JPH01262538A - Silver halide photographic material - Google Patents

Abstract

PURPOSE:To improve the reproducibility of a fine line in a photographic image, a fine line density and the contrast of a brightness in a white ground, and the appearance of the photographic image by incorporating a water-insoluble brightening agent dispersed with a white plastic pigment and a high b.p. solvent in a layer contg. an inorg. white pigment mounted on the supporting body of the title material. CONSTITUTION:The photographic material is constituted of the inorg. white pigment mounted on the one side or the both sides of the supporting body, and a silver halide emulsion layer mounted on the inorg. white pigment layer, and the water-insoluble brightening agent dispersed with a white plastic pigment and the high b.p. org. solvent is incorporated in the inorg. white pigment layer. The mixing ratio of the inorg. white pigment and the white plastic pigment is preferably a range of (1/3)-(3/1). The compounding ratio of the white pigment is in a range of >=60wt.% based on the total solid contd. in the layer contg. the white pigment. Thus, the sharpness of the photographic image and the reproducibility of the fine line are remarkably improved, and the generation of fogging is reduced at the time of producing the photographic material by applying a photographic emulsion, and the brightness of the white ground and the fine line contrast in a printing paper after development processings are improved, and the silver halide photographic material having the improved appearance and pressure fogging characteristics such as the folding and the scratch of the printing paper, etc., is obtd.

Description

DETAILED DESCRIPTION OF THE INVENTION (A) Industrial Application Field The present invention reduces overlap in the photographic emulsion coating process of silver halide photographic light-sensitive materials, improves fine line reproducibility, and improves white background whiteness of photographic paper after processing. This invention relates to a silver halide photographic material with improved fine line contrast and improved grain.

(B) Prior art and its problems Speeding up the development process of photographic materials is a recent trend.
As part of this, so-called water-resistant photographic paper using polyolefin-coated paper as a support has been developed and put into practical use.

Water-resistant photographic paper, whose support is polyolefin-coated paper coated on both sides with polyolefin, a hydrophobic resin, has less fatigue in the processing solution because the support does not easily absorb the processing solution, and it is easy to wash the processing solution with water. And the time required for drying is significantly reduced. Furthermore, it has advantages such as excellent dimensional stability.

However, compared to photographic images obtained from photographic materials having conventional baryta paper as a support, photographic images obtained from photographic materials having polyolefin-coated paper as a support have a disadvantage of poor sharpness.

The cause of this defect is that the amount of white pigment kneaded into the polyolefin layer covering the surface of the support that is in contact with the photosensitive silver halide emulsion layer is small, and the light shielding effect is insufficient. This is thought to be because the particles are scattered in the polyolefin layer. Titanium oxide is usually used as the white pigment contained in the polyolefin layer, but
JP-A-55-108658, JP-A-57-35855, etc. disclose improvements to the surface coating of titanium oxide so as to increase the amount of titanium oxide filled into polyolefin, and other pigments may also be used. It is disclosed in Japanese Patent Publication No. 49-27046 that it can be used in combination with. However, in either case, the possible filling amount of titanium oxide is at most 15 wt%.
It's a stop.

In addition, as a method to improve the deterioration of sharpness, JP-A-57-
64235, that is, providing a hydrophilic colloid layer containing a white pigment and a dye that can be decolorized in the development process between the polyolefin-coated paper support and the photosensitive silver halide emulsion layer was devised. ing.

It has also been devised to use the method described in JP-A-59-177542, that is, to provide I- in which a white pigment is contained in a hydrophilic colloid layer at a content of 40 vol/h or more.

It is believed that when the content of white pigment in these layers is high, the degree of light scattering in the layers is reduced, and the sharpness of the photographic image is significantly improved. However, actual white pigment particles are not spherical, and the particle size is also not constant. In addition, the state of dispersion of pigment particles in the hydrophilic colloid layer is not always uniform in reality, and the improvement in sharpness cannot be said to be perfect. Furthermore, it was found that R1 was more likely to be damaged by rubbing or scratching, and that pressure exposure due to folding of the photographic paper was worsened. It has also been devised to obtain photographic paper with improved sharpness by the method described in JP-A-62-250441, ie, by providing a layer containing a white inorganic pigment or a plastic pigment.

