JPS589489B2 - Jikiki Rokutai - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a magnetic recording medium, and particularly to the composition of a protective layer provided to protect a magnetic recording layer.

As a protective layer for magnetic recording tape, after the magnetic layer has dried,
A silicone resin and an isocyanate compound are coated separately or in a mixture to a thickness of 1 μm or less and dried (Japanese Patent Publication No. 48-41883), and a layer of MoS2/graphite of 6/1 to 1/3, preferably 2/1~1/10
Apply a mixture of proportions from 0.0215 to 0.538 mg/m2 [West German Patent (DT-AS) No. 1572438]
etc. are known.

In addition, as a protective film related to magnetic cards, a protective film of polymethacrylic acid ester or its copolymer (Japanese Patent Application Laid-Open No. 1983-1999) is used.
No. 28904), a mixture of nitrocellulose and isocyanate and a protective film of polymethacrylic acid ester copolymer (No.
JP-A-47-30302), polymethacrylic acid ester copolymer protective film (JP-A-47-30303), multilayer protective film combining a soft protective layer and a hard protective layer (JP-A-47-30304) (No. 47-24804), a protective layer containing an acetal resin and a thermosetting resin (Japanese Patent Application Laid-open No. 47-24804), and a type in which a special polymer film is laminated on a magnetic layer are also known. There is.

Also known is a protective layer (US Pat. No. 3,476,595) in which a condensate of polysiloxane and a polymer is provided in a thickness of 0.08 to 0.8 μm under the name of a lubricating layer.

The conventional protective layer for a magnetic recording medium such as the one described above has the following drawbacks.

■ When the protective layer is multilayered, the coating process becomes complicated and the number of steps increases.

■ Laminating polymer films requires a sufficiently thin film, which poses problems in selecting adhesives and the like when laminating, and it is difficult to laminate uniformly when thermally bonding.

■ Products with abrasive fine powder mixed in the protective layer have a problem of high head wear.

(2) When a finely powdered inorganic lubricant is used, the fine powder scatters during repeated use, which is undesirable.

■ Other known protective films do not exhibit sufficient strength in terms of durability during repeated playback.

Especially recently, magnetic materials containing cobalt have Hc of 400 to 150.
Phenomena such as heating demagnetization are observed when the size is increased to about 00e, but it is an effective means to prevent demagnetization by providing a protective film for these magnetic materials, and the protective film with the composition of the present invention is intended to compensate for the shortcomings of the above-mentioned ■α.

The objects of the present invention are shown below.

1. To provide a protective film for magnetic recording media with excellent wear resistance.

2. Provides a protective film with excellent adhesion to the magnetic layer.

3.Provides a protective film with little change over time.

4. To provide a protective film that causes less head wear.

5. Provides a scratch-resistant protective film.

6. Provides a protective film with excellent heat resistance.

7. To provide a protective film that will not be thermally imprinted on the press plate even when hot pressing is performed when making magnetic cards.

8. To provide a protective film that is less dependent on humidity.

9. A protective film for reducing demagnetization of a magnetic layer containing a cobalt-containing magnetic material is provided.

That is, the present invention provides a magnetic recording material in which a magnetic layer mainly composed of ferromagnetic fine powder and a binder is provided on a nonmagnetic support, and further has a protective film thereon, in which the protective film is made of a cellulose derivative, an epoxy resin, or a polyamide. This is a magnetic recording medium characterized by being made of resin.

The cellulose derivatives used in the protective layer of the present invention are cellulose esters and cellulose ethers. Cellulose esters include cellulose diacetate, cellulose triacetate, nitrocellulose, cellulose acetate butyrate, nitrocellulose acetate, and cellulose ethers include methyl cellulose. , ethyl cellulose, propyl cellulose, butyl cellulose, benzyl cellulose, etc. are used.

Mixtures of these can also be used.

It is preferable to use a cellulose derivative having a degree of polymerization of about 20 to 10,001, preferably 30 to 500.

Epoxy Jugetsu Uma A synthetic resin containing two or more epoxy groups (-CH2-CH-CH2), which is a copolymer of an epoxy compound and its salts represented by the following general formula [I] and an addition polymerizable monomer. It is.

(In the formula, R1, R2 and R3 are CnH2n+1 (n=0
-6 integer), R4 represents a monovalent group having an addition polymerizable group having 2 to 9 carbon atoms.

) Specifically, the epoxy-containing monomers of the above general formula (I) are halogenated bisphenol type, resorcinol type, and bisphenol F type (using formaldehyde instead of acetone in the synthesis of bisphenol).
All epoxy group-containing monomers such as tetrahydroxyphenylethane type, novolak type, polyalcohol, polyglycol type, glycidyl ether type such as glycerin triether type, polyolefin type, epoxidized soybean oil type, alicyclic type, etc. Contains.

In addition, monoepoxidized diolefins, glycidyl acrylate, glycidyl methacrylate, aryl glycidyl ether, vinyl glycidyl ether, p-vinylphenyl glycidyl ether, and the like can also be used.

These epoxy groups do not cause a crosslinking reaction by themselves, but in the presence of a proton donor, they form a crosslinking bond through a ring opening reaction.

In the case of epoxy groups, it is therefore necessary to use acidic catalysts or alternatively to combine them with proton donor functions.

Specifically, the crosslinking reaction rate of an epoxy group alone, an epoxy group and a hydroxyl group, or a combination of an N-methylol ether group is very slow in the absence of a catalyst, but with the addition of an acidic catalyst such as p-toluenesulfonic acid. significantly promoted by

On the other hand, in the case of a copolymer that combines an epoxy group and a carboxyl group, the crosslinking reaction is extremely fast even without a catalyst, and exhibits the highest reactivity among these functional groups.

Furthermore, the speed of the crosslinking reaction varies depending on the type of unsaturated monomer for introducing a carboxyl group, and the order is itaconic acid>methacrylic acid>maleic anhydride.

The reason why maleic anhydride has a low crosslinking rate can be explained by the presence or absence of proton retention.

The epoxy resin represented by the above general formula (i) can be produced by (A) a reaction between epihalohydrins and a polyhydroxy compound (polyol), (B) a reaction between an epihalohydrin and a polycarboxylic acid, or (C) an ozone oxidation of a polyene or a peracid. Synthesized by oxidation etc.

As the epihalohydrin in cases (A) and (B), shrimp chlorohydrin, methylepichlorohydrin, shrimp bromohydrin, etc. are used.

In the case of (A), the polyhydroxy compounds include bisphenol A (4,4'-dioxydiphenylpropane)-diaminodiphenylpropane, 4,4'-dioxyphenylmethane (bisphenol F), diphenolic acid,
Tetrahydroxyphenylethane, 3・3′・3″・3
'''-Tetraoxytetraphenylethane, resorcin, resorcin-3-methoxyphenol, resorcin-
Aromatic polyhydroxy alcohols such as 4-ethoxyphenol and Novolak Jugeki; aliphatic di- and tri-alcohols such as diethyl alcohol, trimethyl alcohol, triethyl alcohol, and trimethyl alcohol; polyalkylenes such as polyethylene oxide and polypropylene oxide Aliphatic diglycols and triglycols consisting of oxides: glycerin
Glycerin ethers such as 1,3-diethyl ether, glycerin ether, glycerin triethyl ether, glycerin methyl diethyl ether, ethylene oxide, and propylene oxide are used.

In the case of (B), the polycarboxylic acid is azelaic acid,
2,4-benzophenone-dicarboxylic acid, Brazilian acid,
1,4-cyclohexanedicarboxylic acid, fuma4, glutaric acid, α-ketoglutaric acid, itaconic acid, maleic acid,
Aliphatic or aromatic dibasic acids such as malonic acid, octadecylmalonic acid, pimelic acid, phthalic acid, isophthalic acid, terephthalic acid, suberic acid, succinic acid, tetradecanoic acid, undecanoic acid, etc. are used.

