JPH07230141A - Supporting body for photographic paper - Google Patents

Abstract

PURPOSE:To provide a supporting body for photographic paper excellent secular change stability and coating adaptability of an under coating layer solution and having excellent sharpness, sensitivity and film sticking property of an emulsion. CONSTITUTION:The supporting body for photographic paper is formed by coating both surface of a base paper with a polyolefin resin and providing a under coating layer of a hydrophilic colloided binder composed of titanium dioxide treated with at least one of alumina or silica as a white pigment, a latex polymer and gelatin or its derivative on the side to be provided with a silver halide emulsion. A specific butadiene based latex is preferably used and the titanium dioxide treated with 0.5-4.0wt.% Al2O3 or SiO2 per the titanium dioxide is used as the white pigment.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a support for photographic printing paper, and more specifically, it has excellent temporal stability of a coating liquid for undercoat layer and its suitability for coating, and has sharpness, sensitivity and emulsion of photographic paper. The present invention relates to a support for photographic printing paper, which is excellent in film forming property.

[0002]

2. Description of the Related Art Conventionally, as a support for photographic printing paper,
It is well known that both sides of a base paper are coated with a resin composition mainly composed of a white pigment and a polyolefin resin. Since the support hardly absorbs the developing solution, the washing and drying after the processing can be greatly shortened, and the support has excellent dimensional stability.

However, as compared with the conventional baryta paper, the photographic printing paper using the polyolefin resin-coated support has a drawback that the sharpness of the image is inferior. It is expected that the reason is that the content of the white pigment in the polyolefin resin composition is limited due to the problem of operability, and thus the light shielding effect is poor.

Further, when a support coated with a polyolefin resin is used, there is a drawback that the contrast of a photographic image is lowered, which is expected to be due to insufficient light shielding effect and light transmission. It

As an improvement on the above-mentioned drawbacks, JP-A-59-
As described in JP-A-177542, it has been proposed to provide an undercoat layer containing 40% by volume or more of a white pigment and a hydrophilic colloid resin between a polyolefin resin coating layer and a silver halide emulsion layer.

However, in particular, titanium dioxide having a high refractive index is widely used as a white pigment, but it has strong photochemical activity and is poor in weather resistance and light resistance. Further, titanium dioxide was difficult to disperse when mixed with a hydrophilic colloid resin, particularly gelatin, and therefore the stability of the undercoat layer coating solution over time was poor, and the suitability for coating on a support was also poor. .

[0007]

DISCLOSURE OF THE INVENTION The present invention provides a support for photographic printing paper which is excellent in stability of undercoat layer coating liquid over time, coating suitability, sharpness of printing paper, sensitivity, and film-forming property of emulsion. With the goal.

[0008]

As a result of intensive studies to solve these problems, the present inventors have invented the support for photographic printing paper of the present invention.

That is, in the photographic paper support of the present invention, both sides of a base paper are coated with a polyolefin resin, and at least a white pigment, a latex polymer and a hydrophilic colloid bond are provided on the side on which a silver halide emulsion is provided. In a photographic paper support provided with an undercoat layer containing an agent, the white pigment is titanium dioxide surface-treated with at least one of alumina and silica, and the hydrophilic colloid binder is gelatin or a derivative thereof. It is characterized by being.

In the support for photographic printing paper according to the present invention, the surface-treated titanium dioxide is the same as titanium dioxide.
It is characterized by being surface-treated in the range of 0.5 to 4.0% by weight as Al ₂ O ₃ or SiO ₂ .

In the photographic printing paper support of the present invention, the latex polymer is a styrene-butadiene copolymer, a methyl methacrylate-butadiene copolymer, a methyl methacrylate-styrene-butadiene copolymer or a derivative thereof. It is characterized by being at least one kind.

In the photographic paper support of the present invention, the surface-treated titanium dioxide is 40 to 70% by weight of the undercoat layer, and the latex polymer and the hydrophilic colloid binder are 60 to 30% by weight of the undercoat layer. Characterize.

Further, the weight ratio of the latex polymer to the hydrophilic colloid binder is 9: 1 to 3: 7.

The support for photographic printing paper of the present invention will be described in detail below. The photographic paper support of the present invention comprises
An undercoat layer is provided on the side where a silver halide emulsion coated with a polyolefin resin is provided, and surface-treated titanium dioxide is contained in the undercoat layer.

