JP2871895B2 - Support for photosensitive material - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a support for a resin-coated paper type photosensitive material in which a paper base mainly composed of natural pulp (hereinafter referred to as "base paper") is coated with a resin capable of forming a film, preferably a polyolefin resin. More specifically, the present invention relates to a resin-coated paper-type photosensitive material support having good photographic suitability for a silver halide photosensitive layer.

[0002]

2. Description of the Related Art As a support for a photosensitive material, a resin-coated paper-type support for a photosensitive material in which at least one surface of a substrate is coated with a resin capable of forming a film is well known. For example, Japanese Patent Publication No. 55-12584 discloses a technique for a support for a photosensitive material in which a base paper is coated with a resin capable of forming a film, preferably a polyolefin resin. U.S. Pat. No. 3,501,298 discloses a technique for a support for a photosensitive material in which both sides of a base paper are coated with a polyolefin resin. Further, since being rapid photographic development processing method of a silver halide photographic light-sensitive material is applied, the support for the photosensitive material both sides of a base paper coated with polyethylene resin, are mainly commercialized as for photographic printing paper If necessary, the resin layer on one image forming side usually contains a titanium dioxide pigment in order to impart sharpness.

However, a support for a resin-coated paper-type light-sensitive material in which a base paper mainly composed of natural pulp is coated with a resin capable of forming a film is still important in the point of photographic suitability for a silver halide photosensitive layer. Had a serious problem.

That is, when a silver halide photosensitive material using a resin-coated paper in which a base paper mainly composed of natural pulp is coated with a resin capable of forming a film as a support is stored after its production,
When stored for a long period of time, especially when stored under high temperature and high humidity, the silver halide of the light-sensitive material is fogged into spots, and the unexposed portions can be developed into spots during development processing. And the sensitivity of the light-sensitive material is reduced or increased in a spot-like manner. For example, in the case of a certain type of black-and-white silver halide photographic paper using the resin-coated paper as a support, fog is generated in a spot-like manner on a white background. The spot-like fog sometimes reaches as much as 20 mm in diameter, and the photographic paper has no commercial value at all. Further, in the case of a silver halide diffusion transfer type photosensitive material having the resin-coated paper as a support for the silver halide negative photosensitive layer, fog is generated in the silver halide photosensitive layer on the negative side in spots. As a result, the image density on the positive side is reduced in a spot-like manner, and the silver image is hardly formed in a spot-like manner, and the commercial value is completely lost. Further, in the case of a certain type of multilayer silver halide color photographic paper, in which a yellow coloring layer, a magenta coloring layer and a cyan coloring layer are sequentially arranged adjacent to the support using the resin-coated paper as a support, As fog occurs,
In particular, there has been a problem that the yellow and magenta coloring layers cause a decrease in sensitivity in the form of spots, and the color balance of the image is lost in the form of spots, and the commercial value of photographic paper is lost. Hereinafter, these phenomena will be collectively referred to as spot defects.

Until now, various stabilizers or antifoggants have been proposed for preventing a change in photographic characteristics during storage of a silver halide light-sensitive material. However, even if various stabilizers or antifoggants are contained in the constituent layers of the silver halide light-sensitive material having a resin-coated paper as a support, considerable photographic adverse effects such as a decrease in sensitivity and a soft tone are produced. In addition, the spot failure could hardly be prevented.

There are also several proposals relating to the photographic properties of a support for a photosensitive material. The JP 54-98 8 4 No., hydrin b <br/> carboxymethyl - substituted - were coated base paper with a polyolefin resin containing the triazolopyrimidine compounds, antifoggants of supporting resin-coated paper type photosensitive material Although a body has been proposed, it has been extremely insufficient to prevent spot failure of a silver halide light-sensitive material having the support. Regarding photographic paper, JP-A-52-65423 and JP-B-58-43730 propose to remove adverse effects on photographic properties due to decomposition of cationic electrolytes and additives for paper, respectively. The spot failure cannot be prevented at all with the silver halide photosensitive material using the resin-coated paper made of the above photographic paper as a support, and the spot failure is caused by a mechanism completely different from the mechanism described in these specifications. It became clear to do. Also, Japanese Patent Application Laid-Open Nos. 2-96741, 2-99689 and 2-99693 propose techniques for improving the photographic properties of unbleached kraft paper. According to them, the photographic properties of bleached kraft paper are good, but the photographic properties of unbleached kraft paper are poor, because propylene oxide and / or silicon, which are antifoaming components used in the unbleached stage, remain. And defoamer containing those components and cold water extraction.
It has been proposed to improve the photographic properties of unbleached kraft paper by specifying H. However, a spot failure cannot be prevented at all with a silver halide photosensitive material using a resin-coated paper made of a base paper containing bleached natural pulp as a main component to which the technique is applied. It has been found to occur by a mechanism completely different from that described in the book. Furthermore, in Japanese Patent Publication No. 58-43732, a resin-coated paper consisting of a base paper mainly composed of natural pulp bleached using an alkaline peroxide,
Although a technique for improving the storability of silver halide photographic materials has been proposed, the use of the resin-coated paper did not sufficiently prevent spot defects. Still further,
No. 8575 proposes a technique for preventing fogging and spots of silver halide photographic material by using photographic paper using wood pulp obtained by the oxygen pulping method, but a resin coating using the photographic paper as a substrate is proposed. Even with the use of paper, preventing spot defects was still insufficient.

As described above, the technique for improving the spot failure of a silver halide photosensitive material using a resin-coated paper in which a base paper containing natural pulp as a main component is coated with a resin capable of forming a film, and a technique for improving the spot failure are described. The generation mechanism or cause is
It is not known at all, and it was not possible to improve the spot failure at all using a conventionally known technique.

