JPH02289845A - Photographic substrate and manufacture of the same - Google Patents

Abstract

PURPOSE:To obtain superior curling resistance by using a low-density polyethylene for a first resin layer nearest to the base paper of mulilayer structure and a high-density polyethylene for at least one of the outer layers. CONSTITUTION:The resin layers of the multilayer structure are formed on the side reverse to the side of photographic emulsion layers, and the low-density polyethylene is used for the first resin layer nearest to the base paper in an amount of >= 50 wt.%, and at least one of the outer layers contains the high- density polyethylene in an amount of >= 75 wt.%, thus permitting the obtained photographic substrate to maintain a curling level required for the quality level, while reducing an amount of resin to be coated, and to improve adhesion between the base paper and the resin, and to be manufactured under the stable conditions of the extrusion fluidity of the resin.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a photographic support and a method for producing the same.

[Background of the invention]

BACKGROUND ART Conventionally, so-called baryta paper, in which one side of the paper is coated with a baryta layer mainly composed of barium sulfate, has been used as a photographic support. In recent years, as photographic processing speeds have increased, paper called resin-coated paper, which is a waterproof support made by coating both sides of base paper with thermoplastic synthetic resins such as polyethylene or polypropylene, has become increasingly popular. It has become possible to do so. Generally, such resin-coated paper is produced by melting and extruding the thermoplastic synthetic resin using an extruder, applying the film to both sides of the base paper while it is still hot, and applying the film to both sides of the base paper using a nip consisting of a cooling roll and, for example, a rubber muzzle. It is manufactured by pressing resin onto paper.

The photographic support with the above structure has less expansion and contraction due to changes in humidity than normal baryta paper, but when a photosensitive emulsion whose main binder is a polymer such as gelatin is coated on the surface, Curling occurs because the emulsion layer expands and contracts significantly as the humidity changes.

In particular, if the emulsion is dried excessively after it has been applied, or if the resulting photographic paper or the photographic paper after processing is left at low humidity, such as 20% relative humidity, curling with the emulsion side inward may occur. arise.

The occurrence of this curl not only reduces work efficiency and yield during the production of photographic paper or during enlarging and printing operations, but also makes it difficult to stack the photographic papers and paste them into albums.

Regarding the thickness of the thermoplastic synthetic resin film applied to the resin-coated paper, product standards are often set for the side to which photographic emulsion is applied, but the back side, which is the other side, is not so important and is generally laminated. The thickness of the film can be changed freely.

However, since changing the thickness of the laminate on the back side changes the curl of the product, conventionally the thickness of the laminate on both the front and back sides has been matched in order to maintain consistent product quality.

On the other hand, high-density polyethylene is characterized in that it is extremely effective for improving curl resistance, as described in Japanese Patent Publication No. 48-9963. Taking advantage of this property, by applying a low-density polyethylene resin on the side where the photosensitive material is coated and a high-density polyethylene resin on the back side, the laminated paper before emulsion coating is made with the emulsion coated side on the outside. Try to give it curls. When a photosensitive emulsion is coated on the laminated paper thus obtained and dried, the curl becomes balanced due to drying shrinkage of the photosensitive emulsion layer.

That is, curl resistance can be increased by increasing the blending ratio of high-density polyethylene. Furthermore, even if the amount of lamination on the back side is reduced, the curl required for quality can be maintained by increasing the blending ratio of high-density polyethylene on the back side. That is, manufacturing costs and transportation costs can be reduced while maintaining quality.

[Problem to be solved by the invention]

However, if the blending ratio of high-density polyethylene increases too much, the fluidity of the resin during extrusion becomes unstable, and problems arise such as poor adhesion between the paper base and the resin layer, so there is a limit to the blending ratio of high-density polyethylene. Therefore, a photographic support with excellent curl resistance could not be obtained.

[Means to solve the problem]

The present invention has been made to solve these problems. The present invention provides a photographic support which is coated with a polyolefin layer by extrusion coating a molten polyolefin resin on both sides of a base paper, in which the resin layer on the side opposite to the side on which the photographic emulsion layer is provided has a multilayer structure, and the multilayer structure Low density polyethylene is added to the first resin layer closest to the base paper.
This is achieved by a photographic support characterized in that at least one of the layers outside of polyethylene is provided with a layer containing 75% by weight or more of high-density polyethylene.