In the case of (C), the polyenes include vinylcyclohexene, cyclohexane oxide, epoxidized soybean oil, butadiene, polybutadiene, polybutadiene oxide,
1,5-hexadiene oxide and the like are used.

Oxidation of these polyenes is carried out with organic fatty acids such as acetic acid, propionic acid, butyric acid, or ozone.

Specifically, the epoxy resin shown above is l-vinyl-3
-Cyclohexene diepoxide, dicyclopentadiene diepoxide, 1,5-hexadiene diepoxide, 1,7-octadiene diepoxide, bis(3,
4-epoxycyclohexylmethyl oxalate), bis(3,4-epoxycyclohexylmethylpimarate), 3,4-epoxy-5-methylcyclohexylmethyl-3,4-epoxy-5-methylcyclohexanecarboxylate, ethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, butanediol diglycidyl ether, hexanediol diglycidyl ether, cyclohexanediol glycidyl ether, hexahydroxylylene diol diglycidyl ether, bisphenol-A-diglycidyl ether, p-p-dihydroxydif enyl ether dilycidyl ether, diglycidyl aniline, ethyl diglycidyl phosphate, decanediol diglycidyl ether, diethylene glycol diglycidyl ether, triethylene glycol diglycidyl ether, 1,4-
Bisbutane dicarbamate diglycidyl ether, sebacate diglycidyl ether, N-N-diglycidyl-p-methoxyaniline, diglycidylbutylamine, diglycidyl ethylene urea, xylylene diol diglycidyl ether, dihydroxydiphenyl sulfone diglycidyl ether, p (β・β′-dihydroxyethoxy)benzene diglycidyl ether, adipic acid diglycidyl ether, diglycidylaniline, diglycidylalanine, ethylene oxide diglycidyl ether, basic acids such as azelaic acid, 2,4-benzophenone -Dicarboxylic acid, brassylic acid, 1,4-cyclohexanedicarboxylic acid, fumaric acid, glutaric acid, α-
Ketoglutaric acid, itaconic acid, maleic acid, malonic acid,
Examples include diglycidyl ethers such as octadecylmalonic acid, pimelic acid, phthalic acid, isophthalic acid, terephthalic acid, suberic acid, succinic acid, tetradecanoic acid, and undecanoic acid.

Regarding these compounds, for example, JP-A-48-792
No. 98, No. 48-79299, U.S. Patent No. 246717
No. 1, No. 2506486, No. 2538072, No. 2
No. 581 464, No. 2615007, No. 26400
No. 37, No. 2716123, No. 2841595, No. 2866767, No. 2750395, No. 28901
No. 94, No. 3030336, No. 3053855, No. 3075999, No. 3173971, No. 35622
No. 75, No. 3620983, No. 3746545, etc., Cohen. J. Am. Chem. Soc. , 75
1733 (1952), Iwakura Makrom
ol. Chem. 104 66 (1967), “Ep.
Oxy Resin Technology” Inte
rscience. John Wiley & Sons
Among these compounds, diepoxides and diglycidyl compounds of .alpha..omega.-diolefin are particularly advantageous in view of their reactivity and ease of availability.

Furthermore, since the above-mentioned epoxy resin has an addition-polymerizable monovalent substituent, it may be used as a copolymer with other addition-polymerizable monomers.

Addition polymerizable monomers include styrene, butadiene, isoprene, acrylonitrile, methacrylonitrile,
These include acrylate, methyl acrylate, methacrylate, methyl methacrylate, and ethyl methacrylate.

Particularly preferred combinations among these are styrene-butadiene-glycidyl acrylate, styrene-butadiene-glycidyl methacrylate, styrene-butadiene-allyl glycidyl ether, styrene-butadiene-vinyl glycidyl ether, styrene-isoprene-glycidyl acrylate, and styrene-isoprene. -glycidyl methacrylate, methyl methacrylate-butadiene-glycidyl acrylate, methyl acrylate-butadiene-glycidyl methacrylate, etc., but this description is not intended to limit the scope.

The above epoxy resins (A), (B) and (C) have an epoxy equivalent of about 150 to 4000, preferably 400 to 1.
000 and an average molecular weight of approximately 100 to 4,000, preferably 400 to 1,400, which are effective in the present invention.

In addition, liquid resin is more compatible than solid resin because it has higher reactivity.

Many types of these epoxy resins are commercially available.
For example, Dow Epoxy DER321, DER33
2, DER335, DER336, DER341, DE
R431, DER438, DER434, DER732
, DER736, DER741 (above, Dow Che
mical Co,), ARALDITE538, G
Y250, GY0252, GY257, GY260, G
Y280, PZ820, 6600, 6700 (and above, C
ibaGeigy A,G. ), EPON (EPIK)
OTE) 152, 154, 828, 834, 836, 1
001, 1004, 1007, 1009 (She
ll Oil Co. ), EP201, EP206,
EP207 (Union Carbide Co
rp. It is convenient to obtain.

In the present invention, the polyamide resin is a bonding polymer having an acid amide bond (-CONH-) in the main chain, and the following (
It is a resin having repeating units of general formulas [■], [■] and [IV] synthesized by three methods: D), (E) and (F).

(D) Condensation of diamine and dicarboxylic acid: (E) Condensation of amino acids: (F) Ring opening of lactam: In the above formulas (D) to (F), R5, R6 and R8 are divalent with 1 to 20 carbon atoms. Group: R7 is 2 with 1 to 10 carbon atoms
Indicates a valence group.

R5 is preferably alkylene or alkenylene having 1 to 20 carbon atoms, cyclohexanediyl, phenylene, tolylene, xylylene, naphthylene, biphenylylene, and the like.

R6 is preferably alkylene or alkenylene having 1 to 20 carbon atoms, cyclohexanediyl, phenylene, tolylene, xylylene, naphthylene, biphenylylene, and the like.

R7 is alkylene having 1 to 10 carbon atoms, or alkylene having 1 to 10 carbon atoms;
Preferred are 100 carboxyl-substituted alkylene, phenyl-substituted alkylene having 1 to 10 carbon atoms, and the like.

R8 is preferably alkylene having 1 to 20 carbon atoms.

Further, the dicarboxylic acid of the formula (D) may be an anhydride, an ester, etc., and the amino acid of the formula (E) may be an anhydride.

Diamines of formula (D) include methylene diamine, dimethylene diamine, trimethylene diamine, tetramethylene diamine, pentamethylene diamine, pentamethylene diamine, hexamethylene diamine, heptamethylene diamine, octamethylene diamine, nonamethylene diamine, decamethylene diamine, piperazine, diaminocyclohexane, aminocyclohexyl)methane, bisf4
-amino-1,2-methylcyclohexyl)methane, o
-phenylenediamine, m-phenylenediamine, p-
phenylenediamine, 4,4'-diaminobiphenyl,
Tolylene diamine, xylylene diamine, naphthylene diamine, etc. Dicarboxylic acids include malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, succinic acid, azelaic acid, sebacic acid, nonanedicarboxylic acid, decanedicarboxylic acid, undecane Dicarboxylic acid, dodecanedicarboxylic acid, hexadecanedicarboxylic acid, tapsiaic acid, Japanese acid, maleic acid, fumaric acid, citraconic acid, diglycolic acid, malic acid, citric acid, phthalic acid, isophthalic acid, terephthalic acid, maleic anhydride, anhydride Phthalic acid etc. are used.

