JPH09152679A - Base for photographic printing paper - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a base for photographic printing paper having excellent image sharpness without the occurrence of stripe patterns like rainbow by the interference of light on the surface of the photographic paper. SOLUTION: This base has a sheet-like base material, a front surface resin coating layer which is formed on the one surface of this sheet-like base material and consists of the electron beam cured matter of an electron beam curing type resin compsn. and a rear surface resin coating layer which is formed on the other surface of the sheet-like base material and contains a film formable synthetic resin as an essential component. The front surface resin coating layer contains titanium dioxide and the content of pigments having a refractive index of <=1.8 in the entire pigment is 20 to 80wt.%.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a photographic printing paper support. More specifically, the present invention is a cured product of a coating composition (hereinafter, referred to as an electron beam curable resin composition) containing an unsaturated organic compound that is cured by irradiation with an electron beam as a main component and a pigment. The present invention relates to a support for photographic printing paper having a surface resin coating layer consisting of, and when a photographic emulsion layer is provided on the surface resin coating layer to form a photographic printing paper, interference of light generated on the surface of the photographic printing paper The present invention relates to a support for photographic printing paper, which is capable of preventing a striped pattern due to, and has good image sharpness.

[0002]

2. Description of the Related Art Conventionally, as a support for photographic printing paper,
So-called baryta paper is used, which is manufactured by applying a white pigment such as barium sulfate to both sides of paper which has been imparted with strong size and high strength. But,
In recent years, instead of the baryta paper, a polyolefin-coated support made by coating both sides of a paper base with a polyolefin resin has been widely used. In such a support, since the polyolefin surface resin coating layer is hydrophobic, the processing liquid is less likely to penetrate into the support during the development and fixing processes as compared with baryta paper, and therefore the washing time and the drying time are reduced. Has the advantage of being significantly shortened, and since the processing liquid does not penetrate into the paper substrate, the expansion and contraction of the photographic paper support itself is suppressed, and it has the advantages of excellent dimensional stability. Have

However, an inorganic white pigment such as titanium dioxide is mixed with the polyolefin surface resin coating layer of such a support for the purpose of improving the hiding power or resolution, and such a pigment is incorporated into the resin. Has poor dispersibility, and foams in the melt extrusion process due to volatile components contained in the pigment, causing film cracks in the resin coating layer. Therefore, the pigment content in the resin coating layer cannot be increased to a level sufficient to improve the hiding power or resolution. Generally speaking, when titanium dioxide is used, it is difficult to mix it in a large amount exceeding about 20% by weight. Therefore, the photographic printing paper obtained by using such a conventional support for photographic printing paper cannot be said to be sufficiently satisfactory in image sharpness.

In recent years, a support for photographic paper has been proposed which has an electron beam curable resin coating layer obtained by coating an electron beam curable resin composition on a sheet-like substrate and irradiating it with an electron beam to cure the resin. (For example, Japanese Patent Publication No. 60-17104,
JP-B-60-17105, JP-A-57-49946, etc.). According to this method, it is not necessary to heat the resin composition to a high temperature when forming the resin coating layer, and the pigment content can be increased up to 20 to 80% by weight. Therefore, such a photographic printing paper can be used. The image sharpness of the photographic printing paper obtained by using the substrate for use is remarkably improved as compared with the polyolefin resin-coated photographic printing paper.

In particular, a metallic cylindrical rotating body as disclosed in Japanese Patent Publication No. 60-17105 and Japanese Patent Publication No.
After the sheet-shaped substrate coated with the electron beam-curable resin composition is pressed against a very smooth and highly glossy molding surface such as a sheet-shaped film disclosed in Japanese Patent No. 69932, electron beam irradiation is performed. The support for photographic printing paper obtained by curing according to the method described above had an advantage of having a very smooth surface and a high gloss and having a good surface property, reflecting a very good surface property of the molding surface.

However, a photographic printing paper support having a coating layer made of such an electron beam curing resin has a high pigment content as described above and has a very good surface property. There was a problem. That is, when a photographic emulsion layer is formed on a photographic paper support obtained by applying an electron beam curable resin composition and pressing it against the molding surface, the surface of the photographic paper is It became clear that there is a problem that light interference occurs and a rainbow-like striped pattern occurs, and improvement thereof has been desired.

In order to solve the above problems, the present inventors formed a surface resin coating layer provided on the surface of a sheet-shaped substrate in Japanese Patent Application No. 6-59087 from a laminate of electron beam curable resins, And, in this surface resin coating layer, the blending ratio of the pigment blended in the coating composition forming the outermost resin coating layer is 25 to 40% by weight of the total solid content of the outermost resin coating layer.
In addition, it has been proposed that the blending ratio of the pigment to be blended in the inner resin coating layer be 10% by weight or more higher than the blending ratio of the outermost resin coating layer. When the photographic emulsion layer is further formed on the surface resin coating layer thus obtained to produce a photographic printing paper, light interference does not occur on the surface of the photographic printing paper, and the surface of the photographic printing paper looks like a rainbow. Although no striped pattern was generated, it could not be said that the image sharpness was sufficiently satisfactory because the blending ratio of the pigment blended in the outermost resin coating layer was low.

