Patents by Inventor Akimasa Aoyama

Akimasa Aoyama 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: 6288165
    Abstract: A process for producing vinyl acetate polymers comprises, after polymerization of at least one monomer comprising vinyl acetate, adding a conjugated polyene having a boiling point of at least 20° C. Saponified products of the vinyl acetate polymers obtained by this process can give molded articles causing little coloring and generation of gel-like agglomerates.
    Type: Grant
    Filed: December 5, 1997
    Date of Patent: September 11, 2001
    Assignee: Kuraray Co., Ltd.
    Inventors: Takeshi Moritani, Kaoru Ikeda, Akimasa Aoyama, Takaharu Kawahara, Yukihiro Ohara, Naoshi Nakagawa, Toshinori Tsugaru
  • Patent number: 5763101
    Abstract: A film having a dynamic modulus of elasticity at 75.degree. C. of 10.sup.8 to 10.sup.11 dyne/cm.sup.2 and an oxygen permeability at 20.degree. C., 75% RH of not more than 5.times.10.sup.12 cc.cm/cm.sup.2.sec.cmHg comprises a polyalcohol obtained by reducing a polyketone comprising a carbon monoxide-ethylene alternate copolymer, the polyalcohol having an intrinsic viscosity of 0.3 to 3.0 dl/g and a melting point of 110.degree. to 180.degree. C.; and a laminated film comprising the same. These films have excellent high-speed bag formability, heat-pack sealability, film formability, film appearance, adhesiveness and gas barrier properties.
    Type: Grant
    Filed: March 29, 1996
    Date of Patent: June 9, 1998
    Assignee: Kuraray Co., Ltd.
    Inventors: Kazuyori Yoshimi, Keizo Michihata, Akimasa Aoyama, deceased
  • Patent number: 5744547
    Abstract: A process for producing vinyl acetate polymers comprises, after polymerization of at least one monomer comprising vinyl acetate, adding a conjugated polyene having a boiling point of at least 20.degree. C. Saponified products of the vinyl acetate polymers obtained by this process can give molded articles causing little coloring and generation of gel-like agglomerates.
    Type: Grant
    Filed: June 25, 1996
    Date of Patent: April 28, 1998
    Assignee: Kuraray Co., Ltd.
    Inventors: Takeshi Moritani, Kaoru Ikeda, Akimasa Aoyama, deceased, Takaharu Kawahara, Yukihiro Ohara, Naoshi Nakagawa, Toshinori Tsugaru
  • Patent number: 5360670
    Abstract: This invention provides an ethylene-vinyl alcohol copolymer composition having specific flow characteristics in the relationship between the heating time and the extrusion rate measured with a capillary rheometer (Koka Flow Tester), and a multilayered structure utilizing the same.From the EVOH composition according to the present invention, can be obtained a molded article, particularly a multilayered structure, having an excellent appearance; more particularly, in a continuous melt molding operation over a long period, a molded article, particularly a multilayered structure, having an excellent appearance can always be obtained without worsening the appearance with running time.
    Type: Grant
    Filed: November 20, 1992
    Date of Patent: November 1, 1994
    Assignee: Kuraray Co., Ltd.
    Inventors: Kiyoshi Yonezu, Akimasa Aoyama, Takuji Okaya, Satoshi Hirofuji, Yukio Ozeki
  • Patent number: 5352750
    Abstract: Process for producing ethylene-vinyl ester copolymers using a polymerization solvent of a dialkyl sulfoxide (process X); process for producing ethylene-vinyl alcohol copolymer by liquid phase saponification using a solvent of a dialkyl sulfoxide (process Y); and process for producing shaped articles which comprises contacting the ethylene-vinyl alcohol copolymer obtained by the process Y, or that obtained by saponifying the ethylene-vinyl ester copolymer obtained by process X, to a non-solvent for ethylene-vinyl alcohol copolymer.Ethylene-vinyl ester copolymers having a wide range of ethylene content and higher degree of polymerization than that with solution polymerization using methanol.The rate of saponification is higher than that with single solvent system of lower alcohol.Production cost is low, because production process of polymer is directly connected to that of shaped articles utilizing the polymer.
    Type: Grant
    Filed: May 27, 1993
    Date of Patent: October 4, 1994
    Assignee: Kuraray Co., Ltd.
    Inventors: Hisamichi Yanai, Takanori Kitamura, Fumio Nakahara, Katsumi Shimizu, Akimasa Aoyama, Takeshi Moritani
  • Patent number: 5342662
    Abstract: Provided are compositions comprising a saponified product of an ethylene-vinyl acetate copolymer having an ethylene content of 20 to 80 mol % and a saponification degree of vinyl acetate component of at least 95 mol %, said composition containing 20 to 200 ppm as converted to alkali metal of an alkali metal acetate, 30 to 250 ppm of acetic acid, and 5 to 500 ppm as converted to phosphate ion of phosphoric acid or an alkali metal hydrogenphosphate, and having a content ratio of acetic acid/alkali metal acetate of 0.1 to 1 and the flow characteristic that the extrusion rate does not substantially increase for at least 10 hours in the relationship between the heating time and the extrusion rate with a capillary rheometer (Koka Flow Tester) at at least one temperature 10.degree. to 80.degree. C. above the melting point.
    Type: Grant
    Filed: November 16, 1992
    Date of Patent: August 30, 1994
    Assignee: Kuraray Co., Ltd.
    Inventors: Akimasa Aoyama, Tetsuya Katayama, Takeshi Moritani, Junnosuke Yamauchi, Satoshi Hirofuji
  • Patent number: 5302417
    Abstract: An aqueous dispersion comprising a dispersoid of an ethylene-vinyl alcohol copolymer having an ethylene content of 15 to 65 mole % and a dispersion stabilizer of a saponified product of an ethylene-vinyl ester copolymer having an ionic group and having an ethylene content of 10 to 70 mole % and a saponification degree of at least 80%. According to the present invention, aqueous dispersions with high solid concentration and having excellent stability during storage or upon use. The film obtained by applying and then drying the aqueous dispersion has excellent gas barrier properties.
    Type: Grant
    Filed: August 9, 1993
    Date of Patent: April 12, 1994
    Assignee: Kurarav Co., Ltd.
    Inventors: Junnosuke Yamauchi, Akimasa Aoyama, Toshio Tsuboi, Satoshi Hirofuji, Takeshi Moritani
  • Patent number: 5272200
    Abstract: An aqueous dispersion comprising a dispersoid of an ethylene-vinyl alcohol copolymer having an ethylene content of 15 to 65 mole % and a dispersion stabilizer of a saponified product of an ethylene-vinyl ester copolymer having an ionic group and having an ethylene content of 10 to 70 mole % and a saponification degree of at least 80%. According to the present invention, aqueous dispersions with high solid concentration and having excellent stability during storage or upon use. The film obtained by applying and then drying the aqueous dispersion has excellent gas barrier properties.
    Type: Grant
    Filed: October 14, 1992
    Date of Patent: December 21, 1993
    Assignee: Kuraray Co., Ltd.
    Inventors: Junnosuke Yamauchi, Akimasa Aoyama, Toshio Tsuboi, Satoshi Hirofuji, Takeshi Moritani
  • Patent number: 5240997
    Abstract: Process for producing ethylene-vinyl ester copolymers using a polymerization solvent of a dialkyl sulfoxide (process X); process for producing ethylene-vinyl alcohol copolymer by liquid phase saponification using a solvent of a dialkyl sulfoxide (process Y); and process for producing shaped articles which comprises contacting the ethylene-vinyl alcohol copolymer obtained by the process Y, or that obtained by saponifying the ethylene-vinyl ester copolymer obtained by process X, to a non-solvent for ethylene-vinyl alcohol copolymer.Ethylene-vinyl ester copolymers having a wide range of ethylene content and higher degree of polymerization than that with solution polymerization using methanol.The rate of saponification is higher than that with single solvent system of lower alcohol.Production cost is low, because production process of polymer is directly connected to that of shaped articles utilizing the polymer.
    Type: Grant
    Filed: January 8, 1992
    Date of Patent: August 31, 1993
    Assignee: Kuraray Co., Ltd.
    Inventors: Hisamichi Yanai, Takanori Kitamura, Fumio Nakahara, Katsumi Shimizu, Akimasa Aoyama, Takeshi Moritani
  • Patent number: 5221566
    Abstract: A multilayered container comprising an intermediate layer of a resin composition (A) which comprises 50-95% by weight of a specific EVOH, and 50-5% by weight of an inorganic filler, and inner and outer layers of a moisture resistant thermoplastic resin (B), at least the body wall part of the container comprising multiplicity of regions in which substantially 2-dimensional thin layers of the inorganic filler extend parallel with the wall surface and laminated with each other, said layer of said resin composition (A) having a specific moisture permeability.The multilayered container can readily be prepared by thermoforming from the corresponding multilayered structure.
    Type: Grant
    Filed: March 19, 1992
    Date of Patent: June 22, 1993
    Assignee: Kuraray Co., Ltd.
    Inventors: Makio Tokoh, Akimasa Aoyama, Toshiaki Sato, Taichi Negi, Hidemasa Oda, Satoshi Hirofuji
  • Patent number: 5194474
    Abstract: Provided are compositions comprising a saponified product of an ethylene-vinyl acetate copolymer having an ethylene content of 20 to 80 mol % and a saponification degree of vinyl acetate component of at least 95 mol %, said composition containing 20 to 200 ppm as converted to alkali metal of an alkali metal acetate, 30 to 250 ppm of acetic acid, and 5 to 500 ppm as converted to phosphate ion of phosphoric acid or an alkali metal hydrogenphosphate, and having a content ratio of acetic acid/alkali metal acetate of 0.1 to 1 and the flow characteristic that the extrusion rate does not substantially increase for at least 10 hours in the relationship between the heating time and the extrusion rate with a capillary rheometer (Koka Flow Tester) at at least one temperature 10.degree. to 80.degree. C. above the melting point.
