Patents by Inventor Ervin Townsend Powers, Jr.

Ervin Townsend Powers, Jr. 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).

  • Process for improving electrostatic charging of plexifilaments
    Patent number: 6455619
    Abstract: The efficiency of electrostatic charging of polyolefin web in a process for flash-spinning polyolefin plexifilament from solution in a C4-C7 hydrocarbon, forming the plexifilament into a web, electrostatically charging the web, and laying the web down as a sheet is improved by having present in the electrostatic charging step environment a charge-improving compound, which can be any one of a number of specifically identified classes of charge-improving compounds. The charge improving compounds are present in an amount of at least 0.1 ppm of the atmosphere in that environment or more.
    Type: Grant
    Filed: October 31, 1995
    Date of Patent: September 24, 2002
    Assignee: E. I. duPont de Nemours and Company
    Inventors: David Jackson McGinty, Ervin Townsend Powers, Jr., Hyunkook Shin, Roger Keith Siemionko, David Martin Taylor
  • Wand purging for electrostatic charging system in flash spinning apparatus
    Patent number: 5750152
    Abstract: This invention relates to a method and apparatus for sweeping dust and debris from the needles of a wand which is for applying an electrostatic charge to a plexifilamentary film-fibril web. The needles of the wand tend to acquire dust and debris from the polymer and by the present invention the dust and debris are efficiently swept away by a gaseous fluid flow over the needles preferably so that the fluid passes circumferentially over the needles through an annular passage.
    Type: Grant
    Filed: April 19, 1996
    Date of Patent: May 12, 1998
    Assignee: E. I. du Pont de Nemours and Company
    Inventors: Ervin Townsend Powers, Jr., Edgar North Rudisill
  • Flash-spinning process
    Patent number: 5707580
    Abstract: An improved apparatus and process for flash-spinning plexifilamentary film-fibrils are provided in which a static mixing device is provided in the conduit through which the polymer and spin agent are provided to the spin orifice of the flash spinning apparatus. Preferably, the flash-spinning apparatus includes a chamber immediately upstream of the spinning orifice and the static mixing device is disposed within the chamber. Plexifilamentary webs produced according to the invention have been found to have more densely spaced film-fibrils, more tie points and fewer holes. Bonded plexifilamentary sheets made from such webs have a more uniform thickness and a slightly higher tensile strength than sheets produced without the use of static mixers.
    Type: Grant
    Filed: May 1, 1996
    Date of Patent: January 13, 1998
    Assignee: E. I. du Pont de Nemours and Company
    Inventors: Daniel Scott Colley, Ervin Townsend Powers, Jr.
  • Process for improving electrostatic charging of plexifilaments
    Patent number: 5643525
    Abstract: The efficiency of electrostatic charging of polyolefin web in a process for flash-spinning polyolefin plexifilament from solution in a C.sub.4 -C.sub.7 hydrocarbon, forming the plexifilament into a web, electrostatically charging the web, and laying the web down as a sheet is improved by having present in the electrostatic charging step environment a charge-improving compound, which can be any one of a number of specifically identified classes of charge-improving compounds. The charge improving compounds are present in an amount of at least 0.1 ppm of the atmosphere in that environment or more.
    Type: Grant
    Filed: March 25, 1994
    Date of Patent: July 1, 1997
    Assignee: E. I. Du Pont de Nemours and Company
    Inventors: David Jackson McGinty, Ervin Townsend Powers, Jr., Hyunkook Shin, Roger Keith Siemionko, David Martin Taylor