[0008]

DISCLOSURE OF THE INVENTION The present invention solves the above problems of a conventional photographic printing paper support having an electron beam curable resin coating layer, and the surface of the photographic printing paper is covered with a rainbow image due to light interference. An object of the present invention is to provide a support for photographic printing paper, which does not generate such a striped pattern (hereinafter referred to as a rainbow striped pattern) and has excellent image sharpness.

[0009]

Means for Solving the Problems The inventors of the present invention have conducted diligent research to solve the above problems of a support for photographic printing paper having an electron beam curable resin coating layer, and as a result, Among the pigments contained in the surface resin coating layer on the side of the support on which the photographic emulsion layer is formed, the pigment having a refractive index of 1.8 or less is blended to prevent the occurrence of a rainbow stripe pattern.
It was found that high image sharpness can be obtained, and the present invention has been completed.

That is, the support for photographic printing paper of the present invention comprises a sheet-shaped substrate and an electron beam-cured product of an electron beam-curable resin composition formed on one surface of the sheet-shaped substrate. And a back surface resin coating layer formed on the other surface of the sheet-shaped substrate and containing a film-forming synthetic resin as a main component, and the surface resin coating layer comprises titanium dioxide. Contains and has a refractive index of 1.8 in all pigments
The content of the following pigments is 20 to 80% by weight.

Further, the support for photographic printing paper of the present invention comprises a sheet-shaped substrate and an electron beam-cured product of an electron beam-curable resin composition which is formed on one surface of the sheet-shaped substrate. Surface resin coating layer, and a back surface resin coating layer formed on the other surface of the sheet-shaped substrate, and having a film-forming synthetic resin as a main component, the surface resin coating layer,
It is composed of a laminate of at least two layers including an inner resin coating layer adjacent to the sheet-shaped substrate and an outermost resin coating layer arranged on the outermost side, and the outermost resin coating layer contains titanium dioxide, and The content of the pigment having a refractive index of 1.8 or less in all pigments is 20 to 80% by weight of the amount of the pigment compounded.

In the present invention, the surface resin coating layer contains a pigment having a refractive index of 1.8 or less to prevent the formation of rainbow stripes and a refractive index of 1.8 to improve the image sharpness. Larger pigments are contained. However,
When the surface resin coating layer is a laminate of two or more layers consisting of the outermost resin coating layer and the inner resin coating layer, the refractive index to be blended in the outermost resin coating layer to prevent the rainbow pattern is 1.
A pigment of 8 or less and a pigment to be blended for improving the image sharpness may be contained. According to this method, it is possible to use a resin having good flexibility for the inner resin coating layer that does not come into direct contact with the developing solution during development, which is an effective means for improving the flexibility of the surface resin coating layer. .

In the present invention, the reason why both the prevention of the rainbow stripe pattern and the high image sharpness are compatible is that the coating composition for forming the surface resin coating layer contains a pigment having a refractive index of 1.8 or less at 20 to 20% of the pigment content. 80% by weight is included. Since the pigment having a low refractive index has a high effect of transmitting light, the light incident on the surface resin coating layer transmits the pigment having a low refractive index. for that reason,
Light is diffused in the surface resin coating layer. Therefore, when a photographic emulsion layer is provided on the surface resin coating layer to form a photographic printing paper, a rainbow stripe pattern generated on the surface of the photographic printing paper is prevented. effective.

Previously, the inventors of the present invention filed Japanese Patent Application No. 6-59087.
When a photographic emulsion paper is prepared by forming a photographic emulsion layer on the surface resin coating layer, the outermost surface resin coating layer of the surface resin coating layer is used to prevent the occurrence of rainbow stripes on the surface of the photographic printing paper. It has been disclosed that the blending ratio of the pigment blended in the resin coating layer is lower than the blending ratio of the pigment blended in the inner resin coating layer.

However, according to the present invention, since the pigment having a low refractive index as described above is blended, Japanese Patent Application No. 6-590 can be used.
Since it is not necessary to lower the amount of the pigment blended in the outermost resin coating layer as disclosed in No. 87, it is possible to increase the image sharpness when using photographic printing paper.
Furthermore, the surface resin coating layer has a laminated structure of two or more layers, and the outermost resin coating layer contains a pigment having a low refractive index and a pigment blended to improve the image sharpness, and the inner resin coating layer has an image. The same effect can be obtained by adding only a pigment to improve the sharpness.

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION The electron beam curable resin composition used for the surface resin coating layer on the side where the photographic emulsion layer of the photographic paper support of the present invention is formed is an electron beam curable resin which is a base resin. It is composed of a combination of a polar oligomer, a monomer used for dilution, various pigments, a tint adjusting agent and various additives. The electron beam curable oligomer usually has a high viscosity, and therefore, it is usually diluted with a monofunctional monomer or a polyfunctional monomer to adjust the viscosity before use. However, it does not matter whether the monomer is used alone or the oligomer is used alone.

The surface resin coating layer formed on the surface of the sheet-shaped substrate of the present invention on which the photographic emulsion layer is formed comprises an unsaturated organic compound which can be cured by electron beam irradiation and a pigment having a low refractive index. And a white pigment, and a cured product of an electron beam curable resin composition containing a composition containing other additives, if necessary, by electron beam irradiation.

