JPH05216163A - Support for photographic printing paper and manufacture thereof - Google Patents

Abstract

PURPOSE:To provide a photographic printing paper support by which yellowing is prevented during processing, the rate of fogging with time is reduced during preservation, and a surface resin layer is prevented from cracking. CONSTITUTION:A coating liquid 9 containing an electron-beam-setting unsaturated organic compound is applied by more than one layer to the front surface of a paper base 11 to form an inside coating liquid layer 12a and a coating liquid 3 containing an electron-beam-setting unsaturated organic compound is applied to a molding drum 5 or the molding surface of a film and is irradiated with a first electron beam to form an outermost cured resin layer 7 and the inside coating liquid layer 12a is laid over the outermost cured resin layer 7 and this multilayer body is irradiated with a second electron beam and thereby the inside coating layer 12a and the outermost coating layer 7 are hardened and stuck together to form a surface resin-coated cured layer and the laminate obtained is peeled from the molding surface.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a photographic paper support. More specifically, the present invention suppresses yellowing of the resin coating film due to development processing, maintains sufficient flexibility, and does not cause or suppress fog during long-term storage when used as photographic printing paper. The present invention relates to a support for photographic printing paper and a method for manufacturing the same.

[0002]

2. Description of the Related Art Hitherto, as a support for photographic printing paper, a polyolefin-coated support produced by coating both sides of a paper substrate with a polyolefin resin has been widely used. In such a support, since the polyolefin coating layer is hydrophobic, it is difficult for the processing solution to penetrate into the support during development and fixing processes, as compared with baryta paper, and therefore, the washing time and the drying time are significantly increased. In addition, since the treatment liquid does not penetrate into the paper substrate, expansion and contraction of the support itself is suppressed, and the dimensional stability is excellent.

An inorganic white pigment such as titanium dioxide is mixed in the polyolefin resin coating layer of such a support for the purpose of improving the hiding power or resolution, and such a pigment is dispersible in the resin. However, there is a problem in that the volatile component contained in the pigment causes foaming in the melt extrusion step to cause film cracking of the coating layer. Therefore, the pigment content in the coating layer cannot be increased to a level sufficient to improve the hiding power or resolution. Generally speaking, when using titanium dioxide,
It is difficult to add this in an amount of about 20% by weight or more. Therefore, the photographic printing paper obtained by using such a photographic printing paper support cannot be said to be sufficiently satisfactory in image sharpness.

In recent years, an electron beam curable resin coating layer obtained by coating a support with a so-called electron beam curable resin composed of a resin composition which can be cured by electron beam irradiation, and irradiating it with an electron beam to cure the resin. Have been proposed (for example, JP-B-60-17104, JP-B-60-17105, JP-A-57-49946, etc.). According to this method, it is not necessary to heat and melt the resin composition at a high temperature when forming the coating layer, and the pigment content can be increased to 20 to 80% by weight. Therefore, the image sharpness of the photographic printing paper obtained by using such a support is remarkably improved as compared with the polyolefin resin-coated photographic printing paper.

However, in a photographic printing paper produced by coating a photographic photosensitive layer on an electron beam-curable resin coating layer cured by electron beam irradiation, photographic development chemicals are adsorbed on the resin coating layer in the developing process. After the development process, the phenomenon of yellowing occurs, that is, yellowing occurs, and when the product is developed after storage, the fog density increases to a level that cannot be ignored as a product, It is known that the sensitivity may change. On the other hand, it is also known that the coating film is hard, lacks flexibility, and has problems such as folding cracks.

Various improvement methods have been proposed to solve the above-mentioned fog problem. For example, Japanese Patent Publication No. 1-2149
No. 5 discloses a method of providing a polyethylene coating layer on an electron beam curable resin coating layer as a means for suppressing sensitivity change during storage. But in this way,
The effect of reducing fog cannot be enhanced unless the polyethylene coating layer is thickened, and therefore, the greatest merit when using electron beam curing technology is to sacrifice the improvement of image sharpness. have.

Further, Japanese Patent Application Laid-Open No. 60-144736 discloses that
A method of suppressing a change in photographic sensitivity by disposing a blocking layer between the base paper and the electron beam curable resin coating layer has been proposed. However, the use of the material proposed here as the material for forming the shielding layer is still insufficient in terms of preventing fog during long-term storage.

Use of a specific electron beam curable polymer or electron beam curable monomer for preventing fog and yellowing and softening the coating film (for example, JP-A-59-1243).
No. 36 (acrylic acid ester monomer), JP-A-60-
70446 (urethane resin having a double bond), JP-A-61-204241 (diacrylate, triacrylate, epoxidized acrylate), JP-A-61-23.
6547 (tetraacrylic ester), JP-A-62-1
No. 61049 (hexaacrylate ester), JP-A-62-109046 (polybutadiene-containing resin), JP-A-62-141543 (heterocycle-containing acrylate), JP-A-2-47 (addition of polyhydric alcohol with acrylic acid polymer) Acrylate ester)) has been proposed, but even using these methods, the problem has not yet been sufficiently solved.

Regarding the yellowing of the coating film by the developing solution, there is a relation between the fog density and the flexibility of the coating film, and there is a tendency to contradict the irradiation dose. That is, when a high irradiation dose is used, yellowing of the coating film due to the developing solution can be suppressed to a low level, but fog increases and the flexibility of the coating film deteriorates.
In addition, the paper strength and paper quality of the paper base are also deteriorated. On the other hand, at a low irradiation dose, the generation of fog is suppressed and the flexibility of the coating film is secured to some extent, but the yellowing thereof remarkably increases, and the coating film physical properties such as adhesion and film strength deteriorate. Therefore, in order to improve the yellowing without deteriorating the physical properties of the coating film, together with the selection of the electron beam curable organic unsaturated compound,
Finding all of the above problems is to find a structure and method of a support that does not cause fog, flexibility and paper strength of a paper substrate, and deterioration of paper quality even when an electron dose necessary for crosslinking a coating film is applied. At the same time, it is extremely important for effective resolution.

[0010]

SUMMARY OF THE INVENTION The present invention solves the above-mentioned problems of the prior art, has excellent surface smoothness, maintains high water resistance, and does not increase fog generation due to development processing even after storage. A photographic printing paper support suitable for producing photographic printing paper which has coating film flexibility, suppresses yellowing at the same time, and has excellent photographic characteristics with less deterioration in paper strength and paper quality. It is the one we are trying to provide.

[0011]

The present inventors have succeeded in solving the above-mentioned problems by forming the surface resin coating layer to have a structure of two or more layers, and completed the present invention.

The support for photographic printing paper of the present invention comprises a paper substrate containing natural pulp as a main component, and an electron beam cured product of an unsaturated organic compound formed on one surface of the substrate and curable by electron beam irradiation. And a back resin coating layer formed on the opposite surface of the paper substrate as a main component and containing a film-forming synthetic resin as a main component. It is characterized by having the above laminated structure.

The method for producing a photographic printing paper support of the present invention comprises at least one unsaturated organic compound curable by electron beam irradiation as a main component on one surface of a paper substrate containing a natural pulp as a main component. An inner coating liquid layer is formed, and separately, the outermost coating liquid layer containing an unsaturated organic compound that can be cured by electron beam irradiation as a main component is formed on the molding surface, and the first electron beam is irradiated on this layer. And cured, and the cured outermost cured resin layer and the inner coating liquid layer on the paper base are superposed, and the second electron beam irradiation is applied to the multilayer body to cure and bond it. As a result, a surface-resin-coated cured layer having a laminated structure composed of (1) at least one inner cured resin layer adjacent to the paper substrate and (2) an outermost cured resin layer forming a coated surface of the photographic emulsion is formed. Forming process and on the opposite side of the paper substrate And it is characterized in that it comprises a step of forming a back surface resin coating layer comprising a film-forming synthetic resin as a main component.

[0014]

The structure and operation of the present invention will be described below.
In general, a commercially available electron beam-curable compound composition is applied to a paper substrate containing natural pulp as a main component, and an electron beam is applied to the paper substrate to form an electron beam-curable resin coating layer. The produced photographic printing paper has a problem of so-called yellowing, which is a phenomenon that it is colored yellow after development processing. Although the cause of yellowing is not completely clear, it is believed that the developing agent in the photographic developing chemicals remains adsorbed on the support during the development processing step and is oxidized to cause coloration.

In order to prevent the above yellowing, it is sufficient to reduce the adsorption of the developing agent. For that purpose, it is effective to increase the crosslink density of the coating film of the support, and for this purpose, the resin composition. Means for increasing the irradiation electron dose for curing the resin, increasing the blending amount of the polyfunctional unsaturated organic compound monomer or oligomer, and blending a large amount of the unsaturated organic compound having a relatively small molecular weight, etc. It is possible to keep yellowing low. However, all of these methods not only deteriorate the flexibility of the coating film, but also increase the fog at the time of long-term storage when used as photographic paper when the electron beam irradiation dose is increased. It also had a drawback that the base paper turned yellow due to the impact of the line irradiation.

As a result of various studies on this point, the inventors of the present invention have mainly studied an electron beam cured product of an unsaturated organic compound which is formed on one surface of a paper substrate and can be cured by electron beam irradiation as described above. By forming the surface resin coating layer containing as a component into a laminated structure of two or more layers, and by using an unsaturated organic compound composition curable by electron beam irradiation having at least a high crosslink density in the coating layer of the outermost layer, It was found that the problem of can be effectively solved. That is, by disposing a resin coating layer having a high cross-linking density on the outermost side which is in direct contact with the developing solution in the developing treatment, and arranging a flexible resin coating layer having a relatively low cross-linking density on the inner side not contacting the developing solution, They succeeded in improving flexibility and yellowing at the same time.

