JPS59117734A - Magnetic recording medium - Google Patents

Abstract

PURPOSE:To obtain a magnetic tape reducing drop-out and preventing electrostatic charge and the clogging of a head by curing a layer contg. a surfactant or the surfactant and a pigment dispersed in a binder contg. a radiation sensitive resin on the surface of a support opposite to a magnetic layer. CONSTITUTION:A back layer contg. an anionic, cationic, nonionic or amphoteric surfactant dispersed as an antistatic agent in place of carbon black, graphite or the like in a binder contg. a radiation sensitive resin is formed on the surface of a magnetic tape opposite to the magnetic layer. The amount of the surfactant is 1-20pts.wt. per 100pts.wt. binder resin, and SiO2, Al2O3, ''Teflon'' powder, MoS2, chrome yellow, oil red or other pigment may be further dispersed in the binder so as to prevent the bleeding of the surfactant. The magnetic layer is made of gamma-Fe2O3, gamma-Fe2O3 doped with Co, a magnetic metal or the like. The clogging of a magnetic head with magnetic powder released from the tape during traveling and drop-out are prevented, and the life of the magnetic tape and the life of the head can be prolonged.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a magnetic recording medium, and more specifically, the surface roughness of the back layer can be ignored by using a surfactant instead of carbon black, graphite, etc. in the back layer, and the bank layer The present invention relates to a magnetic recording medium that has been improved so as to be able to take full advantage of the flexibility of the resin.

At present, magnetic tape has come to be widely used in the audio, video, and computer fields. Along with this, the amount of information recorded on media has increased year by year, and media are increasingly required to have high recording density.

In current recording systems using magnetic helenoids, the spacing loss between cheap healds is 54. It is expressed as [i'λ (dB) (d: distance between the tapes, λ: recording wavelength). As can be seen from this equation, in short wavelength recording with high recording density, the rate of output reduction due to spacing is significantly greater than that in long wavelength recording. Therefore,
Even if a small foreign object is present on the tape surface, it will be detected as a dropout.

Possible causes of dropouts include falling off of magnetic powder from the surface of the magnetic tape coating due to deterioration of the coating due to repeated stress, or magnetic powder being scraped off during running, or due to scratches such as It may be electrostatically attached to the base surface and then transferred to the coating surface.

In order to prevent this, for example, following the latter cause,
Magnetic tape o> Tl? A method was devised in which a paint made by kneading carphone black or graphite with a proprietary binder was applied to the surface of the support (the hack side) opposite to the steel surface to strengthen the heath and reduce the possibility of abrasion of the heath. ing. Through these processes, the tendency for dropouts to increase due to repeated running can be significantly suppressed. However, the degree of dropout is not perfect, and it is necessary to further reduce dropout. The applicant has submitted a patent application filed in 1986-543 to find out the cause of the occurrence in detail.
It is written in No. 62.

Moreover, Tsufu thermosetting resin is used as a binder.

In that case, after the hack layer has been applied, the tape will be wound up and subjected to a heat curing treatment. However, at the time the coating is finished, the curing reaction has not yet started in the hack layer and the coating is weak.Moreover, the hack surface and the magnetic surface are in close contact with each other, so the coating is filled into the hack layer coating. Hacked surface coatings containing carbon black, graphite, or other inorganic fillers tend to transfer to the magnetic layer surface on the opposite side with which they are in contact, resulting in dropouts and head defects. It turns out that this is one of the causes of blockages. Furthermore, it is thought that this phenomenon may occur even with pi (plastic resin).

By providing a hack layer, it is possible to suppress an increase in dropouts due to repeated running, but this is the reason why dropouts are not so low when the number of runs is small.

