Patents by Inventor Gunter Sextro
Gunter Sextro 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: 6124480Abstract: The process serves for the preparation of trioxane from formaldehyde in the gas phase in the presence of a tungstomolybdophosphoric acid of the composition H.sub.3 PW.sub.n Mo.sub.m O.sub.40 .multidot.xH.sub.2 O (n=4-8, m=12-n; x=0-32) as catalyst.Type: GrantFiled: June 30, 1995Date of Patent: September 26, 2000Inventors: Michael Hoffmockel, Gunter Sextro, Gerhard Emig, Frank Kern
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Patent number: 5872263Abstract: A process for separating a gaseous reaction mixture in the preparation of trioxane is described, in which a) the gaseous mixture leaving the reactor is scrubbed in countercurrent with an organic solvent whose boiling point is above 135.degree. C. in which the trioxane predominantly dissolves and which leaves the formaldehyde predominantly in the gas phase which is returned to the reactor, b) the trioxane together with residual formaldehyde is stripped from the solvent by distillation via a column, the overhead product being partially condensed in the temperature range from 62.degree. to 100.degree. C. c) some of the resulting condensate is applied to the column as reflux and some is taken off as product and d) the non-condensed portion is returned to the scrubbing step a).Type: GrantFiled: April 28, 1995Date of Patent: February 16, 1999Assignee: Hoechst AktiengesellschaftInventors: Michael Hoffmockel, Karl-Friedrich Muck, Gunter Sextro
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Patent number: 5587449Abstract: In the process for the preparation, with simultaneous end group stabilization, of polyacetal copolymers in a homogeneous phase and working up thereof, cyclic formaldehyde oligomers are copolymerized with cyclic acetals in the presence of an initiator in a polymerization reactor and immediately thereafter the initiator is deactivated by addition of basic substances, the unstable chain ends being degraded down to 0.01% to 1% in the presence of residual monomer, the product losing the majority of the residual monomer at the reactor outlet by letting down into a pelletizing device and the residual monomer which remains and the impurities dissolved in the product being removed by extraction with solvents and the product being pelletized, after drying and stabilization.Type: GrantFiled: August 31, 1995Date of Patent: December 24, 1996Assignee: Hoechst AktiengesellschaftInventors: Dietrich Fleischer, Michael Hoffmockel, Karl-Friedrich Muck, Gunter Sextro
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Patent number: 5508448Abstract: A process for the catalytic preparation of trioxane from formaldehyde in the gas phase employs a catalyst comprising vanadyl hydrogenphosphate hemihydrate which may be unactivated or activated by steam.No byproducts were obtained in the process and the space-time yield is high. Deposits in the reactor do not occur.Type: GrantFiled: December 30, 1993Date of Patent: April 16, 1996Assignee: Hoechst AktiengesellschaftInventors: Gerhard Emig, Benno Kruger, Frank Kern, Michael Hoffmockel, Karl-Friedrich Muck, Gunter Sextro
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Patent number: 5508449Abstract: In a process for the preparation of trioxane from formaldehyde in the gas phase in the presence of a catalyst, the catalyst employed is 11-molybdo-1-vanadophosphoric acid, H.sub.4 PVMo.sub.11 O.sub.40 .multidot.n H.sub.2 O (n=0-32).Advantages of this process are, inter alia, high space-time yields and the suppression of byproducts.Type: GrantFiled: January 6, 1994Date of Patent: April 16, 1996Assignee: Hoechst AktiengesellschaftInventors: Gerhard Emig, Benno Kruger, Frank Kern, Michael Hoffmockel, Karl-Friedrich Muck, Gunter Sextro
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Patent number: 5144005Abstract: Continuous process for removing unstable components from crude oxymethylene copolymer, which still contains catalysts, monomeric starting materials and unstable components, by treating the copolymer with deactivators, optionally in the presence of auxiliaries, in a pressure zone, and subsequently removing volatile components in a pressure-release zone in the presence or absence of stabilizers, in which process the crude polymer is fully melted in the absence of the deactivators and auxiliaries immediately after completion of the polymerization step, and the deactivators are subsequently incorporated, alone or together with auxiliaries, under pressure into the resultant polymer melt in at least one pressure zone.By this process, degradation is avoided and significantly better properties are obtained.Type: GrantFiled: February 4, 1988Date of Patent: September 1, 1992Assignee: Hoechst AktiengesellschaftInventors: Gunter Sextro, Karl-Friedrich Muck, Karlheinz Burg, Eberhard Fischer