The unsaturated organic compound which can be cured by an electron beam used in the present invention can be selected from the following compounds. (1) Aliphatic, alicyclic, and araliphatic 1 to 6-valent alcohol and polyalkylene glycol acrylate compounds, (2) aliphatic, alicyclic, and araliphatic 1 to 6 Acrylate compounds obtained by adding an alkylene oxide to a dihydric alcohol, (3) polyacryloylalkyl phosphoric acid esters, (4) a reaction product of a carboxylic acid, a polyol and acrylic acid,
(5) Reaction product of isocyanate, polyol and acrylic acid, (6) Reaction product of epoxy compound and acrylic acid, (7) Epoxy compound and polyol,
Reaction product with acrylic acid.

Specifically, as the electron beam-curable unsaturated organic compound, methyl acrylate, ethyl acrylate, butyl acrylate, lauryl acrylate, stearyl acrylate, N-vinylpyrrolidone,
Acryloylmorpholine, 2-ethylhexyl acrylate, 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl acrylate, 2-hydroxypropyl methacrylate,
2-hydroxybutyl acrylate, 2-hydroxybutyl methacrylate, tetrahydrofurfuryl acrylate, tetrahydrofurfuryl methacrylate, caprolactone-modified tetrahydrofurfuryl acrylate, cyclohexyl acrylate, cyclohexyl methacrylate, dicyclohexyl acrylate, isobornyl acrylate, isobornyl methacrylate, benzyl acrylate , Benzyl methacrylate, ethoxydiethylene glycol acrylate, methoxytriethylene glycol acrylate, methoxypropylene glycol acrylate, polyethylene glycol diacrylate, epichlorohydrin modified polyethylene glycol diacrylate, nonylphenoxy polyethylene glycol acrylate, Alkylene oxide-modified phenoxy acrylate, N, N-dimethylaminoethyl acrylate, N, N-dimethylaminoethyl methacrylate,
1,4-butanediol diacrylate-1,4-butanediol dimethacrylate, 1,6-hexanediol diacrylate, 1,6-hexanediol dimethacrylate, diethylene glycol diacrylate, tripropylene glycol diacrylate, trimethylolpropane tri Acrylate, ethylene oxide-modified trimethylolpropane triacrylate, propylene oxide-modified trimethylolpropane triacrylate, neopentyl glycol-modified trimethylolpropane diacrylate, pentaerythritol triacrylate, pentaerythritol tetraacrylate, dipentaerythritol tetraacrylate, dipenta Erythritol pentaacrylate, dipentaerythritol hexaacrylate , Caprolactone modified dipentaerythritol hexaacrylate, polyoxyethylene epichlorohydrin modified bisphenol A diacrylate, ethylene oxide modified bisphenol A diacrylate, propylene oxide modified bisphenol A diacrylate, neopentyl glycol diacrylate, hydroxybivalic acid ester neopentyl glycol diacrylate It is preferably selected from acrylates, ethylene oxide-modified phenoxyphosphoric acid acrylates, ethylene oxide-modified phthalic acid acrylates, polybutadiene acrylates, and tris (acryloxyethyl) isocyanurate.

In the surface resin coating layer of the present invention, a pigment having a refractive index of 1.8 or less, which is blended for the purpose of preventing a rainbow stripe pattern generated on the surface of a photographic printing paper, and image sharpness improvement. A white pigment having a refractive index higher than 1.8 is contained for the purpose. Further, when the surface resin coating layer is a laminate of two or more layers, the outermost resin coating layer has a refractive index of 1.8.
Each of the following pigments and at least one white pigment having a refractive index higher than 1.8 is contained, and the inner resin coating layer contains a white pigment blended for the purpose of improving image sharpness.
As the inorganic pigment blended for preventing light interference, silica, aluminum hydroxide, aluminum oxide, calcium carbonate, clay can be used, and barium sulfate, magnesium oxide, magnesium hydroxide and the like can also be used. Further, as the plastic pigment compounded for preventing light interference, either a thermoplastic resin or a thermosetting resin may be used, and polyethylene, polystyrene, polyvinyl chloride, urea resin, epoxy resin, urethane resin is used. It is possible, but it is preferable that it does not dissolve in the electron beam curable monomer or oligomer. Any of these pigments can be used as long as the refractive index is 1.8 or less. Titanium dioxide (anatase type or rutile type) is mainly used as a white pigment mixed with these pigments for the purpose of improving image sharpness, but zinc oxide can also be used.

The refractive index of the pigment in the present invention is 83 in the revised new edition handbook of pigments (published March 10, 1989, Seibundo Shinkosha).
It is a value measured by the Larsen oil immersion method described on page 84.

The pigment content of the surface resin coating layer or the outermost resin coating layer is preferably 30 to 80% by weight, and preferably 30 to 60% by weight based on the total solid weight of the surface resin coating layer or the outermost resin coating layer. % Is more preferable. Its content is 3
If it is less than 0% by weight, the sharpness of the obtained photographic image on the photographic paper is not sufficient, and if it exceeds 80% by weight, the flexibility of the obtained surface resin coating layer is lowered and film cracking occurs. As the pigment having a refractive index of 1.8 or less, which is mixed in the surface resin coating layer or the outermost resin coating layer to prevent light interference,
The total amount of the pigment blended in the electron beam curable resin composition forming the surface resin coating layer or the outermost resin coating layer is 20 to 20%.
80% by weight, preferably 20 to 60% by weight, and the other components include a pigment for improving image sharpness. If the amount of pigment added to prevent light interference is less than 20% by weight,
The effect of preventing light interference is not exhibited, and if it exceeds 80% by weight, sufficient image sharpness cannot be obtained.

To disperse the pigment compounded for preventing light interference and the white pigment compounded for improving sharpness in the electron beam curable unsaturated organic compound as described above, 3
A main roll mill (three roll mill), a two roll mill (two roll mill), a cowles dissolver, a homomixer, a sand grinder, a planetary mixer, an ultrasonic disperser and the like can be used.

The method for applying the electron beam curable resin composition to the surface of the sheet-like support is, for example, bar coating method, air doctor coating method, blade coating method, squeeze coating method, air knife coating method, roll coating method. Any of the gravure coating method, the transfer coating method and the like may be used. Further, for this purpose, a fountain coater or a slit die coater can be used.

In the support for photographic printing paper of the present invention, the total coating amount of the surface resin coating layer is 5 to 60 after curing.
It is preferably g / m ² , and more preferably 15 to
It is 50 g / m ² . If this coating amount is less than 5 g / m ² ,
The smoothness and hiding power of the obtained photographic printing paper support, the occurrence of rainbow stripes and the resolving power of the obtained photographic printing paper may be insufficient, and the coating amount exceeds 60 g / m ^2. When the number is large, the effect of the present invention is saturated, the resin coating layer becomes thick, and the cost becomes high. When the surface resin coating layer is a laminate of two or more layers, the coating amount of the outermost resin coating layer is preferably 0.5 to 15 g / m ² , more preferably 1 to 5 g / m ^2. Is.

When more than two surface resin coating layers are laminated, if the outermost resin coating layer of the surface resin coating layer is mixed with a pigment having a refractive index of 1.8 or less, a laminated structure is obtained. However, the effect of preventing the rainbow stripe pattern can be sufficiently exhibited.

In the present invention, the electron beam accelerator used for electron beam irradiation may be any of the Van de Graaff scanning system, the double scanning system and the curtain beam system, but a curtain beam which is relatively inexpensive and has a large output can be used. The system is advantageously used. The acceleration voltage at the time of electron beam irradiation is preferably 100 to 300 kV, and the absorbed dose is preferably 0.1 to 6 Mrad, and particularly preferably 0.2 to 4.0 Mrad.

The oxygen concentration in the atmosphere during electron beam irradiation is 1000 ppm or less, preferably 500 ppm or less. If the oxygen concentration is higher than 1000 ppm, the electron beam curable resin composition may have insufficient curing because the polymerization reaction may be hindered by the presence of oxygen. However, of course, there is no problem in reducing the oxygen concentration by using an inert gas for the purpose of suppressing ozone generation due to electron beam irradiation, or for the purpose of cooling a window that generates heat when the electron beam passes. Further, the type and concentration of the coexisting gas, the temperature and the humidity of the atmosphere are not particularly limited, and coexistence with an inert gas such as nitrogen gas or argon gas is allowed.

In the present invention, the backside resin coating layer is formed on the surface of the sheet-shaped substrate opposite to the surface on which the surface resin coating layer is formed. As the film-forming synthetic resin used to form the backside resin coating layer, use should be made of the polyolefin resins used in the production of conventional photographic paper supports, or the aforementioned electron beam-curable unsaturated organic compounds. Can be done.

In the present invention, the polyolefin resin for forming the backside resin coating layer is ethylene, α-
It can be selected from olefins such as homopolymers of propylene, copolymers of at least two of ethylene and α-olefins, and mixtures of at least two of these various polymers. Particularly preferred polyolefin resins are low density polyethylene, high density polyethylene, linear low density polyethylene, and mixtures thereof. The molecular weight of the polyolefin resin is not particularly limited, but one having a range of 20,000 to 200,000 is usually used.

The polyolefin resin, if necessary,
Small amounts of antioxidants and lubricants may be added. In order to form a back resin coating layer using a polyolefin resin, ordinary melt extrusion coating can be used.

As the electron beam-curable unsaturated organic compound for forming the backside resin coating layer, all the compounds used for forming the above-mentioned frontside resin coating layer can be used.
Further, the method of forming the back surface resin coating layer is the same as that of the above-described front surface resin coating layer.

The weight of the backside resin coating layer is not particularly limited, but it is generally preferably in the range of 10 to 40 g / m ² . In the present invention, the backside resin coating layer is provided for the purpose of preventing penetration of the developer into the support during development and preventing twisting and curling caused by contraction of the surface resin coating layer during electron beam irradiation.

The sheet-like base material used in the present invention is usually a base paper having a weight of 50 to 300 g / m ² and having a smooth surface, which is generally used for producing a photographic paper support.

As the base paper, any paper base generally formed from natural pulp can be used. As the natural pulp forming the paper substrate, generally, softwood pulp produced from fir tree, stalks, etc., hardwood pulp produced from maple, beech, poplar, etc., and those containing natural pulp as a main component such as coniferous hardwood mixed pulp. Widely used, kraft pulp,
Bleached chemical pulp such as sulfite pulp and soda pulp can be used. Further, the paper substrate may be blended with additives such as a sizing agent, a fixing agent, a paper strength enhancer, 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, an antistatic agent, etc. may be appropriately applied to the surface.