The support of the present invention having a laminated structure composed of a plurality of layers as described above contains an electron beam-curable unsaturated organic compound as a main component on at least one surface of a paper base containing natural pulp as a main component. At least one inner layer coating liquid is applied, and the outermost layer coating liquid containing an electron beam-curable unsaturated organic compound as a main component is applied wet-on-wet on the inner coating liquid layer, It can be manufactured by irradiating this multilayer body with an electron beam.

As a second method, the inner layer coating solution is applied, the inner coating layer is irradiated with a first electron beam, and the outermost layer coating solution is tandemly applied onto the obtained inner cured resin layer. Can be applied by wet-on-dry coating and irradiating the obtained multilayer body with a second electron beam.

As a third method, contrary to the second method, the outermost layer coating liquid is applied onto another suitable molding surface, for example, a smooth surface such as a metal drum, plastic, or process paper. Wet the inner coating liquid layer formed by applying the first electron beam to the outermost coating liquid layer to form the outermost cured resin layer, and then applying the inner layer coating liquid onto the paper substrate separately. It can be manufactured by stacking the outermost cured resin layer on the coated surface from the molding surface by transfer layering, and irradiating the layered body with the second electron beam.

As a fourth method, the inner coating liquid layer and the outermost coating liquid layer are wet-on-wet laminated by the above transfer coating method, and this laminated body can be manufactured by irradiating an electron beam. ..

Whichever of the above-mentioned methods is used, it is possible to improve the degree of freedom of coating in the heavy coating by improving the coating property by imparting a unique function to each layer by dividing the coating layer into two or more layers. to enable. Further, when transfer coating is adopted, the smoothness of the surface is further improved.

According to the present invention, no matter which of the above coating methods is adopted, the surface resin coating / curing layer containing the electron beam curable unsaturated organic compound is divided into at least two layers to improve the coating property and smoothness. It is to let.

In addition, according to the present invention, a plurality of unsaturated organic compounds used in the inner layer and outermost layer of the surface resin coating / cured layer are combined in various ways to share various functions, thereby reducing yellowing and fog. And to increase the flexibility of the coating.

Further, according to the present invention, the electron beam irradiation dose is divided and given to the inner coating liquid layer and the outermost coating liquid layer, thereby reducing yellowing and fog and increasing the flexibility of the coating film. It is to be.

Further, according to the present invention, the outermost coating liquid layer is formed by pressing it against the molding surface, thereby making the surface of the surface resin coating and cured layer smoother.

In the multi-layer laminated support of the present invention, in order to balance the flexibility of the surface resin coated and cured layer with the prevention of yellowing and fogging, first, the coating liquid amounts of the outermost layer and the inner layer are specified. Preferably. That is, the coating amount of the entire surface coating liquid layer is preferably 5 g / m ² or more and 60 g or more after curing.
/ M ² or less, more preferably 15 g / m ² or more and 60 g /
When it is m ² or less, sufficient smoothness, hiding power and resolution are maintained as a support for photographic printing paper.

Whatever resin is used, in order to fully exert the function of the outermost layer and ensure the flexibility and prevention of yellowing of the coating film, the coating amount after curing is 0.5 g /
It is preferably m ² or more and 20 g / m ² or less, and more preferably 1 g / m ² or more and 10 g / m ² or less. When the coating amount is less than 0.5 g / m ² , sufficient smoothness and yellowing prevention cannot be ensured in the resulting support, and it is 2
When it exceeds 0 g / m ² , sufficient flexibility may not be ensured in the resulting support, and folding cracks may occur in the surface-resin-coated cured layer.

In the present invention, as the electron beam curable organic compound used in the resin coating solution for the outermost layer for forming the coated surface of the photographic emulsion in the surface resin coated cured layer, a highly crosslinked resin layer is formed. As long as it is possible, it may be a monomer alone, an oligomer alone, or a mixture thereof, and the kind of compound is not particularly limited, but an unsaturated organic compound having 4 or more functional groups is mainly used. It is preferably contained as a component. There is no limitation on the type of organic compound that can be used to form the inner layer located on the paper substrate side, but those having less than 4 functional groups are desirable. With respect to this inner resin cured layer, since there is no risk of yellowing due to development processing, there is no need to increase the crosslinking density, and a resin with excellent flexibility can be selected.