[0008]

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a base paper containing natural pulp as a main component, in which the tendency of spot defects to the silver halide light-sensitive layer is significantly suppressed. An object of the present invention is to provide a support for a photosensitive material coated with a certain resin. Other objects of the present invention will become apparent from the following description.

[0009]

In order to solve the above-mentioned problems, the inventors of the present invention have made intensive studies and as a result, have found that a base paper mainly composed of natural pulp is coated with a resin capable of forming a film. In the material support, a part or all of the natural pulp constituting the base paper is a natural kraft pulp, and as the natural kraft pulp, the presence of an antifoaming agent or a defoamer in an unbleached stage after cooking by the Kraft method. The natural kraft pulp has been subjected to an oxygen delignification treatment before and after the washing treatment and a bleaching treatment in a subsequent bleaching step, and the discoloration of the natural kraft pulp by a silver discoloration reaction as defined herein. It has been found that the object of the present invention is achieved by using natural kraft pulp in which the number of generated kraft pulp is 20 or less per A-4. The number of discoloration generated by the silver discoloration reaction referred to in the present specification means that a natural kraft pulp sample (basis weight: 7 as a sample condition) was applied to the silver surface of a silver plate prepared based on Tappi Standard T444.
50 g / m ² ± 150 g / m ² , absolute dry water content; 20% by weight ± 5
% By weight, pH: 6.0 to 7.5 as the pH of the pulp suspension when prepared based on Tappi Standard T205.
), Sealed in a black plastic bag, and heated at a temperature of 50 ° C ± 1 ° C and a relative humidity of 81% ± 2% for 50 hours under a load of 2.5 kg per A-4. After the treatment, the number of occurrences of silver discoloration reaction on the silver surface was measured.

According to the study of the present inventors, when natural kraft pulp is subjected to a washing treatment in the presence of an antifoaming agent or an antifoaming agent at the unbleached stage after cooking, it is caused by a black liquor component or a modified black liquor component. A water-insoluble or poorly water-soluble silver discoloration reaction generating substance is occluded by the action of an antifoaming agent or an antifoaming agent,
And remain locally, surprisingly, the silver discoloration reaction-generating material resists attack by an oxidizing agent or an alkaline agent in a subsequent bleaching step and remains in bleached natural kraft pulp;
Furthermore, the bleached natural kraft pulp is beaten and locally left on the base paper, and the silver discoloration reaction generating substance is found to cause spot failure. Is subjected to a washing treatment in the presence of an antifoaming agent or a defoaming agent, and is subjected to oxygen delignification treatment before and after the washing treatment, and is subjected to a bleaching treatment in a subsequent bleaching step, and has a small amount of a silver discoloration reaction generating substance. The inventors have found that spot defects can be improved by using natural kraft pulp, and the present invention has been accomplished.

As the natural kraft pulp used in the practice of the present invention, wood kraft pulp of softwood kraft pulp, hardwood kraft pulp, and softwood mixed kraft pulp is advantageously used. As for the wood kraft pulp, wood chips are cooked under pressure with a mixture containing sodium hydroxide and sodium sulfide as chemical components, so-called cooking liquor, so-called digestion, and lignin is removed.
Thereafter, in the presence of an antifoaming agent or a defoaming agent, the pulp fiber and the digestion liquor, so-called black liquor, are separated and washed, subjected to oxygen delignification treatment, and then bleached, and are preferably used. As chemical components in the cooking liquor, in addition to sodium hydroxide and sodium sulfide, salts such as sodium carbonate, sodium sulfate, slaked lime and calcium carbonate, and cooking aids such as sodium borohydride and anthraquinone compounds are also contained. You may. Further, it may be produced by various digestion methods such as polysulfide digestion, batch digestion, continuous digestion, etc., or may be produced by various sulfurization degrees and kappa numbers.

The base paper used in the practice of the present invention is composed of natural pulp as a main component and part or all of natural kraft pulp, preferably wood kraft pulp. If necessary, natural pulp other than natural kraft pulp, synthetic fiber or synthetic pulp may be used. As the pulp used in combination with the natural kraft pulp, natural pulp is preferable, and wood sulphite pulp of softwood sulphite pulp, hardwood sulphite pulp, and mixed sulphite pulp of softwood sulphate is particularly preferable. Also, wood soda pulp, wood dissolving pulp, or the like can be used.

Various kinds of defoaming agents or defoaming agents can be used in the practice of the present invention. For example, JP-A-54-59404, JP-A-58-220896, JP-A-61-245391
No. 3,087,038, U.S. Pat.No. 3,923,638, U.S. Pat.No. 4,107,073 or the like, or higher fatty acid alcohol ester compounds, mineral oils or liquid hydrocarbon oils, silicone oils and the like. Can be used. Among them, an aqueous-based or oil-based antifoaming agent or foam inhibitor containing a mineral oil or a liquid hydrocarbon oil as a component is particularly preferable in terms of antifoaming or foam suppressing properties. The defoaming agent or the defoaming agent may contain components such as hydrophobic silica, ethylene higher alkylamide, and silicone oil. As a method of causing these defoamers or defoamers to be present during the washing process of unbleached kraft pulp, an antifoaming agent or defoamer is added to the slurry or thickener of unbleached kraft pulp at any stage during the washing process. It is preferred to add.

