JPH0254535B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention provides an emulsion copolymer of methyl acrylate and ethyl acrylate in at least one of the photographic layers constituting a photographic light-sensitive material in order to improve the mechanical properties, electrostatic properties and physical properties of the photographic layer. This invention relates to a photographic light-sensitive material containing a polymer (in the present invention, a photographic layer includes a light-sensitive silver halide emulsion layer, an intermediate layer, a protective layer, a filter layer, a back layer,
A general term for anti-halation layer, image-receiving layer, etc.) In general, gelatin or gelatin derivatives are widely used as components of photographic layers of photographic light-sensitive materials, but they have various drawbacks as described below.
For example, gelatin has a high degree of expansion and contraction in response to humidity, so photographic materials coated with gelatin emulsion may curl at low humidity, and the photographic layer can expand and contract significantly due to humidity and heat, resulting in so-called dimensional stability. Furthermore, the physical properties of the photographic layer, such as scratch strength, surface hardness, abrasion resistance, and adhesion to the support, are insufficient. In order to improve these drawbacks, the photographic layer contains glycerin and its derivatives, polyol compounds, sugars, aluminic acid salts, inorganic alkali salts such as potassium nitrate, various activators, and salts of soluble polymers. This had been done before.
Examples of known polymers include salts of polyacrylic acid, salts of polystyrene sulfonic acid, salts of copolymers having ammonium groups, and salts of copolymers of methacrylic acid and methyl methacrylate. However, the use of these known compounds is associated with various disadvantages. In other words, these polymers cause stickiness during storage of photographic light-sensitive materials, and they also dissolve into processing solutions during development processing, thereby affecting the mechanical properties, electrostatic properties, and physical properties of the photographic layer of the finished photographic material. The properties will be very poor. In order to improve the above-mentioned drawbacks, it has been attempted to incorporate aqueous dispersions of polymers (ie, latexes) into the photographic layers. As copolymers used for this purpose, aqueous dispersions of copolymers having carboxylic acid groups are widely used. For example, US Patent No. 2627088, US Patent No. 2491023
The manuscript describes a copolymer of vinylidene chloride, acrylic acid ester, and itaconic acid.
Although these copolymers are effective because they do not have the drawback of being eluted during the development process like the above-mentioned soluble polymer salts, they are still sufficiently satisfactory in terms of improving physical properties, especially curling of photographic materials. isn't it. Therefore, it is an object of the present invention to contain an aqueous dispersion of an acrylic ester copolymer in a photographic layer, thereby eliminating the above-mentioned drawbacks and improving mechanical, electrostatic and physical (especially curling) properties. The object of the present invention is to provide a photographic material with improved properties. In order to achieve this object, the present inventors have conducted intensive research and found that at least one of the photographic layers constituting a photographic light-sensitive material composed of hydrophilic colloids contains:
40-10 parts of methyl acrylate, 60 parts of ethyl acrylate
It has been discovered that the above object can be achieved by incorporating an emulsion copolymer consisting of ~90 parts, and the present invention has been accomplished. Furthermore, the present inventors have discovered that the density of a silver image can be increased by the present invention, and it has also become possible to obtain a photographic light-sensitive material with a low silver content. The aqueous dispersion of the copolymer used in the present invention is
“Experimental Methods of Polymer Synthesis” (WR Sorenson, TW
It can be synthesized by the method described in J. Campbell, translated by Toshio Hoshino and Naoya Yoda, published by Tokyo Kagaku Dojin). The surfactant used in the synthesis of the copolymer used in the present invention can be either nonionic or anionic, but anionic surfactants are preferred because they have less influence on the silver halide emulsion. The amount of the acrylic ester copolymer used in the present invention is 10 to 100% by weight, preferably 20 to 50% by weight, based on the hydrophilic protective colloid. In the present invention, the aqueous dispersion of the copolymer may be added to any layer such as a photosensitive silver halide emulsion layer, an intermediate layer, a protective layer, a filter layer, a back layer, an antihalation layer, an image receiving layer, etc. . Hydrophilic colloids used in the present invention include:
Those commonly used in photographic materials such as lime-treated gelatin, acid-treated gelatin, modified gelatin, and gelatin derivatives can be used. The present invention is applicable to paper-based supports such as baryta-coated paper, document paper, and resin-coated paper, natural cellulose esters such as nitrocellulose, diacetate cellulose, and triacetate cellulose, or polyester, polycarbonate,
It can be applied to any photographic material that uses a synthetic polymer film such as polystyrene as a support. The hydrophilic colloid layer according to the present invention contains various additives, such as color formers that couple with oxidation products of color developing agents such as paraphenylene diamine derivatives to form dyes, ultraviolet absorbers, and optical brighteners. , an antifoggant, a stabilizer, a preservative, a surfactant, a dispersant, a hardening agent, etc. may be included as necessary. The photosensitive silver halide used in the photographic light-sensitive material of the present invention includes various silver halides, namely silver bromide, silver bromide,
Silver iodide, silver chloride, silver chlorobromide, silver chloroiodide, silver bromoiodide, and silver chloroiodobromide can be used. Such photosensitive silver halide may be of the surface latent image type or of the internal latent image type as disclosed in US Pat. No. 2,592,250. Further, as the photosensitive silver halide, a pre-fogged one as disclosed in British Patent No. 723019 can also be used. The photosensitive silver halide may be either a monodispersed emulsion or a polydispersed emulsion in which silver halide grains are dispersed in a hydrophilic colloid solution with a uniform particle size distribution. The silver halide emulsion may be chemically sensitized by various methods. For example, chemically sensitized by aging in the presence of destabilizing sulfur-containing compounds such as allyl thiocyanate, allyl thiourea, thiosulfate, etc. tin compounds as described in the specification, iminoaminomethanesulfinic acid compounds as described in British Patent No. 789823, and noble metal compounds such as gold, platinum,
It may also be sensitized with reducing agents such as palladium, iridium, ruthenium, and rhodium compounds.
Also, U.S. Patent Nos. 2531822 and 2533990, British Patent Nos. 920637, 940041, 945340,
Polyoxyalkylene compounds described in French Patent No. 991608 and Belgian Patent No. 648710, and amino-N- compounds described in French Patent No. 1498724.
It may be chemically sensitized with an oxide onium compound or the like. The photosensitive silver halide emulsion used in the present invention may be sensitized with an optical sensitizing dye.
Infectious agents for this purpose include cyanines, merocyanines, complex (trinuclear or tetranuclear) merocyanines, complex (trinuclear or tetranuclear)
Cyanines, holoporacyanines, styryls, hemicyanines, oxonols, hemioxonols, etc. can be used. In the present invention, the photosensitive layer may be one layer or two or more layers. In case of 2 or more layers,
A non-photosensitive intermediate layer may also be provided between the photographic photosensitive layers. Next, the present invention will be explained based on examples, but of course the present invention is not limited to the examples. Example 1 An aqueous dispersion of an acrylic ester copolymer with varying composition ratios of methyl acrylate and ethyl acrylate was prepared, and this was mixed with alkali-treated gelatin.
It was added to a silver chlorobromide emulsion containing 7.5%. The amount added was such that the copolymer component was 50% of the gelatin. The thus obtained silver halide emulsion was coated onto a resin-coated paper support using an extrusion coating method so that the gelatin content was 6.5 g/m ² and the silver content was 1.2 g/m ² to prepare a sample. did. This sample is a circular sample with a diameter of 100 mm,
After 2 hours in an atmosphere of 24° C. and 20% RH, the degree of curl of each sample was measured. The results obtained are shown in Table-1. In the measurement, curl in the emulsion direction (the emulsion is on the inside) is defined as +, curl in the opposite direction as -, and the amount of curl (curl degree) is expressed as 1/R. R is the radius of curvature of the curve in meters.

【table】

[Table] From the results in Table 1, the samples to which the acrylic acid ester copolymer was added (sample Nos. 2 to 7) had a low degree of curl, and the methyl acrylate copolymer of the present invention, especially 40 to 10
sample to which an acrylic ester copolymer consisting of 60 to 90 parts of ethyl acrylate was added (Sample No. 2)
Items 5) to 5) had a low degree of curl, indicating that the acrylic ester copolymer of the present invention is effective in preventing curling. Example 2 Each sample in Example 1 was exposed to light that would give a sufficient maximum density through development, and developed at 20°C for 90 seconds with a 1:2 dilution of the developer shown below. After fixing with fixer at 20℃ for 5 minutes,
Rinse with running water for 10 minutes. Next, each sample was dried with warm air at 50°C, and the blackening density of each sample was measured using a Macbeth densitometer (RD-519). The results obtained are shown in Table-2. Developer solution Metol 3.1g Hydroquinone 12.5g Sodium sulfite (anhydrous) 45g Sodium carbonate (anhydrous) 67.5g Potassium bromide 1.9g Add water to make 1.

【table】

[Table] From the results in Table 2, the samples to which the acrylic ester copolymer was added (sample Nos. 2 to 7) had a high maximum concentration, especially the methyl acrylate 40 to 10 of the present invention.
sample to which an acrylic ester copolymer consisting of 60 to 90 parts of ethyl acrylate was added (Sample No. 2)
It can be seen that samples 5) to 5) have a high maximum concentration.

Claims (1)

[Claims] 1. An emulsion copolymer consisting of 40 to 10 parts of methyl acrylate and 60 to 90 parts of ethyl acrylate is contained in at least one of the photographic layers constituting a photographic light-sensitive material made of a hydrophilic colloid. A photographic material characterized by containing: 2. The photographic material according to claim 1, wherein the hydrophilic colloid is gelatin or/and a gelatin derivative.