JP2714137B2 - Photographic support - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a resin-coated paper type photographic support in which at least one surface of a paper, a synthetic paper or a film substrate is coated with a polyolefin resin containing a titanium dioxide pigment. More specifically, the present invention relates to an excellent photographic support having a high sharpness of a printed image, a very small generation of die lip stains during the production of the photographic support, and hence a good surface quality.

(Prior art)

As a photographic support, at least one surface of the substrate is
A resin-coated paper type photographic support coated with a resin composition comprising at least a tan dioxide pigment and a polyolefin resin is well known. For example, U.S. Pat. No. 3,501,298 discloses a technique for a photographic support in which both sides of a paper substrate are coated with a polyolefin resin. Also, since the rapid photographic development process was applied, a photographic support in which both sides of a photographic paper base paper were coated with a polyethylene resin,
It is mainly used for photographic printing paper, and one of the resin layers on the image forming side usually contains a titanium dioxide pigment for imparting sharpness.

Conventionally, anatase type and rutile type titanium dioxide pigments are known as titanium dioxide pigments to be contained in a resin layer on the image forming side of a resin-coated paper type photographic support. Further, titanium dioxide particles whose surface 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, containing aluminum hydroxide, Titanium dioxide pigment coated with a hydrated metal oxide such as hydrous silicon oxide, and further disclosed in JP-A-52-35625 and JP-B-58-43734.
Titanium dioxide pigments whose surface is coated with an organic substance such as a polyhydric alcohol or a derivative thereof or a polyorganosiloxane or a derivative thereof as described or exemplified in JP-B-61-26552. Are known.

On the other hand, when a particularly high sharpness of a printed image is required as a photographic support, some resin-coated paper-type photographic supports are also known. For example, (1) a titanium dioxide pigment contained in a resin layer at a high concentration,
(2) a titanium dioxide pigment in the resin layer containing a rutile type pigment; (3) a metal such as zinc stearate, calcium stearate, zinc palmitate or the like as described in JP-B-58-43734. A resin layer containing a titanium dioxide pigment by adding a surfactant represented by soap. (4) As a titanium dioxide pigment in the resin layer, the particle surface is coated with the organic substance as described above. What contains a so-called organically treated titanium dioxide pigment is known.

However, these resin-coated paper-type photographic supports have insufficient sharpness and some other serious problems with respect to photographic aptitude and production aptitude, and are still unsatisfactory. The fact is that the desired results have not been obtained.

First, when the concentration of the titanium dioxide pigment in the resin layer of the polyolefin resin-coated paper-type photographic support is increased, a photographic support having a high sharpness of a printed image is obtained, Serious manufacturability problems often arise. That is, when a polyolefin resin composition containing a titanium dioxide pigment, particularly a polyethylene-based resin composition is melt-extruded and coated on a substrate from a slit die into a film, a short extrusion is used to form a needle at the tip of a die lip. Icicle-like attachments or stains (hereinafter simply referred to as die lip stains) tend to occur, and, worse, the die lip stains tend to grow steadily with the lapse of melt extrusion time.

If this die lip stain occurs during melt extrusion coating, streaks occur in the vertical direction on the surface of the polyolefin resin-coated paper produced as it is, or streak-like unevenness due to uneven coating amount occurs. Occasionally, and sometimes dirt adheres to the film and is applied, and foreign matter appears. For this reason, the surface quality of the polyolefin resin-coated paper is significantly impaired, and there has been a problem that it is completely unsuitable and has no commercial value as a photographic support requiring excellent surface quality. In addition, there is no other way to completely remove the die lip contamination that has occurred once the production is stopped and the die lip is cleaned or the die is replaced, and the cleaning or replacement requires a great deal of labor and time. There is a problem that productivity is remarkably reduced.

In the first place, as the titanium dioxide pigment in the resin layer of the polyolefin resin-coated paper-type photographic support, the surface of titanium dioxide particles is coated with a hydrated metal oxide such as hydrated aluminum oxide and hydrated silicon oxide due to strict requirements in terms of quality. Treated titanium dioxide pigments (hereinafter simply referred to as hydrated metal oxide-treated titanium dioxide pigments) are mainly used, and so-called untreated titanium dioxide pigments that have not been subjected to any surface treatment are often used. Not. However, when a hydrated metal oxide-treated titanium dioxide pigment is used, the higher the treatment with a hydrated metal oxide, the more noticeable the occurrence of dilip stains. On the other hand, when an untreated titanium dioxide pigment is used, the occurrence of die lip stains is small, but the light deterioration of the resin layer is remarkable, and the resin layer is liable to discolor with time.

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

Secondly, when a rutile-type titanium dioxide pigment is used as the titanium dioxide pigment to be contained in the resin layer of the polyolefin resin-coated paper-type photographic support, the printing is smaller than when an anatase-type pigment is used. Although photographic supports with significantly higher image sharpness can be obtained, another serious problem with photographic adequacy arises. That is, the resin surface containing the titanium dioxide pigment on the image forming side of the photographic support has a yellow tint due to the rutile type titanium dioxide pigment, and a photographic support having a clear whiteness cannot be obtained. There was a problem that a print on a white background could not be obtained.

Third, as a result of investigations by the present inventors, when a titanium dioxide pigment is contained in a resin layer of a polyolefin resin-coated paper-type photographic support, a metal soap such as zinc stearate, calcium stearate, and zinc palmitate is used. It has been found that there is a problem that the sharpness of the printed image of the photographic support is not substantially high even when a surfactant represented by the formula (1) is added.

Generally, as a method of incorporating a titanium dioxide pigment into a resin layer of a polyolefin resin-coated paper-type photographic support, a conventional melt kneader such as a Banbury mixer, a kneader, or a kneading extruder is used. A so-called masterbatch, which is contained in a high concentration, is prepared and melt-extrusion coated with a polyolefin resin composition diluted and mixed in a desired ratio with a diluting resin, or a pigment is added to the resin in a desired manner from the beginning. Usually, a so-called compound containing only the composition ratio is prepared and subjected to melt extrusion coating. The main purpose of the metal soap originally added to the resin layer of the polyolefin resin-coated paper-type photographic support is that when the photographic support is produced by melt extrusion coating, a cooling roll of a melt extruder is used. To improve the releasability between the resin and the resin-coated surface.

However, as a result of the study by the present inventors, completely new knowledge has been found regarding the effect of the metal soap in the resin layer.
That is, as a concentration in the resin layer of the polyolefin resin-coated paper-type photographic support of the metal soap added when preparing the master batch or the compound of the titanium dioxide pigment, 1.5% by weight based on the titanium dioxide pigment, and Up to 0.15% by weight of the composition, the sharpness of the printed image of the photographic support increases, but at this content, the releasability is poor, and 1.5% to 7.5% by weight of the titanium dioxide pigment. When the content is in the range of 0.15% by weight to 0.75% by weight with respect to the resin composition, the releasability is improved with the added amount, but the sharpness of the printed image of the photographic support is reduced. It turned out to be considerably lower, and sometimes lower than without metal soap.

Further, when the content is more than that, the sharpness of the printed image of the photographic support gradually decreases with the addition amount, so that the generation of oily smoke increases, and the production suitability at the time of melt extrusion coating becomes extremely high. It turned out to be worse. As described above, even when a metal soap is added when a titanium dioxide pigment is added to the resin layer of the polyolefin resin-coated paper-type photographic support, a photographic support having high sharpness of a printed image cannot be obtained. There was a problem.

Fourth, as a result of investigations by the present inventors, as a titanium dioxide pigment to be contained in a resin layer of a polyolefin resin-coated paper type photographic support, a so-called organically treated titanium dioxide pigment can be used. The inventor has the problem that the sharpness of the printed image of the body is not substantially high at all. That is, a metal soap typified by zinc stearate or the like together with an organically treated titanium dioxide pigment in a resin layer of a polyolefin resin-coated paper-type photographic support, up to an amount such that sufficient release properties are exhibited during the production of the photographic support. When added, the sharpness of the printed image of the photographic support was found to have a problem that it was almost the same or slightly higher than when a titanium dioxide pigment not subjected to organic treatment was used. .

[Problems to be solved by the invention]

Accordingly, an object of the present invention is to produce a photographic support in which at least one surface of a paper, a synthetic paper or a film substrate is coated with a polyolefin resin composition containing a titanium dioxide pigment, which has a high sharpness of a photographic print image. It is an object of the present invention to provide an excellent photographic support which sometimes produces very little die lip stain and therefore has good surface quality.

