Patents by Inventor Yoshinobu Itoh

Yoshinobu Itoh 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: 5380783
    Abstract: A poly(arylene sulfide) resin composition in which the tendency of a poly(arylene sulfide) resin to cause metals making up molds, processing machinery, metal parts of inserts and the like to corrode has been inhibited, and which has good processability includes the poly(arylene sulfide) resin and, as a corrosion inhibitor, at least one substance selected from the group consisting of a metallic simple substance of molybdenum, oxoacids of molybdenum, alkali metal salts of the oxoacids of molybdenum, alkaline earth metal salts of the oxoacids of molybdenum, the ammonium salts of the oxoacids of molybdenum, the zinc salts of the oxoacids of molybdenum, a metallic simple substance of tungsten, oxoacids of tungsten, alkali metal salts of the oxoacids of tungsten, alkaline earth metal salts of the oxoacids of tungsten, the ammonium salts of the oxoacids of tungsten and the zinc salts of the oxoacids of tungsten. The corrosion inhibitor being incorporated in a proportion within a range of 0.
    Type: Grant
    Filed: August 30, 1993
    Date of Patent: January 10, 1995
    Assignee: Kureha Kagaku Kogyo K.K.
    Inventors: Yoshikatsu Satake, Toshihiko Ono, Yoshinobu Itoh, Yukio Ichikawa
  • Patent number: 5268451
    Abstract: The present invention discloses a process for producing a granular polyarylene sulfide which has a high melt viscosity and a high degree of cross-linkage, becomes gel under melting and is easy to handle in the production and the fabrication thereof.The process disclosed herein comprises (1) a step (A) an initial-stage polymerization step for obtaining a polyarylene sulfide by reacting an alkali metal sulfide, a dihaloaromatic compound and a polyhaloaromatic compound, having three or more halogen substituents in a molecule, in the presence of water in an amount of 0.5 to 2.9 moles per mol of said alkali metal sulfide at a temperature in the range of 180.degree. to 235.degree. C. until the total conversion ratio of said dihalo- and polyhaloaromatic compounds reaches 50 to 98% and the melt viscosity of a polyarylene sulfide obtained at the end of the step becomes 5 to 5,000 poise, measured at 310.degree. C.
    Type: Grant
    Filed: December 3, 1992
    Date of Patent: December 7, 1993
    Assignee: Kureha Kagaku Kogyo Kabushiki Kaisha
    Inventors: Yo Iizuka, Toshio Hosokawa, Yoshinobu Itoh, Shinji Yamamoto, Kazuo Kusida, Takayuki Katto
  • Patent number: 5200500
    Abstract: The present invention discloses a process for producing a granular polyarylene sulfide which has a high melt viscosity and a high degree of cross-linkage, becomes gel under melting and is easy to handle in the production and the fabrication thereof.The process disclosed herein comprises (1) a step (A) an initial-stage polymerization step for obtaining a polyarylene sulfide by reacting an alkali metal sulfide, a dihaloaromatic compound and a polyhaloaromatic compound, having three or more halogen substituents in a molecule, in the presence of water in an amount of 0.5 to 2.9 moles per mol of said alkali metal sulfide at a temperature in the range of 180.degree. to 235.degree. C. until the total conversion ratio of said dihalo- and polyhaloaromatic compounds reaches 50 to 98% and the melt viscosity of a polyarylene sulfide obtained at the end of the step becomes 5 to 5,000 poise, measured at 310.degree. C.
    Type: Grant
    Filed: August 22, 1990
    Date of Patent: April 6, 1993
    Assignee: Kureha Kagaku Kogyo Kabushiki Kaisha
    Inventors: Yo Iizuka, Toshio Hosokawa, Yoshinobu Itoh, Shinji Yamamoto, Kazuo Kusida, Takayuki Katto