However, when a photosensitive layer is laminated and coated on top of this layer due to manufacturing problems, increasing the amount of pigment to increase the whiteness impairs the whiteness of the white background surface after processing the photographic paper. That is, it was found that fogging, which is thought to be caused by overdrying, is more likely to occur, resulting in a decrease in whiteness and particularly deterioration in sharpness, fine line reproducibility, and appearance. This is a serious drawback in the field of imaging.

It is important that the hue of the finished product after processing the photographic paper looks good as a printed product.Increasing the whiteness to 6% is desirable because it improves the contrast in combination with the reproduction of fine lines in the image, etc. It is something.

Fluorescent whitening has been commonly used as a method to improve the whiteness of photographic paper. One method is to add an optical brightener to the paper support, and another method is to add an optical brightener to the laminate J@ of polyethylene laminate paper. There is also a method of adding it to an emulsion layer or a protective layer of a light-sensitive material.

It is also practiced to add a fluorescent brightener to a developing agent in advance and apply it during the developing process of photographic paper.

When using the method of adding an optical brightener into the polyethylene 2-laminate layer, there are manufacturing disadvantages in that the optical brightener tends to separate thermally during high-temperature veneer processing, and the optical brightener does not increase during the development process. The method of processing by adding a whitening agent has the problem of being difficult to use because it is necessary to control the development processing conditions in order to dye a certain amount of fluorescent whitening agent. In addition, in the method of adding a fluorescent brightener to the emulsion layer, poor desilvering properties and dye removal during development are likely to cause defects. Furthermore, when an optical brightener is added to the i1M, there is a problem that the optical brightener flows out of the layer, especially in the case of a water-soluble optical brightener. In addition, water-insoluble products use Takasago-like solvents and latex used when dissolving and dispersing optical brighteners, which significantly deteriorates the physical properties of the surface film and prevents blocking due to adhesion between film surfaces under high humidity conditions. There are problems that can cause uneven gloss on the skin and the belly. On the other hand, as mentioned above, in the undercoat layer containing white inorganic pigment, drying due to stress during drying, pressure due to M rubbing and scratching, drying due to stress on the white background of photographic paper, pressure due to MW and pulling out. There are problems such as a drastic reduction in the whiteness of the white background of photographic paper.

(C) Object of the Invention The first object of the present invention is to provide a silver halide photographic material with improved sharpness and fine line reproducibility of photographic images. The second object of the present invention is to provide a silver halide photographic material with reduced fogging during the emulsion coating process of a photographic material. The third objective is the white background brightness and MA of the print-paper after development processing.
To provide a silver halide photographic material with improved fine line contrast and improved appearance. A fourth object is to provide a silver halide photographic material which has good resistance to pressure due to folding, scratching, etc. of photographic paper.

(D) Description of the invention The present inventors have proposed a photographic material in which an inorganic white pigment is provided on one or both sides of a photographic support, and a silver halide emulsion layer is provided on the inorganic white pigment layer. By containing a white plastic pigment and a water-insoluble optical brightener dispersed in a high-boiling organic solvent, the sharpness and meticulous reproducibility of photographic images are significantly improved, and the fogging during manufacturing of photographic emulsion coatings is reduced. It was discovered that by improving the white background whiteness and fine line contrast of photographic paper after processing, it is possible to obtain a silver halide photographic material with improved appearance and good resistance to stress such as bending and scratching of the photographic paper. be.

More specifically, the mixing ratio of the inorganic white pigment and the white plastic pigment is not particularly limited, but is preferably in the range of 1/3 to 3/1.

The content of these white pigments can be achieved as long as it exceeds 60% by weight of the total solids in the layer, but in order to fully exhibit the effect and maintain a practically sufficient film strength, ,
A range of 70 to 95 thick is preferred. The total coating amount of these white pigments need not be at least 3 or more, and is preferably 42β or more in order to fully exhibit the effects of the invention.

The thickness of the white pigment-containing hydrocolloid layer is naturally determined from the above content and coating amount, but is in the range of 1 to 10 microns, more preferably in the range of 3 to 8 microns.

The white pigment layer in the present invention is preferably adjacent to the silver halide photosensitive layer, but may be in contact with another hydrophilic colloid layer (referred to as an intermediate layer).

However, in this case, the thickness of this intermediate layer must be 3 μm or less, preferably 1 μm or less; if it exceeds this, the sharpness improvement effect of the present invention will be significantly reduced.

Inorganic white pigments that can be used in the present invention include titanium dioxide, barium sulfate, lithopone, alumina white calcium carbonate, silica white, antimony trioxide, titanium phosphate, zinc oxide, lead white, gypsum, etc. Titanium dioxide is particularly effective.

Such titanium dioxide may be of rutile type or anatase type, and may be produced by either the sulfate method or the chloride method. Also, it may be surface-treated or not. Examples of white plastic pigments that can be used in the present invention include spherical polyester, polystyrene dispersion, and styrene.
Powdered acrylic resins and emulsion carbon dispersions of these resins are used. Further, it is also possible to use a material that causes core-shell polymerization in which acrylic and styrene are combined into a spherical shell shape by adding a crosslinking agent to form particles with a strong hollow structure.

Any particle size of the white plastic pigment and the inorganic white pigment having an average particle size of 0.1 .mu.m to 1.0 .mu.m is effective, but those having an average particle size of 0.2 .mu.m to 0.4 .mu.m are particularly preferred.

To make a dispersion of a water-insoluble optical brightener in a high-boiling organic solvent, for example, the optical brightener is dissolved in a high-boiling organic solvent as seen in British Patent No. 1072915, and this is mixed with a hydrophilic colloid such as gelatin. This is a method of emulsifying and dispersing it together with a surfactant.

As high boiling point organic solvents, those with a staining temperature of 150° C. or higher at a pressure are suitable for M.

This type of organic solvent can be selected from carboxylic esters, carboxylic esters, carboxylic amides, ethers, and substituted hydrocarbons.

Specific examples include di-n-butyl phthalate, di-isooctyl phthalate, dimethoxyethyl phthalate, di-n-butyl adipate, diinooctyl azelenate, Tri-n-7'-thyl citrate, tricresyl phosphate, tri-n-butyl phosphate, tri-octyl phosphate, N-N-diethylcaprylic acid amide, N@N-dimethylbalmitic acid amide, n-butyl-m -Puntadecyl phenyl ether, ethyl-2
．． Examples include 4-tert-butylphenyl ether and chlorinated paraffin.

As a water-insoluble optical brightener, for example, British Patent No. 7862
Substituted stilbenes, substituted coumarins, and substituted thiophenes described in US Pat. No. 3,135,762 are useful. Particularly useful optical brighteners include those having the following formula:

Yl and Y2 represent an alkyl group, and zl and z2 represent hydrogen or an alkyl group.

Next, the following can be mentioned as water-insoluble optical brighteners used in the present invention.

The amount of optical brightener used varies depending on the type of optical brightener, the type of oil used for emulsification, concentration, etc., so it cannot be stated uniformly, but the amount of optical brightener used in the present invention is 5 to 200 g. It is most preferably used in a range of 20 to 100'' Ii.

In addition, for dissolving and dispersing the optical brightener and the organic solvent in the colloidal solution, methyl acetate, ethyl acetate, butyl propionate,
Gelatin, etc. containing 8% in a low boiling point solvent such as cyclohexanol, anionic surfactants such as alkylbenzenesulfonic acids and alkylbenzenesulfonic acids, and nonionic surfactants such as nrubitan sesquioleate and sorbitan monolaurate. It can be mixed with an aqueous solution containing a hydrophilic colloid substance and emulsified and dispersed using a colloid mill, homogenizer, ultrasonic dispersion device, or the like.

As the binder for the white pigment-containing hydrocolloid layer of the present invention, any hydrocolloid-forming material commonly used in photographic materials can be used. For example, natural polymer compounds such as gelatin and gelatin derivatives,
Synthetic polymers such as polyvinyl alcohol, polyvinylpyrrolidone, etc., but also mixtures of binders can be used.

Further, in addition to the binder, white pigment, and water-insoluble optical brightener, materials added to the emulsion layer of the photographic material can be added to the hydrocolloid layer. For example, a surfactant as a spreading aid, a hardening agent, an antifogging agent, etc. The photographic light-sensitive material of the present invention includes a hydrophilic colloid layer containing the white plastic pigment, an inorganic white pigment, and a water-insoluble optical brightener. In addition, a white pigment may also be contained in the synthetic resin film covering the paper substrate.

