JP3356587B2 - Support for photographic materials - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a paper substrate (hereinafter sometimes referred to simply as "base paper") on the side on which one of the photographic image forming layers is to be provided, using paper mainly composed of natural pulp as a substrate. The present invention relates to a support for a resin-coated paper type photographic material, which is coated with a thermoplastic resin layer, and is preferably coated on the opposite side of the base paper surface with a resin capable of forming a film. ), And the storage stability with respect to the silver halide photosensitive layer is remarkably improved.
Moreover, an excellent resin-coated paper-type photographic material support capable of providing a photographic material which is remarkably improved in releasability from a cooling roll at the time of production of the support and does not generate uneven peeling, and therefore has good gloss. It is about.

[0002]

2. Description of the Related Art Conventionally, a support for a resin-coated paper type photographic material in which a base paper mainly composed of natural pulp is coated with a thermoplastic resin layer is well known. For example, Japanese Patent Publication No. 55-12584 discloses a technique for a support for photographic materials in which a base paper is coated with a resin having a film-form performance, preferably a polyolefin resin. U.S. Pat. No. 3,501,298 discloses a technique for a photographic material support in which both sides of a base paper are coated with a polyolefin resin.
Since the rapid photographic processing method for silver halide photographic light-sensitive materials was applied, supports for photographic materials in which both sides of a base paper were coated with a polyethylene resin have been mainly used for photographic printing paper. If necessary, a titanium dioxide pigment is usually contained in the resin layer on the side on which one of the photographic image forming layers is provided to impart sharpness.

Hitherto, anatase type and rutile type titanium dioxide pigments have been known as titanium dioxide pigments contained in a resin layer on the photographic image forming side of a support for a resin-coated paper type photographic material. Further, the surface of titanium dioxide particles is not coated with titanium dioxide pigment, or the surface of titanium dioxide particles as described or exemplified in JP-A-52-35625 and JP-A-57-108849 is hydrated. Titanium dioxide pigments coated with hydrated metal oxides such as aluminum and hydrous silicon oxide;
No. 5625, Japanese Patent Publication No. 58-43734, Japanese Patent Publication No. 61-26552, etc. Titanium dioxide pigments that have been coated with a substance are known.

On the other hand, if a particularly high sharpness (sometimes referred to as sharpness) of the printed image is required for photographic materials, some resin-coated paper type photographic material supports are also known. ing. For example, (1) a high concentration of titanium dioxide pigment contained in a resin layer,
(2) a titanium dioxide pigment in a resin layer containing a rutile type pigment; (3) zinc stearate, calcium stearate, zinc palmitate, etc., as described in JP-B-58-43734. A resin layer containing a titanium dioxide pigment by adding a surfactant represented by a metal soap. (4) As the titanium dioxide pigment in the resin layer, the particle surface is coated with the organic substance as described above. Known are those containing a treated, so-called, organically treated titanium dioxide pigment.

[0005] However, these resin-coated paper-type supports for paper-type photographic materials have an inadequate sharpness and have some other serious problems in photographic and production properties. In fact, satisfactory results have not yet been obtained.

First, when the concentration of the titanium dioxide pigment in the resin layer of the support for a resin-coated paper type photographic material is increased, a support for a photographic material having a high sharpness of a printed image can be obtained. Significant photographic and manufacturability problems often arise. That is, the side of the base paper on which the photographic image forming layer is provided (hereinafter, the side on which the photographic image forming layer is provided is the front side, the resin layer coated on the front side is the front resin layer, the opposite side is the back side, and the resin layer coated on the back side is Is sometimes referred to as a backing resin layer). A resin-coated paper for use as a support for photographic materials, in which the surface of which is coated with a thermoplastic resin layer containing a titanium dioxide pigment, particularly a polyethylene-based resin layer, is usually coated on a running base paper. Using a melt extruder, a thermoplastic resin composition containing a titanium dioxide pigment is cast into a film from the slit die and coated, pressed between a pressure roll and a cooling roll, and cooled. It is manufactured in a series of steps of peeling. However, when a thermoplastic resin composition containing a titanium dioxide pigment, particularly a polyethylene-based resin composition, is melt-extruded and coated on a base paper in a film form from a slit die, the releasability of the resin-coated paper from the cooling roll deteriorates. However, horizontal step-like unevenness in the width direction, which is referred to as peeling unevenness, occurs on the resin-coated paper surface.

As a result, the present inventor has conducted various studies on the factors. As a result, it was found that the occurrence of uneven peeling was caused by the type and properties of a thermoplastic resin composition containing a titanium dioxide pigment, in particular, a polyethylene resin composition, The type, properties, content, etc., of the titanium dioxide pigment to be contained in the resin composition largely depend on it, and even if the conventionally known titanium dioxide pigment as described above is contained in the thermoplastic resin composition, peeling occurs. It turned out that the unevenness could not be improved. Also,
As the thickness of the surface resin layer of the resin-coated paper increases, particularly when the thickness is 15 μm or more, or as the production speed of the resin-coated paper increases, specifically, 100 m / min or more, particularly 150 m / min or more In this case, it was found that the releasability of the resin-coated paper from the cooling roll deteriorated. Originally, having a mirror surface or a glossy surface or a slightly rough surface described in JP-B-62-19732,
Although the resin-coated paper for photographic materials for glossy use requires a high degree of smoothness, when this uneven peeling occurs, the photographic material using the resin-coated paper as a support also generates uneven gloss, resulting in poor glossiness. Only materials can be obtained, and there is a problem that photographic materials for glossy use are completely inappropriate and have no commercial value.

Second, when a rutile-type titanium dioxide pigment is used as a titanium dioxide pigment to be contained in a surface resin layer of a support for a resin-coated paper type photographic material, the ratio is higher than when an anatase type pigment is used. Thus, a photographic material support having a considerably high sharpness of a printed image can be obtained, but another serious problem in photographic aptitude arises. That is, the resin surface containing the titanium dioxide pigment on the photographic image forming side of the photographic material support has a yellow tint due to the rutile type titanium dioxide pigment,
There was a problem that a support for a photographic material having a clear whiteness could not be obtained.

Third, as a result of the study by the present inventor, when the titanium dioxide pigment is contained in the surface resin layer of the support for the resin-coated paper type photographic material, in particular, in the polyolefin resin layer,
Even if a surfactant represented by a metal soap such as zinc stearate, calcium stearate, and zinc palmitate is added, the sharpness of the printed image of the photographic material support is
It turned out that there was a problem that it was not substantially high.

In general, as a method for incorporating a titanium dioxide pigment into a surface resin layer of a support for a resin-coated paper type photographic material, a conventional melt kneading machine such as a Banbury mixer, a kneader, or a kneading extruder is used. Create a so-called master batch in which the pigment is contained in the resin in high concentration in advance,
Melt extrusion coating of a thermoplastic resin composition obtained by diluting and mixing it in a desired ratio with a diluting resin, or preparing a so-called compound in which a pigment is initially contained in a resin at a desired composition ratio, and forming by melt extrusion coating It is usual to work.
The main purpose of the metal soap originally added to the surface resin layer of the resin-coated paper type photographic material support is to produce the photographic material support by melt extrusion coating. The purpose is to improve the releasability between the cooling roll and the resin-coated surface.

However, as a result of the study by the present inventor, new findings have been found regarding the effect of the metal soap in the surface resin layer. That is, the concentration of the metal soap added in preparing the master batch or the compound of the titanium dioxide pigment in the surface resin layer of the support for the resin-coated paper type photographic material was 1.5% by weight based on the titanium dioxide pigment. Up to 0.15% by weight based on the resin composition, the sharpness of the printed image of the support for photographic materials is increased, but at this content, the releasability is poor, When the content is in the range of 1.5% to 7.5% by weight and 0.15% to 0.75% by weight based on the resin composition, the releasability is improved with the addition amount. It has been found that the sharpness of the printed image of the photographic material support is considerably reduced, sometimes lower than the case without the metal soap.

Further, when the content is more than that, the sharpness of the printed image of the photographic material support gradually decreases with the added amount, so that the generation of oily smoke increases, and the melt-extrusion coating at the time of melt extrusion coating is increased. It was found that the suitability for production was extremely poor. As described above, even when a metal soap is added when a titanium dioxide pigment is added to the surface resin layer of the resin-coated paper-type photographic material support, a photographic material support having high print image sharpness is obtained. There was a problem that can not be.

Fourth, as a result of investigations by the present inventors, as a titanium dioxide pigment to be contained in the surface resin layer, particularly in the polyolefin resin layer of the support for resin-coated paper type photographic materials,
It has been found that the use of an organically treated titanium dioxide pigment has a problem that the sharpness of a printed image of the photographic material support is not substantially high. That is, a metal soap typified by zinc stearate or the like together with an organically treated titanium dioxide pigment in the surface resin layer of the resin-coated paper-type photographic material support exhibits sufficient releasability during the production of the photographic material support. When added to the amount, the sharpness of the printed image of the photographic material support was found to be almost the same as that in the case of using a titanium dioxide pigment not subjected to organic treatment. .

Fifthly, halogenation using a resin-coated paper in which the front side of a base paper mainly composed of natural pulp is coated with a thermoplastic resin containing a titanium dioxide pigment, particularly a polyolefin resin composition, is used as a support. In the case of silver photographic materials, when stored after manufacture, if stored for a long period of time, especially when stored under high temperature and high humidity, unexposed portions of the photographic material called fog can be developed during development processing And the sensitivity of the photographic material is unduly increased or decreased. In addition, there is another problem that the tone of the photographic material changes and the tone becomes soft.

The inventors of the present invention have conducted various studies on the factors. As a result, the change in photographic characteristics of the silver halide photographic material using the resin-coated paper as a support, that is, the storage stability of the silver halide photographic material, was determined to be titanium dioxide. Thermoplastic resin compositions containing pigments, especially polyolefin resin compositions, especially the types and properties of polyethylene resin compositions, especially the types of titanium dioxide pigments to be contained in the thermoplastic resin composition,
It depends greatly on the properties, contents, etc., and it is not possible to improve the storability of the silver halide photographic material even if the conventionally known titanium dioxide pigment as described above is contained in the thermoplastic resin composition. found.

Heretofore, there have been several technical proposals for improving the releasability of a thermoplastic resin-coated paper, particularly a polyethylene resin-coated paper, for use as a support for photographic materials. As a typical method for improving the releasability during the production of a polyethylene-based resin-coated paper, it has been proposed to include various release agents in a polyethylene-based resin composition. For example, specific fatty acid amides described in JP-A-60-176036,
Various release agents such as polyalkylene glycol compounds described in JP-A-30841, fluorine-containing polymers described in JP-A-64-9444, and α-olefin-modified silicones described in JP-A-4-143748 have been proposed. I have. However,
Even if these release agents are contained in the polyethylene resin composition, the effect of improving the releasability is extremely insufficient,
At a production speed of 100 m / min or more, especially at a speed of 150 m / min or more, it has little or no effect. Instead, the adhesiveness between the base paper and the polyethylene resin layer is deteriorated, or the paper is coated on the polyethylene resin coated paper. In this case, the adhesion between the photosensitive layer or the photographic image forming layer and the polyethylene resin layer deteriorates.

Another attempt to improve the releasability during the production of polyethylene-based resin-coated paper is disclosed in JP-B-62-19732.
Use of micro-roughened cooling rolls described in Japanese Patent Publication
Use of a cooling roll embedded with a fluorine-based resin described in 1-24292 JP, furthermore, the melting peak described in JP-A-1-129249 is 110 ° C. or more, and the melt index is 5-20 g / Use of a low-density polyethylene resin for 10 minutes, and a low-density polyethylene resin described in JP-A-6-242549 having an extraction amount of hexane of 3% by weight or less and titanium dioxide having an oxidation induction period of 70 to 1000 seconds. Techniques for using pigment resin compositions in combination have been proposed.
However, even if these cooling rolls and resins are used, the effect of improving the releasability of the polyethylene-based resin-coated paper is insufficient, and the effect of improving the releasability at a production speed of 100 m / min or more, particularly 150 m / min or more. Was quite inadequate.

