JP2899147B2 - Manufacturing method of photographic support - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a resin-coated paper type photographic support in which a paper substrate (hereinafter referred to as "base paper") is coated with a resin composition containing a polyethylene resin as a main component. More specifically, the present invention relates to a method for producing a resin-coated paper-type photographic support capable of high-speed production, having a backcoat layer having good performance on the surface of the resin layer opposite to the side on which the photographic layer is provided.

[0002]

2. Description of the Related Art As a photographic support, a resin-coated paper type photographic support in which at least one surface of a substrate is coated with a resin capable of forming a film is well known. For example, Japanese Patent Publication No. 55-12584 discloses a technique for a photographic support in which a base paper is coated with a resin capable of forming a film, preferably a polyolefin resin. U.S. Patent 3,501,2
No. 98 discloses a technique for a photographic support in which both sides of a base paper are coated with a polyolefin resin. Also,
Since the rapid photographic development of silver halide photosensitive materials was applied, photographic supports in which both sides of the base paper were coated with polyethylene resin have been mainly put to practical use for photographic printing paper. Accordingly, one of the resin layers on the image forming side usually contains a titanium dioxide pigment in order to impart sharpness.

A resin-coated paper-type photographic support having a back coat layer containing a colloidal inorganic antistatic agent on the surface of the resin layer opposite to the side on which the photographic layer is provided is also known.
For example, JP-B-45-30298 and JP-B-58-56859 describe a resin-coated paper type photographic support having a back coat layer containing colloidal silica. 52-180
No. 20 or JP-B-57-9059 discloses a technique for a resin-coated paper type photographic support having a back coat layer containing colloidal alumina or synthetic hectorite clay colloid, respectively.

On the other hand, a resin-coated paper-type photographic support having a resin layer composed of a resin composition containing a low-density polyethylene resin and a high-density polyethylene resin as a main component is provided on the base paper surface opposite to the side on which the photographic layer is provided. Are known. For example,
44-22904 has a density of 0.915 g / cm ^{3 to} 0.926.
g / cm ³ , a specific low-density polyethylene resin having a melting index of 2.9 g / 10 min to 16 g / 10 min and a density of 0.960 g / cm ^{3 to} 0.975. g / cm ³ , comprising 85% to 35% by weight of a specific high-density polyethylene resin having a melting index of 5 g / 10 min to 18 g / 10 min.
There is a disclosure of a photographic support coated with a base paper with a polyethylene composition having high speed coating capability and good neck-in and pinhole. JP-B-48-9963 discloses a photographic support having good curl physical properties, in which a base paper is coated with a resin composition comprising low-density polyethylene resin: high-density polyethylene resin = 1: 1. There is. Further, Japanese Patent Application Laid-Open No. 58-95732 discloses that the density is 0.945 g / cm ³ or more and the melt index is 15 to 40 g / 10 min. 0.930 g / cm ³ or less, and the base paper was coated with a polyethylene resin composition comprising 60 parts by weight to 25 parts by weight of a low density polyethylene resin having a melt index of 1 g / 10 min to 40 g / 10 min. There is disclosure of a photographic support having good cutting properties and curl physical properties.

However, even when the resin composition comprising the low-density polyethylene resin and the high-density polyethylene resin disclosed in these prior arts is used, a resin-coated paper-type photographic support using paper as a substrate is produced at high speed. Turned out to be a serious problem. That is, when producing a resin-coated paper-type photographic support by a melt-extrusion coating method of coating the molten resin composition on a running base paper, the running speed of the base paper is 100 m / min or more; Especially 140m
If the photographic support is produced under high-speed conditions of not less than 1 / min, the adhesion between the base paper of the produced resin-coated paper-type photographic support and the polyethylene resin composition layer deteriorates, Alternatively, the resin layer tends to peel off during handling of the photographic material having the photographic support, which poses a practical problem.

The inventors of the present invention have conducted various studies and found that low density polyethylene resin having a density of 0.935 g / cm ³ or less and a melt index of 0.2 g / 10 min to 4 g / 10 min or a medium density 95 parts by weight to 75 parts by weight of a high-density polyethylene resin having a polyethylene resin of 5 parts by weight to 25 parts by weight, a density of 0.950 g / cm ³ or more, and a melt index of 18.5 g / 10 min to 50 g / 10 min. Adhesion between the base paper and the resin composition produced when a resin-coated paper-type photographic support using paper as a substrate is produced at a high speed by using a resin composition containing a polyethylene resin as a main component consisting of It has been found that the drop can be greatly improved. However, photographic supports coated with a base paper with the resin composition also have a completely different problem. That is, a backcoat layer containing a colloidal inorganic antistatic agent is applied to the surface of the resin composition layer of the photographic support to produce an antistatic photographic support having a backcoat layer. In this case, the adhesion between the resin composition layer and the back coat layer in the dry state and the wet state is significantly reduced, and the handling of the photographic support and the handling of the photographic material having the photographic support are remarkably reduced. In the meantime, it was found that the back coat layer dropped off or the film was poorly formed, which caused an extremely large problem in practical use.

[0007]

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide good adhesion between a resin layer on the side opposite to the side on which a photographic layer is provided and a base paper, and to provide the resin layer with the performance and the resin. An object of the present invention is to provide a method for producing a resin-coated paper-type photographic support using paper as a substrate, which has an antistatic back coat layer having good adhesion to a layer and can be produced at high speed. Other objects of the present invention will become apparent from the following description.