The natural kraft pulp, preferably wood kraft pulp, used in the practice of the present invention is subjected to a washing treatment after digestion, followed by an oxygen delignification treatment, preferably a further washing treatment and then a bleaching treatment. Are advantageously used. The conditions for the oxygen delignification treatment include a delignification degree of 20 at the oxygen delignification stage.
It is preferably set to be 70%, preferably 40% to 50%. In addition, the oxygen delignification treatment is carried out in the presence of at least oxygen and an alkali, and preferably an agent for preventing a decrease in the degree of polymerization of pulp. As the oxygen used for the oxygen delignification treatment, those supplied from an oxygen cylinder, those mainly containing oxygen produced from air by an oxygen-enriched film, and the like are advantageously used. In the oxygen delignification treatment, oxygen alone may be used, or an oxygen-based oxidizing agent such as hydrogen peroxide may be used in combination, or ozone, nitrogen oxide or the like may be used. The alkali used in the oxygen delignification process, sodium hydroxide, sodium carbonate, oxidized white liquor, although an alkali solution such as oxide green liquor can be used, preferably using an acid of white liquor. Examples of the pulp polymerization degree lowering inhibitor preferably used for oxygen delignification treatment include magnesium carbonate, magnesium sulfate, calcium chloride and the like. Specific conditions of the oxygen delignification treatment can be performed under various treatment conditions. For example, specifically, the pulp concentration is in the range of 5 wt% to 35 wt%, preferably 10 wt.
wt% to 20 wt%, the amount of oxygen added is 0.2 wt% to 4 wt%, preferably 0.5 wt% to 2 wt%, preferably 0.5 wt% to 2 wt%, based on the absolute dry weight of the unbleached pulp. Is 0.1 in terms of caustic soda per absolute dry weight of unbleached pulp.
2 wt% to 7 wt%, preferably 0.5 wt% to 3 wt%
Range. The treatment temperature of the oxygen delignification treatment is in the range of 50 ° C. to 150 ° C., and the treatment time is
A range from 10 minutes to 180 minutes is preferred. The addition amount of the polymerization degree lowering inhibitor of the pulp used as needed is preferably in the range of 0.05 wt% to 1 wt% based on the absolute dry weight of the unbleached pulp.

The natural kraft pulp, preferably wood kraft pulp, used in the practice of the present invention has been subjected to a bleaching treatment in the cooking, washing, oxygen delignification and bleaching stages after washing. The bleaching treatment is preferably a chlorination treatment, an alkali treatment or extraction or purification, a hypochlorite bleaching treatment, a chlorine dioxide bleaching treatment and a multi-stage bleaching treatment thereof, and if necessary, furthermore, Japanese Patent Publication No. 58-4
Alkaline peroxide bleaching treatment described or exemplified in No. 3732, or reduction bleaching treatment with hydrosulfite, sodium borohydride or the like may be performed. In addition,
As used herein, the bleaching step refers to a bleaching step after the chlorination step.

As a preferred multistage bleaching method for wood kraft pulp which is advantageously used in the practice of the present invention, the first stage is a chlorination stage (hereinafter abbreviated as C), and the second stage is an alkali treatment or extraction stage (hereinafter referred to as an extraction stage). The third stage is a hypochlorite bleaching stage (hereinafter abbreviated as a symbol H) or a chlorine dioxide bleaching stage (hereinafter abbreviated as a symbol D). The oxide bleaching step (hereinafter abbreviated as P) is advantageously carried out in the fourth and subsequent steps. For example, "CEHDED", "CE
HDPD "," CEHEDDP "," CEHED ",
"CEHPD", "CEHEDP", "CEHEH",
"CEHEHP", "CEHPHP", "CEDE
D "and" CEDEDP "are useful.

As a chemical for bleaching wood kraft pulp that is advantageously used in the practice of the present invention, chlorine gas or chlorine water is used for chlorine bleaching. Further, chlorine dioxide may be used in combination. It is advantageous to use caustic soda for the alkali treatment or extraction, but calcium hydroxide, ammonia and the like and mixtures thereof can be used.
For hypochlorite bleaching, bleached powder made by applying chlorine to slaked lime in the form of solid powder, especially hypochlorous acid bleaching solution prepared industrially by blowing chlorine into lime milk or dilute caustic soda solution , So-called calcium-hypo bleach, sodium-
Hypo bleach is advantageously used. For chlorine dioxide bleaching,
Mathison method, New Matheson method, Elst method, C.I. I. Chlorine dioxide prepared by a sulfurous acid method such as the P method, a kissing method, a Nisso method, or a hydrochloric acid method such as the Solvay method is advantageously used. For peroxide peroxide bleaching in alkaline, the peroxides include hydrogen peroxide, sodium peroxide, peroxide bleaching solution (hydrogen peroxide, caustic soda, sodium silicate and, if necessary, Inorganic or organic peroxides such as peracetic acid, t-butyl hydroperoxide and the like and mixtures thereof are advantageously used, and alkalis include caustic soda, potassium hydroxide, Alkali hydroxides or alkaline earth hydroxides, such as aqueous ammonia, magnesium hydroxide and calcium hydroxide, and mixtures thereof are advantageously used. The bleaching can be performed under various conditions, such as those described in "Pulping and Bleaching" (published on January 27, 1968), edited by Japan Society of Paper and Pulp Technology, and Japanese Patent Publication No. 58-43732. .

The natural kraft pulp, preferably the wood kraft pulp, used in the practice of the present invention has A-4 as the number of discoloration generated by the silver discoloration reaction defined herein.
20 or less per A-4, preferably 10 or less per A-4, more preferably 5 or less per A-4, and 2 or less (including 0) per A-4 Is most preferred. Natural kraft pulp, preferably wood kraft pulp, in which the number of discoloration generated by silver discoloration reaction is 20 or less per A-4, specifically, is subjected to oxygen delignification treatment, and by using, for example, the following method, It has been clarified by the inventors of the present invention that it is preferably obtained by using two or more, more preferably three or more, of the following methods in combination.

