Patents by Inventor Kalidas Chakravarti
Kalidas Chakravarti 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).
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Patent number: 6266951Abstract: A knittable, cut-resistant yarn for use in protective wear, such as gloves, arm protectors, aprons, or the like, including a core with at least one strand of flexible, stainless steel wire having a diameter of about 0.002 inches and at least one strand of an anti-microbial treated fiber. A first wrap is wound in one direction about the core and is a polyester fiber having a denier in the range of 40-600 and a second wrap is wound in a second direction about the core which includes at least one strand of a polyester fiber having a denier in the range of 40-600. The anti-microbial treated fiber may be acetate-based, acryl-based or olefinic. The anti-microbial treated fiber contains an anti-microbial agent, such as Microban-B, where the active ingredient is 5 chlor-2-(2,4 dichlorophenoxy) phenol.Type: GrantFiled: January 8, 1999Date of Patent: July 31, 2001Assignee: Whizard Protective Wear Corp.Inventor: Kalidas Chakravarti
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Patent number: 6260344Abstract: A knittable cut resistant yarn for use in protective wear, such as gloves, arm protectors, aprons, or the like, including a core with at least one strand of flexible material selected from the group consisting of stainless steel wire and poly-paraphenylene terephthalamide. The core is wrapped with at least one strand of an antimicrobial treated acrylic fiber. A first wrap is wound in one direction about the core having a denier in the range of about 75 to about 600. Each additional wrap is wound about the core in a different direction. The antimicrobial treated acrylic fiber contains the antimicrobial agent 5-chloro-2-(2,4-dichlorophenoxy)phenol.Type: GrantFiled: July 7, 1999Date of Patent: July 17, 2001Assignee: Whizard Protective Wear Corp.Inventor: Kalidas Chakravarti
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Patent number: 5358648Abstract: Spin finish composition for conventional speed spinning of polyester yarns providing yarn of superior quality, low emissions and no significant deposits on processing equipment, is a non-aqueous composition consisting essentially of from 10 to 70% by weight of a trimethylol or tetramethylol C.sub.1 -C.sub.3 alkane ester wherein all the methylol groups are esterified with C.sub.8 -C.sub.10 saturated carboxylic acid, preferably trimethylol propane tripelargonate, from 10 to 70% by weight of tetraethylene glycol diester of C.sub.8 -C.sub.10 saturated carboxylic acid, preferably tetraethylene glycol diester of decanoic and octanoic acid, from 5 to 50% by weight of low volatility, light viscosity, 15 low surface tension, substantially aromatic-free light mineral oil, preferably consisting essentially of C.sub.12 -C.sub.15 isoparaffic hydrocarbon, and from 2 to 20% by weight of 1H-imidazolium, 1-ethyl-4,5-dihydro-3-(2-hydroxyethyl)-2-(8-heptadecenyl)-, ethyl sulfate.Type: GrantFiled: November 10, 1993Date of Patent: October 25, 1994Assignee: Bridgestone/Firestone, Inc.Inventor: Kalidas Chakravarti
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Patent number: 5232742Abstract: Spin finish concentrate composition and the oil-in-water emulsion made from the concentrate for application for conventional speed or high speed melt spinning processes for producing polyester or polyamide yarns, consists essentially of oil lubricant component, pentaerythritol ester lubricant, ethoxylated sorbitan monooleate of HLB ranging from 6 to 15, anionic antistatic agent, water soluble sulfosuccinate wetting agent, and oil soluble ethoxylated polymethylsiloxane wetting agent having molecular weight of 400 to 700 and an aqueous surface tension value of less than 21 dynes/cm. The concentrate has long term stability. The finish prepared from the concentrate produces excellent quality yarn with virtually no broken filaments, and leaves no deposits on heated draw rolls, relaxation rolls and any yarn guides during spinning and drawing operations.Type: GrantFiled: May 15, 1992Date of Patent: August 3, 1993Assignee: Bridgestone/Firestone, Inc.Inventor: Kalidas Chakravarti
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Patent number: 5128054Abstract: A composition and a process for producing adhesive-active polyester yarn comprising coating polyester fibers with an overcoat finish composition. The process relates to applying the finish to the yarn, forming the coated yarn into cords, and treating the cords with a conventional resorcinol-formaldehyde latex (RFL) dip and subsequently embedding adhesive-active yarn into a rubber article. The composition comprises an aziridine (also called an ethylenimine compound) compound, a diluent, and a wetting agent. The special finish application allows the formation of a coated yarn with improved bond strength, and in particular improved bond strength to rubber particles.Type: GrantFiled: January 2, 1991Date of Patent: July 7, 1992Assignee: Bridgestone/Firestone, Inc.Inventor: Kalidas Chakravarti
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Patent number: 5116682Abstract: A process for producing anti-wicking and water repellant polyester yarns at high processing speeds. Polyester yarn or other heat stable yarn is continuously fed to a coating station, the yarn is then coated with a fluorocarbon polymer emulsion or dispersion and the yarn is dried in an RF oven, heat cured in a coating oven, and then wound.Type: GrantFiled: December 17, 1990Date of Patent: May 26, 1992Assignee: Bridgestone/Firestone, Inc.Inventors: Kalidas Chakravarti, Jamshiid Khalatbari