In addition, in a method of manufacturing a photographic support coated with a polyolefin layer by extrusion coating molten polyolefin resin on both sides of base paper, a multilayer structure is created by coextrusion coating of the resin layer on the side opposite to the side on which the photographic emulsion layer is provided. , the first resin layer closest to the base paper of the multilayer structure contains 50% by weight or more of low-density polyethylene, and at least one of the outer layers contains high-density polyethylene 7.
This is achieved by a method for manufacturing a photographic support characterized in that the content is 5% by weight.

If the amount of low density polyethylene in the first resin layer closest to the base paper constituting the multilayer structure is less than 50% by weight, the adhesiveness between the resin layer and the base paper layer will decrease. If the high-density polyethylene content of the outer layer containing the highest concentration of high-density polyethylene is less than 75% by weight, the ratio of high-density polyethylene to the entire backing resin layer is the same. This is not much different from the case of mixed single-layer extrusion coating, and the effects of the present invention are not fully exhibited.

Furthermore, as the content of high-density polyethylene in the layer containing the highest concentration of high-density polyethylene further increases to 80% by weight, 90% by weight, and 100% by weight, the effects of the present invention are more significantly exhibited. .

In addition, it is preferable from the viewpoint of curl improvement that the high density polyethylene is concentrated in a layer containing a high concentration of 75% by weight or more, and at least 50% of the high density polyethylene contained in the multilayer structure is made of high density polyethylene. It is desirable to include it in the containing layer.

Extrusion lamination methods for forming multiple layers of resin include sequential coating and coextrusion coating, but coextrusion coating is desirable in order to create ultrathin layers for the above-mentioned purpose.

During coextrusion coating, extruding three or more layers and arranging a layer containing a high concentration of high density polyethylene on the inside has the effect of reducing neck-in.

In the present invention, the polyolefin resin includes homopolymers such as low density polyethylene, medium density polyethylene, high density polyethylene, polypropylene, polybutene, polypentene, etc., or copolymers consisting of two or more olefins such as ethylene-propylene copolymer. combinations and mixtures thereof.

In the present invention, the low density polyethylene used on the back side of the photographic support opposite to the side on which the photographic emulsion layer is provided is:
It has a density of 0.915 to 0.930 g/cm' and is usually produced by a high-pressure method. In addition, the high density polyethylene used for the back side has a density of 0.95
It has a value of 0 g/an3 or more and is usually produced by a low-pressure method or a medium-pressure method. Particularly preferable high-density polyethylene has a density of 0.955 to 0.95% from the viewpoint of coextrusion characteristics, curl improvement effect, etc. 9 7 0 g/a
m”.

Further, within the scope of the present invention, these polyolefin resins having various densities and melt viscosity indexes (melt index: hereinafter simply referred to as Ml) may be used singly or in combination of two or more thereof. can. For example, as the first resin layer on the back side, the density is 0. 9
1 8 g/an', M 1 = 7.0, density 0.967 g/cm 3 as the second resin layer, M I = 6.
It is possible to use resins with different densities and Ml, such as those with 0.

The side of the photographic support of the present invention on which the photographic emulsion layer is provided, that is,
The resins mentioned above can also be used as the resin constituting the front side. It is advantageous to contain 7.5 to 25% by weight of a rutile-type or anatase-type titanium dioxide pigment in the polyolefin resin layer on the front side in order to improve the sharpness of the printed image.

Examples of titanium dioxide pigments suitable for photographic supports include Japanese Patent Publications No. 42296/1986, 37304/1982, 3430/1980, 56118/1980, 108849/1984, and 58/198. -7630, JP 58-22014, JP 59-1544, JP 59-121329, JP 59-464550,
JP-A-59-215334, JP-A-61-10363
The material described in No. 5 can be contained.

In addition to titanium dioxide pigments, the resin layer on the front side also contains white pigments such as zinc oxide, talc, and calcium carbonate, fatty acid amides such as stearic acid amide and arachidic acid amide, zinc stearate, calcium stearate, and stearic acid. Aluminum, magnesium stearate, zinc palmitate, zinc mystiphosphate, calcium palmitate, and other fatty acid metal salts, hindered phenol, hindered amine, phosphorus, sulfur, and other antioxidants, cobalt blue, ultramarine blue, cerulean blue, It is preferable to add an appropriate combination of various additives such as blue pigments and dyes such as phthalocyanine blue, magenta pigments and dyes such as cobalt violet, fast violet, and manganese violet, fluorescent brighteners, and ultraviolet absorbers. In addition, methods for incorporating titanium dioxide pigments and their additives are described in the above-mentioned publication specifications and Japanese Patent Application Laid-open No. 6
This can be carried out by any method such as those described or exemplified in JP-A No. 0-11841, JP-A-60-75832, JP-A-60-181131, and the like.