[Means and actions for solving the problems]

In order to solve the above-mentioned problems, the present inventors have conducted intensive studies and found that a paper, synthetic paper or a resin-coated paper-type photographic support in which at least one surface of a film substrate was coated with a polyolefin resin composition. The polyolefin resin composition has at least (A) a particle diameter of 0.110 μm to 0.150 μm expressed as a number average diameter in a unidirectional measurement by an electron microscope.
And a titanium dioxide pigment carrying 0.004% by weight to 0.1% by weight of a magnesium compound, a calcium compound or a barium compound, calculated on the surface of the particles in the form of metal per titanium dioxide,
In addition, the surface of the particles contains at least aluminum atoms in an amount of more than 0.2% by weight and less than 1.8% by weight calculated in the form of anhydrous metal oxide per titanium dioxide, and 0.4% by weight or less (0 It has been found that the object of the present invention can be achieved by a photographic support containing a titanium dioxide pigment treated with a hydrated metal oxide of the present invention and (B) an antioxidant.

Further, the present invention can advantageously provide a more preferable resin-coated paper type photographic support. That is, as a result of the study by the present inventors, at least one surface of paper, synthetic paper or a film substrate is coated with a polyolefin resin composition, and the resin layer on the side containing the titanium dioxide pigment of the resin-coated paper-type photographic support is provided. In order to improve the whiteness of the polyolefin resin composition, a titanium dioxide pigment, particularly a titanium dioxide pigment treated with a hydrated metal oxide and a fluorescent agent, in particular, for example,
Resin-coated paper type photographic support containing a bis (benzoxazolyl) naphthalene-based fluorescent agent as described in US Pat. No. 51336 or a bis (benzoxazolyl) stilbene-based fluorescent agent as described in US Pat. No. 4,794,071 When the body is manufactured, the generation of die lip stains is promoted, and further, when the resin composition contains an inorganic or organic coloring pigment or coloring dye, particularly, an inorganic coloring pigment, the occurrence of die lip staining is further promoted. It turned out that there was. However, according to the present invention, (A) the specific titanium dioxide pigment of the present invention and (B)
Antioxidants and further (C) fluorescent agents, especially bis (benzoxazolyl) naphthalene-based fluorescent agents or bis (benzoxazolyl) stilbene-based fluorescent agents and / or (D) coloring pigments or coloring dyes, especially inorganic colorings In the production of a photographic support in which the resin composition is coated on a substrate even if a pigment is contained, the occurrence of die lip stain is extremely low, and therefore the surface quality is good, the sharpness of the printed image is high, and the brightness is high. It has been found that it is possible to provide a more excellent resin-coated paper-type photographic support which is high in appearance and white in appearance, and has good whiteness stability.

The titanium dioxide pigment used in the practice of the present invention has a particle diameter of 0.110 μm to 0.150 μm expressed as a number average diameter in a directional measurement by an electron microscope, and the surface of the particle has a particle diameter of metal per titanium dioxide. 0.00
4% to 0.1% by weight of a magnesium compound, a calcium compound or a barium compound supporting rutile structure, anatase structure, a mixed crystal of rutile and anatase structures or a mixture thereof, Further, any of those prepared by a sulfuric acid method or a chlorine method can be used, but a rutile structure is preferable in order to obtain a photographic support having particularly high sharpness of a printed image. It should be noted that the rutile structure titanium dioxide referred to in this specification (hereinafter simply referred to as rutile type titanium dioxide).
The term "having a crystal structure" means that 90% by weight or more, preferably 95% by weight or more has a rutile structure. In addition, the number average diameter in the directional measurement by an electron microscope referred to in this specification is a value obtained by averaging the length of titanium dioxide pigment particles obtained by directional measurement with an electron microscope for 1,000 particles, It is displayed in μm.

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

Raw ore → digestion / extraction → standing / crystallization → filtration / concentration → hydrolysis → washing → firing → grinding / rectification → wet grinding / classification → surface treatment → washing / drying → finish grinding → titanium dioxide pigment. In the case of the sulfuric acid method, iron sulfate is usually separated from the solution obtained by treating ilmenite with sulfuric acid, and hydrolyzed titanium oxide is formed by hydrolysis of the separated titanyl sulfate aqueous solution.
It is fired to develop its pigmentary properties. The hydrolysis of the aqueous solution of titanyl sulfate is carried out by adding a titanyl sulfate solution to warm water and depositing hydrous titanium oxide to form a seed, or a so-called self-seeding method, or a method of neutralizing titanium titanyl sulfate or titanium tetrachloride. This can be performed by a so-called external seed method in which an oxide is added as a seed.
In addition, when producing a rutile structure,
The sintering is performed at a temperature of 800 to 1100 ° C. by raising the sintering temperature to a higher temperature than in the case of producing an anatase structure, or by coexisting a metal compound such as sodium, potassium, and zinc to promote the formation of a rutile structure during sintering. .

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

High purity ore or synthetic rutile → chlorination → separation / condensation →
Refining → Preheating → Firing decomposition → Separation → Pulverization and sizing → Wet pulverization ・
Classification → Surface treatment → Washing / drying → Finish pulverization → Titanium dioxide pigment.

The product produced by calcination or gas phase calcination will be referred to hereinafter as titanium dioxide clinker. Titanium dioxide clinker is dry-pulverized by 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 further subjected to a dry ball mill or a vibrating mill to wet pulverization. The wet classification is performed using a continuous horizontal centrifuge or / and through a vibrating double deck screen (325 mesh US standard screen), which is hereinafter referred to as fines. A titanium dioxide slurry free of coarse titanium dioxide is formed. When treating the surface of titanium dioxide particles with a hydrated metal oxide,
For fines in which the coarse particles have been removed and are still in the form of a slurry, the surface of the titanium dioxide particles is usually treated with a hydrated metal oxide containing at least aluminum atoms. After the surface treatment, the mixture is filtered and washed with a filter press, and then finely pulverized by an impact pulverizer and / or a fluid energy mill to produce a titanium dioxide pigment.

The titanium dioxide pigment used in the practice of the present invention has a particle diameter in the range of 0.110 μm to 0.150 μm expressed as a number average diameter measured in a directional direction by an electron microscope.
A photographic support coated with a polyolefin resin composition containing a titanium dioxide pigment having an average individual diameter of less than 110 μm has a problem in that the production of die lip stains often occurs and the sharpness of a printed image is low. On the other hand, 0.
A photographic support coated with a polyolefin resin composition containing a titanium dioxide pigment having a number average diameter of more than 150 μm has a problem that the sharpness of a printed image is considerably lowered. As the titanium dioxide pigment used in the practice of the present invention, the occurrence of die lip stain during the production of a photographic support is extremely low, and the sharpness of the printed image is high, and its number average diameter is 0.115 μm to 0.135 μm. Are preferred. Number average diameter is 0.110μm ~ 0.150μm
Can be obtained by manufacturing under the predetermined manufacturing conditions. The production conditions of the titanium dioxide pigment, in particular, the calcination temperature, the calcination time, and the inorganic compound to be present during the calcination, for example, JP-B-48-18718.
The calcination conditions such as the type and abundance of the inorganic compounds and their combined compounds described or exemplified in the above item are the number average diameters of the titanium dioxide pigments manufactured under a series of combination experiment conditions, as measured by directional measurement with an electron microscope. It can be determined by measuring. 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 calculated in the form of an inorganic oxide. In particular, combination conditions in the range of 0.2 to 5% by weight per titanium dioxide are particularly preferred.

The titanium dioxide pigment used in the practice of the present invention has a particle surface of 0.004 calculated in the form of metal per titanium dioxide.
It is manufactured by supporting at least one compound selected from a magnesium compound, a calcium compound and a barium compound in an amount of from 0.1% 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, the photographic support coated with the polyolefin resin composition containing the titanium dioxide pigment will have a large amount of die lip stains during its production, and the sharpness of the printed image will be poor. The problem is getting lower. On the other hand, when the loading amount is more than 0.1% by weight, the photographic support coated with the polyolefin resin composition containing the titanium dioxide pigment also tends to cause dilip stains during its production, and the sharpness of the printed image Is a problem. A preferred range of the supported amount is 0.006% by weight to 0.07% by weight calculated in the form of a metal based on titanium dioxide.
Range. 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 a hydroxide. Specific examples thereof include calcium chloride, magnesium chloride, magnesium sulfate, barium chloride, calcium hydroxide, calcium oxide, magnesium hydroxide, magnesium oxide, barium hydroxide, barium oxide, calcium acetate, magnesium acetate, calcium citrate, Examples include magnesium citrate, calcium carbonate, magnesium carbonate and the like.

Further, as a method of supporting a calcium compound, a magnesium compound or a barium compound on the surface of titanium dioxide particles, in the production process of a titanium dioxide pigment,
The process is carried out by allowing these compounds to coexist in a titanium dioxide slurry at any stage after the process of suspending the ground titanium dioxide clinker in water to form a titanium dioxide slurry. Preferably, it is carried out by adding an aqueous solution or suspension of these compounds to the titanium dioxide slurry at an arbitrary stage after the wet pulverization / classification step to make them coexist, and thus to adsorb them on the surface of the titanium dioxide particles.

In addition, as a result of investigations by the present inventors, the amount of magnesium compound, calcium compound or barium compound supported on the surface of titanium dioxide particles depends on the type and amount of those compounds, the particle diameter of titanium dioxide, the specific surface area, and the crystal form. Properties and conditions of titanium dioxide particles such as crystal structure, type and amount of surface treatment with hydrated metal oxides, slurry conditions such as pH, temperature, concentration of titanium dioxide slurry, addition conditions of addition stage, etc. It became clear that it was determined by various factors or conditions. Therefore, the specific production conditions, especially the type and amount of magnesium compound, calcium compound or barium compound, are determined for titanium dioxide pigments produced under a series of combined experimental conditions by including the pigments in a polyolefin resin layer. While the performance of the obtained polyolefin resin-coated paper-type photographic support is examined, the amount of these compounds carried on the surface of the pigment is determined analytically to be determined. The amount of these compounds carried on the surface of the titanium dioxide particles is usually much lower than the amount added to the titanium dioxide slurry. The amount of the magnesium compound, calcium compound or barium compound carried on the surface of the titanium dioxide particles in the present specification is specifically determined analytically by the following method.

1.000 g of the sample titanium dioxide pigment is precisely weighed and put into a crucible, and 10 ml of a special grade 36% by weight hydrochloric acid solution is added.
Cover the crucible and heat on a sand bath at 360 ° C ± 20 ° C for 15 minutes, cool and filter (if filtration is incomplete, also use centrifugation). Thereafter, 10 ml of a special grade 36% by weight hydrochloric acid solution was washed with 10 ml of dilute hydrochloric acid diluted with 490 ml of distilled water, and 3% by weight of special grade SrCl ₂ was added to the obtained filtrate.
・ 3 ml of 6H ₂ O distilled water is added, and the total amount is adjusted to 100 ml with distilled water to obtain a test solution. The test solution is measured by an atomic absorption method, and the concentration of calcium, magnesium or barium in the test solution is obtained from a calibration curve obtained in advance, and thus the amount of the compound supported on the particle surface of the titanium dioxide pigment is determined. .

As the titanium dioxide pigment used in the practice of the present invention, those whose particle surfaces are surface-treated with a specific amount of a hydrated metal oxide containing at least aluminum atoms, or whose particles are internally treated with at least a specific amount of an aluminum compound, are used. May be advantageously used, or may be subjected to a combined treatment of a surface treatment and an internal treatment. Further, in the case where the internal treatment has been performed, the surface treatment may not be performed. In particular, in the case of the sulfuric acid method, it is useful from the viewpoint of designing a titanium dioxide pigment that the surface of the particle is treated with a specific amount of a hydrated metal oxide containing at least an aluminum atom.

Titanium dioxide pigment which is advantageously used in the practice of the present invention, which has been surface-treated with a hydrated metal oxide, has a particle surface after wet pulverization and classification of titanium dioxide of 0.2% in the form of anhydrous metal oxide per titanium dioxide. More than 1.8% by weight
Containing a lower amount of at least aluminum atoms,
As the silicon dioxide component, those treated with a hydrous metal oxide of 0.4% by weight or less (including 0) are useful. If the treatment amount of the titanium dioxide surface is 0.2% by weight or less, there is a problem that the weather resistance of the resin layer of the resin-coated paper type photographic support containing the titanium dioxide pigment is deteriorated. On the other hand, the processing amount is 1.8
If the content is more than 10% by weight, the generation of dilip stains becomes remarkable, which is a problem. A preferable range of the treatment amount is from 0.35% by weight to 1.5% by weight of anhydrous metal oxide with respect to titanium dioxide.
% By weight, particularly preferably in the range from 0.5% to 1.0% by weight. As a hydrous metal oxide containing not less than 0.4% by weight (including 0) of silicon dioxide containing at least aluminum atoms, it is preferable that the surface treatment is carried out with hydrous aluminum hydroxide. %, Preferably less than 0.2% by weight of hydrous silicon oxide, or other hydrous metal oxides such as hydrous titanium oxide in a total amount of less than 1.8% by weight of anhydrous metal oxide, or carbon dioxide. Can be surface-treated with less than 0.4% by weight of hydrous silicon aluminum oxide atoms.

As a method of treating the surface of the titanium dioxide particles with a hydrated metal oxide, the pH of the titanium dioxide slurry is adjusted to 5 or more, preferably 6 or more, particularly preferably around 7 after wet grinding and classification, and then the titanium dioxide slurry is treated with titanium dioxide. Add a water-soluble aluminum salt and, if necessary, other water-soluble metal salts and water-soluble silicon compounds to the slurry, and then continuously change the pH in the slurry to obtain a sparingly soluble aluminum hydroxide and, if necessary, other poorly soluble aluminum hydroxide. Oxide hydrate can be precipitated on titanium dioxide pigment and surface treated. For example, to describe a typical method in the case of performing a surface treatment in a reaction treatment tank with a stirrer, a titanium dioxide slurry after wet pulverization and classification is added with a water-soluble alkali solution such as caustic soda and potassium hydroxide, Adjust the pH of the slurry to 7.0 ± 1.0. To a pH adjusted titanium dioxide slurry, add an aluminate such as alkali aluminate, and further, if necessary, an aqueous solution of a water-soluble alkali such as caustic soda and potassium hydroxide, and then reduce the pH to a slurry exhibiting alkalinity, In addition, in order to precipitate the hydrous aluminum oxide on the surface of the titanium dioxide particles, a surface treatment is performed 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 in a range of 7.0 ± 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. As inorganic surface treatment agents other than aluminates used for these surface treatments, as silicon compounds,
As titanium compounds such as alkali silicate and silicon tetrachloride,
In addition to titanium tetrachloride and the like, various compounds such as metal compounds such as zirconium, zinc and manganese, and phosphate compounds can be used.

In the case of the titanium dioxide pigment which is advantageously used in the practice of the present invention, which is internally treated with an aluminum compound, the inside of the particle is calculated in the form of Al ₂ O ₃ per titanium dioxide.
Those internally treated with at least an aluminum compound in an amount of more than 0.2% and less than 1.8% by weight are useful. If the processing amount inside the titanium dioxide is 0.2% by weight or less, there is a problem that the weather resistance of the resin layer of the resin-coated paper type photographic support containing the titanium dioxide pigment is deteriorated. on the other hand,
If the processing amount is 1.8% by weight or more, the occurrence of die lip stains increases, which is a problem. The preferred range of throughput, range to 0.35 to 1.5% calculated in the form of Al ₂ O ₃ relative to titanium dioxide. As the aluminum compound used for the internal treatment of the titanium dioxide particles, in the case of the sulfuric acid method, for example, aluminum chloride and aluminum sulfate which are aluminum compounds such as aluminum chloride, aluminum sulfate, aluminum hydroxide and sodium aluminate are preferable. In the case of the chlorine method, aluminum chloride is preferred. Further, as a method of treating the inside of the titanium dioxide particles with an aluminum compound, in the case of the sulfuric acid method, the method is performed by adding an aluminum compound before the calcination step. Titanium hydroxide concentrated in a mixer or the like is placed in a mixer, for example, a kneader, and the aluminum compound is added and mixed well, or redispersed in water in a mixing tank equipped with a stirrer, and the aluminum compound is added and mixed well. After that, it is made through a firing process. In the case of the chlorine method,
For example, it is made using an apparatus as disclosed in U.S. Pat. No. 3,121,641 to supply an aluminum compound, preferably aluminum chloride, simultaneously with titanium tetrachloride and oxygen during the calcining decomposition process.

The titanium dioxide pigment used in the practice of the present invention may be used after the surface treatment in order to further enhance the sharpness of the printed image of the resin-coated paper-type photographic support containing the pigment in the resin layer, or the surface is treated only by the internal treatment. Untreated ones are manufactured by supporting the calcium compound, magnesium compound or barium compound after wet grinding and classification, and then washing with water until the suspension electric conductivity described below is 60 μ / cm or less. Is preferred. Here, the suspension electric conductivity of the titanium dioxide pigment 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 heated to a temperature of 21.5 ° C. ± 0.5 with a magnetic stirrer by a stirring force of a rotor (rotation speed; 420 rpm / min). The mixture was stirred for 16 minutes while maintaining the temperature at ° C to form a titanium dioxide pigment suspension. Sixteen minutes after the start of stirring, the electric conductivity of the titanium dioxide pigment suspension was set to 21.5 ° C. ± 0.2.
The suspension is measured with stirring at 5 ° C. by means of an electric conductivity meter. The electrical conductivity thus obtained is defined as the suspension electrical conductivity of the titanium dioxide pigment referred to herein.

The suspension electrical conductivity advantageously used in the practice of the present invention is
Titanium dioxide pigment of 60μ / cm or less, after surface treatment, or those with no surface treatment only internal treatment after wet grinding and classification after supporting calcium compound, magnesium compound or barium compound, first filter press The mother liquor is filtered and subsequently produced by washing the titanium dioxide cake in a filter press with running water until a titanium dioxide pigment having a suspension electrical conductivity of 60 μ / cm or less is obtained. The washing conditions such as washing time, amount of used water, and used water pressure are as follows: the titanium dioxide cake collected under a series of combined experimental conditions is subjected to a subsequent treatment of drying and pulverization to form a titanium dioxide pigment, and the titanium dioxide pigment is suspended. It can be determined by measuring the suspension electrical conductivity. The water washing may be carried out with the slurry containing the titanium dioxide as it is, or by re-suspending the filter cake in the tank, and using flowing water in such a manner as to replace the accumulated water or the supernatant, together with the water washing in the filter press, or It can be done separately. Further, from the viewpoint of further increasing the sharpness of the printed image of the photographic support, the titanium dioxide pigment used in the practice of the present invention preferably has a suspension electric conductivity of 55 μ / cm or less, particularly 50 μ / cm. The following are more preferred.

The titanium dioxide pigment used in the practice of the present invention is obtained by washing the titanium dioxide cake with water and drying it in that the sharpness of the printed image of the resin-coated paper-type photographic support containing the pigment in the resin layer is further increased. It is advantageous to produce by pulverization with a fluid energy mill. As the liquid energy mill, a steam mill such as a micronizer is particularly preferable, but an air mill can be used in combination. In addition, it is particularly preferable that the first stage pulverization is performed by an impact pulverizer such as a hammer mill before the pulverization is performed by the fluid energy mill before the pulverization is performed by the fluid energy mill.

The titanium dioxide pigment used in the practice of the present invention may, of course, be subjected to various organic treatments with triethanolamine, trimethylolpropane, a metal salt of a resin acid, an organopolysiloxane, or the like, if necessary.

As the antioxidant used in the practice of the present invention, a resin-coated paper-type photographic support that does not interfere with the resin composition constituting the resin layer on the side on which an image is formed on the photographic support is acceptable. Phenol-based, amine-based or phosphate ester-based antioxidants can be used, but hindered phenol-based compounds are particularly preferred since they do not adversely affect the photographic emulsion layer and can more effectively prevent die lip stains. Antioxidants are preferred. Examples of the hindered phenol-based antioxidants that are advantageously used include, for example, 1,3,5-trimethyl-2,4,6-tris (3,5-di-ter
t-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-O-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), 4,4'-butylidenebis- (3-
Methyl-6-tert-butylphenol), 2,6-di-ter
t-butyl-4-methylphenol, 4-hydroxy
Methyl-2,6-di-tert-butylphenol, 2,6-di-
tert-4-n-butylphenol and the like.
Further, two or more antioxidants may be used in combination depending on the characteristics of the antioxidant.

The content of the antioxidant in the polyolefin resin composition is preferably 10% by weight in the resin composition.
It is in the range of 1000 to 1000 ppm, particularly preferably in the range of 20 to 500 ppm. Even if the amount of antioxidant is less than 5 ppm,
If it is more than 00 ppm, die lip stain tends to occur, and if it is more than 1000 ppm, the adhesion between the base paper and the resin layer tends to be poor. As a method for incorporating an antioxidant in the resin composition, a so-called compound in which an antioxidant is previously contained in a polyolefin resin to be used may be used, or the antioxidant may be contained at a relatively high concentration. May be used in an appropriate amount, or an antioxidant may be added when the resin composition is produced by a kneader. Further, depending on the type and content of the antioxidant used, the above methods may be appropriately combined.

Polyolefin resins used in the practice of the present invention include homopolymers such as polyethylene, polypropylene, polybutene and polypentene, and copolymers comprising two or more α-olefins such as ethylene-propylene copolymers and ethylene-butylene copolymers. Although they are coalesced and mixtures thereof, polyethylene resins are particularly preferred from the viewpoint of melt extrusion coating properties and economy. Examples of such polyethylene resins include low-density polyethylene, medium-density polyethylene, high-density polyethylene, linear low-density polyethylene, ethylene and propylene, copolymers of α-olefins such as butylene, carboxy-modified polyethylene, and the like. a mixture in any density of, (hereinafter referred to simply MFR) the melt flow rate, molecular weight, can be used those having a molecular weight distribution, typically, density of 0.90g / cm ³ ~0.97g / cm ³ range, MFR1g / 10 Min ~ 30g / 10min, preferably MFR3g / 10min ~ 15
Those having a g / min and a molecular weight in the range of 20,000 to 250,000 can be advantageously used alone or as a mixture. Further, when the resin has a multilayer structure, as the resin of the outermost layer, for example, one having an MFR of 5 to 20 g / 10 minutes, and as the resin of the lower layer, for example, one having an MFR of 2 to 10 g / 10 minutes. Can also be used.

As a method of 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, a so-called masterbatch in which the titanium dioxide pigment is previously contained at a certain concentration in the polyolefin resin is prepared. Then, a resin composition obtained by diluting and mixing them at a desired ratio with a diluting resin is used, or a so-called compound in which a titanium dioxide pigment is initially contained in a polyolefin resin in a desired composition ratio is prepared and used. Is normal. Usually, a Banbury mixer, a kneader, a kneading extruder, a two-roll kneading machine, a three-roll kneading machine, and the like are used for preparing these master batches and compounds, but a Banbury mixer and a kneading extruder are advantageously used. Can be
These kneaders may be used in combination of two or more.

Further, in order to improve the releasability of the resin-coated paper-type photographic support of the present invention during production, a fatty acid metal salt is added at the time of preparing a masterbatch or compound of titanium dioxide pigment, It is preferable to include a fatty acid metal salt 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, sodium laurate and the like. The addition amount is preferably in the range of 0.1% by weight to 50% by weight with respect to the titanium dioxide pigment, and in the range of 0.01% by weight to 5% by weight with respect to the resin layer containing the titanium dioxide pigment.

If the content of the 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, the sharpness of the printed image as the photographic support is reduced. Insufficient, on the other hand, 35% by weight
In the case described above, the fluidity is reduced and the extrusion characteristics are deteriorated, and the occurrence of stains on the die lip becomes remarkable, which is not preferred. Particularly preferred is the range of 9% by weight to 30% by weight. In the resin layer of the resin-coated paper-type photographic support of the present invention, the yellow tint caused by the titanium dioxide pigment, particularly the titanium dioxide pigment contained in the resin layer at a high concentration in order to obtain high sharpness, is improved. It is preferable to include a fluorescent agent in order to make the whiteness excellent. As such fluorescent agents, various fluorescent agents such as naphthalene-based, stilbene-based, thiophene-based, and coumarin-based fluorescent agents can be used, but the effect of improving whiteness, dispersibility of the fluorescent agent in polyolefin resin, heat resistance, Bis (benzoxazolyl) naphthalene-based fluorescent agents and / or bis (benzoxazolyl) stilbene-based fluorescent agents having a substituent are preferred from the viewpoints of bleed-out property, weather resistance, and stability in a photographic processing solution. preferable. Specific examples of the naphthalene-based fluorescent agent and the stilbene-based fluorescent agent that are advantageously used include those represented by the following formulas. In the case of a naphthalene-based fluorescent agent, the carbon number is C ₆ from the viewpoint of bleed-out resistance.
Those having the above substituents are preferred.

In addition, as a method for incorporating these fluorescent agents into the polyolefin resin composition, when a master batch or a compound of titanium dioxide pigment is produced, the fluorescent agent is added to the titanium dioxide pigment, the fluorescent agent, the polyolefin resin, and the fatty acid. A masterbatch or compound comprising a dispersant such as a metal salt can be prepared and included in the resin composition.

Further, it has a softening point lower than that of the main polyolefin resin and is a low-molecular-weight polyolefin which is solid at ordinary temperature or / and
A fluorescent agent masterbatch in which a fluorescent agent premixed with a dispersant, for example, a fatty acid metal salt, is dispersed in a main polyolefin resin can be prepared and included in the resin composition. The content of the photographic support of the resin layer of the fluorescent agent, whiteness, processability of the resin, from a comprehensive viewpoint, such as resistance to bleedout resistance, of 0.3mg / m ² ~30mg / m ² It ranges, particularly preferably in the range of ^{0.5mg / m 2 ~10mg / m 2} .

It is preferable that the resin layer of the resin-coated paper-type photographic support in the present invention contains an inorganic or organic blue pigment or blue dye to make the whiteness of appearance even more white. Specific examples thereof include cobalt blue, navy blue and ultramarine blue as inorganic compounds, and cerulean blue, phthalocyanine blue, and chromophthal blue A3R as organic compounds. In addition, as an addition amount, in the case of an inorganic blue pigment, 0.025% by weight to 0.5% by weight, preferably 0.05% by weight with respect to the resin layer.
To 0.2% by weight, and in the case of an organic blue compound, 0.001% to 0.1% by weight, preferably 0.0025% by weight.
0.050.05% by weight. If the amount is too small, the coloring effect is not obtained. If the amount is too large, not only the brightness is lowered but also the generation of die lip stains is undesirably increased.

