JPH10112025A - Magnetic recording medium and its production - Google Patents

Abstract

PROBLEM TO BE SOLVED: To decrease clogging of a magnetic head after wet developing treatment, to prevent contamination of a head and to improve scratching resistance and durability of a coating film by adding and mixing wafer into a coating liquid for a magnetic recording so as to give head cleaning property to the recording medium. SOLUTION: Water is not directly added to a coating liquid for magnetic recording to produce a magnetic recording layer, but water is preliminarily added and uniformly mixed into an org. solvent which constitutes the coating liquid for the magnetic recording layer and then the mixture solvent is added to the coating liquid for the magnetic recording layer. In this case, as for the magnetic fine powder used for the magnetic recording layer, a metal magnetic powder, iron oxide magnetic powder, Co-doped iron oxide magnetic powder, chromium dioxide magnetic powder, barium ferrite magnetic powder, etc., can be used.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic recording medium, and more particularly, to a magnetic recording medium having improved prevention of clogging of a magnetic head and improved scratch resistance and durability of a coating film, and a method of manufacturing the same.

[0002]

2. Description of the Related Art Generally, a magnetic recording medium reads and writes information with a magnetic head. In order to quickly and accurately input and output information, the magnetic recording medium and the magnetic head must always be in an optimal environment. . However, due to the contact between the surface of the magnetic recording medium, in which the magnetic particles mainly composed of iron oxide are dispersed in the synthetic polymer binder, and the magnetic head, which is a metal, dust, dust, In some cases, dust or components of the magnetic recording medium adhere and cause clogging, which may hinder information input / output.

[0003] These problems are almost completely eliminated by cleaning the magnetic head.
Even if it is effective against dust, dust, and dust, it is not perfect against the adhesion of components of the magnetic recording medium. Further, the preparation of the cleaning member and the trouble of the cleaning still exist.

In recent years, silver halide color photographic materials (hereinafter simply referred to as photographic materials) have been used for photographing (image exposure).
In order to more efficiently and later perform development processing and printing on photographic paper with high accuracy, there is a proposal to record information on photographing conditions and the like on a color photosensitive material for effective use.

US Pat. No. 4,947,196 and WO 90/04254 disclose a roll-shaped film and a magnetic head having a magnetic layer containing magnetic particles capable of magnetic recording on the back surface of a photographic film. An imaging camera having the same is disclosed. According to the above-described improved technology, the identification information of the type and maker of the photosensitive material, information on the conditions at the time of photographing, information on the customer, information on the printing conditions, information on the conditions for additional printing, etc. are recorded on the magnetic layer on the film. By magnetically inputting / outputting the data, it is possible to improve the print quality, increase the efficiency of the printing operation, increase the efficiency of the lab work, and the like.

In other words, a magnetic recording medium is provided on one side of the support, and a photographic component layer is provided on the other side, which can be said to be an epoch-making recording medium having both magnetic information and optical image information.

However, there is a problem of the clogging of the magnetic head, and a new clogging factor relating to the photographic constituent layer and its developing process is added. It is difficult to cope with the conventional cleaning means alone, and there is a need for fundamental improvement of the magnetic recording medium itself.

Further, conventionally, a crosslinking agent was added to the magnetic recording layer, and the reaction between the binder and the crosslinking agent was carried out by heat treatment after the formation of the film. The heating temperature and the number of days are limited due to blocking and transfer between the magnetic recording layer surface and the surface having the magnetic recording layer surface, which is opposite to the surface having the magnetic recording layer surface, via the support.

Further, in the case of the crosslinking catalysts described in JP-A-7-219123 and JP-A-7-296368, it is difficult to control the reaction rate, and it is impossible to control the viscosity stability of the coating solution and the activity of the crosslinking agent itself. It was difficult to handle such as frequent occurrence and clogging of the coating liquid sending line, and it was difficult to put it to practical use.

JP-A-3-1318 discloses a magnetic recording medium in which the water content of a coating solution for a magnetic layer is set to 0 to 0.2% by weight and reacted with cyanoacrylate or methacryloyl isocyanate contained in the magnetic layer. There is a description that the Young's modulus can be increased and the running durability can be dramatically improved.However, this water content is controlled by the water content of the magnetic powder to be added, It is also used to shut off the moisture of nitrogen with nitrogen purge etc.
It is described in terms of how to reduce the water contained in the coating solution, and an invention that aims to improve the reactivity of the crosslinking agent by positively adding the water of the present invention to the magnetic layer coating solution. Is completely different.

Therefore, the method described in JP-A-3-1318 cannot achieve the problems described later of the present invention, and it is difficult to keep the reactive group of the crosslinking agent in the coating solution unreacted until the coating film is dried. there were.

[0012]

SUMMARY OF THE INVENTION In view of the above problems, an object of the present invention is to firstly provide head cleaning properties to reduce clogging of a magnetic head after a wet development process. . A second object is to provide a magnetic recording medium with less head contamination. A third object is to provide a magnetic recording medium having an improved scratch resistance and an improved durability of a coating film by sufficiently crosslinking a binder and a crosslinking agent in a magnetic layer.

[0013]

The above object of the present invention is achieved by the following means.

A method for producing a magnetic recording medium having a magnetic recording layer on a support, wherein water is added to and mixed with the coating solution for the magnetic recording layer.

The method for producing a magnetic recording medium according to the above item, wherein the amount of water contained in the coating solution for the magnetic recording layer is 0.3 to 20% by weight based on the weight of the coating solution.

The method of adding water to the magnetic recording layer coating solution according to the above item or the item, is that water is added to an organic solvent constituting the coating solution, mixed uniformly, and then added to form a magnetic recording coating solution. A method for producing a magnetic recording medium, which is prepared.

[0017] Any one of the above items 1 to 5, wherein 50% by weight or more of the organic solvent excluding water of the coating solution for the magnetic recording layer is an organic solvent containing a ketone group.
The method for producing a magnetic recording medium according to any one of the preceding claims.

The magnetic recording medium according to any one of the above items 1 to 3, wherein the binder in the magnetic recording layer is a cellulose ester.

The magnetic recording medium according to the above item, wherein the cellulose ester is diacetyl cellulose.

The magnetic recording medium according to the above item or the item, wherein the binder in the magnetic recording layer has a weight average molecular weight of 20,000 to 300,000.

Hereinafter, the present invention will be described in detail.

By containing water in the coating solution for the magnetic recording layer for preparing the magnetic recording medium to be subjected to the wet development processing of the present invention, simultaneous crosslinking with drying of the coating film of the magnetic recording layer, which has not been possible in the past, can be achieved. Acceleration and shortening of the heat treatment days are possible, and the coating of the magnetic recording layer is cured by simultaneous crosslinking with the drying of the coating of the magnetic recording layer. Blocking and transfer with the opposite surface can be prevented, and it is also possible to increase the temperature and humidity during the heat treatment, further increase the degree of crosslinking of the coating film and easily handle the coating liquid. It has been found. And the performance aimed at by the present invention could be achieved.

When water is directly added to a magnetic recording layer coating solution simply for producing a magnetic recording layer, the solubility of a binder contained in the magnetic recording layer coating solution is disturbed by local presence of water, It deteriorates the coating film formation or reacts with the cross-linking agent contained in the coating solution for the magnetic recording layer before coating due to the local presence of water, causing problems such as an increase in the viscosity of the coating solution and a coating failure accompanying the coating solution. At present, the original crosslinking ability of the crosslinking agent cannot be obtained.

Therefore, water is added in advance to the organic solvent constituting the coating solution for the magnetic recording layer, without adding water directly to the coating solution for the magnetic recording layer for preparing the magnetic recording layer, and uniformly mixed. After that, the object and effect of the present invention can be achieved only by adding to the coating solution for the magnetic recording layer.

The magnetic fine powder used in the magnetic recording layer of the present invention includes metal magnetic powder, iron oxide magnetic powder, C
o-doped iron oxide magnetic powder, chromium dioxide magnetic powder,
A barium ferrite magnetic powder or the like can be used.

The method for producing these magnetic powders is known.
The magnetic powder used in the present invention can also be manufactured according to a known method.

The shape and size of the magnetic powder can be widely used without any particular limitation. Needle shape, rice grain shape,
It may have any shape such as a spherical shape, a cubic shape, and a plate shape, but is preferably a needle shape or a plate shape in terms of electromagnetic conversion characteristics. There are no particular restrictions on the crystal size and specific surface area. The magnetic powder may be surface-treated.
For example, titanium, silicon, may be surface-treated with a substance containing an element such as aluminum, carboxylic acid, sulfonic acid, sulfate, phosphonic acid, phosphate,
It may be treated with an organic compound such as an adsorptive compound having a nitrogen-containing heterocycle such as benzotriazole. The pH of the magnetic powder is not particularly limited, but is preferably in the range of 5 to 10.

As the metal magnetic powder, for example, a metal content is 75% by weight or more, and a metal content is 80% by weight or more and a ferromagnetic metal or alloy (Fe, Co, Ni, Fe—C
o, Fe-Ni, Co-Ni, Co-Fe-Ni, etc.)
And 20% by weight or less of other components (Al, Si, S,
Sc, Ti, V, Cr, Mn, Cu, Zn, Y, Mo,
Rh, Pd, Ag, Sn, Sb, B, Ba, Ta, W,
Re, Au, Hg, Pb, P, La, Ce, Pr, N
d, Te, Bi, etc.). Also,
The ferromagnetic metal component may contain a small amount of hydroxide or oxide.

Examples of the iron oxide of the iron oxide magnetic material and the Co-doped iron oxide magnetic material include γ-iron oxide.
The ratio of divalent iron / trivalent iron in these iron oxides is not particularly limited.

These magnetic recording layers are disclosed in
Nos. 7-32812 and 53-109604.

Regarding the size of magnetic particles, it is known that there is a correlation between the size and the transparency.
Vol. 20, No. 2, "Characteristics of Ultrafine Particle Translucent Magnetic Recording Material and Its Application". For example, in the acicular powder of γ-Fe ₂ O ₃ , the light transmittance is improved by reducing the particle size.

US Pat. No. 2,950,971 describes that a magnetic layer composed of magnetic iron oxide dispersed in a binder transmits infrared rays. US Pat. No. 4,279,945 describes Describes that, even when the concentration of magnetic particles in the magnetic layer is relatively large, reducing the particle size improves the transmittance of helium-neon laser light having a wavelength of 632.8 nm.

However, when a magnetic recording layer is provided in an image forming area of a silver halide color photographic light-sensitive material, the light transmittance of not only a red area but also a green area and a blue area must be high.

In order to increase the light transmittance in the red, green and blue regions, the particle size of the magnetic particles is reduced and the amount of the magnetic particles applied is also limited.

If the particle diameter of the magnetic particles is reduced to a certain degree or more, required magnetic characteristics cannot be obtained. Therefore, it is preferable to reduce the particle size of the magnetic powder as long as necessary magnetic characteristics can be obtained. Also, if the coating amount of the magnetic particles is reduced to a certain level or more, the required magnetic characteristics cannot be obtained. Therefore, it is preferable to reduce the amount in a range where the required magnetic characteristics can be obtained.

In practice, the coating amount of the magnetic powder is 0.0
01 to 3 g / m ² , and more preferably 0.01 to 1
g / m ² , particularly preferably 0.2 g / m ² or less.

Examples of the binder used for the magnetic recording layer include known thermoplastic resins, radiation-curable resins, thermosetting resins, and other reactive resins conventionally used as binders for magnetic recording media. Can be used.

As the thermoplastic resin, vinyl chloride-
Vinyl acetate copolymer, vinyl chloride resin, copolymer of vinyl acetate and vinyl alcohol, vinyl chloride-vinylidene chloride copolymer, vinyl chloride-acrylonitrile copolymer,
Vinyl polymers or copolymers such as ethylene-vinyl alcohol copolymer, chlorinated polyvinyl chloride, ethylene-vinyl chloride copolymer, ethylene-vinyl acetate copolymer, nitrocellulose, cellulose acetate propionate, cellulose Cellulose derivatives such as acetate butyrate resin, maleic acid and / or acrylic acid copolymer, acrylonitrile-styrene copolymer, chlorinated polyethylene, acrylonitrile-chlorinated polyethylene-styrene copolymer, methyl methacrylate-butadiene-styrene copolymer Polymer, acrylic resin, polyvinyl acetal resin, polyvinyl butyral resin, polyester polyurethane resin, polyether polyurethane resin, polycarbonate polyurethane resin, polyester resin, polyether Fat, polyamide resins, styrene -
Rubber-based resins such as butadiene resin and butadiene-acrylonitrile resin, silicone-based resins, and fluorine-based resins can be exemplified.

The thermoplastic resin has a Tg of -40 ° C. to 1
50 ° C., preferably 60 ° C. to 120 ° C., preferably having a weight average molecular weight of 5,000 to 400,000, and more preferably having a weight average molecular weight of 10,000 to 350,000. It is.

The radiation-curable resin is a resin which is cured by radiation such as an electron beam or an ultraviolet ray, and includes a maleic anhydride type, a urethane acrylic type, an ether acrylic type, an epoxy acrylic type and the like.

Examples of the thermosetting resin and other reactive resins include a phenol resin, an amino resin, an epoxy resin, a polyurethane-based curing resin, a urea resin, an alkyd resin, and a silicone-based curing resin.

The binders listed above may have a polar group in the molecule. As the polar group, an epoxy group, -C
OOM, -OH, -N (R) 2, -N (R) 3 X, -SO
_{3 M, -OSO 3 M, -PO} 3 M 2, -OPO 3 M (M each hydrogen, an alkali metal, an ammonium, X is a counter ion to form a quaternary ammonium salt, each of R is hydrogen, an alkyl group Is represented.).

Further, a hydrophilic binder can be used as a binder of the magnetic recording layer of the present invention.

Examples of the hydrophilic binder usable in the present invention include Research Disclosure No. 1
No. 7643, p. 18716, 651
Examples include water-soluble polymers, cellulose ethers, latex polymers, and water-soluble polyesters described on the page.

Examples of the water-soluble polymer include gelatin, gelatin derivatives, casein, agar, sodium alginate, starch, polyvinyl alcohol, acrylic acid copolymers,
Maleic anhydride copolymers and the like can be mentioned, examples of cellulose ethers include carboxymethyl cellulose and hydroxyethyl cellulose, and examples of latex polymers include vinyl chloride copolymers, vinylidene chloride copolymers, and acrylic ester copolymers. Latexes such as polymers, vinyl acetate-based copolymers, butadiene-based copolymers and the like can be mentioned. The most preferred of these is gelatin.

The gelatin may be non-denatured or denatured. Further, a part thereof is colloidal albumin, casein, carboxymethylcellulose, cellulose derivatives such as hydroxyethylcellulose, agar, sodium alginate, starch derivatives, sugar derivatives such as dextran, synthetic hydrophilic colloids, for example,
Polyvinyl alcohol, poly N-vinylpyrrolidone, acrylic acid-based copolymer, polyacrylamide or a derivative thereof, a partial hydrolyzate, a gelatin derivative, or the like may be used.

