Patents by Inventor Pranab Bagchi
Pranab Bagchi 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: 5395748Abstract: An inexpensive, ballasted optical brightener for use in photographic elements is prepared by reacting an optical brightener of the formula ##STR1## where M is a cation; X is a group capable of undergoing nucleophilic displacement; and Z is ##STR2## or --O--R.sub.3, where each of R1 and R2 is a hydrogen atom, or an aromatic group which can be unsubstituted or substituted with one or more groups unreactive towards X; and R3 is an aromatic group which can be unsubstituted or substituted with one or more groups unreactive towards Xwith a water soluble polymer, such as gelatin. The resulting ballasted optical brightener is stable in aqueous photographic compositions.Type: GrantFiled: December 8, 1993Date of Patent: March 7, 1995Assignee: Eastman Kodak CompanyInventors: Anthony Adin, Pranab Bagchi
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Patent number: 5393650Abstract: This invention describes the use of surfactants of the following types:Type A--Surfactant comprising 6 to 22 carbon atom hydrophobic tail with one or more attached hydrophilic chains comprising at least 8 oxyethylene and/or glycidyl ether groups that may or may not be terminated with a negative charge such as a sulfate group.Type B--Block oligomeric surfactants comprising hydrophobic polyoxypropylene blocks (A) and hydrophilic polyoxyethylene blocks (B) joined in the manner of A--B--A, B--A--B, A--B, (A--B.sub.n .tbd.G.tbd.(B--A).sub.n, or (B--A).sub.n .tbd.G(A--B).sub.n, where G is a connective organic moiety and n is between 1 and 3.Type C--Sugar surfactants, comprising between one to three 6 to 22 carbon atom hydrophobic tail with one or more attached hydrophilic mono or oligosaccharidic chains that may or may not be terminated by a negatively charged group such as a sulfate group.Type: GrantFiled: June 27, 1994Date of Patent: February 28, 1995Assignee: Eastman Kodak CompanyInventors: Pranab Bagchi, Melvin M. Kestner
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Patent number: 5385812Abstract: The invention discloses a continuous method of manufacture of gelled dispersion melts of "small-particle" microprecipitated photographic agents. The continuous melt manufacturing process of this invention provides dispersion melts that are invariant in agent concentration, melt viscosity, and turbidity as a function of the run time and are also very reproducible and robust in repetitive preparations. Many photographic melts of this invention exhibit high photographic activity and light stability of the agents when exposed to light.Type: GrantFiled: December 28, 1992Date of Patent: January 31, 1995Assignee: Eastman Kodak CompanyInventors: Pranab Bagchi, James T. Beck, Vincent J. Flow, III
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Patent number: 5378598Abstract: The invention provides a method of nucleating silver halide particles wherein said nucleation is carried out in the presence of acid processed ossein (APO) gelatin or chain-extended acid processed ossein (CE-APO) gelatin and the composition formed therefrom.Type: GrantFiled: December 21, 1992Date of Patent: January 3, 1995Assignee: Eastman Kodak CompanyInventors: Pranab Bagchi, Melvin D. Sterman, Jacob I. Cohen
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Patent number: 5370966Abstract: The invention discloses an aqueous-developable chromogenic photographic heat-transferable non-aqueous dye-diffusion-transfer photographic element comprising radiation sensitive silver halide, a dye-providing compound that forms or releases a heat-transferable, image dye upon reaction of said compound with the oxidation product of a primary amine developing agent, a hydrophilic binder, and a thermal solvent for facilitating non-aqueous diffusion transfer wherein said thermal solvent comprises a sugar group containing amphiphilic compound, said amphiphilic compound comprising from one to three independently constituted 3 to 22 carbon atom hydrophobic tail(s) with one or more attached hydrophilic mono or oligosaccaridic rings or chains such that the HLB value of the compound is less than about 13.Type: GrantFiled: November 29, 1993Date of Patent: December 6, 1994Assignee: Eastman Kodak CompanyInventors: Pranab Bagchi, David S. Bailey
