Patents by Inventor Dusan C. Prevorsek

Dusan C. Prevorsek 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: 4970276
    Abstract: Phenolic cyanate/phenolic triazine copolymers and cured resins prepared therefrom.
    Type: Grant
    Filed: May 26, 1989
    Date of Patent: November 13, 1990
    Assignee: Allied-Signal Inc.
    Inventors: Sajal Das, Dusan C. Prevorsek
  • Patent number: 4920159
    Abstract: The present invention is a composition comprising a friction resistant filler and a cyanato group containing phenolic resin which has repeating units of the formula: ##STR1## wherein p is 0 or an integer of one or more, q is an integer of one or more, and X is a radical selected from the group consisting of: --CH.sub.2 --, --CO--, --SO.sub.2 --, ##STR2## with --CH.sub.2 -- preferred. R is the same or different and is selected from the group consisting of hydrogen and methyl radicals and composition based on phenolic triazine resins derived therefrom.
    Type: Grant
    Filed: January 11, 1989
    Date of Patent: April 24, 1990
    Assignee: Allies-Signal Inc.
    Inventors: Sajal Das, Dusan C. Prevorsek, Seong K. Rhee, William J. Bulger
  • Patent number: 4916000
    Abstract: The present invention provides an improved composite which comprises one or more layers, at least one of said layers comprising network of high strength filaments having a tensile modulus of at least about 160 grams/denier, a tenacity of at least about 7 g/denier and an energy-to-break of at least about 8 joules/gram in a matrix material, the ratio of the thickness of said layer to the equivalent diameter of said filaments is equal to or less than about 12.8, and complex composite articles formed from said composite.
    Type: Grant
    Filed: July 13, 1987
    Date of Patent: April 10, 1990
    Assignee: Allied-Signal Inc.
    Inventors: Hsin L. Li, Dusan C. Prevorsek, Gary A. Harpell, Young D. Kwon
  • Patent number: 4897902
    Abstract: Ultrahigh molecular weight polyethylene fibers of high tenacity and modulus shrink controlled amounts at temperatures in the range of 100.degree.-155.degree. C. Fabrics and twisted multifilament yarns of these fibers are heat-shrunk or heat-set at these temperatures.
    Type: Grant
    Filed: November 4, 1988
    Date of Patent: February 6, 1990
    Assignee: Allied-Signal Inc.
    Inventors: Sheldon Kavesh, Dusan C. Prevorsek, Gary A. Harpell
  • Patent number: 4883628
    Abstract: Polyacrylonitrile (PAN) fibers are prepared by forming a 2-15 weight % solution of PAN of M.sub.w at least 500,000, extruding, cooling to below the gel temperature, extracting and drying. At least one of the gel fiber, the fiber containing extraction solvent and the dried gel is stretched. The product PAN fibers have a M.sub.w at least 500,000 (e.g. 1,000,000-4,000,000 or 1,500,000-2,500,000), a tenacity at least 5 g/den (e.g., at least 7 g/den) and a secant modulus at least 100 g/den (e.g. at least 125 g/den).
    Type: Grant
    Filed: September 18, 1986
    Date of Patent: November 28, 1989
    Assignee: Allied-Signal Inc.
    Inventors: Young D. Kwon, Sheldon Kavesh, Dusan C. Prevorsek
  • Patent number: 4876774
    Abstract: Ultrahigh molecular weight polyethylene fibers of high tenacity and modulus shrink controlled amounts at temperatures in the range of 100.degree.-145.degree. C. Fabrics and twisted multifilament yarns of these fibers are heat-shrunk or heat-set at these temperatures.
    Type: Grant
    Filed: September 1, 1983
    Date of Patent: October 31, 1989
    Assignee: Allied-Signal Inc.
    Inventors: Sheldon Kavesh, Dusan C. Prevorsek, Gary A. Harpell
  • Patent number: 4851279
    Abstract: The present invention is a fiber comprising cyanato group containing phenolic resin comprising repeating units of the formula: ##STR1## wherein p is 0 or an integer of one or more, q is 0 or an integer of 1 or more, X is a radical selected from the group consisting of: --CH.sub.2 --, --CO--, --SO.sub.2 --, ##STR2## and R is the same or different and is selected from the group consisting of hydrogen and methyl radicals. The fiber of the present invention can be made a phenolic triazine derived from the cyanato group containing phenolic resin.
    Type: Grant
    Filed: December 21, 1987
    Date of Patent: July 25, 1989
    Assignee: Allied-Signal Inc.
