Patents Assigned to YAMAGUCHI SEIKEN KOGYO CO., LTD.
  • Publication number: 20210198524
    Abstract: Embodiments provide a polishing composition for a magnetic disk substrate, the polishing composition containing colloidal silica, at least one of a phosphorus-containing inorganic acid and a phosphorous-containing organic acid, and water. According to at least one embodiment, the colloidal silica in the polishing composition has an average particle diameter (D50) in the range of 5 to 50 nm observed by a transmission electron microscope. In measuring a volume-based particle size distribution of the colloidal silica by dynamic light scattering, when the particle size distribution is measured by adjusting a concentration of colloidal silica particles to be 0.25 mass %, the colloidal silica contains 10 vol % or less of colloidal silica particles larger than 50 nm. The polishing composition has 1 to 50 mass % of the colloidal silica, and the pH (25° C.) in the range of 0.1 to 4.0. The colloidal silica is stabilized by sodium or ammonium.
    Type: Application
    Filed: March 9, 2021
    Publication date: July 1, 2021
    Applicant: YAMAGUCHI SEIKEN KOGYO CO., LTD.
    Inventor: Junichiro ANDO
  • Patent number: 10844243
    Abstract: Embodiments relate to a polishing composition including colloidal silica, pulverized wet-process silica particles, and at least one of a nitrogen-containing organic compound and a nitrogen-containing polymer compound. According to another embodiment, the polishing composition includes colloidal silica, pulverized wet-process silica particles, and a copolymer containing a monomer having a carboxylic acid group and a monomer having a sulfonic acid group as essential monomers. According to another embodiment, the polishing composition includes colloidal silica, pulverized wet-process silica particles, a nitrogen-containing organic compound and/or a nitrogen-containing polymer compound, and a copolymer containing a monomer having a carboxylic acid group and a monomer having a sulfonic acid group as essential monomers.
    Type: Grant
    Filed: July 3, 2018
    Date of Patent: November 24, 2020
    Assignee: YAMAGUCHI SEIKEN KOGYO CO., LTD.
    Inventors: Toru Iwata, Akina Ban, Yuka Ishida
  • Patent number: 10822525
    Abstract: Embodiments provide a polishing composition containing colloidal silica, pulverized wet-process silica particles, and a water-soluble polymer compound. According to at leaset one embodiment, the water-soluble polymer compound is a copolymer containing a structural unit derived from an unsaturated aliphatic carboxylic acid and a structural unit derived from an unsaturated amide.
    Type: Grant
    Filed: March 26, 2018
    Date of Patent: November 3, 2020
    Assignee: YAMAGUCHI SEIKEN KOGYO CO., LTD.
    Inventors: Toru Iwata, Akira Sugawa
  • Patent number: 10696870
    Abstract: Embodiments provide a polishing composition for a magnetic disk substrate, which contains colloidal silica having an average primary particle size of 5 to 200 nm, fumed silica having an average particle size of 30 to 800 nm, pulverized wet-process silica particles having an average particle size of 100 to 1000 nm, and water. According to an embodiment, a ratio of the colloidal silica is 5 to 90% by mass, a ratio of the fumed silica is 5 to 90% by mass, and a ratio of the pulverized wet-process silica particles is 5 to 90% by mass with respect to all the silica particles, and a concentration of all the silica particles is 1 to 50% by mass.
    Type: Grant
    Filed: March 23, 2018
    Date of Patent: June 30, 2020
    Assignee: YAMAGUCHI SEIKEN KOGYO CO., LTD.
    Inventor: Toru Iwata
  • Patent number: 10662272
    Abstract: Embodiments provide a polishing composition for a magnetic disk substrate containing colloidal silica, a water-soluble polymer, and water. The water-soluble polymer compound is a copolymer containing a monomer having a carboxylic acid group, a monomer having an amide group, and a monomer having a sulfonic acid group as essential monomers. The water-soluble polymer compound has a weight average molecular weight of 1,000 to 1,000,000.
    Type: Grant
    Filed: October 24, 2018
    Date of Patent: May 26, 2020
    Assignee: YAMAGUCHI SEIKEN KOGYO CO., LTD.
    Inventor: Akira Sugawa
  • Patent number: 10577445
    Abstract: Embodiments relate to a polishing composition is an aqueous composition containing at least colloidal silica, wet-process silica particles, and a water-soluble polymer compound. The water-soluble polymer compound is a copolymer containing a monomer having a carboxylic acid group, a monomer having an amide group, and a monomer having a sulfonic acid group as essential monomers.
    Type: Grant
    Filed: October 24, 2018
    Date of Patent: March 3, 2020
    Assignee: YAMAGUCHI SEIKEN KOGYO CO., LTD.
