Abstract: Provided is a fine powder material for forming an ink-receiving layer on a recording medium, wherein a pore radius maximum exists within a range of from 90 to 120 Å in a pore radius distribution of said fine powder material and wherein a total volume of pores having radii not exceeding 50 Å is not more than 6.0% of a volume of all pores.

Abstract: It is an object of the present invention to provide an ink jet recording sheet which has high glossiness of the recording surface and is free from the bleeding of an image with time even under high temperature and humidity. Also, the recording sheet can avoid the occurrence of cracks, is strong, possesses high ink-absorbing ability, and can form an image with high light resistance and water resistance. The ink jet recording sheet comprises a polymer which contains a quaternary ammonium base in its molecule, of which the ratio of inorganicity/organicity (I/O value) calculated based on an organic conceptual diagram is 1.0 or less and the cation density (meq/g) is 3.0 or less, and which is soluble in at least one of water and an organic solvent.

Abstract: A process for producing a silica-alumina composite sol, which comprises mixing a silica hydrogel and an aluminum salt which, when dissolved in water, gives an acidic solution.