JPS6070524A - Magnetic recording medium - Google Patents

Abstract

PURPOSE:To improve the traveling performance and durability of a magnetic recording medium by using a specified substance as a lubricant. CONSTITUTION:A magnetic layer contg. magnetic powder and a binder as principal components is formed on a nonmagnetic support, and a lubricative layer of sorbitan triester is formed on the magnetic layer. At this time, fatty acid ester is incorporated into the magnetic layer or the lubricative layer to obtain a magnetic recording medium having superior traveling performance and durability. The amount of the lubricants coated to form the lubricative layer is 14- 720mg/m<2>, especially 70-300mg/m<2>, and the weight ratio between the sorbitan triester and the fatty acid ester is 1:3-3:1. When the fatty acid ester is incorporated into the magnetic layer, the amount is 0.15-5.0 parts.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a magnetic recording medium having a magnetic layer on a non-magnetic support, such as a magnetic tape or a magnetic disk.

In particular, magnetic tapes are required to have various characteristics such as a low coefficient of friction, smooth and stable running, a small amount of powder falling off, and good splicability. That is, when a magnetic tape is used in a magnetic recording/reproducing device such as a V'TR, it runs at the same speed while physically contacting tape guides, magnetic heads, etc., so it has excellent wear resistance and can be used for long periods of time. It is important that the shell be able to run stably. For example, if the friction coefficient of the tape surface changes during recording or reproduction, the tape will vibrate at the guide or magnetic head. As a result, the recording/playback signal (for example, an audio signal) on the tape changes in frequency, resulting in a sound different from the original frequency, or the vibration of the tape (
There is a problem that the so-called Q sound) can be directly heard.

To prevent this, magnetic recording media are generally provided with lubricity. For example, a method of forming a magnetic layer by kneading various lubricants with magnetic powder, binder, etc. (internal addition method), or forming a magnetic layer on a non-magnetic support and then forming a slipping layer by surface treatment. method (top coat method). As lubricants, fatty acids and their esters, phosphoric acid esters, silicone oil, etc. are used. However, it is difficult to obtain sufficient running performance, durability, etc. with these lubricants.

In view of the above points, an object of the present invention is to improve the running performance and durability of a magnetic recording medium by using a new lubricant.

In the present invention, a magnetic layer made of magnetic powder and a binder is formed on a non-magnetic support, and a Y11 layer of sorbitan triester is formed on this magnetic layer, so that at least magnetic It is a magnetic recording medium whose sexual characteristic is that a layer or a slippery layer contains a fatty acid ester.

Fatty acid RCOO)I constituting sorbitan triester
is a hydrocarbon; 1.1; 4) in which R has 7 to 21 carbon atoms, is saturated or unsaturated, and is linear or has a side chain can be used. In addition, fatty acid ester R1-COOR2 has R1 and R2 each having 1 carbon number.
~21, a straight-shaped one or one having a side chain can be used.

The amount of lubricant applied (so-called top coat amount) used for the 11-Pi layer is in the range of 14-720/d, especially 70-30
A range of 01111j/rl is desirable. in this case,
The ratio of sorbitan triester to fatty acid ester is 1:3.
-3:1 (weighting) is preferable, and when fatty acid ester is internally added to the magnetic P1 layer, it is 0.15-5. OPHP
(PHP is the ratio of fatty acid ester to 100 parts of magnetic powder) is preferred.

By employing the following configuration, a magnetic recording medium with excellent running properties and durability can be obtained.

The present invention will be explained in detail below.

Example I Co adhesion r Fe20a 100 parts by weight Polyurethane resin 12 parts by weight (N-5033 manufactured by Iyomoto Polyurethane Co., Ltd.) Vinyl chloride
Vinyl acetate copolymer 18 parts by weight (UCC gv/
IGII) Lecithin (dispersant) 1 part by weight Carbon (antistatic agent) 5 parts by weight Methyl ethyl ketone 150 parts by weight Toluene 150 parts by weight After mixing the above composition in a ball mill for 24 hours, hardening agent (Coronate L) 5 parts by weight were added and further mixed for 1 hour. This magnetic paint was applied onto a polyester film having a thickness of 12 μm so that the thickness after drying would be 5 μm, and an orientation treatment was performed to form a dominant layer.

In this magnetic layer, sorbitan trilaurate and isooctyl myristate are dissolved into n-hexane, and people with 1% <
A sample tape was prepared by applying (top coat) a lubricant containing a total of 2% by market weight to form a lubricating layer. The amount of lubricant applied was approximately 1201 lubricants/m.

Example 2 7116 On the magnetic layer obtained in the same manner as in Example 1, 1% by weight each of sorbitan trioleate and isooctyl myristate were dissolved in n-hexane (the total amount of lubricant was 2% by weight). ) and apply the hoof agent to the injury approximately 20 ml! /
Coat to form an outer layer (top coat > sea clr') to create a sample tape.

Example 3 Real Jril! 1.51X parts of isooctyl myristate was added to the composition of the magnetic layer of Example 1, and 1% by weight of n-hexane t of sorbitan trilaurate was added onto the magnetic layer 1.
The amount of sorbitan trilaurate applied is approximately 12
A sample tape was prepared by coating (top coat) to form a slippery layer so as to have a coating density of 0 .mu./d.

Example 4 1.5 parts by weight of isooctyl myristate was internally added to the magnetic layer composition of Example 1, and a 1% by weight n-hexane solution of sorbitan trioleate was applied onto the magnetic layer. 9 was coated (top coated) at a rate of about 120 mm/rrr to form a slippery layer, and a sample tape was prepared.

Comparative Example 1 A sample tape was prepared by adding 1.5 parts by weight of sorbitan trilaurate to the magnetic layer composition of Example 1.

Comparative Example 2 A sample tape was prepared by adding 1.5 parts by weight of sorbitan trioleate to the magnetic composition of Example 1.

Comparative Example 3 The composition of the magnetic layer of Example 1 was added with
A sample tape was prepared by internally adding 1.5 parts of -t.

Comparative Example 4 A sample tape was prepared by adding 1.5 parts by mass of isooctyl myristate and sorbitan trilaurate to the magnetic layer composition of Example 1.

Comparative Example 5 Sorbitan trilaurate was deposited on the magnetic layer of Example 1! Apply 1% n-hexane solution so that the coating amount of sorbitan trilaurate is approximately 120 μ/rrr (1.
A sample tape was prepared by forming a lubricant into a lubricant.

Comparative Example 6 A p% n-hexane solution of sorbitan trioleate was coated on the magnetic layer of Example 1 so that the coating amount of sorbitan trioleate was about 120 μ/l (Tosopco).
1.) A sample tape was prepared by forming a slippery layer.

Comparative Example 7 Example 7i1fi A 1ili% n-hexane solution of isooctyl myristate was applied on the magnetic 1i of Example 1 so that the coating amount of isooctylmyristate was about 120 μ/rd (Top:, l-1-) A sample tape was prepared by forming a slippery layer.

The characteristics of the sample tapes prepared in the above Examples and Comparative Examples are shown in the table below.

table Here, ◯ indicates good, △ indicates poor, and × indicates extremely poor.

As is clear from this table, when a lubricating layer containing a sorbitan triester and a fatty acid ester is formed on the magnetic layer (Examples 1 and 2) and when a lubricating layer containing a fatty acid ester is formed on the magnetic layer (e. When a sexual layer is formed (
In Examples 3 and 4), running performance (friction coefficient and stick
It is possible to obtain a magnetic recording medium that is excellent both in terms of durability (resistance to scratches due to slip) and durability (resistance to scratches during still time).

Note that the fatty acid ester can be added internally to the magnetic layer or
Regardless of whether it was included in the first layer, good results were obtained regarding Mi+ durability. Sorbitan triester is a neo-lubricant with excellent running properties, but when added internally to the magnetic layer, it maintains good properties.
When used in a slippery layer, it exhibited good properties. this is,
When added internally, sorbitan triester (a 111
It is thought that this is because it is adsorbed by the magnetic powder in the layer and becomes difficult to seep out onto the surface of the magnetic recording medium.

Claims (1)

[Claims] A magnetic layer mainly composed of magnetic powder and a binder is formed on a non-magnetic support, a slippery layer of sorbitan triester is formed on the magnetic layer, and at least the magnetic layer or the slippery layer contains a fatty acid ester. A magnetic recording medium comprising: