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
  • G03C8/00—Diffusion transfer processes or agents therefor; Photosensitive materials for such processes
  • G03C8/42—Structural details
  • G03C8/52—Bases or auxiliary layers; Substances therefor
• • 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
  • G03C8/00—Diffusion transfer processes or agents therefor; Photosensitive materials for such processes

Definitions

• This invention is concerned with photography and, more particularly, with photographic processes which are conducted outside of the camera in which the film is exposed. ⁇ . S. Patent No. 3,415,644 issued December 10,
• the light-reflecting material (referred to in said patent as an "opacifying agent”) is preferably titanium dioxide, and it also performs an opacifying function, i.e., it is effective to mask the developed silver halide emulsions so that the transfer image may be viewed without interference therefrom, and it also helps to protect the photoexposed silver halide emulsions from post-exposure fogging by light passing through said transparent layer if the photoexposed film unit is removed from the camera before image-formation is completed.
• an opacifying agent is preferably titanium dioxide, and it also performs an opacifying function, i.e., it is effective to mask the developed silver halide emulsions so that the transfer image may be viewed without interference therefrom, and it also helps to protect the photoexposed silver halide emulsions from post-exposure fogging by light passing through said transparent layer if the photoexposed film unit is removed from the camera before image-formation is completed.
• 3,415,644 comprises first and second sheet-like elements, the first sheet-like element comprising an opaque base carrying a silver halide emulsion, and the second sheet-like element comprising a transparent support carrying an image layer, i.e., a layer adapted to receive an imagewise distribution of an image-forming material initially present in said firs sheet-like element.
• a processing composition adapted to develop the exposed silver halide emulsion and to form the desired image in said image layer, is distributed in a thin layer between said sheet-like elements.
• the processing composition contains a light- reflecting pigment, such as titanium dioxide, and at least one light-absorbing optical filter agent, such as a pH-sensitive phthalein dye which is colored at the initial pH of said processing composition.
• the concentrations of said light-reflecting pigment and said optical filter agent(s) are such that the layer of processing composition is sufficiently opaque to light actinic to the silver halide emulsion that the film unit may be ejected from the camera immediately after the processing composition is distributed, notwithstanding the fact that the second sheet-like element will transmit light incident on the surface thereof.
• This opacification system is quite effective and is employed in Polaroid Land SX-70 film. The light-absorbing capacity of the optical filter agent is discharged after this ability is no longer needed, so that the optical filter agent need not
• optical filter agent is a pH-sensitive dye, such as a phthalein indicator dye
• it may be discharged or decolorized by reducing the pH after a predetermined time, e.g., by making available an acid-reacting material such as a polymeric acid.
• the concentrations of the light-reflecting pigment and light-absorbing optical filter agent in the layer of processing composition will be such that that layer will have a transmission density of at least about 6 but a reflection density not greater than about 1.
• a long chain substituent e.g., a long chain alkoxy group
• a reflection density of about 1 will be recognized as very small compared with a transmission density of 6 or more for the same layer.
• concentration of optical filter agents and titanium dioxide such that the reflection density of the processing composition layer, as measured about 30 seconds after distribution, is much lower than 1, e.g., about 0.5 to 0.6. While transferring dye and the emerging dye image may be seen at opacification system reflection densities of about 0.5, the presence of such temporary coloration of the highlight or white areas of the image, and the temporary distortion of the colors of the already transferring image dyes, is aesthetically undesirable.
• the optical filter agent is a pH-sensitive dye
• it is "discharged", i.e., rendered substantially colorless, by a reduction of the pH of the strata containing the optical filter agent.
• These strata include the light-reflecting pigment layer, provided by the processing composition, as well as the image-receiving layer and any other layers between the light-reflecting pigment layer and the transparent support through which the final
• the opacification system may be considered to be "visually clear", i.e., the background provided by the titanium dioxide layer to be substantially white to the eye, when the reflection density, particularly the red reflection density, was reduced to about 0.3.
• the initial reflection density was between 0.5 and 0.6 and this reduction to about 0.3 reflection density to give "visual clearing" occurred between 5 and 6 minutes after distribution of the processing composition.
• pH reduction in the just described example was effected by a neutral polymer adapted to interact with the alkaline composition, e.g., by hydrolysis, to reduce the pH.
• the image-receiving layer comprised poly-4-vinylpyridine (mordant) in cellulose acetate (hydrolyzable neutral polymer).
• this system contemplates discharging substantially all of the opacifying dye.
• Yet another object of this invention is to provide image-receiving elements useful in such products and processes and having an optical filter agent decolorizing layer over the image-receiving layer.
• the invention accordingly comprises the several steps and the relation and order of one or more of such steps with respect to each of the others, and the product possessing the features, properties and relation of elements
• FIGURE is a diagrammatic enlarged cross-sectional view of a film unit embodying the invention, illustrating the arrangement of layers during the three illustrated stages of a monochrome diffusion transfer process, i.e., exposure, processing and finished print.
• the reflection density is the result of light -being absorbed twice by a given quantity of dye — once when the light enters and a second time when it is reflected back — it will be seen that decolorization of even a few molecules of dye adjacent the interface provides an effect which is so amplified by the optics of reflection that one can substantially lower the reflection density and increase the apparent whiteness of the layer of the processing composition providing the background against which the image is viewed without reducing the transmision density of the "white” layer to any significant extent.
• a "decolorizing" layer is provided between the image-receiving layer and the layer of processing composition.
• This decolorizing layer comprises a substantially nondiffusible agent .adapted to decolorize the small concentration of optical filter agent which is present immediately adjacent the interface between the processing composition and the decolorizing layer. It is an important feature of this invention that this decolorizing is essentially limited to the optical filter agent which is present immediately adjacent the interface between the decolorizing layer and the processing composition.
• the decolorizing layer inhibits diffusion of optical filter agent into the image-receiving layer where it may react with the mordant to form a "new species" whose color is discharged only at a lower pH; e.g. , the new species exhibits a much lower pKa and remains colored until the pH is reduced to a much lower level than otherwise would be required for decolorization.
• the remaining optical filter agent may be, and preferably is, discharged or decolorized by a subsequent pH reduction.
• this invention is primarily directed to photographic processes wherein the desired image is obtained by processing an exposed photosensitive silver halide material, with a processing composition distributed between two sheet-like elements, one of said elements including said photosensitive material.
• the processing composition is so applied and confined within and between the two sheet-like elements as not to contact or wet outer surfaces of the superposed elements, thus providing a film unit or film packet whose external surfaces are dry.
• the processing composition is viscous and preferably is distributed from a single-use rupturable container; such pressure rupturable processing containers are frequently referred to as "pods".
• the final image may be black-and-white, monochrome or multicolor and either negative or positive with respect to the photographed subject.
• the present invention is especially, if not uniquely, adapted for facilitating processing outside of a camera film units which are maintained as an integral laminate after processing, the desired image being viewed through one face of said laminate.
• the diffusible image-providing substance may be a complete dye or a dye intermediate, e.g., a color couper.
• the preferred embodiments of this invention use a dye developer, that is, a compound which is both a silver halide developing agent and a dye disclosed in ⁇ . S. Patent No. 2,983,606, issued May 9, 1961 to Howard G. Rogers.
• the dye developer is immobilized or precipitated in developed areas as a consequence of the development of the latent image.
• the dye developer In unexposed and partially exposed areas of the emulsion, the dye developer is unreacted and diffusible and thus provides an imagewise distribution of unoxidized dye developer, diffusible in the processing composition, as a function of the point-to-pointdegree of exposure of the silver halide emulsion. At least part of this imagewise distribution of unoxidized dye developer is transferred, by imbibition, to a superposed image-receiving layer to provide a reversed or positive color image of the developed image.
• the image-receiving layer preferably contains a mordant for transferred unoxidized dye developer.
• the image-receiving layer need not be separated from its superposed contact with the photosensitive element, subsequent to transfer image formation, if the support for the image-receiving layer, as well as any other layers intermediate said support and image-receiving layer, is transparent and a processing composition containing a
• OM substance e.g., a white pigment, effective to mask the developed silver halide emulsion or emulsions is applied between the image-receiving layer and said silver halide emulsion or emulsions.
• Dye developers are compounds which contain, in the same molecule, both the chromophoric system of a dye and also a silver halide developing function.
• a silver halide developing function is meant a grouping adapted to develop exposed silver halide.
• a preferred silver halide development function is a hydroquinonyl group.
• Multicolor images may be obtained using the color image-forming components, for example, dye developers, in an integral multi-layer photosensitive element, such as is disclosed in the aforementioned U. S. patents and in U. S. Patent No. 3,345,163 issued October 3, 1967 to Edwin H. Land and Howard G. Rogers.
• a suitable arrangement of this type comprises a support carrying a red-sensitive silver halide emulsion stratum, a green-sensitive silver halide emulsion stratum and a blue-sensitive silver halide emulsion stratum, said emulsions having associated therewith, respectively, for example, a cyan dye developer, a magenta dye developer and a yellow dye developer.
• the dye developer may be -utilized in the silver halide emulsion stratum, for example in the form of particles, or it may be disposed in a stratum (e.g., of gelatin) behind the appropriate silver halide emulsion stratum.
• a stratum e.g., of gelatin
• Each set of silver halide emulsion and associated dye developer strata preferably are separated from other sets by suitable interlayers.
• a separate yellow filter may be omitted.
• Stages A, B and C show diagrammatic cross-section, respectively, imaging, processing, and the finished print in one embodiment of this invention.
• the Figure illustrates the formation of a monochrome image using a single dye developer.
• a photosensitive element 30 in superposed relationship with an image-receiving element 32, with a rupturable container 16 (holding an opaque processing composition 17) so positioned as to discharge its contents between said elements upon suitable application of pressure, as by passing through a pair of pressure applying rolls or other pressure applying means (not shown).
• Photosensitive element 30 comprises an opaque support 10 carrying a layer 12 of a dye developer over which has been coated a silver halide emulsion layer 14.
• the image-receiving element 32 comprises a transparent support 24 carrying, in turn, a polymeric acid layer 22, a spacer layer 20, an image-receiving layer 18 and a decolorized layer 26.
• Photoexposure of the silver halide emulsion layer is effected through the transparent support 24 and the layers carried thereon, i.e., the polymeric acid layer 22, the spacer layer 20, the image-receiving layer 18 and the decolorizing layer 26, which layers are also transparent, the film unit being so positioned within the camera that light admitted through the camera exposure or lens system is incident upon the outer or exposure surface 24a of the transparent support 24.
• the film unit is advanced between suitable pressure-applying members, rupturing the container 16, thereby releasing and distributing a layer 17a of the opaque processing composition and thereby forming a laminate, as illustrated
• the opaque processing composition contains a film-forming polymer, a white pigment and has an initial pH at which one or more optical filter agents contained therein are colored; the optical filter agent (agents) is (are) selected to exhibit the appropriate light absorption, i.e., optical density, over the wavelength range of light actinic to the particulr silver halide emulsion(s).
• Permeation of the alkaline processing composition through the image-receiving layer 18 and the spacer layer 20 to the polymeric acid layer 22 is so controlled that the process pH is maintained at a high enough level to effect the requisite development and image transfer and to retain the optical filter agent (agents) in colored form within the processing composition layer 17a and on the silver halide emulsion side of said layer 17a, after which pH reduction effected as a result of alkali permeation into the polymeric acid layer 22 is effective to reduce the pH to a level which changes the optical filter agent to a colorless form.
• Absorption of the water from the applied layer 17a of the processing composition results in a solidified film composed of the film-forming polymer and the white pigment dispersed
• the positive transfer image in dye developer present in the image-receiving layer 18a is viewed through the transparent support 24 and the intermediate transparent layers against the reflecting layer 17b which provides an essentially white background for the dye image and also effectively masks from view the developed silver halide emulsion 14b and dye developer immobilized therein or remaining in the dye developer layer 12.
• the optical filter agent is retained within the final film unit laminate and is preferably colorless in its final form, i.e., exhibiting no visible absorption to degrade the transfer image or the white background therefor provided by the reflecting layer 17b.
• the optical filter agent may be retained in the reflecting layer under these conditions, and it may contain a suitable "anchor” or "ballast” group to control its diffusion into adjacent layers. Some of the optical filter agent may diffuse into the photosensitive component and be mordanted by the gelatin or other material present on the silver halide emulsion side of the reflecting layer 17b; optical filter mordanted in the photosensitive component 30 may be colorless or colored in its final state so long as any color exhibited by it is effectively masked by the reflecting layer 17b.
• the image-receiving element is free of gelatin; the photosensitive element contains gelatin, and the optical filter agent(s) is a pH-sensitive phthalein dye.
• photoexposure is effected through the image-receiving element. While this is a particularly useful and preferred embodiment, especially where the photosensitive element and the image-receiving element are secured together as shown in U. S. Patent Nos. 3,415,644 and 3,647,437, it will be understood that the image-receiving element may be initially positioned out of
• a light-absorbing optical filter agent preferably a pH-sensitive dye such as an indicator dye, is provided so positioned and/or constituted as not to interfere with photoexposure but so positioned between the photoexposed silver halide emulsions and the transparent support during processing after photoexposure as to absorb light which otherwise might fog the photoexposed emulsions. Furthermore, the optical filter agent is so positioned and/or constituted after processing as not to interfere with viewing the desired image shortly after said image has been formed. In the preferred embodiments, the optical filter agent is initially contained in the processing composition in colored form, together with a light-reflecting material, e.g., titanium dioxide.
• a light-reflecting material e.g., titanium dioxide.
• the concentration of indicator dye is selected to provide the optical transmission density required, in combination with other layers intermediate the silver halide emulsion laye (s) and the incident radiation, to prevent nonimagewise exposure, i.e., fogging, by incident actinic light during the performance of the particular photographic process.
• the transmission density and the indicator dye concentration necessary to provide the requisite protection from incident light may be readily determined for any photographic process by routine experimentation, as a function of film speed or sensitivity, processing time, anticipated incident light intensity, etc., as described in said U. S. Patent No. 3,647,437. It will be recognized that a particular transmission density may not be required for all portions of the spectrum, lesser density being sufficient in wavelength regions corresponding to lesser sensitivities of the particular photosensitive material.
• the light- absorbing dye is highly colored at the pH of the processing composition, e.g. , 13-14, but is substantially non-absorbing of visible light at a lower pH, e.g., less than 10-12.
• Particularly suitable are phthalein dyes having a pKa of about 13 to 13.5; many such dyes are described in the aforementioned U. S. Patent No. 3,647,437.
• This pH reduction may be effected by an acid-reacting reagent appropriately positioned in the film unit, e.g. , in a layer between the transparent support and the image-receiving layer, as described in more detail below.
• a mixture of light-absorbing materials may be used so as to obtain absorption in all critical areas of the visible and near-visible by which the silver halide emulsions, e.g., a panchromatic black-and-white silver halide emulsion or a multicolor silver halide photosensitive element, being used are exposable.
• Many dyes which change from colored to colorless as a function of pH reduction, e.g., phthalein dyes are known and appropriate selection may be made by one skilled in the art to meet the particular conditions of a given process and film unit; such dyes are frequently referred to in the chemical and related arts as indicator dyes.
• the decolorizing agent contained in the decolorizing layer may effect decolorization by any method suitable for the particular optical filter agent(s).
• One such method is the use of a very thin layer 26 of a polymeric acid, such as polyacrylic acid. If such a nondiffusible acid is used, its concentration should be kept quite low so that it does not reduce the pH within the processing composition layer 17a and cause premature decolorization or discharge of the optical filter agent therein, or significantly reduce the density of the transfer image.
• the decolorizing agent is a neutral polymeric material, such as a polyvinyl pyrrolidone or a polyether polymer, and may be used by itself or in admixture with another polymer.
• the decolorizing agent should be substantially non-diffusing from the decolorizing layer into the
• the molecular weight should be appropriately selected as discussed later. 5
• the ability of a given agent to decolorize the particular optical filter agent(s) may be readily determined by a procedure such as the following: the optical filter agent in question is dissolved in 1.5 molar aqueous potassium hydroxide to provide a solution of about 0.01
• test decolorizing agent 10 weight percent of the optical filter agent in a test tube.
• the test decolorizing agent is added to the test tube in small increments.
• Decolorizing agents which decolorize or substantially reduce the visible absorption of the optical filter agent when added to the potassium hydroxide in
• optical filter agent concentration in said solution 15 quantities less than about 35 times (by weight) the optical filter agent concentration in said solution are preferred as they avoid the need to use undesirably high decolorizing layer coverages, e.g., such thickness as might undesirably slow down or reduce the transfer of image dye.
• decolorization of a pH-sensitive optical filter agent in alkaline solution is the result of the formation of a complex of the decolorizing agent with the pH-sensitive dye, such complex exhibiting a higher apparent pKa than said pH-sensitive dye in said alkaline solution.
• This complexation is believed to involve the cation of the alkali, e.g., K + .
• the cation binding increases the bulk or polarizability the apparent pK moves higher, thus "decolorizing" without reducing the pH.
• the polyethers found useful have the property of binding cations, and when many cations are bound the polyether or other polymer decolorizing agent becomes a "super cation" and changes the apparent pK of the phthalein dye.
• Var ⁇ ing the ratios a, b and c will vary the hydrophobic- hydrophillic balance of the block copolymer and such -varying may be of value in the practice of this invention.
• Other polyoxyalkylene polymers such as high molecular weight polyethylene glycol (m.wt. 6000) commercially available under the tradename Carbowax 6000 also may be used, although the above block copolymers are more effective and are preferred.
• poly-N-vinylpyrrolidone e.g., that available under the tradename Type NP K-90 from GAF Corp.
• the optical filter agent is a pH-sensitive dye, such as a phthalein dye
• a controlled decolorization by pH reduction may be effected by using a very thin coating of a polymeric acid as the decolorizing layer.
• a polymeric acid decolorizing layer mention may be made of a layer of about 15-25 mg/ft 2 of a polyacrylic acid which has been adjusted to a pH of about 4 with potassium hydroxide.
• Example 1 A multicolor photosensitive element using, as the cyan, magenta and yellow dye developers
• a blue-sensitive gelatino silver iodobromide emulsion layer including 4'-methylphenyl hydroquinone coated at a coverage of about 119 mg/ft 2 of silver, about 62 mg/ft 2 of gelatin and about 19 mg/ft 2 of 4'-methylphenyl hydroquinone;
• OMPI WIp o 9. a layer of gelatin coated at a coverage of about 45 mg/ft 2 of gelatin and containing about 4 mg/ft 2 of carbon black.
• a transparent 4 mil polyethylene terephthalate film base was coated, in succession, . with the following layers to form an image-receiving component:
• a polymeric acid layer a mixture of a partial butyl ester of polyethylene/maleic anhydride copolymer and polyvinyl butyral at a ratio of about 9:1 at a coverage of about 2,500 mg/ft 2 ;
• timing layer containing about a 45:0.7 ratio of a 60-30-4-6 copolymer of butylacrylate, diacetone acrylamide, styrene and methacrylic acid and polyvinyl alcohol at a coverage of about 450 mg/ft 2 ; and 3. an image-receiving layer containing a 2:1:1 mixture of polyvinyl alcohol, poly-4-vinyl pyridine and a graft copolymer of 4'-vinyl pyridine and vinylbenzyl trimethyl ammonium chloride on hydroxyethyl cellulose (2.2:1:2.2 ratio) at a coverage of about 300 mg/ft 2 .
• the image-receiving layer there was coated about 100 mg/ft2 of a 70:30 mixture of Pluronic F-127 polyoxyethylene polyoxyprop lene block copolymer and polyvinyl alcohol as a decolorizing layer.
• the photosensitive component was photoexposed and then taped to one end of the image-receiving component with a rupturable container retaining an aqueous alkaline processing solution fixedly mounted on the leading edge of each of the components, by pressure-sensitive tapes to make a film unit, so that, upon application of compressive pressure to the container to rupture the container's marginal seal, its contents would be distributed between the decolorizing layer and the gelatin overcoat layer of the photosensitive component.
• the photoexposure was such that a portion was given a "white” exposure, i.e., all three silver halide layers were fully exposed so that the corresponding area of the positive transfer image would be "white”.
• the aqueous alkaline processing compositio comprised: Water 00 CC
• 6-methyl uracil 0. 6 g - bis-( ⁇ -aminoethyl)-sulfide 0 . 04 g.
• Colloidal silica (solids based on 30% Si ⁇ 2 dispersion) 0.56 g.
• a layer approximately 0.0030" thick of the processing composition was distributed by passing the film unit between a pair of pressure-applying rolls and into a lighted area. 5 The resulting laminate was maintained intact to provide a multicolor integral negative-positive reflection print which exhibited good color quality and separation.
• a control differing only in the absence of the decolorizing layer was processed in the same manner.
• the 0 red, green and blue reflection densities of the "white" area of the transfer image were measured at intervals indicated before, beginning 10 seconds after the processing composition was applied.
• the use of the decolorizing layer in 10 seconds reduced the reflection densities attributable to the optical filter agent to densities which required 120 seconds to obtain in the absence of this layer.
• Example 2 The procedure described in Example 1 was repeated with a photosensitive element using the same yellow and cyan dye developers and a magenta dye developer of the formula
• Example 3 An image-receiving element found to be effective in practicing this invention was prepared as described in Example 1 except that the timing layer comprised a mixture . of about 7 parts of hydroxypropyl cellulose (Klucel J12HB sold by Hercules, Inc. ) and about 4 parts of polyvinyl alcohol, coated to form a layer about 0.27 mils thick.
• the timing layer comprised a mixture . of about 7 parts of hydroxypropyl cellulose (Klucel J12HB sold by Hercules, Inc. ) and about 4 parts of polyvinyl alcohol, coated to form a layer about 0.27 mils thick.
• Example 4 5 An image-receiving element found to be effective in practicing this invention was prepared by coating a transparent 4 mil polyethylene terephthalate film base with the following layers:
• a polymeric acid layer a mixture of a 10 partial butyl ester of polyethylene/maleic anhydride copolymer and polyvinyl butyral at a ratio of about 9:1 at a coverage of about 2450 mg/ft 2 ;
• timing layer containing about a 45:0.7 ratio of a 60-30-4-6 copolymer of butylacrylate, diacetone
• an image-receiving layer comprising 300 mg/ft 2 of a graft copolymer of 4-vinylpyridine and vinylbenzyl trimethyl ammonium chloride on hydroxyethyl cellulose in a
• a decolorizing layer comprising 70 mg/ft 2 of Pluronic F-127 polyoxyethylene polypropylene block copolymer and 30 mg/ft 2 of polyvinyl alcohol.
• Such a mixed polymer decolorizing layer may be particularly " useful in embodiments where the positive and negative components are temporarily laminated, as discussed above, prior to distribution of the processing composition, so that the components may be delaminated by the processing composition without harm to the decolorizing layer.
• the concentration of the decolorizing agent effective for any particular photographic system may be readily determined by routine experimentation.
• the decolorizing layer comprised a 70:30 mixture by weight of Pluronic F-127 polyoxyethylene polyoxypropylene block copolymer and polyvinyl alcohol coated at about 100 mg/ft 2 .
• the wide concentrations which may be used it may be noted that good results also have been obtained with the same polymer mixture coated at about 25 mg/ft 2 .
• the decolorizing layer comprises a polyoxyalkylene polymer hydrogen-bonded to another polymer to provide a "hard" decolorizing layer so as to resist rub off and blocking.
• a particularly effective polymer for hydrogen bonding a polyether decolorizing agent is a copolymer of diacetone acrylamide and methacrylic acid, preferably a 1:1 monomer ratio. Hydrogen bonding — a non-valent bonding — is believed to occur between the -COOH groups provided by the methacrylic acid and the oxygen of the ether group (-CH2-CH 2 -0-CH 2 -CH2-) .
• the diacetone acrylamide provides a hydrophobic property, and the ratio of the two monomers may be adjusted to provide the balance of hydrophillic and hydrophobic properties desired for a given photographic system.
• 1:1 copolymers of methacrylic acid and diacetone acrylamide having a molecular weight of about 10,000 to 20,000 have been found to be particularly useful.
• the polymeric polyether preferably has a molecular weight of at least about 2,000; the molecular weight in combination with the hydrophillic/hydrophobic properties of the polymeric polyether should be such as to render it substantially nondiffusible from the decolorizing layer.
• ether groups do not hydrogen bond with sufficient -COOH groups to give the desired "hardness", e.g., because the molecular geometry does not provide the appropriate "fit”
• another hydrogen bonding polymer e.g., polyvinyl pyrrolidone
• Hydrogen bonding also may occur between the carboxyl group and the amide groups.
• the particular hydrogen bonding group is not important, and suitable materials may be readily selected by routine experimentation.
• the hydrogen bonded complex should precipitate in water. The hydrogen bond is reversible in aqueous alkaline solution, thus making the polyether decolorizing agent available to complex with the phthalein optical filter agent and to permit rapid diffusion of the image dye(s) through the decolorizing layer to the image- receiving layer.
• methacrylic acid is a preferred monomer in the hydrogen bonding polymer.
• Acrylic acid also may be used but is a less effective hydrogen bonding agent, possibly because fewer carboxyl groups are properly positioned to hydrogen bond with the polyether.
• the pendant methyl groups of the methacrylic acid moieties are believed to limit the ability of the carboxyl group to rotate around the polymer backbone, so that more of the carboxyl groups are properly positioned.
• Suitable coating solvents include aqueous ethanol, to which may be added a ketone such as methyl ethyl ketone.
• the solvent system should be selected to avoid having an adverse effect upon the image-receiving layer and to minimize the formation of haze.
• suitable solvent systems for coating such decolorizing layers include (by volume) (1) an 80/20 water/ethanol mixture and (2) 50/35/15 acetone, ethanol. and water.
• the DAA/MAA copolymer is added as the ammonium salt, with the free acid being regenerated during drying by volatilization of ammonia.
• Example 5 An image-receiving element was prepared by coating a transparent subcoated polyethylene terephthalate 4 mil (0.1 mm) support with the following layers:
• a neutralizing layer comprising approximately 9 parts of a half-butyl ester of polyethylene/maleic anhydride and 1 part of polyvinyl butyral coated at a coverage of about 2500 mg./ft 2 (about 26,900 mg/m 2 );
• timing layer comprising about 270 mg./ft 2 (about 2900 mg/m 2 ) of a 60.6/29/6.3/3.7/0.4 pentapolymer of butylacrylate, diacetone acrylamide, styrene, methacrylic acid and acrylic acid and about 30 mg./ft 2 (about 320 mg./ft 2 of polyvinyl alcohol;
• An image-receiving element was prepared as described in Example 5 except that the copolymer of diacetone acrylamide and methacrylic acid was 1:1.
• Example 7 An image-receiving element was prepared as described in Example 6 except that the ratio of the diacetone acrylamide/methacrylic acid polymer, Igepal CO-890 and polyvinyl pyrrolidone was 1/0.75/0.35.
• Example 8 An image-receiving element was prepared as described in Example 7 except that the neutralizing and timing layers were omitted.
• Example 9 An image-receiving element was prepared, by coating a transparent subcoated polyethylene terephthalate 4 mil (0.1 mm) support with the following layers:
• an image-receiving layer comprising about 3170 mg./m 2 of a graft copolymer of 2.2 parts 4-vinyl pyridine and 1 part vinyl benzyl trimethyl ammonium chloride on 2.2 parts of hydroxyethyl cellulose and about 43 mg./m 2 of 1,4-butanediol diglycidyl ether; and
• a decolorizing layer comprising about 1076 mg/m 2 of a mixture of 1 part 1:1 copolymer of diacetone acrylamide and methacrylic acid, 0.75 part Igepal CO-890, and 0.35 part of polyvinyl pyrrolidone.
• Polyethylene glycol (mol. wt. about 4000) 0.38 g- bis-( -aminoethyl)-sulfide 0.017 g-
• Colloidal silica (30% dispersion) 0.78 g-
• the background provided by the layer of titanium dioxide appeared apparently substantially white to the viewer within about 5 to 10 seconds after the processing composition was distributed between the image-receiving element, demonstrating that the decolorizing polyether had been effective.
• the decolorizing layers were found to be very resistant to rub off and blocking.
• the positive component 32 and the negative component 30 are temporarily laminated to each other so that the decolorizing layer 26 is in optical contact with the outer layer of the negative component 30.
• This bond should be of such a nature that these layers may be readily separated by the distribution of the processing composition following rupture of the pod 17.
• a particularly useful method of providing such a temporary lamination is to apply an aqueous solution of a polyethylene glycol, e.g., a polyethylene glycol having a molecular weight of about 6000 such as that commercially available under the tradename "Carbowax 6000" from Union Carbide Corporation. Such uses of polyethylene glycols are disclosed in U. S. Patent No. 3,793,023 issued February 19, 1974 to Edwin H. Land and to which reference may be made.
• a particularly useful composition to provide such a temporary lamination is a 50:50 mixture by weight of Carbowax 6000 and Pluronic F-127.
• the positive component 32 and the negative component 30 are held in superposed relationship without being temporaril laminated together.
• the decolorizing layer also acts to prevent blocking of the positive and negative components in the integral film unit during storage prior to use.
• the processing composition should include a viscosity-increasing polymer of the type which, when the composition is spread and dried, forms a relatively firm and stable film.
• High molecular weight polymers are preferred, and include cellulosic polymers such as sodium carboxymethyl cellulose, hydroxyethyl cellulose and hydroxyethyl carboxymethyl cellulose.
• Another class of useful viscosity- increasing polymers comprises the oxime polymers dis ⁇ losed and claimed in the copending application of Lloyd D. Taylor, Serial No. 894,545 filed April 7, 1978.
• Suitable oxime polymers include polydiacetone acrylamide oxime as well as copolymers, e.g., grafts of diacetone acrylamide oxime onto hydroxyethyl-cellulose. It has been found that the decolorizing of the optical filter agent immediately adjacent the interface is particularly effective when the 5 concentration of the viscosity-providing polymer is about 1% by weight or less, e.g., about 0.8% by weight as in the above examples.
• Neutralizing layers such as the polymeric acid layer 22 are well known in the art and are described in
• composition containing the optical filter agent 15 composition containing the optical filter agent.
• Addition of the polyoxyalkylene decolorizing agents to the image-receiving layer also has been found to be useful. A higher concentration per unit area of the polyether decolorizing agent is necessary, however, when it is
• Image-receiving elements wherein the polyether decolorizing agent has been incorporated into the image-receiving layer may be prepared, for example, by replacing the
• the amount of water present is sufficient to dissolve all of the polyoxyethylene polyoxypropylene block copolymer added, even at a 100:1 ratio. It is believed that the polyoxyalkylene decolorizing agent must be in solution to decolorize the phthalein dyes, and that one of the factors aiding in limiting the decolorization in the photographic process to the optical filter agent immediately adjacent the interface is that the amount of water available from the applied processing composition is too small to dissolve very much of the polyoxyalkylene polymer in the decolorizing layer.
• the concentration of the decolorizing agent is such that in the absence of a pH neutralizing mechanism, such as the polymeric acid layer, the decolorizing agent is insufficient to discharge or "clear" all of the optical filter agent present.
• a pH neutralizing mechanism such as the polymeric acid layer
• such a polymeric acid layer may be positioned adjacent the support carrying the photosensitive strata.
• Dye developers are preferred image-providing substances, as indicated above, and constitute an example of initially diffusible image dye- providing substances.
• Other useful dye image-providing substances include initially diffusible dyes useful as image dyes per se and which couple with the oxidation product of a silver halide developing agent to provide a non-diffusible product, initially diffusible color couplers which couple with the oxidation product of a silverhalide developing agent to provide image dyes, initially non-diffusible compounds which react with the oxidation product of a silver halide developing agent, as by coupling or by cross-oxidation, to release a diffusible dye useful as an image dye per se.
• the final image may be formed as a result of the diffusion transfer of a soluble complex of undeveloped silver halide, in which event the image may be in silver as is well known.
• a soluble silver complex formed from undeveloped silver halide may be used to effect a cleavage reaction and release a dye or dye intermediate for transfer. Since these image-forming processes are well known and form no part per se of the present invention, it is not necessary to describe them in detail herein.
• the transfer image may be positive or negative, with respect to the photographed subject matter, as a function of the particular image-forming system employed.
• the silver halide emulsion' may be negative-working or positive-working (e.g., internal latent image) as appropriate for the particular imaging system.

Landscapes

• Physics & Mathematics (AREA)
• General Physics & Mathematics (AREA)
• Engineering & Computer Science (AREA)
• Architecture (AREA)
• Structural Engineering (AREA)
• Silver Salt Photography Or Processing Solution Therefor (AREA)

Priority Applications (1)

Applications Claiming Priority (2)

Publications (1)

Family

ID=21868023

Family Applications (1)

Country Status (4)

Cited By (2)

Citations (6)

Family Cites Families (1)

• 1980
  • 1980-04-24 WO PCT/US1980/000460 patent/WO1980002333A1/en active IP Right Grant
  • 1980-04-24 DE DE8080900938T patent/DE3069337D1/de not_active Expired
  • 1980-04-24 JP JP55501108A patent/JPS6245540B2/ja not_active Expired
  • 1980-11-04 EP EP19800900938 patent/EP0027461B1/en not_active Expired

Patent Citations (6)

Non-Patent Citations (1)

Also Published As

Similar Documents

Legal Events