Patents by Inventor Michel Letoffe

Michel Letoffe 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: 6521699
    Abstract: The invention concerns a silicon dispersion hardenable by cross-linking and useable particularly as putty, paint or film coating. The dispersion according to the instant invention contains hydroxylated condensable constituents and is free from hydrolyzable substituents capable of being transformed into volatile organic compounds, is free from volatile organic compounds and polyvinil alcohol, and contains an &agr;,&ohgr;-diOH polyorganosiloxane (A), an adherence promoter (B) with NH2 functions and OH functions, and, optionally, a catalyst (C), a surfactant (D), a cross-linking agent (E), fillers (F), a dispersing agent (G), a plasticizer (H), an antifungal agent (I), an antifoaming agent (J), a stabilizer (K) or a base (L). The invention is useful for putty or film coatings prepared with this dispersion.
    Type: Grant
    Filed: April 27, 2001
    Date of Patent: February 18, 2003
    Inventors: Michel Feder, Philippe Jost, Michel Letoffe, Marie-Cécile Duchamp
  • Publication number: 20010031818
    Abstract: The invention concerns a silicon dispersion hardenable by cross-linking and useable particularly as putty, paint or film coating. The dispersion according to the instant invention contains hydroxylated condensable constituents and is free from hydrolyzable substituents capable of being transformed into volatile organic compounds, is free from volatile organic compounds and polyvinil alcohol, and contains an &agr;,&ohgr;-diOH polyorganosiloxane (A), an adherence promoter (B) with NH2 functions and OH functions, and, optionally, a catalyst (C), a surfactant (D), a cross-linking agent (E), fillers (F), a dispersing agent (G), a plasticizer (H), an antifungal agent (I), an antifoaming agent (J), a stabilizer (K) or a base (L). The invention is useful for putty or film coatings prepared with this dispersion.
    Type: Application
    Filed: April 27, 2001
    Publication date: October 18, 2001
    Inventors: Michel Feder, Philippe Jost, Michel Letoffe, Marie-Cecile Duchamp
  • Patent number: 6124235
    Abstract: An accelerator system for the cold crosslinking of polymers which harden on exposure to moisture by hydrolysis/condensation, comprising: (C) x parts by weight of a catalyst for crosslinking the said polymers by polycondensation, x ranging from 0.01 to 10; (E) Y parts by weight of a solid inorganic compound containing an amount y of water in the form of water of hydration and/or water adsorbed by capillary condensation, this amount y ranging from 0.5 to 40 parts by weight, and which can represent up to 70% of the weight of the said solid inorganic compound; (F) z parts by weight of fillers, z ranging from 0 to 50; (D) 100-(x+Y+z) parts by weight of a diluent or of a solvent of the said catalyst (C), the diluent or solvent having a dynamic viscosity at 25.degree. C. of the order of 50 to 200,000 mPa.s; the respective amounts of the four constituents (C), (E), (F) and (D) being such that the system obtained exists in the form of a manipulable paste.
    Type: Grant
    Filed: July 3, 1997
    Date of Patent: September 26, 2000
    Assignee: Rhone-Poulenc Chimie
    Inventors: Michel Letoffe, Jean-Marc Pujol
  • Patent number: 5681884
    Abstract: An accelerator system for the cold crosslinking of polymers which harden on exposure to moisture by hydrolysis/condensation, comprising: (C) x parts by weight of a catalyst for crosslinking the said polymers by polycondensation, x ranging from 0.01 to 10; (E) Y parts by weight of a solid inorganic compound containing an amount y of water in the form of water of hydration and/or water adsorbed by capillary condensation, this amount y ranging from 0.5 to 40 parts by weight, and which can represent up to 70% of the weight of the said solid inorganic compound; (F) z parts by weight of fillers, z ranging from 0 to 50; (D) 100-(x+Y+z) parts by weight of a diluent or of a solvent of the said catalyst (C), the diluent or solvent having a dynamic viscosity at 25.degree. C. of the order of 50 to 200,000 mPa.s; the respective amounts of the four constituents (C), (E), (F) and (D) being such that the system obtained exists in the form of a manipulable paste.
