JPH0443575B2 - - Google Patents

Description

[Detailed description of the invention]

A. Field of Industrial Application The present invention relates to a resin-coated paper-type photographic support that has improved adhesion to photographic emulsions and coatability of photographic emulsions. More specifically, the present invention relates to a resin-coated paper-type photographic support coated with a gelatin-containing coating solution. B. Prior Art and its Problems Generally, silver halide photographic materials are composed of a support and a silver halide photographic constituent layer provided on the support. Such silver halide photographic constituent layers include a silver halide photographic emulsion layer, a protective layer, a subbing layer, an intermediate layer or color mixing prevention layer, an antihalation layer or filter layer, an ultraviolet absorbing layer, etc., and combinations thereof. It is what was done. For example, a single silver halide photographic material has a silver halide emulsion layer and its protective layer on a support. In addition, 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 color forming couplers. Incidentally, supports for silver halide photographic materials have conventionally been made of films such as polyethylene terephthalate film, cellulose triacetate film, polystyrene film, polycarbonate film, paper as a substrate, and resins capable of forming films on both sides, often polyolefin resins. Hydrophobic supports such as resin-coated papers coated with In particular, polyolefin resin-coated paper is increasingly being used as a support for photographic printing 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 the development of photographic printing paper is faster than that of baryta paper.
This is because the processing liquid is less likely to penetrate into the base paper layer during the fixing process, which has the advantage of shortening processing times such as washing and drying. However, such a hydrophobic support cannot be coated with an aqueous silver halide photographic emulsion as it is. As countermeasures against this problem, flame treatment, corona treatment, subbing treatment, etc. of the surface of the hydrophobic support are generally known. Among these, flame processing has problems such as inconvenience in handling and control, and corona processing has problems such as a decrease in water wettability due to the elapse of time after processing until coating the photographic emulsion. Furthermore, undercoat treatment is inconvenient to handle in the case of a solvent coating method, and additional treatment is usually required to ensure water wettability. In addition, in the aqueous coating method, there is a risk that the constituent substances of the undercoat layer will diffuse into the photographic emulsion layer during coating of the photographic emulsion, thereby adversely affecting photographic performance. Therefore, undercoating based on gelatin, which is one of the constituent elements of photographic emulsions, is extremely advantageous and has been widely used up to now.
However, when a gelatin-based undercoat is coated in a large amount and is rapidly dried at a high temperature, the gelatin-coated surface is disturbed, resulting in uneven thickness, which leads to uneven thickness of the emulsion layer during subsequent emulsion coating. Therefore, even when applying the undercoat layer, it is necessary to solidify the gelatin in a cooling zone and dry it by precisely controlling the drying speed, which may limit the production speed or force the installation of extensive drying equipment. That was the result. On the other hand, when the coating amount of the undercoat layer was reduced to such an extent that even if the thickness unevenness of the undercoat layer occurred, the thickness unevenness of the emulsion layer did not occur, the adhesion between the emulsion layer and the support became insufficient. C. Purpose of the Invention Therefore, the purpose of the present invention is to ensure sufficient adhesion of the emulsion layer with a simple undercoat mainly composed of gelatin, and to prevent uneven thickness of the emulsion layer when the emulsion is coated in the next step. The objective is to provide a photographic support with no D. Structure of the Invention The object of the present invention is to provide a resin-coated paper-type photographic support in which both sides of the paper are coated with a film-forming resin, at least gelatin and its preservative on the resin side on which a photographic light-sensitive layer is to be provided. A coating layer containing an ester of paraoxybenzoic acid is provided in advance, and the coating amount of the coating layer is 0.01 to 0.1 g/m ² and the coating amount of the preservative is 0.2 to 20% by weight based on the coating amount of gelatin. This is achieved with certain photographic supports. Gelatins that can be used in the practice of the present invention include lime-treated gelatin, acid-treated gelatin, enzyme-treated gelatin, and gelatin derivatives such as gelatin reacted with dibasic acid anhydrides.
Any material commonly used in the art can be used. Preservatives that can be used in the practice of the present invention include those for various uses such as those for wood, fibers, glues, and foods, and those with chemical structures such as inorganic compounds, organic compounds, and organometallic compounds. Although the structure can be selected from the viewpoint of not interfering with the performance of the photographic photosensitive layer, and if the photosensitive layer is a silver halide color photosensitive layer, it is further important to ensure that it does not affect the color forming couplers of each color. In view of this, esters of paraoxybenzoic acid are particularly preferred. The amount of preservative used varies depending on the type of preservative used, but is approximately 0.2 of the amount of gelatin used.