The surface-treated titanium dioxide can be uniformly dispersed when mixed with the hydrophilic colloid binder in the undercoat layer coating solution, and the stability of the undercoat layer coating solution over time is excellent. Furthermore, when it is coated on a polyolefin resin coating layer using the prepared undercoat layer coating liquid, the coating suitability is also extremely excellent, and it exerts an effect on the film-forming property of the emulsion as photographic paper, and has excellent sharpness and sensitivity. Obtainable.

The surface-treated titanium dioxide of the present invention is
As a dry solid content of the undercoat layer in the undercoat layer coating liquid, 30 to
The purpose is achieved by containing 80% by weight,
From the viewpoint of the effect of the present invention and the film strength, in the present invention, 4
It is preferable to contain 0 to 70% by weight. It is more preferably 45 to 65% by weight. Here, if it is less than 30% by weight, the sharpness of the printing paper is inferior, and if it is more than 80% by weight, the stability of the coating solution with time and the film forming property of the emulsion are inferior, which is not preferable.

Regarding such surface-treated titanium dioxide, rutile type or anatase type is used as titanium dioxide, and it is preferable that the average particle size in a directional measurement by an electron microscope is 0.08 to 0.5 μm. The surface treatment with alumina or silica is performed by coating the surface of titanium dioxide by a method such as adding a water-soluble aluminum compound or a water-soluble compound of silicon to an aqueous slurry of titanium dioxide, followed by neutralization and precipitation. Can be done.

The surface-treated titanium dioxide is preferably surface-treated in the range of 0.5 to 4.0% by weight as SiO ₂ and Al ₂ O _{3 based on} the weight of titanium dioxide. Here, if the amount of the surface-treated layer exceeds 4.0% by weight, the properties of the pigment other than the light resistance are affected and the properties of titanium dioxide deteriorate, whereas if it is less than 0.5% by weight, the light resistance is reduced. It is difficult to obtain the effect. Furthermore,
When the coating amount of titanium dioxide to be surface-treated is out of the range of the present invention, the dispersibility with the latex polymer and the hydrophilic colloid binder is lowered, and the stability of the undercoat layer coating solution over time is poor, and the polyolefin resin coating layer The coating aptitude tends to be inferior.

In the photographic printing paper support of the present invention, the coating amount of the undercoat layer coated on the polyolefin resin coating layer is preferably 0.5 g / m ² or more, more preferably 2 g / m ^2. That is all.

Between the subbing layer and the silver halide emulsion layer,
An intermediate layer can be provided for the purpose of preventing irradiation and fogging, but the thickness of the coating layer of the intermediate layer is 4 to 5 μm.
m or less is preferable, and when the thickness of the coating layer of the intermediate layer is thicker than 4 to 5 μm, the sharpness becomes poor.

The latex polymer used in the undercoat layer of the present invention includes styrene-butadiene copolymer, methyl methacrylate-butadiene copolymer, methyl methacrylate-styrene-butadiene copolymer, acrylonitrile-butadiene copolymer. Polymers, styrene polymers, isoprene polymers, butadiene polymers, vinyl acetate-acrylic acid ester copolymers, acrylic acid ester polymers, vinyl acetate-ethylene copolymers, urethane polymers, vinyl chloride polymers, vinylidene chloride Examples thereof include polymers and their derivatives. Among these, when using at least one or more of a styrene-butadiene copolymer, a methyl methacrylate-butadiene copolymer, a methyl methacrylate-styrene-butadiene copolymer or a derivative thereof, a silver halide emulsion layer and It is preferable in terms of adhesiveness with the polyolefin resin coating layer.

The hydrophilic colloid binder used in the undercoat layer of the present invention is characterized in that it is gelatin or a derivative thereof, and specifically, lime-treated gelatin, acid-treated gelatin, enzyme-treated gelatin and the like. Examples thereof include gelatin or a gelatin derivative reacted with an anhydride of dibasic acid.

In the undercoat layer of the present invention, in addition to the above-described white pigment made of surface-treated titanium dioxide, inorganic pigments such as calcium carbonate, silica, kaolin, and the like, ultraviolet absorbers such as benzotriazole-based and benzophenone-based, and interfaces. Various materials such as activators, hardeners, dyes and antifoggants may be added to such an extent that the effects of the present invention are not impaired.

As the polyolefin resin of the present invention, at least one kind of low density polyethylene, medium density polyethylene, high density polyethylene, polypropylene, polybutylene, ethylene-propylene copolymer and the like can be used.

Further, the polyolefin resin composition may contain various additives. White pigments such as rutile-type or anatase-type titanium dioxide, zinc oxide, talc, etc., as release agents, fatty acid amides such as stearic acid amide and arachidic acid amide, fatty acid metal salts such as zinc stearate and magnesium stearate, polyorgano. An organosilicon compound such as siloxane, a hindered phenol compound as an antioxidant, cobalt blue, ultramarine, a fluorescent whitening agent, and the like can be appropriately contained as a color pigment.

As the base paper used in the present invention, ordinary natural pulp paper, synthetic fiber paper or a mixed paper thereof, synthetic paper of synthetic resin film and the like are used. In particular, base paper made of natural pulp paper having good surface smoothness is preferable.

In the base paper, a sizing agent, a wet paper strength enhancer, a filler, a pH adjusting agent, a coloring agent, a coloring dye, a fluorescent agent, etc., which are used in ordinary papermaking, a starch type, a polyvinyl alcohol type, or a surface size, Properly contains water-soluble polymers such as gelatin, inorganic or organic antistatic agents such as sodium chloride, potassium chloride, sodium polystyrene sulfonate, pigments such as kaolin, clay, calcium carbonate, coloring pigments, dyes, fluorescent agents, etc. can do.

The support for photographic printing paper in the present invention includes
Various back coat layers can be provided for the purpose of preventing electrification and curling. The material of the back coat layer is colloidal silica, colloidal synthetic hectorite,
Sodium chloride, polystyrene sulfonate, hydrophilic binder, latex polymer, pigment, surfactant and the like can be used.

The photographic printing paper support of the present invention is coated with various photographic constituent layers for various purposes such as color photographic printing paper, black-and-white photographic printing paper, typesetting printing paper, copy printing paper and the like. Can be used. For example, silver chloride, silver bromide, silver chlorobromide,
An emulsion layer of silver iodobromide or the like can be provided. It is also possible to provide a color coupler in the silver halide emulsion layer to provide a multilayer silver halide color photographic constituent layer. As the binder, in addition to usual gelatin, polyvinylpyrrolidone,
Polyvinyl alcohol or the like can be used. The photographic constituent layer may contain a sensitizing dye, a chemical sensitizer, an antifoggant, a hardener, a fluorescent whitening agent, an antistatic agent, a pH adjusting agent and the like.

The photographic printing paper of the present invention is subjected to various treatments such as exposure, development, stopping, fixing, bleaching and stabilizing as described in "Photosensitive Materials and Handling Methods" (Kyoritsu Shuppan, Goro Miyamoto). It is applied to form a photographic image.

As the coating machine for coating various photographic constituent layers such as the undercoat layer and the silver halide emulsion layer of the present invention, the back coat layer, etc., there are E bar, roll coater, rod coater, air knife coater, blade coater, Fountain coaters, die coaters and the like can use various coating machines. In particular, in the coating of the undercoat layer and the photographic constituent layer, E bar is used to continuously and simultaneously coat the emulsion, thereby improving the properties such as film attachment and surface quality of the emulsion.

[0032]

The present invention will be described in more detail with reference to the following examples, but the present invention is not limited thereto.
The parts and% in the examples mean parts by weight and% by weight, respectively.

Example 1 A backside of a base paper having a basis weight of 170 g / m ² was melt-extrusion coated with a 1: 1 mixture of low-density polyethylene and high-density polyethylene to a thickness of 30 μ to form a polyolefin resin coating layer. . On the surface of the base paper, a polyolefin resin composition prepared by mixing 10% titanium dioxide in a mixture of low density polyethylene: high density polyethylene 5: 4 was used.
The polyolefin resin coating layer was provided on the surface of the base paper by melt extrusion coating to a thickness of 0 μm.

On the polyolefin resin coating layer on the surface of the base paper, an undercoat layer coating solution having the following composition was applied by a test E bar so as to have a dry film thickness of 3 μm to obtain a support for photographic printing paper of the present invention. . Methyl methacrylate-butadiene latex (solid) 85 parts Gelatin 5% liquid (solid) 15 parts Surface-treated rutile titanium dioxide (Al ₂ O ₃ 2%, SiO ₂ 1%) 100 parts Add water to the above ingredients And stirred to prepare an undercoat layer coating liquid having a solid content concentration of 15%.

Further, an undercoat layer, an emulsion layer and a protective layer were simultaneously provided by an E bar to prepare a black and white photographic printing paper. The emulsion layer is
Hexachloroiridium (III) potassium salt 1.2 × 1
ArBr / AgCl / produced by dispersing and producing 19.2 g of silver halide grains as silver nitrate in the presence of 0 ^-5 g.
A silver halide photographic emulsion composition having AgI = 95 / 4.5 / 0.5 (mol%) was contained in 14.4 g of gelatin, and sulfur sensitization and gold sensitization were performed at optimum sensitivity with an average grain size of 0.6 μm. Sensitized by the method of (1), containing a neutral silver halide photographic emulsion substantially consisting of [0, 0, 1] surface, and further containing gelatin necessary for film formation, an appropriate amount of stabilizer and sensitization. Contains dyes, coating aids, hardeners, optical brighteners, thickeners, filter dyes, etc., silver nitrate 2.2 g / m ² , gelatin 4 g / m ² .
The undercoat layer and the protective layer were coated with the coating amount corresponding to m ² by the E-bar method at a coating speed of 200 m / min to perform multilayer coating and drying. The protective layer contains a coating aid and a hardening agent in addition to gelatin equivalent to ² g / m ² .

Example 2 Al ₂ O ₃ 2% and S used in the undercoat layer coating solution of Example 1
Instead of titanium dioxide surface-treated with 1% of iO ₂ , Al ₂
A support for photographic printing paper of the present invention was produced in the same manner as in Example 1 except that titanium dioxide surface-treated with O ₃ 4% and SiO ₂ 3% was used to obtain a black and white photographic printing paper.

Example 3 A photographic printing paper support of the present invention was prepared in the same manner as in Example 1 except that the composition of the undercoat layer coating solution of Example 1 was changed to the following composition of the undercoat layer coating solution. A photographic printing paper was obtained. Methyl methacrylate-butadiene latex (solid) 35 parts Gelatin 5% liquid (solid) 65 parts Surface-treated rutile titanium dioxide (Al ₂ O ₃ 2%, SiO ₂ 1%) 100 parts

Example 4 A photographic printing paper support of the present invention was prepared in the same manner as in Example 1 except that the composition of the undercoat layer coating solution of Example 1 was changed to the following composition of the undercoat layer coating solution. A photographic printing paper was obtained. Methyl methacrylate-butadiene latex (solid) 85 parts Gelatin 5% liquid (solid) 15 parts Surface-treated rutile titanium dioxide (Al ₂ O ₃ 2%, SiO ₂ 1%) 200 parts

Example 5 A photographic printing paper support of the present invention was prepared in the same manner as in Example 1 except that the composition of the undercoat layer coating solution of Example 1 was changed to the following composition of the undercoat layer coating solution. A photographic printing paper was obtained. Methyl methacrylate-butadiene latex (solid) 85 parts Gelatin 5% liquid (solid) 15 parts Surface treated rutile titanium dioxide (Al ₂ O ₃ 2%, SiO ₂ 1%) 50 parts

Example 6 Example 1 was repeated except that the latex polymer used in the formulation of the undercoat layer coating solution of Example 1 was replaced with methyl methacrylate-butadiene latex and methyl methacrylate-styrene-butadiene latex was used. A support for photographic printing paper of the present invention was produced in the same manner as in 1. to obtain a black-and-white photographic printing paper.

Example 7 The same procedure as in Example 1 was repeated except that the latex polymer used in the coating solution for the undercoat layer in Example 1 was replaced with styrene-butadiene latex instead of methyl methacrylate-butadiene latex. The support for photographic printing paper of the present invention was produced to obtain a black and white photographic printing paper.

Example 8 The photographic printing of the present invention was carried out in the same manner as in Example 1 except that the latex polymer used in the coating solution for the undercoat layer in Example 1 was replaced with an acrylonitrile-butadiene latex instead of the methyl methacrylate-butadiene latex. A black-and-white photographic printing paper using a paper support was obtained.

Example 9 Al ₂ O ₃ 2%, SiO _{2 in} the undercoat layer coating liquid formulation of Example 1
Instead of titanium dioxide surface-treated with 1%, Al ₂ O ₃ 4
% Example 1 except that titanium dioxide surface-treated with 10% was used.
A support for photographic printing paper of the present invention was produced in the same manner as in 1. to obtain a black-and-white photographic printing paper.

Comparative Example 1 A photographic printing paper support of the present invention was prepared in the same manner as in Example 1 except that the composition of the undercoat layer coating solution of Example 1 was changed to the composition of the undercoat layer coating solution described below. I got the photographic paper. Gelatin 5% liquid (solid) 100 parts Surface-treated rutile titanium dioxide (Al ₂ O ₃ 2%, SiO ₂ 1%) 50 parts

Comparative Example 2 A photographic paper support of the present invention was prepared in the same manner as in Example 1 except that the composition of the undercoat layer coating solution of Example 1 was changed to the composition of the undercoat layer coating solution described below. I got the photographic paper. Methyl methacrylate-butadiene latex (solid) 85 parts Gelatin 5% liquid (solid) 15 parts Rutile titanium dioxide (untreated surface) 100 parts

Comparative Example 3 A photographic paper support of the present invention was prepared in the same manner as in Example 1 except that the composition of the undercoat layer coating solution of Example 1 was changed to the following composition of the undercoat layer coating solution. I got the photographic paper. Methyl methacrylate-butadiene latex (solid) 85 parts Surface-treated rutile titanium dioxide (Al ₂ O ₃ 2%, SiO ₂ 1%) 100 parts

The black and white photographic printing papers obtained in Examples 1 to 8 and Comparative Examples 1 to 3 were evaluated by the following methods. The following Table 1 shows the evaluation results of sharpness (MTF), stability of the undercoat layer coating solution over time, coating suitability of the undercoat layer coating solution, and emulsion film formation. The MTF (modulation transfer function) in Table 1 shows a value at 5 cycles / mm.

[Sensitivity] The black-and-white photographic printing papers obtained in Examples and Comparative Examples were subjected to wedge exposure, printing, and black-and-white development treatment with a D-72 developer, and then density measurement was performed to compare the sensitivities. Regarding the relative sensitivity, the black and white photographic printing papers of Examples were equal to or higher than those of Comparative Examples.

[Sharpness] Regarding the sharpness, an unexposed sample was exposed using a sine wave chart, the density was measured with a microdensitometer, and the modulation transfer function (MTF) was obtained and compared. The closer the value is to 1, the better.

[Stability of Undercoat Layer Coating Liquid with Time] The stability of the undercoat layer coating liquid (solid content: 15%) with time was evaluated by the degree of precipitation after standing at 40 ° C. for one day. The evaluation criteria are ○: no precipitation. Δ: Some precipitation occurred. X: A large amount of precipitation was not possible for practical use.

[Applicability of coating liquid for undercoat layer] The coating suitability of the coating liquid for undercoat layer was evaluated by coating with a test E bar at 50 m / min. The evaluation criteria are ○: good surface quality. Δ: There is uneven coating. X: Unusable due to large coating unevenness.

[With Emulsion Film] With respect to the emulsion film, the photographic constituent layers of the color photographic papers obtained in Examples and Comparative Examples were scratched in a grid pattern so as to reach the polyolefin resin layer with a razor. After the cellophane tape was pressure-bonded thereon, the area ratio of the photographic constituent layers to the support when it was rapidly peeled off was shown. A value of 100% means that there is no peeling at all.

[0053]

[Table 1]

As is clear from Table 1, the photographic printing papers using the photographic printing paper supports of Examples 1 to 9 of the present invention were:
Various characteristics were excellent. On the other hand, the photographic printing papers using the support for photographic printing papers of Comparative Examples 1 to 3 were all inferior in sharpness. In particular, the photographic printing paper of Comparative Example 1 was good in the stability of the undercoat layer coating solution and the coatability, but the film-forming property of the emulsion was poor. The photographic printing papers of Comparative Examples 2 and 3 were inferior in the stability of the undercoat layer coating liquid over time and the coating property.

[0055]

INDUSTRIAL APPLICABILITY The support for photographic printing paper of the present invention is excellent in the stability of the undercoat layer coating solution over time and the suitability for coating, and is excellent in the sharpness and sensitivity of the printing paper and the film forming property of the emulsion.

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Claims (5)

[Claims] 1. A photographic print in which both sides of a base paper are coated with a polyolefin resin, and an undercoat layer containing at least a white pigment, a latex polymer, and a hydrophilic colloid binder is provided on the side on which a silver halide emulsion is provided. In a paper support, the white pigment is titanium dioxide surface-treated with at least one of alumina and silica, and the hydrophilic colloid binder is gelatin or a derivative thereof. body. 2. The surface-treated titanium dioxide is surface-treated in the range of 0.5 to 4.0 wt% as Al ₂ O ₃ or SiO ₂ with respect to titanium dioxide, respectively. The support for photographic printing paper according to claim 1. 3. The latex polymer is at least one of a styrene-butadiene copolymer, a methyl methacrylate-butadiene copolymer, a methyl methacrylate-styrene-butadiene copolymer or a derivative thereof. The support for photographic printing paper according to claim 1 or 2. 4. The surface-treated titanium dioxide is used as an undercoat layer.
% To 70% by weight, latex polymer and hydrophilic colloid binder in 60 to 30% by weight of the subbing layer. 5. The photographic paper support according to claim 1, wherein the weight ratio of the latex polymer and the hydrophilic colloid binder is 9: 1 to 3: 7. .