Classifications

• • G—PHYSICS
  • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
  • G03C—PHOTOSENSITIVE MATERIALS FOR PHOTOGRAPHIC PURPOSES; PHOTOGRAPHIC PROCESSES, e.g. CINE, X-RAY, COLOUR, STEREO-PHOTOGRAPHIC PROCESSES; AUXILIARY PROCESSES IN PHOTOGRAPHY
  • G03C1/00—Photosensitive materials
  • G03C1/005—Silver halide emulsions; Preparation thereof; Physical treatment thereof; Incorporation of additives therein
  • G03C1/04—Silver halide emulsions; Preparation thereof; Physical treatment thereof; Incorporation of additives therein with macromolecular additives; with layer-forming substances
  • G03C1/053—Polymers obtained by reactions involving only carbon-to-carbon unsaturated bonds, e.g. vinyl polymers

Definitions

• This invention relates to useful photographic processes, to novel photographic silver halide compositions, to novel polymers used in said compositions and to elements comprising said compositions.
• this invention relates to light-sensitive compositions comprising a polymer which imparts improved characteristics to photographic silver halide emulsions.
• this invention relates to processes for achieving said characteristics.
• this invention relates to photographic elements comprising a hydrophilic colloid in combination with a water-soluble linear addition polymer.
• this invention relates to photographic elements comprising a hydrophilic colloid in combination with a polymer latex, a water soluble linear addition polymer and dicarboxylic acid esters.
• covering power is generally understood to mean the ratio of the optical density of developed silver to the actual quantity of silver present in the photographic composition.
• the maximum optical density after exposure, processing and drying depends only in part upon the amount of free silver which results from the development process. It also depends upon the manner in which the silver is laid down in the photographic element during processing and the stresses to which it is subjected during drying.
• Photographic silver halide emulsions possessing increased covering power are of considerable interest and are particularly desirable since their use results in an increase in gamma and very often an increase in speed while the silver content is maintained at the same level. While covering power, and therefore silver density, can be thus increased, it is also essential that variations between wet and dry states of the photographic compositions be minimized. For example, it is often the practice for purposes of expedience in the graphic arts to measure contrast and density of wet processed film. If unpredictable and substantial density changes occur in the film United States Patent 0 upon drying, the photographic technician cannot rely upon his initial measurements in order to control contrast and density of the photographic negatives and positives made therefrom.
• a loss in density on drying represents a loss of covering power, i.e., a less efficient utilization of the amount of silver present to achieve practical density.
• polymeric addenda In previous attempts to reduce or eliminate changes in covering power and to stabilize density loss in photographic silver halide emulsions containing a hydrophilic colloid such as gelatin, various polymeric addenda have been described as useful therefor. However, when these polymeric addenda, for example, such as polyacrylamide, poly[N-(2-hydroxyethyl)acrylamide], poly(vinyl pyrrolidone), poly(N-acrylylmorpholine) and the like, are added jointly with other additives such as polymeric latexes, the beneficial effect of the covering power addenda is most often lost or appreciably diminished.
• polymeric latex it will be understood that we mean a colloidal dispersion of a insoluble polymer in an essentially aqueous system.
• polymers such as polyacrylamide are indeed known to increase covering power and inhibit density loss on drying of photographic compositions, their effectiveness seems to be limited either to those compositions which are all gelatin or to those which are combinations of gelatin and synthetic polymer.
• poly(vinyl pyrrolidone) and certain polyvinyl esters of dicarboxylic acids such as succinoylated poly(vinyl alcohol) function in both all-gelatin and gelatin-synthetic polymer combinations but no polymer composition has been described heretofore which achieves the above effects in both all-colloid systems such as gelatin and colloid-polymer combinations without causing a softening of the emulsion coating.
• This invention relates to improving the characteristics of compositions comprising a photographic silver halide and a binder by incorporating in said binder, and in elements comprising said compositions, a N-[tris(hydroxymethyl)methyl] substituted acrylamide polymer having recurring units of the formula ion,
• R is hydrogen, methyl or ethyl.
• the N-substituted acrylamide polymer can be used in any effective concentration, a suitable concentration often being about 3 to about 20 weight percent and preferably about 10 to about 17 weight percent based upon the total weight of the binder present in the photographic composition.
• the improved physical properties of the photographic compositions include increased covering power of developed silver, decreased density loss on drying, decreased dimensional changes and the like. Said improved physical properties are unexpectedly obtained by the presence of only a minor amount, for example, up to about weight percent, based on the Weight of the vehicle or binder in the composition, e.g. a photographic emulsion, of a polymer, e.g. a homoor copolymer having recurring units of Formula I set forth before.
• a significant feature of this invention is a method whereby the presence of said polymer in an effective concentration, for example, up to 20% based upon the emulsion binder in a photographic element containing a lightsensitive silver halide emulsion, affords improved covering power and decreased loss of density upon drying without softening of the emulsion.
• N-[tris(hydroxymethyl)methyl] acrylamide units such as copoly(2-acrylamido-Z-hydroxymethyl-1,3-propanediolacrylamide), copoly(2 acrylamido-Z-hydroxymethyl-1,3- propanediol-N-vinyl pyrrolidone), copoly[2-acrylamido- 2 hydroxymethyl 1,3 propanediol N (2 hydroxyethyl) acrylamide] and the like.
• a homopolymer consisting of recurring units as described above when added to light-sensitive photographic emulsions at a concentration of from about 10 percent to about 17 percent by weight, based on the weight of total binding agent present, imparts the desirable characteristics set forth above to said emulsions.
• These photographic emulsions comprise a light-sensitive material, for example, silver halides such as silver chloride, silver bromide, silver chlorobromide and the like.
• Said emulsions can have a binding agent which is all gelatin, all non-gelatin, gelatin and a soluble extender polymer system or gelatin and latex polymer, or combinations of gelatin, latex and soluble polymers, as set forth herein.
• the admixture component derived from Formula I desirably constitutes at least 30 percent by Weight of said physical admixture.
• copolymers which comprise units of an ethyenically unsaturated monomer, whose homopolymers impart good covering power and reduced density loss on drying in photographic silver halide emulsions, combined with units having Formula I.
• This combination provides not only good covering power and other beneficial photographic properties but also the unexpected and added desirable property of maintaining the hardness of the emulsion coating despite the usual characteristic of the homopolymer to soften the emulsion coating.
• Particularly good results are achieved with said copolymers when the component having Formula I constitutes at least 30 percent by weight of the total weight of said copolymers.
• Said copolymers are advantageously added to photographic silver halide emulsions in a concentration of from 10 to 17 percent by weight based on the total weight of binding agent employed total weight of binding agent employed.
• our normally solid N-(trimethylol methyl) acrylamide polymers are present in various forms such as, for example aqueous solutions which are most conveniently used in emulsion manufacture.
• said improvements in covering power, inhibition of density loss on drying and reduction of softening of the emulsion are imparted to photographic compositions comprising (1) all-colloid binders such as for example, gelatin, (2) non-gelatin binders such as poly (vinyl alcohol) and (3) a binder comprising a mixture of gelatin with a soluble or latex polymeric extender, such as copoly (ethyl acrylate-acrylic acid).
• all-colloid binders such as for example, gelatin
• non-gelatin binders such as poly (vinyl alcohol)
• a binder comprising a mixture of gelatin with a soluble or latex polymeric extender, such as copoly (ethyl acrylate-acrylic acid).
• Copolymers which are suitable for the practice of this invention include those comprising monomeric units of Formula I above with monomeric units derived from other ethylenically, preferably monoethylenically unsaturated polymerizable monomers.
• Such other ethylenically unsaturated monomers are preferably those which form homopolymers which increase covering power when added to a photographic silver halide emulsion, e.g. acrylamide; but which homopolymers tend to soften the emulsion coating, such copolymers effect a marked reduction in softness, but to a large measure, retain the good covering power generally associated with the homopolymer.