It is best to use ~20% by weight. In carrying out the present invention, there is no particular restriction on the coating amount of the undercoat layer, but it is preferably 0.001 to 1.0.
g/m ² , particularly preferably 0.01 to 0.1 g/m ² . The coating liquid for undercoat used in the practice of the present invention includes various surfactants such as anionic, cationic, amphoteric, or fluorine-based surfactants, PH regulators or PH buffers,
A hardening agent for gelatin, a toning agent, a brightening agent, a filler, etc. can be included as appropriate. Examples of the hydrophobic support used in the practice of the present invention include resin-coated paper in which a paper substrate is coated on both sides with a film-forming resin such as polyolefin, polystyrene, or polyvinyl chloride, often with a polyolefin resin. can. In particular, polyolefin resin-coated paper is advantageously used because of its good processability. In addition, the resin layer of these resin-coated papers contains white pigments such as titanium oxide, zinc oxide, talc, and calcium carbonate, fatty acid amides such as stearic acid amide and arachidic acid amide, zinc stearate, magnesium stearate, and palmitin. It is preferable to contain various additives such as dispersants such as fatty acid metal salts such as calcium acid salts, pigments and dyes such as ultramarine and cobalt violet, antioxidants, fluorescent brighteners, and ultraviolet absorbers in appropriate combinations. . The polyolefin resin-coated paper which is advantageously used in the practice of the present invention is produced by extrusion coating a molten polyolefin resin onto a running base paper through a slit die in the form of a film. At that time, it is desirable to activate the base paper surface by corona treatment, flame treatment, etc. prior to melt extrusion coating. The thickness of the coating resin layer is not particularly limited, but it is generally advantageous to have a thickness of about 5μ to 50μ. The side of the polyolefin resin-coated paper on which the silver halide photographic constituent layer is provided has a glossy surface, matte surface, silky 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 that is advantageously used in carrying out the present invention includes low density polyethylene, high density polyethylene,
Examples include homopolymers of olefins such as polypropylene, polybutene, and polypentene, copolymers of two or more olefins such as ethylene-propylene copolymers, and mixtures thereof. ;hereinafter simply referred to as MI) can be used alone or in combination. The base paper for polyolefin resin-coated paper may be ordinary natural pulp paper, synthetic fiber paper, or so-called synthetic paper made of synthetic resin film, but wood pulp such as softwood pulp, hardwood pulp, or mixed softwood and hardwood pulp may be used. Natural pulp paper based on 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 preferably 50 g/m ² to 250 g/m ² . Furthermore, the base paper mainly composed of natural pulp can contain various polymer compounds and additives. For example, starch derivatives, polyacrylamide, polyvinyl alcohol derivatives,
Dry paper strength enhancers such as gelatin, sizing agents such as fatty acid salts, rosin derivatives, dialkyl ketene dimer emulsions, wet paper strength enhancers such as melamine resins, urea resins, and epoxidized polyamide resins, stabilizers, pigments, dyes, A fluorescent whitening agent, latex, inorganic electrolyte, PH adjuster, etc. can be contained in appropriate combinations. In carrying out the present invention, the equipment for applying the undercoating liquid onto the hydrophobic support surface on which the silver halide photographic constituent layer is to be provided includes an air knife coater, a roll coater, a bar coater, a blade coater, and a slide coater. Examples include hopper coaters, gravure coaters, flexogravure coaters, and combinations thereof. Prior to coating, it is desirable to activate the surface of the hydrophobic support by corona treatment, flame treatment, or the like. Various drying devices are used to dry the applied coating liquid, including hot air dryers such as straight tunnel dryers, arch dryers, air loop dryers, and sine curve air float dryers, and dryers that use infrared rays, heated dryers, microwaves, etc. can be given. E Example Next, in order to explain the present invention more specifically,
An example will be described. Example 1 Paper with a basis weight of 160 g/m ² was used as the base paper, and one side of it was coated with 9% by weight titanium oxide and 21% by weight low-density polyethylene for kneading titanium oxide (density
0.918, MI8.5), 45% by weight low density polyethylene (density 0.918, MI5.0), 25% by weight high density polyethylene (density 0.965, MI7.0), resin thickness 30μm
50% by weight low density polyethylene (density 0.918, MI5.0),
50% by weight high-density polyethylene (density 0.965,
After corona discharge treatment on the glossy surface of a resin-coated paper having a matte resin layer with a resin thickness of 30 μm made of MI7.0), the coating liquid listed in Table 1 was applied with an air knife coater, dried with hot air, and then photographed. A support for this purpose was manufactured.

