JPH032749A - Photographic substrate - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention relates to a resin-coated paper-type photographic support in which at least one side of a paper, synthetic paper or film substrate is coated with a polyolefin resin containing a titanium dioxide pigment. More specifically, the present invention relates to an excellent photographic support that has high sharpness of printed images, extremely little generation of gripp stains during the production of the photographic support, and therefore good surface quality.

[Prior art]

As a photographic support, a resin-coated paper-type photographic support in which at least one side of the substrate is coated with a resin composition comprising at least a tan dioxide pigment and a polyolefin resin is well known. For example, U.S. Patent No. 3.501,2
No. 98 discloses a technique for a photographic support in which both sides of a paper substrate are coated with a polyolefin resin. Furthermore, since rapid photographic processing was applied, photographic supports in which both sides of base paper for photographic paper are coated with polyethylene resin have been mainly used for photographic paper, and image formation on one side The side resin layer usually contains a titanium dioxide pigment to impart sharpness.

Conventionally, anatase-type and rutile-type titanium dioxide pigments are known as titanium dioxide pigments contained in the resin layer on the image forming side of a resin-coated paper-type photographic support. In addition, titanium dioxide pigments whose surfaces are not coated, or titanium dioxide particles whose surfaces are hydrated aluminum oxide, such as those described or exemplified in JP-A-52-35625 and JP-A-57-108849, Titanium dioxide pigment coated with a hydrous metal oxide such as hydrous silicon oxide, and also JP-A-52-35625
No., Special Publication No. 58-43734, Special Publication No. 61-2655
Titanium dioxide pigments are known in which the surface of titanium dioxide particles is coated with an organic substance such as polyhydric alcohol, its derivative, polyorganosiloxane or its derivative, as described or exemplified in No. 2, etc. .

On the other hand, if particularly high sharpness of the printed image is required as a photographic support, some resin-coated paper-type photographic supports are also known.

For example, (1) a resin layer containing a titanium dioxide pigment at a high concentration, (2) a resin layer containing a rutile-type titanium dioxide pigment, (3) a resin layer containing a rutile-type titanium dioxide pigment, and (3) a resin layer containing titanium dioxide pigment in a high concentration. As described in No. 43734, etc., a resin layer containing a titanium dioxide pigment by adding a surfactant represented by a metal soap such as zinc stearate, calcium stearate, or zinc palmitate; (4) resin As the titanium dioxide pigment in the layer, a so-called organically treated titanium dioxide pigment whose particle surface is coated with the above-mentioned organic substance is known.

However, these resin-coated paper-type photographic supports
The reality is that the intended sharpness is insufficient, and there are other serious problems with photographic suitability and manufacturing suitability, and satisfactory results have not yet been achieved.

First, if the concentration of titanium dioxide pigment in the resin layer of the polyolefin resin-coated paper-type photographic support is increased,
Although photographic supports with high print image sharpness can be obtained, serious problems in photographic suitability and manufacturability often occur. That is, when a polyolefin resin composition containing a titanium dioxide pigment, especially a polyethylene resin composition, is melt-extruded onto a substrate from a slit die in the form of a film, a needle-like or icicle-like shape is formed at the tip of the gripp by short-time extrusion. Die-lip stains (hereinafter referred to simply as die-lip stains) tend to occur, and to make matters worse, these die-lip stains tend to grow larger and larger as the melt extrusion time progresses.

If this greasy stain occurs during melt extrusion coating, vertical streaks may appear on the surface of the polyolefin resin-coated paper produced as is, or streak-like unevenness may occur due to uneven coating amount. Sometimes, dirt is attached to the film and coated, and foreign matter appears. As a result, the surface quality of polyolefin resin-coated paper is significantly impaired.
The problem was that it was completely unsuitable as a photographic support that required excellent surface quality and had no commercial value. In addition, the only way to completely remove the grime caused by the die lip is to stop production and clean the die lip or replace the die, and cleaning or replacing the die requires a great deal of effort and time. , there was a problem in that it caused a significant decrease in productivity.

In the first place, the titanium dioxide pigment in the resin layer of a polyolefin resin-coated paper-type photographic support has strict quality requirements, so the surface of the titanium dioxide particles is coated with a hydrous metal oxide such as hydrous aluminum oxide or hydrous silicon oxide. Treated titanium dioxide pigments (hereinafter simply referred to as hydrous metal oxide treated titanium dioxide pigments) are mainly used.
So-called untreated titanium dioxide pigments, which have not been subjected to any surface treatment, are not often used. However, when a titanium dioxide pigment treated with a hydrous metal oxide is used, the more highly the hydrous metal oxide treatment is performed, the more severe the occurrence of grip stain becomes. On the other hand, when untreated titanium dioxide pigment is used, there is less occurrence of gripp stains, but
The resin layer undergoes significant photodeterioration and is prone to discoloration over time.

In order to solve these problems, for example, Japanese Patent Laid-Open No. 57-108849 discloses a photographic support in which a titanium dioxide pigment whose surface is lightly treated with hydrous aluminum oxide is applied to titanium dioxide. ing. However, even with this technique, when the titanium dioxide pigment in the polyolefin resin composition is increased considerably in order to achieve high sharpness of the printed image, there is a problem in that a certain amount of gristle stain occurs.

Second, when a rutile-type titanium dioxide pigment is used as the titanium dioxide pigment contained in the resin layer of a polyolefin resin-coated paper-type photographic support, the print quality is lower than when an anatase-type titanium dioxide pigment is used. Although photographic supports with fairly high image sharpness are obtained, other serious photographic suitability problems arise. That is, the resin surface containing the titanium dioxide pigment on the image forming side of the photographic support has a yellowish tinge due to the rutile titanium dioxide, making it impossible to obtain a photographic support with clear whiteness, resulting in a bright white background. There was a problem that prints could not be obtained.

Thirdly, as a result of studies by the present inventors, when incorporating a titanium dioxide pigment into the resin layer of a paper-type photographic support coated with a polyolefin resin, metal soaps such as zinc stearate, calcium stearate, and zinc palmitate are used. It has been found that there is a problem in that even if a surfactant such as typified by the following is added, the sharpness of the printed image of the photographic support is not substantially improved at all.

In general, a method for incorporating titanium dioxide pigment into the resin layer of a paper-type photographic support coated with a polyolefin resin is to pre-incorporate the pigment using a conventional melt-kneading machine such as a Banbury mixer or an extruder for kneading. A so-called masterbatch containing pigment at a high concentration in the resin is prepared, and then a polyolefin resin composition is diluted and mixed with a diluted resin to the desired ratio, and then a polyolefin resin composition is melt-extruded, or the pigment is mixed in the resin at a desired level from the beginning. It is usual to prepare a so-called compound containing only the following composition ratio and apply it by melt extrusion. In addition, the main purpose of the metal soap originally added to the resin layer of a paper-type photographic support coated with a polyolefin resin is when the photographic support is manufactured by melt extrusion coating. and the resin-coated surface.

However, as a result of studies conducted by the present inventors, completely new findings regarding the effects of metal soap in the resin layer were discovered. That is, the concentration of metal soap added when preparing a titanium dioxide pigment masterbatch or compound in the resin layer of a polyolefin resin-coated paper type photographic support is 1.5% by weight based on the titanium dioxide pigment. , and the sharpness of the printed image of the photographic support increases up to 0.15% by weight based on the resin composition, but at this content m,
Poor releasability, and 1.
At a content in the range of 5% to 7.5% by weight, and 0.15% to 0.75% by weight based on the resin composition, the releasability is improved as the amount added increases; It has been found that the sharpness of the printed image on the photographic support is considerably lower, sometimes even lower than without the metal soap.

Furthermore, if the content is higher than that, the sharpness of the printed image on the photographic support will gradually decrease with the amount added.
It was found that the generation of oil smoke increased and the manufacturing suitability during melt extrusion coating became extremely poor. As described above, even if metal soap is added when blending titanium dioxide pigment into the resin layer of a polyolefin resin-coated paper-type photographic support, a photographic support with high print image sharpness cannot be obtained. There was a problem.

Fourthly, as a result of studies by the present inventors, it has been found that even if a so-called organically treated titanium dioxide pigment is used as the titanium dioxide pigment contained in the resin layer of a paper-type photographic support coated with a polyolefin resin, the photographic support It has been found that there is a problem in that the sharpness of the body print image is not substantially high at all. That is, a metal soap such as zinc stearate is added to the resin layer of a paper-type photographic support coated with a polyolefin resin together with an organically treated titanium dioxide pigment in an amount that will exhibit sufficient releasability during the production of the photographic support. When added, the problem is that the sharpness of the printed image on the photographic support is only about the same or only slightly higher than when using titanium dioxide pigments without organic treatment. There was found.

