JPS5898837A - Magnetic recording medium - Google Patents

Abstract

PURPOSE:To enhance traveling stability and durability, by adding a specified organic silicone compd. into a magnetic layer. CONSTITUTION:A magnetic layer consisting mainly of a magnetic powder and a binder contains an org. cilicone compd. represented by the formula (R1, R2 are -CH3 or -R3NO2, R3 is 1-26C hydrocarbon group, and n1, n2 are each an integer shown as follows: 0<=n1<1,000, 1<=n2<500, n1+n2<=1,000) having polar groups represented by -R3NO2 superiod in compatibility with the binder, on the main chain or on the main chain and at both its ends.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a magnetic recording IAI body, and its object is 7) to improve the lubricity and IIF resistance of the magnetic layer, and to improve the magnetic constant and have excellent running stability and durability. J1 button 1Q
It is about providing a body.

Magnetic tape such as P-Ki tape, which is made by applying a crushable coating consisting of magnetic powder, binder, organic bath agent, and other necessary ingredients, on a substrate such as a polyester film. The body is required to be stable (because the friction coefficient of the silicon and outer layer is small because it runs while coming into contact with the F head, the guide part, etc.), and it is required to be stable during recording and playback. Since it comes into violent sliding contact with a magnetic head, etc., it is required that the magnetic property is low and the durability is low.

Therefore, the γ-slip property and uItp resistance of the magnetic layer are
Traditionally, it has been used as a force to improve sexuality.
11. What kind of oil is included in the layer? The general formula of <I
) or by mixing a silicone compound modified with a fatty acid shown in (lI) into the magnetic layer.41-
The plan is i.

(In the formula, R and R2 indicate the number of saturated or unsaturated carbon atoms having 7 to 21 carbon atoms, and the number of carbon atoms is 0 to 50.) OC horse (1μ, and R3 in the formula , R2 and R5 have 7 to 21 carbon atoms
saturated or slightly saturated hydrocarbon group, m is an integer of 1 to 100, n is an integer of O to 250, m -1-n≦30
0, m≧n/5. ) However, although silicone oil has excellent lubricity, it has poor compatibility with the binder, and as a result, the magnetic properties of silicone oil are inhomogeneous, resulting in pinholes, and the magnetic property of 1+i tends to ooze out excessively. , Also It]l! ! The fatty 17i acid-modified silicone compound represented by the general formula (Kuchiwayobi (II)) has a fatty acid-modified silicone compound that has tψ residues at both ends or both ends and in the main chain due to its affinity with binders. Because it has a group, it has good compatibility with binder, and the lubricating effect is exerted to lubricate the magnetic 11 layers 'P'1 and 1Ill-IIv.
Although much effort has been made, the results are still not fully satisfactory.

In view of the above circumstances, these inventors conducted a thorough examination M4 and found that the general formula (however, in the formula, R1 and R2 are replaced by d-R, N
O2 and R3 represent a hydrocarbon group having 1 to 26 carbon atoms, and n
l and n2 are 0≦n, <1000, ■≦02≦500
, n, is an integer of 10n2≦1000. ) When the modified organic silicone compound shown in It was discovered that the lubricity and cold resistance of the magnetic layer could be sufficiently improved, and the present invention was completed.

The modified 41s silicone material used in this invention has an upper grade of P-1! As shown in the formula, it has a hydrocarbon group with a nitro group that is polar, strong, and has excellent affinity for binders CC in the main chain and at both ends of the main chain. They are compatible with each other, therefore, they ooze out to the surface of the magnetic layer appropriately, and do not ooze out to the surface of the magnetic layer 7 or cause pinholes. In addition, the hydrocarbon side containing these highly polar nitro groups has good lubricity, and together with the main chain consisting of an organic silicone compound with excellent lubricity, these hydrocarbon groups containing nitro groups also have an excellent lubrication effect. As a result, the lubricity and wear resistance of the magnetic layer are further improved.

These effects are particularly noticeable when hydrocarbon groups having nitro groups are present not only in the middle of the main chain but also at both ends of the main chain. The lubricity and abrasion resistance of the magnetic layer are sufficiently improved without excessive exudation or formation of pinholes, resulting in a magnetic recording medium with excellent running stability and durability.

In the modified organosilicone compound of the present invention represented by the above general formula, a saturated or unsaturated hydrocarbon group represented by ~R3NO3 or represented by the general formula CnHzn or CnH2n-2, and the number of carbon atoms is in the range of 1 to 26. If the number of carbon atoms is less than 1, the resistance to W: K
If the number exceeds 26, the lubricity may not be improved sufficiently, and the lubricity may deteriorate on the contrary.

Specific examples of hydrocarbons having such a nitro group include, for example, C2H4N O2, C5H1oN O
2-C1oH2ONO2"26H52NO2, -C2H
, , NO2, etc.

R1 and R2 are a methyl group or a hydrocarbon hydrocarbon group having the same nitro group as described above, and when R1 and R2 are hydrocarbon groups having a nitro group, the compatibility with the binder is even better, and it is suitable. (The lubricity of the magnetic layer and the wear resistance of F-0: i4 are further improved.

R4 and R2 in 'f' may be the same or different.

1, the degree of polymerization, i.e. nl and n2&TF in the above general formula
o S nl< 10011.1≦02≦500, n
, +n2≦1000, preferably an integer, nl
If n2 is 1 or too large, it will dissolve in organic solvents, making it difficult to form into a paint, and the lubricity and wear resistance will not be sufficiently improved by V.

Such modified organic silicone compounds of the present invention may be used alone or in a mixture of two or more, and have a magnetic property of 0.1% by weight or more based on the magnetic powder. When contained in the layer, its AI effect is exhibited, and the content 11
The effect becomes more pronounced as the number increases. However, the content h
When 1% of the magnetic powder is introduced to the magnetic powder, excessive exudation occurs on the surface of the magnetic layer, so the magnetic powder is reduced to %1 and 0.
．． Is it contained in the magnetic layer within a range of 1 to 10% by market weight? It is preferable to

The organic silicone compound excluded from this invention can be used as a magnet.
K is contained in one layer by mixing and dispersing it with magnetic powder, binder, organic solvent, etc. to prepare a magnetic paint.
This magnetic paint can be applied to a substrate such as a polyester film, dried, and manipulated to produce a good magnetic coating.Also, the modified silicone compound of the present invention can be obtained by dissolving the modified silicone compound of the present invention in a suitable solvent. The solution may be coated or sprayed onto a pre-formed magnetic layer, or conversely, the magnetic layer may be immersed in the -1-,1 solution.

Here, as a magnetic powder with LI■, for example, r-Fe
20. Powder, Fe, 04 powder, Co-containing -Fe, 0.
Powder, CoA, I + Fe s Oa powder, Cr O
2 powder, Fe powder, CO powder, r' e -N i
Powders include a wide variety of conventionally known magnetic powders. In addition, as a binder (1, homogenized vinyl-vinyl resistant resin, acrylonitrile chloride resin, acrylonitrile), lyle-butadiene copolymer, vinyl butyral resin, polyurethane resin, cellulose resin, incyanate compound. Any of those commonly used as a binder for magnetic powder can be used, and among them, vinyl chloride-vinyl acetate copolymers, fiber resins, polyurethane resins, etc. are preferred.

The organic solvent is not particularly limited, and includes solvents suitable for dissolving the modified organosilicone composition and the binder of the present invention, such as acetone, methyl isobutyl ketone, methyl ethyl chloride, cyclohexanone, and other ketones. ester solvents such as ethyl acetate and butyl acetate, aromatic hydrocarbon solvents such as benzene, toluene, and xylene, alcohol solvents such as isopropyl alcohol, amide solvents such as dimethylformamide, tetrahydrofuran, dioxane, etc. Ether thread melting can be used alone or in combination with two glazes.
] Ru.

Oh, there's t' in the magnetic paint! Various additives commonly used in Tl, such as dispersants, abrasives, antistatic agents, etc., may be optionally added.

Next, embodiments of the invention will be described.

Example 1 Using a modified/ζ-shaped silicone compound expressed by the drawing formula 17, Co-containing T4' r -Fe 205 friable powder
80 heavy Ire part VAGFI (US j1) IJ, C, Ct
'l・:11'J, hi, tft' ] (17
/Vinyl-vinyl acetate vinyl aluminum, -J-ru combined foreign car combined Tex 1'-5250 (Ink: ilu!, urethane elastomer) Coronae) L f Japanese car urethane 2 〃
Industrial Nef III! A magnetic paint was prepared by mixing and dispersing a mixture consisting of the following compositions in a ball mill for 70 hours: .

This magnetic paint was applied to a polyester film 1-11μ thick.
I smoked 1! The magnetic tape was coated to a thickness of 5μ, dried, and subjected to surface treatment, and then cut to 3.8 mm rl to make a magnetic tape.

Example 2 In composition 1 of the magnetic paint in Example 1,
A magnetic tape was made in the same manner as in Example 1, except that the same amount of a modified organic silicone compound represented by the structural formula below was used in place of the modified organic silicone compound having the structural formula shown in Example 1. Ta.

Comparative Example 1 Composition of the magnetic paint in Example 1, 1r (wherein, in place of the modified organic silicone compound having the structural formula shown in Example 1, dimethylborisiloxy → non-type silicone represented by the -do period structural formula) was used. A magnetic tape was prepared using the same amount of oil as in Example 1, except that the same amount of oil was used.

Comparative Example 2 In the composition of the magnetic paint in Example 1, actual j11
Example 11 Magnetic fabric was prepared in the same manner as Example 1, except that the modified organic silicone compound having the structural formula shown in Example 1 was replaced with the same amount of a silicone compound represented by the following structural formula. I made a tape.

The magnetic tapes obtained in each Example and each Comparative Example were tested for durability and measured for friction coefficient.

Durability tests were carried out under the conditions of 35°C and 80% RH, with a head load of 10 kg and a running speed of 4.8 cm/sec.
The magnetic tape was run 200 times under the same conditions as the durability test to determine the friction coefficient. The coefficient of friction with the subsequent magnetic head was measured.

The table below shows the results.

As is clear from the table above, the magnetic tapes obtained by the present invention (Examples 1 and 2) are different from the conventional magnetic tapes (Comparative Examples 1 and 2).
and 2), both have a smaller coefficient of friction and better durability, which indicates that the magnetic 7 obtained by this invention
It can be seen that the recording medium has excellent running stability and durability.

Claims (1)

[Claims] 1 General formula (wherein R4 and R2 are -CH, ttake -R3
NO2 and R5 represent hydrocarbons J with carbon taste 1 to 26 1
−snl and n2 keU≦n1<1000゜1≦02≦
500, an integer of n1+02≦1000. ) is a magnetic layer containing an organosilicone compound represented by