[0008]

In order to solve the above-mentioned problems, the inventors of the present invention have made intensive studies and as a result, have found that a polyethylene resin is coated on the surface of the paper substrate opposite to the side on which the photographic layer is provided. In the method for producing a photographic support having a resin layer as a main component and having a back coat layer on the surface of the resin layer, the polyethylene resin has a density of 0.935 g / cm ³ or less and JIS K6760. 5 to 2 parts by weight of a low-density polyethylene resin or a medium-density polyethylene resin having a melt index of 0.2 g / 10 min to 4 g / 10 min.
5 parts by weight and a density of 0.950 g / cm ³ or more according to JIS
The melt index defined by K6760 is 18.
High density polyethylene resin 9 weighing 5 g / 10 min to 50 g / 10 min 9
Using a compound resin prepared by previously melting and mixing 5 parts by weight to 75 parts by weight, a resin composition containing the compound resin as a main component is melt-extruded and coated on a running paper substrate. The object of the present invention is achieved by performing an activation treatment on the surface of the coated resin layer before winding up the resin-coated paper and applying a back coat coating liquid containing a colloidal inorganic antistatic agent. Turned out to be. It has also been found that the activation treatment is a corona discharge treatment, and the object of the present invention is remarkably achieved by a corona discharge treatment in which the surface potential after the corona discharge treatment becomes positive. Further, the traveling speed of the paper substrate is 100 m / min or more,
In particular, it was found that the effect of the present invention was more remarkably exhibited at a speed of 140 m / min or more.

[0009] The low-density polyethylene resin or the medium-density polyethylene resin used in the practice of the present invention has a density of 0.935 g / cm ³ or less.
6760 melt index (hereinafter simply referred to as
MI) in the range of 0.2 g / 10 min to 4 g / 10 min, various density, MI, molecular weight and molecular weight distribution can be used alone or in combination. Oh
Tokure - Bed low-density polyethylene resins, tubular over low-density polyethylene resins, linear low-density polyethylene resins, medium-density polyethylene resins, ethylene and propylene,
Various materials such as a copolymer with an α-olefin such as butylene, a carboxy-modified polyethylene resin, and a mixture thereof can be used.

The high-density polyethylene resin used in the practice of the present invention has a density of 0.950 g / cm ³ or more and an MI of 18.5 g / 10 min to 50 g / 10 min. If so, various densities, MI, molecular weight, those of molecular weight distribution can be used alone or in combination, and also, a normal high density polyethylene resin, ethylene and propylene,
Various types such as copolymers with α-olefins such as butylene and mixtures thereof can be used.

The proportion, density, and MI of the low-density polyethylene resin, the medium-density polyethylene resin, and the high-density polyethylene resin used in the practice of the present invention are determined based on the resin mixability, processability, and processability when producing a photographic support. Adhesiveness between the base paper of the photographic support and the resin composition layer, curl properties,
The adhesiveness to the back coat layer and the like were determined from comprehensive observations as a result of trial and error experiments and arrived at the present invention. In particular, the amount of the high-density polyethylene resin used in the resin composition comprising the high-density polyethylene resin and the low-density or medium-density polyethylene resin is 95 parts by weight to 75 parts by weight. Adhesion between the paper and the resin layer, the physical properties of the curl, etc. deteriorate, which is a problem.
This is a problem because the adhesion between the base paper and the resin layer and the adhesion between the resin layer and the back coat layer are deteriorated.
It is in the range of parts by weight to 77 parts by weight. The MI of the high-density polyethylene resin is 18.5 g / 10 min to 50 g / 10 min.
However, if it is lower than 18.5 g / 10 min, the adhesion between the base paper and the resin layer and the high-speed processability are deteriorated, and if it is higher than 50 g / 10 min, the mixing property of the resin becomes poor. However, the processability, the adhesion between the resin layer and the back coat layer, and the like are deteriorated, which is a problem, and is preferably in the range of 18.5 g / 10 min to 45 g / 10 min, particularly preferably 20 g / 10 min to 36 g / min. The range is 10 minutes. The density of the high-density polyethylene resin is 0.95
Although it is 0 g / cm ³ or more, if the density is lower than 0.950 g / cm ³ , the physical properties of the curl deteriorate, which is a problem, and preferably 0.955 g / cm ³ or more.

On the other hand, the MI of the low-density polyethylene resin or the medium-density polyethylene resin used in the practice of the present invention is in the range of 0.2 g / 10 min to 4 g / 10 min.
If it is less than g / 10 minutes, the mixing properties of the resin, the adhesion between the base paper and the resin layer, and the high-speed processability will deteriorate, and if it is higher than 4 g / 10 minutes, the high-speed processability will deteriorate. -Physical properties also tend to be poor, which is a problem, preferably from 0.3 g / 10 min to 3 g /
10 minutes, particularly preferably 0.3 g / 10 minutes to 1.5 g / 10
Range of minutes. The density of the low-density polyethylene resin or the medium-density polyethylene resin is 0.935 g.
/ cm ³ or less, and when the density is higher than 0.935 g / cm ³ , the processability of the resin composition, the adhesion between the base paper and the resin layer and the like are deteriorated, which is a problem, preferably 0.930 g. / cm ³ or less.

The polyethylene resin used in the practice of the present invention is used as a compound resin prepared by melting and mixing in advance. Various methods can be used to prepare a compound resin by previously melting and mixing a low-density polyethylene resin or a medium-density polyethylene resin and a high-density polyethylene resin. For example, using a kneading extruder, a heating roll kneader, a Banbury mixer, a pressure kneader, or the like, a predetermined amount of a low density or medium density polyethylene resin and a high density polyethylene resin, and if necessary, After the addition and melting and mixing of various additives such as a lubricant, a method of pelletizing the mixture is advantageously used. When polyethylene-based resin is not used as the compound resin, but is directly added to the melt extruder in the state of simple mixing and melt-extruded and coated, the adhesiveness between the base paper and the resin layer, the back coat coating liquid However, the applicability, the adhesiveness between the resin layer and the back coat layer, the mixing property of the resin, the workability, etc. are deteriorated, which is a problem.