    Inventor: Toru Iwata
  • Publication number: 20190119423
    Abstract: Embodiments relate to a polishing composition is an aqueous composition containing at least colloidal silica, wet-process silica particles, and a water-soluble polymer compound. The water-soluble polymer compound is a copolymer containing a monomer having a carboxylic acid group, a monomer having an amide group, and a monomer having a sulfonic acid group as essential monomers.
    Type: Application
    Filed: October 24, 2018
    Publication date: April 25, 2019
    Applicant: YAMAGUCHI SEIKEN KOGYO CO., LTD.
    Inventor: Toru IWATA
  • Publication number: 20190119422
    Abstract: Embodiments provide a polishing composition for a magnetic disk substrate containing colloidal silica, a water-soluble polymer, and water. The water-soluble polymer compound is a copolymer containing a monomer having a carboxylic acid group, a monomer having an amide group, and a monomer having a sulfonic acid group as essential monomers. The water-soluble polymer compound has a weight average molecular weight of 1,000 to 1,000,000.
    Type: Application
    Filed: October 24, 2018
    Publication date: April 25, 2019
    Applicant: YAMAGUCHI SEIKEN KOGYO CO., LTD.
    Inventor: Akira SUGAWA
  • Patent number: 10233357
    Abstract: Embodiments provide a polishing composition for a magnetic disc substrate including colloidal silica, a phosphorus-containing compound, a water-soluble polymer compound, and water. According to at least one embodiment, the water-soluble polymer compound is a copolymer having a structural unit derived from an unsaturated aliphatic carboxylic acid and a structural unit derived from an unsaturated amide.
    Type: Grant
    Filed: May 9, 2017
    Date of Patent: March 19, 2019
    Assignee: YAMAGUCHI SEIKEN KOGYO CO., LTD.
    Inventor: Junichiro Ando
  • Patent number: 10233358
    Abstract: Embodiments relate to a polishing composition for a magnetic disk substrate, where the polishing composition contains colloidal silica, a water-soluble polymer compound, and water. According to at least one embodiment, the water-soluble polymer compound has a weight average molecular weight of 20,000 to 10,000,000 and a concentration of 0.0001 to 2.0% by mass.
    Type: Grant
    Filed: August 23, 2017
    Date of Patent: March 19, 2019
    Assignee: YAMAGUCHI SEIKEN KOGYO CO., LTD.
    Inventor: Junichiro Ando
  • Publication number: 20190010358
    Abstract: Embodiments relate to a polishing composition including colloidal silica, pulverized wet-process silica particles, and at least one of a nitrogen-containing organic compound and a nitrogen-containing polymer compound. According to another embodiment, the polishing composition includes colloidal silica, pulverized wet-process silica particles, and a copolymer containing a monomer having a carboxylic acid group and a monomer having a sulfonic acid group as essential monomers. According to another embodiment, the polishing composition includes colloidal silica, pulverized wet-process silica particles, a nitrogen-containing organic compound and/or a nitrogen-containing polymer compound, and a copolymer containing a monomer having a carboxylic acid group and a monomer having a sulfonic acid group as essential monomers.
    Type: Application
    Filed: July 3, 2018
    Publication date: January 10, 2019
    Applicant: YAMAGUCHI SEIKEN KOGYO CO., LTD.
    Inventors: Toru IWATA, Akina BAN, Yuka ISHIDA
  • Publication number: 20180371293
    Abstract: Embodiments of the subject application provide a polishing composition for a magnetic disk substrate, whereby the polishing composition contains colloidal silica, at least one of a phosphorus-containing inorganic acid and an organic acid, and water. According to at least one embodiment, the colloidal silica in the polishing composition has an average particle diameter (D50) in the range of 5 to 50 nm observed by a transmission electron microscope. In measuring a volume-based particle size distribution of the colloidal silica by dynamic light scattering, when the particle size distribution is measured by adjusting a concentration of colloidal silica particles to be 0.25 mass %, the colloidal silica contains 10 vol % or less of colloidal silica particles larger than 50 nm. According to at least one embodiment, the polishing composition has 1 to 50 mass % of the colloidal silica, and the polishing composition has the pH (25° C.) in the range of 0.1 to 4.0.
    Type: Application
    Filed: June 19, 2018
    Publication date: December 27, 2018
    Applicant: YAMAGUCHI SEIKEN KOGYO CO., LTD.
    Inventor: Junichiro ANDO
  • Publication number: 20180273803
    Abstract: Embodiments provide a polishing composition for a magnetic disk substrate, which contains colloidal silica having an average primary particle size of 5 to 200 nm, fumed silica having an average particle size of 30 to 800 nm, pulverized wet-process silica particles having an average particle size of 100 to 1000 nm, and water. According to an embodiment, a ratio of the colloidal silica is 5 to 90% by mass, a ratio of the fumed silica is 5 to 90% by mass, and a ratio of the pulverized wet-process silica particles is 5 to 90% by mass with respect to all the silica particles, and a concentration of all the silica particles is 1 to 50% by mass.
    Type: Application
    Filed: March 23, 2018
    Publication date: September 27, 2018
    Applicant: YAMAGUCHI SEIKEN KOGYO CO., LTD.
    Inventor: Toru IWATA
  • Publication number: 20180215953
    Abstract: Embodiments provide a polishing composition containing colloidal silica, pulverized wet-process silica particles, and a water-soluble polymer compound. According to at leaset one embodiment, the water-soluble polymer compound is a copolymer containing a structural unit derived from an unsaturated aliphatic carboxylic acid and a structural unit derived from an unsaturated amide.
    Type: Application
    Filed: March 26, 2018
    Publication date: August 2, 2018
    Applicant: YAMAGUCHI SEIKEN KOGYO CO., LTD.
    Inventors: Toru IWATA, Akira SUGAWA
  • Publication number: 20180057712
    Abstract: Embodiments relate to a polishing composition for a magnetic disk substrate, where the polishing composition contains colloidal silica, a water-soluble polymer compound, and water. According to at least one embodiment, the water-soluble polymer compound has a weight average molecular weight of 20,000 to 10,000,000 and a concentration of 0.0001 to 2.0% by mass.
    Type: Application
    Filed: August 23, 2017
    Publication date: March 1, 2018
    Applicant: YAMAGUCHI SEIKEN KOGYO CO., LTD.
    Inventor: Junichiro Ando
  • Patent number: 9862863
    Abstract: Embodiments of the invention provide a polishing composition including colloidal silica having an average particle size of 5 to 200 nm and pulverized wet-process silica particles having an average particle size of 0.1 to 1.0 ?m, wherein a value of the ratio of the average particle size of the wet-process silica particles to that of the colloidal silica is from 2.0 to 30.0. The polishing composition, according to various embodiments, achieves a high polishing rate and has a good surface smoothness, without the use of alumina particles.
    Type: Grant
    Filed: September 28, 2016
    Date of Patent: January 9, 2018
    Assignee: YAMAGUCHI SEIKEN KOGYO CO., LTD.
    Inventors: Toru Iwata, Akira Sugawa
  • Patent number: 9856401
    Abstract: Embodiments of the invention provide a polishing composition including colloidal silica, pulverized wet-process silica particles, and a water-soluble polymer compound, wherein the water-soluble polymer compound is a polymer or copolymer having a constituent unit derived from an unsaturated aliphatic carboxylic acid. Various embodiments achieve a high polishing rate and obtain a good surface smoothness and end-face shape without the use of alumina particles.
    Type: Grant
    Filed: September 28, 2016
    Date of Patent: January 2, 2018
    Assignee: YAMAGUCHI SEIKEN KOGYO CO., LTD.
    Inventors: Toru Iwata, Akira Sugawa
  • Publication number: 20170321086
    Abstract: Embodiments provide a polishing composition for a magnetic disc substrate including colloidal silica, a phosphorus-containing compound, a water-soluble polymer compound, and water. According to at least one embodiment, the water-soluble polymer compound is a copolymer having a structural unit derived from an unsaturated aliphatic carboxylic acid and a structural unit derived from an unsaturated amide.
    Type: Application
    Filed: May 9, 2017
    Publication date: November 9, 2017
    Applicant: YAMAGUCHI SEIKEN KOGYO CO., LTD.
    Inventor: Junichiro ANDO
  • Publication number: 20170015867
    Abstract: Embodiments of the invention provide a polishing composition including colloidal silica having an average particle size of 5 to 200 nm and pulverized wet-process silica particles having an average particle size of 0.1 to 1.0 ?m, wherein a value of the ratio of the average particle size of the wet-process silica particles to that of the colloidal silica is from 2.0 to 30.0. The polishing composition, according to various embodiments, achieves a high polishing rate and has a good surface smoothness, without the use of alumina particles.
    Type: Application
    Filed: September 28, 2016
    Publication date: January 19, 2017
    Applicant: YAMAGUCHI SEIKEN KOGYO CO., LTD.
    Inventors: Toru IWATA, Akira SUGAWA
  • Publication number: 20170015868
    Abstract: Embodiments of the invention provide a polishing composition including colloidal silica, pulverized wet-process silica particles, and a water-soluble polymer compound, wherein the water-soluble polymer compound is a polymer or copolymer having a constituent unit derived from an unsaturated aliphatic carboxylic acid. Various embodiments achieve a high polishing rate and obtain a good surface smoothness and end-face shape without the use of alumina particles.
    Type: Application
    Filed: September 28, 2016
    Publication date: January 19, 2017
    Applicant: YAMAGUCHI SEIKEN KOGYO CO., LTD.
    Inventors: Toru IWATA, Akira SUGAWA