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. 16, 1977
Filed:
Nov. 13, 1975
Robert Bachl, Worms, DT;
Hans Frielingsdorf, Bad Duerkheim, DT;
Wolfgang Gruber, Frankenthal, DT;
Heinz Mueller-Tamm, Ludwigshafen, DT;
Leonhard Gonsior, Ludwigshafen, DT;
BASF Aktiengesellschaft, Ludwigshafen, DT;
Abstract
This invention relates to a process for the manufacture of olefin polymers by polymerization of monoolefins with the aid of a silicic xerogel/chromium trioxide catalyst obtained by (1) synthesizing a particulate silicic xerogel, (2) doping this xerogel with chromium trioxide or a chromium compound which converts to chromium trioxide under conditions of stage (3) and (3) maintaining the resulting product at an elevated temperature in a water-free oxygen-containing stream of gas. The characteristic feature of the process of the invention is that the silicic xerogel/chromium trioxide catalyst used is one obtained by (1) synthesizing the silicic xerogel in the first stage as follows: (1.1) taking an aqueous solution of a sodium silicate, (1.2) substituting substantially all of the sodium ions contained in said solution by hydrogen ions by means of an ion exchanger, (1.3) introducing a water-soluble aluminum salt into the resulting aqueous silicic acid solution, (1.4) adjusting the pH of the solution obtained in stage (1.3) to from 0.1 to 3.5, if necessary, (1.5) adjusting the solution obtained in (1.3) or (1.4) to a pH of from 4 to 12 by means of a nitrogen-base compound, (1.6) extracting the product forming the solid phase in stage (1.5) (silicic hydrogel) by means of an alkanol and/or alkanone until the organic liquid absorbs no more water and, finally, (1.7) drying the dehydrated gel saturated with organic liquid resulting from stage (1.6) (xerogel formation). This process makes it possible to obtain polymers having a satisfactory particle size distribution and a favorable melt index.