The photographic support according to the present invention is a so-called melt extrusion coating in which a polyethylene resin composition is cast on a running base paper from a slit die into a film by using a melt extruder. It is manufactured by the method. At that time, the temperature of the molten film is preferably 280 to 340 ° C. As the slit die, a flat die such as a T-type die, an L-type die and a fishtail type die is preferable, and the slit opening diameter is 0.1 mm to 2 mm.
mm is desirable. Before coating the resin composition on the base paper, the base paper is preferably subjected to an activation treatment such as a corona discharge treatment or a flame treatment. Also, Tokiko Sho 61
As described in JP-A-42254, it is preferable to coat a resin layer on the running base paper after spraying an ozone-containing gas on the molten resin composition on the side in contact with the base paper. The thickness of the resin layer on the side opposite to the side on which the photographic layer is provided (hereinafter simply referred to as the back side) is not particularly limited, but is generally 5 μm 4 to 50 μm.
It is preferable that the back surface is processed to a matte surface by a rough roll.

The surface of the photographic support according to the present invention on the side on which the photographic layer is provided (hereinafter simply referred to as the surface) is usually coated with a resin capable of forming a film. As the resin capable of forming a film, thermoplastic resins such as polyolefin resin, polycarbonate resin, polyester resin, and polyamide resin are preferable.
Polyolefin resins are more preferred from the viewpoint of sticking properties. Further, it may be coated with an electron beam curable resin described or exemplified in JP-B-60-17104. Polyolefin resins preferably used include homopolymers such as polyethylene, polypropylene, polybutene and polypentene, and copolymers composed of two or more α-olefins such as ethylene-butylene copolymers, and mixtures thereof. Polyethylene resins are particularly preferred from the viewpoint of extrusion coating properties and adhesion to the base paper. Examples of such polyethylene resins include low-density polyethylene, medium-density polyethylene, high-density polyethylene, linear low-density polyethylene, ethylene and propylene, copolymers of α-olefins such as butylene, carboxy-modified polyethylene, and the like. A mixture having various densities, MI, molecular weight, and molecular weight distribution can be used.
90 g / cm ^{3 to} 0.97 g / cm ³ , MI 1 g / 10 min to 3
Those having a molecular weight of 0 g / 10 min and a molecular weight of 20,000 to 250,000 can be advantageously used alone or in combination.

The resin layer of the photographic support according to the present invention may contain various additives. Tokiko
No. 60-3430, JP-B-63-11655, JP-B-1-38291, JP-B1-38292, JP-A-1-105245 and the like or titanium oxide, zinc oxide, talc, calcium carbonate, etc. White pigments, fatty acid amides such as stearic acid amide, arachidic acid amide, etc .; fatty acid metal salts such as zinc stearate, calcium stearate, aluminum stearate, magnesium stearate, zinc palmitate, zinc myristate, calcium palmitate; -1052
No. 45 or various antioxidants such as hindered phenol, hindered amine, phosphorus-based, and sulfur-based pigments, and bull-based pigments and dyes such as cobalt blue, ultramarine, celian blue, and phthalocyanine blue. , cobalt violet, containing in combination fast violet, magenta pigments and dyes such as manganese violet, a fluorescent whitening agent according or exemplified in Japanese Patent Laid-Open 2-2544 4 No. 0, various additives such as ultraviolet absorber suitably I can do it. Preferably, these additives are included as a masterbatch or compound of the resin. Further, the surface of the photographic support according to the present invention on the photosensitive layer side is a glossy surface.
It can be processed to a finely rough surface, matte surface or silk surface described in No. 32. Also, as the thickness of the resin layer on the front side,
Although there is no particular limitation, a thickness of about 10 μm to 50 μm is generally advantageous.

The photographic support according to the present invention is characterized in that, after the base paper is coated with the resin layer on the back side, the surface of the coated resin layer is subjected to an activation treatment until the resin-coated paper is wound up, and the colloidal inorganic charge It is manufactured by a so-called on-machine coating method in which a back coat coating liquid containing an inhibitor is applied. On the other hand, it has been found that the so-called off-machine coating method, in which a back coat coating liquid is applied after winding the resin-coated paper, has a problem in that the adhesiveness between the resin layer and the back coat layer deteriorates. Further, as the colloidal inorganic antistatic agent used in the practice of the present invention, colloidal silica, colloidal alumina, hectorite clay colloid, and a mixture thereof are preferable.

The colloidal silica preferably used in the practice of the present invention is a colloidal solution obtained by dispersing silicic anhydride (Si ₂ O ₃ ) in water with ultrafine particles mainly using water as a dispersion medium. The dispersion medium is generally water, but methanol or the like may be used in some cases. In addition, an alkali component such as Na ₂ O is used in the colloid solution for the purpose of a colloid stabilizer or the like.
And NH ₃ , formamide, ethylamine, morpholine and the like in some cases. The preferably used colloidal silica preferably has an average particle size of 5 μm to 100 μm. If the particle size of the colloidal silica is too small, the backcoat coating solution tends to gel, while if it is too large, the antistatic performance becomes insufficient. Specific examples of the colloidal silica include SNO-TEX-C, SNO-TEX-0, SNO-TEX-20, SNO-TEX-30, and SNO-TEX-S manufactured by Nissan Chemical Industries, Ltd.
There are Snowtex series such as S, Snowtex-AK.

