JPH06139545A - Long-sized magnetic recording medium and its production - Google Patents

Abstract

PURPOSE:To obtain a long-sized magnetic recording medium excellent in running durability by ensuring below a prescribed difference each in glossiness and roughness Ra between the front and rear ends of the magnetic layer of a long- sized magnetic recording medium per 100m. CONSTITUTION:A magnetic layer contg. ferromagnetic fine powder and a binder is formed on a nonmagnetic base material, calendered and heat-treated so as to ensure <0.1% difference in glossiness and <0.02nm difference in roughness Ra between the front and rear ends of the magnetic layer of the resulting long- sized magnetic recording medium per 100m. A difference in quality in the longitudinal direction of the magnetic recording medium is eliminated, the objective long-sized magnetic recording medium excellent in running durability such as wear resistance and frictional characteristics is obtd. and unevenness between lots is reduced.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a long magnetic recording medium comprising a magnetic layer and a non-magnetic support, and more specifically, it improves head wear and head contact in a VTR and maintains high output. , A long magnetic recording medium having a magnetic layer which suppresses head contamination of a VTR and has excellent running stability, and a method for manufacturing the same.

[0002]

2. Description of the Related Art Generally, as a magnetic recording medium for audio, video, computer (memory tape), etc., a magnetic layer having ferromagnetic fine powder dispersed in a binder is provided on a non-magnetic support. Magnetic recording media are used. Conventionally, these magnetic recording media have been used as a magnetic layer containing ferromagnetic fine powder, a binder, and an abrasive having a Mohs hardness of 8 or more. Of these, the abrasives in particular have suppressed head contamination on the VTR and have always provided the best image, sound and data recording. Various abrasives have been proposed for this purpose and are disclosed in Japanese Examined Patent Publication No. 49-39402, Japanese Unexamined Patent Publication No. 57-183628, U.S. Pat. No. 3,630,910, Japanese Unexamined Patent Publication No. 57-179945 and the like. recent years,
High density recording is required for these magnetic recording media, and high reproduction output / noise and low noise due to ultra-smoothness of the surface of the magnetic recording media, finer ferromagnetic powder, metal powder, and high filling. There is a demand for thinning of magnetic recording media. In addition, in order to improve the recording density and the image quality, the writing speed and the calling speed to the magnetic recording medium in the VTR are shortened, the recording method (analog method to digital method) is changed, and the recording width is decreased (5 to 20 nm). ) And the shortest recording wavelength (0.1 to 0.9 μm) are required, and the head cylinder speed is 5400 RP in the helical scan VTR.
M or more, and the relative speed between the tape and the head is 20 m / s
ec is going to be far exceeded. In order to provide the magnetic recording medium with such high output and high-speed sliding suitability, it is essential to secure traveling stability in the VTR traveling system, head and cylinder system. In addition to the abrasives described above, various lubricants such as carbon black and organic compounds are used.

The major problems with these magnetic recording media are:
It is compatible with VTR heads, cylinders, and various guides inside the VTR. When attempting to achieve thinning and super smoothing for high density recording, it is extremely difficult to uniformly reduce the friction coefficient in the longitudinal direction of the tape with respect to the VTR head. When the friction coefficient increases, the surface of the magnetic layer is scraped off and the head becomes dirty. For this reason, the above-mentioned abrasive is added to the magnetic layer. However, in the case of manufacturing a long magnetic recording medium having a length of 1000 m or more in the longitudinal direction in the manufacturing process, the length of the long magnetic recording medium should be the same as that at the beginning. If the wear resistance and the friction coefficient are adjusted to the VTR, those characteristics cannot be obtained at the end portion of the long magnetic recording medium. Further, if the wear resistance and the friction coefficient of the end of the long magnetic recording medium in the longitudinal direction are adjusted to the VTR, those characteristics cannot be obtained at the head of the long magnetic recording medium. For example, in Japanese Examined Patent Publication No. 55-29501, in a method for producing a magnetic tape by applying a magnetic layer on the surface of a plastic base and then subjecting it to a super calender treatment and a cutting treatment, a super calender treatment is used. After that, a method for manufacturing a magnetic tape is disclosed, which comprises subjecting the magnetic tape to a heat treatment. However, it has been found that when such a heat treatment is performed, there is a significant difference in the characteristics and physical properties between the head portion and the end portion of the above-mentioned long magnetic recording medium.

In order to deal with such a problem, the conventional technique has no effective means for ensuring the friction coefficient with the VTR head, the cylinder, and various guides in the VTR in the longitudinal direction of the long magnetic recording medium. If dare to do so, adding an excessive amount of abrasive or inorganic powder such as carbon to the magnetic layer is effective in securing the friction coefficient and head wear.
However, when such an amount is added, the output of the long magnetic recording medium is significantly reduced, and when an inorganic powder is added in an amount that does not deteriorate the electromagnetic conversion characteristics, it becomes difficult to secure the friction coefficient and head wear. It was

[0005]

SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to provide a long magnetic recording medium which is excellent in electromagnetic conversion characteristics in high output / high density recording and has extremely excellent running durability. . In particular, the present invention eliminates the quality difference in the longitudinal direction of a long magnetic recording medium, has little variation between lots, and is extremely excellent in running durability such as wear characteristics and friction characteristics, and a manufacturing method thereof. The purpose is to provide.

[0006]

Therefore, the inventors of the present invention diligently studied the calendar treatment and the heat treatment, and when the heat treatment was performed, the characteristics at the leading end portion and the end portion of the above-mentioned long magnetic recording medium were investigated. As a result of diligent examination as to whether or not there is a significant difference in physical properties, the inventors have found that the tightening force due to heat treatment greatly differs between the wound roll core side and the wound roll core side, leading to the present invention. That is, the above object of the present invention is to provide a magnetic layer containing ferromagnetic fine powder and a binder on a non-magnetic support, and heat-treat it after calendering. This can be achieved by a long magnetic recording medium characterized in that the difference in glossiness between the magnetic layer at the beginning and the end at 100 m of the medium is less than 0.1% and the Ra difference is less than 0.02 nm. Preferably, the above object of the present invention is a long magnetic recording medium in which a magnetic layer containing a ferromagnetic fine powder and a binder is provided on a non-magnetic support, and heat treatment is performed after the calender treatment.
A long magnetic recording medium after the heat treatment, in which the magnetic layer on the roll core side has a rougher surface (Ra) and lower gloss than the outer magnetic layer in a state of being wound around a roll after the heat treatment. 100
This can be achieved by a long magnetic recording medium characterized in that the difference in glossiness between the top and the end of the magnetic layer per m is less than 0.1% and the difference in Ra is less than 0.02 nm. Such a long magnetic recording medium of the present invention can be obtained by the following two methods. That is, one is to provide a magnetic layer containing ferromagnetic fine powder and a binder on a non-magnetic support, carry out calendering treatment, and then heat the obtained long magnetic recording medium at 40 ° C. or more for 4 hours or more. In the method for producing a long magnetic recording medium, the method for producing a long magnetic recording medium, characterized in that in the calendering process, the calender pressure is temporarily increased from the beginning to the end of one roll, preferably The calender pressure is set to 200 kg / cm to 350 kg / cm at the beginning of one roll and is raised for a while, and the calender pressure is set to 2 at the end.
It can be obtained by a method for producing a long magnetic recording medium characterized in that the pressure difference is 20 kg / cm to 400 kg / cm and the pressure difference is 20 kg / cm to 200 kg / cm. Another method is to provide a magnetic layer containing a ferromagnetic fine powder and a binder on a non-magnetic support, carry out calendering treatment, and then prepare a long magnetic recording medium 40
In the method for producing a long magnetic recording medium, which comprises performing heat treatment at 4 ° C. or higher for 4 hours or longer, in the calendar treatment, 1
A method for producing a long magnetic recording medium, characterized in that the calender temperature is raised from the beginning to the end of one roll for a while, preferably, the calender temperature is set to 50 ° C. to 100 ° C. at the beginning of the one roll. Raise it,
At the end, the calender temperature is set to 60 ° C. to 110 ° C., and the temperature difference is set to 5 ° C. to 40 ° C., which is a method for manufacturing a long magnetic recording medium.

