Patents by Inventor Gunter Buxbaum
Gunter Buxbaum 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: 4990189Abstract: Pigments for printing inks and magnetic toners are iron oxide pigments with a rhombic dodecahedral form and an average particle diameter of from 0.05 to 3.0 .mu.m with a standard deviation of the particle size distribution of .+-.30%.Type: GrantFiled: June 8, 1989Date of Patent: February 5, 1991Assignee: Bayer AktiengesellschaftInventors: Jurgen Wiese, Axel Westerhaus, Jurgen Scharschmidt, Gunter Buxbaum
-
Patent number: 4966641Abstract: Iron oxide black pigment with improved color intensity is produced by subjecting finely divided pigment obtained from reaction of metallic iron with aromatic nitro compounds to a heat treatment of 200.degree. to 800.degree. C. under a non-oxidizing atmosphere for a time of 2 minutes to 5 hours.Type: GrantFiled: December 7, 1988Date of Patent: October 30, 1990Assignee: Bayer AktiengesellschaftInventors: Axel Westerhaus, Karl-Werner Ganter, Gunter Buxbaum
-
Patent number: 4773938Abstract: Finely divided magnetic particles of hexaferrite pigments with a W-structure having the compositionE.sub.x M.sub.m (I) M.sub.n (II) Fe.sub.18 -(m+n)O.sub.27-y D.sub.ywhereinE is at least one element from the group comprising alkaline earth metals, alkali metals, lanthanides or lead,M(I) and M(II) are independently at least element from the group comprising metals or semi-metals andD is at least one element from the group of halogens and chalcogens and0.8.ltoreq.x.ltoreq.1.2,1.0.ltoreq.m.ltoreq.3.0,0.ltoreq.n.ltoreq.8.0,0.ltoreq.y.ltoreq.5.Type: GrantFiled: October 14, 1986Date of Patent: September 27, 1988Assignee: Bayer AktiengesellschaftInventors: Gunter Buxbaum, Ulrich Meisen, Florian Haberey
-
Patent number: 4753680Abstract: A bright, color-pure iron oxide red pigment is produced by an improved process by precipitation of iron(II) salts in aqueous solution with an alkaline precipitating agent, oxidation at temperatures of from 20.degree. C. to 100.degree. C. and annealing of the resulting precipitation products under air to form iron oxide red pigments, wherein the improvement comprises before adding the alkaline precipitating agent, the iron(III) content of the aqueous solution is adjusted to 1 to 15 mol %, based on the total iron content of the iron salt solution.Type: GrantFiled: December 26, 1985Date of Patent: June 28, 1988Assignee: Bayer AktiengesellschaftInventors: Wilfried Burow, Jurgen Wiese, Gunter Buxbaum
-
Patent number: 4689086Abstract: Sensitive magnetic pigment particles enclosed in about 0.1 to 5% by weight of a polymeric material thereby preserving the pigment magnetic properties. Advantageously, the polymer, which serves as a packing, is at least one member selected from the group consisting of polycarbonates, polyacrylates, polymethacrylates, polyesters, polyethers, polyurethanes, polyvinyl compounds, polyvinylidene compounds and cellulose compounds. These are compatible with the matrices used to make magnetic tapes.Type: GrantFiled: October 24, 1985Date of Patent: August 25, 1987Assignee: Bayer AktiengesellschaftInventors: Rolf Naumann, Jakob Rademachers, Gunter Buxbaum, Fritz Rodi, Karl Waid
-
Patent number: 4686142Abstract: In improved cobalt coated magnetic iron oxide having increased coercive field strength and highly efficient for use in magnetic recording devices and processes is produced by subjecting uncoated magnetic iron oxide particles to an acid treatment and then epitaxially coating the treated particles with cobalt.Type: GrantFiled: September 20, 1984Date of Patent: August 11, 1987Assignee: Bayer AktiengesellschaftInventors: Peter Kiemle, Jurgen Wiese, Gunter Buxbaum
-
Patent number: 4631090Abstract: A magnetic pigment consisting essentially of iron, having an X-ray crystallite size with the 110 reflex of from 14 to 22 nm, a coercive force from 55 to 88 kA/m and a switching field distribution of the oriented pigment particles of less than 0.55 is produced by precipitating an iron (II)-salt with a super-stoichiometric quantity of an aqueous alkali metal carbonate solution and oxidizing it to produce .alpha.-FeOOH, .gamma.-Fe.sub.2 O.sub.3, Fe.sub.3 O.sub.4 or betholoid iron oxides, subsequently reducing it to the metal, and providing the iron oxides or oxide hydroxides with an inorganic protection from sintering at the latest during reduction.Type: GrantFiled: May 31, 1985Date of Patent: December 23, 1986Assignee: Bayer AktiengesellschaftInventors: Rolf Naumann, Lutz Leitner, Jakob Rademachers, Gunter Buxbaum
-
Patent number: 4470844Abstract: Spherical agglomerates of surface-stabilized primary particles substantially consisting of iron, having a BET surface of about 5 to 50 m.sup.2 /g, measured on the agglomerate, in non-pyrophoric form and having a bulk density of about 0.5 to 2.0 kg/l and an agglomerate diameter of about 0.5 to 10 mm are produced by(a) reducing in dry phase particles consisting essentially of iron oxide,(b) intensively dispersing the particles in liquid phase,(c) coating the particles with an inorganic and/or organic coating optionally containing corrosion inhibitors,(d) separating the particles from the liquid phase by evaporating the volatile components with a continuously rotating and simultaneously tumbling movement, and(e) subjecting the resulting granulates to a thermal treatment. The particles are especially useful for the production of magnetic recording media.Type: GrantFiled: November 25, 1981Date of Patent: September 11, 1984Assignee: Bayer AktiengesellschaftInventors: Jakob Rademachers, Rolf Naumann, Hans-Peter Biermann, Gunter Buxbaum, Wolfgang Rambold
-
Patent number: 4400432Abstract: In the preparation of highly orientatable needle-shaped ferrimagnetic iron oxide particles by the reduction and reoxidation of needle-shaped particles of hydrated oxide of iron which have been surface treated against sintering the improvement which comprises effecting the surface treatment by applying to the particles of hydrated oxide of iron one layer of oxygen-containing anions and a further layer of polyvalent cations, each layer weighing about 0.02 to 2% by weight of the particle. Advantageously, the polyvalent cation-containing layer is applied between two oxygen-containing anion layers, the oxygen-containing anions used are selected from the group consisting of silicate, phosphate, borate, vanadate, molybdate and tungstate, the polyvalent cations used are selected from the group consisting of aluminum, chromium, manganese, iron and gallium, each layer weighs about 0.Type: GrantFiled: September 24, 1981Date of Patent: August 23, 1983Assignee: Bayer AktiengesellschaftInventors: Gunter Buxbaum, Ingo Pflugmacher, Franz Hund, Volker Hahnkamm, Peter Woditsch
-
Patent number: 4369265Abstract: Readily dispersible finely divided solids such as pigments, coated with an organo-silicone polymer of the formula ##EQU1## wherein R.sup.I, R.sup.II, R.sup.III each independently is an optionally halogenated alkyl, alkenyl or aryl radical having from 1 to 10 carbon atoms;R.sup.IV is an alkyl or alkenyl radical having from 9 to 24 carbon atom;R.sup.V is an alkyl or alkenyl radical having from 1 to 8 carbon atoms;the sum of a+b+c is from 1 to about 1.95;d is a number from about 0.2 to 2;e and f each independently is a number from 0 to 1;the sum of d+e+f is from about 0.2 to 2; andthe sum of a+b+c+d+e+f is up to 3.Type: GrantFiled: June 18, 1980Date of Patent: January 18, 1983Assignee: Bayer AktiengesellschaftInventors: Gunter Buxbaum, Ottfried Schlak, Franz Hund, Lutz Leitner
-
Patent number: 4323596Abstract: In the preparation of highly orientatable needle-shaped ferrimagnetic iron oxide particles by the reduction and reoxidation of needle-shaped particles of hydrated oxide of iron which have been surface treated against sintering the improvement which comprises effecting the surface treatment by applying to the particles of hydrated oxide of iron one layer of oxygen-containing anions and a further layer of polyvalent cations, each layer weighing about 0.02 to 2% by weight of the particle. Advantageously, the polyvalent cation-containing layer is applied between two oxygen-containing anion layers, the oxygen-containing anions used are selected from the group consisting of silicate, phosphate, borate, vanadate, molybdate and tungstate, the polyvalent cations used are selected from the group consisting of aluminum, chromium, manganese, iron and gallium, each layer weighs about 0.Type: GrantFiled: March 19, 1979Date of Patent: April 6, 1982Assignee: Bayer AktiengesellschaftInventors: Gunter Buxbaum, Ingo Pflugmacher, Franz Hund, Volker Hahnkamm, Peter Woditsch
-
Patent number: 4297395Abstract: A cobalt-doped, acicular ferrimagnetic iron oxide having an FeO content of about 16 to 24%, by weight, and a cobalt content of about 0.7 to 2.4%, by weight, the coercive force amounting to at least about 425 Oe+175 Oe/%, by weight, of Co is produced by precipitating and oxidizing a cobalt-containing aqueous iron (ii) salt solution, reducing the precipitate to Fe.sub.3 O.sub.4, partially reoxidizing to adjust the FeO content and heat treating under inert conditions at a temperature from about 600.degree. to 800.degree. C.Type: GrantFiled: January 10, 1980Date of Patent: October 27, 1981Assignee: Bayer AktiengesellschaftInventors: Gunter Buxbaum, Heinrich-Christian Schopper, Lutz Leitner, Volker Hahnkamm
-
Patent number: 4290799Abstract: A metal powder, suitable for magnetic recording, consisting essentially of iron, the individual particles being acicular and containing on average no more then 5 pores and consisting on average of no more than 2 metal cores is produced by precipitating and oxidizing an aqueous iron-(II)-salt solution to produce finely divided acicular iron-(III)-oxide-hydroxide, stabilizing it as by treatment with cadmium, lead, calcium, magnesium, zinc, aluminum, chromium, tungsten, a phosphorus oxide and/or a boron oxide, converting it into ferromagnetic iron oxide of low pore content, and reducing it to metallic iron with a gaseous reducing agent at about 300.degree. to 600.degree. C.Type: GrantFiled: February 25, 1980Date of Patent: September 22, 1981Assignee: Bayer AktiengesellschaftInventors: Gerhard Schroeder, Gunter Buxbaum, Franz Hund, Heinrich-Christian Schopper, Rolf Naumann
-
Patent number: 4264462Abstract: A finely divided magnetite pigment such as is used in magnetic tapes is stabilized against oxidation by contact with a heterocyclic nitrogen compound such as morpholine, triazole, piperazine or substitution products thereof. The heterocyclic compound can be applied as a solution or in vapor form.Type: GrantFiled: September 21, 1978Date of Patent: April 28, 1981Assignee: Bayer AktiengesellschaftInventors: Gunter Buxbaum, Bernd Stephan, Franz Hund, Gerhard Schroeder
-
Patent number: 4140539Abstract: An acicular to prismatic ferrimagnetic iron oxide pigment with a porosity of less than about 10% by volume, and optionally containing up to about 15% by weight of other metal oxides such as Zn or especially Co, are produced by heating a suspension of iron(III)oxide hydroxide in an autoclave to a temperature above about 100.degree. C in the presence of at least one mono-, di- or tri-saccharide, at least one alkali metal or alkaline earth metal hydroxide or carbonate and excess water, and washing, filtering and drying the resulting pigments.Type: GrantFiled: July 18, 1977Date of Patent: February 20, 1979Assignee: Bayer AktiengesellschaftInventors: Franz Hund, Gunter Buxbaum, Lutz Leitner, Ingo Pflugmacher
-
Patent number: 4112063Abstract: In the production of an FeOOH seed suspension, comprising contacting an iron(II) salt solution with a basic precipitant to form a basic iron(II) salt or hydroxide suspension, oxidizing the salt or hydroxide, the precipitation and oxidation steps being carried out locally separate from one another and recovering a suspension of FeOOH, the improvement which comprises(a) effecting the precipitation by mixing an about 1 to 20% by weight iron(II) salt solution with sufficient basic precipitant to precipitate about 25 to 95 atom % of the iron(II),(b) at another location oxidizing 10 to 50% of the iron(II) precipitated in (a) over a period of from about 0.5 to 5 hours at a temperature in the range from about 20.degree. C to 65.degree. C,(c) at another location oxidizing the suspension obtained in (b) with intensive mixing over a period of from about 0.Type: GrantFiled: December 3, 1976Date of Patent: September 5, 1978Assignee: Bayer AktiengesellschaftInventors: Gunter Buxbaum, Franz Hund
-
Patent number: 4014710Abstract: An acicular, magnetic iron oxide pigment containing about 0.05 to 5% by weight of an organo silicon compound is produced by treating iron oxide hydroxide seeds either dry or in suspension with an organo silicon compound. Preferred organo silicon compounds comprise polymethylphenylsiloxane, polydimethylsiloxane and polydiphenylsiloxane. Trivalent metal ions may subsequently be deposited. The resulting pigments show only minimal losses of coercive force during processing into magnetic tapes.Type: GrantFiled: July 18, 1974Date of Patent: March 29, 1977Assignee: Bayer AktiengesellschaftInventors: Peter Woditsch, Franz Hund, Gunter Buxbaum, Volker Hahnkamm, Ingo Pflugmacher
-
Patent number: 3931025Abstract: An acicular, magnetic iron oxide pigment containing about 0.1 to 2 percent by weight of zinc and phosphate ions is produced by growing seeds and subsequently reducing and optionally reoxidizing acicular FeOOH. Said seeds were formed by precipitation from an iron (II) salt solution in the presence of about 0.1 to 4 percent by weight of zinc ions and about 0.1 to 2 percent by weight of phosphate ions based on the formed seeds.Type: GrantFiled: August 29, 1974Date of Patent: January 6, 1976Assignee: Bayer AktiengesellschaftInventors: Peter Woditsch, Gunter Buxbaum, Franz Hund, Volker Hahnkamm