The colloidal alumina preferably used in the practice of the present invention is a colloidal solution in which fibrous alumina hydrate is dispersed in water with fine particles mainly using water as a dispersion medium. In addition, the colloid solution often contains an acid component such as acetic acid and hydrochloric acid for the purpose of a colloid stabilizer or the like. Further, preferably used colloidal alumina,
Its size is 5 μm to 200 μm, more preferably 10 μm
mμ to 100 μm. Specific examples of the colloidal alumina include alumina sol-2 manufactured by Nissan Chemical Industries, Ltd.
And alumina sol series such as Alumina sol-300.

The hectorite clay colloid preferably used in the practice of the present invention is a colloid solution in which hectorite clay is dispersed in water with fine particles. Hectorite clay is an ideal formula W _1/3 (Mg _{8 /)} containing small amounts of alkali or alkaline earth metals, such as lithium, sodium, potassium, calcium, etc., together with related impurities such as titanium, zinc, silica, etc. ₃ Li _1/3 ) Si ₄ O _1O
Complex hydrated lithium magnesium silicate represented by (OH, F) ₂ (where W represents an interlayer ion such as lithium, sodium, potassium, calcium, and the like, and a hydroxyl ion can be replaced by a fluorine atom) It is. Specific examples of hectorite clay include Laponite S and Laponite B of Laport Industrial Co., Ltd. (UK). These hectorite clays can be obtained in the form of fine powder. In the practice of the present invention, a hectorite clay colloid solution prepared by dispersing hectorite clay in water with fine particles is prepared and used. As a method for preparing a colloid solution of hectorite clay, a method of adding hectorite clay little by little while dispersing a predetermined amount of water with a stirrer, for example, a high-speed stirrer, a homogenizer or the like, and dispersing it is preferable. When preparing a colloid solution, polyphosphates such as sodium pyrophosphate and sodium hexametaphosphate,
A dispersant such as a polyhydric alcohol such as trimethylolethane or trimethylolpropane, or a nonionic polymer such as polyethylene glycol alkyl ester can be appropriately added.

In order to incorporate the colloidal inorganic antistatic agent used in the practice of the present invention into a back coat coating,
A coating solution can be prepared and added by adding a colloid solution of an inorganic antistatic agent to the backcoat layer coating solution component or by adding a backcoat layer coating solution component to the colloid solution. The content of the colloidal inorganic antistatic agent is in the range of 5 mg / m ^{2 to} 1000 mg / m ² in solid content, preferably in the range of 15 mg / m ^{2 to} 500 mg / m ² . Is good.

Various kinds of polymers, additives and the like can be contained in the back coat coating liquid used in the practice of the present invention. A water-soluble synthetic polymer compound having a carboxyl group or a sulfone group or a salt thereof or a hydrophilic synthetic polymer colloid substance or a salt thereof described or exemplified in JP-A-59-214849 or described in JP-A-59-214849 or Exemplary polymer latex, JP-A-58-14131
Starch described or exemplified in JP-A-58-45248, polyvinylpyrrolidone described or exemplified in JP-A-58-45248, JP-A-62-22095
Polyvinyl alcohol described or exemplified in No. 0, a polymer such as chitosan described or exemplified in JP-A-63-189859, a curing agent described or exemplified in JP-B-58-56859, JP-A-59-21849 The matting agents, surfactants and the like described or exemplified in the above items can be incorporated in appropriate combinations.

In practicing the present invention, the back surface of the photographic support is subjected to an activation treatment prior to the application of the back coat coating solution. Examples of such activation treatment include corona discharge treatment, glow discharge treatment, other electron impact treatment, flame treatment, surface roughening treatment, ultraviolet irradiation treatment, and activation treatment such as ozone oxidation treatment. Corona discharge treatment is particularly preferred from the viewpoint of adhesion between the back surface of the photographic support and the back coat layer. The corona discharge treatment can be performed by the method described or exemplified in JP-B-47-51905, JP-B-48-5043 and the like. As a result of the study by the present inventors, it has been found that the object of the present invention is remarkably achieved by corona discharge treatment such that the surface potential of the back resin surface of the photographic support after corona discharge treatment becomes positive charge. did. The surface potential of the back resin surface of the photographic support after corona discharge treatment was determined by the method disclosed in
The surface potential is measured by a surface potential measuring device described or exemplified in 1-314977, and the surface potential referred to in this specification is the average surface potential. When the surface potential is positive, the object of the present invention is remarkably achieved, but the surface potential is preferably +10 volts or more, particularly preferably +20 volts or more. Specific methods of corona discharge treatment to make the surface potential positive charge include the type of corona output machine, the type and shape of corona bar,
Corona treatment conditions such as frequency, anodic current, air gap, running speed of the photographic support, and the like can be set by experiments after thinking and error.

In the practice of the present invention, the apparatus for applying the back coat coating liquid includes an air knife coater, a roll coater, a bar coater, a blade coater, and a slide. Examples include hopper coaters, gravure coaters, flexographic gravure coaters, and combinations thereof. Further, as a drying device for the applied coating liquid, a hot air dryer such as a linear tunnel dryer, an arch dryer, an air dryer, a sign cover air float dryer, an infrared heating dryer, a microwave or the like is used. And various drying devices such as a dried dryer.

The pulp constituting the base paper used in the practice of the present invention is described in JP-A-58-37642 and JP-A-60-67940.
It is advantageous to use appropriately selected natural pulp as described or exemplified in JP-A-60-69649, JP-A-61-35442, etc. Synthetic pulp and synthetic fiber may be used. Natural pulp is chlorine, hypochlorite, chlorine bleach normal bleaching treatment and alkali extraction or alkali treatment and, if necessary, hydrogen peroxide, oxidative bleaching treatment with oxygen, etc.
And softwood pulp treated in combination with them,
Wood pulp of hardwood pulp and coniferous hardwood mixed pulp is advantageously used, and various pulp such as kraft pulp, sulfite pulp and soda pulp can be used.