It is preferable that the hydrophilic binder containing gelatin is hardened. As a hardening agent that can be used, for example,
Aldehyde compounds such as formaldehyde and glutaraldehyde, ketone compounds such as diacetyl and cyclopentanedione, bis (2-chloroethyl urea),
-Hydroxy-4,6-dichloro-1,3,5-triazine, U.S. Pat. Nos. 3,288,775 and 2,73.
No. 2,303, British Patent No. 974,723, and 1.1
No. 67,207, etc., compounds having a reactive halogen, divinyl sulfone, 5-acetyl-
1,3-Diacryloylhexahydro-1,3,5-triazine, U.S. Pat. Nos. 3,635,718 and 3,2
Compounds having a reactive olefin described in, for example, U.S. Pat. No. 32,763 and British Patent No. 994,869;
Hydroxymethylphthalimide, US Patent No. 2,73
N-methylol compounds described in U.S. Pat. Nos. 2,316 and 2,586,168;
Isocyanates described in US Pat. No. 4,017,280, US Pat. No. 3,017,280, US Pat. No. 2,983,611; US Pat. No. 2,725,294; Acid derivatives described in US Pat. No. 2,725,295, US Pat. No. 3,091,5;
Epoxy compounds described in No. 37 and the like, and halogen carboxaldehydes such as mucochloric acid can be exemplified.

Inorganic hardeners can also be used. Examples of inorganic hardeners include chromium chromium van and zirconium sulfate. JP-B-56-12853, JP-B-58-32699, Belgium Patent No. 825,726
JP-A-60-225148, JP-A-51-126
No. 125, JP-B-58-50699, JP-A-52-5
No. 4,427, U.S. Pat. No. 3,321,313 and the like.

The hardener is usually used in an amount of 0.01 to 30% by weight, preferably 0.05 to 30% by weight, based on the dry gelatin.
20% by weight.

The magnetic substance powder is dispersed in a binder using a solvent, if necessary, to form a coating solution. For dispersing the magnetic powder, a ball mill, a homomixer, a sand mill, or the like can be used. In this case, it is preferable that the magnetic particles are dispersed and dispersed as much as possible without damaging the magnetic particles.

When forming an optically transparent magnetic recording layer, the binder is used in an amount of 1 to 30 parts by weight based on 1 part by weight of the magnetic powder.
It is preferred to use parts by weight. More preferably, the amount is 2 to 20 parts by weight based on 1 part by weight of the magnetic powder. The solvent is used in such an amount that the coating can be easily performed.

The method for providing a magnetic recording layer on a support includes air doctor coating, blade coating, air knife coating, squeeze coating, impregnating coating, reverse roll coating, transfer roll coating, gravure coating, kiss coating, cast coating, and the like. Spray coats are available. In order to perform multiple stripe coating, these coating heads may be connected in multiples. As a specific method of stripe coating, for example, JP-A-48-255
No. 03, No. 48-25504, No. 48-98803
No., 50-138037, 52-15533,
Nos. 51-3208, 51-6239, 51-6
No. 5606, No. 51-140703, Japanese Patent Publication No. 29-4
No. 221, U.S. Pat. Nos. 3,062,181 and 3,2
27, 165 can be referred to.

A support having a magnetic recording layer may be prepared by co-casting a solution of a binder in which magnetic particles are dispersed and a solution of a polymer for forming a support. in this case,
The binder for dispersing the magnetic particles is preferably substantially the same as the polymer for forming the support. The support on which the magnetic recording layer is formed by co-casting may be stretched in order to satisfy mechanical strength, dimensional stability, and the like.

In order to firmly adhere these magnetic recording layers to the support, an undercoat layer may be provided on the support, and the support may be subjected to chemical treatment, mechanical treatment, corona discharge treatment, or the like.
Flame treatment, ultraviolet treatment, high frequency treatment, glow discharge treatment,
Surface activation treatment such as active plasma treatment, laser treatment, concentrated acid treatment, and ozone oxidation treatment may be performed. Furthermore, an undercoat layer may be provided after the surface activation treatment.

The thickness of the magnetic recording layer is 0.05 to 10 μm
Is preferably 0.1 to 5 μm, more preferably 0.15 to 3 μm.

The coating liquid for forming the magnetic recording layer contains a lubricant, an antistatic agent, etc. in order to give the magnetic recording layer functions such as imparting lubricity, preventing static electricity, preventing adhesion, and improving friction and abrasion characteristics. Various additives such as an agent can be added. In addition, in addition to the coating liquid, for example, a plasticizer to give flexibility to the magnetic recording layer, a dispersant to help disperse the magnetic material in the coating liquid, to prevent clogging of the magnetic head Can be added to the polishing agent. The above functions of imparting lubricity, preventing static charge, preventing adhesion, improving friction and abrasion characteristics, and preventing clogging of the magnetic head may be provided by providing these functional layers separately from the magnetic recording layer. If necessary, a protective layer adjacent to the magnetic recording layer may be provided to improve the scratch resistance. In the case where the magnetic recording layer is provided in a stripe shape, a transparent polymer layer containing no magnetic substance may be provided thereon to eliminate a step due to the magnetic recording layer.
In this case, the transparent polymer layer may have the various functions described above.

Examples of the lubricant include silicone oil such as polysiloxane, plastic fine powder such as polyethylene and polytetrafluoroethylene, higher fatty acid, higher fatty acid ester, and fluorocarbons.
These can be used alone or as a mixture.
The amount of these additives is 0.2 to 100 parts by weight of the binder.
It can be used in the range of 20 parts by weight.

Examples of the abrasive include nonmagnetic inorganic powders having a Moth hardness of 5 or more, preferably 6 or more, and specifically, aluminum oxide (α-alumina, γ-alumina, corundum, etc.), Examples thereof include oxides such as chromium oxide (Cr ₂ O ₃ ) and iron oxide (α-Fe ₂ O ₃ ), silicon dioxide and titanium dioxide, carbides such as silicon carbide and titanium carbide, and fine powders such as diamond. The average particle size is preferably 0.05 to 1.0 μm, and the amount of the abrasive applied is 0.001 to 1 g / m ² , more preferably 0.003 to 0.5 g / m ² . .

After providing the magnetic recording layer, the layer is calendered to improve the smoothness, and the S / N of the magnetic output is increased.
It is also possible to improve the ratio. In this case, it is preferable to apply a silver halide photographic light-sensitive layer after the calendering treatment.

In the present invention, various supports can be used. As a support that can be used, a polyimide film obtained by reaction of pyromellitic acid or its anhydride with a diamine, a polyethylene film such as polyethylene terephthalate and polyethylene naphthalate, a cellulose triacetate film, a cellulose diacetate film, a polycarbonate film,
Examples include a polystyrene film and a polyolefin film.

The polyester support is not particularly limited, but aromatic dicarboxylic acids such as terephthalic acid, isophthalic acid, phthalic acid and naphthalenedicarboxylic acid and ethylene glycol, 1,3-propanediol, 1,4-
Condensation polymers with alkylene glycols such as butanediol include, for example, polyethylene terephthalate, polyethylene-2,6-dinaphthalate, polypropylene terephthalate, polybutylene terephthalate, and copolymers thereof.

In particular, Japanese Patent Application Laid-Open Nos. 1-244446, 1-291248, 1
-298350, 2-89045, 2-936
It is preferable to use a polyester having a high water content as shown in JP-A No. 41, 2-181747, 2-214852 and 2-291135.

These polyesters may have a polar group and other substituents.

When a polyimide film is used as the support, the polyimide is colored, so that it is necessary to make it thinner in order to obtain a necessary light transmission amount.

The support in the present invention is preferably a polyimide, polyethylene terephthalate, polyethylene naphthalate, cellulose triacetate, or a laminate of polyethylene terephthalate and polyethylene naphthalate.