[Problem that the invention seeks to solve]

Therefore, an object of the present invention is to produce a photographic support in which at least one side of a paper, synthetic paper or film substrate is coated with a polyolefin resin composition containing a titanium dioxide pigment, and which provides high sharpness of photographic print images. It is an object of the present invention to provide an excellent photographic support which has very little occurrence of gristle stains and therefore has good surface quality.

[Means and Effects for Solving the Problems] In order to solve the above-mentioned problems, the present inventors have made extensive studies and found that at least one side of the paper, synthetic paper or film substrate is made of a polyolefin resin composition. In the coated resin-coated paper-type photographic support, the polyolefin resin composition contains at least (A) titanium dioxide having a particle diameter of 0.110 μm to 0.150 μm expressed as a number average diameter in directional measurement using an electron microscope; is a pigment, and on its particle surface contains 0.004% by weight to 0, calculated in the form of metal per titanium dioxide.
It has been found that the objects of the invention are achieved by a photographic support containing a titanium dioxide pigment carrying 1% by weight of a magnesium, calcium or barium compound and (B) an antioxidant.

Furthermore, the present invention can advantageously provide a more preferable resin-coated paper-type photographic support. That is, as a result of studies by the present inventors, it has been found that at least one surface of a paper, synthetic paper, or film substrate is coated with a polyolefin resin composition on the side containing the titanium dioxide pigment of a resin-coated paper-type photographic support. In order to improve the whiteness of the resin layer, the polyolefin resin composition contains a titanium dioxide pigment, especially a titanium dioxide pigment treated with a hydrous metal oxide, and a fluorescent agent, in particular, for example,
-51336 or e.g. U.S. Pat. No. 4,794.
When a resin-coated paper-type photographic support containing a bis(benzooxazolyl)stilbene fluorescent agent such as that described in No. It has been found that when a coloring pigment or coloring dye, in particular an inorganic coloring pigment, is contained, there is a problem in that the occurrence of gripp stain is further promoted. However, according to the present invention, the polyolefin resin composition contains (A) the specific titanium dioxide pigment of the present invention, (B) an antioxidant, and (C) a fluorescent agent, particularly a bis(benzoxazolyl)naphthalene fluorescent agent, or Screw(
(benzoxazolyl) stilbene fluorescent agent and/or (D) a colored pigment or colored dye, especially an inorganic colored pigment, when manufacturing a photographic support in which the resin composition is coated on a substrate. A resin-coated paper type photograph with an excellent layer that generates very little dirt, therefore has good surface quality, high sharpness of printed images, high brightness, looks white, and has good whiteness stability. It has been found that it is possible to provide a support for

The titanium dioxide pigment used in the practice of the present invention includes:
The particle size is expressed as a number average diameter measured in a direction using an electron microscope, and is from 0 to 0 to 150 μm,
And if it carries 0.004% to 0.1% by weight of a magnesium compound, calcium compound or barium compound calculated in the form of metal per titanium dioxide on the particle surface, it is considered to have a rutile structure or anatase. Structures, mixed crystals with rutile structure and anatase structure, or mixtures thereof, and those made by the sulfuric acid method or the chlorine method can be used, but photographs with particularly high print image sharpness can be used. In order to obtain a support for
Those with rutile structure are preferred. Note that titanium dioxide having a rutile structure (hereinafter simply referred to as rutile-type titanium dioxide) as used herein is one in which 90% by weight or more, preferably 95% by weight, of its crystal structure has a rutile structure. In addition, the number average diameter measured in a directional measurement using an electron microscope in this specification is a value obtained by averaging the lengths of 1000 titanium dioxide pigment particles by directional measurement using an electron microscope. It is expressed in μm.

As a typical method for producing the titanium dioxide pigment used in the practice of the present invention, the sulfuric acid method can be produced by the following steps.

Raw ore → Digestion/extraction → Standing/crystallization → Filtration/concentration → Hydrolysis → Washing → Calcining → Grinding/Sizing → Wet grinding/classification → Surface treatment → Washing/drying → Finish grinding → Titanium dioxide pigment. In the case of the sulfuric acid method, iron sulfate is usually crystallized from a solution of ilmenite treated with sulfuric acid, and the separated titanyl sulfate aqueous solution is hydrolyzed to form hydrous titanium oxide, which is then calcined to develop its pigment properties. . Hydrolysis of titanyl sulfate aqueous solution can be carried out either by adding a titanyl sulfate solution to hot water and precipitating hydrous titanium oxide as seeds, or by using titanium sulfate or titanium tetrachloride made by neutralizing it. This can be carried out by a so-called external seeding method in which hydroxide is added as a seed. In addition, when producing a rutile structure, the firing temperature may be set to a higher temperature than when producing an anatase structure, or sodium, potassium, zinc, etc. may be used to promote the formation of the rutile structure during firing. It is carried out at 800 to 1100°C in the presence of a metal compound.

On the other hand, in the case of the chlorine method, titanium dioxide particles are formed by vapor phase sintering decomposition of titanium tetrachloride at high temperature in an oxygen atmosphere, and generally have a rutile structure, which can be produced by the following steps.

High-purity coal mine or synthetic rutile → chlorination → separation/condensation → purification → preheating → calcining decomposition → separation → crushing/sizing – wet crushing/classification – surface treatment → washing/drying – final crushing → titanium dioxide pigment.

The product produced by calcination or vapor phase calcination decomposition will hereinafter be referred to as titanium dioxide linker. Titanium dioxide linker is dry-pulverized using a centrifugal roller mill such as a Raymond mill or a fluid energy mill such as an air mill, and the pulverized material is suspended in water to form a titanium dioxide slurry, which is then wet-pulverized by being subjected to a wet ball mill or vibration mill. Wet classification is carried out using a continuous horizontal centrifuge and/or passing through a vibrating double deck screen (325 mesh U, S, standard screen), hereafter referred to as fines. A titanium dioxide slurry containing substantially no coarse particles of titanium dioxide is obtained. When the surface of titanium dioxide particles is treated with a hydrous metal oxide, the surface of the titanium dioxide particles is usually treated with a hydrous metal oxide containing at least an aluminum atom for fine particles that are still in a slurry form from which coarse particles have been removed. After surface treatment, filtration with a filter press
A titanium dioxide pigment is produced by washing with water and further pulverizing using an impact pulverizer or/and a fluid energy mill.

The titanium dioxide pigment used in the practice of the present invention has a particle diameter of 0.110 μm to 0.1 μm, expressed as a number average diameter measured in a direction using an electron microscope. Photographic supports coated with polyolefin resin compositions containing titanium dioxide pigments in the range of 150 µm and having a number average diameter smaller than 0.110 µm often generate gripp stains during manufacture, and the sharpness of printed images is impaired. The problem is that the level is getting lower.

On the other hand, a photographic support coated with a polyolefin resin composition containing a titanium dioxide pigment having a number average diameter larger than 0.150 μm has a problem in that the sharpness of the printed image becomes considerably low. The titanium dioxide pigment used in the practice of the present invention has a number average diameter of 0.115 μm because it causes very little Glylip stain during the production of photographic supports and provides high sharpness of printed images.
Preferably, the thickness is in the range of 0.135 μm. A titanium dioxide pigment having a number average diameter of 0.110 μm to 0.150 μm can be obtained by manufacturing it under predetermined manufacturing conditions. The manufacturing conditions of the titanium dioxide pigment, particularly the firing temperature, firing time, and the type and amount of inorganic compounds present during firing, such as the inorganic compounds described or exemplified in Japanese Patent Publication No. 18718/1982, and their combined compounds, are as follows: can be determined by measuring the number-average diameter of titanium dioxide pigments produced under a series of combinatorial experimental conditions in a directional electron microscopy measurement. At that time, typical firing conditions that increase the number average diameter are high firing temperature, long firing time, and small amount of inorganic compounds present during firing, while firing conditions that decrease the number average diameter Typical conditions are low firing temperature, short firing time, and large amount of inorganic compounds present during firing. The firing conditions for the titanium dioxide pigment used in the practice of the present invention include a firing temperature of 800°C to 1100°C, a firing time of 15 minutes to 5 hours, and an amount of inorganic compounds present.
0 per titanium dioxide, calculated in the form of inorganic oxides. Particularly preferred are combination conditions in the range 2% to 5% by weight.

