EP0828184A1 - Imaging element containing an electrically conductive polymer blend - Google Patents
Imaging element containing an electrically conductive polymer blend Download PDFInfo
- Publication number
- EP0828184A1 EP0828184A1 EP97202603A EP97202603A EP0828184A1 EP 0828184 A1 EP0828184 A1 EP 0828184A1 EP 97202603 A EP97202603 A EP 97202603A EP 97202603 A EP97202603 A EP 97202603A EP 0828184 A1 EP0828184 A1 EP 0828184A1
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- Prior art keywords
- film
- layer
- imaging element
- conductive
- sulfonic acid
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Classifications
-
- G—PHYSICS
- G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
- G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
- G03G5/00—Recording members for original recording by exposure, e.g. to light, to heat, to electrons; Manufacture thereof; Selection of materials therefor
- G03G5/10—Bases for charge-receiving or other layers
- G03G5/105—Bases for charge-receiving or other layers comprising electroconductive macromolecular compounds
- G03G5/108—Bases for charge-receiving or other layers comprising electroconductive macromolecular compounds the electroconductive macromolecular compounds being anionic
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
- B41M—PRINTING, DUPLICATING, MARKING, OR COPYING PROCESSES; COLOUR PRINTING
- B41M5/00—Duplicating or marking methods; Sheet materials for use therein
- B41M5/26—Thermography ; Marking by high energetic means, e.g. laser otherwise than by burning, and characterised by the material used
- B41M5/40—Thermography ; Marking by high energetic means, e.g. laser otherwise than by burning, and characterised by the material used characterised by the base backcoat, intermediate, or covering layers, e.g. for thermal transfer dye-donor or dye-receiver sheets; Heat, radiation filtering or absorbing means or layers; combined with other image registration layers or compositions; Special originals for reproduction by thermography
- B41M5/42—Intermediate, backcoat, or covering layers
- B41M5/44—Intermediate, backcoat, or covering layers characterised by the macromolecular compounds
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
- B41M—PRINTING, DUPLICATING, MARKING, OR COPYING PROCESSES; COLOUR PRINTING
- B41M5/00—Duplicating or marking methods; Sheet materials for use therein
- B41M5/50—Recording sheets characterised by the coating used to improve ink, dye or pigment receptivity, e.g. for ink-jet or thermal dye transfer recording
- B41M5/52—Macromolecular coatings
- B41M5/5254—Macromolecular coatings characterised by the use of polymers obtained by reactions only involving carbon-to-carbon unsaturated bonds, e.g. vinyl polymers
-
- 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
- G03C1/76—Photosensitive materials characterised by the base or auxiliary layers
- G03C1/85—Photosensitive materials characterised by the base or auxiliary layers characterised by antistatic additives or coatings
- G03C1/89—Macromolecular substances therefor
Definitions
- the present invention relates in general to imaging elements, such as photographic, electrostatographic, inkjet and thermal imaging elements, and in particular to imaging elements comprising a support, an image-forming layer and a transparent electrically-conductive layer. More specifically, this invention relates to the preparation of water-soluble blends of polyaniline complexes of poly(styrene sulfonic acid) or poly(styrene-co-styrene sulfonic acid) with other polymers that can form conductive films that are sufficiently transparent for photographic applications, and retain their conductivity after photographic processing with or without the use of a protective overcoat layer.
- the charge generated during the coating process results primarily from the tendency of webs of high dielectric polymeric film base to charge during winding and unwinding operations (unwinding static), during transport through the coating machines (transport static), and during post-coating operations such as slitting and spooling. Static charge can also be generated during the use of the finished photographic film product.
- unwinding static winding and unwinding operations
- transport static transport through the coating machines
- post-coating operations such as slitting and spooling.
- Static charge can also be generated during the use of the finished photographic film product.
- the winding of roll film out of and back into the film cassette especially in a low relative humidity environment, can result in static charging.
- high-speed automated film processing can result in static charge generation.
- Sheet films are especially subject to static charging during removal from light-tight packaging (e.g., x-ray films).
- Antistatic layers can be applied to one or to both sides of the film base as subbing layers either beneath or on the side opposite to the light-sensitive silver halide emulsion layers.
- An antistatic layer can alternatively be applied as an outer coated layer either over the emulsion layers or on the side of the film base opposite to the emulsion layers or both.
- the antistatic agent can be incorporated into the emulsion layers.
- the antistatic agent can be directly incorporated into the film base itself.
- a wide variety of electrically-conductive materials can be incorporated into antistatic layers to produce a wide range of conductivities.
- Most of the traditional antistatic systems for photographic applications employ ionic conductors. Charge is transferred in ionic conductors by the bulk diffusion of charged species through an electrolyte.
- Antistatic layers containing simple inorganic salts, alkali metal salts of surfactants, ionic conductive polymers, polymeric electrolytes containing alkali metal salts, and colloidal metal oxide sols (stabilized by metal salts) have been described previously.
- the conductivities of these ionic conductors are typically strongly dependent on the temperature and relative humidity in their environment. At low humidities and temperatures, the diffusional mobilities of the ions are greatly reduced and conductivity is substantially decreased.
- antistatic backcoatings often absorb water, swell, and soften. In roll film, this results in adhesion of the backcoating to the emulsion side of the film. Also, many of the inorganic salts, polymeric electrolytes, and low molecular weight surfactants used are water-soluble and are leached out of the antistatic layers during processing, resulting in a loss of antistatic function.
- colloidal metal oxide sols which exhibit ionic or electronic conductivity when included in antistatic layers are often used in imaging elements. Typically, alkali metal salts or anionic surfactants are used to stabilize these sols.
- a thin antistatic layer consisting of a gelled network of colloidal metal oxide particles (e.g., silica, antimony pentoxide, alumina, titania, stannic oxide, zirconia) with an optional polymeric binder to improve adhesion to both the support and overlying emulsion layers has been disclosed in EP 250,154.
- An optional ambifunctional silane or titanate coupling agent can be added to the gelled network to improve adhesion to overlying emulsion layers (e.g., EP 301,827; U.S.
- Patent No. 5,204,219) along with an optional alkali metal orthosilicate to minimize loss of conductivity by the gelled network when it is overcoated with gelatin-containing layers
- an optional alkali metal orthosilicate to minimize loss of conductivity by the gelled network when it is overcoated with gelatin-containing layers
- coatings containing colloidal metal oxides e.g., antimony pentoxide, alumina, tin oxide, indium oxide
- colloidal silica with an organopolysiloxane binder afford enhanced abrasion resistance as well as provide antistatic function (U.S. Patent Nos. 4,442,168 and 4,571,365).
- Antistatic systems employing electronic conductors have also been described. Because the conductivity depends predominantly on electronic mobilities rather than ionic mobilities, the observed electronic conductivity is independent of relative humidity and only slightly influenced by the ambient temperature. Antistatic layers have been described which contain conjugated polymers, conductive carbon particles or semiconductive inorganic particles.
- Trevoy U.S. Patent 3,245,833 has taught the preparation of conductive coatings containing semiconductive silver or copper iodide dispersed as particles less than 0.1 ⁇ m in size in an insulating film-forming binder, exhibiting a surface resistivity of 10 2 to 10 11 ohms per scare .
- the conductivity of these coatings is substantially independent of the relative humidity.
- the coatings are relatively clear and sufficiently transparent to permit their use as antistatic coatings for photographic film.
- Trevoy found (U.S. Patent 3,245,833)
- Patent 3,428,451 that it was necessary to overcoat the conductive layer with a dielectric, water-impermeable barrier layer to prevent migration of semiconductive salt into the silver halide emulsion layer during processing. Without the barrier layer, the semiconductive salt could interact deleteriously with the silver halide layer to form fog and a loss of emulsion sensitivity. Also, without a barrier layer, the semiconductive salts are solubilized by processing solutions, resulting in a loss of antistatic function.
- a highly effective antistatic layer incorporating an "amorphous" semiconductive metal oxide has been disclosed by Guestaux (U.S. Patent 4,203,769).
- the antistatic layer is prepared by coating an aqueous solution containing a colloidal gel of vanadium pentoxide onto a film base.
- the colloidal vanadium pentoxide gel typically consists of entangled, high aspect ratio, flat ribbons 50-100 ⁇ wide, 10 ⁇ thick, and 1,000-10,000 ⁇ long. These ribbons stack flat in the direction perpendicular to the surface when the gel is coated onto the film base.
- vanadium pentoxide gels (1 ⁇ -1 cm -1 ) which are typically three orders of magnitude greater than is observed for similar thickness films containing crystalline vanadium pentoxide particles.
- low surface resistivities can be obtained with very low vanadium pentoxide coverages. This results in low optical absorption and scattering losses.
- the thin films are highly adherent to appropriately prepared film bases.
- vanadium pentoxide is soluble at high pH and must be overcoated with a non-permeable, hydrophobic barrier layer in order to survive processing. When used with a conductive subbing layer, the barrier layer must be coated with a hydrophilic layer to promote adhesion to emulsion layers above. (See Anderson et al, U.S. Patent 5,006,451.)
- Conductive fine particles of crystalline metal oxides dispersed with a polymeric binder have been used to prepare optically transparent, humidity insensitive, antistatic layers for various imaging applications.
- Many different metal oxides -- such as ZnO, TiO 2 , ZrO 2 , SnO 2 , Al 2 O 3 , In 2 O 3 , SiO 2 , MgO, BaO, MoO 3 and V 2 O 5 -- are alleged to be useful as antistatic agents in photographic elements or as conductive agents in electrostatographic elements in such patents as U.S. 4,275,103, 4,394,441, 4,416,963, 4,418,141, 4,431,764, 4,495,276, 4,571,361, 4,999,276 and 5,122,445.
- Preferred metal oxides are antimony doped tin oxide, aluminum doped zinc oxide, and niobium doped titanium oxide. Surface resistivities are reported to range from 10 6 -10 9 ohms per square for antistatic layers containing the preferred metal oxides. In order to obtain high electrical conductivity, a relatively large amount (0.1-10 g/m 2 ) of metal oxide must be included in the antistatic layer. This results in decreased optical transparency for thick antistatic coatings.
- the high values of refractive index (>2.0) of the preferred metal oxides necessitates that the metal oxides be dispersed in the form of ultrafine ( ⁇ 0.1 ⁇ m) particles in order to minimize light scattering (haze) by the antistatic layer.
- Antistatic layers comprising electro-conductive ceramic particles, such as particles of TiN, NbB 2 , TiC, LaB 6 or MoB, dispersed in a binder such as a water-soluble polymer or solvent-soluble resin are described in Japanese Kokai No. 4/55492, published February 24, 1992.
- Fibrous conductive powders comprising antimony-doped tin oxide coated onto non-conductive potassium titanate whiskers have been used to prepare conductive layers for photographic and electrographic applications. Such materials are disclosed, for example, in U.S. Patents, 4,845,369 and 5,116,666. Layers containing these conductive whiskers dispersed in a binder reportedly provide improved conductivity at lower volumetric concentrations than other conductive fine particles as a result of their higher aspect ratio.
- the benefits obtained as a result of the reduced volume percentage requirements are offset by the fact that these materials are relatively large in size such as 10 to 20 micrometers in length, and such large size results in increased light scattering and hazy coatings.
- Electrically-conductive layers are also commonly used in imaging elements for purposes other than providing static protection.
- imaging elements comprising a support, an electrically-conductive layer that serves as an electrode, and a photoconductive layer that serves as the image-forming layer.
- Electrically-conductive agents utilized as antistatic agents in photographic silver halide imaging elements are often also useful in the electrode layer of electrostatographic imaging elements.
- an imaging element for use in an imaging-forming process comprises a support, an image-forming layer, and a tranparent electrically-conductive layer comprising polyaniline styrene sulfonic acid.
- the transparent electrically-conductive layer includes the polyaniline styrene sulfonic acid dispersed in a film-forming binder.
- the imaging elements of this invention can be of many different types depending on the particular use for which they are intended. Such elements include, for example, photographic, electrostatographic, photothermographic, migration, electrothermographic, dielectric recording and thermal-dye-transfer imaging elements.
- Photographic elements which can be provided with an antistatic layer in accordance with this invention can differ widely in structure and composition.
- they can vary greatly in regard to the type of support, the number and composition of the image-forming layers, and the kinds of auxiliary layers that are included in the elements.
- the photographic elements can be still films, motion picture films, x-ray films, graphic arts films, paper prints or microfiche. They can be black-and-white elements, color elements adapted for use in a negative-positive process, or color elements adapted for use in a reversal process.
- Photographic elements can comprise any of a wide variety of supports.
- Typical supports include cellulose nitrate film, cellulose acetate film, poly(vinyl acetal) film, polystyrene film, poly(ethylene terephthalate) film, poly(ethylene naphthalate) film, polycarbonate film, glass, metal, paper, polymer-coated paper, and the like.
- the image-forming layer or layers of the element typically comprise a radiation-sensitive agent, e.g., silver halide, dispersed in a hydrophilic water-permeable colloid.
- Suitable hydrophilic vehicles include both naturally-occurring substances such as proteins, for example, gelatin, gelatin derivatives, cellulose derivatives, polysaccharides such as dextran, gum arabic, and the like, and synthetic polymeric substances such as water-soluble polyvinyl compounds like poly(vinylpyrrolidone), acrylamide polymers, and the like.
- a particularly common example of an image-forming layer is a gelatin-silver halide emulsion layer.
- an image comprising a pattern of electrostatic potential is formed on an insulative surface by any of various methods.
- the electrostatic latent image may be formed electrophotographically (i.e., by imagewise radiation-induced discharge of a uniform potential previously formed on a surface of an electrophotographic element comprising at least a photoconductive layer and an electrically-conductive substrate), or it may be formed by dielectric recording (i.e., by direct electrical formation of a pattern of electrostatic potential on a surface of a dielectric material).
- the electrostatic latent image is then developed into a toner image by contacting the latent image with an electrographic developer (if desired, the latent image can be transferred to another surface before development).
- the resultant toner image can then be fixed in place on the surface by application of heat and/or pressure or other known methods (depending upon the nature of the surface and of the toner image) or can be transferred by known means to another surface, to which it then can be similarly fixed.
- the surface to which the toner image is intended to be ultimately transferred and fixed is the surface of a sheet of plain paper or, when it is desired to view the image by transmitted light (e.g., by projection in an overhead projector), the surface of a transparent film sheet element.
- the electrically-conductive layer can be a separate layer, a part of the support layer or the support layer.