The support is preferably stretched in an area ratio of 4 to 16 times in order to satisfy the mechanical strength and dimensional stability of the support.

In the present invention, the thickness of the support is from 14 to 74 μm. If it exceeds 74 μm and is 75 μm or more, errors in magnetic reproduction output increase. Also, 14 μm
Even if it is less than the above, the error of the magnetic reproduction output increases.

The support used in the present invention includes a matting agent,
Add antistatic agent, lubricant, surfactant, stabilizer, dispersant, plasticizer, ultraviolet absorber, conductive material, tackifier, softener, fluidity improver, thickener, antioxidant, etc. Then you can.

The support is used for the purpose of neutralizing the tint of the minimum density portion, preventing a light piping phenomenon (edge fogging) which occurs when light enters the film coated with the photographic emulsion layer from the edge, and preventing halation. Dyes can be included.

The type of the dye used is not particularly limited, but when a polyester film is used as a support,
In the film forming process, those having excellent heat resistance are preferable, for example,
Anthraquinone-based chemical dyes and the like can be mentioned. In addition, as for the color tone, when the purpose is to prevent light piping,
Gray dyeing is preferred as seen in general light-sensitive materials. The dyes may be used alone or in combination of two or more. Diaresi manufactured by Mitsubishi Chemical Corporation
The target can be achieved by using a dye such as MACROLEX (manufactured by Bayer Co.) alone or in an appropriate mixture.

The organic solvent used in the dispersion and coating of the present invention includes ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, isophorone and tetrahydrofuran in any ratio; methanol, ethanol, propanol, butanol and isobutyl. Alcohols such as alcohol, isopropyl alcohol and methylcyclohexanol; esters such as methyl acetate, ethyl acetate, butyl acetate, isobutyl acetate, isopropyl acetate, ethyl lactate and glycol monoethyl ether; diethylethyl, tetrahydrofuran, glycol dimethyl ether; Ethers such as glycol monoethyl ether and dioxane; benzene,
Tar-based (aromatic hydrocarbons) such as toluene, xylene, cresol, chlorobenzene, and styrene; chlorinated hydrocarbons such as methylene chloride, ethylene chloride, carbon tetrachloride, chloroform, ethylene chlorohydrin, and dichlorobenzene; N-dimethylformaldehyde,
Hexane and the like can be used.

It is preferable that 50% by weight or more of the organic solvent excluding water in the coating solution for a magnetic recording layer of the present invention is an organic solvent containing a ketone group.

The magnetic recording medium and the method of manufacturing the same according to the present invention include a black and white photosensitive material, a color negative photosensitive material, a color paper photosensitive material, a color reversal photosensitive material, a movie photosensitive material, an X-ray photosensitive material. Any photographic photosensitive material such as a material, a photosensitive material for printing, and a photosensitive material for microphotography may be used.

Any silver halide can be used as the silver halide in the silver halide emulsion, and examples thereof include silver bromide, silver iodide, silver chloride, silver iodobromide, silver chlorobromide, and silver chloroiodide. And silver chloroiodobromide, which are appropriately selected depending on the required performance, but silver bromide and silver iodobromide are preferable in that high sensitivity can be obtained.

The silver halide grains contained in the silver halide photographic emulsion to be used may be grains whose latent image is mainly formed on the surface or grains whose latent image is mainly formed inside the grain. .

The silver halide grains may have a regular crystal form such as cubic, octahedral or tetradecahedral,
It may have an irregular crystal form such as a sphere or a plate. In these particles, the (100) plane and the (111) plane
Any ratio of surfaces can be used. Further, those having a complex form of these crystal forms may be used, and grains of various crystal forms may be mixed, but twin silver halide grains having two opposite parallel twin planes are preferred. .

A twin is a silver halide crystal having one or more twin planes in one grain. The classification of twins is based on the report by Klein and Moiser in Photographic Corspondents. [Photographhishhe
Korespondenz] 99, 99, 10
It is described in detail in Vol.

In the present invention, when tabular silver halide grains are used, the average value of the ratio of the diameter to the thickness of the tabular grains (also referred to as the aspect ratio) is preferably less than 5, more preferably 1. It is 1 or more and less than 4.5, particularly preferably 1.2 or more and less than 4. This average value is obtained by averaging the ratio of the diameter to the thickness of all tabular grains.

The diameter of a silver halide grain is represented by a circle equivalent diameter of a projected area of the silver halide grain (diameter of a circle having the same projected area as the silver halide grain),
To 5.0 μm, more preferably 0.2 to 4.0 μm.
0 μm, particularly preferably 0.3 to 3.0 μm.

As the silver halide photographic emulsion, any emulsion such as a polydisperse emulsion having a wide grain size distribution and a monodisperse emulsion having a narrow grain size distribution can be used, but a monodisperse emulsion is preferred.

Here, the monodispersed silver halide emulsion includes:
It is preferable that the weight of silver halide contained in the range of ± 20% of the particle diameter of the center of the average particle diameter r is 60% or more of the total weight of silver halide grains, more preferably 70% or more,
It is more preferably at least 80%.

Here, the average particle size r is defined as the particle size ri at which the product ni × ri ³ of the frequency ni and ri ³ of the particles having the particle size ri becomes maximum.

Here, the particle diameter ri is a diameter when a projected image of silver halide grains is converted into a circular image having the same area.

The particle diameter ri can be obtained, for example, by photographing the particles with an electron microscope at a magnification of 10,000 to 70,000 and measuring the particle diameter or the area at the time of projection on the print (measurement). The number of particles is indiscriminately 1,000 or more.)

The particularly preferred highly monodispersed emulsion of the present invention has a distribution width defined by (standard deviation of particle size / average particle size) × 100 = width (%) of distribution. 20
%, More preferably 15% or less.

Here, the average particle diameter and the standard deviation are determined from the particle diameter ri defined above.

In the present invention, when silver iodobromide is used as the silver halide, the silver iodide content should be not less than 4 mol% and not more than 15 mol% as the average silver iodide content in the whole silver halide grains. %, More preferably 5 mol% or more and 12 mol% or less, and particularly preferably 6 mol% or more and 10 mol% or less.

The silver halide grains contained in the silver halide photographic emulsion are preferably so-called core / shell grains in which silver iodide is concentrated.

The core / shell type particles are particles composed of a core serving as a core and a shell covering the core, and the shell is formed by one or more layers. The silver iodide content of the core and the shell are preferably different from each other, and it is particularly preferable that the core and the shell are formed with the maximum silver iodide content.

The silver iodide content of the core is preferably at least 10 mol%, more preferably at least 20 mol%, and further preferably at least 25 mol%.
The silver iodide content of the outermost shell of the above-mentioned shells, that is, the shell which normally forms the outermost surface layer is preferably 5 mol% or less, more preferably 0 to 2 mol%. The proportion occupied by the core is desirably 2 to 60%, preferably 5 to 50%, of the total volume of the particles.

The silver halide particles contained in the silver halide photographic emulsion are prepared by pre-existing an aqueous solution and seed particles containing a protective colloid such as gelatin in a reaction vessel, and if necessary, silver ions, halide ions or silver halide fine particles. And the seed particles are grown by crystal growth. Here, the seed particles can be prepared by a single jet method or a controlled double jet method well known in the art. The halogen composition of the seed grains is optional, and may be any of silver bromide, silver iodide, silver chloride, silver iodobromide, silver chlorobromide, silver chloroiodide, and silver chloroiodobromide. Silver bromide and silver iodobromide are preferred.