On the other hand, there are several proposals for improving the storage stability of a silver halide light-sensitive material having as a support paper, especially a resin-coated paper having a paper mainly composed of natural pulp as a substrate. JP-B-49-30446 and JP-B-50-33652 disclose the side on which a photosensitive layer is provided because decomposition products and oxides of resin generated during melt extrusion coating cause fogging of emulsions of photographic paper. A resin-coated paper-type photographic paper support is proposed in which the resin layer is composed of two layers, and the upper resin layer adjacent to the photosensitive layer is melt-extruded and coated at a low temperature. However, the silver halide light-sensitive material having the support not only has an insufficient storage stability, but also has a problem in that the fluidity of the resin layer becomes unstable due to the different temperatures of the two layers of the resin composition, and the molding process The properties were extremely insufficient. In addition, Tokiko Sho 54
Japanese Patent Application Laid-Open No. 9-9884 proposes an antifogging resin-coated paper-type photosensitive material support in which a base paper is coated with a polyolefin resin containing a hydroxy-substituted-triazolopyrimidine compound. However, the use of the silver halide has not been sufficient to improve the storage stability of the silver halide light-sensitive material.

Further, regarding photographic paper, Japanese Patent Application Laid-Open No. Sho 52-65423
JP-B-58-43730 and JP-B-58-43730 propose to remove the adverse effect on photographic properties due to decomposition of the cationic electrolyte and paper additives, respectively. Even when used as a body, the storage stability of the silver halide photographic material could not be improved at all, and it was clarified that deterioration of the storage stability was caused by a mechanism completely different from the mechanism described in these specifications.

As described above, a support for a resin-coated paper type photographic material in which the surface on which the photographic image forming layer is provided of the base paper mainly composed of natural pulp is coated with a thermoplastic resin layer, particularly a polyethylene resin layer. There is no known method for improving the sharpness of a printed image without impairing the other properties of the support and the moldability during the production of the support, and also from a cooling roll during the production of a resin-coated paper-type support. No known mechanism or cause of the occurrence of peeling unevenness or uneven peeling, or deterioration of the storage stability of the silver halide photographic material having the support is known.

[0021]

Accordingly, a first object of the present invention is to provide a printed image having a photographic image forming layer on which a base paper surface is coated with a thermoplastic resin layer containing a titanium dioxide pigment. And the storage stability with respect to the silver halide photosensitive layer is remarkably improved, and the releasability from the cooling roll during the production of the support is remarkably improved so that there is no occurrence of non-uniform release, and therefore, the gloss is excellent. To provide a support for a resin-coated paper-type photographic material capable of providing an improved photographic material. A second object of the present invention is to provide a photographic image forming layer on which a base paper surface is formed of a thermoplastic resin layer containing a titanium dioxide pigment.
It is coated at a production speed of 00 m / min or more, particularly 150 m / min or more, and therefore has good productivity and economical efficiency, and has a remarkably improved releasability from a chill roll to prevent occurrence of peeling unevenness. Therefore, it is possible to provide a support for a resin-coated paper-type photographic material which can provide a photographic material having excellent glossiness, has high sharpness of a printed image, and has remarkably improved storage stability with respect to a silver halide photosensitive layer. That is. Other objects of the present invention will become clear from the description of the following specification.

[0022]

Means for Solving the Problems As a result of intensive studies to solve the above-mentioned problems, the present inventor has found that paper containing natural pulp as a main component is used as a substrate and one of the paper substrates on which a photographic image forming layer is provided. In a photographic material support having a surface coated with a thermoplastic resin (A) layer, the thermoplastic resin (A) layer contains at least a thermoplastic resin and a titanium dioxide pigment, and the titanium dioxide pigment is spray-dried. A support for photographic materials, characterized in that the apparent density (static method) required according to JIS K 5101-1991 is 0.32 g / cm ³ or more. It has been found that the object of the present invention is achieved by the above.

An object of the present invention is to provide a support for a photographic material, in which the surface of a paper substrate on which a photographic image forming layer of a natural pulp as a main component is provided is coated with a thermoplastic resin (A) layer. The thermoplastic resin (A) layer contains at least a thermoplastic resin and a titanium dioxide pigment, and is manufactured by spray drying as a titanium dioxide pigment, and is required in accordance with JIS K 5101-1991. It has been found that by using a material having an apparent density (stationary method) of 0.32 g / cm ³ or more, it can be achieved synergistically. Further, the object of the present invention is to provide a titanium dioxide pigment whose surface is calculated as 0.25% by weight to 1.5% by weight, particularly 0.35% by weight, calculated as anhydrous metal oxide per titanium dioxide.
It has been found that this can be achieved remarkably by using 1.25% by weight of a specific hydrated metal oxide, particularly one which has been surface-treated with at least hydrous aluminum hydroxide. Also,
An object of the present invention is to use a titanium dioxide pigment having a particle diameter of 0.110 to 0.150 μm represented by a number average diameter in a directional measurement by an electron microscope,
It has been found that it is achieved remarkably. Further, the object of the present invention has been found to be more remarkably achieved by using an anatase structure produced by an external seed method as a titanium dioxide pigment, and has reached the present invention.

Further, spray drying of a titanium dioxide pigment is disclosed in JP-A-3-50120, but it is simply spray-dried in a surface resin layer of a support for a resin-coated paper type photographic material. The effect of the present invention is not obtained at all even if the titanium dioxide pigment produced is contained, and the titanium dioxide pigment is produced by spray drying.
In addition, the object of the present invention is synergistically achieved by including a material having an apparent density (static standing method) of 0.32 g / cm ³ or more in the surface resin layer in accordance with JIS K 5101-1991. That is, they have reached the present invention.

The base paper surface of the photographic material support of the present invention on the side on which the photographic image forming layer is provided is coated with a thermoplastic resin layer containing at least the thermoplastic resin (A) and the titanium dioxide pigment of the present invention. Those thermoplastic resins (A)
As a polyolefin-based resin, polyester-based resin, polycarbonate-based resin, polyamide-based resin or a mixture thereof, polyolefin-based resin, polyester-based resin or a mixture thereof is more preferable from the viewpoint of melt-extrusion coating properties, and polyethylene-based resin is preferable. Resins are particularly preferred. As the polyethylene resin particularly preferably used in the practice of the present invention, low-density polyethylene resin, medium-density polyethylene resin, high-density polyethylene resin, linear low-density polyethylene resin, ethylene and propylene, and α-olefin such as butylene So-called carboxy-modified polyethylene resin, which is a copolymer or a copolymer or a graft copolymer of ethylene and acrylic acid, acrylic acid ethyl ester, maleic anhydride, etc., or an autoclave type reactor, a tubular type reactor, etc. Polyethylene resin produced by high pressure radical polymerization method, polyethylene resin produced by polymerization using metallocene polymerization catalyst, polyethylene resin produced by polymerization using metal catalyst other than metallocene using Ziegler method, Philip method, etc. A mixture of various densities and -Flow rate (hereinafter, abbreviated simply as MFR to a melt flow rate specified by JIS K 6760), the molecular weight, can be used those having a molecular weight distribution, typically, density of 0.90~0.97g / cm ³ Range, MFR is 0.1g / 10min ~
50 g / 10 min, preferably 0.3 g / 10 min to 40 g MFR
Those having a range of / 10 minutes can be advantageously used alone or as a mixture. When the surface resin layer has a multilayer structure, the outermost layer resin has an MFR of, for example, 5 g / 10 min to 20 g / 10 min, and the lower layer resin has, for example, an MFR of 2 g / 10 min to 1 gm.
It is also possible to use a resin having another property and constitution, such as using a resin of 0 g / 10 min. Further, a multilayer structure in which only the outermost layer is a resin layer containing the specific titanium dioxide pigment of the present invention may be used.

The polyester resins used in the practice of the present invention include polyethylene terephthalate resin, polybutylene terephthalate resin, polyester biodegradable resin and the like, and mixtures thereof. Among them, copolymerized polyethylene terephthalate resin is preferred from the viewpoint of melt extrusion coating properties. As a specific representative example, a copolyester resin manufactured by Eastman Chemical Japan Co., Ltd. [trade name: KODA PETG 676]
3: Density: 1.27 g / cm ³ , glass transition point: about 81 ° C., average molecular weight (Mn): about 26,000] or thermoplastic polyester resin [trade name: Kodapak-PET 298L]
B].

It is preferable that the surface of the support for the photographic material in the present invention opposite to the side on which the thermoplastic resin (A) layer is provided is coated with a resin (B) layer capable of forming a film. As those film-forming resins (B),
Polyolefin-based resins, polyester-based resins, polycarbonate-based resins, thermoplastic resins such as polyamide-based resins or mixtures thereof are preferred, and polyolefin-based resins, polyester-based resins or mixtures thereof are more preferred from the viewpoint of melt extrusion coating properties, Polyethylene resins are particularly preferred. In addition, Japanese Patent Publication 60-17104
May be covered with an electron beam curable resin layer described or exemplified in Japanese Patent Application Publication No.

The titanium dioxide pigment used in the practice of the present invention is manufactured by spray drying and has an apparent density (static method) required according to JIS K 5101-1991 [hereinafter referred to as JIS. The term apparent density (static method) required in accordance with K 5101-1991 is
If the apparent density is simply 0.32 g / cm ³ or more, any of rutile structure, anatase structure, chlorine method and sulfuric acid method can be used. Describing these specific production methods, in the case of the chlorine method, titanium dioxide particles are formed by vapor-phase oxidative decomposition of titanium tetrachloride at a high temperature, and a rutile structure is generally easily obtained. In the case of the sulfuric acid method, hydrous titanium oxide is formed by hydrolysis of an aqueous solution of titanyl sulfate and calcined to develop its pigmentary properties. In the case of the sulfuric acid method, both those having an anatase structure and those having a rutile structure can be obtained. Sometimes, a metal compound such as a zinc compound for promoting the formation of a rutile structure is allowed to coexist. The product resulting from calcination or oxidation will be referred to hereinafter as titanium dioxide clinker. Titanium dioxide clinker is dry-pulverized by a centrifugal roller mill (mainly a Raymond mill), and the pulverized material is suspended in water to form a titanium dioxide slurry. Wet classification is performed using a machine or / and through a vibrating double deck screen (325 mesh US standard screen), and the substantially coarser carbon dioxide, hereinafter referred to as fines. Make titanium dioxide slurry without titanium. The fine particles still in the form of a slurry from which the coarse particles have been removed are preferably surface-treated with a hydrated metal oxide in a reaction tank equipped with a stirrer. After the surface treatment, the mixture is preferably filtered and washed with a filter press. After washing with water, the titanium dioxide cake is taken out of the filter press, formed into a titanium dioxide slurry in a water tank, and then spray-dried by a spray-drying device. Further, fine pulverization is performed by an impact pulverizer or / and a fluid energy mill, preferably a steam mill, to produce a titanium dioxide pigment. As the fluid energy, one equipped with a bag filter is preferable.

The titanium dioxide pigment used in the practice of the present invention has been produced by spray drying. As a spray drying device, in principle, titanium dioxide slurry is sprayed through a two-fluid nozzle into an evaporating tube on a hot air flow path,
At the same time as entraining the atomized titanium dioxide slurry with hot air heated by an electric heater, a steam heater, etc., the evaporation area is remarkably increased, and therefore water is evaporated in a short time to form dry fine powder, Various devices can be used as long as the device is a device for guiding the fine powder to a cyclone (collection unit). Further, a device using an ultrasonic wave as a spraying device or a device using a microwave as a drying device can be used. After spray drying, additional drying can be performed.