- conducting layers There are many types of conducting layers known to the electrostatographic art, the most common being listed below:
- Conductive layers (d), (e) and (f) can be transparent and can be employed where transparent elements are required, such as in processes where the element is to be exposed from the back rather than the front or where the element is to be used as a transparency.
- Thermally processable imaging elements including films and papers, for producing images by thermal processes are well known. These elements include thermographic elements in which an image is formed by imagewise heating the element. Such elements are described in, for example, Research Disclosure , June 1978, Item No. 17029; U.S. Patent No. 3,457,075; U.S. Patent No. 3,933,508; and U.S. Patent No. 3,080,254.
- Photothermographic elements typically comprise an oxidation-reduction image-forming combination which contains an organic silver salt oxidizing agent, preferably a silver salt of a long-chain fatty acid.
- organic silver salt oxidizing agents are resistant to darkening upon illumination.
- Preferred organic silver salt oxidizing agents are silver salts of long-chain fatty acids containing 10 to 30 carbon atoms.
- useful organic silver salt oxidizing agents are silver behenate, silver stearate, silver oleate, silver laurate, silver hydroxystearate, silver caprate, silver myristate and silver palmitate. Combinations of organic silver salt oxidizing agents are also useful.
- useful silver salt oxidizing agents which are not silver salts of long-chain fatty acids include, for example, silver benzoate and silver benzotriazole.
- Photothermographic elements also comprise a photosensitive component which consists essentially of photographic silver halide.
- a photosensitive component which consists essentially of photographic silver halide.
- the latent image silver from the silver halide acts as a catalyst for the oxidation-reduction image-forming combination upon processing.
- a preferred concentration of photographic silver halide is within the range of 0.01 to 10 moles of photographic silver halide per mole of organic silver salt oxidizing agent, such as per mole of silver behenate, in the photothermographic material.
- Other photosensitive silver salts are useful in combination with the photographic silver halide if desired.
- Preferred photographic silver halides are silver chloride, silver bromide, silver bromoiodide, silver chlorobromoiodide and mixtures of these silver halides. Very fine grain photographic silver halide is especially useful.
- Migration imaging processes typically involve the arrangement of particles on a softenable medium.
- the medium which is solid and impermeable at room temperature, is softened with heat or solvents to permit particle migration in an imagewise pattern.
- migration imaging can be used to form a xeroprinting master element.
- a monolayer of photosensitive particles is placed on the surface of a layer of polymeric material which is in contact with a conductive layer.
- the element is subjected to imagewise exposure which softens the polymeric material and causes migration of particles where such softening occurs (i.e., image areas).
- image areas can be charged, developed, and transferred to paper.
- Another type of migration imaging technique utilizes a solid migration imaging element having a substrate and a layer of softenable material with a layer of photosensitive marking material deposited at or near the surface of the softenable layer.
- a latent image is formed by electrically charging the member and then exposing the element to an imagewise pattern of light to discharge selected portions of the marking material layer.
- the entire softenable layer is then made permeable by application of the marking material, heat or a solvent, or both.
- the portions of the marking material which retain a differential residual charge due to light exposure will then migrate into the softened layer by electrostatic force.
- An imagewise pattern may also be formed with colorant particles in a solid imaging element by establishing a density differential (e.g., by particle agglomeration or coalescing) between image and non-image areas.
- colorant particles are uniformly dispersed and then selectively migrated so that they are dispersed to varying extents without changing the overall quantity of particles on the element.
- Another migration imaging technique involves heat development, as described by R. M. Schaffert, Electrophotography , (Second Edition, Focal Press, 1980), pp. 44-47 and U.S. Patent 3,254,997.
- an electrostatic image is transferred to a solid imaging element, having colloidal pigment particles dispersed in a heat-softenable resin film on a transparent conductive substrate. After softening the film with heat, the charged colloidal particles migrate to the oppositely charged image. As a result, image areas have an increased particle density, while the background areas are less dense.
- laser toner fusion which is a dry electrothermographic process
- uniform dry powder toner depositions on non-photosensitive films, papers, or lithographic printing plates are imagewise exposed with high power (0.2-0.5 W) laser diodes thereby, "tacking" the toner particles to the substrate(s).
- the toner layer is made, and the non-imaged toner is removed, using such techniques as electrographic "magnetic brush” technology similar to that found in copiers.
- a final blanket fusing step may also be needed, depending on the exposure levels.
- imaging elements which employ an antistatic layer are dye-receiving elements used in thermal dye transfer systems.
- Thermal dye transfer systems are commonly used to obtain prints from pictures which have been generated electronically from a color video camera. According to one way of obtaining such prints, an electronic picture is first subjected to color separation by color filters. The respective color-separated images are then converted into electrical signals. These signals are then operated on to produce cyan, magenta and yellow electrical signals. These signals are then transmitted to a thermal printer. To obtain the print, a cyan, magenta or yellow dye-donor element is placed face-to-face with a dye-receiving element. The two are then inserted between a thermal printing head and a platen roller. A line-type thermal printing head is used to apply heat from the back of the dye-donor sheet.
- the thermal printing head has many heating elements and is heated up sequentially in response to the cyan, magenta and yellow signals. The process is then repeated for the other two colors. A color hard copy is thus obtained which corresponds to the original picture viewed on a screen. Further details of this process and an apparatus for carrying it out are described in U.S. Patent No. 4,621,271.
- Another type of image-forming process in which the imaging element can make use of an electrically-conductive layer is a process employing an imagewise exposure to electric current of a dye-forming electrically-activatable recording element to thereby form a developable image followed by formation of a dye image, typically by means of thermal development.
- Dye-forming electrically activatable recording elements and processes are well known and are described in such patents as U.S. 4,343,880 and 4,727,008.
- the image-forming layer can be any of the types of image-forming layers described above, as well as any other image-forming layer known for use in an imaging element.
- the imaging elements of the present invention at least one electrically-conductive which comprises polyaniline styrene sulfonic acid in effective amount to provide antistatic properties to the electrically-conductive layer.
- Binders useful in antistatic layers containing polyaniline styrene sulfonic acid include: water-soluble polymers such as gelatin, gelatin derivatives, maleic acid anhydride copolymers; cellulose compounds such as carboxymethyl cellulose, hydroxyethyl cellulose, cellulose acetate butyrate, diacetyl cellulose or triacetyl cellulose; synthetic hydrophilic polymers such as polyvinyl alcohol, poly-N-vinylpyrrolidone, acrylic acid copolymers, polyacrylamides, their derivatives and partially hydrolyzed products, vinyl polymers and copolymers such as polyvinyl acetate and polyacrylate acid esters; derivatives of the above polymers; and other synthetic resins.
- water-soluble polymers such as gelatin, gelatin derivatives, maleic acid anhydride copolymers
- cellulose compounds such as carboxymethyl cellulose, hydroxyethyl cellulose, cellulose acetate butyrate, diacetyl cellulose or tri
- Suitable binders include aqueous emulsions of addition-type polymers and interpolymers prepared from ethylenically unsaturated monomers such as acrylates including acrylic acid, methacrylates including methacrylic acid, acrylamides and methacrylamides, itaconic acid and its half-esters and diesters, styrenes including substituted styrenes, acrylonitrile and methacrylonitrile, vinyl acetates, vinyl ethers, vinyl and vinylidene halides, olefins, and aqueous dispersions of polyurethanes or polyesterionomers.