In addition, each resin layer on the back side of the multilayer structure of the photographic support in the present invention also contains white pigments, fatty acid amides, fatty acid metal salts, various antioxidants, coloring pigments, etc., in the same way as those contained in the front resin layer. Various additives such as dyes, fluorescent whitening agents, and ultraviolet absorbers can be contained in appropriate combinations.

In particular, it is preferable to contain a fatty acid metal salt in an amount of several ppm to 0.5 weight 96 and an antioxidant described or exemplified in JP-A-60-11847 in an amount of several ppm to 1000 ppm. In addition, it is particularly preferable to contain a large amount of antioxidant in the outer layer of the multilayer structure in order to improve adhesion to the base paper.
It is preferable to have a large amount contained in the outermost layer because it improves mold releasability from the cooling roll.

The photographic support of the present invention is manufactured by a so-called extrusion coating method in which a heated and molten polyolefin resin is cast onto a moving filter paper substrate, and usually both sides of the support are coated with the resin.

At this time, the resin layer on the back side is extrusion coated in a multilayer structure as described above. On the other hand, the resin on the front side may have a single layer or a multilayer structure. Furthermore, it is preferable to subject the base paper to a corona discharge treatment before coating the base paper with the resin. The surface of the emulsion side of the photographic support is glossy or has a gloss level that does not affect the gloss of the surface of the photographic paper when it is made into photographic paper.
It has a finely rough surface, a matte surface, a grain surface, etc. as described in No. 07, and the back surface is usually a matte surface, and if necessary, the front surface or both the front and back surfaces are subjected to activation treatment such as corona discharge treatment or flame treatment. can be administered. Further, after the activation process, a subbing process as described in JP-A-61-84643 can be performed.

Further, the thickness of the resin layer on each of the front and back sides of the photographic support in the present invention is not particularly limited, but is generally 10μ to 50μ.
Extrusion coating to a thickness of approximately μ is advantageous, but from the viewpoint of the effects of the present invention, that is, improvement of the physical properties of the shell and cost, the total thickness of the back side resin layer is thinner than the thickness of the front side resin layer. It is advantageous for the two to be equal.

The base paper used in the present invention may be any natural pulp paper mainly composed of ordinary natural pulp or a mixed paper made of natural pulp and synthetic fibers. As a substrate, it is economical to use an excellent photographic support that has good curl physical properties, so it is easy to run and handle during the development process of photographic paper containing the support, and prints with less curl can be obtained. Natural pulp paper (
(hereinafter simply referred to as base paper) is particularly preferably and advantageously used.

Valps constituting the base paper preferably used in carrying out the present invention include JP-A-58-37642 and JP-A-60-37642.
No. 67940, JP-A-60-69649, JP-A-61
It is advantageous to use appropriately selected natural pulps such as those described or exemplified in No. 35442.
Synthetic pulp and synthetic fibers other than natural pulp may be used if necessary.

Natural pulp is subjected to conventional bleaching treatments such as chlorine, hypochlorite, and chlorine dioxide bleaching, as well as alkali extraction or alkali treatment and, if necessary, oxidative bleaching treatment using hydrogen peroxide, oxygen, etc., and combinations thereof. Wood bulps of softwood pulp, hardwood pulp, softwood hardwood mixed pulp are advantageously used, and also kraft pulp,
Various materials such as sulfite pulp and soda pulp can be used.

The base paper preferably used in the practice of the present invention can contain various sizing agents and polymer compounds when preparing the paper stock slurry.

Sizing agents that can be advantageously included in the base paper preferably used in the practice of the present invention include fatty acid metal salts and/or
and fatty acids, alkyl ketene dimers, alkenyl or alkyl succinic anhydrides, JP-A-54-147211
Epoxidized higher fatty acid amide described in JP-A No. 1987-
Examples include organic fluoro compounds described in No. 109343.