The amino acid (aminocarboxylic acid) of formula (E) is α-
Aminoacetic acid, L-α-aminopropionic acid, L-α-aminoisovaleric acid, ε-aminocaproic acid, L-α-
Aminoisocaproic acid, L-α-amino-β-phenylpropionic acid, L-aminosuccinic acid (aspartic acid)
, L-α-aminoglutaric acid (glutamic acid), γ-
Aminobutyric acid, α-amino-n-adipic acid, 11-aminoundecanoic acid, α-amino-DL-isoamyl acetic acid,
α-amino-n-butyric acid, 2-amino-2-methylbutyric acid,
α-aminocapric acid, α-aminocapric acid, 1-
Aminocyclohexanecarboxylic acid, α-aminocyclohexyl acetic acid, 1-amino-α-methylcyclohexanecarboxylic acid, ethyl aminomalonate, β-benzyl-L-
Asprate, β-benzyl-D-aspartate,
γ-benzyl-DL-glutamate and the like are used.

Lactams of formula (F) include glycine anhydride, α-pyrrolidone, α-piperidone, γ-butyrolactam, δ-
Valerolactam, ε-caprolactam, α-methylcaprolactam, β-methylcaprolactam, γ-methylcaprolactam, δ-methylglolactam, ε-methylcaprolactam, N-methylcaprolactam, β・r-
dimethyl glolactam, gamma-ethyl caprolactam,
γ-isoprobyl caprolactam, ε-isoprobyl caprolactam, r-butylcaprolactam, ε-enantholactam, ω-enantholactam, η-cabryl lactam, ω-cabryl lactam, ω-laurolactam, etc. are used.

These polyamides are commonly called nylons.

Specifically, nylon 2 is produced by polymerization of N-carboxyamino acid anhydride, nylon 3 is produced by polymerization of β-aminopivalic acid, nylon 4 is produced by ring-opening polymerization of α-pyrrolidone, and α
- Nylon 5 by ring-opening polymerization of piperidone, nylon 6 by ring-opening polymerization of ε-capulactam, nylon 7 by polymerization of ω-aminoenanthate, nylon 8 by ring-opening polymerization of cabrillolactam, ω-aminozonil acid. nylon 9, nylon 10 by ring-opening polymerization of caprinlactam, nylon 11 from 11-aminoundecanoic acid,
Examples include nylon 12 produced by ring-opening polymerization of ω-laurolactam, nylon 66 produced by condensation polymerization of hexamethylene diamine and adipic acid, and nylon 610 produced by condensation polymerization of hexamethylene diamine and sebacic acid.

Also, copolymers of these nylons, such as nylon 6
/66/610 (copolymerization ratio: 10/40/50), nylon 66/610 (specific polymerization ratio: 45/55), etc. can also be used.3 Among the above polyamide resins, those that are particularly effective in the present invention are epoxy resin curing. It is easy to react, and the following general formula [■] is created by increasing the amount of dicarboxylic acid and leaving a carboxyl group at the end.
VI] (n is the degree of polymerization R5 and R6 are the same as in (n) above)
Polyamide resin.

OH(OC-R5-CONH-R6-NH)nH[VI
] Furthermore, copolymers of these nylons and other monomers can also be used.

Specifically, graft copolymers with vinyl monomers such as 2-methyl-5-vinylpyridine, styrene, methyl methacrylate, sodium acrylate, vinyl acetate, vinylidene chloride, acrylonitrile; ethylene oxide, propylene oxide, ethyleneimine, cyclo With ring-opening polymerizable monomers such as oxbutane, ε-cabrolactam, ethylene sulfide, evichlorohydrin, maleic anhydride, phthalic anhydride, hexahydrophthalic anhydride, dichloromaleic anhydride, and dodecylsuccinic anhydride. copolymers, etc.

These can be carried out using conventional methods such as graft polymerization, acylation,
It can be made into a copolymer by alkylation or the like.

The molecular weight of these polyamide resins is 500 to 10,000
, preferably about 800 to 7000.

The amine equivalent is about 2 to 400. Product names are Amiran CM1031 (Toray KK.), Ube Nylon E
A1030 (Ube Industries K.K.), Grillon A1050
(Unitika K.K.), Plaskon 8211, 8
229 (Allied Chemical Corp.)
, Spencer Nylon 607 (Spence
r Chemical Co. , Ltd. ), Fost
er Nylon BK40F, BK40T (Fost
er Grant Co. , Lta. ), Ultra
idBKR1144/3 (BASF A.G.), Du
rethan BK50F, BK64F (Bayer
A. G. ), Maranyl F160, Fl70 (I
CILtd. ) etc. Nylon 6: Amiran CM302
1 (Toray K.K.), Zytel42 (E.I.Du
Pont de Nemours & Co. ), Ultra
amidAKR1183 (BASF A.G.), Ma
ranylA150M, A100E (ICI Ltd.
), Nylatron GS (Polymer Cor
Nylon 66 such as p); Amiran CM2006 (Toray K.K.), Zyte 138 (E.I., Du Pon
t de Nemours & Co. ), Ultrami
d S4, 84K (BASFA.G.), Marany
Nylon 610 such as IB100 and B100C (ICILtd.) are known.

Other polyamide resins include Tohm
ide, Fuji Kasei K. K,), Hitamide (Hit
amide, Hitachi Chemical K. K,), Versamide (V
arsamide, General Mills I
nc. ) etc. are known.

Regarding these polyamide resins, see Osamu Fukumoto (ed.), Plastic Materials Course (16), "Polyamide Resin", July 25, 1970, published by Nikkan Kogyo Shimbun: Murahashi, Imoto, Tani (eds.), "Synthetic Polymer V" 11- 186 pages, June 1, 1971
5th, published by Asakura Shoten: US Patent No. 21.30497; 2
130523: 2149273; 2158064; 2223493; 2249627: 2534347; 2540352: 2715620; 2756221; 2939862; 2994693: 3012994; 3133956; No. 3188228; No. 3193475; No. 3193483; No. 3197443 ; No. 3226362; No. 3242134; No. 3247167; No. 3299009; No. 3328352; No. 3354123.

Moreover, it is synthesized by a method similar to that of the above-mentioned polyamide resin.

Polyamideimide resins can also be used. Polyamide-imide resin is produced by the reaction of a low-molecular-weight polyamide with an amine group at the end, and an acid anhydride.The method involves the reaction of a low-molecular-weight polyamic acid with an amine group at the end with dibasic chloride; trimellitic acid derivative and a diamine.

Acid anhydrides or derivatives thereof include pyromellitic anhydride, pyromellitic acid-1,4-dimethyl ester, pyromellitic acid tetramethyl ester, pyromellitic acid ethyl ester, 2,3,6,7-naphthalenetetracarboxylic acid Acid dianhydride, 3,3',4,4'-biphenyltetracarboxylic dianhydride, 1,2,5,6-naphthalenetetracarboxylic dianhydride, 2,2',3,3'- Biphenyltetracarboxylic dianhydride, 2./.6.6'-biphenyltetracarboxylic dianhydride, etc. As the diamines, the above-mentioned aromatic diamines are used.

Examples of solvents for synthesis of polyamic acid include dimethylformamide, dimethylacetamide, dimethylmethoxyacetamide, N-methyl glolactam, dimethylsulfone,
Tetramethylene sulfone, N-acetyl-2-pyrrolidone, etc. are used.

Regarding the above polyamideimide, G.M. Bower
et al “Journal of Polymer
Science,” A-1, page 3135 (published in 1903): US Patent No. 2421024: British Patent No. 57085
No. 8; French Patent No. 386617: Belgian Patent No. 65
It is described in No. 0979, etc.

The mixing ratio of the cellulose derivative, epoxy resin, and polyamide resin used in the protective layer of the present invention described above is approximately 20/80 to 80/20 (weight ratio of the epoxy resin and polyamide resin), preferably 4
The mixing ratio of the epoxy resin and the polyamide resin is such that the epoxy content of the epoxy resin and the amine content of the polyamide resin are about 10/90 to 90/10, preferably 40/60 to 90/10. It is better to

If the amount of the cellulose derivative is too large, the adhesion with the magnetic layer will generally deteriorate, possibly resulting in pinholes, uneven coating, etc., which is not preferable.

Also, if the amount of epoxy resin and polyamide resin is too large, when making magnetic cards, the protective film is applied to a glossy plate (mirror-finished press plate, such as a stainless steel plate or a hard chrome plated plate) during processes such as hot pressing.

) sticks due to heat, which is undesirable.

Moreover, if the epoxy resin and polyamide resin are too large, the pot life in the coating liquid state will be shortened, which is not preferable.

The standard ratio of epoxy equivalent to amine equivalent is 50/50, but the higher the epoxy equivalent, the harder the protective film will be, which is less likely to be scratched and has excellent durability.

The effective thickness of the protective film is approximately 0.1 μm to 8 μm, but the range used is 0.5 μm to 4 μm, and the preferred range is 1.5 μm to 3 μm.

If the thickness is thin, it will be advantageous in terms of reproduction output, but it will not be able to function as a protective film and will be weak in terms of durability.

It is well known from the principles of magnetic recording that if the thickness of the protective film is too large, the gap loss naturally increases.

The magnetic recording material of the present invention comprises coating a magnetic layer on a non-magnetic support,
Either the normal process of drying, applying a protective layer thereon and drying, or the transfer-type process using a temporary support may be used, but the latter seems to be preferable. .

In the case of a transfer type, as shown in FIG. 1, a protective layer 2 is coated on a temporary support 1 and dried, and then a magnetic layer 3 is coated thereon and dried.

This manufacturing method involves a step of transferring the magnetic layer 3 and protective layer 2 onto a permanent support 4 by heating, pressing, or using an adhesive.

FIG. 2 shows the layer structure of the manufactured transfer type magnetic recording body.

By using the above-mentioned transfer type process, it is possible to prevent the drawbacks that the surface of the magnetic layer swells and dissolves due to the coating solvent of the protective layer in the normal process, resulting in deterioration of surface properties and deterioration of magnetic properties. This also eliminates the trouble of selecting a coating solvent.

In the case of magnetic tapes, magnetic sheets, magnetic disks, etc., they are shredded or cut after transfer, but in cases where the magnetic layer does not need to cover the entire surface of the permanent support, such as with magnetic cards, the state shown in Figure 1 before transfer is used. The magnetic layer and protective layer are transferred only to the required locations on the permanent support.

FIG. 3 shows the transfer process when manufacturing a magnetic card, and shows the case where the permanent support has a multilayer structure.

The permanent support is made by stacking a hard vinyl chloride sheet 5 and a vinyl chloride core sheet 6, and when these are stacked and the magnetic layer 3 and protective layer 2 are transferred, heat, pressure, or an adhesive is applied at the same time. Molded by.

The protective layer of the present invention may contain the lubricant, abrasive, and antistatic agent that are added to the magnetic layer, and may also contain a dispersant for dispersing these additives.

Dispersants include caprylic acid, capric acid, lauric acid,
Fatty acids with 12 to 18 carbon atoms (R1COOH
, R1 is an alkyl group having 11 to 17 carbon atoms); metal soaps made of alkali metals (Li, Na, K, etc.) or alkali metals (Mg, Ca, Ba) of the above-mentioned fatty acids: lecithin, etc. are used. Ru.

In addition, higher alcohols having 12 or more carbon atoms and sulfuric esters may also be used.

These dispersants are used in an amount of 1 to 20 parts by weight per 100 parts by weight of the binder.
It is added in a range of parts by weight.

Examples include Special Publication No. 39-28369, No. 44-17
No. 945, No. 48-15001, U.S. Patent No. 33879
No. 93: Described in No. 3470021, etc.

As a lubricant, silicone oil, carbon flux, graphite, carbon black graft polymer, molybdenum disulfide, tungsten disulfide, carbon number 12-16
fatty acid esters consisting of a monobasic fatty acid and a monohydric alcohol with 3 to 12 carbon atoms, a monobasic fatty acid with 17 or more carbon atoms, and a total of 2 carbon atoms in the fatty acid.
Fatty acid esters consisting of 1 to 23 monohydric alcohols can be used.

These lubricants are used in amounts of 0.2 to 100 parts by weight of binder.
It is added in an amount of 20 parts by weight.

Regarding these, the specifications of Japanese Patent Publication No. 43-23889, Japanese Patent Application No. 42-28647, Japanese Patent Application No. 43-81543, U.S. Patent No. 3470021: No. 3492235
No. 3497411; No. 3523086: 36
No. 25760: No. 3630772; No. 3634253
No. 3642539; No. 3687725; “IB
M Technical Disclosure Bul
Letin” Vol. 9, No. 7, Page 779 (
December 1966): ““ELEKTRONIK” 1961, No. 12, P
age 380 etc.

Commonly used abrasive materials include fused alumina,
silicon carbide chromium oxide, corundum, artificial corundum,
Diamonds, synthetic diamonds, garnet, emery (main ingredients: corundum and magnetite), etc. are used.

These abrasives have an average particle diameter of 0.05 to 5 .mu.m, particularly preferably 0.1 to 2 .mu.m.

These abrasives are used in an amount of 7 to 20 parts by weight per 100 parts by weight of the binder.
It is added in a range of parts by weight.

Regarding these, Japanese Patent Application No. 48-26749, US Patent No. 3007807; US Patent No. 3041196, US Pat.
No. 93066: No. 3630910, No. 3687725
No.: British Patent No. 1145349; West German Patent (DT-
PS) No. 853211.

Graphite, carbon black,
Conductive powder such as conductive carbon black and carbon black graft polymer; Natural surfactants such as saponin; Nonionic surfactants such as alkylene oxide, glycerin, and glycidol; higher alkylamines, quaternary ammonium salts , pyridine and other heterocycles, cationic surfactants such as phosphonium or sulfonium; anionic surfactants containing acidic groups such as carboxylic acid, sulfonic acid, phosphoric acid, sulfuric acid ester groups, and phosphoric ester groups; amino acids, amino sulfones Acids, amphoteric activators such as sulfuric acid or phosphoric acid esters of amino alcohols, etc. are used.

Some examples of surfactant compounds that can be used as antistatic agents are disclosed in U.S. Pat.
No. 2288226, No. 2676122, No. 26
No. 76924, No. 2676975, No. 2691566
No. 2727860, No. 2730498, No. 27
No. 42379, No. 2739891, No. 3068101
No. 3158484, No. 3201253, No. 32
No. 10191, No. 3294540, No. 3415649
No. 3441413, No. 3442654, No. 34
No. 75174, No. 3545974, OLS No. 1942665, British Patent No. 1077317
No. 1198450, etc., "Synthesis of surfactants and their applications" by Ryohei Oda et al. (Maki Shoten 1964 edition);
A. W. "Surf S Active Agents" by Robert Bayley (Interscience Publications, Inc. 1958 edition); T.P. Books such as "Encyclopedia of Surf Active Agents, Volume 2" by Sisley (Chemical Publishing Company 1964 edition): "Surfactant Handbook" 6th edition (Sangyo Tosho Co., Ltd., December 20, 1964) It is described in.

These surfactants may be added alone or in combination.

These are used as antistatic agents, but are sometimes used for other purposes, such as dispersion, improving magnetic properties,
It may also be used to improve lubricity and as a coating aid.