- acrylates including acrylic acid, methacrylates including methacrylic acid, acrylamides and methacrylamides, itaconic acid and its half-esters and diesters
- styrenes including substituted styrenes
- acrylonitrile and methacrylonitrile vinyl acetates
- vinyl ethers vinyl
- the preparation of the poly(aniline/polystyrene sulfonic acid) were made in situ by oxidative polymerization of aniline in aqueous solution in the presence of poly(styrene sulfonic acid) using ammonium peroxodisulfate as the oxidant.
- the conductive coatings were immersed in room-temperature baths of developer (C-41 developer, Eastman Kodak) for 15 seconds. They were then rinsed for 5 seconds in deionized water and left to dry at room temperature. The samples were visually inspected for evidence of hue shift, and the surface resistivity was again measured.
- developer C-41 developer, Eastman Kodak
- the table below includes information concerning the total dry coverage of the conductive film, and the portion (weight %) of the film comprising the polyaniline-styrene sulfonic acid of this invention.
- the examples demonstrate the wide range of polymeric and non-polymeric binders which may be successfully used in combination with polyaniline-styrene-sulfonic acid. In addition, they demonstrate the potential usefulness of various classes of crosslinkers in combination with such binders for improved chemical resistance.
- coatings such as those described here may be overcoated with materials known in the art; for example, polyalkylacrylates, methacrylates or the like, polyurethanes, cellulose esters, styrene-containing polymers, etc. Such an overcoat may be preferred in the harsher conditions (high temperature and long times) of an actual photographic processing event.
- the use of polyaniline styrene sulfonic acid in an electrically-conductive layer layer in imaging elements overcomes many of the difficulties that have heretofore been encountered in the prior art.
- the use of the polyaniline styrene sulfonic acid provides a transparent electrically-conductive layer which is process surviving and can be manufactured at a reasonable cost.
- the aniline may be a substituted aniline.
- the electrically-conductive layer is resistant to the effects of humidity change that is durable and abrasion resistant, thereby eliminating the need of an overcoat layer on a photographic imaging element.
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Abstract
Imaging element, such as photographic
electrostatographic thermal imaging elements are
comprised of a support, an imaging-forming layer, and a
transparent electrically-conductive layer which
includes an effective amount of polyaniline styrene
sulfonic acid. In a preferred embodiment, the
polyaniline styrene sulfonic acid is dispersed in a
binder.
Description
The present invention relates in general to
imaging elements, such as photographic,
electrostatographic, inkjet and thermal imaging
elements, and in particular to imaging elements
comprising a support, an image-forming layer and a
transparent electrically-conductive layer. More
specifically, this invention relates to the preparation
of water-soluble blends of polyaniline complexes of
poly(styrene sulfonic acid) or poly(styrene-co-styrene
sulfonic acid) with other polymers that can form
conductive films that are sufficiently transparent for
photographic applications, and retain their
conductivity after photographic processing with or
without the use of a protective overcoat layer.
Problems associated with the formation and
discharge of electrostatic charge during the
manufacture and utilization of photographic film and
paper have been recognized for many years by the
photographic industry. The accumulation of charge on
film or paper surfaces leads to the attraction of dust,
which can produce physical defects. The discharge of
accumulated charge during or after the application of
the sensitized emulsion layer(s) can produce irregular
fog patterns or "static marks" in the emulsion. The
severity of static problems has been exacerbated
greatly by increases in the sensitivity of new
emulsions, increases in coating machine speeds, and
increases in post-coating drying efficiency. The
charge generated during the coating process results
primarily from the tendency of webs of high dielectric
polymeric film base to charge during winding and
unwinding operations (unwinding static), during
transport through the coating machines (transport
static), and during post-coating operations such as
slitting and spooling. Static charge can also be
generated during the use of the finished photographic
film product. In an automatic camera, the winding of
roll film out of and back into the film cassette,
especially in a low relative humidity environment, can
result in static charging. Similarly, high-speed
automated film processing can result in static charge
generation. Sheet films are especially subject to
static charging during removal from light-tight
packaging (e.g., x-ray films).
It is generally known that electrostatic
charge can be dissipated effectively by incorporating
one or more electrically-conductive "antistatic" layers
into the film structure. Antistatic layers can be
applied to one or to both sides of the film base as
subbing layers either beneath or on the side opposite
to the light-sensitive silver halide emulsion layers.
An antistatic layer can alternatively be applied as an
outer coated layer either over the emulsion layers or
on the side of the film base opposite to the emulsion
layers or both. For some applications, the antistatic
agent can be incorporated into the emulsion layers.
Alternatively, the antistatic agent can be directly
incorporated into the film base itself.
A wide variety of electrically-conductive
materials can be incorporated into antistatic layers to
produce a wide range of conductivities. Most of the
traditional antistatic systems for photographic
applications employ ionic conductors. Charge is
transferred in ionic conductors by the bulk diffusion
of charged species through an electrolyte. Antistatic
layers containing simple inorganic salts, alkali metal
salts of surfactants, ionic conductive polymers,
polymeric electrolytes containing alkali metal salts,
and colloidal metal oxide sols (stabilized by metal
salts) have been described previously. The
conductivities of these ionic conductors are typically
strongly dependent on the temperature and relative
humidity in their environment. At low humidities and
temperatures, the diffusional mobilities of the ions
are greatly reduced and conductivity is substantially
decreased. At high humidities, antistatic backcoatings
often absorb water, swell, and soften. In roll film,
this results in adhesion of the backcoating to the
emulsion side of the film. Also, many of the inorganic
salts, polymeric electrolytes, and low molecular weight
surfactants used are water-soluble and are leached out
of the antistatic layers during processing, resulting
in a loss of antistatic function.
Colloidal metal oxide sols which exhibit
ionic or electronic conductivity when included in
antistatic layers are often used in imaging elements.
Typically, alkali metal salts or anionic surfactants
are used to stabilize these sols. A thin antistatic
layer consisting of a gelled network of colloidal metal
oxide particles (e.g., silica, antimony pentoxide,
alumina, titania, stannic oxide, zirconia) with an
optional polymeric binder to improve adhesion to both
the support and overlying emulsion layers has been
disclosed in EP 250,154. An optional ambifunctional
silane or titanate coupling agent can be added to the
gelled network to improve adhesion to overlying
emulsion layers (e.g., EP 301,827; U.S. Patent No.
5,204,219) along with an optional alkali metal
orthosilicate to minimize loss of conductivity by the
gelled network when it is overcoated with gelatin-containing
layers (U.S. Patent No. 5,236,818). Also,
it has been pointed out that coatings containing
colloidal metal oxides (e.g., antimony pentoxide,
alumina, tin oxide, indium oxide) and colloidal silica
with an organopolysiloxane binder afford enhanced
abrasion resistance as well as provide antistatic
function (U.S. Patent Nos. 4,442,168 and 4,571,365).
Antistatic systems employing electronic
conductors have also been described. Because the
conductivity depends predominantly on electronic
mobilities rather than ionic mobilities, the observed
electronic conductivity is independent of relative
humidity and only slightly influenced by the ambient
temperature. Antistatic layers have been described
which contain conjugated polymers, conductive carbon
particles or semiconductive inorganic particles.