That is, the long magnetic recording medium of the present invention is
In a long magnetic recording medium, a magnetic layer containing ferromagnetic fine powder and a binder is provided on a non-magnetic support, and in the long magnetic recording medium, the difference in glossiness between the top and the end of the magnetic layer per 100 m of the long magnetic recording tape is 0. By adjusting the Ra difference to less than 1% and the Ra difference to less than 0.02 nm, it is possible to obtain a long magnetic recording medium having high output / high density recording and extremely excellent running durability in the tape longitudinal direction. Further, in a long magnetic recording medium in which a magnetic layer containing a ferromagnetic fine powder and a binder is provided on a non-magnetic support, the difference in glossiness between the magnetic layer at the beginning and the end at 100 m of the long magnetic recording tape is 0. Less than 0.1%, Ra difference 0.02n
By the production method of less than m, it is possible to obtain a long magnetic recording medium having high output / high density recording and extremely excellent running durability in the tape longitudinal direction. Further, the present invention provides a long magnetic recording medium which eliminates quality differences in the longitudinal direction of the long magnetic recording medium, has little variation between lots, and has extremely excellent running durability such as wear characteristics and friction characteristics. it can. When one roll is subjected to calendering treatment in the manufacturing process of the long magnetic recording medium, the calender pressure is temporarily increased or the calender temperature is temporarily increased from the start stage to the end stage, so that the tape longitudinal direction is increased.
It is possible to obtain a long magnetic recording medium with high output and high density recording and extremely excellent running durability.

When a long magnetic recording medium is heat-treated at 40 ° C. or more for 4 hours or more, the roll core side has a rougher surface and lower gloss than the outer side, and after heat treatment, the roll core side and the outer surface have By making substantially no difference in glossiness, it is possible to obtain a long magnetic recording medium having high output / high density recording and extremely excellent running durability in the tape longitudinal direction. Further, in the present invention, it is possible to eliminate the quality difference in the longitudinal direction of the long magnetic recording medium, to obtain a long magnetic recording medium which has little variation between lots and is extremely excellent in running durability such as wear characteristics and friction characteristics. You can In other words, the present invention considers winding tightening due to heat treatment in a bulk rolled state, and at the time of calendering, the leading portion, that is, the one on the core side, has a roughened surface property in advance, and the outer portion, that is, the end portion. The part is made smooth so that it is uniform in the finished state.

Hereinafter, each long magnetic recording medium of the present invention will be sequentially described in detail. The long magnetic recording medium of the present invention has a basic structure in which a magnetic layer containing at least ferromagnetic fine powder and a binder is coated on a non-magnetic support. In the long magnetic recording medium of the present invention, the magnetic layer may contain various solid or liquid abrasives or lubricants, and the non-magnetic support provided with the magnetic layer may have a non-magnetic surface on the opposite side. Magnetic powder (carbon black, inorganic powder, abrasive,
A back layer containing a solid or liquid lubricant) and a binder may be provided. Further, in the long magnetic recording medium of the present invention, in addition to the lubricant in the magnetic layer or the back layer, a rust preventive, a mildew proofing agent, an antistatic agent, a non-magnetic powder, a dye, an organic magnetic compound, a dispersant. A mixed layer composed of different or the same magnetic fine particles of ferromagnetic fine powder,
It may have a multi-layered structure.

That is, the present invention provides a long magnetic recording medium in which a magnetic layer containing a ferromagnetic fine powder and a binder is provided on a non-magnetic support, and the magnetic properties at the beginning and the end per 100 m of the long magnetic recording medium. By setting the layer gloss difference to less than 0.1% and the Ra difference to less than 0.02 nm, a long magnetic recording medium having high output and high density recording and extremely excellent running durability in the tape longitudinal direction was obtained. It is a thing. Further, in the present invention, by achieving these, the quality difference in the longitudinal direction of the long magnetic recording medium is eliminated, there is little variation between lots, and the long magnetic recording medium is extremely excellent in running durability such as wear characteristics and friction characteristics. A magnetic recording medium is obtained. 1000m for efficient production of long magnetic recording media
The above-mentioned non-magnetic support was coated, oriented and dried on the magnetic layer and / or the back layer, and then calendered continuously or discontinuously. 1000m of these
In the coated product described above, when the coated product is wound up, a difference in the physical properties of the magnetic layer and / or the back layer occurs at the winding start end and the winding end. In particular, when heat treatment is applied to these coating materials at a temperature of 40 ° C. or higher to remove thermal strain of the coating materials, the coating materials are tightly wound and a very large tightening pressure is applied to the coating material on the core side. . Therefore, in the magnetic layer or back layer of the heat-treated coating, the core side portion becomes smoother than the outer side portion, and the glossiness increases. The thus smoothed magnetic layer or back layer in the core side portion is likely to have an increased friction coefficient, and is likely to cause a sticking phenomenon with the cylinder, head, and guide of the VTR. Further, the smoothing reduces the protrusions on the surface of the magnetic layer, which deteriorates the wear property, and the eyes of the VTR head are clogged, and the running system of the VTR is easily soiled. For this reason, a sufficient amount of liquid to ensure a friction coefficient on the core side of the heat treated coating
Although it is possible to secure running characteristics in the core side portion by adding a solid lubricant or inorganic powder (carbon etc.), in the outer portion of the coated material, the filling degree and glossiness decrease, It causes an unexpectedly rough surface, and it becomes extremely difficult to make the wear properties of the core side and the outside of the magnetic layer uniform. The present invention specifically addresses these problems in a long magnetic recording medium in which a magnetic layer containing a ferromagnetic fine powder and a binder is provided on a non-magnetic support.
Less than 1% difference in glossiness at the beginning and end per unit of 00 m, R
The measure can be taken by a method of manufacturing a long magnetic recording medium in which the difference a is less than 0.2 nm.

In particular, in the present invention, when one roll is subjected to calendering in the manufacturing process of a long magnetic recording medium, the calender pressure is temporarily increased or the calender temperature is temporarily increased from the start to the end so that the coating material core side is increased. The smoothing of the magnetic layer can be made uniform toward the end.

Such a long magnetic recording medium of the present invention can be specifically obtained by the following two methods. That is, one is to provide a magnetic layer containing ferromagnetic fine powder and a binder on a non-magnetic support, carry out calendering treatment, and then heat the obtained long magnetic recording medium at 40 ° C. or more for 4 hours or more. In the method for producing a long magnetic recording medium to be carried out, in the calendering process, the calender pressure is temporarily increased from the head to the tail of one roll, and preferably the calender pressure is 200 kg / cm at the head of the one roll. Set to ~ 350 kg / cm, raise for a while, and set the calender pressure to 220 at the end.
The pressure difference is 20 kg / cm to 400 kg / cm.
It is to be set to kg / cm to 200 kg / cm.

Another method is to provide a magnetic layer containing a ferromagnetic fine powder and a binder on a non-magnetic support, carry out calendering, and then obtain the obtained long magnetic recording medium at 40 ° C. or higher for 4 hours or longer. In the method for producing a long magnetic recording medium in which heat treatment is performed, in the calendering process, the calender temperature is raised for a while from the beginning to the end of one roll, and preferably the calender temperature is set to 50 at the beginning of the one roll. C. to 100.degree. C. is set, the temperature is raised for a while, the calender temperature is set to 60.degree. C. to 110.degree. C. at the end, and the temperature difference is 5.degree. C. to 40.degree. As described above, according to the present invention, the long magnetic recording medium is kept at 40 ° C.
When the heat treatment is performed for 4 hours or more, the magnetic layer on the roll core side after calendering has a rougher surface and lower gloss than the magnetic layer on the outside. By substantially eliminating the difference between the surface property and the glossiness, the surface property of the magnetic layer can be made uniform from the core side of the post-slit product toward the end direction.

Even when the coated article is rolled up, the magnetic properties of the magnetic layer at the leading end and the trailing end of the coating differ due to the phenomenon of winding tightness, so that the surface properties of the magnetic layer or the back layer may be different from each other at the stage of carrying out the present invention. Is. For tightening the coated material, 1000m to 2000m, 2000m
From 4000m, from 4000m to 8000m, 8000
It is more likely to occur at 16000 m than m. Therefore, the present invention is very effective for efficient and uniform production. In addition, the winding tension may be devised to eliminate the difference between the starting end and the ending end of these coating materials, but the effect is not clear. Further, the means of the present invention can be carried out at any stage as long as it is a process after coating the magnetic layer in the manufacturing process.

The calender condition in the present invention is preferably a multi-stage calender having two or more stages. As the calendar, any one such as a metal roll or a plastic roll can be used. The calendar temperature is 40 to 90 at the beginning of the calendar.
It is desirable that the end of the calender is 50 to 100 ° C. It can also be controlled by calender roll pressure.
Roll pressure is linear pressure, the initial calendar is 200-350
Kg / cm, end of calendar 220-400 Kg / c
It is desirable that it is m. It can also be controlled by the web transfer speed of the calendar. The web transfer speed on the calendar is 100 to 500 m / mi at the beginning of the calendar.
n, and the end of the calendar is preferably 50 to 450 Kg / cm. Under any of the conditions, it is necessary that the calender initial condition, that is, the core side of the roll to be heat-treated is conditionally weaker than the outside of the roll. For example, when controlling the temperature, the calendar is started at 80 ° C and the end is controlled at 90 ° C. In the case of controlling with pressure, for example, the calender is started at a linear pressure of 250 Kg / cm, and the end is controlled at 300 Kg / cm.
For example, if you want to control the speed, start the calendar by 2
It is performed at 00 m / min, and is controlled at 150 m / min at the terminal end. When controlling with the number of calendar steps, start the calendar with 7 steps and set 6, 5,
4. At the end, it can be controlled like three steps. Specific methods other than these examples are possible.

Regarding the calendar device and the like, Japanese Patent Laid-Open No. 51-
92606, JP-A-51-103404, JP-A-52-150605, JP-A-58-194142 and the like can be used. The calender pressure can be changed by manually or automatically adjusting the gauge. The temperature can be adjusted by using an induction heating roll and setting the temperature of the roll.

The surface roughness (Ra) of the magnetic layer of the present invention is measured by a stylus surface roughness meter (Tokyo Seimitsu K, Surfcom 800A manufactured by K).
Type). The cutoff value at this time is 0.08
mm. It can be measured according to JIS-B0601. The glossiness of the magnetic layer surface of the present invention is JI
According to S-Z8741, the specular glossiness of the black glass surface having a refractive index of 1.567 was measured at an incident angle of 45 degrees as 100%.

The ferromagnetic fine powder of the present invention includes γ-Fe
₂ O ₃ , Co-containing (deposition, metamorphism, doping) γ-Fe ₂ O
F containing ₃ , Fe ₃ O ₄ , and Co (deposition, metamorphism, doping)
e ₃ O ₄ , γ-FeOx, Co content (deposition, metamorphism, doping
Γ-FeOx (X = 1.33 to 1.5)
0), CrO _2, etc. can also be used, but especially α-Fe, C
o, Ni, Fe-Co alloy, Fe-Co-Ni alloy, F
e-Co-Ni-P alloy, Fe-Co-Ni-B alloy,
Fe-Ni-Zn alloy, Ni-Co alloy, Co-Ni-
Ferromagnetic metal fine powders such as Fe alloys are preferred. The particle size of these ferromagnetic metal fine powders is about 0.005 to 1 micron, and the ratio of axial length / axial width is about 1/2 to 15/1. Moreover, the specific surface area of these ferromagnetic metal fine powders is 4
7 to 80 m ² / g, more preferably 53 to 70 m ² / g,
Coercive force (Hc) is 1250 to 2500 Oe, water content is 0.1 to 2.0% by weight, PH is 3 to 11 (5 g magnetic material /
100 g water) is preferred. The surface of these ferromagnetic fine powders may be impregnated with a rust preventive agent, a surface treatment agent, a dispersant, a lubricant, an antistatic agent, etc. in a solvent prior to dispersion for each purpose and may be adsorbed. . The long magnetic recording medium of the present invention has a magnetic layer in which these ferromagnetic fine powders are dispersed in a binder provided on a non-magnetic support. Further, the metal content in the ferromagnetic alloy powder is 60 wt% or more, and 70 wt% or more of the metal content is at least one ferromagnetic metal or alloy (eg, Fe, Fe-Co, Fe-Co-Ni,
Co, Ni, Fe-Ni, Co-Ni, Co-Ni-F
e) and other components (eg Al, S) within the range of 40% by weight or less, more preferably 20% by weight or less of the metal content.
i, S, Sc, Ti, V, Cr, Mn, Cu, Zn,
Y, Mo, Rh, Pd, Ag, Sn, Sb, Te, B
a, Ta, W, Re, Au, Hg, Pb, Bi, La,
Ce, Pr, Nd, B, P) which may contain alloys,
Examples thereof include iron nitride and iron carbide. In particular, in order to supplement the strength of metallic iron among them, it is preferable to provide Al, Si, and Cr individually or in a mixture on the surface layer. In addition, the above-mentioned ferromagnetic metals are small amounts of hydroxides or oxides, alkali metal elements (Na, K, etc.), alkaline earth metal elements (M
g, Ca, Sr) or the like. The method for producing these ferromagnetic metal powders is already known, and the ferromagnetic alloy powder, which is a typical example of the ferromagnetic powder used in the present invention, can also be produced according to these known methods.

That is, the following method can be given as an example of the method for producing the ferromagnetic alloy fine powder. (A) A method of reducing a complex organic acid salt (mainly oxalate) with a reducing gas such as hydrogen, and (b) reducing iron oxide with a reducing gas such as hydrogen to obtain Fe or Fe-Co particles. A method, (c) a method of thermally decomposing a metal carbonyl compound, (d) a method of adding a reducing agent such as sodium borohydride, hypophosphite or hydrazine to an aqueous solution of a ferromagnetic metal for reduction, (e) A method of electrolyzing ferromagnetic metal powder using a mercury cathode and then separating it from mercury,
(F) a method of evaporating a metal in a low pressure inert gas to obtain a fine powder,

When the ferromagnetic metal fine powder is used, its shape is not particularly limited, but normally, needle-like, granular, dice-like, rice granular and plate-like ones are used. Ratios are preferred. Further, σs of these ferromagnetic materials is preferably 100 to 210 emu / g. The crystallite size is preferably 100 to 300A. The dice-shaped one is preferably cubic or hexahedral or octahedral. For the plate-shaped one, the plate-shaped / thickness ratio is
It is preferably 3/1 to 30/1. Examples of these ferromagnetic alloy fine powders are JP-A-53-70397, JP-A-58-119609, and JP-A-58-130435.
JP-A-59-80901, JP-A-59-1690
3, JP-A-59-41453, JP-B-61-377.
61, U.S. Pat. No. 4,447,264, U.S. Pat.
No. 021 and US Pat. No. 4,931,198.

As the binder used in the magnetic layer or back layer of the present invention, conventionally known thermoplastic resins, thermosetting resins, reactive resins, electron beam curable resins, ultraviolet curable resins, visible light curable resins are used. Resins and mixtures of these are used. As a thermoplastic resin, the softening temperature is 150 ° C or lower,
Average molecular weight 10,000 to 300,000, degree of polymerization about 5
About 0 to 2000, more preferably 200 to 60
0, for example vinyl chloride vinyl acetate copolymer,
Vinyl chloride copolymer, vinyl chloride vinyl acetate vinyl alcohol copolymer, vinyl chloride vinyl alcohol copolymer, vinyl chloride vinylidene chloride copolymer, vinyl chloride acrylonitrile copolymer, acrylic ester acrylonitrile copolymer, acrylic ester Vinylidene chloride copolymer, acrylic ester styrene copolymer, methacrylic acid ester acrylonitrile copolymer, methacrylic acid ester vinylidene chloride copolymer, methacrylic acid ester styrene copolymer, urethane elastomer, nylon-silicone resin, nitrocellulose -Su-polyamide resin, poly (vinyl fluoride), vinylidene chloride acrylonitrile copolymer, butadiene acrylonitrile copolymer,
Polyamide resin, polyvinyl butyral, cellulose derivative (cellulose acetate butyrate, cellulose diacetate, cellulose triacetate, cellulose propionate, nitrocellulose, ethyl cellulose)
, Methyl cellulose, propyl cellulose, methyl ethyl cellulose, carboxymethyl cellulose, acetyl cellulose, etc.), styrene butadiene copolymer, polyester resin, polycarbonate resin, chlorovinyl ether acrylate copolymer Combined materials, amino resins, various synthetic rubber thermoplastic resins, and mixtures thereof are used. Examples of these resins include Japanese Patent Publication No. 37-6877.
Issue, Japanese Examined Patent Publication No. 39-12528, Japanese Examined Patent Publication No. 39-1928
No. 2, JP-B-40-5349 JP-B-40-2090
No. 7, Japanese Patent Publication No. 41-9463, Japanese Patent Publication No. 41-1405
No. 9, Japanese Patent Publication No. 41-16985 Japanese Patent Publication No. 42-642
No. 8, Japanese Patent Publication No. 42-11621, Japanese Patent Publication No. 43-462
No. 3, JP-B-43-15206, JP-B-44-288
No. 9, JP-B-44-17947, JP-B-44-182
No. 32, Japanese Patent Publication No. 45-14020, Japanese Patent Publication No. 45-14
No. 500, Japanese Patent Publication No. 47-18573, Japanese Patent Publication No. 47-2
2063, Japanese Patent Publication No. 47-22064 Japanese Patent Publication No. 47-
22068, Japanese Patent Publication No. 47-22069, Japanese Patent Publication No. 47
-22070, Japanese Patent Publication No. 47-27886, Japanese Patent Laid-Open No.
57-133521, JP-A-58-137133, JP-A-58-166533, JP-A-58-222433, JP-A-59-58642, etc., US Pat. No. 4,571,364,
It is described in US Pat. No. 4,752,530.