Organic solvents used when applying the protective layer include: ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone, and cyclohexanone; alcohols such as methanol, ethanol, propanol, and butanol; methyl acetate, ethyl acetate, butyl acetate, and lactic acid. Ester systems such as ethyl and acetic acid glycol monoethyl ether; ether,
Glycol ethers such as glycol dimethyl ether, glycol monoethyl ether, and dioxane; Tars (aromatic hydrocarbons) such as benzene, toluene, and xylene; methylene chloride, ethylene chloride, carbon tetrachloride, chloroform, ethylene chlorohydrin, dioxane, etc. Chlorinated hydrocarbons such as chlorobenzene are used.

The protective layer of the present invention is coated on a temporary support with the above composition,
Obtained by drying.

Further, in order to improve the releasability between the temporary support and the protective layer during transfer, a release agent may be provided between the temporary support and the protective layer.

As a mold release agent, wax, silicone oil, silicone resin, fluorine oil, polymethacrylate ester or its copolymer, polycarbonate, cellulose derivatives (nitrocellulose, cellulose glopionate, cellulose acetate, cellulose acetate butyrate, etc.), etc. Resins are used, and tungsten disulfide, molybdenum disulfide, graphite, etc. may be mixed in these resins.

Examples of these are JP-A-47-30303 and JP-A-47-30303;
-30305 etc.

However, if these materials are added as a mold release agent to the protective layer of the present invention, there is no need to provide a mold release layer.

Further, when manufacturing a transfer type magnetic recording body, an adhesive layer may be provided in order to improve the adhesion of the magnetic layer.

The adhesive layer is provided on a temporary support, a protective layer, and a magnetic recording layer, and after transfer, the permanent support, adhesive layer, magnetic layer, and protective layer are laminated in this order.

As the adhesive, vinyl chloride vinyl acetate copolymer, ethylene vinyl acetate copolymer, acrylic acid ester acrylonitrile copolymer, methacrylic acid ester acrylonitrile copolymer, polyvinyl acetate, silica ester, etc. are used.

Examples of these are described in JP-A-47-28904, JP-A-47-30303, and the like.

Those skilled in the art can easily select any release agent and adhesive according to the type of thermosetting resin, thermoplastic resin, or anti-core resin that is the binder of the magnetic recording layer. .

Furthermore, the coating solvent for the mold release agent and adhesive can be the same as the organic solvent for the protective layer of the present invention, which can also be easily implemented by those skilled in the art.

As the temporary support, polyesters such as polyethylene terephthalate and polyethylene-2,6-naphthalate, polyolefins such as polypropylene, cellulose derivatives such as cellulose triacetate and cellulose diacetate, and plastics such as polycarbonate are used.

Regarding the manufacturing method of the magnetic paint used in the present invention, please refer to
-15, No. 39-26794, No. 43-186, 47-
No. 28043, No. 47-28045, No. 47-28046
No. 47-28048, No. 47-31445, 48-
No. 11162, No. 48-21331, No. 48-33683
No. 3, USSR Patent Specification No. 308033, and other publications.

The magnetic paints described in these documents mainly contain ferromagnetic powder, binder, and coating solvent, and may also contain additives such as dispersants and antistatic agents.

As the binder used in the present invention, conventionally known thermoplastic resins, thermosetting resins, reactive resins, and mixtures thereof are used.

The ferromagnetic fine powder used in the present invention is r-Fe2O
3. Co-containing r-Fe2O3, Fe3O4, Co-containing Fe3O4, bertolide compound of r-Fe203 and Fe3O4 (FeOx, 1.33<x<1.50), C
Bertolide compound of r-Fe2O3 and Fe3O4 containing o (FeOx, 1.33<x<1.50), CrO2
, Co-Ni-P alloy, Co-Ni-Fe alloy, Co-
Ni-Fe-B alloy, Fe-Ni-Zn alloy, Fe-M
n-Zn alloy, F6-Co-Ni-P alloy, Ni-Co
Known ferromagnetic fine powders such as alloys can be used, specifically,
Special Publication No. 44-14090, No. 45-18372, No. 47-22062, No. 47-22513, No. 46-
No. 28466, No. 46-38755, No. 47-428
No. 6, No. 47-12422, No. 47-17284,
No. 47-18509, No. 47-18573, No. 39
-10307, No. 48-39639, U.S. Patent No. 30
No. 26215: No. 3031341: No. 3100194
No.: No. 3242005: No. 3389014; British Patent No. 752659; No. 782762; No. 100732
No. 3; French Patent No. 1107654; West German Published Patent No. OLS 1281334, etc.

The particle size of these ferromagnetic fine powders is about 0.2 to 1 micron in length, and the length/width ratio is about 1/1 to 20/1.

As a thermoplastic resin, the softening temperature is 150°C or less, the average molecular weight is 10,000 to 200,000, and the degree of polymerization is about 200 to 2.
For example, vinyl chloride vinyl acetate copolymer, vinyl chloride vinylidene chloride copolymer, vinyl chloride acrylonitrile copolymer, acrylic acid ester acrylonitrile copolymer, acrylic acid ester vinylidene chloride copolymer, acrylic acid ester styrene copolymer,
Methacrylic acid ester acrylonitrile copolymer, methacrylic acid ester vinylidene chloride copolymer, methacrylic acid ester styrene copolymer, urethane elastomer,
Polyvinyl fluoride, vinylidene chloride acrylonitrile copolymer, butadiene acrylonitrile copolymer, polyamide resin polyvinyl butyral, cellulose derivatives (cellulose acetate butyrate, cellulose diacetate, cellulose triacetate, cellulose propionate, nitrocellulose, etc.) Copolymers, polyester resins, chlorovinyl ether acrylate copolymers, amine resins, various synthetic rubber-based thermoplastic resins, and mixtures thereof are used.

Examples of these resins are given in Japanese Patent Publication No. 37-6877, 39-
No. 12528, No. 39-19282, No. 40-5349, No. 40-20907, No. 41-9463, No. 41-14
No. 059, No. 41-16985, No. 42-6428, 4
No. 2-11621, No. 43-4623, No. 43-1520
No. 6, No. 44-2889, No. 44-17947, 44-
No. 18232, No. 45-14020, No. 45-14500
No., 47-18573, 47-22063, 47-
No. 22064, No. 47-22068, No. 47-22069
No. 47-22070, 48-27886, U.S. Patent No. 3144352; U.S. Patent No. 3419420: U.S. Patent No. 3499
No. 789: Described in No. 3713887.

The thermosetting resin or reactive resin has a molecular weight of 200,000 or less in the state of a coating liquid, and when heated after coating and drying, the molecular weight becomes infinite due to reactions such as condensation and addition.

Also, among these resins, those that do not soften or melt before the resin is thermally decomposed are preferred.

Specifically, examples include phenol resins, epoxy resins, polyurethane curable resins, urea resins, melamine resins, alkyd resins, silicone resins, acrylic reaction resins, mixtures of high molecular weight polyester resins and isocyanate prepolymers, and methacrylate copolymers. and diisocyanate prepolymers, mixtures of polyester polyols and polyisocyanates, urea formaldehyde resins, mixtures of low molecular weight glycols/high molecular weight diols/triphenylmethane triisocyanates, polyamine resins, and mixtures thereof.

Examples of these resins are given in Japanese Patent Publication No. 39-8103, 40-
No. 9779, No. 41-7192, No. 41-8016, 4
1-14275, 42-18179, 43-120
No. 81, No. 44-28023, No. 45-14501, 4
5-24902, 46-13103, 47-220
No. 65, No. 47-22066, No. 47-22067, 4
No. 7-22072, No. 47-22073, No. 47-280
No. 45, No. 47-28048, No. 47-28922, U.S. Patent No. 3144353: No. 3320090: No. 34
No. 37510; No. 3597273: No. 3781210
No. 3781211.

These binders may be used alone or in combination;
Other additives may be added.

The mixing ratio of the ferromagnetic powder and the binder is 10 to 400 parts by weight, preferably 30 to 200 parts by weight, per 100 parts by weight of the ferromagnetic powder.