In order to eliminate the above-mentioned problems in the hack layer formation process, we use radiation-sensitive resin (resin that can be cured by irradiation with radiation).
After forming a hack layer with a paint kneaded with carphone black or graphite or other inorganic fillers as a binder, irradiation is performed with an active energy ray source,
After applying a hardening treatment, or directly performing a surface treatment and then a hardening treatment to create three-dimensional crosslinking in the adhesive layer and create a strong coating film, each time the tape is wound, the above-mentioned There are things that can cause a decrease in ``to1'' due to such causes. According to this method, the tape is wound up after the crosslinking reaction of the coating film has finished, so even if the hack layer or the magnetic layer G is brought into close contact with each other during winding, no transition from the hack layer to the magnetic layer occurs. It says no.

However, unless a large amount of carbon black, graphite, etc. is added to the resin, there will be no effect on static electricity.If such a large amount of carbon black, graphite, etc. is added, the surface roughness of the back layer becomes a problem. , the output decreases in the magnetic layer.

The object of the present invention is to solve the above-mentioned drawbacks by using a surfactant instead of carbon black, graphite, etc., which prevents static electricity, makes the surface roughness of the bank layer negligible, and further improves the resin of the back layer. The object of the present invention is to provide a magnetic recording medium that can fully utilize the effect of flexibility and lead to an increase in output.

The radiation-sensitive resin used in the present invention is one that contains two or more unsaturated double bonds in its molecular chain, such that radicals are generated by radiation to form a crosslinked structure, and this is also a thermoplastic resin. It is also possible to make the radiation sensitive to radiation.

A specific example of radiation-sensitive modification is acrylic acid, which exhibits an unsaturated double bond that is radically polymerizable.

Acrylic double bonds such as methacrylic acid or its ester compounds, allylic double bonds such as diallyl phthalate, unsaturated bonds such as maleic acid and maleic acid derivatives! It is the introduction of a group into the molecule that can be crosslinked or polymerized and dried by radiation irradiation.

Any unsaturated double bond that undergoes cross-linking polymerization upon irradiation with radiation can be used.

One thermoplastic product/one resin that can be modified into a radiation-sensitive resin is shown below.

(2) Hinyl chloride-based copolymer, hinyl chloride-hinyl acetate-hinyl alcohol copolymer, hinyl chloride-hinyl alcohol copolymer, hinyl chloride-hinyl alcohol-zoropionate copolymer, hinyl chloride-hinyl chloride copolymer Acetate hinyl-maleic acid copolymer.

Hinychloride-Hynylacetate-terminated OH side alkyl group copolymer, for example, UCC (1+1.VYNC).

Examples include V V FG X, and UCC's VERR.

By the method described later, an acrylic double bond, a maleic acid double bond, and an allylic double bond are introduced into the L copolymer to perform radiation sensitivity modification.

(+)) Saturated polyester resin phthalic acid, isophthalic acid 7-thiophucric acid, succinic acid,
Saturated polybasic acids such as adipic acid and sebacic acid and ethylene glycol, ethylene glycol, glycerin,
1-lyncholpropane, 1.2 propylene glycol, 1.3 fucundiol, dipropylene glycol,
1.4 Phthanediol 11.6 Hexane diol, pentaerythritol, solhitol, glycerin, neopentyl glycol, 1.4 Saturated polyester resins obtained by ester bonding with polyhydric alcohols such as cyclohexane dimetatool, or polyesters thereof A resin modified with 50λNa etc. (Vylon 53S). Radiation sensitivity degeneration is performed using the methods described below.

(c) An unsaturated polyester resin molecular chain containing a radiation-curable unsaturated double bond, e.g. Radiation-curable unsaturated polyester resin containing unsaturated double bonds, prepolymer, Oli-1, which is made by combining a part of polybasic acid with inic acid and saturated polyester resin consisting of ester bonds.
Can raise a mark.

Examples of the polybasic acid and 1i+1i alcohol components of the saturated polyester resin include the compounds listed in item (a), and examples of the radiation-curable unsaturated double bond include maleic acid and fumaric acid. I can do it.

