Patents by Inventor Keizaburo Yamaguchi

Keizaburo Yamaguchi 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: 4783521
    Abstract: Disclosed herein are novel linear copolymers having weight average molecular weight of 500-30,000 and comprising structural units represented by the following formulae (I), (II), (III) and (IV): ##STR1## wherein R.sub.1, R.sub.2 and R.sub.3 mean individually an alkyl group having 4 or fewer carbon atoms and R.sub.4 denotes an alkyl, cycloalkyl, aralkyl or phenyl group, and multivalent metal salts thereof in each of which the multivalent metal forms the multivalent metal salt between carboxyl groups within the same molecule of the copolymer or between different molecules of the copolymer; color-developing agents comprising multivalent metal-modified resins of the copolymers; and color-developing sheets obtained by coating the color-developing agents on their surfaces.
    Type: Grant
    Filed: January 16, 1987
    Date of Patent: November 8, 1988
    Assignee: Mitsui Toatsu Chemicals, Incorporated
    Inventors: Akihiro Yamaguchi, Keizaburo Yamaguchi, Yoshimitsu Tanabe, Makoto Asano, Masaru Wada
  • Patent number: 4769463
    Abstract: Noval diamines, 2,6-bis(3-aminophenoxy)pyridine and 2,6-bis-(4-aminophenoxy)pyridine, are provided and the method of their preparation is disclosed. These diamines are useful as raw materials for polyimide.These diamines can be prepared by the reaction of 2,6-dichloropyridine or 2,6-dibromopyridine with 3-aminophenol or 4-aminophenol in aprotic polar solvents in the presence of bases.Besides, 2,6-bis(3-aminophenoxy)pyridine can also be prepared by the reaction of 2,6-dicholorpyridine or 2,6-dibromopyridine with 3-nitrophenol, followed by reducing resultant 2,6-bis(3-nitrophenoxy)pyridine.
    Type: Grant
    Filed: March 11, 1987
    Date of Patent: September 6, 1988
    Assignee: Mitsui Toatsu Chemicals, Inc.
    Inventors: Keizaburo Yamaguchi, Kenichi Sugimoto, Yukihiro Yoshikawa, Yoshimitsu Tanabe, Akihiro Yamaguchi
  • Patent number: 4754068
    Abstract: 1,3-Bis(3-aminophenoxy)-5-halogenobenzenes represented by the formula (I): ##STR1## wherein X is a chlorine or bromine atom, are novel compounds and can be prepared by reacting trihalogenobenzenes represented by the formula (II): ##STR2## wherein X.sub.1, X.sub.2 and X.sub.3 are each a chlorine or bromine atom, with 3-aminophenol in the presence of a dehydrohalogenating agent.
    Type: Grant
    Filed: December 15, 1986
    Date of Patent: June 28, 1988
    Assignee: Mitsui Toatsu Chemicals, Inc.
    Inventors: Keizaburo Yamaguchi, Yukihiro Yoshikawa, Yoshimitsu Tanabe, Kenichi Sugimoto, Akihiro Yamaguchi
  • Patent number: 4751328
    Abstract: Aminobenzylamines are produced by catalytically reducing o-, m- or p-nitrobenzaldoxime in an organic solvent in the presence of a compound selected from the group consisting of (a) boric acid, phosphoric acid and/or anhydrides thereof, (b) CO.sub.2 gas and (c) an organic acid. The starting material, nitrobenzaldoxime is produced by reaction of the corresponding nitrobenzaldehyde with hydroxylamine.
    Type: Grant
    Filed: November 24, 1986
    Date of Patent: June 14, 1988
    Assignee: Mitsui Toatsu Chemicals, Inc.
    Inventors: Keizaburo Yamaguchi, Kenichi Sugimoto, Yoshimitsu Tanabe, Midori Yamazaki, Akihiro Yamaguchi
  • Patent number: 4724268
    Abstract: A crude 3,3'-dinitrodiphenyl compound selected from 3,3'-dinitrodiphenylsulfone or 3,3'-dinitrobenzophenone is purified by reacting the crude 3,3'-dinitrodiphenyl compound with a lower alcohol in the presence of a base so as to convert practically the isomer or isomers, which contain one or more nitro groups at the ortho- or/and para-positions, only into the corresponding alkoxy compound or compounds thereof and then separating the alkoxy compound or compounds.
    Type: Grant
    Filed: July 7, 1986
    Date of Patent: February 9, 1988
    Assignee: Mitsui Toatsu Chemicals, Incorporated
    Inventors: Keizaburo Yamaguchi, Kenichi Sugimoto, Yoshimitsu Tanabe, Teruyuki Nagata, Akihiro Yamaguchi
  • Patent number: 4701567
    Abstract: A novel process for producing 6,6'-dihydroxy-3,3,3',3'-tetramethyl-1,1'-spirobiindane of the formula (1) ##STR1## which comprises heat-treating 2,2-bis(4-hydroxyphenyl)propane in the presence of a superacid-type resin or a perfluoroalkanesulfonic acid.
    Type: Grant
    Filed: June 26, 1986
    Date of Patent: October 20, 1987
    Assignee: Mitsui Toatsu Chemicals, Inc.
    Inventors: Yoshimitsu Tanabe, Keizaburo Yamaguchi, Yukihiro Yoshikawa, Kenichi Sugimoto, Akihiro Yamaguchi
  • Patent number: 4692554
    Abstract: A process for producing 1,3-bis(3-aminophenoxy)-benzenes which are very useful as a monomer for heat-resistant high molecular weight polymers is provided, which process comprises dehalogenating a bis(3-aminophenoxy)-halogenobenzene by its reduction, which compound is selected from the group consisting of 1,3-bis(3-aminophenoxy)-5-halogenobenzenes, 1,3-bis(3-aminophenoxy)-2,4-dihalogenobenzenes and 1,5-bis(3-aminophenoxy)-2,4-dihalogenobenzenes, these raw material compounds being respectively obtained by reacting a 1,3,5-trihalogenobenzene, a 1,2,3,4-tetrahalogenobenzene or a 1,2,4,5-tetrahalogenobenzene with 3-aminophenol in the presence of a dehydrohalogenating agent.
    Type: Grant
    Filed: August 7, 1984
    Date of Patent: September 8, 1987
    Assignee: Mitsui Toatsu Chemicals, Inc.
    Inventors: Keizaburo Yamaguchi, Yukihiro Yoshikawa, Yoshimitsu Tanabe, Kenichi Sugimoto, Akihiro Yamaguchi
  • Patent number: 4671890
    Abstract: A composition of aminobenzylamine is provided which is mainly composed of m-aminobenzylamine and p-aminobenzylamine in either the presence or absence of a small quantity of o-aminobenzylamine, is liquid at room temperature, and is an excellent cold-setting type curing agent useful for thermosetting resin compositions.
    Type: Grant
    Filed: June 17, 1985
    Date of Patent: June 9, 1987
    Assignee: Mitsui Toatsu Chemicals, Inc.
    Inventors: Keizaburo Yamaguchi, Kenichi Sugimoto, Yoshimitsu Tanabe, Midori Yamazaki, Akihiro Yamaguchi
  • Patent number: 4618714
    Abstract: Preparation of 3,3'- or 3,4'-diaminobenzophenone by nitrating a chloronitrobenzophenone mixture obtained by the Friedel-Crafts reaction between 3- or 4-nitrobenzoyl chloride and chlorobenzene, and catalytically reducing and dechlorinating the resulting chlorodinitrobenzophenone mixture in the presence of a reduction catalyst and a dehydrochlorinating agent.
    Type: Grant
    Filed: May 2, 1983
    Date of Patent: October 21, 1986
    Assignee: Mitsui Toatsu Chemicals, Inc.