The unsaturated organic compound that can be cured by electron beam used in the present invention can be selected from the following compounds, for example. (1) Aliphatic, alicyclic and araliphatic 1 to 6 valent alcohol and polyalkylene glycol acrylate compounds (2) Aliphatic, alicyclic and araliphatic 1 to 6 valent Acrylate compounds obtained by adding alkylene oxide to alcohol (3) Polyacryloylalkyl phosphates (4) Reaction product of carboxylic acid, polyol and acrylic acid (5) Isocyanate, polyol and acrylic acid (6) Reaction product of epoxy compound and acrylic acid (7) Reaction product of epoxy compound, polyol and acrylic acid

More specifically, as the electron beam-curable unsaturated organic compound, polyoxyethylene epichlorohydrin-modified bisphenol A diacrylate, dicyclohexyl acrylate, epichlorohydrin-modified polyethylene glycol diacrylate, 1,6-hexanediol diacrylate. , Hydroxybivalic acid ester neopentyl glycol diacrylate, nonylphenoxy polyethylene glycol acrylate, ethylene oxide modified phenoxyphosphoric acid acrylate,
Ethylene oxide modified phthalate acrylate, polybutadiene acrylate, caprolactan modified tetrahydrofurfuryl acrylate, tris (acryloxyethyl) isocyanurate, trimethylolpropane triacrylate, pentaerythritol triacrylate,
Pentaerythritol tetraacrylate, dipentaerythritol hexaacrylate, polyethylene glycol diacrylate, 1,4-butadiene diol diacrylate, neopentyl glycol diacrylate,
Further, neopentyl glycol-modified trimethylolpropane diacrylate and the like can be used.

In the present invention, these compounds may be used singly or in combination of two or more thereof, and as the unsaturated organic compound used in the outermost layer, a functional group having 4 or more functional groups is added in order to give high crosslinking. As mentioned above, the compound having a group is particularly advantageously used.

When used as photographic printing paper, the surface resin coated and cured layer of the present invention preferably contains a white pigment for the purpose of improving the sharpness of the image. Titanium dioxide (anatase type and rutin type) is mainly used as the white pigment, but other than this, barium sulfate, calcium carbonate, aluminum oxide, zinc oxide, magnesium oxide, magnesium hydroxide, etc. can all be used. Is. Further, other additives can be used if necessary.

The content of the white pigment is preferably 20 to 80% by weight based on the total solid weight of the surface resin coated and cured layer. If the content is less than 20% by weight, the sharpness of the photographic image on the photographic paper obtained may not be sufficient, and if it exceeds 80% by weight, the flexibility of the resin coating layer obtained may decrease and the film May crack.

To disperse the white pigment in the electron beam-curable unsaturated organic compound as described above, a three-roll mill (three-roll mill), a two-roll mill (two-roll mill),
Cowles dissolvers, homomixers, sand grinders, planetary mixers, ultrasonic dispersers and the like can be used.

The electron beam curable unsaturated organic compound composition may be applied to the molding surface or the paper substrate surface by, for example, bar coating, blade coating, squeeze coating, air knife coating, roll coating,
Either a gravure coating method or a transfer coating method may be used. For this purpose, a fountain coater or slit die coater system can be used. Especially when the surface of a metal drum is used as the molding surface, a roll call method using a rubber roll or an offset gravure coating method is used to prevent scratches on the molding surface, and a non-contact type fountain is used. A coater or slit die coater method is advantageously used.

As described above, there are four types of methods for carrying out the surface-resin-coated cured layer having a laminated structure of two or more layers according to the present invention. In any of these four methods, it is preferable that the outermost coating liquid layer contains an unsaturated organic compound having four or more functional groups as a main component, and the coating order of the coating liquid layers and the coating liquid layers. The amount of electron beam irradiation to is varied depending on the coating method.

By using an unsaturated organic compound having a functional group of 4 or more having a high crosslink density in the outermost layer, the crosslink density of the outermost layer is increased to prevent yellowing, and the inner layer has a low crosslink density. When the purpose is to increase the flexibility of the entire coating film by applying a material, the second method is not preferable because the inner layer is irradiated with a large amount of electron beams. In this case, the first and fourth methods are both preferable because they are performed once by electron beam irradiation. However, in order to improve the smoothness of the surface coating layer, transfer the cured resin layer from the molding surface.
The fourth method of coating is preferred. The third method is a transfer method and is the most preferable method for forming the outermost layer having high smoothness and high crosslink density, since the outermost layer is irradiated with a large amount of electron beams.

The effect of the present invention can be obtained particularly advantageously by adopting the above-mentioned third method, that is, the method of the present invention. The apparatus used in the present invention will be described with reference to the accompanying drawings. These drawings are schematic views showing an embodiment of the method of the present invention.

In the coating liquid coating and curing equipment 1 shown in FIG. 1, the electron beam curable resin composition 3 to form the outermost layer.
Is coated on the surface of the metal drum 5 that provides the molding surface from the container 2 using coaters 4a and 4b such as an offset gravure coater to form the outermost coating liquid layer 7a, and then the coating liquid layer 7a is the first layer. The outermost cured resin layer 7 is formed by being cured by using the electron beam irradiation device 6.