When seed grains are used for preparing a silver halide emulsion, the seed grains may have a regular crystal form such as cubic, octahedral or tetradecahedral, or may have a spherical or plate-like shape. It may have an irregular crystal form. In these particles, any ratio can be used for the (100) plane and the (111) plane. Further, those having a composite form of these crystal forms may be used, and particles of various crystal forms may be mixed,
It is preferable to use monodisperse spherical seed particles described in the specification of Japanese Patent Application No. 2-408178.

The silver halide photographic emulsion can be produced by any of an acidic method, a neutral method and an ammonia method.

In the production of a silver halide photographic emulsion,
The halide ions and the silver ions may be mixed at the same time, or one of them may be mixed while the other is present. Also,
The growth may be carried out by sequentially or simultaneously adding halide ions and silver ions while controlling the pH and pAg in the mixing vessel while considering the critical growth rate of the silver halide crystals. The silver halide composition of the grains may be changed by using a conversion method in any step of silver halide formation. Further, halide ions and silver ions may be supplied as fine silver halide particles into the mixing vessel.

In the production of a silver halide photographic emulsion,
Known silver halide solvents such as ammonia, thioethers and thioureas can be present.

The silver halide grains contained in the silver halide photographic emulsion are subjected to cadmium salt, zinc salt, lead salt, thallium salt, iridium salt (including complex salt), Rhodium salts (including complex salts)
And at least one selected from iron salts (including complex salts) to add metal ions to allow these metal elements to be contained inside and / or on the surface of the particles, and to be placed in an appropriate reducing atmosphere. Thereby, reduction sensitization nuclei can be provided inside the grains and / or on the grain surfaces.

In the silver halide photographic emulsion, unnecessary soluble salts may be removed after the growth of the silver halide grains is completed, or may be kept contained. When removing the salts, use Research Disclosure (Resea).
rch Disclosure, hereinafter abbreviated as RD. ) N
o. No. 17643 No. II.

In the production of the silver halide photographic emulsion according to the present invention, conditions other than those described above are described in JP-A-61-6.
No. 643, No. 61-14630, No. 61-11214
No. 2, No. 62-157024, No. 62-18556
No. 63-92942, No. 63-151618,
Optimal conditions can be selected by referring to known methods such as those described in JP-A-63-163451, JP-A-63-220238, and JP-A-63-31244.

The silver halide emulsion can be subjected to physical ripening, chemical ripening and spectral sensitization. The additive used in such a process is RDNo. No. 17643, ibid.
No. 18716 and the same No. 308119 (hereinafter RD17643, RD18716 and RD308119, respectively)
Abbreviated. )It is described in. Table 1 shows the locations described.

[0100]

[Table 1]

When the magnetic recording medium of the present invention and the method for producing the same have a photographic light-sensitive material and the photographic light-sensitive material is a color photographic light-sensitive material, the photographic additives that can be used are those described in the above RD. Have been described. Table 2 shows the relevant descriptions.

[0102]

[Table 2]

The hardening agent is used in an amount of 1 to 20 with respect to dry gelatin.
%, Preferably 2 to 10% by weight.

When the magnetic recording medium and the method of manufacturing the same of the present invention have a photographic material and the photographic material is a color photographic material, various couplers can be used. Examples are RD17643 and R
D308119. Table 3 shows the relevant descriptions.

[0105]

[Table 3]

Further, these additives are referred to as RD308119.
It can be added to a photographic light-sensitive layer by a dispersion method described in section XIV on page 1007.

The color photographic light-sensitive material includes RD30
An auxiliary layer such as a filter layer or an intermediate layer described in section 8119 VII-K can be provided.

When a color photographic light-sensitive material is formed, various layer structures such as a forward layer, a reverse layer, and a unit structure described in the aforementioned RD308119 VII-K can be employed.

An undercoat layer may be provided on the support to firmly adhere, for example, a photosensitive silver halide emulsion layer, a filter layer, and a conductive layer. Surface activation treatment such as mechanical treatment, corona discharge treatment, flame treatment, ultraviolet treatment, high frequency treatment, glow discharge treatment, active plasma treatment, laser treatment, concentrated acid treatment, and ozone oxidation treatment may be performed. Further, after the surface activation treatment, an undercoat layer may be provided, and a photographic emulsion layer or the like may be coated thereon.

When the magnetic recording medium of the present invention and the method for producing the same have a photographic material, the silver halide photographic material can be developed by, for example, T.I. H. James, Theory of the Photographic Process 4th Edition (The Theory of The Pho
tough Process Forth Ed
Ition) pp. 291-334 and Journal of the American Chemical Society (Jo)
urnaI of the AmericanChem
Ical Society) Volumes 73 to 3,100
Known developers described on page (1951) can be used. Color photographic light-sensitive materials are described in RD17643, pp. 28-29, RD1871.
Development processing can be carried out by a usual method described on page 6 615 and RD308119 XIX.

[0111]

EXAMPLES Hereinafter, the present invention will be described specifically with reference to Examples, but the present invention is not limited thereto.

Example 1 (Preparation of Magnetic Recording Medium 1) << Preparation of Support >> 100 parts by weight of dimethyl 2,6-naphthalenedicarboxylate and 60 parts by weight of ethylene glycol were mixed with 0.1 parts of calcium acetate hydrate as a transesterification catalyst. A part by weight was added, and a transesterification reaction was performed according to a conventional method.
To the obtained product, 0.05 parts by weight of antimony trioxide,
0.03 parts by weight of trimethyl phosphate was added.
Then, gradually raise the temperature and reduce the pressure, 290 ° C, 0.05 mm
Polymerization was performed under Hg conditions to obtain polyethylene-2,6-naphthalate having an intrinsic viscosity of 0.60.

This was vacuum-dried at 150 ° C. for 8 hours, melt-extruded in a layer form from a T-die at 300 ° C., brought into close contact with a cooling drum at 50 ° C. while applying static electricity, cooled and solidified, and an unstretched sheet was formed. Obtained. This unstretched sheet was stretched 3.3 times in the machine direction at 135 ° C. using a roll-type longitudinal stretching machine.

The obtained uniaxially stretched film was stretched in a first stretching zone at 145 ° C. by 50% of the total transverse stretching ratio using a tenter type transverse stretching machine, and further at a second stretching zone at 155 ° C. at a total transverse stretching ratio of 3. The film was stretched three times. Then 10
Heat treated at 0 ° C for 2 seconds, and further heat-fixed zone 200 ° C
For 5 seconds and a second heat setting zone at 240 ° C. for 15 seconds. Next, the film was gradually cooled to room temperature over 30 seconds while performing a 5% relaxation treatment in the lateral direction to obtain a polyethylene naphthalate film having a thickness of 85 μm.

This is wound around a stainless steel core, and
A heat treatment (annealing treatment) was performed at 10 ° C. for 48 hours to produce a support.

On both sides of this support, 12 W / m ² / min
On one side, the following undercoating coating solution B
-1 is applied so as to have a dry film thickness of 0.4 μm, and a corona discharge treatment of 12 W / m ² / min is applied thereon, so that the undercoating coating solution B-2 described below has a dry film thickness of 0.06 μm. Was applied.

On the other surface subjected to the corona discharge treatment of 12 W / m ² / min, the following undercoating coating solution B-3 was applied to a dry film thickness of 0.2 μm, and 12 W / m ² / min. ^Two
/ Min corona discharge treatment and the following undercoating coating solution B-
4 was applied to a dry film thickness of 0.2 μm.

Each of the layers was dried at 90 ° C. for 10 seconds after the application, and after the four layers were applied, heat-treated at 110 ° C. for 2 minutes, and then cooled at 50 ° C. for 30 seconds.