Further, the paper substrate may contain a magnesium compound such as magnesium oxide or magnesium hydroxide for the purpose of preventing fog that occurs during long-term storage when used as a photographic printing paper.

Further, in the present invention, there is no problem in using a plastic film or so-called synthetic paper as a sheet-shaped substrate. For example, a film formed by a melt extrusion method of a thermoplastic resin composition containing a polyolefin resin such as polypropylene resin or polyethylene resin can be used as the sheet-shaped substrate. Also, for plastic films used as sheet-like substrates and so-called synthetic paper, pigments such as clay, talc, kaolin, calcium carbonate, titanium dioxide and magnesium hydroxide, metal soaps such as zinc stearate,
One or more kinds of various surfactants and colored pigments may be contained.

[0038]

EXAMPLES Hereinafter, the structure and effects of the present invention will be described in more detail with reference to Examples, but the present invention is not limited to these embodiments. In the examples, "parts by weight" means
Represents parts by weight in terms of solid content.

Example 1 A paper substrate having a basis weight of 180 g / m ² was used as a sheet-like substrate, and one surface of the substrate was subjected to surface activation treatment by corona discharge, and then a polyethylene resin coating amount of 30 g was applied thereto. /
The resin was coated by the melt extrusion coating method so that the backside resin coating layer had a thickness of m ² .

Next, a coating composition (composition 1) for forming a surface resin coating layer having the composition shown below on the other surface of the paper substrate was mixed and dispersed for 1 hour with a paint conditioner and then cured using a wire bar. Later application amount is 25g /
It is coated so that it has a m ² of ² , and the oxygen concentration is 10
Acceleration voltage: 16 from the back of the paper substrate in an atmosphere of 0 ppm
The composition 1 was cured by irradiating it with an electron beam under the conditions of an absorbed dose of 2 Mrad at 5 kV to form a surface resin coating layer, to prepare a support for photographic printing paper.

Composition 1 component Composition urethane acrylate oligomer 30 parts by weight (trademark: Beamset 550B, manufactured by Arakawa Chemical Industry) trifunctional acrylate monomer (trademark: M-309, manufactured by Toagosei) 20 parts by weight titanium dioxide 40 parts by weight Part (Trademark: A-220, Ishihara Sangyo, Refractive index: 2.52) Aluminum hydroxide 10 parts by weight (Trademark: Heidilite H-42, Showa Denko, Refractive index: 1.57)

The surface of the surface resin coating layer of the obtained photographic printing paper support was subjected to corona discharge treatment and then coated with a 5% gelatin solution so that the coating amount after drying was 0.1 g / m ^2. To form a subbing layer, and then apply a black-and-white photographic emulsion (trademark: Art Emulsion, made by Fuji Photo Film Co., Ltd.) on the subbing layer so that the coating amount after drying is 6 g / m ² , and dry to photograph print. Paper was prepared, and the resolution and rainbow stripe pattern were evaluated using the obtained photographic printing paper. Table 1 shows the results.

The evaluation of the stripe pattern due to the resolution and interference of light was performed as follows. Resolution: Photographic paper is exposed using an MTF exposure device,
The resolution at a spatial frequency of 5 lines / mm was measured. A resolution of 60% or more is practical, but a resolution of less than 60% is not practical.

Rainbow stripe pattern: The rainbow stripe pattern on the surface of the photographic emulsion layer was visually evaluated. Evaluation was made on a three-point scale, in which the case where no rainbow stripe pattern was observed at all was 3 points, the case where a slight rainbow stripe pattern was observed was 2 points, and the case where it was very recognized was 1 point. 3 points are practical, but 2 points and 1 point are not practical.

Example 2 A support for photographic printing paper was prepared and evaluated in the same manner as in Example 1. However, the following composition 2 was used as the coating composition for forming the surface resin coating layer. Table 1 shows the evaluation results.

[0046] Composition 2 Ingredients Blend urethane acrylate oligomer 30 parts by weight (trademark: Beam Set 550B, Arakawa Chemical Industries, Ltd.) 3-functional acrylate monomer (trademark: M-309, manufactured by Toagosei) 20 parts by weight of titanium dioxide 25 wt Part (Trademark: A-220, Ishihara Sangyo, Refractive index: 2.52) Aluminum hydroxide 25 parts by weight (Trademark: Heidilite H-42, Showa Denko, Refractive index: 1.57)

Example 3 A support for photographic printing paper was prepared and evaluated in the same manner as in Example 1. However, the following composition 3 was used as the coating composition for forming the surface resin coating layer. Table 1 shows the evaluation results.

