JPS5864631A - Magnetic recording medium - Google Patents

Abstract

PURPOSE:To enhance the lubricity and wear resistance by incorporating a specified carboxyl modified org. silicone compound and a higher fatty acid to a magnetic layer. CONSTITUTION:A carboxyl modified org. silicone compound represented by the general formula (where each of R1 and R2 is -CH3 or R3COOH, R3 is a 1-26C hydrocarbon group, n1 is a integer of 0-<1,000, n2 is an integer of 1-500 and n1+n2<=1,000) and a 10-30C higher fatty acid such as lauric acid, myristic acid, palmitic acid, stearic acid, oleic acid or linolic acid are incorporated to a magnetic layer using vinyl chloride-vinyl acetate resin or other binder. Said silicone compound has a hydrocarbon group having a carboxyl group with a great affinity for the binder in the principal chain, or it has such hydrocarbon groups in the principal chain and at both terminals of the principal chain.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a magnetic recording medium, and an object thereof is to improve the lubricity and wear resistance of a magnetic layer, and to provide a magnetic recording medium that has excellent running stability and durability. be.

In general, magnetic recording media such as magnetic tapes, which are made by coating a magnetic paint consisting of magnetic powder, binder, organic solvent, and other necessary components on a substrate such as a polyester film, do not come into contact with magnetic heads, guide members, etc. The magnetic layer must have a low coefficient of friction and excellent running stability, and since it comes into intense sliding contact with the magnetic head during recording and playback, the magnetic layer must have little wear and excellent durability. required.

For this reason, as a measure to improve the lubricity and wear resistance of the magnetic layer, lubricants such as higher fatty acids have been incorporated into the magnetic layer, and the inventors have already proposed the following general method. It was proposed that a carboxyl-modified organic silicone compound represented by formula (1) be contained in the magnetic layer.

(However, in the formula, R5 and R2H-CH, or -RC0
OH, R5 represents a hydrocarbon group having 1 to 26 carbon atoms, and n
, and n2 are 0≦n, < i 000, ]≦n2≦
500, an integer satisfying n1+n2≦1ooo. ) However, higher fatty acids have a good affinity with metals or their oxides, and are highly resistant to metals and society. Although it is possible to improve the wear resistance of the magnetic layer by sufficiently reducing the frictional resistance during sliding contact with the magnetic head made of oxide, it has no lubrication effect on rubber guide members such as pinch rollers. Carboxyl-modified organic silicone compounds have an excellent lubricating effect, especially on rubber guide members such as pinch rollers, but they are lubricating on metals and society. It is difficult to sufficiently improve the wear resistance of the magnetic layer because it does not have very good affinity and properties with magnetic heads made of 812 compounds, and it is not possible to sufficiently reduce the frictional resistance during sliding contact with the magnetic head. There is.

The inventors conducted detailed studies in view of the above circumstances and found that the general formula (wherein R5 and R2Ifi-CI (3 or -
R, COOH, and R represent hydrocarbon groups having 1 to 26 carbon atoms, and n and n are integers of 0≦n, <1000, 21≦12≦500, n, +n2≦1000. ) When the carboxyl-modified organosilicone compound represented by the formula and a fatty acid having 10 to 30 carbon atoms are contained in the magnetic layer, they act synergistically, making the pinch roller - made of Kotobuki's rubber - more effective than when each is used alone. The inventors have discovered that an even more excellent lubrication effect can be exerted on the guide member and the magnetic head made of metal or metal oxide, and that the lubricity and wear resistance of the magnetic layer can be sufficiently improved, leading to the invention. The carboxyl-modified organosilicone compound d used in this invention is a hydrocarbon having a carboxyl group in the main chain or at both ends of the main chain that has excellent affinity with the binder, as shown in the above general formula. Because it has a modified group similar to that of the present fatty acid, it has good compatibility with the binder and has excellent compatibility with the binder. <0 In addition, these hydrocarbon groups having carboxyl groups used in combination have lubricity, and together with the main chain consisting of an organic silicone compound with excellent lubricity, these hydrocarbon groups having carboxyl groups also have a lubricating effect. As a result, the lubricity and wear resistance of the magnetic layer are improved, and in particular, the organic silicone compound of this coffin exhibits an excellent lubrication effect on rubber guide members such as pinch rollers. and carbon number 1
When used in combination with a fatty acid of 0 to 30, the fatty acid exhibits an excellent lubricating effect, especially on magnetic spatula y made of metals or metal oxides. The lubricity and wear resistance of the magnetic layer are further improved by leaching out and acting synergistically. When the carboxyl-modified organosilicone compound mentioned above has a hydrocarbon group having a carboxyl group not only in the main chain but also at both ends of the main chain, these effects are remarkable.
Therefore, when a carboxyl-modified organosilicone compound and a fatty acid having 10 to 30 carbon atoms are used in combination, the lubrication effect on the rubber guide member and the metal magnetic head is sufficiently exhibited, and the lubricity and wear resistance of the magnetic layer are sufficiently improved. A magnetic recording medium with excellent running stability and durability can be obtained.