The titanium dioxide pigment used in the practice of this invention has a particle surface of 0.00, calculated in the form of metal per titanium dioxide.
It is manufactured by supporting at least one compound of a magnesium compound, a calcium compound, or a barium compound in an amount of 4% by weight to 0.1% by weight. If the amount supported on the surface of the titanium dioxide particles is less than 0.004% by weight, photographic supports coated with a polyolefin resin composition containing the titanium dioxide pigment will often develop gristle stains during manufacture, resulting in poor sharpness of printed images. The problem is that the level is getting lower. On the other hand, if the supported amount is more than 0.1% by weight, the photographic support coated with the polyolefin resin composition containing the titanium dioxide pigment will also tend to generate grip stains during its manufacture, and the printed image will deteriorate. The problem is that the sharpness becomes low. A preferred loading range is from 0.006% to 0.07% by weight, calculated in metallic form relative to titanium dioxide. The calcium compound, magnesium compound, or barium compound supported on the surface of the titanium dioxide particles is preferably a water-soluble salt, but may be an oxide or hydroxide. Specific examples thereof include calcium chloride, magnesium chloride, magnesium sulfate, barium chloride, calcium hydroxide, calcium oxide, magnesium hydroxide, magnesium oxide,
Examples include barium hydroxide, barium oxide, calcium acetate, magnesium acetate, calcium citrate, magnesium citrate, calcium carbonate, and magnesium carbonate.

In addition, as a method for supporting a calcium compound, a magnesium compound, or a barium compound on the surface of titanium dioxide particles, in the manufacturing process of titanium dioxide pigment, the process after the step of suspending the pulverized titanium dioxide linker in water to form a titanium dioxide slurry This is carried out by allowing these compounds to coexist in the titanium dioxide slurry at any stage. Preferably, this is carried out by adding an aqueous solution or suspension of these compounds to the titanium dioxide slurry at any stage after the wet grinding/classification step, allowing them to coexist, and thus adsorbing them onto the surfaces of the titanium dioxide particles.

In addition, as a result of studies by the present inventors, the amount of magnesium compounds, calcium compounds, or barium compounds supported on the surface of titanium dioxide particles is determined by the type and amount of these compounds, the particle size of titanium dioxide, the specific surface area, and the crystal shape. , properties and conditions of titanium dioxide particles such as crystal structure, type and amount of surface treatment with hydrous metal oxide, pH1 temperature of titanium dioxide slurry, slurry conditions such as concentration, addition conditions such as at what stage to add, etc. It turns out that this is determined by factors or conditions. Therefore, the specific manufacturing conditions, especially the type and amount of magnesium compound, calcium compound, or barium compound added, are as follows for titanium dioxide pigments manufactured under a series of combination experimental conditions. It is determined by analytically determining the amount of these compounds supported on the surface of the pigment while examining the performance of the polyolefin resin-coated paper-type photographic support. The amount of these compounds supported on the surface of the titanium dioxide particles is usually a considerably lower value than the amount added to the titanium dioxide slurry. Note that the amount of magnesium compound, calcium compound, or barium compound supported on the surface of the titanium dioxide particles as referred to in this specification is specifically determined analytically by the following method.

Precisely weigh 1.0000 g of sample titanium dioxide pigment, put it in a crucible, and add 10 ml of special grade 36% by weight hydrochloric acid solution.
, put a lid on the crucible and heat it on a sand bath at 360℃
Heat at ±20°C for 15 minutes, cool and filter (if filtration is incomplete, use centrifugation). Then, add 10ml of special grade 36% by weight hydrochloric acid solution to 490ml of distilled water.
Wash with 10 ml of diluted hydrochloric acid diluted with 10 ml of diluted hydrochloric acid, add 3 ml of distilled water containing 3 wt.
Adjust it to the following and use it as the test solution. Measure the test solution by atomic absorption method,
The concentration of calcium, magnesium, or barium in the test solution is determined using a calibration curve determined in advance, and the amount of these compounds supported on the surface of the titanium dioxide pigment particles is thus determined.

The titanium dioxide pigment used in the practice of the present invention includes:
Particles whose surfaces are surface-treated with a specific amount of a hydrous metal oxide containing at least aluminum atoms, or particles whose interiors are internally treated with at least a specific amount of an aluminum compound, are advantageously used; It may also be subjected to a combination of internal processing. Furthermore, in the case of a material that has been internally treated, it may be one that has not been surface-treated. In particular, when using the sulfuric acid method, from the viewpoint of designing titanium dioxide pigments, it is useful to have the particle surface treated with a hydrous metal oxide containing at least a specific amount of aluminum atoms.

The titanium dioxide pigment that is surface-treated with a hydrous metal oxide, which is advantageously used in the practice of the present invention, has a particle surface of 0% in the form of anhydrous metal oxide per titanium dioxide after wet grinding and classification of titanium dioxide.゜Contains at least aluminum atoms in an amount of more than 2% by weight and less than 1.8% by weight, and is treated with a hydrous metal oxide of 0.4% by weight or less (including 0) as a silicon dioxide skeleton Useful. The amount of titanium dioxide surface treated is 0. If it is less than 2% by weight, the weather resistance of the resin layer of the resin-coated paper containing the titanium dioxide pigment becomes poor, which is a problem. On the other hand, if the treatment amount is 1.8% by weight or more, the occurrence of gripp stain becomes significant, which is a problem. The preferred treatment amount range is from 0.35% to 1% by weight of titanium dioxide in the form of anhydrous metal oxide.
．． 5% by weight, particularly preferably from 0.5% to 1.5% by weight.
It is in the range of 0% by weight. The silicon dioxide bones containing at least aluminum atoms are preferably surface-treated with hydrous aluminum oxide as the hydrated metal oxide of 0.4% by weight or less (including 0), and if necessary, the silicon dioxide bones are further treated with hydrated aluminum oxide. less than 0.4% by weight, preferably less than 0.2% by weight of hydrated silicon oxide, or other hydrated metal oxides such as hydrated titanium oxide with a total amount of less than 1.8% by weight of anhydrous metal oxides. Alternatively, the surface can be treated with hydrous silicon aluminum oxide containing less than 0.4% by weight of silicon dioxide.

In addition, as a method for treating the surface of titanium dioxide particles with a hydrous metal oxide, titanium dioxide slurry is wet-pulverized.
After classification, the pH is adjusted to 5 or higher, preferably 6 or higher, particularly preferably around 7, and then a water-soluble aluminum salt, if necessary, other water-soluble metal salts or water-soluble silicon compounds are added to the titanium dioxide slurry, and then By changing the pH in the slurry, poorly soluble hydrated aluminum oxide and, if necessary, other poorly soluble oxide hydrates can be precipitated onto the titanium dioxide pigment for surface treatment.

For example, a typical method for surface treatment in a reaction treatment tank equipped with a stirrer is to add a water-soluble alkaline solution such as caustic soda or potassium hydroxide to titanium dioxide slurry after wet grinding and classification. Slurry pH
7.0±1. Adjust to 0. Add an aluminate such as alkali aluminate to the pH-adjusted titanium dioxide slurry, and if necessary, add an aqueous solution of a water-soluble alkali such as caustic soda or potassium hydroxide, then reduce the pH to an alkaline slurry. In order to precipitate hydrous aluminum oxide on the surface of the titanium dioxide particles, the surfaces are treated by adding, for example, an aqueous solution of a mineral acid such as sulfuric acid or hydrochloric acid or a salt that exhibits an acidic reaction. The pH of the titanium dioxide slurry after surface treatment is usually in the range of 7.0±1.0. Moreover, among alkali aluminates, sodium aluminate is particularly useful. In addition to the aluminate, the surface can be treated with other inorganic surface treatment agents. 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 aluminate used for these surface treatments include silicon compounds such as alkali silicate,
Various types of titanium compounds such as silicon tetrachloride, metal compounds such as zirconium, zinc, and manganese, and phosphoric acid compounds can be used in addition to titanium tetrachloride.

Furthermore, titanium dioxide pigments which are advantageously used in the practice of the present invention and which have been internally treated with an aluminum compound have a particle interior that has an AI value per titanium dioxide! Those internally treated with at least an aluminum compound in an amount of more than 0.2% by weight and less than 1.8% by weight, calculated in the form of 203, are useful. The processing amount of titanium dioxide inside is 0.2% by weight.
If it is less than that, the weather resistance of the resin layer of the resin-coated paper containing the titanium dioxide pigment becomes poor, which is a problem. On the other hand, if the treatment amount is 1.8% by weight or more, die lip stains will occur more frequently, which is a problem. The preferred treatment amount range is AI! for titanium dioxide. , 2°3, ranges from 0.35% to 1.5% by weight. In the case of the sulfuric acid method, aluminum compounds used for internal treatment of titanium dioxide particles include, for example, aluminum chloride,
Aluminum compounds such as aluminum sulfate, aluminum hydroxide, and sodium aluminate are preferred, with aluminum chloride and aluminum sulfate being preferred. Furthermore, in the case of the chlorine method, aluminum chloride is preferred.