The manufacturing method of radiation-curable unsaturated polyester resin is to add one or more polybasic acid components, one or more polyhydric alcohol components, maleic acid, fumaric acid, etc.
After dehydration or dealcoholization reaction in a nitrogen atmosphere at 80-200°C, the temperature is raised to 240-280°C, and 0.5-1
A polyester resin can be obtained by condensation reaction of 11 g of mm under reduced pressure. The content of maleic acid, fumaric acid, etc. is determined by the crosslinking of the manufacturing ribs.

From the viewpoint of radiation curability, etc., it is 1 to 40 mol%, preferably 10 to 30 mol%, in the acid component.

((j) Borihinyl alcohol resin Borihinyl alcohol, phthyral + AJ resin, acecool resin, Polmar resin, and copolymers of these components. The hydroxyl groups contained in these resins are modified by radiation sensitization using the method described later. conduct.

(e) Epoxy resin, phenoxy resin Epoxy resin produced by the reaction of hisphenol A, epichlorohydrin, and medyl epichlorohydrin - manufactured by Ciel Chemical (Epicor 1)
-152.154,828°1001.1004.10
07), manufactured by Dow Chemical (1) EN 431°DER
732, DI MiR511, DER331), manufactured by Dairoki Ink (Ebikuron-400, Ebikuron-800),
Furthermore, phenoxy resin manufactured by UCC (PKHA, PKIIC, P former 111) which is a high polymerization degree resin of epoxy mentioned in -
Copolymer of brominated hisphenol A and Epicron [copolymer with colhydrin, manufactured by Dainippon Ink and Chemicals (Epicron 1.45
．． 152.153.1120) etc.

Radiation sensitivity modification is performed using the epoxy groups contained in these resins.

(f) Cellulose derivatives Cellulose derivatives of various molecular weights are also effective as thermoplastic components. Among these, particularly effective ones are nitrified cotton, cellulose ace-1-hebutyrate ethylcellulose, butylcellulose, acetylcellulose, etc., and radiation sensitivity modification is carried out by activating the hydroxyl groups in the resin and using the method described later.

In addition, it is used for radiation sensitivity degeneration. Resins that can be used with 2 include polyfunctional polyester resins, polyether ester resins, polyhinylpyrrolitone resins, and derivatives (1')
VP olefin copolymer), polyamide resin, polyimide resin, phenolic resin.

Also effective are SpillJ acecool resin and acrylic resins containing acrylic esters and methacrylic esters containing hydroxyl groups as polymerization components of at least type I.

Furthermore, by blending the radiation-sensitive modified thermoplastic resin G with a thermoplastic elastomer or prepolymer, a tough coating film can be obtained. Furthermore, as described below, it is more effective if these elastomers or prepolymers are similarly modified to be radiation sensitive. Listed below are elastomers or prepolymers that can be combined with the radiation-sensitive resin described above.

(g) Polyurethane elastomers, prepolymers and telomers Polyurethane superlaminants are particularly effective in terms of good abrasion resistance and good adhesion to POET films.

Examples of such urethane compounds include 2,4-1-ruene diisonanate 26-
tolunincyisocyanate 1.3-xylene diisocyanate, 1.4-xylene diisocyanate, 1.5-
Naphthalene diisocyanate, m-phenylene diisocyanate, p-phenylene diisocyanate, 3.3°-dimethyl-4,4°-diphenylmethane diisocyanate, 4.4'-cyphenylmethane diisocyanate-1-,3,3'-dimethyl Hyphenylene diisocyanate, 4.4'-hyphenylene diisocyanate 1~. Hexamethylene diisocyanate 1-.

Various polyvalent isocyanates such as isophorone diisocyanate, dicyclohexylmecune diisocyanate, Desmodur L, and Desmodur N, and linear saturated polyesters (ethylene glycol, diethylene glycol, glycerin.

1-lyncholpropane, 1,4-butanediol,
1.6-hexanediol, pentaerythritol, sorbitol, neopentyl glycol.

