JPH0610745B2 - Photographic support - Google Patents

Description

FIELD OF THE INVENTION This invention relates to improved photographic supports.
More specifically, it relates to a photographic support having improved antistatic properties without adversely affecting photographic properties.

Problems to be Solved by the Prior Art and Invention Since a photographic light-sensitive material generally comprises a support having an electrically insulating property and a photographic light-sensitive layer, contact friction or peeling between the same or different substances during the manufacturing process and during use. By receiving the static electricity tends to adsorb dust and dust, causing not only various spots such as water repellency, desensitization and fog, but also the accumulated static electricity being discharged, An antistatic back coat layer that dissipates static electricity on an electrically insulating surface to prevent serious photographic characteristic defects called static marks in the light-sensitive emulsion layer, and usually prevents this. It is known to provide a coating layer called.

Thus, various materials have been used to prevent the charging of photographic supports. These substances are ionic conductive substances or hygroscopic substances, and a method of giving conductivity to the photosensitive material and rapidly dissipating the charge before discharge due to charge accumulation is generally used. . In order to directly impart antistatic properties to the support of a photographic light-sensitive material, there is known a method of directly blending such a substance with a polymer substance as a support or coating the support on the surface of the support. For the latter, a method of coating with a polymer substance such as gelatin or polyvinyl alcohol is used in order to improve the retention of the antistatic agent.

However, in the former case, the antistatic property, photographic property,
There is no product that satisfies all of the manufacturing stability, and the latter does not show a satisfactory effect under low humidity conditions.To improve this, a large amount of ionic conductive substance or hygroscopic substance is added to the layer. If it is contained, it causes film peeling at the time of development, leading to disappearance of cutting marks or deterioration of developing solution, and also in high humidity, adhesion failure with emulsion surface or increase in fog density of emulsion,
In some cases, photographic characteristics such as development inhibition may be deteriorated.

Therefore, in the present invention, the surface electric resistance is low, the photographic characteristics are not adversely affected, the antistatic property is not impaired by the temperature and humidity during long-term storage, and the film has a strong coating property, -To provide a photographic support that does not deteriorate the fixing solution.

Means for Solving the Problems As a result of intensive studies to solve the above problems, the present inventors have found that at least chitin or chitosan is formed on the surface of the photographic hydrophobic support opposite to the photosensitive emulsion layer. It was achieved by applying a coating layer containing

By the way, chitin is poly-β (1-4) -N-acetyl-D-glucosamine and naturally exists as an organic skeleton substance of arthropods, molluscs and the like. Chitosan is a deacetylated product of chitin, and can be obtained, for example, by subjecting chitin to dealkalization. These are collected in large quantities as crusts such as crabs, shrimps, and krill.

Chitin and chitosan used in the present invention are not limited to commercially available products,
Chitin separated and purified from a chitin source according to a known method, and an intermediate substance for chitosan in which the degree of deacetylation of chitin is appropriately adjusted may be used. Chitin is soluble in solvents such as formic acid-dichloroacetic acid system, dimethylacetamide-LiCl system, dimethylacetamide-N-methyl-2-pyrrolidone-LiCl system, N-methyl-2-pyrrolidone-LiCl system, hexafluoroisopropanol, and hexafluoroacetone. Then
Then, it can be added to water as colloidal chitin, and chitosan can be used in the present invention as a mixed aqueous solution with hydrochloric acid, formic acid, acetic acid and the like, but both of them may be prepared by other methods. A 0.5% solution of chitosan aqueous solution is 500c because of its preparation and coating characteristics.
It is preferably ps or less, more preferably 100 cps or less.

The colloidal silica used in the present invention has an average particle size of 5 to 5.
This is a colloidal solution in which 40 mμ of silicic acid anhydride is dispersed in water, and “Snowtex AK” manufactured by Nissan Chemical Co., Ltd., which is a cation-modified colloidal silica, is particularly effective. Colloidal alumina has an average diameter of 10 mμ and a length of 10
Feather-like alumina of 0mμ, made by the company "Alumina sol"
Are sold under the brand name of. They show particularly good miscibility with chitosan and are very effective in antistatic properties.