    Type: Grant
    Filed: February 27, 1990
    Date of Patent: March 16, 1993
    Assignee: Kuraray Co., Ltd.
    Inventors: Akimasa Aoyama, Tetsuya Katayama, Takeshi Moritani, Junnosuke Yamauchi, Satoshi Hirofuji
  • Patent number: 5134036
    Abstract: Ethylene-vinyl alcohol copolymers wherein ethylene content is 10-70 mol % diad syndiotacticity is not less than 55 mol %, and intrinsic viscosity [.eta.] is not less than 0.05 l/g when measured with a mixed solvent of 85 weight % of phenol and 15 weight % of water at 30 20 C., which show less decrease of resistance to gas permeation under high temperature and high humidity, while retaining resistance to get permeation under low humidity, transparency and melt moldability, and moldings and laminates formed thereof.
    Type: Grant
    Filed: May 9, 1991
    Date of Patent: July 28, 1992
    Assignee: Kuraray Co., Ltd.
    Inventors: Junichi Uemura, Akimasa Aoyama, Hitoshi Maruyama, Toshiaki Sato, Takuji Okaya
  • Patent number: 5118743
    Abstract: This invention provides an ethylene-vinyl alcohol copolymer composition having specific flow characteristics in the relationship between the heating time and the extrusion rate measured with a capillary rheometer (Koka Flow Tester), and a multilayered structure utilizing the same.From the EVOH composition according to the present invention, can be obtained a molded article, particularly a multilayered structure, having an excellent appearance; more particularly, in a continuous melt molding operation over a long period, a molded article, particularly a multilayered structure, having an excellent appearance can always be obtained without worsening the appearance with running time.
    Type: Grant
    Filed: August 31, 1988
    Date of Patent: June 2, 1992
    Assignee: Kuraray Co., Ltd.
    Inventors: Kiyoshi Yonezu, Akimasa Aoyama, Takuji Okaya, Satoshi Hirofuji, Yukio Ozeki
  • Patent number: 4824904
    Abstract: The present invention relates to resin compositions and laminates using saponified ethylene-vinyl acetate copolymers containing a polyether component. Formed products and laminates obtained from the resin compositions are flexible, excellent in flexural fatigue resistance and gas barrier properties and extremely useful as flexible laminates.
    Type: Grant
    Filed: March 19, 1987
    Date of Patent: April 25, 1989
    Assignee: Kuraray Co., Ltd.
    Inventors: Akimasa Aoyama, Takeshi Moritani, Kiyoshi Yonezu, Takuji Okaya
  • Patent number: 4713296
    Abstract: There is provided a laminate having good gas barrier properties which comprises at least one barrier layer of modified ethylene-vinyl alcohol copolymer containing 0.1 to 5 mol % of pyrrolidone ring-containing units and 20 to 55 mol % of ethylene units, with the degree of saponification of the vinyl acetate component being at least 98 mol %, and at least one layer of thermoplastic resin. This laminate is superior in drawability, and can be made by drawing into bottles, cups, and the like which exhibit excellent clarity, appearance, and gas barrier properties.
    Type: Grant
    Filed: June 12, 1986
    Date of Patent: December 15, 1987
    Assignee: Kuraray Co., Ltd.
    Inventors: Akimasa Aoyama, Takeshi Moritani, Kiyoshi Yonezu, Taichi Negi, Takuji Okaya
  • Patent number: 4636551
    Abstract: There is provided a coating material made of a saponification product of a modified ethylene-vinyl acetate copolymer containing a cross-linkable olefinically unsaturated monomer. The saponification product is characterized by its intrinsic viscosity not greater than 0.7 dl/g which is measured at 20.degree. C. using phenol containing 15 wt % of water as a solvent. This polymer is readily soluble in solvents, and the resulting solution can have concentration as high as 20 to 50 wt % and provide coating film which is as strong as that obtained from the conventional EVOH having a high degree of polymerization.
    Type: Grant
    Filed: May 29, 1985
    Date of Patent: January 13, 1987
    Assignee: Kuraray Co, Ltd.
    Inventors: Takuji Okaya, Yoshinari Tanaka, Kiyoshi Yonezu, Akimasa Aoyama, Takeshi Moritani
  • Patent number: 4576988
    Abstract: A melt molding material which comprises a saponified product of a silicon-containing ethylene-vinyl acetate copolymer. When this melt molding material is formed into a sheet, said sheet is excellent in extensibility and thus suitable for deep forming. The decrease in gas barrier properties is small even under high moisture conditions, and its stress cracking resistance is excellent.
    Type: Grant
    Filed: December 3, 1984
    Date of Patent: March 18, 1986
    Assignee: Kuraray Co., Ltd.
    Inventors: Yoshinari Tanaka, Akimasa Aoyama, Takeshi Moritani, Kenji Satoh, Takuji Okaya