JP2003287849A - Silver halide photographic material - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a silver halide photographic sensitive material simultaneously improved in peeling of a back coat layer, dryability and staining property. <P>SOLUTION: In the silver halide photographic sensitive material having a back coat layer containing a filter dye disposed on a support having an electroconductive polymer layer, the back coat layer contains gelatin having ≤50 ppm concentration of calcium ions as a principal binder and also contains a carbonate. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a silver halide photographic light-sensitive material excellent in film peeling and residual color of a backing layer and drying property in a developing process, and is particularly used in the field of graphic arts. The present invention relates to a silver halide photographic light-sensitive material.

[0002]

2. Description of the Related Art In the field of graphic arts, it has been well known in recent years that a conductive polymer layer is used as an undercoat layer and a film having an antistatic property is used. Recently, with the development of digital processing of images, there is a demand for a method of forming a final plate directly by a relatively inexpensive image setter by performing a plate collecting operation on a computer without going through the conventional complicated process. Therefore, a simpler and maintenance-free image forming method has been demanded. However, in the case of a color printed matter, four color (or at least two or more) originals (plates) are created and attached using Cellotape (registered trademark) so that the colors do not shift in each plate. It is often pasted using cellophane tape as various plate making techniques. When peeling the cellophane tape after such work, if the adhesion between the conductive polymer layer (undercoat layer) and the backing layer is weak, the backing layer will be peeled off together with the cellophane tape. It had drawbacks.

As an improvement of such film peeling, use of polymer latex is disclosed in JP-A-7-261307. However, when the amount of the polymer latex used is increased, the film peeling is improved, but there is a problem that the residual color of the filter dye is deteriorated.

On the other hand, since the film output by the imagesetter is the final version, the sensitizing dye or halation, which has not been a practical problem in the past, was used.
When the residual color of the anti-irradiation dye is remarkable, it causes a problem in the next step or greatly deteriorates the value as a product, and a silver halide photographic light-sensitive material having less residual color has been strongly demanded.

Further, from the demand for shortening the time for the plate making process, there has been a strong demand in the market for shortening the processing time in recent years.
Even with rapid processing, there is a strong demand for films with excellent dryness, and sufficient curing is necessary to keep the water absorption of the hydrophilic colloid layer of the film low, including the backing layer. There is a problem that the residual color of the dye is deteriorated as the degree of curing of the layer is increased.

As an improvement of the residual color property, Japanese Patent Laid-Open No. 2000-2 has been proposed.
No. 67217 discloses the use of a vinyl sulfone type hardener. However, although the residual color of the dye is improved by using the vinyl sulfone type hardener, the above-mentioned drying property and film peeling are not improved. Further, it is well known to use a triazine type hardener as a hardener for suppressing the amount of water absorption. However, the use of the triazine hardener improves the drying property, but deteriorates the residual color of the dye, and the film peeling is not improved.

[0007]

SUMMARY OF THE INVENTION It is, therefore, an object of the present invention to provide a silver halide photographic light-sensitive material in which the peeling and residual color of the backing layer and the drying property in the development process are simultaneously improved. The present invention is to improve the drying property and film peeling which is a problem when using a vinyl sulfone type hardener, and to further enhance the effect of improving the residual color of the vinyl sulfone type hardener, It is intended to improve the residual color property and film peeling which are problems when a triazine hardener is used.

[0008]

The above object of the present invention is to provide a silver halide photographic light-sensitive material having a backing layer containing a filter dye on a support having a conductive polymer layer. Has a calcium ion concentration of 500p
Contains gelatin of pm or less as the main binder,
And basically achieved by containing carbonate.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention is described in detail below.
As the conductive polymer used in the present invention, there are ionic and nonionic polymers, but in general, nonionic polymers are often inferior to ionic polymers in their antistatic properties. Therefore, an ionic polymer is often used from the viewpoint of exhibiting antistatic performance. Ionic polymers having antistatic properties are classified into cationic ones and anionic ones. Examples of anionic polymers are polystyrene sulfonic acid and its salts, N-methylol (meth) acrylamide and styrene. A copolymer of sulfonic acid and a salt thereof, a copolymer of a (meth) acrylate derivative containing a substituted or unsubstituted amino group and styrenesulfonic acid and a salt thereof,
Polymer containing a (meth) acrylic repeating unit ester-bonded to an atomic group containing a sulfonic acid group or / and a sulfate ester group and a salt thereof, a sulfonic acid group or /
And a derivative of polyvinyl alcohol in which an atomic group containing a sulfate ester group is introduced by an ether bond or an ester bond and a salt thereof, a sulfonic acid group or / and a sulfate ester group-modified polyolefin compound, a sulfate esterified starch,
There are dextran sulfate and the like, and any of them can be used as a polymer for forming an antistatic (conductive) layer.

