Patents by Inventor Eduard Schoenafinger
Eduard Schoenafinger 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).
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Patent number: 4275114Abstract: Chromium dioxide magnetic pigments are stabilized against loss of their magnetic properties by treating them, in aqueous and/or alcoholic suspension, with a block copolymer consisting of siloxane units and alkyleneoxy units of 2 to 4 carbon atoms, the alkyleneoxy units being bonded to the polysiloxane radical by a Si--O--C or Si--C group, in an amount of from 1 to 40% by weight based on the chromium dioxide, after which the latter is separated off and dried at from 50.degree. to 200.degree. C. The stabilized chromium dioxide magnetic pigments may be used for the manufacture of magnetic recording media exhibiting improved stability of the magnetic properties under adverse climatic conditions.Type: GrantFiled: March 10, 1977Date of Patent: June 23, 1981Assignee: BASF AktiengesellschaftInventors: Eduard Schoenafinger, Herbert Motz, Manfred Ohlinger, Paul Deigner, Werner Grau
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Patent number: 4177317Abstract: Chromium dioxide magnetic pigments can be stabilized against the loss of their magnetic properties by treating them, in alcoholic aqueous suspension, with a silane or a hydrolysis product thereof, so that when the pigment is isolated from the suspension medium the particles bear at least partially hydrolyzed silane on their surfaces, and then drying the magnetic pigment at from 50.degree. to 200.degree. C.Type: GrantFiled: May 20, 1977Date of Patent: December 4, 1979Assignee: BASF AktiengesellschaftInventors: Eduard Schoenafinger, Paul Deigner, Eberhard Koester, Manfred Ohlinger, Dieter Schaefer, Werner Stumpfi, Juergen Amort, Claus-Dietrich Seiler, Heinz Nestler, Otto Ambros
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Patent number: 4109046Abstract: Flexible multi-layer magnetic recording media comprising a non-magnetic flexible base and, applied thereto, two superposed magnetizable layers which contain a homogeneous mixture of acicular magnetic chromium dioxide in an organic binder.According to the invention, the magnetizable layer adjacent to the base contains a chromium dioxide having a specific surface area, measured by the BET method, of from 15 to 25 m.sup.2 /g, while the outer magnetic layer contains a chromium dioxide having a specific surface area, measured by the BET method, of from 26 to 35 m.sup.2 /g.Such magnetic recording media are distinguished by uniformly high sensitivity over the entire audible frequency range even if close manufacturing tolerances are not maintained.Type: GrantFiled: December 3, 1976Date of Patent: August 22, 1978Assignee: BASF AktiengesellschaftInventors: Fritz Hammon, Manfred Ohlinger, Horst Grosselfinger, Heinz Stritzinger, Job-Werner Hartmann, Eduard Schoenafinger, Walter Schneider
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Patent number: 4073977Abstract: A method of stabilizing pyrophoric metal powders by treating the metal powders with alkylene oxides to form a polymer coating on the metal particles.Type: GrantFiled: June 1, 1976Date of Patent: February 14, 1978Assignee: BASF AktiengesellschaftInventors: Eberhard Koester, Gerd Wunsch, Eduard Schoenafinger, Hans H. Schneehage
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Patent number: 4071610Abstract: A process for the manufacture of acicular gamma-iron(III) oxide, in which the non-magnetic, acicular iron(III) oxide is treated with a solution of a compound of the formula I ##STR1## where R.sup.1 and R.sup.2 are ##STR2## or O--R.sup.5, R.sup.3 is H, OH, ##STR3## or O--R.sup.5, R.sup.4 is alkyl or cycloalkyl of 1 to 16 carbon atoms and the R.sup.4 's may be identical or different, and R.sup.5 is alkyl, cycloalkyl or aralkyl of 3 to 18 carbon atoms, and is then converted to gamma-iron(III) oxide by reduction to magnetite, followed by oxidation.The gamma-iron(III) oxide obtained is distinguished by a high coercive force and improved magnetic orientation when used as a magnetic pigment for the manufacture of magnetic recording media.Type: GrantFiled: April 19, 1976Date of Patent: January 31, 1978Assignee: BASF AktiengesellschaftInventors: Eberhard Koester, Gerd Wunsch, Eduard Schoenafinger, Hans Henning Schneehage
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Patent number: 4064292Abstract: The invention relates to the manufacture of acicular cobalt-modified .gamma.-iron(III) oxide by coating an acicular .alpha.-iron(III) oxide or its hydrate with an inorganic protective coating, subsequent reduction to magnetite at 350.degree. to 650.degree. C, application of the cobalt compound to this magnetite or to the .gamma.-iron(III) oxide obtained therefrom by oxidation, and subsequent heat treatment at 80.degree. to 300.degree. C, if necessary with simultaneous oxidation of the magnetite to the corresponding .gamma.-iron(III) oxide. This iron oxide has high coercivity and can be used as the magnetic component in magnetic recording media for recording high frequencies without having the disadvantage of thermal and mechanical instability.Type: GrantFiled: February 10, 1976Date of Patent: December 20, 1977Assignee: Badische Anilin- & Soda-Fabrik, AktiengesellschaftInventors: Eduard Schoenafinger, Matthias Schwarzmann, Eberhard Koester