On the other hand, the electron beam curable resin composition 9 for inner coating in the container 8 is coated on the paper substrate 11 using the coaters 10a, 10b, 10c to form an inner coating liquid layer which forms a flexible resin. 12a is formed, and the inner coating liquid layer 12a is superposed on the outermost cured resin layer 7 on the metal drum 5 by the guide roll 13, and the multilayer body is cured by the irradiation of the second electron beam irradiation device 14. After that, the support 16 made of a laminate of the paper substrate and the surface resin coating and cured layer which is cured and adhered by the guide roll 15 is peeled from the molding surface of the metal drum.

In FIG. 2, the film 1 is used as a molding surface.
A case of utilizing 7 is shown. That is, a polymer film such as a polyester film is used for the molding surface instead of the metal drum. In this case, the irradiation from the second electron beam irradiation device 14 may be irradiated through the molding film 17 as shown in FIG. 2, or the back surface of the paper substrate opposite to the molding surface film 17 may be irradiated. May be irradiated from. This film can be wound up and reused again, but in that case, it may be formed into an endless belt. The molding surface film is not necessarily a polymer film, and may be a belt-shaped metal film, and the metal film may be an endless film. In the above method, two or more inner coating layers may be laminated and coated. In this case, the compositions used after coating may be the same as or different from each other.

In any of the above cases, the outermost layer has a total of 2 layers.
It has a high crosslink density because it is repeatedly irradiated with electron beams, and is therefore extremely effective for preventing yellowing due to development.

According to the present invention, since the amount of electron beam irradiation to the paper substrate can be suppressed to a low level, discoloration of the paper substrate due to electron beam irradiation can be suppressed, and further, the electron beam irradiation to the paper substrate can be suppressed. It is also possible to suppress the fog caused by long-term storage.

The electron beam accelerator used for electron beam irradiation is not particularly limited in its system, and for example, an electron beam irradiation device such as a Van de Graaff scanning system, a double scanning system or a curtain beam system can be used. However, among them, the curtain beam system, which is relatively inexpensive and has a large output, is effectively used. The acceleration voltage at the time of electron beam irradiation is preferably 100 to 300 KV, and the absorbed dose is 0.1 to 6 M
It is preferably rad, and particularly preferably 0.2 to 4 Mrad.

The oxygen concentration in the atmosphere during electron beam irradiation is preferably 500 ppm or less. When the oxygen concentration exceeds 500 ppm, oxygen acts as a retarder for the polymerization reaction, and the resin composition may be insufficiently cured.
In the case of the third transfer method in which the second electron beam irradiation is performed after superimposing it on the coating film cured by the first electron beam irradiation, the electron beam curing coating liquid directly contacts the air during the electron beam irradiation. Therefore, it is not necessary to particularly reduce the oxygen concentration in the atmosphere during electron beam irradiation, but for the purpose of suppressing ozone generation due to electron beam irradiation, or for cooling windows that generate heat when the electron beam passes, etc. Of course, there is no problem in using an inert gas for the above purpose.

In the support of the present invention, the film-forming synthetic resin used to form the backside resin coating layer is a polyolefin resin used in the production of a conventional support for photographic printing paper, or the above-mentioned one. An electron beam curing resin or the like can be used.

Examples of the polyolefin resin for forming the backside resin coating layer include homopolymers of ethylene and α-olefins such as propylene, at least two copolymers of the above olefins, and various polymers of these. It can be selected from a mixture of at least two kinds. Particularly preferred polyolefin resins include low density polyethylene, high density polyethylene, linear low density polyethylene,
And mixtures of these. The molecular weight of the polyolefin resin is not particularly limited, but is usually 20,000 to 20.
Those in the range of 10,000 are used. If necessary, a small amount of an antioxidant and a lubricant may be added to the polyolefin resin. To form the backside resin coating layer using a polyolefin resin, a usual melt extrusion coating can be used.

The backside resin coating layer can also be formed of an electron beam curable unsaturated organic compound. For this purpose, all the compounds used for forming the surface resin coating layer can be used. Further, the method for forming the back surface resin coating layer may be a laminated structure as in the case of the above-mentioned front surface resin coating layer. The weight of the backside resin coating layer is not particularly limited, but generally it is preferably in the range of 10 to 40 g / m ² .

The paper substrate used in the present invention is usually 50-
It has a weight of 300 g / m ² and has a smooth surface. As the paper substrate, any of those generally used for a photographic printing paper support can be used. As the natural pulp forming the paper substrate, generally, those containing, as a main component, softwood pulp, hardwood pulp, mixed softwood hardwood pulp, etc. are widely used. Further, the paper substrate may contain a filler.

