KR910002984B1 - Magnetic recording media - Google Patents

Abstract

The magnetic recording medium having a magnetic layer on the non- magnetic substrate contaihs an ester compound prepared from trimethylol melamine (or hexamethylol melamine) and fatty acid in the ratio of 30:70-70:30 by weight. The addition amount of the ester compound is 0.1-5.0 parts wrt 100 parts magnetic powder of the magnetic layer. The doping amount of ester compound is 0.1-100 mg/m2 for the top-conted layer of base film. The medium has a good abrasion resistance and running stability.

Description

Magnetic recording media

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic recording medium, and more particularly, to a magnetic recording medium having excellent magnetic recording characteristics and improved running property due to a decrease in the friction coefficient of the magnetic layer. The magnetic recording tape is made by dispersing a magnetic component having a needle shape of 0.5 μm or less in a binder solution together with additives such as lubricant, dispersant, abrasive, and antistatic agent to make a magnetic paint and apply it onto a polyester base film.

After applying the magnetic paint, the tape is passed between magnetic fields made of opposing magnets. The magnetic components are arranged so that the longitudinal direction of the magnetic component having needle shape becomes the running direction of the tape, and then dried and calendered. Then cut to 1/2 inch wide.

The magnetic recording tape manufactured in this way is used by a magnetic recording / reproducing apparatus including a VTR. In use, the tape is physically connected to parts such as tape guides and magnetic heads, and has a relative speed of 4 to 6 m / sec. It is required to have excellent wear resistance, a low coefficient of friction, and good running performance in relation to running under high speed conditions.

In order to impart this property, conventionally, myristyl alcohol (C ₁₄ H ₂₉ OH) and stearyl alcohol (from 14 to 18 hydrocarbons in monovalent saturated aliphatic higher alcohols as a tape imparting agent) C ₁₃ H ₂₇ OH), Cetyl alcohol (C ₁₃ H ₃₃ OH) and the like or a method using two or more (Sung 44-17945), the general formula R ((CH ₂ ) having a -CF ₃ group at the terminal nO} mH (wherein R is a fluoroalkyl group having 2 to 12 carbon atoms, m and n are integers of 1 to 3) and the ratio of the lipophilic portion length to the hydrophilic portion length is greater than 1 (Japanese special application 60-48047), method of using ester of tris- (2-hydroxyethyl) isocyanate and fatty acid (Japanese special application 60-136033), R ₁ COO (C ₂ H ₄ O) m1 (CH ₂ ) nO (C ₂ H ₄ O) m ₂ COR ₂ ... (1) wherein R ₁ and R ₂ are saturated or unsaturated hydrocarbons having 5 to 17 carbon atoms; m ₁ and m ₂ are integers of 1 to 5; n is an integer of 2 to 10; Method using a compound and a higher fatty acid ester (one place 60-193133), method using an ester of pentaerythritol and a fatty acid (one place 60-195735), method using melamine cyanuric acid (one place 60- 234223), a method of using an organosilicon compound (Korean Patent Publication 79-682), and the like have been proposed.

However, when the above compounds are used, it is difficult to maintain sufficient durability and lubricity over a long period of time, and sufficient lubricity cannot be maintained at high temperature, high humidity, or low temperature, and the lubricant on the running of the tape is reduced due to a decrease in affinity and dispersibility for the binder. Dropping or disappearing makes it difficult to stably run and also adversely affects the playback device. In addition, unevenness is caused on the magnetic recording surface, and thus it is impossible to exert sufficient functions as a magnetic recording medium.

Therefore, the present invention is devised to solve the above-mentioned problems and to improve the driving performance of the magnetic recording medium.

That is, the present invention relates to a magnetic recording medium in which a magnetic recording medium having a magnetic layer on a nonmagnetic support contains an ester compound composed of trimethylol melamine or hexamethylol melamine and a fatty acid. .

The ester compound used for this invention may use any of a monoester, diester, triester, tetraester, pentaester, and hexaester. On the other hand, when the fatty acid is represented by RCOOH, the carbon number of R is preferably in the range of 7 to 22.

In the present invention, the addition amount of the ester compound consisting of trimethylol melamine or hexamethylene melamine and fatty acid is preferably 0.5 to 5.0 parts by weight based on 100 parts by weight of the magnetic powder in the magnetic layer, and when it is 0.1 parts by weight or less, the activity cannot be imparted. In the case of more than a weight part, a lubricant is attached to the back surface of the wound tape, which contaminates the traveling system of the magnetic recording and reproducing apparatus while running the tape, and also makes it difficult to run uniformly.

In addition, when used for the self-coated back surface of the base film, it is preferable to add 0.1 to 20.0 parts by weight based on 100 parts by weight of the binder. On the other hand, when the top coating layer is applied, the coating amount of the ester compound of the present invention is preferably 0.1 to 100 mg / m 2.

As the form which apply | coats the ester compound of this invention to a magnetic recording medium,

(1) A method of forming a magnetic layer containing an ester compound of the present invention on the surface of a nonmagnetic polyester base film.

(2) A method of forming a top coating layer of the ester compound of the present invention on the surface of a magnetic layer.

(3) A method of forming a coating layer on the back of a polyester base film using the ester compound of the present invention.

(4) A method of forming a magnetic layer using the ester compound of the present invention on the front and back of a polyester base film.

(5) A method of forming a top coating layer of the ester compound of the present invention on the front and back surfaces of a polyester base film.

Etc. can be mentioned.

The main purpose of forming a coating layer on the back surface of the polyester base film of (3) is to appropriately adjust the surface roughness of the back surface of the base film to stabilize the running performance of the tape and to obtain an antistatic effect. It is also possible to mix and apply a soluble inorganic substance (α-Fe ₂ O ₃ , alumina, etc.).

The magnetic recording medium produced by the present invention has excellent magnetic recording characteristics compared to the conventional ones, and it has been found that the driving performance is extremely excellent due to the reduction of the friction coefficient of the magnetic layer. It can also be applied to magnetic disks and the like.

Example 1

Co-γ-Fe ₂ O ₃ 100 parts by weight

9.0 parts by weight of polyurethane resin

12.5 parts by weight of nitro cellulose resin

Carbon black 4.5 parts by weight

Alumina 3.0 parts by weight

0.5 parts by weight of myristic acid

Cyclohexanone 35.0 parts by weight

Methyl ethyl ketone 120.0 parts by weight

Toluene 64.5 parts by weight

The composition was used as the base composition, and 1.5 parts by weight of triester, which is a compound of trimethylol melamine and stearic acid, was added to the magnetic powder of the base composition, followed by mixing for 4 hours using DYNO-MILL (manufactured sand mill (model KDL)). After passing through the mixture, 4.0 parts by weight of a curing agent was added immediately before application, followed by stirring for 30 minutes.

The magnetic coating thus prepared is coated on a polyester base film having a thickness of 10 μm so that the thickness after drying is 4.5 μm, the magnetic field is oriented, and then dried and wound up. This was calendered and cut to 1/2 inch wide to make a sample tape.

Example 2

It carried out similarly to (Example 1) except having added 1.5 weight part of hexaester which is a compound of hexamethylol melamine and oleic acid with respect to the magnetic powder of the basic composition of (Example 1).

Example 3

It carried out similarly to (Example 1) except having added 1.5 weight part of triesters which are a compound of trimethylol melamine and myristic acid with respect to the magnetic powder of the basic composition of (Example 1).

Example 4

A sample tape was prepared in the same manner as in (Example 1) using the basic composition of (Example 1) as a magnetic paint, and 1.0 weight of triester, which is a compound of trimethylol melamine and oleic acid, on the magnetic layer of the sample tape. Top-coated n-hexane solution contained% but the sample tape was made of 85 mg / ㎡ a triester coating amount.

Example 5

Using the basic composition of (Example 1) as a magnetic diagram, a sample tape was made by the same method as in (Example 1), and a hexaester, which is a compound of hexamethylol melamine and oleic acid, was 1.0 on the magnetic layer of the sample tape. Top-coating the n-hexane solution contained by weight, but a sample tape with a hexaester coating amount of 85 mg / ㎡ was made.

Example 6

A sample tape was prepared by the same method as in (Example 1) using the basic composition of Example 1 as a magnetic paint, and the ester of trimethylol melamine and myristic acid was 1.0 on the magnetic layer of the sample tape. Top-coating the n-hexane solution contained by weight, but a sample tape of 85 mg / ㎡ applied amount of the triester was made.

Comparative Example 1

A sample tape was prepared in the same manner as in (Example 1) using the basic composition of (Example 1) as a magnetic paint.

Comparative Example 2

It carried out similarly to (Example 1) except having added 1.5 weight part of triesters which are a compound of trimethylol melamine and capric acid with respect to the magnetic powder of the basic composition of (Example 1).

The characteristics of the sample tapes made as examples and comparative examples are shown in the table below.

* Aging: It was left for 2 days under the conditions of 40 degreeC and 80% RH.

As shown in the above table, it can be seen that the magnetic recording medium using the lubricant according to the present invention can satisfactorily suppress the coefficient of friction to a small value, and hence the running property is also good. On the other hand, as shown in the comparative example, when the aliphatic hydrocarbon carbon number is less than 7 it can be seen that the activation is significantly reduced.

Claims (5)

A magnetic recording medium having a magnetic layer on a nonmagnetic support, wherein the magnetic recording medium contains an ester compound composed of trimethylol melamine or hexamethylol melamine and a fatty acid. The magnetic recording medium according to claim 1, wherein the amount of the ester compound added is 0.1 to 5.0 parts by weight based on 100 parts by weight of the magnetic powder in the magnetic layer. 2. The magnetic recording medium of claim 1, wherein when the ester compound is used on the magnetic coated back side of the base film, 0.1 to 20.0 parts by weight is added to 100 parts by weight of the binder used in the magnetic layer. The magnetic recording medium according to claim 1, wherein the amount of the ester compound applied to the top coating layer of the base film is 0.1 to 100 mg / m 2. The magnetic recording medium according to claim 1, wherein the weight ratio of trimethylol melamine or hexamethylol melamine and fatty acid is 30:70 to 70:30.