An example of a radiation curable binder dispersion for an inkjet ink includes water and a radiation curable polyurethane dispersed in the water. The radiation curable polyurethane has a weight average molecular weight that is equal to or less than 5,000, a glass transition temperature (T.sub.g) less than 25° C., and a double bond density higher than 4.0. The radiation curable polyurethane binder dispersion is formed from a non-aromatic diisocyanate; a polyol; an acrylate or methacrylate, the acrylate or methacrylate having at least two hydroxyl functional groups and having an acrylate functional group or a methacrylate functional group; a compound including i) an ionic group or ii) a group to form an ionic group; and another acrylate or methacrylate, the other acrylate or methacrylate having a hydroxyl functional group or an amino functional group.

An example of a radiation curable binder dispersion for an inkjet ink includes water and a radiation curable polyurethane dispersed in the water. The radiation curable polyurethane has a weight average molecular weight that is equal to or less than 5,000, a glass transition temperature (T.sub.g) less than 25° C., and a double bond density higher than 4.0. The radiation curable polyurethane binder dispersion is formed from a non-aromatic diisocyanate; a polyol; an acrylate or methacrylate, the acrylate or methacrylate having at least two hydroxyl functional groups and having an acrylate functional group or a methacrylate functional group; a compound including i) an ionic group or ii) a group to form an ionic group; and another acrylate or methacrylate, the other acrylate or methacrylate having a hydroxyl functional group or an amino functional group.

An ink jet recording method is a method in which a cyan ink, a magenta ink, a black ink, and a yellow ink radiation that are curable inks are ejected from ink jet heads to attach the radiation curable inks to a recording medium. The method includes, in this order, a first step of attaching the cyan ink, the magenta ink, and the black ink onto the recording medium and applying temporary curing radiation to the recording medium and a second step of attaching the yellow ink onto the recording medium and applying full curing radiation to the recording medium without applying the temporary curing radiation.

An ink jet recording method is a method in which a cyan ink, a magenta ink, a black ink, and a yellow ink radiation that are curable inks are ejected from ink jet heads to attach the radiation curable inks to a recording medium. The method includes, in this order, a first step of attaching the cyan ink, the magenta ink, and the black ink onto the recording medium and applying temporary curing radiation to the recording medium and a second step of attaching the yellow ink onto the recording medium and applying full curing radiation to the recording medium without applying the temporary curing radiation.

Provided is an ink set including a first ink and a second ink. The second ink contains a high-viscosity component having a viscosity of 500 mPa.Math.s or higher at 25 degrees C., and a low-viscosity component having a viscosity of 30 mPa.Math.s or lower at 25 degrees C. A static surface tension γ1 (mN/m) of the first ink and a static surface tension γ2 (mN/m) of the second ink satisfy General formula (1) below.

1 (mN/m)≤γ1−γ2≤5 (mN/m)  General formula (1)

A content A (% by mass) of each component contained in the first ink, a static surface tension B (mN/m) of each component contained in the first ink, a content C (% by mass) of each component contained in the second ink, and a static surface tension D (mN/m) of each component contained in the second ink satisfy General formula (2) below.

ΣA/Σ(A/B)−ΣC/Σ(C/D)≥0 (mN/m)  General formula (2)

Self-sintering conductive inks can be printed and self-sintered with a simple and low-cost process mechanized by exothermic alkali metal and water reaction, with enhanced electrical and thermal performance by liquid metal fusion. Such self-sintering conductive inks may include a gallium-alkali metal component and a water absorbing gel component. After patterning, the self-sintering inks, on reaching a designed trigger temperature (including room temperature), may metallize through a two-step process. Initially the gallium-alkali metal component activates and reacts with water released from the water absorbing gel component. Then the exothermic reaction between the water and the alkali element creates an intense and highly localized heating effect, which liquefies all metallic components in the ink and, on cooling, creates a solid metal trace or interconnect. Post cooling, the metal trace or interconnect cannot be reflowed without a significant temperature increase or other energetic input.

A method for manufacturing an electromagnetic shielding film of reduced thickness and a simplified manufacturing process includes forming a conductive ink layer by inkjet printing, on a component to be shielded, forming an insulative ink layer on the conductive ink layer by inkjet printing, and sintering the conductive ink layer and the insulative ink layer to form an electromagnetic shielding layer and an insulative layer, thereby obtaining the electromagnetic shielding film.

A method for manufacturing an electromagnetic shielding film of reduced thickness and a simplified manufacturing process includes forming a conductive ink layer by inkjet printing, on a component to be shielded, forming an insulative ink layer on the conductive ink layer by inkjet printing, and sintering the conductive ink layer and the insulative ink layer to form an electromagnetic shielding layer and an insulative layer, thereby obtaining the electromagnetic shielding film.

An ink jet printing method includes a metallic ink application step of ejecting a metallic ink composition containing a metallic pigment from an ink jet head to apply the metallic ink composition onto a printing medium, a heating step of heating the metallic ink composition applied on the printing medium with an infrared heater, and a coloring ink application step of ejecting a coloring ink composition containing a coloring material from an ink jet head to apply the coloring ink composition onto the metallic ink composition on the printing medium. Each of the metallic ink composition and the coloring ink composition is a water-based ink or a solvent-based ink.

An ink jet printing method includes a metallic ink application step of ejecting a metallic ink composition containing a metallic pigment from an ink jet head to apply the metallic ink composition onto a printing medium, a heating step of heating the metallic ink composition applied on the printing medium with an infrared heater, and a coloring ink application step of ejecting a coloring ink composition containing a coloring material from an ink jet head to apply the coloring ink composition onto the metallic ink composition on the printing medium. Each of the metallic ink composition and the coloring ink composition is a water-based ink or a solvent-based ink.