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Patent number: 5366842Abstract: The invention creates a selective oxygen barrier around individual coupler or other photographically active particles by surrounding each particle with a layer of water applicable oxygen barrier polymer such as polyvinyl alcohol (PVA), which will also act as a steric barrier to coalescence of the particles. Photographic products formed with such materials are more dye stable.Type: GrantFiled: July 23, 1993Date of Patent: November 22, 1994Assignee: Eastman Kodak CompanyInventors: Pranab Bagchi, James L. Edwards, Wendell F. Smith, Jr., Brian Thomas
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Patent number: 5358831Abstract: This invention provides composition and method to overcome the very high viscosity of prior small-particle dispersions when admixed with gelatin in aqueous solution for coating a photographic film element.The invention is generally accomplished by the utilization of a second surfactant in the melt formulated by the admixture of the small-particle dispersion and the gelatin solution. The surfactants of this invention, that is, utilized to control the theology of such said melts, have the following general structure: ##STR1## wherein n=5 to 20 andx=1 to 4.Type: GrantFiled: December 13, 1990Date of Patent: October 25, 1994Assignee: Eastman Kodak companyInventors: Pranab Bagchi, James L. Edwards, Danuta Gibson, Thomas A. Rosiek, Brian Thomas, Vincent J. Flow, III
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Patent number: 5318889Abstract: This invention describes the advantages associated with the use of chain-extended acid processed ossein gelatin as the makeup gelatin, with emulsion precipitated in lime-processed ossein gelatin. Such photographic elements show a definite speed-fog advantage, compared to systems where standard lime-processed ossein gelatin is used solely.Type: GrantFiled: December 21, 1992Date of Patent: June 7, 1994Assignee: Eastman Kodak CompanyInventors: Pranab Bagchi, Melvin Sterman, Jacob Cohen
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Patent number: 5300418Abstract: The invention relates to a melt for the coating of a layer in a photographic element and which contains water, gelatin and an anionically charged, hydrophobic group containing compound that is (a) water soluble or soluble in a solution of 5 to 20 percent of water miscible organic solvent,said melt being further characterized by containing an amount of an amphiphilic compound which is sufficient to reduce the viscosity of said melt, said compound selected from the class consisting of:Type A: Sugar (saccharidic) compounds, characterized by having one to three hydrophobic groups, each group containing from about 6 to about 22 carbon atoms, and having one or more attached hydrophilic mono- or oligosaccharidic hydrophilic chains that may or may not be terminated by a negatively charged group such as a sulfate, sulfonate or a carboxyl group; andType B: Compounds compromising a hydrophobic group having from about 6 to about 22 carbon atoms and having one or two attached hydrophilic chains comprising at least 4 oxyetType: GrantFiled: April 16, 1992Date of Patent: April 5, 1994Assignee: Eastman Kodak CompanyInventors: Gary W. Visconte, Pranab Bagchi, James A. Friday, Michael W. Orem, Alan R. Pitt
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Patent number: 5279931Abstract: This invention describes a process of coprecipitating a photographic material such as a dye-forming coupler inside a base ionizable polymeric particle. Preparation of such a dispersion is performed by providing a first flow comprising a solution of a surfactant in water containing a polymer ionizable by base, providing a second flow comprising a water miscible solvent, base, water, and the photographic material, then mixing the said first and said second flow and immediately neutralizing the mixed flow to precipitate the photographic material inside the polymer particles forming a fine particle colloidal dispersion of the photographic material. The polymer dispersions of the invention are characterized by high photographic activity and high dye-stability in some cases.Type: GrantFiled: April 26, 1991Date of Patent: January 18, 1994Assignee: Eastman Kodak CompanyInventors: Pranab Bagchi, Steven J. Sargeant, James T. Beck, Brian Thomas
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Patent number: 5264317Abstract: The invention creates a selective oxygen barrier around individual coupler or other photographically active particles by surrounding each particle with a layer of water applicable oxygen barrier polymer such as polyvinyl alcohol (PVA), which will also act as a steric barrier to coalescence of the particles. Photographic products formed with such materials are more dye stable.Type: GrantFiled: November 12, 1992Date of Patent: November 23, 1993Assignee: Eastman Kodak CompanyInventors: Pranab Bagchi, James L. Edwards, Wendell F. Smith, Jr., Brian Thomas