In this case, it is particularly preferable to incorporate a white pigment into the synthetic resin film on the side to which the silver halide photosensitive layer is applied.

As the synthetic resin film of the photographic light-sensitive material of the present invention, a film formed from polyolefin, polyester, etc. can be used, but polyolefin is preferable, and polyethylene and polypropylene are particularly preferable.

However, the support for the photographic light-sensitive material of the present invention is preferably polyolefin resin-coated paper, but is not limited to this, and other known photographic supports, such as polyester film, may also be used. can.

The silver halide emulsion used in the photographic material of the present invention includes:
Various chemical sensitizers can be used.

Namely, sulfur sensitization using @yellow-containing compounds that can react with active gelatin and silver (e.g., thiosulfates, thioureas, mercapto compounds, rhodanines); reducing substances (e.g., stannous salts); , amines, hydrazine derivatives, formamidine sulfinic acid, silane compounds): Noble metal compounds (e.g., total complex salts,
Pt, Ir.

A noble metal sensitization method using complex salts of metals of group 1 of the periodic table (such as Pd) can be used alone or in combination.

Specific examples of these are U.S. Pat.
No. 574,944, No. 2,410.689, No. 2
, 278,947, 2,728,668, 3,656,955, etc. Regarding reduction sensitization methods, see U.S. Patent No. 2,983.609, 2,419,974, No. 4,054,458, etc., and U.S. Patent Nos. 2,399,083 and 2,448 regarding noble metal sensitization methods.
No. 060, British Patent No. 618,061, etc. are described in various documents.

The photographic emulsion used in the present invention may contain various compounds for the purpose of preventing capri during storage or photographic processing of the light-sensitive material or for stabilizing photographic performance. i.e., azoles, such as benzothiazolium salts, nitroindazoles, triazoles, benzo); IJ azoles, benzimidazoles (particularly nitro- or halogen-substituted); heterocyclic mercapto compounds, such as mercaptothiazoles, mercapto; benzothiazoles, mercaptobenzimidazoles,
Mercaptothiadiazoles, mercaptotetrazoles (especially 1-phenyl-5-mercaptotetrazole)
, mercaptopyrimidines; the above-mentioned heterocyclic mercapto compounds having a water-soluble group such as a carboxyl group or a sulfone group; thioketo compounds such as oxazolinthione;
Azaindenes, such as tetraazaindenes (especially 4
Many compounds known as antifoggants or stabilizers can be added, such as -hydroxy-substituted (le3#3a#7)tetraazaindenes; benzenetheosulfonic acids; bezenesulfinic acid; and the like.

The photographic emulsion layer or other hydrophilic colloid layer of the light-sensitive material of the present invention may contain coating aids, antistatic agents, slippery improvement, emulsification dispersion, adhesion prevention, and photographic property improvement (for example, development acceleration,
Various surfactants may be included for various purposes such as increasing contrast and increasing g.

For example, saponins (steroids), alkylene oxide derivatives (e.g. polyethylene glycol, polyethylene glycol/polypropylene glycol condensates, polyethylene glycol alkyl ethers or polyethylene glycol alkyl aryl ethers, polyethylene glycol esters, polyethylene glycol alkyl ethers, polyalkylene glycols) Nonionic surfactants such as alkylamines or amides, polyethylene oxide adducts of silicone), glycidol derivatives (e.g. alkenylsuccinic acid polyglycerides, alkylphenol polyglycerides), fatty acid esters of polyhydric alcohols, and alkyl esters of sugars. agents, alkyl carboxylates, alkyl sulfonates, alkylbenzene sulfonates, alkylnaphthalene sulfonates, alkyl sulfates, alkyl phosphates, N-acyl-N-alkyl taurines, sulfosuccinates/I/ Anions containing a molten group such as a carboxy group, a sulfo group, a phospho group, a sulfate ester group, a phosphate ester group, etc. Surfactants: Ampholytic surfactants such as amino acids, aminoalkyl sulfonic acids, aminoalkyl sulfates or phosphates, alkyl betaines, amine oxides; Alkylamine salts, aliphatic or aromatic quaternary ammonium salts, pyridinium Cationic surfactants such as heterocyclic quaternary ammonium salts such as , imidazolium, and phosphonium or sulfonium salts containing aliphatic or heterocycles can be used. The photographic light-sensitive material of the present invention may contain an inorganic or organic hardener in the photographic emulsion layer or other hydrophilic colloid layer.

For example, chromium salts (chromium alum, chromium acetate, etc.), aldehydes (formaldehyde, glyoxal, glitaraldehyde, etc.), N-methylol compounds (dimethylol urea, methylol dimethylhydantoin, etc.)
, dioxane derivatives (such as 2,3-dihydroxydioxane), active vinyl compounds PA (1,3,5-)lyacryloyl-hexahydro-8-)! J azine% 1,3-vinylsulfonyl-2-propatol, etc.), active non-Nrogen compounds (2,4-dichloro-6-hydroxy-8-
) riazine, etc.), mucohalogen acids (mucochloric acid,
mucophenoxychloric acid, etc.), etc. can be used alone or in combination.

For photographic processing of the light-sensitive material of the present invention, for example, Research Disclosure (Research Disclosure) is used.
re ) No. 176, pages 18-30 (RD-17643)
Known methods and known treatment liquids, such as those described in , can be applied. Depending on the purpose, this photographic processing may be either photographic processing that forms a silver image (black and white photographic processing) or photographic processing that forms a dye image. Alternatively, a method may be used in which an auxiliary natural herbal medicine is included in the light-sensitive material, for example, in an emulsion layer, and the light-sensitive material is processed in an aqueous alkaline solution or a developer to effect development.

(E) Examples The present invention will be further explained in the following examples.

Example 1 15μ of polyethylene was applied to each side of base paper with a basis weight of 801~
A white pigment layer having the following composition was formed on the support in which 12% by weight of rutile type titanium white pigment with an average particle size of 0°23μ was impregnated in the polyethylene layer on one side. ≧A cyanine sensitizing dye (0.3 mmol, 1 mol Ag 1.6F, gelatin 1.52, 1-phenyl-5-mercaptotetrazole 1 as an anticap agent, hardener 551F, anionic surfactant, etc. were added to make gelatin 1.5, hardener 35. A silver halide photographic light-sensitive material was prepared by coating it with an overprotective layer consisting of shiodo and a surfactant.

Preparation of highly stainable organic solvent dispersion of water-insoluble optical brightener
Fluorescent brightener C compound-2) 52 was heated and dissolved by adding 120 g of ethyl acetate and 80 F of a falling point organic solvent (N-octyl phthalate) to 800 tons of a 6% gelatin aqueous solution containing 3 tsl of a 5% anionic surfactant. After mixing, the mixture was stirred at high speed for 20 minutes using a homogenizer to obtain a fine particle dispersion.

Preparation of dark white pigment dispersion> Sodium salt of polycarboxylic acid (Toagosei Co., Ltd.) was added as a dispersant to 25Of rutile-type titanium oxide (t-tanpaku R-780 manufactured by Gohara Sangyo Co., Ltd.) with an average particle size of 0.23μ. Add 0.25% of titanium white to the 5% solution of Aron T-40) to make a 50% aqueous dispersion, and after dispersing by ultrasonic irradiation,
7.5 5001 was added to the Tigelatin solution, and after dispersion, an anionic surfactant and a hardening agent were added to make a total of 1000 to prepare a white pigment dispersion (human liquid). In addition, in the coating liquid formulation, emulsion clear plastic pigment (Dainippon Ink Q
@iJJ VONCOAT PP-1000) 45
'16 liquid was prepared by adding 2202.110 f as shown in Table-1.

On the other hand, liquid 1 of the high boiling point organic solvent of the water-insoluble optical brightener
80f was added and prepared as shown in Table 1.

Further, as a comparison sample, a photographic paper sample G was prepared by coating the mb silver halide emulsion without providing a white pigment layer.

These samples are exposed to light through a wedge and then developed.
It went through fixing, washing, and drying steps.

(Developer group #:) 1-Phenyl-3-pyrazolidone 12 Anhydrous sodium sulfite 4 (1 Hydroquinone
251 Sodium hydroxide 2 (1 Potassium carbonate 10 FEDTA-2Na
1 y Embodied potassium
2゜5-Methyl-benzotriazole Add 50q of water
It is assumed to be 1t.

(Fixer composition) Ammonium thiosulfate 140F anhydrous sodium sulfite 10F Sodium metaborate 15F acetic acid
13F sulfuric acid
42 Aluminum sulfate 102 Add water to make IL.

(Processing conditions) Development processing 35° C. 20 seconds Fixing processing 30° C. 20 seconds Water washing processing 18° C. 20 seconds When the density of the obtained samples was measured and photographic characteristic values were determined, all samples showed good results.

Next, regarding the white part of the processed sample, Nippon Denden Kogyo ■
The whiteness was measured using a color difference meter manufactured by NDI001DP.

Next, a resolution test chart in which the line width was changed stepwise was printed on the unexposed samples A to G, and then predetermined development, fixing, water washing, and drying treatments were performed.

Next, the streaks on the resolution test chart of each processed sample were scanned with a micro-automator (manufactured by Narumi ■) in a manner perpendicular to the line width, and minute densities in the streaks were continuously recorded.

The width of the image noise portion that deviates from the constant density in the profile on this chart was measured.

The width of the noise part of this image is small/l't, and the image reproducibility is good, and the characters are generally sharp.

It is also evaluated to have good sharpness.

(Evaluation of fine line reproducibility) Image noise width (μm) ○ mark
Good 39 or less ■ mark Acceptable 40-44 Δ mark Not acceptable 45-49 × mark 1 50 or more (evaluation of fogging) The density of the white background portion of the photographic paper after processing was measured using a Macbeth densitometer RD-519.

Coverage (Q degree on white background) Judgment; 0 ready to eat (0,00),
0,01)% Δ mark not allowed (0,02), × mark (0,03)
In addition, the degree of pressure coverage on the photographic paper is determined by making partial concave portions in the unexposed photographic paper sheet, folding it, developing it, and visually determining the degree of scratch-like coverage.

O Ready to eat, ■ Marked OK, Δ~X marked Not allowed.

(Evaluation of appearance) Thin line density White background whiteness O mark judgment Good 0.75 or more L value 94.5 or more @
l Possible 0.60-0.74 1 94.5 or more Δ I Impossible 0.60-0.74 7 94
．． 4 or less x 1 Not possible 0.60 or less 1 94.4
4 below! The measurement results for the r sample are shown in Table 1.

Samples E and F of the present invention have sharper characters than comparative samples A, C, and D, and have less white background overlap and creases. In addition, the fine line density is high and the contrast with the white background whiteness is high, so the appearance is excellent. Comparative sample B has good sharpness of characters, but overlaps and poor appearance. Blanks without a white pigment layer -〇 have poor character sharpness and poor appearance, and are poor in marketability.

Example 2 110μ thick polypropylene synthetic paper Yubo (Tamako Yuka G)
The white pigment dispersion, the plastic pigment liquid, and the water-insoluble optical brightener dispersion used in Example 1 were prepared and applied on the surface of the same material as in Example 1, and then the same silver halide emulsion as in Example 1 was applied. Table 2 shows the results of evaluating the applied samples in the same way.
Shown below.

(The following is a blank space) Table 2 As is clear from Table 2, Sample H, in which a silver halide emulsion was coated on a layer containing the white pigment of the present invention and a water-insoluble fluorescent whitening split layer, lacks this structure. Compared to comparative samples ①, J, and K, this photographic paper has sharper characters, better appearance, and is less prone to creases.

(F) Effect of the invention On the support of a photographic light-sensitive material, a layer containing a plastic pigment and a water-insoluble optical brightener dispersed in a high-spot organic solvent in a rootless white pigment-containing layer is coated with halogen. A photographic material coated with a silver oxide photographic emulsion has good reproducibility of fine lines in photographic images, good contrast with fine IQ degree and white background whiteness, and has a good appearance. In addition, there is little overlapping and bending does not occur (excellent pressure overlapping properties).

Claims (1)

[Claims] 1. In a photographic material in which an inorganic white pigment-containing layer is provided on at least one side of the surface of a photographic support, and a silver halide emulsion layer is provided on the inorganic white pigment-containing layer, the inorganic white pigment-containing layer is A silver halide photographic material characterized by containing a white plastic pigment and a water-insoluble optical brightener dispersed in a high-boiling organic solvent.