[0048] Composition 3 Ingredients Blend urethane acrylate oligomer 30 parts by weight (trademark: Beam Set 550B, Arakawa Chemical Industries, Ltd.) 3-functional acrylate monomer (trademark: M-309, manufactured by Toagosei) 20 parts by weight of titanium dioxide 10 wt Parts (Trademark: A-220, Ishihara Sangyo, Refractive index: 2.52) Aluminum hydroxide 40 parts by weight (Trademark: Heidilite H-42, Showa Denko, Refractive index: 1.57)

Example 4 In the same manner as in Example 1, an inner resin coating layer-forming coating composition (composition 4) having the following composition was painted on the other surface of the paper substrate on which the back resin coating layer was formed. After mixing and dispersing with a conditioner for 1 hour, coating was performed using a wire bar so that the coating amount after curing was 25 g / m ² , and an inner resin coating liquid layer was formed.

Composition 4 components Composition urethane acrylate oligomer 36 parts by weight (trademark: Beamset 550B, manufactured by Arakawa Chemical Industry) Bifunctional acrylate monomer (trademark: M-309, manufactured by Toagosei) 24 parts by weight Titanium dioxide 40 parts by weight Part (Trademark: A-220, Ishihara Sangyo, Refractive index: 2.52)

Separately from this, a coating composition (composition 5) for forming an outermost resin coating layer having the following composition was applied on the surface of a molding substrate made of a chromium-plated metal plate with a paint conditioner. After mixing and dispersing for 1 hour, coating was performed using a wire bar so that the coating amount after curing was 5 g / m ² to form an outermost resin coating liquid layer. Next, this outermost resin coating liquid layer was irradiated with an electron beam under the conditions of accelerating voltage: 165 kV and absorbed dose: 3 Mrad to cure the coating liquid layer to form an outermost resin coating layer.

Composition 5 components Composition pentaerythritol tetraacrylate 70 parts by weight (Trademark: Beamset 710, manufactured by Arakawa Chemical Industries) Titanium dioxide 10 parts by weight (Trademark: A-220, Ishihara Sangyo, Refractive index: 2. 52) 20 parts by weight of aluminum hydroxide (trademark: Hydilite H-42, manufactured by Showa Denko, refractive index: 1.57)

Next, the outermost resin coating layer and the inner resin coating liquid layer on the paper base are superposed on a metal plate for molding, and this laminate is subjected to an acceleration voltage of 175 from the back of the paper base.
It was obtained by irradiating an electron beam under the conditions of kV, absorbed dose: 2 Mrad to cure the inner resin coating liquid layer, and at the same time, bonding the outermost resin coating layer and the inner resin coating liquid layer to integrate them. The laminated body was peeled off from the surface of the metal plate to form a surface resin coating layer, to prepare a support for photographic printing paper. The results of the same evaluations as in Example 1 are shown in Table 1.

Example 5 A support for photographic printing paper was prepared and evaluated in the same manner as in Example 4. However, the following composition 6 was used as the coating composition for forming the outermost resin coating layer. Table 1 shows the evaluation results.

Composition 6 components Composition pentaerythritol tetraacrylate 60 parts by weight (Trademark: Beamset 710, manufactured by Arakawa Chemical Industries) Titanium dioxide 32 parts by weight (Trademark: A-220, Ishihara Sangyo, Refractive index: 2. 52) Aluminum hydroxide 8 parts by weight (trademark: Heidilite H-42, manufactured by Showa Denko, refractive index: 1.57)

Example 6 A support for photographic printing paper was prepared and evaluated in the same manner as in Example 4. However, the following composition 7 was used as the coating composition for forming the outermost resin coating layer. Table 1 shows the evaluation results.

Composition 7 components Composition pentaerythritol tetraacrylate 60 parts by weight (Trademark: Beamset 710, manufactured by Arakawa Chemical Industry) Titanium dioxide 20 parts by weight (Trademark: A-220, Ishihara Sangyo, Refractive index: 2. 52) 20 parts by weight of aluminum hydroxide (trademark: Hydilite H-42, manufactured by Showa Denko, refractive index: 1.57)

Example 7 A support for photographic printing paper was prepared and evaluated in the same manner as in Example 4. However, the following composition 8 was used as the coating composition for forming the outermost resin coating layer. Table 1 shows the evaluation results.

Composition 8 components Composition pentaerythritol tetraacrylate 60 parts by weight (Trademark: Beamset 710, manufactured by Arakawa Chemical Industry) Titanium dioxide 8 parts by weight (Trademark: A-220, Ishihara Sangyo, Refractive index: 2. 52) Aluminum hydroxide 32 parts by weight (trademark: Hydilite H-42, manufactured by Showa Denko, refractive index: 1.57)

Example 8 A support for photographic printing paper was prepared and evaluated in the same manner as in Example 4. However, the following composition 9 was used as the coating composition for forming the outermost resin coating layer. Table 1 shows the evaluation results.