The monovalent metal salt used in the present invention is a water-soluble inorganic or organic alkali metal such as titanium chloride, sodium chloride, potassium chloride, sodium nitrate, potassium sulfate, sodium formate, lithium citrate, sodium malate or sodium gluconate. It refers to a salt, and specific examples of the inorganic pigment include crystalline silica, calcined clay, alumina silica, aluminum hydroxide, alumina and the like. The inorganic pigment is one that imparts especially writability in the coating layer, and its average particle size is 0.1 to 7.0 μ, and more preferably 1.0 to 3.0 μ.
Is good. If the average particle size is less than 0.1μ, the pencil writing property will be significantly deteriorated, while if it is more than 7.0μ, it will give a rough feeling to the user, and at the same time, it may cause the lack of the pigment during the development processing or contact with the emulsion surface. There are also cases where the surface is damaged. In addition, when these inorganic pigments are used, the oil absorption is 10 in terms of the writing property (bluishness) of the oil-based ink.
It is preferably 0 C.C./100 g or less.

The above reagents may be used alone or in combination of two or more.
Further, in order to improve various properties such as coating liquid stability, coating property, and color tone, various polymer compounds, surfactants, organic agents that aid dissolution of various polymer compounds in the coating liquid containing chitosan and / or chitin of the present invention. It is also possible to add a solvent, a dye optical brightening agent and the like.

Various types of hydrophobic supports can be used in the practice of the present invention. For example, synthetic papers such as polypropylene and polystyrene, films such as cellulose acetate, polyethylene terephthalate, polyvinyl acetate, polystyrene, and polycarbonate, and resins having film-forming ability such as polyolefin and polyvinyl chloride on both surfaces of paper as a substrate, most of which are A resin-coated paper coated with a polyolefin resin can be used. Especially for photographic paper that requires good type printing and anti-contamination properties,
Among them, as a support for color photographic paper, a polyolefin resin-coated paper is advantageously used because the effect of the present invention is more remarkably exhibited.

Further, in the thermoplastic resin film or the resin layer of the resin-coated paper, titanium oxide, zinc oxide, talc,
White pigments such as calcium carbonate, fatty acid amides such as stearic acid amide, dispersants such as fatty acid metal salts such as zinc stearate and magnesium stearate, ultramarine blue, pigments and dyes such as cobalt violet, antioxidants, optical brighteners It is preferable that various additives such as an ultraviolet absorber are appropriately combined and contained.

The polyolefin resin-coated paper advantageously used in the practice of the present invention is manufactured by extrusion-coating a molten polyolefin resin in a film form on a running base paper through a slit die.
At that time, prior to the melt extrusion coating, the base paper surface was corona treated,
It is desirable to activate by flame treatment or the like. The thickness of the coating resin layer is not particularly limited, but generally 5 to
About 50μ is advantageous. The side of the polyolefin resin coated paper on which the silver halide photographic constituent layer is provided has a glossy surface, a matte surface, a silk surface, etc. depending on the purpose, and the back surface is usually a matte surface.

The polyolefin resin for coating the polyolefin resin-coated paper which is advantageously used in the practice of the present invention includes low density polyethylene, high density polyethylene, homopolymers of olefins such as polypropylene, or two or more kinds of olefins such as ethylene-propylene copolymer. Examples of the copolymers include a mixture thereof and a mixture thereof, and those having various densities and melt viscosity indexes (melt indexes; hereinafter simply referred to as MI) can be used alone or as a mixture. The base paper of the polyolefin resin-coated paper may be any of ordinary natural pulp paper, synthetic fiber paper or so-called synthetic paper obtained by quasi-synthesizing synthetic resin film, but softwood pulp, hardwood pulp, softwood mixed pulp wood. Natural pulp paper based on pulp is advantageously used. Not specifically defined, the thickness of the base paper is preferably smooth good paper surface, the basis weight 50g / m ² ~250g / m ² is preferred. Further, the base paper containing natural pulp as a main component may contain various polymer compounds and additives, for example, starch derivative, polyacrylamide, polyvinyl alcohol derivative, dry paper strengthening agent such as gelatin, Sizing agents such as fatty acid salts, rosin derivatives, dialkyl ketene dimer emulsions,
Wet paper strength enhancer such as melamine resin, urea resin, epoxidized polyamide resin, stabilizer, pigment, dye, optical brightener,
A latex, an inorganic electrolyte, a pH adjusting agent and the like can be appropriately combined and contained.

In the practice of the present invention, as a device for applying a coating liquid for a back coat on the opposite side of the hydrophobic support on which a photographic emulsion layer is provided, an air knife coater, a roll coater, a bar coater, a blade coater, a slide hopper coater, Examples include gravure coaters, flexo gravure coaters and combinations thereof. Before coating, it is desirable to activate the hydrophobic body surface by corona treatment, flame treatment, etc. as a drying device for the coating liquid applied, a straight tunnel dryer, arch dryer, air loop dryer, signature Hot air dryer such as curve air float dryer, infrared ray, heating dryer,
Various dryers such as dryers using microwaves can be used.

The photosensitive photographic emulsion layer according to the present invention includes various types. For example, a photographic emulsion layer for enlargement positive, a photographic emulsion layer for adhesion positive, a photographic emulsion layer for negative, a color photographic emulsion layer,
Photographic emulsion layers for printing are directly subjected to positive processing, but especially, multilayer silver halide color photographic materials which undergo one-bath bleach-fixing processing after color development are CD-III and CD-IV (the above two compounds are Kodak Corporation. No.), droxychrome (trade name of May and Baker Co., Ltd.) and any other main color developing solution. A developer containing the main agent may contain benzyl alcohol, thallium salt, phenidone, or the like. A useful one-bath bleach-fixing solution is a solution of a metal salt of aminopolycarboxylic acid (for example, a ferric complex salt of ethylenediaminetetraacetic acid, propylenediaminetetraacetic acid, etc.), and a fixing agent such as sodium thiosulfate or thiosulfate. Ammonium sulfate and the like are useful. The one-bath bleach-fixing solution may contain various additives. For example, a desilvering accelerator (for example, mercaptocarboxylic acid described in US Pat. No. 3,512,979, a mercapto-heterocyclic compound described in Belgian patent 682,426, etc.), an antifouling agent,
Various compounds such as a pH adjusting agent or a PH buffering agent, a hardener (for example, magnesium sulfate, aluminum sulfate, potassium alum, etc.) and a surfactant can be contained in combination. Further, although such a one-bath bleach-fixing solution can be used in various PHs, a useful PH region is PH 6.0 to 8.0.

(Examples of the Invention) Next, examples will be described to more specifically describe the present invention.

Example A paper having a basis weight of 160 g / m ² was run at 80 m / min, and after the corona discharge treatment was applied to the back surface in the first zone, 50 parts of low density polyethylene (density 0.918, MI = 5) was used by using a melt extruder. A resin composition comprising 50 parts of density polyethylene (density 0.965, MI = 7) is melt-extrusion coated with a resin thickness of 30 μm to form a matte surface resin layer. After the corona discharge treatment on the cover surface in the second zone, 30 parts by weight of low-density polyethylene (density 0.918, MI = 8.5) kneaded with 30 wt% titanium oxide using a melt extruder, low-density polyethylene (density A resin composition consisting of 45 parts of 0.918, MI = 5) and 25 parts of high-density polyethylene (density of 0.965, MI = 7) is melt-extrusion coated with a resin thickness of 30 μm to form a resin layer having a glossy surface. In the third zone, after the back resin surface was subjected to corona discharge treatment, a rotating 140 mesh gravure roll was dipped in the coating solution shown in Table 1 to scrape off the excess coating solution with a blade to make the coating solution constant, The surface was dried to produce a photographic support having antistatic performance. The coating amount of the aqueous coating liquid was 3 g / m ² (moisture).

The colloidal chitin and chitosan were prepared as follows. Colloidal chitin is N, N-dimethylacetamide 1
5 kg of lithium chloride and 0.5 kg of chitin were added to 00 kg, and the mixture was stirred for 2 days and then poured into 100 kg of water while stirring with a homomixer to obtain 1 of the obtained colloidal chitin.
Passed with 00 mesh with wire mesh. In addition, the chitosan solution was prepared by adding 2 kg of chitosan to 97 kg of water while stirring 1 kg of acetic acid, dissolving the mixture, and further raising the temperature to 60 ° C.

The surface of the polyethylene-coated paper coated with these back coats (that is, the side of the support opposite to the side coated with the back coat layer) is subjected to corona discharge treatment, and then sequentially includes a yellow coupler adjacent to the support. A blue-sensitive silver chlorobromide gelatin emulsion layer and an intermediate layer, a green-sensitive silver chlorobromide gelatin emulsion layer containing a magenta coupler, an ultraviolet absorbing layer containing an ultraviolet absorber and a red-sensitive silver chlorobromide gelatin emulsion layer containing a cyan coupler The protective layer was applied by an extrusion method and dried to prepare a multilayer silver halide color photographic printing paper.

Each sample obtained as described above was heated at 50 ° C. and 60% RH.
After being stored in the constant temperature and humidity chamber for 1 day, it was evaluated by the method described below.

[Evaluation of antistatic performance of back coat layer]

For the sample before color development, the surface specific resistance (value after 1 minute from the start of measurement) when the humidity was controlled at 20 ° C. and 30 RH for 3 hours was measured (indicated as “before development”). Further, the surface specific resistance of the sample after the color development image by the roll processor of the following processing system was measured under the condition of 20 ° C. and 30 RH (displayed after development).

Color development (30 ° C, 3 minutes 30 seconds) → bleach-fixing (30 ° C,
1 minute and 30 seconds) → Washing (30 ° C., 3 minutes) → Drying (45 ° C.,
1 minute) [Evaluation of film strength of back coat layer] Examine the degree of scratches on the back coat surface of photographic paper under constant load on a nylon scrubbing soaked in a developer when the back coat surface is moved at a constant speed. It was A is the evaluation standard
It was indicated by (almost no scratches), B (slight scratches were generated), C (slight scratches were slightly increased), D (scratches were frequently generated), and E (scratches were very frequently generated).

[Evaluation of Pencil Writing Properties of Backcoat Layer]

The sample coated with the coating liquid containing the pigment was used for writing with a pencil of HB, and the writing state was observed and evaluated.

[Evaluation of the back stain prevention performance of the back coat layer]

According to the developing method and conditions used in the evaluation of antistatic performance, when a developing solution developed by using a color developing solution which has been heated to 60 ° C. for 2 days and forcibly abolished is used, the degradation product of the developing solution to the back coat layer is The degree of transfer was evaluated.

Good> A> B> C> D> E> Poor Table 2 shows the obtained results.

As can be seen from Table 2, the coating layer containing at least one of chitin and chitosan of the present invention has a tough film strength, is free from developer contamination, and is a photographic support excellent in antistatic property. can get.

Claims (3)

[Claims] 1. A photographic support having improved antistatic properties, comprising a coating layer containing at least one of chitin and chitosan provided on one surface of a hydrophobic support. 2. The photographic support according to claim 1, wherein the coating layer further contains at least one of colloidal silica and colloidal alumina. 3. The photographic support according to claim 1, wherein the coating layer further contains at least one kind of a monovalent metal salt and an inorganic pigment having a number average particle size of 0.1 to 7.0 μm. body.