Patents by Inventor Stephan Astegger

Stephan Astegger has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Patent number: 5847129
    Abstract: The invention is concerned with a process for the destruction of N-nitrosomorpholine in an aqueous solution containing N-nitrosomorpholine and a peroxidic oxidant, characterized in that said aqueous solution is exposed to ultraviolet radiation having a wavelength of substantially 254 nm.
    Type: Grant
    Filed: April 17, 1997
    Date of Patent: December 8, 1998
    Assignee: Lenzing Aktiengesellschaft
    Inventors: Peter Harfmann, Stephan Astegger
  • Patent number: 5409532
    Abstract: Amine-oxides of the general formula: ##STR1## wherein R.sub.1 and R.sub.2 are alkyl groups with 1 to 4 C-atoms, R.sub.3 is hydrogen, a hydroxyl group or an alkoxy group with 1 to 4 C-atoms and m and n are whole numbers which fulfil the conditions 1.ltoreq.m.ltoreq.8 and 0.ltoreq.n.ltoreq.4 respectively, with the proviso that n is not 0 if R.sub.3 is a hydroxyl group or an alkoxy group, can be used with advantage for the preparation of mouldable or spinnable cellulose solutions which have a reduced tendency to crystallise.
    Type: Grant
    Filed: January 21, 1993
    Date of Patent: April 25, 1995
    Assignee: Lenzing Aktiengesellschaft
    Inventors: Stephan Astegger, Dieter Eichinger, Heinz Falk, Gunter Teubl
  • Patent number: 5216144
    Abstract: Shaped cellulosic bodies and especially cellulosic fibers or filaments are produced by precipitating cellulose from a solution containing cellulose and NMMO. To allow elevated concentrations of NMMO in the precipitating bath without detriment to the properties of the fibers or filaments produced, the temperature of the precipitating bath is held at most at 0.degree. C.
    Type: Grant
    Filed: December 6, 1991
    Date of Patent: June 1, 1993
    Assignee: Lenzing Aktiengesellschaft
    Inventors: Dieter Eichinger, Raimund Jurkovic, Stephan Astegger, Heinrich Firgo, Peter Hinterholzer, Karin Weinzierl, Stefan Zikeli
  • Patent number: 5189152
    Abstract: A solution of cellulose in water and N-methylmorpholine-N-oxide (NMMO) containing 2 to 44% by weight cellulose is stabilized at 0.01 to 1%, preferably 0.1% H.sub.2 O.sub.2 and 0.01 to 2%, preferably 0.1% of an H.sub.2 O.sub.2 stabilizer, preferably oxalic acid or a salt thereof during formation of the solution and during heating to prevent discoloration of the cellulose and reduce the composition of NMMO.
    Type: Grant
    Filed: July 16, 1991
    Date of Patent: February 23, 1993
    Assignee: Lenzing Aktiengesellschaft
    Inventors: Peter Hinterholzer, Stefan Zikeli, Heinrich Firgo, Bernd Wolschner, Dieter Eichinger, Johann Manner, Stephan Astegger, Karin Weinzierl
  • Patent number: 5118423
    Abstract: For the removal of water from dilute aqueous solution of NMMO, N-methylmorpholine or morpholine or mixtures thereof, the solution is subjected to reverse osmosis at a pressure in excess of the osmotic pressure and probably around 40 bar and a temperature of 25.degree. C. to 75.degree. C. to form a retentate containing the amines and a permeate which is practically free from the amines. The permeate can be used as process water while the retentate can be worked up to NMMO for reuse in the cellulose solubilization process.
    Type: Grant
    Filed: March 27, 1991
    Date of Patent: June 2, 1992
    Assignee: Lenzing Aktiengesellschaft
    Inventors: Stephan Astegger, Dieter Eichinger, Heinrich Firgo, Karin Weinzierl, Bernd Wolschner, Stefan Zikeli
  • Patent number: 5053138
    Abstract: There is disclosed a process for purifying aqueous solutions of N-methyl-morpholine N-oxide (NMMO), such as spinning bath solutions incurred in the production of cellulose products, in which process the solutions to be purified are contacted with an anion exchanger and the purified solutions are separated from the anion exchanger. The process is carried out in one step and the anion exchanger, as functional groups, exclusively contains quaternary tetraalkylammonium groups of the formulae--CH.sub.2 --N.sup..sym. (CH.sub.3).sub.3 X.sup..crclbar. or --CH.sub.2 --N.sup..sym. [(CH.sub.3).sub.2 (CH.sub.2 OH)]X.sup..crclbar.wherein X.sup..crclbar. represents the anion of an inorganic or organic acid. After this, the anion exchanger is regenerated with an aqueous acidic solution.
    Type: Grant
    Filed: October 11, 1990
    Date of Patent: October 1, 1991
    Assignee: Lenzing Aktiengesellschaft
    Inventors: Dietmar Korger, Dieter Eichinger, Stephan Astegger, Karin Weinzierl, Johann Manner
  • Patent number: 5043075
    Abstract: There is disclosed a method of removing amines from aqueous solutions thereof, in particular from waste waters obtained in cellulose processing. The aqueous amine solutions are contacted with a cation exchanger whose anchor groups consist of carboxyl groups, in order to charge the cation exchanger with the amines. The charged cation exchanger is treated with an aqueous solution of a weak acid having a pK.sub.a larger than 3.0 in order to elute the amines. The eluate is processed by way of distillation, wherein a portion of the weak acid is separated from the amines and reclaimed, if desired.The method according to the invention offers a simple and cheap way of disposing amine-containing waste waters.
    Type: Grant
    Filed: May 24, 1990
    Date of Patent: August 27, 1991
    Assignee: Lenzing Aktiengesellschaft
    Inventors: Korger Dietmar, Stephan Astegger, Dieter Eichinger, Heinrich Firgo