JPH08334862A - Substrate for photographic printing paper - Google Patents

Abstract

PURPOSE: To provide a substrate ensuring superior sharpness of an image, maintaining the surface properties of a coating layer of an electron beam-curable resin under various conditions of humidity and having superior photographic characteristics. CONSTITUTION: A front resin coating layer made of a cured body of an electron beam-curable resin compsn. is formed on one side of a paper base by 10-40g/m<2> coating weight and a rear resin coating layer contg. a film forming synthetic resin is formed on the other side. The compsn. contains an electron beam-curable unsatd. org. compd. represented by the formula and other unsatd. org. compd. so that the weight ratio is regulated to 20:80 to 70:30. In the formula, R is tricyclo[5.2.1.0<2.6> ]decanylene which may have a substituent or 1,3-dioxy which may have a substituent.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a support for photographic printing paper. More specifically, the present invention is a photographic print having a surface resin coating layer composed of a cured product of a composition containing an unsaturated organic compound curable by electron beam irradiation (hereinafter referred to as electron beam curable unsaturated organic compound). A photographic printing paper that is related to a paper support, has good image sharpness, does not have wrinkle-like wrinkles on the surface, has good surface properties, and has little change in surface condition due to humidity changes in the atmosphere. The present invention relates to a photographic printing paper support.

[0002]

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

An inorganic white pigment such as titanium dioxide is mixed into 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, there is an inconvenience that the pigment content in the coating layer cannot be increased to a level sufficient to improve the hiding power or the resolution. Generally speaking, when titanium dioxide is used as the inorganic white pigment, it is difficult to add it in an amount of about 20% by weight or more for the above reason. 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, Japanese Patent Publication No. 60-17104, Japanese Patent Publication No. 60-17105, and Japanese Unexamined Patent Publication No. 57-4.
In Japanese Patent Application Laid-Open No. 9946 and Japanese Patent Application Laid-Open No. 5-119431, a resin composition that can be cured by electron beam irradiation (hereinafter referred to as electron beam curable resin composition) is applied to a support, and this is irradiated with electron beam. A photographic paper support having an electron beam-curable resin coating layer which has been cured by applying the above has been proposed.
According to this method, it is not necessary to heat the electron beam curable resin composition to a high temperature when forming the electron beam curable resin coating layer,
It is also possible to increase the pigment content up to 20-80% 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, and since heating and cooling are not performed in the manufacturing process, the photographic printing paper is The surface of the paper is excellent.

However, a photographic printing paper produced by coating a photographic photosensitive layer on an electron beam-curable resin coating layer cured by electron beam irradiation causes expansion and contraction of the paper base due to environmental changes, especially humidity changes, and There is a problem that the surface properties of the wire-cured resin coating layer deteriorate. When the developed photographic printing paper is left in a high-humidity or low-humidity environment, wrinkle-like wrinkles gradually appear on the surface of the electron beam curable resin coating layer, and as a photographic printing paper seeking high surface properties, There was a problem that markedly reduced the commercial value.

[0006]

DISCLOSURE OF THE INVENTION The present invention solves the above-mentioned problems of the prior art, is excellent in image sharpness, and maintains the surface property of the electron beam curing resin coating layer under various humidity conditions. Another object of the present invention is to provide a photographic paper support suitable for producing a photographic paper having excellent photographic characteristics.

[0007]

A photographic printing paper support of the present invention is formed on one surface of a paper substrate containing natural pulp as a main component and said paper substrate, and cured by electron beam irradiation. Surface resin coating layer formed of a cured product of a composition containing a unsaturated organic compound as a main component, and a back resin coating layer formed on the other surface of the paper substrate and containing a film-forming synthetic resin as a main component. And the surface resin coating layer is represented by the following formula (1) at least one unsaturated organic compound curable by electron beam irradiation, unsaturated organic compound of formula (1) Formed by an electron beam cured product of the composition containing the unsaturated organic compound other than the formula (1) in a weight ratio of 20/80 to 70/30,
The coating amount of the surface resin coating layer is 10 to 40 g / m ² .

[0008]

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[In the formula (1), R is a tricyclo [5.2.1.0 ^2.6 ] decanylene group, a tricyclo [5.2.1.0 ^2.6 ] decanylene group having a substituent, 1,
It is a 3-dioxy group or a 1,3-dioxy group having a substituent. ]

Further, the surface resin coating layer in the present invention has a laminated structure of at least two layers including an inner resin coating layer adjacent to the paper base and an outermost resin coating layer arranged on the outermost side. It is necessary that at least one of the coating layers constituting the resin coating layer is made of the electron beam cured product.

The present inventors have proposed an electron beam curable resin composition
A photographic print produced from a support obtained by forming a coating layer of an electron beam-curable resin, which is coated on at least one surface of a paper base containing natural pulp as a main component, and is cured by irradiating the paper with an electron beam. The surface properties of paper deteriorate due to environmental changes, especially humidity changes. As a result of diligent research on the cause, it was found that the cause of the deterioration of the surface property was expansion and contraction due to the change in water content of the paper substrate.

That is, in general, many coating films formed by using an electron beam-curable resin composition as a main component allow water vapor to pass through well, and therefore the paper substrate absorbs moisture under high humidity to expand.
Under low humidity, the paper substrate is dehumidified and shrinks, so that the surface resin coating layer and the photographic emulsion layer are deformed to deteriorate the surface property.

In order to solve this problem, the expansion and contraction of the paper base due to moisture absorption and dehumidification due to environmental changes, especially humidity changes, should be suppressed, so that the moisture permeability of the coating layers on both sides of the paper base should be kept low. . Since the backside resin coating layer does not require image sharpness and high gloss, it is possible to arbitrarily select a commonly used film-forming synthetic resin having low moisture permeability, such as polyethylene, which is substantially an electron beam curable resin composition. It is important to reduce the water vapor transmission rate of the surface resin coating layer formed from the object.

Therefore, the moisture permeability of the front surface resin coating layer and the back surface resin coating layer is 50 [g / m ² · 24 hours] (25 ° C.,
90% RH) or less, preferably 40 [g / m ² · 24 hours] (25 ° C., 90% RH) or less. If the photographic printing paper is left in an environment where the humidity changes if it is larger than this value, the paper substrate absorbs and dehumidifies in a short time, causing wrinkle-like wrinkles on the surface and deteriorating the surface property in a short time. I will end up.

In order to keep the moisture permeability of the surface resin coating layer formed from the electron beam curable resin composition low, it is effective to increase the crosslink density, and therefore the electron beam curable resin composition is cured. To increase the electron beam irradiation dose, increase the amount of the multifunctional electron beam-curable unsaturated organic compound monomer or oligomer compounded, and adjust the electron beam-curable unsaturated organic compound having a relatively small molecular weight. It is possible to suppress the water vapor transmission rate by means such as adding a large amount. However, each of these methods not only deteriorates the flexibility of the coating film, but also increases fog during long-term storage when used as a photographic printing paper when the irradiation dose of electron beam is increased. It also has the drawbacks that the paper substrate is discolored yellow by the impact of electron beam irradiation, and the paper strength and paper quality are deteriorated.

Further, adding a large amount of a hydrophobic electron beam-curable unsaturated organic compound is also effective in suppressing the moisture permeability, but since polar bonds such as hydrogen bonds are reduced, the paper substrate It also has the drawback that the adhesion to the surface of the resin is deteriorated and the flexibility of the surface resin coating layer is lost.

As a result of various studies on this point, the present inventors have found that, as in Japanese Patent Application No. 7-42682, by blending a monofunctional unsaturated organic compound having a specific structure with a surface resin coating layer, A method has been found for achieving both low humidity and maintaining flexibility of the surface resin coating layer, but it is required to achieve even lower moisture permeability and suppress deterioration of surface properties.

As a result of various studies on this point, the present inventors have found that, as mentioned above, the electron beam curable resin composition which is formed on at least one surface of the paper substrate is cured by electron beam irradiation. The surface resin coating layer thus formed has at least one kind of unsaturated organic compound of formula (1), and contains an unsaturated organic compound of formula (1) and an unsaturated organic compound other than formula (1). It was found that these problems can be effectively solved by blending in a weight ratio of 20/80 to 70/30, preferably 30/70 to 60/40. That is, by improving the low moisture permeability of the surface resin coating layer, it has succeeded in simultaneously preventing the deterioration of the surface property due to the humidity change of the photographic printing paper and maintaining the flexibility.

The electron beam-curable unsaturated organic compound of the formula (1) of the present invention may be blended with a monomer or oligomer of the electron beam-curable unsaturated organic compound other than the formula (1), but It is necessary that the content of the unsaturated organic compound of the formula (1) is at least 20% by weight or more, and if it is less than 20% by weight, the viscosity of the coating material becomes too high and the moisture permeability becomes large. When the content of the unsaturated organic compound of the formula (1) is more than 70% by weight, the surface resin coating layer after curing becomes too hard and brittle, which adversely affects flexibility.

The electron beam-curable unsaturated organic compound used in the present invention can be selected from the following compounds, for example.

[0021]

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[0022]

[Chemical 4]

In the present invention, the electron beam curable unsaturated organic compound monomer or oligomer used together with the electron beam curable unsaturated organic compound of the formula (1) used in the surface resin coating layer is a crosslinked resin coating. As long as it can form a layer, it may be a monomer alone, an oligomer alone, or a mixture thereof. Further, the type of the unsaturated organic compound is not particularly limited, but Japanese Patent Application No.
It is more effective to use the monofunctional monomer shown in No. 42682 together. It is not necessary to increase the crosslinking density so far as the content ratio for obtaining the moisture vapor transmission rate of the surface resin coating layer of the present invention and the application amount are in the ranges, and an electron beam curable unsaturated organic compound having good flexibility can be selected. it can.

In the surface resin coating layer of the support for photographic printing paper of the present invention, 50 [g / m ² · 24 hours] (25 ° C.,
In order to achieve a water vapor transmission rate of 90% RH) or less, the unsaturated organic compound of the formula (1) is used in an amount of 20 to 70% of the total amount of the electron beam-curable unsaturated organic compound regardless of which coating method is adopted.
% By weight, and the coating amount after curing of the surface resin coating layer is 10 to 40 g / m ² , preferably 15 to 30 g / m ² , which prevents deterioration of surface property due to humidity change and provides flexibility. The effect of holding is obtained. Here, the coating amount is 10 g /
When it is less than m ² , the water vapor transmission rate becomes large, the surface property is deteriorated due to the humidity change of the photographic printing paper, and the smoothness, hiding power and resolution as the support for the photographic printing paper are not maintained.
On the other hand, if the coating amount is more than 40 g / m ² , the electron beam curable unsaturated organic compound may be uncured and the cost may increase.

Whichever coating method is used to form the coating liquid layer of the electron beam curable resin composition, the coating liquid layer can be divided into two or more layers so that the coating method can be freely applied in a plurality of coatings. The degree of application and the coating property are improved, and each layer can be given a unique function.

In the case where the surface resin coating layer has a laminated structure of two or more layers including at least an inner resin coating layer adjacent to the paper substrate and an outermost outer resin coating layer, the surface At least one of the resin coating layers is a layer having a low water vapor transmission rate, which is composed of an electron beam curable resin composition in which the unsaturated organic compound of the formula (1) is contained in an amount of 20 to 70% by weight based on the whole electron beam curable unsaturated organic compound. By forming one or more layers, it is possible to prevent deterioration of surface properties due to changes in humidity.

The electron beam curable resin composition for forming a surface resin coating layer on one surface of a paper substrate according to the present invention contains a mixture of an electron beam curable unsaturated organic compound and a white pigment as a main component and is required. Depending on the monomer or oligomer of the unsaturated organic compound, a coupling agent, a surfactant, a polymerization inhibitor,
And additives such as antioxidants and dyes.

The monomer or oligomer of the electron beam-curable unsaturated organic compound used for forming the surface resin coating layer of the present invention is not particularly limited by the number of functional groups or the like, but imparts flexibility. For this reason, compounds having a functionality of 4 or less that give a low crosslink density are particularly advantageously used for the purposes of the invention. For example, it can be selected from the following compounds. (1) Aliphatic, alicyclic, or araliphatic alcohol or polyalkylene glycol acrylate compounds. (2) Acrylate compounds of aliphatic, alicyclic, and araliphatic compounds obtained by adding alkylene oxide to alcohol. (3) Polyacryloyl alkyl phosphates. (4) Reaction product of polybasic acid, polyol, and acrylic acid. (5) A reaction product of an isocyanate, a polyol, and acrylic acid. (6) A reaction product of an epoxy compound and acrylic acid. (7) A reaction product of an epoxy compound, a 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, caprolactane modified tetrahydrofurfuryl acrylate, tris (acryloxyethyl) isocyanurate, trimethylolpropane triacrylate, pentaerythritol triacrylate,
Examples thereof include pentaerythritol tetraacrylate, polyethylene glycol diacrylate, 1,4-butadiene diol diacrylate, neopentyl glycol diacrylate, and neopentyl glycol-modified trimethylolpropane diacrylate. These compounds can be used in combination with at least one kind of the electron beam curable unsaturated organic compound of the formula (1).

The surface resin coating layer of the present invention preferably contains a white pigment for the purpose of improving the image sharpness of a photographic printing paper. Further, other additives can be contained if necessary.

Titanium dioxide (anatase type and rutile type) is mainly used as the white pigment, and in addition to this, barium sulfate, calcium carbonate, aluminum oxide, zinc oxide, magnesium oxide, magnesium hydroxide and the like are among others. Can also be used.

The content of the white pigment is preferably 20 to 60% by weight of the total solid content of the surface resin coating layer.
If the content is less than 20% by weight, the sharpness of the obtained photographic image on the photographic printing paper may not be sufficient, and if it exceeds 60% by weight, the electron beam curable resin composition becomes highly viscous and uniform. The surface resin coating layer was not obtained and the moisture vapor transmission rate was 50 [g / m ² · 24 hours] (25 ° C, 90% R
H), resulting in reduced flexibility and further film cracking.

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.

In the present invention, the surface resin coating layer can be advantageously used by the method described in JP-A-5-93984. That is, an inner resin coating layer is formed by applying a coating liquid composed of an electron beam curable resin composition on a paper substrate, and then separately formed on the peripheral surface of a metal cylindrical rotary body or a molding surface such as a plastic film surface. A coating liquid composed of an electron beam curable resin composition is applied and cured to form an outermost resin coating layer, and then an outermost resin coating layer and an inner resin coating layer are superposed on the molding surface, and an electron It is a method of irradiating a ray to cure and adhering, and peeling the obtained sheet-shaped laminate from the molding surface.

Examples of the method for applying the electron beam curable resin composition to the molding surface or the surface of the paper substrate include bar coating, blade coating, squeeze coating, air knife coating, roll coating, gravure coating and the like. Any of the transfer coating method and the like may be used. Further, as a method for applying the electron beam curable resin composition, a fountain coater or a slit die coater can be used. Especially when using the surface of a metal cylindrical rotating body as a molding surface, the roll coating method or offset gravure coating method using a rubber roll is used to prevent scratches on the molding surface. Fountain coaters and slit die coaters of the type are advantageously used.

The electron beam accelerator used for electron beam irradiation is not particularly limited in its method, and for example, an electron beam irradiation device such as a Van de Graaff scanning system, a double scanning system, a curtain beam system, or the like can be used. However, among these, the curtain beam system, which is relatively inexpensive and has a large output, is effectively used. The accelerating voltage at the time of electron beam irradiation is not limited, but generally 100 to 300 KV is preferable. The absorbed dose is preferably 0.1 to 6 Mrad, more 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 curing of the electron beam curable resin composition may be insufficient. When curing by electron beam irradiation in a state where the coating liquid layer of the electron beam curable resin composition is cast with a metal cylindrical rotating body or a polyester film,
The coating liquid layer of the electron beam curable resin composition does not come into direct contact with air during electron beam irradiation, and therefore it is not necessary to particularly reduce the oxygen concentration in the atmosphere during electron beam irradiation.
Of course, there is no problem in using an inert gas such as nitrogen gas or argon gas for the purpose of suppressing ozone generation due to electron beam irradiation or for the purpose of cooling windows that generate heat when the electron beam passes. .

The film-forming synthetic resin used for forming the backside resin coating layer of the present invention has a moisture permeability of 5
It may be 0 [g / m ² · 24 hours] (25 ° C., 90% RH) or less, and may be a polyolefin resin used for producing a conventional photographic paper support, or the electron beam curable resin composition described above. Etc. can be used.