1. Polyhydric alcohols such as 4-cyclohexane dimetatool and phthalic acid, isophthalic acid, terephthalic acid, succinic acid, adipic acid, sebacic acid.

(condensation polymerization with saturated polybasic acids such as A polyurethane lath 1-mer made of a condensation product of polyester,
Prepolymers and telomers are effective.

These elastomers may be combined with various types of radiation-sensitive plastics, but
Furthermore, the isocyanate 1-mer at the end of the urethane elastomer
By reacting with a monomer having an acrylic double bond or an allylic double bond that reacts with a group or a hydroxyl group,
Modification to radiation sensitivity is effective for non-lightning.

(h) Acrylonitrile-butadiene copolymer elastomer An elastomer such as an acrylonitrile-butadiene copolymer prepolymer with a terminal hydroxyl group commercially available as PolyBD Liquisodorecin manufactured by Sinclairvetro Chemical Co., Ltd. or Hiker 1432 J manufactured by Nippon Zeon Co., Ltd. ,
In particular, the double bond in butadiene generates radicals when exposed to radiation, leading to crosslinking and polymerization as an elastomer component.

(i) Polybutadiene Elastomersin A prepolymer having a low molecular weight terminal hydroxyl group, such as PolyBD Liquisotresin R-15 manufactured by Apetrochemical Co., Ltd., is particularly suitable in terms of compatibility with thermoplastic resins. R-
Since the 15 prepolymer has a hydroxyl group at the end of the molecule, it is possible to increase the radiation sensitivity by adding an acrylic unsaturated double bond to the end of the molecule, making it more advantageous as a binder.

In addition, polybutadiene cyclized product Nippon Synthetic Rubber Co., Ltd.
-M! 101 is also effective in combination with thermoplastic resin. In particular, cyclized polybutadiene has a high efficiency of crosslinking polymerization by radiation due to the radicals of unsaturated bonds inherent in polybutadiene. It has excellent properties as a binder.

Suitable geothermal plastic elastomers and prepolymer systems include styrene-butadiene rubber, chloride comb, acrylic comb, isoprene comb, and their cyclized products (Japan Synthetic Rubber 141clR7 (It), 1 Boquin modified comb, internally plasticized saturated Linear polyester (I l″(-
Elastomers such as MJj Byron #-300) can also be used for a-effect by subjecting them to the radiation sensitivity modification treatment described below.

Furthermore, it is known that some polymers disintegrate when irradiated with radiation, while others cause cross-linking between molecules. Examples of substances that cause crosslinking between molecules are poly and ethylene.

Polypropylene 2 polystyrene, polyacrylic acid ester, polyacrylamide, polyhynyl chloride, polyester, polyhynyl pyrrolidone rubber.

There are polyhinyl alcohol and polyacrolein. If such a crosslinked polymer is used, the crosslinking reaction will occur even without special modification as described in 1-, so it can be used as is as a backcoat resin for radiation crosslinking.

Furthermore, according to this method, even a solvent-free resin that does not use a solvent can be cured in a short time, so such a resin can also be used for hack coating.

The surfactant as an antistatic agent used in the present invention is
Examples of the anionic acid salts include carbonic acid salts, sulfuric acid derivatives, phosphoric acid derivatives, pentaalkyl boribosphate, hexaalkyl boribosphate, dialkylphosphonic acid, sulfonic acid, and the like.

Examples of cationic types include amines, quaternary ammonium salts, imidasoline, amine oxidized ethylene adducts, and quaternary phytic acid.

Nonionic types include polyhydric alcohols, polyalcohol esters, alkylphenol ethylene oxide compounds, fatty acid ethylene oxides, amino]・ethylene oxide f
These include amine oxide, ethylene oxide, amyl, and the like.

Amphoteric types include carboxylic acids, sulfonic acids, metal salts, and alkylhetaines.

If the amount of surfactant is less than 1 part by weight based on the resin, the hack layer will not be effective in preventing static electricity, and if it exceeds 20 parts by weight, it will cause stains on the surface. Undesirable.