The base paper used in the practice of the present invention may contain various additives during preparation of the stock slurry. Examples of the sizing agent include fatty acid metal salts and / or fatty acids, alkyl ketene dimer emulsions described or exemplified in JP-B-62-7534, epoxidized higher fatty acid amides, alkenyl or alkyl succinic anhydride emulsions, and rosin derivatives. As a paper strength enhancer, anionic, cationic or amphoteric polyacrylamide, polyvinyl alcohol, cationized starch, vegetable galactomannan, etc., as a wet strength agent, polyamide polyamine epichlorohydrin resin, etc., as a filler, clay,
As a fixing agent, such as kaolin, calcium carbonate, titanium oxide, etc., water-soluble aluminum salts such as aluminum chloride and bansulfate, and as a pH adjusting agent, caustic soda, sodium carbonate, etc.
Da, sulfuric acid, etc., other JP-A-63-204251, JP-A-1-26
It is advantageous to incorporate color pigments, coloring dyes, fluorescent whitening agents and the like described or exemplified in, for example, No. 6537 in an appropriate combination.

In the base paper used in the practice of the present invention, various water-soluble polymers, antistatic agents, and additives can be contained by a spray or tab size press. Examples of water-soluble polymers include antistatic agents such as starch-based polymers, polyvinyl alcohol-based polymers, gelatin-based polymers, polyacrylamide-based polymers, and cellulose-based polymers described or exemplified in JP-A 1-266537. Emulsions such as 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, and organic antistatic agents such as polystyrene sulfonate. As latex, JP-A-49-154
No. 23, JP-A-54-111331, JP-A-55-4027, JP-A-55-4027
61-230142, described in JP-A-1-180538 or the like, ethylene or α-olefins such as styrene and acrylic acid, methacrylic acid, α, β-ethylenically unsaturated carboxylic acids such as maleic anhydride at least Emulsion or latex of copolymer, ethylene,
Emulsions or latexes of vinyl acetate copolymers, petroleum resin emulsions, etc., pigments such as clay, kaolin, talc, barium sulfate, titanium oxide, etc.
As a regulator, it is advantageous to incorporate hydrochloric acid, phosphoric acid, citric acid, caustic soda and the like, and the above-mentioned additives such as coloring pigments, coloring dyes and optical brighteners in an appropriate combination.

The base paper used in the practice of the present invention includes:
Beck smoothness specified by JIS P8119 is 1
Those having a smooth surface of at least 00 seconds are preferable, and those having a smooth surface of at least 200 seconds are more preferable. As a method for producing a base paper having a Beck smoothness of 100 seconds or more, generally, hardwood pulp that is short fiber and has high smoothness is often used and beaten by a beater so as to reduce the long fiber content as much as possible. Specifically, the beating of the pulp has a fiber length of 42 mesh residue of 20 to 45% and a freeness of 2 after the beating.
It is preferable to set it to 00 to 350 CSF.
Next, regarding the stock chiller to which the internal chemicals are added, JP-A-58-37642, JP-A-61-260240, and JP-A-61-28476.
Papermaking is performed by using an appropriate papermaking method as described or exemplified in No. 2 etc. so that a uniform formation can be obtained with a commonly used paper machine such as a fourdrinier paper machine or a round net paper machine.
Further, after papermaking, the paper is subjected to a calendar treatment using a machine calendar, a super calendar, a heat calendar or the like, whereby a base paper having a Beck smoothness of 100 seconds or more can be produced. The thickness of the base paper is not particularly limited.
ones g / m ² ~250g / m ² is preferred.

The photographic support according to the present invention usually has a surface on which a photographic layer is provided, coated with a film-forming resin, preferably a polyolefin resin. In, after performing an activation treatment such as corona discharge treatment, flame treatment, JP-A-61-84643,
JP-A-1-92740, JP-A-1-102551, JP-A-1-66035
The undercoat layer described in the above item or exemplified herein can be applied.

The photographic support in the present invention is coated with various photographic constituent layers and is used for color photographic printing paper, for black-and-white photographic printing paper, for typesetting photographic paper, for copying photographic paper, for reversal photographic material, The silver salt diffusion transfer method can be used for various purposes such as negative and positive, and printing materials. For example, a silver chloride, silver bromide, silver chlorobromide, silver iodobromide, silver chloroiodobromide emulsion layer can be provided. Color coupler in silver halide photographic emulsion layer
To provide a multi-layer silver halide color photographic constituting layer. Further, a photographic component layer for a silver salt diffusion transfer method can be provided. As a binder for these photographic constituent layers, in addition to ordinary gelatin, hydrophilic polymer substances such as polyvinylpyrrolidone, polyvinyl alcohol, and sulfate compounds of polysaccharides can be used. Further, the above-mentioned photographic constituent layer can contain various additives. For example, as sensitizing dyes, cyanine dyes, merocyanine dyes, etc., as chemical sensitizers, water-soluble gold compounds, sulfur compounds, etc., as antifoggants or stabilizers, hydroxy-triazolopyrimidine compounds, mercapto-heterocyclic compounds, etc. , Hardening agents such as formalin, vinylsulfone compounds and aziridine compounds, coating aids such as alkylbenzenesulfonates and sulfosuccinate salts, etc., dialkylhydroquinone compounds etc. as antifouling agents, and other fluorescent brighteners, improving sharpness Dye, antistatic agent, pH adjuster,
A fogging agent and a water-soluble iridium compound, a water-soluble rhodium compound, and the like at the time of generation and dispersion of silver halide may be incorporated in an appropriate combination.

