JPH02168251A - Photographic base - Google Patents

Abstract

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

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to photographic supports. More specifically, it relates to a photographic support useful for obtaining a photographic support that has antistatic properties and type printing suitability, and has a back surface that is not contaminated by processing chemicals such as color developing solutions. .

PRIOR ART AND PROBLEMS TO BE SOLVED BY THE INVENTION Photographic materials usually consist of a support and photographic constituent layers provided on the support. Such photographic constituent layers include a photographic emulsion layer, a protective layer, a subbing layer, an intermediate layer or a color mixing prevention layer,
It is composed of an anti-resist layer or a filter layer, an ultraviolet absorbing layer, and a combination thereof. For example, a single photographic material comprises an emulsion layer and its protective layer on a support. Further, a multilayer silver halide color photographic material has a multilayer arrangement in which a blue-sensitive emulsion layer and an intermediate layer, a green-sensitive emulsion layer and an ultraviolet absorbing layer, a red-sensitive emulsion layer and a protective layer, etc. are sequentially provided on a support. Each color-sensitive emulsion layer contains yellow-magenta and cyan pure-color couplers, respectively.

By the way, polystyrene terephthalate film has traditionally been used as a support for photographic materials. Hydrophobic supports such as films such as cellulose film, polystyrene film, and polycarbonate film, and resin-coated paper made of paper as a substrate and coated on both sides with film-forming resins, often polyolefin resins, are well known. . In particular, polyolefin resin-coated paper is increasingly being used as a support for photographic paper in place of the conventionally used baryta paper. The reason for this is that the polyolefin resin-coated paper used as a photographic support is hydrophobic, so processing liquids permeate along the base paper during the development and fixing processes of photographic paper, compared to baryta paper. This is because the processing time for washing, drying, etc. can be shortened.

However, these photographic hydrophobic supports have several drawbacks. A well-known drawback is that photographic materials with these hydrophobic supports tend to become statically charged during handling and attract dirt, dust, etc. In addition, as a result of the discharge of accumulated static electricity, it may cause partial capri, called static marks, in the photographic emulsion layer, which are extremely unpleasant for photographic purposes. For this reason, it is known that an antistatic coating layer called a bank coat layer is provided on the opposite side of the hydrophobic support to the side with the emulsion layer, that is, on the side of the support that is not coated with the photographic constituent layers. It is being

For example, in order to provide antistatic performance,
Colloidal silica described in No. 98, Special Publication No. 52
- Colloidal alumina as described in No. 18020,
Compounds having various carboxyl groups described in Japanese Patent Publication No. 58-9408, ethylene maleic anhydride copolymer described in Japanese Patent Publication No. 57-12980, and described in Japanese Patent Publication No. 55-69139 A water-soluble polymer compound obtained by copolymerizing an ethylenically unsaturated copolymerizable monomer having 4 or more carbon atoms and maleic anhydride, or
It is also known to use organic polymeric antistatic agents such as its salts and water-soluble film-forming polymeric anionic polymer electrolytes described in Japanese Patent Publication No. 57-53940.

It is also known to use aluminum modified small particle size colloidal silica as described in JP-A-62-150246.

However, these silver halide photographic materials comprising a hydrophobic support comprising Barafco-1 and a silver halide photographic constituent layer have one or more serious drawbacks when used. For example, when used in high-sensitivity silver halide photographic materials, static marks may not be sufficiently prevented, the antistatic performance may deteriorate after processing and the prints may stick to each other, making handling inconvenient, or components may be present in the processing bath. In some cases, a portion of the sludge may separate, resulting in an undesirable accumulation of sludge.

Furthermore, in recent years, development processing systems for silver halide color photographic materials have become systems for continuous replenishment of processing solutions or continuous reuse systems for the purpose of cost reduction. Therefore,
Contamination in color photographic processing solutions such as developing solutions and bleach-fix solutions consisting of oxidation products and oxidative polymerization products such as developing agents, development accelerators, and organic compounds eluted from silver halide color photographic materials into processing solutions. It is clear that there is a tendency for substances to accumulate and thus to deposit these contaminants on the surface of the bank coat layer of the support of color photographic materials, in other words that these back coat layers have the disadvantage of not having anti-fouling capabilities. It became.

Therefore, when a hydrophilic substance is used in combination with the backcoat layer components, the hydrophilic substance flows out into the solution during the development process, and although it is recognized that the contamination prevention property is improved, Type printing (printability) on the back coat layer, which is performed for the purpose of automatic cutting and writing screen information, deteriorates, making it difficult to satisfy both characteristics.