In addition, these surfactants include acrylic CH at the end.

By adding a double bond, Cl1z = CC00C11
2SOJ It.

CI+, (+ 11 Cllz -C-(nee 0-- CG-R7-C(l
R, - (1) Jl or
CI (2=ClICOOR, CI+, -
CIICONHCI+20COR (I7 is Cnllzr
m −+ Cn1lzn −, Cn1Lzn-x, etc.), etc.), the dispersibility and percent property are improved, and the acrylic double bond generates radicals by radiation treatment and becomes a binder component. It reacts with the generated radicals to form a strong bond, resulting in even better surface properties.
Electromagnetic properties are also improved.

In addition, in order to prevent the surfactant in the back IN from seeping out and dislocating to the magnetic layer during high-temperature storage, pigments such as 5i07, Ti0z, 8l, and Q are added as necessary.
I.

CrzO3, SiC, CeO>, CaC0J, zinc oxide, casite, αFezOa, Kuruk, kaolin, (:aSOu, boron nitride, Teflon powder, graphite fluoride, molybdenum disulfide, zirconia, Ca5i
02. Asbestos titanium white, white carphone, chrome yellow.

Oil yellow, oil blue, oil 1/7 dot, etc. are added as appropriate.

Incidentally, the surfactant and the pigment are not necessarily used one by one, but two or three kinds may be mixed.

In addition, the active energy rays used for crosslinking the hack coat of the present invention include electron beams using a radiation accelerator as a radiation source;
γ-rays using CO'° as a radiation source, β-rays using Sr'' as a radiation source
X-rays, X-rays using an X-ray generator as a radiation source, ultraviolet irradiation, etc. are used.

In particular, as an irradiation source, it is advantageous to use radiation using a radiation heater from the viewpoints of controlling the absorbed dose, introducing it into the manufacturing process line, and shielding ionizing radiation.

The radiation characteristics used when curing the hack layer are as follows:
From the perspective of penetrating power, a radiation accelerator with an accelerating voltage of 100 to 750 KV, preferably 150 to 300 KV is used to reduce the absorbed dose to 0.
．． C1 scream (it is convenient to shoot 6 times) to get 5 to 20 megarads.

When curing the hack layer of the present invention, a low-dose type radiation A/J-ray accelerator (Elecrocurtain System) manufactured by Enercineaience Inc. in the United States and an accelerator manufactured by RP Co., Ltd. are used to apply tape cop ink. Introduction to Niline,
This is extremely advantageous for shielding secondary X-rays inside the accelerator.

Of course, a van de Graaf type accelerator, which has been widely used as a radiation accelerating material, may also be used.

In addition, when crosslinking with radiation, it is important to irradiate the hack layer with radiation in an inert gas stream such as N scum or 11e gas. This is extremely disadvantageous because it prevents the radicals generated in the polymer from working advantageously in the crosslinking reaction.

Therefore, the atmosphere in the area where the active energy source is irradiated is
In particular, Nl, lle, CO2 with a maximum oxygen concentration of 1%
It is important to maintain an inert gas atmosphere such as

In the case of ultraviolet irradiation, add 1 to
Contains 10% by weight of photopolymerizable sensitizer.

In the case of ultraviolet rays, the influence of inert scum is less than that of electron beams, so irradiation in the atmosphere is possible. If the amount of pigment is too large, the coating film will become brittle. Therefore, 20
A suitable amount is 0 parts by weight or less.

Furthermore, such a puncture layer should be provided on magnetic tape and ζ for audio tape and video tape.

-2mbi, 7. Among them, it is quite effective to use it for video tapes and combination J-ter tapes, in which dropout is one of the most important characteristics.