[Table] Next, the following emulsion was coated on the obtained support and dried. 19.2 g of silver chlorobromide orthosensitized with silver nitrate;
A black-and-white emulsion containing 48 g of gelatin, 16 ml of a 12% aqueous formalin solution, and a suitable amount of coating aids to a total weight of 600 g was coated in a multilayer coating with the next protective layer at a coating weight of 75 g/m ² (wet weight). A coating solution containing 30 g of gelatin, 18 ml of a 12% formalin aqueous solution, and an appropriate amount of coating aid to make a total of 400 g was coated in multiple layers as a protective layer of the emulsion at a coating amount of 40 g/m ² (wet weight) and dried to obtain black and white photographic paper. Ta. A portion of the obtained black and white photographic paper was uniformly exposed over the entire surface to obtain an intermediate density, and was treated with a 3-fold dilution of D-72 developer for 20 minutes.
After developing at ℃ for 90 seconds, stopping, fixing, washing with water, and drying, the density unevenness of gray density was determined. Cut the remaining photographic paper into 10cm squares and dry them with D-72 in a bright room.
Develop for 90 seconds with a 3x diluted developer, then scratch the surface of the emulsion side with four nails at 2cm intervals in the vertical and horizontal directions to make a checkerboard pattern, and then scratch the surface with your fingertips under running water for 2 minutes. After rubbing, the percentage of the peeled area of the emulsion layer was determined. The results are shown in Table 2.

〔Processing method〕

Processing temperature 33℃ Color development for 3 and a half minutes, bleach fixing for 1 and a half minutes, washing for 3 minutes [Color developer] Potassium carbonate (monohydrate) 46.0g Anhydrous sodium sulfite 2.0g Potassium bromide 0.5g CD- (Eastman Godatsuk) Color developing agent) 4.5g Sodium hexametaphosphate 0.5g Hydroxylamine hydrochloride 2.0g Fluorescent brightener 0.5g Benzyl alcohol 12ml Diethylene glycol 10ml Bring the total volume to 1 with water, and adjust the pH to 1 with sodium hydroxide.
Adjust to 10.2. [Bleach-fix solution] Ferric complex salt of ethylenediaminetetraacetic acid 56g Disodium salt of ethylenediaminetetraacetic acid 2g Ammonium thiosulfate 60g Anhydrous sodium sulfite 20g Sodium acid sulfite 5g Disodium phosphate 12g Adjust the total amount to 1 with water. F. Effects of the Invention According to the present invention, the adhesion between the emulsion layer and the support is good and no unevenness in the thickness of the emulsion layer occurs.

Claims (1)

[Scope of Claims] 1. In a resin-coated paper-type photographic support in which both sides of paper are coated with a resin capable of forming a film, at least gelatin is added to the resin surface on the side on which the photographic light-sensitive layer is provided, and paraoxygen is added as a preservative. For photography, in which a coating layer containing an ester of benzoic acid is provided in advance, the coating amount of the coating layer is 0.01 to 0.1 g/m ² , and the coating amount of the preservative is 0.2 to 20% by weight based on the coating amount of gelatin. support. 2. The photographic support according to claim 1, wherein the resin capable of forming a film is a polyolefin. 3. The photographic support according to claim 2, wherein the polyolefin is polyethylene.