<Undercoat Coating Solution B-1> A copolymer latex liquid of 30% by weight of butyl acrylate, 20% by weight of t-butyl acrylate, 25% by weight of styrene and 25% by weight of 2-hydroxyethyl acrylate (solid content: 30% 125 g Compound (UL-1) 0.4 g Hexamethylene-1,6-bis (ethylene urea) 0.05 g Finish with water 1000 ml <Subbing coating solution B-2> Hydroxidation of styrene-maleic anhydride copolymer Sodium aqueous solution (solid content 6%) 50 g Compound (UL-1) 0.6 g Compound (UL-2) 0.09 g Silica particles (average particle size 3 μ) 0.2 g Finished with water 1000 ml <Undercoat coating solution B-3 > 30% by weight of butyl acrylate, 20% by weight of t-butyl acrylate, 25% by weight of styrene and 2-hydroxyacrylate 25% by weight copolymer latex liquid (solid content 30%) 50g Compound (UL-1) 0.3g Hexamethylene-1,6-bis (ethylene urea) 1.1g Finish with water 1000ml

[0120]

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<Subbing Coating Solution B-4> 60 mol% of dimethyl terephthalate, 30 mol% of dimethyl isophthalate, 10 mol% of sodium salt of dimethyl 5-sulfoisophthalate, 50 mol of ethylene glycol as glycol component % And diethylene glycol 50 mol% were copolymerized by a conventional method. The copolymer was stirred in hot water at 95 ° C. for 3 hours to obtain a 15% by weight aqueous dispersion A.

Water dispersion (solid content: 40% by weight) of tin oxide-antimony oxide composite fine particles (average particle size: 0.2 μm) 109 g Water dispersion A 67 g Finished with water 1000 ml << Coating of magnetic recording layer >> Subtraction B-4 of processing support
A magnetic recording layer coating solution having the following composition was coated on the layer coated with the coating solution using a precision extrusion coater to a magnetic substance weight of 60.
mg / m ² , and at the same time as drying, the magnetic material is oriented in the application direction in an orientation magnetic field while the coating film is still wet,
Higher output during magnetic recording and reproduction was achieved.

Further, 10 mg / m ² of carnauba wax was applied on the magnetic recording layer to obtain a magnetic recording medium described later.

Next, the magnetic recording medium was wound and heated at 60 ° C. for 4 days to obtain a magnetic recording medium 1.

(Preparation of Magnetic Recording Layer Coating Solution 1) Magnetic recording layer coating solution 1 was prepared as follows. The magnetic substance, aluminum oxide, and silica were separately dispersed in diacetylcellulose, and after the remaining diacetylcellulose was added, they were dispersed uniformly, and tolylene diisocyanate was further added.
Thereafter, as shown in Table 1, before the coating, a water-containing liquid which was previously uniformly mixed in an organic solvent was added to obtain a magnetic recording layer coating liquid 1.

Magnetic material 5 parts by weight (Co-coated γ-Fe ₂ O ₃ , coercive force 900 Oe, surface area 40 m ² / g major axis 0.15 μm, minor axis 0.03 μm) diacetyl cellulose (acetic acid value 55%, (Mw = 180,000) 70 parts by weight Aluminum oxide (average particle diameter 0.4 μm) 4 parts by weight Silica (average particle diameter 0.3 μm) 3 parts by weight Tolylene diisocyanate 8 parts by weight Acetone 834 parts by weight Methanol 357 parts by weight Water 4 parts by weight (Preparation of Magnetic Recording Layer Coating Solutions 2 to 22) The magnetic recording layer was prepared in exactly the same manner as the magnetic recording layer coating solution 1 except that the binder, the crosslinking agent, the water, and the organic solvent were changed as shown in Table 4 below. Coating solutions 2 to 22 were obtained. Then, magnetic recording media 2 to 22 were obtained in exactly the same manner as the magnetic recording medium 1 except that the magnetic recording layer and the coating liquid 1 were changed to 2 to 22.

[0127]

[Table 4]

[Type of Binder] A: Diacetylcellulose (acetic acid value 55%, Mw = 18)
B): Polyester urethane (Mw = 25,000) C: Diacetyl cellulose (acetic acid value 55%, Mw = 10)
D): Polyvinyl chloride (Mw = 40,000) E: Cellulose acetate butyrate (Mw = 70,000) F: Cellulose acetate propionate (Mw = 25)
[Crosslinking agent type] a: Tolylene diisocyanate b: Hexamethylene diisocyanate c: 4,4-diphenylmethane diisocyanate d: Hexamethylene-1,6-bis (ethylene urea) e: Sumimal M-40S (Sumitomo Chemical Industries, Ltd. [Addition method] A: Water is directly added to the magnetic recording layer coating solution after the addition of the crosslinking agent, followed by stirring.

B: Water is added to a liquid having the same organic solvent ratio as the magnetic recording layer coating liquid after the addition of the cross-linking agent, mixed uniformly, and then added to the magnetic recording layer coating liquid.

[Type of Organic Solvent] a: Acetone b: Methanol c: Toluene d: Methyl ethyl ketone e: Cyclohexanone
After a heat treatment for 3 days, a magnetic recording medium 23 was obtained. After the magnetic recording medium 1 is subjected to a heat treatment, the magnetic recording medium 1 is further heated to 60 ° C. and 50%
H, heat treatment was performed for 3 days to obtain a magnetic recording medium 24.

An undercoat layer coated with the undercoat coating solutions B-1 and B-2 under the same conditions is provided on the opposite side of the magnetic recording medium from the magnetic recording layer side. Samples 1 to 24 were obtained by providing a photographic component layer having the composition. 1 m ²
Expressed in grams per unit. However, silver halide and colloidal silver were converted to the amount of silver, and the sensitizing dye (indicated by SD) was silver 1
It was shown in moles per mole.

