The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Aug. 20, 1996
Filed:
Oct. 13, 1994
Nissan Chemical Industries, Ltd., Tokyo, JP;
Abstract
A stable aqueous sol of amorphous alumina containing Al.sub.2 O.sub.3 up to 15% by weight and 0.1 to 0.5 gram equivalent of an anion of acid to 1 mol of aluminum in the sol, in which the colloidal particles of amorphous alumina have a controlled thickness in a range of 20 to 100 millimicrons and a uniform length in a range of 200 to 500 millimicrons is produced by a process comprising feeding an aqueous solution of an acid into an aqueous slurry containing 1 to 7% by weight of metallic aluminum, 10 to 200 ppm by weight as SiO.sub.2 of a water-soluble silicate and 0 to 20 ppm by weight of a water-soluble sulfate as SO.sub.4 to the water in the slurry while maintaining the slurry at a temperature of 80.degree. C. to boiling point under normal pressure, said acid being in an amount of 0.1 to 0.5 gram equivalent to 1 mol of the metallic aluminum in said slurry, at a rate of 0.001 to 0.03 gram equivalent of the acid to 1,000 g of the water in the slurry per minute, and continuing heating the slurry after completion of the feeding of the acid at a temperature of 80.degree. C. to boiling point of the slurry until a sol of amorphous alumina having a uniform length of 200 to 500 millimicrons is formed.