Aromatic Hydrocarbon Contains A Bridged Or Fused Ring Patents (Class 524/485)
  • Patent number: 5401794
    Abstract: It is herein disclosed a process for stabilizing freshly prepared polyketone polymer comprising contacting the polymer with a sufficient quantity of a stabilizing agent such as a polyaromatic or hydroaromatic compound. The inventive process results in stabilized polyketone polymers having and exhibiting improved thermal oxidative stability properties. It is also disclosed a stabilized polymer composition comprising a major amount of a polyketone polymer and a minor amount of a polyaromatic or hydroaromatic compound.
    Type: Grant
    Filed: June 3, 1994
    Date of Patent: March 28, 1995
    Assignee: Shell Oil Company
    Inventor: Carlton E. Ash
  • Patent number: 5399606
    Abstract: A homogenous non-tacky thermosetting plastic powder mixture formed by mixing component A comprising a solid phenol novolac resin powder and a hardener containing a small amount of an oil-like substance liquid at room temperature with component B comprising a liquid resol, fillers and optionally additives which when containing an abrasive are useful for the production of filler-containing shaped elements or resin-bonded grinding elements.
    Type: Grant
    Filed: October 18, 1993
    Date of Patent: March 21, 1995
    Assignee: Rutgerswerke Aktiengesellschaft AG
    Inventors: Michael Konig, Achim Hansen, Arno Gardziella, Josef Suren
  • Patent number: 5371130
    Abstract: A composition of an oil-soluble, olefin-based polymer and an oil-soluble polar polymer having nitrogen functionality, wherein the polymers in combination in oil exhibit incompatibility as evidenced by phase separation, shows improved compatibility by addition to the mixture of certain hydrocarbyl substituted hydroxyaromatic materials.
    Type: Grant
    Filed: October 7, 1993
    Date of Patent: December 6, 1994
    Assignee: The Lubrizol Corporation
    Inventors: Richard M. Lange, Curtis R. Scharf
  • Patent number: 5349005
    Abstract: An olefin thermoplastic elastomer composition prepared by subjecting a composition comprising (a) 100 parts by weight of an ethylene-.alpha.-olefin-non-conjugated diene copolymer rubber having a high molecular weight, the Mooney viscosity (ML 1+4, at 125.degree. C.) of a composition consisting of 100 parts by weight of the copolymer rubber and 75 parts by weight of a mineral oil-type softening agent being 40 or more, (b) from 10 to 500 parts by weight of a crystalline ethylene-propylene block copolymer resin having a melt flow rate of 10 to 50, (c) from 3 to 300 parts by weight of a mineral oil-type softening agent, and (d) from 5 to 100 parts by weight of a low-molecular-weight propylene homopolymer resin having a number-average molecular weight of 2000 to 20000, the weight ratio of the low-molecular-weight propylene homopolymer resin to the crystalline ethylene-propylene block copolymer resin being 0.8 or less, to dynamic vulcanization using, as a vulcanizing agent, from 0.
    Type: Grant
    Filed: February 6, 1992
    Date of Patent: September 20, 1994
    Assignee: Advanced Elastomer Systems, L.P.
    Inventor: Terutaka Tanaka
  • Patent number: 5332773
    Abstract: Highly filled thermoplastic compositions useful as adhesive precoats for carpets are obtained by blending certain ethylene/vinyl acetate copolymers with above 60 wt. % filler and processing oil.
    Type: Grant
    Filed: September 1, 1993
    Date of Patent: July 26, 1994
    Assignee: E. I. Du Pont de Nemours and Company
    Inventor: Franklin R. Baker
  • Patent number: 5331037
    Abstract: Extruded composite solid articles from feed mixtures comprising a substantially uniform mixture of particulate binder material and particulate primary material in which the feed mixture is forced through an extrusion die of substantially uniform cross-section and subject to heat, pressure and cooling which consolidates the feed mixture whereby it emerges from the die as a solid composite article and in which the pressure in the extrusion die is supplied by back-pressuring means external of the die. Solid filter elements of activated carbon particles for a wide variety of filtering applications may be formed.
    Type: Grant
    Filed: April 1, 1993
    Date of Patent: July 19, 1994
    Assignee: Koslow Technologies Corporation
    Inventor: Evan E. Koslow
  • Patent number: 5324768
    Abstract: A coating composition and a method of coating with said composition, with the composition comprising a coating especially suited for sealing metal joints and metal roofs that comprises from about 10% to about 20% of a thermoplastic resin, from about 1.5% to about 3% of a plasticizer, from about 10% to about 20% of a synthetic thermo-plastic rubber, and from about 5% to about 20% of a free flowing silica-alumina glass ceramic filler.
    Type: Grant
    Filed: July 17, 1992
    Date of Patent: June 28, 1994
    Assignee: Inland Coatings Corporation
    Inventor: Douglas G. Walmsley
  • Patent number: 5290842
    Abstract: A pressure sensitive adhesive of a mutually immiscible first elastomer (styrene-butadiene block copolymer) exhibiting a first glass transition temperature and a second elastomer (e.g., a styrene-isoprene-styrene block copolymer) exhibiting a second glass transition temperature greater than the first is tackified by a tackifying system comprising tackifier preferentially miscible with the second elastomer to provide a dynamic mechanical spectrum plot of tangent delta versus temperature in .degree.C. showing two separate and distinct glass transition temperature peaks. The mixture exhibits excellent processability and ambient and low temperature adhesive properties.
    Type: Grant
    Filed: July 27, 1992
    Date of Patent: March 1, 1994
    Assignee: Avery Dennison Corporation
    Inventors: Yukihiko Sasaki, Jesse Ercillo
  • Patent number: 5264476
    Abstract: An olefinic resin composition which is moldable to shaped articles coatable with coating compositions without primers is prepared by blending (A) a cross-linked olefinic thermoplastic elastomer obtained from a homo- or co-polymer of alpha-olefin (C.sub.2-20) and elastomeric copolymer composed of alpha-olefins (C.sub.2-20), (B) a low-molecular weight modified polypropylene having Mn of 2,000-20,000 which is grafted with maleic anhydride and (C) a tackifier.
    Type: Grant
    Filed: December 17, 1992
    Date of Patent: November 23, 1993
    Assignee: Sumitomo Chemical Company, Limited
    Inventors: Akio Daimon, Koichiro Ibuki
  • Patent number: 5252649
    Abstract: The plasticizer constituent in the rubber mixture of the tread member of a pneumatic vehicle tire contains at least partially at least one fatty acid triglyceride, preferably natural rape seed oil in which more than 50% of the fatty acid residues are present as oleic acid residues and an oleic acid/linoleic acid ratio is greater than or equal to 2:1. Sunflower seed oil or natural rape seed oil and triglyceride of oleic acid also can be used as the fatty acid triglycerides. There is thus achieved improved traction upon ice and snow as well as at dry and wet roads in the absence of negative effects on other properties of the tire.
    Type: Grant
    Filed: July 13, 1992
    Date of Patent: October 12, 1993
    Assignee: Semperit Reifen AG
    Inventor: Bernadette Hausmann
  • Patent number: 5227424
    Abstract: A rubber composition for tire treads is disclosed which is designed to exhibit high resistance to skidding on wet, icy and snowy roads. A selected rubber blend of styrene-butadiene rubber and natural rubber and/or polyisoprene rubber is combined with a selected carbon black of specified specific surface areas and also with a selected softener of specified viscosity-gravity constants. The styrene-butadiene rubber consists essentially of two styrene-butadiene block copolymers each having varied styrene and vinyl contents and a specified transition temperature width, one block having a higher glass transition temperature than the other.
    Type: Grant
    Filed: February 18, 1992
    Date of Patent: July 13, 1993
    Assignee: The Yokohama Rubber Co., Ltd.
    Inventors: Akinori Tokieda, Shinji Kawakami, Yasushi Kikuchi, Makoto Misawa, Yoshinori Hunayama
  • Patent number: 5187224
    Abstract: A blend which comprises a partially crosslinked product of a mixture of an oil-extended olefinic copolymer rubber comprising an olefinic copolymer rubber having a 100.degree. C. Mooney viscosity 150-350, a polyolefin resin, a selectively hydrogenated block copolymer, and a specific mineral oil type softening agent has excellent flexibility of less than 45 in Shore A hardness. The blend is not tacky, nor does the softening agent bleed. An anti-static agent for polyolefins and/or a higher fatty acid amide may be included in the composition.
    Type: Grant
    Filed: April 8, 1991
    Date of Patent: February 16, 1993
    Assignee: Sumitomo Chemical Company, Limited
    Inventors: Tatsuo Hamanaka, Tadashi Hikasa, Koichiro Ibuki
  • Patent number: 5183705
    Abstract: This invention provides a normally tacky pressure-sensitive adhesive composition comprising (1) a radial teleblock copolymer having at least three monoalkenyl arene polymer blocks and a branched elastomeric conjugated diene polymer block, (2) a tackifying resin, and (3) from about 5 to about 20 parts by weight extending oil per 100 parts by weight of radial copolymer. The copolymer preferably has a molecular weight of about 180,000 to about 250,000, as expressed in polystyrene equivalent molecular weight units. The monoalkenyl arene polymer blocks preferably comprise from about 17% to about 23% by weight of the total molecular weight of the copolymer. The preferred polymer for the monoalkenyl arene block is polystyrene; the preferred polymer for the elastomeric conjugated diene block is polyisoprene.
    Type: Grant
    Filed: February 28, 1992
    Date of Patent: February 2, 1993
    Assignee: Minnesota Mining and Manufacturing Company
    Inventors: Ronald B. Birkholz, Mark D. Glad
  • Patent number: 5169893
    Abstract: The invention is composition useful for preparing articles from syndiotactic polystyrene, or a mixture of syndiotactic polystyrene and isotactic polystyrene which comprises a homogeneous mixture of;A. syndiotactic polystyrene, or a mixture of syndiotactic polystyrene and isotactic polystyrene; andB. a solvent for the polystyrene wherein said solvent is a liquid at temperatures at which articles can be formed from the polystyrene:wherein the mixture is viscous enough to form articles from the polystyrene.
    Type: Grant
    Filed: June 19, 1991
    Date of Patent: December 8, 1992
    Assignee: The Dow Chemical Company
    Inventor: Henry N. Beck
  • Patent number: 5145897
    Abstract: The invention relates to a polynorbornene-based rubbery composition with improved thermal behaviour, comprising a mixture of at least 50% by weight of polynorbornene and not more than 50% by weight of another rubber, the said mixture having been vulcanized by means of effective quantity of at least one compound: ##STR1## where R.sub.1, R.sub.2 =CH.sub.n X.sub.3-n, with X=F, Cl or Br and n = integer from 0 to 2; the invention also relates to a thermoplastic composition comprising 10-90 parts by weight (pw) of at least one olefin-based crystalline polymer (A), from 90-10 pw of a mixture (B) of at least 50% by weight of polynorbornene and not more than 50% by weight of another rubber, and a sufficient quantity of plasticiser for polynorbornene to lower its glass transition temperature to the range of rubbers, the sum of (A) and of (B) being equal to 100 pw and (B) being vulcanized by means of an effective quantity of at least one compound (I).
    Type: Grant
    Filed: May 1, 1991
    Date of Patent: September 8, 1992
    Assignee: Atochem
    Inventors: Gabriel Levif, Frederic Coupe
  • Patent number: 5132348
    Abstract: A tread rubber composition for high-speed running tires comprises a particular halogenated modified styrene-butadiene copolymer having p-halomethylbenzoyl group as a starting rubber and contains particular amounts of carbon black, process oil and diamine, and has excellent heat resistance and wear resistance.
    Type: Grant
    Filed: June 28, 1990
    Date of Patent: July 21, 1992
    Assignee: Bridgestone Corporation
    Inventors: Tadashi Saito, Joji Yatsunami, Ichiro Wada, Toshiki Takizawa
  • Patent number: 5112398
    Abstract: An ink jet ink composition and method of printing on plain paper are provided wherein the composition comprises a mixture of a nonaqueous solvent (e.g. selected glycol ethers), a resin (e.g. an ethylene-vinyl acetate copolymer) which is substantially completely soluble in the solvent at elevated operation temperatures but substantially insoluble in the solvent at room temperature and a dyestuff which is soluble in the resin at room temperature and above but substantially insoluble in the solvent at room temperature. The ink composition is fluid at room temperature, and has very low viscosity at elevated operating temperatures.
    Type: Grant
    Filed: March 27, 1991
    Date of Patent: May 12, 1992
    Assignee: Xaar Limited
    Inventor: Jurgen M. Kruse
  • Patent number: 5112900
    Abstract: An elastomeric composition is formed of at least two, and preferably three, S-EB-S elastomeric triblock copolymers having different solution viscosity/copolymer concentration relationships, and a sufficient amount of a mineral oil plasticizer to achieve excellent tactility with acceptable strength. To prepare articles such as medical film protective devices, the elastomeric composition is dissolved in a sufficient amount of a solvent to permit dip forming. A form having the shape of the desired product is dipped into the solution to build up a film of the elastomeric composition on the form. The dip-formed elastomeric films are free of pinholes and resistant to oxidative and ozone attack. The films are particularly suitable for use in products such as examination, surgical, and industrial gloves and condoms.
    Type: Grant
    Filed: November 28, 1990
    Date of Patent: May 12, 1992
    Assignee: Tactyl Technologies, Inc.
    Inventors: Douglas A. Buddenhagen, Norman R. Legge, Gunter Zscheuschler
  • Patent number: 5104914
    Abstract: It is the object of this invention to provide a method for the preparation of an antiblocking agent which is effective in its antiblocking activity but is considerable less visible in photographic enlargements made from the film containing the antiblock of this invention.There is described a process for the preparation of monodispersed polymer particles between 5 and 10 microns in diameter which comprises preparing a dispersion of monosized seed polymer particles and then adding to this dispersion an ethylenically unsaturated monomer which is different from the monomer used to prepare the seed polymer particles, together with a polymerization initiator and completing the polymerization, the refractive index of one of the polymers produced being greater than 1.54 and the refractive index of the other polymer being less than 1.54.The refractive index of gelatin is 1.54. There is produced by the process of the present invention a particle which comprises two polymers.
    Type: Grant
    Filed: May 10, 1990
    Date of Patent: April 14, 1992
    Assignee: Ilford Limited
    Inventors: Peter J. Elton, John L. Cawse
  • Patent number: 5019620
    Abstract: An elastic crosslinked metathesis polymer composition is disclosed comprised of a copolymer of a norbornene-type compound which metathesis polymerizes to a linear polymer and a norbornene-type compound having a second double bond of similar reactivity which forms a crosslinked polymer, and a hydrocarbon-based extending oil. Norbornene and dicyclopentadiene are typical comonomers. Polymerization is carried out by a RIM or resin injection molding process.
    Type: Grant
    Filed: September 27, 1990
    Date of Patent: May 28, 1991
    Assignee: Hercules Incorporated
    Inventors: Zenichiro Endo, Shigeyoshi Hara
  • Patent number: 4980394
    Abstract: The invention relates to foundry moulding compositions useful for producing moulds for the manufacture of metal castings wherein the moulds are capable of giving castings with good surface finish without the need for conventional separate blacking applications. A foundry moulding composition of the invention comprises refractory material such as sand, alkali phenol-formaldehyde resole resin solution, carbonifiable material such as styrenated phenol, and an effective amount of an organic ester for hardening the composition. In another embodiment, the invention is a binder composition comprising alkali phenol-formaldehyde resole resin solution and carbonifiable material capable of being hardened by reaction with organic ester. In another embodiment, the invention is a curing additive for a foundry binder comprising carbonifiable material and liquid ester such as gamma-butyrolactone, and the like.
    Type: Grant
    Filed: January 11, 1989
    Date of Patent: December 25, 1990
    Assignee: Borden (UK) Limited
    Inventors: Peter H. R. B. Lemon, Jeffrey D. Railton, Derek W. Baker, John Ireland
  • Patent number: 4925894
    Abstract: Elastomer compositions which are particularly adapted for forming tire treads having low rolling resistance and good wet and dry grip traction comprise an elastomer having a Tg of -60.degree. C. or higher and low viscosity aromatic oil. Especially useful aromatic oils are those having a Saybolt Universal viscosity at 100.degree. F. of from about 50 to about 2500 SUS.
    Type: Grant
    Filed: February 14, 1986
    Date of Patent: May 15, 1990
    Assignee: Bridgestone/Firestone, Inc.
    Inventor: Shingo Futamura
  • Patent number: 4912148
    Abstract: Thermoplastic elastomer having excellent processability and physical properties is provided by the composition:(A) monoolefin copolymer rubber: 20 to 90 parts by weight(B) crystalline poly-alpha olefin resin: 5 to 70 parts by weight(C) mineral oil-type oil: 5 to 100 parts by weight with respect to (A) plus (B)(D) polyolefin-type wax: 5 to 60 parts by weight with respect to (A) plus (B)(E) butyl rubber: 0.1 to 10 parts by weight with respect to (A) plus (B)in the extruder and then are dynamically partial cross-linked together with a certain amount of organic peroxide, cross-linking aids and coupling agents in the extruder.
    Type: Grant
    Filed: July 15, 1988
    Date of Patent: March 27, 1990
    Assignee: Tong Yang Nylon Co., Ltd.
    Inventors: Jae K. Kim, Sung M. Lee, Young D. Kim
  • Patent number: 4842781
    Abstract: Disclosed is a colored polarizing film having excellent durability which comprises (a) an organic polymer film or sheet and (b) at least one dichroic dye having an azo, anthraquinone, thioindigo, perylene or phthalone structure containing no water-soluble group. Also disclosed is a method of making a colored polarizing film using an organic polymer film or sheet formed of a polyamide or polyester resin, which comprises the steps of (a) blending (preferably, dry blending) a dichroic dye with the resinous polymer in advance, (b) melting the resulting blend and forming it into a film, and then (c) stretching the film in at least one direction.
    Type: Grant
    Filed: January 11, 1988
    Date of Patent: June 27, 1989
    Assignee: Mitsui Toatsu Chemicals, Inc.
    Inventors: Tsutomu Nishizawa, Yasuyuki Yamada, Junichi Fujio, Shin Hosonuma
  • Patent number: 4792584
    Abstract: An adhesive composition comprising100 parts by weight of a block copolymer (a) containing of at least one polymer block composed mainly ofa vinyl aromatic hydrocarbon and at least one polymer block composed mainly of butadiene in which(i) the vinyl aromatic hydrocarbon content [S] is 10 to 30% by weight,(ii) the 1,2-vinyl content of butadiene portion [V] is 20 to 50%, and(iii) the relationship between said vinyl aromatic hydrocarbon content [S] and said 1,2-vinyl content of butadiene portion [V] satisfies the formula,:40.ltoreq.[S]+[V].ltoreq.7040 to 200 parts by weight of a tackifier (b), and, optionallyvarious stabilizers, and a process for producing said composition.
    Type: Grant
    Filed: April 23, 1987
    Date of Patent: December 20, 1988
    Assignee: Asahi Kasei Kogyo Kabushiki Kaisha
    Inventors: Toshinori Shiraki, Yasuo Hattori, Masao Karouji
  • Patent number: 4759801
    Abstract: A method for preparing a pigment preparation comprising kneading a pigment presscake (comprising a pigment and water and/or one or more organic liquids) at a temperature in the range 80.degree. to 200.degree. C. under vacuum together with a thermoplastic material, thereby at the same time removing the water and/or any organic liquids present. These preparations are useful for coloring polymeric material.
    Type: Grant
    Filed: July 10, 1986
    Date of Patent: July 26, 1988
    Assignee: Sandoz Ltd.
    Inventors: Jurgen Goldmann, Bansi L. Kaul
  • Patent number: 4753861
    Abstract: Erasable optical memories for storing information are prepared from organic materials having two stable crystalline forms. Each crystalline form has at least one different optical characteristic and the materials are reversibly thermally convertible between the crystalline forms. Information is recorded or erased with a laser beam that heats a film of the organic material in a local area to change the crystalline form. Information may also be recorded or erased by melting a local area or all of the film and quickly cooling it to restore the original crystalline form. Examples of such organic compounds are biaryl compounds, such as binaphthyls, bianthryls and biquinolyls.
    Type: Grant
    Filed: December 19, 1986
    Date of Patent: June 28, 1988
    Assignee: The Standard Oil Company
    Inventors: Dean T. Tsou, Marc W. Blachman, James D. Burrington
  • Patent number: 4620855
    Abstract: N-acylated aminohydrocarbyl sulfonic acids or acid derivative compositions are described which are characterized by the presence with the structure of at least one acyl, acylimidoyl or acyloxy group attached to the amino nitrogen, said groups being derived from at least one of the carboxylic acid groups contained in an interpolymer of (i) at least one vinyl aromatic monomer and (ii) at least one alpha, beta-unsaturated acid or derivative thereof. Aqueous systems also are described which comprise at least about 40% of water and the N-acylated amino hydrocarbyl sulfonic acid or salt composition of the invention. The hydrocarbyl sulfonic acid or salt compositions of the present invention are useful as emulsifiers, thickeners, dispersants, etc. in the aqueous systems, and the compositions also are useful as additives in fuels and lubricants.
    Type: Grant
    Filed: November 7, 1984
    Date of Patent: November 4, 1986
    Assignee: The Lubrizol Corp.
    Inventor: William A. Higgins
  • Patent number: 4567211
    Abstract: Plasticized polyphosphazene compositions exhibiting excellent flame resistance and low smoke output are disclosed. The plasticizers are resinous alkylated naphthalenes condensed with formaldehyde which are characterized by methylene bridges between naphthalenic rings with softening points ranging from 28.degree. F. to 158.degree. F.
    Type: Grant
    Filed: March 4, 1985
    Date of Patent: January 28, 1986
    Assignee: The Firestone Tire & Rubber Company
    Inventors: Arthur E. Oberster, John C. Vicic
  • Patent number: 4548735
    Abstract: The present invention relates to oil solubilization agents for solubilizing oil into an aqueous solution in which the oil solubilization agents are diblock polymers of t-butylstyrene/metal styrene sulfonate and triblock polymers of t-butylstyrene/metal styrene sulfonate/t-butylstyrene.
    Type: Grant
    Filed: December 29, 1982
    Date of Patent: October 22, 1985
    Assignee: Exxon Research and Engineering Co.
    Inventors: Jan Bock, Paul L. Valint, Jr.
  • Patent number: 4483951
    Abstract: This disclosure relates to novel adhesive compositions and composite structures utilizing the same, wherein said adhesive compositions contain an elastomer, a chemically compatible ethylenically unsaturated monomer, a tackifier, an adhesion promoter, and optionally, pigments, fillers, thickeners and flow control agents which are converted from the liquid to the solid state by exposure to high energy ionizing radiation such as electron beam. A particularly useful application for such adhesive compositions comprises the assembly of certain composite structures or laminates consisting of, for example, a fiber flocked rubber sheet and a metal base with the adhesive fulfilling the multiple functions of adhering the flocked fiber to the rubber sheet as well as adhering the rubber sheet to the metal base.
    Type: Grant
    Filed: December 2, 1981
    Date of Patent: November 20, 1984
    Assignee: The Standard Products Company
    Inventor: Walter Brenner
  • Patent number: 4458047
    Abstract: A novel process for making novel naphthalene hydrodimer mixtures which contain PTB in varying amounts and have improved plasticizing properties over PTB alone. The improved plasticizing composition is prepared by contacting a mixture of a hydronaphthalene (e.g., tetralin or an alkyltetralin) and naphthalene or an alkylnaphthalene with a strong acid catalyst. Another embodiment of the invention is the plasticized composition.
    Type: Grant
    Filed: June 7, 1982
    Date of Patent: July 3, 1984
    Assignee: Sun Tech, Inc.
    Inventor: William D. Vanderwerff
  • Patent number: 4444938
    Abstract: Phenyltetralylbutane (PTB) is used to plasticize polyvinylchloride (PVC) resins. The PTB in one embodiment is prepared by refluxing tetralin an flowing condensed vapors of the tetralin over a bed of strongly acidic catalyst, which may for example be a synthetic acid "Y" type zeolite. In one embodiment, the PTB is used as a secondary plasticizer, with a primary plasticizer such as di(2-ethyl)hexyl phthalate.
    Type: Grant
    Filed: June 7, 1982
    Date of Patent: April 24, 1984
    Assignee: Sun Tech, Inc.
    Inventors: Eugene L. Coggins, William D. Vanderwerff
  • Patent number: 4371652
    Abstract: This invention relates to unique and novel compositions based on chemically combining a sulfonated polymer and a tertiary amine terminated polylactone composition. The resulting amine neutralized sulfonated polymer compositions have a variety of uses including those as diverse as adhesive agents, thermoplastic elastomers, additive uses wherein these materials can be utilized to compatibilize two different polymers which are normally incompatible. These compositions can also be blended with fillers and/or oils when the sulfonated polymer is elastomeric. The materials display thermoplastic character.
    Type: Grant
    Filed: December 21, 1981
    Date of Patent: February 1, 1983
    Assignee: Exxon Research and Engineering Co.
    Inventor: Pawan K. Agarwal