Sizing agents that can be advantageously incorporated into the base paper preferably used in the practice of the present invention include fatty acid metal salts or/ Examples include alkyl ketene dimer or a combination sizing agent of an alkyl ketene dimer and an epoxidized higher fatty acid amide, which are fixed to the bulb with or without a fatty acid and a water-soluble aluminum salt. The fatty acid metal salt and/or fatty acid preferably have 12 to 22 carbon atoms,
The amount added is 0.0% per bone dry weight of pulp. 5-4.
A range of 0% by weight is preferred.

In addition, the amount of water-soluble aluminum salt added as needed is 1/20 to 4 times the solid weight of the sizing agent.
The range of /1 is particularly preferred, and the range of 1/10 to 1/1 is particularly preferred. Further, as the alkyl ketene dimer, one having an alkyl group having 8 to 30 carbon atoms, preferably 12 to 18 carbon atoms is preferable. Alkyl ketene dimers are usually commercially available as emulsions thereof, and specific examples include Acopel 360XC manufactured by Dick Hercules. The amount added is preferably in the range of 0.2 to 4.0% by weight based on the absolute dry weight of the pulp as the alkyl ketene dimer content.

Examples of polymer compounds that can be advantageously incorporated into the base paper preferably used in the practice of the present invention during the preparation of the paper stock slurry include cationic wet paper strength agents, cationic, anionic or amphoteric paper strength agents. As the cationic wet paper strength agent, polyamine polyamide epicurethane resin is preferable, and the amount added is in the range of 0.05 to 4.0% by weight, particularly 0.15% by weight, based on the bulk dry weight.
A range of 1.5% by weight is preferred. A specific example is Kaimen 557H manufactured by Dick Hercules ■. Examples include Kaimen S-25 and Evinox P-130.

Examples of cationic, anionic or amphoteric paper strength enhancers include cationic starch described or exemplified in Japanese Patent Publication No. 60-17103, cationic polyvinyl alcohol described or exemplified in Japanese Patent Application No. 6249699, and cationic polyvinyl alcohol described or exemplified in Japanese Patent Application No. 1983-1983. -185432, cationic polyacrylamide described or exemplified in JP-A-57-197539, anionic polyacrylamide described or exemplified in JP-B No. 62-23119, JP-B No. 62-31118, JP-A-61-37613 , amphoteric polyacrylamide described or exemplified in JP-A-59-31949;
Examples include vegetable galactomannans described or exemplified in No. 9-125731. The addition amount thereof is preferably in the range of 0.05 to 8% by weight, particularly preferably in the range of 0.15 to 4% by weight, based on the dry weight of the pulp.

In addition, the base paper preferably used for carrying out the present invention includes:
Various additives can be included when preparing the paper stock slurry. Fillers include clay kaolin, calcium carbonate, barium sulfate, magnesium silicate, titanium oxide, etc. pH regulators include caustic soda, soda carbonate, etc.
As a coloring pigment, a coloring dye, and a fluorescent whitening agent, JP-A-54-
No. 147033, Japanese Patent Application No. 61-37555, Japanese Patent Application No. 1983
The materials described or exemplified in No. 3-96516 may be contained in appropriate combinations.

Various water-soluble polymers, antistatic agents, and additives can be added to the base paper preferably used in the practice of the present invention by spraying or tab size pressing. Water-soluble polymers include starch polymers, polyvinyl alcohol polymers, gelatin polymers, polyacrylamide polymers, and cellulose polymers as described or exemplified in Japanese Patent Application No. 63-96516. Alkali metal salts such as sodium chloride and potassium chloride, alkaline earth metal salts such as calcium chloride and barium chloride, colloidal metal oxides such as colloidal silica, described in JP-A-58-82242. Or as examples of organic antistatic agents, latexes, emulsions, petroleum resin emulsions, styrene-acrylic acid monoacrylate copolymers, styrene-acrylic acid monobutadiene copolymers, ethylene-vinyl acetate copolymers, styrene-vinyl acetate copolymers, etc. Latex such as maleic acid-acrylic acid ester copolymer, pigments such as clay, kaolin, talc, barium sulfate, titanium oxide, etc., pH regulators such as hydrochloric acid, phosphoric acid, citric acid, caustic soda, soda carbonate, etc. It is advantageous to contain a suitable combination of additives such as colored pigments, colored dyes, and optical brighteners.

For the production of the base paper preferably used in the practice of the present invention, commonly used paper machines such as a Fourdrinier paper machine and a circular net paper machine are used.
It is advantageous to employ suitable papermaking methods, such as those described or exemplified in JP-A-60240 and JP-A-61284762.