First Layer (Antihalation Layer) Black Colloidal Silver 0.16 UV-1 0.3 CM-1 0.044 OIL-1 0.044 Gelatin 1.33 Second Layer (Intermediate Layer) AS-10 .16 OIL-1 0.20 Gelatin 1.40 Third layer (low-sensitivity red-sensitive layer) Silver iodobromide a 0.12 Silver iodobromide b 0.50 SD-1 3.0 × 10 ^-5 SD-4 1.5 × 10 ^-4 SD-3 3.0 × 10 ^-4 SD-6 3.0 × 10 ^-6 C-1 0.51 CC-1 0.047 OIL-2 0.45 AS- 2 0.005 Gelatin 1.40 4th layer (medium-speed red-sensitive layer) Silver iodobromide c 0.64 SD-1 3.0 × 10 ^-5 SD-2 1.5 × 10 ^-4 SD- ^{3 3.0 × 10 -4 C-2} 0.22 CC-1 0.028 DI-1 0.002 OIL-2 0.21 AS-3 0.006 Zera Down 0.87 Fifth Layer (high sensitivity red-sensitive layer) Silver iodobromide c 0.13 Silver iodobromide d 1.14 SD-1 3.0 × 10 -5 SD-2 1.5 × 10 ^-4 SD-3 3.0 × 10 ^-4 C-2 0.085 C-3 0.084 CC-1 0.029 DI-1 0.027 OIL-2 0.23 AS-3 0.013 Gelatin 1 .23 6th layer (intermediate layer) OIL-1 0.29 AS-1 0.23 gelatin 1.00 7th layer (low-sensitivity green color-sensitive layer) Silver iodobromide a 0.245 Silver iodobromide b 0.105 SD-6 5.0 × 10 ^-4 SD-5 5.0 × 10 ^-4 M-1 0.21 OIL-1 0.25 AS-2 0.003 AS-4 0.063 Gelatin 0. 98 8th layer (intermediate layer) M-1 0.03 CM-2 0.005 OIL-1 0.16 AS-1 0.11 gelatin 0.80 9th layer (middle Sensitive green color-sensitive layer) Silver iodobromide e 0.87 SD-7 3.0 × 10 ^-4 SD-8 6.0 × 10 ^-5 SD-9 4.0 × 10 ^-5 M-10. 17 CM-2 0.048 CM-3 0.059 DI-2 0.012 OIL-1 0.29 AS-4 0.05 AS-2 0.005 Gelatin 1.43 10th layer (high sensitive green color sensitivity) Silver iodobromide f 1.19 SD-7 4.0 × 10 ^-4 SD-8 8.0 × 10 ^-5 SD-9 5.0 × 10 ^-5 M-1 0.09 CM-3 0.020 DI-3 0.005 OIL-1 0.11 AS-4 0.026 AS-5 0.014 AS-6 0.006 Gelatin 0.78 11th layer (yellow filter layer) Yellow colloidal silver 05 OIL-1 0.18 AS-7 0.16 Gelatin 1.00 12th layer (low-sensitivity blue-sensitive layer) Silver iodobromide g 0 .29 Silver iodobromide h 0.19 SD-10 8.0 × 10 ^-4 SD-11 3.1 × 10 ^-4 Y-1 0.91 DI-4 0.022 OIL-1 0.37 AS- 2 0.002 Gelatin 1.29 13th layer (high-sensitivity blue-sensitive layer) Silver iodobromide h 0.13 Silver iodobromide i 1.00 SD-10 4.4 × 10 ^-4 SD-11 1 0.5 × 10 ^-4 Y-1 0.48 DI-4 0.019 OIL-1 0.21 AS-2 0.004 Gelatin 1.55 Fourteenth layer (first protective layer) Silver iodobromide j 0. 30 UV-1 0.055 UV-2 0.110 OIL-2 0.63 Gelatin 1.32 15th layer (second protective layer) PM-1 0.15 PM-2 0.04 WAX-1 0.02 D-1 0.001 gelatin 0.55 In addition to the above composition, coating aids SU-1 and SU-
2, SU-3, dispersing aid SU-4, viscosity modifier V-1,
Stabilizers ST-1, ST-2, antifoggant AF-1, weight average molecular weight: 10,000 and weight average molecular weight: 1,
100,000 two types of polyvinylpyrrolidone (AF-
2), inhibitors AF-3, AF-4, AF-5, hardener H
-1, H-2 and the preservative Ase-1 were added.

The structure of the compound used in the above sample is shown below.

Table 5 shows the characteristics of the silver iodobromide.

[0135]

[Table 5]

[0136]

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[0137]

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[0138]

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[0139]

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[0140]

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[0141]

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[0142]

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[0143]

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[0144]

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Incidentally, as a preferred example of forming silver halide grains of the present invention, an example of the production of silver iodobromide d and f is shown below.

(Preparation of seed crystal emulsion-1) A seed crystal emulsion was prepared as follows.

JP-B-58-58288, 58-58
No. 289, a silver nitrate aqueous solution (1.161 mol) was added to the following solution A1 adjusted to 35 ° C.
And a mixed aqueous solution of potassium bromide and potassium iodide (potassium iodide 2 mol%) while maintaining the silver potential (measured with a silver ion selective electrode using a saturated silver-silver chloride electrode as a reference electrode) at 0 mV. For 2 minutes to form nuclei. Subsequently, the temperature of the solution was raised to 60 ° C. over a period of 60 minutes, the pH was adjusted to 5.0 with an aqueous solution of sodium carbonate, and then an aqueous solution of silver nitrate (5.902 mol), potassium bromide and iodide were added. A mixed aqueous solution of potassium (2 mol% of potassium iodide) was added over 42 minutes by a double jet method while keeping the silver potential at 9 mV. After the addition was completed, the temperature was lowered to 40 ° C., and desalting and washing were immediately performed using a normal flocculation method.

The resulting seed crystal emulsion had an average sphere-equivalent diameter of 0.24 μm, an average aspect ratio of 4.8, and 90% or more of the total projected area of the silver halide grains had a maximum side ratio of 1.0.
~ 2.0 hexagonal tabular grains.
This emulsion is referred to as seed emulsion-1.

[Solution A1] Ossein gelatin 24.2 g Potassium bromide 10.8 g HO (CH ₂ CH ₂ O) _m (CH (CH ₃ ) CH ₂ O) _19.8 (CH ₂ CH ₂ O) _n H (m + n = 9.77) (10% ethanol solution) 6.78 mL 10% nitric acid 114ml H ₂ O 9657ml (preparation of silver iodide fine grain emulsion SMC-1) of 6.0% by weight containing 0.06 mol of potassium iodide While vigorously stirring 5 liters of an aqueous gelatin solution, 2 liters of a 7.06 mol aqueous solution of silver nitrate and a 7.06 mol aqueous solution of potassium iodide were added over 10 minutes. During this time, the pH was controlled at 2.0 using nitric acid, and the temperature was controlled at 40 ° C. After the preparation of the particles, the pH was adjusted to 5.0 using an aqueous sodium carbonate solution. The average particle size of the obtained silver iodide fine particles is 0.05 μm.
Met. This emulsion is designated as SMC-1.

(Preparation of silver iodobromide d) Seed emulsion-1 equivalent to 0.178 mol and HO (CH ₂ CH ₂ O) _m (CH (C
H ₃ ) CH ₂ O) _19.8 (CH ₂ CH ₂ O) _n H (m + n =
9.77) containing 0.5 ml of a 10% ethanol solution.
700 ml of a 4.5% by weight aqueous inert gelatin solution is added to 75
C., the pAg was adjusted to 8.4 and the pH to 5.0, and then particles were formed by the simultaneous mixing method with vigorous stirring by the following procedure.

1) 2.1 mol silver nitrate aqueous solution and 0.19
5 mol of SMC-1 and an aqueous solution of potassium bromide were added to pA
g while maintaining the pH at 8.4 and the pH at 5.0.

2) Subsequently, the temperature of the solution was lowered to 60 ° C., and pAg
Was adjusted to 9.8. Then, 0.071 mol of SMC
-1 was added and aging was performed for 2 minutes (introduction of dislocation lines).

3) 0.959 mol of silver nitrate aqueous solution and 0.
03 mol of SMC-1 and an aqueous solution of potassium bromide were added to p
Ag was added at 9.8 and the pH was maintained at 5.0.

Each solution was added at an optimum rate throughout the particle formation so that the formation of new nuclei and the Ostwald ripening between particles did not proceed. After completion of the addition, the resultant was subjected to a water washing treatment at 40 ° C. using a normal flocculation method, and then gelatin was added and redispersed to adjust the pAg to 8.1 and the pH to 5.8.

The obtained emulsion had a particle size (cubic 1 of the same volume).
The emulsion was composed of tabular grains having a halogen composition of 0.75 μm in side length, an average aspect ratio of 5.0, and a halogen composition of 2 / 8.5 / X / 3 mol% (X is a dislocation line introduction position) from the inside of the grains. . When this emulsion was observed with an electron microscope, five or more dislocation lines were observed both in the fringe portion and in the inside of the grain in 60% or more of the total projected area of the grain in the emulsion. The surface silver iodide content was 6.7 mol%.

(Preparation of silver iodobromide f) In the preparation of silver iodobromide d, the pAg was set to 8.8 in step 1), the amount of silver nitrate added in step 3) was 0.92 mol, and SMC- Silver iodobromide f was prepared in exactly the same manner as silver iodobromide d except that the amount of 1 was changed to 0.069 mol.

