JP2593167B2 - Method for producing a support for photographic printing paper - Google Patents

Description

The present invention relates to a method for producing a photographic paper support. More particularly, the present invention relates to a method for producing a water-resistant photographic printing paper support in which the surface of a base paper is coated with an electron beam-curable resin to improve photographic properties.

[B] Prior Art In recent years, as a support for photographic printing paper, a paper in which the surface of a base paper as a support is coated with a polyolefin resin kneaded with a white pigment is mainly used. The reason for providing the polyolefin resin on the base paper is mainly to prevent the processing chemicals from penetrating into the base paper at the time of development, and this resin coating layer enables the development time to be shortened. Since no treatment chemicals remain inside, yellowing due to aging can be avoided. The coating of base paper with such a polyolefin resin is generally performed using a melt extruder.
Furthermore, an inorganic white pigment such as titanium dioxide is provided on the polyolefin resin layer on the surface of the photographic paper to improve the hiding power and whiteness of the photographic paper support and to improve the resolution of the photographic paper. Has been incorporated. However, the polyolefin resin has a very high viscosity even at the time of heat melting, and not only is it not easy to disperse an inorganic pigment such as titanium dioxide, but also the filling rate of the inorganic pigment is limited, and a certain degree of hiding power, white In order to obtain a certain degree, the resin coating thickness had to be increased. In addition, since such melt extrusion coating of a polyolefin resin is performed at a temperature not lower than the thermal decomposition temperature of the polyolefin resin, yellowing and pinholes due to the thermal decomposition of the resin occur in the resin coating layer. Furthermore, when the extrusion speed is increased, the polyolefin resin in a molten state is peeled off before being sufficiently cooled and solidified by the cooling roll, so that the releasability between the cooling roll and the resin coating surface is deteriorated, so-called “blocking”.
As a result, gloss unevenness called "horizontal unevenness" occurs, which causes a problem of deteriorating the quality of photographic paper as a final product. In addition, a method of adding a lubricant to a polyolefin resin in advance to prevent the occurrence of unevenness due to such “blocking” is generally known. However, when this method is employed, the molten polyolefin resin is melted and extruded when the polyolefin resin is extruded. The amount of smoke generated by the thermal decomposition of the lubricant from the surface of the surface increases, causing the cooling roll surface to become dirty, resulting in the deterioration of the quality of the resin-coated surface and the occurrence of the so-called "pear ground". Quality degradation, and was not a fundamental solution.

[C] Problems to be Solved by the Invention In manufacturing a resin-coated photographic paper support,
If the melt extrusion method is used, it is difficult to reduce the thickness of the resin coating layer while maintaining an appropriate hiding power, or to increase the coating speed without deteriorating the quality. There has been proposed a method for producing a water-resistant photographic printing paper support by applying an electron beam-curable resin composition into which a pigment has been kneaded, and irradiating the composition with an electron beam to form a coating layer (for example, Japanese Patent Application Laid-Open No. H11-157556). Japanese Patent Publication No. 60-17104). In this method, a coating liquid in which a high concentration of a white pigment is dispersed in a resin, such as an acrylate ester having an unsaturated bond, which can be polymerized by electron beam irradiation, is applied on a base paper for photographic printing paper, and polymerized by electron beam irradiation at room temperature. And a method of forming a resin coating layer on the base paper surface by performing crosslinking, so that the resin coating layer can be thinned without lowering the hiding power, and yellowing of the resin derived from the melt extrusion method, generation of pinholes, It is possible to produce a water-resistant photographic printing paper support without causing deterioration in the quality of the final product due to generation of blocking or satin finish. However, when a photographic paper support prepared by coating with an electron beam-curable resin as known to date is used as a photographic paper, the electron beam irradiation dose is not sufficient, that is, If the curing of the conductive resin is not sufficient, the processing chemicals are adsorbed to the resin coating layer in the developing step, and there is a problem that yellowing progresses with time. Radical active species remain in the electron beam-curable composition, causing fog in a photosensitive emulsion layer provided thereon, which has been a fatal problem as a support for photographic printing paper. Generally, electron beam-curable resins contain hydroquinone monomethyl ether and phenothiazine-based compounds as polymerization inhibitors, but compounds that already exist before electron beam irradiation lose their polymerization prevention function by electron irradiation and are thus formed. Decomposition products have problems such as causing new fog or coloring over time, and have not been a fundamental solution to the above problems.

[D] Means for Solving the Problems The present inventor has earnestly studied means for solving the above contradictory problems, and as a result, has reached the following invention. That is, in a water-resistant photographic printing paper support provided with an electron beam-cured composition coating layer comprising a white pigment and an electron beam-curable resin on at least one surface of the support, the electron beam-cured coating layer Was achieved with a water-resistant photographic paper support characterized in that it had been treated with a radical polymerization inhibitor. Then, the production method includes applying an electron beam-curable composition comprising a white pigment and an electron beam-curable resin to at least one surface of a base paper serving as a support, forming a coating layer by electron beam irradiation, and then forming a radical. A process for producing a water-resistant photographic printing paper support, characterized by treating with a polymerization inhibitor. That is,
The electron beam-curable composition is irradiated with a sufficient amount of electron beam in order to suppress the yellowing with time due to the adsorption of the processing chemicals to the resin coating layer in the development process. Residual radical active species in the resin coating layer that causes the elimination are reduced by deactivation by separately performing treatment with a radical polymerization inhibitor after electron beam irradiation, resulting in good development suitability and good emulsion suitability. A photographic printing paper support is obtained. Such a photographic printing paper support having good development suitability and good emulsion suitability,
It can be produced by curing an electron beam-curable composition containing a white pigment by irradiation with an electron beam and then performing a treatment with a radical polymerization inhibitor.

 Hereinafter, the present invention will be described in detail.

On the back surface of the photographic printing paper support of the present invention, a coating is formed by applying a polyolefin resin by a melt extrusion method as conventionally performed, or by applying an electron beam-curable resin and then irradiating with an electron beam. The resin coating layer can be formed by the method.

The photographic printing paper support of the present invention is one in which an electron beam polymerizable resin and a white pigment are mixed to form a resin coating layer.
As the electron beam polymerizable resin referred to herein, an unsaturated polyester having an electron beam reactive group at a molecular terminal or a molecular side chain, a modified unsaturated polyester, an acrylic polymer, a monomer having an unsaturated bond, and the like are used alone. Or with other solvents, and can be selected in consideration of the affinity between the base paper for photographic printing paper and the electron beam polymerizable composition and the affinity for processing materials such as photosensitive materials and developing solutions. Hereinafter, typical examples of the electron beam polymerizable resin will be described.

(A) polyester acrylate, polyester methacrylate, for example, Aronix M-5300, Aronix M-54
00, Aronix M-5500, Aronix M-5600, Aronix M-5700, Aronix M-6100, Aronix M-6200, Aronix M-6300, Aronix M
-6500, Aronix M-7100, Aronix M-803
0, Aronix M-8060, Aronix M-8100 (Trade name of Toagosei Chemical Industry Co., Ltd.), Viscort 70
0, Viscoat 3700 (trade name of Osaka Organic Chemical Industry Co., Ltd.), Kayarad HX-220, and Kayarad HX-620 (trade name of Nippon Kayaku Co., Ltd.).

(B) urethane acrylate, urethane methacrylate, for example, Aronix M-1100, Aronix M-12
00, Aronix M-1210, Aronix M-1250, Aronix M-1260, Aronix M-1300, Aronix M-1310 (all trade names of Towa Gosei Chemical Industry Co., Ltd.), Biscoat 812, Biscoat 823, Biscoat 823
(Above, trade names of Osaka Organic Chemical Industry Co., Ltd.), NK ester, U-108-A, NK ester, U-4HF (all, trade name of Shin-Nakamura Chemical Co., Ltd.) and the like.

(C) monofunctional acrylate, monofunctional methacrylate, for example, methyl acrylate, ethyl acrylate,
Butyl acrylate, 2-ethylhexyl acrylate, 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl acrylate, tetrahydrofurfuryl acrylate, phenoxyethyl acrylate, cyclohexyl acrylate, cyclohexyl methacrylate, benzyl acrylate, glycidyl methacrylate, N, N -Dimethylaminoethyl acrylate, N, N-dimethylaminoethyl methacrylate, N, N-diethylaminoethyl methacrylate, butoxyethyl acrylate and the like. Ethylene oxide-modified phenoxylated phosphoric acid acrylate Ethylene oxide-modified butoxylated phosphoric acid acrylate, as well as Alonix M-101, Aronix M-102, and Aronix M-11 as trade names of Toagosei Chemical Industry Co., Ltd.
1, Aronix M-113, Aronix M-114, Aronix M-117, Aronix M-152, Aronix M-154 and the like.

(D) polyfunctional acrylate, polyfunctional methacrylate, for example, 1,6-hexanediol diacrylate, 1,6
-Hexanediol dimethacrylate, neopentyl glycol diacrylate, diethylene glycol diacrylate, polyethylene glycol diacrylate, polyethylene glycol dimethacrylate, polypropylene glycol diacrylate, polypropylene glycol dimethacrylate, pentaerythritol diacrylate, trimethylolpropane hexaacrylate, isocyanuric acid diacrylate Acrylate, pentaerythritol triacrylate, isocyanuric acid triacrylate, trimerolpropane triacrylate, trimethylolpropane trimethacrylate, ethylene oxide-modified pentaerythritol tetraacrylate, propylene oxide-modified pentaerythritol tetraacrylate,
Propylene oxide-modified trimethylolpropane polyacrylate, ethylene oxide-modified trimethylolpropane polyacrylate, and the like. Alonix M-210, Aronix M-215, Aronix M-220, Aronix M-230, Aronix M-233, Aronix M-24 are trade names of Toa Gosei Chemical Industry Co., Ltd.
0, Aronix M-245, Aronix M-305, Aronix M-309, Aronix M-310, Aronix M-315, Aronix M-320, Aronix M-32
5, Aronix M-330, Aronix M-400, Aronix M-450, TO-458, TO-747, TO-755, THIC.T
A2 and the like.

In the electron beam curable composition used in the present invention, a rutile-type or atanase-type titanium dioxide, zinc oxide, talc, calcium carbonate, barium carbonate, barium sulfate, calcium sulfate, untreated white pigment such as silica,
Alternatively, it can be contained after surface treatment with siloxane, alumina, alcohol, or the like. The proportion of the white pigment in the electron beam-curable composition is preferably from 20% by weight to 80% by weight, and particularly preferably from 20% by weight to 70% by weight. This is because the white pigment does not have the concealing power expected to be extremely small, and if it is extremely large, not only does the ability of the electron beam-curable resin as a binder be insufficient, but also the amount of electron beam irradiation increases. This is because it causes an increase and adversely affects the base paper for photographic printing paper or internal chemicals.

In the electron beam curable composition of the present invention, as used in the conventional melt extrusion method of polyolefin resin, ultramarine blue, pigments and dyes such as cobalt violet, antioxidants, fluorescent brighteners, antistatic agents and the like Can be added in appropriate combination.

Base paper used as a support in the present invention is ordinary natural pulp paper, synthetic fiber, or so-called synthetic paper in which synthetic resin film is made into pseudo paper, or resin-coated paper provided with a water-resistant resin coating layer on the surface of the base paper, or Although a synthetic resin sheet can be used, a natural pulp paper mainly containing a wood pulp of a softwood pulp, a hardwood pulp, or a softwood mixed pulp is preferably used. Good paper preferably particularly restricted although not smooth, the thickness of the base paper, the basis weight 50g / m ² ~250g / m ² is preferred.

The base paper mainly composed of natural pulp, which is advantageously used in the method of the present invention, can contain various polymer compounds and additives. For example, dry paper strength agents such as starch derivatives, polyacrylamide, polyvinyl alcohol derivatives, and gelatin, sizing agents such as fatty acid salts, rosin derivatives, dialkyl ketene dimer emulsions, and wet papers such as melamine resins, urea resins, and epoxidized polyamides. Force enhancer, stabilizer, pigment, dye, antioxidant, optical brightener,
Various latexes, inorganic electrolytes, pH adjusters and the like can be appropriately combined and contained.

Further, in the present invention, a surface treatment such as a corona treatment of the base paper surface to improve the adhesiveness and wettability of the base paper and the electron beam curable composition, or a resin and a photosensitive emulsion formed by irradiation with an electron beam. A surface treatment such as corona treatment may be performed on the surface of the resin coating cured by irradiation with an electron beam in order to improve adhesion and wettability.

As a method of adjusting the electron beam-curable composition by mixing the white pigment with the electron beam-curable resin, a general pigment kneader can be used. For example, two-roll, three-roll, ball mill, kneader, high-speed mixer, homogenizer and the like.

As a method of applying the electron beam curable composition on the base paper, for example, blade coating, air doctor coating,
Methods such as air knife coat, spray coat, squeeze coat, air knife coat, reverse roll coat, gravure roll and transfer roll coat, and E-bar coat are used.

The thickness of the electron beam polymerizable composition layer applied on the base paper varies depending on the type of the base paper, but is 5 to 100 μm, more preferably 5 to 100 μm.
If the thickness is smaller than 50 μm, the thickness is liable to be affected by irregularities of the base paper, and pinholes are easily generated. If the thickness is larger than this, not only is it difficult to apply uniformly but also it is difficult to cure uniformly, which is not preferable in quality.

When the surface of the resin-coated paper is to be further mirror-finished, the surface to be treated is brought into contact with a mirror-finished roll, irradiated with an electron beam from the back surface, and cured, whereby the mirror-finish can be performed. Compared to the method of completely curing with one irradiation, the cost is remarkably inferior.However, after preliminary electron beam irradiation and partially curing the surface, it is brought into contact with a mirror roll, peeled off, and secondary irradiation is performed. There is also a method of curing.

When applying a mold, a desired mold surface such as a finely rough surface can be obtained by using a mold roll instead of the mirror roll.

Electron beam irradiation requires an accelerating voltage of 10
It is preferable to use an electron beam accelerator of 100 to 300 Kv, more preferably 100 to 300 Kv, so that the absorbed dose in one pass is 0.5 to 20 Mrad. If the accelerating voltage or the amount of electron beam irradiation is lower than this range, the penetrating power of the electron beam is too low to perform sufficient curing, and if it is higher than this range, not only does the energy efficiency deteriorate, but also the strength of the base paper decreases. Unfavorable effects on quality such as decomposition of resin and resin. The electron beam accelerator may be, for example, any of an electro curtain system, a scanning type, a double scanning type, and the like.

In addition, when irradiating with an electron beam, if the oxygen concentration is high, the curing of the electron beam polymerizable composition is hindered, so nitrogen, helium, substitution with an inert gas such as carbon dioxide is performed, and the oxygen concentration is 600 ppm or less, preferably 400 ppm. The irradiation is preferably performed in an atmosphere controlled as follows.

As described above, the photographic printing paper support obtained by curing the electron beam-curable composition by electron beam irradiation to form a film can be further treated with a radical polymerization inhibitor to greatly enhance the photographic properties of the electron beam-cured film layer. Can be improved. This is probably because unreacted radical species confined in the resin cured by electron beam irradiation are inactivated by the radical polymerization inhibitor. Examples of such radical polymerization inhibitors include dichlorobenzoquinones, trinitrobenzenes, nitrosobenzenes, butylcatechols, picric acids, nitrobenzoic acids, oxygen and active oxygen, cupric chloride, ferric chloride, and halogenated halides. Commonly known radical polymerization inhibitors such as cobalt, diphenylpicrylhydrazyl, tetraethylphenylenediamine, chloranil and iodine can be used. These radical polymerization inhibitors can be used alone or as a solution, and can be washed with water or a solvent after the treatment.

The support for photographic printing paper prepared according to the present invention can be used as a photographic printing paper by coating a photosensitive emulsion thereon.

[E] Action In the photographic printing paper support according to the present invention, the unreacted radical species in the coating layer cured by electron beam irradiation can be inactivated by the action of the radical polymerization inhibitor. Radical species do not remain even when the electron beam is irradiated in an amount necessary to sufficiently suppress the residual adsorption of the photosensitive emulsion layer, so that fogging of the photosensitive emulsion layer can be prevented.

[F] Examples Hereinafter, the present invention will be described in detail with reference to Examples, but the present invention is not limited to the Examples.

Example 1 Equivalent weight of polyethylene resin [low density polyethylene (density 0.918 g / cm ³ , MI5) and high density polyethylene (density 0.965 g / cm ³ , M17) on the back of photographic base paper having a basis weight of 120 g / m ² Mixture], using a base paper for photographic printing paper which was melt-extruded and coated with a thickness of 20 μm with a surface, subjected to a corona treatment, and then coated with an electron beam-curable composition having the following composition to a thickness of 20 μm. It was guided into an electron beam irradiation apparatus (Electron curtain, manufactured by ESI) which had been substituted (oxygen concentration: 200 ppm), and irradiated with an electron beam under the conditions of an acceleration voltage of 175 kv and an absorbed dose of 4 Mrad to prepare a support for photographic printing paper.

(Electron beam curable composition)

Rutile-type titanium dioxide 50% by weight Electron beam-curable resin 50% by weight The electron beam-curable resin uses an equal mixture of pentaerythritol triacrylate ester and tripropylene glycol diacrylate. This was performed using The prepared photographic paper support was immersed in a 3% 2,6-dichlorobenzoquinone alcohol solution at 45 ° C., washed with alcohol and distilled water, dried, and treated with a radical polymerization inhibitor. A support was prepared.

Example 2 Radical polymerization was inhibited in the same manner as in Example 1 except that the radical polymerization inhibitor was replaced with a solution composed of 0.05 M dilute sulfuric acid, 0.04 M cuprous chloride and 0.02 M hydrogen peroxide, and washing was performed using distilled water. A support for photographic printing paper which had been treated with the agent was obtained.

Comparative Example 1 The photographic printing paper support obtained in Example 1 was prepared without being treated with a radical polymerization inhibitor.

Comparative Example 2 A photographic printing paper support treated with a radical polymerization inhibitor was prepared in the same manner as in Example 1 except that the amount of electron beam irradiation was changed to 0.5 Mrad.

Comparative Example-3 A photographic printing paper support was prepared in the same manner as in Comparative Example-1, except that the amount of electron beam irradiation was changed to 0.5 Mrad.

Comparative Example 4 A photographic paper support laminated on both sides with a commercially available polyolefin resin was prepared.

(Emulsion fog test) A photosensitive emulsion layer was provided on the photographic paper support obtained in Examples 1 and 2 and Comparative Examples 1, 2, 3, and 4, and cured by a conventional method to form a film. After leaving at 50 ° C. for one month, a series of development processing was performed. Whiteness of photographic paper support provided with emulsion layer after development (Macbeth reflection densitometer,
RD-514, using a yellow filter) was used as a measure of emulsion fog.

(Residual developer test) A gelatin layer was provided on the photographic paper support obtained in Examples 1 and 2 and Comparative Examples 1, 2, 3, and 4 and a usual curing was performed. Was performed. The rate of change in the whiteness of the photographic paper support provided with a gelatin layer before and after development was used as a measure of the residual developer.

Table 1 summarizes the whiteness of the photographic printing paper support in the emulsion fog test and the whiteness change rate in the developer residual test. Naturally, the lower the whiteness, the higher the quality of the final product, photographic printing paper. The smaller the rate of change in whiteness, the smaller the residual processing chemicals during the development process, and the better the support for photographic printing paper.

[G] Effect of the Invention The present invention does not use a melt-extrusion method at the time of preparing a resin coating layer, so that not only does not cause gloss failure such as satin finish and horizontal unevenness, but also electron beam irradiation is sufficient to suppress residual developer. However, since the unreacted radical species in the electron beam-cured coating have been inactivated by the subsequent radical polymerization inhibitor treatment, even if a dry emulsion layer is provided thereon, fog does not occur. It is intended to provide a photographic printing paper support having excellent photographic properties. Further, the support for photographic printing paper prepared in the present invention provides a photographic printing paper which has little residual chemical after development processing and is excellent in color reproducibility and fading.

Claims (1)

(57) [Claims] An electron beam curable composition comprising a white pigment and an electron beam curable resin is applied to at least one surface of a support,
A method for producing a support for water-resistant photographic printing paper, comprising forming a coating layer by electron beam irradiation and treating with a radical polymerization inhibitor.