JP2871356B2 - Photographic paper support - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a photographic printing paper support. More specifically, the present invention relates to a photographic printing paper support that does not cause fogging on photographic printing paper during development processing.

[0002]

2. Description of the Related Art Conventionally, as a support for photographic printing paper, a so-called baryta paper manufactured by applying a white pigment such as barium sulfate to the surface of a paper having strong size and high strength has been used. Was used.

However, in recent years, polyolefin resin-coated supports manufactured by forming a resin coating layer made of a polyolefin resin (hereinafter referred to as a resin coating layer) on both sides of a paper base have been widely used instead of baryta paper. It has come to be used. In such a photographic printing paper support, since the resin coating layer is hydrophobic and waterproof, the obtained photographic printing paper support has a processing solution during the development and fixing process, as compared with the baryta paper. It hardly penetrates into the support, so that the washing time and drying time are greatly reduced, and since there is no permeation of the treatment liquid into the paper substrate, expansion and contraction of the support itself is suppressed, and its dimensional stability is improved. It has such advantages.

However, when a photographic printing paper produced by applying a photographic emulsion to the above-mentioned polyolefin resin-coated photographic printing paper support is used, if it is used after being stored for a long period of time, it is ignored as a product. There is a problem that fog is generated to the extent that it cannot be performed. As a method of preventing this fog, Japanese Patent Application Laid-Open No. 55-103549 proposes adding water-soluble iodine to a sheet-like substrate, but the effect is not sufficient and is not always satisfactory.

[0005]

SUMMARY OF THE INVENTION The present invention solves the above-mentioned problems of the conventional support for polyolefin resin-coated photographic printing paper, and produces a photographic printing paper free from fogging even when stored for a long period of time. The purpose of the present invention is to provide a support for photographic printing paper which is suitable for use in photographic printing.

[0006]

The photographic printing paper support of the present invention comprises, as constituent elements, a sheet-like substrate and a surface provided on both front and back surfaces of the sheet-like substrate and containing a polyolefin resin as a main component. the side and the back side resin coating layer is formed on the surface side resin coating layer, and the film-forming
A subcoat layer containing as a main component sex polymeric material, wherein
Film-forming polymer formed on the backside resin coating layer
A back coat layer containing a material as a main component, wherein at least one of the constituent elements contains magnesium hydroxide .

In the photographic printing paper support of the present invention, it is preferable that the sheet-like substrate has a size press coating layer containing magnesium hydroxide .

[0008]

The cause of fogging when photographic paper produced using a polyolefin resin-coated support is stored for a long period of time has not been fully elucidated. It is considered that the substance causing fog is diffused into the photographic emulsion layer from the resin coating layer or another coat layer and reacts with the photographic emulsion to generate fog.

The present inventors have intensively studied means for preventing the substance causing the fogging from transferring to the photographic emulsion layer over time, and have completed the present invention. That is, it has been found that by including magnesium hydroxide in at least one of the constituent elements of the photographic printing paper support, it is possible to prevent a substance affecting fogging from migrating to the photographic emulsion layer and to preserve it for a long time. Thus, the present invention succeeded in obtaining a support for photographic printing paper which did not cause fogging even if development processing was performed later. Although the mechanism of the fogging suppression effect of magnesium hydroxide has not been fully elucidated yet, magnesium hydroxide captures (adsorbs) the substance that causes fog, fixes it, and transfers it to the photographic emulsion layer. It is thought to prevent.

In the present invention, in order to prevent fog,
Magnesium hydroxide is used.

In the present invention, the layer containing magnesium hydroxide may be any layer as long as it is a component of a photographic printing paper support. That is, in the present invention,
Magnesium hydroxide is used as a component of a photographic paper support, namely, a sheet-like substrate, a resin-coated layer on the front side (the side on which the photographic emulsion layer is formed) of the sheet-shaped substrate, and a backside (the photographic emulsion layer is formed). A side opposite to the side to be coated) resin coating layer, further, a sub-coat layer formed on the surface side resin coating layer for the purpose of improving the adhesion between the surface side resin coating layer and the photographic emulsion layer, and / or It may be contained in at least one layer such as a backcoat layer formed on the surface of the backside resin coating layer for the purpose of imparting writability and conductivity to the photographic printing paper.

When the sheet-like substrate is made of base paper produced by making pulp raw material, it can be contained in a size press coating layer formed on the base paper surface in the size press step. Further, a layer containing magnesium hydroxide may be provided separately from the layer constituting the photographic printing paper support.

In the present invention, magnesium hydroxide is
It may be contained in any one of the layers constituting the photographic printing paper support, or may be contained in two or more layers. When magnesium hydroxide is contained in the resin coating layer in the present invention, the magnesium compound may be blended alone, or may be blended together with other pigments and additives.

Normally, titanium dioxide is blended in the resin coating layer on the surface side of the sheet-like substrate in order to secure the whiteness and hiding properties required for a photographic printing paper support. Magnesium hydroxide may be appropriately mixed with and mixed with this titanium dioxide. The resin coating layer of the present invention, in addition to the above titanium dioxide,
If necessary, calcium carbonate, zinc oxide, talc, clay, barium sulfate, and aluminum oxide, white pigments such as calcium hydroxide, glass fibers, fibrous fillers such as whiskers, carbon black, phthalocyanine pigments, graphite, It may contain coloring pigments such as titanium yellow, red iron oxide, ultramarine blue, etc., stabilizers, antioxidants, antistatic agents, plasticizers, dispersants, lubricants, fluorescent agents and the like.

The backside resin coating layer can also contain various additives similar to those used in the above-mentioned frontside resin coating layer. Only antioxidants and lubricants are added.

The mixing amount of magnesium hydroxide in the resin coating layer on the front side or the back side is preferably 0.5% by weight to 5% by weight. When the amount is less than 0.5% by weight, a sufficient fog suppression effect cannot be imparted to the obtained photographic printing paper. Also, if it is mixed more than 5% by weight,
In addition to difficulty in dispersing in a polyolefin resin, defects such as film cracking may occur in the obtained coating layer, which is not practical.

In the photographic printing paper support of the present invention, the coating amount of the surface-side resin coating layer is preferably 25 to 40 g / m ² . If the coating amount is less than 25 g / m ² , it will be difficult to sufficiently cover the irregularities on the surface of the sheet-like substrate. Further, even if it is applied in a large amount exceeding 40 g / m ² , the above effect is not improved, and the whole photographic printing paper becomes too thick, and disadvantages such as an increase in cost arise. Sometimes.

In the photographic printing paper support of the present invention, the coating amount of the backside resin coating layer is not particularly limited, but is generally preferably in the range of 10 to 40 g / m ² . When the coating amount is less than 10 g / m ² , it is difficult to obtain sufficient water resistance and sufficient adhesiveness between the sheet-like substrate and the resin coating layer. If the amount exceeds 40 g / m ² , the resulting photographic paper support may become too thick to be practically useful.

In the present invention, the polyolefin resin used for the front and back side resin coating layers includes homopolymers of ethylene and α-olefins, for example, propylene, copolymers of at least two kinds of the olefins, and And a mixture of at least two kinds of polymers of the above. Particularly preferred polyolefin resins are low density polyethylene, high density polyethylene, linear low density polyethylene, and mixtures thereof. Although the molecular weight of the polyethylene resin used in the present invention is not particularly limited, it is usually preferable to use one having a molecular weight in the range of 20,000 to 200,000.

In the support for photographic printing paper of the present invention, the surface side resin coating layer usually contains about 10 to 20% of titanium dioxide as an inorganic white pigment. The titanium dioxide may be either rutile type or anatase type, but it is advantageous to use anatase type titanium dioxide from the viewpoint of whiteness. Titanium dioxide may be produced by any of a sulfuric acid method and a chlorine method. In addition, the surface is treated with an inorganic surface treating agent such as, for example, hydrous aluminum hydroxide, treated with an organic surface treating agent such as organopolysiloxane, or surface treated by appropriately combining an inorganic surface treating agent and an organic surface treating agent. It is also possible to use the applied titanium dioxide.

The front and back resin coating layers of the present invention are usually formed by melt extrusion lamination. The slit die for melt extrusion coating used in the polyolefin resin coating step includes a T-type die and an L-type die.
A flat die such as a mold die is preferred. In order to improve the adhesiveness between the resin coating layer and the sheet-like substrate, prior to the melt extrusion lamination, the sheet-like substrate is subjected to a surface activation treatment such as a corona discharge treatment or a flame treatment, or an anchor treatment by applying a chemical. Is not a problem.

In the present invention, magnesium hydroxide is
When contained in a coating layer other than the front and back side resin coating layer, for example, a subcoat layer, or a backcoat layer, magnesium hydroxide and an adhesive resin having a film forming ability are dissolved and dispersed in water or an organic solvent. To prepare a coating solution, and apply and dry the coating solution on a predetermined surface to form a coating layer.

The polymer material having a film-forming ability used in the present invention includes gelatin and its derivatives,
Colloidal albumin, agar, acacia, starch and its derivatives, alginic acid, cellulose derivatives such as cellulose acetate and hydroxyethyl cellulose,
Polyacrylamide, imidized polyacrylamide,
Casein, a vinyl alcohol polymer or a vinyl alcohol copolymer, a copolymer of a protein and a monomer having a vinyl group, polyvinyl pyridine, polyvinyl amine, polyaminoethyl methacrylate, polyethylene imine, or the like can be used.

As the film-forming polymer material, acrylic polymer, polyvinyl acetate emulsion, styrene-butadiene copolymer, acrylonitrile-butadiene copolymer, carboxy-modified acrylonitrile-butadiene copolymer, vinylidene chloride-based polymer Latexes such as amphoteric latex and acrylic polymer can also be used.

The coating layer (subcoat layer and backcoat layer) of the present invention may further contain, if necessary, a crosslinking agent, a surfactant, various pigments, a conductive agent, a pH regulator, an antifoaming agent, a decay inhibitor. And various additives such as a thickener.

In the present invention, the amount of the coating layer is not particularly limited as long as the antifogging effect is exerted. Generally, the coating amount of magnesium hydroxide is 0.1 g / m ² in terms of dry weight. It is preferably 10.0 g / m ² . Antifogging effect of the coating amount of the magnesium hydroxide photographic paper obtained is less than 0.1 g / m ² is not sufficient, and also it was much applied beyond the 10.0 g / m ^2, more Not only is the effect not expected, but the support for the photographic printing paper becomes too thick, which undesirably raises the cost unnecessarily.

The coating layer containing magnesium hydroxide of the present invention can be formed by applying and drying by various methods. For example, after applying by a rod coating method, a blade coating method, a roll coating method, a reverse roll coating method, a gravure coating method, a flexographic gravure coating method, a gate roll method, an air knife coating method, a slit die coating method, and the like, a straight tunnel method It can be dried by heating using various methods such as hot air, infrared rays, microwaves, etc., by a method such as an arch method, an air loop method, a sine curve air float method, or the like.

As the sheet-like substrate used in the present invention, paper is usually used, and any substrate generally used for photographic printing paper can be used. For example, natural pulp paper, synthetic pulp paper, mixed paper of natural pulp and synthetic pulp, and various kinds of laminated paper can be used. In general, natural pulp paper mainly containing hardwood pulp, softwood pulp, hardwood softwood mixed pulp and the like is widely used. These are digested by known methods such as the kraft pulp method, the sulfite pulp method and the soda pulp method, and are subjected to chlorination, alkali treatment, hypochlorite treatment, chlorine dioxide treatment, hydrogen peroxide treatment, hydrosulfite treatment. It is manufactured by making paper using bleached pulp by a treatment or a method combining these as appropriate. If necessary, synthetic pulp and base paper produced from pulp containing synthetic fibers can also be used.

The sheet-like substrate used in the present invention includes a dry paper strength enhancer (cationized starch, cationized polyacrylamide, anionized polyacrylamide, etc.), a sizing agent (fatty acid salt, rosin) generally used for papermaking. ,
Maleated rosin cationized sizing agent, reactive sizing agent, etc.), filler (clay, kaolin, etc.), wet paper strength agent (melamine resin, epoxidized polyamide resin, etc.),
Fixing agent (aluminum sulfate, cationized starch, etc.), pH
Regulators (caustic soda, sodium carbonate, etc.), antistatic agents,
It may contain one or more additives such as dyes. In addition, the base paper is a tub-sized, processing solution containing at least one of a water-soluble polymer additive, a surface sizing agent, a surface paper strength agent, an antistatic agent, an inorganic electrolyte, a hygroscopic substance, a pigment, and a pH adjuster. It may be size-pressed. The sheet-like substrate used in the present invention contains magnesium hydroxide,
Alternatively, it may be composed of a paper base layer that does not include the above, and a magnesium hydroxide-containing size press coating layer formed thereon.

There is no particular limitation on the type and thickness of the sheet-like substrate. However, after the sheet-like substrate is manufactured, it is preferably compressed by applying pressure using a calender or the like to improve the surface smoothness. The amount is 50-250g /
m ² and the thickness are preferably 40 to 270 μm.

[0031]

The present invention will be described in more detail with reference to the following Examples, which, of course, are not intended to limit the present invention.

Example 1 Coniferous sulphite pulp (NBSP) having a Canadian standard freeness of 250 ml and broadleaf sulphate pulp (LBKP) having a Canadian standard freeness of 280 ml were mixed at a weight ratio of 2: 8. A pulp slurry having a concentration of 0.5% was prepared. The following papermaking additives were added to the pulp slurry in the following amounts based on the absolute dry weight of the pulp, and were sufficiently stirred and dispersed. Component content (weight) Cationized starch 2.0% Alkyl ketene dimer resin 0.4% Anionized polyacrylamide resin 0.1% Polyamide polyamine epichlorhydrin resin 0.7% Caustic soda pH adjusted to 7.5

A base paper is made by using a fourdrinier machine using the above raw material slurry, and then the base paper is provided with a carboxyl-modified polyvinyl alcohol (trade name: T-330, manufactured by Nippon Gosei).
H) and sodium chloride in a 2: 1 ratio of 5%
The size press coating solution with a solid content of 1.2 g
/ M ² , after application and drying and size press treatment, machine calendering and basis weight 170 g
/ M ² , a strength of 1.0 g / cm ³ , and a sheet-like substrate made of paper having a water content of 8.0%.

Next, after the front and back surfaces of the sheet-shaped substrate are subjected to corona discharge treatment, the following resin composition for forming a front-side resin coating layer and the following resin composition for forming a rear-side resin coating layer are mixed and dispersed with a Banbury mixer. The composition was laminated on both sides of a sheet-like substrate at a temperature of 320 ° C. by a melt extruder having a T-type die, and a 35 μm-thick front-side resin coating layer and a 30 μm-thick back-side resin coating layer were formed. A photographic paper support having the same was prepared.

The surface resin coating layer-forming resin composition Ingredient weight linear low density polyethylene resin 50 parts by weight (density: 0.926g / cm ^3, melt index: 16g / 10 min) Low density polyethylene resin 50 Parts by weight (density: 0.918 g / cm ³ , melt index: 4 g / 10 minutes) 15 parts by weight of anatase type titanium dioxide (manufactured by Ishihara Sangyo, trademark: A-220) magnesium hydroxide 3 parts by weight zinc stearate 0.1 Parts by weight Antioxidant 0.03 parts by weight (trade name: Irganox 1010, manufactured by Ciba Geigy)

The back side resin coating layer-forming resin composition Ingredient weight high density polyethylene resin 50 parts by weight (density: 0.951g / cm ^3, melt index: 9 g / 10 min) Low density polyethylene resin 50 parts by weight ( (Density: 0.918 g / cm ³ , melt index: 4 g / 10 minutes) 3 parts by weight of magnesium hydroxide 0.1 part by weight of zinc stearate 0.03 parts by weight of antioxidant (trade name: Irganox 1010, manufactured by Ciba Geigy)

After subjecting the surface of the resin coating layer on the surface of the photographic printing paper support obtained as described above to a corona discharge treatment, a black-and-white photographic emulsion (trade name, manufactured by Fuji Photo Film Co., Ltd., under full darkness)
Art Emulsion) was applied so that the film thickness after drying was 5 μm, to produce a photographic printing paper.