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Patent number: 5252425Abstract: This invention relates to a full-color hard copy imaging system and a process, where a multiply photosensitive donor sheet, comprising clear polymeric or an opaque paper base, coated sequentially with a first layer of patches of a cyan, a magenta, and a yellow dye, that are thermally diffusible, with a second layer also coated sequentially with patches of a red light sensitive, a green light sensitive or a blue light sensitive, negative or a positive working photoresist layer, in such a manner that each of the colored dye patches are in registry with their complementary color sensitive photoresist patches, is exposed with white light sequentially, three times in registry on the three primary light sensitive patches, through a multicolor image (a positive transparency or a photographic negative), to produce crosslinks, image wise, in the exposed areas in the case of the negative resist system, or to uncrosslink the resist structure image wise in the exposed areas for a positive working resist system.Type: GrantFiled: August 19, 1991Date of Patent: October 12, 1993Assignee: Eastman Kodak CompanyInventor: Pranab Bagchi
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Patent number: 5248558Abstract: It has been shown by Photon Correlation Spectroscopy than when additional hardener is added to below saturation gel-grafted polymer particles, the gel layer shrinks due to hardening, as there is no free gel left in solution. In films, such case-hardened gelatin-grafted soft polymer particles can act as highly elastic stress absorbing fillers. This is because the dry case-hardened shell is expected to form a thin hard shell around the soft polymer particles. It is shown that gelatin-grafted soft polymer particles and case-hardened gelatin-grafted soft polymer particles, incorporated in the emulsion layers of pressure sensitive photographic products, produce coatings with highly reduced pressure sensitivity without any developability or delamination concerns. In this invention the case-hardened gelatin-grafted polymer particles are preferred over the simple gelatin-grafted material. The core polymer particle can have diameters anywhere between 10 to 10.sup.Type: GrantFiled: June 20, 1991Date of Patent: September 28, 1993Assignee: Eastman Kodak CompanyInventors: Pranab Bagchi, William L. Gardner
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Patent number: 5185230Abstract: The invention creates a selective oxygen barrier around individual coupler or other photographically active particles by surrounding each particle with a layer of water applicable oxygen barrier polymer such as polyvinyl alcohol (PVA), which will also act as a steric barrier to coalescence of the particles. Photographic products formed with such materials are more dye stable.Type: GrantFiled: September 3, 1991Date of Patent: February 9, 1993Assignee: Eastman Kodak CompanyInventors: Pranab Bagchi, James L. Edwards, Wendell F. Smith, Jr., Brian Thomas
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Patent number: 5182189Abstract: Base and auxiliary solvent solubilized precipitated dispersions of couplers and other photographic materials usually produce very small particle dispersions, and usually such dispersions are extremely highly reactive because of the smallness of the particle size. However, some relatively more hydrophobic couplers, even through they produce small particles when a dispersion if formed by the precipitation technique, lead to extremely unreactive dispersions. The method of this invention constitutes a single step coprecipitation technique where a base deprotonation compound, preferably a liquid carboxylic acid, is incorporated into the precipitated particles to produce photographically highly active coupler dispersions.Type: GrantFiled: October 11, 1991Date of Patent: January 26, 1993Assignee: Eastman Kodak CompanyInventors: Pranab Bagchi, Steven J. Sargeant
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Patent number: 5158863Abstract: The invention is performed by providing a first flow of water and surfactant, a second flow comprising solvent, base and photographic material, and mixing said first and second streams and either simultaneously or immediately following thereof neutralizing said streams to prevent hydrolysis of a hydrolyzable surfactant and/or premature precipitation of particles before neutralization. The streams then may be immediately treated for formation into photographic materials. In a preferred method the first and second stream may be brought together immediately prior to a mixer with addition of acid directly into the mixer to neutralize the dispersion of fine particles.Type: GrantFiled: February 1, 1991Date of Patent: October 27, 1992Assignee: Eastman Kodak CompanyInventors: Pranab Bagchi, James T. Beck, Lia A. Crede
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Patent number: 5135844Abstract: The invention is generally accomplished by utilization of a surfactant for very small particle photographic dispersions. Three types of such surfactants that have been identified are as follows:Type A--Surfactant comprising 6 to 22 carbon atom hydrophobic tail with one or more attached hydrophilic chains comprising at least 8 oxyethylene and/or glycedyl ether groups that may or may not be terminated with a negative charge such as a sulfate group.Type B--Block oligomeric surfactants comprising hydrophobic polyoxypropylene blocks (A) and hydrophilic polyoxyethylene blocks (B) joined in the manner of A--B--A, B--A--B, A--B, (A--B).sub.n .tbd.G.tbd.(B--A), or (B--A).sub.n .tbd.G.tbd.(A--B).sub.n, where G is a connective organic moiety and n is between 1 and 3.Type C--Sugar surfactants, comprising between one to three 6 to 22 carbon atom hydrophobic tail with one or more attached hydrophilic mono or oligosaccharidic chains that may or may not be terminated by a negatively charged group such as a sulfate group.Type: GrantFiled: February 12, 1991Date of Patent: August 4, 1992Assignee: Eastman Kodak CompanyInventors: Pranab Bagchi, Gary J. McSweeney, Steven J. Sargeant
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Patent number: 5104776Abstract: Base and auxiliary solvent solubilized precipitated dispersions of couplers and other photographic materials usually produce very small particle dispersions, and usually such dispersions are extremely highly reactive because of the smallness of the particle size. However, some relatively more hydrophobic couplers, even though they produce small particles when a dispersion is formed by the precipitation technique, lead to extremely unreactive dispersions. The method of this invention constitutes a single step coprecipitation technique where a base deprotonation compound, preferably a liquid carboxylic acid, is incorporated into the precipitated particles to produce photographically highly active coupler dispersions.Type: GrantFiled: November 29, 1989Date of Patent: April 14, 1992Assignee: Eastman Kodak CompanyInventors: Pranab Bagchi, Steven J. Sargeant
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Patent number: 5091296Abstract: This invention describes a process of coprecipitating a photographic material such as a dye-forming coupler inside a base ionizable polymeric particle. Preparation of such a dispersion is performed by providing a first flow comprising a solution of a surfactant in water containing a polymer ionizable by base, providing a second flow comprising a water miscible solvent, base, water, and the photographic material, then mixing the said first and said second flow and immediately neutralizing the mixed flow to precipitate the photographic material inside the polymer particles forming a fine particle colloidal dispersion of the photographic material. The polymer dispersions of the invention are characterized by high photographic activity and high dye-stability in some cases.Type: GrantFiled: June 26, 1990Date of Patent: February 25, 1992Assignee: Eastman Kodak CompanyInventors: Pranab Bagchi, Steven J. Sargeant, James T. Beck, Brian Thomas
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Patent number: 5089380Abstract: Base and auxiliary solvent solubilized precipitated dispersions of couplers and other photographic materials usually produce very small particle dispersions, and usually such dispersions are extremely highly reactive because of the smallness of the particle size. However, some relatively more hydrophobic couplers, even though they produce small particles when a dispersion is formed by the precipitation technique, lead to extremely unreactive dispersions. The method of this invention constitutes a single step precipitation technique where a permanent high boiling water insoluble coupler solvent is incorporated into the precipitated particles to produce photographically highly active coupler dispersions.Type: GrantFiled: August 23, 1990Date of Patent: February 18, 1992Assignee: Eastman Kodak CompanyInventor: Pranab Bagchi