Patents by Inventor Avinash C. Mehta
Avinash C. Mehta 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: 5705312Abstract: There is described a photographic system wherein development of an exposed photosensitive element is carried out in the presence of a quaternary pyridinium compound which has a fused 5 - to 12 - member saturated carbocyclic ring attached to the 2 and 3 positions of the pyridine ring.Type: GrantFiled: November 25, 1996Date of Patent: January 6, 1998Assignee: Polaroid CorporationInventors: Donna J. Guarrera, Neil C. Mattucci, Avinash C. Mehta, Lloyd D. Taylor, John C. Warner
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Patent number: 5571656Abstract: There is described a multicolor diffusion transfer film unit having a plurality of different color image components, each of which includes a color-sensitive silver halide emulsion in association with a corresponding image dye-providing material and a first silver halide developer which takes part in photographic development to provide an imagewise pattern of diffusible image dye-forming material as a function of photoexposure. At least one of said color image components includes a second silver halide developer, or a precursor thereof, which is capable of developing silver halide indiscriminately and which is made available after photographic development in the color image component in which it is located is substantially completed.Type: GrantFiled: February 9, 1996Date of Patent: November 5, 1996Assignee: Polroid CorporationInventors: Edward D. Kingsley, Emmett S. McCaskill, Avinash C. Mehta, Kenneth C. Waterman
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Patent number: 4946964Abstract: There is described a photographic system wherein development of an exposed photosensitive element with an aqueous alkaline photographic developing composition is effected in the presence of a compound represented by the formula ##STR1## wherein R is --OH, --OR.sub.4, --NH.sub.2 --NHR.sub.5 or --NR.sub.4 R.sub.6 ; R.sub.1 is hydrogen, --NH.sub.2, alkyl, substituted alkyl, aryl or substituted aryl; R.sub.2 and R.sub.3 each independently is hydrogen, alkyl, aralkyl or aryl; R.sub.4 is a protecting group which can be removed in the presence of a base; R.sub.5 is an activating group which can render the neighboring hydrogen atom acidic; R.sub.6 is an electron withdrawing group which is capable of stabilizing the negative charge on the nitrogen atom which is produced upon removal of R.sub.4 upon contact with alkali; and PHOTO is a photographically useful group.Type: GrantFiled: December 11, 1987Date of Patent: August 7, 1990Assignee: Polaroid CorporationInventors: Roger A. Boggs, John B. Mahoney, Avinash C. Mehta, William C. Schwarzel, Lloyd D. Taylor
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Patent number: 4888273Abstract: Silver halide emulsions containing tabular silver halide grains are stabilized by the employment of a compound of the formula ##STR1## where R is --SO.sub.2 NH.sub.2, In a preferred embodiment an azaindene is also employed.Type: GrantFiled: February 26, 1988Date of Patent: December 19, 1989Assignee: Polaroid CorporationInventors: Richard S. Himmelwright, Avinash C. Mehta, Lloyd D. Taylor
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Patent number: 4743533Abstract: There is described a photographic system wherein development of an exposed photosensitive element with an aqueous alkaline photographic developing composition is effected in the presence of a compound represented by the formula ##STR1## wherein R is --OH, --OR.sub.4, --NH.sub.2 --NHR.sub.5 or --NR.sub.4 R.sub.6 ; R.sub.1 is hydrogen, --NH.sub.2, alkyl, substituted alkyl, aryl or substituted aryl; R.sub.2 and R.sub.3 each independently is hydrogen, alkyl, aralkyl or aryl; R.sub.4 is a protecting group which can be removed in the presence of a base; R.sub.5 is an activating group which can render the neighboring hydrogen atom acidic; R.sub.6 is an electron withdrawing group which is capable of stabilizing the negative charge on the nitrogen atom which is produced upon removal of R.sub.4 upon contact with alkali; and PHOTO is a photographically useful group.Type: GrantFiled: March 31, 1986Date of Patent: May 10, 1988Assignee: Polaroid CorporationInventors: Roger A. Boggs, John B. Mahoney, Avinash C. Mehta, William C. Schwarzel, Lloyd D. Taylor