Application as a thermosetting resin or reactive resin
In the liquid state, the molecular weight is 200,000 or less.
Reactions such as condensation and addition by heating and humidifying after drying
Makes the molecular weight infinite. Also, these resins
Among them, the resin softens or melts before it thermally decomposes.
Those that do not exist are preferred. Specifically, for example, a phenol tree
Fat, phenoxy resin, epoxy resin, polyurethane resin
Fat, polyester resin, polyurethane polycarbonate
Resin, urea resin, melamine resin, alkyd resin, sili
Con resin, acrylic reaction resin (electron beam curing resin), d
Poxy-polyamide resin, nitrocellulose-smelamine resin
Fat, high molecular weight polyester resin and isocyanate prepo
Mixers of limers, methacrylate copolymers and diisocyanates
Mixture of net prepolymer, polyester polyol
Of urea and polyisocyanate, urea formaldehyde
Resin, low molecular weight glycol / high molecular weight diol / tri
A mixture of phenylmethane triisocyanate, polyamid
Resin, polyimine resin and mixtures thereof.
Examples of these resins include Japanese Patent Publication No. 39-8103 and Japanese Patent Publication No.
40-9779, Japanese Patent Publication No. 41-7192, Japanese Patent Publication No. 4
1-8016 Japanese Patent Publication No. 41-14275, Japanese Patent Publication No. 4
2-18179, Japanese Patent Publication No. 43-12081, Japanese Patent Publication No.
No. 44-28023 Japanese Patent Publication No. 45-14501, Japanese Patent Publication
45-24902, JP-B-46-13103, special
JP-B-47-22065, JP-B-47-22066,
Japanese Patent Publication No. 47-22067, Japanese Patent Publication No. 47-22072
No. 47-20743
No. 5, Japanese Patent Publication No. 47-28048, Japanese Patent Publication No. 47-289
22 and other publications. These thermoplastics, heat
Curable resin and reactive resin are the main functionalities of resin
Carboxylic acid (COOM), sulf
Phosphoric acid, sulfenic acid, sulfonic acid (SO₃M), phosphoric acid
(PO (OM) (OM)), phosphonic acid, sulfuric acid (OSO)
₃M) and acidic groups such as ester groups (M is H,
Alkali metals, alkaline earth metals, hydrocarbon groups),
Acids; aminosulfonic acids, sulfuric acid of amino alcohol
Or amphoteric compounds such as phosphoric acid esters and alkyl betaines
Groups, amino groups, imino groups, imide groups, amide groups, etc.
Hydroxyl group, alkoxyl group, thiol group, alkylthio
Groups, halogen groups (F, Cl, Br, I), silyl groups,
Roxane group, epoxy group, isocyanato group, cyano group,
Nitrile group, oxo group, acrylic group, phosphine group
Normally, 1 to 6 types are included, and each functional group is 1 g of resin.
1 x 10^-6eq ~ 1 x 10 ^-2It is preferable to include eq
Yes. Among the resins, especially sulfonic acid, phosphoric acid, phosphon
At least one or more functional groups of acid, epoxy group, and hydroxyl group
Resins having are preferred.

The polyisocyanate used in the magnetic layer or back layer of the present invention includes tolylene diisocyanate,
4,4'-diphenylmethane diisocyanate, hexamethylene diisocyanate, xylylene diisocyanate
, Naphthylene-1,5-diisocyanate, o-toluidine diisocyanate, isophorone diisocyanate
, Triphenylmethane triisocyanate, isophorone diisocyanate, and other isocyanates, the products of the isocyanates with polyalcohol, and the condensation of the isocyanates. It is possible to use the above-mentioned 2- to 10-mer polyisocyanate, or the product of a polyisocyanate and polyurethane in which the terminal functional group is isocyanate. The average molecular weight of these polyisocyanates is preferably 100 to 20,000.
Commercially available trade names of these polyisocyanates are Coronet L, Coronet HL, and Coronet 20.
30, Coronet 2031, Millionate MR, Millionate MTL (Nippon Polyurethane Co., Ltd.), Takenet D
-102, Takenet D-110N, Takenet D-
200, Takenet D-202, Takenet 300S,
Takenet 500 (manufactured by Takeda Pharmaceutical Co., Ltd.), Sumire T-
80, Sumidule 44S, Sumidule PF, Sumidule L, Sumidule N, Desmodule L, Desmodule IL, Desmodule N, Desmodule H
L, Death module T65, Death module 15, Death module R, Death module RF, Death module S
L, Desmodule Z4273 (manufactured by Sumitomo Bayer Co., Ltd.) and the like, and these can be used alone or in combination of two or more utilizing the difference in curing reactivity. In addition, for the purpose of accelerating the curing reaction, hydroxyl groups (butanediol, hexanediol, molecular weight 100
It is also possible to use a compound having an amino group (monomethylamine, dimethylamine, trimethylamine, etc.), a metal oxide catalyst, or a catalyst such as iron acetylacetonate, together with 0-10000 polyurethane, water, etc.). It is desirable that these compounds having a hydroxyl group or an amino group are polyfunctional. These polyisocyanates are preferably used in both the magnetic layer and the back layer in an amount of 2 to 70 parts by weight, and more preferably 5 to 50 parts by weight, per 100 parts by weight of the total amount of the binder resin and the polyisocyanate. Examples of these are shown in JP-A-60-131622 and JP-A-61-74138.

These binders may be used alone or in combination, and other additives may be added. The mixing ratio of the ferromagnetic fine powder and the binder in the magnetic layer is 3 to 100 parts by weight of the binder with respect to 100 parts by weight of the ferromagnetic fine powder. The mixing ratio of the fine powder and the binder in the back layer is 8 to 150 parts by weight based on 100 parts by weight of the fine powder.
Used in the range of parts by weight. Additives include dispersants, lubricants, abrasives, antistatic agents, antioxidants, solvents and the like. The carbon black used in the magnetic layer and / or the back layer of the present invention may be a furnace for rubber, thermal for rubber, black for color, acetylene black or the like. These carbon blacks are used as an antistatic agent, a light-shielding agent, a friction coefficient adjusting agent, and a durability improving tape. Specific examples of these carbon black abbreviations in the US are SAF, ISAF, I.
ISAF, T, HAF, SPF, FF, FEF, HM
F, GPF, APF, SRF, MPF, ECF, SC
F, CF, FT, MT, HCC, HCF, MCF, LF
F, RCF, etc., American ASTM standard D-176
Those classified as 5-82a can be used. The carbon black used in the present invention has an average particle size of 5 to 1000 millimicrons (electron microscope), a nitrogen adsorption method specific surface area of 1 to 800 m ² / g, and a PH.
Is 4 to 11 (JIS standard K-6221-1982 method),
Dibutyl phthalate (DBP) oil absorption is 10-800m
1 / 100g (JIS standard K-6221-1982 method)
Is. The size of the carbon black used in the present invention is 5-100 for the purpose of lowering the surface electric resistance of the coating film.
Millimicron carbon black is used, and 50 to 1000 millimicron carbon black is used to control the strength of the coating film. Further, for the purpose of controlling the surface roughness of the coating film, fine carbon black (less than 100 mm) is used for smoothing the surface, and for the purpose of roughening the carbon black to reduce the friction coefficient. (100
Mm or more) is used. As described above, the kind and the amount of the carbon black added are properly selected according to the purpose required for the long magnetic recording medium. Further, these carbon blacks may be used after being surface-treated with a dispersant described later or grafted with a resin. Further, it is also possible to use one in which part of the surface is graphitized by treating the temperature of the furnace at the time of producing carbon black at 2000 ° C. or higher.
Hollow carbon black can also be used as a special carbon black. In the case of the magnetic layer, it is desirable to use 0.1 to 20 parts by weight with respect to 100 parts of the ferromagnetic fine powder. In the case of the back layer, it is desirable to use 20 to 400 parts by weight with respect to 100 parts by weight of the binder. The carbon black that can be used for the back layer can be referred to, for example, "Carbon Black Handbook", edited by Carbon Black Association (published in 1972). Examples of these carbon blacks are US Pat. No. 4,539,257 and US Pat. No. 461.
4685, JP-A-61-92424, JP-A-61-
It is described in Japanese Patent Publication No. 99927.