    Type: Grant
    Filed: September 22, 1994
    Date of Patent: October 28, 1997
    Assignee: Rhone-Poulenc Chimie
    Inventors: Michel Letoffe, Jean-Marc Pujol
  • Patent number: 5079324
    Abstract: Functionalized diorganopolysiloxanes containing alkoxy endgroups, well adapted for the formulation of single-component cold-vulcanizable elastomer compositions therefrom, are prepared by reacting an .alpha., .omega.-dihydroxydiorganopolysiloxane oil with a polyalkoxysilane in the presence of a catalytically effective amount of lithium hydroxide.
    Type: Grant
    Filed: November 6, 1989
    Date of Patent: January 7, 1992
    Assignee: Rhone-Poulenc Chimie
    Inventors: Roger Cocco, Michel Letoffe, Georges Nielsen
  • Patent number: 4956436
    Abstract: Organopolysiloxane compositions curable into elastomeric state, whether in single- or two-component form, comprise an .alpha.,.omega.-dihydroxypolydiorganopolysiloxane oil, a crosslinking agent therefor, optionally, inorganic fillers and an adhesion promoter, and a catalytically effective amount of a pentacoordinated tin monochelate produced by reacting a .beta.-dicarbonyl compound with an organotin salt.
    Type: Grant
    Filed: June 27, 1988
    Date of Patent: September 11, 1990
    Assignee: Rhone-Poulenc Chimie
    Inventors: Michel Letoffe, Claude Millet, Serge Serafini
  • Patent number: 4824924
    Abstract: The diorganopolysiloxane alpha, omega-diol oils are terminally alkoxylated by reacting same with a polyalkoxysilane in the presence of an organic oxime devoid of silicon atoms. The resulting functionalized oils are well adapted for the formulation of single-component, storage-stable organopolysiloxane CVE compositions.
    Type: Grant
    Filed: April 28, 1987
    Date of Patent: April 25, 1989
    Assignee: Rhone-Poulenc Chimie
    Inventors: Michel Letoffe, Pierre-Michel Peccoux
  • Patent number: 4797462
    Abstract: Organopolysiloxanes curable into elastomeric state, well adapted as sealing materials for a variety of substrates and useful, e.g., in the automotive industry, are comprised of a polyhydroxylated polysiloxane, a polyacyloxysilane crosslinking agent, and an effective amount of at least one calcium oxide, strontium oxide and/or barium oxide cure accelerator therefor. The subject compositions are stable for at least 10 minutes at ambient temperature and crosslink on heating and/or addition of an aqueous or liquid carboxylic acid promoter thereto.
    Type: Grant
    Filed: September 11, 1987
    Date of Patent: January 10, 1989
    Assignee: Rhone-Poulenc Chimie
    Inventors: Michel Letoffe, Georges Barrandon
  • Patent number: 4769409
    Abstract: Single-component diorganopolysiloxane compositions which are storage-stable in the absence of atmospheric moisture and which crosslink into silicone elastomeric state in the presence of moisture, are comprised of an alkoxy-terminated diorganopolysiloxane, a functionalization catalyst containing a primary or secondary amine group, a tin condensation catalyst, a filler material, and an effective stabilizing amount of an alkyl or aryl isocyanate-substituted diorganopolysiloxane.
    Type: Grant
    Filed: April 28, 1987
    Date of Patent: September 6, 1988
    Assignee: Rhone-Poulenc Chimie
    Inventors: Michel Gay, Michel Letoffe, Pierre-Michel Peccoux
  • Patent number: 4762879
    Abstract: Single-component diorganopolysiloxane compositions which are storage-stable in the absence of atmospheric moisture and which crosslink into silicone elastomeric state in the presence of moisture, are comprised of an alkoxy-terminated diorganopolysiloxane, a functionalization catalyst containing a primary or secondary amine group, a tin condensation catalyst, a filler material, and an effective stabilizing amount of an isocyanurate of the formula: ##STR1## wherein W is --CH.sub.2).sub.n N.dbd.C.dbd.O and n ranges from 1 to 12.
    Type: Grant
    Filed: April 28, 1987
    Date of Patent: August 9, 1988
    Assignee: Rhone-Poulenc Chimie
    Inventors: Michel Letoffe, Pierre-Michel Peccoux
  • Patent number: 4755579
    Abstract: Organopolysiloxane compositions comprising a polyhydroxylated polysiloxane and a polyacyloxysilane, whether in single- or two-component form, rapidly cure into elastomeric state (and are thus useful, e.g., as sealing materials) in the presence of a 2-carboxycarboxamide cure autoaccelerator.
    Type: Grant
    Filed: June 16, 1987
    Date of Patent: July 5, 1988
    Assignee: Rhone-Poulenc Specialites Chimiques
    Inventor: Michel Letoffe
  • Patent number: 4748166
    Abstract: Storage stable, water-free, RTV organopolysiloxane adhesives curable in the presence of water or atmospheric moisture, and comprising a dihydroxydiorganopolysiloxane polymer, fillers, an amine fraction and a curing catalyst, are characterized by incorporation therein of a polyalkoxylated organosilane having the formula:R'.sub.x Si[(OCH.sub.2 CH.sub.2).sub.p OCH.sub.3 ].sub.4-xwherein R' is methyl, vinyl, allyl, methallyl or phenyl, and p and x are each one or two.
    Type: Grant
    Filed: May 28, 1986
    Date of Patent: May 31, 1988
    Assignee: Rhone-Poulenc Industries
    Inventors: Alain Gautier, Bernard Laisney, Michel Letoffe
  • Patent number: 4672003
    Abstract: Novel RTV organopolysiloxane compositions, advantageously two-component compositions, which are easily vulcanized into self-adhesive elastomers having excellent reversion properties, are comprised of (1) at least one alpha, omega-dihydroxydiorganopolysiloxane polymer having a viscosity of from about 500 to 1,000,000 mPa.s at 25.degree. C., the organic radicals of which being monovalent hydrocarbon radicals, (2) at least one filler material therefor, (3) at least one polyalkoxysilane or polyalkoxysiloxane cross-linking agent therefor, (4) a catalytically effective amount of at least one tin catalyst, and (5) at least one silane having the general formula: ##STR1## wherein R is an alkyl or alkoxy radical having from 1 to 4 carbon atoms, at least 2 of said radicals R being alkoxy radicals, R' is an alkyl radical having from 1 to 3 carbon atoms, and n is an integer of from 3 to 10.
    Type: Grant
    Filed: October 29, 1985
    Date of Patent: June 9, 1987
    Assignee: Rhone-Poulenc Specialites Chimiques
    Inventor: Michel Letoffe
  • Patent number: 4604444
    Abstract: Organopolysiloxane compositions readily cross-linked into elastomers, e.g., elastomeric seals, and advantageously formulated in either one- or two-component packages, are comprised of (A) a polyhydroxylated polysiloxane, (B) a polyacyloxysilane cross-linking agent and (C) a hardening accelerator therefor, said hardening accelerator being protectively microencapsulated within impermeable outer skin membranes adopted to be chemically or physically disrupted, e.g., by heat, irradiation or mechanical breaking, to permit the release of said accelerator (C) therefrom and consequent curing of the composition.
    Type: Grant
    Filed: October 19, 1984
    Date of Patent: August 5, 1986
    Assignee: Rhone-Poulenc Specialites Chimiques
    Inventors: Andre Donnadieu, Michel Letoffe
  • Patent number: 4532315
    Abstract: Organopolysiloxane compositions which rapidly harden to the elastomeric state, even at ambient temperatures, are comprised of (i) a polyhydroxylated polysiloxane, (ii) a polyacyloxysilane cross-linking agent therefor, and (iii) a hardening accelerator comprising an alkali or alkaline earth metal hydroxide. The subject compositions are useful, inter alia, for providing elastomeric seals.
    Type: Grant
    Filed: January 25, 1984
    Date of Patent: July 30, 1985
    Assignee: Rhone-Poulenc Specialites Chimiques
    Inventors: Michel Letoffe, Roger Favre, Patrice Perrin
  • Patent number: 4525565
    Abstract: Provided are single component organopolysiloxane compositions which are hardenable at ambient temperatures and contain as the cross-linking agent silanes with hydrocarbonoyloxy (acyloxy) or ketoniminoxy groups. The compositions further comprise a cross-linking catalyst which is an organic derivative of titanium, e.g., a titanium ester, polytitanoxane, alkanolamine titanate, etc., or an organic derivative of zirconium, e.g., a zirconate, polyzirconate, etc. After cross-linking, the present compositions provide organopolysiloxane elastomers exhibiting good properties.The organopolysiloxane compositions are referred to as "single component" to contrast them with the two-component organopolysiloxane compositions which are not storage stable and must therefore be handled in two separate packages, which problem is overcome by the present compositions.
    Type: Grant
    Filed: July 29, 1983
    Date of Patent: June 25, 1985
    Assignee: Rhone-Poulenc Specialites Chimiques
    Inventors: Bernard Laisney, Michel Letoffe, Patrice Perrin, Jean Ulrich
  • Patent number: 4508888
    Abstract: Organopolysiloxane compositions which rapidly harden to the elastomeric state, even at ambient temperatures, are comprised of (i) a polyhydroxylated polysiloxane, (ii) a polyacyloxysilane cross-linking agent therefor, and (iii) a hardening accelerator comprising water and an alkali or alkaline earth metal phosphate and/or polyphosphate. The subject compositions are useful, inter alia, for providing elastomeric seals.
    Type: Grant
    Filed: January 25, 1984
    Date of Patent: April 2, 1985
    Assignee: Rhone-Poulenc Specialites Chimiques
    Inventors: Michel Letoffe, Roger Favre, Patrice Perrin
  • Patent number: 4143088
    Abstract: An organosilicon composition is disclosed which is storage-stable in the absence of moisture and is rapidly curable into elastomers with self-adherent properties in the presence of water at room temperature. Such compositions are prepared by mixing:(a) at least one .alpha.,.omega.-di(hydroxy) diorganopolysiloxane polymer,(b) at least one organosilicon resin,(c) at least one alkoxylated organosilicon compound, and(d) at least one organic titanium derivative.
    Type: Grant
    Filed: March 24, 1977
    Date of Patent: March 6, 1979
    Assignee: Rhone-Poulenc Industries
    Inventors: Georges Favre, Andre Gibard, Michel Letoffe
  • Patent number: 3983265
    Abstract: Substrates, particularly electronic connections, are protected by coating the substrate with a curable organosilicon composition based on .alpha.-.omega.-dihydroxy diorganopolysiloxanes, methyl polysiloxanes, fillers, amino organosilicon cross linking agents and optionally alkyl silicates or polysilicates, which are vulcanizable at ambient temperature or above, are improved by using a methylpolysiloxane in which the ratio of the R(CH.sub.3).sub.2 SiO.sub.0.5 units (R=C.sub.1 --C.sub.3 alkyl or vinyl) to SiO.sub.2 units is 0.4:1 to 1.2:1 and which contains 0.5 - 3.5% by weight OH groups bonded to Si and by using an amino organosilicon compound which is an aminoorganosilane of the general formula (i) (R"O).sub.3.sub.-p R'.sub.p Si[(CH.sub.2).sub.n O].sub.m (CH.sub.2).sub.t NHQ in which R' represents an alkyl group with 1 to 4 carbon atoms, a vinyl group or a phenyl group, R" represents a methyl, ethyl or methoxyethyl radical, Q represents a hydrogen atom or the radical --(CH.sub.2).sub.2 NH.sub.
    Type: Grant
    Filed: May 14, 1975
    Date of Patent: September 28, 1976
    Assignee: Rhone-Poulenc S.A.
    Inventor: Michel Letoffe
  • Patent number: 3965280
    Abstract: Electrical and electronic devices are coated with an organopolysiloxane composition which consists essentially of a mixture of the following ingredients by weight:I 100 parts of a .alpha.,.omega.-dihydroxydiorganopolysiloxane polymer, of viscosity at least about 600 cPo at 25.degree.C,ii 1 to 15 parts of an organosilicon compound which is eitherA a monomer of the formula (A): R.sub.x Si[(OCH.sub.2 CH.sub.2).sub.a OR'].sub.4.sub.-x', orB a polymer resulting from the partial hydrolysis of at least one monomer of formula Si(OR').sub.4 ;iii 0.2 to 6 parts of an organic derivative of titanium, which is either:A a monomer of the formula (B): Ti[OCH.sub.2 CH.sub.2).sub.b OR"].sub.4',b a polymer resulting from the partial hydrolysis of at least one monomer of the formula Ti(OR").sub.
    Type: Grant
    Filed: May 5, 1975
    Date of Patent: June 22, 1976
    Assignee: Rhone-Poulenc S.A.
    Inventors: Louis Ceyzeriat, Michel Letoffe