DE68924476T2 - Photographic element and its production. - Google Patents

Description

BACKGROUND OF THE INVENTION

The invention relates to a photographic recording material with a layer support, at least one image carrier layer located on the layer support and also a protective layer, as well as a method for producing the same. In particular, it relates to a photographic recording material that is easy to produce and in which excellent adhesion to the image-forming layer and outstanding water resistance are ensured. The photographic recording material according to the invention can also be used well, in particular for an identification card, for example.

So-called identification cards, e.g. employee ID cards, credit cards, driving licenses and access authorizations, were generally those with the required predefined information, for example printed details (information) such as address, name and number, on a layer carrier made of, for example, paper, plastic and the like, and further identification information, e.g. a photograph for identifying the person, with a seal or stamp. The disadvantage of such identification cards, however, is that they can easily be counterfeited, e.g. copied, altered and the like. Furthermore, they are not very durable, e.g. often susceptible to friction and the like and soiling, breaking and the like when worn for long periods of time. To improve these deficiencies, a light-sensitive recording material with a light-sensitive emulsion, e.g. silver halide emulsion, on a layer carrier has recently been used. Details or details are printed on this light-sensitive recording material in the same way that a person's head picture is copied onto it. There are also a wide variety of "counterfeit-proof"cards. Identification cards, such as those in which the surface is coated with a resin film and then heat-sealed, those in which both surfaces are laminated with a resin film, and the like. However, these can also be altered by peeling off the emulsion surface and the resin film of the photosensitive recording material. Thus, there is no completely forgery-proof identification card. In addition, there is also the risk of discoloration, which causes durability problems. Cards bonded or laminated to a resin film suffer from the need for complicated devices such as a hot-melt or laminating device and complicated processing steps, so that inexpensive identification cards cannot be produced.

In order to counteract these disadvantages, a technique has become known in which a mass curable by active radiation is applied to the image-forming layer and the mass is then cured with active energy radiation to form a layer-like protective coating.

In order to produce a protective layer by hardening using active radiation energy, measures have become known for forming layer-like protective coatings that can be hardened by UV radiation in order to ensure scratch resistance, abrasion resistance, tarnishing resistance and the like of the photographic recording material after image formation. Japanese Unexamined Patent Publication No. 57023/1978, U.S. Patent Nos. 4,171,979, 4,049,861 and 4,333,998, Japanese Unexamined Patent Publication Nos. 121100/1978 and 91233/1981 and Japanese PCT Unexamined Patent Publication No. 501642/1984 disclose a method in which a composition comprising an acrylic prepolymer having unsaturated groups and a photoradical-forming polymerization initiator are coated for subsequent curing by radical polymerization, and a technique in which a combination of an epoxy resin, an acrylic Prepolymer, a cationic polymerization initiator and a radical chain polymerization initiator. Although these protective layers can be used to sufficiently improve the abrasion of the films for projection purposes and the handling of the film copies, this technology is in no way suitable for the production of identification cards. The characteristic requirements of identification cards, in particular water resistance and adhesion, cannot be sufficiently achieved or guaranteed.

In particular, when an active energy radiation-curable resin is used to produce the protective layer on a photographic silver halide emulsion, adhesion to the emulsion layer is generally problematic for acrylic polymers, so that an intermediate layer is sometimes required. As a means of improving adhesion, processes have already been disclosed in which acrylate oligomers and compounds having reactivity with or affinity for gelatin are used in combination (see Japanese Unexamined Patent Publications Nos. 201248/1986, 201250/1986, 201249/1986 and 201251/1986). Adhesion may be improved somewhat in this way, but it is still insufficient. In addition, light resistance is also still poor, so that acceptable photographic performance is inevitably not achieved. On the other hand, it has been shown that the epoxy polymer can sometimes be difficult to cure due to the sodium sulfite.

Examples of the use of curable coating layers on compositions containing epoxy resins and cationic polymerization initiators for identification cards are given in Japanese Unexamined Patent Publications Nos. 90489/1982, 21150/1987, 23042/1987, 23043/1987, 24256/1987, 25758/1987 and 229133/1987. However, in the various conditions of use of identification cards, it is impossible to obtain all the required properties in terms of adhesion, water resistance, pitting and contamination resistance when damaged. The techniques described require a very large curing device to meet all of the above requirements, so that it is difficult to easily produce a low-cost card.

Another technique for improving adhesion using an acrylate oligomer and an epoxy polymer is known from Japanese Unexamined Patent Publication No. 229133/1987. In this technique, a special film hardener is used in a layer adjacent to the UV-curable layer. As the amount of film hardener increases, the (desired) effect improves, but at the same time the photographic sensitivity deteriorates.

The present invention was made against the background of the various difficulties described above. Its object is to provide a photographic recording material whose layer-like protective coating is produced by hardening using active energy radiation, namely 1. a photographic recording material with good adhesion of the image-forming layer and the like and good water resistance, and 2. a photographic recording material which also produces acceptable images with good adhesion and water resistance without impairing light resistance and sensitivity. A further object is to create a simple and inexpensive method for producing such a photographic recording material by irradiation with low-energy active energy radiation.

The present invention relates to a photographic recording material with a layer support, at least one image-bearing layer thereon and a protective layer on the image-bearing layer, the protective layer being one such which is prepared by curing an active energy ray-curable epoxy composition comprising a prepolymer having at least two epoxy groups from a combination of an aromatic epoxy resin, an alicyclic epoxy resin and an aliphatic epoxy resin, and an active energy ray-activatable polymerization initiator by irradiation with active energy ray, and wherein the image-bearing layer has a water content of 20.0 wt% or less.

The present invention further relates to a process for producing a photographic recording material with a layer support, at least one image-bearing layer on the layer support and a protective layer, by

Application of at least one image-bearing layer to the substrate;

Forming an image on the image-bearing layer; Applying an epoxy mass curable by active energy radiation and a polymerization initiator activatable by the active energy radiation to the resulting image-bearing layer and

Irradiating the curable epoxy composition with active energy radiation, wherein the curable epoxy composition comprises a prepolymer having at least two epoxy groups from a combination of an aromatic epoxy resin, an alicyclic epoxy resin and an aliphatic epoxy resin and the image-bearing layer has a water content of 20.0% by weight or less.

With the help of the measures described, a photographic recording material can be produced in an acceptable manner which guarantees good adhesion and water resistance on the one hand and good photographic properties (images) on the other, which were only achievable with difficulty according to the prior art. According to the invention, it is not necessarily necessary to increase the temperature of the curable mass during to pay attention to irradiation with energy radiation.

Fig. 1 shows in cross section an example of a photographic recording material produced according to the example.

The photographic recording material according to the invention has at least one image-bearing layer and a protective coating layer cured by means of active energy on a layer support.

Such a photographic recording material is obtained by forming the active energy radiation-cured layer-like protective coating on at least one image-bearing layer on a layer support (hereinafter referred to as "image part", for example a photographic recording material with an image formed thereon by exposure and development, and the like).

The protective layer formed on an image part should preferably consist of the layer furthest from the substrate. On the side even further from the substrate than the protective layer, i.e. on the outside, a cover layer, a further protective layer or a laminated layer and the like can also be provided.

According to the invention, the layer-like protective coating of the photographic recording material is obtained by irradiation with active energy radiation to cure an active energy-curable mass with certain prepolymers with at least two epoxy groups in the molecule and a polymerization initiator activated by active energy radiation. However, the water content in the image-bearing layer before the energy radiation-curable mass is applied must be 20.0% by weight or less.

Resin masses that can be cured by various types of energy radiation (e.g. UV radiation and other types of radiation) are suitable as masses that can be cured by active energy radiation to form a layer-like protective coating that can be used according to the invention. Special masses will be described in more detail later.

According to the invention, the temperature of the hardenable mass can be arbitrary during irradiation with active energy radiation. For example, one can work at normal temperatures of 18ºC, 20ºC or 23ºC or set the temperature to a value of 30 to 100ºC.

According to the invention, the water content of the image-bearing layer on said image part before application of the active energy ray-curable resin composition is 20.0% by weight or less.

According to the invention, the water content is determined according to the following equation. In this equation, the weight of the image-bearing layer of a test specimen is designated as Ww and the weight of the image-bearing layer after the water content has been removed from the image-bearing layer by drying the test specimen is designated as Wd:

Water content (wt%) = {(Ww - Wd)/Ww} × 100.

The "test specimens" are parts of the image before the application of the mass that can be cured by active energy radiation and after the water content has been adjusted.

Specifically, the water content can be determined using a standard infrared water meter (e.g. a digital table water meter IRAN 110 from CHINO Seisakusho) and the like.

There are various ways to adjust the water content to this range. Each of these options can be at will. In particular, there are a wide variety of ways of controlling or adjusting the water content in the practice of the present invention. Easily feasible measures for controlling the water content are to subject the image-bearing layer to appropriate temperature and humidity conditions. This takes advantage of the facts known in the relevant art that the water content in the layer varies greatly according to the properties of the binder contained in the image-bearing layer and that, furthermore, the water content, which also undergoes changes depending on the binders and binder amounts contained in the image-bearing layer, varies greatly in particular according to the temperature and humidity conditions to which the image-bearing layer is exposed. More specifically, the water content can be controlled by methods in which the relative humidity is changed by changing the dew point or the temperature of the air stream applied, or the water content is changed by heating the image-bearing layer once.

When a UV-curable composition is used as the active energy ray-curable composition according to the invention, sunlight, a low-pressure mercury lamp, a high-pressure mercury lamp, an ultra-high-pressure mercury lamp, a carbon arc lamp, metal halide lamps, xenon lamps and the like can be used as light sources for irradiation with light in the UV range (hereinafter referred to only as "UV radiation").

The atmosphere during irradiation with UV radiation can consist either of air or, on the other hand, of an inert gas such as gaseous nitrogen, carbon dioxide and the like.

The duration of UV radiation irradiation of the UV-curable composition according to the invention depends further on the UV light source used for irradiation in the UV light range. Light source of the type described. It is expediently 0.5 s to 5 min, preferably 3 s to 2 min.

Usually, a larger light source with higher radiation intensity must be used for a shorter irradiation time. A light source with lower radiation intensity is suitable for a longer irradiation time. The latter, however, is a disadvantage for the production stages, since the curing takes longer. According to the invention, the tasks set can be solved in an advantageous manner by irradiation for 3 s to 2 min using a lamp that delivers UV radiation of 200 W or less.

In addition to the resin mass curable by UV radiation mentioned above, resin masses curable by other active energy radiations are also suitable - taking into account the properties of the respective active energy radiation and the masses.

Such resin compositions can be applied as a liquid resin base material to a substrate, for example the outermost layer (for example the image-bearing layer) on a tape-shaped substrate. The application of the liquid resin base material to the layer surface can be carried out in a conventional manner, for example by means of a double-roll coating device, a gravure offset coating device, a slot coating device, an air knife coating device, a wire rail coating device, a slide hopper, by spray coating and the like. With the help of these measures, for example, the surface of a card-shaped image part can be coated in a simple manner. The layer thickness can be arbitrary, but it is expediently 0.1 to 30 µm, preferably 1 to 15 µm.

The prepolymer with at least two epoxy groups in the molecule, which is the elementary component in the inventive The composition to be used as an energy-ray curable composition consists of an epoxy resin which is converted into a polymer or crosslinked into a polymer by irradiation with energy rays in the presence of a polymerization initiator activated by the active energy rays. The resin includes known aromatic epoxy resins, alicyclic resins and aliphatic epoxy resins which are used in combination.

Aromatic epoxy resins preferred in the present case are polyglycidyl ethers of polyhydric phenols or alkylene oxide adducts thereof including glycidyl ethers and epoxy novolac resins prepared by reaction between bisphenols or alkylene oxide adducts and epichlorohydrin.

