JPS58215475A - Magnetic recording medium - Google Patents

Abstract

PURPOSE:To provide a magnetic recording medium excellent in travelling and adhesion to magnetic layers, and well suited to magnetic tapes for recording, electronic computers, etc., by using a particular polyester as a binder of magnetic layers. CONSTITUTION:An acid component comprising terephthalic acid and/or isophthalic acid and a glycol component consisting mainly of 2-methyl-1,3-propanediol are subjected to esterification followed by polycondensation to yield a polyester, which is used as a binder. Magnetic powder (e.g., gamma-Fe2O3), said polyester, and other additives (pigments, wetting agents, antistatic agents, lubricants, etc.) are dispersed in org. solvents to form a magnetic coating. Said magnetic coating is applied onto a base (e.g., polyester films) and subjected to magnetic orientation. The coated base is then dried to yield a magnetic recording medium of high performance.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a magnetic recording medium, and particularly to a magnetic recording medium with excellent adhesive properties suitable for use in recording tapes and magnetic tapes for electronic payment machines.

Magnetic recording tapes must have magnetic properties suitable for their respective uses. l'l's 51, Iko, 1'', 1.!11
Chicho 11, 1. It is required that the magnetic layer does not move even when running at high speeds or at high speeds.

Generally a) Wandering recording tape (1γ-1zee20a +
The current magnetic powder is applied to Co-containing Fe203 or Crt')2' by vinyl resin, polyamide resin, A I
33 resin (acrylonitrile-butadiene-styrene copolymer) and other binders, and then add additives such as lubricants, antistatic agents, dispersants, and solvents to make magnetic paints, which are then made into acetate. It is obtained by coating 11 on a non-magnetic base 1- such as a polyester base.

For example, it is known that epoxy resin or polyurethane 4111 fat is conveniently used as a binder in order to improve the surface abrasion resistance (σ) and extend the life of the tape. A magnetic layer with improved wear resistance has been obtained by using vinyl-vinyl acetate copolymer resin 4 resin and polyurethane resin as the main components of the binder1. However, depending on the binder composition, Although the above-mentioned abrasion resistance properties can be obtained, the requirements for adhesion are not met.

The present invention aims to eliminate the above-mentioned drawbacks and provide a magnetic recording medium with excellent running properties and adhesive properties.

That is, the present invention provides a magnetic recording medium obtained by coating a magnetic paint made of magnetic powder, a binder, etc. on a non-magnetic base, in which a linear saturated thermoplastic polyester resin is contained in the binder, and the glycol component is mainly 2- Methyl-13
- A magnetic recording medium characterized in that it is made of propanediol and contains as an acid component a polyester consisting of terephthalic acid θ~100 mols and isophthalic acid 100-0 mols.

2-Methyl 1,3-propanediol, which substantially constitutes the glycol component of the linear saturated thermoplastic polyester resin of the present invention, is a diol having one methyl group in the side chain and having an asymmetric chemical structure. It is an extremely effective compound for making the structure of the polyester polymer containing it irregular and thus amorphizing it.Moreover, since both of the two hydroxyl groups are primary, the reaction f1 It easily reacts with compounds containing carboxyl groups such as terephthalic acid and isophthalic acid to form Nisder bonds.

It is clear whether superior adhesive strength can be obtained by using the linear saturated heat 1-plastic polyester resin of the present invention (2-methyl-13-magnetic material and Since it is easy to form coordinate intermolecular bonds and hydrogen bonds with atoms on the surface of the base of the non-magnetic material, adhesion is improved.

The linear saturated thermoplastic polyester resin of the present invention is produced using a mixture of 2-methyl-1;3-propanediol and terephthalic acid or isophthalic acid or terephthalic acid and inphthalic acid as starting materials, but other materials are also used. 'i' combined component 11 - adipic acid, azelaic acid, -L patic acid? C) polyhydric aliphatic carboxylic acid, trimeric 1-acid, 1-bi-11 meridian
1. Acids, 2.6-S Polyaromatic carboxylic acids such as phthalene dicarboxylic acid, ethylene glycol, propylene glycol, neopentyl glycol, 1,4-phthanediol, 16-hexanediol, 14-cyclohexanediol, cyclohexanediol Metatool, trimethylolpropane, and bentaerythritol natonopolyhydric alcohol can be used in appropriate amounts depending on the purpose.

There are four methods for synthesizing the linear saturated thermoplastic polyester resin of the present invention, to which conventionally known polyester manufacturing methods can be directly applied: a method of directly polycondensing a dicarboxylic acid compound and a diol compound; It can be produced by any method of reacting an ester-forming derivative such as a lower alkyl ester of dicarboxylic acid or a halogen derivative with a diol compound.

, - As an example, a method for producing a copolymer obtained from terephthalic acid, isophthalic acid, and 2-methyl-13-propanediol is shown. 1 mol of dimethyl terephthalate, 15 - mol of dimethyl isophthalate, and the number of excess moles, - 1.1 per acid component
~20 times the mole of 2-methyl-1,3-furopanediol was reacted with a conventional Nisderization catalyst under a nitrogen stream under normal conditions.
The transesterification reaction is carried out at a temperature of about 15°C to 2.10°C, methanol is leaked out, and a catalyst is added as necessary.
After adding additives such as color inhibitors, 5 mm TI
Reduction of less than g1. Polycondensation is carried out at about 200-280° C. under IE. A wide range of catalysts can be used as the -1h12 catalyst, including titanium compounds such as tetraethoxytitanium, tetraethoxytitanium, tetrapropoxytitanium, tetraisopropoxytitanium, tetrabutoxytitanium, di-π-butyl-tin-dilaure- 1., di-n-butyl-
Examples include tin compounds such as tin-oxide and diptyl-tin-diacetate, combinations of acetates such as magne/rum, tunorum, and zinc with antimony oxide or the titanium compounds mentioned above. These catalysts produce L
All J8 'Hj Combined K s, + L, 0.002 ~
0.8 1 month within the range of i quantity) and h9 completed 1-
stomach. In addition, phosphorus-containing compounds such as (, [phosphorous acid, trimethylphosphinyl-(i--to), lJtenorphosphate, l-liphenylphosphate, etc.] are effective as coloring inhibitors, and the total copolymer produced It is preferable to use it in a range of 0001 to 03% by weight.

When forming and applying the magnetic layer, it is natural to use pigments, wetting agents, antistatic agents, lubricants, etc. in addition to the binder, and when dispersing the magnetic layer, an organic solvent is used for dispersion. This can be done using conventional techniques known in this field.

EXAMPLES Hereinafter, the present invention will be explained in detail with reference to Examples, but the present invention is not limited thereto.

In addition, "1 part" in the examples means parts by weight.

Synthesis Example 14 970 parts of dimethyl terephthalate, 970 parts of dimethyl isophthalate, 126.2 parts of 2-methyl-1,3-propanediol together with 0.20 part of titanium tetrabutokind catalyst in a reaction vessel equipped with a double helical ribbon stirring blade. The mixture was heated at 180°C for 1 hour and then at 230°C for 2.5 hours in a nitrogen stream at normal pressure, and the resulting methanol was poured into a theoretical amount of 90 ills. : l-metered, 250℃
The temperature was raised to 0.2 mmHg over 40 minutes.
The pressure was reduced to , and the reaction was carried out for 11 hours under these conditions.

The intrinsic viscosity of the obtained polyester resin was 051 (phenol (30 parts, 1.1.2.2-tetrachloroethane 7
IO part mixed solvent).

Example 1 and Comparative Example 1 As a comparative example, Toyobo Vylon 2 Fl 0 was prepared using Irr 1' and solid polyester resin in Synthesis Example 1 under the following preparation conditions.

Polyester resin or Toyobo Vylon 200wofJ agent (
) 20% in toluene/methyl ethyl ketone = s/2)
Dissolve IQ at the concentration of! rl-/l:Oh(.

Similarly, vinyl chloride-vinyl m-acid copolymer resin (product name:
VAG made by UCC Tsuki () is also dissolved in a solvent of the same composition (
.

The following composition was placed in a ball mill and mixed and dispersed for 8 hours.

Polyester 4 resin or Toyobo Byron 200 3
0 parts VAGHts parts Coronene L 3 parts (manufactured by Nippon Polyurethane Co., Ltd.) Iron oxide (γ-Fe2O3) 105 parts Toluene/Methyl Ethyl Ketone - 872270 parts After dispersion, 1 coated on a polyester film with a coater and immediately passed through an orientator at 1800 Gauss for 80 It was dried at ℃ for 4 minutes.

Magnetic coating evaluation 1) Magnetic powder dispersion evaluation method The magnetic steresis curve of the magnetic coating coated on a polyester film was measured using a DC magnetization characteristic automatic recording device Type 3257 (manufactured by Yokogawa Electric Corporation), and the squareness ratio was determined. was calculated and used as the evaluation method for dispersibility.

2) Adhesion evaluation method: The surface of the magnetic coating coated on a polyester film is fixed to a metal plate using an epoxy adhesive and tested using a tensile tester.
O°C peel measurement was performed.

−9= Measurement result 'l'J, f'l Applicant Daicel Chemical Industries, Ltd. −，＋　　1’l　−−−

Claims (1)

[Claims] In a magnetic recording medium obtained by applying a magnetic paint made of magnetic powder, a binder, etc. onto a non-magnetic base, the binder contains a glycol component mainly of 2-methyl-13- as a linear saturated thermoplastic polyester resin. Consists of propanediol, with 0 to 100% terephthalic acid as the acid component.
A magnetic recording medium comprising a polyester having a molar ratio of 100 to 0 and a molar ratio of isophthalic acid.