Asahi Glass Company, Limited

Hisao Inokuma

Toshiya Matsubara

Katsumasa Nakahara

Akira Mitsui

Hachiro Hirano

Hirokazu Wakabayashi

Toshihiko Higuchi

Shinichi Suzuki

Yoshinori Kon

Hachirou Hirano

Noriko Torimoto

Masako Wakabayashi

A light diffusion plate has a substrate and a light diffusion layer formed on the substrate. The light diffusion layer is composed of at least two layers: a first light diffusion layer containing a first matrix and a first light diffusion agent having a refractive index difference &#x394;nof 0.04&#x2266;&#x394;n&#x2266;0.2 with the first matrix, and a second light diffusion layer containing a second matrix and a second light diffusion agent having a refractive index difference &#x394;nof 0.005&#x2266;&#x394;n&#x2266;0.01 with the second matrix. The volume fraction of the first light diffusion agent in the first light diffusion layer is less than 40%, the volume fraction of the second light diffusion agent in the second light diffusion layer is at least 40% and the total thickness of the light diffusion layers is from 5 to 200 &#x3bc;m after curing.

Light diffusion plate and its production process

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.

Recording medium excellent in ink absorptivity and process for its production, and process for producing silica-alumina composite sol

It is an object of the present invention to obtain a composite sol capable of forming an ink-receiving layer having a high transparency and a high property for fixing dyes. The present invention provides a sol which is a colloidal solution having aggregate particles containing silica and alumina dispersed in an aqueous medium, wherein the silica is such that the primary particles are spherical and the average particle size of the primary particles is from 2 to 200 nm, the average particle size of the aggregate particles is at least twice the average particle size of the silica primary particles and at most 1,000 nm, the &zgr;-potential of the aggregate particles is at least &plus;10 mV, and the pH of the solution is from 3 to 9. The present invention provides a method for producing a silica-alumina composite sol, which comprises gradually adding an aluminum salt of which the liquid exhibits acidity when dissolved in water, to a silica sol, and a method for producing a silica-alumina composite sol, which comprises mixing a silica sol with an alumina sol having a specific surface area of a xerogel obtainable by drying of at least 150 m /g, to form aggregate particles containing silica and alumina, followed by peptization treatment.

Silica-alumina composite sol, processes for producing the same, and recording medium

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Chiba, Japan

Hisao Inokuma