In the polystyrene sulfonic acid derivative of the present invention, the physical properties of the obtained coating film can be adjusted by selecting the monomers used for the copolymerization. JP 55
-84658, 61-174542 and JP-A-2-208651 disclose a polystyrene sulfonic acid derivative having a carboxyl group introduced therein, and JP-A-3-229787 discloses a polystyrene sulfonic acid having N-methylol acrylamide as a constituent unit. Derivatives, and JP-A-5-202333 describe or exemplify polystyrene sulfonic acid derivatives copolymerized with a monomer having a substituted amino group. Among them, the one having a self-crosslinking site introduced and the one having a site highly reactive with a crosslinking agent are advantageous in terms of physical properties of the film.

The conditions for using the antistatic polymer of the present invention are as follows:
The type and concentration of the antistatic polymer may be set based on the required antistatic performance (workability). The optimum use concentration depends largely on the required performance, properties, and the mixing ratio with them at the time of use, but the use concentration for the coating liquid and the coating amount at the time of drying are preferably 0.1 to 7.0% by weight and 0.02.
˜3.0 g / m ² , more preferably 0.4 to 5.0 wt% and 0.1 to 2.0 g / m ² .

As the support, any one for photographic use can be used, but a transparent support such as polyethylene terephthalate or cellulose triacetate made so as to transmit visible light by 90% or more is preferable.

The backing layer of the present invention will be described. As the binder of the backing layer of the present invention, gelatin having a calcium ion concentration of 500 ppm or less (hereinafter referred to as decalcified gelatin) is mainly used. The gelatin used in the present invention can be obtained by purification (decalcification treatment) according to a known method such as a water washing method or an ion exchange method. Calcium (Ca ++) ion concentration of gelatin generally used for photography is 1000 to 5000 pp
However, the calcium-free gelatin used in the backing layer of the present invention is used as the main binder. The backing layer of the present invention can be used in combination with other binders.
Other binders include non-purified (desalted) photographic gelatin, water-soluble polymers such as polyacrylamide, polyvinyl alcohol, polyvinylpyrrolidone, and dextran sulfate. The decalcified gelatin is used in an amount of 60% by weight or more, preferably 80% by weight or more, more preferably 95% by weight or more, based on the total amount of binder in the backing layer. Considering the drying property, etc., 1
The amount is 0 g / m ² or less, preferably 1 g / m ² to 5 g / m ² . The calcium ion concentration of the decalcified gelatin used in the present invention is preferably 300 pp.
m or less, and more preferably 100 ppm or less.

Examples of the carbonate used in the present invention include sodium carbonate, potassium carbonate, sodium bicarbonate and potassium bicarbonate. The content of these compounds in the backing layer is preferably 0.1 mmol / m ² or more and 10 mmol / m ² or more, more preferably 1 mmol / m ² or more and 5 mmol / m ² or less.

In the present invention, in the backing layer containing a filter dye, the combination of the above-mentioned decalcified gelatin and a carbonate causes the residual color property, film peeling and drying property which are the objects of the present invention. At the same time, I found improvements. In particular, it was found that the constitution of the backing layer of the present invention described above exerts a higher effect in relation to the hardener used. That is, by using in combination with a vinyl sulfone-based hardener or a triazine-based hardener, the effects (advantages) of the above-mentioned hardener can be utilized or further enhanced, while the problems (defects) of the above-mentioned hardener are simultaneously solved. It is to improve. Details will be described below.