The photographic material according to the present invention can be used in accordance with the photographic material according to the exposure and exposure methods described in "Photosensitive Material and Handling Method" (Kyoritsu Shuppan, Goro Miyamoto, Photographic Technology Course 2).
Processing such as development, stopping, fixing, bleaching, and stabilization are performed. In particular, a multilayer silver halide color photographic light-sensitive material which is subjected to a single-bath bleach-fixing process after a color development phenomenon is CD-III or CD-IV.
(The above two compounds are trade names of Kodak Co., Ltd.) and droxychrome (trade name of May & Baker Co., Ltd.) can be treated with a color developing solution of any principal agent. The developer containing such a main agent may contain a development accelerator such as benzyl alcohol, thallium salt, and phenidone.
Processing can also be carried out with a developer substantially free of benzyl alcohol. A useful one-bath bleach-fixing solution is a solution of a metal salt of aminopolycarboxylic acid (for example, a ferric complex salt such as ethylenediaminetetraacetic acid or propylenediaminetetraacetic acid). As a fixing agent, sodium thiosulfate is used. And ammonium thiosulfate are useful. Various additives can be contained in such a one-bath bleach-fix solution. For example, a desilvering accelerator (e.g., mercaptocarboxylic acid described in U.S. Pat. No. 3,512,979, Bergi-Patent No. 682,426)
, A stain inhibitor, a pH regulator or a pH buffer, a hardener (for example,
Various compounds such as magnesium sulfate, aluminum sulfate, potassium alum and the like can be contained in combination. Further, such a single-bath bleach-fixing solution can be used at various pHs, but a useful pH range is pH6.
0 to 8.0.

[0032]

EXAMPLES Next, in order to explain the present invention more specifically,
An embodiment will be described.

Example 1 A mixed pulp of a hardwood bleached sulphite pulp and a hardwood bleached kraft pulp was beaten into 320 ml of Canadian Standard Freeness. Parts by weight, 0.2 parts by weight of anionic polyacrylamide, 0.4 parts by weight of an alkyl ketene dimer emulsion (as ketene dimer), and 0.4 parts by weight of a polyamide polyamine epichlorohydrin resin, and a basis weight of 160 g / m ^2. Manufactured paper. The obtained wet paper was dried at 110 ° C., and subsequently 3 parts by weight of carboxy-modified polyvinyl alcohol, 0.05 parts by weight of fluorescent whitening agent, 0.002 parts by weight of blue dye, 4 parts by weight of sodium chloride, and 0 parts of citric acid The impregnating solution of 0.2 parts by weight and 93 parts by weight of water was impregnated with 25 g / m ² , dried with hot air at 110 ° C., and further subjected to a super calender treatment at a linear pressure of 90 kg / cm to obtain a photographic support. Base paper was manufactured. At this time, the Bekk smoothness of the base paper was 200 seconds.

Next, after the base paper surface (back surface) opposite to the side on which the photographic layer is coated is subjected to corona discharge treatment, the back surface is coated with the polyethylene resin composition shown in Table 1 at a resin temperature of 325 ° C. for 2 hours.
It was melt-extruded and coated to a thickness of 5 μm at a running speed of the base paper of 140 m / min.

Subsequently, after the surface of the base paper was subjected to corona discharge treatment, a low-density polyethylene resin (density 0.92
0 g / cm ³ , MI = 8.5 g / 10 min) 47.5 wt%, anatase surface-treated with hydrous aluminum hydroxide (0.75 wt% as Al ₂ O ₃ min with respect to titanium dioxide) 20 parts by weight of a master batch of titanium dioxide pigment composed of 50% by weight of titanium dioxide pigment and 2.5% by weight of zinc stearate, a low density polyethylene resin (density 0.920 g / c
m ³ , MI = 4.5 g / 10 min) 65 parts by weight and high density polyethylene resin (density 0.970 g / cm ³ , MI = 7.0 g / 10)
Min) a resin composition consisting of 15 parts by weight at a resin temperature of 325 ° C.
At a running speed of 140 m / min of the base paper. In addition, the melt extrusion coating of the front and back polyethylene resins was performed by a so-called tandem method in which extrusion coating was performed sequentially.
At that time, the surface of the resin layer containing the titanium dioxide pigment of the resin-coated paper was processed into a finely rough surface, and the surface quality of the resin layer on the back was processed into a matte surface such as paper.

Further, after the corona discharge treatment under the conditions shown in Table 1 on the back resin layer surface of the resin-coated paper, the following backcoat coating solution was applied on-machine or off-machine under the application conditions shown in Table 1. As dry weight, colloidal silica:
Styrene latex = 1: 1, and a backcoat coating solution containing 0.021 g / m ² of sodium polystyrene sulfonate and an appropriate amount of a coating aid in addition to 0.21 g / latex (calculated as solid weight) The photographic support was obtained by coating with a coating amount of m ² . For comparison, a photographic support coated with a back coat coating solution containing no colloidal silica in the combinations shown in Table 1 was obtained.

Each of the samples obtained as described above was
After storing for 1 day in a thermo-hygrostat at 60 ° C. and 60% RH, the evaluation was performed by the method described below.

As a method for evaluating the workability of the polyethylene resin composition at the time of producing the photographic support, the length of the resin-coated portion on the back side in the lateral direction is measured to evaluate the degree of neck-in, and to evaluate the degree of neck-in per 10 m ² . The uniformity of the film such as the degree of generation of streaks and the degree of generation of resin gel in the area was evaluated, and the processability of the polyethylene resin composition was comprehensively evaluated. The evaluation criteria are as follows: ：: good, Δ: slightly bad but no practical problem, x: bad and practically problematic.

