JPH11327085A - Image forming element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electrically conductive layer which endures against changes in humidity, which has durability and friction resistance, which does not give bad influences to sensitometry and which shows good adhesion and cohesion properties. SOLUTION: This image forming element consists of a supporting body, an image forming layer deposited on the supporting body, and an electrically conductive layer on the image forming layer. The conductive layer contains a film forming binder and acicular crystalline single phase conductive metal- contg. particles. The acicular crystalline single phase conductive metal-contg. particles have <=0.02 μm diameter and >=3:1 aspect ratio. The conductive layer is formed by using a polymer pulverized medium having <350 μm size, dispersing acicular particles in the medium to prepare a colloidal dispersion, mixing the colloidal dispersion and the film forming binder, applying the mixture on the supporting body, and drying the mixture.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention generally relates to a support,
It relates to an imaging element comprising one or more imaging layers and one or more transparent conductive layers. More specifically, the present invention comprises one or more sensitized silver halide emulsion layers and one or more conductive layers, wherein the conductive layers use a polymeric grinding media. Photographic elements and heat-processable imaging elements comprising needle-like metal-containing conductive microparticles dispersed as a colloidal dispersion in one or more film-forming binders.

[0002]

BACKGROUND OF THE INVENTION Problems associated with the generation and discharge of static charge during the manufacture and use of photographic films and papers have been recognized by the photographic industry for many years. The accumulation of charge on the surface of the film or paper makes transport of the support difficult and attracts dust and other physical properties that can cause fogging, desensitization, repellency spots during emulsion coating. May be defective. Discharge of the accumulated electrostatic charge during or after the application of the sensitized emulsion layer (s) may result in irregular fog patterns or static marks in the emulsion. The severity of the static problem was greatly exacerbated by the increased sensitivity of new emulsions, increased coater speeds, and increased post-coating drying efficiency. The charge generated during the coating process is
High dielectric constant polymers subject to triboelectric charging during winding and unwinding operations, during their transport through the coater, and during post-coating operations such as slitting, perforating, and spooling Attributable mainly to the film-based trend. Static charge can also be generated during use of the finished photographic product. In automatic cameras, especially in environments with low relative humidity, the photographic film can be rolled into the film cassette,
Repeating unwinding may then generate an electrostatic charge. The accumulation of charge on the film surface results in the attraction and adhesion of dust to the film, and may even result in static marking. Similarly,
High speed automated film processing equipment can generate static electricity that causes marking. During use in automated high-speed film cassette loaders, sheet films are particularly exposed to static charges (eg, X-ray films,
Graphic arts film etc.).

To eliminate the problems arising from electrostatic charging, a conductive antistatic layer is provided in the photographic element, for example,
As an undercoat layer, as an outermost layer located above the intermediate layer, especially the silver halide emulsion layer, on the opposite side of the support from the silver halide emulsion layer (s) or on both sides of the support There are various well-known methods that can be introduced as a backing layer to dissipate the accumulated electrostatic charge. A wide variety of conductive antistatic agents can be incorporated into the antistatic layer to produce a wide range of surface conductivity. Many traditional antistatic layers used in photographic elements use materials that exhibit excellent ionic conductivity. The prior art teaches simple inorganic salts, alkali metal salts of surfactants, alkali metal ion stabilized colloidal metal oxide sols, polyelectrolytes containing ionic conductive polymers or alkali metal salts. The conductivity of such ionic conductors generally depends strongly on the temperature and relative humidity of the surrounding environment. At lower relative humidities and temperatures, the diffusion mobilities of those charge-carrying ions are greatly reduced, and their overall conductivity is greatly reduced. In addition, at high relative humidity, the unprotected antistatic backing layer may absorb water, swell, and soften. This can result in adhesion (especially ferrotyping), especially in the case of roll films, and even some of the backing layer may be physically transferred to the emulsion side surface layer of the film (ie, blocking).

Electronic conductors, such as conjugated conductive polymers,
With the use of antistatic layers containing conductive carbon particles, crystalline semiconductor particles, amorphous semiconductive fibrils, and continuous semiconductive thin films, their conductivity is independent of relative humidity. Because they are only slightly affected by ambient temperature, they can dissipate electrostatic charges more effectively than ionic conductors. Among the various types of electronic conductors, conductive metal-containing particles, such as semiconductive metal oxides, are particularly effective when dispersed with a suitable polymeric film-forming binder. Binary metal oxides doped with suitable donor heteroatoms or containing oxygen deficiencies have been described as useful in antistatic layers for photographic elements, for example, in US Pat. , 2
No. 75,103, No. 4,416,963, No. 4,495,276, No.
No. 4,394,441, No. 4,418,141, No. 4,431,764,
No. 4,495,276, No. 4,571,361, No. 4,999,276
No. 5,122,445, No. 5,294,525, No. 5,38
Nos. 2,494 and 5,459,021. Preferred conductive metal oxides claimed are zinc oxide, titania, tin oxide, alumina, indium oxide,
Contains silica, magnesia, zirconia, barium oxide, molybdenum trioxide, tungsten trioxide, and vanadium pentoxide. Preferred doped conductive metal oxide particles are Sb-doped tin oxide, Al-doped zinc oxide,
And Nb-doped titania. Further preferred conductive ternary metal oxides are disclosed in U.S. Patent No. 5,368,995 and include zinc antimonate and indium antimonate. Other suitable conductive metal-containing particulate particles include metal borides, carbides, nitrides,
And silicides, which are disclosed in JP-A-04-055462.

Colloidal and amorphous vanadium pentoxide,
In particular, an antistatic backing layer or subbing layer containing silver-doped vanadium pentoxide is disclosed in U.S. Pat.
No. 69 and 5,439,785. Colloidal vanadium pentoxide has a width of 0.005 to 0.01.
μm, about 0.001μm in thickness, and 0.1-1μm in length
Consisting of highly twisted fine fibrils or ribbons. However, colloidal vanadium pentoxide has high p-values typical of developer solutions for wet photographic film processing.
H is soluble in H, for example, US Pat. No. 5,006,4
No. 5,221,598, 5,284,714, and 5,366,855, and must be protected by an overlying, impermeable barrier layer. Alternatively, U.S. Pat.
No. 0,706, No. 5,380,584, No. 5,427,835, No.
As taught, for example, in US Pat. No. 5,576,163, a film-forming sulfopolyester latex or polyester ionomer binder can be combined with the colloidal vanadium pentoxide in the conductive layer to minimize disintegration during processing. Polyester ionomer binders are used to improve the stability of the coating solution and enhance the adhesion of the interlayer, while providing the desired degree of process-surviving process for photographic imaging elements.
In order to ensure apabilities), a hydrophobic overcoat must be provided. The need to overcoat the antistatic layer with such a hydrophobic barrier layer adds to the manufacturing cost and complexity, the antistatic layer cannot be used as the outermost layer, and the antistatic layer A hydrophilic water-permeable layer such as a curling suppression layer or a pelloid (p
It has several potential disadvantages, including the limited possibility of direct overcoating with elloids. Therefore, it is desirable to avoid using a hydrophobic barrier layer located above the antistatic layer in a photographic element.

[0006] "Short fibers", "needle-like" or "fibrous"
Silver halide photographic film containing conductive material
Conductive backing layer and subbing layer for
Nos. 4,999,276 and 5,122,445, European Patent
Patent Application No. 404,091 and JP-A-59-06235
JP, JP-A-04-97339, JP-A-04-27937,
No. 04-29134 and No. 04-97339.
Have been. Examples of such fibrous conductive materials include anti-
Mondope SnO_TwoCoating with thin conductive layer of fine particles
Needled non-conductive metal oxide particles such as TiO_Two
Or K_TwoTi ₆O₁₃Contains. Such a needle-shaped guide
Electrical TiO_TwoConductive undercoat containing particles or
Photographic file having a backing layer and a transparent magnetic recording layer
Lum is described in U.S. Pat.No. 5,459,021.
You. Those needle-shaped conductive TiO_TwoAverage size of particles
Had a diameter of 0.2 μm and a length of 2.9 μm. It
Needle-shaped conductive TiO_TwoParticles are Ishihara Sangyo Kaisha
It is marketed under the trade name "FT-2000". However
While containing these needle-shaped particles, because they are large
The conductive layer has a decrease in conductivity, an increase in haze,
And exhibit small cracks that cause poor adhesion
I have. 0.1 to 10 g / m in dry weight^TwoNeedle-like conductive K_TwoT
i₆O₁₃Conductive subbing layer containing particles, backing
The coating layer or the surface protective layer is disclosed in JP-A-63-98656.
And No. 63-287849. Average
Needle-like conductive with a diameter of 0.05 to 1 µm and a length of 1 to 25 µm
Sex K_TwoTi₆O₁₃Particles from Otsuka Chemical Co.
ntall WK-100S ". Acicular
TiO_TwoOr K_TwoTi₆O₁₃Any of the conductive particles
Used as a conductive surface protective layer for photographic films
U.S. Pat.Nos. 5,122,445 and 5,582,959
Photographic papers in the specifications of JP-A No. 63-098656 and JP-A-63-098656.
Patented to use for conductive backing for
Application No. 616,252 and JP-A No. 01-262537
Is disclosed.

A heat-sensitive recording medium having a conductive layer containing a fibrous conductive metal oxide having a diameter of 0.3 μm and a length of 10 μm is described in JP-A-07-295146. A heat-sensitive recording medium having an antistatic layer containing acicular conductive ZnO, Si ₃ N ₄ or K ₂ Ti ₆ O ₁₃ particles is described in WO 91-05668.

[0008] The use of crystalline, single-phase, conductive metal-containing particles in transparent conductive layers for various types of imaging elements has been disclosed in US Pat.
No. 1,119 is disclosed in each specification, and is incorporated herein by reference. Suitable acicular conductive metal-containing particles may have a cross-sectional diameter of 0.02 μm or less and an aspect ratio (length: cross-sectional diameter) of 5: 1 or more. Preferred acicular conductive metal-containing particles may have an aspect ratio of 10: 1 or more. Disperse microcrystalline particles with such high aspect ratios using conventional wet milling techniques and traditional milling media without disrupting the high aspect ratio particles into lower aspect ratio debris It is well known that it is very difficult to do so. Brittle crystalline particles, such as highly acicular, conductive metal-containing particles, have a crushing strength and duration due to the need to minimize disruption of both their morphology and electrical properties. Because of the limitations, they cannot be effectively dispersed in many cases. The use of these poor dispersions in preparing conductive layers for imaging elements results in reduced conductivity as well as increased optical loss due to scattering due to particle aggregation.

Ultrafine particles of crystalline material useful in imaging elements by conventional wet milling techniques well known in the pigment and coatings industry, such as high speed mixing, ball milling or roller milling or milling using high energy media milling. Dispersions (eg, filter dyes, sensitizing dyes,
The preparation of imaging couplers, antifoggants, etc.) is disclosed in U.S. Pat. No. 4,940,654, European Patent Application 649,858 and Japanese Patent Publication No. 02-601,887. This milling method involves physically grinding the material useful for the imaging element using a milling medium generally selected from a variety of dense hard materials, for example, steel, ceramic or glass. The effect of such grinding media on the particulate material useful in the imaging element reduces the particle size and creates a dispersion. The resulting fine particle dispersion can be stabilized by using various surfactants or dispersing aids to prevent reagglomeration of those fine particles.
It is also necessary to adjust the pH during the milling process to stabilize the dispersion. The amount of grinding energy input required to produce a very small particle dispersion is also generally associated with contaminants associated with excessive grinding due to erosion of the grinding media and wear of the components of the grinding equipment. The consequences that occur. The contaminants associated with such attrition are usually present in the form of particles of a size comparable or smaller than the dissolved species or dispersed particles, Can lead to both physical and sensitometric defects in the imaging element containing the dispersed system. In addition, the heat generated during the high-intensity milling operation may initiate a chemical reaction, leading to surface defects or promoting a phase change in the dispersed material. Thus, the physical, chemical, electrical, optical, etc. properties of the dispersed particles may be substantially different from their particulate material before milling. Changes in such properties can adversely affect the performance of imaging elements containing these materials.

A wet milling method using a small milling medium containing a polymeric resin that results in a reduction in contaminants associated with milling in a dispersion of fine particles of a material useful for the imaging element is disclosed in US Pat. No. 5,478,705. No. 5,500,331, No.
Nos. 5,513,803 and 5,662,279. Preferred grinding media consist of a polymeric resin,
Nominally spherical in shape, chemically and physically inert, substantially free of metals, solvents or monomers, to avoid cracking or collapsing during the dispersion process It is sufficiently hard and tough. Or,
The grinding media may be composite particles containing core particles (having a higher density than the polymer resin) overcoated with a polymer resin. Suitable polymer milling media for preparing dispersions of materials useful in imaging elements have a particle size of 5μ.
It can range from m to 1 mm. Further, the use of comparable sized, denser ceramic or steel grinding media in addition to the polymeric grinding media is disclosed in U.S. Patent Nos. 5,500,331 and 5,513,803. For some materials, fine grinding media of ceramic or steel (<100 μm) are more effective in grinding than polymeric grinding media and produce less contaminants than conventional sized grinding media of the prior art (> 350 μm). Not found.

Compounds useful in imaging elements that can be dispersed using the polymeric grinding media claimed in US Pat. No. 5,478,705 are dye-forming couplers,
Development inhibitor releasing coupler, development inhibitor adjacent group (anchime
ric) emission couplers, masking couplers, filter dyes, thermal transfer dyes, optical brighteners, nucleating agents, development accelerators,
Contains oxidative development scavengers, ultraviolet absorbing compounds, sensitizing dyes, development inhibitors, antifoggants, bleach accelerators, magnetic particles, lubricants, and matting agents. However, U.S. Pat.
Disperse conductive metal-containing particles, especially acicular conductive metal-containing particles, that can be incorporated into transparent conductive layers useful as antistatic layers or electrodes for the various imaging elements described in 5,719,016. Utilizing a polymeric grinding media for this purpose was not disclosed or expected.

Nos. 5,719,016 and 5,73
No. 1,119, the efficiency of the conductive network formation by the acicular conductive metal-containing particles is higher and less than the film-forming binder compared to the granular, nominally spherical conductive particles. A volume fraction of conductive particles is used to allow for the preparation of a conductive layer for use in an imaging element. Increasing the aspect ratio of those conductive particles results in a further improvement in the efficiency of conductive network formation. However, milling disrupts the morphology or electrical properties of the particles or introduces contaminants associated with attrition, using conventional dispersion techniques, typically using ceramic or steel grinding media. Without this, it is very difficult to disperse crystalline particles of very high aspect ratio.

[0013]

The demands on conductive layers to be useful in imaging elements are extremely stringent and the art has shown the necessary balance of chemical, physical, optical, and electrical properties. The development of improved conductive layers has long been sought. As indicated above, the prior art for providing conductive layers useful in imaging elements is extensive,
A wide variety of suitable conductive materials have been found. However, the technology can be used in a wide variety of imaging elements, can be manufactured at a reasonable cost, is resistant to the effects of humidity changes, is durable and abrasion-resistant, It has no adverse effect on metrology or photography, exhibits adequate adhesion to the overcoat or subbing layer, exhibits suitable adhesion, and is used in solvents that the imaging element will come into contact with, such as photographic elements. There remains a significant need for improved conductive layers that are substantially insoluble in certain processing solutions.

The present invention includes needle-like conductive metal-containing particles, having improved transparency and conductivity, and not only those of imaging elements, especially silver halide-based photographic elements. It is an object of the present invention to provide a conductive layer that more effectively meets the diverse requirements of a wide variety of other types of imaging elements other than those of the prior art.

[0015]

SUMMARY OF THE INVENTION The present invention is an imaging element comprising a support, an imaging layer overlaid on the support, and a conductive layer overlaid on the support. The conductive layer contains a film-forming binder and needle-like, crystalline, single-phase conductive metal-containing particles. The acicular, crystalline, single-phase conductive metal-containing particles have a diameter of 0,0.
02 μm or less, and the aspect ratio is 3: 1 or more. The conductive layer is formed using a polymer pulverizing medium having a size of less than 350 μm and dispersing the needle-like particles to form a colloidal dispersion system. , The mixture is coated on the support, and the mixture is dried to form the conductive layer.

[0016]

DETAILED DESCRIPTION OF THE INVENTION The present invention comprises a support, at least one image forming layer, and at least one conductive layer for use in an image forming process, wherein the conductive layer is contained in a film forming binder. Containing acicular, crystalline, single-phase conductive metal-containing particles having a cross-sectional diameter of 0.02 μm or less and an aspect ratio (length: cross-sectional diameter) of 3: 1 or more dispersed in Provide the element. The dispersion of the acicular metal-containing conductive particles is achieved by a wet grinding method using a fine polymer grinding medium. By dispersing those brittle needle-like metal-containing particles using a fine polymer grinding media, the collapse of its aspect ratio is minimized and its required electrical properties are preserved. The conductive layer according to the present invention can be used as an antistatic layer to dissipate static charges. In addition to providing charge protection, such layers can also serve as transparent electrodes for use in imaging methods, such as electrostatic or dielectric imaging. As a result of one of the higher effective aspect ratios of the acicular metal-containing conductive particles dispersed using a fine polymeric grinding media, the conductive layer of the present invention provides a uniform volume percent of conductive particles with conventional particles. It generally exhibits a higher level of conductivity than a similar layer containing acicular conductive particles dispersed using a ceramic grinding media. The loading in volume percent of acicular conductive particles in the conductive layer of the present invention is about 1-70%. The lower volume percent of acicular conductive particles in the conductive layer of the present invention results in light scattering as compared to prior art conductive layers containing a higher percentage of either acicular or granular conductive particles. And reduced haze, improved adhesion of the conductive layer to the support and overcoat or subbing layer, and improved adhesion of the conductive layer. In addition, conductive layers prepared in accordance with the present invention have a significantly reduced amount of metals, ceramics, ions, and other types of contaminants resulting from grinding of the grinding media and wear of components of the grinding equipment. Is shown.

The conductive layer according to the present invention can be used for photographic, thermal copying,
Electrothermography, photothermography, dielectric recording, dye transfer
igration), laser dye ablation, thermal dye transfer, electrostatic copying, electrophotographic imaging elements and the like. For details regarding the composition and function of this wide variety of imaging elements, see U.S. Patent Nos. 5,719,016 and
5,731,119 are provided in each specification. The conductive layer of the present invention may be present as a backing layer, undercoat layer, intermediate layer or protective overcoat layer on one or both sides of the support. For silver halide imaging elements, the function of the conductive layer can be incorporated directly into the sensitized emulsion layer. In addition, its conductive properties are essentially independent of relative humidity and can be exposed to aqueous solutions having a wide range of pH values (eg, pH between 2 and 13) that are encountered in wet processing of silver halide photographic films. Even after you do. Thus, although an optional protective layer may be present on the imaging element, there is generally no need to provide a protective overcoat overlying the conductive layer of the present invention.

As described herein above,
The conductive layer of the present invention contains acicular conductive metal-containing fine particles dispersed in a film-forming polymer binder.
Dispersing these brittle acicular conductive metal-containing particles while minimizing their aspect ratio reduction and limiting their electrical property collapse, as well as avoiding contamination of the dispersion during the dispersion process That is the object of the present invention.
According to a preferred embodiment of the present invention, the dispersion of the acicular conductive metal-containing particles is achieved by a wet grinding method using a fine polymer grinding medium. These acicular conductive metal-containing particles are single phase, crystalline and have dimensions on the order of nanometers. Suitable dimensions for the acicular conductive particles are a cross-sectional diameter (short axis) of less than 0.05 μm, a length (long axis) of less than 1 μm, preferably a cross-sectional diameter of less than 0.02 μm, and a length (long axis) of Less than 0.5 μm, more preferably less than 0.01 μm in cross section diameter and less than 0.15 μm in length (long axis) These dimensions help to minimize the optical loss of the coated layer containing such particles due to Mie scattering by these particles. An average aspect ratio (major axis / minor axis) of at least 3: 1 is preferred, an average aspect ratio of 5: 1 or more is preferred, and 10:10.
An average aspect ratio of 1 or more is more preferred. It is well known that increasing the average aspect ratio of these acicular conductive particles results in an improvement in the volumetric efficiency of the conductive network formation.

One particularly useful class of acicular conductive metal-containing particles comprises acicular semiconductive metal oxide particles. The acicular semiconductive metal oxide particles suitable for use in the conductive layer of the present invention are less than 1 × 10 ⁴ Ω · cm, more preferably 1 × 10 ⁴ Ω · cm.
^It exhibits an intrinsic (volume) resistivity of less than ² Ω · cm, most preferably less than 1 × 10 ¹ Ω · cm. One such preferred acicular semiconductive metal oxide is the acicular conductive tin oxide described in U.S. Pat. No. 5,575,957, which comprises "FS-
Available under the trade name "10P" from Ishihara Techno Corporation.
It consists of single phase, crystalline tin oxide needles doped with 0.3 to 5 atomic percent antimony. The intrinsic (volume) resistivity of the acicular tin oxide, when measured as a filled powder using a DC2 probe test cell by a method similar to that described in U.S. Pat. 100Ω · cm. The average diameter of those acicular tin oxide particles, as determined by image analysis of transmission electron micrographs, is approximately 0.01 μm in cross-sectional diameter, 0.1 μm in length, and an average aspect ratio of about 10: 1. X-ray powder diffraction analysis of the acicular tin oxide confirmed that it was a single phase and highly crystalline. U.S. Patent No. 5,4
The average value of the X-ray crystallite size of these acicular tin oxide particles, determined by the technique described in US Pat. No. 84,694, is about 19 to 21 nm for the as-dried dry powder.
Other suitable acicular conductive metal oxides are, for example, tin-doped indium trioxide, aluminum-doped zinc oxide, similar to those described in U.S. Pat.No. 5,580,496, but having a smaller average cross-sectional diameter. Niobium-doped titanium dioxide, an oxygen-deficient titanium suboxide similar to the phase described in US Pat. No. 5,320,782, TiO
_x (x is less than 2) and TiO _x N _y (x + y is 2 or less). Further examples of other non-oxide acicular conductive metal-containing particles include any fine particles of metal carbides, nitrides, silicides, and borides.

The small average size of the preferred acicular conductive metal-containing particles described above minimizes the amount of light scattering, resulting in increased optical clarity and reduced haze of the conductive layer according to the present invention. In addition to maintaining transparency, the small average size of those acicular particles is such that a chain of interconnected particles forms and binds innumerably, and then, even within a thin layer of coating. Facilitate an expanded network that provides various conductive paths. Higher effective aspect ratios of the acicular metal-containing conductive particles dispersed using the fine polymer grinding media result in more efficient conductive network formation. This highly efficient conductive network formation was dispersed using a standard ceramic or steel grinding media for a certain volume percent of conductive particles relative to the polymer film forming binder in the conductive layer of the present invention. It produces a higher level of conductivity than a similar layer containing acicular conductive particles. It is a particularly important feature of the present invention that it produces a conductive layer that exhibits a relatively high level of conductivity using a relatively low volume percent of acicular conductive metal-containing particles. In addition, the resulting increase in volume percentage of the polymeric binder improves the properties associated with the various binders of the conductive layer, such as adhesion to the undercoat or overcoat layer as well as the adhesion of the conductive layer. Also, with the lower ratio of conductive particles to binder possible with the acicular conductive metal-containing particles dispersed according to the present invention, the transparency of the conductive layer is increased and surface scattering (ie, haze) is reduced. Decrease.

The acicular conductive metal-containing particles can make up about 1 to 70 volume percent of the conductive layer of the present invention. Because the density of the various suitable conductive needle-like particles varies widely, the amount of needle-like conductive metal-containing particles contained in the conductive layer is defined by volume percentage rather than weight percentage. For the preferred acicular antimony-doped tin oxide particles described herein above, this corresponds to a weight ratio of tin oxide particles to polymeric binder of approximately 1:19 to 19: 1. The optimal ratio of conductive particles to binder depends on the particle size, binder type, and the required conductivity of the particular imaging element. Using significantly less than about 1 volume percent of acicular conductive metal-containing particles will not provide a useful level of surface conductivity. Using significantly more than 70 volume percent of acicular conductive metal-containing particles undermines some of the objectives of the present invention, lowering transparency and increasing haze due to scattering losses, with the underlying conductive layer. Reduced adhesion between the layer or layers or layers above,
And the adhesion of the conductive layer is reduced. When the conductive layer of the invention is to be used as an electrode in an imaging element, to obtain a suitable level of conductivity, the acicular conductive metal oxide particles are preferably 40-70 of the layer. Should constitute volume percent. When used as an antistatic layer, it is particularly preferred to incorporate acicular conductive metal oxide particles in an amount of about 1 to 50 volume percent of the conductive layer. Use of less than 50 volume percent of acicular conductive metal oxide particles results in increased transparency, reduced haze, and improved adhesion to the undercoat and overcoat layers and improved adhesion of the conductive layer. In addition, the use of lower volume percentages of metal oxide particles results in reduced tool wear and reduced fouling during finishing operations. Thus, the antistatic layer of the present invention comprises 70% by volume or less, preferably 50% by volume or less, more preferably 25% by volume or less, and most preferably 10% by volume or less of the acicular conductive metal-containing particles. Contains.

Polymeric film-forming binders useful in conductive layers prepared by the method of the present invention include water-soluble, hydrophilic polymers such as gelatin, gelatin derivatives, maleic anhydride copolymers, cellulose derivatives such as carboxymethylcellulose, hydroxyethylcellulose. ,
Cellulose acetate butyrate, diacetylcellulose or triacetylcellulose, 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, derivatives of the above polymers, and other synthetic resins. Other suitable binders are ethylenically unsaturated monomers such as acrylates containing acrylic acid, methacrylates containing methacrylic acid, acrylamide and methacrylamide, itaconic acid and its half esters and diesters, styrene containing substituted styrene, acrylonitrile and It includes aqueous emulsions of addition polymers and interpolymers prepared from methacrylonitrile, vinyl acetate, vinyl ethers, vinyl and vinylidene halides, and olefins, and aqueous dispersions of polyurethane or polyester ionomers. Aqueous emulsions of gelatin and gelatin derivatives, polyurethanes, polyester ionomers, and vinylidene halide interpolymers are preferred binders.

Solvents useful for preparing dispersions and coatings of conductive acicular metal-containing particles according to the method of the present invention include:
Water, alcohols such as methanol, ethanol, propanol, isopropanol, ketones such as acetone, methyl ethyl ketone and methyl isobutyl ketone, esters such as methyl acetate and ethyl acetate,
Glycol ethers, such as methyl cellosolve, ethyl cellosolve, ethylene glycol, and mixtures thereof. Preferred solvents include water, alcohol, and acetone.

In addition to binders and solvents, other components well known in the photographic art may be included in the conductive layers of the present invention. Other additives such as matting agents, surfactants or coating aids, polymeric lattices for improving dimensional stability, thickeners or viscosity modifiers, hardeners or crosslinkers, soluble antistatics, Soluble and / or solid particle dyes, antifoggants, leveling agents, and various other conventional additives may optionally be present in any or all of the multilayer imaging elements.

The dispersion of acicular conductive metal-containing particles in a suitable liquid vehicle can be prepared in any suitable amount by any of a variety of wet milling methods well known in the pigment dispersion and coatings arts, including suitable amounts of dispersants, colloids. It can be prepared in the presence of a stabilizer or a polymeric binder. Liquid vehicles useful for preparing the dispersion of needle-like metal-containing particles of the present invention include water, aqueous solutions of salts, alcohols such as methanol, ethanol, propanol, butanol, ethylene glycol, and as described herein above. Contains other solvents. The dispersing aid can be selected from a wide variety of surfactants and surface modifiers, such as those described in US Pat. No. 5,145,684. The dispersing aid can be present in an amount ranging from 0.1 to 20% of the dry weight of the acicular conductive particles.

In general, the grinding media may be particles, preferably approximately spherical in shape, such as polymeric resin beads. Polymeric resins suitable for use as polymeric grinding media are chemically and physically inert, substantially free of metals, solvents, and monomers, which break or crack during the dispersion process, or It has sufficient hardness and toughness to avoid crushing.
Suitable polymeric resins are cross-linked polystyrene, such as polystyrene cross-linked with divinylbenzene, styrene copolymers, polycarbonates, polyacetals, such as Delr
in ^TM , vinyl chloride polymers and copolymers, polyurethanes, polyaramids, polytetrafluoroethylenes such as Teflon ^™ , and other fluoropolymers, high density polyethylene, polypropylene, cellulose ethers and esters such as cellulose acetate, polyacrylates such as polymethacrylic acid Methyl, polyhydroxy methacrylate, and polyhydroxyethyl acrylate, including silicone-containing polymers such as polysiloxanes. The polymers include polylactide, polyglycolide, copolymers of lactide and glycolide, polyanhydrides, poly (hydroxyethyl methacrylate), polyiminocarbonate, poly (N-acylhydroxyproline) ester, poly (N-palmitoylhydroproline ) It may be biodegradable, including esters, ethylene-vinyl acetate copolymers, polyorthoesters, polycaprolactone, and polyphosphazenes. Preferred polymers for the polymeric grinding media according to the present invention are polystyrene, polymethyl methacrylate, and polycarbonate cross-linked with divinylbenzene.

The polymeric medium may have a density ranging from 0.8 to about 3 g / cm ³ . For the dispersion of acicular conductive particles of the present invention, a low density is preferred in order to minimize grinding and collapse of the aspect ratio of the particles.
Higher density grinding media provides more effective grinding and dispersion. Further grinding is particularly disadvantageous for acicular conductive metal-containing particles useful in the present invention.

Alternatively, the polymeric grinding media may be particles having a core and a polymeric resin coating thereon as described in US Pat. No. 5,478,705. The core material may be selected from materials known to be useful for the grinding media. Suitable core materials include zirconium oxide, zirconium silicate and related phases stabilized with either magnesia or yttria, glass, stainless steel, titania, alumina, beria, and other ceramic materials. I have. However, the use of a core material having a density greater than about 2.5 g / cm ³ may result in a grinding media that causes the aspect ratio grinding and collapse of the acicular conductive particles. The core materials can be coated with various polymeric resins, such as those described herein above, by methods well known in the art, such as spray coating, fluidized bed coating, and melt coating. The adhesion of the polymer resin to the core particles can be improved by providing an optional adhesion promoting layer or tie layer and roughening the surface of the core layer or by corona discharge treatment or the like. The thickness of the polymeric coating is preferably less than the diameter of the core particle.

A preferred polymeric grinding media for use in accordance with the present invention is a poly (styrene-copolymer) prepared as described in US Pat. No. 5,478,705 and European Patent Application 649,858. −divinylbenzene) −
20/80 beads. Polymeric grinding media suitable for the present invention may range in size up to about 350 μm or less. However, to ensure a high quality dispersion and to minimize grinding and disintegration of the aspect ratio of the acicular conductive particles, media having an average particle size of less than about 250 μm are preferred, and those having an average particle size of less than about 100 μm are preferred. More preferably, about 50 μm
Less than is most preferred. The use of grinding media having a particle size of less than about 5 μm is also contemplated.

The above wet grinding method can be carried out using a suitable type of high-speed disperser or medium grinding device. High-speed dispersers are simple containers with high-speed mixing blades, such as Cowles-type sawtooth impellers, rotors,
It may consist of a stator mixer or other conventional mixer capable of producing high fluid velocity and high shear. The media milling equipment includes conventional mill designs such as roller mills, ball mills, stirred ball mills, attritors, horizontal media mills, vertical media mills, sand mills, pebble mills, vibratory mills, planetary mills, shaker mills, and bead mills. May be. The processing time depends on the individual wet milling method and the equipment selected, the surface characteristics of the individual particles to be dispersed, the average size of the agglomerated particles, the milling medium (s), the type and amount of dispersing aid, As well as other processing conditions, which can range from about 1 hour to over 100 hours. For ball mills, processing times of days to weeks may be required. High energy media mills can produce equivalent or better quality dispersions with substantially shorter residence times. However, in order to prepare a dispersion of acicular conductive metal-containing particles using the polymer pulverizing medium according to the present invention, a high-speed dispersing machine is used because of its simplicity of design, low cost, and ease of use. It is preferred to use a simple container with Preferred container shapes include those having a diameter to depth ratio of about 1: 1 to 1:10. Container volumes can range from less than 1 mL to more than 4000 liters. Container covers can be used to minimize contamination during processing and maintain a pressure, reduced pressure or inert atmosphere. A jacketed container capable of controlling the temperature during processing is preferred. Processing temperatures can range between the freezing and boiling temperatures of the liquid vehicle. By applying high pressure, boiling at high temperatures can be suppressed. Suitable impeller designs include axial or radial flow impellers, nails, disks, saw disperser impellers, and the like. High speed mixers using radial flow are preferred because they produce both high media velocity and high shear with minimal pumping action. While a mixer speed of 1 to 50 m / s can be used, a speed of 20 to 40 m / s is preferred for simple vessels. The preferred ratio of grinding media, acicular conductive particles, liquid vehicle, and optional dispersing aids and colloid stabilizing agents can vary within wide limits, and the individual acicular particles selected, their polymer milling It depends on the size and specific gravity of the media, the type of high-speed disperser or mill chosen, and other parameters associated with the process.

A colloidal dispersion of conductive metal-containing needle-like particles in a suitable liquid vehicle is formulated with a polymeric film-forming binder and various additives and applied to various supports to provide the present invention. A conductive layer can be formed. Typical photographic film supports include cellulose nitrate, cellulose acetate, cellulose acetate butyrate, cellulose acetate propionate, polyvinyl acetal, polycarbonate, polystyrene, polyethylene terephthalate, polyethylene naphthalate, isophthalate used in the manufacture of the film support. Polyethylene terephthalate or polyethylene naphthalate in which the acid, 1,4-cyclohexanedicarboxylic acid or 4,4-biphenyldicarboxylic acid moiety is contained therein, such as cyclohexanedimethanol, 1,4-butanediol, diethylene glycol, polyethylene glycol Polyesters in which other glycols have been used, such as the ionomers described in U.S. Pat. No. 5,138,024, which is incorporated herein by reference; 5-sodiosulfo-
Includes blends or laminates of the above polymers, such as polyester ionomers, polycarbonates made using 1,3-isophthalic acid or similar ion-containing monomers. The support may be transparent or opaque depending on the application. The transparent film support may be colorless or colored by the addition of a dye or pigment. The film support may be a corona discharge, glow discharge, UV exposure, flame treatment, electron beam treatment, or dichloroacetic acid and trichloroacetic acid, as described in U.S. Pat.No. 5,718,995.
Phenol derivatives such as resorcinol, 4-chloro-
Surface treatment can be performed by various methods including treatment with an adhesion promoter including 3-methylphenol and p-chloro-m-cresol, and solvent washing, or a copolymer containing vinylidene chloride, a butadiene-based copolymer,
Overcoat with an adhesion promoting primer or tie layer containing polymers such as glycidyl acrylate or methacrylate containing copolymers, maleic anhydride containing copolymers, polyesters, polyamides, polyurethanes, condensation polymers such as polycarbonates, mixtures and blends thereof. can do. Other suitable opaque or reflective supports are paper, polymer-coated paper, such as polyethylene, polypropylene, and paper coated or laminated with ethylene-butylene copolymer, synthetic paper, pigmented polyester, and the like. is there. Among these supports, cellulose triacetate, polyethylene terephthalate, and 2,6-
Polyethylene naphthalate prepared from naphthalenedicarboxylic acid or a derivative thereof is preferred. The thickness of the support is not critical. A support thickness of 50 to 254 .mu.m (2 to 10 mils) is suitable for photographic elements according to the present invention.

Using any of a variety of well-known coating methods, a dispersion containing acicular conductive metal-containing particles, a polymeric film-forming binder, and various additives in a liquid vehicle can be prepared as described above. To a film or paper support. The hand-painting technique is
Including using an application rod or knife or doctor blade. Mechanical application methods include air doctor coating, reverse roll coating, gravure coating, curtain coating, bead coating, slide hopper coating, extrusion coating, spin coating, and the like, as well as other coating methods known in the art.

The conductive layers of the present invention can be applied to the above supports at any suitable coverage, depending on the specific requirements of the particular type of imaging element. For example, for silver halide photographic films, the preferred dry coverage of acicular antimony-doped tin oxide in the conductive layer is preferably in the range of about 0.01 to ² g / m2. The most preferred dry coverage is in the range of about 0.03~1 g / m ^2. The conductive layer of the present invention generally has a surface resistivity (less than 1 × 10 ¹² Ω / □, preferably less than 1 × 10 ¹⁰ Ω / □, more preferably less than 1 × 10 ⁸ Ω / □ (20% RH, 20 ° C.). ).

The conductive layers of the present invention can be incorporated into multilayer imaging elements in any of a variety of configurations, depending on the needs of the particular imaging element. For example, in a photographic element, the conductive layer can be applied to a film support as a subbing layer on one or both sides of the support. When applying the conductive layer containing the acicular metal-containing particles as a subbing layer under the sensitized emulsion layer,
There may optionally be an intermediate layer between it and the sensitized emulsion layer, for example a barrier layer or an adhesion-promoting layer, but there is no need to apply them. In the case of photographic elements for direct or indirect X-ray applications, the conductive layer can be applied to one or both sides of the film support. In some such photographic elements, a conductive subbing layer is applied to only one side of the support, and the sensitized emulsion is coated on both sides of the support. In another type of photographic element, one side of the support is coated with a sensitized emulsion layer, and the other side of the support is coated with a gelatin-containing pelloid layer, Under the sensitized emulsion layer or under the pelloid as part of a multi-component curl control layer,
Alternatively, the conductive layer can be applied to both sides of the support. Moreover, further optional layers may be present. In yet another type of photographic element, a conductive subbing layer can be applied either below or above a gelatin subbing layer containing an antihalation dye or pigment. Alternatively, both the antihalation function and the antistatic function can be combined in a single layer containing the acicular conductive particles, the antihalation dye, and the binder. This hybrid layer is generally coated on the same side of the support as the sensitized emulsion layer. The conductive layer of the present invention can also be used as an outermost layer of an imaging element, for example, as a protective layer overlying the imaging layer. When the conductive layer is applied over the sensitized emulsion layer, an intermediate layer, such as a barrier layer or an adhesion promoting layer, is optionally present between the conductive overcoat layer and the imaging layer. Although good, there is no need to apply them. Alternatively, the conductive layer of the present invention can function as a friction-resistant backing layer applied to the support on the opposite side of the imaging layer. Further, the conductive layer of the present invention can be applied as the outermost layer on both sides of the support. Other additives, such as polymeric lattices to improve dimensional stability, hardeners or crosslinkers, surfactants, and other well-known additives are present in any or all of the layers described above. You may.

In a particularly preferred embodiment, the imaging element comprising the conductive layer of the present invention is a photographic element whose structure and composition can vary widely. For example, the photographic elements can vary widely with respect to the type of support, the number and composition of their imaging layers, and the number and type of auxiliary layers included in those elements.
In particular, photographic elements include steel photographic films, cinema films, X-ray films, graphic arts films,
It may be paper prints and microfish. Research Disclosure (Res
The use of the conductive layer of the present invention in small films described in item 36230 ( earch disclosure) (June 1994) is also explicitly contemplated. Photo elements are
It can be either a simple black-and-white or monochrome element or a multilayer and / or multicolor element adapted for use in a negative-positive or reversal process. Suitable photosensitive imaging layers are those that provide a color or black and white image. Such a photosensitive layer may be an image forming layer containing silver halide, for example, silver chloride, silver bromide, silver bromoiodide, silver chlorobromide and the like. Negative and reversal silver halide elements are contemplated. For reversal films, the emulsion layers described in U.S. Pat. No. 5,236,817, especially Examples 16 and 21, are particularly preferred. Known silver halide emulsion layer, for example Risachide
Disclosure, Volume 176, Item 17643 (December 1978
Mon), Research Disclosure , Volume 225, Item 225
34 (January 1983), Research Disclosure , Item
36544 (September 1994) and Research Disclosure
Catcher over, none of those described in the references cited in item 37038 (February 1995), as well as herein,
Useful in preparing photographic elements according to the present invention. Generally, the photographic elements are prepared by coating one side of the film support with one or more layers comprising a silver halide emulsion and optionally one or more subbing layers. The coating method can be performed in a continuously running coater that applies a single layer or multiple layers to the support. For multicolor elements, the layers can be coated simultaneously on a composite film support, as described in US Pat. Nos. 2,761,791 and 3,508,947. Additional useful coating procedure and drying procedure policer
Chi Disclosure , Volume 176, Item 17643 (December 1978
Month).

Imaging elements incorporating the conductive layers of this invention include adhesion promoting layers, lubricant or transport control layers, hydrophobic barrier layers, antihalation layers, antifriction and antiscratch layers, and other special functional layers. Further layers can be included. Certain imaging applications, such as color negative films, color reversal films, black and white films, color and black and white photographic paper, electrographic media,
Imaging elements incorporating conductive layers according to the present invention useful for dielectric recording media, heat treatable imaging elements, thermal dye transfer recording media, laser ablation media, ink jet media, and other imaging applications include photographic technology and It should be readily apparent to those skilled in other imaging techniques.

[0037]

The method of the present invention is illustrated by the following detailed examples. However, the scope of the present invention is never limited to these examples.

Preparation of a dispersion of acicular conductive particles Prepare a dispersion of acicular antimony-doped tin oxide used to formulate a coating solution applied to a support for the examples described below. To do this, we used a consistent approach. The method includes the following general steps.

(A) A slurry of the acicular conductive particles, the vehicle, the dispersant, and the polymer pulverizing medium is formed. (B) mixing the grinding media and the slurry of acicular conductive particles at high speed in a mixing vessel or mixing chamber using a suitable disperser impeller. (C) Separating the dispersion of acicular conductive particles from the polymer pulverization medium by filtration.

Dispersion Sample A 50 g of FS-10P (Ishihara Techno Cor
p.) and 500 g of deionized water, and adjusting the pH to above 8 using a 1% NaOH solution to obtain a needle-like conductive tin oxide powder having a solid content of about 20% by weight. An aqueous slurry containing was prepared. The premixed slurry is mixed with a poly (styrene-co-divinylbenzene) -20/80 grinding media having an average diameter of 50 μm, about 275 g (300 cm ³ ).
Together with. The combined mixture of slurry and grinding media is
Disp with es type sawtooth impeller (40mm diameter)
The ermat lab scale high speed mixer was used for 96 hours in a cylindrical 1 liter water cooled jacketed tank using an impeller shaft speed of 2000 rpm. A processing temperature of nominally 20 ° C. was maintained throughout the processing. After a processing time of 96 hours, a vacuum filtration system such as US Pat.
The dispersion of acicular tin oxide particles was separated from the grinding media using that described in 62,279. The dispersion contained about 10% solids by weight. A small sample of the dispersion was evaporated to dryness. The filled powder resistivity of the obtained powder was measured by a method similar to that described in US Pat. No. 5,236,737, and the results are shown in Table 1. The average X-ray crystal size of the acicular particles recovered from the dispersion was measured by the method described in US Pat. No. 5,484,694 and the values are shown in Table 1. The average crystal size of FS-10P powder before dispersion is
It was measured to be 19.5 nm. Trace metals in the powder are analyzed by inductively coupled plasma atomic spectroscopy (ICP-AES),
Table 2 shows the results.

Dispersion Sample B An aqueous slurry containing about 20% by weight solids FS-10P acicular tin oxide powder was prepared as described above for Dispersion Sample A. This premixed slurry was mixed with poly (styrene-co-divinylbenzene) having an average diameter of 50 μm.
Treated as for Dispersion Sample A, but for only 72 hours, with 20/80 grinding media, about 275 g (300 cm ³ ). After a treatment time of 24 and 48 hours for the measurement, a small aliquot of the mixture of the medium and the dispersion was taken. After 72 hours of treatment, the majority of the dispersion of acicular tin oxide particles was separated from the grinding media using the vacuum filtration system described for Dispersion Sample A. The dispersion contained about 14% solids by weight. A small sample of the dispersion was evaporated to dryness. The filled powder resistivity and average X-ray crystal size of the acicular tin oxide particles recovered from these dispersions were measured, and the values are shown in Table 1. Trace metals in the powder were analyzed by inductively coupled plasma atomic spectroscopy (ICP-AES) and the results are shown in Table 2.

Dispersion Sample C An aqueous slurry containing about 20% by weight solids FS-10P acicular tin oxide powder was prepared using Dequest 2006 (Monsanto Chemica).
l Co.) prepared as described above for Dispersion Sample A except that 2.2 g of a 45% aqueous solution (1% based on the dry weight of FS-10P) of a 45% aqueous solution was added to the slurry as a dispersing aid. did. This premixed slurry was combined with about 275 g (300 cm ³ ) of poly (styrene-co-divinylbenzene) -20/80 grinding media having an average diameter of 50 μm and processed as in Dispersion Sample B. After a treatment time of 24 and 48 hours for the measurement, a small aliquot of the mixture of the medium and the dispersion was taken. After 72 hours of treatment, the majority of the dispersion of acicular tin oxide particles was separated from the grinding media using the vacuum filtration system described for Dispersion Sample A. This dispersion contained about 16% solids by weight. A small sample of the dispersion was evaporated to dryness. The filled powder resistivity and average X-ray crystal size of the acicular tin oxide particles recovered from these dispersions were measured, and the values are shown in Table 1.

Dispersion Sample D 4.4 g of a 45% aqueous solution of Dequest 2006 containing an aqueous slurry containing about 20% by weight solids of FS-10P acicular tin oxide powder.
(2% based on the dry weight of FS-10P) was prepared as described above for Dispersion Sample A, except that it was added to the slurry as a dispersing aid. The premixed slurry is mixed with a poly (styrene-co-divinylbenzene) -20/80 grinding media having an average diameter of 50 μm, about 275 g (300 cm ³ ).
And treated for 48 hours as for dispersion sample A. After 48 hours of treatment, the dispersion of acicular tin oxide particles was separated from the grinding media using the vacuum filtration system described for Dispersion Sample A. The dispersion contained about 19% solids by weight. A small sample of the dispersion was evaporated to dryness. The filling powder resistivity and average X-ray crystal size of the acicular tin oxide particles recovered from this dispersion were measured, and the values are shown in Table 1.

Dispersion Sample E Needle-like FS using conventional high energy small medium grinding technology
A dispersion of -10P was prepared. FS-10P of about 20% by weight in solid content
An aqueous slurry containing acicular tin oxide powder was prepared as described above. In the premixed slurry, 45 of Dequest 2006
4.4 g of a 2% aqueous solution (2% based on the dry weight of FS-10P) was added as a dispersing aid. This pre-mixed slurry was prepared on a laboratory scale 0.3 liter Dyno Mill (A., Basel, Switzerland).
Standard zirconium silicate grinding media with an average diameter of about 500 μm (Quartz Produc, Plainfield, NJ) in a grinding chamber of Bachofen AG Maschininenfabrik)
SEPR medium obtained from tsCorp.) about 605 g (255 cm ³ )
And treated for a total residence time of 1 hour. In order to hold the grinding media in the grinding chamber, the clearance of the media separator in the media mill was adjusted to 100 μm. 1
After a period of residence time, a dispersion of acicular tin oxide particles was discharged from the mill. This dispersion contained about 21% by weight of solids. A small sample of the dispersion was evaporated to dryness. The filled powder resistivity and the average X-ray crystal size of the needle-like particles recovered from this dispersion were measured, and the values are shown in Table 1. X-ray fluorescence analysis of the powder revealed that zirconium was present as the main contaminant. Further, trace metals in the powder were analyzed by inductively coupled plasma atomic spectroscopy (ICP-AES), and the results are shown in Table 2.

Dispersion Sample F An aqueous slurry containing about 20% by weight solids of FS-10P needle-like tin oxide powder was mixed with 4.4 g of a 45% aqueous solution of Dequest 2006.
(2% based on the dry weight of FS-10P) was prepared as described above for Dispersion Sample A, except that it was added to the slurry as a dispersing aid. This premixed slurry was combined with about 700 g (300 cm ³ ) of zirconium silicate grinding media having an average diameter of 50 μm and treated as for Dispersion Sample A, but only for 24 hours. After a treatment time of 24 hours, the dispersion of acicular tin oxide particles was separated from the grinding media using the vacuum filtration system described for dispersion sample A. The dispersion contained about 25% solids by weight. A small sample of the dispersion was evaporated to dryness. The filled powder resistivity and the average X-ray crystal size of the needle-like particles recovered from this dispersion were measured, and the values are shown in Table 1. X-ray fluorescence analysis of the powder revealed that zirconium was present as the main contaminant. Trace metals in the powder were analyzed by inductively coupled plasma atomic spectroscopy (ICP-AES) and the results are shown in Table 2.

Dispersion Sample G A commercially available dispersion of acicular conductive tin oxide particles available from Ishihara Techno Corporation under the trade name "FS-10D" was evaluated. The dispersion contained nominally 21% solids by weight. A small sample of the dispersion was evaporated to dryness. The filled powder resistivity and average X-ray crystal size of the needle-like particles recovered from the dispersion were measured, and the values are shown in Table 1. X-ray fluorescence analysis of the powder revealed that zirconium was present as a contaminant. Trace metals in the powder were analyzed by inductively coupled plasma atomic spectroscopy (ICP-AES) and the results are shown in Table 2.

Dispersion Sample H Another sample of the commercially available "FS-10D" that was different from Dispersion Sample G was evaluated. The dispersion contained nominally 20% solids by weight. A small sample of the dispersion was evaporated to dryness. The filled powder resistivity and average X-ray crystal size of the needle-like particles recovered from the dispersion were measured, and the values are shown in Table 1. X-ray fluorescence analysis of the powder revealed that zirconium was present as the main contaminant. Trace metals in the powder were analyzed by inductively coupled plasma atomic spectroscopy (ICP-AES) and the results are shown in Table 2.

[0048]

[Table 1]

[0049]

[Table 2]

The minimum value of the increase in filled powder resistivity observed when compared to the measured value for FS-10P powder before treatment (ie, 90 Ω · cm) and the decrease for samples B and C treated for 72 hours. Based on the above, the collapse of the conductivity of the acicular conductive tin oxide particles is reduced by using a polymer grinding medium. These filled powder resistivity values are 50 μm Zr
SiO ₄ medium is much smaller than the value obtained for the standard ZrSiO ₄ or any of the samples were milled one hour using a medium in watching or medium is treated for 24 hours using. Furthermore, these values are much lower than those for any of the commercially available dispersion samples. A similar trend was revealed by comparison of the X-ray crystal size for the FS-10P sample dispersed using the polymer milling media with that for the sample milled using the ceramic media. The crystal size was smaller for samples milled using ceramic media and for commercially available dispersion samples. This reduction in crystal size is consistent with the collapse of grain morphology that results in a reduction in aspect ratio. In addition, contaminants resulting from erosion of the ceramic grinding media, such as Zr, Si, and Al
And the amounts of Fe, Cr, Ni, and Mn resulting from wear of the stainless steel parts of the milling equipment use ceramic media rather than for dispersions prepared according to the present invention using polymeric media. There is much more for the dispersions prepared and commercially available dispersions. A similar reduction in the amount of contaminants for dispersions of other materials useful in imaging elements prepared using a polymeric medium is disclosed in U.S. Pat.
No. 78,705.

Example 1 (a, b) Antistatic layer coating formulation having acicular antimony-doped tin oxide particles dispersed in water with dispersed polyurethane binder, dispersing aid, coating aid, crosslinker, and optional additives. Was prepared using Dispersion Sample A. The weight ratio of acicular tin oxide to polyurethane binder was nominally 1: 4. The coating formulation is shown below.

Component weight% (wet) ポ リ ウ レ タ ン polyurethane dispersion (Witcobond W -236, Witco Chemical Co.), 20% 12.68% Wetting aid (Triton X-100: Rohm & Haas), 1% 3.30% Dispersion sample A, 9.8% 6.47% Water 77.55%

The above coating formulation had a nominal total dry coverage of 1075 and 1075 for Examples 1a and 1b, respectively.
So that 645 mg / m ^2, about moving 101.6μm (4
(Mil) of polyethylene terephthalate support using a coating hopper. The support was pre-coated with a typical subbing layer containing a vinylidene chloride-based terpolymer latex.

The electrical performance and optical clarity of the antistatic layer described herein were evaluated. U.S. Patent No.
The surface electrical resistivity (SER) of the conductive layer was measured at a nominal 20 ° C. and 50% relative humidity using a two-point DC probe by a method similar to that described in US Pat. No. 2,801,191. . Total optical density (ortho) and ultraviolet density (Dmin) were evaluated at 530 nm and 380 nm, respectively, using an X-Rite Model 361T transmission densitometer. By correcting the total optical density and ultraviolet density for the contribution from the support, the UVDmin
And the net or difference values of ortho Dmin were calculated. Table 3 shows the properties of the antistatic layers, their surface resistivity values, and the net ultraviolet and optical densities.

Examples 2-4 (a, b) Antistatic layer coating formulations were prepared in the same manner as in Example 1 except that Dispersion Samples B-D were used instead of Dispersion Sample A. An antistatic layer was applied to the support to give a nominal total dry coverage of 1075 mg / m ² for samples 2a, 3a and 4a and 645 mg / m ² for samples 2b, 3b and 4b. Table 3 shows the surface resistivity values and the net ultraviolet and optical densities. These examples demonstrate that excellent antistatic properties can be achieved for a variety of dispersion conditions. S for example 4
Comparison of the ER value with that for Examples 1-3 indicates that optimization of dispersion conditions (eg, total energy input, processing time, choice of dispersant, dispersant concentration, etc.) using the polymeric medium according to the present invention It has been demonstrated that a considerable improvement in the quality of the dispersion and consequently in the properties of the conductive layer can be achieved.

Comparative Examples 1-4 Antistatic layers were prepared in the same manner as in Examples 1-4, except that the acicular tin oxide dispersion was not prepared by the method of the present invention. Comparative Examples 1 and 2 are examples of dispersion A
Containing the same acicular tin oxide powder (FS-10P) as -D, but conventional (over 350 μm) zirconium silicate grinding media or zirconium silicate micro media (50 μm)
Was used to utilize dispersion samples E and F, respectively, dispersed according to prior art methods. Comparative Example 3
And 4 from Ishihara Techno Corporation "FS-10
Dispersion samples G and H, which are commercially available dispersions of acicular antimony-doped tin oxide available under the trade name "D", were utilized. Surface resistivity values and net ultraviolet and optical densities are shown in Table 3. Based on the data shown in Table 3,
Antistatic layers containing acicular tin oxide and a polyurethane binder dispersed according to the present invention clearly exhibit significantly lower surface resistivity values compared to those for the prior art dispersion methods. However, there is a relatively small effect on its optical clarity. Comparative Example 1 reveals that a dispersion of acicular tin oxide by conventional small media grinding using a ceramic grinding media yields an essentially non-conductive layer even after only one hour of grinding. Proven. Comparative Example 2 further illustrates the use of the method of the present invention using ceramic (ZrSiO ₄ ) grinding media of similar size to the polymeric media used to prepare dispersion samples A, B, C, and D. It has been demonstrated that even processing times which are significantly shorter than those useful in Example 1 cause significant degradation of the electrical performance of the antistatic layer. With a dispersion treatment time of greater than 48 hours, the present invention provides an antistatic layer having a much lower surface resistivity value than such an antistatic layer prepared using a commercially available "FS-10D" dispersion. provide.
In the case of dispersion sample D with a dispersion treatment time of 48 hours, the antistatic layers of the present invention (eg, Examples 4a and 4b) are comparable to Comparative Examples 3 (a and b) and 4 (a and b). It provided antistatic performance and optical performance. In addition, the dispersion method of the present invention, as shown in Table 2, results in significantly lower amounts of contaminants, and the antistatic layers containing these dispersions can be used when used in photographic elements. Minimize any potential adverse effects on sensitometry.

Examples 5-8 and Comparative Examples 5-8 Antistatic coating formulations having a weight ratio of acicular tin oxide to polyurethane binder of 1: 3 were prepared in a manner similar to the Examples and Comparative Examples above. 1075 and 645
As a nominal total dry coverage of mg / m ^2, and apply the antistatic layer coating formulation to a support. Examples 5-8 utilized dispersion samples AD prepared according to the method of the present invention, and Comparative Examples 5-8 utilized dispersion samples EH prepared according to the prior art. As shown in Table 3,
The dispersion method of the present invention provided excellent antistatic performance even with dispersion treatment times longer than 48 hours.

Example 9 (ac) Antistatic coating having acicular antimony-doped tin oxide particles dispersed in water with gelatin, dispersing aids, coating aids, hardeners, crosslinkers, and optional additives. The formulation was prepared using Dispersion Sample A. 1075, 6
As a nominal total dry coverage of 45 and 430 mg / m ^2,
The antistatic layer coating formulation was applied to a support. 30:70 nominal weight ratio of acicular tin oxide to gelatin
And The coating formulation is shown below.

Component weight% (wet) ゼ ラ チ ン gelatin, 5% 42.70% Wetting aid (Triton X-100: Rohm & Haas), 1% 3.30% Dispersion sample A, 9.8% 9.34% 2,3-dihydroxy-1,4-dioxane, 1% (as hardener) 7.47% water 37.19%

Examples 10-11 and Comparative Examples 9-12 Using Dispersion Samples B and C for Examples 10 and 11, and Dispersion Samples EH for Comparative Examples 9-12, respectively, An antistatic coating formulation was prepared in a similar manner. Table 4 shows the surface resistivity values and the net ultraviolet and optical densities. In addition, these examples demonstrate that the method of the present invention shows that, in addition to the superior performance demonstrated by the antistatic layer of Examples 1-8 containing a hydrophobic film forming binder, the acicular tin oxide particles are hydrophilic. It has been demonstrated that it also improves the performance of the antistatic layer dispersed in the colloid binder.

Examples 12-14 and Comparative Examples 13-16 Charged in the same manner as in Examples 9-11 and Comparative Examples 9-12, except that the weight ratio of acicular tin oxide to gelatin was nominally 35:65. An inhibitor coating formulation was prepared. Ten
75, 645 and so that the nominal total dry coverage of 430 mg / m ^2, and apply the coating formulation to a support. Table 4 shows the values of the surface resistivity value, the net ultraviolet density, and the net optical density. Examples 12c and 14c show surface resistivity values comparable to those of Comparative Examples 15a and 16a, where the acicular tin oxide dry coverage contains an acicular tin oxide dispersion prepared using the prior art method. It has been demonstrated that a comparable level of electrical performance can be achieved with a conductive layer prepared according to the present invention, which is approximately one-half that of the conductive layer in question.

[0062]

[Table 3]

[0063]

[Table 4]

Other preferred embodiments of the present invention are described below in connection with the claims.

[1] An image-forming element comprising a support, an image-forming layer overlaid on the support, and a conductive layer overlaid on the support, wherein the conductive layer is formed of a film. Comprising a binder and needle-like, crystalline, single-phase conductive metal-containing particles, wherein said particles have a diameter of 0.02 μm or less and an aspect of 3: 1 or more, and wherein said conductive layer is less than 350 μm. Using a polymer pulverizing medium having an average particle size of, the needle-like particles are dispersed to form a colloidal dispersion system, and the colloidal dispersion system and the film-forming binder are combined to form a mixture. Formed on the support, and drying the mixture to form the conductive layer.
Imaging element.

[2] The imaging element of [1], wherein the acicular, crystalline, single-phase conductive metal-containing particles comprise 1 to 70 volume percent of the conductive layer.

[3] The imaging element of [1], wherein the acicular, crystalline, single-phase, conductive metal-containing particles comprise 1 to 50 volume percent of the conductive layer.

[4] The imaging element of [1], wherein said particles comprise a dry weight coverage of 5 to 1000 mg / m ² .

[5] The imaging element according to [1], wherein the conductive layer has a surface resistivity of 1 × 10 ¹⁰ Ω / □.

[6] The image formation according to [1], wherein the needle-shaped, crystalline, single-phase conductive metal-containing particles constitute a filled powder resistivity of 10 ³ Ω · cm or less. element.

[7] The needle-like, crystalline, single-phase conductive metal-containing particles include needle-like doped tin oxide particles, needle-like antimony-doped tin oxide particles, needle-like niobium-doped titanium dioxide particles, and needle-like particles. An imaging element according to [1], comprising metal nitride, needle metal carbide, needle metal silicide, needle metal boride or needle tin doped indium trioxide.

[8] The fine polymer pulverizing medium is a crosslinked polystyrene, styrene copolymer, polycarbonate,
Comprising vinyl acetate, vinyl chloride polymer, polyurethane, polyaramid, high density polyethylene, polypropylene, polyacrylate or fluoropolymer,
The image forming element according to [1].

[9] The image-forming element according to [1], wherein the average particle size of the fine polymer pulverization medium is 50 μm or less.

[10] The film-forming binder of the conductive layer comprises a water-soluble polymer, gelatin, a cellulose derivative, a water-insoluble polymer, a water-dispersible polyester ionomer, a vinylidene chloride-based terpolymer or a water-dispersible polyurethane. The image forming element according to [1].

[11] The support comprises a polyethylene terephthalate film, a cellulose acetate film or a polyethylene naphthalate film, [1].
An imaging element according to claim 1.

[12] (1) A support, (2) a conductive layer serving as an antistatic layer located on the support, and (3) a silver halide emulsion layer located on the conductive layer. A photographic film comprising the conductive layer,
Comprising a film-forming binder and acicular, crystalline, single-phase conductive metal-containing particles, wherein the particles comprise 0.02
having a diameter of less than μm and an aspect of greater than 3: 1;
The conductive layer forms a colloidal dispersion by dispersing the needle-like particles using a polymer pulverizing medium having an average particle size of less than 350 μm, and the colloidal dispersion and the film-forming binder are combined. A photographic film formed by forming a mixture, coating the mixture on the support, and drying the mixture to form the conductive layer.

[13] Including (1) a support, (2) a silver halide emulsion layer on one side of the support, and (3) a conductive layer serving as an antistatic layer on the opposite side of the support. A photographic film comprising the conductive layer,
Comprising a film-forming binder and acicular, crystalline, single-phase conductive metal-containing particles, wherein the particles comprise 0.02
having a diameter of less than μm and an aspect of greater than 3: 1;
The conductive layer forms a colloidal dispersion by dispersing the needle-like particles using a polymer pulverizing medium having an average particle size of less than 350 μm, and the colloidal dispersion and the film-forming binder are combined. A photographic film formed by forming a mixture, coating the mixture on the support, and drying the mixture to form the conductive layer.

[14] (1) a support, (2) a silver halide emulsion layer on one side of the support, (3) a conductive layer serving as an antistatic layer on the opposite side of the support, and 4) A photographic film comprising a friction-resistant backing layer located on the conductive layer, wherein the conductive layer comprises:
Comprising a film-forming binder and acicular, crystalline, single-phase conductive metal-containing particles, wherein the particles comprise 0.02
having a diameter of less than μm and an aspect of greater than 3: 1;
The conductive layer forms a colloidal dispersion by dispersing the needle-like particles using a polymer pulverizing medium having an average particle size of less than 350 μm, and the colloidal dispersion and the film-forming binder are combined. A photographic film formed by forming a mixture, coating the mixture on the support, and drying the mixture to form the conductive layer.

[15] (1) a support, (2) a silver halide emulsion layer on one side of the support, (3) a conductive layer on the opposite side of the support, serving as an antistatic layer, and 4) A photographic film comprising an antihalation layer located on the conductive layer, wherein the conductive layer comprises:
Comprising a film-forming binder and acicular, crystalline, single-phase conductive metal-containing particles, wherein the particles comprise 0.02
having a diameter of less than μm and an aspect of greater than 3: 1;
The conductive layer forms a colloidal dispersion by dispersing the needle-like particles using a polymer pulverizing medium having an average particle size of less than 350 μm, and the colloidal dispersion and the film-forming binder are combined. A photographic film formed by forming a mixture, coating the mixture on the support, and drying the mixture to form the conductive layer.

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Ibrahim Michael Schalhoub New York, USA 14534, Pittsford, Stonington Drive 51

Claims (1)

[Claims] 1. An imaging element comprising a support, an imaging layer overlaid on said support, and a conductive layer overlaid on said support, said conductive layer comprising a film-forming binder. And needle-like,
Comprising crystalline, single-phase conductive metal-containing particles, wherein the particles have a diameter of less than or equal to 0.02 μm and an aspect of greater than or equal to 3: 1, and the conductive layer has an average particle size of less than 350 μm Using a polymer pulverizing medium, the needle-like particles are dispersed to form a colloidal dispersion system, and the colloidal dispersion system and the film-forming binder are combined to form a mixture, and the mixture is formed on the support. An imaging element formed by coating and drying the mixture to form the conductive layer.