Further, it is effective to incorporate a magnesium compound such as a hydroxide, an oxide or a salt into the paper substrate for the purpose of preventing fog which occurs during long-term storage when used as a photographic printing paper (Japanese Patent Application No. Hei 3). -172). Further, the paper substrate may be blended with additives such as a sizing agent, a fixing agent, a paper strengthening agent, a filler, an antistatic agent, a pH adjusting agent, a pigment and a dye which are generally used in papermaking. Further, a surface sizing agent, a surface paper strength agent, a pigment, a dye, an antistatic agent or the like may be appropriately applied on the surface.

[0051]

EXAMPLES The constitution and effects of the present invention will be further described with reference to the following examples, but the present invention is of course not limited to these embodiments.

Example 1 A back surface of a paper substrate having a basis weight of 180 g / m ² was subjected to a surface activation treatment by corona discharge, and a polyethylene resin was melt-extrusion coated on the back surface of the paper substrate, and the coating amount was 30 g / m ² . A backside resin coating layer was formed.

Separately, an electron beam curable organic compound-white pigment mixed composition (composition 1) for forming the outermost surface resin coating layer was prepared as follows. Composition 1 Ingredient weight dipentaerythritol hexaacrylate 80 parts by weight (trademark: Beam Set 700, Arakawa Chemical Industries, Ltd.) Titanium dioxide 20 parts by weight (trademark: TIPAQUE A-220, manufactured by Ishihara Sangyo Kaisha) paint mixture of the components An electron beam curable composition was prepared by mixing and dispersing with a conditioner for 1 hour.

This composition was applied onto the surface of a chrome-plated metal plate used as a molding surface using a wire bar so that the coating amount after curing was 5 g / m ² , and this coating was performed. Acceleration voltage in liquid layer: 175KV, absorbed dose:
The outermost cured resin layer was formed by irradiating an electron beam under the condition of 2 Mrad to cure it.

Separately, the following electron beam curable organic compound-white pigment mixed composition for inner layer (composition 2) was prepared. Composition 2 Ingredient weight difunctional urethane acrylate oligomer 36 parts by weight (trademark: Beam Set 550B, manufactured by Arakawa Chemical Industries) bifunctional acrylate monomer 24 parts by weight (trademark: Aronix M-220, manufactured by Toagosei) titanium dioxide 40 weight Parts (Trademark: Taipaque A-220, manufactured by Ishihara Sangyo) The mixture of the above components was mixed and dispersed for 1 hour with a paint conditioner to prepare an electron beam curable composition.

This composition was applied onto the surface of the above-mentioned paper substrate using a wire bar so that the coating amount after curing was 25 g / m ² , and this coating liquid layer was applied onto the above-mentioned metal plate molding surface. It is superposed on the outermost cured resin layer of, and the laminated body is accelerating voltage: 175 KV from the back side of the paper substrate, and the absorbed dose: 2M.
The electron beam was irradiated under the condition of rad to cure and bond it. Next, the laminate obtained in the above step was peeled from the metal plate molding surface to prepare a support for photographic printing paper.

In order to test the yellowing due to the development treatment of the obtained photographic printing paper support, the test support was subjected to development using an automatic dust processor (trademark: RCP20, manufactured by Durst Co.).

In order to evaluate the yellowing of the developed test support, TAPPI-T524 (1979 version) "L
The b value before and after the development treatment is measured according to "ab measuring method",
The value obtained by subtracting the b value before development processing from the b value after development processing (Δ
The evaluation was carried out using (b value) as an index of yellowing. The results of this test are shown in Table 1. Those having a Δb value of 1.0 or less are practical, but those exceeding 1.0 are not practical.

To evaluate the flexibility, the test resin was wound around a round rod having a diameter of 0.2 cm with the surface resin coating layer on the outside, and the cracking condition was visually observed. Evaluation was made on a three-point scale, with 3 points indicating no cracks at all, 2 points indicating slight cracks, and 1 point indicating cracks. 3 points and 2
The point one is practical, but the one point is not practical. The results of this test are shown in Table 1.

Example 2 A photographic printing paper support was prepared in the same manner as in Example 1. However, instead of the metal plate as a molding surface, a thickness of 75 μm
The polyester film of was used. Table 1 shows the result of the test conducted in the same manner as in Example 1.

Example 3 A photographic printing paper support was prepared in the same manner as in Example 1.
However, the manufacturing process was performed as follows. The coating composition 2 was applied to the surface of the above-mentioned paper base using a wire bar so that the coating amount after curing was 25 g / m ² , and the coating composition 1 was further coated on the inner coating liquid layer. Wet on
The wet coating is applied to form the outermost coating liquid layer, and the surface of the obtained multi-layered body is pressed against the metal plate molding surface, and the multi-layered body is accelerating voltage: 175 KV, absorbed dose: 2
The electron beam was irradiated under the condition of Mrad to cure and bond it. Next, the laminate obtained in the above step was peeled from the metal plate molding surface to obtain a support for photographic printing paper. Table 1 shows the result of the test conducted in the same manner as in Example 1.

Example 4 A support for photographic printing paper was prepared in the same manner as in Example 1.
However, the manufacturing process was performed as follows. The coating composition 2 was applied to the surface of the paper substrate described above using a wire bar so that the coating amount after curing was 25 g / m ² to form an inner coating liquid layer, on which an accelerating voltage: 175 KV The absorbed dose: 2 Mrad was irradiated with an electron beam to form an inner cured resin layer. Next, the outermost coating liquid layer is formed by applying the coating composition 1 onto the above-mentioned inner cured resin layer in tandem in a wet-on-dry manner so that the coating amount after curing is 5 g / m ^2. Then, the surface of the obtained multilayer body is pressed against the metal plate molding surface, and the accelerating voltage: 1 is again applied from the back surface of the paper substrate.
The outermost cured resin layer was formed by irradiating an electron beam under the conditions of 75 KV and absorbed dose: 2 Mrad, and this was bonded to the inner cured resin layer. Next, the laminate obtained in the above step was peeled from the metal plate molding surface to obtain a support for photographic printing paper. Table 1 shows the result of the test conducted in the same manner as in Example 1.

Example 5 A support for photographic printing paper was prepared in the same manner as in Example 1. However, the manufacturing process was performed as follows. The coating composition 1 was applied on the above-mentioned metal plate molding surface using a wire bar so that the coating amount after curing was 5 g / m ² to form the outermost coating liquid layer. On the other hand, the composition 2 was applied onto the surface of the paper substrate described above using a wire bar so that the coating amount after curing was 25 g / m ² , and the inner coating liquid layer was formed into the metal plate described above. Wet-on-wet overlay on the outermost coating liquid layer on the surface, and this multilayer body is cured by irradiating it with an electron beam from the back side of the paper substrate under the conditions of accelerating voltage: 175 KV and absorbed dose: 2 Mrad.・
Glued. Next, the laminate obtained in the above step was peeled from the metal plate molding surface to prepare a support for photographic printing paper.
Table 1 shows the result of the test conducted in the same manner as in Example 1.

Example 6 A support for photographic printing paper was prepared in the same manner as in Example 1.
However, the coating amount of the composition 1 after curing is 1.2 g / m 2.
^It was applied so as to be ² . Table 1 shows the result of the test conducted in the same manner as in Example 1.

Example 7 A photographic printing paper support was prepared in the same manner as in Example 1.
However, the composition 1 was applied such that the coating amount after curing was 6 g / m ² . Table 1 shows the result of the test conducted in the same manner as in Example 1.

Example 8 A support for photographic printing paper was prepared in the same manner as in Example 1.
However, the amount of the composition 1 coated after curing was 10 g / m ²
Was applied so that Table 1 shows the result of the test conducted in the same manner as in Example 1.

Example 9 A support for photographic printing paper was prepared in the same manner as in Example 1.
However, the electron beam curable organic compound for the outermost layer of the following composition-
A white pigment mixed composition (Composition 3) was prepared and used in place of Composition 1 above.

[0068] Composition 3 Ingredient amount 80 parts by weight of propionic acid-modified dipentaerythritol pentaacrylate (TM: KARAYAD D-310, manufactured by Nippon Kayaku) titanium dioxide 20 parts by weight (trademark: TIPAQUE A-220, manufactured by Ishihara Sangyo Kaisha ) Table 1 shows the results of tests conducted in the same manner as in Example 1.

Example 10 A support for photographic printing paper was prepared in the same manner as in Example 1.
However, the electron beam curable organic compound for the outermost layer of the following composition-
A white pigment mixed composition (Composition 4) was prepared and used in place of Composition 1.

[0070] Composition 4 Ingredient weight pentaerythritol tetraacrylate 50 parts by weight (trademark: Beam Set 710, manufactured by Arakawa Chemical Industries) Titanium dioxide 50 parts by weight (trademark: TIPAQUE A-220, manufactured by Ishihara Sangyo Kaisha) as in Example 1 The results of tests conducted in the same manner are shown in Table 1.

Example 11 A support for photographic printing paper was prepared in the same manner as in Example 1.
However, an electron beam curable organic compound-white pigment mixed composition for the inner layer (composition 5) having the following composition was prepared, and this was used instead of the composition 2. Composition 5 Ingredient weight trifunctional urethane acrylate oligomer 60 parts by weight (trademark: New Frontier R-1301, manufactured by Dai-ichi Kogyo Seiyaku Co.) titanium dioxide 40 parts by weight (trademark: TIPAQUE A-220, Ishihara Sangyo Kaisha Ltd.) Example 1 Table 1 shows the results of the test conducted in the same manner as in.

Comparative Example 1 A support for photographic printing paper was prepared in the same manner as in Example 1.
However, the manufacturing process was performed as follows. Composition 1
Is coated on the surface of the metal plate molding surface described above using a wire bar so that the coating amount after curing is 25 g / m ² to form a coating liquid layer, on which the paper substrate is coated. Overlapping the surface, from the back of the paper substrate, acceleration voltage: 175KV,
After absorbing the electron beam under the condition of absorbed dose: 2 Mrad to cure the inner coating liquid layer, the laminate obtained in the above step was peeled from the metal plate molding surface to obtain a support for photographic printing paper. The results of the test conducted in the same manner as in Example 1 are shown in Table 1.
Shown in.

Comparative Example 2 A support for photographic printing paper was prepared in the same manner as in Comparative Example 1.
However, instead of the composition 1, the composition 2 was used. The results of the test conducted in the same manner as in Example 1 are shown in Table 1.
Shown in.

Comparative Example 3 A support for photographic printing paper was prepared in the same manner as in Comparative Example 1.
However, instead of the composition 1, a mixture of the composition 1 and the composition 2 in a weight ratio of 1: 1 was used.
Table 1 shows the result of the test conducted in the same manner as in Example 1.

Comparative Example 4 A photographic printing paper support was prepared in the same manner as in Example 1.
However, the coating amount of the composition 1 after curing is 0.3 g / m 2.
^It was applied so as to be ² . Table 1 shows the result of the test conducted in the same manner as in Example 1.

Comparative Example 5 A support for photographic printing paper was prepared in the same manner as in Example 1.
However, the coating amount of the composition 1 after curing was 25 g / m ²
Was applied so that Table 1 shows the result of the test conducted in the same manner as in Example 1.

Comparative Example 6 A support for photographic printing paper was prepared in the same manner as in Example 9.
However, the composition 1 was used in place of the composition 2. The results of the test conducted in the same manner as in Example 1 are shown in Table 1.
Shown in.

Comparative Example 7 A support for photographic printing paper was prepared in the same manner as in Example 10. However, the composition 1 was used in place of the composition 2. Table 1 shows the result of the test conducted in the same manner as in Example 1.

[0079]

[Table 1]

[0080]

The photographic printing paper support of the present invention can greatly reduce the general drawback of providing an electron beam-curable resin layer, that is, the yellowing of the coating film during development processing.
In addition, it is possible to maintain sufficient flexibility, and therefore, it is extremely effective in practice.

[Brief description of drawings]

FIG. 1 is a process explanatory view in the case where a two-layer structure surface resin coating of a support for photographic printing paper of the present invention is formed using a metal drum as a molding surface.

FIG. 2 is a process explanatory view in the case of forming a resin coating having a two-layer structure on the support for photographic printing paper of the present invention by using a film material as a molding surface.

[Explanation of Codes] 1 ... Coating liquid coating and curing facility 2 ... Paint container 3 ... Outermost layer electron beam curable resin composition 4a, 4b, 4c ... Coater 5 ... Molding drum 6 ... First electron beam irradiation device 7a Outermost coating liquid layer 7 Outermost cured resin layer 8 Paint container 9 Electron beam curable resin composition for inner layers 10a, 10b, 10c Coater 11 Sheet-like substrate 12a Inner coating liquid layer 12 Inside Cured resin layer 13, 13a, 13b ... Guide roll 14 ... Second electron beam irradiation device 15, 15a, 15b ... Guide roll 16 ... Support 17 ... Molding film

Front Page Continuation (72) Inventor Masafumi Kobayashi 1-10-6 Shinonome, Koto-ku, Tokyo Oji Paper Co., Ltd. Product Research Laboratory

Claims (2)

[Claims] 1. A paper substrate containing natural pulp as a main component, and a surface resin coating and curing containing an electron beam cured product of an unsaturated organic compound which is formed on one surface thereof and can be cured by electron beam irradiation as a main component. And a backside resin coating layer formed on the opposite surface of the paper substrate and containing a film-forming synthetic resin as a main component.
A support for photographic printing paper, which has a laminated structure of more than one layer. 2. At least one inner coating layer containing, as a main component, an unsaturated organic compound curable by electron beam irradiation is formed on one surface of a paper substrate containing natural pulp as a main component, and a molding surface is separately formed. An outermost coating liquid layer containing, as a main component, an unsaturated organic compound that can be cured by electron beam irradiation is formed thereon, and the first outer layer is irradiated with a first electron beam to be cured, and this cured outermost cured resin is formed. Layer and the inner coating liquid layer on the paper base are superposed, and the multilayer body is subjected to a second electron beam irradiation to cure and bond it, whereby (1) at least one layer adjacent to the paper base. Inner cured resin layer of (2)
A step of forming a surface resin cured layer having a laminated structure consisting of an outermost cured resin layer forming a coated surface of the photographic emulsion, and a film-forming synthetic resin as a main component on the opposite surface of the paper substrate. A method for producing a support for photographic printing paper, which comprises the step of forming a backside resin coating layer.