As a method for evaluating the adhesiveness between the base paper of the photographic support and the backside resin layer, the base paper layer of the sample was peeled off from the backside polyethylene layer, and the base paper layer adhered to the peeled polyethylene layer was peeled off. The adhesiveness between the base paper and the backside resin layer was evaluated by measuring the area ratio. The evaluation criteria are as follows: ：: good when the area ratio is 100%, Δ: 80 when the area ratio is less than 100%
% Or more, and the adhesiveness is slightly poor but there is no practical problem. X: The area ratio is less than 80%, and the adhesiveness is poor and there is some practical problem.

In order to evaluate the adhesion between the back coat layer of the photographic support and the backside resin, the back coat surface of the sample was brought into contact with a cotton fabric and moved at a constant speed under a constant load. Evaluation was made based on the degree of abrasion of the back coat at the time.
The evaluation criteria were as follows: ：: good with little scratches, Δ:
Scratches are somewhat large and adhesiveness is slightly poor, but there is no practical problem. X: Scratches are large and poor adhesiveness, indicating some practical problems.

The antistatic performance of the back coat layer of the photographic support was evaluated by measuring the surface resistivity of the sample before and after color development at 20 ° C. and 40% RH. . The evaluation criteria are as follows: ：: good, Δ: slightly insufficient but not practically problematic, x: poor in antistatic performance, showing some practical problems.

The curl physical properties of the photographic support were evaluated as follows. First, a corona discharge-treated blue-sensitive emulsion layer containing a yellow color coupler, an intermediate layer containing a color-mixing inhibitor, and a green color layer containing a magenta color coupler on the front side resin surface containing a titanium dioxide pigment of a photographic support. Emulsion layer,
UV absorbing layer containing UV absorber, cyan color coupler
A color photographic paper having a total amount of gelatin of 8 g / m ² was prepared by providing a red-sensitive emulsion layer and a protective layer. Each color-sensitive emulsion layer comprises a silver chlorobromide which corresponds to 0.6 g / m ² with silver nitrate, further formation of the silver halide, other gelatin required dispersion and film formation, an appropriate amount of antifoggants, the sensitizing dye , A coating aid, a hardener, a thickener, and an appropriate amount of a filter dye. next,
7. The prepared color photographic paper was stored at 35 ° C. and normal humidity for 5 days, and then at 20 ° C. and 40% RH after color color development.
The state of the color of the color print of 2 cm × 11.7 cm was evaluated. The evaluation criteria were as follows: ○: slightly negative (curl toward the back coat layer) and extremely flat, good curl physical properties, Δ: slightly positive (curl to the photographic constituent layer) But there is no practical problem,
×: Positive color is large, indicating that there is some practical problem.

The results obtained are shown in Table 1.

[0044]

[Table 1]

Note that (Note 1) to (Note 6) in Table 1 are as follows.

(Note 1) ○ indicates the sample No. according to the present invention. Represents

(Note 2) HDPE: density 0.960 g / c
m ³ , MI = 20 g / 10 min high density polyethylene resin.

(Note 3) LDPE: density 0.918 g / c
m ³ , MI = 1.3 g / 10 min low density polyethylene resin.

(Note 4) Preparation method of polyethylene resin composition-compound: HDPE and LDPE are used as compound resin pellets prepared by melting and mixing in advance using a kneading extruder. Simple mixing: HDPE
And LDPE are added to a melt extruder with simple mixing and used.

(Note 5) Application condition of back coat liquid to on-machine coating: After coating the resin layer on both sides of the base paper with a melt extruder, the back side of the resin coated paper is wound up before winding. After applying a corona discharge treatment to the resin surface so that the average surface potential becomes 50 volts, a back coat coating solution is applied on-machine. Off-machine coating: The resin-coated paper is wound once, stored for one day, subjected to corona discharge treatment on the resin surface on the back side so that the average surface potential becomes 50 volts, and then coated with a back coat coating liquid.

(Note 6) Type of backcoat coating solution-A: Backcoat coating solution containing colloidal silica in the coating solution, B:
A comparative backcoat coating liquid having no colloidal silica in the coating liquid.

From the results shown in Table 1, it can be seen that a resin composed of a compound resin prepared by previously melting and mixing 5 to 25 parts by weight of a low density polyethylene resin and 95 to 75 parts by weight of a high density polyethylene resin in the present invention. After the composition is melt-extruded and coated, the back side of the resin layer is subjected to a corona discharge treatment until the resin-coated paper is wound up, and a back coat containing colloidal silica as a colloidal inorganic antistatic agent. The photographic support according to the present invention (samples No. 2 to No. 4 and No. 9) coated with a coating solution was prepared by processing the polyethylene resin composition, the adhesiveness between the base paper and the resin layer, It can be clearly seen that this is an excellent photographic support in which the adhesiveness between the coating layer and the resin, the antistatic performance of the back coat layer and the curl physical properties are good.

On the other hand, it can be seen that the samples outside the present invention each have problems. When the content of the high-density polyethylene resin is more than 95 parts by weight (Sample No. 1), the processability of the polyethylene resin composition and the adhesion between the back coat layer and the resin are poor, which is problematic. When the content of the high density polyethylene resin is less than 75 parts by weight (Sample No. 1)
In the case of 0), the physical properties of the curl are poor, which is a problem. In addition, as a method of preparing the polyethylene resin composition, in the case of simple mixing (Sample No. 5), the processability of the polyethylene resin composition is poor, which is a problem. -Adhesion between the resin layer and the resin tends to be poor. Further, in the case of off-machine coating (Sample No. 6), the adhesion between the back coat layer and the resin is poor, which is a problem, and the back coat layer containing no colloidal inorganic antistatic agent is problematic. When coated (Sample Nos. 7 to 8), there is a problem because the antistatic performance of the back coat layer is poor.