In the carboxyl-modified organosilicone compound of the present invention represented by the above general formula, R of the hydrocarbon group having a carboxyl group represented by -R5COOH is -(]←, -
Aromatic 5 such as (CH)-(]-
2 m compound or general formula CnHi+n or CnH2n-
The saturated or unsaturated hydrocarbon group represented by 2 preferably has 1 to 26 carbon atoms, and preferably has 1 to 26 carbon atoms.
If it is less than 26, the improvement in wear resistance will not be sufficient, and if it exceeds 26, the lubricity may deteriorate instead. As a specific example of a hydrocarbon group having such a carboxyl group, for example, C-2H4α loss H1-C, H6C0OH%-C
5H, oCOOH%-C,. H2oCOOH%-C,4
H28COOHN -C2oI(, oCOOH% -C
26H, cooii.

-C2H2COOH, -C,H,C0OH, -C,H,
C00II.

-C4゜H,,C00Hs -C4,H6C0OHz
-C,ol(,,C0OH.

-c26H5ocooL -C21(, -C6H,C0
Examples include 0HX-C6H, Ct)OH, and the like.

R4 and R2 are a methyl group or a hydrocarbon group having the same carboxyl group as mentioned above, and when this Ri and R2 are hydrocarbon groups having a carboxyl group, they can be used together with a binder and a fatty acid having 10 to 30 carbon atoms to be used together. The compatibility is further improved, and the lubricity and wear resistance of the magnetic layer are further improved. Note that R, and R, Fi thresholds may be different or different.
n, <1000.1≦n, ≦500, nl+H2≦10
The carboxyl-modified organosilicone compound of the present invention preferably has an integer of 00. If n and H2 are too large, it will dissolve in an organic solvent and become difficult to form into a paint. One type may be used alone, or two or more types may be used in combination.

The fatty acids used in combination preferably have 10 to 30 carbon atoms, such as lauric acid, myristic acid, palmitic acid, stearic acid, oleic acid, and linoleic acid. This type of fatty acid has very good compatibility with the binder and the above-mentioned carboxyl-modified organosilicone compound used in combination, and has an excellent lubricating effect especially on magnetic heads made of metals or metal oxides. When used in combination with an organic silicone compound, this lubricating effect is further improved, and the lubricating effect of the carboxyl-modified organic silicone compound, especially on rubber guide members, is further improved.
The lubricity and wear resistance of the magnetic layer are further improved.

The mixing ratio of the carboxyl-modified organic silicone compound and the fatty acid having 10 to 30 carbon atoms used together in this way is determined by the weight ratio (carboxyl-modified organic silicone compound to fat #
) is preferably within the range of 1:20 to 10:1; if the mixing ratio of the carboxyl-modified organic silicone compound is too small, the lubricating effect on the rubber guide member will not be sufficient, and running stability will not be sufficiently improved. If the mixing ratio of fatty acids is too low, the lubricating effect on the magnetic head will be insufficient and the wear resistance will not be sufficiently improved.

-1. For those who use both, the desired effect will be exhibited if the total amount of the magnetic powder is 0.1 times larger than that of the magnetic powder, and as the content increases, the desired effect will be achieved. However, if a 10-weight lubricant is introduced, these lubricants may leak excessively onto the surface of the magnetic layer, contaminating the magnetic head, etc., and reducing the output. Te 0
．． 1 to 0 weight g! It is preferable that the carboxyl-modified organic silicone compound and the fatty acid having 10 to 30 carbon atoms be contained in the magnetic layer within the range of 0%. This can be done by mixing and dispersing with a solvent, etc. to prepare a magnetic paint, applying this magnetic paint onto a substrate such as a polyester film, and drying it.
The solution obtained by dissolution may be applied or sprayed onto a previously formed magnetic layer, or conversely, the magnetic rflft may be immersed in the above solution.

As the magnetic powder used here, for example, r-Fe2
0. Powder, Fe, 0. Powder, powder, Co-containing - Fe205
Powder, Co-containing Fe, O, powder, CrO2 powder and other Fe
Various conventionally known magnetic powders such as powder, Co powder, and Fe-Ni powder are widely included. In addition, binders include vinyl chloride-vinyl acetate resin, vinylidene chloride resin, acrylonitrile-butadiene J tM, vinyl butyral resin, polyurethane resin, cellulose resin,
Any binder commonly used as a binder for magnetic powders, such as isocyanate compounds, can be used, and vinyl chloride-vinyl acetate resins, cellulose resins, polyurethane resins, and the like are preferably used.

The organic solvent is not particularly limited, and includes a solvent suitable for dissolving the carboxyl-modified organic silicone compound of the present invention, a fatty acid having 10 to 30 carbon atoms, and a binder, such as a ketone such as acetone, methyl isobutyl ketone, methyl ethyl ketone, and cyclohexanone. solvents, ester solvents such as ethyl acetate and butyl acetate, benzene,
Aromatic hydrogen-based solvents such as toluene and xylene, alcohol-based koji agents such as isopropyl alcohol, acid-based solvents such as dimethylformamide, and ether-based solvents such as tetrahydrofuran and dioxane may be used alone or in combination of two or more. used.

In addition, each packaging additive normally used in magnetic paint,
For example, a dispersant, an abrasive, an antistatic agent, etc. may be optionally added and used. Next, examples of the present invention will be described.

Example Using a carboxyl-modified organic silicone compound represented by the structural formula, r-Fe205 magnetic powder 80 overlapping parts VA
G) I (manufactured by U, C, C, USA, chloride 10 I
I vinyl-vinyl acetate-vinyl alcohol copolymer) Bandex T-5250 (Large 8 Urethane elastomer manufactured by Hon Ink Co.) Coronate Nippon Polyurethane 2 Trifunctional low molecular weight isocyanate compound manufactured by Kogyo Co., Ltd.) Laurin A magnetic paint was prepared by mixing and dispersing a mixture of the following compounds in a ball mill for 70 hours: 0.6 parts by weight of acid, 50 parts by weight of cyclohexanone, 50 parts by weight of methyl ethyl ketone, and 043 parts by weight of carboxyl-modified organic silicone. Comparative Example 1 In the composition of the magnetic paint in the example, laurin A magnetic tape was made in the same manner as in Example except that the acid was omitted.

Comparative Example 2 A magnetic tape was produced in the same manner as in the example except that the carboxyl-modified organic silicone compound was omitted from the composition of the magnetic paint in the example.

The magnetic tapes obtained in Examples and Comparative Examples were tested for durability, and the friction coefficient and output fluctuation were measured. The durability test was carried out under the conditions of 35°0,801RH, head load of 10g, and running speed of 4.8e+s/se.
Run with e and play, the output is 3 dB from the initial output.
The magnetic head and pinch ruler were measured after running the magnetic tape 200 times under the same conditions as the durability test described above.
The friction coefficient was measured. In addition, the output fluctuation was measured by running the magnetic tape under the same conditions as the durability test described above.
Measure the output fluctuation after running the VM.

The table below shows the results. As is obvious, the magnetic tape obtained by this invention (Example) is the same as the conventional magnetic tape (Comparative Examples 1 and 2).
Compared to K, the friction coefficient and output fluctuation are small and the durability is good. Therefore, the magnetic recording medium obtained by this invention has good lubricity and wear resistance of the magnetic layer, and has excellent running stability and durability. I know that there is.

Claims (1)

[Claims] 1. General formula (wherein R5 and R2t;!-C1,,t or-
R, C0OH, R, represents a hydrocarbon group having 1 to 26 carbon atoms, n and n2 digits 0≦n, ≦1000.1≦n2
It is an integer of ≦500 and ns+n2≦1000. ) A magnetic recording medium having a magnetic layer containing an organic silicone compound represented by the formula and a fatty acid having a carbon number lθ to 30