Trevoy (U.S. Patent 3,245,833) has taught the
preparation of conductive coatings containing
semiconductive silver or copper iodide dispersed as
particles less than 0.1 µm in size in an insulating
film-forming binder, exhibiting a surface resistivity
of 102 to 1011 ohms per scare . The conductivity of
these coatings is substantially independent of the
relative humidity. Also, the coatings are relatively
clear and sufficiently transparent to permit their use
as antistatic coatings for photographic film. However,
if a coating containing copper or silver iodides was
used as a subbing layer on the same side of the film
base as the emulsion, Trevoy found (U.S. Patent
3,428,451) that it was necessary to overcoat the
conductive layer with a dielectric, water-impermeable
barrier layer to prevent migration of semiconductive
salt into the silver halide emulsion layer during
processing. Without the barrier layer, the
semiconductive salt could interact deleteriously with
the silver halide layer to form fog and a loss of
emulsion sensitivity. Also, without a barrier layer,
the semiconductive salts are solubilized by processing
solutions, resulting in a loss of antistatic function.
Another semiconductive material has been
disclosed by Nakagiri and Inayama (U.S. Patent
4,078,935) as being useful in antistatic layers for
photographic applications. Transparent, binderless,
electrically semiconductive metal oxide thin films were
formed by oxidation of thin metal films which had been
vapor deposited onto film base. Suitable transition
metals include titanium, zirconium, vanadium, and
niobium. The microstructure of the thin metal oxide
films is revealed to be non-uniform and discontinuous,
with an "island" structure almost "particulate" in
nature. The surface resistivity of such semiconductive
metal oxide thin films is independent of relative
humidity and reported to range from 105 to 109 ohms per
square. However, the metal oxide thin films are
unsuitable for photographic applications since the
overall process used to prepare these thin films is
complicated and costly, abrasion resistance of these
thin films is low, and adhesion of these thin films to
the base is poor.
A highly effective antistatic layer
incorporating an "amorphous" semiconductive metal oxide
has been disclosed by Guestaux (U.S. Patent 4,203,769).
The antistatic layer is prepared by coating an aqueous
solution containing a colloidal gel of vanadium
pentoxide onto a film base. The colloidal vanadium
pentoxide gel typically consists of entangled, high
aspect ratio, flat ribbons 50-100 Å wide, 10 Å thick,
and 1,000-10,000 Å long. These ribbons stack flat in
the direction perpendicular to the surface when the gel
is coated onto the film base. This results in
electrical conductivities for thin films of vanadium
pentoxide gels (1 Ω-1cm-1) which are typically three
orders of magnitude greater than is observed for
similar thickness films containing crystalline vanadium
pentoxide particles. In addition, low surface
resistivities can be obtained with very low vanadium
pentoxide coverages. This results in low optical
absorption and scattering losses. Also, the thin films
are highly adherent to appropriately prepared film
bases. However, vanadium pentoxide is soluble at high
pH and must be overcoated with a non-permeable,
hydrophobic barrier layer in order to survive
processing. When used with a conductive subbing layer,
the barrier layer must be coated with a hydrophilic
layer to promote adhesion to emulsion layers above.
(See Anderson et al, U.S. Patent 5,006,451.)
Conductive fine particles of crystalline
metal oxides dispersed with a polymeric binder have
been used to prepare optically transparent, humidity
insensitive, antistatic layers for various imaging
applications. Many different metal oxides -- such as
ZnO, TiO2, ZrO2, SnO2, Al2O3, In2O3, SiO2, MgO, BaO,
MoO3 and V2O5 -- are alleged to be useful as antistatic
agents in photographic elements or as conductive agents
in electrostatographic elements in such patents as U.S.
4,275,103, 4,394,441, 4,416,963, 4,418,141, 4,431,764,
4,495,276, 4,571,361, 4,999,276 and 5,122,445.
However, many of these oxides do not provide acceptable
performance characteristics in these demanding
environments. Preferred metal oxides are antimony
doped tin oxide, aluminum doped zinc oxide, and niobium
doped titanium oxide. Surface resistivities are
reported to range from 106-109 ohms per square for
antistatic layers containing the preferred metal
oxides. In order to obtain high electrical
conductivity, a relatively large amount (0.1-10 g/m2)
of metal oxide must be included in the antistatic
layer. This results in decreased optical transparency
for thick antistatic coatings. The high values of
refractive index (>2.0) of the preferred metal oxides
necessitates that the metal oxides be dispersed in the
form of ultrafine (<0.1 µm) particles in order to
minimize light scattering (haze) by the antistatic
layer.
Antistatic layers comprising electro-conductive
ceramic particles, such as particles of TiN,
NbB2, TiC, LaB6 or MoB, dispersed in a binder such as a
water-soluble polymer or solvent-soluble resin are
described in Japanese Kokai No. 4/55492, published
February 24, 1992.
Fibrous conductive powders comprising
antimony-doped tin oxide coated onto non-conductive
potassium titanate whiskers have been used to prepare
conductive layers for photographic and electrographic
applications. Such materials are disclosed, for
example, in U.S. Patents, 4,845,369 and 5,116,666.
Layers containing these conductive whiskers dispersed
in a binder reportedly provide improved conductivity at
lower volumetric concentrations than other conductive
fine particles as a result of their higher aspect
ratio. However, the benefits obtained as a result of
the reduced volume percentage requirements are offset
by the fact that these materials are relatively large
in size such as 10 to 20 micrometers in length, and
such large size results in increased light scattering
and hazy coatings.
Use of a high volume percentage of conductive
particles in an electro-conductive coating to achieve
effective antistatic performance can result in reduced
transparency due to scattering losses and in the
formation of brittle layers that are subject to
cracking and exhibit poor adherence to the support
material. It is thus apparent that it is extremely
difficult to obtain non-brittle, adherent, highly
transparent, colorless electro-conductive coatings with
humidity-independent process-surviving antistatic
performance.
The requirements for antistatic layers in
silver halide photographic films are especially
demanding because of the stringent optical
requirements. Other types of imaging elements such as
photographic papers and thermal imaging elements also
frequently require the use of an antistatic layer but,
generally speaking, these imaging elements have less
stringent requirements.
Electrically-conductive layers are also
commonly used in imaging elements for purposes other
than providing static protection. Thus, for example,
in electrostatographic imaging it is well known to
utilize imaging elements comprising a support, an
electrically-conductive layer that serves as an
electrode, and a photoconductive layer that serves as
the image-forming layer. Electrically-conductive
agents utilized as antistatic agents in photographic
silver halide imaging elements are often also useful in
the electrode layer of electrostatographic imaging
elements.
As indicated above, the prior art on
electrically-conductive layers in imaging elements is
extensive and a very wide variety of different
materials have been proposed for use as the
electrically-conductive agent. There is still,
however, a critical need in the art for improved
electrically-conductive layers which are useful in a
wide variety of imaging elements, which can be
manufactured at reasonable cost, which are resistant to
the effects of humidity change, which are durable and
abrasion-resistant, which are effective at low
coverage, which are adaptable to use with transparent
imaging elements, which do not exhibit adverse
sensitometric or photographic effects, and which are
substantially insoluble in solutions with which the
imaging element typically comes in contact, for
example, the aqueous alkaline developing solutions used
to process silver halide photographic films.
It is toward the objective of providing
improved electrically-conductive layers that more
effectively meet the diverse needs of imaging elements
-- especially of silver halide photographic films but
also of a wide range of other imaging elements -- than
those of the prior art that the present invention is
directed.