The abrasive used in the magnetic layer or the back layer of the present invention is used to improve the durability of the long magnetic tape, and is generally a material having an abrasive action or a polishing action, and is α-alumina or γ. -Alumina, α, γ-alumina It is preferable to use at least one of fused alumina, chromium oxide, and diamond. Other abrasives such as silicon carbide, cerium oxide, corundum,
α-iron oxide, garnet, emery (main component: corundum and magnetite), garnet, silica, silicon nitride, boron nitride,
Molybdenum carbide, boron carbide, tungsten carbide, titanium carbide, tripoly, diatomaceous earth, dolomite, etc.
It is preferable to mainly use materials having a Mohs hardness of 6 or more in a combination of 1 to 4 kinds. As these abrasives, those having an average particle size of 0.005 to 5 μm are used, and particularly preferably 0.01 to 2 μm. These abrasives are preferably used in an amount of 0.1 to 20 parts by weight with respect to 100 parts by weight of the ferromagnetic fine powder in the magnetic layer. Further, these abrasives are used for the non-magnetic powder 100 of the back layer.
It is desirable to use 0.01 to 5 parts by weight with respect to parts by weight. Specific examples of these are AK manufactured by Sumitomo Chemical Co., Ltd.
P1, AKP15, AKP20, AKP30, AKP5
0, AKP80, Hit50, Hit100 and the like. Regarding these, Japanese Patent Publication No. 52-28642, Japanese Patent Publication No. 49-39402, and Japanese Patent Publication No. 63-98828,
US Patent 3687725, US Patent 3007807
U.S. Pat. No. 3,041,196, U.S. Pat.
6, U.S. Pat. No. 3,630,910, U.S. Pat. No. 38334.
12, US Patent 4,117,190, British Patent 1145.
No. 349, West German Patent No. 853211, and the like.

The powdery lubricant used in the magnetic layer and / or back layer of the present invention includes graphite, molybdenum disulfide, boron nitride, graphite fluoride, calcium carbonate,
Inorganic fine powder such as barium sulfate, silicon oxide, titanium oxide, zinc oxide, tin oxide, tungsten disulfide, acrylic styrene resin fine powder, benzoguanamine resin fine powder, melamine resin fine powder, polyolefin resin fine powder, polyester Resin fine powder, polyamide resin fine powder, polyimide resin fine powder, resin fine powder such as polyfuccoethylene ethylene resin fine powder, and the like. As the organic compound-based lubricant, silicon oil (dialkyl polysiloxane, dialkoxy polysiloxane, phenyl polysiloxane,
Fluoroalkyl polysiloxane (KF9 manufactured by Shin-Etsu Chemical)
6, KF69, etc.)), fatty acid-modified silicone oil, fluorine alcohol, alkane (liquid paraffin), polyolefin (polyethylene wax, polypropylene, etc.),
Polyglycol (ethylene glycol, polyethylene oxide wax, etc.), tetrafluoroethylene oxide wax, polytetrafluoroglycol, perfluoroalkyl ether, perfluoro fatty acid, perfluoro fatty acid ester, perfluoroalkyl sulfate ester, per Fluoroalkylsulfonic acid ester, perfluoroalkylbenzenesulfonic acid ester, perfluoroalkylphosphoric acid ester (for example, Krytox, etc.) containing fluorine or silicon, alkyl sulfuric acid ester, alkylsulfonic acid ester, alkylphosphonic acid triester , Alkylphosphonic acid monoester,
Organic acids and organic acid ester compounds such as alkylphosphonic acid diesters, alkylphosphoric acid esters, and succinic acid esters, nitrogen-sulfur-containing complexes such as triazaindolizine, tetraazaindene, benzotriazole, benzotriazine, benzodiazole, and EDTA (Hetero) ring compound, monobasic fatty acid having 10 to 40 carbon atoms and 2 to 2 carbon atoms
40 monovalent or divalent alcohols,
Trivalent alcohol, tetravalent alcohol, hexavalent alcohol
Fatty acid ester consisting of any one or two or more of the above, monobasic fatty acids having 10 or more carbon atoms, and monovalent to six carbon atoms having a total of 11 to 70 carbon atoms. It is also possible to use fatty acid esters consisting of valence alcohols, fatty acids having 8 to 40 carbon atoms or fatty acid amides, fatty acid alkylamides, and aliphatic alcohols. These carbons may be branched at any place. The location of branching is preferably iso or 2- or 3-position branching. Octyl caprylate, ethyl laurate, butyl laurate, octyl laurate, ethyl myristate, butyl myristate, octyl myristate, 2-ethylhexyl myristate, ethyl palmitate, butyl palmitate, octyl palmitate, 2-ethylhexyl palmitate,
Ethyl stearate, butyl stearate, isobutyl stearate, octyl stearate, stearic acid 2
Ethylhexyl, amyl stearate, isoamyl stearate, 2-ethylpentyl stearate, 2-hexyldecyl stearate, isotridecyl stearate, stearic acid amide, stearic acid alkylamide, butoxyethyl stearate, anhydrosorbitan monostearate, an Hydrosorbitan distearate, anhydrosorbitan tristearate, anhydrosorbitan tetrastearate, oleyl oleate, oleyl alcohol, lauryl alcohol, montan wax, carnauba wax, etc. alone or Can be used in combination. As the lubricant used in the present invention, so-called lubricating oil additives can be used alone or in combination, and antioxidants (alkylphenol, benzotriazine, tetraazaindene, sulfamide) which are known as rust preventives are used. , Metal chelators such as guanidine, nucleic acid, pyridine, amine, hydroquinone, and EDTA), rust suppressant (naphthenic acid, alkenyl succinic acid, phosphoric acid, dilauryl phosphate, etc.), oiliness agent (rapeseed oil, lauryl alcohol) , Etc.), extreme pressure agents (dibenzyl sulfide, tricresyl phosphate, tributyl phosphite, etc.),
Detergent dispersants, viscosity index improvers, pour point depressants, foam depressants, etc. These lubricants may be used in the form of a composite, or one having two or more of these characteristic groups introduced into one molecule.

Examples include fluorine group-introduced fatty acid, fluorine group-introduced fatty acid ester, siloxane-introduced fatty acid, siloxane-introduced fatty acid ester, and the like. These lubricants are added in the range of 0.01 to 30 parts by weight with respect to 100 parts by weight of the binder of the magnetic layer and / or the back layer. About these, Japanese Patent Publication No. 43-23889 and Japanese Patent Publication No. 48-24
041, Japanese Patent Publication No. 48-18482, Japanese Patent Publication No. 44-1
8221, Japanese Patent Publication No. 47-28043, Japanese Patent Publication No. 57-5
6132, JP-A-59-8136, JP-A-59-81
39, JP-A-61-85621, U.S. Pat. No. 3,423.
233, US Pat. No. 3470021, US Pat.
2235, US Pat. No. 3,497,411, US Patent 35
23086, US Patent 3,625,760, US Patent 3
630772, U.S. Pat. No. 3,634,253, U.S. Pat. No. 3,642,539, U.S. Pat. No. 3,687,725, U.S. Pat. No. 4135031, U.S. Pat. No. 4,497,864, U.S. Pat. No. 4,552,794, IBM Technical Day.
Sukuroja Britain (IBM Technical)
Disclosure Bulletin) Vol.
9, No7, p779 (December 1966), Electronic (ELEKTRONIK) 1961 No12,
p380, Handbook of Chemistry, Advanced Edition, p954-967, 19
It is described in the issue of Maruzen Co., Ltd. in 1980.

Examples of the dispersant and dispersion aid used in the present invention include caprylic acid, capric acid, lauric acid, myristic acid, palmitic acid, stearic acid, oleic acid, elaidic acid, linoleic acid, linolenic acid, stearoic acid. -Fatty acids such as acid, behenic acid, maleic acid, phthalic acid, etc., having 2 to 40 carbon atoms (R1 COOH, R1 is alkyl group having 1 to 39 carbon atoms, phenyl group, aralkyl group), alkali of the above fatty acids Metal soaps (copper oleate) composed of metals (Li, Na, K, NH4 + etc.) or alkaline earth metals (Mg, Ca, Ba etc.), Cu, Pb etc., fatty acid amides; lecithin (soy oil lecithin) etc. Is used. In addition to these, higher alcohols having 4 to 40 carbon atoms (butanol, octyl alcohol, myristyl alcohol, stearyl alcohol, cetyl alcohol, isocetyl alcohol) and their sulfates, sulfonic acids, Phenyl sulfonic acid, alkyl sulfonic acid, sulfonic acid ester, phosphoric acid monoester, phosphoric acid diester, phosphoric acid triester, alkylphosphonic acid, phenylphosphonic acid, amine compound and the like can also be used. Also, polyethylene glycol,
Polyethylene oxide, sulfosuccinic acid, sulfosuccinic acid metal salt, sulfosuccinic acid ester and the like can also be used. These dispersants are usually used in one or more kinds, and one kind of the dispersant is added in the range of 0.005 to 20 parts by weight with respect to 100 parts by weight of the binder. The usage of these dispersants is
It may be deposited on the surface of the ferromagnetic fine powder or the non-magnetic fine powder in advance, or may be added during the dispersion. Such a material is disclosed, for example, in Japanese Patent Publication No. 39-28369 and Japanese Patent Publication No. 44-1.
7945, Japanese Patent Publication No. 44-18221, Japanese Patent Publication No. 48-
7441, Japanese Patent Publication 48-15001, Japanese Patent Publication 48-
15002, Japanese Patent Publication No. 48-16363, Japanese Patent Publication No. 49
-39402, U.S. Pat. Nos. 3,387,993 and 347.
No. 0021 and the like.

