Ink-jet recording medium, silica particles and silica dispersion

#The invention relates to silica dispersion to be used for ink-jet recording medium, hereinafter referred to as recording medium, a production method of the silica dispersion, ink-jet recording medium using the silica dispersion and the ink-jet recording medium produced by the production method.

#The ink-jet recording method is a method for recording an image or a character by flying fine droplets by various operation principles to adhere onto recording medium. Recently, the method has been rapidly spread since the method has merits such as that relatively high speed printing and low noise printing can be performed and multicolor printing can be easily realized. Moreover, the method has been applied to a high quality printing such as photographic image. Consequently, recording medium having high ink absorbability and that without foreign substance and clack on the surface and improved in the producing efficiency, and a producing method of such the recording medium are required.

#Many proposals have been disclosed for satisfying these requirements.

#FIG. 1 shows an example of the infrared spectral absorption curve of silica.

#The ink-jet recording medium according to the invention comprises a support and an ink accepting layer which is provided by coating a silica dispersion on the support to form a porous layer.

#In the ink-jet recording medium according to the invention, silica was used to form an ink accepting layer having pores. For forming the ink accepting layer, it is preferable to coat a coating liquid which prepared by mixing a dispersion comprising silica dispersed in an aqueous medium and a water-soluble polymer. As the water-soluble polymer, poly vinyl alcohol is preferably used. The silica is preferably dispersed in high concentration for raising the production efficiency. Lower viscosity of the dispersion is preferable from the viewpoint of easiness of handling. It is preferable that the amount of coarse particles contained in the dispersion is few since the presence of many coarse particles in the coated layer causes lowering of the quality by occurrence of cracks.

#Silica is roughly classified into silica produced by a gas phase method, hereinafter referred to as gas phase method-silica, and silica produced by a wet method, hereinafter referred to as wet method-silica, according to the production method thereof. The wet method-silica is classified into silica produced by a gelation method, hereinafter referred to as gel method-silica, and silica produced by a sedimentation method, hereinafter referred to as sedimentation method-silica.