In addition to the above-mentioned binder and ferromagnetic fine powder, the above-mentioned dispersant, antistatic agent, etc. may be added as additives to the magnetic recording layer.

To form the magnetic recording layer, the above-mentioned composition is dissolved in an organic solvent and applied as a coating solution onto the above-mentioned protective layer.

magnetic powder and the aforementioned binder, dispersant, antistatic agent,
The solvent and the like are kneaded to form a magnetic paint.

For kneading, the magnetic powder and each of the above-mentioned components are fed into a mixing machine either simultaneously or individually one after another.

For example, there is a method in which magnetic powder is first added to a solvent containing a dispersant and kneaded for a predetermined period of time, and then the remaining components are added and mixing is continued to obtain a magnetic paint.

Various types of kneading machines are used for cross-mixing and dispersion.

For example, two roll mill, three roll mill, pole mill,
These include pepple mill inderer dispersion machine, high speed stone mill, high speed impact mill, disper, kneader, high speed mixer, homogenizer, ultrasonic dispersion machine, etc.

The technology regarding kneading and dispersion is described by T. C.゜Paint Flow and Pigment Di by PATTON
spersion (1964, John hon Wil
(Published by Ey & Sons).

It is also described in US Pat. No. 2,581,414 and US Pat. No. 2,855,156.

Methods for applying the magnetic recording layer onto the protective layer include air doctor coating, blade coating, air knife coating, squeeze coating, impregnation coating, 1) gravure coating, kiss coating, cast coating,
Spray coating etc. can be used, and other methods are also possible, and detailed explanations of these methods are given in "Coating Engineering" published by Asakura Shoten, pages 253 to 277 (published on March 20, 1972). .

By such a method, the magnetic layer coated on the protective layer is optionally subjected to a treatment for orienting the magnetic powder in the layer, and then the formed magnetic layer is dried.

Further, after performing surface smoothing processing or cutting into a desired shape if necessary, the protective layer and magnetic layer are transferred to produce the magnetic recording body of the present invention.

In this case, the orientation magnetic field is approximately 500 to 20
00 Gauss, the drying temperature is about 50 to 100°C, and the drying time is about 3 to 10 minutes.

Methods for orienting magnetic powder are also described in the following patents:

For example, US Patent No. 1949840; US Pat. No. 2796359; US Pat.
No. 427; No. 39-28368: No. 40123624;
No. 40-23625: No. 41-13181; 48-13
No. 043: 48-3 97 22, etc.

The magnetic recording medium of the present invention is used as a recording medium after being transferred to a permanent support.

The permanent support to which the magnetic recording medium of the present invention is transferred may be polyesters such as polyethylene terephthalate and polyethylene-2,6-naphthalate, cellulose derivatives such as polyprolyacetate and cellulose diacetate, plastic sheets such as polycarbonate, or Film: In addition to resin plates such as vinyl chloride, polycarbonate, acrylonitrile, styrene, ABS resin, and polyester resin containing glass fiber, metal plates such as aluminum and copper plates, glass plates, etc. can also be used.

The thickness of this permanent support is approximately 3 to 100 μm in the case of a film or sheet, preferably 5 to 50 μm, approximately 0.5 to 10 mm in the case of a disk or card, and approximately 0.5 to 10 mm in the case of a drum. It has a cylindrical shape, and its shape is determined depending on the recorder used.

When the above-mentioned permanent support is in the form of a tape or sheet, the surface opposite to the side on which the magnetic layer is provided has a so-called backcoat for the purpose of preventing static electricity and preventing transfer of recorded signals.
may have been done.

Regarding the back coat, for example, US Patent No. 28044
No. 01, No. 3293066, No. 3617378, No. 3062676, No. 3734772, No. 34765
No. 96, No. 2643048, No. 2803556, No. 2887462, No. 2923642, No. 29974
No. 51, No. 3007892, No. 3041196, No. 3115420, No. 3166688, etc.

The transfer temperature during transfer by heating and pressure is approximately 60 to 180℃.
℃, preferably 110-150℃, the transfer thickness is about 5-150℃
50kg/cm2, preferably 10-30kg/cm2
It will be held in

Generally, the transfer processing time is about 3 to 30 minutes, preferably 5 to 30 minutes.
It is 15 minutes.

The effects and advantages of the present invention are shown below.

■ Magnetic recording media with excellent wear resistance can be made.

■ First coat the protective film of the present invention on a temporary support,
A magnetic coating solution can be applied while still wet or after drying.

(2) The magnetic recording medium produced by the method (2) can have the magnetic layer transferred onto another permanent support, optionally via an adhesive.

In the method (2), the protective film is a release layer to improve peeling from the temporary support, and can function as a protective film as is after transfer to the permanent support.

(2) In a recording and reproducing system in which the magnetic recording layer and the magnetic head are in direct contact, demagnetization is extremely reduced when a fine particle Verdryde iron oxide magnetic material containing cobalt is used.

By adopting the method of ■■, magnetic recording layer transfer-type magnetic recording materials such as identification cards, magnetic keys, magnetic passbooks, magnetic slips, sales slips, parcel tags, tickets, commuter passes, cash dispenser cards, etc. etc. are particularly useful.

The present invention will be explained in more detail below using examples.

It will be readily understood by those skilled in the art that the components, proportions, order of operations, etc. shown herein may be modified without departing from the spirit of the invention.

Therefore, the invention should not be limited to the examples below.

In addition, in the following examples, all parts indicate parts by weight.

Example 1 [Protective layer coating liquid PC-1] Nitrocellulose (RS-1/2) 70 parts Epoxy resin (epoxy equivalent: 20 parts 470, average molecular weight: 900, reaction product of epichlorohydrin and bisphenol A) Polyamide resin (Amine equivalent: 10 parts 85, average molecular weight: 6000, condensation product of polymerizable fatty acid and ethylenediamine) Methyl ethyl ketone/xylene 1000 parts (773
weight ratio) mixed solvent [protective layer coating liquid PC-2] ethyl cellulose [ethoxy content: 55 parts 49%,
Viscosity of 5 wt% toluene/ethanol (8/20) solution (25 °C): 46 cps] Epoxy resin (epoxy equivalent: 35 parts 2400
, average molecular weight: 3700, reaction product of epichlorohydrin and bisphenol A) polyamide resin (amine consumption: 10 parts 300,
Average molecular weight: 1000, condensation product of polymerizable fatty acid and ethylenediamine) Methyl ethyl ketone/xylene 750 parts (7/3
Weight ratio) Mixed solvent [Protective layer coating liquid PC-3) Cellulose acetate butyrate 55 parts (butyryl content 37 wt.%, acetyl content 13 wt.%, hydroxyl group content in cellulose residue 2 wt.%) Epoxy resin ( Epoxy equivalent: 20 parts 350,
Average molecular weight: 200, reaction product of shrimp chlorohydrin bisphenol F) Polyamide resin (amine equivalent: 85, 25 parts Average molecular weight: 6000, condensation product of polymerizable fatty acid and ethylenediamine) Methyl ethyl ketone/xylene 750 parts (773
Weight ratio) mixed solvent [Protective layer coating liquid PC-4] Nitrocellulose (RS-172) 40 parts Epoxy resin (Epoxy equivalent: 35 parts 350, average molecular weight: 200, reaction product of epichlorohydrin and bisphenol A) Polyamide resin ( Amine equivalent: 25 parts 300,
Average molecular weight: 1000, condensation product of polymerizable fatty acid and ethylenediamine) Methyl ethyl ketone/xylene 500 parts (7/3
Weight ratio) Mixed solvent Each of the above protective layer coating solutions PC-1 to PC-4 was coated on a temporary support made of a polyethylene terephthalate film with a thickness of 20 μm by a doctor coating method to a dry thickness of 22 μm. , dried.