In accordance with this invention, an imaging
element for use in an imaging-forming process comprises
a support, an image-forming layer, and a tranparent
electrically-conductive layer comprising polyaniline
styrene sulfonic acid.
In a preferred embodiment of this invention,
the transparent electrically-conductive layer includes
the polyaniline styrene sulfonic acid dispersed in a
film-forming binder.
The imaging elements of this invention can be
of many different types depending on the particular use
for which they are intended. Such elements include,
for example, photographic, electrostatographic,
photothermographic, migration, electrothermographic,
dielectric recording and thermal-dye-transfer imaging
elements.
Photographic elements which can be provided
with an antistatic layer in accordance with this
invention can differ widely in structure and
composition. For example, they can vary greatly in
regard to the type of support, the number and
composition of the image-forming layers, and the kinds
of auxiliary layers that are included in the elements.
In particular, the photographic elements can be still
films, motion picture films, x-ray films, graphic arts
films, paper prints or microfiche. They can be black-and-white
elements, color elements adapted for use in a
negative-positive process, or color elements adapted
for use in a reversal process.
Photographic elements can comprise any of a
wide variety of supports. Typical supports include
cellulose nitrate film, cellulose acetate film,
poly(vinyl acetal) film, polystyrene film, poly(ethylene
terephthalate) film, poly(ethylene
naphthalate) film, polycarbonate film, glass, metal,
paper, polymer-coated paper, and the like. The image-forming
layer or layers of the element typically
comprise a radiation-sensitive agent, e.g., silver
halide, dispersed in a hydrophilic water-permeable
colloid. Suitable hydrophilic vehicles include both
naturally-occurring substances such as proteins, for
example, gelatin, gelatin derivatives, cellulose
derivatives, polysaccharides such as dextran, gum
arabic, and the like, and synthetic polymeric
substances such as water-soluble polyvinyl compounds
like poly(vinylpyrrolidone), acrylamide polymers, and
the like. A particularly common example of an image-forming
layer is a gelatin-silver halide emulsion
layer.
In electrostatography an image comprising a
pattern of electrostatic potential (also referred to as
an electrostatic latent image) is formed on an
insulative surface by any of various methods. For
example, the electrostatic latent image may be formed
electrophotographically (i.e., by imagewise radiation-induced
discharge of a uniform potential previously
formed on a surface of an electrophotographic element
comprising at least a photoconductive layer and an
electrically-conductive substrate), or it may be formed
by dielectric recording (i.e., by direct electrical
formation of a pattern of electrostatic potential on a
surface of a dielectric material). Typically, the
electrostatic latent image is then developed into a
toner image by contacting the latent image with an
electrographic developer (if desired, the latent image
can be transferred to another surface before
development). The resultant toner image can then be
fixed in place on the surface by application of heat
and/or pressure or other known methods (depending upon
the nature of the surface and of the toner image) or
can be transferred by known means to another surface,
to which it then can be similarly fixed.
In many electrostatographic imaging
processes, the surface to which the toner image is
intended to be ultimately transferred and fixed is the
surface of a sheet of plain paper or, when it is
desired to view the image by transmitted light (e.g.,
by projection in an overhead projector), the surface of
a transparent film sheet element.
In electrostatographic elements, the
electrically-conductive layer can be a separate layer,
a part of the support layer or the support layer.
There are many types of conducting layers known to the
electrostatographic art, the most common being listed
below:
Conductive layers (d), (e) and (f) can be
transparent and can be employed where transparent
elements are required, such as in processes where the
element is to be exposed from the back rather than the
front or where the element is to be used as a
transparency.
Thermally processable imaging elements,
including films and papers, for producing images by
thermal processes are well known. These elements
include thermographic elements in which an image is
formed by imagewise heating the element. Such elements
are described in, for example, Research Disclosure,
June 1978, Item No. 17029; U.S. Patent No. 3,457,075;
U.S. Patent No. 3,933,508; and U.S. Patent No.
3,080,254.
Photothermographic elements typically
comprise an oxidation-reduction image-forming
combination which contains an organic silver salt
oxidizing agent, preferably a silver salt of a long-chain
fatty acid. Such organic silver salt oxidizing
agents are resistant to darkening upon illumination.
Preferred organic silver salt oxidizing agents are
silver salts of long-chain fatty acids containing 10 to
30 carbon atoms. Examples of useful organic silver
salt oxidizing agents are silver behenate, silver
stearate, silver oleate, silver laurate, silver
hydroxystearate, silver caprate, silver myristate and
silver palmitate. Combinations of organic silver salt
oxidizing agents are also useful. Examples of useful
silver salt oxidizing agents which are not silver salts
of long-chain fatty acids include, for example, silver
benzoate and silver benzotriazole.
Photothermographic elements also comprise a
photosensitive component which consists essentially of
photographic silver halide. In photothermographic
materials it is believed that the latent image silver
from the silver halide acts as a catalyst for the
oxidation-reduction image-forming combination upon
processing. A preferred concentration of photographic
silver halide is within the range of 0.01 to 10 moles
of photographic silver halide per mole of organic
silver salt oxidizing agent, such as per mole of silver
behenate, in the photothermographic material. Other
photosensitive silver salts are useful in combination
with the photographic silver halide if desired.
Preferred photographic silver halides are silver
chloride, silver bromide, silver bromoiodide, silver
chlorobromoiodide and mixtures of these silver halides.
Very fine grain photographic silver halide is
especially useful.
Migration imaging processes typically involve
the arrangement of particles on a softenable medium.
Typically, the medium, which is solid and impermeable
at room temperature, is softened with heat or solvents
to permit particle migration in an imagewise pattern.
As disclosed in R. W. Gundlach, "Xeroprinting
Master with Improved Contrast Potential", Xerox
Disclosure Journal, Vol. 14, No. 4, July/August 1984,
pages 205-06, migration imaging can be used to form a
xeroprinting master element. In this process, a
monolayer of photosensitive particles is placed on the
surface of a layer of polymeric material which is in
contact with a conductive layer. After charging, the
element is subjected to imagewise exposure which
softens the polymeric material and causes migration of
particles where such softening occurs (i.e., image
areas). When the element is subsequently charged and
exposed, the image areas (but not the non-image areas)
can be charged, developed, and transferred to paper.
Another type of migration imaging technique,
disclosed in U.S. Patent No. 4,536,457 to Tam, U.S.
Patent No. 4,536,458 to Ng, and U.S. Patent No.
4,883,731 to Tam et al, utilizes a solid migration
imaging element having a substrate and a layer of
softenable material with a layer of photosensitive
marking material deposited at or near the surface of
the softenable layer. A latent image is formed by
electrically charging the member and then exposing the
element to an imagewise pattern of light to discharge
selected portions of the marking material layer. The
entire softenable layer is then made permeable by
application of the marking material, heat or a solvent,
or both. The portions of the marking material which
retain a differential residual charge due to light
exposure will then migrate into the softened layer by
electrostatic force.
An imagewise pattern may also be formed with
colorant particles in a solid imaging element by
establishing a density differential (e.g., by particle
agglomeration or coalescing) between image and non-image
areas. Specifically, colorant particles are
uniformly dispersed and then selectively migrated so
that they are dispersed to varying extents without
changing the overall quantity of particles on the
element.
Another migration imaging technique involves
heat development, as described by R. M. Schaffert,
Electrophotography, (Second Edition, Focal Press,
1980), pp. 44-47 and U.S. Patent 3,254,997. In this
procedure, an electrostatic image is transferred to a
solid imaging element, having colloidal pigment
particles dispersed in a heat-softenable resin film on
a transparent conductive substrate. After softening
the film with heat, the charged colloidal particles
migrate to the oppositely charged image. As a result,
image areas have an increased particle density, while
the background areas are less dense.
An imaging process known as "laser toner
fusion", which is a dry electrothermographic process,
is also of significant commercial importance. In this
process, uniform dry powder toner depositions on non-photosensitive
films, papers, or lithographic printing
plates are imagewise exposed with high power (0.2-0.5
W) laser diodes thereby, "tacking" the toner particles
to the substrate(s). The toner layer is made, and the
non-imaged toner is removed, using such techniques as
electrographic "magnetic brush" technology similar to
that found in copiers. A final blanket fusing step may
also be needed, depending on the exposure levels.
Another example of imaging elements which
employ an antistatic layer are dye-receiving elements
used in thermal dye transfer systems.
Thermal dye transfer systems are commonly
used to obtain prints from pictures which have been
generated electronically from a color video camera.
According to one way of obtaining such prints, an
electronic picture is first subjected to color
separation by color filters. The respective color-separated
images are then converted into electrical
signals. These signals are then operated on to produce
cyan, magenta and yellow electrical signals. These
signals are then transmitted to a thermal printer. To
obtain the print, a cyan, magenta or yellow dye-donor
element is placed face-to-face with a dye-receiving
element. The two are then inserted between a thermal
printing head and a platen roller. A line-type thermal
printing head is used to apply heat from the back of
the dye-donor sheet. The thermal printing head has
many heating elements and is heated up sequentially in
response to the cyan, magenta and yellow signals. The
process is then repeated for the other two colors. A
color hard copy is thus obtained which corresponds to
the original picture viewed on a screen. Further
details of this process and an apparatus for carrying
it out are described in U.S. Patent No. 4,621,271.
Another type of image-forming process in
which the imaging element can make use of an
electrically-conductive layer is a process employing an
imagewise exposure to electric current of a dye-forming
electrically-activatable recording element to thereby
form a developable image followed by formation of a dye
image, typically by means of thermal development. Dye-forming
electrically activatable recording elements and
processes are well known and are described in such
patents as U.S. 4,343,880 and 4,727,008.
In the imaging elements of this invention,
the image-forming layer can be any of the types of
image-forming layers described above, as well as any
other image-forming layer known for use in an imaging
element.
All of the imaging processes described
hereinabove, as well as many others, have in common the
use of an electrically-conductive layer as an electrode
or as an antistatic layer. The requirements for a
useful electrically-conductive layer in an imaging
environment are extremely demanding and thus the art
has long sought to develop improved electrically-conductive
layers exhibiting the necessary combination
of physical, optical and chemical properties.
As described hereinabove, the imaging
elements of the present invention at least one
electrically-conductive which comprises polyaniline
styrene sulfonic acid in effective amount to provide
antistatic properties to the electrically-conductive
layer.
Binders useful in antistatic layers
containing polyaniline styrene sulfonic acid include:
water-soluble polymers such as gelatin, gelatin
derivatives, maleic acid anhydride copolymers;
cellulose compounds such as carboxymethyl cellulose,
hydroxyethyl cellulose, cellulose acetate butyrate,
diacetyl cellulose or triacetyl cellulose; synthetic
hydrophilic polymers such as polyvinyl alcohol, poly-N-vinylpyrrolidone,
acrylic acid copolymers,
polyacrylamides, their derivatives and partially
hydrolyzed products, vinyl polymers and copolymers such
as polyvinyl acetate and polyacrylate acid esters;
derivatives of the above polymers; and other synthetic
resins. Other suitable binders include aqueous
emulsions of addition-type polymers and interpolymers
prepared from ethylenically unsaturated monomers such
as acrylates including acrylic acid, methacrylates
including methacrylic acid, acrylamides and
methacrylamides, itaconic acid and its half-esters and
diesters, styrenes including substituted styrenes,
acrylonitrile and methacrylonitrile, vinyl acetates,
vinyl ethers, vinyl and vinylidene halides, olefins,
and aqueous dispersions of polyurethanes or
polyesterionomers.
The preparation of the poly(aniline/polystyrene
sulfonic acid) were made in situ by oxidative
polymerization of aniline in aqueous solution in the
presence of poly(styrene sulfonic acid) using ammonium
peroxodisulfate as the oxidant.
In a typical preparation, 0.99 g (1 ml, 10.6
mmoles) of aniline were added to 50 ml's of a solution
of 8 weight percent polystyrene sulfonic acid in water.
The solution was chilled and stirred in an ice bath. A
solution of 1.208 g (5.3 mmoles) of (NH4)2S2O8 in 50 mL
of water was added dropwise over a period of several
hours. The reaction was allowed to run to completion
overnight at room temperature. The dark green solution
of poly(aniline/polystyrene sulfonic acid) complex
obtained in this fashion was placed in a SPECTRA/POR
dialysis membrane tubing with a molecular weight cutoff
of 12,000-14,000 and was dialyzed against continuously
replenished distilled water for approximately 8 hours.
Coatings of poly(aniline/poly-styrene sulfonic acid)
prepared in this fashion are transparent in suitable
photographic applications. Non-dialyzed comparable
materials give hazy coatings.
Several conductive layers were formed by
coating combinations of polyaniline-styrene sulfonic
acid and various film-forming binders. Surface
electrical resistivity was measured with a Trek Model
150 surface resistivity meter (Trek, Inc., Medina,
N.Y.) according to ASTM standard method D257-78.
In order to test resistance to typical
photographic processing chemistries, the conductive
coatings were immersed in room-temperature baths of
developer (C-41 developer, Eastman Kodak) for 15
seconds. They were then rinsed for 5 seconds in
deionized water and left to dry at room temperature.
The samples were visually inspected for evidence of hue
shift, and the surface resistivity was again measured.
The examples below were all coated from
aqueous solutions of polyaniline-styrene sulfonic
acid/binder systems onto polyethylene terephthalate
which was subbed with a terpolymer of
acrylonitrile/vinylidene chloride/acrylic acid as is
well known in the art. Other subbing layers or corona
discharge treatment (CDT) may also be used with similar
results. In addition, other support materials could be
chosen, including paper, resin coated paper, cellulose
triacetate, PEN, etc. The coatings were made either by
wound wire rod or x-hopper coating, but any commonly
known coating method could be employed, including
gravure, etc. Surfactants, defoamers, leveling agents,
matte particles, lubricants, crosslinkers and the like
may be added to such coatings as deemed necessary by
the coating method or end use of such coatings. The
coatings were thoroughly dried at 100 °C.
The table below includes information
concerning the total dry coverage of the conductive
film, and the portion (weight %) of the film comprising
the polyaniline-styrene sulfonic acid of this
invention.