As the polyolefin resin for forming the backside resin coating layer, homopolymers of ethylene, α-olefins such as propylene, at least two copolymers of the above-mentioned olefins, and various kinds of these polymers can be used. 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 thereof. 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 antioxidant and 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 from an electron beam curable resin composition. To do this,
An electron beam curable unsaturated organic compound having a low moisture permeability used for forming the surface resin coating layer can be used. Further, the method for forming the backside resin coating layer may be a multilayer structure as in the case of the above-mentioned frontside resin coating layer. The coating amount 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 .

As the paper substrate used in the present invention, one having a basis weight of 50 to 300 g / m ² and a smooth surface is usually used. The paper substrate can be selected from all those generally used for a photographic printing paper support. As the natural pulp forming the paper substrate, generally,
Widely used are those mainly composed of softwood pulp, hardwood pulp, mixed softwood and hardwood pulp. Further, the paper substrate may contain a filler.

When a photographic printing paper is produced from the support of the present invention, the magnesium hydroxide, magnesium oxide and magnesium salt described in JP-A-4-234754 are used for the purpose of preventing fog which occurs during long-term storage. It is effective to include a magnesium compound such as 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 for papermaking. In addition, surface sizing agent, surface paper strength agent, pigment,
A dye, an antistatic agent or the like may be appropriately applied by a method such as a size press.

[0043]

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

Example 1 A paper substrate 1 (for moisture permeability measurement) having a basis weight of 180 g / m ² and a back surface of this paper substrate were subjected to a surface activation treatment by corona discharge, and a low density polyethylene (having a density of 0). .918 g
/ Cm ³ , 50 parts by weight of melt index 4 g / 10 minutes and high density polyethylene (density 0.964 g / cm ³ ,
A melt extrusion coating of a polyethylene resin mixed with 50 parts by weight of a melt index (20 g / 10 min) was performed, and a paper substrate 2 (for evaluating surface properties and flexibility) formed with a back resin coating layer having a coating amount of 25 g / m ² was formed. Create, 20 ℃, 65% R
The humidity was adjusted to H.

Separately, an electron beam-curable unsaturated organic compound-white pigment mixture composition (composition 1) for a surface resin coating layer having the composition shown below was used for 1 hour with a paint conditioner. It was prepared by mixing and dispersing.

Composition 1 Composition Blend Amount Tricyclodecanylenediacrylate 30 parts by weight (Trademark: KAYARAD R684 Nippon Kayaku Co., Ltd., formula (8)) Polyester acrylate 30 parts by weight (Trademark: Aronix M7100 Toagosei Kagaku Kogyo Co., Ltd.) Made) Titanium dioxide 40 parts by weight (Trademark: Taipek A-220 manufactured by Ishihara Sangyo Co., Ltd.)

The above composition 1 was added to paper base 1 and paper base 2
On the surface of, using a wire bar so that the coating amount after curing will be 15 g / m ² , it is laminated with the polyester film used as the molding surface, and the coating liquid layer is accelerated from the back of the polyester film. Voltage: 175K
V, absorbed dose: irradiating with an electron beam under the condition of 2 Mrad,
After the coating liquid layer was cured, the polyester film was peeled off to prepare a sample for measuring moisture permeability and a sample for evaluating surface property and flexibility.

In order to evaluate the water vapor permeability of the support for photographic printing paper, at 25 ° C. according to JIS Z 0208 (1976 version) “Moisture vapor permeable packaging material moisture permeability test method (cup method)”.
The moisture permeability was measured using the moisture permeability measurement sample obtained from the paper substrate 1 under the condition of 90% RH, and the moisture permeability of the surface resin coating layer was calculated by the following mathematical formula (1). 1 / (water vapor transmission rate of surface resin coating layer) = 1 / (water vapor transmission rate of sample for moisture vapor transmission measurement) -1 / (water vapor transmission rate of paper substrate 1) (1)

In order to evaluate the surface properties of the support for photographic printing paper, the samples for evaluation of surface properties and flexibility obtained from the paper base 2 were used, based on JIS K 7105 "Plastic optical property test method". 12 at 20 ℃ and 65% RH
The humidity was adjusted for time, and the image clarity was measured using a 2 mm comb.
Then, the humidity was adjusted at 20 ° C. and 85% RH for 48 hours, the image sharpness was measured using a 2 mm comb after the humidity adjustment, and the change rate of the image sharpness before and after the humidity adjustment was calculated by the following mathematical expression (2). . (Change rate of image sharpness) = (Image sharpness after humidity adjustment) / (Image sharpness before humidity adjustment) (2)

If the rate of change in image clarity is 0.85 or more, there is no practical problem, but if it is less than 0.85, deterioration of surface properties due to changes in environmental humidity becomes a problem.

The flexibility was evaluated by using the sample for evaluating the surface property and the flexibility obtained from the paper base 2 with the surface resin coating layer on the outside and winding the round bar having a diameter of 0.2 cm, and cracking. The condition was visually evaluated. Evaluation was made on a three-point scale, in which no cracks were found at all, 3 points were slightly cracked at 2 points, and cracked pieces were at 1 point. Three and two points are practical, but one point is not practical.

Example 2 A photographic printing paper support was prepared in the same manner as in Example 1. However, the following composition 2 was prepared and used instead of the composition 1 so that the coating amount after curing was 25 g / m ² . Table 1 shows the evaluation results obtained in the same manner as in Example 1.

Composition 2 component Blending amount 2- (2-hydroxy-1,1-dimethylethyl) -5-hydroxymethyl-5-ethyl-1,3-dioxydiacrylate 35 parts by weight (trademark: KAYARAD R604 Nippon Kayaku Co., Ltd. (Formula (3)) Polyester acrylate 25 parts by weight (Trademark: Aronix M7100 Toa Gosei Chemical Industry Co., Ltd.) Titanium dioxide 40 parts by weight (Trademark A-220 Ishihara Sangyo Co., Ltd.)

Example 3 A support for photographic printing paper was prepared in the same manner as in Example 1. However, the following composition 3 was prepared and used instead of the composition 1, and the composition was applied such that the coating amount after curing was 25 g / m ² . Table 1 shows the evaluation results obtained in the same manner as in Example 1.

Composition 3 ingredients Blending amount Tricyclodecanylene diacrylate 15 parts by weight (Trademark: KAYARAD R684 Nippon Kayaku Co., Ltd., formula (8)) Cresol EO modified acrylate 15 parts by weight (Trademark: New Frontier CEA Daiichi Kogyo Pharmaceutical Co., Ltd.) Polyester acrylate 30 parts by weight (Trademark: Aronix M7100, Toagosei Kagaku Kogyo Co., Ltd.) Titanium dioxide 40 parts by weight (Trademark: Taipek A-220 Ishihara Sangyo Co., Ltd.)

Example 4 In order to obtain a surface resin coating layer having a laminated structure, the following composition 4, which is an electron beam curable resin composition, was separately mixed and dispersed in a paint conditioner for 1 hour to prepare a surface resin coating layer. Composition 4 components Blending amount 6EO Trimethylolpropane triacrylate 70 parts by weight (Trademark: Aronix M-360, Toagosei Kagaku Kogyo Co., Ltd.) Titanium dioxide 30 parts by weight (Trademark A-220, Ishihara Sangyo Co., Ltd.)

First, the composition 4 was applied on the surface of a polyester film used as a molding surface by using a wire bar so that the coating amount after curing would be 8 g / m ² .
Acceleration voltage: 175KV, absorbed dose: 2M
This coating layer was cured by irradiating it with an electron beam under the condition of rad.

Separately from this, the composition 3 was applied onto the surfaces of the paper base 1 and the paper base 2 using a wire bar so that the coating amount after curing was 25 g / m ² , and this coating liquid was used. The layer is superposed on the above-mentioned cured coating layer on the surface of the polyester film, and the electron beam is irradiated from the back of this polyester film under the conditions of accelerating voltage: 175 KV and absorbed dose: 2 Mrad to cure the electron beam curable resin coating layer. Then, the laminated polyester film obtained by adhering was peeled off to prepare a support for photographic printing paper. Table 1 shows the evaluation results obtained in the same manner as in Example 1.

Comparative Example 1 A photographic printing paper support was prepared in the same manner as in Example 1. However, the following composition 5 was prepared and used instead of the composition 1 so that the coating amount after curing was 25 g / m ² . Table 1 shows the evaluation results obtained in the same manner as in Example 1.

Composition 5 ingredients Blending amount Acrylic monophorine 20 parts by weight (Trademark: ACMO Kojin Co., Ltd.) Polyester acrylate 30 parts by weight (Trademark: Aronix M7100 Toa Gosei Chemical Industry Co., Ltd.) Titanium dioxide 50 parts by weight (Trademark: Taipaque A-220 made by Ishihara Sangyo Co., Ltd.)

Comparative Example 2 A photographic printing paper support was prepared in the same manner as in Example 1. However, the following composition 6 was prepared and used instead of the composition 1 so that the coating amount after curing was 25 g / m ² . Table 1 shows the evaluation results obtained in the same manner as in Example 1.

Composition 6 ingredients Blending amount Tricyclodecanylene diacrylate 10 parts by weight (trademark: KAYARAD R684 manufactured by Nippon Kayaku Co., Ltd., formula (8)) 30 parts by weight of cresol EO modified acrylate (trademark: New Frontier CEA Daiichi Kogyo Pharmaceutical Co., Ltd.) Polyester acrylate 30 parts by weight (Trademark: Aronix M7100 manufactured by Toagosei Kagaku Kogyo Co., Ltd.) Titanium dioxide 30 parts by weight (Trademark: Taipek A-220 Ishihara Sangyo Co., Ltd.)

Comparative Example 3 A photographic printing paper support was prepared in the same manner as in Example 1. However, the following composition 7 was prepared and used instead of the composition 1, and the composition was applied such that the coating amount after curing was 25 g / m ² . Table 1 shows the evaluation results obtained in the same manner as in Example 1.

Composition 7 components Blending amount Tricyclodecanylene diacrylate 55 parts by weight (Trademark: KAYARAD R684 Nippon Kayaku Co., Ltd., formula (8)) Polyester acrylate 15 parts by weight (Trademark: Aronix M7100 Toagosei Chemical Industry Co., Ltd. Made) Titanium dioxide 30 parts by weight (Trademark: Taipek A-220 manufactured by Ishihara Sangyo Co., Ltd.)

Comparative Example 4 A photographic printing paper support was prepared in the same manner as in Example 1. However, composition 1 was used and the coating amount after curing was 8
It was applied so as to be g / m ² . The evaluation results obtained in the same manner as in Example 1 are shown in the table.

[0066]

[Table 1]

Water vapor permeability, flexibility in Examples and Comparative Examples,
The measurement results of surface gloss are shown in the table. From Table 1, it can be seen that the water vapor permeability and the flexibility are changed depending on the compounding amount of the electron beam curable resin composition of the formula (1). The surface gloss is 50g / m ^{2 for} 24 hours (25 ° C, 90% R).
If it is H) or less, the rate of change in image clarity, which represents a change in surface gloss, is maintained at 0.85 or more, and a support for photographic printing paper is obtained that has little change in surface condition due to humidity changes in the atmosphere, and is flexible. There is no problem with sex.

[0068]

The photographic printing paper support of the present invention is an electron beam curable resin against a decrease in surface gloss due to environmental changes, especially humidity changes, which is a general drawback when an electron beam curable resin coating layer is provided. Maintains the surface properties of the coating layer and excels in image sharpness,
In addition, it is flexible and therefore extremely useful in practice.

Claims (2)

[Claims] 1. A cured product of a paper substrate containing natural pulp as a main component, and a composition containing an unsaturated organic compound which is formed on one surface of the paper substrate and is curable by electron beam irradiation as a main component. And a back surface resin coating layer formed on the other surface of the paper substrate and containing a film-forming synthetic resin as a main component, wherein the surface resin coating layer is at least one kind. The following formula (1)
In the unsaturated organic compound represented by the formula (1) and curable by electron beam irradiation, the weight ratio of the unsaturated organic compound of the formula (1) to the unsaturated organic compound other than the formula (1) is 20/80 to 70/30.
And a coating amount of the surface resin coating layer is 10 to 40 g / m.
^{2. A} support for photographic printing paper, which is ² . Embedded image [However, in the formula (1), R is tricyclo [5.2.1.
0 ^2.6 ] decanylene group, a tricyclo [5.2.1.0 ^2.6 ] decanylene group having a substituent, a 1,3-dioxyki group, or a 1,3-dioxyki group having a substituent. ] 2. The surface resin coating layer has a laminated structure of at least two layers including an inner resin coating layer adjacent to the paper base and an outermost resin coating layer arranged on the outermost side,
The support for photographic printing paper according to claim 1, wherein at least one of the coating layers constituting the surface resin coating layer is made of the electron beam cured product.