Flameproof Patents (Class 260/DIG24)
  • Patent number: 3965212
    Abstract: A flame-resistant resin composition consisting essentially of 100 parts by weight of polytetramethylene terephthalate, 3 to 40 parts by weight of a flame retardant represented by the general formula, ##SPC1##Wherein n + m is a number of 0 to 10; X is a bromine or chlorine atom; and i, j, k and l are individually an integer of 1 to 4, and antimony trioxide, the weight ratio of said flame retardant to said antimony trioxide being in the range of from 0.25 to 6. This composition is excellent in mechanical properties, thermal properties and moldability, and causes no spread of fire to other materials even when dripped at the time of combustion.
    Type: Grant
    Filed: December 3, 1974
    Date of Patent: June 22, 1976
    Assignee: Mitsubishi Rayon Co., Ltd.
    Inventors: Kazumasa Kamada, Ryoji Handa, Masafumi Hongo
  • Patent number: 3965054
    Abstract: The present invention provides a foamable polyolefin composition comprising a polyolefin, a crosslinking agent, a blowing agent decomposable at temperatures higher than the decomposition temperature of said crosslinking agent and a gas trapping agent as well as a method for manufacturing foamed polyolefin from said foamable polyolefin composition.
    Type: Grant
    Filed: October 14, 1975
    Date of Patent: June 22, 1976
    Assignee: The Furukawa Electric Co., Ltd.
    Inventors: Akio Nojiri, Naonori Shiina, Hlroyuki Nakae, Hideyo Ueno, Isamu Namiki
  • Patent number: 3963790
    Abstract: Non-inflammable filaments having good physical characteristics are disclosed, wherein the filaments have a chlorine content of 25-40% by weight and a sticking temperature of at least 215.degree.C, and a shrinkage of less than 32% when subjected to steam at 130.degree.C in the free or unrestrained state. The filaments are formed by spinning a mixture of incompatible polymers, one polymer, used in an amount of 50-99% by weight, containing 79.5 to 58 weight percent of acrylonitrile units, 20-40 weight percent of vinylidene chloride units and 0.5 to 2 weight percent of a comonomer which enhances dyeability, and the other copolymer, used in an amount of from 1-50 weight percent, containing from 20-50 percent by weight of acrylonitrile units and 50-80 percent of vinylidene chloride units.The filaments may be used in textile applications, such as for clothing, furniture upholstery, and the like.
    Type: Grant
    Filed: September 3, 1974
    Date of Patent: June 15, 1976
    Assignee: Rhone-Poulenc-Textile
    Inventor: Paul Couchoud
  • Patent number: 3963669
    Abstract: Glass-fiber-reinforced molding compositions of reduced flammability consisting of (A) a linear saturated polyester resin, (B) from 10 to 60 per cent by weight of glass fibers and (C) from 3 to 30 per cent by weight of a flame retardant. The compositions contain from 2 to 20 per cent by weight, based on the total weight of the molding composition, of a particulate water-insoluble silicate having a bulk density of more than 100 g/l, which prevents dripping of the composition when in contact with an open flame.
    Type: Grant
    Filed: February 13, 1975
    Date of Patent: June 15, 1976
    Assignee: BASF Aktiengesellschaft
    Inventors: Rolf Wurmb, Joachim Kunde, Wolfgang Seydl
  • Patent number: 3962194
    Abstract: Permanently flame resistant filaments and fibers are produced from synthetic linear polyesters in which about 5 to 15 mol% of the acid component of the polyester consist of phosphinic acid structural units of the formula ##EQU1## in which R, R.sub.1 and R.sub.2 stand for organic radicals which may contain hetero atoms, preferably halogen, oxygen or sulfur. The filaments and fibers can be well dyed deep shades and are suitable in all fields of application where textiles which are hard to inflame are desired.
    Type: Grant
    Filed: February 10, 1975
    Date of Patent: June 8, 1976
    Assignee: Hoechst Aktiengesellschaft
    Inventors: Ulrich Bollert, Hans-Jerg Kleiner, Walter Herwig
  • Patent number: 3962170
    Abstract: Latex compositions comprising carboxylated styrene-butadiene-vinylidene chloride copolymer latices wherein the latex consists essentially of 15 to 45% styrene, 25 to 50% butadiene, 25 to 40% vinylidene chloride and 0.5 to 10% copolymerizable carboxylic acid and a flame retardant additive exhibit improved flame retardant properties for use in carpet and floor covering applications.
    Type: Grant
    Filed: October 16, 1974
    Date of Patent: June 8, 1976
    Assignee: The Goodyear Tire & Rubber Company
    Inventor: Adolf Antony Mally
  • Patent number: 3962347
    Abstract: Method at recovery of pure 3,3,7,7-tetrahydroxymethyl-5-oxanonane from a distillation residue obtained at the production of trimethylolpropane, wherein the 3,3,7,7-tetrahydroxymethyl-5-oxanonane is crystallized by a simple crystallization from a salt containing aqueous solution of the distillation residue having a specially favorable salt proportion.
    Type: Grant
    Filed: October 16, 1973
    Date of Patent: June 8, 1976
    Assignee: Perstorp AB
    Inventor: Kurt S. Herz
  • Patent number: 3961110
    Abstract: Phosphorus- and nitrogen-containing polymers, solubilized by hydroxymethylphosphonium salts and formaldehyde, were allowed to react with phenol, alkyl substituted phenols, or halogen substituted phenols which contain one or more hydrogens ortho or para to the phenolic hydroxyl group to (a) prepare flame-resistant polymers and (b) prepare flame-, glow-, wrinkle-, and shrink-resistant woven and knit textiles which contain 25% or more cellulosic fibers.
    Type: Grant
    Filed: August 22, 1974
    Date of Patent: June 1, 1976
    Assignee: The United States of America as represented by the Secretary of Agriculture
    Inventors: Donald J. Daigle, Armand B. Pepperman, Jr., Sidney L. Vail
  • Patent number: 3957905
    Abstract: A fire retardant thermoplastic polyester type block copolymer composition, which comprises (a) a thermoplastic polyester type block copolymer comprising a hard polyester segment having a high melting point and a soft polymer segment having a low melting point and a molecular weight of 400 to 6,000 and (b) a mixture of one or more kinds of halogenated bisphenyl compounds and an organic or inorganic antimony compound in a ratio of 1:0 to 1:3 by weight, and optionally one or more kinds of alkylphenol derivatives and/or an epoxy compound having 1 to 20 % by weight of oxirane oxygen.
    Type: Grant
    Filed: January 17, 1974
    Date of Patent: May 18, 1976
    Assignee: Toyo Boseki Kabushiki Kaisha
    Inventors: Misao Sumoto, Hiroshi Imanaka, Masaharu Shirai
  • Patent number: 3955987
    Abstract: Intumescent compositions are described which when deposited on a substrate protect the substrate against heat and fire damage for an appreciable time, and these compositions are readily removed from the substrate by water washing or water scrubbing both before and after intumescing. Another advantage of these compositions is that they give off very little smoke when exposed to heat and fire. The most effective of these compositions comprise monoammonium phosphate and/or diammonium phosphate as a heat- and fireproofing agent, urea and/or cyanoguanidine (dicyandiamide) as a gas forming or gas generating agent to promote the intumescence, sucrose (sugar) together with the phosphate to promote initial intumescence at low temperature and titanium dioxide as a heat-reflecting agent. Certain possible alternatives to the compounds named above are also named.
    Type: Grant
    Filed: April 19, 1974
    Date of Patent: May 11, 1976
    Assignee: Monsanto Research Corporation
    Inventors: John L. Schaar, James A. Ellard, John Mann Butler
  • Patent number: 3956243
    Abstract: Composition for flameproofing organic fibre material which contains at least1. a tetrakis-(hydroxymethyl)-phosphonium compound, its self-condensation product or its condensation product with a reactive nitrogen compound2. an aliphatic amide or an imidazole or an imidazoline as agent for imparting a soft handle3. a methylolated amino groups containing 1,3,5-triazine and, optionally,4. an optionally methylolated and esterified derivative of a urea and, optionally,5. a low molecular amine.These compositions yield flameproof finishes paired with a soft handle especially on polyester-cotton blends.
