Method for applying ink and method for producing wallpaper

A method for producing a wallpaper by applying an oil-based ink to a resin composition layer of a target that comprises a base and the resin composition layer formed over a surface of the base, the method comprising:

• pre-treating a surface of the resin composition layer before the oil-based ink is applied, with at least one surface treatment for improving a wetting/spreading property of the oil-based ink;
• applying the oil-based ink to the surface of the resin composition layer that has undergone the pre-treating;
• and
• post-treating the surface of the resin composition layer after the oil-based ink is applied, with at least one surface treatment for improving a wetting/spreading property of the oil-based ink;
• wherein the applying step comprises applying the oil-based ink directly to the pre-treated surface of the resin composition layer.

A method for applying an ink, the method being intended to apply an oil-based ink to a resin composition layer of a target that comprises a base and the resin composition layer formed over a surface of the base, the method comprising:

• pre-treating the target before the oil-based ink is applied, with at least one surface treatment for improving a wetting/spreading property of the oil-based ink;
• applying the oil-based ink to the target that has undergone the pre-treating;
• and
• post-treating the target after the oil-based ink is applied, with at least one surface treatment for improving a wetting/spreading property of the oil-based ink,
• wherein a mass change rate of the oil-based ink when the oil-based ink is left to stand at 150 degrees C. for 60 minutes is 5% or lower.