• Exemplary of the monomeric N-[tris(hydroxymethyl)methyl]acrylamides useful in preparing said copolymers are 2 acrylamido 2 hydroxymethyl-1,3- propanediol, 2 methacrylamido 2 hydroxymethyl-1,3- propanediol, and the like.
• Examples of ethylenically unsaturated monomers which can be copolymerized with said N-substituted acrylamides are N-(2 hydroxyethyl) acrylamide, acrylamide, vinyl pyrrolidone, and N-acrylylmorpholine.
• mixtures of a poly[N-(tris- (hydroxymethyl)methyl)acrylamide] with polyvinyl half esters of dicarboxylic acids such as those of succinic, maleic, and the like or polymers containing repeating units derived from a vinyl p-hydroxyethylcarbamoylalkylcarbamate are effective in practicing our invention.
• polyvinyl half esters of dicarboxylic acids such as those of succinic, maleic, and the like or polymers containing repeating units derived from a vinyl p-hydroxyethylcarbamoylalkylcarbamate
• succinoylated poly(vinyl alcohol) which is conveniently admixed with poly(2-acrylamido-2 hydroxymethyl 1,3 propanediol).
• photographic silver halide emulsions containing a physical admixture of poly(vinyl ,6 hydroxyethylcarbamoylmethylcarbamate) and poly(2 acrylamido 2 hydroxymethyl 1,3 propanediol) exhibit less emulsion softness than poly(vinyl B hydroxyethylcarbamoylmethylcarbamate) when used alone.
• the temperature at which the homoand copolymers described herein are prepared is subjected to wide variation since this temperature depends upon such variable features as the specific monomer used, duration of heating, pressure employed and like considerations.
• the polymerization temperature generally does not exceed about 100 C., and most often it is in the range of about 50 to about 100 C.
• the polymerization can be carried out in a suitable vehicle, for example, water or mixtures of water with Water miscible solvents, as exempli fied by methanol, ethanol, propanol, isopropyl alcohol, butyl alcohol, and the like.
• the pressure employed in the polymerization is usually only sufficient so as to maintain the reaction mixture in liquid form, al though either superatmospheric or subatmospheric pressures can be used.
• concentration of polymerizable monomer in the polymerization mixture can be varied widely with concentrations up to about 40%, by weight, and preferably about 8 to about 25%, by weight, based on the weight of the vehicle, being satisfactory.
• Suitable catalysts for the polymerization reaction include, for example, the free radical catalysts, such as hydrogen peroxide, cumene hydroperoxide, water soluble azo type initiators and the like. In redox polymerization systems the usual ingredients can be employed. If desired, the polymer can be isolated from the reaction vehicle by freezing, salting out, precipitation or any other procedure suitable for this purpose.
• the blinding agent employed in the silver halide emulsions of the invention can comprise any water-permeable hydrophilic colloid commonly employed and/or combinations thereof. These include, for example, gelatin, colloidal albumin, polysaccharides, cellulose derivatives, synthetic resins such as polyvinyl compounds, including poly(vinyl alcohol) derivatives, acrylamide polymers and the like.
• the water-soluble polymeric additives used in our invention have also been found to be effective when the vehicle or blinding agent contains, in addition to the water-permeable, hydrophilic colloids aforementioned, still other colloids such as water insoluble polymer latexes for example dispersed polymerized vinyl compounds, particularly those which increase the dimensional stability of photographic materials.
• Suitable copolymers which can be used as partial substitute binding agents according to this invention are acrylic copolymers, i.e., those copolymers prepared from polymerizable acrylic monomers containing the characteristic acrylic group,
• Such polymers are conveniently prepared, for example, by the copolymerization of an acrylic monomer with at least one dissimilar monomer which can be another acrylic monomer or some other different polymerizable ethylenically unsaturated monomer.
• the acrylic copolymers employed as gelatin substitutes in the practice of this invention are compatible with hydrophilic colloids such as gelatin itself and have a T of less than about 20 C.
• T can be calculated by differential thermal analysis as disclosed in Techniques and Methods of Polymer Evaluation, volume 1, Marcel Dekker Inc., New York, 1966.