    Inventors: Sajal Das, Dusan C. Prevorsek
  • Patent number: 4845162
    Abstract: The present invention relates to a composition comprising a phenolic resin, as for example phenol formaldehyde, an active hydrogen containing polymer as for example a polyamide, and a curing agent, such as a polyepoxide.
    Type: Grant
    Filed: June 1, 1987
    Date of Patent: July 4, 1989
    Assignee: Allied-Signal Inc.
    Inventors: George J. Schmitt, Dusan C. Prevorsek, Hong B. Chin, Kwok W. Lem
  • Patent number: 4831086
    Abstract: The present invention is a cyanato group containing phenolic resin of the formula: ##STR1## wherein n is 0 or an integer of one or more, and R is the same or different and is selected from the group consisting of hydrogen and methyl radicals. The advancement over the art is that the resin of the present invention is stable and has a long shelf life. This is indicated by the gel time of greater than 1 minute, preferably greater than 2 minutes, more preferably greater than 10 minutes, and most preferably greater than 20 minutes at 155.degree. C. Alternately, the improved phenolic triazine resin of the present invention can be characterized as having a thermal stability indicated by thermal decomposition temperature of at least 400.degree. C. and preferably of at least 450.degree. C. as measured by Thermal Gravimetric Analysis (TGA).
    Type: Grant
    Filed: October 5, 1987
    Date of Patent: May 16, 1989
    Assignee: Allied-Signal Inc.
    Inventors: Sajal Das, Dusan C. Prevorsek
  • Patent number: 4819458
    Abstract: Ultrahigh molecular weight polyethylene fibers of high tenacity and modulus shrink controlled amounts at temperatures in the range of 100.degree.-145.degree. C. Fabrics and twisted multifilament yarns of these fibers are heat-shrunk or heat-set at these temperatures.
    Type: Grant
    Filed: September 30, 1982
    Date of Patent: April 11, 1989
    Assignee: Allied-Signal Inc.
    Inventors: Sheldon Kavesh, Dusan C. Prevorsek, Gary A. Harpell
  • Patent number: 4771113
    Abstract: Modified phenolic resins and cured resins prepared therefrom.
    Type: Grant
    Filed: June 15, 1987
    Date of Patent: September 13, 1988
    Assignee: Allied Corporation
    Inventors: Sajal Das, Dusan C. Prevorsek
  • Patent number: 4757118
    Abstract: Modified phenolic resins and cured resins prepared therefrom.
    Type: Grant
    Filed: January 23, 1986
    Date of Patent: July 12, 1988
    Assignee: Allied Corporation
    Inventors: Sajal Das, Dusan C. Prevorsek
  • Patent number: 4748064
    Abstract: The present invention provides an improved, composite article of manufacture which comprises a network of fibers having a tensile modulus of at least about 500 grams/denier and an energy-to-break of at least about 22 Joules/gram. An elastomeric matrix material having a tensile modulus of less than about 6,000 psi, measured at 25.degree. C.
    Type: Grant
    Filed: December 9, 1985
    Date of Patent: May 31, 1988
    Assignee: Allied Corporation
    Inventors: Gary A. Harpell, Igor Palley, Sheldon Kavesh, Dusan C. Prevorsek
  • Patent number: 4737401
    Abstract: The present invention provides an improved article of manufacture which comprises at least one network of high strength, extended chain fiber or yarn selected from the group consisting of extended chain polyethylene (ECPE) extended chain polypropylene (ECPP) fibers, extended chain polyvinyl alcohol (PVA) fiber and extended chain polyacrylonitrile (PAN) fiber. The fibers and yarn have a denier of not more than about 500 and a tensile modulus of at least about 200 g/denier. The fibers and yarn preferably have a tensile modulus of at least about 500 grams/denier and an energy-to-break of at least about 22 Joules/gram. Optionally, a low modulus elastomeric material, which has a tensile modulus of less than about 6,000 psi, measured at about 23.degree. C., substantially coats the fiber and yarn of the network.
    Type: Grant
    Filed: December 9, 1985
    Date of Patent: April 12, 1988
    Assignee: Allied Corporation
    Inventors: Gary A. Harpell, Igor Palley, Sheldon Kavesh, Dusan C. Prevorsek
  • Patent number: 4737402
    Abstract: The present invention provides an improved, complex composite article of manufacture which comprises a network of high strength fibers having a tensile modulus of at least about 160 grams/denier and a tenacity of at least about 7 g/denier. An elastomeric material substantially coats each of the individual fibers, and has a tensile modulus of less than about 6,000 psi, measured at 25.degree. C. The coated fibers are provided with at least one additional rigid layer on a major surface of the coated fibers to produce a rigid complex composite. Composites of this construction have improved resistance to environmental hazards, improved impact resistance, and are unexpectedly effective as ballistic resistant articles such as armor plate or helmets.