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Patent number: 4061725Abstract: Acicular gamma-iron(III) oxide is manufactured by reacting an iron(II) salt solution with an aqueous solution of an alkali metal hydroxide and oxidizing the resulting suspension of iron(II) hydroxide in three stages. In a first stage, at most from 0.1 to 4% by weight of the amount of iron(II) hydroxide originally present is oxidized in the course of from 0.1 to 4 hours, in a second stage from 10 to 25% by weight of the said original amount are oxidized in the course of from 1.5 to 6 hours and in a third stage the remaining amount is oxidized. After the oxidation, the goethite formed is reduced to magnetite and the latter is then oxidized to acicular gamma-iron(III) oxide.Type: GrantFiled: October 15, 1976Date of Patent: December 6, 1977Assignee: BASF AktiengesellschaftInventors: Manfred Ohlinger, Eduard Schoenafinger, Walter Schneider, Heinz Stritzinger, Guenter Vaeth
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Patent number: 4061727Abstract: Acicular .gamma.-iron(III) oxide is manufactured by reacting an iron(II) salt solution with aqueous solutions of alkali metal hydroxides and oxidizing the resulting suspension of iron(II) hyroxides in 3 stages. In the first stage not more than 8 percent by weight of the iron(II) hydroxide originally present is oxidized over a period of 0.5 to 4 hours, in the second stage from 25 to 55 percent by weight over a period of 1.5 to 6 hours and the remainder thereof in a third stage. Following this oxidation, the goethite formed is reduced to magnetite, which is then oxidized to acicular .gamma.-iron(III) oxide.Type: GrantFiled: October 15, 1976Date of Patent: December 6, 1977Assignee: BASF AktiengesellschaftInventors: Guenter Vaeth, Manfred Ohlinger, Heinz Stritzinger, Eduard Schoenafinger, Eugen Wettstein, Wolfgang Guth
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Patent number: 4061726Abstract: Goethite is obtained by reacting an aqueous solution of an iron (II) salt with an aqueous solution of an alkali metal hydroxide and oxidizing the resulting iron(II) hydroxide. The oxidation is carried out in three stages. In the first stage, from 4 to 15% by weight are oxidized in the course of from 0.4 to 5 hours, in the second stage from 60 to 85% by weight are oxidized in the course of from 1.5 to 6 hours and in a third stage the remaining amount of iron is oxidized.Type: GrantFiled: October 15, 1976Date of Patent: December 6, 1977Assignee: BASF AktiengesellschaftInventors: Manfred Ohlinger, Eduard Schoenafinger, Guenter Vaeth, Heinz Stritzinger, Eberhard Koester, Hans Henning Schneehage, Werner Steck
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Patent number: 4059716Abstract: A process for the manufacture of acicular gamma-iron(III) oxide which, because of its improved dispersibility in organic binders, is suitable for the manufacture of magnetic recording media exhibiting a particularly high orientation ratio. For this purpose, the non-magnetic acicular .alpha.-iron(III) oxide or goethite pigment is treated with from 0.5 to 10% by weight, based on the pigment, of a compound of the formula I: ##STR1## where R.sup.1, R.sup.2 and R.sup.3 are hydrogen, alkyl of 1 to 24 carbon atoms or alkenyl of 1 to 24 carbon atoms and (RX).sup.- is selected from the group consisting of an aliphatic carboxylic acid of 1 to 18 carbon atoms, an aromatic carboxylic acid of 1 to 18 carbon atoms, a sulfonic acid and an ester of phosphoric acid and is then further processed by conventional methods to give gamma-iron(III) oxide.Type: GrantFiled: June 12, 1975Date of Patent: November 22, 1977Assignee: BASF AktiengesellschaftInventors: Helmut Kopke, Manfred Ohlinger, Werner Grau, Eduard Schoenafinger, Hans Henning Schneehage
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Patent number: 4052326Abstract: A process for the manufacture of acicular .gamma.-iron(III) oxide of improved crystallinity and high coercive force by heating goethite or acicular alpha-iron(III) oxide particles at temperatures of from 500.degree. to 800.degree. C, reduction of the resulting product at temperatures of from 280.degree. to 600.degree. C and subsequent oxidation of the magnetite to .gamma.-iron(III) oxide of improved crystallinity and high coercive force.Type: GrantFiled: August 30, 1976Date of Patent: October 4, 1977Assignee: BASF AktiengesellschaftInventors: Eduard Schoenafinger, Bernd Leutner
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Patent number: 4050962Abstract: A process for the manufacture of acicular ferromagnetic metal pigments containing iron, having a reduced field strength distribution and a steeper residual magnetization curve, by applying equivalent amounts of an alkaline earth metal cation and of a monobasic, dibasic or tribasic aliphatic carboxylic acid of up to 6 carbon atoms onto appropriate acicular iron oxides and then reducing the treated oxides.Type: GrantFiled: July 14, 1975Date of Patent: September 27, 1977Assignee: BASF AktiengesellschaftInventors: Eberhard Koester, Gerd Wunsch, Eduard Schoenafinger, Henning Schneehage
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Patent number: 4018882Abstract: A process for the manufacture of acicular magnetic gamma-iron(III) oxide by reducing acicular alpha-iron(III) oxide to magnetite and then oxidizing it to gamma-iron(III) oxide, wherein the alpha-iron(III) oxide is treated with a water-soluble alkaline earth metal compound and an alkylphenol with one to three alkyl radicals, each of 4 to 24 carbon atoms, on the benzene nucleus. Gamma-iron(III) oxides manufactured in this way show better magnetic orientability in the binder-containing dispersion, and a higher coercive force than prior art magnetic pigments.Type: GrantFiled: September 25, 1975Date of Patent: April 19, 1977Assignee: BASF AktiengesellschaftInventors: Eberhard Koester, Gerd Wunsch, Eduard Schoenafinger, Hans Henning Schneehage, Helmut Jakusch