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:
Oct. 04, 1988
Filed:
Sep. 25, 1986
Klaus Unger, Seeheim-Jugenheim, DE;
Herbert Giesche, Kl.-Winternheim, DE;
Joachim Kinkel, Guldental, DE;
Merck Patent Gesellschaft mit Beschrankter Haftung, Darmstadt, DE;
Abstract
Highly monodispersed nonporous spherical SiO.sub.2 particles are prepared having mean particle diameters between 0.05 and 10 .mu.m with a standard deviation of not more than 5% and a method for the preparation of such particles. The particles can be produced by a two step process wherein first a sol of primary particles is prepared by hydrolytic polycondensation of tetraalkoxysilanes in an aqueous/alcoholic ammoniacal medium. The SiO.sub.2 particles are then converted to the desired particle size by a continuous measured addition of tetraalkoxysilane or organotrialkoxysilane controlled by the extent of the reaction. The SiO.sub.2 particles produced by this process are particularly useful as sorption material in chromatography.