Example 2 Sample No. 1 of Example 1 Sample No. 4 of Example 1 except that the resin shown in Table 2 was used instead of the polyethylene resin for back surface coating used in Example 4. Performed in the same manner as 4.

Table 2 shows the obtained results.

[0056]

[Table 2]

Note that (Note 7) to (Note 8) in Table 2 are as follows.

(Note 7) ○ indicates a sample according to the present invention.

(Note 8) Resin composition-density 0.960 ±
0.002 g / cm ³ high density polyethylene resin (HDPE) 8
A resin composition comprising 0 parts by weight and 20 parts by weight of a low density polyethylene resin (LDPE) having a density of 0.920 ± 0.002 g / cm ³ .

From the results shown in Table 2, the MI of the high-density polyethylene resin used in the practice of the present invention was 18.5 g /
A range of 10 minutes to 50 g / 10 minutes is effective, preferably 1
8.5 g / 10 min to 45 g / 10 min, particularly preferably 20 g / 10 min
It is well understood that the range is from g / 10 minutes to 36 g / 10 minutes. Further, the MI of the low-density polyethylene resin used in the practice of the present invention is effective in the range of 0.2 g / 10 min to 4 g / 10 min, preferably 0.3 g / 10 min to 3 g / 10 min. It can be seen that the range is particularly preferably 0.3 g / 10 min to 1.5 g / 10 min.

Example 3 Sample No. of Example 1 Sample No. 1 of Example 1 was repeated except that the polyethylene resin composition for coating the back surface used in Example 4 was replaced with the one shown in Table 3. Performed in the same manner as 4.

Table 3 shows the obtained results.

[0063]

[Table 3]

Note that (Note 9) to (Note 10) in Table 3 are as follows.

(Note 9) ○ indicates a sample according to the present invention.

(Note 10) Resin composition to MI 21 ± 1 g / 10
80 parts by weight of high density polyethylene resin (HDPE) and MI
1.3 ± 0.2g / 10min low density polyethylene resin (LDP
E) 20 parts by weight of a resin composition.

From the results shown in Table 3, the high-density polyethylene resin used in the practice of the present invention has a density of 0.950.
g / cm ³ or more is effective, preferably 0.955
It can be clearly seen that it is g / cm ³ or more. As the low-density polyethylene resin used in the practice of the present invention, those having a density of 0.935 g / cm ³ or less are effective, and it is well understood that the resin is preferably 0.930 g / cm ³ or less.

Example 4 Sample No. 1 of Example 1 Sample No. 4 of Example 1 except that the resin surface on the back side before applying the back coat coating liquid was subjected to corona discharge treatment so that the average surface potential became the value shown in Table 4. Performed in the same manner as 4.

Table 4 shows the obtained results.

[0070]

[Table 4]

From the results in Table 4, it can be seen that the corona discharge treatment on the backside resin surface before the application of the backcoating coating solution is such that the average surface potential is positive in view of the adhesiveness between the backcoat layer and the resin. It is clear that the treatment is preferably performed so that the average surface potential becomes +10 volts or more, and it is more preferable to perform the treatment so that the average surface potential becomes +20 volts or more.

Example 5 Instead of the colloidal silica used in Example 1 as a colloidal inorganic antistatic agent, a synthetic hectorite clay colloid or alumina sol was used in an amount of 1/2 or 3 of the colloidal silica, respectively (solids calculation). ) Was carried out in the same manner as in Example 1 except for using, and the same results as in Example 1 were obtained.

[0073]

According to the present invention, a back coat having good adhesion between a resin layer on the side opposite to a side on which a photographic layer is provided and a base paper, and excellent adhesion to the resin layer and antistatic performance. The present invention can provide an excellent resin-coated paper-type photographic support having a protective layer on the surface of the resin layer, good curl properties, and good workability.

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int.Cl. ⁶ , DB name) G03C 1/79 G03C 1/85

Claims (3)

(57) [Claims] 1. A photographic apparatus having a resin layer composed of a resin composition containing a polyethylene resin as a main component on a surface of a paper substrate opposite to a side on which a photographic layer is provided, and having a back coat layer on the surface of the resin layer. In the method for producing a support, the polyethylene resin has a density of 0.935 g / cm ³ or less, and
The melt index defined by K6760 is 0.2
g / 10 minutes to 4 g / 10 minutes, 5 to 25 parts by weight of a low-density polyethylene resin or a medium-density polyethylene resin having a density of 0.950 g / cm ³ or more, and a melt index specified by JIS K6760. 18.5g / 10min ~ 50g /
Using a compound resin prepared by previously melting and mixing 95 parts by weight to 75 parts by weight of a high-density polyethylene resin for 10 minutes, melting a resin composition containing the compound resin as a main component on a running paper substrate After the extrusion coating, before the resin-coated paper is wound up, the surface of the coating resin layer is subjected to an activation treatment, and a backcoat coating liquid containing a colloidal inorganic antistatic agent is applied. A method for producing a photographic support. 2. The method according to claim 1, wherein the activation treatment is a corona discharge treatment, and the surface potential of the coated resin surface after the corona discharge treatment is a positive charge. 3. The method for producing a photographic support according to claim 1, wherein the traveling speed of the paper substrate is 100 m / min or more.