In addition, as a method for treating the inside of titanium dioxide particles with an aluminum compound, in the case of the sulfuric acid method, this is done by adding an aluminum compound before the calcination process, but the preferred process is to wash it after hydrolysis and then filter it. Place the concentrated hydrous titanium oxide in a mixer, such as a Nigu, and add an aluminum compound and mix well, or redisperse it in water in a mixing tank equipped with a stirrer, add the aluminum compound, and mix well. After that, it is made through a firing process. In the case of the chlorine method, for example, U.S. Pat.
No. 21,641, by feeding an aluminum compound, preferably aluminum chloride, simultaneously with titanium tetrachloride and oxygen during the calcining process.

The titanium dioxide pigment used in the practice of the present invention can be used on the surface of a resin-coated paper-type photographic support containing the pigment in its resin layer after surface treatment or by internal treatment alone in order to further increase the sharpness of printed images on a resin-coated paper-type photographic support. Those without treatment are manufactured by wet-pulverizing, φ-classifying, supporting a calcium compound, magnesium compound, or barium compound, and then washing with water until the electrical conductivity of the suspension becomes 60 μσ/cm or less as described below. is preferred. The electrical conductivity of a suspension of titanium dioxide pigment herein is defined as follows.

After adding 10.0 g of titanium dioxide pigment to 100 ml of distilled water in a 100 ml beaker, the contents in the beaker were brought to a liquid temperature of 21°C by stirring power using a rotor (rotation speed: 42 Orpm/min) on a magnetic scooter. .5℃±0
．． Stir for 16 minutes while maintaining the temperature at 5°C to form a titanium dioxide pigment suspension. Sixteen minutes after the start of stirring, the electrical conductivity of the titanium dioxide pigment suspension is measured at 21.5° C.±0.5° C. using an electrical conductivity meter while stirring the suspension. The electrical conductivity thus obtained is defined as the titanium dioxide pigment suspension electrical conductivity in this specification.

The electrical conductivity of the suspension advantageously used in the practice of the invention is 6.
Titanium dioxide pigments with a particle size of 0 μtJ/cm or less are subjected to surface treatment, or those with internal treatment without surface treatment are wet-pulverized and classified, then loaded with calcium compounds, magnesium compounds, or barium compounds, and then subjected to the initial process using a filter press. After filtering the mother liquor and subsequently washing and drying the titanium dioxide cake with water, in order to further increase the sharpness of the printed image of the titanium dioxide body in the filter press,
Advantageously, it is produced by comminution in a fluid energy mill. As the fluid energy mill, a steam mill such as a micronizer is particularly preferred, but an air mill can also be used in combination. Furthermore, before pulverization is performed using a fluid energy mill, it is particularly preferable to perform a first stage pulverization using an impact pulverizer such as a hammer mill, and then perform pulverization using a fluid energy mill as a second stage pulverization.

The titanium dioxide pigment used in the practice of the present invention is, of course,
If necessary, various organic treatments with triethanolamine, trimethylolpropane, fatty acid metal salts, organopolysiloxane, etc. may be performed.

The antioxidant used in the practice of the present invention is one that does not cause any problems when added to the resin composition constituting the resin layer on the side where the image is formed of the resin-coated paper-type photographic support. , phenol-based, amine-based, or phosphoric acid ester-based antioxidant cakes under running water at 60μ*
It is produced by washing with water until a titanium dioxide pigment with a suspension electrical conductivity of less than / cm is obtained. Washing conditions such as washing time, amount of water, and pressure of water were determined by subjecting the titanium dioxide cake collected under a series of combined experimental conditions to subsequent processing of drying and pulverization to obtain a titanium dioxide pigment. It can be determined by measuring the electrical conductivity of the suspension. Washing with water is
The titanium dioxide-containing slurry can be used as is, or the filter cake can be resuspended in a tank and then washed with running water, such as by replacing the pooled water or supernatant liquid, in conjunction with or separately from rinsing in the filter press. You can also do that. Furthermore, in order to further increase the sharpness of printed images on photographic supports, the titanium dioxide pigment used in the practice of the present invention preferably has a suspension electrical conductivity of 55 μΦ/ca or less, particularly 50 μQ/ca. More preferably, the diameter is less than cm.

The titanium dioxide pigment used in the practice of the present invention can be used in a resin-coated paper-type photographic support containing the pigment in the resin layer, but it does not have a negative effect on the photographic emulsion layer and is more effective against grip stains. Hindered phenol-based antioxidants are particularly suitable because they can prevent this from occurring. The hindered phenolic antioxidants that are advantageously used include, for example, 1,3.5-trimethyl-2,4,
6-tris(3,5-di1e++-butyl-4-hydroxybenzyl)benzene, tetrakis[methylene(3
,5-di-1e+t-butyl-4-hydroxy-hydrocinnamate)] Methane, octadecyl-3,5-di-terl-butyl-4-hydroxy-hydrocinnamate, 2.2',2'-1lis [(3゜5-G 1e
rl-butyl-4-hydroxyphenyl)propionyloxy]ethyl isocyanurate, 1, 3. 5-)
Lis(4-lefl-butyl-3-hydroxy-2,6
-di-methylbenzyl)isocyanurate, tetrakis(2,4-di-1erl~butylphenyl) 4. 4
' -biphenylene diphosphite, 4.4'-
Thiobis-(6-ferl-butyl-0-cresol)
, 2,2'-thiobis(6-1ut-butyl-4-
methylphenol), tris-(2-methyl-4-hydroxy-5-(c"1-butylphenyl)butane, 2.
2'-methylene-bis-(4-methyl-6-te
n+-butylphenol), 4.4'-methylene-bis-(2,6-di-1eft-butylphenol), 4.
4'-butylidenebis-(3-methyl-5-1al
l-butylphenol), 2,6-di1e[(-butyl-4methylphenol, 4-hydroxy methyl-2
゜6-di-1erl-butylphenol, 2,6-dif
Examples include e+l-4-n-butylphenol.

Furthermore, two or more kinds of antioxidants may be used in combination depending on the properties of the antioxidants.

The content of the antioxidant in the polyolefin resin composition is preferably 10% by weight in the resin composition.
~tooppm, particularly preferably 20~
It is in the range of 500 ppm. Antioxidant amount is 5ppm
Even if it is less than 11,000 pp, if it is more than 11,000 pp, Grip stain tends to occur, and if it is more than 11,000 pp, the adhesion between the base paper and the resin layer tends to deteriorate.

In addition, as a method for incorporating an antioxidant into the resin composition, it is possible to use a so-called compound in which the antioxidant is pre-contained in the polyolefin resin to be used, or to add the antioxidant to a relatively high concentration. An appropriate amount of the resin may be used, or an antioxidant may be added when producing the resin composition using a kneader. Furthermore, depending on the type and content of the antioxidant used, the above methods may be combined as appropriate.

Polyolefin resins used in the present invention include homopolymers such as polyethylene, polypropylene, polybutene, and polypentene, and copolymers consisting of two or more α-olefins such as ethylene-propylene copolymers and ethylene-butylene copolymers. Among these, polyethylene resins are preferred from the viewpoint of melt extrusion coating properties and economic efficiency. These polyethylene resins include low-density polyethylene, medium-density polyethylene, high-density polyethylene, linear low-density polyethylene, copolymers of ethylene and α-olefins such as propylene and butylene, carboxy-modified polyethylene, etc. It is a mixture, and can have various densities, melt flow rates (hereinafter simply referred to as MFR), molecular weights, and molecular weight distributions, but it usually has a density of 0.90 g/m3 to 0.9 g/m3.
Range of 7g/m3, MFR1g/10min~30g
/10 minutes, preferably an MFR of 3 g/10 minutes to 15 g/minute, and a molecular weight of 20,000 to 250,000, which can be advantageously used alone or in combination. In addition, when the resin has a multilayer structure, the outermost layer resin may have an MFR of 5 to 20 g/10, for example.
For example, as the lower layer resin, MFR2~Log
It is also possible to use resins with other properties and compositions, such as those with a diameter of /10 minutes.

The method for incorporating the titanium dioxide pigment used in the practice of the present invention into the resin layer of the resin-coated paper-type photographic support is to prepare a so-called masterbatch in which the titanium dioxide pigment is previously contained in a polyolefin resin at a certain concentration. Then, use a resin composition in which they are diluted and mixed in a desired ratio with a diluent resin, or create and use a so-called compound in which titanium dioxide pigment is contained in a polyolefin resin in a desired composition ratio from the beginning. is normal. To create these masterbatches and compounds, a Banbury mixer, a kneader-1 kneading extruder, a two-roll kneader, a three-roll kneader, etc. are usually used. Used to advantage. or,
Two or more of these various kneaders may be used in combination.