Further, it is advantageous that the resin layer of the resin-coated paper type photographic support of the present invention contains an inorganic or organic magenta pigment or magenta dye as required. Specific examples thereof are cobalt violet,
Examples include fast violet, manganese purple, reddish ultramarine, and quinacridone red. The amount of these additives is 0.025% by weight to 1.0% by weight, preferably 0.1% by weight to 0.4% by weight in the case of an inorganic magenta pigment, and 0.0% by weight in the case of an organic magenta compound.
01% to 0.03% by weight, preferably 0.002% to 0.015%
% By weight.

The resin-coated paper-type photographic support of the present invention contains the titanium dioxide pigment and the antioxidant of the present invention, and more preferably contains the above-mentioned fatty acid metal salt, fluorescent agent, inorganic or organic coloring pigment or coloring dye. Although the resin layer has a stiffened resin layer, when the resin layer has a multilayer structure, the above-mentioned titanium dioxide pigment, an antioxidant, a fatty acid metal salt, and a fluorescent agent are also used for the resin layers other than the resin layer in the present invention. , A coloring pigment or a coloring dye. Further, in the resin layer on the image forming side of the photographic support in the present invention and the resin layer on the opposite side, the above titanium dioxide pigment, antioxidant, fatty acid metal salt, fluorescent agent, coloring pigment or coloring In addition to dyes, white pigments such as titanium dioxide, zinc oxide, talc, calcium carbonate, etc., fatty acid amides such as stearamide, arachidic amide, organic silicone compounds such as polyorganosiloxane, tinuvin 320, tinuvin 326, Tinuvin 328
It is preferable to add various additives such as ultraviolet absorbers (as mentioned above, trade names of Ciba-Geigy Co., Ltd.) in an appropriate combination.

The photographic support manufactured according to the present invention is manufactured by a so-called extrusion coating method in which a heated and melted polyolefin resin is cast on a running substrate paper, synthetic paper or film, and both surfaces are usually coated with the resin. . At that time, in the case of a multilayer structure, a plurality of resin layers of the photographic support are sequentially, preferably continuously, extrusion-coated, so-called tandem extrusion coating system or a plurality of resin layers are simultaneously multilayer-extruded, It is preferred to use a so-called co-extrusion coating system. Further, it is preferable to perform an activation treatment such as a corona discharge treatment or a flame treatment on the substrate before coating the resin on the substrate. The emulsion-side surface of the photographic support has a glossy surface or a finely rough surface or matte surface or matte surface described in JP-A-55-26507, which does not affect the gloss of the surface of the photographic paper when photographic paper is used. The back surface is usually a matte surface, and an activation treatment such as a corona discharge treatment or a fire treatment can be applied to the front surface or both the front and back surfaces if necessary. Further, after the activation treatment, JP-A-61-8464
Subtraction processing as described in No. 3 can be performed.

The thickness of the resin layers on the front and back sides of the resin-coated paper-type photographic support is not particularly limited, but generally, extrusion-coated to a thickness of about 10 μm to 50 μm is advantageous.

Examples of the substrate used in the practice of the present invention include natural pulp paper mainly composed of ordinary natural pulp, mixed paper made of natural pulp and synthetic fiber, synthetic fiber paper mainly composed of synthetic fiber, polystyrene, polypropylene and the like. Any of so-called synthetic paper obtained by converting the synthetic resin film into pseudo paper or a film such as cellulose acetate, polyethylene terephthalate, and polycarbonate may be used. However, as a substrate of a photographic printing paper support, the effect of the present invention, that is, sharpness of a printed image, Natural pulp paper (hereinafter simply referred to as "atom") is particularly preferred because it is highly economical, has no die lip streaks, and therefore can provide an excellent photographic support with good surface quality economically. It is advantageously used.

Examples of the pulp constituting the atoms preferably used in the practice of the present invention include JP-A-58-37642 and JP-A-60-67940.
It is advantageous to use an appropriately selected natural pulp as described or exemplified in JP-A-60-69649, JP-A-61-35442, etc. Synthetic pulp or synthetic fiber may be used. Natural pulp is chlorine, hypochlorite, chlorine bleach normal bleaching treatment and alkali extraction or alkali treatment and, if necessary, hydrogen peroxide, oxidative bleaching treatment with oxygen, etc.
And softwood pulp treated in combination with them,
Wood pulp of hardwood pulp and softwood hardwood mixed pulp is advantageously used, and various types such as kraft pulp, sulfite pulp, and soda pulp can be used.

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

Examples of the sizing agent preferably contained in the base paper preferably used in the practice of the present invention include fatty acid metal salts and / or fatty acids, alkyl ketene dimers, alkenyl or alkyl succinic anhydrides, described in JP-A-54-147211. Epoxidized higher fatty acid amides and organic fluoro compounds described in JP-A-56-109343.

Examples of the sizing agent advantageously contained in the base paper preferably used in the practice of the present invention include fatty acid metal salts and / or fatty acid metal salts which are fixed to pulp with a water-soluble aluminum salt such as aluminum chloride, bansulfate, or polyaluminum chloride. And fatty acids, water-soluble aluminum salts,
Alternatively, there may be mentioned an alkyl ketene dimer or a combination sizing agent of an alkyl ketene dimer and an epoxidized higher fatty acid amide, which is fixed to pulp without using it. The fatty acid metal salt and / or the fatty acid preferably has 12 to 22 carbon atoms, and the amount thereof is preferably in the range of 0.5 to 4.0% by weight based on the absolute dry weight of the pulp. The amount of the water-soluble aluminum salt added as needed is preferably in the range of 1/20 to 4/1, and particularly preferably in the range of 1/10 to 1/1, based on the solid weight of the sizing agent. 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 dimer is usually commercially available as an emulsion thereof, and specific examples include Acopel 360XC manufactured by Dick Hercules Co., Ltd. The amount of the alkyl ketene dimer is preferably in the range of 0.2 to 4.0% by weight based on the absolute dry weight of the pulp.

The high molecular weight compound which is advantageously incorporated into the base paper used in the practice of the present invention at the time of preparing the stock slurry includes a cationic wet paper strength enhancer and a cationic, anionic or amphoteric paper strength enhancer. As the cationic wet paper strength enhancer, a polyamine polyamide epichlorohydrin resin is preferable, and its addition amount is in the range of 0.05 to 4.0% by weight, particularly 0.15 to 1.5% by weight, based on the pulp dry weight.
Is preferable. Specific examples thereof include sponge 557H and sponge S-25 manufactured by Dick Hercules Co., Ltd.
And Epinox P-130.

Examples of the cationic, anionic or amphoteric paper strength enhancer include cationized starch described or exemplified in Japanese Patent Publication No. 60-17103, cationic polyvinyl alcohol described or exemplified in Japanese Patent Application No. 62-49699, and Showa 57-1854
No. 32, cationic polyacrylamide described or exemplified in JP-A-57-197539, JP-B-62-23119, JP-B-6-19769
Anionic polyacrylamides described or exemplified in 2-31118, amphoteric polyacrylamides described or exemplified in JP-B-61-37613 and JP-B-59-31949, JP-A-59-31949
And plant galactomannans described or exemplified in No. 125731. Their addition amount is in the range of 0.05 to 8% by weight, especially 0.15 to
A range of 4% by weight is preferred.

The base paper preferably used in the practice of the present invention may contain various additives during preparation of the stock slurry. As a filler, clay, kaolin, calcium carbonate, barium sulfate, magnesium silicate, titanium oxide, etc., as a pH regulator, caustic soda, sodium carbonate, etc., a coloring pigment, a coloring dye, a fluorescent whitening agent,
No. -147033, Japanese Patent Application No. 62-37555, and Japanese Patent Application No. 63-96516, or those described in the examples or the like can be appropriately combined.

Various water-soluble polymers, antistatic agents, and additives can be contained in the base paper preferably used in the practice of the present invention by spraying or tub size press. Examples of the water-soluble polymer include starch-based polymers, polyvinyl alcohol-based polymers, gelatin-based polymers, polyacrylamide-based polymers, and cellulose-based polymers described or exemplified in Japanese Patent Application No. 63-96516. No. 96516 or as exemplified by alkali metal salts such as sodium chloride and potassium chloride; alkaline earth metal salts such as calcium chloride and barium chloride; colloidal metal oxides such as colloidal silica;
No. 2 or exemplified organic antistatic agents, such as latex, emulsions, petroleum resin emulsion,
Styrene-acrylic acid-acrylate copolymer,
Latex such as styrene-acrylic acid-butadiene copolymer, ethylene-vinyl acetate copolymer, styrene-malenic acid-acrylic acid ester copolymer, pigments such as clay, kaolin, talc, barium sulfate, titanium oxide, etc. As a regulator, it is advantageous to incorporate an appropriate combination of additives such as hydrochloric acid, phosphoric acid, citric acid, caustic soda, sodium carbonate and the above-mentioned coloring pigments, coloring dyes, fluorescent whitening agents and the like.