The magnetic fine powder contained in the magnetic P1° paint is αPeJ3
゜FerOw, Co-doped rFezoJ+co-doped r
Fe2O, + -Pei (Ig solid solution, CrO
gco-based compound adhesion type r Fe2O3゜Co-based compound adhesion type PejOy (including intermediate oxidation state with γl' ex OJ ~Ferrite:
A case is shown in which the magnetic anisotropy of cobalt, such as a 1-pal 1-ion adsorbent, is utilized to improve coercive force. ), also 00°Fe-Co
The main component is a ferromagnetic metal element such as , Fe-Co-Ni, Co-Ni, etc. The manufacturing method is a reduction method using a reducing agent such as NaBIls, or after treatment of the iron monoxide surface with a Si compound.
Examples include a dry reduction method using 1z gas or the like, or a method obtained by generating a vacuum in a low-pressure argon gas stream. Also, single crystal Hariu J Ferrite i7i' (powder can also be used).

The above-mentioned magnetic fine particles have an acicular shape or a grain shape, and are selected depending on the purpose of use as a magnetic recording medium.

Further, the binder may also be thermoplastic, curable, or radiation curable.

On the other hand, it is also effective to use a lubricant in the bank layer depending on the purpose.

Examples of photosensitizers include henzoin, henzoin methyl ether, benzin ethyl ether, henzoin isopropyl ether, α-methylhenzoin, α-phenylhenzoin, and other hendiin compounds, anthraquinone, methylanthraquinone, and the like. anthraquinone compounds, phenylkene compounds such as hensyl diacetyl, acetophenone, hensifhenone, sulfide compounds such as diphenyl disulfide and tetramethylthiuram sulfide, α-chloromethylnaphthalene, anthracene and hexachlorobutadiene, pentachlorobutadiene, etc. Examples include halogenated hydrocarbons. The photopolymerization sensitizer is 0.1 to 10% based on the solid content of the resin.
A range of is desirable.

Below 1: Examples will be described.

[Example 1] Acrylic modified salt arsenic acid arsenic alcohol copolymer (n) 60 parts 7 Acrylic modified 1 raw polyurethane conylas 1-mer (g) 4
Part: Quaternary ammonium salt: 7 parts: Mixed solvent: 600 parts The above mixture was heated to 11 for 5 hours in a ball mill, applied to the back side of a polyester film on which a magnetic surface was formed to a dry thickness of 0.1 μm, and electrolyzed. Using a curtain type electron beam accelerator, the acceleration voltage was 1.50KV.
, electrode current 10 mA, absorption line 15 Mrad, the hack layer was irradiated with an electron beam in N2 scum, cured, wound up, cut into 1/2'' Hideo RP, and tested with a V HS tenoki for sensitivity (4 MIIz). was measured.

[Comparative Example 1] In Example 1, Si was used instead of the quaternary ammonium salt.
100 parts by weight of O was added.

As shown in Table 1, it can be seen that there is a sensitivity amplifier when the layer is made of a radiation-sensitive resin and a surfactant. It can be seen that the influence of the hack layer is significantly different.

[Example 2] Acrylic modified polyester resin 100 parts Phosphoric acid ester derivative consisting of alcohol 2 parts Mixed solvent 600 parts 0.2μ coating [Example 3] Vinyl chloride, vinyl acetate alcohol copolymer 60
Part acrylic modified polyurethane elastomer 1-mer 40 parts Part 3
grade amine 100 parts/8 sentences
61) Of! B Table 2 (), 1 μ coating Example 3, 1 to 211 for a short period of time under high temperature and humid storage
There were no problems during storage, but for 3 days Z (A) was added to Ingredients I-, and the surfactant crab 7 in the hack layer became sticky.
ζI didn't like it. Then, when I added pigment 5i02, the stickiness was suppressed and the low output of 1F was only slight.

Therefore, it is effective to add pigments as necessary. This is shown in Example 4.

[Example 4] For Example 3 5iOL20 parts by weight 1　μ coating Table 3 On a scale of 5 to 1, 1 is the best.