The antifungal agent used in the present invention is 2- (4-
Thiazolyl) -benzimidazole, N- (fluorodichloromethylthio) -phthalimide, 10,10'-oxybisphenoxarcin, 2,4,5,6 tetrachloroisophthalonitrile, P-tolyldiiodomethylsulfone, triiodo Examples include allyl alcohol, dihydroacetate, mercury phenyloleate, bis (tributyltin) oxide, and saltylanilide. Such a thing is shown, for example, in "Microbial Hazard and Prevention Technology", 1972 Engineering Book, "Chemistry and Industry" 32,904 (1979), and the like. These antifungal agents are used in the range of 0.005 to 20 parts by weight based on 100 parts by weight of the binder.

Antistatic agents other than carbon black used in the present invention include graphite, modified graphite, carbon black graft polymer, tin oxide-antimony oxide, tin oxide, titanium oxide-tin oxide-antimony oxide,
Conductive powders such as saponin; Natural surfactants such as saponin; Nonionic surface active agents such as alkylene oxide type, glycerin type, glycidyl type, polyhydric alcohol, polyhydric alcohol ester, and alkylphenol EO adduct Agents; higher alkyl amines, cyclic amines, hydantoin derivatives, amido amines, ester amides, quaternary ammonium salts, pyridine and other heterocycles, cationic surfactants such as phosphonium or sulfoniums; carboxylic acids, sulfonic acids, phosphonic acids , Anionic surfactants containing acidic groups such as phosphoric acid, sulfuric acid ester groups, phosphonic acid ester groups, phosphoric acid ester groups, etc .; amino acids; aminosulfonic acids, sulfuric acid or phosphoric acid esters of amino alcohols, amphoteric interfaces such as alkyl betaine type Activators and the like are used. Some examples of surfactant compounds that can be used as these antistatic agents are disclosed in JP-A-60-28025 and US Pat.
No. 2, No. 2240472, No. 2288226, No. 26
No. 76122, No. 2676924, No. 2676975
Nos. 2,691,566, 2727860, 27
No. 30498, No. 2742379, No. 2739891
No. 3068101, No. 3158484, No. 32
No. 01253, No. 3210191, No. 3294540
No. 3415649, No. 3441413, No. 34
42654, 3475174, and 3545974.
, West German Patent Publication (OLS) 1942665, British Patents 1077317, 1198450, etc.,
Ryohei Oda et al., “Synthesis of surfactants and their applications” (Maki Shoten 1972 edition); W. Bailey's "Surface Active Agents" (Interscience Publications Coporated 1985 edition);
P. Sisley's "Encyclopedia of Surfactive Agents, Volume 2" (Chemical Publishing Company, 1964 edition); "Surfactant Handbook", 6th edition (Sangyo Tosho Co., Ltd., 1241) 20 a month
Sun); Hideo Marumoshi, "Antistatic Agent," written in Koshobo (1968). These surfactants may be added alone or as a mixture. The amount of these surfactants used in the long magnetic recording medium is 0.01 to 10 parts by weight per 100 parts by weight of the ferromagnetic fine powder. The amount used in the back layer is 0.0 per 100 parts by weight of the binder.
It is 1 to 30 parts by weight. These are used as antistatic agents, but sometimes for other purposes, such as dispersion, improvement of long magnetic properties, improvement of lubricity, coating aids, wetting agents, curing accelerators, dispersion accelerators. It may be applied.

As the organic solvent used in the dispersion, kneading and coating of the present invention, ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, isophorone and tetrahydrofuran in arbitrary ratios; methanol, ethanol , Propanol, butanol, isobutyl alcohol, isopropyl alcohol, methylcyclohexanol, and other alcohols; methyl acetate,
Ester systems such as ethyl acetate, butyl acetate, isobutyl acetate, isopropyl acetate, ethyl lactate, glycol acetate monoethyl ether; ethers such as diethyl ether, tetrahydrofuran, glycol dimethyl ether, glycol monoethyl ether, dioxane System: benzene, toluene, xylene, cresol, chlorobenzene, styrene and other tar systems (aromatic hydrocarbons); methylene chloride, ethylene chloride, carbon tetrachloride, chloroform, ethylene chlorohydrin, dichlorobenzene, etc. Chlorinated hydrocarbons, N, N-dimethylformaldehyde, hexane and the like can be used. Further, these solvents are usually used in two or more kinds at an arbitrary ratio. In addition, a trace amount of impurities (polymer of the solvent itself, water,
Raw material components, etc.) may be included. These solvents are used in an amount of 100 to 200,000 parts by weight based on 100 parts by weight of the total solid content of the magnetic liquid, the back liquid and the undercoat liquid. The solid content of the magnetic liquid is preferably 5 to 40% by weight. The solid content of the backing liquid is preferably 5 to 30% by weight. An aqueous solvent (water, alcohol, acetone, etc.) can be used instead of the organic solvent.

The magnetic recording layer and the back layer are formed by arbitrarily combining the above-mentioned compositions and the like or individually or in combination with an organic solvent, and impregnating, dissolving, mixing, dispersing, kneading, and diluting them in any order to form a coating solution. Create and apply / dry /
Orient. When used as a tape or disk, the thickness of the support is preferably about 2.5 to 500 μm, more preferably about 3 to 100 μm. As materials, polyethylene naphthalate, polyethylene terephthalate,
Plastics such as polyimide and polyamide are preferred.
Regarding these supports, for example, West German Patent 333885
4A, JP-A-59-116926, JP-A-61-12
9731, U.S. Pat. No. 4,388,368; Yukio Mitsuishi,
"Fiber and Industry", Vol. 31, p50-55, 1975. In the case of a video tape or the like, the center line average surface roughness of these supports is 0.1 to 30 nanometers (n
m) (cutoff value 0.25 mm) is preferred. The Young's modulus (F5 value) of these supports can be selected from 2 to 100 kg / mm @ 2 in both the width direction and the longitudinal direction depending on the purpose. Is.

The method of dispersion and kneading is not particularly limited, and the order of addition of each component (resin, powder, lubricant, solvent, etc.),
The addition position during dispersion / kneading, the divided addition of the same raw material, the dispersion temperature (0 to 80 ° C.), the humidity and the like can be appropriately set. For preparing magnetic paints and back layer paints, conventional kneading machines such as a two-roll mill, a three-roll mill, a ball mill, a pebble mill, a tron mill, a sand grinder,
Szegvari Attritor, High Speed Impeller, Disperser, High Speed Stone Mill, High Speed Impact Mill, Disperser, Kneader, High Speed Mixer, Ribbon Blender, Conveyor, Intensive Mixer, Tumbler, blender, disperser, homogenizer, single-screw extruder, twin-screw extruder,
Also, an ultrasonic disperser or the like can be used. Usually, a plurality of these dispersing / kneading machines are provided for the dispersing / kneading, and the treatment is continuously performed. For details of the technique regarding kneading and dispersion, see T.W. C.
PATTON (T-C-Patton) "Paint
Flow and Pigment Dispersers
Ion ”(Paint Flow and Pigment Day Spar John) 1964 John Wiley &
Published by Sons (John Willy and Sons) and Shinichi Tanaka, "Industrial Materials," Vol. 25, 37 (197).
7) etc. and the references cited in the book. As an auxiliary material for the dispersion and kneading, in order to efficiently carry out the dispersion and kneading, steel balls, steel beads, ceramic beads, glass beads, and organic polymer beads having a sphere equivalent diameter of 10 cmφ to 0.05 mmφ can be used. Also, these materials are not limited to spherical shapes. It is also described in the specifications such as US Pat. Nos. 2,581,414 and 2,855,156. Also in the present invention, the magnetic coating material and the back layer coating material can be prepared by kneading and dispersing in accordance with the method described in the above-mentioned book or the references cited in the book. Hardeners and some additives (fatty acids, phosphoric acid, phosphonic acid, sulfonic acids, and their esters, which have high reactivity with magnetic materials) are added to the coating liquid just before coating using an mixing machine such as a mixing valve. You may.