(1) The amount of the defoamer used is defined as its component (in the case of an aqueous base defoamer, the component excluding water) per unbleached pulp (hereinafter referred to as absolute dry weight unless otherwise specified). As) 0.1-1.5 kg, preferably 0.1-1.0 kg,
More preferably, it is in the range of 0.1 to 0.75 kg.

(2) Before the bleaching step, the pH of the unbleached kraft pulp thickener is adjusted to 6.0 or more, preferably 6.5 or more, more preferably 7.0 or more. The pH of the unbleached kraft pulp thickener is defined as follows: 50 g of unbleached kraft pulp thickener is added with 300 g of distilled water, stirred well for 1 hour, and then subjected to a liquid temperature of 25 ° C. ± by a pH meter.
It was measured at 1 ° C.

(3) The electric conductivity of the unbleached kraft pulp thickener before the bleaching stage is at least 50 μmho / cm.
It is preferably at least 100 μmho / cm, more preferably 1 μmho / cm.
It should be 50 μmho / cm or more. The electric conductivity of the unbleached kraft pulp thickener was defined as the following: 50 g of unbleached kraft pulp thickener, 300 g of distilled water added, and the mixture was stirred well for 1 hour.
It was measured in.

(4) The calcium content in the unbleached kraft pulp before the bleaching stage is minimized. Specifically, unbleached kraft pulp thickener before entering the bleaching stage
When the paper is composed of, the calcium content in the paper is 5
000 ppm or less, preferably 4000 ppm or less, more preferably 3000 ppm or less. The preparation of paper with unbleached kraft pulp thickener was carried out in accordance with Tappi Standard T-205 except that deionized water was used as the water to be used. It was measured by the X-ray method.

(5) The calcium content in the unbleached white water is minimized. To do so, the calcium content from the cooking step is reduced. For example, selection of an appropriate tree species, improvement of the removal efficiency of insoluble calcium salts present in white water such as calcium hydroxide and calcium carbonate by filtration, chelating agent to unbleached white water such as EDTA-sodium salt, etc. It is preferable to carry out the addition or the like.

(6) The pH of the kraft pulp slurry in the chlorine stage is not more than 2.5, preferably 2.0.
In the following, it is more preferably set to 1.5 or less.

(7) The bleached kraft pulp before the papermaking process is cleaned using a cleaner, preferably a hydrocyclone type cleaner. The final reject rate in the cleaner is 0.02% by weight or more, preferably 0.05% by weight or more, and more preferably 0.1% by weight or more based on the absolutely dry pulp.

The base paper used in the practice of the present invention may contain various additives during preparation of the stock slurry. Examples of the sizing agent include fatty acid metal salts and / or fatty acids, alkyl ketene dimer emulsions described or exemplified in JP-B-62-7534, epoxidized higher fatty acid amides, alkenyl or alkyl succinic anhydride emulsions, and rosin derivatives. As a paper strength enhancer, anionic, cationic or amphoteric polyacrylamide, polyvinyl alcohol, cationized starch, vegetable galactomannan, etc., as a wet strength agent, polyamine polyamide epichlorohydrin resin, etc., as a filler, clay,
Kaolin, calcium carbonate, titanium oxide, etc., as a fixing agent, aluminum chloride, water-soluble aluminum salts such as bansulfate, etc., as a pH adjusting agent, caustic soda, sodium carbonate, sulfuric acid, etc., other JP-A-63-204251, JP Hei 1-26
It is advantageous to incorporate color pigments, coloring dyes, fluorescent whitening agents and the like described or exemplified in, for example, No. 6537 in an appropriate combination.

In the base paper used in the practice of the present invention, various water-soluble polymers, antistatic agents and additives can be contained by spraying, size press or tab size press. Examples of water-soluble polymers include starch-based polymers, polyvinyl alcohol-based polymers, gelatin-based polymers, polyacrylamide-based polymers, and cellulose-based polymers described and exemplified in JP-A 1-266537, and sodium chloride, potassium chloride, and the like as antistatic agents. Petroleum resin emulsions as latex and emulsions, such as alkali metal salts, alkaline earth metal salts such as calcium chloride and barium chloride, colloidal metal oxides such as colloidal silica, organic antistatic agents such as polystyrene sulfonate , Styrene-acrylic acid-
Acrylic ester copolymer, styrene-acrylic acid-
Butadiene copolymer, ethylene-vinyl acetate copolymer,
Latexes such as styrene-maleic acid-acrylic acid ester copolymers, as pigments, clay, kaolin, talc, barium sulfate, titanium oxide, etc., as pH regulators, hydrochloric acid, phosphoric acid, citric acid, caustic soda, etc. It is advantageous to incorporate additives such as coloring pigments, coloring dyes and fluorescent brighteners in an appropriate combination.

The base paper used in the practice of the present invention includes:
Beck smoothness specified by JIS P8119 is 1
Those having a smooth surface of at least 00 seconds are preferable, and those having a smooth surface of at least 200 seconds are more preferable. As a method for producing a base paper having a Beck smoothness of 100 seconds or more, generally, hardwood pulp that is short fiber and has high smoothness is often used and beaten by a beater so as to reduce the long fiber content as much as possible. Specifically, the beating of the pulp has a fiber length of 42 mesh residue of 20 to 45% and a freeness of 2 after the beating.
It is preferable to set it to 00 to 350 CSF.
Next, regarding the stock chiller to which the internal chemicals are added, JP-A-58-37642, JP-A-61-260240, and JP-A-61-28476.
Paper making is performed by using an appropriate paper making method as described or exemplified in No. 2, etc. so that a uniform formation can be obtained with a commonly used paper machine such as a fourdrinier paper machine or a round net paper machine. Thereafter, a calendar process is performed using a machine calendar, a super calendar, a thermal calendar or the like, and a base paper having a Beck smoothness of 100 seconds or more can be manufactured. The thickness of the base paper is not particularly limited.
ones g / m ² ~250g / m ² is preferred.