The titanium dioxide pigment used in the practice of the present invention is manufactured by spray drying and has an apparent density of 0.32 g / cm ³ or more. The apparent density is 0.35 g from the viewpoint of remarkably improving the sharpness), remarkably improving the storage stability of the silver halide photographic material, and remarkably improving the releasability from the cooling roll during the production of the resin-coated paper. / cm ³ or more is preferable, and 0.38 g / cm ³ or more is particularly preferable.

The titanium dioxide pigment used in the practice of the present invention, which is manufactured by spray drying and has an apparent density of 0.32 g / cm ³ or more, is specifically described in the following (1) to (1).
The study by the present inventors has clarified that the method described in (5) is preferably obtained by combining two or more, and more preferably three or more, of the following methods.

(1) When producing a titanium dioxide pigment,
Optimize spray drying of titanium dioxide slurry. In order to optimize the spray drying conditions of the titanium dioxide slurry, it can be appropriately determined according to the type of the spray drying apparatus. Specifically, the apparent density is 0.32 g / cm ³ or more, and the particle size is uniform and fine. The conditions such as the amount of sprayed titanium dioxide slurry, the spray pressure, the size of the sprayed droplets, the temperature of hot air, and the drying time can be optimized so as to obtain a dry fine powder.

(2) As a titanium dioxide pigment, the particle surface has at least 0.25% to 1.5% by weight, calculated as anhydrous metal oxide per titanium dioxide, of at least an aluminum atom and containing silicon dioxide. Used is one treated with 0.4% by weight or less (including 0) of a hydrated metal oxide. If the treatment amount of the titanium dioxide surface is less than 0.25% by weight, the apparent density of the titanium dioxide pigment tends to decrease, and the support for a resin-coated paper type photographic material containing the titanium dioxide pigment in a surface resin layer. Means that the sharpness of the printed image deteriorates, the storage stability with respect to the silver halide photosensitive layer deteriorates, and the peelability from the cooling roll during the production of the resin-coated paper deteriorates, thus effectively preventing the occurrence of peeling unevenness. I can't do it. On the other hand, when the processing amount is more than 1.5% by weight, the apparent density of the titanium dioxide pigment tends to gradually decrease as the amount increases, and the resin-coated paper type photographic material containing the titanium dioxide pigment in the surface resin layer is used. The support is insufficient in the sharpness and preservability of the printed image, and the releasability from the cooling roll during the production of the resin-coated paper is also deteriorated, so that the occurrence of uneven peeling cannot be effectively prevented. It is a problem. The preferred range of the treatment amount is in the range of 0.35% by weight to 1.25% by weight, particularly preferably 0.5% by weight to 1.25% by weight, calculated in the form of anhydrous metal oxide with respect to titanium dioxide. %
Range. The hydrated metal oxide containing at least aluminum atoms and having a silicon dioxide content of 0.4% by weight or less (including 0) is preferably surface-treated with hydrated aluminum hydroxide. 0.4% by weight or less, preferably 0.25% by weight
Other hydrous metal oxides such as less than 1.5% by weight or less of hydrous titanium oxide in total amount of anhydrous metal oxide can be used.

(3) As the titanium dioxide pigment, a pigment having a particle diameter in the range of 0.110 μm to 0.150 μm expressed by a number average diameter as measured by a fixed direction using an electron microscope is used. In this specification, the number average diameter in the directional measurement with an electron microscope (the term of the number average diameter in the directional measurement with an electron microscope is sometimes simply abbreviated to the number average diameter hereinafter) is titanium dioxide. This is a value obtained by averaging the lengths of the pigment particles obtained by a fixed direction measurement using an electron microscope for 1000 particles, and is expressed in μm. When the number average diameter of the titanium dioxide pigment is 0.110 μm or less, the apparent density of the titanium dioxide pigment tends to decrease as the number average diameter decreases, and a resin containing the titanium dioxide pigment in the surface resin layer The coated paper type photographic material support tends to have poor print image sharpness and storage stability with respect to the silver halide photosensitive layer, and tends to have poor peelability from a cooling roll during production of resin-coated paper. Uneven peeling cannot be effectively prevented. On the other hand, a support for a resin-coated paper-type image material containing a titanium dioxide pigment larger than 0.150 μm in a surface resin layer tends to have a considerably low sharpness of a printed image.

As a result of various studies by the present inventors, titanium dioxide having a number average diameter of 0.110 μm to 0.150 μm is used in combination with spray drying to obtain a titanium dioxide pigment finally obtained due to their synergistic effect. It was found that the apparent density of the printed image could be increased, and the sharpness of the printed image, the preservability with respect to the silver halide photosensitive layer, and the releasability from the cooling roll during the production of the resin-coated paper could be remarkably improved. Accordingly, the titanium dioxide pigment used in the practice of the present invention has a number average diameter of 0.110 μm to 0.1 μm.
A range of 150 μm is preferable, and 0.115 μm to 0.1.
Those having a range of 35 μm are particularly preferred.

(4) Titanium dioxide pigments produced by the external seed method, particularly preferably those produced by the external seed method and having a number average diameter of 0.110 μm to 0.150
A titanium dioxide pigment having an anatase structure in the range of μm is used. Here, the titanium dioxide pigment having an anatase structure (hereinafter, may be simply referred to as an anatase-type titanium dioxide pigment) is 90% by weight or more in its crystal structure.
Preferably, 95% by weight or more has an anatase structure. By using the above anatase type titanium dioxide pigment, a support for photographic materials having high sharpness of a printed image and excellent whiteness can be obtained.

Conventionally, a method for producing titanium dioxide is to crystallize iron sulfate from a solution obtained by treating ilmenite with sulfuric acid.
When the titanyl sulfate solution separated therefrom is boiled and hydrolyzed, the titanyl sulfate solution is added to warm water, and titanium hydroxide is precipitated to produce seeds. It is difficult to control the production conditions such as the concentration of the titanyl solution, the temperature and time during the hydrolysis, and the apparent density of the finally obtained titanium dioxide pigment tends to be low, particularly in the anatase type titanium dioxide pigment. Met. On the other hand, the titanium dioxide pigment produced by the external seed method referred to in the present invention is a water solution of titanium prepared by neutralizing titanyl sulfate or titanium tetrachloride when boiling a titanyl sulfate solution for hydrolysis. A titanium dioxide pigment produced by a method of adding an oxide as a seed. In the case of the titanium dioxide pigment produced by the external seed method referred to in the present invention, there is an advantage that a titanium dioxide having a desired size and a uniform particle size distribution can be produced freely, and furthermore, the present inventors As a result of the study, by using the external seed method and spray drying together,
Due to their synergistic effect, the apparent density of the titanium dioxide pigment finally obtained can be increased. In particular, the improvement of the apparent density is achieved when the number average diameter is 0.110 μm to 0.10 μm.
It turned out to be remarkable in an anatase type titanium dioxide pigment having a size of 150 μm.

(5) As the titanium dioxide pigment, it is preferable to use a so-called organic surface-treated titanium dioxide pigment whose surface is treated with an organic substance. Specifically, a silane coupling agent, an organopolysiloxane compound, an alkanolamine compound, etc. described or exemplified in JP-B-60-3430 and JP-B-61-26652, 0.05% by weight based on titanium dioxide. It is preferable to use a titanium dioxide pigment having a surface treatment of about 4.0% by weight. When the surface treatment amount is less than 0.05% by weight, the effect of the organic surface treatment is small, and when the surface treatment amount is more than 4.0% by weight, the releasability from the cooling roll at the time of producing the resin-coated paper is deteriorated, which is another problem. The problem is that the adhesiveness between the surface resin layer and the photographic image forming layer, particularly the film-forming property during the development processing of the photographic material, is deteriorated.

As a result of various studies by the present inventors, a preferable amount of the organic surface treatment is in a range of 0.05% by weight to 4.0% by weight based on titanium dioxide. In combination, the apparent density of the finally obtained titanium dioxide pigment can be increased due to the synergistic effect thereof, and the sharpness of the printed image, the storage stability for the silver halide photosensitive layer, and the production of resin-coated paper It has been found that the releasability from the cooling roll can be remarkably improved. The most preferable surface treatment amount is in the range of 0.3% by weight to 2.0% by weight based on titanium dioxide.

As a result of various studies conducted by the present inventors, a preferred embodiment of the present invention is to provide a titanium dioxide pigment to be contained in a surface resin layer of a support for a resin-coated paper type photographic material. 0.25% to 1.5% by weight, more preferably 0.35% to 1.25% by weight, calculated in the form of metal oxide, treated with a hydrated metal oxide containing at least aluminum atoms. And produced by spray drying, with an apparent density of 0.35 g / cm ³
That is, the above-mentioned titanium dioxide pigment is used.

In a further preferred embodiment of the present invention, a titanium dioxide pigment to be contained in a surface resin layer of a support for a resin-coated paper type photographic material, the surface of which is in the form of an anhydrous metal oxide per titanium dioxide. 0.25% to 1.5% by weight, even more preferably 0.35% to 1.25% by weight, of a hydrous metal oxide containing at least aluminum atoms, calculated and number averaged A titanium dioxide pigment having a diameter of 0.110 μm to 0.150 μm and produced by spray drying and having an apparent density of 0.35 g / cm ³ or more is used.

In a further preferred embodiment of the present invention, a titanium dioxide pigment to be contained in a surface resin layer of a support for a resin-coated paper type photographic material, the surface of which is in the form of an anhydrous metal oxide per titanium dioxide. 0.25% to 1.5% by weight, even more preferably 0.35% to 1.25% by weight, of a hydrous metal oxide containing at least aluminum atoms, calculated and organic surface Treated and having a number average diameter of 0.110 μm to 0.150
The use of a titanium dioxide pigment having an apparent density of 0.38 g / cm ³ or more, which is produced by spray-drying, has a diameter of μm.

In a preferred embodiment of the present invention, a titanium dioxide pigment to be contained in a surface resin layer of a support for a resin-coated paper type photographic material, the surface of which is calculated in the form of an anhydrous metal oxide per titanium dioxide. 0.25% to 1.5% by weight, more preferably 0.35% by weight
1.25% by weight of a hydrous metal oxide containing at least aluminum atoms and having a number average diameter of 0.1
The use of an anatase type titanium dioxide pigment having an apparent density of 0.35 g / cm ³ or more, which is from 10 μm to 0.150 μm, produced by the external seed method, and further produced by spray drying.

In a further preferred embodiment of the present invention, a titanium dioxide pigment to be contained in a surface resin layer of a support for a resin-coated paper type photographic material, the surface of which is in the form of an anhydrous metal oxide per titanium dioxide. 0.25% to 1.5% by weight, even more preferably 0.35% to 1.25% by weight, of a hydrous metal oxide containing at least aluminum atoms, calculated and organic surface calculated Treated and having a number average diameter of 0.110 μm to 0.150
The use of an anatase type titanium dioxide pigment having an apparent density of 0.35 g / cm ³ or more, which is produced by spray-drying, has a diameter of μm.

In a further preferred embodiment of the present invention, as a titanium dioxide pigment to be contained in a surface resin layer of a support for a resin-coated paper type photographic material, the surface of the titanium dioxide pigment may be in the form of an anhydrous metal oxide per titanium dioxide. 0.3
5% to 1.25% by weight, particularly preferably 0.35% to 1.25% by weight, of a hydrous metal oxide containing at least aluminum atoms and of an organic surface treatment, and Average diameter is 0.110 μm to 0.15
0 μm, further produced by the external seed method, and further produced by spray drying, with an apparent density of 0.38 g / c.
The use of an anatase-type titanium dioxide pigment having an m ³ or more.