The obtained emulsion had a particle size (cubic 1 of the same volume).
An emulsion comprising tabular grains having a halogen composition of 0.65 μm, an average aspect ratio of 6.5, and a halogen composition of 2 / 8.5 / X / 7 mol% (X is a dislocation line introduction position) from the inside of the grains. . When this emulsion was observed with an electron microscope, five or more dislocation lines were observed both in the fringe portion and in the inside of the grain in 60% or more of the total projected area of the grain in the emulsion. The surface silver iodide content was 11.9 mol%.

After the above-mentioned sensitizing dyes were added to each of the above emulsions and ripened, triphosphine selenide, sodium thiosulfate, chloroauric acid and potassium thiocyanate were added, and fogging and sensitivity were optimized according to a conventional method. Chemical sensitization was applied to obtain.

Silver iodobromide a, b, c, e, g, h, i, j
Was also subjected to spectral sensitization and chemical sensitization according to d and f above.

As described above, magnetic recording media 1 to 24 having a photographic photosensitive material were obtained.

Comparative Example A magnetic recording layer coating solution 23 was obtained in exactly the same manner as the magnetic recording layer coating solution 1 except that the magnetic recording layer coating solution 1 did not contain water. A magnetic recording medium 25 having a photographic material was obtained in exactly the same manner as in Example 1.

(Wet development processing) Image exposure was performed on the photographic constituent layers, and the following wet development processing was performed for the magnetic head clogging evaluation test (developed), head dirt microscopic observation, coating film durability, which will be described later. Tested.

(Processing step) Processing step Processing time Processing temperature Replenishment amount * Color development 3 minutes 15 seconds 38 ± 0.3 ° C. 780 ml Bleaching 45 seconds 38 ± 2.0 ° C. 150 ml Fixing 1 minute 30 seconds 38 ± 2. 0 ° C. 830 ml Stability 60 seconds 38 ± 5.0 ° C. 830 ml Drying 1 minute 55 ± 5.0 ° C.-* The replenishing amount is a value per 1 m ² of the photosensitive material.

The following color developing solutions, bleaching solutions, fixing solutions, stabilizing solutions and replenishers were used.

Color developing solution and color developing replenishing solution Developer replenishing solution Water 800 ml 800 ml Potassium carbonate 30 g 35 g Sodium bicarbonate 2.5 g 3.0 g Potassium sulfite 3.0 g 5.0 g Sodium bromide 1.3 g 0.4 g iodide Potassium 1.2 mg-Hydroxylamine sulfate 2.5 g 3.1 g Sodium chloride 0.6 g-4-Amino-3-methyl-N-ethyl-N-([beta] -hydroxylethyl) aniline sulfate 4.5 g 6.3 g Diethylenetriaminepentaacetic acid 3.0 g 3.0 g Potassium hydroxide 1.2 g 2.0 g Add water to make 1 liter, and add potassium hydroxide or 20%
The color developing solution is adjusted to pH 10.06 and the replenisher is adjusted to pH 10.18 using sulfuric acid.

Bleaching Solution and Bleaching Replenisher Bleaching Solution Replenisher Water 700 ml 700 ml 1,3-diaminopropanetetraacetate ammonium (III) ammonium 125 g 175 g ethylenediaminetetraacetic acid 2 g 2 g sodium nitrate 40 g 50 g ammonium bromide 150 g 200 g glacial acetic acid 40 g 56 g water To 1 liter, and adjust the pH of the bleaching solution to 4.4 and the pH of the replenishing solution to 4.0 using ammonia water or glacial acetic acid.

Fixing solution and fixing replenisher Fixing solution Replenisher Water 800 ml 800 ml Ammonium thiocyanate 120 g 150 g Ammonium thiosulfate 150 g 180 g Sodium sulfite 15 g 20 g Ethylenediaminetetraacetic acid 2 g 2 g Aqueous solution using ammonia water or glacial acetic acid, pH 6.2
Then, the pH of the replenisher is adjusted to 6.5, and then water is added to make 1 liter.

Stabilizing Solution and Stabilizing Replenisher Water 900 ml p-octylphenol ethylene oxide 10 mol adduct 2.0 g dimethylolurea 0.5 g hexamethylenetetramine 0.2 g 1,2-benzoisothiazolin-3-one 0.1 g siloxane (UCC L-77) 0.1 g ammonia water 0.5 ml water was added to make up to 1 liter.
Adjust to pH 8.5 with% sulfuric acid.

<< Evaluation Method >> Magnetic head clogging evaluation test A magnetic recording medium having the photographic photosensitive material described above
6KH is applied to each sample cut to inch width and length 50m.
A z-wave signal was recorded at a transport speed of 100 mm / S.

Next, the above sample was subjected to the above development processing. The composition of the processing solution used in each step is as described above.

Next, the square waveform signal was read at the same speed by the magnetic read head, and the number of reproduction errors when the output became 35% or less of the initial value was evaluated.

Reproduction error: pulse output is 35% of initial value
The phenomenon that became below. The same phenomenon of 100 pulses or less is counted as one.

2. Observation of Head Stain Microscope The head used above was removed, and the stain condition of the surface was observed under a microscope, and the results were classified into the following grades and evaluated.

Dirt on the entire surface: × 50% or more of dirt on the head: Δ Dirt on the head, 10% or less: ○ 3. Durability of Magnetic Layer Using HEIDON-14DR (manufactured by Shinto Kagaku Co., Ltd.), the film was repeatedly worn for 100 passes at a head load of 300 g and a speed of 100 mm / s.

Scratched state None: ○ Weak scratch: Δ Strong scratch: × 4. Water content of coating solution for magnetic recording layer Measured by Karl Fischer moisture meter.

The results of the above evaluation are shown in Table 6.

[0177]

[Table 6]

[0178] Except for the magnetic recording coating solution 23, all were adjusted to 3
Even after a lapse of days, there was no increase in viscosity and the stability was good. In addition, there was no problem at all such as coating failure or clogging of process piping.

As is evident from Table 6, by adding water to the coating solution for the magnetic recording layer of the present invention so as to contain the magnetic head, clogging of the magnetic head, contamination of the magnetic head, and the like even after the wet development processing were performed.
An excellent magnetic recording medium with improved durability of the coating film can be obtained.In particular, the method of adding water to the coating solution is to uniformly add water to the organic solvent constituting the coating solution, and thereafter, To prepare a coating solution for a magnetic recording layer to obtain further performance.

[0180]

According to the present invention, it is possible to firstly provide head cleaning properties to reduce clogging of a magnetic head after wet development processing, and secondly to provide a magnetic recording medium with less head contamination. Third, by sufficiently crosslinking the binder and the crosslinking agent in the magnetic layer, it was possible to provide a magnetic recording medium having improved scratch resistance and durability of the coating film.

Claims (7)

[Claims] 1. A method for producing a magnetic recording medium having a magnetic recording layer on a support, wherein water is added to and mixed with the magnetic recording layer coating solution. 2. The method for producing a magnetic recording medium according to claim 1, wherein the amount of water contained in the coating solution for the magnetic recording layer is 0.3 to 20% by weight based on the weight of the coating solution. 3. The method for adding water to a coating solution for a magnetic recording layer according to claim 1 or 2, wherein water is added to an organic solvent constituting the coating solution, mixed uniformly, and then added. A method for producing a magnetic recording medium, comprising preparing a coating solution. 4. The organic solvent having a ketone group content of 50% by weight or more of the organic solvent excluding water in the coating solution for a magnetic recording layer. A method for manufacturing a magnetic recording medium. 5. The magnetic recording medium according to claim 1, wherein the binder in the magnetic recording layer is a cellulose ester. 6. The magnetic recording medium according to claim 5, wherein said cellulose ester is diacetyl cellulose. 7. The magnetic recording medium according to claim 5, wherein the binder in the magnetic recording layer has a weight average molecular weight of 20,000 to 300,000.