As the resin capable of forming a film used in the practice of the present invention, a thermoplastic resin such as a polyolefin resin, a polycarbonate resin, a polyester resin, and a polyamide resin is preferable. And a polyolefin resin is more preferred. Also,
It may be coated with an electron beam curable resin described or exemplified in JP-B-60-17104.

Examples of the polyolefin resin preferably used in the practice of the present invention include homopolymers such as polyethylene, polypropylene, polybutene and polypentene, and copolymers composed of two or more α-olefins such as an ethylene-butylene copolymer. The polyethylene resin is particularly preferred from the viewpoints of melt extrusion coating properties and adhesion to the base paper. 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 having various densities, a melt flow rate (hereinafter simply referred to as MFR), a molecular weight, and a molecular weight distribution can be used, and usually, the density is 0.90 to 0.97 g / cm.
³ , MFR 0.1 g / 10 min-40 g / 10 min, preferably MFR 0.3 g / 10 min-30 g / 10 min, molecular weight 20,000-2
Those in the range of 50,000 can be advantageously used alone or as a mixture. When the resin has a multi-layer structure, the outermost layer resin may be, for example, MFR 5 g / 10 min to 20 g / 10 min, and the lower layer resin may be, for example, MFR 2 g / 10 min to 10 g / 10 min. Resins having the properties and constitutions described above can also be used.

Various additives can be contained in the resin layer of the support for a light-sensitive material in the present invention. JP-B-60-3430, JP-B-63-11655, JP-B1-38291
No. 1-38292, JP-A-1-105245 and the like or white pigments such as titanium oxide, zinc oxide, talc, calcium carbonate, etc., fatty acid amides such as stearamide, arachidic amide, stearic acid Fatty acid metal salts such as zinc, calcium stearate, aluminum stearate, magnesium stearate, zinc palmitate, zinc myristate and calcium palmitate;
Hindered pheno-phenol described or exemplified in 1-105245
, Pigments and dyes such as cobalt blue, ultramarine blue, celian blue, phthalocyanine blue, etc., cobalt violet, fast violet, manganese violet, etc. Various additives such as magenta pigments and dyes, and fluorescent whitening agents and ultraviolet absorbers described or exemplified in JP-A-2-254440 can be incorporated in an appropriate combination. These additives are preferably contained as a masterbatch or compound of a resin capable of forming a film. When the resin capable of forming a film is a thermoplastic resin, preferably a polyethylene resin, the resin layer is preferably produced by a melt extrusion coating method in which a molten resin is coated on a running base paper. . Before the resin is coated on the base paper, the base paper is preferably subjected to an activation treatment such as a corona discharge treatment or a flame treatment.

The photosensitive layer side surface of the support for a photosensitive material according to the present invention has a glossy surface or a fine roughness described in JP-B-62-19732 which does not affect the gloss of the surface of the photosensitive material. The surface has a matte surface, a silk surface or the like, the back surface is usually a matte surface, and the front surface or both front and back surfaces can be subjected to activation treatment such as corona discharge treatment or flame treatment as required. Further, after the activation treatment, JP-A-61-84643
Subtraction processing as described in the item can be performed. Also, the thickness of the front and back resin layers is not particularly limited,
Generally, those having a thickness of about 10 μ to 50 μ are advantageous.

Various types of back coat layers can be coated on the support for a light-sensitive material of the present invention to prevent static charge and curl. The back coat layer includes JP-B-52-18020, JP-B-57-9059, and JP-B-57-53940.
No., JP-B-58-56859, JP-A-59-214849, JP-A-58
An inorganic antistatic agent, an organic antistatic agent, a hydrophilic binder, a latex, a curing agent, a pigment, a surfactant and the like described or exemplified in JP-184144A can be incorporated in an appropriate combination.

The support for the photosensitive material 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, typesetting photographic paper, copy photographic paper, and reversal photographic material. It can be used for various uses such as a silver salt diffusion transfer method for negatives and printing materials. For example, a silver chloride, silver bromide, silver chlorobromide, silver iodobromide, silver chloroiodobromide emulsion layer can be provided. The silver halide photographic emulsion layer may contain a color coupler to provide a multilayer silver halide color photographic constituting layer. Further, a photosensitive layer for silver salt diffusion transfer method can be provided. As a binder for these photographic constituent layers, in addition to ordinary gelatin, hydrophilic polymer substances such as polyvinylpyrrolidone, polyvinyl alcohol, and sulfate compounds of polysaccharides can be used. Further, the above-mentioned photographic constituent layer can contain various additives.
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 alkylbenzene sulfonates and sulfosuccinate salts, etc. 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 appropriately combined during generation and dispersion of silver halide.

The light-sensitive material according to the present invention can be used in accordance with the light-sensitive material described in "Photosensitive Material and Handling Method" (Kyoritsu Shuppan, Goro Miyamoto, Photographic Technology Course 2).
Processing such as development, stopping, fixing, bleaching, and stabilization are performed. In particular, a multilayer silver halide color photographic light-sensitive material which is subjected to one-bath bleach-fixing processing after color development is CD-III or 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 a color developing solution of any principal agent. The developer containing such a main agent may contain a development accelerator such as benzyl alcohol, thallium salt, and phenidone.
Processing can also be carried out with a developer substantially free of benzyl alcohol. A useful one-bath bleach-fixing solution is a solution of a metal salt of aminopolycarboxylic acid (for example, a ferric complex salt such as ethylenediaminetetraacetic acid or propylenediaminetetraacetic acid). As a fixing agent, sodium thiosulfate is used. And ammonium thiosulfate are useful. Various additives can be contained in such a one-bath bleach-fix solution. For example, a desilvering accelerator (e.g., mercaptocarboxylic acid described in U.S. Pat. No. 3,512,979, Bergi-Patent No. 682,426)
, A stain inhibitor, a pH regulator or a pH buffer, a hardener (for example,
Various compounds such as magnesium sulfate, aluminum sulfate, potassium alum and the like can be contained in combination. Such a single-bath bleach-fixing solution can be used at various pHs, but a useful pH range is pH 6.
0 to 8.0.

[0036]

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

Example 1 In the hardwood kraft pulp manufacturing process, the unbleached kraft pulp after the digestion was subjected to a washing treatment in the first stage washing process, and then subjected to oxygen delignification treatment under the following conditions. Washing was performed in the washing step, and bleaching was performed in the subsequent steps according to the “CEHDPD” method. On the other hand, in the production process of the hardwood pulp for comparison, the oxygen delignification treatment was omitted. Conditions for the oxygen delignification treatment include:
The pulp concentration is 15% by weight as the dry weight of the unbleached pulp, the added amounts of caustic soda and oxygen are 1.5% by weight and 1.0% by weight, respectively, based on the dry weight of the unbleached pulp, the processing temperature and the processing time are 110 ° C and 45 minutes, respectively. Met. In addition, as a process condition other than the oxygen delignification process of the hardwood kraft pulp, the total amount of the oil-based defoaming agent containing mineral oil as a component in the washing stage of the unbleached kraft pulp is the absolute dry weight of the unbleached pulp. 0.7 kg, 1.0 kg, 1.5 per ton
kg or 2.0 kg, the electric conductivity of the unbleached thickener as defined in the specification is 100 μmho / cm, and the final rejection rate of the hydrocyclone type cleaner is 0.01 wt% with respect to the dry pulp. .02 wt%, 0.05 wt% or 0.1 wt%, adjusted to the combinations shown in Table 1,
The other process conditions were appropriately adjusted to obtain hardwood bleached kraft pulp in which the number of discolorations generated by the silver discoloration reaction defined in the specification was as shown in Table 1.

Next, each of the pulp was Canadian
Beat it to 320 ml of standard freeness, and further add 3 parts by weight of a cationized starch to 100 parts by weight of pulp.
0.2 parts by weight of anionic polyacrylamide, alkyl ketene dimer emulsion (as ketene dimer)
4 parts by weight and 0.4 parts by weight of a polyaminopolyamide epichlorohydrin resin were added to produce a paper having a basis weight of 100 g / m ² . The obtained wet paper is dried at 110 ° C., and subsequently 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. 25g /
m ² impregnated, dried with hot air at 110 ° C, and further with a linear pressure of 90k
After supercalendering at g / cm, both surfaces were subjected to corona discharge treatment to produce a base paper for a support for a photosensitive material.

Next, a low-density polyethylene resin (density 0.92 g / cm ³ , MFR = 8.5 g / 10 min) was placed on the surface of the base paper 47.
5% by weight, 50% by weight of anatase type titanium dioxide pigment surface-treated with hydrous aluminum hydroxide (0.75% by weight as Al ₂ O ₃ relative to titanium dioxide) and 2.5% by weight of zinc stearate Master batch of titanium pigment 20 parts by weight, low-density polyethylene resin (density 0.92 g / cm ³ , MFR = 4.5 g / 10 min) 65 parts by weight and high-density polyethylene resin (density 0.97 g / cm ³ , MFR) =
(7.0 g / 10 min) A resin composition consisting of 15 parts by weight was melt-extruded and coated at a resin temperature of 330 ° C. to a thickness of 13 μm. Before the application of the resin layer on the surface of the base paper, the low-density polyethylene resin (density: 0.92 g / cm ³ , MFR: 2 g / 10 min), 15 parts by weight, was applied to the opposite side (back side) of the base paper. Density polyethylene resin (density 0.96 g / cm ³ , MFR 20 g / 10
Min) a resin composition consisting of 85 parts by weight at a resin temperature of 330 ° C.
Was melt-extruded and coated to the same thickness as the surface. At this time, the surface of the resin layer containing the titanium dioxide pigment of the thus prepared support for a light-sensitive material was processed into a slightly rough surface, and the surface quality of the resin layer on the back was processed into a matte surface such as paper.

Thereafter, a back coat layer having a composition of colloidal silica: styrene acrylic latex = 1: 1 as a dry weight after the corona discharge treatment was applied to the back surface of the support for a photosensitive material at a rate of 0.4 g / m ² . . Next, the emulsion layer and its protective layer were provided on the front side resin surface containing the titanium dioxide pigment of the support for a photosensitive material after corona discharge treatment to obtain a black-and-white photographic printing paper. The emulsion layer generates and dispersed silver halide grains of 19.2g content with silver nitrate in a gelatin 14.4g in the presence of hexachloro iridium (III) potassium <br/> um 1.2 × 10 ^-5 g substantially [1,0 in combination sensitized by sulfur sensitization and gold sensitization optimal sensitivity of the average particle diameter of 0.6μ with ArBr / AgCl = 65/35 becomes halogen composition was prepared,
0] surface-containing neutral silver halide photographic emulsion, and further, in addition to gelatin necessary for film formation, appropriate amounts of stabilizers, sensitizing dyes, coating aids, hardeners, fluorescent brighteners, thickeners Agent, filter dye, etc., 2.2 g / m ^{2 in} silver nitrate and 4.
Coating was carried out with the protective layer at a coating weight corresponding to 4 g / m ² . The protective layer contains a coating aid and a hardener in addition to gelatin corresponding to ² g / m ² .

The coated and dried sample was 4% at 50 ° C. and 81%.
After storage for one day, black and white development was performed, and the number of spot fog was counted. Table 1 shows the obtained results.

[0042]

[Table 1]

As can be seen from Table 1, the samples of the present invention using wood kraft pulp treated with oxygen delignification and having a discoloration generation number of not more than 20 per A-4 by the silver discoloration reaction defined in the specification are as follows: The occurrence of spot fog is small, and the number of discoloration occurrences for wood kraft pulp is 1 per A-4.
It is well understood that the number is preferably 0 or less, and more preferably 5 or less per A-4.

Example 2 In the same manner as in Example 1 except that the wood kraft pulp used in Example 1 was subjected to an oxygen delignification treatment in the same manner as in Example 1, and the one manufactured under the following process conditions was used. Carried out.

In the hardwood kraft pulp production process, the total amount of the oil-based antifoaming agent containing mineral oil as a component in the washing stage of the unbleached kraft pulp is determined by the process of drying the unbleached pulp. 0.1kg per ton of weight,
0.7 kg, 1.0 kg, 1.5 kg or 2.0 kg, the electric conductivity of the unbleached thickener as defined in the specification is 45 μ
mho / cm, 100 μmho / cm or 150 μmho / cm, and the final rejection rate of the hydrocyclone cleaner is 0.01 wt%, 0.02 wt%, 0.05 wt% based on the dry pulp.
% Or 0.1 wt%, and adjusted to the combinations shown in Table 2 and the other process conditions as appropriate, and the number of discolorations generated by the silver discoloration reaction as defined in the specification was calculated as shown in Table 2.
As described above, hardwood bleached pulp was obtained. In addition,
If the amount of the antifoaming agent is less than 0.1 kg, the prevention of foaming is insufficient.

Table 2 shows the obtained results.

[0047]

[Table 2]

As can be seen from Table 2, the sample of the present invention using wood kraft pulp treated by oxygen delignification and having a discoloration generation number of not more than 20 per A-4 by the silver discoloration reaction defined in the specification is as follows: The occurrence of spot fog is small, and the number of discoloration occurrences for wood kraft pulp is 1 per A-4.
It is well understood that the number is preferably 0 or less, and more preferably 5 or less per A-4.

Example 3 In the same manner as in Example 1 except that the wood kraft pulp used in Example 1 was subjected to an oxygen delignification treatment in the same manner as in Example 1 and that manufactured under the following process conditions was used. Carried out.

In the hardwood kraft pulp manufacturing process, the total amount of the oil-based antifoaming agent containing mineral oil as a component in the washing stage of the unbleached kraft pulp is determined by the process of drying the unbleached pulp. 0.1kg per ton of weight,
0.7 kg, 1.0 kg, 1.5 kg or 2.0 kg, having a calcium content in the unbleached kraft pulp as defined herein of 3000 ppm, 4000 ppm or 55 ppm
Kraft pulp slurry at 00 ppm and chlorine stage
Is pH 1.5, pH 2.0 or pH 2.7, and is adjusted to the combination shown in Table 3, and the other process conditions are appropriately adjusted to generate discoloration by a silver discoloration reaction defined in the specification. The hardwood bleached pulp whose number is as shown in Table 3 was obtained.

Table 3 shows the obtained results.

[0052]

[Table 3]

As can be seen from Table 3, the samples of the present invention using wood kraft pulp treated with oxygen delignification and having a discoloration generation number of 20 or less per A-4 by the silver discoloration reaction defined in the specification are as follows: It is clear that the number of discoloration occurrence is preferably 10 or less per A-4, and more preferably 5 or less per A-4 as the wood kraft pulp.

Example 4 The number of discoloration generated by the silver discoloration reaction used in Example 2 was A-
Same as Example 1 except that wood pulp having 2.25 and 28 pieces per 4 was used, the basis weight of the base paper was 160 g / m ² , and the thickness of the resin layers on the front and back sides was 30 μm each. Thus, a support for a photosensitive material was obtained.

Next, the following emulsion layer and its protective layer were provided on the resin surface on the front side containing the titanium dioxide pigment of the support for the photosensitive material after the corona discharge treatment, to obtain a photographic paper. In the presence of the emulsion layer hexachloroiridate (III) potassium 1.0 × 10 ^-5 g, prepared product, dispersing the silver halide grains of the silver nitrate amount 9.6g min in gelatin 4.8 g AgBr /
And sulfur sensitization in the average optimal sensitivity of particle size 0.8μ with AgCl = 95/5 consisting halogen composition [1,0,0]
Neutral silver halide photographic emulsion composed of a mixed crystal of [1] and [1, 1, 1] planes. In addition to the yellow color coupler and gelatin necessary for film formation, an appropriate amount of stabilizer, sensitizing dyes, coating aids, hardening agents, contain a thickening agent such as, 0.6 g / m ² silver nitrate amount, the coating amount equivalent to 1.5 g / m ² gelatin, a multilayer coating with a protective layer Was. 1.5 g / m ^{2 of} protective layer
And a coating aid, a thickener, a hardener and the like in addition to gelatin corresponding to

The coated and dried sample was 4% at 50 ° C. and 81%.
After storage for days, color development was performed, and the number of spot fog was counted. Further, the sample after heating and preserving was subjected to uniform exposure so that the yellow-colored density became 0.4, and then color-developed,
The number of spots where desensitization was observed was counted.

As a result, in the sample of the present invention using wood kraft pulp in which the number of discoloration generated by the silver discoloration reaction was 2.25 per A-4, no spot failure was observed. On the other hand, in a sample other than the present invention using wood kraft pulp in which the number of discoloration generated by the silver discoloration reaction was 28 per A-4, several spots of fog and ten and several spots per A-4 were reduced. Feeling was recognized.

Example 5 The number of silver discoloration occurrences used in Example 2 was 2.25 per A-4.
Using 28 pieces of wood kraft pulp, 28 pieces of wood kraft pulp were prepared in the same manner as in Example 1 except that the basis weight of the base paper was 135 g / cm ² .

Thereafter, low-density polyethylene resin (density: 0.92 g / cm ³ , MFR: 4.5 g / 10 min) was melt-extruded and coated to a thickness of 18 μm at a resin temperature of 330 ° C. on both sides of the base paper. At this time, both surfaces of the support for the photosensitive material were processed into matte surfaces such as paper.

Next, a back coat layer containing silica particles having an average particle diameter of 4 μm, gelatin 1.0 g / m ² and a hardener was applied to one surface of the support for a light-sensitive material after corona discharge treatment. Then, back coating - after the corona discharge treatment the support surface opposite to the coat layer mosquitoes - carbon black, the average silica particle and gelatin 3.5 g / m ² of particle size 7 microns, undercoat layer made of hardener and AgBr / AgCl = neutral method halogenation to the average optimal sensitivity of particle size 0.4μ with 5/95 made halide composition consisting substantially of [1,0,0] face in combination sensitized by sulfur sensitization and gold sensitization Including silver emulsion, in addition to gelatin necessary for film formation, appropriate amount of stabilizer, sensitizing dye for ortho,
Phenidone, coating aids, 1.0 g / m ² with silver nitrate amount emulsion containing hardening agent, and multilayer coating at a coverage equivalent to gelatin 1.0 g / m ^2. After coating and drying, the mixture was heated at 40 ° C. for 3 days, and a coating solution comprising a copolymer of acrylamide and imidazole, hydroquinone, palladium sulfide nucleus and the like was coated on the emulsion layer at a rate of 1.0 g / m 2 of palladium sulfide sol. ² to obtain a lithographic printing plate photosensitive material.

The coated and dried sample was rolled for 50 minutes.
After storage at 81 ° C. and 81% for 4 days, it was cut, and then subjected to diffusion transfer development to count the number of spot defects.

[0062] As a result, discoloration occurs number by silver color change reaction in the sample of the present invention using wood kraft pulp is 2.25 per A-4, plaque Ten'yue disabilities was not observed at all. On the other hand, in samples other than the present invention using wood kraft pulp in which the number of discoloration generated by silver discoloration reaction is 28 per A-4, many spot failures such as transfer silver missing or thinning in spots were observed. Admitted.

Example 6 In Example 1, the conditions for the oxygen delignification treatment were as follows:
Except for (1) or (2), carry out in the same manner as in Example 1,
The same results as in Example 1 were obtained.

Condition (1): The pulp concentration was 20% by dry weight of unbleached pulp, the amount of caustic soda and oxygen was 3% by weight and 2.1% by weight, respectively, based on the absolute weight of unbleached pulp, the processing temperature and the processing time. 110 ° C. and 30 minutes, respectively.

Condition (2): The pulp concentration was 27% by weight in terms of the absolute dry weight of the unbleached pulp, and the added amounts of caustic soda and oxygen were 2.0% by weight and 1.5% by weight in terms of the absolute weight of the unbleached pulp.
%, Processing temperature and processing time are 98 ° C. and 2 hours, respectively.

Example 7 In Example 1, the same results as in Example 1 were obtained except that the same amount of caustic soda was used as the alkali in place of caustic soda, and the same amount of caustic soda was used as in Example 1. Obtained.

[0067]

According to the present invention, there is provided an excellent support for a light-sensitive material using a paper mainly composed of natural pulp as a substrate, in which the tendency of spot defects to occur in the silver halide light-sensitive layer is remarkably suppressed. I can do it.

Claims (4)

(57) [Claims] 1. A photosensitive material support comprising a base paper mainly composed of natural pulp coated with a film-forming resin, wherein a part or all of the natural pulp constituting the base paper is natural kraft pulp; The natural kraft pulp is subjected to a washing treatment in the unbleached stage after the cooking by the kraft method in the presence of an antifoaming agent or a defoamer, and an oxygen delignification treatment before and after the washing treatment, and bleaching in a subsequent bleaching stage A-4, wherein the number of discoloration occurrences of the natural kraft pulp by the silver discoloration reaction defined below is A-4.
A support for a light-sensitive material, wherein the number of support is 20 or less. Number of discoloration generated by silver discoloration reaction: A natural kraft pulp sample (sample weight: 7 as a sample condition) was applied to the silver surface of a silver plate prepared based on Tappi Standard T444.
50 g / m ² ± 150 g / m ² , absolute dry water content; 20% by weight ± 5
% By weight, pH: 6.0 to 7.5 as the pH of the pulp suspension when prepared based on Tappi Standard T205.
), Sealed in a black plastic bag, and heated at a temperature of 50 ° C ± 1 ° C and a relative humidity of 81% ± 2% for 50 hours under a load of 2.5 kg per A-4. Thereafter, the number of occurrences of silver discoloration reaction on the silver surface was measured. 2. The support according to claim 1, wherein the defoaming agent or the defoaming agent contains a mineral oil as a component. 3. The amount of the antifoaming agent or the defoaming agent in a total amount of 0.1 kg to 1.5 per ton of dry weight of unbleached pulp.
5. The support for a photosensitive material according to claim 1, wherein the weight is kg. 4. The number of discoloration occurrences due to silver discoloration reaction is A-
6. The support for a photosensitive material according to claim 1, wherein the number of the support is 4 or less.