[0061] Composition 9 Ingredients Blend pentaerythritol tetraacrylate 50 parts by weight (trademark: Beam Set 710, Arakawa Chemical Industries, Ltd.) Titanium dioxide 30 parts by weight (trademark: A-220, manufactured by Ishihara Sangyo Kaisha, refractive index: 2. 52) 20 parts by weight of aluminum hydroxide (trademark: Hydilite H-42, manufactured by Showa Denko, refractive index: 1.57)

Example 9 A support for photographic printing paper was prepared and evaluated in the same manner as in Example 4. However, the following composition 10 was used as the coating composition for forming the outermost resin coating layer. Table 1 shows the evaluation results.
Shown in

Composition 10 components Composition pentaerythritol tetraacrylate 40 parts by weight (Trademark: Beamset 710, manufactured by Arakawa Chemical Industry) Titanium dioxide 40 parts by weight (Trademark: A-220, Ishihara Sangyo, Refractive index: 2. 52) 20 parts by weight of aluminum hydroxide (trademark: Hydilite H-42, manufactured by Showa Denko, refractive index: 1.57)

Example 10 A support for photographic printing paper was prepared and evaluated in the same manner as in Example 4. However, the following composition 11 was used as the coating composition for forming the outermost resin coating layer. Table 1 shows the evaluation results.
Shown in

[0065] Composition 11 Ingredients Blend pentaerythritol tetraacrylate 20 parts by weight (trademark: Beam Set 710, Arakawa Chemical Industries, Ltd.) Titanium dioxide 60 parts by weight (trademark: A-220, manufactured by Ishihara Sangyo Kaisha, refractive index: 2. 52) 20 parts by weight of aluminum hydroxide (trademark: Hydilite H-42, manufactured by Showa Denko, refractive index: 1.57)

Example 11 A support for photographic printing paper was prepared and evaluated in the same manner as in Example 8. However, the following composition 12 was used as the coating composition for forming the inner resin coating layer, and composition 9 was used as the coating composition for forming the outermost resin coating layer. Table 1 shows the evaluation results.

Composition 12 components Composition urethane acrylate oligomer 30 parts by weight (trademark: Beamset 550B, manufactured by Arakawa Chemical Industry) Bifunctional acrylate monomer (trademark: M-220, manufactured by Toagosei) 20 parts by weight Titanium dioxide 50 parts by weight Part (Trademark: A-220, Ishihara Sangyo, Refractive index: 2.52)

Example 12 A support for photographic printing paper was prepared and evaluated in the same manner as in Example 8. However, the following composition 13 was used as the coating composition for forming the inner resin coating layer, and composition 9 was used as the coating composition for forming the outermost resin coating layer. Table 1 shows the evaluation results.

Composition 13 components Composition urethane acrylate oligomer 24 parts by weight (trademark: Beamset 550B, manufactured by Arakawa Chemical Industry) Bifunctional acrylate monomer (trademark: M-220, manufactured by Toagosei) 16 parts by weight Titanium dioxide 60 parts by weight Part (Trademark: A-220, Ishihara Sangyo, Refractive index: 2.52)

Example 13 A photographic printing paper support was prepared and evaluated in the same manner as in Example 4. However, the following composition 14 was used as the coating composition for forming the outermost resin coating layer. Table 1 shows the evaluation results.
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Composition 14 Composition Pentaerythritol tetraacrylate 50 parts by weight (Trademark: Beamset 710, manufactured by Arakawa Chemical Industries) Titanium dioxide 30 parts by weight (Trademark: A-220, Ishihara Sangyo, Refractive index: 2. 52) Clay 20 parts by weight (trademark: UW-90, manufactured by ENGELHARD, refractive index: 1.56)

Example 14 A support for photographic printing paper was prepared and evaluated in the same manner as in Example 4. However, the following composition 15 was used as the coating composition for forming the outermost resin coating layer. Table 1 shows the evaluation results.
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[0073] The composition 15 Ingredients Blend pentaerythritol tetraacrylate 50 parts by weight (trademark: Beam Set 710, Arakawa Chemical Industries, Ltd.) Titanium dioxide 30 parts by weight (trademark: A-220, manufactured by Ishihara Sangyo Kaisha, refractive index: 2. 52) Calcium carbonate 20 parts by weight (trademark: Brilliant-15, made of Shiraishi calcium, refractive index: 1.57)

Example 15 A support for photographic printing paper was prepared and evaluated in the same manner as in Example 4. However, the following composition 16 was used as the coating composition for forming the outermost resin coating layer. Table 1 shows the evaluation results.
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Composition 16 components Composition pentaerythritol tetraacrylate 50 parts by weight (Trademark: Beamset 710, manufactured by Arakawa Chemical Industry) Titanium dioxide 30 parts by weight (Trademark: A-220, Ishihara Sangyo, Refractive index: 2. 52) Silica 20 parts by weight (Trademark: Mizukasil P-527, manufactured by Mizusawa Chemical Industry Co., Ltd., refractive index: 1.44)

Example 16 A support for photographic printing paper was prepared and evaluated in the same manner as in Example 4. However, the following composition 17 was used as the coating composition for forming the outermost resin coating layer. Table 1 shows the evaluation results.
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Composition 17 Composition Pentaerythritol tetraacrylate 50 parts by weight (trademark: Beamset 710, manufactured by Arakawa Chemical Industry) Titanium dioxide 30 parts by weight (trademark: A-220, Ishihara Sangyo, Refractive index: 2. 52) Aluminum oxide 20 parts by weight (trademark: alumina A-50-N, manufactured by Showa Denko, refractive index: 1.76)

Example 17 A support for photographic printing paper was prepared and evaluated in the same manner as in Example 4. However, the following composition 18 was used as the coating composition for forming the outermost resin coating layer. Table 1 shows the evaluation results.
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[0079] The composition 18 Ingredients Blend pentaerythritol tetraacrylate 50 parts by weight (trademark: Beam Set 710, Arakawa Chemical Industries, Ltd.) Titanium dioxide 30 parts by weight (trademark: A-220, manufactured by Ishihara Sangyo Kaisha, refractive index: 2. 52) 20 parts by weight of plastic pigment (trademark: Eupearl C-122, manufactured by Mitsui Toatsu Chemicals, refractive index: 1.65)