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Patent number: 4709041Abstract: Compounds of the formula ##STR1## wherein R is hydrogen or a hydroxy-protecting group are disclosed. The compounds are versatile intermediates which can be derivatized by reaction of the formyl group to provide a wide variety of ultraviolet-absorbing substituted 2-(2-hydroxyphenyl)-2H-benzotriazoles.Type: GrantFiled: August 25, 1986Date of Patent: November 24, 1987Assignee: Polaroid CorporationInventor: Avinash C. Mehta
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Patent number: 4631327Abstract: Polymers comprising recurring units having cyclic .beta.-elimination moieties capable of undergoing .beta.-elimination in an alkaline environment and are disclosed for use in diffusion control layers in diffusion transfer photographic products.Type: GrantFiled: July 10, 1984Date of Patent: December 23, 1986Assignee: Polaroid CorporationInventor: Avinash C. Mehta
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Patent number: 4593108Abstract: There are disclosed novel compounds which are represented by the formula ##STR1## wherein X represents the nonmetallic atoms necessary to form a nucleus which completes a 5- or 6-membered heterocyclic moiety, R is H, an alkali metal or a group which is cleavable in aqueous alkaline medium and Z is H, alkyl having from 1 to 10 carbon atoms, aralkyl such as benzyl or phenethyl, phenyl or substituted phenyl. The compounds are useful in photographic applications.Type: GrantFiled: June 11, 1982Date of Patent: June 3, 1986Assignee: Polaroid CorporationInventors: Avinash C. Mehta, George H. Nawn, Lloyd D. Taylor
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Patent number: 4550214Abstract: The present invention relates to vinyl biphenyl compounds of the formula ##STR1## wherein one of R.sup.1 and R.sup.2 is vinyl and the other is hydrogen, and the cyclic moiety A is a -2,5-, -2,3-, or -3,4- di-OR-1-phenyl moiety wherein R is a hydroxy-protecting group, polymers prepared therefrom, and methods of preparation thereof. The subject vinyl biphenyls can be polymerized and the resultant polymers deblocked to remove the R groups and provide the corresponding polymeric dihydroxybiphenyls which can be employed as redox polymers.Type: GrantFiled: October 19, 1983Date of Patent: October 29, 1985Assignee: Polaroid CorporationInventor: Avinash C. Mehta
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Patent number: 4543317Abstract: There is described a photographic system wherein development of an exposed photosensitive element with an aqueous alkaline processing composition is effected in the presence of a compound which is a salt of a radical of a substituted phenylmercaptoazole complexed with a radical of a quaternary. The salts are either insoluble or have extremely low solubility in water and become soluble, and photographically active, in alkaline environment.Type: GrantFiled: December 19, 1984Date of Patent: September 24, 1985Assignee: Polaroid CorporationInventors: Avinash C. Mehta, Lloyd D. Taylor
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Patent number: 4461824Abstract: Polymers comprising recurring units having cyclic .beta.-elimination moieties capable of undergoing .beta.-elimination in an alkaline environment and are disclosed for use in diffusion control layers in diffusion transfer photographic products.Type: GrantFiled: December 29, 1982Date of Patent: July 24, 1984Assignee: Polaroid CorporationInventor: Avinash C. Mehta
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Patent number: 4417064Abstract: The present invention relates to novel biphenyl compounds of the formula ##STR1## wherein one of R.sup.1 and R.sup.2 is hydrogen and the other is --CH.sub.3-m X.sub.m wherein X is chloro or bromo and m is an integer one or two, and the cyclic moiety A is a -2,5-; -2,3-; or -3,4-di-OR-1-phenyl moiety wherein R is a hydroxy-protecting group and to a method of preparing same. The biphenyl compounds are useful as intermediates in preparing redox compounds containing a phenylhydroquinone or phenylcatechol moiety.Type: GrantFiled: October 22, 1981Date of Patent: November 22, 1983Assignee: Polaroid CorporationInventor: Avinash C. Mehta
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Patent number: 4412050Abstract: The present invention relates to vinyl biphenyl compounds of the formula ##STR1## wherein one of R.sup.1 and R.sup.2 is vinyl and the other is hydrogen, and the cyclic moiety A is a -2,5-, -2,3-, or -3,4- di-OR-1-phenyl moiety wherein R is a hydroxy-protecting group, polymers prepared therefrom, and methods of preparation thereof. The subject vinyl biphenyls can be polymerized and the resultant polymers deblocked to remove the R groups and provide the corresponding polymeric dihydroxybiphenyls which can be employed as redox polymers.Type: GrantFiled: January 5, 1981Date of Patent: October 25, 1983Assignee: Polaroid CorporationInventor: Avinash C. Mehta