The titanium dioxide pigment preferably used in the practice of the present invention has a particle surface whose surface is calculated to be from 0.25% to 1.5% by weight of at least aluminum atom per titanium dioxide in the form of anhydrous metal oxide. And produced by treating with a silicon dioxide content of 0.4% by weight or less (including 0) of a hydrated metal oxide. As a specific example of the method of treating the surface of the titanium dioxide particles with the hydrated metal oxide, a titanium dioxide slurry, preferably fine p
After adjusting H to 5 or more, preferably 6 or more, particularly preferably around 7, a water-soluble aluminum salt and, if necessary, other water-soluble metal salts and water-soluble silicon compounds were added to the titanium dioxide slurry, and By changing the pH,
The hardly soluble hydrous aluminum hydroxide and, if necessary, other hardly soluble hydrated oxides and / or hardly soluble metal compounds can be precipitated on titanium dioxide particles for surface treatment. For example, to describe a typical method in the case of performing a surface treatment in a reaction tank equipped with a stirrer, a titanium dioxide slurry, preferably fine sodium hydroxide, an aqueous solution of a water-soluble alkali such as potassium hydroxide, Adjust the pH to 7.0 ± 1.0. To the pH-adjusted titanium dioxide slurry, an aluminate such as alkali aluminate, and if necessary, an aqueous solution of a water-soluble alkali such as sodium hydroxide and potassium hydroxide are added. In order to reduce the water content and to precipitate the hydrous aluminum hydroxide on the surface of the titanium dioxide particles, the surface is treated by adding an aqueous solution of a mineral acid such as sulfuric acid or hydrochloric acid or a salt exhibiting an acidic reaction. The pH of the titanium dioxide slurry after the surface treatment is usually 7.0 ±
It is in the range of 1.0. Among the alkali aluminates, sodium aluminate is particularly useful. Further, in addition to the aluminate, the surface can be treated with another inorganic surface treating agent. In this case, it can be added at any stage before, during or after the addition of the aluminate, but it is particularly advantageous to add it before the addition of the aluminate. Inorganic surface treatment agents other than aluminates used for these surface treatments include, as silicon compounds, alkali silicates, silicon tetrachloride, etc .; titanium compounds, such as titanium tetrachloride, zirconium, zinc, magnesium, manganese, etc. Various compounds such as metal compounds and phosphoric acid compounds can be used. Further, as a method of treating the surface of titanium dioxide particles with a hydrated metal oxide, JP-A-3-2757
No. 68, JP-A-5-286721 and the like.

The titanium dioxide pigment preferably used in the practice of the present invention has a number average diameter of 0.110 μm to 0.15.
It is 0 μm. Number average diameter is 0.110 μm
Titanium dioxide pigments of ~ 0.150 [mu] m can be obtained by manufacturing under their predetermined manufacturing conditions. The production conditions of the titanium dioxide pigment, particularly the calcination temperature, the calcination time, and the calcination conditions such as the type and the amount of the inorganic compound to be present at the time of calcination, for example, the inorganic compounds described in JP-B-48-18718 or the exemplified compounds and their combined compounds Can be determined by measuring the number average diameter of the titanium dioxide pigment produced under a series of combined experimental conditions. At that time, as the firing conditions for increasing the number average diameter, a high firing temperature, a long firing time, and a small amount of the inorganic compound to be present during firing are typical conditions. Typical conditions include a low firing temperature, a short firing time, and a large amount of an inorganic compound to be present during firing. As the firing conditions of the titanium dioxide pigment used in the practice of the present invention, the firing temperature is 800 ° C. to 1100 ° C., the firing time is 15 minutes to 5 hours, and the amount of the inorganic compound is as follows.
Combination conditions in the range from 0.2% to 5% by weight per titanium dioxide, calculated in the form of inorganic oxide, are particularly preferred.

The titanium dioxide pigment preferably used in the practice of the present invention has been subjected to an organic surface treatment. Preferred organic surface treatment agents include γ-chloropropyltrimethoxysilane, vinyltrimethoxysilane,
Methyltrimethoxysilane, vinyltriethoxysilane, vinyltris (2-methoxyethoxy) silane, γ
-Methacryloxypropyltrimethoxysilane, γ-methacryloxypropyltris (2-methoxyethoxy)
Silane, β- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-aminopropyltriethoxysilane, N-β- (aminoethyl) -γ-aminopropyltrimethoxy Silanes, silane coupling agents such as γ-ureidopropyltriethoxysilane, alkylpolysiloxanes, alkylarylpolysiloxanes, alkylhydrogenpolysiloxanes such as dimethylpolysiloxane, dimethylphenylpolysiloxane, and organopolysiloxanes such as methylhydrogenpolysiloxane. Siloxane compounds, polyether-modified siloxanes described in JP-B-4-34139, zircoaluminate coupling agents described in JP-B-4-76463, triethanolamine, triisopropanolamine, etc. Alkanolamine compound, trimethylol ethane, polyhydric alcohol compounds such as trimethylolpropane, it may be mentioned an amide compound and the like and mixtures thereof described in JP Kokoku 4-76464. The timing of the organic surface treatment is preferably performed by adding an organic surface treating agent to the titanium dioxide slurry at an arbitrary stage before spray-drying the titanium dioxide slurry. Organic surface treatment agents include water, methanol, ethanol,
It may be dissolved and diluted in an appropriate solvent such as acetone or the like, or may be added without dilution.

The titanium dioxide pigment used in the practice of the present invention is suitably washed and finely pulverized as described in JP-B-1-38292 to obtain a suspension having an electric conductivity of 55 μmho.
(ΜΩ ^{- 1)} / cm or less, particularly 50μmho (μΩ ^-1) / cm or less are preferred ones, as described in JP Matatoku Sho 63-4489, titanium dioxide pigment under the conditions of 2 hours at 110 ° C. Is preferably 0.35% by weight or less.

As a method for incorporating the titanium dioxide pigment used in the practice of the present invention into the surface resin layer for coating the base paper, a so-called masterbatch in which the titanium dioxide pigment is previously contained at a certain concentration in a thermoplastic resin is used. Prepare and use it by diluting and mixing it with a thermoplastic resin for dilution to a desired ratio, or use a so-called compound in which a desired composition ratio of titanium dioxide pigment is contained in a thermoplastic resin. However, it is preferable to incorporate them as a master batch. To prepare these master batches and compounds, a Banbury mixer, a kneader, an extruder for kneading, a roll kneading machine, a kneading machine disclosed in JP-A-6-110158, and the like are usually used. These kneaders may be used in combination of two or more.

The masterbatch of titanium dioxide pigment preferably used in the practice of the present invention has an oxidation induction period of 3 times.
It is preferably from 0 to 900 seconds, and from 40 to 600 seconds.
Seconds are more preferable, and those for 50 to 350 seconds are particularly preferable. The oxidation induction period referred to here means that a sample of 10 mg was set in a differential scanning calorimeter in an aluminum tray, nitrogen gas was passed through, and the temperature was rapidly increased after 5 minutes.
Fix at 0 ° C. After 5 minutes, the nitrogen gas is switched to the air gas to start the measurement, and at least the change in the calorific value with the lapse of time until the heat generation peak is charted by automatic recording. Thus, the time from the start of measurement (at the time of switching to air gas) to the intersection of the tangent of the calorific change curve from the start of measurement to the initial exothermic reaction and the tangent of the caloric change curve from the initial exothermic reaction to the exothermic peak was determined. This time is defined as the oxidation induction period (second).

In preparing the masterbatch or compound of the titanium dioxide pigment, the preparation is preferably carried out in the presence of a suitable amount of a suitable lubricant. Specifically, as the lubricant, it is preferable to use a fatty acid metal salt such as zinc stearate, calcium stearate, aluminum stearate, magnesium stearate, zinc palmitate, zinc myristate, calcium palmitate, and particularly zinc stearate or / And magnesium stearate are preferred. Further, as the abundance, a range of 0.1% by weight to 20% by weight based on the titanium dioxide pigment is useful,
A range of 1% to 7.5% by weight is preferred.

In preparing a master batch or compound of the titanium dioxide pigment, it is preferable to prepare the titanium dioxide pigment in the presence of an appropriate amount of an appropriate antioxidant. In particular,
Hindered phenolic antioxidants described or exemplified in JP-A-1-105245, phosphorus-based antioxidants described or exemplified in JP-A-55-142335, and various antioxidants such as hindered amines and sulfur-based ones It is preferred that the agent be present in an appropriate amount. The amount of antioxidant present during the preparation of the titanium dioxide masterbatch or compound is 50
The range is preferably from ppm to 1500 ppm, but from 120 ppm to 9 ppm.
A range of 50 ppm is more preferred.

Examples of the hindered phenolic antioxidant preferably present at the time of preparing a masterbatch or a compound of titanium dioxide pigment include 1,3,5-trimethyl-2,4,6-tris (3,3 5
-Di-tert-butyl-4-hydroxybenzyl) benzene, tetrakis [methylene (3,5-di-tert-butyl-4-hydroxy-hydrocinnamate)] methane, octadecyl-3,5-di-tert-butyl -4-Hydroxy-hydrocinnamate, 2,2 ', 2 "-tris [(3,
5-di-tert-butyl-4-hydroxyphenyl) propionyloxy] ethyl isocyanurate, 1,3,5-
Tris (4-tert-butyl-3-hydroxy-2,6-
Di-methylbenzyl) isocyanurate, tetrakis (2,4-di-tert-butylphenyl) 4,4′-biphenylenediphosphite, 4,4′-thiobis- (6-
tert-butyl-0-cresol), 2,2′-thiobis-
(6-tert-butyl-4-methylphenol), tris- (2-methyl-4-hydroxy-5-tert-butylphenyl) butane, 2,2′-methylene-bis- (4-methyl-6-tert) -Butylphenol), 4,4'-methylene-bis- (2,6-di-tert-butylphenol),
4'-butylidenebis- (3-methyl-6-tert-butylphenol), 2,6-di-tert-butyl-4-methylphenol, 4-hydroxy-methyl-2,6-di-t
ert-butylphenol, 2,6-di-tert-butyl-4
-N-butylphenol and the like. Further, two or more antioxidants may be used in combination depending on the characteristics of the antioxidant.

As a method for allowing an antioxidant to be present at the time of preparing a master batch or a compound of titanium dioxide pigment, a so-called compound in which an antioxidant is previously contained in a thermoplastic resin to be used may be used. Alternatively, an appropriate amount of a resin containing a relatively high concentration of an antioxidant may be used, or the antioxidant may be added when a master batch or compound is produced by a kneader. Further, depending on the type and content of the antioxidant used, the above methods may be appropriately combined.

As a method of coating the resin layer on the base paper surface of the support for photographic material in the present invention, the resin layer is cast on a running base paper from a slit die into a film by using a melt extruder. It is preferable to coat by a so-called melt extrusion coating method. At that time, the temperature of the molten film is preferably 270 to 330 ° C. In the case of a polyester resin layer, 220 to
Preferably it is 300 ° C. As the slit die, a flat die such as a T-type die, an L-type die and a fishtail type die is preferable, and the slit opening diameter is 0.1 to 2 mm.
It is desirable that Further, it is preferable to perform an activation treatment such as a corona discharge treatment or a flame treatment on the base paper before coating the resin layer on the base paper. Further, as described in JP-B-61-42254, a resin layer may be coated on a running base paper after spraying an ozone-containing gas onto a molten resin surface in contact with the base paper. Further, the front and back resin layers are sequentially, preferably continuously, extrusion-coated, and are preferably coated on the base paper by a so-called tandem extrusion coating method, and if necessary, the front and back resin layers are It is preferable to be coated by a multi-layer extrusion coating method in which the composition has two or more layers. The resin layer surface is glossy,
It can be processed to a fine rough surface, mat surface or silk surface described in -19732. In particular, the effects of the present invention are remarkable in a photographic material support in which the surface resin layer has a glossy surface or a finely rough surface.

The coating thickness of the surface resin layer of the photographic material support in the present invention is usefully in the range of 8 to 100 μm, preferably in the range of 12 to 60 μm, and more preferably in the range of 18 to 40 μm.
The range of μm is particularly preferred. In addition, the base paper surface on the back side is coated with a back resin layer containing a resin capable of forming a film as a main component, and the resin is particularly preferably a polyethylene-based resin. It is preferable to set appropriately within a range where curl balance is obtained. Generally, a range of 8 to 100 μm is useful, but preferably
It is in the range of 2 to 60 μm.

The surface resin layer of the photographic material support of the present invention and, if necessary, the back resin layer contain various additives in addition to the above-mentioned titanium dioxide pigment, fatty acid metal salt and antioxidant. I can do it. In addition to titanium dioxide pigments, white pigments such as zinc oxide, talc, calcium carbonate, etc., as release agents, fatty acid amides such as stearamide, arachidic amide, and blue-based pigments such as cobalt blue, ultramarine, celian blue, and phthalocyanine blue Pigments and dyes, magenta pigments and dyes such as cobalt violet, fast violet and manganese violet, quinacridone red pigments described or exemplified in Japanese Patent Publication No. 4-2175, and described or exemplified in JP-A-2-254440 Various additives such as a fluorescent brightener and an ultraviolet absorber can be appropriately combined and contained. These additives are preferably incorporated in the masterbatch or compound of the titanium dioxide pigment used in the practice of the present invention, or as a separate resin masterbatch or compound.

The base paper used in the practice of the present invention is preferably a natural pulp paper whose main component is ordinary natural pulp. Further, a mixed paper made of natural pulp as a main component and synthetic pulp and synthetic fiber may be used. Such natural pulp is described or exemplified in JP-A-58-37642, JP-A-60-67940, JP-A-60-69649, JP-A-61-35442 and the like. It is advantageous to use such appropriately selected natural pulp. Natural pulp was subjected to normal bleaching treatment of chlorine, hypochlorite, chlorine dioxide bleaching and alkali extraction or alkali treatment and, if necessary, oxidative bleaching treatment with hydrogen peroxide, oxygen, etc., and a combination treatment thereof Softwood pulp, hardwood pulp,
Wood pulp of softwood mixed hardwood pulp is advantageously used, and various types such as kraft pulp, sulfite pulp, and soda pulp can be used.

The base paper mainly composed of natural pulp preferably used in the practice of the present invention may contain various additives at the time of preparing the stock slurry. As a sizing agent, fatty acid metal salts, fatty acids or a combination thereof, an alkyl ketene dimer emulsion described or exemplified in JP-B-62-7534, an epoxidized higher fatty acid amide or a combination thereof, an alkenyl or alkyl succinic anhydride emulsion Products, rosin derivatives, etc.
Anionic, cationic or amphoteric polyacrylamide, polyvinyl alcohol, cationized starch, vegetable galactomannan, etc., as a wet paper strength enhancer, polyamine polyamide epichlorohydrin resin, etc., as a filler,
Clay, kaolin, calcium carbonate, titanium oxide, etc., water-soluble aluminum salts such as aluminum chloride, bansulfate, etc. as fixing agents, caustic soda, sodium carbonate, sulfuric acid, etc. as pH regulators, and others JP-A-63-204251 Publication, coloring pigments described or exemplified in JP-A 1-266537, etc.,
It is advantageous to incorporate color dyes, optical brighteners and the like in appropriate combinations.

Further, in or on a base paper mainly composed of natural pulp preferably used in the practice of the present invention,
A composition comprising various water-soluble polymers or hydrophilic colloids or latex, an antistatic agent and additives can be contained or applied by coating such as size press or tab size press or blade coating or air knife coating. it can. As a water-soluble polymer or hydrophilic colloid, starch-based polymers described or exemplified in JP-A-1-266537, polyvinyl alcohol-based polymers, gelatin-based polymers, polyacrylamide-based polymers, cellulose-based polymers, etc., as emulsions and latexes, Petroleum resin emulsion, JP 55-4
No. 027, emulsion or latex of a copolymer containing at least ethylene and acrylic acid (or methacrylic acid) as described or exemplified in JP-A-1-80538, styrene-butadiene-based, styrene-acryl-based, Vinyl acetate-acrylic, ethylene-vinyl acetate-based, butadiene-methyl methacrylate-based copolymers and emulsions or latexes of carboxy-modified copolymers thereof, as antistatic agents, sodium chloride, alkali metal salts such as potassium chloride, Calcium chloride, alkaline earth metal salts such as barium chloride, colloidal metal oxides such as colloidal silica, organic antistatic agents such as polystyrene sulfonate, pigments such as clay,
Appropriate combinations of additives such as kaolin, calcium carbonate, talc, barium sulfate, titanium oxide, etc., as pH adjusters, such as hydrochloric acid, phosphoric acid, citric acid, caustic soda, and the above-mentioned coloring pigments, coloring dyes, optical brighteners It is advantageous to incorporate them.

The thickness of the base paper used in the practice of the present invention is not particularly limited, but the basis weight is 20 to 250 g / g.
m ² is preferred.

The base paper used in the practice of the present invention includes a film thickness unevenness index Rpy defined in the papermaking direction defined below.
Is preferably 250 mV or less, more preferably 200 mV or less, and most preferably 150 mV or less.
The film thickness non-uniformity index Rpy referred to here is a value obtained by using a film thickness measuring device that moves a sample between two spherical styluses and measures a thickness variation of the sample as an electric signal through an electronic micrometer. ± 1 sensitivity range
Under the condition of 5 μm / ± 3V, the sample was scanned at a constant speed of 1.5 m / min after the zero point adjustment in the papermaking direction to measure the thickness variation of the sample in the papermaking direction. Using an analyzer, a fast Fourier transform is performed using a Hanning window as a time window, and a power spectrum (unit: mV ² ) obtained by averaging 128 times of integration is obtained.
A value (unit: mV) obtained by summing power values in a frequency range of 25 Hz, multiplying by 2/3, and multiplying by 1/2.
It is.

As a method for producing a base paper having a thickness unevenness index Rpy of 250 mV or less, which is preferably used in the practice of the present invention, concretely, hardwood pulp which is short fiber and easily smooth is 30% by weight or more. Preferably, it is used in an amount of 50% by weight or more, and beaten by a beater so that the long fiber content is reduced as much as possible. For example, it is preferable to beat the pulp so that the weighted average fiber length of the pulp after the beating is 0.4 to 0.75 mm. Then, a base paper is preferably formed by using a fourdrinier paper machine by using an appropriate papermaking method for the stock slurry to which the internal additive has been added so that a uniform formation can be obtained.
Specifically, for example, to give a suitable turbulence to the stock slurry, using a fourdrinier paper machine having a suitable upper dewatering mechanism as described or exemplified in JP-A-61-284762, As the press, a multi-stage wet press, preferably a three-stage or more wet press is performed, and a smooth paper roll is provided at the final stage of the press part, so that a uniform formation can be obtained by combining appropriate papermaking methods. Machine, and after the machine, machine calendar,
A calendering treatment is performed using a super calender, a heat calender, or the like, and a base paper having a film thickness unevenness index Rpy of 250 mV or less can be manufactured.

As the base paper mainly composed of natural pulp used in the practice of the present invention, a stylus type three-dimensional surface roughness meter on the front side of the base paper is used from the viewpoint of further improving the glossiness of the photographic material. Center surface average roughness SRa in the papermaking direction at a cutoff value of 0.8 mm measured by the following method (hereinafter, a cutoff value of 0.8 mm measured using a stylus type three-dimensional surface roughness meter on the front side of the base paper)
The term "center plane average roughness SRa in the papermaking direction in the above-mentioned method is sometimes simply abbreviated as center plane average roughness SRa).
m or less is useful, preferably 1.40 μm or less, more preferably 1.35 μm or less.
Those having a size of 25 μm or less are particularly preferred. The center plane average roughness SRa at a cut-off value of 0.8 mm measured using a stylus type three-dimensional surface roughness meter referred to in the present specification is defined by Formula 1.

[0066]

(Equation 1)

In Equation 1, Wx represents the length of the sample surface area in the X-axis direction (papermaking direction), Wy represents the length of the sample surface area in the Y-axis direction (direction perpendicular to the papermaking direction), and Sa Represents the area of the sample surface area.

As a method for producing a base paper having a center plane average roughness SRa of 1.45 μm or less, which is preferably used in the practice of the present invention, concretely, sulfite pulp, which is easy to produce smoothness, preferably hardwood Sulfite pulp is used in an amount of 30% by weight or more, preferably 50% by weight or more, and a multi-stage press is performed during the drying of the wet paper. 2 or more calendar processes,
For example, machine calendering and / or thermal machine calendering are performed on the base paper as the first series of calendering, and then machine calendering is further performed as necessary for the second and subsequent calenders.
A base paper having a center plane average roughness SRa of 1.45 μm or less can be manufactured by performing a thermal soft calender treatment described or exemplified in Japanese Patent Publication No. 110939. In addition, various water-soluble polymers or hydrophilic colloids or polymer latexes are coated on a base paper or on a base paper by a size press, a tab size press, a blade coating, an air knife coating or the like to give a solid coating amount of 1.0 g / g. m ²
As described above, it is particularly preferable to contain or apply 2.2 g / m ² or more.

The surface of the surface resin layer of the support for photographic materials in the present invention is subjected to activation treatment such as corona discharge treatment and flame treatment.
An undercoat layer as described or exemplified in Japanese Patent Application Laid-Open No. Hei. Further, on the back resin layer surface of the photographic material support of the present invention, after performing an activation treatment such as a corona discharge treatment or a flame treatment, various back coat layers are coated for antistatic and the like. Can be. Further, the back coat layer, JP-B-52-18020, JP-B-57-9059, JP-B-57-53940, JP-B-58-56859, JP-A-5
No. 9-214849, Japanese Patent Application Laid-Open No. 58-184144 and the like or inorganic antistatic agents, organic antistatic agents, hydrophilic binders, latexes, curing agents, pigments, surfactants and the like are appropriately combined and contained. I can do it.

The support for a photographic material in the present invention is coated with various photographic image forming layers and is used for color photographic printing paper, black and white photographic printing paper, typesetting printing paper, copy photographic paper, and reversing photographic material. It can be used for various uses such as silver salt diffusion transfer method for negative and positive, and for printing materials. For example, a silver chloride, silver bromide, silver chlorobromide, silver iodobromide, silver chloroiodobromide emulsion layer can be provided. The silver halide photographic emulsion layer may contain a color coupler to provide a multilayer silver halide color photographic image forming layer. Further, a photographic image forming layer for silver salt diffusion transfer method can be provided. As a binder for these photographic image forming layers, hydrophilic polymers such as polyvinylpyrrolidone, polyvinyl alcohol and polysaccharide sulfate ester compounds can be used in addition to ordinary gelatin. Further, the photographic image forming layer may contain various additives. For example, as a sensitizing dye, a cyanine dye, a merocyanine dye, etc., as a chemical sensitizer, a water-soluble gold compound, a sulfur compound,
As antifoggants or stabilizers, hydroxy-triazolopyrimidine compounds, mercapto-heterocyclic compounds, etc .; as hardeners, formalin, vinylsulfone compounds, aziridine compounds, etc .; as coating aids, alkylbenzenesulfonates, sulfosuccinates Dialkyl hydroquinone compounds, etc., as well as fluorescent brighteners, sharpness improving dyes, antistatic agents, pH adjusters, fogging agents, and water-soluble iridium, water-soluble during the production and dispersion of silver halide A suitable rhodium compound or the like can be contained in combination.

The photographic material according to the present invention is subjected to exposure, development, and stoppage according to the photographic material, as described in "Photosensitive Material and Handling Method" (Kyoritsu Shuppan, Goro Miyamoto, Photographic Technology Course 2). , Fixing, bleaching, and stabilization. Further, the multi-layer silver halide color photographic material may be treated with a developer containing a development accelerator such as benzyl alcohol, thallium salt, phenidone or the like, or may be treated with a developer substantially free of benzyl alcohol. it can.

[0072]

EXAMPLES Next, examples will be described in order to more specifically explain the present invention.

Examples 1 to 9 and Comparative Examples 1 to 3 During the production of anatase type titanium dioxide by the sulfuric acid method, a hydroxide prepared by previously neutralizing the titanyl sulfate solution separately was added as a seed to the titanyl sulfate solution. Thereafter, the temperature was raised and brought to a boil, and hydrolysis was carried out to produce titanium dioxide.
Thereafter, the powder was washed by filtration, and anatase-type titanium dioxide clinker produced under a predetermined firing condition so as to have a particle diameter shown in Table 1 was dry-pulverized with a centrifugal roller mill, and the pulverized product was dried in the presence of sodium hydroxide. Suspended in water to form a titanium dioxide slurry, further wet-milled in a wet ball mill, and wet-classified using a continuous horizontal centrifuge to obtain approximately 25% by weight substantially free of coarse titanium dioxide.
50% by weight of an amount of 0.15%, 0.50% or 2.0% by weight calculated in the form of Al ₂ O ₃ with respect to titanium dioxide on a dry basis. Was added and kept for 30 minutes. Next, the pH of the slurry was lowered to 7.0 by adding 20% by weight sulfuric acid, and the slurry was aged for 2 hours. After aging, the first mother liquor of the titanium dioxide slurry surface-treated with hydrous aluminum oxide was filtered with a filter press, and then the titanium dioxide cake in the filter press was run with running water, and a suspension of 50 μmho (μΩ ⁻¹ ) / cm was obtained. Washing was performed under predetermined washing conditions until a titanium dioxide pigment having electrical conductivity was obtained.

Thereafter, the titanium dioxide cake was taken out, water was added, and the titanium dioxide concentration was adjusted to 5 with an industrial mixer.
The slurry was prepared into an aqueous slurry of 00 g / l and then sprayed at a hot air inlet temperature of about 150 ° C (EYELA, SD
-1) and further pulverized through a superheated steam at about 250 ° C. using a steam mill equipped with a quantitative feeder to produce a titanium dioxide pigment used in the present invention.

Separately, the above-mentioned titanium dioxide cake was dried in a rotary drying furnace, and subsequently pulverized through a superheated steam at about 250 ° C. using a steam mill with a fixed-quantity feeder to obtain a titanium dioxide pigment for comparison in a different drying method. Manufactured.

For each of the titanium dioxide pigments thus obtained, a low-density polyethylene resin (density of
923 g / cm ³ , MFR = 8.5 g / 10 min) 47.5% by weight,
50% by weight of titanium dioxide pigment and 2.5% by weight of zinc stearate, 240 ppm of 1, as an antioxidant,
3,5-tris (4-tert-butyl-3-hydroxy-
In the presence of (2,6-dimethyl-benzyl) cyanurate, using a Banbury mixer, the mixture was well kneaded at 150 ° C., cooled, and pelletized to obtain master batches of titanium dioxide pigments.

On the other hand, the fiber length of the pulp after beating a mixed pulp composed of 30% by weight of hardwood bleached kraft pulp and 70% by weight of hardwood bleached sulphite pulp (JAPAN)
TAPPI paper and pulp test method No. 52-89 (expressed as a length-weighted average fiber length measured in accordance with "Paper and pulp fiber length test method") was beaten to 0.58 mm, and then 100 weight of pulp was obtained. Parts by weight, 3 parts by weight of cationized starch, 0.2 parts by weight of anionized polyacrylamide, 0.4 parts by weight of alkyl ketene dimer emulsion (as ketene dimer), 0.4 parts by weight of polyamide epichlorohydrin resin and an appropriate amount , A blue dye and a red dye were added to prepare a stock slurry. Thereafter, the stock slurry is placed on a fourdrinier machine running at 200 m / min, and a paper web is formed while giving an appropriate turbulence, and a linear pressure of 15 kg / cm to 100 kg / cm is applied in the wet part. After performing the adjusted three-stage wet press, treated with a smoothing roll, and subsequently 30 kg / cm in the drying part
After performing a two-stage tension press in which the linear pressure was adjusted in the range of ７０70 kg / cm, it was dried. Thereafter, during the drying, 25 g / size press solution composed of 4 parts by weight of carboxy-modified polyvinyl alcohol, 0.05 parts by weight of a fluorescent whitening agent, 0.002 parts by weight of a blue dye, 4 parts by weight of sodium chloride and 92 parts by weight of water. m ² size was pressed, the finally obtained base paper moisture is dried to be 8 wt% in absolute dry moisture, linear pressure 70kg
/ cm machine calendering, the film thickness unevenness index Rpy with a basis weight of 170 g / m ² is 130 mV, and the center plane average roughness SR
A base paper having a of 1.20 μm was produced.

Next, after the base paper surface (back surface) opposite to the side on which the photographic image forming layer is provided is subjected to corona discharge treatment, a low-density polyethylene resin (density 0.924 g / cm ³ , MFR
= 1 g / 10 min), and 30 parts by weight of a high-density polyethylene resin (density 0.967 g / cm ³ , MFR = 15 g / 10 min) in a weight of 25% at a resin temperature of 320 ° C.
The resin was melt-extruded and coated at a resin thickness of μm at a running speed of the base paper of 200 m / min. At this time, as a cooling roll,
The surface of the back resin layer having a center line average roughness Ra defined by JIS K0601 having a roughness of 1.0 μm was used. The cooling roll used was a cooling roll roughened by a liquid honing method and operated at a cooling water temperature of 12 ° C.

Subsequently, the base paper surface (surface) on the side on which the photographic image forming layer is provided was subjected to corona discharge treatment, and then 30 parts by weight of the above-mentioned titanium dioxide pigment masterbatch and a high-density polyethylene resin (density 0.967 g / cm ³ , MFR =
6.8 g / 10 min) and 50 parts by weight of a low-density polyethylene resin (density 0.924 g / cm ³ , MFR = 3.0 g / 10 min) were mixed at a resin temperature of 315 ° C.
It was melt-extruded and coated to a thickness of 0 μm at a running speed of the base paper of 200 m / min and an effective press pressure of a cooling roll and a press roll of 30 kg / cm ² using a melt extrusion coating machine.
At this time, as the cooling roll, a chrome-plated fine rough surface was used, and operation was performed at a cooling water temperature of 12 ° C. Further, the melt extrusion coating of the front and back resin compositions was performed by a so-called tandem method in which extrusion coating was performed sequentially.

Subsequently, before the front and back resins were processed and wound up, the backside resin layer surface of the resin-coated paper was subjected to a corona discharge treatment, and the following backcoat coating solution was applied on-machine.
Gelatin: silicon dioxide matting agent (average particle size: 2 μm) = 3: 1 as dry weight, containing 15% by weight of gelatin relative to epoxy hardener, appropriate amounts of coating aid and inorganic antistatic agent Backcoat coating solution is gelatin content 2
Coating was performed at a coating amount of g / m ² minutes to obtain a support for photographic material.

The method of evaluating the releasability of the surface resin layer from the cooling roll when producing each photographic material support is as follows.
The peeling angle θ shown in FIG. 1 was measured, and the grade of the grade was evaluated in ten steps in consideration of the overall irregularity of the peeling.
The evaluation criteria (the larger the numerical value of the grade, the better the releasability, and the smaller the numerical value of the grade, the worse the releasability, indicating that the film is in an irregular peeled state).
9: peeling angle θ is less than 3 °, very good peelability, grade 8 to 7; peeling angle θ of less than 5 °, good peelability, grade 5 to 6; peeling angle θ of less than 8 °, peeling It shows slight irregularity but no problem in actual operation, grade 4 ~
1: When the peeling angle θ is 8 ° or more, irregularity of peeling is exhibited, and the degree of peeling in actual operation is a problem.

A photographic material is produced by coating a black-and-white silver halide photographic image-forming layer as an image-forming layer on the support for photographic material to produce a photographic material. Evaluation was performed by the method described.

After coating the backcoat coating solution and before winding the resin-coated paper, the resin surface on the front side of the support was subjected to corona discharge treatment to give 0.75 g of lime-treated gelatin and low molecular weight gelatin (Nitta Gelatin Co., Ltd. P-3226)
0.75 g, 0.3 g of a 10% by weight methanol solution of butyl parahydroxybenzoate and 0.45 g of a 5% by weight mixture of methanol and water of 2-ethylhexyl sulfosuccinate were adjusted to 100 g with water. The blended undercoating solution was uniformly applied on-machine so as to have a gelatin coating amount of 0.06 g / m ² to obtain a support for photographic materials.

Next, an emulsion layer and a protective layer thereof were provided as a black-and-white silver halide photographic image forming layer on the undercoat layer on the front side of the support for photographic materials to obtain a black-and-white photographic printing paper. The emulsion layer is 2.4 × 10 ⁻⁶ g of potassium hexachlororhodate (III).
Produced by dispersing 19.2 g of silver halide grains with silver nitrate in 8.6 g of gelatin in the presence of ArBr /
AgCl / AgI = 50.6 / 49.0 / 0.4 (mol%) Halogen composition Sulfur sensitization to optimum sensitivity with an average particle size of 0.6 μm substantially consisting of [1,0,0] plane Including a neutral method silver halide photographic emulsion, in addition to gelatin necessary for film formation, also includes an appropriate amount of a stabilizer, a sensitizing dye, a coating aid, a hardening agent, a fluorescent brightener, a thickener, 2.3g / with silver nitrate
Coating was carried out with the protective layer at a coating weight corresponding to 4.5 g / m ² with m ² and gelatin. The protective layer contains a coating aid and a hardener in addition to gelatin corresponding to ² g / m ² .

Regarding the evaluation of the sharpness of the printed image,
After the coated and dried sample is stored for 1 day at 35 ° C and normal humidity,
A test chart was obtained by closely attaching a resolving power chart to the sample, exposing it with white light, and performing black and white development processing. This test sheet was measured with a microdensitometer, calculated by a personal computer according to a conventional method, and determined as MT of image sharpness.
F (Modulation Transfer Function) was determined, and the sharpness of the printed image of the photographic material support was determined. The larger the value of MTF, the higher the sharpness of the printed image.

Regarding the evaluation of the storability of the photographic material, the coated and dried sample was kept at 35 ° C. for one day under normal humidity and at 55 ° C.
For 4 days, exposed to sensitometry, stopped after black and white development, fixed, washed with water, and dried to measure photographic properties and to evaluate the storability.

The evaluation criteria for the storability of photographic materials include:
5: Change in sensitivity and generation of fog are considerably small, and storage stability is fairly good. 4: Change in sensitivity and generation of fog are small and storage stability is good. 3: There is a slight change in sensitivity and fogging, but to some extent practicable 2: To some extent, there is a change in sensitivity and fogging, and storage is sometimes a problem; 1: The change in sensitivity and fogging is quite large; It indicates the degree to which the storage stability cannot be practically used.

Table 1 shows the obtained results.

[0089]

[Table 1]

Note that (Note 1) to (Note 4) in Table 1 are as follows.

(Note 1) Calculated in the form of Al ₂ O ₃ and represents weight% based on titanium dioxide.

(Note 2) It is indicated by the number average diameter described in the text of the specification.

(Note 3) Spray method: Indicates a method of spray drying. Rotary drying method: represents a method of drying in a rotary drying furnace.

(Note 4) MTF is indicated by a value at 7 lines / mm.

As apparent from Table 1, the titanium dioxide pigment contained in the surface resin layer of the support for the resin-coated paper type photographic material was produced by spray drying and had an apparent density of 0.1. The support for photographic material of the present invention (Examples 1 to 9) using a titanium dioxide pigment of 32 g / cm ³ or more has high sharpness of a printed image, good storage stability of the photographic material, and It can be clearly seen that this is an excellent support having good releasability of the surface resin layer from the cooling roll. Also, as the titanium dioxide pigment,
From the viewpoint of improving the sharpness of the printed image, the storability of the photographic material, and the releasability of the surface resin layer from the cooling roll, those having an apparent density of 0.35 g / cm ³ or more are preferable, and the effects of the present invention are obtained. In particular, from the viewpoint of the effect of improving the sharpness of the printed image, it is well understood that the number average diameter is preferably in the range of 0.110 μm to 0.150 μm, and more preferably in the range of 0.115 μm to 0.135 μm. . From the viewpoint of the effect of the present invention, the surface of the titanium dioxide pigment contains at least aluminum atoms in an amount of 0.25% by weight to 1.5% by weight calculated on the surface of titanium dioxide in the form of anhydrous metal oxide. It is understood that those treated with the hydrated metal oxide are preferable.