Furthermore, since many of the reagents having antistatic properties are water-absorbing, if they are stored in relatively high humidity, they may absorb moisture and adhere to the emulsion surface, causing blocking.

OBJECTS OF THE INVENTION Therefore, an object of the present invention is to provide a bank coat layer that has low surface electrical resistance, does not adversely affect various photographic properties, is not contaminated by contaminants in developing and fixing solutions, and has excellent type printing suitability. The object of the present invention is to provide a photographic support having the following properties.

Means to Solve the Problem As a result of various studies to achieve the above object, the present inventor has decided to add silica (in terms of Sj02) to the surface of the hydrophobic support opposite to the surface on which the photographic emulsion layer is to be provided. Solid content weight ratio of polymer latex to aluminum silica is 0.30 to 3.0 weight in terms of Al tos is 0.80 to 2.0
This was achieved by providing a back coat layer that is.

The colloidal silica used in the practice of the present invention has an AI 201 equivalent of 0.30 to 3.0 relative to silica.
Weight% of Al (=average particle size 2-7 after Lamb modification)
Colloidal silica with a nanometer diameter is preferable. This material has a smaller particle size than general-purpose colloidal silica (generally having an average particle size of 10 nm or more), and has a large specific surface area, so it has excellent antistatic properties, and its high aggregation and reactivity make it suitable for use with water-based binders. enhances interaction and improves film strength. As a specific example of this colloidal silica, Yasan Kagaku Kogyo (company)
There is a Snowtex-8S manufactured by the company.

The polymer latex used in the practice of the present invention is an aqueous dispersion of a water-insoluble polymer with an average particle size of 20 to 400 nm, and includes acrylic latex, vinegar-vinyl latex, styrene-butadiene latex, and styrene-based acrylic latex. , acrylonitrile/butadiene latex, silicone/acrylic latex, etc.

In this invention, type printing suitability, adhesive resistance,
In view of antistatic properties, film strength, etc., it is preferable that the constituent monomers of the polymer latex consist of at least styrene and acrylic monomers. In practice, styrene/acrylic latex may be used, or a mixture of styrene latex and acrylic latex may be used. Further, the minimum film forming temperature of the polymer latex according to the present invention is preferably 10 to 60°C from the viewpoint of film strength and actual drying temperature.

Acrylic latexes include homopolymers of acrylic esters such as methyl acrylate, butyl acrylate, and 2-ethylhexyl acrylate, and methacrylic esters such as methyl methacrylate and butyl methacrylate, or copolymer emulsions thereof. Copolymer emulsions of polyacrylic latex and monomers that can be copolymerized with acrylic esters and methacrylic esters, such as butadiene, styrene, silicone-modified unsaturated copolymerizable compounds, and furthermore, Examples include carboxy- or amino-modified latex.

Examples of the styrene latex include styrene-butadiene latex, carboxy-modified styrene-butadiene latex, and the like.

Specific examples of these polymer latexes include the AE series manufactured by Nippon Gosei Rubber Co., Ltd., the Dicrystal Sumer series manufactured by Nippon Tsumugi Co., Ltd., the Siren series manufactured by Hoechst Gosei Co., Ltd., the Movinyl series manufactured by Hoechst Gosei Co., Ltd., and the HD manufactured by Toagosei Kagaku Kogyo Co., Ltd. series,
There are the Polytron series manufactured by Asahi Kasei Corporation and the Bonron series manufactured by Mitsui Toatsu ■.

In the present invention, the mixing ratio of polymer latex to colloidal silica is preferably 0.80 to 2.0 in terms of solid weight ratio, more preferably 1.
It is in the range of 0 to 1.5.

0.8 polymer latex to colloidal silica
If it is less than 0, the film strength will decrease in a wet state such as during development, and the suitability for type printing will not be satisfied.On the other hand, if it exceeds 2 times, the characteristics of the polymer latex itself will be strongly expressed, and the film strength will be inferior when dry.

The support used in the practice of the present invention is a paper substrate coated on both sides with a resin capable of forming a film.

The resin for coating the base paper used in the present invention is preferably a polyolefin resin or an electron beam curable resin. Examples of the polyolefin resin include homopolymers such as low-density polyethylene, high-density polyethylene, polypropylene, polybutene, and polypentene, or ethylene and propylene. Copolymers consisting of two or more olefins such as polymers, linear low-density polyethylenes that are copolymers of ethylene and a-olefins, and mixtures thereof, with various densities and melt indexes individually. Or they can be used in combination. Particularly, in the present invention, it is preferable to use low density polyethylene, medium density polyethylene, high density polyethylene, ethylene-propylene copolymers, etc. alone or in a mixture of two or more resins.

As an electron beam curable resin, the molecular side chain or the molecular terminal has
Examples include resins having a C-to-C unsaturated bond such as an acryloyl group or a methacryloyl group. Typical examples include ester acrylate, ester methacrylate, epoxy acrylate, epoxy methacrylate,
Examples include urethane acrylate, urethane methacrylate, monofunctional acrylate, monofunctional methacrylate, polyfunctional acrylate, and polyfunctional methacrylate.

In addition, in the resin for coating the base paper in the present invention, white pigments such as titanium oxide, zinc oxide, Merck, calcium carbonate, etc., fatty acid amides such as stearic acid amide and alaxic acid amide, zinc stearate, calcium stearate, etc. , fatty acid metal salts such as aluminum stearate, magnesium stearate, zinc palmitate, zinc myristate, calcium palmitate, hindered phenol, hindered amine, 11 antioxidants such as phosphorus type, sulfur type, etc., cobalt blue, Gunyoi. , blue pigments and dyes such as cerulean blue 7 talocyanine blue, magenta pigments and dyes such as cobalt violet, fast violet, and manganese violet, optical brighteners, and various additives such as ultraviolet absorbers are added in appropriate combinations. is preferable.

The photographic support according to the present invention is manufactured by a so-called extrusion coating method in which heated and molten resin is cast onto a running base paper, and both sides of the support are coated with the resin. Further, in the case of an electron beam curable resin, the resin is applied by a commonly used coater such as a gravure coater or a blade coater, and then the resin is cured by irradiation with an electron beam for coating. Further, before coating the base paper with the resin, it is preferable to subject the base paper to an activation treatment such as a corona discharge treatment or a flame treatment.

The emulsion side surface of the photographic support has a glossy surface, a matte surface, a silky surface, etc. depending on the use, and the back surface is usually a matte surface, and the front surface or the back surface is also treated with corona discharge if necessary. Activation processing such as the following can be performed. In addition, there is no particular limit to the resin thickness of resin-coated paper, but it is generally 5 μm.
Advantageously, a coating thickness of the order of m to 50 μm is applied.

The base paper of the resin-coated paper-type photographic support used in the present invention may be any of ordinary natural pulp paper, synthetic fiber paper, or so-called synthetic paper made by bonding a synthetic resin film, but softwood pulp Natural pulp paper whose main component is wood pulp, hardwood pulp, softwood hardwood mixed pulp, is advantageously used.

There are no particular restrictions on the thickness of the base paper, but paper with good surface smoothness is preferred, and its basis weight is 50 f/rr? ~2
50 or less is preferred. Further, the base paper mainly composed of natural pulp can contain various polymer compounds and additives. For example, starch derivatives, polyacrylamides, polyvinyl alcohol derivatives, dry paper strength agents such as gelatin, fatty acid salts, rosin derivatives, sizing agents such as dialkyl ketene dimer emulsions, wetting agents such as melamine resins, urea resins, epoxidized polyamide resins, etc. paper strength enhancer,
Stabilizers, pigments, dyes, optical brighteners, latex, inorganic electrolytes, pH adjusters, and the like can be appropriately combined and used.

Various polymer compounds and additives can be contained in the barafco I'll according to the present invention.

Water-soluble polymers include starch derivatives such as oxidized starch and phosphated starch, polyvinyl alcohol, polyacrylamide, poly-N-vinylpyrrolidone, agar, and sodium alginate; surfactants include alkylbenzene sulfonates and sulfosuccinates. Anionic surfactants such as salts, nonionic surfactants such as saponin and alkylene oxide compounds, amphoteric surfactants such as amino acids, aminosulfonic acids, and amino alcohol esters,
Fluorine-based surfactants as exemplified in JP-A No. 50-99529, compounds described or exemplified in JP-A-45-24068, JP-A-54-94318, etc. can be included as fluorescent brighteners. can.

In carrying out the present invention, the equipment for applying the back coat coating liquid onto the surface of the hydrophobic support opposite to the surface on which the silver halide photographic constituent layer is provided includes an air knife coater, a roll coater, a bar coater, a flade coater, and a slide hopper coater. , a gravure coater, a flexogravure coater, and a combination thereof. Prior to coating, the surface of the hydrophobic support is subjected to corona treatment,
It is desirable to activate it by flame treatment or the like.

Various drying devices for drying the applied coating liquid include hot air dryers such as straight tunnel dryers, arch dryers, air loop dryers, sine curve air float dryers, infrared heating dryers, dryers using microwaves, etc. be able to.

The silver halide photographic emulsion layer according to the present invention includes various types. Examples include a photographic emulsion layer for enlargement positives, a photographic emulsion layer for contact positives, a photographic emulsion layer for negatives, a color photographic emulsion layer, a photographic emulsion layer for printing, a photographic emulsion layer for direct positives, a photographic emulsion layer for diffusion transfer method, etc. . Regarding the color photographic emulsion layer, for example, JP-A-62-172346 and JP-A-62-1
Contains the coupler disclosed in Publication No. 72350, 30°C or higher9
A silver halide color photographic emulsion that can be developed within 0 seconds may also be used.

In addition, such photographic emulsion layers contain binders such as gelatin and gelatin derivatives, chemical sensitizers such as hypo, noble metal sensitizers such as gold salts and platinum salts, and hexahalogenoiridium (I[
[) complexes, high contrast agents such as hexahalogenorhodium (III) complexes, nucleic acid decomposition products, JP-A-50-147925,
Crystal habit modifiers for silver halide grains such as mercapto heterocyclic compounds described or exemplified in No. 107129/1983;
Color sensitizers and stabilizers cited or exemplified in JP-A-52-65432 and JP-A-52-88340;
Anti-capri agents, couplers for color photographs, hardeners, dihydroxybenzene compounds, coating aids, fogging agents, additives for direct positive photographic emulsions such as dyes for direct positive photographs, dye developers, other additives, etc. It can be made to contain.

The silver halide photographic material according to the present invention can be exposed to light as described in "Sha-xi Optical Materials and Handling Methods" (Kyoritsu Shuppan, written by Gobe Miyamoto, Photographic Technology Course 2), in accordance with the photographic material. , development, stopping, fixing, bleaching, stabilization, etc. Multilayer silver halide color photographic materials that undergo bath bleach-fixing treatment after color development are particularly suitable for CD-1i[, CD-Pi'(
The above 2ffl compound can be processed with any number of crude drug color developers such as Kodak Co. (trade name), droxychrome (May & Peker Co. trade name), and the like. Benzyl alcohol, thallium salt, phenidone, etc. may be added to the developing solution containing the crude drug. Useful one-bath bleach-fix solutions also include metal salts of aminopolycarboxylic acids (e.g., secondary salts such as ethylenediaminetetraacetic acid, propylenediaminetetraacetic acid, etc.).
iron complex salts, etc.), and sodium thiosulfate, ammonium thiosulfate, etc. are useful as fixing agents. Such a one-bath bleach-fix solution may contain additives.

For example, desilvering accelerators (e.g., U.S. Pat. No. 3,512,9
mercaptocarboxylic acids described in Belgian Patent No. 79, mercapto-heterocyclic compounds described in Belgian Patent No. 682,426), antifouling agents, pH adjusting agents or pH buffering agents, hardening agents (e.g. magnesium sulfate, aluminum sulfate). , potassium alum, etc.), surfactants, and various other compounds can be contained in combination. Additionally, although such one-bath bleach-fix solutions may be used at a variety of pHs, the useful pH range is
6.0 to 8.0.

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

[Example 1] A sheet of paper with a size of 16 m (1/m) was run at 80 m/min, and after corona discharge treatment on the back side in the first zone, low density polyethylene (density 0.918, MI5) was processed using a melt extruder. 50
High density polyethylene (density 0.965, MI 7)
A resin composition consisting of 50 parts was applied by melt extrusion to a resin thickness of 30 μm to form a resin layer with a matte surface. After corona discharge treatment on the cover surface in the second zone, using a melt extruder, a
30 parts of a masterbatch kneaded with OZ percent titanium oxide, low density polyethylene (density 0.918, M
I 5.0) 45 parts, high density polyethylene (density 0.
965, MI7) to a resin thickness of 3.
A resin layer with a glossy surface is formed by melt extrusion coating at a thickness of 0 μm.

In the third zone, after corona discharge treatment is applied to the back resin surface, a rotating 140 mesh gravure roll is immersed in the coating liquid listed in Table 1, and the excess coating liquid is scraped off with a blade to make the coating liquid uniform. This was transferred onto a resin surface and dried to produce a photographic support with antistatic properties. The coating amount of the aqueous coating liquid was 3f~ (moisture).

After corona discharge treatment on the surface of the polyethylene-coated paper coated with these back coats (i.e., the side of the support opposite to the Barafco Jl coated side), a yellow coupler was applied adjacent to the support in order. A back-sensitive silver chloride-coated gelatin emulsion layer containing a magenta coupler and an intermediate layer, a green-sensitive silver chlorobromide gelatin emulsion layer containing a magenta coupler and an ultraviolet absorption layer containing an ultraviolet absorber, and a red-sensitive silver chlorobromide gelatin emulsion layer containing a cyan coupler. A multilayer silver halide color photographic paper was prepared by coating the film and its preservative iam using an extrusion exchange method and drying it.

Each sample obtained as described above was heated at 50°C and 60% R.
After being stored in a constant temperature and humidity bath for 1 day, the samples were evaluated by the method described below. At that time, the contact angle and antistatic performance of Parakko) Ml were numerically evaluated, and the evaluation criteria for type printing suitability, film performance, and antifouling performance of the bank coat layer were O (good) and Δ (fair). Good), marked with an X (unsatisfactory).

[Important Value of Antistatic Performance of Bank Coat Layer] The surface resistivity of the sample was measured at 20° C. and 40% RH before and after color development using a roll processor using the following processing method.

Color development (30℃, 3 minutes 30 seconds) → Bleach fixing (30℃,
1 minute 30 seconds): +Washing (30℃, 3 minutes) → Drying (45℃)
, 1 minute) [Evaluation of suitability for type printing of back coat layer] Using an in-back printer installed in an automatic printer, a type ribbon (
(For Kodak back printer manufactured by Easman Kodak)
Information consisting of numbers, letters, lines, etc. was printed in the form of a type on the surface of the back coat layer using a . One minute after printing, the printed sample was processed with a roll processor, and the state of disappearance of the print was observed and judged.

[Evaluation of film performance of back coat layer]

The degree of scratches on the bank coated surface of the photographic paper was determined when the back coated surface of the photographic paper was brought into contact with a nylon scrubber and moved at a constant speed under a constant load.

[Evaluation of contamination prevention performance of bank coat layer] A sample was immersed for 3 minutes and 30 seconds in a color developing solution that had been heated at 50°C for 2 days to generate blackish brown tar-like deterioration products, and then washed by exposing it to a stream of water for 3 minutes. The contamination status of the bank coat surface was evaluated.

The results obtained are shown in Table 2.

(Left below) As shown in Table 2, when using colloidal silica that has not been modified with aluminum even though the average particle size is the same (
A14.15) even if an aluminum source coexists in the coating liquid (
415), the film strength is poor. Furthermore, these have poor coating liquid stability. Furthermore, when colloidal silica having a large average particle size is used (A16.17), the antistatic performance before and after development processing is poor. Furthermore, even if the colloidal silica according to the present invention is used, if the amount of polymer latex is too small (A
12: Bolimar latex/, eloid silica<0.
8) The suitability for type printing is poor, and the film becomes brittle and its strength decreases. On the other hand, if the amount of polymer latex is too large (A13: Polymer latex/colloidal silica) 2.0), the strength of the polymer latex itself will develop, resulting in a relatively soft film, and the stain prevention performance will also decrease. Inferior.

On the other hand, the one having the bank coat layer of the present invention (A1-1
Regarding 1), it can be seen that the support has excellent antistatic performance, type printing suitability, film performance, and stain prevention performance.

Effects of the Invention In short, by providing a coating layer made of a combination of colloidal silica and polymer latex according to the present invention, a photographic support with excellent backcoat properties including antistatic properties is provided. I can do it.

Claims (1)

[Claims] 1) On the surface of the hydrophobic support opposite to the surface on which the photographic emulsion layer is provided, 0.3.0 to 3.0% by weight of aluminum modification based on Al_2O_3 based on silica (SiO_2) is applied. A back coat layer is provided, which is made of colloidal silica having an average particle diameter of 2 to 7 nm and polymer latex, and has a solid content weight ratio of the polymer latex to the colloidal silica of 0.80 to 2.0. A photographic support characterized by: 2) The photographic support according to claim 1, wherein the constituent monomers of the polymer latex are at least styrene and acrylic monomers, and the minimum film forming temperature thereof is 10 to 60°C. 3) The dry weight of the back coat layer is 0.35 to 1.5 g.
3. The photographic support according to claim 1 or 2, which is /m^2.