There are no particular restrictions on the thickness of the base paper, but after making the base paper,
Preferably, the base paper is calendered as described or exemplified in No. 6397, and its basis weight is 40 g/
Those with rrf to 250 g/rrf are preferred.

The photographic support in the present invention can be coated with various back coat layers for antistatic purposes, curl prevention, and the like. In addition, for the back coat layer,
No. 20, Special Publication No. 57-9059, Special Publication No. 57-539
No. 40, Japanese Patent Publication No. 58-56859, Japanese Patent Publication No. 59-21
Inorganic antistatic agents, organic antistatic agents, hydrophilic binders, latexes, curing agents, pigments, surfactants, etc. described or exemplified in No. 4849, JP-A No. 58-184144, etc. can be contained in appropriate combinations. .

The photographic support in the present invention is coated with various photographic constituent layers, and is used for color photographic paper, black and white photographic paper, typesetting photographic paper, copying photographic paper, reversal photographic material, silver salt diffusion transfer. It can be used for various purposes such as for negatives and positives, and for printing materials. For example, silver chloride, silver bromide, silver chlorobromide, silver iodobromide, and silver chloroiodobromide emulsion layers can be provided. A color coupler is contained in the silver halide photographic emulsion layer,
Multiple silver halide constituent layers can be provided.

Further, a silver salt diffusion transfer image-receiving layer can be provided by containing physical development nuclei. As the binder for these photographic constituent layers, in addition to ordinary gelatin, hydrophilic polymeric substances such as polyvinyl pyrrolidone, polyvinyl alcohol, and polysaccharide sulfate ester compounds can be used. Also,
The photographic constituent layer described above may contain various additives.

For example, sensitizing dyes such as cyanine dyes and merocyanine dyes; chemical sensitizers such as water-soluble gold compounds and sulfur compounds; antifoggants or stabilizers such as hydroxy monotriazo-pyrimidine compounds and mercapto heterocyclic compounds; Hardeners include formalin, vinyl sulfone compounds, and aziridine compounds. Coating aids include benzene sulfonate and sulfosuccinate salts. Anti-staining agents include dialkylhydroquinone compounds. Other optical brighteners and sharpness agents. An improving dye, an antistatic agent, a pH adjuster, a fogging agent, and further a water-soluble iridium, a water-soluble rhodium compound, etc. can be contained in appropriate combinations during the production and dispersion of silver halide.

The silver halide photographic material according to the present invention can be used for exposure, development, and stopping as described in "Photographic Light-sensitive Materials and Handling Methods" (Kyoritsu Shuppan, written by Goro Miyamoto, Photographic Technology Course 2) according to the photographic material. , fixing, bleaching, stabilization, etc. Multilayer silver halide color photographic materials that undergo one-bath bleach-fixing treatment after color development are particularly suitable for CD-III, CD-
Processing can be carried out with any color developer containing any main ingredient, such as IV (the above two compounds are trade names of Kodak Co.) and droxychrome (trade name of May and Baker Co.).

A developing solution containing such crude drugs may contain a development accelerator such as benzyl alcohol, thallium salt, or phenidone. It is also possible to process with a developer substantially free of benzyl alcohol. Also useful is a one-bath bleach-fix solution containing metal salts of aminobolycarboxylic acids (for example, ferric complex salts such as ethylenediaminetetraacetic acid and propylenediaminetetraacetic acid), and the fixing agents include sodium thiosulfate and ammonium thiosulfate. etc. are useful. Such a one-bath bleach-fix solution may contain various additives. For example, desilvering accelerators (e.g., U.S. Pat. No. 3,512
, mercaptocarboxylic acids described in Belgian Pat. A combination of various compounds such as aluminum sulfate, potassium alum, surfactants, etc. can be contained in combination. Also, such single bath bleach-fix solutions can be used at various pHs, but a useful pH range is from pH 6.0 to 8.0.

〔Example〕

Example 1 Tsuboffi170g/rr? Use the photographic base paper of
A backwood nh layer having a matte surface was formed by melt coextrusion coating on the corona-treated surface at 0° C. in the coating amount shown in Table 1 (one layer of extrusion coating for black ■ to ■).

