Patents by Inventor Sunao MIKAMI

Sunao MIKAMI 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: 11761121
    Abstract: A method for producing a polyacetal fiber that presents an improved whiteness unevenness is provided. According to one embodiment, there is provided a polyacetal fiber production method that yields a polyacetal fiber using an oxymethylene copolymer having a melt index, at 190° C. under a load of 2.16 kg, of 5-60 g/10 min, wherein the production method includes taking off the polyacetal fiber from the discharge nozzle of a spinning apparatus, and drawing the taken-off polyacetal fiber. The tensile elongation E1 of the polyacetal fiber after the taking off is 20%-500%; the tensile elongation E2 of the polyacetal fiber after the drawing is 10%-100%; E1?E2; and the single fiber thickness of the polyacetal fiber after the drawing is 0.7-5.0 denier.
    Type: Grant
    Filed: June 8, 2018
    Date of Patent: September 19, 2023
    Assignee: MITSUBISHI GAS CHEMICAL COMPANY, INC.
    Inventors: Akira Ito, Daisuke Sunaga, Sunao Mikami
  • Patent number: 11441242
    Abstract: The present invention provides a method for manufacturing a polyacetal fiber in which whiteness irregularity is improved. One embodiment of the present invention provides a method for manufacturing a polyacetal fiber, wherein the method includes a discharge step, a takeup step, a stretching step, and a winding step, the steps being continuously performed, an oxymethylene copolymer being used as the raw material of the polyacetal fiber, the oxymethylene copolymer having an oxymethylene unit and an oxyethylene unit, the content of the oxyethylene unit being 0.5-7.0 moles to 100 moles of the oxymethylene unit, the roller temperature of a stretching unit used in the stretching step being 130-155° C., and operation parameters of the method being set so as to satisfy a prescribed numerical formula.
    Type: Grant
    Filed: June 8, 2018
    Date of Patent: September 13, 2022
    Assignee: MITSUBISHI GAS CHEMICAL COMPANY, INC.
    Inventors: Akira Ito, Daisuke Sunaga, Sunao Mikami
  • Publication number: 20210388534
    Abstract: Polyacetal fibers having excellent spinning stability and uniform appearance and production methods thereof have been awaited. According to the invention, a polyacetal fiber, comprising 0.05 to 1.3 parts by mass of an inorganic filler with respect to 100 parts by mass of a polyacetal resin, in which the inorganic filler has a primary average particle size of more than 0.5 ?m and 10 ?m or less, and the polyacetal fiber has a melt flow index of 15 to 45 g/10 min, is provided.
    Type: Application
    Filed: November 25, 2020
    Publication date: December 16, 2021
    Applicant: MITSUBISHI GAS CHEMICAL COMPANY, INC.
    Inventors: Daisuke SUNAGA, Sunao MIKAMI
  • Publication number: 20200199787
    Abstract: A method for producing a polyacetal fiber that presents an improved whiteness unevenness is provided. According to one embodiment, there is provided a polyacetal fiber production method that yields a polyacetal fiber using an oxymethylene copolymer having a melt index, at 190° C. under a load of 2.16 kg, of 5-60 g/10 min, wherein the production method includes taking off the polyacetal fiber from the discharge nozzle of a spinning apparatus, and drawing the taken-off polyacetal fiber. The tensile elongation E1 of the polyacetal fiber after the taking off is 20%-500%; the tensile elongation E2 of the polyacetal fiber after the drawing is 10%-100%; E1?E2; and the single fiber thickness of the polyacetal fiber after the drawing is 0.7-5.0 denier.
    Type: Application
    Filed: June 8, 2018
    Publication date: June 25, 2020
    Applicant: MITSUBISHI GAS CHEMICAL COMPANY, INC.
    Inventors: Akira ITO, Daisuke SUNAGA, Sunao MIKAMI
  • Publication number: 20200181806
    Abstract: The present invention provides a method for manufacturing a polyacetal fiber in which whiteness irregularity is improved. One embodiment of the present invention provides a method for manufacturing a polyacetal fiber, wherein the method includes a discharge step, a takeup step, a stretching step, and a winding step, the steps being continuously performed, an oxymethylene copolymer being used as the raw material of the polyacetal fiber, the oxymethylene copolymer having an oxymethylene unit and an oxyethylene unit, the content of the oxyethylene unit being 0.5-7.0 moles to 100 moles of the oxymethylene unit, the roller temperature of a stretching unit used in the stretching step being 130-155° C., and operation parameters of the method being set so as to satisfy a prescribed numerical formula.
    Type: Application
    Filed: June 8, 2018
    Publication date: June 11, 2020
    Applicant: MITSUBISHI GAS CHEMICAL COMPANY, INC.
    Inventors: Akira ITO, Daisuke SUNAGA, Sunao MIKAMI
  • Publication number: 20160102190
    Abstract: Provided is a method for producing an oxymethylene copolymer having excellent extrusion moldability and reduced voids in a molded article without lowering the inherent performance of an oxymethylene copolymer. Provided is a method for producing an oxymethylene copolymer, including: a step for copolymerizing a monomer raw material containing trioxane and 5-7 mass % of 1,3-dioxolane relative to the trioxane, in the presence of 0.025-0.07 mmol of boron trifluoride per mol of trioxane and 0.006-2.0 mass % of sterically hindered phenol relative to the trioxane; a step for adding a polymerization terminator to the reaction system when the polymerization yield of this copolymer has reached 92% or higher, and terminating polymerization; and a thermal stabilization step for heating and melting the crude oxymethylene copolymer in the presence of 0.05-5 mass % of an antioxidant and 0.005-5 mass % of a nitrogen-containing compound relative to the crude oxymethylene copolymer.
    Type: Application
    Filed: May 23, 2014
    Publication date: April 14, 2016
    Applicant: MITSUBISHI GAS CHEMICAL COMPANY, INC.
    Inventors: Akira ITO, Sunao MIKAMI