Comparative Example 1 A support for photographic printing paper was prepared and evaluated in the same manner as in Example 4. However, the following composition 19 was used as the coating composition for forming the outermost resin coating layer. Table 1 shows the evaluation results.
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Composition 19 Composition Pentaerythritol tetraacrylate 80 parts by weight (trademark: Beamset 710, manufactured by Arakawa Chemical Industry) Titanium dioxide 20 parts by weight (trademark: A-220, Ishihara Sangyo, Refractive index: 2. 52)

Comparative Example 2 A support for photographic printing paper was prepared and evaluated in the same manner as in Example 4. However, the following composition 20 was used as the coating composition for forming the outermost resin coating layer. Table 1 shows the evaluation results.
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Composition 20 components Composition pentaerythritol tetraacrylate 70 parts by weight (Trademark: Beamset 710, manufactured by Arakawa Chemical Industry) Titanium dioxide 30 parts by weight (Trademark: A-220, Ishihara Sangyo, Refractive index: 2. 52)

Comparative Example 3 A support for photographic printing paper was prepared and evaluated in the same manner as in Example 4. However, the following composition 21 was used as the coating composition for forming the outermost resin coating layer. Table 1 shows the evaluation results.
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Composition 21 Composition Component pentaerythritol tetraacrylate 50 parts by weight (Trademark: Beamset 710, manufactured by Arakawa Chemical Industry) Titanium dioxide 50 parts by weight (Trademark: A-220, Ishihara Sangyo, Refractive index: 2. 52)

Comparative Example 4 A support for photographic printing paper was prepared and evaluated in the same manner as in Example 4. However, the following composition 22 was used as the coating composition for forming the outermost resin coating layer. Table 1 shows the evaluation results.
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The compositions 22 Ingredients Blend pentaerythritol tetraacrylate 50 parts by weight (trademark: Beam Set 710, Arakawa Chemical Industries, Ltd.) Titanium dioxide 30 parts by weight (trademark: A-220, manufactured by Ishihara Sangyo Kaisha, refractive index: 2. 52) Zinc oxide 20 parts by weight (Trademark: Zinc Hua No. 1, manufactured by Mitsui Mining & Smelting Co., refraction index: 2.0)

[0088]

[Table 1]

From Examples 1 to 17, when the surface resin coating layer or the outermost resin coating layer contains a pigment having a refractive index of 1.8 or less in an amount of 20 to 80% by weight of the total pigment content, the resolution is improved. A support for photographic printing paper is obtained which is as high as 60% or more and has no rainbow stripe pattern.

[0090]

EFFECTS OF THE INVENTION The present invention has a problem that a support for photographic printing paper provided with an electron beam curable resin coating layer has, namely,
When a photographic printing paper is prepared by providing a photographic emulsion layer on the surface resin coating layer, the rainbow stripe pattern generated on the surface of the photographic emulsion layer can be greatly reduced, and a photographic printing paper with good image sharpness can be obtained. The present invention provides a support for photographic printing paper that can be produced, and is extremely effective in practice.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code Agency reference number FI Technical display location D21H 19/38 D21H 1/22 B

Claims (3)

[Claims] 1. An electron of a coating composition comprising a sheet-shaped base material and an unsaturated organic compound which is formed on one surface of the sheet-shaped base material and is curable by electron beam irradiation and a pigment as main components. In a support for photographic printing paper having a surface resin coating layer composed of a line-cured body and a back surface resin coating layer formed on the other surface of the sheet-shaped substrate and containing a film-forming synthetic resin as a main component The support for photographic printing paper, wherein the surface resin coating layer contains titanium dioxide, and the content of pigments having a refractive index of 1.8 or less is 20 to 80% by weight in all pigments. 2. An electron of a coating composition comprising a sheet-like base material and an unsaturated organic compound which is formed on one surface of the sheet-like base material and is curable by electron beam irradiation and a pigment as main components. In a support for photographic printing paper having a surface resin coating layer composed of a line-cured body and a back surface resin coating layer formed on the other surface of the sheet-shaped substrate and containing a film-forming synthetic resin as a main component , The surface resin coating layer,
It is composed of a laminate of at least two layers including an inner resin coating layer adjacent to the sheet-shaped substrate and an outermost resin coating layer arranged on the outermost side, and the outermost resin coating layer contains titanium dioxide, and A support for photographic printing paper, characterized in that the content of a pigment having a refractive index of 1.8 or less is contained in an amount of 20 to 80% by weight based on the total amount of the pigment. 3. The pigment having a refractive index of 1.8 or less, which is mixed in the surface resin coating layer, is an inorganic pigment such as silica, aluminum hydroxide, aluminum oxide, calcium carbonate, clay, and a plastic pigment such as polyethylene or polystyrene. The support for photographic printing paper according to claim 1 or 2, which is at least one selected from the group consisting of polyvinyl chloride, urea resin, epoxy resin and urethane resin.