Binder | Wt% Pani- PSSA | Total dry coverage, g/m2 | log surface resistivity (Ω) before C-41 immersion | log surface resistivity (Ω) after C-41 immersion | Color shift after C-41 immersion |
Polymer A | 10 | 1.1 | 8.8 | 8.6 | none |
Polymer B | 10 | 1.1 | 8.8 | 9.5 | blue |
Polymer C | 10 | 1.1 | 8.8 | 9.3 | blue |
Polymer D | 10 | 3 | 8.2 | 9.3 | blue-purple |
Polymer D with 10% Cymel 303 | 10 | 1.1 | 9.6 | 9.1 | none |
Polymer D with 10% EKL-4299 | 10 | 1.1 | 9.6 | 10.6 | greener |
Polymer D with 10% XL-29E | 10 | 1.1 | 9.3 | 9.9 | gray-blue |
Polymer E | 10 | 1.7 | 8.0 | 8.0 | less green (more colorless) |
Ludox SK | 10 | 1.1 | 9 | 7.4 | blue |
Polymer A: Terpolymer of Acrylonitrile/vinylidene
chloride/acrylic acid (15/78/7) Polymer B: Copolymer of n-Butyl acrylate/glycidyl methacrylate (70/30) Polymer C: Copolymer of methyl methacrylate/hydroxyethyl methacrylate (90/10) Polymer D: Commercially available sulfonated polyester AQ55, Eastman Chemicals Polymer E: Commercially available styrene acrylic latex copolymer BF Goodrich Carboset GA 1931 Ludox SK: Commercially available colloidal silica, DuPont Cymel 303: Commercially available melamine-formaldehyde crosslinker, American Cyanamid EKL-4299: Commercially available cycloaliphatic epoxy resin, Union Carbide XL-29E: Commercially available aliphatic carbodiimide, Union Carbide Ucarlink |
The examples demonstrate the wide range of
polymeric and non-polymeric binders which may be
successfully used in combination with polyaniline-styrene-sulfonic
acid. In addition, they demonstrate
the potential usefulness of various classes of
crosslinkers in combination with such binders for
improved chemical resistance.
For improved abrasion resistance and chemical
resistance, coatings such as those described here may
be overcoated with materials known in the art; for
example, polyalkylacrylates, methacrylates or the like,
polyurethanes, cellulose esters, styrene-containing
polymers, etc. Such an overcoat may be preferred in
the harsher conditions (high temperature and long
times) of an actual photographic processing event.
As hereinabove described, the use of
polyaniline styrene sulfonic acid in an electrically-conductive
layer layer in imaging elements overcomes
many of the difficulties that have heretofore been
encountered in the prior art. In particular, the use
of the polyaniline styrene sulfonic acid provides a
transparent electrically-conductive layer which is
process surviving and can be manufactured at a
reasonable cost. The aniline may be a substituted
aniline. The electrically-conductive layer is
resistant to the effects of humidity change that is
durable and abrasion resistant, thereby eliminating the
need of an overcoat layer on a photographic imaging
element.
Claims (9)
- An imaging element for use in an image-forming process; said imaging element comprising a support, an image-forming layer; and a transparent electrically-conductive layer comprising polyaniline styrene sulfonic acid.
- The imaging element according to claim 1, wherein the polyaniline styrene sulfonic acid is dispersed in a film-forming binder.
- The imaging element according to claim 2, wherein the film-forming binder is gelatin.
- The imaging element according to claim 2, wherein the film-forming binder is a vinylidene chloride-based terpolymer latex.
- The imaging element according to claim 1, wherein the polyaniline styrene sulfonic acid includes substituted aniline.
- A transparent coating composition for use in an imaging element comprising:polyaniline styrene sulfonic acid dispersed in a film-forming binder.
- The transparent coating composition according to claim 6, wherein the film-forming binder is gelatin.
- The transparent coating composition according to claim 6, wherein the film-forming binder is a vinyliderie chloride-based terpolymer latex.
- The transparent coating composition according to claim 6, wherein the polyaniline styrene sulfonic acid includes substituted aniline.
Applications Claiming Priority (2)
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Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
GB2352512A (en) * | 1999-07-23 | 2001-01-31 | Toshiba Res Europ Ltd | A radiation probe and dectecting tooth decay |
WO2002065484A1 (en) * | 2001-02-09 | 2002-08-22 | E. I. Du Pont De Nemours And Company | Aqueous conductive dispersions of polyaniline having enhanced viscosity |
Citations (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3856530A (en) * | 1969-10-29 | 1974-12-24 | Agfa Gevaert | Photographic polyester film material comprising antistatic layer |
JPH0521824A (en) * | 1991-07-12 | 1993-01-29 | Mitsubishi Paper Mills Ltd | Photoelectric conversion element |
JPH0632845A (en) * | 1992-07-20 | 1994-02-08 | Showa Denko Kk | Production of electrically conductive high molecular complex material |
JPH08211555A (en) * | 1995-02-02 | 1996-08-20 | Konica Corp | Silver halide photographic sensitive material with antistatic layer |
EP0758671A2 (en) * | 1995-08-10 | 1997-02-19 | Eastman Kodak Company | Electrically conductive composition and elements containing solubilized polyaniline complex |
-
1997
- 1997-08-23 EP EP97202603A patent/EP0828184A1/en not_active Withdrawn
- 1997-09-03 JP JP23798697A patent/JPH1097027A/en active Pending
Patent Citations (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3856530A (en) * | 1969-10-29 | 1974-12-24 | Agfa Gevaert | Photographic polyester film material comprising antistatic layer |
JPH0521824A (en) * | 1991-07-12 | 1993-01-29 | Mitsubishi Paper Mills Ltd | Photoelectric conversion element |
JPH0632845A (en) * | 1992-07-20 | 1994-02-08 | Showa Denko Kk | Production of electrically conductive high molecular complex material |
JPH08211555A (en) * | 1995-02-02 | 1996-08-20 | Konica Corp | Silver halide photographic sensitive material with antistatic layer |
EP0758671A2 (en) * | 1995-08-10 | 1997-02-19 | Eastman Kodak Company | Electrically conductive composition and elements containing solubilized polyaniline complex |
Non-Patent Citations (4)
Title |
---|
DATABASE WPI Section Ch Week 9309, Derwent World Patents Index; Class A85, AN 93-072727, XP002049682 * |
DATABASE WPI Section Ch Week 9410, Derwent World Patents Index; Class A26, AN 94-080017, XP002049684 * |
DATABASE WPI Section Ch Week 9643, Derwent World Patents Index; Class A23, AN 96-429023, XP002049683 * |
DEFIEUW G ET AL: "THERMAL DYE SUBLIMATION TRANSFER", RESEARCH DISCLOSURE, no. 334, 1 February 1992 (1992-02-01), pages 155 - 159, XP000291266 * |
Cited By (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
GB2352512A (en) * | 1999-07-23 | 2001-01-31 | Toshiba Res Europ Ltd | A radiation probe and dectecting tooth decay |
GB2352512B (en) * | 1999-07-23 | 2002-03-13 | Toshiba Res Europ Ltd | A radiation probe and detecting tooth decay |
US8027709B2 (en) | 1999-07-23 | 2011-09-27 | Teraview Limited | Radiation probe and detecting tooth decay |
WO2002065484A1 (en) * | 2001-02-09 | 2002-08-22 | E. I. Du Pont De Nemours And Company | Aqueous conductive dispersions of polyaniline having enhanced viscosity |
Also Published As
Publication number | Publication date |
---|---|
JPH1097027A (en) | 1998-04-14 |
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