    Type: Grant
    Filed: December 7, 1973
    Date of Patent: May 11, 1976
    Assignee: Ciba-Geigy Corporation
    Inventors: Rudolf Loss, Rene Berini, Armin Hiestand, Peter Hofmann, Hermann Nachbur
  • Patent number: 3956233
    Abstract: Flame retardant elastomeric compositions comprised of either spandex type polyurethane having incorporated into the polymer chain halogen containing polyols, conventional spandex type polyurethanes in physical admixture with flame retardant additives or fluoroelastomeric resins in physical admixture with flame retardant additives, methods of preparing fibers of the flame retardant elastomeric materials and articles of manufacture comprised of the flame retardant elastomeric materials and non-elastic materials such as polybenzimidazoles, fiberglass, nylons, etc.
    Type: Grant
    Filed: June 28, 1973
    Date of Patent: May 11, 1976
    Assignee: The United States of America as represented by the Administrator of the National Aeronautics and Space Administration
    Inventors: James C. Administrator of the National Aeronautics and Space Administration, with respect to an invention of Fletcher, John T. Howarth, Suresh Sheth, Kenneth R. Sidman, Arthur A. Massucco
  • Patent number: 3955028
    Abstract: Compounds of the formula:[(BrCH.sub.2).sub.3 CCH.sub.2 O].sub.2 P(O)Rwherein R is a functional group selected from the group consisting of --CH=CH.sub.2, --CH.sub.2 X, --OR'OC(O)CH=CH.sub.2, --OR'OC(O)C(CH.sub.3)=CH.sub.2, --O(R'O).sub.n H, --OH, --Cl, and NR"R'", wherein R' is a C.sub.1 -C.sub.4 alkylene group, wherein R" and R'" are the same or different and are selected from the group consisting of hydrogen, lower alkyl, e.g. C.sub.1 -C.sub.8, preferably C.sub.1 -C.sub.4, phenyl, hydroxyalkyl, e.g., hydroxy C.sub.1 -C.sub.8, or, preferably hydroxy C.sub.1 -C.sub.4, and allyl groups, wherein X is selected from the group consisting of chlorine and bromine and wherein n is an integer between 1 and 20 are disclosed. These compounds have flame retardancy characteristics and are useful either as flame retardant additives or as reactive flame retardants which can react to confer durable flame retardancy on textiles or other polymer products.
    Type: Grant
    Filed: July 18, 1974
    Date of Patent: May 4, 1976
    Assignee: Stauffer Chemical Company
    Inventor: Edward D. Weil
  • Patent number: 3953540
    Abstract: A resinous composition suitably used for molding purposes composed of an acrylonitrile-chlorinated polyethylene-styrene ternary resin and antimony trioxide and possessing high flame retardancy and superior antistatic properties.
    Type: Grant
    Filed: May 28, 1974
    Date of Patent: April 27, 1976
    Assignee: Showa Deuko Kabushiki Kaisha
    Inventors: Shoichiro Takezoe, Masao Ogawa, Junichi Nakamura
  • Patent number: 3953650
    Abstract: A line cord of a telephone handset having individually insulated conductors is jacketed with an extrudable flexible clear flame retardant composition which includes a polyvinyl chloride resin (PVC), 10 to 55 parts by weight per 100 parts by weight of the PVC of a phthalate plasticizer, 3 to 50 parts by weight per 100 parts by weight of the PVC of a phosphate plasticizer, 2 to 5 parts by weight per 100 parts by weight of the PVC of a metallic stabilizer, 0.25 to 1.0 part by weight per 100 parts by weight of the PVC of a lubricant, 0.25 to 1.0 part by weight per 100 parts by weight of the PVC of an ultraviolet absorber, 1 to 4 parts by weight per 100 parts by weight of the PVC of an epoxy resin, and 1 to 8 parts by weight per 100 parts by weight of the PVC of an epoxy plasticizer.
    Type: Grant
    Filed: September 30, 1974
    Date of Patent: April 27, 1976
    Assignee: Western Electric Company, Inc.
    Inventors: Earl Salvator Sauer, William Charles Vesperman
  • Patent number: 3951900
    Abstract: A stable adhesive composition containing primarily a styrene-butadiene binder, calcium sulfate dihydrate as a combination filler and fire-retardant, a nonionic wetting agent and a non-phosphate sequestering agent.
    Type: Grant
    Filed: December 26, 1973
    Date of Patent: April 20, 1976
    Assignee: National Gypsum Company
    Inventor: Wesley W. Bath
  • Patent number: 3950301
    Abstract: Ultraviolet light stable polyester resin compositions are provided by this invention. These compositions include as the stabilizer system, a stabilizing amount of a hydroxybenzotriazole ultraviolet light absorber.
    Type: Grant
    Filed: August 1, 1974
    Date of Patent: April 13, 1976
    Assignee: General Electric Company
    Inventors: Karl J. Balog, Donald I. Craft
  • Patent number: 3947421
    Abstract: Self-extinguishing molding compositions based on polybutylene terephthalate which do not drip flaming particles on exposure to a flame and which contain a compound containing halogen, which is stable under the conditions required for processing the melt, and a synergistically active metal compound, are obtained by incorporation of a magnesium silicate of the chrysotile type into the polycondensate.
    Type: Grant
    Filed: January 17, 1974
    Date of Patent: March 30, 1976
    Assignee: BASF Aktiengesellschaft
    Inventor: Wolfgang Seydl
  • Patent number: 3945941
    Abstract: A minor amount of a radical trap, that is, an organic compound readily reacting with an organic radical, when combined with a polyolefin having a melt index of from about 0.2 to about 10, can be associated with 70 per cent tertiary butyl hydroperoxide (containing about 30 per cent water). In the event of accidental conflagration of the combination, the combustion continues at a moderate rate, thereby avoiding the propensity toward troublesomely rapid burning of unmodified aqueous 70 per cent TBHP. Container liners should have a polyolefin thickness of 0.7 to 7 mm, the polyolefin containing such radical trap in a concentration of from about 0.1 to about 5 per cent, generally 0.2 to 2 per cent. If particulate polyolefin is used, the radical trap concentration should be from about 10 to about 100,000 parts per million parts of aqueous TBHP. A concentration of polyolefin particles from about 0.6 per cent to about 6 per cent by weight of the TBHP is suitable.
    Type: Grant
    Filed: January 7, 1975
    Date of Patent: March 23, 1976
    Assignee: Oxirane Corporation
    Inventors: Alfred E. Borchert, Eugene C. Capaldi, Donnell A. Ballard
  • Patent number: 3944384
    Abstract: Flame-retardant acrylic filaments containing a flame retardant which is the reaction product of a dibasic acid amide, an oxyacid of phosphorus and a polyhydroxy alcohol, the flame retardant being bound to the acrylic filaments by a cross-linking agent. The filaments are made flame-retardant by applying the flame retardant and cross-linking agent to the filaments and subsequently heating the filaments to chemically bind the flame retardant to the acrylic filaments.
    Type: Grant
    Filed: November 4, 1974
    Date of Patent: March 16, 1976
    Assignee: Courtaulds Limited
    Inventor: David John Poynton
  • Patent number: 3943195
    Abstract: Thermoplastic molding material based on styrene polymers and olefin polymers which have been flameproofed with an organic bromine compound. Brominated oligomers or polymers of dialkylbenzenes, trialkylbenzenes or tetraalkylbenzenes serve as flameproofing agents. The molding material may be processed into self-extinguishing moldings.
    Type: Grant
    Filed: November 21, 1974
    Date of Patent: March 9, 1976
    Assignee: BASF Aktiengesellschaft
    Inventors: Herbert Naarmann, Klaus Penzien
  • Patent number: 3943191
    Abstract: Novel compositions are disclosed which include a polyphenylene ether resin and an alkenyl aromatic resin modified with an EPDM rubber. Also included with the scope of this invention are reinforced and flame-retardant compositions of said polyphenylene ether resin and said alkenyl aromatic resin modified with an EPDM rubber.
    Type: Grant
    Filed: October 1, 1973
    Date of Patent: March 9, 1976
    Assignee: General Electric Company
    Inventors: Glenn D. Cooper, Visvaldis Abolins
  • Patent number: 3943085
    Abstract: Self-extinguishing, thermoplastic polymer compositions are prepared by the intimate admixture of a thermoplastic polymer with a copolymer of a halogen containing ethylenically unsaturated monomer and a phosphorus containing vinyl monomer, particularly a bis(hydrocarbyl)vinylphosphonate. The thus modified thermoplastic polymers display a high degree of flame retardance without any substantial changes in their physical properties including, for example, their clarity and hardness and the resulting compositions may be safely employed in any application requiring their possible exposure to fire or high temperatures.
    Type: Grant
    Filed: February 7, 1975
    Date of Patent: March 9, 1976
    Assignee: Stauffer Chemical Company
    Inventors: Paul Kraft, Siegfried Altscher
  • Patent number: 3943198
    Abstract: Polyalkylene glycol vinyl phosphates having the formula: ##EQU1## ARE PROVIDED WHEREIN R is a polyalkylene glycol residue, m and n are integers from about 1 to about 100, R' is selected from the group consisting of hydrogen, lower alkyl, and lower haloalkyl, provided that if R' is lower haloalkyl, it is not monohalo-substituted on its alpha carbon atom, and Z and Y are selected from the group consisting of hydrogen, lower alkyl and lower haloalkyl. They are formed by reacting the transesterification product of a tertiary phosphite and a polyalkylene glycol with a carbonyl compound having halogen monosubstitution on one of its alpha carbon atoms. These compositions can be used to flame retard a number of normally flamable substrates.
    Type: Grant
    Filed: July 22, 1974
    Date of Patent: March 9, 1976
    Assignee: Stauffer Chemical Company
    Inventor: Kyung S. Shim
  • Patent number: 3943076
    Abstract: Addition products of polyepoxides which have proved to be excellent flame-retardants for plastic foams such as polyurethane foams are disclosed.
    Type: Grant
    Filed: January 27, 1975
    Date of Patent: March 9, 1976
    Assignee: Owens-Corning Fiberglas Corporation
    Inventors: Reuben H. Bell, Kevin M. Foley
  • Patent number: 3943194
    Abstract: Flameproof moulding compositions, which are based on polyolefins and made from a pulverulent blend comprising a polyolefin as its essential ingredient and a plurality of flame-retardant ingredients. The flame-retardant ingredients comprise red phosphorus and at least one organic nitrogen compound which carbonizes after inflammation. The moulding compositions contain the flame-retardant ingredients in a total proportion of at most about 30 weight %. Red phosphorus and organic nitrogen compound are used in a quantitative ratio between 99:1 and 1:99.
    Type: Grant
    Filed: October 1, 1974
    Date of Patent: March 9, 1976
    Assignees: Hoechst Aktiengesellschaft, Ruhrchemie Aktiengesellschaft
    Inventors: Franz-Josef Dany, Joachim Wortmann, Peter Munch, Gunther Braun
  • Patent number: 3941752
    Abstract: Flame-repellant linear polyesters are obtained by incorporating by condensation phosphorus-compounds having the formula ##EQU1## wherein R and R.sub.1 are organic radicals which may also contain hereto atoms into the linear polyesters, preferably those from terephthalic acid and ethylene glycol. These polyesters are materials of which flame-repellent filaments, fibers, sheets, press-moulded and injection-moulded articles may be made. Products of the invention can be used whereever especially acute risks of ignition and fire exist.
    Type: Grant
    Filed: September 13, 1974
    Date of Patent: March 2, 1976
    Assignee: Hoechst Aktiengesellschaft
    Inventors: Hans-Jerg Kleiner, Manfred Finke, Ulrich Bollert, Walter Herwig
  • Patent number: 3939107
    Abstract: Novel stable-in-use aminoplast resin binder solutions comprising aqueous solutions of predominantly a urea-formaldehyde resin having a formaldehyde to urea ratio of less than 2.0, from about 40 to 56% by weight dissolved ammonium polyphosphate reacted with 5 to 12.5 percent by weight formaldehyde and not more than 30% by weight water. Preferred aminoplast resin binder solutions also contain a methylolated melamine-formaldehyde resin. A novel process for the production of the stable aminoplast resin binder solutions containing high percentages of ammonium polyphosphates and suitable for production of fire-retardant particle board is disclosed.
    Type: Grant
    Filed: September 6, 1974
    Date of Patent: February 17, 1976
    Assignee: Monsanto Company
    Inventor: Gordon E. Brown
  • Patent number: 3937756
    Abstract: A polymerizable fire retardant unsaturated polyester resin composition is prepared by reacting a dicarboxylic acid with a polyhydric compound and an effective amount of 4,5-dibromohexahydrophthalic anhydride or its corresponding acid. The resulting unsaturated polyester resin composition when mixed with a polymerizable monomer containing terminal unsaturation and cured exhibits improved flame resistance at low bromine concentrations.
    Type: Grant
    Filed: May 24, 1974
    Date of Patent: February 10, 1976
    Assignee: Jefferson Chemical Company, Inc.
    Inventors: Howard Paul Klein, Harold George Waddill
  • Patent number: 3936414
    Abstract: This specification discloses that certain polychlorinated or polybrominated aromatic hydrocarbon compounds can be incorporated in thermosetting polymer compositions to make the thermosetting compositions flame retardant without injuring the desirable physical and electrical properties of the thermosetting compositions when in the thermoset state. These polyhalogenated aromatic hydrocarbons are apparently caused to react into the thermosetting composition, provided there is a minimum of 1 mol of a polyunsaturated monomer containing carbon to carbon unsaturation for each 3 mols of polychlorinated aromatic hydrocarbons.
    Type: Grant
    Filed: December 4, 1970
    Date of Patent: February 3, 1976
    Assignee: FMC Corporation
    Inventors: Carl Leonard Wright, Harry Hoyt Beacham
  • Patent number: 3936400
    Abstract: Normally flammable foamed polyester resins (a) are rendered flame retardant by combination with (b) a flame retardant amount of (i) an aromatic carbonate copolymer, from 25 to 75 wt. % of the repeating units comprising chloro- or bromo-substituted dihydric phenol units; (ii) an aromatic carbonate homopolymer having repeating units comprising chloro- or bromo-substituted dihydric phenol units in combination with an aromatic carbonate homopolymer having repeating dihydric phenol units; or (iii) a combination of (i) with an aromatic carbonate homopolymer having repeating dihydric phenol units, and (c) an antimony-containing compound.
    Type: Grant
    Filed: July 5, 1974
    Date of Patent: February 3, 1976
    Assignee: General Electric Company
    Inventor: Allen D. Wambach
  • Patent number: 3933706
    Abstract: A nonflammable binder composition having good properties, such as excellent adhesiveness, flexibility, storage stability and nonflammability, comprises a water-soluble silicate and a vinyl polymer emulsion which is prepared by emulsion polymerization of polymerizable vinyl monomer using, as an emulsifying agent, a neutralization product of water-soluble resin containing carboxyl groups.
    Type: Grant
    Filed: October 8, 1974
    Date of Patent: January 20, 1976
    Assignee: Kansai Paint Company, Ltd.
    Inventors: Iwao Momiyama, Tatsuo Fukushima
  • Patent number: 3933689
    Abstract: The addition of a low softening point glass of Tg 300.degree.C and optionally a blowing agent, to a reinforced thermosetting composite material gives fire retardant properties to the product. Smoke emission on burning is less than for halogenated fire retardant additives. A preferred embodiment is GRP sheet containing a powdered phosphate glass and a blowing agent.
    Type: Grant
    Filed: May 23, 1973
    Date of Patent: January 20, 1976
    Assignee: Imperial Chemical Industries Limited
    Inventors: Neil Hunter Ray, Bryan Shaw, Bruce Cochran Lane
  • Patent number: 3931059
    Abstract: A compound adapted to be used to advantage as a catalyst for making carbodiimide foams is prepared by a process whereinA. a phosphetane oxide or phosphetane sulphide of the general Formulae I and II: ##EQU1## wherein X represents a C.sub.1 -C.sub.18 alkyl, C.sub.2 -C.sub.18 alkenyl, C.sub.6 -C.sub.14 aryl, C.sub.7 -C.sub.20 aralkyl, C.sub.1 -C.sub.18 alkoxy or C.sub.6 -C.sub.14 aroxy group andR.sup.1 to R.sup.6 represent hydrogen and/or C.sub.1 -C.sub.4 alkyl groups and is reacted withB. a mono-, di- and/or polyhydric alcohol having a molecular weight of about 32 to about 250, a protonic acid which has a pH of between 1 and 8 in N/10 aqueous solution, a metal salt or an acid chloride.
    Type: Grant
    Filed: August 19, 1974
    Date of Patent: January 6, 1976
    Assignee: Bayer Aktiengesellschaft
    Inventors: Andrea La Spina, Werner Dietrich, Reinhard Schliebs
  • Patent number: 3931095
    Abstract: A fire retardant thermosetting resin composition containing tricalcium aluminate hexahydrate as a filler.
    Type: Grant
    Filed: June 28, 1974
    Date of Patent: January 6, 1976
    Assignees: Nippon Kayaku K.K., Denki Kagaku Kogyo Kabushiki Kaisha
    Inventors: Renichi Kondo, Koji Nakagawa, Makoto Fukuda, Ikuji Kishi, Tateki Ohtsuki