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: 4403012
    Abstract: Articles such as vests, helmets and structural elements containing a network of ultrahigh molecular weight, high strength, high modulus polyethylene or polypropylene fibers. The fibers, and especially polyethylene fibers of 15, 20, 25, 30 or more g/denier tenacity, and 300, 500, 1000, 1500 or more g/denier tensile modulus impart exceptional ballistic resistance to the articles in spite of the melting points, e.g. 145.degree.-151.degree. C. for the polyethylene fibers and 168.degree.-171.degree. C. for the polypropylene fibers, which are high for these polymers, but substantially lower than the 200.degree. C. or more melting point previously thought necessary for good ballistic resistance.
    Type: Grant
    Filed: March 19, 1982
    Date of Patent: September 6, 1983
    Assignee: Allied Corporation
    Inventors: Gary A. Harpell, Sheldon Kavesh, Igor Palley, Dusan C. Prevorsek
  • Patent number: 4398018
    Abstract: A thermotropic poly(ester carbonate) containing diacyl moieties such as terephthalate and carbonate moieties as well as dihydroxy-derived moieties is useful for forming fibers or films. The dihydroxy-derived moieties are at least 40% derived from t-butylhydroquinone, with hydroquinone and methylhydroquinone being exemplary second components. The polymers can be prepared by melt, solution or interfacial polymerization, are liquid crystalline in the melt and have glass transition temperatures above 100.degree. C.
    Type: Grant
    Filed: December 21, 1981
    Date of Patent: August 9, 1983
    Assignee: Allied Corporation
    Inventors: Murali K. Akkapeddi, Bruce T. DeBona, Yu-Chin Lai, Dusan C. Prevorsek
  • Patent number: 4374973
    Abstract: Polycarbonate copolymers from bisphenol-A containing terephthalate moieties constituting 5 or 10 mol percent of the polymer, whereby after long exposure to working temperature the polymer retains Izod impact resistance of at least 9 ft. -lbs. per inch of notch.
    Type: Grant
    Filed: July 15, 1981
    Date of Patent: February 22, 1983
    Assignee: Allied Corporation
    Inventors: Dusan C. Prevorsek, Bruce T. DeBona, Yali Kesten
  • Patent number: 4356138
    Abstract: Production of polyethylene filaments of tenacity at least 30 g/d from a hot, supersaturated solution of high viscosity polyethylene having intrinsic viscosity of at least 11 dl/g, by contacting a length of such filament (functioning as a seed) simultaneously with a stationary arcuate surface and with such polyethylene solution, and withdrawing the filament through the solution in sliding contact around the surface at a rate reaching at least 30 cm per minute thereby producing tension and inducing crystal growth from the solution onto the filament, with increase of tension up to a steady state tension of at least 70 grams. More particularly the polyethylene has intrinsic viscosity of 17-28 dl/g, the solvent is xylene, the surface is composed of PTFE, the polyethylene concentration is 0.1 to 0.5 wgt.
    Type: Grant
    Filed: January 15, 1981
    Date of Patent: October 26, 1982
    Assignee: Allied Corporation
    Inventors: Sheldon Kavesh, Dusan C. Prevorsek, Donald G. Wang
  • Patent number: 4336356
    Abstract: Partially unsaturated polymers are dissolved in a two component solvent comprising a first component having a reactivity toward ozone less than carbon-carbon double bonds but more reactive than carbon-carbon single bonds and a second component being inert toward ozone. Introduction of ozone into the solution produces ozonides which are readily cleft into difunctional aliphatic species that can be converted to e.g. carboxy-terminated or multifunctional carboxy substituted aliphatic compounds. These may be used as monomeric species in various polymerization schemes as such, in preparation of polyamides, for example, or may be reduced to aldehydes or alcohols to be used in the preparation of such polymers as polyesters, polyurethanes, poly (Schiff bases), etc. The carboxylated products may also be employed as ionomers, which are useful as surfactants. Monocarboxyl terminated polyethylene having a number average molecular weight of from about 4,000 to 100,000 are provided.
    Type: Grant
    Filed: August 25, 1980
    Date of Patent: June 22, 1982
    Assignee: Allied Corporation
    Inventors: Shaul M. Aharoni, Dusan C. Prevorsek, George J. Schmitt, Gary A. Harpell, Lester T. C. Lee
  • Patent number: 4334045
    Abstract: A monomeric aromatic dicyanate is purified to remove color forming impurities, combined with a zinc salt catalyst and cured first below 200.degree. C. and then for a limited time at or above 200.degree. C., either alone or in admixture with or on a thermoplastic polymer. For example, purified 2,2-bis(4-cyanatophenyl)propane is purified, combined with a poly(ester carbonate) and zinc chloride, and then cured at increasing temperatures from 150.degree. C. to 250.degree. C.
    Type: Grant
    Filed: December 5, 1980
    Date of Patent: June 8, 1982
    Assignee: Allied Corporation
    Inventors: Tse C. Wu, Dusan C. Prevorsek, David H. Wertz
  • Patent number: 4310652
    Abstract: Poly(ester aromatic dihydric alcohol) polymers having carbonate moieties, aromatic or cycloaliphatic dicarboxylic acid moieties and carbonate moieties and having high glass transition temperatures (over 100.degree. C.) and being melt processable. At least part of the aromatic dihydric alcohol moieties have the 4-carbon of each of two phenoxies covalently bonded to the same ring carbon of a carbocyclic or heterocyclic moiety. Representative poly(ester carbonates) are formed from bisphenol-A, phenolphthalein, terephthaloyl chloride and phosgene.
    Type: Grant
    Filed: March 24, 1980
    Date of Patent: January 12, 1982
    Assignee: Allied Chemical Corporation
    Inventors: Bruce T. DeBona, Dusan C. Prevorsek
  • Patent number: 4297878
    Abstract: A method of measuring the coefficient of radial damping per unit length of a tire wall at a predetermined frequency of strain component is applied at a predetermined frequency and amplitude to a segment of the tire wall, the strain being applied in a direction substantially normal to the segment at the point where the strain is applied. The stress on the tire wall segment is continuously measured in a direction substantially parallel to the direction in which the strain component is applied and at a point spaced from the point where strain is applied in a direction along the segment. The coefficient of radial damping per unit length of wall is calculated from this data.
    Type: Grant
    Filed: March 7, 1980
    Date of Patent: November 3, 1981
    Assignee: Allied Corporation
    Inventors: Dusan C. Prevorsek, Young D. Kwon
  • Patent number: 4191790
    Abstract: Bisphenol-A/terephthalate/carbonate copolymer substrate in direct adhesive contact with a coating layer of polymerized allyl diglycol carbonate, ("ADGC") without substantial penetration of the copolymeric substrate by the coating layer. The coated article is prepared by forming a layer of monomeric ADGC on the substrate, then polymerizing the ADGC by free-radical initiation at temperatures maintained below successively higher limits as the polymerization progresses, whereby to avoid substantial penetration of the substrate by ADGC or its polymers. The resulting article, such as a clear sheet or plate, is abrasion resistant.
    Type: Grant
    Filed: August 8, 1978
    Date of Patent: March 4, 1980
    Assignee: Allied Chemical Corporation
    Inventors: Daniel C. Chung, Dusan C. Prevorsek
  • Patent number: 4165634
    Abstract: An improved apparatus and process are described for measuring linear and non-linear viscoelastic properties of viscoelastic materials such as nylon, polyester tire cord, rubber, rubber-tire cord composites and the like. The properties are determined by subjecting a sample material to a constant-rate strain displacement having a small amplitude high frequency sinusoidal strain displacement superimposed thereon, and analyzing the overall resulting material stress. The obtained properties can be used to predict and estimate actual end use characteristics of the material such as longevity and mechanical loss during performance. In the case of tire cord, this latter characteristic can be surprisingly related to efficiency of fuel consumption in automotive vehicles.
    Type: Grant
    Filed: February 6, 1978
    Date of Patent: August 28, 1979
    Assignee: Allied Chemical Corporation
    Inventors: Dusan C. Prevorsek, Young D. Kwon, Raj K. Sharma
  • Patent number: 4157360
    Abstract: A composition is described, useful as a thermoformable polymer, for producing shaped articles having high yield and impact strengths, good heat resistance, and good solvent resistance. The composition, which is cured, contains a crosslinked polycyanurate network polymer in which a high molecular weight thermoplastic polymer, such as a polyestercarbonate, is finely dispersed. The composition possesses a Vicat softening temperature (ASTM 1525) of at least about 10.degree. C. above that of said thermoplastic polymer alone, and an elongation-at-break value (ASTM D-638, at room temperature) at least twice that of said crosslinked polymer alone. Due to the high yield strength, lighter structural articles and components can be fabricated from the composition possessing high structural strength.
    Type: Grant
    Filed: April 26, 1978
    Date of Patent: June 5, 1979
    Assignee: Allied Chemical Corporation
    Inventors: Dusan C. Prevorsek, Daniel C. Chung
  • Patent number: 4156069
    Abstract: Copolymers consisting of bisphenol-A ("BPA"), terephthalate ("TP"), and carbonate moieties in mol ratio from 2:0.8:1.2 to 2:1.3:0.7, which are melt processable in the sense of (a) showing no more than 10% change in viscosity number upon compression molding for 10 minutes at 320.degree. C. to form a plaque, (b) developing, in 2% (gm./ml.) DCM solution, a "yellowness index" of no more than 10 as observed by ASTM Test No. D-1925, using a 2 cm. path length; which copolymers approximate in properties the alternating copolymer consisting of the above moieties, as indicated by their having viscosity numbers ("I.V.") in the range between 0.6 and 1.5 dl./gm. and T.sub.G of 170.degree. to 194.degree. C., with T.sub.G vs. I.V. relationship conforming to the formula, T.sub.G =192-(11.5/I.V.)+9 and with difference of (T.sub.G -HDT) of not over 15.degree. C.; having Izod impact resistance (ft.-lb. per inch of notch) at 25.degree. C. of at least 5; and being essentially free of pyridine and of anhydride linkages.
    Type: Grant
    Filed: February 1, 1977
    Date of Patent: May 22, 1979
    Assignee: Allied Chemical Corporation
    Inventors: Dusan C. Prevorsek, Yali Kesten
  • Patent number: 4150567
    Abstract: By wheel testing two tires having different construction parameters, e.g. different tire cords and measuring the temperatures at a few points within each tire body; and by measurement with a high strain dynamic viscoelastometer, the heat generation rate and dynamic tensile moduli (at various temperatures, strain frequencies and tensions) of the cords and rubber used in each tire are determined, where the values of the exponents "X" in the general equation relating cyclic strain amplitude, S, in the tire cord and in the rubber of each tire vs. the dynamic tensile moduli, E, for cords and rubber, at given temperature can be determined in the form: S.sub.A /S.sub.B=( E.sub.B /E.sub.A).sup.X.
    Type: Grant
    Filed: June 29, 1978
    Date of Patent: April 24, 1979
    Assignee: Allied Chemical Corporation
    Inventors: Dusan C. Prevorsek, Young D. Kwon, Raj K. Sharma
  • Patent number: 4137218
    Abstract: A thermoplastic benzophenone polyester consisting essentially of recurring units of the formula: ##STR1## having an intrinsic viscosity of at least 0.85 deciliter/gram as measured in 1:1 phenol/tetrachloroethane at 25.degree. C, is useful for making shaped articles having high impact strength.A process for preparing a thermoplastic polyester according to the above formula is also described which comprises the steps of (a) adding a solution of 4,4'-benzophenonedicarboxylic acid halide in an inert, water-immiscible organic solvent to a basic aqueous solution of a salt of 2,2-bis(4'-hydroxyphenyl)propane to form and precipitate the polyester during the addition and (b) recovering the precipitated polyester.There is also provided a shaped article prepared from the polyester having an impact strength of at least about 2 ft.lb./in. of notch as measured by the Izod impact test, ASTM D-256-56.
    Type: Grant
    Filed: June 17, 1977
    Date of Patent: January 30, 1979
    Assignee: Allied Chemical Corporation
    Inventors: Dusan C. Prevorsek, Leon Segal
  • Patent number: 4056973
    Abstract: An apparatus and method for testing viscoelastic solids, such as tire cord. The apparatus includes: holding means, pretension means, first and second displacement generators, and mechanical-electrical transforming means. The holding means holds the material in a predetermined position. The pretension means applies tension during testing. The first displacement generator has an eccentric means for applying cyclic displacement. The second displacement generator applies cyclic displacement to the material co-directional with that applied by the first displacement generator, but of smaller amplitude and higher frequency. The mechanical-electrical transforming means transforms mechanical motion into electrical signals, such as a stress signal, a strain signal and a differentiated strain signal.
    Type: Grant
    Filed: December 13, 1976
    Date of Patent: November 8, 1977
    Assignee: Allied Chemical Corporation
    Inventors: Dusan C. Prevorsek, Young D. Kwon, Raj K. Sharma
  • Patent number: 4055606
    Abstract: Novel copolyester-polyepoxide compositions possessing a high green strength and tack before curing and characterized by having a single discernible glass transition temperature are produced. The compositions are composed of a copolyester and a polyepoxide mixture containing high, intermediate and low molecular weight components. They are especially useful as gap-filling adhesives and for various other adhesive applications. Methods of preparation are also described.
    Type: Grant
    Filed: June 21, 1976
    Date of Patent: October 25, 1977
    Assignee: Allied Chemical Corporation
    Inventors: Dusan C. Prevorsek, Shaul M. Aharoni