On the other hand, as the titanium dioxide pigment, a pigment dried by a rotary drying method was used (Comparative Example 2), or a pigment having an apparent density of less than 0.32 g / cm ³ was used (Comparative Examples 1 and 2). It can be seen that the support for photographic materials other than the present invention in Comparative Example 3) had problems because the sharpness of the printed image was low, the preservability was poor, and the releasability of the surface resin layer from the cooling roll was poor. .

Examples 10 to 20 and Comparative Example 4 In Examples 1 to 9 and Comparative Examples 1 and 3, a 2% by weight aqueous solution of methyltrimethoxysilane was added to the aqueous slurry before spray drying. Titanium dioxide pigments were produced in the same manner as in Examples 1 to 9 and Comparative Examples 1 and 3, except that 1.0% by weight (as an organic substance) was added, mixed well, and then spray-dried. Comparative Example 2 was repeated except that a 2% by weight aqueous solution of methyltrimethoxysilane was added to the aqueous slurry before filtration with a filter press in an amount of 1.0% by weight (as an organic substance) based on titanium dioxide. In the same manner as in the above, a titanium dioxide pigment was produced. The procedure was performed in the same manner as in Example 1 except that these titanium dioxide pigments were used instead of the titanium dioxide pigment used in Example 1.

Table 2 shows the obtained results.

[0099]

[Table 2]

Incidentally, (Note 1) to (Note 4) in Table 2 have the same meanings as those in Table 1.

As is clear from Table 2, the titanium dioxide pigment to be contained in the surface resin layer of the support for the resin-coated paper type photographic material was an organic surface-treated pigment which was produced by spray drying. , And the apparent density is 0.
The support for photographic materials of the present invention (Examples 10 to 26) using a titanium dioxide pigment of 32 g / cm ³ or more has high sharpness of a printed image, good storage stability of the photographic material, and It can be clearly seen that this is an excellent support having good releasability of the surface resin layer from the cooling roll.
The titanium dioxide pigment has an apparent density of 0.35 g / cm ^{3 in} terms of the sharpness of the printed image, the storability of the photographic material, and the effect of improving the releasability of the surface resin layer from the cooling roll.
It is well understood that the above is preferable, and the one having an apparent density of 0.38 g / cm ³ or more is particularly preferable. Further, from the viewpoint of the effects of the present invention, particularly from the viewpoint of the effect of improving the sharpness of a printed image, those having a number average diameter in the range of 0.110 μm to 0.150 μm are preferable, and those having a number average diameter in the range of 0.115 μm to 0.135 μm. It can be seen that those are more preferable. Further, as the titanium dioxide pigment, from the viewpoint of the effect of the present invention, the surface thereof contains at least aluminum atom in an amount of 0.25% by weight to 1.5% by weight calculated in the form of anhydrous metal oxide per titanium dioxide. It is understood that those treated with the hydrated metal oxide are preferable. Further, from a comparison between Tables 1 and 2, it is clear that the titanium dioxide pigment used in the present invention preferably has been subjected to an organic surface treatment.

On the other hand, when a titanium dioxide pigment having an apparent density of less than 0.32 g / cm ³ dried by a rotary drying method was used (Comparative Example 4), the support for a photographic material outside the present invention was: , Low sharpness of print image, poor preservation,
Further, it can be seen that the releasability of the surface resin layer from the cooling roll is poor and there is a problem.

Examples 21 to 27 and Comparative Examples 5 to 8 When producing anatase type titanium dioxide by the sulfuric acid method, an aqueous solution of titanyl sulfate was added to warm water to seed (internal seed).
Was generated, and the mixture was heated and boiled for hydrolysis to produce titanium dioxide. Thereafter, described in Example 5, except that the calcination conditions predetermined to obtain the particle diameters of titanium dioxide described in Table 3 were used, and the surface treatment was performed with the amount of hydrous aluminum hydroxide shown in Table 3. The titanium dioxide pigment of the internal seed method was produced through the same procedure as the external seed method. In addition, it is necessary to use firing conditions determined in advance so as to obtain the particle diameters of titanium dioxide described in Table 3.
In the same manner as in Example 5 except that the surface treatment was performed using the amount of hydrous aluminum hydroxide described in Example 5, a titanium dioxide pigment was produced by an external seed method. For comparison, a titanium dioxide pigment of a rotary drying method was produced in the same manner as in Comparative Example 2. The organic surface-treated titanium dioxide pigment was produced by treating the organic surface with 1.0% by weight of methyltrimethoxysilane per titanium dioxide in the same manner as in Example 16. These titanium dioxide pigments were used in Example 5
Example 5 was carried out in the same manner as in Example 5 except that the titanium dioxide pigment used in Example 1 was used instead.

Table 3 shows the obtained results.

[0105]

[Table 3]

Note that (Note 1) to (Note 4) in Table 3 have the same meanings as those in Table 1.

As is apparent from Table 3, the titanium dioxide pigment contained in the surface resin layer of the support for the resin-coated paper type photographic material was produced by spray drying and had an apparent density of 0.1. The support for a photographic material of the present invention (Examples 21 to 27) using a titanium dioxide pigment of 32 g / cm ³ or more has high sharpness of a printed image, good storage stability of the photographic material, and It can be clearly seen that this is an excellent support having good releasability of the surface resin layer from the cooling roll. As the titanium dioxide pigment, those having an apparent density of 0.35 g / cm ³ or more from the viewpoint of improving the sharpness of the printed image, the storability of the photographic material, and the effect of improving the releasability of the surface resin layer from the cooling roll. It is well understood that those having an apparent density of 0.38 g / cm ³ or more are particularly preferable. It is also clear that the titanium seed pigment used in the present invention is more preferably an external seed method from the viewpoint of the overall improvement effect of the present invention. Further, as the titanium dioxide pigment, from the viewpoint of the effect of the present invention, the surface thereof contains at least aluminum atom in an amount of 0.25% by weight to 1.5% by weight calculated in the form of anhydrous metal oxide per titanium dioxide. It is understood that those treated with the hydrated metal oxide are preferable. Further, it can be clearly seen that the titanium dioxide pigment used in the present invention is preferably an organic surface-treated pigment.

On the other hand, when a titanium dioxide pigment dried by a rotary drying method was used (Comparative Example 8), or a titanium dioxide pigment having an apparent density of less than 0.32 g / cm ³ was used (Comparative Examples 5 to 5). It can be seen that the support for photographic material 7) other than the present invention has a problem in that the sharpness of the printed image is low, the preservability is poor, and the releasability of the surface resin layer from the cooling roll is poor.

Examples 28 to 38 and Comparative Examples 9 to 10 In Example 1, the titanium dioxide pigment was calculated in the form of Al ₂ O ₃ with respect to titanium dioxide on a dry basis to give the weight% shown in Table 4. 50% by weight of the amount of sodium aluminate
Titanium dioxide pigment surface-treated with hydrous aluminum hydroxide, prepared in the same manner as in Example 1 except that an aqueous solution is added,
After adding a 10% by weight aqueous solution of sodium silicate to the amount shown in Table 4 by weight in the form of ₂ in Table ₂ , it was calculated in the form of Al ₂ O ₃ with respect to titanium dioxide on a dry basis. A titanium oxide surface-treated with hydrous silicon oxide or hydrous silicon oxide and hydrous aluminum oxide, prepared in the same manner as in Example 1 except that a 50% by weight aqueous solution of sodium aluminate is added in the amount described in the above section. Before raising the pH of the pigment or the titanium dioxide slurry with sodium hydroxide, the pH was calculated in the form of TiO ₂ against the titanium dioxide on a dry basis.
Of a 5% by weight aqueous solution of titanyl sulfate described in Table 4 and a 50% by weight aqueous solution of sodium aluminate in an amount of a weight% described in Table 4 with respect to titanium dioxide on a dry basis. The procedure was carried out in the same manner as in Example 1 except that a masterbatch of a titanium dioxide pigment surface-treated with hydrous aluminum hydroxide and titanium oxide was used, except that a masterbatch was used. In addition, the number average diameter of titanium dioxide was in the range of 0.122 μm to 0.127 μm.

Table 4 shows the obtained results.

[0111]

[Table 4]

[0112] (Note 4) to (Note 5) in Table 4 are as follows.

(Note 4) It is the same as that in Table 1.

[0114] (Note 5) hydrated aluminum oxide surface of the titanium dioxide, the processing amount of the surface-treated surface treating agent in water, silicon dioxide or / and water titanium dioxide, respectively of titanium dioxide dry basis Al ₂ O ₃ , SiO ₂ ,
It is expressed as a percentage by weight when calculated in the form of TiO ₂ .

As apparent from Table 4, the titanium dioxide pigment contained in the surface resin layer of the resin-coated paper type photographic material support was produced by spray drying and had an apparent density of 0.1. The support for a photographic material of the present invention (Examples 28 to 38) using a titanium dioxide pigment of 32 g / cm ³ or more has high sharpness of a printed image, good storage stability of the photographic material, and It can be clearly seen that this is an excellent support having good releasability of the surface resin layer from the cooling roll. As the titanium dioxide pigment, those having an apparent density of 0.35 g / cm ³ or more from the viewpoint of improving the sharpness of the printed image, the storability of the photographic material, and the effect of improving the releasability of the surface resin layer from the cooling roll. It is clear that it is preferable. As the titanium dioxide pigment, from the viewpoint of the effect of the present invention, the surface thereof is preferably calculated as 0.25% by weight to 1.25% by weight in terms of anhydrous metal oxide per titanium dioxide.
It can be clearly seen that it has been treated with 5% by weight, particularly preferably 0.35% to 1.25% by weight, of a hydrated metal oxide containing at least aluminum atoms.

On the other hand, when a titanium dioxide pigment having an apparent density of less than 0.32 g / cm ³ was used (Comparative Examples 9 to 10).
It can be seen that the support for photographic material out of the present invention 10) has a problem in that the sharpness of the printed image is low, the storage stability is poor, and the releasability of the surface resin layer from the cooling roll is poor.

Examples 39 to 42 and Comparative Examples 11 to 12 In Examples 24 to 27 and Comparative Examples 7 to 8, the following multilayer silver halide color photographic image forming layer was used in place of the black and white silver halide photographic image forming layer. Was carried out in the same manner as in Examples 24 to 27 and Comparative Examples 7 to 8 except that color development, bleach-fixing, and washing were performed after decomposition exposure instead of black and white development.

The multilayer silver halide color photographic image forming layer is composed of a blue-sensitive silver halide emulsion layer, an intermediate layer, a green-sensitive silver halide emulsion layer, and an ultraviolet absorber adjacent to the undercoat layer of the support for image materials. The layers, the red-sensitive silver halide emulsion layer and the protective layer were located at the same time, and six layers were simultaneously coated from the multilayer coating E bar.

The blue-sensitive silver halide photographic emulsion layer has a halogen composition of AgBr / AgCl = 95/5 produced by the first thermoforming in the presence of an appropriate amount of potassium hexachloroiridate (III). A neutral silver halide emulsion composed of a mixed crystal of [1, 0, 0] and [1, 1, 1] planes sensitized with sulfur to an optimum sensitivity of 0.8 μm was added at a silver nitrate content of 0.8.
Comprising 6 g / m ^2, yet another gelatin 1.5 g / m ² and yellow color couplers, including a suitable amount of stabilizers, blue sensitized for sensitizing dyes, coating aids, hardening agents, thickeners, and the like. The intermediate layer is gelatin 1.
In addition to 5g / m ² , an appropriate amount of anti-color mixing agent, coating aid, thickener,
Includes hardener.

The green-sensitive silver halide emulsion layer is formed by a first heat-forming method in the presence of an appropriate amount of potassium hexachlororhodate (III) and potassium hexachloroiridium (III), and a halogen of AgBr / AgCl = 95/5. An acid-processed silver halide emulsion consisting essentially of [1,0,0] plane sulfur-sensitized to an optimum sensitivity having an average grain size of 0.4 μm and having a silver nitrate content of 0.6 g / m ² ; 1.
5 g / m ² and magenta color coupler, as well as an appropriate amount of stabilizer,
Sensitizing dye for greenness, sharpness improving dye, coating aid, hardener,
Including thickeners. The UV-absorbing layer contains 1.5 g / m ² of gelatin and an appropriate amount of UV absorber, coating aid, thickener, hardener and the like.

The red-sensitive silver halide emulsion layer contains a silver halide emulsion produced in exactly the same manner as the green-sensitive silver halide emulsion at a silver nitrate content of 0.6 g / m ² , and further has a gelatin of 1.5 g / m ^2. And an appropriate amount of a stabilizer, a red sensitizing dye, a sharpness improving dye, a coating aid, a hardener, a thickener and the like in addition to a cyan coloring coupler. The protective layer contains an appropriate amount of a coating aid, a thickener, a hardener and the like in addition to 1.5 g / m ² of gelatin.

As a method for evaluating the sharpness of a printed image, a test sheet was obtained by closely attaching a resolving power chart to the obtained color printing paper, exposing it to green light, and performing color development processing. This test sheet was measured with a microdensitometer, calculated with a personal computer according to a conventional method, and determined as MTF (Modula
The transfer function (modulation transfer function) was determined, and the sharpness of the printed image of the photographic material support was determined.

Table 5 shows the obtained results.

[0124]

[Table 5]

Note that (Note 6) in Table 5 is as follows.

(Note 6) MTF is indicated by a value of 5 lines / mm.

As is clear from Tables 5 and 3, when a multilayer silver halide color photographic image forming layer was used (Example 39)
To 42 and Comparative Examples 11 to 12) obtained completely the same results as those when the black and white silver halide photographic image forming layer was used (Examples 24 to 27 and Comparative Examples 7 to 8). In particular, it is well understood that the support for photographic materials in the present invention has a high sharpness of a printed image.

Examples 43 to 52 The same procedures as in Example 16 were carried out except that a 2% by weight aqueous solution of methyltrimethoxysilane was added in the amount shown in Table 6 per titanium dioxide.

Table 6 shows the obtained results.

[0130]

[Table 6]

Note that (Note 4) and (Note 7) to
(Note 8) is as follows.

(Note 4) It is the same as that in Table 1.

(Note 7) The treatment amount of the organic surface treating agent with respect to the titanium dioxide on a dry basis is indicated in terms of% by weight (as an organic substance).

(Note 8) As an evaluation method with an emulsion film,
After the development, the emulsion surface was scratched vertically and horizontally at intervals of 1 cm with a nail to make a grid-like scratch, and then the surface was rubbed with a fingertip in running water to evaluate the degree of peeling of the emulsion layer. The evaluation criteria are as follows. ：: No peeling of emulsion layer, good film formation. ：: little peeling of emulsion layer, but no problem in practical use. Δ: Emulsion of the emulsion layer was slightly large, but practical. C: Many peelings of the emulsion layer, and there is a practical problem with film formation.

As is clear from Table 6, the titanium dioxide pigment contained in the surface resin layer of the support for the resin-coated paper type photographic material was produced by spray drying and had an apparent density of 0.1. The supports for photographic materials in the present invention (Examples 43 to 52) using a titanium dioxide pigment of 32 g / cm ³ or more have high sharpness of printed images, good storability of photographic materials, and It can be clearly seen that this is an excellent support having good releasability of the surface resin layer from the cooling roll. As the titanium dioxide pigment, from the viewpoint of improving the sharpness of a printed image, the preservability of a photographic material, the effect of improving the releasability of a surface resin layer from a cooling roll, and the performance with an emulsion film, the surface treatment amount with an organic substance is preferred. Is 0.05
It is well understood that the content is preferably in the range of 0.5% to 4.0% by weight, and particularly preferably 0.5% to 2.0% by weight.

Examples 53 to 54 In Example 16, N-β-aminoethyl-γ-aminopropyldimethoxysilane (Example 53) or ε was used instead of a 2% by weight aqueous solution of methyltrimethoxysilane.
A 2% by weight aqueous solution of caprolactam (Example 54) at 1.0% by weight per titanium dioxide (as organic matter)
Except for the addition, the same procedure as in Example 16 was carried out to give excellent sharpness of the printed image, good preservability of the photographic material, and good releasability of the surface resin from the cooling roll. Supports for photographic materials (Examples 53 to 54) were obtained. The apparent density of the titanium dioxide pigment of Example 53 was 0.40 g / cm ³ , and the apparent density of the titanium dioxide pigment of Example 54 was 0.39 g / cm ³ .

Examples 55 to 67 In Examples 28 to 38 and Comparative Examples 9 to 10, a 2% by weight aqueous solution of methyltrimethoxysilane was added to an aqueous slurry before spray drying at 1.0% by weight per titanium dioxide.
Examples 28 to 38 and Comparative Examples 9 to 10 except that they were added (as organic materials), mixed well, and then spray-dried.
In the same manner as in the above, titanium dioxide pigments shown in Table 7 were produced. The procedure was performed in the same manner as in Example 1 except that these titanium dioxide pigments were used instead of the titanium dioxide pigment used in Example 1. The number average diameter of the titanium dioxide pigment is
The range was from 0.122 μm to 0.127 μm.

Table 7 shows the obtained results.

[0139]

[Table 7]

Note that (Note 4) to (Note 5) in Table 7 have the same meanings as those in Table 4.

As is clear from Table 7, the titanium dioxide pigment contained in the surface resin layer of the support for the resin-coated paper type photographic material was produced by spray drying and had an apparent density of 0.1. The support for a photographic material of the present invention using a titanium dioxide pigment of 32 g / cm ³ or more (Examples 55 to 67) has high sharpness of a printed image, good storage stability of the photographic material, and It can be clearly seen that this is an excellent support having good releasability of the surface resin layer from the cooling roll. As the titanium dioxide pigment, those having an apparent density of 0.35 g / cm ³ or more from the viewpoint of improving the sharpness of the printed image, the storability of the photographic material, and the effect of improving the releasability of the surface resin layer from the cooling roll. Preferably 0.3
It can be clearly seen that those with 8 g / cm ³ or more are particularly preferable.
In addition, from the viewpoint of the effect of the present invention, the surface of the titanium dioxide pigment is preferably calculated as 0.25% by weight to 1.5% by weight in terms of the amount of anhydrous metal oxide per titanium dioxide.
Particularly preferably from 0.35% to 1.25% by weight,
It can be clearly seen that the substrate was treated with a hydrated metal oxide containing at least an aluminum atom.

From the comparison between Table 4 and Table 7, the titanium dioxide pigment used in the present invention is preferably an organic surface-treated pigment. Particularly, the effect of the present invention is that the surface of the titanium dioxide pigment is Calculated in anhydrous metal oxide form per titanium dioxide, preferably 0.25% by weight to 1.25% by weight.
By using 5% by weight, particularly preferably 0.35% to 1.25% by weight of a hydrated metal oxide containing at least aluminum atoms, and using an organic surface treatment, It can be clearly seen that it is remarkable.

Examples 68 to 69 Instead of the size press liquid used in Example 1, an aqueous dispersion of a high-molecular polyester resin (Toyo Co., Ltd.) was used in such an amount that the coating amount on one side was 2 g / m ² (as dry weight). Spinning Co., Ltd., trade name: Vironal MD-1930) Optical brightener 0.05
% By weight, 0.002% by weight of blue dye, 0.5% by weight of metal polystyrene sulfonate-based antistatic agent and the remaining weight%
In the same manner as in Example 1 using a size press liquid composed of water of
^Two base papers were produced. Then, after the back surface of the base paper was subjected to corona discharge treatment, a thermoplastic polyester resin (manufactured by Eastman Chemical Japan Co., Ltd., trade name: Kodapack-PET 298LB) was 25 μm at a resin temperature of 270 ° C.
The resin was subjected to melt extrusion coating in the same manner as in Example 1 at a running speed of the base paper of 150 m / min. Subsequently, after subjecting the surface of the base paper to corona discharge treatment, a resin composition comprising 35 parts by weight of a titanium dioxide pigment master batch described below and 65 parts by weight of the polyester-based resin was heated to a resin temperature of 270 ° C.
With a running speed of 150 m / min of the base paper to a resin thickness of 30 μm,
Melt extrusion coating was performed in the same manner as in Example 1, and thereafter, the same as in Example 1 or Example 11,
An excellent photographic material support having high sharpness of a printed image and good storability of the photographic material (Examples 68 to 6)
9) was obtained.

As a titanium dioxide pigment master batch,
67.5% by weight of the polyester resin, 30% by weight of the titanium dioxide pigment used in Example 1 or Example 11, and 2.5% by weight of zinc stearate were added to an appropriate amount of 1,3,5-tris (4-tert. In the presence of -butyl-3-hydroxy-2,6-dimethyl-benzyl) cyanurate, a titanium dioxide pigment masterbatch produced by kneading well using a twin-screw kneading extruder, cooling and pelletizing was used.

[0145]

According to the present invention, the sharpness of a printed image is high, the storage stability with respect to a silver halide photosensitive layer is remarkably improved, and the releasability from a cooling roll during the production of a support is remarkably improved. Thus, there can be provided a support for a resin-coated paper type photographic material capable of providing a photographic material excellent in glossiness without occurrence of peeling unevenness.

[Brief description of the drawings]

FIG. 1 is a definition diagram of a peel angle θ.

[Brief description of reference numerals]

 DESCRIPTION OF SYMBOLS 1 Cooling roll (cooling roll) 2 Press roll 3 Peeling roll 4 Surface resin layer composition 5 Base (base paper having a back resin layer) 6 Die 7 Peeling angle θ

Claims (8)

(57) [Claims] 1. A photographic material support comprising a paper mainly composed of natural pulp as a substrate and one of the paper substrate surfaces on which a photographic image forming layer is provided, coated with a thermoplastic resin (A) layer. The thermoplastic resin (A) layer contains at least a thermoplastic resin and a titanium dioxide pigment, and the titanium dioxide pigment is manufactured by spray drying, and is determined in accordance with JIS K 5101-1991. A photographic material support having an apparent density (static standing method) of 0.32 g / cm ³ or more. 2. Titanium dioxide pigments whose surface contains from 0.25% to 1.5% by weight, calculated as anhydrous metal oxides per titanium dioxide, of at least aluminum atoms and having a silicon dioxide content of 0%. 2. A material treated with not more than 0.4% by weight (including 0) of a hydrated metal oxide.
The support for the photographic material according to the above. 3. The photographic material support according to claim 1, wherein the titanium dioxide pigment is prepared by an external seed method. 4. The titanium dioxide pigment has a particle diameter of 0.11 as a number average diameter as measured by a directional measurement with an electron microscope.
4. The composition of claim 1, 2 or 3, wherein the thickness is from 0 to 0.150 μm.
The support for the photographic material according to the above. 5. The photograph according to claim 1, wherein the surface of the titanium dioxide pigment is treated with 0.05 to 4.0% by weight of an organic substance per titanium dioxide. Support for materials. 6. The support according to claim 1, wherein the titanium dioxide pigment has an anatase structure. 7. The photographic material support according to claim 1, wherein the thermoplastic resin (A) is a polyolefin resin, a polyester resin or a mixture thereof. 8. A film-forming resin (B) having a paper substrate side opposite to the side covered with the thermoplastic resin (A) layer.
7. The coating according to claim 1, 2, 3, 4, 5, or 6.
Or the support for photographic material according to 7.