US3647459A - Novel photographic elements and means for rapid processing of photographic elements - Google Patents

Abstract

A photographic element comprising an acrylic interpolymer can be rapidly processed at high temperatures to provide an image record exhibiting reduced haze and improved photographic properties. The acrylic interpolymer contained in the photographic element is compatible with gelatin and has a Tg of less than 20* C. In another aspect of this invention, a photographic element comprising an acrylic interpolymer and a development modifier exhibit improved photographic properties.

Description

United States Patent Taber et al.

[ Mar. 7, 1972 [54] NOVEL PHOTOGRAPHIC ELEMENTS AND MEANS FOR RAPID PROCESSING OF PHOTOGRAPHIC ELEMENTS [72] Inventors: Robert C. Taber; William H. Russell, both of Rochester, NY.

[73] Assignee: Eastman Kodak Company, Rochester,

[22] Filed: Feb. 1, 1968 [21] Appl. No.: 702,381

Related US. Application Data [63] Continuation-in-part of Ser. No. 649,697, June 28,

1967, abandoned.

[52] U.S.Cl ..96/66.5, 96/125 [51] Int. Cl. ..G03c 1/08,G03c 5/30 [58] Field of Search ..96/66, 66.3, 95, 125

[56] References Cited UNITED STATES PATENTS 3,179,517 4/1965 Tregillus et al. ..96/29 3,295,976 1/1967 Abbott et a1 ..96/55 3,458,317 7/ 1969 Ditzer et al. ..96/94 3,459,790 8/1969 Smith et al ..260/483 OTHER PUBLICATIONS L. Larmore, Introduction to Photographic Principles, Prentice Hall, lnc., Englewood Cliffs, N.J., 1950, pps. 112, 117, 118, 119.

Primary Examiner-Norman G. Torchin Assistant Examiner-Alfonso T. Suro Pico Attorney-William H. .l. Kline, Bernard D. Wiese and Gerald E. Battist [57] ABSTRACT A photographic element comprising an acrylic interpolymer can be rapidly processed at high temperatures to provide an image record exhibiting reduced haze and improved photographic properties, The acrylic interpolymer contained in the photographic element is compatible with gelatin and has a Tg of less than 20 C. In another aspect of this invention, a photographic element comprising an acrylic interpolymer and a development modifier exhibit improved photographic properties.

25 Claims, 1 Drawing Figure U U Q G U O Q Q a DE VE L 0P F/X PATENTEDMAR 7 I972 er on bar/1 sides) F W EXPOSED SHEET FILM (emulsion lay WASH DEVELOP A TTOR/VEY NOVEL PHOTOGRAPHIC ELEMENTS AND MEANS FOR RAPID PROCESSING OF PHOTOGRAPHIC ELEMENTS This application is a continuation-in-part of U.S. Ser. No. 649,697 filed June 28, 1967, now abandoned.

This invention relates to photographic compositions, elements and processes. In one aspect, this invention relates to a means for minimizing haze in photographic elements subjected to rapid processing techniques. In another aspect, this invention relates to a method for rapidly processing a photographic element comprising a gelatino, silver halide emulsion layer which contains an acrylic interpolymer which is compatible with gelatin and has a glass transition temperature of less than about C. In still another aspect, this invention relates to a photographic silver halide emulsion containing an acrylic interpolymer and a development modifier.

Rapid processing techniques have recently been disclosed in the prior art for quickly developing photographic elements. However, the high temperatures and physical conditions generally encountered in rapid processing apparatus have resulted in a deterioration of photographic properties of the processed element. This deterioration of photographic properties is very apparent where emulsion layers having low gelatin content are used to allow faster processing times and is particularly evident in the processing of films having low gelatin content silver halide emulsions coated on both sides of a support. The high fog and haze resulting from the rapid processing (i.e., developing, fixing, washing, and drying) are especially objectionable.

In the prior art, attempts have been made to improve the photographic properties of high speed emulsions by use of synthetic polymeric materials, such as poly-N-vinyllactams, in the emulsion. However, emulsions containing poly-N-vinyllactams have often resulted in an objectionable increase in fog and haze. Gelatin over-layers have been proposed, as in Meerkamper, U.S. Pat. No. 3,058,826 issued Oct. 16, 1962, as one solution to reduce haze problems. However, photographic elements having gelatin layers, either as the silver halide emulsion vehicles or as overlayers as disclosed in Meerkamper, exhibit relatively high haze when subjected to a high temperature, unidirectional, rapid processing operation.

Therefore, it is an object of this invention to provide an improved method for rapidly processing photographic elements.

It is another object of this invention to provide novel photographic elements which can be subjected to rapid development process.

It is another object of this invention to provide a means for producing an image record in a photographic element with a resultant low haze level.

It is another object of this invention to provide a novel emulsion which can be processed in a rapid development process to give low-background fog.

It is another object of this invention to provide a novel process for rapidly developing a photographic element without substantial deterioration of the photographic properties of an element as compared to a conventional element processed in a similar manner.

These and other objects are accomplished in accordance with this invention wherein it has been found that many properties, including resistance to abrasion, haze, fog levels, con trast, D and the like of photographic elements processed by rapid processing techniques can be improved provided the processing conditions and compositions of the photographic elements are combined as disclosed herein. In one aspect of this invention a photographic element having an emulsion layer containing an acrylic interpolymer which is compatible with gelatin and has a Tg (glass transition temperature) of less than 20 C. can be processed at high temperatures to achieve rapid reaction with the processing solutions, rapid drying and a resulting low required processing time. The photographic properties of the elements processed according to this invention have improved image records whereas prior art elements had to be processed at low temperatures for comparatively long periods of time to achieve optimum image record quality.

In a typical embodiment a photographic element containing an interpolymer such as a copoly (butyl acrylate-sodium acryloyloxy propane sulfonate) can be processed in less than two minutes at temperatures of above F. and preferably at a temperature in the range of about l00l20 F. to produce an element with a lower haze or opalescence than a comparative element containing gelatin as the sole binding vehicle. The use of acrylic interpolymers in this process actually decreases the haze level and provides increased resistance to abrasion as compared with an emulsion having gelatin as the sole binder vehicle. In another embodiment of this invention we have found that photographic elements containing said acrylic interpolymer in combination with a development modifier can be subjected to rapid processing to produce an element with improved photographic properties. Typical development modifiers which can be used in the system include nitrobenzodiazoles in which nitrogen is the sole hetero atom, S-mercaptotetrazoles, and anthraquinone-Z-sulfonic acids and their alkali metal salts. The emulsions containing the acrylic interpolymers in combination with the development modifiers exhibit remarkable improvements in photographic properties, e.g., they generally have lower haze, lower fog levels, increased contrast, higher D and good resistance to abrasion.

The process conditions and emulsion combinations of this invention are especially useful in rapid unidirectional processing machines. The accompanying drawing shows schematically one type of a typical unidirectional processing machine. This machine is a roller transport system representative of rapid processing machines which are especially useful for processing X-ray films. The machine is described as unidirectional because the photographic element travels in only one directional path as opposed to a process wherein an element is immersed in a processing tank in one direction and is removed by movement in the reverse direction (i.e., such as by the conventional processes of dipping a single sheet of film into a bath and pulling it out in the reverse direction). A typical apparatus for rapid processing sheet film in a unidirectional manneris disclosed in Russell et al., US, Pat. No. 3,025,799, issued Mar. 20, 1962. Typical elements processed according to the practice of this invention comprise a film support,, such as polyethylene terephthalate, having on at least one side of said support a silver halide emulsion layer.

The polymers which can be used-according to this invention are acrylic interpolymers, i.e., those interpolymers prepared from polymerizable acrylic monomers containing the characteristic acrylic group Such polymers are conveniently prepared by the interpolymerization of an acrylic monomer with at least one dissimilar monomer which can be another acrylic monomer or some other different polymerizable ethylenically unsaturated monomer. it is, of course, understood that the acrylic interpolymers employed in the practice of this invention are compatible with gelatin and have Tg of less than 20 C. (Tg can be calculated by differential thermal analysis as disclosed in Techniques and Methods of Polymer Evaluation", Vol. 1, Marcel Dekker Inc., N. Y., 1966). A similar increase in physical and photographic properties is not achieved when polymers having a Tg of above about 20 C. are employed in the emulsions.

in one embodiment, preferred interpolymers 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. Acrylic interpolymers containing units of acrylic acid or a sulfoester acrylate are especially useful in the process. Typical polymers of this type are copoly (butyl acrylate-acrylic acid), copoly (methyl acrylate-acrylic acid), copoly (ethyl acrylate-acrylic acid), copoly (butyl acrylate-sulfopropyl acrylate) and the like. In a preferred embodiment the copolymer comprises up to about 30 percent, by weight, of acrylic acid or the sulfoester acrylate; especially good results being obtained with latex alkyl acrylate copolymers having up to about 20 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. Mlxtures of the more soluble-solution-type polymers and the latex polymers can be used within the scope of this invention to achieve the desired emulsion characteristics. The acrylic interpolymer generally comprises at least percent and to about 99 percent, by weight, of the binder vehicle for the emulsion. In the preferred embodiments the binder vehicle comprises from about 25 to about 75 percent of the acrylic interpolymer and from about 75 percent to about 25 percent, by weight, gelatin of the total binder. Generally the emulsion comprises less than 100 grams of gelatin per mole of silver halide in the emulsion to permit fast drying times of the developed emulsion. Preferably the emulsion comprises less than 75 grams of gelatin per mole of silver halide.

In another preferred embodiment of this invention, the above-mentioned copolymers contain units of a third monomer. Exceptionally good results are obtained in the process of this invention when the synthetic polymers comprise units of 1) alkyl acrylates, (2) acrylic acid or sulfoester acrylates, and (3) an acrylic monomer unit having active methylene groups in side chains such as in malonic ester groups, acetoacetic ester groups, cyanoacetic ester groups, or I, 3-diketone groups such as disclosed in Smith, U.S. Pat. No. 625,593 filed Mar. 24, 1967, now U.S. Pat. No. 3,488,708, issued Jan. 6, I970. Typical polymers of this class include copoly (ethyl acrylate-acrylic acid-2-acetoacetoxy-ethyl acetoacetoxy-ethyl methacrylate), copoly (butyl acrylatesodium acrylolyloxypropane sulfonate-2-acetoacetoxyethyl methacrylate), copoly (methyl acrylate-sodium acryloyloxypropane sulfonate-2-acetoacetoxylethyl methacrylate), copoly (butyl acrylate-acrylic acid-Z-cyanoacetoxylethyl methacrylate) and the like and mixtures thereof. The copolymers of (1) alkyl acrylates and (2) acrylic acid or the sulfoester can also contain units of (3) sulfobetaines, N- methacryloyl-N'-glycylhydrazine hydrachlorides, 2-[2- methacryl-oyloxy-ethyl] isothiouronium methane sulfonate 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.

The emulsions used in this invention may contain, for example, silver bromide, silver bromoiodide, silver chlorobromide or silver chlorobromoiodide. In particular, the processes of this invention find particular use in developing silver halide emulsions in which the halide is predominantly bromide, i.e., at least 50 mole percent bromide. In a preferred embodiment of the invention, the emulsions contain silver halides in which the halide is at least 80 percent bromide. Preferred emulsions employed in the process can be generally characterized as being high-speed emulsions and in a preferred embodiment the process is used for processing (i.e., developing, fixing, washing and drying) high-speed negative films, reversal films, medical X-ray films, and the like. Generally, these emulsions can be sensitized using any of the well-known techniques in emulsion making, e.g., by digesting with naturally active gelatin or various sulfur, selenium, tellurium compounds and/or gold compounds. The emulsions can also be sensitized with salts of noble metals of Group VIII of the Periodic Table which have an atomic weight greater than 100.

The light-sensitive compositions containing the acrylic interpolymers described herein can be coated on a wide variety of supports: in practicing this invention. The emulsion compositions can be coated on one or both sides of the support which is preferably transparent and/or flexible. Typical continuous supporting sheets include, for example, cellulose nitride film, cellulose acetate film, polyvinyl acetal film,

polystyrene film, polyethylene terephthalate film and other polyester film as well as glass, paper, metal, wood, and the like. Supports such as paper can be coated with alpha-olefin polymers, particularly polymers of alpha-olefins containing two or more carbon atoms, as exemplified by polyethylene, polypropylene, ethylenebutene, copolymers and the like.

In a preferred embodiment the light-sensitive compositions are coated on both sides of the support to provide high image density with low X-ray exposures and fluorescent screens. The acrylic interpolymers can also be used in additional layers of the photographic element, such as in layers adjacent the silver halide emulsion and etc.

Hydrophilic colloid containing layers present in the elements employed in the practice of this invention can be hardened with any suitable hardener, including chrome alum, aldehyde hardeners such as formaldehyde and mucochloric acid, aziridine hardeners, hardeners which are derivatives of dioxane, oxypolysaccharides, such as oxy starch or oxy plant gums, and the like. The emulsions of this invention generally have a hardness value above about 195 F. said hardness value being the melting point temperature of the emulsion in water. In contrast, unhardened gelatin emulsions have a melting point of about to F. The silver halide layers or other layers in the element can also contain additional additives, particularly those known to be beneficial in photographic elements including, for example, plasticizers, lubricating materials such as long chain fatty acids, silicone resins, N-alkyl B amino propionates, palmityl palmitate, and the like. The silver halide layers described herein can also contain spectral-sensitizing dyes. Suitable spectral sensitizers of this type include the cyanines, merocyanines, complex (trinuclear) cyanines, complex (trinuclear) merocyanines, styryls and hemicyanines. The silver halide layers can also be developed using incorporated developers such as polyhydroxybenzenes, aminophenols, 3-pyrazolidones and thelike.

As indicated in U.S. Pat. No. 3,142,568, issued issued July 28, I964, it is sometimes advantageous to include a surface active agent or compatible mixtures of such agents in the preparation of vinyl or addition polymers and in coating photographic materials containing such polymers. Suitable wetting agents include the nonionic, ionic and amphoteric types as exemplified by the polyoxyalkylene derivatives, amphoteric amino acid dispersing agents, including sulfobetaines and the like. Such wetting agents are disclosed in U.S. Pat. No. 2,600,831 issued June 17, I952; U.S. Pat. No. 2,271,622, issued Feb. 3, i942; U.S. Pat. No. 2,271,623, issued Feb. 3, l942; U.S. Pat. No. 2,275,727, issued Mar. 10, 1942 and U.S. Pat. No. 2,787,604, issued Apr. 2, 1957; U.S. Pat. No. 2,816,920, issued Dec. 17, I957, U.S. Pat. No. 2,739,891, issued Mar. 27, 1956, and British Pat. No. 1,022,878.

The emulsion can also contain additional additives, particularly those known to be beneficial in photographic emulsions including, for example, stabilizers or antifoggants, particularly noble metal compounds as disclosed in U.S. Pat. No. 2,566,245; U.S. Pat. No. 2,566,263, and U.S. Pat. No. 2,597,856, the substituted triazaindolizines as disclosed in U.S. Pat. Nos. 2,444,605, and 2,444,607, speed increasing materials, absorbing dyes, and the like, Sensitizers which give particularly good results in the photographic compositions disclosed herein are the alkyleneoxide polymers which can be employed alone or in combination with other materials, such as quaternary ammonium salts, as disclosed in U.S. Pat. No. 2,886,437 or with mercury compounds and nitrogen-containing compounds as disclosed in U.S. Pat. No. 2,75 L299.

As already indicated certain classes of compounds can be used in the photographic elements described herein to modify development characteristics and thereby provide a photographic element with several improved photographic properties. The development modifiers which can be employed with the emulsions of this invention are nitroazoles and mercaptoazoles in which nitrogen is the .sole hetero atom and anthraquinone-2-sulfonic sulfonic acids and their alkali-metal salts. The preferred nitroazoles and mercaptoazoles have five membered heterocyclic rings containing at least one nitrogen atom; very good results are obtained with nitroazoles such as the indazoles and the mercaptoazoles such as the tetraazoles.

The preferred nitroazoles include the nitrobenzodiazoles such as the S-nitrobenzodiazoles, sometimes named as 6- nitrobenzodiazoles due to the presence of two nitrogen atoms in the heterocyclic ring as exemplified by S-nitroindazole, 5- nitrobenzimidazole and the like. The S-nitrobenzodiazoles are employed in concentrations of about 0.1 to about 50 millimoles per mole of silver halide and preferably about 1 to about millimoles. Compounds of this type are disclosed in U.S. Pat. No. 2,214,445 issued Sept. 10, 1940.

The S-mercaptotetrazole compounds which can be employed in the practice of this invention include those having the formula:

where R is an aliphatic or aromatic radical containing up to 30. carbon atoms and SX is a mercapto function. The mercapto function or group can be in the free (-811) form or in the salt (-SX) form. X is a cation, for example, hydrogen, an alkali metal such as sodium, potassium, ammonium or an organic amine residue of such amines as triethyl amine, triethanol amine, morpholine and the like. in addition, many of the mercapto heterocyclic nitrogen compounds can be in the tautomeric form, for example, in the thione form, in which case the labile hydrogen atom in the mercapto function becomes bonded to the nitrogen atom and the C-SX group becomes a thiocarbonyl groups. The term S-mercapto tetrazole, as employed herein, is intended to cover compounds in which the mercapto function is in any of these forms. R can be hydrocarbon or nonhydrocarbon and includes alkyl or aryl radicals which can contain atoms or groups other than carbon and hydrogen. Suitable atoms or groups which can be present in R together with hydrogen and carbon include, for example, alkoxy, phenoxy, halogen, cyano, nitro, amino, substituted amino, sulfo, sulfamyl, substituted sulfamyl, sulfonylphenyl, sulfonylalkyl, sulfonamidophenyl, sulfonamidoalkyl, carboxy, carboxylate, carboxyphenol, acetamidophenyl, carbamyl, carbamylphenyl, carbamylalkyl, carbonylalkyl carbonylphenyl and similar groups. Examples of 5-mercapto tetrazoles which can be employed in the practice of this invention include l-phenyI-S-mercapto tetrazole, l-ethyl-S-mercapto tetrazole, l-anaphthyl mercapto tetrazole, l-cyclohexyl-S-mercapto tetrazole, l-(3-acetamidophenyl)-5-mercapto tetrazole, l- (3,5-dicarboxyphenyl)-5-mercapto tetrazole, and the like. The mercapto azoles are employed in concentrations of generally about 0.1 to 50 millimoles per mole of silver halide and preferably about 1 to about 15 millimoles. Compounds of this type are disclosed in U.S. Pat. No. 2,403,927 issued July 16, 1946; U.S. Pat. No. 2,271,229 issued Jan. 27, 1942; and U.S. Pat. No. 3,266,897 issued Aug. 16, 1966.

The anthraquinone sulfonic acids or salts employed in the practice of this invention are derivatives of anthraquinone and contain a sulfonic acid function in the 2 position. The sulfonic acid function can be in the free (SO;,l-l) form or in the salt (-SO M) form. M is a cation, for example, hydrogen or an alkali metal such as sodium, potassium, ammonium, an organic amine residue of such amines as triethyl amine, triethanol amine, morpholine, and the like. Suitable anthraquinone sulfonic acids or salts which can be employed in the practice of this invention include, for example, anthraquinone-2-sulfonic acid, anthraquinone-2,6-disulfonic acid, anthraquinone-2,7- disulfonic acid, anthraquinone-l,2-disulfonic acid, and the like as well as salts, particularly alkali metal salts thereof. The anthraquinone derivatives are employed in concentrations of generally about 0.1 to 50 millimoles per mole of silver halide and preferably about l-15. Compounds of this type are disclosed in U.S. Pat. No. 2,504,593 issued Apr. 18, 1950.

lnert particles can be incorporated into one or more layers of the element, e.g., to control static discharge or to enhance developer pickup. The inert particles employed for this purposes are water insoluble, solid particles, and can have an average size within a broad range. Preferred inert particles have a diameter in the range of about 5 millimicrons to about 15 microns.

The inert particles employed in the practice of this invention include any of the water insoluble particulate organic or inorganic compounds which can be used to provide the photographic element with the required surface characteristics. Examples of suitable inert particles include starch, barium sulfate, calcium carbonate, cellulose esters such as cellulose acetate propionate, cellulose others such as ethyl cellulose, synthetic resins such as polymeric esters of acrylic and methacrylic acid, as exemplified by poly methyl methacrylate, polyvinyl resins such as polyvinyl acetate, polycarbonates, homoand copolymers of styrene, inorganic oxides such as zinc oxide, silica, glass, titanium dioxide, magnesium oxide and aluminum oxide, as well as hardened gelatin grains, calcium carbonate, barium carbonate and the like. Particularly useful are silica particles having a particle size less than 50 my. as described in U.S. Pat. No. 3,053,662 issued Sept. 11, 1962, and U.S. Pat. No. 2,892,797 issued June 30, 1959.

The discrete particles can be incorporated into one or more layers on an emulsion side surface of a support in a photographic element. The inert particles can also be put into both the photographic silver halide emulsion layer and an adjacent layer such as a gelatin layer coated over the emulsion layer.

The solid inert particles are incorporated into the photographic element of this invention using any method which will achieve uniform dispersion of the particles in one or more layers of the element. For example, the inert particles can be dispersed directly in a photographic silver halide coating solution or they can be dispersed in an aqueous solution or dispersion of the silver halide binding agent, which solution is mixed with a photographic silver halide emulsion prior to coating the latter to form a light sensitive layer. ln general, the solid inert particles are present in the photographic element in concentrations in the range of about 20 to about 150 preferably about 30 to about 100 mg./ft. of support.

Upon proper selection of the proper processing solutions and processing conditions, the photographic elements of this invention can be processed and dried properly in an actual processing time of less than 2 minutes and preferably as short as 30 seconds (not including the time of transport between the various processing solutions and a drying chamber). A typical total processing time obtainable in the present process is 60 to 120 seconds from the point of feeding the film into a transport apparatus to the emergency of the dried film. ln a typical process for developing X-ray film the pH of the developer should be maintained at from about 9.5 to 10.5 using, for example, caustic alkali or alkali metal carbonate. The pH is selected to insure that development produces an X-ray image of the desired density and contrast at the selected time and temperature. The temperature of the developing solutions should be maintained between about and 120 F. Under these conditions, development is carried out until the required density and contrast is obtained; a useful development time is 25 seconds in a 60second actual processing cycle including drying time, in a roller transport system such as shown in the drawing, or seconds total time when including the time of transport of the film between the tanks and drying chamber.

The fixing solution employed in the process of our invention is a conventional fixing solution containing a silver halide solvent such as alkali metal or ammonium thiosulfate. When employing the shorter actual processing times of the order of 30 seconds, a higher concentration of the silver halide solvent is used and conversely, the temperature of the fixing solution should be maintained at from about 80 to 120 F. A representative fixing time is 12 seconds in a 60-second actual processing time.

Following treatment of the film in the fixing solution, it is washed with water at about 80 to 120 F. until substantially all of the solubilized silver salt has been removed from the film. A representative washing time is 20 seconds at 120 F. in a 60-second actual processing time.

After washing the film, it is preferably squeegeed to remove excess water and dried at about 120 to 200 F. by directing a stream of air against the emulsion surface. ln a 60-second actual processing cycle, when the emulsion contains about 450 mg. of gelatin per square foot, drying can be expected to be complete in 20 seconds or less using a stream of air of approximately 50 percent relative humidity.

In the process described it should be understood that the shorter processing times are best obtained by selection of emulsions containing the minimum amount of colloid binder vehicle, the selection of the higher processing temperatures and developing at the higher Ph values as well as fixing with the more concentrated acid fixing solutions. Emulsions containing the higher levels of gelatino colloid vehicle require drying for longer periods of time at higher temperatures.

The accompanying drawing shows in schematic form a representative roller transport system in commercial use for the development of X-ray film and particularly adapted to use in our invention.

Cut sheet X-ray film having a silver halide emulsion layer coated on both sides of the support is advanced along the path shown between staggered rollers through the development, fixing and washing tanks and through the drying section. An apparatus of this type is described in more detail in US. Pat. No. 3,025,779. In this apparatus, an actual processing time of 30 to 90 seconds is adequate. Other types of roller transport apparatus can be employed in the process of out invention. For example, apparatus can be used of the type wherein the film is advanced by means of a series of rollers, through several chambers where processing solutions aresprayed onto the emulsion surface within the mentioned temperature ranges and the film dried at elevated temperatures.

This invention can be further illustrated by the following examples of preferred embodiments thereof although it will be understood that these examples are included merely for purposes of illustration and are not intended to limit the scope of the invention unless otherwise specifically indicated.

EXAMPLE 1 A coarse-grained silver bromoiodide photographic emulsion of the type used for screen X-ray materials containing 68 grams of gelatin/Ag mole is coated on both sides of a polyester, polyethylene terephthalate support at 473 mg. Ag/ft. and 298 mg. of gelatin/ft? on each side. This sample is used as a control for comparison with the following emulsion.

A similar emulsion is prepared which contains 68 grams of gelatin and 68 grams of copoly (butyl acrylate-sodium acryloyloxypropane suIfonate-Z-acetoacetoxyethyl methacrylate) (Tg Less than C.) per mole of Ag. This emulsion is coated as above at 473 mg. Ag and 596 mg. vehicle/ft. on

Feature Haze All gelatin vehicle 1- Poor Gel: polymer vehicle 4 Slight Similar improved properties are obtained when a copoly (methylacrylate-sulfopropyl acrylate); copoly (methyl acrylate-sulfopropylacrylate-2-acetoacetoxyethyl methacrylate) and copoly (methylacrylate-3-acryloyloxy-1-methyl propanel-sulfonic acid Na salt) which all have Tgs of less than 10 C. are used as the acrylic interpolymer in the emulsion.

ln contradistinction a similar emulsion containing poly (N- vinyl lactam) when processed under similar conditions has a high haze level and relatively poor wet abrasion resistance.

EXAMPLE 2 An emulsion is prepared by the procedure of Example 1 which contains 68 grams of gelatin and 68 grams of copoly (ethyl acrylate-acrylic acid-Z-acetoacetoxyethyl methacrylate) per mole of Ag. The emulsion is coated and tested as in Example l with the following results.

Feature Haze Wet Abrasion All gelatin vehicle (control I Poor Gel:polymer vehicle 3+ Slight Example 3 Mixtures of latex type interpolymers and the more soluble-.

solution-type interpolymers can be used effectively in this invention. An emulsion similar to that of Example 1 is prepared containing 55 grams of gelatin, 15 grams of a latex polymer of copoly (butyl acrylate-sodium acryloyloxypropane sulfonate- Z-acetoacetoxyethyl methacrylate) (Tg=less than 10 C.) and 40 grams of a more soluble polymer of copoly (ethyl acrylate-' acrylic acid-2-acetoacetoxyethyl methacrylate) (Tg=less than 10 C.) made from 24 weight percent acrylic acid monomer. All vehicles are added in the given portions per mole of silver in the emulsion.

The emulsion also contained 650 mg. of S-nitroindazole and 20 mg. of 1-phenyl-5-mercaptotetrazole per mole of silver.

The emulsion is coated on both sides of a polyethylene terephthalate support at 473 mg. Ag and 596 mg. of colloid vehicle per ft. on each side of the support. A control sample contains an all gelatin vehicle with no development modifiers.

The samplesare exposed, developed and tested as in Example 1 with the following results. 1

Feature Haze Wet Abrasion All gelatin vehicle l Poor Gel: polymer vehicle 3+ Slight EXAMPLE 4 A coarse-grained silver bromoiodide photographic emulsion of the type used for screen X-ray materials is prepared containing 68 g. of gelatin and 68 g. of copoly (butyl acrylatesodium acryloyloxypropane sulfonate-2-acetoacetoxyethyl methacrylate). To one portion of the emulsion is added 0.6 grams/Ag mole of 5-nitroindazole. Comparative sample of the emulsions are coated on both sides of a polyester (polyethylene terephthalate) support at 473 mg. Ag/ft. and 576 mg. of vehicle/ft. on each side.

The dried coatings are exposed for l/50 of a second to a simulated screen exposure and processed in a unidirectional roller transport processor, i.e., a Kodak X-Omat Processor, for seconds total processing time as follows:

Development 20 seconds at F. in a 1-phenyl-3- pyrazolidone-hydroquinone developer Fixing 12 seconds at 105 F. in an ammonium thiosulfateacetic acid fixer Washing 8 seconds at 105 F.

Drying 20 seconds at 105 F.

The remaining time was used in transporting the film between the tanks, i.e., the developing and drying sections.

The comparative results are as follows:

Feature I y I og D." Control 1.45 0.21 3.34 Control S-Nitroindazole 2.55 0.05 3.70

Similar improved results are obtained when the emulsions contain 0.5 g./mole of -chlorobenzotriazole, 0.1 and 0.5 g./mole of S-methyll ,2,3-benzotriazole, 0.1 g./mole of 3-mercapto-benzothiazole, 1.0 and 2.5 g./mole of 5-carbethoxy-3-(3 -carbethoxypropyl)-4-methyl-4thiazoline-2-thione, S-mercapto-l ,2,4-triazole and sodium anthraquinone sulfonate.

EXAMPLE 5 A coarse-grained silver bromoiodide photographic emulsion of the type used for screen X-ray materials is prepared containing 68 g. of gelatin and 68 g. of copoly (ethyl acrylate acrylic acid-Z-acetoacetoxyethyl methacrylate).

To one portion of the emulsion is added 50 mg./Ag mole of phenyl-S-mercapto tetrazole (PMT). The emulsion was coated, exposed, and processed as in Example 3 with the following results.

Feature 1 Fog D Control 0.89 0.33 1.65

Conlrol+ PMT 1.17 0.15 1.69

Similar results are obtained when phenyl-S-mercapto tetrazole is used in combination with the acrylic interpolymers: copoly (methyl acrylate-sulfopropyl acrylate), copoly (methyl acrylate-sulfopropyl acrylate-2-acetoacetoxyethyl methacrylate) and copoly (butyl acrylate-acrylic acid- Z-cyanoacetoxyethyl methacrylate).

Not all compounds act as development modifiers in the emulsions of this invention. While some commonly used photographic additives do improve fog characteristics slightly, they have either no effect or an adverse effect on the sensitometric characteristics of the emulsion.

A coarse grained silver bromoiodide photographic emulsion is prepared according to Example 1 containing 68 grams per mole of silver of copoly (butyl acrylate-sodium acryloyloxypropane sulfonate-2-acetoacetoxyethyl methacrylate).

The addenda listed in the following table were added to respective samples of the emulsion. Each sample is coated on both sides of a polyethylene terephthalate support at 473 mg. of Ag per ft. and 596 g. of vehicle per ft. on each side. The coatings are exposed and processed according to Example 4 with the following results.

Addenda (gJmole of Ag) 7 Fog Control 0.88 0.21 4-hydroxy-6-methyl-l ,3.3a,

7-tetrazaidene (2) 0.86 0.21 Methyl D-arabonate (10) 0.80 0.21 l.l0-bis(piperidino)-l .10

-dioxo 2.5,6,9-tetrathiadecane In a highly preferred embodiment the emulsions of this invention contain carboxy substituted l-phenyl-Smercaptotetrazoles. The carboxy substituted l-phenyl-S-mercaptotetrazoles control the background fog at a low level in the emulsions of this invention without the desensitization associated with many antifoggants.

EXAMPLE 6 A coarse-grained silver bromoiodide photographic emulsion of the type used for screen X-ray materials containing 120 grams of gelatin/Ag mole is coated on a polyester, polyethylene terephthalate, support at 484 mg. Ag/ft. and 538 mg. gelatin/ft This sample is used as a control for comparison with the following emulsion.

A similar emulsion is prepared which contains 55 grams of gelatin and 55 grams of the alkyl acrylate copolymer, copoly (ethyl acrylate-acrylic acid-Z-acetoacetoxyethyl methacrylate) per mole of silver. To respective portions of this emulsion are added 50 mg. and 100 mg. of 1-(3,5-dicarbosyphenyl)-5-mercaptotetrazole (A) per mole of silver and 25 mg. of phenyl mercaptotetrazole (B) per mole of silver. The respective samples were coated on a polyester support after the specified hold period listed in the table below at 484 mg. of Ag/ft? and 538 mg. of vehicle per ft The above coatings are given a simulated screen exposure and developed for 3 minutes in an Elon-hydroquinone developer, fixed, washed and dried with the following results.

Addenda Hold Emulsion (mg/Ag Before Rel.

Vehicle mole) Coating Speed 1 Fog Gelatin None 100 1.63 0.06

Gelatin-polymer None 100 1.67 0.05 Gelatin-polymer 4 hour 67 1.32 0.18 Gelatin-polymer A (50) 4 hour 91 1.98 0.10 Gelatin-polymer A (100) 4 hour 95 1.68 0.04 Gelatin-polymer B (25) 4 hour 16 1.77 0.04

It is apparent that the carboxy substituted l-phenyl-S-mercaptotetrazoles provide an increase in sensitivity of the emulsion while controlling the fog at low levels.

The invention has been described in considerable detail with reference to preferred embodiments thereof, but it will be understood that variations and modifications can be effected within the spirit and scope of the invention as described hereinabove and as defined in the appended claims.

We claim:

1. A high-speed silver halide photographic emulsion comprising (l) gelatin, (2) an interpolymer comprising units of an alkyl acrylate, said interpolymer comprising between about 10 percent and about 99 percent, by weight, of the binder vehicle for the said emulsion, being compatible with gelatin and having a Tg of less than about 20 C., and (3) nitroazole, mercaptoazole or anthraquinone-2-sulfonic acid development modifier, said halide being at least mole percent bromide, and said emulsion being chemically sensitized with a compound of sulfur, selenium, tellurium or gold or a salt of a Group VIII noble metal having an atomic weight greater than 100.

2. An emulsion according to claim 1 wherein said development modifier is a mercaptotetrazole.

3. An emulsion according to claim 1 wherein said development modifier is a nitroindazole.

4. An emulsion according to claim 1 wherein said development modifier is a nitroazole or mercaptoazole having a 5 membered heterocyclic ring containing a nitrogen atom.

5. An emulsion according to claim 1 wherein said development modifier is a carboxy substituted l-phenyl-S-mercaptotetrazole.

6. An emulsion according to claim 1 wherein said development modifier is l-(3,5-dicarboxyphenyl)-5-mercaptotetrazole.

7. The emulsion of claim 1 wherein the interpolymer is copoly (butyl acrylate-sodium acryloyloxypropane sulfonate- Z-acetoacetoxyethyl methacrylate 8. The emulsion of claim 1 wherein the interpolymer is copoly (methyl acrylate-sulfopropyl acrylate).

9. The emulsion of claim 1 wherein the interpolymer is copoly (methyl acrylate-sulfopropylacerylate-2-acetoacetoxyethyl methacrylate).

10. The emulsion of claim 1 wherein the interpolymer is copoly (methyl acrylate-3-acryloyloxy-l-methyl propane-1- sulfonic acid, sodium salt).

11. The emulsion of claim 1 wherein the interpolymer is copoly (ethyl acrylate-acrylic acid-2-acetoacetoxyethyl methacrylate).

12. The emulsion of claim 1 wherein the interpolymer is copoly (butyl acrylate-acrylic acid-2-cyanoacetixtethyl methacrylate).

13. The emulsion of claim 1 wherein the interpolymer is copoly (butyl acrylate-sodium acryloyloxypropane sulfonate- 2-acetoacetoxyethyl methacrylate) and the development modifier is 5-nitroindazole.

14. The emulsion of claim 1 wherein the interpolymer is a mixture of copoly (ethyl acrylate-acrylic acid-Z-acetoacetoxyethyl methacrylate) and copoly (butyl acrylate-sodium acryloyloxypropane sulfonate-2-acetoacetoxyethyl methacrylate), and the development modifier is a mixture of 5-nitroindazole and l-phenyl-5-mercaptotetrazole.

ment modifier is l-phenyl-S-mercaptotetrazole.

20. The emulsion according to claim 1 wherein the development modifier is sodium anthraquinone sulfonate.

2l. The emulsion according to claim I wherein the development modifier is S-chlorobenzotriazole.

22. The emulsion according to claim 1 wherein the development modifier is S-methyl-1,2,3-benzotriazole.

23. The emulsion according to claim 1 wherein the development modifier is 3-mercaptobenzothiazole 24. The emulsion according to claim 1 wherein the development modifier is 5-carbethoxy-3-(3-carbethoxypropyl)-4- methyl-4-thiazoline-2-thione.

25. The emulsion according to claim 1 wherein the development modifier is 3mercaptol ,2,4-triazole.

gz g UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTEON Patent No. 3 2 ,459 Dated March 7, 1972 Inventor) Robert C. Taber and Willima H. Russell It: is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Column 3, line 32, "U.S. Pat. No. should read --U.S. Serial No.---; line 35, delete "aoetoaoetoxy-ethyl"; line 75, "nitride" should read ---nitrate---. Column L line 75, delete the first "sulfonio". Column 5, line 13, "U.S. Pat. No, 2,21h,l l 5"' should read U.S. Patent 2,2lh,L1 L ,6. Column 6, lines 5 and 6, "purposes" should read ---purpose---; line 60, "emergency" should read --emergence---. Column 7, line 39, out should read --our---. Column 8, line 5h, "sample" should read -samples---., Column 9, line 70, "1(3,5'- dioarbosyphenyl)-5-mereaptotetrazole should read -----l (3,5-- dicarboxyphenyl)-5-mercaptotetrazole; Column 10, Claim 9, "sulfopropylaeerylate" should read ---sulfopropylacrylate---.

Signed and sealed this lst day of August 1972.

(SEAL) Attest:

ROBERT GDTTSCHALK Commissioner of Patents EDWARD M.FLETCHER,JR. Attesting Officer

Claims (24)

1. 2. An emulsion according to claim 1 wherein said development modifier is a mercaptotetrazole.
2. 3. An emulsion according to claim 1 wherein said development modifier is a nitroindazole.
3. 4. An emulsion according to claim 1 wherein said development modifier is a nitroazole or mercaptoazole having a 5 membered heterocyclic ring containing a nitrogen atom.
4. 5. An emulsion according to claim 1 wherein said development modifier is a carboxy substituted 1-phenyl-5-mercaptotetrazole.
5. 6. An emulsion according to claim 1 wherein said development modifier is 1-(3,5-dicarboxyphenyl)-5-mercaptotetrazole.
6. 7. The emulsion of claim 1 wherein the interpolymer is copoly (butyl acrylate-sodium acryloyloxypropane sulfonate-2-acetoacetoxyethyl methacrylate).
7. 8. The emulsion of claim 1 wherein the interpolymer is copoly (methyl acrylate-sulfopropyl acrylate).
8. 9. The emulsion of claim 1 wherein the interpolymer is copoly (methyl acrylate-sulfopropylacerylate-2-acetoacetoxy-ethyl methacrylate).
9. 10. The emulsion of claim 1 wherein the interpolymer is copoly (methyl acrylate-3-acryloyloxy-1-methyl propane-1-sulfonic acid, sodium salt).
10. 11. The emulsion of claim 1 wherein the interpolymer is copoly (ethyl acrylate-acrylic acid-2-acetoacetoxyethyl methacrylate).
11. 12. The emulsion of claim 1 wherein the interpolymer is copoly (butyl acrylate-acrylic acid-2-cyanoacetixtethyl methacrylate).
12. 13. The emulsion of claim 1 wherein the interpolymer is copoly (butyl acrylate-sodium acryloyloxypropane sulfonate-2-acetoacetoxyethyl methacrylate) and the development modifier is 5-nitroindazole.
13. 14. The emulsion of claim 1 wherein the interpolymer is a mixture of copoly (ethyl acrylate-acrylic acid-2-acetoacetoxyethyl methacrylate) and copoly (butyl acrylate-sodium acryloyloxypropane sulfonate-2-acetoacetoxyethyl methacrylate), and the development modifier is a mixture of 5-nitroindazole and 1-phenyl-5-mercaptotetrazole.
14. 15. The emulsion of claim 1 wherein the interpolymer is copoly (ethyl acrylate-acrylic acid-2-acetoacetoxyethyl methacrylate) and the development modifier is 1-phenyl-5-mercapto-tetrazole.
15. 16. The emulsion of claim 1 wherein the interpolymer is copoly (ethyl acrylate-acrylic acid-2-acetoacetoxyethyl methylacrylate) and the development modifier is 1-(3,5-dicarboxyphenyl)-5-mercaptotetrazole.
16. 17. The emulsion of claim 1 wherein the interpolymer is copoly (butyl acrylate-sodium acryloyloxypropane sulfonate-2-acetoacetoxyethyl methacrylate) and the development modifier is sodium anthraquinone sulfonate.
17. 18. The emulsion according to claim 1 wherein the development modifier is 5nitroindazole.
18. 19. The emulsion according to claim 1 wherein the development modifier is 1-phenyl-5-mercaptotetrazole.
19. 20. The emulsion according to claim 1 wherein the development modifier is sodium anthraquinone sulfonate.
20. 21. The emulsion according to claim 1 wherein the development modifier is 5-chlorobenzotriazole.
21. 22. The emulsion according to claim 1 wherein the development modifier is 5-methyl-1,2,3-benzotriazole.
22. 23. The emulsion according to claim 1 wherein the development modifier is 3-mercaptobenzothiazole.
23. 24. The emulsion according to claim 1 wherein the development modifier is 5-carbethoxy-3-(3-carbethoxypropyl)-4-methyl-4-thiazoline-2-thione.
24. 25. The emulsion according to claim 1 wherein the development modifier is 3-mercapto-1,2,4-triazole.

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