Preferred alicyclic epoxy resins are, for example, polyglycidyl ethers of polyhydric alcohols having at least two alicyclic rings or cyclohexane oxide- or cyclopentene oxide-containing compounds obtained by epoxidation of compounds containing a cyclohexene or cyclopentene ring with a suitable oxidizing agent, such as hydrogen peroxide, peracid and the like.

Representative examples of alicyclic epoxy resins are hydrogenated bisphenol A diglycidyl ether, 3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexanecarboxylate, 2-(3,4-epoxycyclohexyl-5,5-spiro-3,4-epoxy)cyclohexanemethadioxane, bis(3,4-epoxycyclohexylmethyl)adipate, vinylcyclohexane dioxide, bis(3,4-epoxy-6-methylcyclohexylmethyl)adipate, 3,4-epoxy-6-methylcyclohexyl-3,4-epoxy-6-methylcyclohexanecarboxylate, methylenebis(3,4-epoxycyclohexane)dicyclopentadienediepoxide, di(3,4-epoxycyclohexylmethyl) ether of Ethylene glycol, ethylene bis(3,4-epoxycyclohexanecarboxylate), dicyclopentadiene epoxide and the like.

Furthermore, preferred aliphatic epoxy resins are polyglycidyl ethers of aliphatic polyhydric alcohols or their alkylene oxide adducts and homopolymers and copolymers of polyglycidyl esters, Glycidyl acrylates or glycidyl methacrylates of aliphatic long-chain polybasic acids. Representative examples thereof are glycidyl ether of 1,4-butanediol, diglycidyl ether of 1,6-hexanediol, triglycidyl ether of glycerin, triglycidyl ether of trimethylolpropane, polyglycidyl ether of sorbitol, diglycidyl ether of polyethylene glycol, diglycidyl ether of polypropylene glycol, polyglycidyl ether of polyether polyols obtained by adding one or two or more kinds of alkylene oxides to aliphatic polyhydric alcohols such as ethylene glycol, propylene glycol, glycerin and the like, diglycidyl esters of aliphatic long-chain dibasic acids, epoxidized polybutadiene and the like.

In addition to the prepolymer with at least two epoxy groups in the molecule, which forms the elementary component in the energy radiation-curable mass to be used according to the invention, a monoepoxide or a cationically polymerizable organic substance that is different from the epoxy resin can also be used, depending on the desired properties.

Examples of the usable monoepoxide are monoglycidyl ethers of higher fatty alcohols or monoglycidyl ethers of phenol, cresol, butylphenol or polyether alcohols obtained by adding alkylene oxides thereto, glycidyl esters of higher fatty acids, epoxidized soybean oil, butyl epoxy stearate, octyl epoxy stearate, epoxidized linseed oil and the like.

Examples of cationically polymerizable organic substances are oxetane compounds such as trimethylene oxide, 3,3-dimethyloxetane, 3,3-dichloromethyloxetane and the like; oxorane compounds such as tetrahydrofuran and 2,3-dimethyltetrahydrofuran; cyclic acetal compounds such as trioxane, 1,3-dioxorane and 1,3,6-trioxanecyclooctane; cyclic lactone compounds such as β-propiolactone and ε-caprolactone; thiirane compounds such as ethylene sulfide, 1,2-propylene sulfide and thioepichlorohydrin; Thiethane compounds such as 1,3-propylene sulfide and 3,3-dimethylethane; vinyl ether compounds such as ethylene glycol divinyl ether, polyalkylene glycol divinyl ether, alkyl vinyl ether and 3,4-dihydropyran-2-methyl(3,4-dihydropyran-2-carboxylate); spiro-ortho-ester compounds obtained by reacting epoxy compounds with lactone; ethylenically unsaturated compounds such as vinylcyclohexane, isobutylene and polybutadiene; and derivatives of the above compounds.

Suitable polymerization initiators that can be activated by active energy radiation are compounds that release a substance that initiates cationic polymerization by irradiation with energy radiation. A group of complex salts that are onium salts that release a Lewis acid with the ability to initiate polymerization when exposed to radiation is particularly preferred.

Representative examples of such compounds can be given by the formula:

[R¹aR²bR³cR&sup4;dZ] +m [MXn+m]-m

play.

[Herein, the cation is onium; Z = S, Se, Te, P, As, Sb, Bi, O, a halogen (e.g., I, Br, Cl) or N=N; R¹, R², R³ and R⁴ are organic groups which may be the same or different; a, b, c and d are each an integer from 0 to 3, a + b + c + d corresponds to the valence of Z; M = B, P, As, Sb, Fe, Sn, Bi, Al, Ca, In, Ti, Zn, Sc, V, Cr, Mn or Co; X is a halogen; m corresponds to the net charges of the halide complex ion; and n corresponds to the electric charge number of M.

Specific examples of the anion MXn+m in the given formula are tetrafluoroborate (BF₄⁻), hexafluorophosphate (PF₆⁻), hexafluoroantimonate (SbF₆⁻), hexafluoroarsenate (AsF₆⁻), hexachloroantimonate (SBCl₆⁻) and the like.

Anions of the formula MXn(OH)⊃min; can also be used.

Of these onium salts, aromatic onium salts can be used particularly effectively as cationic polymerization initiators. These include, for example, the aromatic halonium salts disclosed in Japanese Unexamined Patent Publication Nos. 151996/1975 and 158680/1975 and the like; the aromatic onium salts of Group VIa disclosed in Japanese Unexamined Patent Publication Nos. 151997/1975, 30899/1977, 55420/1981 and 125105/1980 and the like; the aromatic onium salts of Group Va disclosed in Japanese Unexamined Patent Publication No. 158698/1975; the oxosulfoxonium salts disclosed in Japanese Unexamined Patent Publication Nos. 8428/1981, 149402/1981, 192429/1982 and the like; the aromatic diazonium salts disclosed in Japanese Patent Publication No. 17040/1974 and the like; the thiopyrilium salts disclosed in U.S. Patent No. 4,139,655 and the like; etc.. Also included are aluminum complex/photopolymerizable silicon compound type initiators and the like.

Together with the cationic polymerization initiators, photosensitizers such as benzophenone, benzoin isopropyl ether, thioxanthone and the like can also be used.

In the active energy radiation-curable composition usable according to the invention, the polymerization initiator is generally suitably contained in an amount of 0.1 to 15, preferably 1 to 10 parts by weight per 100 parts by weight of the energy radiation-curable prepolymer.

In the active energy radiation-curable composition to be used according to the invention, in addition to the prepolymer described, suitable amounts of organic substances polymerizable by radical chain polymerization, heat-sensitive polymerization initiators, colorants, such as Pigments, dyes and the like, a wide variety of resin additives such as defoamers, thickeners, leveling agents, flame retardants, UV absorbers, antioxidants and the like, fillers, resins for modification and the like. Examples of organic substances polymerizable by radical chain polymerization are acrylate resins, e.g. epoxy acrylate, urethane acrylate, polyester acrylate, polyether acrylate and the like. Suitable heat-sensitive polymerization initiators are aliphatic onium salts, such as those known from unexamined Japanese patent publications Nos. 49613/1982 and 37004/1983.

According to the invention, it is not at all necessary to provide a further adhesive layer or to subject the image-bearing layer to a surface treatment in order to improve the adhesion between the layer furthest away from the layer carrier, for example the image-bearing layer, and the protective layer that can be cured by active energy radiation, e.g. UV radiation.

Both opaque and transparent supports are suitable as a layer support or base for the recording material according to the invention. Examples of suitable supports are paper, paper laminated with polyethylene, photographic layer supports obtained by applying an electron-curable mass containing a white pigment to the surface of paper and then curing (the coating) with an electron beam, synthetic resin sheets and the like.

For reasons of image hardenability, a reflective support with an oxygen permeability (of the support) of 2.0 ml/m² h atm or less, preferably 1.0 ml/m² h atm, should be used. For reasons of adequate hardness and handleability, homopolymers and copolymers, e.g. polyester, vinyl alcohol, vinyl chloride, fluorinated vinyl, vinyl acetate and the like, homopolymers and copolymers such as cellulose acetate, acrylonitrile, alkyl acrylate, alkyl methacrylate, methacrylonitrile, alkyl vinyl esters, alkyl vinyl ethers, polyamide and the like, and films laminated with these polymers.

Of these films, those made of polyesters, film laminates of polyester and polyethylene and laminated paper are preferred. Furthermore, a polyester film preferably has the same oxygen permeability under high humidity conditions and under dry conditions, since the oxygen permeability is not dependent on humidity.

To make the substrate reflective, it can contain a white pigment or a hydrophilic colloid layer containing a white pigment can be applied.

Inorganic and/or organic pigments are suitable as white pigments, preferably inorganic white pigments. Examples of such pigments are sulfates of alkali metals*, such as barium sulfate and the like, carbonates of alkaline metals**, such as calcium carbonate and the like, silicas, e.g. finely powdered silica and synthetic silicates, calcium silicate, aluminum oxide, aluminum oxide hydrate, titanium oxide, zinc oxide, talc, clay and the like. The white pigment preferably consists of barium sulfate, calcium carbonate, titanium oxide, in particular barium sulfate.

The content of said opacifying pigment depends on the matrix-forming resin into which it is mixed, the film-forming conditions, the properties and the particle size of the mixed pigment. Preferably, it is 3 to 30% by weight.

* Footnote: probably alkaline earth metals

** Footnote: probably alkaline earth metals In order to prevent the card from being forged and to improve the distinguishability when the photographic recording material of the present invention is used as a card for identification purposes and the like, the opaque resin layer surface may be embossed and colored in the same manner as a transparent resin layer. Furthermore, multiple layers may also be provided.

A magnetic recording layer can also be included on the card.

Fig. 1 shows an example of a particularly suitable support structure for an identification card. In the figure, 11 denotes a white polyethylene terephthalate sheet; 12 a white adhesive polyethylene; 13 a white polyethylene terephthalate film and 14 a polypropylene art paper. Together, these components form the layer support. In a still more preferred embodiment, it is recommended to use Yupo (trade name of Oji Yuka Synthetic Paper), ie an art paper with pores, as the polypropylene art paper 14. In Fig. 1, 3 denotes a photographic emulsion layer which becomes the image-bearing layer and 4 denotes a writable layer. In the example shown in the figure, the polypropylene art paper 14 has a thickness of 80 µm. On one side of the same, a clay-containing writing layer 4 is provided as the writable layer 4 to improve writable and printable properties. In the manufacture of the support shown in the drawing, polyethylene containing 8% titanium oxide is extruded onto art paper 14 (Yupo) to form a white polyethylene 12 which acts as an adhesive. A white polyethylene terephthalate film 11 of 175 µm with a permeability density of 1.35 is adhered using this adhesive. A pattern 2 is printed on the surface opposite to the surface to which the white polyethylene terephthalate film 11 is adhered. Furthermore, a white polyethylene terephthalate film 13 of 175 µm with a permeability density of 1.35 is subjected to an adhesion treatment. of 1.35 with the aid of a dissolved polyethylene 12 extruded between them with 8% *. The layers 13 to 14 in the figure form the layer carrier according to the invention or the base 1 according to the invention.

By editing the writable layer 4, additional information can be printed.

As already stated, a preferred embodiment of the photographic recording material according to the invention consists of an identification card. The card in question can be produced by forming the protective layer according to the invention on the image part with the desired information as an image. Such an identification card is hard enough to withstand a certain physical pressure from the outside. It should preferably not be damaged by bending and the like during carrying. In particular (in this connection) a cloudy or opaque resin layer with the desired hardness is used.

In the photographic recording material of the present invention, the image part having a photographic image layer can be formed by forming an image using any desired photosensitive photographic recording material. For example, it can be formed by applying given processing steps to black-and-white or color photographic recording materials of various diffusion transfer types, diazo photosensitive recording materials, electrophotographic recording materials and the like.

* Footnote: probably titanium oxide

In the photographic recording material according to the invention, the photographic image layer should preferably consist of a layer with a hydrophilic polymer compound, which forms the layer-like protective coating with the active energy radiation-curable composition according to the invention on the photographic image layer containing the hydrophilic polymer compound.

According to the invention, suitable hydrophilic polymeric compounds in the image-bearing photographic image layer are gelatin, gelatin derivatives, graft polymers of gelatin with other polymers, other proteins, sugar derivatives and cellulose derivatives as well as synthetic hydrophilic polymeric substances such as homo- or copolymers. When using at least gelatin, the effects aimed for according to the invention are clearly evident.

Suitable gelatins include lime-treated gelatin or otherwise acid-treated gelatin or oxygen-treated gelatin (cf. "Bull. Soc. Sci. Phot. Japan", No. 16, p. 30 (1966)). Gelatin hydrolysates or enzyme degradation products of gelatin are also suitable. Suitable gelatin derivatives include a wide variety of gelatin derivatives produced using acid halides, acid anhydrides, isocyanates, bromoacetic acid, alkanesultones, vinylsulfonamides, maleimide compounds, polyalkylene oxides, epoxy compounds and the like. Specific examples of this can be found in US Patents 2,614,928, 3,132,945, 3,186,846 and 3,312,553, in GB Patents 861,414, 1,033,189 and 1,005,784 and in Japanese Patent Publication No. 26845/1967.

Albumin, casein and the like are suitable as proteins or alternative hydrophilic polymeric compounds as a replacement for or for use together with gelatin. Hydroxyethylcellulose, carboxymethylcellulose, sulfuric acid esters of cellulose and the like are suitable as cellulose derivatives. Sodium alginate and starch derivatives are preferably used as sugar derivatives.

Graft polymers of gelatin with other polymers may also be used. Such polymers are homo- or copolymers of vinyl monomers such as acrylic acid, methacrylic acid, derivatives thereof such as esters, amides and the like, acrylonitrile, styrene and the like; copolymers grafted onto gelatin may also be used. Particularly suitable are polymers which are somewhat compatible with gelatin, such as graft polymers with polymers of acrylic acid, acrylamide, methacrylamide, hydroxyalkyl methacrylate and the like. Examples of these can be found in U.S. Patent Nos. 2,763,625, 2,831,767, 2,956,884 and the like.

Instead of or in combination with gelatin, synthetic hydrophilic polymeric substances can be used. Representative examples of the synthetic hydrophilic polymeric substances are homo- or copolymers such as polyvinyl alcohol, polyvinyl alcohol partial acetal, poly-N-vinylpyrrolidone, polyacrylic acid, polymethacrylic acid, polyacrylamide, polyvinylimidazole, polyvinylpyrazole and the like (see, for example, German Laid-Open Application DOS 2,312,708, US Pat. Nos. 3,620,751 and 3,879,205 and Japanese Patent Publication No. 7561/1968).

If gelatin is used as the hydrophilic polymer compound, there are no particular limits on the gel strength of the gelatin. However, a gel strength of 250 g or higher is preferred (measured value according to the Baggy method).

The photographic image layer forming the photographic recording material according to the invention or, if desired, other hydrophilic colloid layers (additionally) formed can be hardened with the aid of one or two or more types of film hardeners to crosslink the binder (or protective colloid) molecules and increase the film strength. The film hardeners can be added in such amounts that the film is hardened to such an extent that no film hardener is required in the treatment liquid. However, it is also possible to Add the film hardener to the treatment liquid.

Furthermore, plasticizers can be added to the photographic image layer or other hydrophilic colloid layers to improve their flexibility.

The photographic image layer can be produced by applying a light-sensitive material and the like or an image-receiving layer to the described layer support, e.g. waterproof baryta paper, a white cloudy or opaque resin film, a layer support provided on the back with a black/white light-shielding layer or a layer support in the form of a transparent resin film and the like and treating it in a predetermined manner.

A positive light-sensitive silver halide recording material is suitable as an image-forming layer of the photographic recording material according to the invention. In this case, the layer support can be either opaque or transparent.

When carrying out the present invention, such a direct positive image-forming silver halide emulsion is used as an emulsion for the light-sensitive material forming the image-bearing layer, an internal latent image type silver halide emulsion may be used. In this case, the emulsions, additives, color-forming couplers, fogging treatment and development treatment and the like disclosed in Japanese Patent Publication No. 229133/1987, page 37, line 15, to page 62, line 1, may be used.

Examples

The present invention will be described in detail below, but it is not limited to these embodiments.

As previously explained in connection with Fig. 1, 9 layers from the red-sensitive emulsion layer to the protective layer (see below) are applied and dried by simultaneous application to a support comprising two surface-treated polyester layers 11 and 13 of 175 µm and glued to the back with an 80 µm thick polypropylene art paper 14 with a writable coating, in order to produce a color copy specimen.

Red-sensitive emulsion layer (first layer)

Into a 2.0% solution of inactive gelatin at 50°C, solutions A and B of the following composition were simultaneously injected within 3 minutes with stirring. 10 minutes later, solution C of the following composition was injected within 3 minutes. After aging for 40 minutes, excess salts were removed by the precipitation/water wash method. Thereafter, solutions D and E were added to prepare a silver chlorobromide containing 95 mol% AgCl and 5 mol% AgBr for lamination to the back. Excess water-soluble salts were again removed by the precipitation/water wash method. Finally, a small amount of gelatin was added to disperse in the mixture.

Solution A:

Pure water 500 ml

NaCl 40 g (137 mol%)

KBR 8.9 g (15 mol%)

KI 0.4 g (0.5 mol%)

Solution B:

Pure water 660 ml

AgNO3 85 g

Solution C:

Pure water 300 ml

KBr 50.6 g (85 mol%)

Solution D:

Pure water 1500 ml

NaCl 20 g (114 mol%)

KBr 1.8 g (5 mol%)

Solution E:

Pure water 500 ml

AgNO2 51 g (0.3 mol%)

Then, a sensitizing dye (D-1), a sensitizing dye (D-4), a liquid protective dispersion with 2,5-dioctylhydroquinone and a cyan coupler (CC-1) in dibutyl phthalate, 4-hydroxy-6-methyl-1,3,3a,7-tetrazaindene, 1-phenyl-5-mercaptotetrazole, gelatin and a coating aid (S-1) were added to the silver halide emulsion in a suitable manner. The silver was applied at a rate of 0.4 g/m².

First intermediate layer (second layer)

A gelatin liquid containing 2,5-dioctylhydroquinone and a UV absorbing agent (Tinuvin 328 from Ciba-Geigy) in the form of a dispersion in dioctyl phthalate with a coating aid (S-1) was prepared and applied with a Tinuvin 328 application rate of 0.15 g/m².

Green-sensitive emulsion layer (third layer)

Silver halide grains were prepared in a similar manner to the preparation of the red-sensitive emulsion. To these were added in an appropriate manner a sensitizing dye (D-2), a liquid protective dispersion containing 2,5-dioctylhydroquinone and a magenta coupler (MC-1) in dibutyl phthalate, 4-hydroxy-6-methyl-1,3,3a,7-tetrazaindene, 1-phenyl-5-mercaptotetrazole, gelatin and a coating aid (S-2). was carried out up to a silver application weight of 0.4 g/m².

Second intermediate layer (fourth layer)

The production was carried out using a similar recipe as for the production of the first intermediate layer, but the Tinuvin 328 application quantity was 0.2 g/m².

Yellow filter layer (fifth layer)

A 2,5-dioctylhydroquinone liquid was dispersed in yellow colloidal silver and dioctyl phthalate prepared by oxidation using an alkaline weak reducing agent (after neutralization, the weak reducing agent was removed by the noodle water washing method), to which (immediately before application) a coating aid (S-2) and a film thickener (H-1) were added. The mixture was applied to a silver coverage of 0.15 g/m².

Third intermediate layer (sixth layer)

The production was carried out using the same recipe as the production of the first intermediate layer, but the Tinuvin 328 application quantity was 0.15 g/m².

Blue-sensitive layer (seventh layer)

Solutions A' and B' of the following composition were injected simultaneously over 15 minutes with stirring into a 1.5% solution of inactive gelatin at 60ºC. 15 minutes later, solution C' of the following composition was injected over 2 minutes. After a further minute, hypo was added in an amount corresponding to 3 mg/Ag. The whole was then allowed to age for 40 minutes. When the composition was analyzed by sampling, the product obtained was found to be silver chlorobromide with 4 mol% AgCl, 96 mol% AgBr and 2 mol% AgI.

After removing excess salts by the precipitation/water wash process, solutions D' and E' of the composition given below were added to provide a surface layer containing 97 mol% AgCl and 3 mol% AgBr. Subsequently, excess salts were again removed by the precipitation/water wash process. Finally, gelatin was added for dispersion.

Solution A':

Pure water 1000 ml

NaCl 76g

KBr 17 g

Hexachloroiridium (III) acid salt 2 x 10⊃min;⊃5; g

Solution B':

Pure water 1000 ml

AgNO3 169.9 g

Solution C':

Pure water 800 ml

KBr103g

AI 3.3 g

Solution D':

Pure water 500 ml

AgNO2 51 g

Solution E':

Pure water 500 ml

NaCl 25.8g

KBr 1.1 g

Using the silver halide emulsion together with a liquid containing a sensitizing dye (D-3) and a yellow coupler (YC-1) in the form of a dispersion in dioctyl phthalate and a liquid containing 2-mercaptobenzothiazole, 4-hydroxy-6-methyl-1,3,3a,7-tetrazaindene, gelatin, a coating aid (S-3) and a film hardener (H-1) (added immediately before coating), the coating was carried out to a silver coating weight of 0.5 g/m².

Fourth intermediate layer (eighth layer)

The preparation was carried out using the same recipe as the preparation of the first intermediate layer, but the application was carried out up to a Tinuvin 328 application rate of 0.3 g/m². A film hardener (H-1) was added immediately before application.

Protective layer (ninth layer)

Using a gelatin solution containing non-crystalline silicon dioxide with an average grain size of 3 µm, a coating aid (5-3) and a film hardener (H-1) (added immediately before application), the coating was carried out up to a gelatin application rate of 1.0 g/m². Cyan coupler (CC-1) Purple coupler (MC-1) Yellow coupler (YC-1) Sensitizing dye (D-1) Sensitizing dye (D-2)

Sensitizing dye (D-3) Sensitizing dye (D-4) Coating aids (S-1) Coating aids (S-2) Coating aids (S-3)

H-1: 1,3,5-Triglycidylisocyanurate

The following are the specific photographic processing conditions for this example.

Treatment stages (treatment temperature and treatment duration)

[1] Immersion (colour developer bath) 38ºC 8 s

[2] Veiling exposure 10 s at 1 lux

[3] Colour development 38ºC 2 min

[4] Bleaching and fixing 35ºC 60 s

[5] Stabilization treatment 25 - 30ºC, 1 min 30 s

[6] Drying 75 - 80ºC, 1 min

Composition of the treatment baths: (Color developer solution)

Benzyl alcohol 10 ml

Ethylene glycol 15 ml

Potassium sulphite 2.0 g

Potassium bromide 1.5 g

Sodium chloride 0.2 g

Potassium carbonate 30.0 g

Hydroxylamine sulfate 3.0 g

Polyphosphoric acid (TPPS) 2.5 g

3-Methyl-4-amino-N-ethyl- N-(β-methanesulfonamidoethyl)aniline sulfate 5.5 g

Fluorescent brightener (4,4'-diaminostilbenesulfonic acid derivative) 1.0 g

Potassium hydroxide 2.0 g (filled up to 1 l with water, the pH value was adjusted to 10.20)

(Bleach/Fixing Bath)

Iron (III) ammonium ethylenediaminetetraacetate dihydrate 60 g

Ethylenediaminetetraacetic acid 3 g

Ammonium thiosulfate (70% solution) 100 ml

Ammonium sulphite (40% solution) 27.5 ml

(the pH was adjusted to 7.1 with potassium carbonate or glacial acetic acid, after which the solution was filled to a total of 1 l)

(Stabilizing bath)

5-Chloro-2-methyl-4-isothiazolin-3-one 1.0 g

Ethylene glycol 10 g

1-Hydroxyethylidene-1,1'-diphosphonic acid 2.5 g

Bismuth chloride 0.2 g

Magnesium chloride 0.1 g

Ammonium hydroxide (28% aqueous solution) 2.0 g

Sodium nitrilotriacetate 1.0 g

(filled up to 1 l with water, the pH value was adjusted to 7.0 with ammonium hydroxide or sulphuric acid)

The stabilization treatment was carried out in a countercurrent system consisting of two tanks.

The image-bearing recording materials subjected to the development treatment described were controlled to be humidified to the water contents indicated in Table 1 by blowing air of different humidity contents against them. More specifically, the sample, which had previously been conditioned for one day and one night at a temperature of 23ºC and a relative humidity of 80%, was exposed to a stream of air at 23ºC with a relative humidity of 0%, 10%, 20%, 30%, 40%, 55% or 70% for 5 minutes to humidify it to water contents of 5.0, 8.0, 13.0, 15.0, 17.0, 19.0 or 25.0 wt.%, respectively. Afterwards, the energy radiation-curable masses or comparison masses according to Table 1 were immediately applied to produce test specimens 1 to 14.

In the examples, the water content was determined as follows: Using a standard infrared water meter, for example a digital table water meter IRA H110 by CHINO Seisakusho, a calibration curve was first prepared and then the water content of the image-bearing layer was determined before applying a radiation energy-curable resin. The calibration curve can be prepared by the method described below.

A substrate with an image-bearing layer thereon and a substrate from which the image-bearing layer had been peeled off were humidified with air of different humidity levels (humidity conditions: 0, 20, 55 and 80% relative humidity, respectively) for two days under controlled conditions. Each sample was placed in an infrared water meter and the measured value was read. On the other hand, the weights of the samples were determined. After drying at 120ºC for three hours, the sample weights were determined again. From the difference in weight before and after drying, the water content per unit area is determined. The value obtained by subtracting the water content of only the substrate from the water content of the substrate with the image-bearing layer thereon is defined as the water content of the image-bearing layer. The water content is determined from the equation given above. By assigning the water content to the value determined using the infrared water meter, a calibration curve is created.

The color copy specimen, which is the image-bearing recording material described above, was coated with the mass of the following composition. After subsequent hardening, it was provided with a protective layer.

The application and curing of the respective mass was carried out by applying the coating masses (1) to (6) according to the present invention (see later) or the acrylic mass as a comparative example up to an application quantity of 10 g/m² and curing the respective mass by irradiating with UV radiation using a high-pressure mercury lamp of 60 W/cm² from a distance of 10 cm for 4 s to harden the applied mass. The temperature immediately before irradiation with UV radiation was set to 20ºC.

(Comparison mass) Acrylic resin mass:

Pentaerythritol triacrylate 21 parts

Pentaerythritol tetraacrylate 9 parts

Urethane acrylate 70 parts

(Unidic 17-849, manufactured by Dainippon Ink Kagaku Kogyo)

Benzoin ethyl ether 5 parts

(UV-curable mass) Epoxy resin mass (1):

Bisphenol A diglycidyl ether 15 parts

3,4-Epoxycyclohexylmethyl-3,4-epoxycyclohexanecarboxylate 65 parts

1,4-Butanediol diglycidyl ether 20 parts

Fluorine type wetting agent 1 part

Aromatic sulfonium salt type UV initiator 5 parts

Epoxy type resin mass (2):

Bisphenol A diglycidyl ether of the side chain type 15 parts

3, 4-Epoxycyclohexylmethyl-3, 4-epoxycyclohexanecarboxylate 70 parts

Trimethylolpropane triglycidyl ether 15 parts

Fluorine type wetting agent 2 parts

Aromatic sulfonium salt type UV initiator 6 parts

Epoxy type resin mass (3):

Bisphenol A glycidyl ether of the side chain type 10 parts

3,4-Epoxycyclohexylmethyl-3,4-epoxycyclohexanecarboxylate 65 parts

Sorbitol polyglycidyl ether 25 parts

Fluorine type wetting agent 1 part

Aromatic sulfonium salt type UV initiator 6 parts

Mass of epoxy type (4):

Bisphenol-F-diglycidyl ether 15 parts

Bis (3,4-epoxycyclohexylmethyl) adipate 20 parts

3,4-Epoxycyclohexylmethyl-3,4-epoxycyclohexanecarboxylate 50 parts

Pentaerythritol polyglycidyl ether 15 parts

Silicone type wetting agent 2 parts

Aromatic sulfonium salt type UV initiator 5 parts

Epoxy type mass (5):

Hydrogenated bisphenol A diglycidyl ether 30 parts

3,4-Epoxycyclohexylmethyl-3,4-epoxycyclohexanecarboxyl at 40 parts

Bis (3,4-epoxycyclohexylmethyl) adipate 15 parts

Trimethylolpropane triglycidyl ether 15 parts

Silicone type wetting agent 3 parts

Aromatic sulfonium salt type UV initiator 5 parts

Epoxy type mass (6):

Polyglycidyl ether of the phenol novolak type 10 parts

3,4-Epoxycyclohexylmethyl-3,4-epoxycyclohexanecarboxylate 60 parts

Polyglycerol glycidyl ether 25 parts

Glycidyl ether of a higher fatty alcohol 5 parts

Fluorine type wetting agent 1 part

Aromatic iodonium salt type UV initiator 4 parts

(Evaluation of the candidates)

The test specimens produced in the manner described were evaluated as follows:

1. Adhesion to the photographic image layer:

Liabilities (1) to (4) were determined as follows:

(1) Cellotape (manufactured by Nichiban) was firmly adhered to the surface of the cured protective layer and then quickly peeled off from the surface. The peeling state was then evaluated.

(2) The protective layer was damaged at a 90º angle using a cutting device. The adhesion to the photographic image layer was then determined at this point in accordance with (1).

(3) A test specimen with a hardened layer-like coating was immersed in tap water at 20ºC for one day and one night. The adhesion to the photographic image layer was then determined at the relevant location in accordance with (1).

(4) A test specimen with a hardened layer-like coating was immersed in tap water at 20ºC for one day and one night. The adhesion to the photographic image layer was then determined at the relevant location in accordance with (2).

The results of the adhesion test are given in Table 1 as the percentage of remaining surface of the cello tape that remained adhered. If this value is 80% or more, the adhesion is considered sufficient for practical use.

As can be seen from Table 1, all test specimens according to the invention showed excellent adhesion properties in the adhesion tests (1) to (4). Results. Under the drastic conditions of damage with a cutting device (2), a residual area of 90% or more was determined. In the water resistance tests (4) and (3) values of around 100% or at worst 90% were also determined. This shows that the adhesion is extremely good even under unfavorable conditions.

Further, on a support in the form of a laminate of polyethylene on a photographic original paper to prepare an image recording material, the first to ninth layers described above were separately coated. However, as a film hardener for the protective layer (i.e., the ninth layer), the following compound was used instead of the hardener (H-1):

(This compound corresponds to Compound No. 41 of Japanese Unexamined Patent Publication No. 229133/1987.)

The resulting image recording material was subjected to a photographic treatment in the manner described, coated with the epoxy type mass (1) and cured by irradiation with UV radiation. Curing was carried out here at 23°C (normal temperature) without heating.

An assessment of the photographic recording material obtained showed that the adhesion was similar to that of a test specimen according to the invention, but that the sensitivity was significantly lower than that of the test specimen according to the invention. Table 1 Test specimen Water content of the image-bearing layer in % by weight Radiation-curable mass or reference mass Adhesion mass of epoxy type Acrylic resin mass

As previously stated, the present invention provides a photographic recording material having a protective layer formed thereon by curing with active energy radiation, having good adhesion of the image-forming layer and the like, and having good water resistance. Furthermore, a method is provided for the simple and inexpensive production of such a photographic recording material by irradiation with low-energy active energy radiation.

Claims (13)

1. Photographic element comprising a support, at least one image-bearing layer thereon and a protective layer on the image-bearing layer, wherein this protective layer is obtained by curing an epoxy composition curable by high-energy radiation and a polymerization initiator activatable by the high-energy radiation by irradiation with high-energy radiation, characterized in that the epoxy composition consists of a prepolymer having at least two epoxy groups and with a combination of an aromatic, an alicyclic and an aliphatic epoxy resin and that the image-bearing layer has a water content of 20.0 wt.% or less. 2. Photographic element according to claim 1, characterized in that the protective layer is the layer furthest from the support. 3. A photographic element according to claim 1, characterized in that the epoxy composition is an ultraviolet curable composition. 4. Photographic element according to claim 1, characterized in that the protective layer is cast to a thickness of 0.1 µm to 30 µm. 5. Photographic element according to claim 4, characterized in that the protective layer is cast to a thickness of 1 µm to 15 µm. 6. Photographic element according to claim 1, characterized in that the prepolymer is an epoxy resin which can be converted into a polymer by irradiation with energetic radiation in the presence of the polymerization initiator converted or networked. 7. Photographic element according to one of claims 1 to 6, characterized in that the polymerization initiator is a compound which can release a substance capable of initiating a cationic polymerization by irradiation with high-energy radiation. 8. Photographic element according to claim 7, characterized in that the polymerization initiator is selected from a group of complex salts which are onium salts which, upon irradiation, release a Lewis acid with the ability to initiate polymerization. 9. Photographic element according to claim 8, characterized in that the polymerization initiator has one of the formula: [R¹aR²bR³cR&sup4;dZ] +m [MXn+m]-m is a compound in which the cation is an onium, Z represents at least one element or group selected from S, Se, Te, Pl, As, Sb, Bi, O, halogen or N=N, R¹, R², R³ and R⁴ represent organic groups which may be the same or different, a, b, c and d each represent an integer from 0 to 3, and a + b + c + d are equal to the valence of Z, M represents B, P, As, Sb, Fe, Sn, Bi, Al, Ca, In, Ti, Zn, Sc, V, Cr, Mn or Co, X represents halogen, m is the net charge of the halide complex ion and n represents the electrical charge number of M. 10. Photographic element according to claim 8, characterized in that the anion MXn+m in the formula is at least one of tetrafluoroborate (BF₄⁻), hexafluorophosphate (PF₆⁻), hexafluoroantimonate (SbF₆⁻), rexafluoroarsenate (AsF₆⁻), hexachloroantimonate (SbCl₆⁻) and anions of the formula MXn(OH)⁻. 11. Photographic element according to one of claims 1 to 10, characterized in that the polymerization initiator is present in an amount of 0.1 to 15 parts by weight of the prepolymer, based on 100 parts by weight Prepolymer, is present. 12. Photographic element according to claim 1, characterized in that the polymerization initiator is present in an amount of 1 to 10 parts by weight, based on 100 parts by weight of prepolymer. 13. A process for producing a photographic element comprising a support, at least one image-bearing layer thereon and a protective layer, which includes the following stages: Applying at least one layer for carrying an image on that support, Creating an image on this layer for carrying an image, Casting a high energy radiation curable epoxy composition and a polymerization initiator that can be activated by high energy radiation on the resulting image-bearing layer and Irradiation of this curable epoxy composition with high-energy radiation, characterized, that this curable epoxy composition consists of a prepolymer having at least two epoxy groups and a combination of an aromatic, an alicyclic and an aliphatic epoxy resin and that the image-bearing layer has a water content of 20.0 wt.% or less.