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Patent number: 4390613Abstract: There is disclosed a diffusion transfer photographic system wherein development of an exposed photosensitive element with an aqueous alkaline processing composition is effected in the presence of a compound represented by the formula ##STR1## wherein X represents the nonmetallic atoms necessary to form a nucleus which completes a 5- or 6-membered heterocyclic moiety on said structure including substituted rings and fused rings; R is H, an alkali metal or a group which is cleavable in a photographic aqueous alkaline processing composition; and R.sub.1 is either a group which has a pKa of from about 7 to about 14 which is ionizable to an anion whereby the silver salt of the mercaptan (resulting from cleavage or ionization of --SR) is rendered more soluble in the pH range within which R.sub.1 is ionized to an anion than it is below that pH range, or a precursor of such a group.Type: GrantFiled: January 5, 1981Date of Patent: June 28, 1983Assignee: Polaroid CorporationInventors: Avinash C. Mehta, George H. Nawn, Lloyd D. Taylor
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Patent number: 4365072Abstract: Biphenyl compounds of the formula ##STR1## wherein one of R.sup.1 and R.sup.2 is hydrogen and the other is --CHO and the cyclic moiety A is a -2,5-; 2,3; or 3,4-di-OR-1-phenyl moiety wherein R is hydrogen or a hydroxy-protecting group are disclosed. The compounds are useful as intermediates in preparing redox compounds containing a phenylhydroquinone or phenylcatechol moiety.Type: GrantFiled: October 22, 1981Date of Patent: December 21, 1982Assignee: Polaroid CorporationInventor: Avinash C. Mehta
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Patent number: 4355092Abstract: There are disclosed novel compounds which are represented by the formula ##STR1## wherein X represents the nonmetallic atoms necessary to form a nucleus which completes a 5- or 6-membered heterocyclic moiety, R is H, an alkali metal or a group which is cleavable in aqueous alkaline medium and Z is H, alkyl having from 1 to 10 carbon atoms, aralkyl such as benzyl or phenethyl, phenyl or substituted phenyl. The compounds are useful in photographic applications.Type: GrantFiled: January 5, 1981Date of Patent: October 19, 1982Assignee: Polaroid CorporationInventors: Avinash C. Mehta, George H. Nawn, Lloyd D. Taylor
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Patent number: 4355101Abstract: Novel compounds which are represented by the formula ##STR1## wherein X represents the nonmetallic atoms necessary to form a nucleus which completes a 5- or 6-membered heterocyclic moiety, R is a group which is cleavable in aqueous alkaline medium and R.sub.1 is either a group which has a pKa of from about 7 to about 14 which is ionizable to an anion and wherein the silver salt of the mercaptan resulting from cleavage of -SR is rendered more soluble in the pH range within which R.sub.1 is ionized to an anion than it is below that pH range or a precursor of such a group. The compounds are useful in photographic applications.Type: GrantFiled: January 5, 1981Date of Patent: October 19, 1982Assignee: Polaroid CorporationInventors: Avinash C. Mehta, George H. Nawn, Lloyd D. Taylor
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Patent number: 4105694Abstract: Trimethylamine acrylimide is prepared by condensing a mixture of 3-chloropropionyl chloride, 3-chloropropionic acid and trimethylhydrazinium p-toluenesulfonate; and then converting the thus-formed intermediate to the trimethylamine acrylimide, including the step of deprotonating with base.Type: GrantFiled: December 22, 1976Date of Patent: August 8, 1978Assignee: Polaroid CorporationInventors: Avinash C. Mehta, Donald O. Rickter, Lloyd D. Taylor
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Patent number: 4016340Abstract: This invention relates to novel polymers containing a plurality of hydroxyl groups having aminimide groups attached thereto through an ether linkage and to methods for attaching said aminimide groups onto said polymers containing a plurality of hydroxyl groups.Type: GrantFiled: August 7, 1975Date of Patent: April 5, 1977Assignee: Polaroid CorporationInventors: Henry S. Kolesinski, Avinash C. Mehta, Lloyd D. Taylor