Next, the surface was corona treated and anatase type titanium oxide 5
0 weight H. Part t, low density polyethylene (density 0.918g
/c+++', MI9) 47.5 parts by weight, 20 parts by weight of a master batch consisting of 2.5 parts by weight of zinc stearate, high density polyethylene (density 0.96 g/cm3, MI
7) 25 parts by weight, low density polyethylene (density 0.918
g/cm3, MI5) at a resin temperature of 3.
A surface resin layer with a glossy surface was formed by melt extrusion coating at 20° C. with a coating amount of 30 g/rrf.

(Leaving space below) Evaluation method Cut the curled sample into 3 cm in the flow direction and 10 cm in the width direction, and after 24 hours at a temperature of 25°C and a humidity of 65% RH, place it on a horizontal table with the center part touching the ground. The length of the end was measured.

Curl towards the emulsion side was defined as plus (+), and curl towards the back side was defined as minus (-).

When the polyethylene coating layer was slowly peeled off from the adhesive paper substrate, the condition was sensory evaluated on the following four scales.

A: The entire peeled surface of the paper base lacks luster and is fluffy.

B: Some glossy areas are seen on the peeled surface of the paper base.

C: Considerable glossy areas are seen on the peeled surface of the paper base.

D2: The entire peeled surface of the paper substrate is glossy and free of fuzz.

Of the four classes mentioned above, those given a rating of Δ or B are considered to be in a practically satisfactory state.

Extrusion characteristics! The laminate width of the sample was measured at 50 cm intervals to evaluate necking and flow instability, so-called surging or draw resonance.

The results are shown in Table 2.

(Left below) Comparison of samples ■, ■ and comparison of ■, ■, ■ shows that when the coating amount ratio of high-density polyethylene and low-density polyethylene is the same, the second resin layer is made of high-density polyethylene alone in two-layer coextrusion. It can be seen that by blending and further concentrating high-density polyethylene in the second resin layer, the amount of resin applied can be reduced while maintaining the curl level.

When laminated with high-density polyethylene alone, as in sample ①, the resin weight reduction effect becomes extremely large. but,
The neck-in increases, the laminate width becomes unstable, and the extrusion characteristics deteriorate.

Furthermore, the adhesion between the paper base and the resin layer is also poor, making it unsuitable for practical use.

Example 2 The same procedure as in Example 1 was carried out except that Table 1 of Example 1 was replaced with Table 3.

(Margin below) Note 3: The resins used are the same as Note 1 in Table 1.

Table 4 shows that when the content of low density polyethylene in the first resin layer is less than 50%, the adhesion to the base paper becomes unstable.

Example 3 The same procedure was carried out as in Example 1 except that Table 1 was replaced with Table 5.

(Margin below) Note 4 Same as the prototype in Table 3.

No. table No. table Note 6 = Same as the prototype in Table 5.

Note 5 = Low density in the table: Density 0.918 g/an", MI5 Low density polyethylene High density: Density 0.967 g/am", MI
7 high-density polyethylene blend: 1:1 weight ratio of both
The mixture results are shown in Table 6.

As is clear from Table 6, even in a three-layer structure, when a 100% high-density polyethylene layer is present, the curl balance is maintained even with a low coating amount of backing resin. In addition, NQ (Q}, 0, O, 0 with a high-density polyethylene layer as an intermediate layer)
It can also be seen that the neck-in is smaller than that of NαO.

Example 4 The same procedure was carried out as in Example 1 except that Table 1 was replaced with Table 7.

(Margin below) No. table Note 7 = The amount of coating of the first resin layer and the second resin layer is equal.

The resin used for this purpose is low density polyethylene with a density of 0.92g/
aI+3, M■3, high density polyethylene has a density of 0.95
5 g/am', M I 3.

The results are shown in Table 6.

No. table Note 8 = Same as Table 7 Prototype.

For each sample-@-Q, the total weight ratio of high-density polyethylene and low-density polyethylene in the first resin layer and the second resin layer is 1.
However, when the high density polyethylene content of the second resin layer is 75% by weight or more, the curl level is maintained.
It can be seen that the amount of resin applied can be efficiently reduced.

Example 5 A prototype was produced in the same manner as in Example 1.

For A-1-A-7, change to Table 1, and coat the first resin layer with 100% low-density polyethylene and the second resin layer with the compounding ratio listed in Table 9 so that the coating weight of both layers is equal. Then, the curl value was -2.4mm after changing both the back resin and
The coating amount was determined.

For B-1 to B-7, one layer of extrusion coating is applied with a composition corresponding to the weight ratio of high-density polyethylene and low-density polyethylene in the total of the first resin layer and second resin layer of A-1 to A-7. The same procedure was performed except that the layers were formed. 9th result
Shown in the table.

Note that the resins used were the same as in Example-1.

From Table 9, when the content of high-density polyethylene in the second resin layer exceeds 75% by weight, coextrusion coating allows the curling to be particularly noticeable while maintaining the curl level if high-density polyethylene is intensively used in the second resin layer. It can be seen that the amount of resin applied can be reduced.

Example 6 Paper making of base paper for support Material 1 of softwood sulfite pulp and hardwood kraft pulp
Canadian Standard Freeness 31 to 1 Mixture
Co-beat to 0 ml, and use a Fourdrinier paper machine with the following composition to make 17.
A paper of 0 g/rrf was made.

(Numbers in the formulation indicate parts by weight.) Pulp 100 cationic starch 2 anionic polyacrylamide resin 0.5 alkyl ketene dimer emulsion
0.4 (as ketene dimer content) Polyamide polyamine epichlor 0.4 Hydrin resin After passing through the main dryer, add 35g of the following blended impregnating solution /
It was impregnated with RD, dried with an after-dryer, smoothed with a machine calender, and then wound up.

(Numbers in the formulation indicate parts by weight) Carboxy-modified polyvinyl alcohol 3 Diaminostilbenzyl sulfonate type fluorescent brightener 0.05 Blue dye
0.002 salt
2 Add water
100 Production of resin-coated paper-type photographic support The paper web was pulled out from the original roll and the back side was corona-treated, Sample C≧
and high-density polyethylene (density 0.96 g/a
A 1:1 mixture of 1:1 mixture of 30 g/n'', M I 7) and low density polyethylene (density 0.92 g/an3, M I 5) was applied to the corona-treated surface at a resin temperature of 320°C in an amount of 30 g.
/A A back resin layer having a matte surface was formed by melt extrusion coating.

As sample ◎, high density polyethylene (density 0.96 g/on!, M I 7) and low density polyethylene (density 0.92 g/cm3,
A coating amount of a 1:1 mixture of M 15) was 11 g/%, and high density polyethylene (density 0.96 g/an) was used as the second resin layer.
", M I 7) was applied in a coating amount of 11 g/n on the corona-treated surface by melt coextrusion coating to form a back resin layer also having a matte surface.

The surface was then corona treated and treated with 50 parts of rutile titanium oxide, low density polyethylene (density 0.918 g/an'',
M I 9) 20 parts of a masterbatch consisting of 50 parts, high density polyethylene (density 0.96 g/an", M
l? ) 30 parts, low density polyethylene (density 0.91L
A mixture of 50 parts of 8g/cs3, Mi5) was heated to a resin temperature of 32
Coating amount 30g/rr at 0℃? A surface resin layer having a glossy surface was formed by melt extrusion coating.

Further, the back surface was subjected to corona treatment, and a back coat coating liquid having the following composition was applied and dried.

The amount of application is 3g/rr moisture? It is.

(Numbers in the formulation indicate parts by weight) Styrene maleic anhydride copolymer Alkaline hydrolyzate of 4 (as a 25% liquid) Colloidal silica (20%
% liquid) 50 styrene acrylic latex
1 (as a 30% liquid) Compound with an effective number of epoxy groups of approximately 2.5 0.252-Ethylhexyl sodium sulfosuccinate surfactant Add 0.01 water 100 Then corona-treat the surface and add 1% by weight of gelatin A subbing liquid solution was applied and dried using an air knife coater, and the areas with incorrect resin coating amount present on both sides of the resulting resin-coated paper-type photographic support were cut into slits, and the normal areas were wound up.

Manufacture of silver halide color photographic light-sensitive material 45 days after manufacturing the resin-coated paper-type photographic support described above, the following layers were sequentially coated from the support side, and silver halide color photographic light-sensitive material samples were prepared. Created.

Layer 1...1.2g/m gelatin, 0.32g/rr
f (in terms of silver, the same applies hereinafter) blue-sensitive chlorobromide emulsion (silver bromide content 90 mol%, average grain size 0.6 μm), 0.50
g/rrf of dioctyl phthalate. 0.8
A layer containing 0 g/n of yellow coupler of structural formula (I).