As a method for coating the above-mentioned magnetic recording layer coating solution, back layer coating solution and undercoating solution on a support, the viscosity of the coating solution is from 1 to 20,000 centistokes (25).
° C) and adjust the air doctor coat and blade coat
, Air knife coat, squeeze coat, impregnation coat,
Liver roll coat, transfer roll coat,
Gravure coat, kiss coat, cast coat, spray coat, rod coat, forward rotation roll coat, carten coat, extrusion coat, bar coat, extrusion coat, etc. Can be used, and other methods are also available, and detailed explanations of these can be found in "Coating Engineering", pages 253 to 277 (published by Showa 4.3.20, published by Asakura Shoten).
Etc. in detail. The order of applying these coating liquids can be arbitrarily selected, and the undercoat layer may be continuously applied before the desired liquid is applied. When it is desired to form the magnetic layer or the back layer in multiple layers, simultaneous multilayer coating, sequential multilayer coating and the like may be performed. These are, for example, Japanese Patent Laid-Open No.
7-123532, JP-B-62-37451, JP-A-59-142741, JP-A-59-1.
It is shown in the specification of Japanese Patent No. 65239.

By such a method, about 1 to about 1 is formed on the support.
The magnetic liquid applied to have a thickness of 100 μm (solid content: 0.1 to 50 g / m ² ) is required to be 500 to 5 while immediately drying the magnetic powder in the layer at 20 to 130 ° C. in multiple stages.
About 000G in the desired direction (vertical, longitudinal, width, random,
After performing a treatment for orienting the film (obliquely), the formed magnetic layer is dried to a thickness of 0.1 to 10 μm. The transport speed of the support at this time is usually 10 m / min to 900 m / min, and the drying temperature is 20 ° C. to 130 ° C. in a plurality of drying zones.
The residual solvent amount of the coating film is controlled to 0.01 to 40 mg /
m2. In the present invention, the surface of the long magnetic recording medium is subjected to a super calendering treatment under the conditions described above to perform surface smoothing, and the center line average surface roughness of the magnetic layer and the back layer is adjusted to a desired value. Then, it is cut into a desired shape to manufacture the long magnetic recording medium of the present invention. At this time, it is preferable to use an opposing metal roll for the super calendar treatment. At this time, the conveying speed for processing the long magnetic recording medium is usually 10 m / min to 900 m / min, and the process is usually performed with a multi-stage metal roll at least twice, and the molding temperature is 50 ° C. to 130 ° C. It is preferable. For the other treatment, a combination of a metal roll, superhard plastic, and superhard plastic may be used.

In these manufacturing methods, the steps of powder pretreatment / surface treatment, kneading / dispersion, coating / orientation / drying, smoothing treatment, heat treatment, EB treatment, surface polishing treatment, cutting and winding are continuously carried out. Is desirable. These are disclosed, for example, in Japanese Patent Publication No. 40-23625, Japanese Patent Publication No. 39-28368, Japanese Patent Publication No. 47-38802, and British Patent 119.
1424, JP-B-48-11336, JP-A-4
9-53631, JP-A-50-112005, JP-A-51-77303, JP-B-52-17404, JP-A-60-70532, JP-A-2-265672.
U.S. Pat. No. 3,473,960, U.S. Pat. No. 4,728.
569, U.S. Pat. No. 4,746,542 and the like. Moreover, the method described in Japanese Patent Publication No. 41-13181 is considered to be a basic and important technique in this field.

The long magnetic recording medium thus prepared is cut and then wound on a desired plastic or metal reel. It is desirable to burnish and / or clean the long magnetic recording medium (magnetic layer, back layer, edge surface, base surface) immediately before or before winding. Burnish concretely makes a long magnetic recording medium smooth by scraping the protrusions on the surface of the long magnetic recording medium with a hard material such as a sapphire blade, a razor blade, a super hard material blade, a diamond blade, and a ceramics blade. .
The Mohs hardness of these materials is preferably 8 or more, but there is no particular limitation as long as the protrusions can be removed. The shape of these materials does not have to be a blade in particular, and a shape such as a square shape, a round shape, or a wheel (these materials may be provided around a rotating cylindrical shape) can also be used. Further, for cleaning the long magnetic recording medium, the long magnetic recording medium surface layer is made of a non-woven fabric or the like for the purpose of removing dirt and excess lubricant on the surface of the long magnetic recording medium. This is done by wiping the back side base surface. Examples of such wiping materials include various types of Vilene made by Japan Vilene and Toray made by Toray, Excene, trade name Kimwipe, various polishing tapes made by Fuji Photo Film, and non-woven fabric made of nylon, non-woven fabric of polyester, non-woven fabric of rayon, Tissue paper such as acrylonitrile non-woven fabric, blended non-woven fabric, etc. can be used. These are, for example, JP-B-46-39309, JP-B-58-46768, JP-A-56-90429, JP-B-58-46767 and JP-A-63-259830.
And JP-A-1-201824.

Hereinafter, the present invention will be described more specifically by way of examples. It will be easily understood by those skilled in the art that the components, ratios, operation sequences, etc. shown here can be changed without departing from the spirit of the present invention. Therefore, the present invention should not be limited to the following examples. In the examples, the parts are parts by weight.

[0039]

EXAMPLES Next, the present invention will be described more specifically by way of examples. In the examples, "parts" means "parts by weight". Example 1 A magnetic coating composition (1) having the composition shown below was kneaded with an open kneader, added with the composition (2) and dispersed in a sand mill, and added with (3) before coating to adjust the magnetic properties after drying. 7. Preliminary subbing layer thickness of 2.5 μm
0 μm non-magnetic support polyethylene naphthalate (MD
Direction Young's modulus of 850 Kg / mm ² and TD direction Young's modulus of 700 Kg / mm ² ).

Magnetic coating composition (1) Ferromagnetic alloy powder 100 parts (Fe metal powder, Al 5% by weight, specific surface area [S-BET]: 60 m ² / g) Phosphonic acid ester (phenylphosphonic acid) 3 parts Vinyl chloride Copolymer resin 9 parts (Nippon Zeon Co., Ltd .: MR110) Urethane resin 6 parts (Toyobo: UR8200) 2-ethylhexyl palmitate 0.5 parts Cyclohexanone 40 parts Methyl ethyl ketone 10 parts

(2) Carbon Black 0.4 parts (Conductex SC) Urethane resin 1 part (Toyobo: UR8200) Methyl ethyl ketone 10 parts or more Dispersion Abrasive (Sumitomo Chemical: Hit55) 10 parts Vinyl chloride resin 1 part ( ZEON: MR110) Methyl ethyl ketone 40 parts Cyclohexanone 60 parts or more Dispersion

(3) Polyisocyanate 3 parts (Nippon Polyurethane Co., Ltd .: Colonate 3040) Methyl ethyl ketone 50 parts Toluene 30 parts Isoamyl stearate 0.5 parts Myristic acid 0.3 parts Butoxyethyl stearate 0.5 parts

Non-magnetic support 3000 coated with magnetic paint
m was subjected to a magnetic field orientation treatment and drying in a state where the magnetic coating was not dried, and subsequently (2) was added to the following back coating (1) immediately before coating, and dried to have a thickness of 0.4 μm. After further drying, a 5-stage opposed metal calender treatment was performed at a temperature of 90 ° C., linear pressure calendar start X Kg / cm, and coated product 300.
At the end of 0 m, it was continuously changed to Y Kg / cm, heat treatment was carried out at a speed of 200 m / min, heat treatment was carried out at 65 ° C. for 24 hours, and then slit to a 1/2 inch width. The tape cleaning process was applied to the video tape by Toraysee. A list of the results is shown in Table 1.