    Type: Grant
    Filed: December 9, 1985
    Date of Patent: April 12, 1988
    Assignee: Allied Corporation
    Inventors: Gary A. Harpell, Igor Palley, Sheldon Kavesh, Dusan C. Prevorsek
  • Patent number: 4713290
    Abstract: Polyvinyl alcohol of molecular weight over 500,000 (i.e. 1,500,000 to 2,500,000) is spun as a dilute solution (2-15%) in a relatively non-volatile solvent such as glycerin. The resultant gel fiber is extracted with a volatile solvent such as methanol and dried. Upon stretching at one or more stages during the process, fibers of tenacity above 10 g/denier and modulus above 200 g/denier (e.g. 18 and 450, respectively) are produced.
    Type: Grant
    Filed: January 22, 1986
    Date of Patent: December 15, 1987
    Assignee: Allied Corporation
    Inventors: Young D. Kwon, Sheldon Kavesh, Dusan C. Prevorsek
  • Patent number: 4695240
    Abstract: A mini-extruder apparatus for extruding small quantities of material. The apparatus is designed to overcome the problems of excessive heat transfer from the heated portion of the barrel to the feed portion of the extruder barrel and the premature failure of the long thin extruder screws employed in extruders. The mini-extruder includes an extruder barrel having a substantially circumferential, radially extending cavity formed in an isolator portion of the extruder barrel to thermally isolate the feed portion from the heated portion. The mini-extruder also includes a drive system constructed to drive the extruder screw at both ends. The mini-extruder can also be designed as a co-rotating or counter-rotating twin screw extruder where each end of each extruder screw is driven.
    Type: Grant
    Filed: April 4, 1984
    Date of Patent: September 22, 1987
    Assignee: Allied Corporation
    Inventors: Hsin L. Li, Dusan C. Prevorsek
  • Patent number: 4681792
    Abstract: The present invention provides improved, flexible articles of manufacture comprising a plurality of first flexible layers arranged in a first portion of said article, each of said first layers consisting essentially of fibers, the fibers of each of said flat layers comprising fibers having a tensile modulus of at least about 300 g/denier and a tenacity of at least about 15 g/denier and a plurality of second flexible layers arranged in a second portion of said article, each of said second flexible layers comprising fibers, the resistance to displacement of fibers in each of said second flexible layers being greater than the resistance to displacement of fibers in each of said first flexible layers.
    Type: Grant
    Filed: December 9, 1985
    Date of Patent: July 21, 1987
    Assignee: Allied Corporation
    Inventors: Gary A. Harpell, Igor Palley, Dusan C. Prevorsek
  • Patent number: 4663101
    Abstract: Solutions of intermediate molecular weight polymers from about 200,000 to about 4,000,000, such as polyethylene, in a relatively non-volatile solvent are extruded through an aperture at constant concentration and thereafter stretched at a ratio of at least about 3:1 prior to cooling to form a first gel. The first gels are extracted with a volatile solvent to form a second gel, and the second gel is dried to form a low porosity xerogel. Stretching occurs with any one or more of the first gel, second gel or xerogel. The polyethylene products produced by our process include products having a molecular weight between about 200,000 and about 4,000,000 a tenacity of at least about 13 grams/denier, a modulus of at least about 350 gram/denier, a porosity of less than 10% by volume, a crystalline orientation function of at least about 0.95, and a main melting temperature of at least about 140.degree. C.
    Type: Grant
    Filed: January 11, 1985
    Date of Patent: May 5, 1987
    Assignee: Allied Corporation
    Inventors: Sheldon Kavesh, Dusan C. Prevorsek
  • Patent number: 4650710
    Abstract: The present invention provides an improved fabric which comprises at least one network of fibers selected from the group consisting of extended chain polyethylene (ECPE) extended chain polypropylene (ECPP) fibers, extended chain polyvinyl alcohol fibers and extended chain polyacrylonitrile fibers. A low modulus elastomeric material, which has a tensile modulus of less than about 6,000 psi, measured at about 23.degree. C., substantially coats the fibers of the network. Preferably, the fibers have a tensile modulus of at least about 500 grams/denier and an energy-to-break of at least about 22 Joules/gram.
    Type: Grant
    Filed: December 9, 1985
    Date of Patent: March 17, 1987
    Assignee: Allied Corporation
    Inventors: Gary A. Harpell, Igor Palley, Sheldon Kavesh, Dusan C. Prevorsek