[Example 5] In contrast to Example 4, the above composition was irradiated with ultraviolet rays using 3 parts of hengeine ethyl ether. The coating thickness was set to lμ.

Table 4 It was found that as the amount of pigment was increased, the electromagnetic conversion characteristics also deteriorated, and when the amount exceeded 200 parts by weight, the coating film became brittle. If it is within 200 parts by weight, the sensitivity is 10 F1.4 dI
It was better than 1.

The present invention has been variously explained below with reference to preferred embodiments, but the present invention is not limited to these embodiments, and it goes without saying that many modifications can be made without departing from the spirit of the invention. It is.

Patent Applicant Tokyo Denki Kagaku Kogyo Co., Ltd. Representative Fukujibe Sono (7762) Patent Attorney 1 Procedural Amendment 1, Case Description Showa 5741E4'1 Application No. 231 (197 No. 2, Name of Invention Magnetic Recording) Medium 3, Relationship with the case of the person making the amendment Patent ε'1, Ex. to correct.

1. In a magnetic recording medium in which a magnetic layer is provided on one side of a support and a hack layer is provided on the other side, the hack layer is a binder phase containing a radiation-sensitive resin and contains a surfactant and A magnetic recording medium characterized in that it can be hardened for a minute t1!! if necessary.

2. Pigment, 5i(la, Tie,, 8I, [],
, Cr, 0. .

Sic, CeO,, Ca[:O,, j! II,
111i 19, -Oh! G1 Otsu-)1 (J
t Goji Ikkin, αl'e, 03, Kuruku, Kaolin, C+1SO4.

Boron nitride, Teflon 1'5) powder, lead for sonification, moriso sulfide, norconia, la SiOz
, 7z's \sl, -J-tanbowight, 11no, (
+・Carphone.

ri1-I), ie +: r-, J ile ie +: +-,;(
Il true or oil let 4"I'A'l"
The magnetic recording medium according to item 1, which is the range of nIf.

3. The magnetic layer is r FezJ, Co-topped γl B,
Ll 3 + l made of metal [Claim 1]
Jnmata d 21st, fi-kisen magnetic recording medium.

4. The magnetic recording medium according to claim 1, 2, or 3, wherein the radiation is an electron beam.

5. Further 1 to 10% by weight of radiation-curing paint in the binder
The magnetic recording medium according to claim 1, 2, or 3, wherein the magnetic recording medium contains a photopolymerizable sensitizer and has a back layer formed by irradiation with ultraviolet rays. j 2) "Kahlite" on page 18, lines 11 to 12 of the specification is corrected to "iron oxyhydroxide."

3) [αFe process O, J on page 21, line 6 of the specification]
Feyo0. ” he corrected.

Claims (1)

[Claims] 1. A magnetic recording medium in which a magnetic layer is provided on one side of a support and a bank layer is provided on the other side, in which the radial layer is filled in a binder containing a radiation-sensitive resin. A magnetic recording medium characterized in that it is obtained by dispersing and curing a surfactant and, if necessary, a pigment. 2. The pigment is 5iOz, TiO2,^1,03,
Cr2+1.3. SiC, Ce(lz, CaC0J, zinc oxide, goethite. αFezO3, talc, kaolin, Ca5Op, boron nitride, Teflon powder, graphite fluoride, molybdenum disulfide, zirconia, Ca5iOz, asbestos. Nakumboyite, white carbon, chromite l”
-, oil yellow, oil blue or oil red. 3. The magnetic recording medium according to claim 1 or 2, wherein the magnetic layer is made of r Fe 20 J , Co-doped γre, O,, metal. 4. The magnetic recording medium according to claim 1, 2, or 3, wherein the radiation is an electron beam. 5. Further 1 to 10% by weight of radiation-curing paint in the binder
The magnetic recording medium according to claim 1, 2, or 3, wherein the magnetic recording medium contains a photopolymerizable sensitizer and has a bank layer formed by irradiation with ultraviolet rays.