    Inventors: Keizaburo Yamaguchi, Kenichi Sugimoto, Yoshimitsu Tanabe, Saburo Kawashima, Akihiro Yamaguchi
  • Patent number: 4540818
    Abstract: Preparation of 3,3'- or 3,4'-diaminodiphenylmethane by catalytically reducing and dechlorinating, in the presence of a reduction catalyst, a dinitrobenzophenone compound having the formula ##STR1## wherein X is chlorine and attached to a position 4 or 6 on the benzene ring, and Y is hydrogen or chlorine with the proviso that when Y is hydrogen, the nitro group is attached to a position 3' or 4', and when Y is chlorine, Y is attached to a position 4' and the nitro group is attached to a position 3'.
    Type: Grant
    Filed: May 2, 1983
    Date of Patent: September 10, 1985
    Assignee: Mitsui Toatsu Chemicals, Inc.
    Inventors: Keizaburo Yamaguchi, Kenichi Sugimoto, Yoshimitsu Tanabe, Saburo Kawashima, Akihiro Yamaguchi
  • Patent number: 4482742
    Abstract: 3,3'-diamino diphenylsulfones are prepared by catalytically reducing and dehalogenating, in the presence of a reduction catalyst and a dehydrohalogenation agent, a diphenylsulfone compound of the general formula ##STR1## in which X is a halogen atom and Y is hydrogen or a halogen atom.
    Type: Grant
    Filed: April 12, 1983
    Date of Patent: November 13, 1984
    Assignee: Mitsui Toatsu Chemicals Inc.
    Inventors: Keizaburo Yamaguchi, Kenichi Sugimoto, Yoshimitsu Tanabe
  • Patent number: 4453009
    Abstract: 4-Fluorobenzophenone derivatives of 4,4'-difluorobenzophenone are produced by effecting a halogen-fluorine exchanging reaction between the corresponding 4-halogenobenzophenone derivatives or 4,4'-dihalogenobenzophenone and an alkali fluoride.The reaction is carried out by heating in an organic solvent. After distilling off the solvent from the reaction product mixture, the end product is isolated by extracting with a solvent. Alternatively the end product is isolated by distillation.
    Type: Grant
    Filed: October 8, 1982
    Date of Patent: June 5, 1984
    Assignee: Mitsui Toatsu Chemicals, Inc.
    Inventors: Akihiro Yamaguchi, Keizaburo Yamaguchi, Kenichi Sugimoto, Yoshimitsu Tanabe
  • Patent number: 4407892
    Abstract: Heat sensitive recording sheet having improved light resistance and water resistance. A developer contained therein is one or more specified metal salts of 2,2'-bisphenolsulfide, 2,2'-bisphenolsulfoxide and 2,2'-bisphenolsulfone compounds. The heat sensitive recording sheet can further contain a heat fusible material having a melting point of 50.degree. to 190.degree. C.
    Type: Grant
    Filed: July 20, 1982
    Date of Patent: October 4, 1983
    Assignee: Mitsui Toatsu Chemicals, Incorporated
    Inventors: Akihiro Yamaguchi, Keizaburo Yamaguchi, Hisamichi Murakami
  • Patent number: 4380671
    Abstract: Disclosed is a process for the preparation of 2,2'-bis(4-substituted phenol)sulfides which comprises reacting a 4-substituted phenol with sulfur dichloride in a hydrocarbon solvent at a temperature of from -10.degree. to 40.degree. C. in the presence of a Lewis acid catalyst. For example, 2,2'-bis(4-cumylphenol)-sulfide, i.e. 2,2'-bis(4-.alpha.,.alpha.-dimethyl benzyl-phenol)monosulfide, which is a novel compound can be prepared by reacting 4-cumylphenol with sulfur dichloride in benzene at a temperature of from 0.degree.to 10.degree. C. in the presence of zinc chloride.
    Type: Grant
    Filed: July 30, 1981
    Date of Patent: April 19, 1983
    Assignee: Mitsui Toatsu Chemicals, Incorporated
    Inventors: Akihiro Yamaguchi, Tadashi Kobayashi, Keizaburo Yamaguchi, Hisamichi Murakami
  • Patent number: 4312522
    Abstract: This invention discloses a heat sensitive recording sheet which contains, as a developer, at least one of the compounds represented by the general formula ##STR1## where R represents hydrogen, an alkyl radical of from 1 to 12 carbon atoms, a cycloalkyl radical of from 3 to 10 carbon atoms, an aralkyl radical of from 7 to 10 carbon atoms, and a phenyl radical, and may be identical to or different from each other, n is zero, or an integer of 1 or 2.The heat sensitive recording sheet of this invention has a sharper rise in developed color density and is advantageous for its handling and storage as well as gives a developed color image having an excellent fastness to light and water resistance in addition to very little decrease in density of the developed color image with time.
    Type: Grant
    Filed: August 14, 1980
    Date of Patent: January 26, 1982
    Assignee: Mitsui Toatsu Chemicals, Inc.
    Inventors: Akihiro Yamaguchi, Keizaburo Yamaguchi, Hisamichi Murakami
  • Patent number: 4287366
    Abstract: A process for preparing bisphenol sulfone derivatives represented by the general formula (I) ##STR1## where R stands for hydrogen, a halogen, an alkyl radical, a cycloalkyl radical, an aryl radical, an aralkyl radical, hydroxyl group, an alkoxy radical, allyloxy group, carboxyl group, or a carboalkoxy radical, m is an integer of from 1 to 3, and when m is 2 or more, R may be identical to or different from each other, and adjacent Rs may be combined to form a ring, by oxidizing with hydrogen peroxide a compound represented by the general formula (II) ##STR2## where R and m have the same meanings as defined for the formula (I), and n is zero or 1, in the presence of an alkali in an amount more than the equimolar amount thereof relative to said compound in water and/or an organic solvent which do not form any organic peracids under reaction conditions.
    Type: Grant
    Filed: March 10, 1980
    Date of Patent: September 1, 1981
    Assignee: Mitsui Toatsu Chemicals, Inc.
    Inventors: Akihiro Yamaguchi, Keizaburo Yamaguchi, Hisamichi Murakami, Tadashi Kobayashi
  • Patent number: 4275240
    Abstract: 2,2'-Bisphenol sulfoxides are prepared by oxidizing 2,2'-bisphenol sulfides with hydrogen peroxide in the presence of such an organic solvent as not to form any organic peracids under reaction conditions.
    Type: Grant
    Filed: March 3, 1980
    Date of Patent: June 23, 1981
    Assignee: Mitsui Toatsu Chemicals, Inc.
    Inventors: Akihiro Yamaguchi, Keizaburo Yamaguchi, Hisamichi Murakami, Tadashi Kobayashi
  • Patent number: 4260179
    Abstract: A color-developing sheet for pressure-sensitive recording sheets, said sheet comprising as a color-developing agent at least one 2,2'-bisphenolsulfone zinc salt selected from compounds of the general formula ##STR1## wherein R.sub.1 and R.sub.2 are identical or different, and represent a hydrogen atom, a halogen atom, an alkyl group containing 1 to 10 carbon atoms, a cycloalkyl group containing 3 to 10 carbon atoms, an aralkyl group containing 7 to 11 carbon atoms, or a phenyl group.
    Type: Grant
    Filed: August 22, 1979
    Date of Patent: April 7, 1981
    Assignees: Mitsui Toatsu Chemicals Inc., Jujo Paper Co. Ltd.
    Inventors: Akihiro Yamaguchi, Tadashi Kobayashi, Keizaburo Yamaguchi, Kisuke Osawa, Hisamichi Murakami, Noboru Yamato, Akira Hasegawa