DE2326334A1 - PHOTOGRAPHIC MATERIAL WITH AN ANTISTATICALLY EFFECTIVE, ELECTRICALLY CONDUCTIVE LAYER - Google Patents

Description

Photographic material with an antistatic, electrically conductive layer

The invention relates to a photographic material with a hydrophobic dielectric layer support, one antistatic effective, electrically conductive layer with a surface

resistance less than 10 ohms per square caused by oxidation can be converted into a comparatively less conductive layer with a comparatively lower optical density, at least a radiation-sensitive layer and, if necessary, adhesive, intermediate and / or top layers.

It is known that in photographic recording materials with at least one radiation-sensitive emulsion layer, which is arranged on a dielectric substrate, the ■ accumulation of static charges on the substrate to undesirable If a discharge occurs, the undesired effects usually result in a concealment of the effects Emulsion layer exist in the vicinity of the discharge. The accumulation static charges has a particularly disadvantageous effect in the case of roll films which do not have any gel pelloid layers or Have intermediate paper layers, which is often the case with roll films that are supposed to have a particularly low weight, or in the case of roll films intended for a rapid development process.

e.g. from BR-PS 309 659,
It is known to use / for dissipating electrostatic charges or for preventing the formation of electrostatic charges on dielectric photographic substrates, thin metal layers which have sufficient conductivity to prevent the formation of high localized static charges. A disadvantage of these metallic antistatic layers, however, is that if they are used in the form of thin films with a thickness of less than a few 100 Å units, they are easily oxidized during storage, so that their conductivity and thus their antistatic properties are quickly lost. In contrast, if such a metal layer is produced with a thickness sufficient to permit a decrease

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To avoid conductivity, this increased thickness leads to an undesirable increase in optical density. Further It has been found that some metals with photographic layers are subject to fogging and desensitization of the layers react and that some metals, e.g. B. bismuth and manganese can react in an undesirable manner with the substrate. Another disadvantage of using metallic, antistatic layers is that a layer support is with a freshly deposited antistatic metal layer, the metal layer often also on the other Adheres to the side of the substrate, so that the metal layer can lead to blocking, i.e. H. a prevention of trouble-free Unwinding of the film support, the metal layer often from one side of the support to the other Page can be transmitted while unwinding.

It is also known to use a wide variety of optical articles, z. B. Lenses and lens systems, windows and windshields, using metal and metal halide layers to manufacture. It is for example from the USA patent 3,330,681 known the reflection of plastic optical objects by using a metal layer and a metal halide layer to diminish. It is also known from US Pat. No. 2,852,415, by intimate mixing of metals and metal halides to produce layers on silica or silicate surfaces with the desired conductivity and adhere to the surfaces.

The object of the invention is to provide a photographic material with a hydrophobic dielectric layer support and at least specify a radiation-sensitive layer that is effectively protected from the accumulation of electrostatic charges, without the protection being lost when the material is stored or that a layer with an undesirably high optical density is accepted as a result of the antistatic treatment

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got to. A photographic, antistatic material was to be created in a very special way, its electrical Conductivity is not lost during storage and use. Furthermore, a photographic material should be created that is so antistatic that no special treatment to reduce its optical Density is required.

The invention was based on the knowledge that the problem posed can be achieved with a layer system that has at least consists of two layers, namely at least one electrically conductive layer, which by oxidation in one less conductive, optically less dense state can be transferred, and a protective metal halide layer, which the Can prevent or at least reduce oxidation of the electrically conductive layer in the atmosphere and which for oxidizing aqueous solutions is permeable and thus enables the oxidation of the electrically conductive layer.

The invention thus relates to photographic material with a hydrophobic dielectric layer carrier “one antistatic effective, electrically conductive layer with a top

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Surface resistance of less than 10 ohms per square, which can be converted by oxidation into a comparatively less conductive layer of a comparatively lower optical density, at least one radiation-sensitive layer and optionally adhesive, intermediate and / or cover layers, which is characterized in that at least that side of the electrically conductive layer facing away from the support is covered with a protective layer which is permeable to oxidizing aqueous solutions and consists of a metal halide layer.

The electrically conductive layer should preferably have a surface resistance less than 10 ohms per square.

The protective layer consisting of a metal halide layer prevents oxidation of the conductive layer during the

up to
Storage of the material sSudysiixx its use, however, is permeable to aqueous oxidizing solutions, so that the electrically conductive layer can be converted into an optically less dense state by oxidation if the photographic material is treated in a conventional aqueous photographic working solution, for example a developer or Fixing solution and / or a bleach and / or break bath. The invention thus enables the production of photographic materials which are protected from the accumulation of localized static charges, and when the photographic materials are used after the development process, photographic images can be obtained which are not impaired in their quality by the high optical density of metallic, antistatic layers will.

The photographic materials according to the invention have binder-free, electrically conductive layers as well as one or more binder-free protective layers. Under a "binder-free Layer "is to be understood here as a layer which is free of organic binders, i.e. binders which are commonly used known way can be used for the production of photographic recording materials and from natural and synthetic polymeric binders and colloidal carriers can exist.

The electrically conductive layer can consist of any electrically conductive material which can be obtained by contacting with an aqueous photographic working solution for the photosensitive Emulsion layer or the photosensitive emulsion layers converted into an optically less dense state by oxidation can be. It is irrelevant whether the oxidation product itself has a lower optical density or whether the reduction the optical density of the layer is achieved by

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that the oxidation product by the action of the photographic Working solution is dissolved or at least partially in solution goes.

Metals are preferred due to their high conductivity used to produce the electrically conductive layers.

As particularly advantageous metals for producing the electrically conductive layers have become manganese, bismuth, copper, aluminum and silver have been shown to be easily oxidized to a state of lower optical density when they are in the form of thin layers. Since the electrically conductive layer in all cases, e.g. B. when the photographic Material is wound up, separated by the protective layer from the radiation-sensitive colloid layer, can be used for Metals can also be used to create the conductive layer, which would adversely react with the colloid layer, and particularly those metals which would do them alone used, would lead to a fogging or desensitization of the radiation-sensitive colloid layer.

According to the invention, a second protective one is also possible Layer to be arranged between the substrate and the electrically conductive layer. In this case, the electrical conductive layer, a metal can also be used, which, if it were applied alone or directly to the substrate, would react with this. For example, metals such as manganese and Bismuth can be used, although these two metals are known to obscure photosensitive silver halide emulsions are capable when they are brought into direct contact with corresponding emulsion layers and which react in an undesirable manner with film layer supports made up of polymers, when applied directly to them.

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In order to ensure adequate protection against the accumulation of static electricity, it has been found necessary that the electrically conductive layer has a surface resistance of less than 10 ohms per square. Preferably it should have a resistance of less than 10 ohms per square. In order to ensure that a surface resistance of less than 10 ohms per square is achieved everywhere, it has proven advantageous if the conductive layer has a total surface resistance of less than 10 ⁵ ohms per square. With electrically conductive layers having a surface resistance of less than 10 ohms per square, particularly uniform photographic reproductions can be obtained without optical changes being discernible which are due to localized discharges of electrostatic charges.

The surface resistance of the layers can be determined by measuring the Resistance between two mutually parallel electrodes of equal length, their distance from each other Length corresponds to be determined. (See the book by Maissei and Glang "Handbook of Thin Film 'Technology", Verlag McGraw-Hill (1970), pages 13-5 to 13-7 ..), As an increase in the Length of the electrodes leads to a reduction in resistance by an amount equal to the amount by which the surface resistance by increasing the distance between. Electrodes by a corresponding increment, it is obvious that the electrode length and the Electrode spacing are not material as long as they are the same. As a result, the surface resistance is expressed in ohms per square, a resistance, determined for the special case in which the electrode length and electrode spacing are identical and consequently are mutually canceling parameters.

The electrically conductive layer is preferably not thicker than to achieve the desired conductivity properties

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is required. Such conductivities can be achieved with metal layers a thickness of less than 100 Å, preferably less than 50 Å. The reason that the layer thickness of the electrical conductive layer is to be limited, depending on the special material used in the individual case, is based on the fact that the electrically conductive material and / or one or more of its oxidation products can enter the aqueous photographic working solution, both for the development of the radiation-sensitive Colloid layer and at the same time used to reduce the optical density of the conductive layer can. Limiting the thickness of the electrically conductive layers reduces the amount of metal that is in the working or developing solution can occur, and the effectiveness and lifespan of the working or development solution is extended accordingly. Although the thickness of the electrically conductive layer can be well over 100%, depending on the individual case metal used and / or the resulting oxidation product, which can enter the photographic working solutions, as well as the volume and the desired purity of the working solution, it has been shown that usually layer thicknesses of over 1000 Ä are not required or appropriate.

It was surprising to find that the solution of the invention underlying task uses protective layers which prevent the electrically conductive layers from oxidizing during storage and use are able to protect and which furthermore cause an oxidation of the electrically conductive layers with the transfer of the same in an optically less dense form in the course of the photographic Enable the development process by means of aqueous solutions. A photographic material according to the invention thus contains at least a protective layer for the electrically conductive layer to prevent oxidation of the conductive layer is able to, however, compared to aqueous oxidizing solutions, which in the course of photographic development processes

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are required, is selectively permeable and thereby a reduction the optical density of the electrically conductive layer allows.

The protective layers used according to the invention, which the desired have selective permeability to oxidizing aqueous solutions, are binder-free layers of metal halides, e.g. metal fluorides and metal chlorides. The protective layers preferably consist of or essentially consist of an Metal fluorides.

Halides of group II A have proven to be particularly advantageous metal halides for producing the metal halide layers of the Periodic Table of the Elements and the halides of the rare earth metals, in particular the fluorides the metals of group II A of the periodic system of the elements and the rare earth metals, e.g. magnesium fluoride, Ceruos fluoride, calcium fluoride and barium fluoride proved. A Another particularly advantageous fluoride is sodium aluminum fluoride, also known as cryolite.

The protective layers should preferably have a thickness of less than 500 Å, in particular a thickness of less than 50 Å, in particular if the storage of the photographic recording material is to be expected before development or treatment in an aqueous oxidizing solution. The density of metal fluoride layers can increase somewhat with storage. The use has proven to be particularly advantageous proved by metal fluoride layers of a layer thickness of less than 50 Å, which in all cases is easily oxidized by aqueous Solutions can be penetrated. The protective metal halide layers remain in the developed photographic Material, these suitably have optical densities of less than 0.5 and are preferably practically transparent, i. have optical densities less than 0.01. In those cases in which the protective layer in the course of the photographic

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The winding process is completely removed, which is generally the case, affects the optical density of the protective layer the developed photographic material did not.

According to one embodiment of the invention, the electrically conductive Layer bonded directly to the dielectric substrate and the protective layer is located directly on the electrically conductive layer. In this case, the substrate protects a surface of the electrically conductive layer, whereas the protective layer the other surface of the electrically conductive. Layer protects.

In those cases where the substrate itself is responsible for oxidizing agents is permeable and / or in those cases in which the substance forming the electrically conductive layer coexists with the layer carrier material able to react, it has proven to be advantageous to place a second protective layer between the support and to arrange conductive layer. According to a further embodiment of the invention, this second protective layer can be the same Structure like the first protective layer. It should be noted that since the first protective layer for aqueous oxidizing Solutions is permeable, it is not necessary that the second protective layer is permeable in a corresponding manner. Accordingly, the second protective layer can be thicker than the first protective layer, for example up to about 1000 Å. However, it preferably has a layer thickness of less than 500 S. / "

If possible, the second protective layer should have an optical density of less than 0.5. In particularly advantageous Indeed, like the first, the second protective layer is practically transparent, i. H. it has an optical density of less than 0.01. The second protective layer is made up of a metal halide that is formed in the course of the photographic development process can be removed, so affects the optical seal / "The second protective layer can also consist of a practically insoluble Metal oxide, e.g., silicon dioxide, silicon monoxide, aluminum oxide, magnesium oxide, titanium dioxide, boron silicon oxide or tantalum oxide be constructed.

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This second layer did not affect the appearance of the final product.

The support of the photographic material of the invention can be any of the conventionally known photographic ones The substrate is dielectric, i.e. the one

8 surface resistance of at least 10 ohms per square,

12th
typically above 10 ohms per square.

Typical dielectric substrates used in the manufacture of a photographic Materials according to the invention can be used, for example, layers of glass, paper, wood, Rubber and the like. Of particular importance are those made of polymers Layer supports land the usual known ones, with polymers coated substrate.

Typical hydrophobic polymers that make up the base photographic Materials constructed according to the invention are, for example, cellulose esters, e.g. B. cellulose nitrate and cellulose acetate, Polyvinyl acetal polymers, polycarbonates, polyesters, e.g. B. linear polyesters of bifunctional saturated and unsaturated aliphatic and aromatic dicarboxylic acids and

bifunctional organic polyhydroxy compounds, e.g. B. multiply valued alcohols, e.g. B. polyester from alkylene glycol] / and / or Glycerine with terephthalic acid, isophthalic acid, adipic acid, maleic acid, Fumaric acid and / or azelaic acid, also polyhalohydrocarbons, z. Polyvinyl chloride, and finally polymeric hydrocarbons, e.g. B. polystyrene and polyolefins, in particular Polymers of olefins having 2 to 20 carbon atoms. The polymers described can be in the form of flexible film supports or rigid substrates or for coating glass, paper and polymer substrates. from Of particular importance are those coated with ct-01efin polymers Paper backing, e.g. B. paper backing made with polyethylene, polypropylene or ethylene-butene copolymers have been coated.

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2328334

If the surface of hydrophobic to be coated film base / to improve the adhesion of the radiation-sensitive hydrophilic colloid layer on ^e IFTF ^r hydrophobic surface of the support it can be advantageous, before the radiation-sensitive colloid layer is applied to apply a so-called. Subbing layer on the support. For example, in the case of polyester substrates, e.g. B. those made of polyethylene terephthalate, proven to be advantageous, an adhesive layer of a terpolymer made of acrylonitrile or a short-chain acrylic acid alkyl ester with less than 4 carbon atoms in the alkyl radical, a vinylidene halide and acrylic acid, z. B. acrylonitrile or methyl acrylate, vinylidene chloride and acrylic acid to apply.

The layer system used according to the invention composed of electrical The conductive layer and the metal halide layer can be applied directly to such an adhesive layer or else directly onto it the hydrophobic polymer surface, as the metals that are used to create the conductive layer, as well as the metal halides / those for producing the second protective layer can be used to adhere firmly to such substrate surfaces.

Indeed, it is surprising that the one used according to the invention antistatic layer system adheres firmly to hydrophobic polymer surfaces.

The electrically conductive layers and metal halide layers can be applied to the substrate using known methods. It has proven to be advantageous to apply the electrically conductive layers and protective layers to the substrate by means of a cup coating in a vacuum. One Vacuum vapor deposition is an easy-to-use process that makes it possible to determine the thickness of the layer to be applied Strictly adhere to layers. Vacuum steam also enables

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coating that the protective layer directly on the electrical conductive layer can be applied without the electrically conductive layer being exposed to the action of the atmosphere. This causes the formation of an oxide layer avoided on the surface of the electrically conductive layer, it is known that certain metals, in particular aluminum, when exposed to air, they easily form oxidic layers. Such oxidic layers can however interfere with the oxidation of the electrically conductive layer in order to reduce its optical density. For example, antistatic aluminum layers which are used without a protective layer cannot easily be replaced by dielectric ones Layer supports are removed or made transparent, even if they are brought into contact with aqueous alkaline solutions with a pH of above 11. in the In contrast to this, electrically conductive layers made of aluminum that have been obtained by vacuum vapor deposition of a layer support and those with a selectively permeable protective layer can be used have been coated according to the invention without the aluminum layer being exposed to the action of air, easily and quickly made transparent using conventional aqueous alkaline working solutions having a pH of over 9 but less than 11. This means that the ease with which the optical density of the electrically conductive Layer can be reduced, is promoted by preventing the formation of surface oxides.

The radiation-sensitive layer can under

Use of one or more hydrophilic, water-permeable Colloids, which can be natural or synthetic in origin. Typical hydrophilic colloids for producing the radiation-sensitive colloid layer are, for example, proteins, e.g. B. gelatin and gelatin derivatives, cellulose derivatives, polysaccharides, e.g. B. dextran, gum arabic and the like., as well as such synthetic polymers as those soluble in water

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Polyviny! Compounds, ζ. B. polyvinyl pyrrolidone and acrylamide polymers.

Additional build-up of the radiation-sensitive colloid layer can further customary known hydrophilic colloids can be used together with those synthetic polymers which contribute to the dimensional stability of the radiation-sensitive colloid layer. Such synthetic polymers are for example in the United States patent statutes 3,142,568, 3,193,386, 3,062,674, 3,220,844, 3,287,289 and 3,411,911. Particularly effective polymers which increase the dimensional stability of the colloid layers have proven to be water-insoluble polymers made from alkyl acrylates and alkyl methacrylates, acrylic acid and sulfoalkyl acrylates or sulfoalkyl methacrylates, as well as polymers with crosslinking centers that cause hardening or aging of the Facilitate polymers, e.g. B. that from the United States patent 3,488,708 known type, and also those which have recurring sulfobetaine units, such as are e.g. B. from Canadian patent 774 054 are known.

The hydrophilic colloids can be hardened in a conventionally known manner by means of organic or inorganic hardening agents. For curing, for example, alone or in combination Hardening agents consisting of aldehydes or so-called blocked aldehydes, as described in US Pat. No. 3,232,764, as well as ketones and carboxylic acid derivatives, sulfonate esters, sulfonyl halides and vinyl sulfonyl ethers, such as those from the US Pat 3,539,644 are known, and active halogen compounds, also epoxy compounds, aziridines, active olefins, isocyanates, carbodiimides, also polymeric curing agents, e.g. B. oxidized polysaccharides, ζ. B. dialdehyde starch and oxyguar gum and the like.

The radiation-sensitive hydrophilic colloid layer can be one of the usual known ones for the production of radiation-sensitive / "" Carboxylic acid derivatives

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radiation-sensitive compounds used in photographic recording materials. The radiation-sensitive layer can be panchromatic or an orthochromatic layer or a layer which is sensitive only to X-rays, for example only to selected parts of the electromagnetic spectrum.

A photographic material according to the invention can do the same ren have only a single radiation-sensitive colloid layer, d. H. a colloid layer in which a photosensitive Compound is dispersed, optionally with customary known additives, as are customary for the production of photographic radiation-sensitive emulsion layers are used. On the other hand, the photographic material of the invention can be used have a plurality of colloid layers, with the proviso that all or only some of the layers can contain a radiation-sensitive compound. This means that, for example, the hydrophilic colloid layer closest to the substrate or the adhesive layer applied to it need not necessarily contain a radiation-sensitive compound, but rather that this radiation-sensitive compound can be contained in one or more layers that cover such a hydrophilic colloid layer are arranged. So For example, the photographic material according to the invention may consist of a photographic material intended for color photography There are recording material in which, as is known, a plurality of radiation-sensitive ^ colloid layers on a layer support are arranged, which are sensitized to certain sections of the visible spectrum. On such layers there may be additional intermediate layers of the cover layers which do not contain any heat-sensitive compounds. Typically, the hydrophilic colloid layer, which has been applied to the adhesive layer, e.g. £. on an iififtfc layer built up from a terpolymer, itself

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do not contain any radiation-sensitive compounds * Typical hydrophilic colloid layers which can be applied to a hydrophobic layer support or to an adhesive layer. this support and which do not contain any radiation-sensitive compounds, for example no silver halide for example consist of antihalation layers or germs containing layers, e.g. B. image receiving layers as they are in Conventional chemical transfer processes may be used, or dye mordant layers and the like.

The radiation-sensitive compounds used to produce the Photographic materials used in the invention can consist of various compounds, such as are sensitive to electromagnetic radiation. Typical radiation-sensitive compounds are, for example Silver salts, especially silver halides and zinc oxide.

However, the radiation-sensitive layers of a photographic material according to the invention can, for example, also consist of Layers of a radiation-sensitive polymer can be built up, e.g. B. a photosensitive polycarbonate resin. This means that also polymeric radiation-sensitive compounds can be used to build up the radiation-sensitive layers.

Photographic materials according to the invention based on silver halides, in particular those with at least one silver halide emulsion layer, are of particular importance. the Silver halide emulsion layers can contain the silver halide in the form of silver chloride, silver bromide, silver bromide iodide, silver chloride bromide, silver chloride iodide or silver chloride bromide iodide crystals or mixtures thereof. The emulsions used to produce the emulsion layers can be coarse-grained or fine-grained emulsions

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act, which can be prepared by customary known methods. This means that the emulsions are, for example can be so-called single enema emulsions, as described, for example, by Trivelli and Smith in "The Photographic Journal", Vol. LXXIX, May 1939, pages 330-338, are described, or so-called double enema emulsions, ζ. B. So-called. Lippmann emulsions, also ammoniacal emulsions or emulsions ripened in the presence of thiocyanates or thioethers, as they are, for example, in the USA patents 2,222,264, 3,320,069, and 3,271,157. Furthermore, for the production of the photographic of the invention Materials Negative type emulsions can be used as well as direct positive emulsions such as those in the United States patents 2,184,013, 2,541,472, 3,501,307, 2,563,785, 2,456,953 and 2,861,885 and British Patent Specification 723 019 and French patent specification 1,520,821.

Those for making the photographic materials of the invention Silver halide emulsions used can be sensitized in a customary known manner with chemical sensitizing agents be, for example with sensitizers consisting of reducing compounds, sulfur, selenium or Tellurium compounds or gold-r, platinum or palladium compounds or combinations thereof.

The radiation-sensitive layers can furthermore the contain conventional known additives, as are usually contained in radiation-sensitive layers of photographic recording materials. So can the photographic emulsion layers contain, for example, so-called development modifiers, as well as antifoggants and stabilizers, finally plasticizers and lubricants, optical brighteners, spectral sensitizers and color formers, as described, for example, in Sections IV, V, XI, XIV, XV and

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XXII are described the "Product Licensing Index", Vol, 92 ₀ December 1971, publication 9232 on pages 107-110.

As already stated ₉ , the photographic materials according to the invention can be developed with aqueous photographic developing solutions. However, the photographic materials according to the invention can also be those which are listed under. Avoiding aqueous developing solutions can be developed in a dry way. For example, the photographic materials according to the invention can also be those photographic recording materials based on silver halide, which are intended for recording copy-out images, such as those in US Pat. No. 2,369,449 and 3,447,927. Furthermore, the photographic materials according to the invention can be intended for the production of direct copy images and have a structure as is known, for example, from U.S. Patents 3,033,682 and 3,287,137. Finally, the erfiadungsgemäßen recording materials can also be such a let ₈ that develop ment process durch_ein called. Wärmgent- _B z. B. those which have an oxidation-reduction-image-generating combination with a photosensitive metal salt, eg "B" a silver salt, as are known, for example, from US Pat.

Optionally, the photographic materials according to the invention can additionally have, in addition to a metal halide layer and an electrically conductive layer _s , further customary known antistatic or conductive layers, ζ. B. layers of or with soluble salts, e.g. Bo chlorides or nitrates ^ or ionic polymers, as described for example in US Patents 2,861,056 and 3,206,312, or layers of or with insoluble inorganic salts, e.g. Of the type known from U.S. Patent 3,428,451.

~ 18 -

After exposure, photographic materials according to the invention can typically be in contact with alkaline and / or acidic aqueous solutions are brought, for example developing baths, which are for the purpose of silver reduction of silver halide emulsion layers are used and typically have a pH value above 9 "or with fixing baths that for the purpose of dissolving silver halides. from the colloid layers can be used and typically have a pH of less than 6.0, preferably less than 5.0.

An essential feature of this invention is that the photographic Working or developing solutions used to do this can be made to the electrically conductive layer by oxidation to be converted into an optically less dense © layer.

While it was previously known that certain _s metallic antistatic layers in the course of the photographic. Development process are oxidized, it is surprising to find that the conductive layers used according to the invention can be oxidized in these photographic working or developing solutions, since they

is protected from air oxidation by the protective layer.

The type and WEIS® and the degree to which _$ is the optical density of the electrically conductive layer reduces ₉ may be comparable eliminated, depending on, what is used for an aqueous oxidizing solution _s and depending on how the electrically conductive Layer and the protective layer are built up and depending on what thickness these layers have.

In most cases, both the electrically conductive layer and the protective layers are completely removed from the substrate removed so that the developed photographic material shows no increase in density due to the antistatic layer system. While in some cases the protective

u98 * a / ¹ ι 48

layer itself is dissolved by the .used ifäßrige oxidizing solution, z. Example, a Metallhalogenidschutzschicht by a complexing ,, 2, Bc, a phosphate ,, which is included in the design or working solution to be solved _s, but to assume that in most cases, the applied aqueous oxidizing solution initially penetrates the protective layer and the electrically conductive Layer oxidized »In the course of the oxidation of the conductive layer, its adhesion to the layer substrate is reduced, so that both the protective layer and the conductive layer are separated from the layer substrate»

Since the protective layers typically have a low optical density for metal halides, the protective layers can, however, also be left on the substrate If the layer system remains on the layer support after the photographic development process has been carried out, it should preferably have an optical density of less than O ₉ S »In most cases the layer system is completely removed or made practically transparent that is, it has an optical density of less than 0.01.

Another surprising feature of the invention is that certain metals, e.g. B ₀ aluminum, which are normally not oxidizable when they come into direct contact with photographic working or developing solutions, can easily be converted into an optically less dense state by oxidation if they are used in conjunction with a protective layer, which prevents the migration of metals, for example aluminum, in the air.

The photographic materials of the invention thus have the advantage that they have an antistatic layer system that is stable during storage or storage and that the optical density of this layer system in the course of the development process of the photographic material can be reduced without the need for additional processing steps are.

The drawing serves to explain the invention in more detail. 1 to 3 are photographic materials according to the invention shown schematically in section before implementation of the development process.

In detail are shown in:

Fig. 1 a photographic recording material 1, consisting of a dielectric substrate 3, preferably a film substrate consisting of a polymer, on which is applied are: a layer system 5 consisting of an electrically conductive layer 7 which is applied directly to the layer substrate, and a protective layer 9 on the electrically conductive layer and an adhesive layer 11 on the other side of the substrate and a photosensitive emulsion layer 13 over the adhesive layer 11;

Fig. 2 is a photographic recording material 15 shown in its structure corresponds to the recording material shown in FIG corresponds, with the exception, however, that an adhesive layer 17 zivischen the electrically conductive layer 7 and the substrate is arranged;

Fig. 3 shows a photographic material 19 which differs from the recording materials 1 and 35 of FIGS. 1 and 2 differs in that the adhesive layer 11 between the emulsion layer 13 and the substrate 3 is omitted

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and that the antistatic layer system 21 consists of one electrically conductive layer 23, a first protective layer and a second protective layer 27 between the electrically conductive Layer and the substrate.

The following examples are intended to illustrate the invention in more detail.

example 1

to the superior stability of a used according to the invention To illustrate the antistatic layer system in comparison to an unprotected metallic manganese layer, a Roll of polyethylene terephthalate film base, which has a conventional adhesive layer of a terpolymer of acrylonitrile or methyl acrylate, Vinylidene chloride and acrylic acid in a vacuum coater clamped. At the same time, magnesium fluoride was placed in a crucible of the coating device. The vacuum chamber of the coating device was then closed and until a negative pressure of 3.2 χ was achieved Pumped 10 Torr empty. The magnesium fluoride was then heated by means of an electron beam to a point at which it strongly sublimated. Now slide, which the layer carrier material before the exposure of the magnesium fluoride protected, opened, whereupon the substrate material was drawn at such a speed by the magnesium fluoride vapor It was found that magnesium fluoride could condense on the substrate to a thickness of 50 Å. After finishing the coating process and cooling the magnesium fluoride gel the negative pressure was released.

The layer support roll, which had a magnesium fluoride layer, was now rewound and powdered into the crucible Magnesium introduced. Then the vacuum chamber

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again pumped empty, whereupon the melting pot with the magnesium powder was heated. The support material was then pulled through the chamber again so that it was deposited on the magnesium fluoride layer could deposit a manganese layer. A manganese layer 60 Å thick was produced.

Half of the roll was coated again with a second layer of magnesium fluoride 50 feet thick, " which was applied to the manganese layer.

In a further experiment, a 60 A * thick layer of manganese was applied directly coated on a polyethylene terephthalate film support.

All coated substrates showed a surface resistance less than 10 ohms per square.

The manganese that was applied directly to the substrate was completely oxidized after the material had been left under normal conditions overnight. The substrate with a magnesium fluoride layer and a manganese layer applied thereon, which had not been covered, showed a slight increase in surface resistance when the material had been stored under normal conditions for two weeks, whereas the substrate with the manganese layer and two magnesium fluoride layers showed no change in the surface resistance characteristics showed. If the treated substrates were exposed to a relative humidity of 50% at a temperature of 50 ^° C. for 12 weeks, the surface resistance of the sample coated with a magnesium fluoride layer increased somewhat, but the surface resistance remained below 10 ohms per square. In the case of the test specimen with a manganese and a magnesium fluoride layer

1 ο

the surface resistance increased to 10 ohms per square, so high that no effective antistatic Properties were more present.

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In those cases in which the acrylonitrile residues are used to produce the adhesive layers containing terpolymer was used, the initial surface resistances were less than 10 ohms per Square, whereas when using adhesive layers made of the terpolymer containing methacrylate residues, initial surface resistances from 10 ötbGK to 10 ohms per square were measured. On the other hand, the two adhesive layers provided test specimens with comparable properties.

The antistatic layer systems described dissolved completely in less than a minute in a conventional aqueous alkaline developer solution with a pH of 9 to 10 and the composition given below:

Water, about 5O ⁰ C 500 ml

p-methylaminophenol sulfate '2.0 g

Sodium sulfite, dehydrated 90.0 g Hydroquinone 8.0 g

Sodium carbonate, monohydrate 52.5 g, potassium bromide 5.0 g

made up to 1 liter with cold water.

In a further series of tests, photographic gelatin-silver halide emulsion layers were applied to the modified layer base applied. It was found that the invention used antistatic layer systems are removed during the development process of the exposed recording materials without disturbing the development process or negatively affecting the quality of the photographic materials obtained was influenced.

Example 2

This example illustrates the preparation of a photographic Materials using an electrically conductive bismuth layer.

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According to the procedure described in Example 1, a · conventional cellulose acetate film support is a magnesium fluoride-bismuth-magnesium fluoride layer system applied. The method described in Example 1 was modified in such a way that the bismuth layer and the magnesium fluoride top layer in succession in one coating process using two means Electron beam heated crucibles was carried out. The thin film base material produced in this way had a 50 Å thick magnesium fluoride layer, a 70 Å thick bismuth layer and a 50 Å thick cover layer made of magnesium fluoride on.

The layer system turned out to be common aqueous alkaline Developer solutions considered insoluble, yet it got in less than a minute in a 2% acetic acid breaker bath dissolved at a pH of less than 6.

When fresh, the photographic material had a resistance of 4.2 χ 10 ohms per square. After a 10-week storage at 50 $ cent relative humidity and 50 ⁰ C, the surface resistance decreased to 5.0 χ 10 0hm to per square. Although this resulted in a certain change in the surface resistance of the layer system, the last measured surface resistance is still so low that excellent protection against static charges is achieved.

In a further series of tests, a radiation-sensitive gelatin-silver halide emulsion layer was applied to the antistatic Coating applied opposite side of the substrate. The material settled after exposure without any disadvantage develop through the antistatic layer system.

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Example 3

This example illustrates the use of a tier system with a conductive aluminum layer.

According to the method described in Example 1, aluminum layers of various thicknesses were applied to a polyethylene terephthalate film support, and magnesium fluoride layers were then applied directly to the aluminum layers produced. The surface resistances of the coated materials were then determined, whereupon samples of the. coated materials at a relative humidity of 50 % and a temperature of 50 ⁰ C were stored. After a storage period of 3 or 8 months, the surface resistances were measured again. The results obtained are shown in Table I below.

Table I.

Thickness of the Layers in Ä Fresh
material Surface resistance in
Ohms / square To
8 months Al-
layers MgF ₂ -
layers 25th To
3 months 700 37 31 65 100 4,000 34 62 40 1,800 2,600 40 83 25th 320 120 66 38 200 58 > 10 ¹² 22nd 35 2.0 χ 10 ⁵

All layer systems, with the exception of the system with the thinnest Aluminum layer, showed an excellent after 8 months Surface resistance. But also the rail system with the thinnest aluminum layer showed after 3 months of storage another satisfactory surface resisted.

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In further experiments, test items of the materials produced were bathed in an aqueous alkaline developer solution of the composition given in Example 1 with a pH value of 9 to 10 and a temperature of 23 ° C, namely immediately after their preparation and after a 3- month's retention period. In this series of tests, a support with an 'unprotected aluminum layer was included.

ff

In the following table II the times required for the complete dissolution of the layer systems are given in minutes.

Layers in Table II To completely loosen the layers
systems time required in minutes 3 month old
material Thickness of the MgF ₂ layer A. Fresh
material 3.5 Al-
layer 31 3.5 > 10.0 37 62 2.5 > 10.0 34 83 3.5 5.0 40 38 5.0 1.3 66 35 1.3 5.0 22nd 50 3.5 > 10.0 50 - 5.0 50

In all those cases in which the protective layer had a thickness of less than 50, there was no discernible increase in the time required for the layer system to detach from the substrate. In cases where the protective layer had a thickness of about 50 K, there was a slight increase in the amount of time that was required to remove the Schichtensysten.s revealed. When comparing materials with aluminum layers of the same thickness, it can be observed that the protective layer reduces the time required for the removal of the aluminum layer, both in the case of a

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fresh material as well as in the case of one that has been stored for 3 months Materials. Although longer periods of time are required to build stratification systems with protective magnesium fluoride coatings Completely removing thicknesses of over 50 A * does arise from Table I that these layer systems have satisfactory surface resistance values iron on for longer periods of time and easily removable from fresh material. Although furthermore, these layer systems are not completely in less than 10 minutes after 3 months of storage, their optical densities become considerable within that Time span reduced. Corresponding results will then be obtained when aluminum is deposited on a cellulose acetate film support. Since aluminum does not use film backing materials reacts, no protective sub-layer is required between the substrate and the aluminum layer.

In a broader series of tests, a Gelatin-silver chlorobromide emulsion layer applied. Such Recording materials showed excellent protection from static discharges, as the surface resistance

such materials were below 10 ohms per square. The photographic Characteristics were neither impaired nor impaired by the presence of the antistatic layer system by removing the antistatic layer system »

Example 4

This example illustrates the use of an antistatic layer system made of a conductive silver layer and a magnesium fluoride protective layer.

In a vacuum coating device in which the material to be vapor-deposited on the substrate material could be vaporized by means of an electron beam, a set of rollers was installed around which an endless belt made of a plastic ^;

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Film base material could be performed. The roles left propel themselves through a clutch system and a mechanical drive system outside the vacuum chamber. The endless tape could be moved behind an opening in a mask between the underside of the tape and the container with the material to be evaporated was arranged. The opening was covered by a slider.

In the case of this example, the endless belt consisted of a polyethylene terephthalate film base. Into the crucible pure silver was added to the coating device, whereupon the vacuum chamber was pumped empty to a pressure of 3.0 10 Torr. The silver was made using an electron beam heated to the point of vaporization, whereupon the substrate was allowed to run around the rollers at such a speed that every point of the support passed the opening 20 per minute. After the slide opens over the opening had been, the silver was deposited on the layer support in a layer thickness of 25 λ. Thereupon the slider closed again, whereupon, after the crucible with the silver had cooled down, the chamber was brought back to atmospheric pressure became.

Magnesium fluoride has now been introduced into the crucible, whereupon a mask was applied to the opening in such a way that only one half of the substrate could be exposed ". The chamber was again pumped out to a pressure of 3 × 10 Torr, whereupon half the width of the substrate material was coated with a magnesium fluoride layer with a layer thickness of 50 a.

Samples of the coated materials were then used for 6 weeks Exposed to 50% relative humidity at 50 ° C. The in The surface resistances determined for fresh materials and stored materials are shown in Table III below compiled.

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Table III

Warehouse properties

Fresh After 6 weeks long storage material

Layer type surface resistance in

resistance in ohms / square

Ohms / square

only silver 28> 1O ¹²

Ag + MgF ₉ 25 60 "

Both sections of the coated polyethylene terephthalate film support were found to be insoluble in aqueous alkaline developer solutions. However, it was found that the optical density both the unprotected silver layer and the silver layer protected by a magnesium fluoride easily by action a conventional bleach bath could be reduced, for example an aqueous sodium ferricyanide bleach bath from U.S. Patent 3,046,129.

Silver halide deposited on the film material during treatment in the bleach bath easily underwent Use of a conventional fixing bath based on sodium thiosulphate with a pH value of less than 6, for example a bath of the following composition:

Water, about 50 ° C 600 ml

Sodium thiosulfate 240.0 g

Sodium sulfite, dehydrated "15.0 g

Acetic acid, 28% 48.0 ml

Boric acid, crystalline 7.5 g

Potassium alum "15.0 g

made up to 1.0 liter with cold water

remove.

The silver halide was created by converting sodium bromide the bleach bath with the silver of the conductive layer,

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The antistatic layer system was completely in the course a photographic development process and in no way interfered with the optical density of the developed photographic material. The magnesium fluoride protective layer did not in any way interfere with the solution of silver in the photographic working solutions.

Example 5

According to the method described in Example 4, a 60 Å thick layer of silver applied. Cerium fluoride was introduced into the crucible, which can be heated with an electron beam.

On half a side of the support was then a 200 Å thick layer of cerium fluoride vapor deposited.

In further experiments, 60% thick silver layers were deposited on polyethylene terephthalate layers, whereupon these were coated with a 400 Å * thick calcium fluoride layer, a 300 Å barium fluoride layer or a 400 Å thick aluminum sodium fluoride layer (cryolite not).

In all cases the metal fluoride overcoat protected the silver layer before abrasion and before degradation during storage,

All of the materials produced had a surface resistance of! less than 10 ohms per square, i.e. an upper surface resistance, which is more than sufficient to impart excellent antistatic properties to the material.

The layer systems proved to be insoluble in a developer of the type specified in Beir-niel 1, but could be in less than 10 seconds in a bleach bath as in Example 4

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bleach specified composition. The silver bromide that formed in the bleach bath dissolved in less than 5 seconds, In the fixing bath of the specified composition.

In further experiments xnirden on polyethylene terephthalate substrates Electrically conductive copper layers deposited in the manner described, as well as protective metal fluoride layers. In all cases, surface resistivities were found to be less than 10 ohms per square in the case of freshly coated ones and over longer periods Observe material stored for periods of time. The xfurther the optical density of these layer systems could easily be reduced by means of aqueous oxidizing photographic working solutions.

In a further series of tests, the substrate sides, which had not been coated, applied radiation-sensitive colloid layers. In all cases it was found that the photographic recording materials obtained had excellent static protection. Also were the photographic properties of the materials neither by the presence of the antistatic layers nor by the removal of these layers during the development of the materials adversely affected.

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Claims (20)

PATENT CLAIMS Photographic material with a hydrophobic dielectric layer support, an antistatic, electrically conductive one Layer with a surface resistance of less than 12th 10 ohms per square caused by oxidation in a comparatively less conductive layer of a comparatively lower one optical density can be transferred, at least one radiation-sensitive layer and optionally adhesive, intermediate and / or cover layers, characterized in that at least the side facing away from the layer support is electrically conductive layer with a protective layer which is permeable to oxidizing aqueous solutions and consists of a metal halide layer is covered. 2. Photographic material according to claim 1, characterized in that that the metal halide layer has a thickness of less than 500 Å, in particular less than 50 Å. 3. Photographic material according to Claims 1 and 2, characterized in that that there is a layer of a halide of a metal from group II A of the periodic table as the metal halide layer containing elements, a rare earth metal or cryolite. 4. Photographic material according to Claims 1 to 3, characterized in that that it has a layer of a metal fluoride as the metal halide layer. 5. Photographic material according to claim 1, characterized in that that it has a second protective layer between the electrically conductive layer and the substrate. 309848/1148 6. Photographic material according to claim 5, characterized in that that the second protective layer is transparent or has an optical density of less than 0.5. 7. Photographic material according to claims 5 and 6, characterized in that, indicates that the second protective layer also consists of a metal halide layer or a metal oxide layer or Metal halide-metal oxide layer consists. 8. Photographic material according to Claims 1 to 7, characterized in that that it has a film base made of a polymer. 9. Photographic material according to claim 8, characterized in that that it is a polyester or cellulose ester film backing having. 10. Photographic material according to claim 9j, characterized in that it is a support made of a polyalkylene terephthalate or cellulose acetate. 11. Photographic material according to claim 1, characterized in that that there is an adhesive layer between the support and the radiation-sensitive colloid layer. 12. Photographic material according to claim 1, characterized in that that it has an electrically conductive layer made of an oxidizable metal. 13. Photographic material according to Claims 1 and 12, characterized in that that the electrically conductive layer has an upper sheet resistance of less than 10 ohms / square, in particular 'is less than 10 ohms / square. 309848/1148 14. Photographic material according to claim 12, characterized in that that it has a layer of silver, aluminum, bismuth, manganese, copper or mixtures thereof. 15. Photographic material according to claim 4, characterized in that that it has a metal fluoride layer consisting of magnesium fluoride or sodium aluminum fluoride. 16. Photographic material according to claim 1, characterized in that that the electrically conductive layer and the metal halide layer consist of binder-free, vacuum-deposited layers. 17. Photographic material 'according to claim I _9, characterized in that it has, as a radiation-sensitive layer, a SiI oversalt layer, in particular a silver halide emulsion layer. 18. Photographic material according to claim 17, characterized in that that the radiation-sensitive colloid layer is a silicon bromide chloride emulsion layer having. 19. Photographic material according to Claims 1 to 16, characterized in that that there is an aluminum layer free of surface oxides as the electrically conductive layer and as a metal halide layer has a magnesium fluoride or sodium aluminum fluoride layer. 20. Photographic material according to claim 1, characterized in that that the electrically conductive layer has a thickness of less than 1000 Å. 3098U / 1U8