The obtained photographic printing paper is subjected to heat-accelerated aging treatment at 50 ° C. for 72 hours in place of long-term storage, followed by development, stop, fixation, and water washing under the following conditions. After applying Macbeth densitometer (Kollmorgen Cor
The density of the unexposed portion was measured using a trade name: Model No. RD-914, manufactured by p. Co., Ltd., and the measured value was used to indicate the fog density. If the fog density is 0.25 or less, there is no practical problem. Table 1 shows the test results.

Developing conditions Developing solution: D-72 formulation of Eastman Kodak (developing solution: water = 1: 2) Temperature: 20 ° C., Developing time: 90 seconds Stopping condition Stopping solution: 1.5% glacial acetic acid temperature : 20 ° C., immersion time: 20 seconds Fixing conditions Fixing solution: Formulation of F-5, Eastman Kodak Temperature: 20 ° C., Developing time: 10 minutes Rinse with water at 20 ° C. for 15 minutes

Example 2 A photographic paper support was produced in the same manner as in Example 1.
However, the amount of magnesium hydroxide in the resin composition for forming the front side resin coating layer is 5 parts by weight, and the amount of magnesium hydroxide in the resin composition for forming the back side resin coating layer is 5 parts by weight, Further, the thickness of the surface side resin coating layer is set to 25μ.
m, and the thickness of the backside resin coating layer was 15 μm. Table 1 shows the test results performed in the same manner as in Example 1.

Example 3 A photographic printing paper support was prepared in the same manner as in Example 1.
However, the amount of magnesium hydroxide in the resin composition for forming the front side resin coating layer is 1 part by weight, and the amount of magnesium hydroxide in the resin composition for forming the back side resin coating layer is 1 part by weight, Further, the thickness of the surface side resin coating layer is set to 40 μm.
m, and the thickness of the backside resin coating layer was 30 μm. Table 1 shows the test results performed in the same manner as in Example 1.

Example 4 A photographic printing paper support was produced in the same manner as in Example 1.
However, 5 parts by weight of magnesium hydroxide was added to the resin composition for forming the front-side resin coating layer, and the magnesium compound and zinc stearate were not added to the resin composition for forming the rear-side resin coating layer. Further, the thickness of the front side resin coating layer is set to 35 μm, and the thickness of the back side resin coating layer is set to 30 μm.
And Table 1 shows the test results performed in the same manner as in Example 1.
Shown in

Comparative Example 1 A photographic printing paper support was produced in the same manner as in Example 1.
However, 5 parts by weight of magnesium oxide was added as a magnesium compound to the resin composition for forming the front-side resin coating layer, and the magnesium compound and zinc stearate were not added to the resin composition for forming the back-side resin coating layer. Was.
Further, the thickness of the front side resin coating layer was 35 μm, and the thickness of the back side resin coating layer was 25 μm. Table 1 shows the test results performed in the same manner as in Example 1.

Comparative Example 2 A photographic printing paper support was produced in the same manner as in Example 1.
However, a magnesium compound was not blended in the resin composition for forming the front side resin coating layer, and 5 parts by weight of magnesium carbonate was blended in the resin composition for forming the rear side resin coating layer as a magnesium compound. Further, the thickness of the front side resin coating layer was set to 40 μm, and the thickness of the back side resin coating layer was set to 40 μm. Table 1 shows the test results performed in the same manner as in Example 1.

