inkjet ink composition containing (a) a pigment, (b) a water-soluble organic solvent, (c) water, and (d) a resin emulsion, wherein the pigment (a) has a crosslinked resin layer on its surface; and a primer ink composition containing a cohesion promoter that promotes cohesion of the aforementioned ink composition.