In addition, in order to improve the releasability during the production of the resin-coated paper-type photographic support in the present invention, fatty acid metal salts are added to the masterbatch or compound of the titanium dioxide pigment when the photographic resin is prepared. Preferably, a fatty acid metal salt is contained in the resin layer of the coated paper. Examples of these fatty acid metal salts include zinc stearate, calcium stearate, aluminum stearate, magnesium stearate, zirconium octylate, sodium palmitate, calcium palmitate, and sodium uronate.

The amount added is in the range of 0.1% to 50% by weight for the titanium dioxide pigment, and 0.01% to 5% by weight for the resin layer containing the titanium dioxide pigment. A range is preferred.

The content of titanium dioxide pigment contained in the resin layer of the resin-coated paper-type photographic support in the present invention is 7% by weight or less based on the resin, so that the sharpness of the printed image can be improved as a photographic support. insufficient, while 35% by weight
If the amount is more than that, the fluidity will be lowered, the extrusion properties will be deteriorated, and die lip stains will become noticeable, which is undesirable.The range of 9% to 30% by weight is particularly preferable. In the resin layer of the resin-coated paper-type photographic support in the present invention,
In order to improve the yellowness caused by titanium dioxide pigments, especially titanium dioxide pigments that are contained in high concentrations in the resin layer in order to obtain high sharpness, and to provide excellent whiteness.
It is preferable to contain a fluorescent agent. These fluorescent agents include naphthalene-based, stilbene-based, thiophene-based,
Various fluorescent agents such as coumarin type can be used, but the effectiveness of improving whiteness, dispersibility of the fluorescent agent in polyolefin resin, heat resistance, bleed-out resistance, weather resistance, stability in photographic processing solutions, etc. From this point of view, a bis(benzoxazolyl)naphthalene fluorescent agent and/or a bis(benzooxazolyl)stilbene fluorescent agent having a substituent is preferable. Specific examples of naphthalene-based fluorescent agents and stilbene-based fluorescent agents that are advantageously used include those represented by the following formulas. In the case of naphthalene-based fluorescent agents, the number of carbon atoms is 0 from the viewpoint of bleed-out resistance.
Those having 6 or more substituents are preferred.

(Left below) (n) H2sC+z (1) H1□08 83C In addition, as a method for incorporating these fluorescent agents into the polyolefin resin composition, when manufacturing a masterbatch or compound of titanium dioxide pigment, the fluorescent agent It is also possible to create a masterbatch or compound consisting of a titanium dioxide pigment, a fluorescent agent, a polyolefin resin, a dispersant such as a fatty acid metal salt, and to incorporate it into the resin composition. A resin composition is prepared by preparing a fluorescent agent masterbatch in which a fluorescent agent premixed with a low molecular weight polyolefin having a low softening point and solid at room temperature or/and a dispersing agent such as a fatty acid metal salt is dispersed in a main polyolefin resin. It can be contained inside. In addition, the content of the fluorescent agent in the resin layer of the photographic support should be 0.0000. 3mg/rrf~30
mg/+1? The range is particularly preferably 0. 5
The range is from mg/rrf to 10 mg/rrr.

In the resin layer of the resin-coated paper-type photographic support of the present invention, it is preferable to contain an inorganic or organic blue pigment or blue dye to further whiten the appearance. Specific examples thereof include inorganic compounds such as cobalt blue, navy blue, and ultramarine, and organic compounds such as cerulean blue, phthalocyanine blue, and chromophthalic blue A3R. In addition, the amount added is 1% to the resin layer, and in the case of an inorganic blue pigment, it is in the range of 0.025% to 0.5% by weight, preferably 0.05% to 0.2% by weight. Yes, in the case of organic blue compounds, 0.001% to 0.1% by weight
, preferably in the range of 0.0025% to 0.05% by weight. If the amount added is too small, no coloring effect can be obtained, and if it is too large, not only the brightness will decrease, but also the occurrence of gripp stains will increase, which is not preferable.

Furthermore, it is advantageous to contain an inorganic or organic magenta pigment or magenta dye in the resin layer of the resin-coated paper-type photographic support of the present invention, if necessary. Specific examples thereof include cobalt violet, fast violet, manganese violet, reddish ultramarine, and quinacridone red. In the case of an inorganic magenta pigment, the amount added to the resin layer is 0.025% to 1.0% by weight, preferably 0.
．． The content ranges from 1% by weight to 0.4% by weight, and in the case of organic magenta compounds, from 0.001% to 0.03% by weight, preferably from 0.002% to 0.015% by weight.

The resin-coated paper-type photographic support in the present invention contains the titanium dioxide pigment and antioxidant in the present invention,
More preferably, it has a resin layer containing the above-mentioned fatty acid metal salt, fluorescent agent, inorganic or organic coloring pigment, or coloring dye, but when the resin layer has a multilayer structure, the resin layer in the present invention Other resin layers may also contain the titanium dioxide pigments, antioxidants, fatty acid metal salts, fluorescent agents, colored pigments, or colored dyes. Also,
The resin layer on the side on which the image is formed and the resin layer on the opposite side of the photographic support in the present invention contain the above-mentioned titanium dioxide pigment, antioxidant, fatty acid metal salt, fluorescent agent, colored pigment, or colored dye. In addition, titanium dioxide other than the present invention,
White pigments such as zinc oxide, talc, calcium carbonate, fatty acid amides such as stearic acid amide and araxic acid amide, organic silicone compounds such as polyorganosiloxane, Tinuvin 320, Tinuvin 326, Tinuvin 32
It is preferable to add various additives such as ultraviolet absorbers such as No. 8 (trade name of Ciba Geigy) in appropriate combinations.

The photographic support produced according to the present invention is produced by the so-called extrusion coating method, in which a heated and molten polyolefin resin is cast onto a moving substrate such as paper, synthetic paper or film, and usually both sides of the support are coated with the resin. . In the case of a multilayer construction, several resin layers of the photographic support are extrusion coated one after the other, preferably successively, in so-called tandem extrusion coating systems, or several resin layers are extrusion coated simultaneously. Preferably, a so-called co-extrusion coating system is used. Further, before coating the substrate with the resin, it is preferable to subject the substrate to an activation treatment such as a corona discharge treatment or a flame treatment. The surface of the emulsion side of the photographic support is a glossy surface or JP-A-55-2650 which does not affect the gloss of the surface of the photographic paper when it is made into photographic paper.
It has a finely rough surface, a matte surface, a grain surface, etc. as described in No. 7, and the back side is usually a matte surface, and if necessary, the front surface or both the front and back surfaces are subjected to activation treatment such as corona discharge treatment or flame treatment. be able to. Furthermore, after activation treatment, JP-A-6
Undercoating processing as described in No. 1-84643 can be performed.

There is no particular restriction on the thickness of the resin layers on the front and back sides of the resin-coated paper-type photographic support, but it is generally advantageous to extrusion coat the resin layer to a thickness of about 10 to 50 microns.

Substrates used in the practice of the present invention include natural pulp paper made mainly of ordinary natural pulp, mixed paper made of natural pulp and synthetic fibers, synthetic fiber paper made mainly of synthetic fibers, polystyrene, polypropylene, etc. Synthetic paper made from a synthetic resin film, or films made of cellulose acetate, polyethylene terephthalate, polycarbonate, etc., may be used as the substrate for the photographic paper support. Natural pulp paper (hereinafter simply referred to as base paper) is especially preferred because it has a high hardness, no die lip streaks, and therefore can economically advantageously provide an excellent photographic support with good surface quality. Preferably and advantageously used.

The pulp constituting the base paper preferably used in the practice of the present invention includes JP-A-58-37642 and JP-A-60-37642.
No. 67940, JP-A-60-69649, JP-A-61
It is advantageous to use appropriately selected natural pulps such as those described or exemplified in No. 35442.
Synthetic pulp and synthetic fibers other than natural pulp may be used if necessary. Natural pulp is subjected to conventional bleaching treatments such as chlorine, hypochlorite, and chlorine dioxide bleaching, as well as alkali extraction or alkali treatment and, if necessary, oxidative bleaching treatment using hydrogen peroxide, oxygen, etc., and combinations thereof. Wood pulps such as softwood pulp, hardwood pulp, and softwood hardwood mixed pulp are advantageously used, and various pulps such as kraft pulp, sulfide pulp, and soda pulp can also be used.

The base paper preferably used in the practice of the present invention can contain various sizing agents and polymer compounds when preparing the paper stock slurry.

Sizing agents that can be advantageously included in the base paper preferably used in the practice of the present invention include fatty acid metal salts and/or
and fatty acids, alkyl ketene dimers, alkenyl or alkyl succinic anhydrides, JP-A-54-147211
Epoxidized higher fatty acid amide described in JP-A No. 1987-
Examples include organic fluoro compounds described in No. 109343.

Sizing agents that can be advantageously contained in the base paper preferably used in the practice of the present invention include fatty acid metal salts or/ Examples include alkyl ketene dimers or combination sizing agents of alkyl ketene dimers and epoxidized higher fatty acid amides, which are fixed to the pulp with or without fatty acids and water-soluble aluminum salts. The fatty acid metal salt and/or fatty acid preferably have 12 to 22 carbon atoms,
The amount added is preferably in the range of 0.5 to 4.0% by weight based on the absolute dry weight of the pulp.

In addition, the amount of water-soluble aluminum salt added as needed is 1/20 to 4 times the solid weight of the sizing agent.
The range of /1 is particularly preferred, and the range of 1/10 to 1/1 is particularly preferred. Further, as the alkyl ketene dimer, one having an alkyl group having 8 to 30 carbon atoms, preferably 12 to 18 carbon atoms is preferable. Alkyl ketene dimers are usually commercially available in the form of emulsions thereof, and specific examples include Acopel 360XC manufactured by De Socno 1-Cures. The amount added is preferably in the range of 0.2 to 4.0% by weight based on the absolute dry weight of the pulp as the alkyl ketene dimer content.

Examples of polymer compounds that can be advantageously incorporated into the base paper preferably used in the practice of the present invention during the preparation of the paper stock slurry include cationic wet paper strength agents, cationic, anionic or amphoteric paper strength agents. As the cationic wet paper strength agent, polyamine polyamide epichlorohydrin resin is preferable, and the amount added is in the range of 0.05 to 4.0% by weight, particularly 0.15% by weight based on the dry weight of the pulp.
A range of 1.5% by weight is preferred. A specific example is Dick Vercules (Suriso Kaimen 557 H
, Kaimen 5-25, and Evinox P-130.

Examples of cationic, anionic or amphoteric paper strength enhancers include cationic starch described or exemplified in Japanese Patent Publication No. 60-17103, cationic polyvinyl alcohol described or exemplified in Japanese Patent Application No. 62-49699, Cationic polyacrylamide described or exemplified in No. 57-185432 and JP-A No. 57-197539,
Anionic polyacrylamide described or exemplified in Japanese Patent Publication No. 62-23119 and Japanese Patent Publication No. 61-31118,
Examples include amphoteric polyacrylamide described or exemplified in Japanese Patent Publication No. 61-37613 and JP-A-59-31949, and vegetable galactomannan described or exemplified in JP-A-59-125731. The amount of these additives added is preferably in the range of 0.05 to 8% by weight, particularly in the range of 0.15 to 4% by weight, based on the dry weight of the pulp.

In addition, the base paper preferably used for carrying out the present invention includes:
Various additives can be included when preparing the paper stock slurry. Fillers include clay kaolin, calcium carbonate, barium sulfate, magnesium silicate, titanium oxide, etc. pH regulators include caustic soda, soda carbonate, etc.
As a coloring pigment, a coloring dye, and a fluorescent whitening agent, JP-A-54-
No. 147033, patent application No. 1983-37555, patent application No. 1983
The materials described or exemplified in No. 3-96516 may be contained in appropriate combinations.

Various water-soluble polymers, antistatic agents, and additives can be added to the base paper preferably used in the practice of the present invention by spraying or tab size pressing. Water-soluble polymers include starch-based polymers, polyvinyl alcohol-based polymers, gelatin-based polymers, polyacrylamide-based polymers, and cellulose-based polymers as described or exemplified in Japanese Patent Application No. 63-96516. Alkali metal salts such as sodium chloride and potassium chloride as described or exemplified in the No.
Alkaline earth metal salts such as calcium chloride and barium chloride, colloidal metal oxides such as colloidal silica, organic antistatic agents described or exemplified in JP-A-58-82242, latte sox, emulsions, etc. Petroleum resin emulsion, latex such as styrene-acrylic acid-acrylic ester copolymer, styrene-acrylic acid-butadiene copolymer, ethylene-vinyl acetate copolymer, styrene-maleic acid-acrylic ester copolymer, etc., and pigments. As a pH regulator, such as clay, kaolin, talc, barium sulfate, titanium oxide, etc., as a pH controller, hydrochloric acid, phosphoric acid, citric acid, caustic soda, soda carbonate, etc. In addition, the above-mentioned colored pigments, colored dyes, optical brighteners, etc. It is advantageous to include suitable combinations of additives.

For the production of the base paper preferably used in the practice of the present invention, commonly used paper machines such as a Fourdrinier paper machine and a circular net paper machine are used.
It is advantageous to employ suitable papermaking methods, such as those described or exemplified in JP-A-60240 and JP-A-61-284762.

There are no particular restrictions on the thickness of the base paper, but after making the base paper,
Preferably, the base paper is calendered as described or exemplified in No. 6397, and its basis weight is 40 g/
Rrr~250 g/i is preferable.

The photographic support in the present invention can be coated with various back coat layers for antistatic purposes, curl prevention, and the like. In addition, for the back coat layer,
No. 20, Special Publication No. 57-9059, Special Publication No. 57-539
No. 40, Japanese Patent Publication No. 58-56859, Japanese Patent Publication No. 59-21
Inorganic antistatic agents, organic antistatic agents, hydrophilic binders, latexes, curing agents, pigments, surfactants, etc. described or exemplified in No. 4849, JP-A No. 58-184144, etc. can be contained in appropriate combinations. .

The photographic support in the present invention is coated with various photographic constituent layers, and is used for color photographic paper, black and white photographic paper, typesetting photographic paper, copying photographic paper, reversal photographic material, silver salt diffusion transfer. It can be used for a variety of purposes, including for negatives and positives, and for printing materials. For example, silver chloride, silver bromide, silver chlorobromide, silver iodobromide, and silver chloroiodobromide emulsion layers can be provided. A color coupler is contained in the silver halide photographic emulsion layer,
Multilayer silver halide color photographic constituent layers can be provided. Further, a silver salt diffusion transfer image-receiving layer can be provided by containing physical development nuclei. As the binder for these photographic constituent layers, in addition to ordinary gelatin, hydrophilic polymeric substances such as polyvinylpyrrolidone, polyvinyl alcohol, and polysaccharide sulfate ester compounds can be used. Further, the above-mentioned photographic constituent layer can contain various additives. For example, sensitizing dyes include cyanine dyes and merocyanine dyes; chemical sensitizers include water-soluble gold compounds and sulfur compounds; antifoggants and stabilizers include hydroxy-triazolopyrimidine compounds;
mercapto-heterocyclic compounds, formalin, vinyl sulfone compounds, aziridine compounds, etc. as hardening agents,
Coating aids such as benzene sulfonate and sulfosuccinate salts, anti-staining agents such as dialkylnohydroquinone compounds, and optical brighteners, sharpness-enhancing dyes, antistatic agents, pH regulators, and fogging agents. A suitable combination of water-soluble iridium, water-soluble rhodium compounds, etc. can be contained during the production and dispersion of silver halide.

The silver halide photographic material according to the present invention may be exposed, developed, and processed as described in "Photographic Light-sensitive Materials and Handling Methods" (Kyoritsu Shuppan, written by Gobe Miyamoto, Photographic Technology Lecture 2) in accordance with the photographic material. Processes such as stopping, fixing, bleaching, stabilizing, etc. are carried out, and in particular, multilayer silver halide color photographic materials that undergo bath bleach-fixing treatment after color development are CD-m, CD-rV.
(The above two types of compounds are trade names of Kodak Co.), Droxychrome (trade name of May & Beer Co., Ltd.), etc. can be used for processing with any crude drug color developer.

A developing solution containing such a herbal drug may contain a development accelerator such as benzyl alcohol, thallium salt, or phenidone, or it is also possible to process with a developing solution that does not substantially contain benzyl alcohol. Also useful is a one-bath bleach-fix solution containing metal salts of aminopolycarboxylic acids (for example, ferric complex salts such as ethylenediaminetetraacetic acid and propylenediaminetetraacetic acid), and the fixing agents include sodium thiosulfate and ammonium thiosulfate. etc. are useful. Such a one-bath bleach-fix solution may contain various additives. For example, desilvering accelerators (e.g., U.S. Pat. No. 3,512
, mercapto-heterocyclic compounds described in Belgian Patent No. 682,426), antifouling agents, pH regulators or pt-i buffers, hardening agents (e.g. magnesium sulfate), mercapto-heterocyclic compounds described in Belgian Patent No. , aluminum sulfate, potassium alum, etc.), surfactants, and various other compounds can be contained in combination. Also, such -bath bleach-fix solutions may be used at various pHs, but a useful pH range is from pH 6.0 to 8.0.

〔Example〕

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

Example 1 A rutile type titanium dioxide pigment manufactured under predetermined firing conditions to obtain the particle size listed in Table 1 according to the manufacturing process of rutile type titanium dioxide pigment by the sulfuric acid method described in the main text of the specification. The titanium dioxide linker was pulverized and sized, and further wet-pulverized and classified to obtain a titanium dioxide slurry substantially free of coarse titanium dioxide. This slurry was put into a reaction treatment tank, and the amount of calcium compound supported on the surface of titanium dioxide particles was calculated as 0°04 in the form of calcium per titanium dioxide.
10% by weight of CaC12' 6H20 to
Add aqueous solution. Thereafter, the pH of the slurry was raised to about 9.2 with sodium hydroxide, and the temperature of the slurry was raised to about 7.
After heating to 0°C, for dry basis titanium dioxide,
An amount of aqueous sodium aluminate solution, calculated as 0.75% by weight in Al2O3, was added and held for 30 minutes.

The pH of the slurry was then adjusted to 7.0 by adding 20% sulfuric acid.
The slurry was further aged for 2 hours. After ripening,
The initial mother liquor of the titanium dioxide slurry surface-treated with hydrous alumina is filtered through a filter press, and the titanium dioxide cake in the filter press is then washed with running water to form a suspension as defined in the text of the specification for titanium dioxide pigments. Electric conductivity is 45μ? 3/am under predetermined water washing conditions.

After that, the titanium dioxide cake is dried, impact-pulverized with a hammer mill equipped with a metered feeder, and further finely pulverized with a steam mill to produce rutile-type titanium dioxide pigments with different particle sizes that support calcium compounds on the particle surface. did.

Thus, the density is 0. 918 g/cm3, MF R
low density polyethylene with a density of 8.0 g/10 min or a density of 0. 918 g/cm3, MF R is 8.0 g/cm3
10 minutes, 50 parts by weight of low-density polyethylene containing 135 ppm of tetrakis[methylene(3,5-di(C-butyl-4-hydroxy-hydrocinnamate)]methane as an antioxidant, the titanium dioxide pigment described above) 50
Part by weight and 2.5 parts by weight of zinc stearate were thoroughly kneaded at 150° C. using a Banbury mixer to prepare a masterbatch of titanium dioxide pigment.

In addition, 50 parts by weight of the same low-density polyethylene as used in the preparation of the titanium dioxide pigment masterbatch, 50 parts by weight of the above titanium dioxide pigment, and 1°25 parts by weight of ultramarine blue (manufactured by Dai-Kasei Kogyo Co., Ltd., #2000). 15 parts by weight and 2.5 parts by weight of zinc stearate using a Banbury mixer.
Titanium dioxide pigment masterbatches containing ultramarine blue were prepared by kneading at 0°C.

Furthermore, the fluorescent agent [IX) described in the main text of the specification 0゜2
8 parts by weight of zinc stearate and 0.28 parts by weight of zinc stearate were thoroughly mixed in advance, and the mixture was mixed with the same low-density polyethylene 4 as used for preparing the titanium dioxide pigment masterbatch described above.
0 parts by weight were thoroughly kneaded at 135° C. using a Labo Plastomill to prepare a fluorescent agent masterbatch.

On the other hand, a mixed stock of 50 parts by weight of bleached hardwood kraft pulp and 50 parts by weight of bleached softwood rulphite pulp was beaten to Canadian φ standard φ freeness of 310 m1,
Further, per 100 parts by weight of pulp, 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 content), and 0.4 parts by weight of polyaminopolyamide epichlorohydrin resin. Adding parts by weight, basis weight 160g/rrf
paper was produced. The obtained wet paper was dried at 110°C, and then 3 parts by weight of carboxy-modified polyvinyl alcohol,
Impregnated with 25 g/rd of an impregnating solution consisting of 0.05 parts by weight of optical brightener, 0.002 parts by weight of blue dye, 0.2 parts by weight of citric acid, and 97 parts by weight of water, and dried with hot air at 110 ° C.
Further, after supercalendering at a linear pressure of 90 kg/country, both surfaces thereof were subjected to corona discharge treatment to produce a base paper for a resin-coated paper-type photographic support.

Next, apply high-density polyethylene (density 0°960) to the back side of the base paper.
g/cm3, MFR=5 g/10 minutes and low density polyethylene (density 0.'923 g/cm3, MFR
= 5g/10 min) was coated to a thickness of 30μ using a melt extrusion coater at a resin temperature of 330°C. Next, 18.8 parts by weight of the titanium dioxide pigment masterbatch described above, 7.2 parts by weight of a titanium dioxide pigment masterbatch containing ultramarine blue, 3.0 parts by weight of a fluorescent agent masterbatch, and a high-density diluent resin were then applied to the surface of the base paper. Polyethylene (density 0°970 g/cm3, MFR7.0 g/
l 0 min) and 20 parts by weight of low density polyethylene (density 0.
920g/cm3, MF R6, Oiz/10 minutes) 5
1 part by weight (54 parts by weight if no fluorescent agent masterbatch is added) at a resin temperature of 330°C.
Polyethylene resin-coated paper-type photographic supports of the present invention and outside the present invention were prepared by melt extrusion coating to a thickness of 0 μm. At that time, the surface of the polyethylene containing the titanium dioxide pigment was processed into a completely flat glossy surface, and the surface quality of the polyethylene on the back was processed into a paper-like matte surface.

The whiteness of the appearance of the titanium dioxide pigment-containing side of the polyethylene resin-coated paper-type photographic support thus obtained was visually evaluated. The evaluation criteria is very white→○
, white 10, slightly yellow → △, yellow → X.

In addition, die lip stain was measured as follows.

Using a screw extruder with an extrusion opening diameter of 65 mm and a melt extruder with a 750-width T-die, the melt temperature was 320°C.
After melt-extruding for 2 hours at a screw rotation speed of 1100 rpm, the number of stains generated on the grip was counted and measured.

Next, in order to measure the sharpness of printed images, color photographic paper having the above photographic support was produced. First, 0.4 g of a back coat layer consisting of a composition of colloidal silica: styrene acrylic latex - 1 = 1 was applied as a dry weight component to the back side of a photographic support after corona discharge treatment.
/rd coating was applied.

Then, after corona discharge treatment, a blue-sensitive emulsion layer containing a yellow color-forming coupler, an intermediate layer containing a color mixing preventive agent, a green-sensitive emulsion layer containing a magenta color-forming coupler, A color photographic paper was obtained by providing an ultraviolet absorbing layer containing an ultraviolet absorber, a red-sensitive emulsion layer containing a diazide coloring coupler, and a protective layer. Each color-sensitive emulsion layer was coated with silver nitrate at 0.
Contains silver chlorobromide equivalent to 6 g/rrr, and also contains gelatin necessary for silver halide production, dispersion, and film formation, as well as appropriate amounts of antifoggants, sensitizing dyes, coating aids, hardeners, and thickeners. Contains sticky agent and appropriate amount of filter dye.

A resolution chart was adhered to the resulting photographic paper, exposed to green light, and color developed to obtain a test sheet.

This test sheet was measured with a microdensitometer, and the sharpness of the image of the magenta layer was calculated using a personal computer according to a conventional method.
The sharpness of the printed image of the photographic support was determined by determining the contrast transfer function.
This shows that the sharpness of the printed image is high.

The results obtained are shown in Table 1.

(Margins below) As shown in Table 1, titanium dioxide pigment is contained in the resin layer of the resin-coated paper-type photographic support on the side where the image is formed, and its particle diameter was measured using an electron microscope in a directional manner. 0°110μm to 0.150μm expressed as number average diameter
The photographic support in the present invention (samples Nα12 to Nα17) containing a titanium dioxide pigment carrying a calcium compound on the particle surface and an antioxidant is:
It can be seen that this is an excellent photographic support with high sharpness of printed images, less occurrence of die lip stains during production of the photographic support, and therefore good surface quality. In particular, photographic supports containing titanium dioxide pigments with particle diameters of 0.115 μm to 0.135 μm in the resin layer (samples Nα13 to Nα16) have particularly high sharpness of printed images and are stained with die lip stains. It can be seen that the occurrence of is extremely small, making it particularly excellent. In addition, a photographic support containing a fluorescent agent in the resin layer of the photographic support (sample N
It can be seen that samples α12 to 14, N+116 to NQ17) are visually whiter and are particularly excellent photographic supports than the photographic support containing no fluorescent agent (sample Nα15).

On the other hand, photographic supports other than the present invention (samples Nα1 to Nα11
, Nα18 to Nα19) each have their own problems.

That is, photographic supports that do not contain antioxidants in their resin layers (samples Nα1 to Nα9) have a problem in that they often generate gripp stains; However, those containing titanium dioxide pigments with a particle size of less than 0°110 μm (samples Nα10 to Nα
α11) still has a lot of grip stains, on the other hand,
It can be seen that those containing titanium dioxide pigments with particle diameters larger than 0.150 μm (samples Nα18 to Nα19) have a problem in that the sharpness of the printed images is low.

Example 2 In Example 1, the titanium dioxide pigment in the resin of the resin-coated paper-type photographic support had a particle diameter of 0.124 μm, expressed as a number average diameter in directional measurement using an electron microscope, and Example 1 except that a titanium dioxide pigment is used which carries on its surface the amounts of calcium compounds listed in Table 2, calculated in the form of calcium per titanium dioxide.
It was carried out in the same manner as sample Nα14.

The results obtained are shown in Table 2.

(The following is a blank space) As can be seen from Table 2, as titanium dioxide pigment in the resin layer of a resin-coated paper-type photographic support, 0.004% by weight of calcium is added to the surface of the particles, calculated in the form of calcium per titanium dioxide. The photographic supports of the present invention (samples Nα23 to Nα27) containing titanium dioxide pigments carrying ~0.1% by weight of calcium compounds have high sharpness of printed images and are suitable for photographic supports. It can be seen that it is an excellent photographic support with little occurrence of gripp stains during production and good surface quality. On the other hand, a photographic material other than the present invention using a titanium dioxide pigment carrying on the particle surface an amount of calcium compound in an amount of less than 0.004% by weight or more than 0.1% by weight calculated in the form of calcium per titanium dioxide It can be seen that the supports (samples Nα2O-N122 and Nα28) have problems because the sharpness of the printed images is low and there is also a lot of gripp staining.

Example 3 As a low-density polyethylene resin for a masterbatch, tetrakis[methylene (3,5-di-1e-butyl- The test was conducted in the same manner as Sample Nα14 in Example 1, except that methane (4-hydroxy-hydrozinate) was mixed in the amount shown in Table 3 in advance.

The results obtained are shown in Table 3.

(Margin below) Table 3 (Note 6) The amount added is expressed as the amount (ppm) relative to the resin composition containing the titanium dioxide pigment.

(Note 7) Same meaning as Table 1.

As understood from Table 3, by incorporating an antioxidant into the resin layer of the resin-coated paper-type photographic support,
It can be seen that the occurrence of gui-lip stains is well prevented.

Its content is 10 to 110% of the resin composition.
It can be seen that a range of 00 ppm is preferable, and a range of 20 to 500 ppm is particularly preferable. The photographic support of the present invention containing an appropriate amount of antioxidant as described above is as follows:
It can be seen that this is an excellent photographic support with high sharpness of printed images, very little occurrence of gripp stains during production of the photographic support, and good surface quality.

Example 4 Instead of the titanium dioxide pigment used in Example 2, the particle size expressed as the number average particle size in directional measurement using an electron microscope was 0.124 μm, and various amounts of magnesium compounds were added to the particle surface. Alternatively, the same procedure as in Example 2 was carried out except that a titanium dioxide pigment supporting a barium compound was used.

At that time, the titanium dioxide pigment was produced in the same manner as in Example 1,
Mg was used instead of CaCl2 6H2° used in Example 1.
5O,'7H20 or B a C12.2H,O was used.

As a result, the same results as in Example 2 were obtained.

Example 5 Antioxidant used in Example 2 Tetrakis [methylene (3
, 5-terl-butyl-4-hydroxy-hydrocinnamate)] instead of methane, octadigital-3
,5-di-1ft-butyl-4-hydroxy-hydrocinnamate, 2,2',2'-tris((3,5-dite11-butyl-4-hydroxyphenyl)propionyloxy)ethyl isocyanurate or 1,3 ．．
5-1 Lis(4-feel-butyl-3-hydroxy-
The same procedure as in Example 3 was carried out except that 2,6-dimethylbenzyl)isocyanurate was used, and the same results as in Example 3 were obtained.

Example 6 Instead of the rutile titanium dioxide pigment used in Example 1,
The same procedure as in Example 1 was carried out except that the following anatase type titanium dioxide pigment was used.

Anatase produced under hydrolysis conditions and calcination conditions predetermined to obtain the particle size listed in Table 4 in accordance with the production process of anatase-type titanium dioxide pigment by the sulfuric acid method described in the main text of the specification. A type of titanium dioxide linker was crushed and sized, and further wet-pulverized and classified to obtain a titanium dioxide slurry substantially free of coarse titanium dioxide. This slurry was put into a reaction treatment tank, and the CaCl2
- Add a 10% by weight aqueous solution of 6H20. Thereafter, the surface was treated with hydrous aluminum oxide in the same manner as in Example 1, followed by washing, drying, and final pulverization to produce anatase titanium dioxide pigments with different particle sizes carrying calcium compounds on the particle surface. did.

The results obtained are shown in Table 4.

As shown in Table 4, titanium dioxide pigment is contained in the resin layer on the side where the image is formed of the resin-coated paper-type photographic support, and the particle size thereof is 0.110 μm to 0.150 μm, and The photographic support of the present invention (samples Nα42 to Nα43) containing a titanium dioxide pigment carrying a calcium compound on the particle surface and an antioxidant has high sharpness of printed images and is a photographic support. It can be seen that it is an excellent photographic support with little occurrence of gripp stains during production and therefore good surface quality.

On the other hand, photographic supports other than the present invention (samples Nα38 to Toru 41
, fish 44) each have their own problems.

That is, photographic supports that do not contain antioxidants in their resin layers (samples Nα38 to Nα40) have a problem in that they often generate grip stains; However, the one containing titanium dioxide pigment with a particle size of less than 0°110 μm (sample Nα41) still causes a lot of gripp stains and the sharpness of the printed image is low; .Those containing titanium dioxide pigments larger than 150 μm (sample Nα
It can be seen that No. 44) is problematic because the sharpness of the printed image is low.

〔Effect of the invention〕

According to the present invention, it is possible to provide an excellent resin-coated paper-type photographic support, which has high sharpness of printed images, extremely little generation of gripp stains during the production of the photographic support, and therefore good surface quality.

Claims (12)

[Claims] (1) In a resin-coated paper-type photographic support in which at least one side of paper, synthetic paper, or film substrate is coated with a polyolefin resin composition, the polyolefin resin composition is at least (A) The particle size expressed as the number average diameter is 0.110 μm to 0.15
A titanium dioxide pigment having a particle size of 0 μm and carrying on its particle surface 0.004% to 0.1% by weight of a magnesium compound, calcium compound, or barium compound calculated in the form of metal per titanium dioxide. A photographic support characterized by containing a titanium pigment and (B) an antioxidant. (2) The photographic support according to claim 1, wherein the titanium dioxide pigment has a rutile structure. (3) The photographic support according to claim 1 or 2, wherein the titanium dioxide pigment is pulverized using a fluid energy mill. (4) The photographic support according to claim 3, wherein the fluid energy mill is a steam mill. (5) The photographic support according to claim 1, 2, 3 or 4, wherein the antioxidant is a hindered phenolic antioxidant. (6) The content of the antioxidant is 10 ppm to 1000 ppm based on the polyolein resin composition.
Photographic support according to 2, 3, 4 or 5. (7) The photographic support according to claim 1, 2, 3, 4, 5 or 6, wherein the polyolefin resin is a polyethylene resin. (8) The photographic support according to claim 1, 2, 3, 4, 5, 6 or 7, wherein the polyolefin resin composition contains a higher fatty acid metal salt. (9) The photographic support according to claim 1, 2, 3, 4, 5, 6, 7 or 8, wherein the polyolefin resin composition contains a fluorescent agent. (10) The photographic support according to claim 9, wherein the fluorescent agent is a bis(benzoxazolyl)naphthalene fluorescent agent having a substituent or a bis(benzoxazolyl)stilbene fluorescent agent having a substituent. (11) Fluorescent agent content is 0.3mg/m^2~30m
The photographic support according to claim 9 or 10, which has a molecular weight of g/m^2. (12) Claim 1, wherein the content of titanium dioxide is 9% to 30% by weight based on the polyolefin resin composition.
2, 3, 4, 5, 6, 7, 8, 9, 10 or 11.