Back coating composition (1) Carbon black 95 parts (Cabot BP800) Carbon black (Kancarb MTCI) 5 parts α-alumina (Sumitomo Chemical HIT100) 0.5 parts Barium sulfate (Sakai Chemical BF1) 0.1 parts Stearic acid 2 Ethylhexyl 0.5 part Copper oleate 0.1 part Vinyl chloride copolymer resin 50 parts (Nippon Zeon Co., Ltd .: MR110) Urethane resin 30 parts (Toyobo: UR8200) Cyclohexanone 200 parts Methyl ethyl ketone 300 parts

(2) Polyisocyanate 30 parts (Nippon Polyurethane Co., Ltd .: Coronet 3040) Methyl ethyl ketone 3500 parts Toluene 200 parts Silicone (Shin-Etsu Chemical KF69) 0.1 parts

[0046]

[Table 1]

The runnability is ◯ = 500 passes, Δ = 250.
The evaluation was performed in the range of ˜499th pass, that is, occurrence, and x = 250th pass, that is, occurrence. The gloss / Ra was evaluated by the glossiness and surface roughness of the magnetic layer at an off-center position of 3000 m. The surface roughness (Ra) of the magnetic layer was measured with a stylus surface roughness meter (Tokyo Seimitsu K, Surfcom 800A type manufactured by K). The cutoff value at this time was 0.08 mm. JIS-
It measured based on B0601. The glossiness of the surface of the magnetic layer was measured according to JIS-Z8741 at an incident angle of 45 degrees, with the specular glossiness of the black glass surface having a refractive index of 1.567 being 100%. From the examples, it can be seen that controlling the surface property in the length direction is excellent in C / N and running property with very uniform characteristics. Example 2 A magnetic coating composition (1) having the composition shown below was kneaded with an open kneader, added with the composition (2) and then dispersed with a sand mill, and added with (3) before coating to adjust the magnetic properties after drying. 7. Preliminary subbing layer thickness of 2.5 μm
0 μm non-magnetic support polyethylene naphthalate (MD
Direction Young's modulus of 850 Kg / mm ² and TD direction Young's modulus of 700 Kg / mm ² ).

Magnetic coating composition (1) Ferromagnetic alloy powder 100 parts (Fe metal powder, Al 5% by weight, specific surface area [S-BET]: 60 m ² / g) Phosphonic acid ester (phenyl phosphonic acid) 3 parts Vinyl chloride Copolymer resin 9 parts (Nippon Zeon Co., Ltd .: MR110) Urethane resin 6 parts (Toyobo: UR8200) 2-ethylhexyl palmitate 0.5 parts Cyclohexanone 40 parts Methyl ethyl ketone 10 parts

(2) Carbon black 0.4 parts (Conductex SC) Urethane resin 1 part (Toyobo: UR8200) Methyl ethyl ketone 10 parts or more Dispersion Abrasive (Sumitomo Chemical: Hit55) 10 parts Vinyl chloride resin 1 part ( ZEON: MR110) Methyl ethyl ketone 40 parts Cyclohexanone 60 parts or more Dispersion

(3) Polyisocyanate 3 parts (Nippon Polyurethane Co., Ltd .: Colonate 3040) Methyl ethyl ketone 50 parts Toluene 30 parts Isoamyl stearate 0.5 parts Myristic acid 0.3 parts Butoxyethyl stearate 0.5 parts

Non-magnetic support 3000 coated with magnetic paint
m was subjected to a magnetic field orientation treatment and drying in a state where the magnetic coating was not dried, and subsequently (2) was added to the following back coating (1) immediately before coating, and dried to have a thickness of 0.4 μm. After further drying, a 5-stage opposed metal calender treatment was performed at a temperature of 90 ° C., linear pressure calendar start X Kg / cm, and coated product 300.
At the end of 0 m, it was continuously changed to Y Kg / cm, heat treatment was carried out at a speed of 200 m / min, heat treatment was carried out at 65 ° C. for 24 hours, and then slit to a 1/2 inch width. The tape cleaning process was applied to the video tape by Toraysee. A list of the results is shown in Table 2.

Back coating composition (1) Carbon black 95 parts (Cabot BP800) Carbon black (Kancarb MTCI) 5 parts α-alumina (Sumitomo Chemical HIT100) 0.5 parts Barium sulfate (Sakai Chemical BF1) 0.1 parts Stearic acid 2 Ethylhexyl 0.5 part Copper oleate 0.1 part Vinyl chloride copolymer resin 50 parts (Nippon Zeon Co., Ltd .: MR110) Urethane resin 30 parts (Toyobo: UR8200) Cyclohexanone 200 parts Methyl ethyl ketone 300 parts

(2) Polyisocyanate 30 parts (Nippon Polyurethane Co., Ltd .: Coronet 3040) Methyl ethyl ketone 3500 parts Toluene 200 parts Silicone (Shin-Etsu Chemical KF69) 0.1 parts

[0054]

[Table 2]

The runnability is ◯ = 500 passes, Δ = 250.
The evaluation was performed in the range of ˜499th pass, that is, occurrence, and x = 250th pass, that is, occurrence. Gloss / Ra is the glossiness and surface roughness of the magnetic layer at an off-center position of 3000 m. From the examples, it is possible to obtain a long magnetic recording medium having very uniform C / N and running properties by controlling the surface property in the length direction.

[0056]

The long magnetic recording medium of the present invention is a long magnetic recording medium in which a magnetic layer containing ferromagnetic fine powder and a binder is provided on a non-magnetic support. By setting the difference in gloss of the magnetic layer between the top and the end of the hit to be less than 0.1% and the Ra difference to be less than 0.02 nm, high output and high density recording with excellent running durability in the longitudinal direction of the tape. A long magnetic recording medium can be obtained. Furthermore, in a long magnetic recording medium provided with a magnetic layer containing a ferromagnetic fine powder and a binder on a non-magnetic support,
A high output in the longitudinal direction of the tape is produced by a manufacturing method in which the difference in gloss of the magnetic layer between the top and the end of the long magnetic recording tape 100 m is less than 0.1% and the difference in Ra is less than 0.02 nm.
It is possible to obtain a long magnetic recording medium which is excellent in running durability with high density recording. Further, the present invention provides a long magnetic recording medium which eliminates quality differences in the longitudinal direction of the long magnetic recording medium, has little variation between lots, and has extremely excellent running durability such as wear characteristics and friction characteristics. it can. When one roll is calendered in the manufacturing process of long magnetic recording media, the calender pressure is temporarily increased from the start to the end, or the calender temperature is temporarily increased, so that the tape runs in the longitudinal direction with high output and high density recording. It is possible to obtain a long magnetic recording medium having extremely excellent properties. When heat-treating a long magnetic recording medium at 40 ° C. or higher for 4 hours or longer, the roll core side has a rougher surface than the outside and has a low glossiness, and after heat treatment, the surface properties and glossiness of the roll core side and the outside are By substantially eliminating the difference, it is possible to obtain a long magnetic recording medium having high output / high density recording and extremely excellent running durability in the tape longitudinal direction. Further, in the present invention, it is possible to eliminate the quality difference in the longitudinal direction of the long magnetic recording medium, to obtain a long magnetic recording medium which has little variation between lots and is extremely excellent in running durability such as wear characteristics and friction characteristics. You can

Claims (6)

[Claims] 1. A long magnetic recording medium in which a magnetic layer containing ferromagnetic fine powder and a binder is provided on a non-magnetic support, and heat treatment is performed after calendering. A long magnetic recording medium, characterized in that the difference in glossiness between the top and the end of the magnetic layer is less than 0.1%, and the difference in Ra is less than 0.02 nm. 2. A long magnetic recording medium in which a magnetic layer containing a ferromagnetic fine powder and a binder is provided on a non-magnetic support, and heat treatment is performed after the calender treatment.
A long magnetic recording medium after the heat treatment, in which the magnetic layer on the roll core side has a rougher surface (Ra) and lower gloss than the outer magnetic layer in a state of being wound around a roll after the heat treatment. 100
2. The long magnetic recording medium according to claim 1, wherein the difference in glossiness between the top and the end of the magnetic layer per m is less than 0.1% and the difference in Ra is less than 0.02 nm. 3. A magnetic layer containing ferromagnetic fine powder and a binder is provided on a non-magnetic support, calendered, and then the obtained long magnetic recording medium is heat-treated at 40 ° C. or higher for 4 hours or longer. In the method for manufacturing a long magnetic recording medium,
A method for producing a long magnetic recording medium, characterized in that, in the calendering process, the calender pressure is increased for a while from the beginning to the end of one roll. 4. The calender pressure is set to 200 kg / cm to 350 kg / cm at the head of the one roll,
Raise it for a while and set the calender pressure to 220kg at the end.
/ Cm to 400kg / cm, the pressure difference is 20kg
3. The method for producing a long magnetic recording medium according to claim 2, characterized in that the magnetic recording medium has a thickness of / cm to 200 kg / cm. 5. A magnetic layer containing ferromagnetic fine powder and a binder is provided on a non-magnetic support, calendered, and then the obtained long magnetic recording medium is heat-treated at 40 ° C. or higher for 4 hours or longer. In the method for manufacturing a long magnetic recording medium,
A method for producing a long magnetic recording medium, characterized in that in the calendering process, the calender temperature is raised for a while from the beginning to the end of one roll. 6. The calender temperature is set at 50 ° C. to 100 ° C. at the leading end of the one roll and is temporarily raised, and the calender temperature is set at 60 ° C. to 110 ° C. at the end, and the temperature difference is 5 ° C. to 40 ° C. 5. The method for manufacturing a long magnetic recording medium according to claim 4, wherein: