KR950012365B1 - Magnetic recording medium with excellent running and durability and manufacturing method thereof - Google Patents

Abstract

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Description

[Name of invention]

Magnetic recording medium with excellent running and durability and manufacturing method thereof

Detailed description of the invention

The present invention relates to a magnetic recording medium having excellent running and durability and a method of manufacturing the same.

In particular, the present invention provides a magnetic recording medium for forming a magnetic layer by applying a magnetic component composed mainly of magnetic powder, a binder and a curing agent on a nonmagnetic support, using a titanium compound represented by the following general formula (I) as a curing aid. A magnetic recording medium manufactured and a method of manufacturing the same.

Wherein n is an integer from 1 to 4, m is an integer from 1 and 2, R is an aromatic or aliphatic chain consisting of carbon, oxygen and hydrogen having 7 or less carbon atoms, and R 'is carbon having 20 or less carbon atoms, Aromatic or aliphatic chains consisting of phosphorus, oxygen and hydrogen.

[Prior Art and Problem]

In the prior art, in USP 3490946, 3492235, 3837912, 3983302, 4431702, fatty acids and fatty acid esters were used alone or in mixture.

However, when fatty acids or fatty acid esters are used alone or in combination, the overall binder structure is plasticized to lower the physical properties of the tape.

Here, a curing catalyst (Ferric acetoacetylate or Dibutyltin Laulaxate) was also used. When such a curing catalyst is used, the pot life of the magnetic paint drops sharply, causing many problems in the manufacturing process and hardening even in the paint state, thereby deteriorating the electronic characteristics.

In addition, USP 4238548 used a polymer having a high rigidity or a high molecular weight as a binder. When a polymer having a high rigidity or a high molecular weight was used, the curing temperature must be increased because of a slow moving speed in the magnetic layer of the polymer. Bad effects such as blooming occur.

In addition, even if the temperature is increased, since the glass transition temperature of the polymer is also high, actual curing does not occur sufficiently.

[Configuration of Invention]

In order to solve the above-mentioned problems, the present invention uses a compound having the following two functional groups with a relatively fast moving speed in a magnetic layer as a curing aid, so that the curing reaction takes place quickly even at a low curing temperature so that sufficient curing is achieved. And it is characterized by providing a magnetic recording medium excellent in running and durability by improving scratch resistance.

Wherein n is an integer of 1-4, m is an integer of 1 and 2, R is an aromatic or aliphatic chain consisting of C, O, H with 7 or less carbon atoms, and R 'is C with 20 or less carbon atoms An aromatic or aliphatic chain consisting of, P, O, H.

[Actions and effects]

As high quality magnetic recording media, high rigidity and high molecular weight polymers are used, which causes the above-mentioned problems.

Therefore, when the magnetic recording medium is prepared using the compound represented by Formula (I) as a curing aid, not only can the curing be sufficiently performed at low curing temperatures, but the compound represented by Formula (I) has a lower molecular weight than the binder. Its relatively fast movement speed makes it easy to participate in the curing reaction. Since the compound of formula (I) has two or more functional groups, that is, a reactor that can participate in the curing reaction, it acts as a bridge between the actual curing agent and the binder to perform the curing. Complete enough.

This role can be easily seen by the following schematic diagram.

That is, since it increases the probability that the binder and the curing agent can react, the curing can be sufficiently made, thereby reducing the friction coefficient and improving the scratch resistance, thereby providing a magnetic recording medium having excellent running and durability.

In the present invention, examples of representative curing aids represented by the general formula (I) are illustrated by chemical names as follows.

Isopropyl tris dioctyl pyrophosphate titanate, tetra isopropyl bis dioctyl phosphate titanate, tetra octyl bistridecylphosphate titanate (tetra octyl bis ditri decyl phosphate titanate, bis dioctyl pyrophosphate oxyacetate titanate, bis dioctyl pyrophosphate ethylene titanate, and isopropyl dioctyl pyrophosphate titanate pyrophosphate titanate).

The amount of the curing aid may include 0.01-10.00 parts by weight based on the magnetic component, but most preferably 0.03-3.00 parts by weight.

If it is 0.01 parts by weight or less, the effect of the present invention does not appear, and if it is 10.00 parts by weight or more, the curing rate of the magnetic material in the magnetic layer is lowered, not only the electron conversion characteristics are lowered, but also may cause head contamination.

In the present invention, as the vinyl chloride-vinyl acetate copolymer used as the binder resin, vinyl chloride-vinyl acetate copolymer, vinyl chloride-vinyl acetate-vinyl alcohol copolymer, vinyl chloride-vinyl acetate, maleic acid copolymer, vinyl chloride propionic acid Vinyl copolymers and the like are suitable.

This kind of vinyl chloride acetate acetate copolymer has good affinity with the magnetic powder, so the dispersibility of the magnetic powder is excellent and the electron conversion characteristics are improved.

As such vinyl chloride vinyl acetate copolymers, U.C.C VYHH, VAGH, VMCH, VYLF, Tenkavinyl, etc., manufactured by Electrochemical Industries, Inc., are commercially available.

Moreover, nitrocellulose etc. are suitable as a cellulose resin used as binder resin.

Like the vinyl chloride vinyl acetate copolymer described above, this kind of fibrous resin also has excellent affinity with the magnetic powder, so the dispersibility of the magnetic powder is excellent, and the hydroxyl group in the molecular chain is enhanced. When used together with a curing agent such as polyurethane resin and colononel, it crosslinks very rapidly under the action of the curing aid of compound (I) to form a three-dimensional network structure, thus forming a strong magnetic layer, and improving the wear resistance and durability of the magnetic layer. .

As the polyurethane resin, urethane elastomers and urethane prepolymers conventionally used in combination are most suitable. Polyurethane-based polyurethane resins may be used.

In particular, the hydroxyl group contained in the sock end or the molecular chain is more suitable because it improves the dispersibility of the magnetic substance. Examples of such a polyurethane-based resin (trade name) Pandex T-5021, Pandex T- 5250, Estane 5703 manufactured by Goodrich Co., Ltd., Estan 5706, N-2301, N-2303 manufactured by Japanese Polyurethane Co., and the like.

This type of polyurethane resin also has good affinity with the magnetic powder, and excellent dispersibility of the magnetic powder.

When such a polyurethane resin is used together, the dispersibility of the magnetic powder is improved, the surface smoothness of the magnetic layer is also improved, and the electron conversion characteristics are further improved.

When forming the magnetic layer containing such a binder resin, the magnetic powder used is, for example, r-Fe ₂ O ₃ powder, Fe ₃ O ₄ powder, Co-containing r-Fe ₂ O ₃ powder, Co-containing Fe ₃ O ₄ powder CrO ₂ powder, Co ferrite powder, Ba ferrite powder, and other conventionally known magnetic powders such as metal powder such as Fe powder and Co powder are included, and as organic solvents, cyclohexanone, methyl ethyl ketone, tetrahydrofuran , Methyl isobutyl ketone, toluene and the like may be used to dissolve the binder resin, any conventionally known organic solvent may be used alone or in combination.

Next, the present invention will be described in more detail as examples and comparative examples.

Evaluation method of the product produced in each embodiment is as follows and is not limited to the embodiment of the present invention.

1. Friction coefficient: It was measured by the method according to ASTM D 1984-73, and it decreased generally with increasing stiffness and elastic modulus at 2% elongation. The smaller this value, the better.

2. Still duration: First, the magnetic recording medium is used as a video tape, and the image is recorded first, and the still image is reproduced.

At this time, the time from the stop time until the image is distorted is measured, and the longer the time, the better the driving performance and excellent durability.

3. Tetri hydrofuran (THF) test: Records the number of times the magnetic layer begins to rub off with a cotton swab moistened with THF. The higher the number, the better the solvent resistance and hardening of the magnetic layer.

Example 1

100 parts by weight of Co-containing r-Fe ₂ O ₃ powder

Vinyl chloride vinyl acetate vinyl alcohol copolymer 10 〃

Polyurethane resin 10 〃

Stearic acid 1 〃

Mystic acid 1 〃

Normal Butyl Stearate 1 〃

Mixed solvent 250 용

(MEK: toluene: cyclohexanone = 1: 1: 1: 1) by weight ratio

Polyisocyanate (colonate L) 3 〃

Isopropyl dioctyl pyrophosphate titanate 0.5 〃

The magnetic coating prepared as described above was coated or dried to a thickness of about 5 µ on a 15 µ polyester film substrate, and then the surface of the magnetic layer was calendered with calendered rolls under pressure and cured at 60 ° C. for 18 hours.

A magnetic recording medium is manufactured by cutting the product thus made in an appropriate direction.

Example 2

Prepared in the same manner as in Example 1, but 0.5 parts by weight of tetra isopropyl bis dioctyl phosphate titanate was added instead of isopropyl dioctyl pyrophosphate titanate.

Example 3

Prepared in the same manner as in Example 1, but 0.5 parts by weight of bis dioctyl pyrophosphate oxiatate titanate was added instead of isopropyl dioctyl pyrophosphate titanate.

Comparative Example 1

Prepared in the same manner as in Example 1, but did not add any curing aid.

Table 1 shows the results of the evaluation test on the samples obtained in the above Examples and Comparative Examples.

TABLE 1

As can be seen from Table 1, the magnetic recording medium produced according to the present invention was found to have a very low coefficient of friction as compared with the conventional one, and extremely excellent in running and durability due to an increase in steel duration and THF test.

Claims (2)

In a magnetic recording medium which forms a magnetic layer by applying a magnetic component composed mainly of magnetic powder, a binder, and a curing agent on a nonmagnetic support, wherein the titanium compound represented by the following general formula (I) is used as a curing aid to the magnetic component. A method for producing a magnetic recording medium by adding 10.00 parts by weight. Wherein m is an integer of 1 and 2, n is an integer of 1 to 4, R is an aromatic or aliphatic chain consisting of carbon, oxygen and hydrogen of 7 or less carbon atoms, and R 'is carbon of 20 or less carbon atoms , An aromatic or aliphatic chain consisting of phosphorus, oxygen and hydrogen. Isopropyl tris dioctyl pyrophosphate titanate, tetra isopropyl bis dioctyl phosphate titanate, tetra octyl bis ditridecyl phosphate titanate, bis dioctyl pyrophosphate oxyacetate A method for producing a magnetic recording medium by adding a compound selected from titanate and isopropyl dioctyl pyrophosphate titanate.