For the production of base paper preferably used in the practice of the present invention,
Commonly used paper machines such as fourdrinier and round net paper machines are used, but are disclosed in JP-A-58-37642 and JP-A-61-260240.
It is advantageous to employ an appropriate papermaking method as described or exemplified in JP-A-61-284762. There is no particular limitation on the thickness of the base paper.However, after the base paper is formed, the base paper is calendered as described or exemplified in JP-A-58-37642 and JP-A-60-126397. preferably, the basis weight preferably from ^{40g / m 2 ~250g / m 2} .

Various types of back coat layers can be applied to the photographic support of the present invention for the purpose of preventing static charge and curling. In addition, the back coat layer includes
No., JP-B-57-9059, JP-B-57-53940, JP-B-58
No. -56859, JP-A-59-214849, JP-A-58-184144 and the like, or inorganic antistatic agents, organic antistatic agents, hydrophilic binders, latexes, curing agents, pigments, surfactants And the like can be appropriately combined and contained.

The photographic support in the present invention is coated with various photographic constituent layers and is used for color photographic printing paper, black and white photographic printing paper, photographic printing use, copy photographic paper, reversal photographic material, silver salt diffusion transfer method. It can be used for various applications such as negative and positive applications, printing materials and the like. For example, silver chloride, silver bromide, silver chlorobromide,
A silver iodobromide or 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 constituting layer. Further, a silver salt diffusion transfer image-receiving layer can be provided by incorporating a physical development nucleus. As a binder for these photographic constituent layers, in addition to ordinary gelatin, hydrophilic high-molecular substances such as polyvinylpyrrolidone, polyvinyl alcohol and polysaccharide sulfate compounds can be used. Further, various additives can be contained in the photographic constituent layer. For example, as sensitizing dyes, cyanine dyes, merocyanine dyes, etc., as chemical sensitizers, water-soluble gold compounds, sulfur compounds, etc., as antifoggants or stabilizers, hydroxy-triazolopyrimidine compounds, mercapto-heterocyclic compounds, etc. , Hardening agents such as formalin, vinyl sulfone compounds, and aziridine compounds; coating aids such as benzene sulfonate and sulfosuccinate; dialkyl hydroquinone compounds as antifouling agents; and other fluorescent brighteners and improved sharpness A dye, an antistatic agent, a pH adjuster, a fogging agent, and a water-soluble iridium, water-soluble rhodium compound or the like can be incorporated in the silver halide during formation and dispersion.

The silver halide photographic material according to the present invention may be exposed, developed, and stopped in accordance with the photographic material, as described in "Photosensitive Materials and Handling Methods" (Kyoritsu Shuppan, Goro Miyamoto, Photographic Technology Course 2). Processing such as fixing, bleaching, and stabilization is performed. In particular, a multi-layer silver halide color photographic material which is subjected to a single-bath bleach-fixing process after color development includes CD-III, CD-IV
(The above two compounds are trade names of Kodak Co., Ltd.) and droxychrome (trade name of May & Baker Co., Ltd.) can be treated with any color developing solution of the principal agent. The developer containing such a main agent may contain a development accelerator such as benzyl alcohol, thallium salt, phenidone,
Processing can also be performed with a developer substantially free of bezyl alcohol. A useful one-bath bleach-fix solution is a metal salt of aminopolycarboxylic acid (for example, a ferric complex salt such as ethylenediaminetetraacetic acid or propylenediaminetetraacetic acid).
It is a solution, and as a fixing agent, sodium thiosulfate, ammonium thiosulfate and the like are useful. Various additives can be contained in such a one-bath bleach-fix solution. For example, a desilvering accelerator (for example, a mercaptocarboxylic acid described in U.S. Pat. No. 3,512,979, a mercapto-heterocyclic compound described in Belgian Patent No. 682,426, etc.), a stain inhibitor, a pH regulator or a pH buffer, a hardener, Membrane agents (eg, magnesium sulfate, aluminum sulfate, potassium alum, etc.),
Various compounds such as a surfactant can be contained in combination. In addition, such a single-bath bleach-fix solution can be used in various ways.
A useful pH range that can be used at pH is pH 6.0-8.0.

〔Example〕

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

Example 1 A rutile type produced under a predetermined firing condition so as to have a particle size shown in Table 1 according to a process for producing a rutile type titanium dioxide pigment by a sulfuric acid method described in the text of the specification. The titanium dioxide clinker was pulverized and sized, and further wet pulverized and classified to obtain a titanium dioxide slurry substantially free of coarse titanium dioxide. This slurry is placed in a reaction tank, and a 10% by weight aqueous solution of CaCl ₂ .6H ₂ O is added so that the amount of the calcium compound carried on the surface of the titanium dioxide particles is 0.04% by weight calculated as calcium per titanium dioxide. Added. Thereafter, the pH of the slurry was raised to about 9.2 with sodium hydroxide, and the temperature of the slurry was heated to about 70 ° C.
An amount of aqueous sodium aluminate solution, calculated as Al ₂ O ₃ , to 0.75% by weight, based on dry titanium dioxide, was added and held for 30 minutes.

Then, the pH of the slurry was lowered to 7.0 by adding 20% 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 alumina is filtered through a filter press, and then the titanium dioxide cake in the filter press is run under running water, as defined in the text of the titanium dioxide pigment specification. The suspension was washed under predetermined washing conditions until the suspension electric conductivity reached 45 μ / cm.

Thereafter, the titanium dioxide cake is dried, impact-crushed by a hammer mill with a fixed-quantity feeder, and finely ground by a steam mill to produce rutile-type titanium dioxide pigments having different particle diameters, each carrying a calcium compound on the particle surface. did.

Thus, low density polyethylene with a density of 0.918 g / cm ³ and an MFR of 8.0 g / 10 min or a density of 0.918 g / cm ³ and an MFR of 8.0
g / 10 minutes, 50 parts by weight of low-density polyethylene containing 135 ppm of tetrakis [methylene (3,5-di-tert-butyl-4-hydroxy-hydroxynamate)] methane as an antioxidant, the above titanium dioxide pigment 50 parts by weight and 2.5 parts by weight of zinc stearate were sufficiently kneaded at 150 ° C. using a Banbury mixer to prepare a master batch of a titanium dioxide pigment.

Also, 50 parts by weight of the same low-density polyethylene as used in the preparation of the titanium dioxide pigment master batch, 50 parts by weight of the above titanium dioxide pigment, 1.25 parts by weight of ultramarine (Daiichi Kasei Kogyo Co., Ltd., # 2000) and Zinc stearate 2.5
The parts by weight were kneaded well at 150 ° C. using a Banbury mixer to prepare titanium dioxide pigment master batches containing ultramarine blue.

Further, 0.28 parts by weight of the fluorescent agent (IX) described in the text of the specification and 0.28 parts by weight of zinc stearate are mixed well in advance,
The mixture and 40 parts by weight of the same low-density polyethylene as used in the preparation of the above titanium dioxide pigment masterbatch were thoroughly kneaded at 135 ° C. using a Labo Plastomill to prepare a phosphor masterbatch.

On the other hand, a mixed stock of 50 parts by weight of hardwood bleached kraft pulp and 50 parts by weight of softwood bleached sulphite pulp was beaten to 310 ml of Canadian Standard Freeness. 0.2 parts by weight of polyacrylamide, 0.4 parts by weight of alkyl ketene dimer emulsion (as ketene dimer), 0.4 parts of polyaminopolyamide epichlorohydrin resin
By weight, a paper having a basis weight of 160 g / m ² was produced. The obtained wet paper was dried at 110 ° C., and subsequently an impregnating liquid consisting of 3 parts by weight of carboxy-modified polyvinyl alcohol, 0.05 parts by weight of fluorescent whitening agent, 0.002 parts by weight of blue dye, 0.2 parts by weight of citric acid and 97 parts by weight of water was added. 25 g / m ² was impregnated, dried with hot air at 110 ° C., was treated supercalendered in further linear pressure 90 kg / cm, both surfaces thereof with a corona discharge treatment, producing a base paper for resin-coated paper type photographic support did.

Next, high density polyethylene (density 0.960g / c
m ³ , MFR = 5g / 10min and low density polyethylene (density 0.923g / c
m ³ , MFR = 5 g / 10 min) was coated at a resin temperature of 330 ° C. using a melt extrusion coater to a thickness of 30 μm. Next, on the surface of the base paper, 18.8 parts by weight of the above-mentioned titanium dioxide pigment masterbatch, 7.2 parts by weight of a titanium dioxide pigment containing ultramarine blue, 3.0 parts by weight of a fluorescent agent masterbatch, and high-density polyethylene (density 0.970 g) as a diluting resin
/ cm ³ , MFR 7.0 g / 10 min) 20 parts by weight and low-density polyethylene (density 0.920 g / cm ³ , MFR 6.0 g / 10 min) 51 parts by weight (54 parts by weight when no fluorescent master batch is added) ) Was melt-extruded and coated at a resin temperature of 330 ° C. to a thickness of 30 μm to produce a polyethylene resin-coated paper-type photographic support of the present invention and a polyethylene resin-coated photographic support other than the present invention. At this time, the surface of the polyethylene containing the titanium dioxide pigment was processed into a completely flat glossy surface, and the surface of the back polyethylene was processed into a matte surface such as paper.

The apparent whiteness of the polyethylene resin-coated paper type photographic support thus obtained on the side containing the titanium dioxide pigment was visually evaluated. As evaluation criteria, It is.

 The die lip stain was measured as follows.

Using a screw extruder with an extrusion diameter of 65 mm and a melt extruder with a T die of 750 mm, after melt-extruding at a melting temperature of 320 ° C. and a screw rotation speed of 100 rpm for 2 hours, the number of stains generated on the die lip was counted. It was measured.

Next, in order to measure the sharpness of a printed image, a color photographic printing paper having the above-described photographic support was manufactured.
First, a back coat layer having a composition of colloidal silica: styrene-acrylic latex = 1: 1 as a dry weight component was applied on the back surface of the photographic support after corona discharge treatment at 0.4 g / m ² . Next, a blue-sensitive emulsion layer containing a yellow color coupler after corona discharge treatment on the front side resin surface containing a titanium dioxide pigment of a photographic support, an intermediate layer containing a color-blinding inhibitor, a green-sensitive emulsion layer containing a magenta color coupler, A color printing paper was obtained by providing an ultraviolet absorbing layer containing an ultraviolet absorbing agent, a red-sensitive emulsion layer containing a cyan coloring coupler, and a protective layer. Each color-sensitive emulsion layer comprises a silver chlorobromide which corresponds to 0.6 g / m ² with silver nitrate, further formation of the silver halide, other gelatin required dispersion and film formation, an appropriate amount of antifoggants, the sensitizing dye, Contains coating aids, hardeners, thickeners and appropriate amounts of filter dyes.

A resolving power chart was adhered to the obtained photographic printing paper, exposed to green light, and subjected to color development to obtain a test sheet.
This test sheet was measured with a microdensitometer, calculated by a personal computer according to a conventional method, and the image of the magenta layer was defined as sharpness by CTF (Contrast Transf
er Function; contrast transfer function) was determined, and the sharpness of the printed image of the photographic support was determined. The CTF indicates that the larger the value, the higher the sharpness of the print image.

 Table 1 shows the obtained results.

As can be seen from Table 1, in the resin layer on the side of the resin-coated paper-type photographic support on which the image is formed, the particle diameter of the titanium dioxide pigment was determined by the number-average diameter measured by a directional microscope using an electron microscope. 0.110 μm to 0.150 μm,
The photographic support of the present invention (samples No. 12 to No. 17) containing a titanium dioxide pigment carrying a calcium compound on the particle surface and an antioxidant has high sharpness of a printed image, In addition, it is understood that die lip stain is less generated during the production of the photographic support, and therefore the photographic support is excellent in surface quality and excellent. In particular, the particle size is 0.115μ
A photographic support containing a titanium dioxide pigment having a particle size of m to 0.135 μm in a resin layer (samples No. 13 to No. 16) has a particularly high sharpness of a printed image and extremely generates a die lip stain. It turns out that it is few and it is especially excellent. Further, a photographic support containing a fluorescent agent in the resin layer of the photographic support (samples No. 12 to No. 14, No. 16 to No. 17)
Is a photographic support containing no fluorescent agent (Sample No. 1
As compared with 5), it is apparent that the photographic support is excellent in appearance and particularly excellent.

On the other hand, photographic supports (samples No. 1 to No. 11, N
o.18 to No.19) have problems.

That is, the photographic support containing no antioxidant in the resin layer (samples No. 1 to No. 9) is problematic due to the large amount of die lip contamination, and the antioxidant in the resin layer. Even if it contains a titanium dioxide pigment having a particle size of less than 0.110 μm (samples No. 10 to No. 11),
In addition, the occurrence of die lip is large, while the particle diameter is 0.150μ.
Those containing a titanium dioxide pigment larger than m (samples Nos. 18 to 19) have a problem in that the sharpness of the printed image is low.

Example 2 In Example 1, the particle diameter of the titanium dioxide pigment in the resin of the resin-coated paper-type photographic support was 0.124 μm in terms of the number-average diameter measured in a directional direction by an electron microscope, and the particle surface thereof. Example 1 except that a titanium dioxide pigment carrying the amount of calcium compound calculated in the form of calcium per titanium dioxide and shown in Table 2 was used.
Was performed in the same manner as in Sample No. 14.

 Table 2 shows the obtained results.

As can be seen from Table 2, as a titanium dioxide pigment in the resin layer of the resin-coated paper type photographic support, 0.004% by weight to 0.1% by weight of a calcium compound calculated on the particle surface in the form of calcium per titanium dioxide. The photographic support according to the present invention (samples No. 23 to No. 27) containing a titanium dioxide pigment carrying a dye has a high sharpness of a printed image and has a dilip stain during the production of the photographic support. This indicates that the resulting photographic support is excellent in surface quality with little occurrence. On the other hand, a photographic support (sample) other than the present invention using a titanium dioxide pigment carrying a calcium compound in an amount of less than 0.004% by weight or more than 0.1% by weight calculated as calcium per titanium dioxide on the particle surface. No.2
No. 22 and No. 28) are problematic because the sharpness of the printed image is low and the occurrence of die lip stains is large.

Example 3 As a low-density polyethylene resin for a masterbatch, tetrakis [methylene (3,5-di-tert-butyl) was used as an antioxidant in the low-density polyethylene resin for a masterbatch used in Sample No. 14 of Example 1. -4-Hydroxy-hydrocinnate)] Example 1 except that methane was previously blended so as to have the amount shown in Table 3.
Was performed in the same manner as in Sample No. 14.

 Table 3 shows the obtained results.

As can be understood from Table 3, the occurrence of die lip stain is well prevented by including an antioxidant in the resin layer of the resin-coated paper-type photographic support. The content is 10 to 1000 with respect to the resin composition.
It is understood that a range of ppm is preferable, and a range of 20 to 500 ppm is particularly preferable. As described above, the photographic support of the present invention containing an appropriate amount of an antioxidant has a high sharpness of a printed image, and has very little occurrence of stain on a die lip during production of the photographic support. It can be seen that this is a good and excellent photographic support.

Example 4 Instead of the titanium dioxide pigment used in Example 2, the particle size expressed by number average particle size measured by a directional measurement using an electron microscope was 0.124 μm, and various amounts of magnesium compound or Example 2 was repeated except that a titanium dioxide pigment supporting a barium compound was used.

At that time, a titanium dioxide pigment was produced in the same manner as in Example 1, and instead of CaCl ₂ .6H ₂ O used in Example 1, MaSO ₄ .7H ₂ O was used.
Alternatively, BaCl ₂ .2H ₂ O was used.

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

Example 5 Instead of the antioxidant tetrakis [methylene (3,5-di-tert-butyl-4-hydroxy-hydrocinnamate)] methane used in Example 2, octadecital-3,5
Di-tert-butyl-4-hydroxy-hydrocinnamate, 2,2 ', 2 "-tris [(3,5-di-tert-butyl-
4-Hydroxyphenyl) propionyloxy] ethyl isocyanurate or 1,3,5-tris (4-tert-butyl-3-hydroxy-2,6-dimethylbenzyl) isocyanurate except for using Example 3. And
The same results as in Example 3 were obtained.

Example 6 Example 6 was carried out in the same manner as in Example 1 except that the following anatase type titanium dioxide pigment was used instead of the rutile type titanium dioxide pigment used in Example 1.

Anatase produced under hydrolysis conditions and calcination conditions predetermined to have the particle diameters shown in Table 4 according to the production process of anatase type titanium dioxide pigment by the sulfuric acid method described in the text of the specification The titanium dioxide clinker was pulverized and sized, and further wet pulverized and classified to obtain a titanium dioxide slurry substantially free of coarse titanium dioxide. This slurry is placed in a reaction tank, and CaCl ₂ .6H ₂ O is added so that the amount of the calcium compound carried on the surface of the titanium dioxide particles is 0.04% by weight, calculated as calcium per titanium dioxide.
Of a 10% by weight aqueous solution is added. Thereafter, surface treatment with hydrous aluminum hydroxide was carried out in the same manner as in Example 1, followed by subsequent washing / drying and fine pulverization to produce anatase-type titanium dioxide pigments having a different particle diameter and carrying a calcium compound on the particle surface. did.

 Table 4 shows the obtained results.

As can be seen from Table 4, the particle diameter of the titanium dioxide pigment is 0.110 μm to 0.150 μm in the resin layer on the image forming side of the resin-coated paper type photographic support, and The photographic support of the present invention (samples No. 42 to No. 43) containing a titanium dioxide pigment carrying a calcium compound and an antioxidant has a high print image sharpness and a high photographic support. It can be seen that there is little occurrence of dilip stains during the production of the body, and therefore it is an excellent photographic support having good surface quality.

On the other hand, photographic supports (samples No. 38 to No. 41, out of the present invention)
No. 44) has problems.

That is, the photographic support containing no antioxidant in the resin layer (samples No. 38 to No. 40) is problematic because of a large amount of die lip stain, and the antioxidant is contained in the resin layer. In the case of containing titanium dioxide pigment having a particle size of less than 0.110 μm (Sample No. 41), the occurrence of die lip stain is still large and the sharpness of the printed image is low. The sample containing titanium dioxide pigment having a particle size larger than 0.150 μm (Sample No. 44) has a problem that the sharpness of the printed image is low.

Example 7 A sample was prepared in the same manner as in Sample No. 43 of Example 6, except that the following anatase type titanium dioxide pigment was used instead of the anatase type titanium dioxide pigment used in Sample No. 43 of Example 6.

Hydrolysis determined in advance so that the particle diameter expressed by number average in a directional measurement with an electron microscope according to the manufacturing process of anatase type titanium dioxide pigment by the sulfuric acid method described in the text of the specification is 0.122 μm The anatase type titanium dioxide clinker produced under the conditions and firing conditions was pulverized and sized, and further wet pulverized and classified to obtain a titanium dioxide slurry substantially free of coarse titanium dioxide. This slurry is put into a reaction tank, and 10 parts of CaCl ₂ .6H ₂ O is added so that the amount of the calcium compound carried on the surface of the titanium dioxide particles is 0.04% by weight, calculated as calcium per titanium dioxide.
A weight percent aqueous solution was added.

Thereafter, the pH of the slurry was adjusted to about 9.
2, after heating the temperature of the slurry to about 70 ° C., with respect to titanium dioxide on a dry basis, Al ₂ O ₃ and / or S
An aqueous solution of sodium aluminate or / and sodium silicate was added in an amount to give the weight% shown in Table 5 in the form of iO ₂ and kept for 30 minutes. In the case of performing surface coating treatment with hydrous titanium oxide, before raising the pH of the titanium dioxide slurry with sodium hydroxide, calculate the titanium dioxide on a dry basis in the form of TiO ₂ with respect to titanium dioxide and enter the values in Table 5. An aqueous solution of titanyl sulfate was added in an amount to give a weight% of the above.

Then, the pH of the slurry was lowered to 7.0 by adding 20% sulfuric acid, and the slurry was aged for 2 hours. After aging, the first mother liquor of the titanium dioxide slurry surface-treated with the hydrated metal oxide is filtered with a filter press, and then the titanium dioxide cake in the filter press is run under running water, as defined in the text of the titanium dioxide pigment specification. Washing was performed under predetermined washing conditions until the suspended electric conductivity was 45 μ / cm.

After that, the titanium dioxide cake was dried, subjected to impact pulverization with a hammer mill with a fixed-quantity feeder, and finely pulverized with a steam mill.The particle diameter was 0.122 μm, and a calcium compound was supported on the particle surface. Anatase type titanium dioxide pigments having different types and treatment amounts of the products were produced.

 Table 5 shows the obtained results.

As can be seen from Table 5, as the titanium dioxide pigment in the resin layer of the resin-coated paper-type photographic support, the particle diameter was 0.
In the range of 110 μm to 0.150 μm, and the particle surface carries a specific amount of a calcium compound, and the particle surface is more than 0.2% by weight calculated as anhydrous metal oxide per titanium dioxide A photograph according to the present invention containing less than 1.8% by weight of a titanium dioxide pigment which has been treated with a hydrated metal oxide containing at least aluminum atoms and having a silicon dioxide content of not more than 0.4% by weight (including 0). The support for samples (Sample Nos. 45 to No. 53) has less occurrence of die lip stains during the production of the photographic support, and therefore has good surface quality, high sharpness of the printed image, and has a good appearance. It can be seen that this is an excellent white photographic support. Further, from the viewpoint of preventing die lip stains remarkably and obtaining high sharpness, a preferable treatment amount range is 0.35% by weight to 1.5% by weight of titanium dioxide calculated in the form of anhydrous metal oxide. Range, particularly preferably,
It can be seen that the range is from 0.5% by weight to 1.25% by weight. Further, as the hydrated metal oxide, it is particularly preferable to perform a surface treatment with hydrated aluminum oxide, and when treated with hydrated silicon dioxide, a treatment amount of less than 0.2% by weight calculated in the form of SiO ₂ is preferred. I can tell.

On the other hand, a photographic support outside the present invention (samples No. 54 to No. 58)
It is understood that each has a problem. That is,
As the titanium dioxide pigment in the resin layer of the resin-coated paper-type photographic support, a pigment whose surface has been surface-treated with 0.2% by weight or less of a hydrated metal oxide calculated as a metal anhydride per titanium dioxide is used. (Sample No. 54) is problematic because the sharpness of the printed image is low and the whiteness tends to decrease. On the other hand, the surface is calculated in the form of metal anhydride per titanium dioxide. When a material surface-treated with at least 1.8% by weight of a hydrated metal oxide is used (Sample No. 55, No.
57) and in the case of using a material which is surface-treated with more than 0.4% by weight of hydrous silicon oxide in the form of SiO ₂ per titanium dioxide (samples No. 56, No. 58), the generation of die lip stain is remarkable. Further, it can be seen that the sharpness of the printed image is reduced, which is a problem.

〔The invention's effect〕

According to the present invention, it is possible to provide an excellent resin-coated paper-type photographic support having a high sharpness of a printed image, extremely low generation of die lip stains during the production of the photographic support, and therefore having a good surface quality.

Claims (15)

(57) [Claims] 1. A resin-coated paper-type photographic support in which at least one surface of paper, synthetic paper or a film substrate is coated with a polyolefin resin composition, wherein the polyolefin resin composition is at least (A) oriented in an electron microscope. A titanium dioxide pigment having a particle diameter of 0.110 μm to 0.150 μm represented by a number average diameter in the above, and a magnesium compound of 0.004% by weight to 0.1% by weight calculated on the surface of the particle in the form of metal per titanium dioxide; A titanium dioxide pigment carrying a calcium compound or a barium compound, the particle surface of which is greater than 0.2% by weight and less than 1.8% by weight of at least aluminum, calculated in anhydrous metal oxide form per titanium dioxide Titanium dioxide containing atoms and treated with a hydrated metal oxide having a silicon dioxide content of 0.4% by weight or less (including 0) A photographic support comprising a pigment and (B) an antioxidant. 2. Titanium dioxide pigment having a particle surface of 0.35% by weight calculated as anhydrous metal oxide per titanium dioxide.
2. The photographic support according to claim 1, wherein the photographic support is treated with an amount of at least 1.5% by weight and containing at least aluminum atoms, and as a silicon dioxide component, at most 0.4% by weight (including 0) of a hydrated metal oxide. body. 3. A titanium dioxide pigment having a particle surface of 0.35% by weight calculated as anhydrous metal oxide per titanium dioxide.
2. The photographic support according to claim 1, wherein the photographic support has been treated with a hydrated metal oxide containing at least aluminum atoms in an amount of at least 1.25% by weight and containing less than 0.2% by weight (including 0) of silicon dioxide. body. 4. The photographic support according to claim 1, wherein the hydrous metal oxide is hydrous aluminum hydroxide. 5. The photographic support according to claim 1, wherein the titanium dioxide pigment has a rutile structure. 6. The photographic support according to claim 1, wherein the titanium dioxide pigment is pulverized by a fluid energy mill. 7. The photographic support according to claim 6, wherein the fluid energy mill is a steam mill. 8. The photographic support according to claim 1, wherein the antioxidant is a hindered phenol-based antioxidant. 9. The composition according to claim 1, wherein the content of the antioxidant is from 10 ppm to 1000 ppm based on the polyolefin resin composition.
3. The photographic support according to 3, 4, 5, 6, 7 or 8. 10. The photographic support according to claim 1, wherein the polyolefin resin is a polyethylene resin. 11. A polyolefin resin composition comprising a higher fatty acid metal salt.
The photographic support according to 5, 6, 7, 8, 9 or 10. 12. The composition according to claim 1, wherein the polyolefin resin composition contains a fluorescent agent.
The photographic support according to 8, 9, 10 or 11. 13. The photographic support according to claim 12, wherein the fluorescent agent is a substituted bis (benzoxazolyl) naphthalene-based fluorescent agent or a substituted bis (benzoxazolyl) stilbene-based fluorescent agent. . 14. The method of claim 12 or 13 photographic support according content of the fluorescent agent is ^{0.3mg / m 2 ~30mg / m 2} . 15. The method according to claim 1, wherein the content of titanium dioxide is 9% by weight to 30% by weight based on the polyolefin resin composition. 11, 12, 13
Or the photographic support according to 14.