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Patent number: 4504670Abstract: The invention provides a process for the continuous manufacture of trioxan, optionally together with cyclic formals, from aqueous formaldehyde solutions in a circulation reactor with evaporator, the vapor/liquid mixture leaving the evaporator is fed in below the liquid level of the reaction mixture. The process of the invention allows to attain especially high space/time yields.Type: GrantFiled: October 6, 1983Date of Patent: March 12, 1985Assignee: Hoechst AktiengesellschaftInventors: Hartmut Voigt, Karl-Friedrich Muck, Helmut Bar, Herbert Mader, Karlheinz Burg, Gunter Sextro
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Patent number: 4323502Abstract: A process for the simultaneous synthesis of trioxan and cyclic formals is provided, which comprises reacting a mixture of concentrated formaldehyde and diol and/or epoxide with acid catalysts at a temperature of from 30.degree. to 150.degree. C.Type: GrantFiled: October 4, 1979Date of Patent: April 6, 1982Assignee: Hoechst AktiengesellschaftInventors: Karl-Friedrich Muck, Gunter Sextro, Karlheinz Burg
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Patent number: 4195158Abstract: Oxymethylene polymers (POM) are obtained in a granular form, by cooling a POM solution or dispersion, whose temperature is above the sintering temperature of the POM, to a temperature slightly below the sintering temperature of the POM, and extracting from the suspension obtained only those POM particles which show a grain diameter of more than 70 .mu.m. As solvent or dispersing agent as well as precipitating and cooling agent there is used a mixture of methanol and water with a methanol content of at least 75% by weight. The POM obtained is suitable as engineering plastic material for the manufacture of shaped articles having improved mechanical properties.Type: GrantFiled: August 8, 1978Date of Patent: March 25, 1980Assignee: Hoechst AktiengesellschaftInventors: Karlheinz Burg, Alwin Heller, Hans-Dieter Sabel, Helmut Schlaf, Gunter Sextro
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Patent number: 4181685Abstract: Thermoplastic molding compositions having improved properties are composed of a mixture of from 99.999 to 90% by weight of a linear polyoxymethylene and from 0.001 to 10% by weight of a branched or cross-linked polyoxymethylene. The linear polyoxymethylenes are homopolymers of formaldehyde or of trioxane or copolymers of trioxane and at least one compound of monofunctional reaction which can be copolymerized with trioxane. The branched or cross-linked polyoxymethylenes are copolymers of trioxane and a multifunctionally reacting compound, or copolymers of trioxane, a monofunctionally reacting compound and a branched or cross-linked polyether. The molding compositions yield shaped articles having improved mechanical properties.Type: GrantFiled: April 14, 1976Date of Patent: January 1, 1980Assignee: Hoechst AktiengesellschaftInventors: Rudolf Kern, Heinz Schmidt, Karlheinz Burg, Ernst Wolters, Gunter Sextro
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Patent number: 4151346Abstract: Oxymethylene polymers are obtained in a granular form by cooling a solution or dispersion of an oxymethylene polymer, the temperature of which solution or dispersion is above the sintering temperature of the oxymethylene polymer, to a temperature just below the sintering temperature of the oxymethylene polymer. As dissolving or dispersing agent as well as precipitating and cooling agent there is used a mixture of methanol and water having a methanol content of at least 75% by weight. The oxymethylene polymer obtained is suitable as engineering plastic for preparing moulded articles.Type: GrantFiled: January 26, 1978Date of Patent: April 24, 1979Assignee: Hoechst AktiengesellschaftInventors: Gunter Sextro, Karlheinz Burg, Helmut Schlaf, Hans J. Leugering, Alwin Heller
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Patent number: 4111912Abstract: Granular oxymethylene polymers are prepared by cooling a solution or dispersion of an oxymethylene polymer, the temperature of the said solution or dispersion being above the sintering temperature of the oxymethylene polymer, to a temperature just below the said sintering temperature. As dissolving or dispersing agent there is used a mixture of methanol and water. The cooling of the said solution or dispersion is effected in two stages while using a liquid cooling agent or a cooling device. After precipitation the coarse-granular polymer is separated from the fine-granular portion. It is suitable as engineering plastic for preparing molded articles.Type: GrantFiled: May 4, 1977Date of Patent: September 5, 1978Assignee: Hoechst AktiengesellschaftInventors: Gunter Sextro, Karlheinz Burg, Helmut Schlaf, Hans-Dieter Sabel, Alwin Heller
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Patent number: 4070415Abstract: The invention provides thermoplastic molding compositions having improved properties. The compositions are composed of a mixture of from 99.999 to 99.9 wt.% of a linear polyoxymethylene and from 0.001 to 0.1 wt.% of a branched or cross-linked copolymer of trioxan with a multifunctionally reacting compound and optionally a monofunctionally reacting compound, or with a monofunctionally reacting compound and a branched or cross-linked polyether, or of a subsequently branched or cross-linked linear polyoxymethylene having functional groups in lateral or chain position.Type: GrantFiled: January 13, 1972Date of Patent: January 24, 1978Assignee: Hoechst AktiengesellschaftInventors: Gunter Sextro, Karlheinz Burg, Rudolf Kern, Heinz Schmidt, Ernst Wolters
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Patent number: 4046738Abstract: Oxymethylene polymers (POM) are obtained in granular form by cooling a POM solution or dispersion having a temperature above the sintering temperature of the POM in two stages to a temperature just below the said sintering temperature. The solvent or dispersion agent used is a mixture of methanol and water and the cooling agent is a methanol/water mixture which may contain POM suspended therein. The granular POM obtained is suitable as technical material for making shaped articles.Type: GrantFiled: November 5, 1975Date of Patent: September 6, 1977Assignee: Hoechst AktiengesellschaftInventors: Gunter Sextro, Karlheinz Burg, Hans Joachim Leugering, Helmut Schlaf, Alwin Heller
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Patent number: 4045415Abstract: Copolymers of trioxane with cyclic acetals may be prepared by copolymerization of the monomers in solid phase. For this purpose the monomers are first mixed homogeneously in a liquid phase with a catalyst, the mixture is then solidified by cooling and finally polymerized by heating, while maintaining it in a solid phase. The liquid phase mixture is cooled to solidify it immediately after mixing and prior to development of turbidity in the liquid mixture. Cooling can be effected, for example, on a chilled rotating roll. The moulding composition, obtained after having worked up the copolymer as usual, is a suitable material for the preparation of molded semi-finished products and finished articles.Type: GrantFiled: June 18, 1975Date of Patent: August 30, 1977Assignee: Hoechst AktiengesellschaftInventors: Gunter Sextro, Karlheinz Burg, Klemens Gutweiler, Klaus Durichen
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Patent number: 4024105Abstract: Oxymethylene copolymer having heat and hydrolysis resistant terminal groups is prepared by heating the polymers present in a liquid phase, whereby a thermal degradation of the unstable terminal groups takes place. The degradation is advantageously effected in the presence of a calcium or magnesium salt of an aliphatic carboxylic acid of low molecular weight. The oxymethylene copolymers are suitable as engineering plastic for preparing semi-finished products and finished products.Type: GrantFiled: February 20, 1975Date of Patent: May 17, 1977Assignee: Hoechst AktiengesellschaftInventors: Gunter Sextro, Karlheinz Burg, Ernst Wolters
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Patent number: 3969292Abstract: Oxymethylene polymers are stabilized against the action of heat and oxygen by a stabilizer combination of an ester of a hydroxyl group containing araliphatic or aromatic carboxylic acid and an alkaline earth metal salt of an aliphatic, araliphatic or aromatic carboxylic acid. The efficiency of the stabilizer combination can be further improved by the addition of a costabilizer, especially a guanidine compound. The stabilized poly(oxymethylenes) are suitable for the manufacture of semifinished and finished articles.Type: GrantFiled: May 30, 1975Date of Patent: July 13, 1976Assignee: Hoechst AktiengesellschaftInventors: Ernst Wolters, Heinz Schmidt, Karlheinz Burg, Gunter Sextro
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Patent number: 3940365Abstract: Polyacetals can be stabilized by means of a stabilizing composition, one of its components acting concurrently as a nucleating agent. Linear oxymethylene-polymers are used as polyacetals. The stabilizing composition consists of an urea-like compound and a phenolic anti-oxidation agent. Moulding compositions based on these stabilized polyacetals are appropriate for being worked-up in the thermoplastic state to shaped articles of all kinds.Type: GrantFiled: September 26, 1974Date of Patent: February 24, 1976Assignee: Hoechst AktiengesellschaftInventors: Hans-Hermann Grossmann, Karlheinz Burg, Gunter Sextro
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Patent number: 3931102Abstract: A moulding composition based on poly(oxymethylene) containing a substituted ureido-s-triazine as nucleating and stabilizing agent is an excellent engineering plastic useful for preparing shaped articles having stable dimensions and an exact size.Type: GrantFiled: October 4, 1974Date of Patent: January 6, 1976Assignee: Hoechst AktiengesellschaftInventors: Hans-Hermann Grossmann, Karlheinz Burg, Gunter Sextro