Layer 2...0.7 g/rrf of gelatin, 8/a of water-soluble dye of structural formula (II) and 4 mg/rd of structural formula (
m) an intermediate layer consisting of a water-soluble dye;

H O NHCHJSO3N! NH O OH CH, So, N* CI Layer 3...1.25 g/rrf gelatin 0.22 g green-sensitive silver bromide emulsion (silver bromide content 5Qa+ol%, average grain size 0.4 μm), 0 A layer containing 0.62 g of a magenta cobbler of formula 1 dissolved in .30 g of dioctyl phthalate.

Layer 4: Intermediate layer consisting of 1.2 g/% gelatin.

Layer 5...1.4g/rrf gelatin, 0.20g/
A red-sensitive silver chlorobromide emulsion (silver bromide content 50IIIO1
%, average particle size {). 4 μm), a layer containing 0.45 g/rrf of cyan coupler of structure (V) dissolved in 0.20 g/rrf of dioctyl phthalate.

CsH II (+1 CI layer 6...1.0 g/rrf gelatin and 0.20 g
0.30 g/nf dissolved in dioctyl phthalate/
A layer containing an ultraviolet absorber having the structural formula (Vl) of d.

Oil Layer 7: A layer containing 0.5 g/rd of gelatin.

As a hardening agent, sodium 2,4-dichloro-6-hydroxy-s-triazine was added to layers 2, 4 and 7 in an amount of 0.012 g per 1 g of gelatin, respectively.

The silver halide color photographic materials thus obtained were cut and subjected to the following treatments.

Processing steps (33°C) Color development 3 minutes 30 seconds Bleach-fixing 1 minute 30 seconds Washing with water 3 minutes drying 60-80'C I minutes 30 seconds The composition of each processing solution is as follows.

[Color developer]

Pure water 8 0 0 [[+
Hydroxyamine 1 sulfate 2.0g Potassium bromide 1.5g Sodium chloride
1, Qg sulfite power 1 strength
2, Og triethanolamine 2.
0gN=ethyl-N-β-methanesulfonamidoethyl-3-methyl-4 Aminoaniline sulfate 4.5g1-hydroxyethylidene-1,1-diphosphonic acid (60% aqueous solution) 1.5ml Potassium carbonate 32gWhile BB
(50% aqueous solution) 2ml (fluorescent brightener,
(Manufactured by Sumitomo Chemical Industries, Ltd.) Add pure water to make 11 and 20% potassium hydroxide or 10%
Adjust the pH to 10.1 with dilute sulfuric acid.

[Bleach-fix solution]

Pure water 550ml Iron(III) ethylenediaminetetraacetate Ammonium 65g Ammonium thiosulfate 85g Sodium bisulfite
10g sodium metabisulfite
2g ethylenediaminetetraacetic acid-2-sodium 20
g Sodium bromide Add 10g of pure water to make 1 liter, and dilute with aqueous ammonia or dilute sulfuric acid p}{=7.
Adjust to 0.

Then, after aging at 20° C. and 65% RH for 24 hours, Example 1
Curl was measured in the same manner as above.

The curl values are -2.1m++ and -2. This shows that the amount of backing resin can be reduced while maintaining the curl level according to the present invention.

〔Effect of the invention〕

According to the present invention, it is possible to maintain a curl level required as a quality level while reducing the amount of resin applied, and to obtain a photographic support with good adhesion between the base paper and the resin. In addition, such a good photographic support can be produced in a state where the extrusion fluidity of the resin is stable.

Claims (1)

[Scope of Claims] 1) In a photographic support which is coated with a polyolefin layer by extrusion coating a molten polyolefin resin onto a base paper surface, the resin layer on the side opposite to the side on which the photographic emulsion layer is provided has a multilayer structure. , the first resin layer closest to the base paper surface of the multilayer structure contains 50% by weight or more of low density polyethylene,
A photographic support, comprising at least one layer containing 75% by weight or more of high-density polyethylene among the outer layers. 2) The photographic support according to claim 1, wherein the content of the high-density polyethylene is 90% by weight or more. 3) In a method of manufacturing a photographic support covered with a polyolefin layer by extrusion coating a molten polyolefin resin on the base paper surface, a multilayer structure is created by coextrusion coating the resin layer on the side opposite to the side on which the photographic emulsion layer is provided. The first resin layer closest to the base paper of the multilayer structure contains 50% by weight or more of low-density polyethylene, and at least one of the outer layers contains 75% by weight or more of high-density polyethylene. A method for producing a photographic support, characterized in that: 4) The method for producing a photographic support according to claim 3, wherein the content of the high-density polyethylene is 90% by weight or more.