In the present invention, the hardener for the backing layer is
It is preferable to use a vinyl sulfone type hardener. INDUSTRIAL APPLICABILITY The present invention further enhances the residual color effect of the vinyl sulfone type hardener, and improves the drying property and peeling of the film, which are the problems of the hardener. As this vinyl sulfone type hardener, Japanese Patent Publication No. 44-29
622, 47-8736, and JP-A-48-7483.
No. 2, No. 49-24435, No. 51-44164,
53-41221, U.S. Pat. No. 4,173,481,
The compounds described in No. 4,323,646 and the like can be used. Specific examples are shown below, but the present invention is not limited thereto.

[0017]

[Chemical 1]

[0018]

[Chemical 2]

[0019]

[Chemical 3]

In the present invention, the addition amount of the vinyl sulfone type hardener needs to be adjusted slightly depending on the compound, but is preferably in the range of 0.1 to 15% by weight based on the gelatin of the backing layer, It is preferably 5 to 15% by weight.
When the content is further increased in order to improve the drying property, a problem that the residual color property is deteriorated occurs.

As the hardener for the backing layer of the present invention, it is preferable to use a triazine hardener. The present invention makes use of the effect of improving the drying property of the triazine hardener,
The residual color property and film peeling, which are problems of the hardener, are improved. Specific examples are shown below, but the present invention is not limited thereto.

[0022]

[Chemical 4]

[0023]

[Chemical 5]

In the present invention, the amount of the triazine-based hardener added needs to be adjusted slightly depending on the compound, but is preferably in the range of 0.1 to 15% by weight, more preferably in the amount of gelatin in the backing layer. Is preferably 1 to 10% by weight in view of the residual color.

These hardeners may be added at any stage from the preparation of the backing coating solution to the coating. Further, the effect of the present invention is not hindered by not directly adding it to the backing coating liquid but adding it to an adjacent layer such as a backing protective layer.

The filter dyes used in the present invention are very well known. These dyes can be used to provide protection against halation and / or minimize unwanted exposure. Useful filter dyes include oxonols, cyanines, merocyanines,
Includes arylidene and the like. The filter dye used in the present invention may be diffusible or non-diffusible, but in order to avoid residual color as much as possible, it is better to be soluble during photographic processing. Diffusible dyes are preferably incorporated into photographic elements with mordants to prevent dye migration prior to photographic processing. Useful dyes are described in US Pat.
Pyrazolone oxonol dyes described in US Pat. No. 274,782, soluble diarylazo dyes described in US Pat. No. 2,956,879, US Pat. No. 3,42.
Soluble styryl and butadienyl dyes described in US Pat. Nos. 3,207 and 3,384,487, merocyanine dyes described in US Pat. No. 2,527,583, US Pat. No. 3,486,897. Issue 3,65
2,284 and 3,718,472, merocyanine and oxonol dyes, US Pat. No. 3,976,661, enaminohemioxonol dyes, and US Pat. , 723,15
No. 4, cyanomethyl sulfone-derived merocyanines, US Pat. Nos. 2,739,888, 3,253,921, 3,250,617 and 2,739,971 Thiazolidones, benzotriazoles and thiazolothiazoles described in the specification, triazoles described in US Pat. No. 3,004,896, and US Pat. No. 3,215,597.
No. 4,045,229, and hemioxonol compounds described in the respective specifications, and other UV absorbers. Useful mordants are described, for example, in US Pat. No. 3,282,699.
Nos. 3,455,693, 3,438,779, and 3,795,519 can be used.

Polymer latex can be used for the backing layer of the present invention. For example, `` Synthetic resin emulsion (edited by Okudaira, Inagaki Hiroshi, published by Kobunshi Kogyokai (197
8)) '', `` Application of synthetic latex (Takaaki Sugimura, Yasuo Kataoka,
Edited by Soichi Suzuki and Keiji Kasahara, published by Polymer Publishing Association (199
3)) ”,“ Chemistry of synthetic latex (Souichi Muroi, published by Kobunshi Kogakukai (1970)) ”and the like can be used.

Examples of the polymer latex that can be used in the backing layer of the present invention include polymer species such as acrylic resin, vinyl acetate resin, polyester resin, polyurethane resin, rubber resin, vinyl chloride resin, vinylidene chloride resin and polyolefin resin. There is. The polymer may be a linear polymer, a branched polymer, or a crosslinked polymer. Further, the polymer may be a so-called homopolymer in which a single monomer is polymerized, or a copolymer in which two or more kinds of monomers are polymerized. 20% by weight based on the amount of gelatin
The following is preferable, and if it is more than that, the residual color of the dye is deteriorated.

A matting agent is preferably used in the backing layer of the present invention. As a matting agent, at least 20% of the total number of matting agent particles is within a particle size range of ± 20% of the average particle size
A matting agent with 50% coverage is preferred. It is particularly preferably 60% or more, further preferably 75% or more. Matting agents often used in silver halide light-sensitive materials include silicon dioxide, titanium dioxide, magnesium oxide, aluminum oxide, calcium carbonate, hydroxyapatite,
Inorganic substances such as magnesium carbonate, barium sulfate, strontium sulfate, and boron nitride, polymethyl acrylate, polymethyl methacrylate, polyacrylonitrile, polystyrene, cellulose acetate, cellulose acetate, cellulose propionate, silicone,
Examples thereof include fine particle powders of organic substances such as Teflon (registered trademark).

As the shape, a regular or irregular type is used. As the regular matting agent, a spherical matting agent is preferable, but a tabular or cubic one can also be used.
It is also possible to use a matting agent which is impregnated with wax or silicone oil as a sliding agent for the purpose of improving the sliding property, or whose surface is modified with a silano coupling agent, a titano coupling agent or the like. . The matting agent preferably has a particle size of 1 μm to 20 μm, more preferably 3 μm to 10 μm.

The silver halide emulsion used in the silver halide photographic light-sensitive material of the present invention can have an arbitrary halide composition, but especially silver chlorobromide and chloroiodobromide having a chloride content of 50% or more. Silver is preferred. If it contains iodide,
The content is 3 mol% or less, more preferably 1 mol% or less. The shape of the silver halide grains may be regular crystal such as cube or octahedron, and may be irregular or plate-like, but cubic is particularly preferable.

The average size of the silver halide emulsion grains used in the present invention is preferably 0.3 μm or less.
It is particularly preferably 0.25 μm or less, and the coefficient of variation represented by {(standard deviation of particle diameter) / (average particle diameter)} × 100 is 15% or less, more preferably 10% or less. .

For the grain formation of the silver halide emulsion used in the present invention, methods well known in the art such as forward mixing, reverse mixing and simultaneous mixing are used. Among them, it is preferable to use the so-called controlled double jet method, which is one of the simultaneous mixing methods and keeps the pAg in the liquid phase in which particles are formed constant. Further, sulfite salt, lead salt, thallium salt, rhodium salt or its complex salt, iridium salt or its complex salt may be made to coexist in the process of grain formation or physical ripening.

The silver halide emulsion used in the present invention is
It is preferable to sensitize with various chemical sensitizers, and a method commonly used in the art such as a sulfur sensitization method, a selenium sensitization method and a noble metal sensitization method can be used alone or in combination. In the present invention, the gold sulfur sensitization method is particularly preferable.

The silver halide photographic light-sensitive material of the present invention comprises
Known photographic additives can be used for various purposes. These are Research Disclo
Sure Item 17643 (December 1978)
And 18716 (November 1979) 308119
(December 1989) or cited.

The sensitizing dye used in the present invention is characterized by being easily dissolved in water. Known cyanine,
It can be selected from merocyanine, complex cyanine, complex merocyanine, styryl, hemicyanine dyes, etc., but also from the viewpoint of residual color, JP-A-3-171135 and 6-31394.
No. 3, No. 7-287337, and Japanese Patent Application No. 9-259151.
Particularly preferred are the water-soluble sensitizing dyes described in JP-A No. 1994-242242.

The developing agent used in the processing of the silver halide photographic light-sensitive material of the present invention includes hydroquinone and alkylhydroquinone (eg, t-butylhydroquinone,
Dimethylhydroquinone, methylhydroquinone, hydroquinone potassium monosulfonate, etc.), catechol,
Virazol, chlorohydroquinone, dichlorohydroquinone, alkoxyhydroquinone (eg, methoxyhydroquinone, ethoxyhydroquinone, etc.), aminophenol developing agent (eg, N-methyl-P-aminophenol, 2,4-diaminophenol, ascorbin developing agent, N- Methyl-P-aminophenol sulphate etc.), pyrazolones (eg 4-aminopyrazolone etc.), 3-pyrazolidone developing agent (eg 1-phenyl-3-pyrazolidone, 1-phenyl-4,4-dimethyl-3-). Pyrazolidone, 1-phenyl-4-methyl-
3-pyrazolidone, 1-phenyl-4,4-dihydroxymethyl-3-pyrazolidone, 1-phenyl-5-methyl-3-pyrazolidone, 1,5-diphenyl-3-pyrazolidone, 1-p-tolyl-3-pyrazolidone , 1-phenyl-2-acetyl-4,4-dimethyl-3-pyrazolidone, 1-p-hydroxyphenyl-4,4-dimethyl-3-pyrazolidone, 1- (2-benzothiazolyl)
-3-Pyrazolidone, 3-acetoxy-1-phenyl-
3-pyrazolidone and the like), and these are used alone or in combination.

Particularly, a combination of hydroquinone and 3-pyrazolidones or hydroquinone and aminophenols is useful for high temperature rapid treatment. The developing agent is preferably used usually in an amount of 0.1 mol / L to 0.8 mol / L. When a combination of dihydroxybenzenes and 1-phenyl-3-pyrazolidones or p-aminophenols is used, the former is 0.1 mol / L.
˜0.5 mol / L, the latter is preferably used in an amount of 0.06 mol / L or less.

The developer used for processing the silver halide photographic light-sensitive material of the present invention may contain a sufficient amount of sulfite ion as a preservative. Specifically, 0.1 mol /
As the sulfite containing L-1.0 mol / L sulfite ion and giving sulfite ion, sulfite salt of alkali metal such as potassium sulfite, sodium sulfite, potassium metasulfite can be used.

The pH of the developer used in the present invention may be selected to an extent sufficient to give a desired density and contrast to the light-sensitive material, and is preferably less than 11.0.

The alkaline agent used to set the pH is sodium hydroxide, potassium hydroxide, sodium carbonate, potassium carbonate, sodium triphosphate, potassium triphosphate, sodium silicate, potassium silicate or the like. Contains agents and buffers.

As additives used in addition to the above components, sodium bromide, potassium bromide, sodium chloride,
Potassium chloride, potassium iodide, ethylene glycol,
Examples include diethylene glycol and triethylene glycol.

The developing solution further contains an antifoggant (for example,
Benzotriazoles such as 5-nitroindazole, 5-nitrobenzimidazole, 5-methylbenzotriazole and 5-nitrobenzotriazole, thiazoles such as benzothiazole, tetrazoles such as 1-phenyl-5-mercaptotetrazole or British patents Nos. 1,269,268), 3- (5-mercaptotetrazole) benzenesulfonic acid and its derivatives and chelating agents described in JP-A No. 62-212651 as developing unevenness preventing agents. For example, ethylenediaminetetraacetic acid, alkali metal salts thereof, polyphosphate salts, nitriloacetate salts, etc.) can be contained.

The developing treatment temperature is usually selected from 18 ° C to 50 ° C, more preferably 25 ° C to 40 ° C. The processing method of the present invention is particularly suitable for rapid processing using an automatic developing machine, and as the automatic developing machine, any of a roller-conveying type, a belt-conveying type and the like can be used.
The processing time may be short, and the development processing time is within 15 to 60 seconds, preferably within 20 to 40 seconds.

As the fixing solution, those having a generally used composition can be used. The fixing solution includes sodium thiosulfate and ammonium thiosulfate as a fixing agent, and water-soluble aluminum (such as aluminum sulfate, a hardener) as a hardening agent.
Aluminum chloride, potassium alum, etc.), dibasic acid (eg tartaric acid, potassium tartrate, sodium tartrate, sodium citrate, lithium citrate, potassium citrate, etc.) as an aluminum precipitation inhibitor, and sulfite as a preservative. , Bisulfite, and acetic acid, boric acid or the like as a pH buffering agent. The pH of the fixing solution is 3.8 or higher, and more preferably 4.5 to 5.0 in view of the stability of the solution.

The silver halide photographic light-sensitive material of the present invention is developed and fixed, then washed with water and dried. Washing with water is carried out in order to almost completely remove the silver salt dissolved by fixing, and preferably at about 5 ° C to 50 ° C for 10 seconds to 3 minutes. Dry about 30
C. to 80.degree. C., and the drying time may be appropriately changed depending on the ambient conditions, but is usually about 5 seconds to 3 minutes and 30 seconds.

[0047]

The present invention will be described in detail below with reference to examples, but the present invention is not limited to these examples.

Example 1 <Preparation of coating liquid for back coating layer> As a back coating layer, a coating liquid having the following composition was prepared. Amount per 1 m ² Gelatin (compared with calcium decalcified) 3.0 g Dye 1 100 mg Dye 2 30 mg Surfactant S-1 30 mg Surfactant S-2 3 mg Acrylate latex 0.3 g Average particle size 6 micron polystyrene beads 50 mg Hardener Hardeners listed in Table 1 Carbonates Listed in Table 1 Gelatin with calcium ion concentrations of 50 ppm and 400 ppm obtained by the ion exchange method, and calcium ion concentration without ion exchange of 1000 ppm
Comparative gelatin was used to apply a coating solution having the above composition to a polyethylene terephthalate transparent support having a conductive polymer layer using a polystyrene sulfonic acid derivative to prepare a sample.

[0049]

[Chemical 6]

[0050]

[Chemical 7]

Next, the backing of the above sample was applied to the support described in JP-A-2.
The silver halide emulsion layer and the protective layer described in Example 2 of 000-267217 were simultaneously coated.

After the sample thus prepared was annealed at 40 ° C. for 7 days, a roller-conveying type automatic developing machine (Dainippon Screen Mfg. Co., Ltd.) was used by using a developing solution having the following composition and a CF-901 fixing solution manufactured by Mitsubishi Paper Mills. Company-made, LDT-1
060) at 35 ° C. for 90 seconds, and immediately after that, a polyester tape for Nitto platemaking was attached to the edge portion of the sample as a tape test, and after 24 hours, it was strongly separated. The rate at which the backing layer was peeled off together with the tape was evaluated in three grades of ◯, Δ and ×. ○ does not come off at all. △ is less than 1 to 5%, ×
Was evaluated by 5% or more.

Further, the residual color level of the processed sample was evaluated. The evaluation was made by visually observing the level at which five samples were stacked and evaluated in five levels. 5 is the best level, 1 is the worst level, and 4 to 2 are leveled with the difference that the difference in residual color can be clearly distinguished by visual observation. Further, as a test of drying property, the drying level of the sample when 100 sheets of each material were continuously processed was evaluated by three grades of ◯, Δ and ×. If the sample is stuck, it is ×, if it is not sticky, but it is not completely dried, △,
Those completely dried and having no problem were evaluated as ◯. The results are shown in Table 1 below.

[0054]   <Developer formulation> 65g potassium sulfite 15g potassium carbonate Potassium hydroxide The amount required to bring the pH to 10.5 35 g of diethylene glycol Hydroquinone 25g 4-methyl-4-hydroxymethyl-1-phenyl-3-pyrazolidone 1.0 g Diethylenetriamine pentaacetic acid 2.0 g Potassium bromide 5.0g 5-methylbenzotriazole 0.3 g Compound (AS) 0.5g Add water to make 1 liter.

[0055]

[Chemical 8]

[0056]

[Table 1]

From the results shown in Table 1, it can be seen that the backing layer of the present invention containing decalcified gelatin and carbonate has film peeling and excellent drying property and residual color. Further, it is understood that the present invention improves the drying property and film peeling which are the problems of the vinyl sulfone type hardener and further enhances the residual color property. Further, it is understood that the residual color property and film peeling, which are the problems of the triazine-based hardener, are improved.

[0058]

According to the present invention, it is possible to provide a silver halide photographic light-sensitive material in which peeling of the backing layer, drying property and residual color property are simultaneously improved.

Claims (3)

[Claims] 1. A support having a conductive polymer layer,
A silver halide photographic light-sensitive material provided with a backing layer containing a filter dye, wherein the backing layer contains gelatin having a calcium ion concentration of 500 ppm or less as a main binder, and a carbonate. Silver halide photographic light-sensitive material. 2. The silver halide photographic light-sensitive material according to claim 1, wherein the backing layer contains a vinyl sulfone type hardener as a hardener. 3. The silver halide photographic light-sensitive material according to claim 1, wherein the backing layer contains a triazine hardener as a hardener.