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Patent number: 4381640Abstract: A process for the production of reinforced rubber articles formed from polyester yarn embedded into rubber stock is disclosed. The process comprises the steps of: (1) treating the yarn with a finish composition which comprises water and a silane having the structural formula: ##STR1## wherein n=2 to 5, and (2) including from about 2 to 50 parts, per hundred parts of rubber, of silica particles in the rubber stock. The reinforced rubber article is preferably a pneumatic passenger tire which has excellent adhesion of tire cord to rubber.Type: GrantFiled: November 17, 1980Date of Patent: May 3, 1983Assignee: Allied CorporationInventors: Kalidas Chakravarti, Stanley D. Lazarus
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Patent number: 4348517Abstract: A fiber finish composition, a process which includes treating polyester yarn therewith and polyester yarn so treated are all disclosed. The fiber finish composition comprises a triglycidyl ether of glycerol; a low viscosity diglycidyl ether having the structural formula ##STR1## wherein R is alkylene or arylene; ethoxylated castor oil; an epoxy silane having the structural formula ##STR2## wherein n=2 to 5; and a solvent. The process comprises the steps of (1) heating the yarn to a temperature of about 150.degree. C. to 230.degree. C. and (2) treating the yarn with the fiber finish composition, preferably utilized as an aqueous overfinish. The yarn is preferably used in tire cords for the construction of pneumatic passenger tires and results in excellent adhesion of tire cord to rubber.Type: GrantFiled: December 9, 1980Date of Patent: September 7, 1982Assignee: Allied Chemical CorporationInventor: Kalidas Chakravarti
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Patent number: 4171422Abstract: High molecular weight linear condensation polyesters are stabilized against deterioration by heat by reacting the polyester in molten form with certain polycarbonates in the presence of a catalytic amount of a phosphonium compound selected from the group consisting of tetra-n-alkylphosphonium acetates and tetra-n-alkylphosphonium halides. For the purpose of this disclosure, polycarbonates are defined as linear polyesters of carbonic acid in which the carbonate groups recur in the polymer chain. In continuous production of the improved polyesters, it is preferred that the polycarbonate and catalyst be added to the process stream with mixing at a point to give 2 to 15 minutes reaction time under superatmospheric pressure before the polyester enters the last polycondensation reactor.Type: GrantFiled: September 11, 1978Date of Patent: October 16, 1979Assignee: Allied Chemical CorporationInventors: Stanley D. Lazarus, Kalidas Chakravarti, Hugh H. Rowan, James G. Neal
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Patent number: 4152318Abstract: High molecular weight linear condensation polyesters are stabilized against deterioration by heat by reacting the polyester in molten form with an epoxy compound having 5 to 25 carbon atoms in the molecule and selected from the group consisting of ##STR1## where R represents the radical remaining after removal of the carboxyl group from a monocarboxylic acid, R.sub.1, R.sub.2, R.sub.3 and R.sub.4 represent hydrogen or hydrocarbon radicals, and n is an integer that can be 0 to 3.Type: GrantFiled: March 20, 1978Date of Patent: May 1, 1979Assignee: Allied Chemical CorporationInventors: Stanley D. Lazarus, Kalidas Chakravarti
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Patent number: 4139521Abstract: High molecular weight linear condensation polyesters are stabilized against deterioration by heat with a stabilizer comprising an N-epoxyalkyl imide of a dicarboxylic acid, having 5 to 20 carbon atoms in the imide molecule and composed of carbon, hydrogen, carbonyl and epoxy oxygen, and imide nitrogen atoms, said epoxy oxygen being linked to adjacent carbon atoms.Type: GrantFiled: April 13, 1978Date of Patent: February 13, 1979Assignee: Allied Chemical CorporationInventors: Stanley D. Lazarus, Kalidas Chakravarti
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Patent number: 4130541Abstract: High molecular weight linear condensation polyesters are stabilized against deterioration by heat by reacting the polyester in molten form with an epoxy compound having 5 to 25 carbon atoms in the molecule and selected from the group consisting of ##STR1## where R represents the radical remaining after removal of the carboxyl group from a monocarboxylic acid, R.sub.1, R.sub.2, R.sub.3 and R.sub.4 represent hydrogen or hydrocarbon radicals, and n is an integer that can be 0 to 3.Type: GrantFiled: March 23, 1978Date of Patent: December 19, 1978Assignee: Allied Chemical CorporationInventors: Stanley D. Lazarus, Kalidas Chakravarti
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Patent number: 4115350Abstract: High molecular weight linear condensation polyesters are stabilized against deterioration by heat by reacting the polyester in molten form with an epoxy compound having 5 to 25 carbon atoms in the molecule and selected from the group consisting of ##STR1## where R represents the radical remaining after removal of the carboxyl group from a monocarboxylic acid, R.sub.1, R.sub.2, R.sub.3 and R.sub.4 represent hydrogen or hydrocarbon radicals, and n is an integer that can be 0 to 3.Type: GrantFiled: July 27, 1977Date of Patent: September 19, 1978Assignee: Allied Chemical CorporationInventors: Stanley David Lazarus, Kalidas Chakravarti