Samples 1 to 4 are used, respectively. [Magnetic coating liquid A] Co-containing magnetite (Co amount: 2 100 parts ato
mic%, HC: 6500e) Vinyl chloride vinyl acetate copolymer (25 parts polymerization ratio: 80/20 weight ratio, average degree of polymerization: 550) Lecithin 1 part dibutyl phthalate 5 parts butyl acetate/
Toluene (8/2 weight ratio: 230 parts) mixed solvent The above magnetic coating solution A, which was sufficiently kneaded and dispersed in a ball mill, on the protective layer of the above samples 1 to 4 was coated to a dry thickness of 13 μm.
It was applied and dried so that it became m.

The four types of wide sheets obtained were each slit into a width of 6.5 mm, and the magnetic layer and protective layer were transferred onto a hard vinyl chloride sheet having a thickness of 0.1 mm by heating at about 150° C. for 10 seconds.

This was laminated with a vinyl chloride core sheet with a thickness of 0.28 μm as shown in Fig.
It was heated and pressed at cm2, and then punched out into a standard size as an integral molding to obtain a cash dispenser card.

Samples 1 to 4 are used, respectively.

On the other hand, sample 5 is a comparative cash dispenser card obtained in the same manner as samples 1 to 4 above, by directly applying magnetic coating liquid A onto the polyethylene terephthalate film without using the protective layer coating liquid.

The abrasion resistance and demagnetization resistance of these samples 1 to 5 were measured using a magnetic card recorder, and the results are shown in Table 1.

(Cf, 1): The magnetic head of a wear-resistant magnetic card recorder is used as a mock head,
The surface condition of each sample was compared after repeating 1000 head passes back and forth at a head pressure of 280 g.

This is to check the state of damage on the surface, and if it has good abrasion resistance, it will not only not cause a decrease in the sensitivity of the signal signal recorded at the beginning, but also show that the magnetic layer has very few scratches and is in good condition. If the magnetic layer has poor reaction abrasion resistance, the magnetic layer will be scratched to the extent that the sensitivity of the initially recorded signal is reduced or the output waveform is disturbed.

In severe cases, not only the protective layer but also the magnetic layer can come off.

(Cf.2): Resistance to demagnetization The decrease in sensitivity after repeating 1000 round-trip head passes in the same manner as above is shown in dB.

Samples for comparison are estimated values.

Demagnetization includes heating and demagnetization due to the heat generated when a magnetic material containing Co contacts and slides on the head, and the magnetic layer itself peeling off due to the protective layer and magnetic layer having poor wear resistance. There are some that demagnetize due to demagnetization, and the sensitivity of all of them is lower than the initial sensitivity after testing with a test machine.

Example 2 The protective layer coating solution P of Example 1 was applied onto a temporary support of polyethylene-2,6-naphthalate film having a thickness of 20 μm.
C-2 was applied by a doctor coating method to a dry thickness of 2.5 μm and dried.

The following magnetic coating liquid B was sufficiently kneaded and dispersed in a ball mill, and the coating was applied to a dry thickness of 13 μm and dried.

[Magnetic coating liquid B]

Co-containing magnetite (Co amount: 2 100 parts atom
ic%, Hc: 6500e) Vinyl chloride vinylidene chloride copolymer 25 parts (Copolymerization ratio: 80/20 weight ratio, average degree of polymerization 350) Lecithin 1 part Dibutyl phthalate 5 parts Butyl acetate/toluene (8/2 weight 250 parts Ratio) Mixed solvent The obtained wide sheet was slit into 6.5 mm width, and the same process as in Example 1 was performed to obtain a cash dispenser card.

Let's call it sample 6.

Magnetic coating solution B was directly coated on a temporary support of polyethylene-2.6-naphthalate film having a thickness of 20 μm without providing a protective layer to a dry thickness of 13 μm, and dried.

The obtained wide sheet was slit to a width of 6.5 mm, and the same process as in Example 1 was performed to obtain a cash dispenser card.

Let's call it sample 7.

Methyl methacrylate was coated on a temporary support of polyethylene-2,6-naphthalate film with a thickness of 20 μm using acetone as a solvent to a dry thickness of 1.2 μm, dried, and then a protective layer coating solution was applied on top of this. PC-2 was applied to a dry thickness of 1.2 μm and dried.

Magnetic coating liquid B was applied onto this to a dry thickness of 14 μm, and dried. The obtained wide sheet was slit into a width of 6.5 μm, and a cash dispenser card was obtained by the same process as in Example 1.

Let's call it sample 8. Tests similar to those in Example 1 were conducted and the results are shown in Table 2.

(cf. 3): Perhaps because methyl methacrylate has a small surface hardness, the disturbance in the output waveform became abnormally large after about 600 cycles, and it could not be said that it had good wear resistance.

The above Examples 1 and 2 mainly evaluate the effect of the protective film on cards for cash dispensers.
, 6 (invention) and samples 5, 7, and 8 (for comparison).

A cash dispenser card provided with a protective layer according to the present invention was equipped with a mock head, and the head pressure was set at 280 g.

Durability lasts up to 1000 times in a card testing machine, and
While they showed good wear resistance and demagnetization resistance, all of the comparative examples showed poor running performance after running 280 to 350 times and stopped after running 330 to 450 times. It's gone.

In addition, in sample 8, the output waveform became abnormally large after about 600 cycles, and it was confirmed that the wear resistance was not sufficient.

It has thus been found that in the case of the protective layer of the present invention, the cellulose derivative, epoxy resin, and polyamide compound interact subtly and effectively to form an extremely excellent protective film.

Example 3 The following undercoat liquid was applied onto a polyamide film having a thickness of 20 μm to a dry thickness of 0.7 μm and dried (for the undercoat layer, see Japanese Patent Publication No. 22071/1983).

Amorphous polyester (90 parts terephthalic acid, ethylene glycol, triethylene glycol terpolymer, softening point 65°C) Polycarbonate 10 parts Methylene chloride 2000 parts The following magnetic coating liquid C was applied on the above polyamide film provided with the undercoat film. After thorough kneading and dispersion in a ball mill, the dry thickness is 11.
It was coated and dried to a thickness of μm.

[Magnetic coating liquid C]

Co-containing magnetite (Co amount: 2 100 parts atom
ic%, Hc: 6500e) Vinyl chloride vinyl acetate copolymer (copolymerization ratio: 11 parts)
87/13wt. %) Epoxy resin (Epoxy equivalent: 13 parts 470,
Average molecular weight: 900, reaction product of shrimp chlorohydrin and bisphenol A) Polyamide resin (amine value: 300, 5 parts Average molecular weight: 1000, condensation product of adipic acid and ethylenediamine) Carbon black 12 parts Lecithin
3 parts chromium sesquioxide 4 parts (Cr2O3, average particle size:
0.4 μm) Methyl isobutyl ketone/methyl ether 260 parts methyl ketone (1/1 weight ratio) mixed solvent Coat the protective layer coating solution PC of Example 1 on this wide magnetic film.
-1 to a dry thickness of 2 μm, and after drying,
A circular cutout with a diameter of 230 mm was made into a magnetic sheet.

This will be referred to as sample 9.

Sample 10 is a magnetic sheet obtained in Sample 9 without providing protective layer coating liquid PC-1.

The abrasion resistance and demagnetization resistance of the above two types of samples (magnetic sheets for memory) were measured using a magnetic sheet recorder, and the results are shown in Table 3.

(cf.4): 500 hours (25℃, 6℃) using a wear-resistant magnetic sheet recorder.
The surface condition of each sample after continuous use at 0% RH) was compared.

(cf.5): Demagnetization resistance Similarly to the above, the decrease in sensitivity after 500 hours is shown in dB.