Comparative Example 3 A photographic printing paper support was produced in the same manner as in Example 1.
However, 3 parts by weight of magnesium sulfate was added to the resin composition for forming the front-side resin coating layer as a magnesium compound, and 3 parts by weight of magnesium sulfate was added to the resin composition for forming the rear-side resin coating layer.
Further, the thickness of the front side resin coating layer was set to 35 μm, and the thickness of the back side resin coating layer was set to 30 μm. Table 1 shows the test results performed in the same manner as in Example 1.

Comparative Example 4 A photographic printing paper support was produced in the same manner as in Example 1.
However, the magnesium compound was not blended in the resin composition for forming the front side resin coating layer and the resin composition for forming the rear side resin coating layer. Further, the thickness of the surface side resin coating layer is set to 3
5 μm, and the thickness of the backside resin coating layer was 30 μm. Table 1 shows the test results performed in the same manner as in Example 1.

Comparative Example 5 A photographic printing paper support was produced in the same manner as in Example 1.
However, 5 parts by weight of barium hydroxide was added to the resin composition for forming the front-side resin coating layer instead of the magnesium compound, and the resin composition for forming the back-side resin coating layer was replaced with hydroxide instead of the magnesium compound. 3 parts by weight of barium was blended. Further, the thickness of the surface side resin coating layer is 35 μm,
The thickness of the backside resin coating layer was 30 μm. Table 1 shows the test results performed in the same manner as in Example 1.

[0048]

[Table 1]

Example 5 A base paper was made in the same manner as in Example 1. A 5% size size press coating solution having the following composition was applied to the obtained base paper,
The solid content was applied and dried so that the applied amount became 3.5 g / m ² and subjected to a size press treatment, followed by machine calendering to obtain a basis weight of 170 g / m ² and a tightness of 1.0 g / m ² .
A sheet substrate made of paper having cm ³ and a water content of 8.0% was prepared.

The size press coating liquid composition Ingredient weight carboxy-modified polyvinyl alcohol 50 parts by weight (trademark: T-330H, Nippon Synthetic Ltd.) Magnesium hydroxide 30 parts by weight of sodium chloride 20 parts by weight

After subjecting one surface of the sheet-like substrate to a corona discharge treatment, a high-density polyethylene resin (having a density of 0.
950, melt index 9 g / 10 min) and 50 parts by weight of a low-density polyethylene resin (density 0.918, melt index 4 g / 10 min) to which a small amount of an antioxidant is added and mixed and dispersed to prepare a polyolefin resin. The composition was laminated using a melt extruder having a T-die to form a 30 μm-thick backside resin coating layer.

Next, after the other surface of the sheet-shaped substrate was subjected to corona discharge treatment, a linear low-density polyethylene resin (density 0.926, melt index 16 g / 10 g
min) 50 parts by weight, low density polyethylene resin (density 0.9
18, melt index 4 g / 10 min) 50 parts by weight,
And a polyolefin resin composition obtained by adding and mixing and dispersing a small amount of zinc stearate and an antioxidant to 13 parts by weight of anatase type titanium dioxide, and laminating using a melt extruder having a T-die to form a surface having a thickness of 35 μm. A side resin coating layer was formed to produce a photographic printing paper support.

Using the obtained photographic printing paper support, the fog density was measured in the same manner as in Example 1. Table 2 shows the results
Shown in

Example 6 A base paper was made in the same manner as in Example 1, and a carboxyl-modified polyvinyl alcohol (manufactured by Nippon Gohsei, trademark: T-330H) and sodium chloride were mixed in the base paper at a ratio of 5: 2. The 5% -concentration size press application liquid was applied and dried so that the solid application amount was 2.5 g / m ² , followed by size press processing, followed by machine calendering to obtain a basis weight. 170 g / m ² , tension 1.0 g / cm ³ ,
A sheet-like substrate made of paper having a water content of 8.0% was produced.

Next, after forming a resin coating layer on the front side and the back side on both sides of the sheet-like substrate in the same manner as in Example 8, the surface of the resin coating layer on the front side was subjected to a corona discharge treatment to obtain the following composition. The 5% concentration of the coating solution for forming a sub-coat layer is coated with a gravure coater to a solid content of 1.0%.
g / m ^2, and dried at 100 ° C. for 1 minute using a hot-air drier to form a sub-coat layer, thereby producing a photographic printing paper support.

[0056] subcoat layer forming coating liquid composition Ingredient amount photographic gelatin 70 parts by weight (trademark: P-100, Miyagi Kagaku) 30 parts by weight of gelatin crosslinking agent 1 part by weight of magnesium hydroxide (trademark: HDU, mutual 1 part by weight of surfactant (trade name: Emar E27C, manufactured by Kao)

Using the obtained photographic printing paper support, the fog density was measured in the same manner as in Example 1. Table 2 shows the results
Shown in

Example 7 A sheet-like substrate was produced in the same manner as in Example 5, and a front-side and a back-side resin coating layer were formed on both sides of the sheet-like substrate. Next, a sub-coat layer was formed on the surface of the front-side resin coating layer in the same manner as in Example 10 to prepare a photographic printing paper support. Using the obtained photographic printing paper support, the fog density was measured in the same manner as in Example 1. Table 2 shows the results
Shown in

Example 8 A sheet-like substrate was prepared in the same manner as in Example 6, and a front-side and a back-side resin coating layer were formed on both sides of the sheet-like substrate. Next, after applying a corona discharge treatment to the surface of the resin coating layer on the back side, a 3% concentration coating liquid for forming a back coat layer having the following composition was applied to a solid coating amount of 1% using a bar coater. It was applied so as to be 0 g / m ² and dried at 100 ° C. for 2 minutes with a hot air drier to prepare a photographic printing paper support.

[0060] the back coat layer forming coating liquid composition Ingredient weight styrene - butadiene copolymer resin 50 parts by weight (trademark: LX-405-4C, Nippon Zeon) 10 parts by weight of sodium polystyrene sulfonate (trademark: Chemistat CS-6120, manufactured by Sanyo Kasei) 40 parts by weight of calcium carbonate (trademark: Softon 2200, manufactured by Bihoku Powder Chemical Industry) 5 parts by weight of alumina (trademark: alumina sol 200, manufactured by Nissan Chemical) 30 parts by weight of magnesium hydroxide

Using the obtained support for photographic printing paper, the fog density was measured in the same manner as in Example 1. Table 2 shows the results
Shown in

Comparative Example 6 A sheet-like substrate was prepared in the same manner as in Example 6, and then a resin coating layer on the front side and the back side was formed on both surfaces of the sheet-like substrate in the same manner as in Example 8. A paper support was prepared. Example 1 was prepared using the obtained photographic printing paper support.
The fog density was measured in the same manner as described above. Table 2 shows the results.

[0063]

[Table 2]

As is clear from Tables 1 and 2, the photographic printing papers produced using the photographic printing paper supports of Examples 1 to 8 according to the present invention have a sufficiently low fog density and are practically usable. There was no problem. However, Comparative Examples 1 to 6
In the photographic printing paper obtained from the photographic printing paper support containing no magnesium hydroxide, the occurrence of fog higher than that according to the present invention was observed.

[0065]

The photographic printing paper produced by using the photographic printing paper support of the present invention is less practically fogged even when developed after being stored for a long period of time, and is extremely useful in practice.

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-61-86747 (JP, A) JP-A-60-11841 (JP, A) JP-A-56-43637 (JP, A) JP-A-1- 257845 (JP, A) JP-A-3-73944 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) G03C 1/775 G03C 1/76

Claims (2)

(57) [Claims] As claimed in claim 1] component, and the sheet-shaped substrate is provided on both sides of the sheet substrate, and the surface side and back surface side resin coating layer containing a polyolefin resin as a main component, the surface-side resin coating layer Formed on top and highly film-forming
A sub- coat layer containing a molecular material as a main component , and a film-forming property formed on the backside resin coating layer,
A back coat layer containing a molecular material as a main component, wherein at least one of the constituent elements contains magnesium hydroxide . 2. The method according to claim 1, wherein the sheet-like substrate is made of magnesium hydroxide.
Having a size press coating layer containing a beam, photographic printing paper support of claim 1.