• T is understood. to be a time dependent, kinetic phenomenon represented by a transition temperature at which substantial segmental mobility of the copolymer structure is achieved.
• the temperature at which the thermodynamic characteristics are assumed by the copolymers particularly useful in our invention, within a given time has been found to be not more than about 20 C.
• preferred copolymer binding agents which can be used in this invention comprise units of an alkyl acrylate such as, for example, methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylates (e.g., n-butyl or t-butyl acrylates), amyl acrylates, hexyl acrylates and the like.
• alkyl acrylate such as, for example, methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylates (e.g., n-butyl or t-butyl acrylates), amyl acrylates, hexyl acrylates and the like.
• acrylic copolymers containing units of acrylic acid or a sulfoester acrylate are especially useful in the process.
• Typical polymers of this type are copoly(butylacrylat-e-acrylic acid), copoly- (methyl acrylate-acrylic acid), copoly(ethyl acrylateacrylic acid), copoly(butyl acrylate-3-acryloyloxy-propane-l-sulfonic acid, sodium salt) and the like, as disclosed in Dykstra US. Pat. 3,411,911 issued Nov. 19, 1968.
• the copolymer comprises up to about 30 percent by weight of acrylic acid, a sulfonic acid acrylate or the sulfoester acrylate; especially good results are obtained with latex alkyl acrylate copolymers having up to about 30 percent, by weight, of the acrylic acid or the sulfoester acrylate.
• High ratios of solubilizing groups, such as the acrylic acid groups or the sulfoester groups produce a more soluble solution type polymer with respect to water carrier solvents.
• physical admixtures of the more soluble solution-type polymers and the latex polymers can also be used effectively within the scope of this invention to achieve the desired emulsion characteristics.
• the abovementioned copolymeric binding agents contain units of a third monomer.
• the synthetic polymers comprise units of (1) alkyl acrylates, (2) acrylic acid or sulfoester acrylates, and (3) an acrylic monomer unit having an active methylene group in a side chain such as, for example, in a malonic ester group, an acetoacetic ester group, a cyanoacetic ester group of 1,3-diketone groups as disclosed in Smith Belgian Pat. 712,829 issued Apr. 30, 1968.
• Typical polymers of this class include copoly(ethyl acrylate-acrylic acid-2-acetoacetoxyethyl methacrylate), copoly(butyl acrylate-sodium 3-acryloyloxypropane-1-sulfonate-2-acetoacetoxyethyl methacrylate), copoly(methyl acrylate-sodium acryloyloxypropanesulfonate-Z-acetoacetoxyethyl methacrylate), copoly(butyl acrylate-acrylic acid-Z-cyanoacetoxyethyl methacrylate) and the like and mixtures thereof.
• the copolymers of (1) alkyl aerylates and (2) acrylic acid or the sulfoester can also contain units of (3) sulfobetaines, N-methacryloyl- N-glycylhydrazine hydrochlorides, 2-[2-methacryloyloxyethyl] isothiuronium methanesulfonate and the like.
• Typical copolymers having sulfobetaine units include copoly (butyl acrylate-acrylic acid-4,4,9-trimethyl-8-oxo-7-oxa-4- azonia-9-decene-l-sulfonate) and the like.
• Useful gelatin substitutes are, therefore, copoly mers of the acrylates, methacrylates and sulfoesters as described above, with other polymerizable monomers comprising an ethylenically unsaturated moiety which form water insoluble addition polymers such as vinyl esters, amides, nitriles, ketones, halides, ethers, otB-UIlSfllUIEIEBCl acids or esters thereof, olefins, diolefins and the like, as exemplified by acrylonitrile, methacrylonitrile, styrene, u-methylstyrene, vinyl chloride, vinylidene chloride, methyl vinyl ketone, vinyl acetate, fumaric, maleic and itaconic esters, 2-chloroethyl vinyl ether, methylenemalonitrile, acrylic acid, methacrylic acid, dimethylaminoethyl methacrylate, N-yin
• the nature of the different polymerizable, ethylenically unsaturated compound which is copolymerized with the acrylates, methacrylates and sulfoesters to form the gelatin substitute is subject to wide variation.
• the copolymers used in this invention can contain from about to about 20%, by weight, of such additional monomer, in polymerized form.
• the copolymers employed in the practice of this invention have a molecular weight in the range of about 5,000 to about 500,000 or more.
• those copolymers comprising the recurring units as shown hereinbefore in Formula I exhibit an inherent viscosity in water in a range of from about 0.08 to 0.6 and preferably in a range of from about 0.15 to about 0.5 at a concentration of 0.25 g. per 100 ml. of solution.
• novel compositions and emulsions of the invention can be made in various ways.
• a lightsensitive silver halide or mixture of such halides is precipitated in an aqueous binding agent solution.
• To the precipitated silver halide emulsion which can be washed in any known way, can be added other emulsion adjuvants, and the emulsion then digested.
• To the thus digested emulsion is added an aqueous solution of the polymeric compounds or physical mixtures used in practicing this invention; when a uniform mixture has been obtained, the resulting emulsion can be coated onto a suitable support.
• the photographic compositions of the invention can be coated on a wide variety of supports.
• Typical supports include polymeric films such as cellulose acetate film, polyvinyl acetal film, polystyrene film, polypropylene film and other polyolefin film, polycarbonate films, polyethylene terephthalate film and other polyester film as well as glass, paper, wood and the like.
• Supports such as paper, which are coated with alpha-olefin polymers, particularly polymers of alpha-olefins containing 210 carbon atoms as exemplified by polyethylene, polypropylene and ethylenebutene copolymers and the like, can also be employed.
• emulsions of this invention which contain the polymer additives disclosed herein can be chemically sensitized with compounds of the sulfur group, noble metal salts such as gold salts, reduction sensitized with reducing agents, and combinations of these.
• emulsion layers and other layers present in photographic elements made according to this invention can be hardened with any suitable hardener such as aldehyde hardeners, aziridine hardeners, hardeners which are derivatives of dioxane, oxypolysaccharides such as oxystarch, oxy plant gums, vinylsulfonyl ethers, and the like.
• the emulsions can also contain additional additives, particularly those known to be beneficial in photographic emulsions, including, for example, stabilizers for antifoggants, particularly the watersoluble inorganic acid salts of cadmium, cobalt, manganese, and zinc as disclosed in U.S. Pat. 2,839,405 of Jones issued June 17, 195 8, the substituted triazaindolizines as disclosed in U.S. Pats. 2,444,605 of Heimbach and Kelly issued July 6, 1948, and 2,444,607 of Heimbach issued July 6, 1948, speed-increasing materials, plasticizers and the like.
• stabilizers for antifoggants particularly the watersoluble inorganic acid salts of cadmium, cobalt, manganese, and zinc as disclosed in U.S. Pat. 2,839,405 of Jones issued June 17, 195 8
• the substituted triazaindolizines as disclosed in U.S. Pats. 2,444,605 of Heimbach and Kelly issued July 6, 1948, and
• these emulsions can be used in X-ray and other non-optically senstized systems and in ortho chromatic, panchromatic and infrared sensitive systems.
• the sensitizing addenda can be added to photographic systems before or after any sensitizing dyes which are used.
• Some sensitizers which give particularly good results in the photographic compositions disclosed herein are the alkylene oxide polymers which can be employed alone or in combination with other materials, such as quaternary ammonium salts, as disclosed in U.S. Pat. 2,886,437 of Piper issued May 12, 1959, or with mercury compounds and nitrogen-containing compounds, as disclosed in U.S. Pat 2,751,299 of Carroll issued June 19, 1956.
• EXAMPLE 1 In a three-liter flask fitted with a thermometer, stirrer and dropping funnel are placed 1.6 liters of water and 1012 g. (8.36 mols) of 2-amino-2-hydroxymethyl-1,3- propanediol. The internal temperature is brought to 0 C. by external cooling. To this solution is added dropwise 322 ml. (4.18 mols) of acrylyl chloride at such a rate that the internal temperature never exceeds 5 C. During the entire addition, the reaction mixture is vigorously stirred.
• N-hydroxymethylacrylamide is synthesized from acrylamide and formaldehyde as described by H. Technosiedler and P. Adams, US. Pat. 2,864,861. Recrystallization from methylene chloride and then from s-dichloroethane gives material of M.P. 72.5-7 5 C.
• EXAMPLE 6 To 1.2 liters of a water-isopropanol solution (70/30 'by volume) is added 300 g. of Z-acrylamido-Z-hydroxymethyl-1,3-propanediol, prepared according to the procedure of Example 1. To this solution is added 5 ml. of a 35 percent hydrogen peroxide solution and the resulting mixture is placed in a constant temperature bath at 90 C. under a reflux condenser.
• EXAMPLE 7 To 600 ml. of a water-isopropanol solution (70/30 by volume) are added 55.0 g. Z-methacrylamido-Z-hydroxymethyl-l,3-propanediol, prepared as in Example 3, and 0.5 ml. of a 35 percent hydrogen peroxide solution. The resulting solution is refluxed overnight on a steam bath and then concentrated to one-half volume under reduced pressure. The polymer is precipitated by pouring the clear aqueous dope into acetone with stirring. The material is washed twice with changes of fresh acetone, filtered, and dried in a vacuum oven at 60 C. 33.6 grams of dry polymer, poly(2-methacrylamido-2-hydroxymethyl- 1,3-propanediol), is obtained. The inherent viscosity in water is 0.11.
• EXAMPLE 8 The procedure of Example 6 is used to prepare poly(1- acrylamido 1 hydroxymethylpropane), poly[N (2 hydroxyethyl)acrylamide] and poly(N-hydroxymethylamide). In each instance an equivalent amount of their respective monomers-Le. l-acrylamido-l-hydroxymethylpropane, N-(2-hydroxyethyl) acrylamide and N-hydroxymethylacrylamide are substituted for the 2-acrylamido-2- hydroxymethyl-1,3-propanediol employed in Example 6.
• EXAMPLE 9 Into a 1 liter round bottom flask fitted with a condenser are placed 820 ml. of a solution composed of 70 parts water and 30 parts isopropanol (by volume), 100 g. (0.57 mole) of 2-acrylamido-Z-hydroxymethyl-1,3-propanediol prepared as in Example 1 and 39.9 g. (0.57 mole) 10 of acrylamide. To this solution is added 2.8 ml. of a 35 percent hydrogen peroxide solution and the resulting mixture is placed in a constant temperature bath at C.
• the polymer is washed twice with fresh changes of acetone, filtered and dried under reduced pressure at 60 to give 42 g. of copoly(Z-acrylamido-Z-hydroxymethyl-1,3-propanediol; N-vinyl pyrrolidone) with an inherent viscosity of 0.15 in water.
• EXAMPLE 1 1 Into a 200 ml. flask fitted with a reflux condenser are placed 44 ml. of a water-isopropyl alcohol solution (1:1 by volume), 17.5 g. of 2-acrylamido-2hydroxymethyl- 1,3-propanediol, prepared as in Example 1, 11.5 g. of N-(Z-hydroxyethyl)acrylamide, prepared as in Example 4, dissolved in ml. of water-isopropyl alcohol, and 0.50 ml. of a 35 percent hydrogen peroxide solution. The resulting solution is refluxed on a steam bath for 2 hours.
• the dope is cooled to room temperature and poured into 4 liters of stirred acetone to precipitate the polymer.
• the solid, copoly[2-acrylamido-2-hydroxymethyl-1,3-propanediol; N-(Z-hydroxymethyl)acrylamide] is washed several times in fresh changes of acetone, filtered, and dried under a constantly applied vacuum.
• EXAMPLE 12 Three separate medium speed silver bromoiodide gelatin negative emulsions are prepared and coated onto three photographic compositions (I, IV and VI). Each portion is coated separately on a polyester support at 450 mg./ft. silver and 1248 mg./ft. gelatin. Additional coatings are identically made except that, before coating, the following polymers are added:
• Coating II 50 g./ silver mole of polyac1ylamide.
• Coating III 50 g./silver mole of poly(2-acrylamido-Z-hydroxymethyl-1,3- propanediol).
• Samples of each of these coated films are exposed in an Eastman IB Sensitometer, developed for 5 min. in Kodak DK-50 developer, fixed, washed and dried. The densities of the sensitometric strips are measured both before and after drying. The density change on drying is measured at a Wet density of 1.6..
• Samples of the films are also tested for softening of the emulsion coating. This measurement is made on the wet coating after each step of processing at 68 F. for 5 min. in Kodak developer DK-50, in fix and in water.
• the values listed in Table I represent the weight load of 1 1 a stylus under which each coating is subjected before the emulsion becomes ploughed. The hard coating, therefore, is indicated by the high figure.
• EXAMPLE 13 Two separate control coatings (I and IV) are prepared and used in a gelatin-latex binding agent combination comprising a medium speed silver bromoiodide gelatin negative emulsion containing a butyl acrylate-acrylic acid-sulfo ester polymer latex. Each portion is then coated separately on a polyester support at 450 mg./ft. silver, 832 mg./ft. gelatin and 415 mg./ft. latex. Additional coatngs are made identically except that before coating the following polymers are added:
• Coating II 50 g./slver mole of polyacrylamde.
• Coating III 50 g./ silver mols of poly[2-acrylamido- 2-hydr0methyl-1,3-propanedol] 50 g./silver mole of poly(N-hydroxymethylacrylamide)
• the latex polymer is prepared by the procedure of Example 5 of Dykstra US. Pat. 3,411,911 issued Nov. 19, 1968, referred to hereinbefore, except that an equivalent amount of butyl acrylate is substituted for the methyl acrylate in the example.
• the coatings are exposed and processed and the photographic properties and softness values determined in the Coating V
• Table II demonstrate that in me gelatinlatex system all of the polymers improve covering power and, further, that poly(2-acrylamido-Z-hydroxymethyl- 1,3-propanediol) does not cause density loss on drying.
• the unique characteristic of poly(Z-acrylamido-Z-hydroxymethyl-1,3-propanediol) is that is imparts desirable photographic properties without softening the gelatin-latex coatings in contrast to other polymers.
• a medium speed silver bromoiodide negative emulsion employing a combination of gelatin and butyl acrylateacrylic acid-sulfoester polymeric latex as the vehicle is prepared and coated (Coating I) on a polyester support at 450 mg. silver per sq. ft., 832 mg. gelatin per sq. ft. and 415 mg. polymeric latex per sq. ft.
• Coating II An additional coating (Coating II) is made in the identical manner as Coat- 14 ings (Coatings III and IV) are made identically as Coating I except that before coating poly(2-acrylamide-2-hydroxymethyl-1,3-propaniol) is added as follows.
• homopolymers which improve covering power and reduce density loss on drying in photographic silver halide emulsions with attendant unwanted softening of the emulsion coating may be advantageously physically mixed with a poly[N-(trishydroxymethyl)methyl acrylamide] in practicing this invention.
• the resulting-admixture retains in large degree the desirable photographic properties of the individual components while exhibiting considerably less softness than the admixed homopolymer by itself. Typical results obtained in testing such admixshown in Table IV. tures are presented in Examples 17 through 21.
• EXAMPLE 1 6 e es yl mi reta e ma e e TWO h i Samples of polyacrylamide and poly(2-acrylan1ido-2- hydroxymethyl 1,3 propanediol) are added to separate portions of a medium speed silver bromoiodide gelatin negative emulsion at concentrations of 50 g. and 30 g. per mole of silver respectively. Similarly, physical mixtures of these polymers in which the weight of polyacrylamide is varied are added to separate portions of the above-described emulsion. Each sample of physical mixture is incorporated in the emulsion at 30 g. per mole of silver. The variations in weight percent of polyacrylamide are given in Table VI below. Each emulsion sample is coated on a poly(ethylene terephthalate) film support at a coverage of 450 mg. of silver per sq. ft. and 1248 g.
• EXAMPLE 18 for screen X-ray materials and containing 110 g. of gelatin per mole of silver.
• Each emulsion sample is coated on a poly(ethylene terephthalate) film support at a coverage of 473 mg. of silver per sq. ft. and 480 mg. of gelatin per sq. ft. All of the coatings are exposed and processed according to the procedure of Barnes and Rees, Belgian Pat. 700,301, issued Aug. 31, 1967. The sensitometric results and softness values are shown in Table VIII.
• Samples of polyacrylamide and poly(2-acrylamido-2- hydroxymethyl-1,3-propanediol) and physical mixtures of equal parts by weight of each of these compounds are rays materials used in combination with intensifying screens.
• each samg the copolymenc addenda Show contains 25 grams per mole of Silver of po1y(2 aCryl higher softness values for both gelatin and gelatin-latex amido-2-hydroxymethyl 1,3 propanediol) and 25 gram emulsions, Whereas the samples of these emulsions which per mole of silver of homopolymer.
• the test results are Contaln polyacrylamlde exhlblt Covermg P along with given in Table IX. unwanted emulsion softening.
• Example 20 The procedure of Example 20 is repeated except that the gelatin is replaced by the combination of gelatin and Samples of 2 acrylamrdo-Z-hydroxymethyl-1,3-prolatex polymer used in Example 15. The results are set panediol copolymerized with acrylarnide, N vinylpyr. forthinTable X.
• a composition comprising a photographic silver hydroxymethyl 1,3 propanediol with a polymerizable halide and a binder comprising a polymer av g l Cu monomer comprising an ethylenically unsaturated moiety. ring units of the formula 19.
• a process for increasing the covering power and R reducing density loss on drying of a photographic silver I l halide composition which comprises incorporating in said 2 Q.
• L composition a polymer having recurrmg units of the 3 formula R HNO(CH;OH)3 where R is hydrogen, methyl or ethyl. l l 2.
• a photographic element comprising the composi- L l tion of claim 1. 0:0
• polymer is a copolyrner of 2-acrylamido-2-hydroxymeth- 20.
• the process of claim 19 in which said polymer yl-1,3-propaned1ol with acrylamide, N-VIIIYlPYIIOlldOIlG comprises recuring units of Z-acrylamido 2 hydroxyy y y acfylamldemethyl 1,3 propanediol and is admixed with another 5.
• the photographlc element of claim 4 in which the l blnder COIIIPIISCS l 21.
• the process of claim 20 in which said other T ph t p element of 61mm 4 111 WhlCh the polymer is a polyvinyl ester of a dicarboxylic acid. blndel" COIIIPFISBS a -p y f 6O 22.
• the process of claim 21 in Which said polyvinyl
• the Photographlc element of clalm 6 In Whlch 531d ester of the dicarboxylic acid is succinoylated poly(vinyl element comprises a coarse grain silver halide. 1 h 1) 8.
• a photographic element according to claim 2 in Refeyences Cited which said binder comprises a hydrophilic colloid.
• a composition according to claim 1 in which said 65 UNITED STATES PATENTS binder comprises the polymer of claim 1 in a concentra- 3,178,296 4/ 1965 sk et a1- 961 14 tion of about 3 to about 20 percent, by weight, of total binden NORMAN G.
• TORCHIN, Primary Examiner 10 The element of claim 8 in which said colloid E, C KIMLIN A i ta tE a i comprises gelatin.

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Cited By (4)

• 1969
  • 1969-04-02 US US812882A patent/US3591387A/en not_active Expired - Lifetime
• 1970
  • 1970-03-04 CA CA076460A patent/CA938154A/en not_active Expired
  • 1970-03-26 GB GB04873/70A patent/GB1278721A/en not_active Expired
  • 1970-03-31 BE BE748266D patent/BE748266A/xx unknown
  • 1970-04-01 JP JP45027349A patent/JPS4926133B1/ja active Pending
  • 1970-04-01 FR FR7011585A patent/FR2042746A5/fr not_active Expired
  • 1970-04-01 DE DE19702015525 patent/DE2015525A1/de active Pending

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