Patents Assigned to Diafoil Company Limited
  • Patent number: 5581435
    Abstract: A film capacitor element produced from a metallized polyester film is described. In the metallized polyester film, the adhesion between a vapor-deposited metal layer and a polyester substrate is improved by providing a coating layer comprising a specific water soluble or water dispersible resin. The film capacitor produced by the use of the metallized polyester film has good moist heat resistance and long term stability in performance.
    Type: Grant
    Filed: November 8, 1991
    Date of Patent: December 3, 1996
    Assignee: Diafoil Company, Limited
    Inventors: Shin-ichi Kinoshita, Naohiro Takeda
  • Patent number: 5385768
    Abstract: There is disclosed an electrically conductive polyester film comprising a polyester base film and a coating layer which is formed by applying a coating liquid to said base film, thereafter stretching the coated film and heat-setting the film, wherein said coating liquid is an aqueous composition and contains carbon black in an amount of 30-60% by weight of the solid content and produces a layer when dried at 80.degree. C. for 10 minutes, the rupture elongation of said layer being at least 300% and is heat-settable at 10.degree.-200.degree. C., and said coating layer having a surface resistivity of 10.sup.4 -10.sup.10 .OMEGA./.quadrature. and a surface roughness of not more than 0.05 .mu.m. This polyester film exhibits good electric resistivity and light-shielding proper.
    Type: Grant
    Filed: April 28, 1993
    Date of Patent: January 31, 1995
    Assignee: Diafoil Company, Limited
    Inventors: Yuzo Otani, Naohiro Takeda
  • Patent number: 5188891
    Abstract: Disclosed herein is a magnetic recording medium comprising a polyester film layer, a coating type magnetic layer provided on one side of said polyester film layer, and a back-coat layer provided on the other side of said polyester film layer.
    Type: Grant
    Filed: June 25, 1991
    Date of Patent: February 23, 1993
    Assignee: Diafoil Company, Limited
    Inventors: Naohiro Takeda, Yuzo Otani, Nariaki Okajima, Yoshihiko Ito, Shin-ichi Kinoshita, Masashi Inagaki, Takashi Harada
  • Patent number: 5153302
    Abstract: A biaxially oriented polyester film for use in a capacitor having improved break down strength, which polyester having an acid component at least 90% by mole of which is terephthalic acid and a glycol component at least 97% by mole of which is 1,4-cyclohexanedimenthanol, in which film, an extracted amount with chloroform is not more than 1.3% by weight per 24 hours.
    Type: Grant
    Filed: October 25, 1991
    Date of Patent: October 6, 1992
    Assignee: Diafoil Company, Limited
    Inventors: Narihiro Masuda, Syuji Anno
  • Patent number: 5106681
    Abstract: Disclosed herein is a polyester film containing specific fine spherical silica particles. The film of the present invention is especially suitable as a base film for a magnetic recording medium or dielectric for a capacitor. The films of the present invention have the markedly improved properties such as surface properties, electromagnetic properties, electrical properties, etc. due to the excellent dispersibility of the particles in the film.
    Type: Grant
    Filed: October 12, 1989
    Date of Patent: April 21, 1992
    Assignee: Diafoil Company, Limited
    Inventors: Kazuo Endo, Nobuyasu Shudo, Chikakazu Kawaguchi, Yoshio Meguro, Masahiko Fujimoto, Toshifumi Takisawa, Masashi Inagaki
  • Patent number: 5100719
    Abstract: A biaxially oriented polyester film containing 0.01 to 4 wt % of multilayered high-molecular particles having a weight-average particle size of 0.05 to 3 .mu.m which comprise core crosslinked high-molecular particles having a glass transition temperature of not lower than 100.degree. C. coated with a crosslinked polymer having a glass transition temperature of lower than 100.degree. C., the ratio Dw/Dn of the weight-average particle size (Dw) and the number-average particle size (Dn) being not more than 1.3 is disclosed. The film of the present invention has excellent running property and wear resistance and is useful as a base film for various products such as magnetic recording media, capacitors, photomechanical plates, electric insulators, heat-sensitive transfer film, packaging film, transfer marks and gold and silver threads. Thus, the present invention has a high industrial value.
    Type: Grant
    Filed: December 7, 1990
    Date of Patent: March 31, 1992
    Assignee: Diafoil Company, Limited
    Inventors: Kazuo Endo, Megumi Komiyama
  • Patent number: 5096773
    Abstract: A biaxially oriented polyester film containing 0.05 to 3 wt % of agglomerates of primary particles of aluminum oxide having an average particle size of 5 to 40 nm, the agglomerates having an average particle size of 50 to 400 nm. The film of the present invention is excellent in the wear resistance against various members such as a metal pin, and suitable for various industrial purposes including a base film of a magnetic recording medium.
    Type: Grant
    Filed: June 1, 1990
    Date of Patent: March 17, 1992
    Assignee: Diafoil Company, Limited
    Inventor: Seiji Sakamoto
  • Patent number: 5095332
    Abstract: A data processing apparatus provided in a copying machine is provided for eliminating the need for replacing the data such as adjusting values in case of replacing a memory board in the copying machine. The data processing apparatus provided in a copying machine which is used when a first memory for storing electrical signals indicative of adjusting values needed in operation of the copying machine is replaced by a second memory, the data processing apparatus includes means for printing-out on a sheet image informations representative of the adjusting values stored in the first memory, means for reading the image informations on the sheet, and means for converting the read image informations to electrical signals indicative of adjusting values and for storing the converted electrical signals in the second memory.
    Type: Grant
    Filed: February 25, 1991
    Date of Patent: March 10, 1992
    Assignee: Diafoil Company, Limited
    Inventors: Kazuyuki Ohnishi, Kiyoshi Inamoto, Masato Tokishige, Takeshi Takarada
  • Patent number: 5087526
    Abstract: The present invention provide a biaxially oriented polyester film for use in a floppy disc, which has a coefficient of thermal expansion (.alpha..sub.T) in film plane of (1.0.+-.0.5).times.10.sup.-5 mm/mm/.degree.C. and a heat shrinkage of not higher than 0.09% after treatment the film for 72 hours under conditions of a temperature of 60.degree. C. and a humidity of 80% RH in any directions in film plane, and simultaneously satisfies the following equations (1) to (5):1.490.ltoreq.n.sub..alpha. .ltoreq.1.500 (1)0.155.ltoreq..DELTA.P.ltoreq.0.168 (2)1.600.ltoreq.n.ltoreq.1.603 (3)40.ltoreq.X.sub.100 .ltoreq.60 (4)1.385.ltoreq..rho..ltoreq.1.400 (5)wherein n.sub..alpha. represents a refractive index in film thickness direction, .DELTA.P represents a degree of planar orientation, n represents an average refractive index, X.sub.100 represents a crystal size (.ANG.) of (110) face, and .rho. represents a density (g/cm.sup.3).
    Type: Grant
    Filed: October 18, 1990
    Date of Patent: February 11, 1992
    Assignee: Diafoil Company, Limited
    Inventors: Kichinojo Tomitaka, Masumi Koizumi
  • Patent number: 5082730
    Abstract: Disclosed herein are a stretched antistatic laminate film comprising at least one coating layer containing a polymer having pyrrolidium rings in the main molecular chain, and a polyester film layer, a magnetic recording medium using the same, and a recording material for heat sensitive transfer printing using the same.
    Type: Grant
    Filed: December 2, 1988
    Date of Patent: January 21, 1992
    Assignee: Diafoil Company, Limited
    Inventors: Naohiro Takeda, Yuzo Otani, Nariaki Okajima, Masahiro Kita
  • Patent number: 5071690
    Abstract: Disclosed herein is a moldable biaxially stretched polyester film having a tensile strength at 100% elongation (F.sub.100), measured in an atmosphere of 150.degree. C., of 0.5 to 7 kg/mm.sup.2.The biaxially stretched polyester film according to the present invention is excellent in moldability.
    Type: Grant
    Filed: January 30, 1990
    Date of Patent: December 10, 1991
    Assignee: Diafoil Company, Limited
    Inventors: Yujiro Fukuda, Tomoyuki Kotani
  • Patent number: 5061571
    Abstract: A biaxially oriented polyester film containing 0.01 to 4 wt %, based on the polyester film, of inorganic particles, the volumetric shape parameter being 0.02 to 0.2, the weight-average particle size being 0.05 to 3 .mu.m, and the ratio (Dw/Dn) of the weight-average particle size (Dw) and the number-average particle size (Dn) being not more than 1.1 is disclosed. The film of the present invention has a uniform surface and shows excellent running property and wear resistance so that it is useful as a base film for a magnetic tape, for example. Thus, the film of the present invention has a high industrial value.
    Type: Grant
    Filed: December 7, 1990
    Date of Patent: October 29, 1991
    Assignee: Diafoil Company, Limited
    Inventor: Seiji Sakamoto
  • Patent number: 5045379
    Abstract: A polyester film suitable for a base of high density magnetic recording medium containing barium ferrite as a magnetic material characterized in that the centerline average roughness (Ra) is not more than 0.025 .mu.m and the F.sub.5 value in the longitudinal direction is not less than 14 kg/mm.sup.2 is disclosed wherein the polyester film exhibit excellent better durability when used with barium ferrite as a magnetic material.
    Type: Grant
    Filed: June 2, 1989
    Date of Patent: September 3, 1991
    Assignee: Diafoil Company, Limited
    Inventors: Tomoyuki Kotani, Shigeo Utsumi, Kichinojo Tomitaka
  • Patent number: 5045384
    Abstract: A polyester laminated film comprising a polyester inner layer having a density greater than 1.3 g/cm.sup.3 and polyester outer layers on both sides of said inner layer having a density in the range of 0.4 to 1.3 g/cm.sup.3 is disclosed. The laminated film of this invention has high discrimination property and is also improved in image printability on the film surface in comparison with the conventional polyester films. When, for instance, the present laminated film is used as base for prepaid cards, which is a preferred application of the present film, it contributes to the enhancement of security of the cards, and it also enables high-quality printing by thermal transfer method.
    Type: Grant
    Filed: March 9, 1990
    Date of Patent: September 3, 1991
    Assignee: Diafoil Company, Limited
    Inventor: Satoshi Otonari
  • Patent number: 5023291
    Abstract: Disclosed herein is a polyester composition which comprises a polyester with a terminal carboxyl group content of 40 to 80 equivalents/10.sup.6 and 0.0 to 5 wt %, based on the total amount of the polyester composition, aluminum oxide particles of 0.005 to 5 .mu.m in average particle diameter and which has a melt resistivity of 6 x 10.sup.6 to 5 x 10.sup.8 .OMEGA..cm.By using the polyester composition, it is possible to successively produce a film having excellent wear resistance and flatness over a long production run.
    Type: Grant
    Filed: July 13, 1989
    Date of Patent: June 11, 1991
    Assignee: Diafoil Company, Limited
    Inventors: Seiji Sakamoto, Nobuyasu Shudo
  • Patent number: 5006589
    Abstract: Disclosed in this invention is a polyester film for magnetic recording media, containing 0.05 to 5% by weight of inactive inorganic particles (A) having a Mohs hardness of 6 or above and an average particle size of 0.005 to 1.0 .mu.m and 0.01 to 2.0% by weight of inactive particles (B) having an average particle size which is greater than that of the particles (A) and in the range of 0.1 to 3.0 .mu.m, the polyester film having an intrinsic viscosity in the range of 0.52 to 0.65. The polyester film of this invention is excellent in abrasion resistance, scuff resistance and slitting qualities and useful as a base film for magnetic recording media.
    Type: Grant
    Filed: June 2, 1989
    Date of Patent: April 9, 1991
    Assignee: Diafoil Company, Limited
    Inventors: Seiji Sakamoto, Chikakazu Kawaguchi, Yoshio Meguro, Takashi Harada, Toshifumi Takisawa
  • Patent number: 4990400
    Abstract: Disclosed herein is a polyester film containing specific fine spherical silica particles. The film of the present invention is especially suitable as a base film for a magnetic recording medium or dielectric for a capacitor. The films of the present invention have the markedly improved properties such as surface properties, electromagnetic properties, electrical properties, etc. due to the excellent dispersibliity of the particles in the film.
    Type: Grant
    Filed: October 12, 1989
    Date of Patent: February 5, 1991
    Assignee: Diafoil Company, Limited
    Inventors: Kazuo Endo, Nobuyasu Shudo, Chikakazu Kawaguchi, Yoshio Meguro, Masahiko Fujimoto, Toshifumi Takisawa, Masashi Inagaki, Kenji Kato, Shigeo Utsumi, Kichinojo Tomitaka, Shigeyuki Watanabe, Kazuyuki Akatsu
  • Patent number: 4986746
    Abstract: A process for preparing polymer film includes the step of extruding a molten thermoplastic polymer through a die provided with neck-down prevention pieces onto a rotating cooling drum, and cooling the polymer to solidify, wherein the neck-down prevention pieces are made of aluminum or alumina and provided with a cooling device.
    Type: Grant
    Filed: August 8, 1989
    Date of Patent: January 22, 1991
    Assignee: Diafoil Company, Limited
    Inventor: Mitsugu Hosoi
  • Patent number: 4985537
    Abstract: A biaxially stretched polyester film which satisfies the following equations (1) to (4):0.155 . .ltoreq..DELTA.P .ltoreq.0.180 (1)1.6050 ..ltoreq.n..ltoreq.1.6085 (2)n .gtoreq.1.622-(0.1.times..DELTA.P) (3).sup..alpha. MD+TD ..ltoreq.3.0 (4)wherein .DELTA.P, n and .sup..alpha. MD+TD respectively respect the degree of surface orientation, the average refractive index and the sum (%) of the shrinkage in the machine and transverse directions after the film is subjected to heat treatment at 105.degree. C. for 30 minutes. The film is not easily curled even if one side thereof is treated with a solvent, and is thus suitable for use involving a step of dipping one surface of a film in a solvent, such as solvent development-type photo resist film and base films for magnetic recording media.
    Type: Grant
    Filed: April 13, 1989
    Date of Patent: January 15, 1991
    Assignee: Diafoil Company, Limited
    Inventors: Shigeo Utsumi, Tomoyuki Kotani, Kichinojo Tomitaka
  • Patent number: 4985538
    Abstract: A shrinkable polyester film having a sufficient shrinkage, a sufficient resistance to solvent for printing ink, a shrinking property not to cause wrinkles, a warm water resistance sufficient for preventing wrinkles, slack and whitening is disclosed herein.The shrinkable polyester film of the present invention may be used as labels for various vessels such as glass bottle, heat-resistant PET bottle and non heat-resistant PET bottle.
    Type: Grant
    Filed: November 12, 1987
    Date of Patent: January 15, 1991
    Assignee: Diafoil Company, Limited
    Inventors: Yujiro Fukuda, Shigeo Utsumi