Patents by Inventor Sang-Hak Hwang

Sang-Hak Hwang 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).

  • Aqueous size for fiber reinforced high temperature composites
    Patent number: 5430096
    Abstract: Stable aqueous size of ammonia-and/or amine-neutralized poly(amide-acid) of certain aromatic dianhydrides with certain aromatic diamines.
    Type: Grant
    Filed: April 28, 1994
    Date of Patent: July 4, 1995
    Assignee: E. I. Du Pont de Nemours and Company
    Inventors: Sang-Hak Hwang, Thomas J. Proffitt, Jr.
  • Nonwoven fabric for apparel insulating interliner
    Patent number: 4514455
    Abstract: A composite nonwoven fabric, particularly suited for an apparel insulating interliner, comprises a batt of crimped polyester staple fibers and a nonwoven sheet of continuous polyester filaments which are attached to each other by a series of parallel seams having a seam-to-seam spacing in the range of 1.7 to 5 cm. The batt is made of a particular blend of heavy and light staple fibers. The composite fabric has a density of 15 to 24 kg/m.sup.3 and an insulating value of at least 7 CLO/(kg/m.sup.2).
    Type: Grant
    Filed: July 26, 1984
    Date of Patent: April 30, 1985
    Assignee: E. I. Du Pont de Nemours and Company
    Inventor: Sang-Hak Hwang
  • Air lay-down process for producing uniform lightweight webs from textile fibers
    Patent number: 4089086
    Abstract: Process is disclosed which is suitable for high speed production of uniform, lightweight webs by air-laydown of textile fibers. A toothed disperser roll doffs the fibers into an air stream of high uniform velocity and low turbulence to form a thin fiber layer from which the fibers are deposited in web form on a moving screen. A curved disperser plate, shrouds a portion of the disperser roll up to the point of fiber doffing. By using a disperser plate with a rough surface, preferably one having lateral grooves, web uniformity is remarkably improved.
    Type: Grant
    Filed: December 1, 1975
    Date of Patent: May 16, 1978
    Assignee: E. I. Du Pont de Nemours and Company
    Inventors: Rashmikant Maganlal Contractor, Sang-Hak Hwang
  • Process for forming a staple fiber batt
    Patent number: 4043005
    Abstract: A staple fiber batt of improved uniformity is made by the fibers falling onto a moving conveyor, skimming off the top of the batt by jets of air flowing across the top of the batt, which thereby determines the level of the batt, and redepositing the skimmed off fibers onto said batt. The batt can then be compacted for further processing.
    Type: Grant
    Filed: June 22, 1976
    Date of Patent: August 23, 1977
    Assignee: E. I. Du Pont de Nemours & Company
    Inventors: Rashmikant Maganlal Contractor, Sang-Hak Hwang
  • Apparatus for forming a batt from staple fibers
    Patent number: 3981047
    Abstract: Apparatus for depositing staple fibers onto a conveyor belt to form a batt, including a chute feeder having an adjustable weir plate provided with a row of air jets along the bottom edge for maintaining a uniform fiber level at the exit from the chute. Fibers are supplied in an air stream from which they are separated by condenser means and fall into the chute over distributing baffles.
    Type: Grant
    Filed: May 13, 1975
    Date of Patent: September 21, 1976
    Assignee: E. I. Du Pont de Nemours and Company
    Inventors: Rashmikant M. Contractor, Sang-Hak Hwang
  • Air-laydown apparatus for forming uniform webs of staple fibers
    Patent number: 3932915
    Abstract: Process and apparatus are disclosed which are suitable for high speed production of uniform, lightweight webs by air-laydown of textile fibers. A toothed disperser roll doffs the fibers into an air stream of high uniform velocity and low turbulence to form a thin fiber stream from which the fibers are deposited in web form on a moving screen. A curved disperser plate, shrouds the disperser roll and prevents premature doffing. By using a disperser plate with a rough surface, preferably one having lateral grooves, web uniformity is remarkably improved.
    Type: Grant
    Filed: August 9, 1974
    Date of Patent: January 20, 1976
    Assignee: E. I. Du Pont de Nemours & Company
    Inventors: Rashmikant M. Contractor, Sang-Hak Hwang