The comparison sample became unmeasurable.

Example 4 A magnetic sheet was manufactured in the same process as in Example 3 using protective layer coating liquid PC-3.

Let's call it sample 11.

In Sample 11, a magnetic sheet was manufactured in the same manner as in Example 3 except that the following protective layer coating liquid was used instead of the protective layer coating liquid PC-3.

Let's call it sample 12.

Cellulose acetate butyrate 55 parts (butyryl content 37 wt.%, acetyl content 13 wt.%, hydroxyl group content in cellulose residue 2 wt.%) Epoxy resin (epoxy equivalent: 20 parts 350,
Average molecular weight: 200, reaction product of epichlorohydrin bisphenol F) Methyl ethyl ketone/xylene 560 parts (7/3
Weight ratio) Mixed solvent The abrasion resistance and demagnetization resistance of the above two types of samples were measured in the same manner as in Example 3, and the results are shown in Table 4.

(cf, 4), (cf. 5): Same as Table 3 In Examples 3 and 4 above, a protective layer was provided on the memory magnetic sheet as the magnetic sheet, but Samples 9 and 11
Comparing Samples 10 and 12 (for comparison) with Samples 10 and 12 (for comparison), it can be seen that they are extremely excellent in terms of durability.

In other words, the samples provided with the protective layer according to the embodiments of the present invention (Samples 9 and 11) not only have durability for 500 hours, but also have a decrease in output of -0.8 to -1 after 500 hours.
．． 9dB, and one without a protective layer takes 8 hours to play (sample 10), and one lacking one of the three components wears off within a few minutes (within 2 minutes) and becomes unplayable. (Sample 12).

From the above results, it is clear that the protective film needs to contain at least three components: a cellulose derivative, an epoxy resin, and a polyamide resin.

Examples 1 to 4 show some examples of the present invention, but if it essentially contains the above three components, it can be used as a fourth component with a content within 15% of the total binder. It has also been found that other resins can be mixed in, if any, and the results do not change in any way.

Furthermore, in Examples 1 and 2, examples were shown for cash tape dispenser cards, and in Examples 3 and 4, examples for magnetic sheets were shown, and in both cases, it was recognized that the effect as a protective layer was good. Since the protective layer of the invention is cured to form a hard coating film, it seems to be more effective when the support is hard, that is, when it is used as a magnetic card.

Furthermore, it has been found that the ferromagnetic fine powder to be used is preferably bertholed iron oxide, and particularly preferably bertholed iron oxide containing Co.

Example 5 The following undercoat liquid was applied onto a polyamide film having a thickness of 20 μm to a dry thickness of 0.7 μm and dried (see Japanese Patent Publication No. 47-22071 for the undercoat layer).

Amorphous polyester (90 parts terephthalic acid, ethylene glycol, triethylene glycol terpolymer, softening point 65°C) Polycarbonate 10 parts Methylene chloride 2000 parts The following magnetic coating solution D was applied on the above polyamide film with the undercoat layer. After thoroughly kneading and dispersing in a ball mill, the dry thickness is 11μ.
It was applied and dried so that it became m.

[Magnetic coating liquid D]

Co-containing magnetite (Co amount: 2 100 parts atom
ic%, Hc: 6500e) Nitrocellulose (RS-1/2) 11 parts Epoxy resin (epoxy equivalent: 13 parts 470, average molecular weight: 900, reaction product of shrimp chlorohydrin and bisphenol A) Polyamide resin (amine value : 300, 5 parts Average molecular weight: 1000, condensation product of adipic acid and ethylenediamine) Carbon black 12 parts Lecithin
3 parts chromium sesquioxide 4 parts (Cr2O3, average particle size:
0.4 μm Methyl isobutyl ketone/methyl ether 260 parts methyl ketone (1/1 weight ratio) mixed solvent On this wide magnetic film, the protective layer coating solution PC of Example 1 was applied.
-1 to a dry thickness of 2 μm, and after drying,
A circular cutout with a diameter of 230 mm was made into a magnetic sheet.

This will be referred to as sample 13.

Sample 14 is a magnetic sheet obtained in Sample 9 without applying protective layer coating liquid PC-1.

The abrasion resistance and demagnetization resistance of the above two types of samples (magnetic sheets for memory) were measured using a magnetic sheet recorder, and the results are shown in Table 5.

(cf.4): 500 hours (25℃, 6℃) using a wear-resistant magnetic sheet recorder.
The surface condition of each sample after continuous use at 0% RH) was compared.

(cf.5): Demagnetization resistance Similarly to the above, the decrease in sensitivity after 500 hours is shown in dB.

The comparison sample became unmeasurable.

As described above, when a combination of cellulose derivative, epoxy resin, and polyamide resin is used only in the magnetic layer (
There is a noticeable difference in the effects in abrasion resistance and deterioration resistance between sample 14) and when used as a protective layer (sample 13), indicating that it is particularly effective when used as a protective layer. .

The present invention includes the embodiments shown below.

(1) In the claims, the weight ratio of the cellulose derivative and (epoxy resin and polyamide resin) of the protective layer is about 20/80 to 80/20, and the epoxy consumption of the epoxy resin and the amine of the polyamide resin are A magnetic recording medium having an equivalent ratio of about 10/90 to 90/10.

(11) The magnetic recording material according to (I) above, wherein the degree of polymerization of the cellulose derivative is about 20 to 1000.

(iii) The magnetic recording material according to (i) above, wherein the epoxy resin has an epoxy weight of about 150 to 4,000 and an average molecular weight of about 100 to 4,000.

(iv) In the above (i), the amine equivalent of the polyamide resin is about 2 to 400, and the average molecular weight is about 500.
~10,000 magnetic recording medium.

(v) In (i) above, the dry thickness of the protective layer is approximately 0.1
A magnetic recording medium having a diameter of ~8 μm.

(vi) In the claims, a magnetic recording body is provided by coating a magnetic coating liquid containing ferromagnetic fine powder and a binder as main components on a non-magnetic support and drying it to form at least one magnetic recording layer; A magnetic recording material that is coated with a protective layer coating liquid mainly composed of cellulose derivatives, epoxy resins, and polyamide resins, and dried to provide a protective layer.

(vii) A magnetic recording body provided with an undercoat layer between the nonmagnetic support and the magnetic recording layer in the above (VD).

(viii) In (vi) above, the magnetic recording body is a magnetic sheet.

(ix) In the claims, a magnetic recording material is provided by coating a protective layer coating solution containing a cellulose derivative, an epoxy resin, and a polyamide resin as main components on a temporary non-magnetic support and drying it to form a protective layer. A magnetic coating solution containing ferromagnetic fine powder and a binder as main components is coated on top and dried to form at least one magnetic recording layer, and then the magnetic recording layer and protective layer are coated on the permanent support by heating and pressure. A magnetic recording medium that has been transferred to and provided on.

(x) In (ix) above, the magnetic recording medium is a magnetic card.

[Brief explanation of drawings]

FIG. 1 is an enlarged sectional view of the magnetic recording medium before transfer, and FIG. 2 is an enlarged cross-sectional view of the magnetic recording medium after transfer. 1 is a temporary support, 2 is a protective layer, 3 is a magnetic layer, and 4 is a permanent support. FIG. 3 shows one process when the protective layer of the present invention is used in a magnetic card, where 2 is the protective layer, 3 is the magnetic layer,
5 is a hard vinyl chloride sheet, and 6 is a vinyl chloride core sheet.

Claims (1)

[Claims] 1. A magnetic recording material having a magnetic layer mainly composed of ferromagnetic fine powder and a binder on a non-magnetic support, and further having a protective layer thereon, wherein the protective layer is made of a cellulose derivative, an epoxy resin, and a polyamide resin. A magnetic recording medium characterized by: