JPS58199436A - Magnetic recording medium - Google Patents

Abstract

PURPOSE:To enhance electrical characteristics, durability, and abrasion resistance, by forming a megnetic layer contg. soft and hard type urethane resins both specified in tensile strength, and an epoxy resin or its deriv. CONSTITUTION:The soft type urethane resin has <=200kg/cm<2> tensile strength and >=900% elongation at rupture, and the hard type urethane resin has >=200kg/cm<2> tensile strength and <=900% elongation at rupture. Both said resins used for the magnetic recording medium are polyester polyurthane resin or polyether polyurethane resin or the like synthesized by reacting diisocyanate with polyol synthesized from an org. dibasic acid, such as phthalic acid, glycol, such as ethylene glycol, polyol, such as trimethylolpropane, or a lactone type polyesterpolyol.

Description

[Detailed description of the invention] This is related to a magnetic recording medium that has a magnetic force.

Magnetic recording media are usually manufactured by applying a magnetic paint containing magnetic powder and a binder component for binding the powder to the substrate onto a non-magnetic substrate made of polyester film, and drying the coating.

This magnetic recording medium is required to have excellent electrical properties as well as durability and wear resistance. The binder component used for this purpose has excellent dispersibility of the magnetic powder, and can impart excellent electrical properties such as high sensitivity and high S/N ratio to the magnetic recording medium, as well as improve the abrasion resistance and heat resistance of the magnetic layer. There is a need for something that can improve the durability of magnetic recording media.

As described above, the binder component plays an extremely important role in terms of the characteristics of the magnetic recording medium.

Many thermosetting resins or thermosetting resins are used as the polymer used as the binder.
Especially vinyl chloride-vinyl acetate resins, cellulose derivatives, epoxy resins, polyamide trees, etc.

However, when using a mixture of the above resins,
- Sufficient performance could not be obtained in terms of compatibility and dispersibility between resins, as well as abrasion resistance, surface quality, etc. of the manufactured magnetic recording medium.

We are in the business of providing magnetic recording media with

The second objective of the present invention is to provide a magnetic recording medium with excellent wear resistance and abrasion resistance. The third object of the present invention is to provide a magnetic recording medium with excellent surface properties.
It is about providing.

A fourth object of the present invention is to provide a magnetic recording medium with excellent video characteristics.

A fifth object of the present invention is to provide a magnetic recording medium with less dust falling off.

The above-mentioned objects of the present invention are to provide a urethane resin of the type S+9'1,
This is achieved by a magnetic recording medium (hereinafter referred to as the magnetic recording medium of the present invention) having a magnetic layer containing a mixed resin of a hard urethane resin and an epoxy resin band or a derivative thereof.

” It has long been known that a combination of urethane resin and epoxy resin can be used in magnetic recording media after removing the binder component. The reality is that mechanical strength, electromagnetic conversion characteristics, etc. are not sufficient, and a satisfactory magnetic recording medium has not yet been achieved.

The rough urethane resin and hard urethane resin used in the present invention are defined as follows. In other words, a soft polyurethane resin is defined as having a tensile strength of less than 200Ky/- and an elongation at break of 900K or more, and a hard polyurethane resin has a tensile strength of 200Kg/-.
It is defined as di or more and elongation at break is less than 9004, but these measurement methods are, for example, y"x s'K
Details are omitted in L-6a'ox.

The rectangular measurement method will be explained below.

A urethane resin film sample with a thickness of 100μ was heated at 80°C.
10 minutes, followed by heat treatment at 120℃ for 10 minutes, then 25 minutes.
p, left in an atmosphere of 55% RH (relative humidity) for 3 days□
Thereafter, measurements were made under the same conditions in accordance with JISK-630.1 using No. 2 dumbbells at a tensile rate of 2oom for 1 minute.
・11. ,.

The soft-type urethane resin and hard-type urethane resin used in the present invention contain organic dibasic acids such as phthalic acid, adipic acid, trimerized lyluic acid, and maleic acid;
Glycols such as , ethylene glycol, /ropylene glycol, butylene glycol, diethylene glycol, trimethylolpropane, hexane triol. -ru, kuri, serine, trimethylolpropane, hexanetriol, glycerin 2, trimethylono V-ethane 1. Polyvalent alkaline compounds such as penta1eris, lido, and ru
Polyols, dels, polyols, etc. are also synthesized by reaction with any two or more polyols found among these glycols and polyhydric alcohols. ;,or,,. ε-caprolactam, α-
Methyl-1-caprola cutam 1. ε1-Me2. Chill
Lactone-based polyester polyols synthesized from humans, such as 6-, caprolactam, r,-bunarolactam, etc.; or polyols such as polyether polyols synthesized from ethylene oxide, propylene oxide, butylene oxide, etc. Polyester polyurethane resins and polyether polyurethane resins urethanized with diisocyanate compounds such as tolylene diisocyanate*-), 4,4'-diphenylmethane diisocyanate, bexamethylene diisocyanate, and metaxylylene diisocyanate are used. . - These urethane resins according to the present invention are usually produced mainly by the reaction of polyisocyanate and polyol, and free isocyanate and (
or) in the form of urethane resins or urethane prepolymers containing bitroxyl groups or without these reactive end groups, for example in the form of urethane elastomers.

Since the methods for producing urethane resins, urethane prepolymers, urethane elastomers, curing and crosslinking methods, etc. are well known in the art, detailed explanations thereof will be omitted.
, , , 46- The epoxy resin according to the present invention has at least two epoxy groups in the molecule, ■ glycidyl ether type, ■ glycidyl ester type, ■ glycidyl amine type,
There are two types: (1) linear aliphatic epoxide type and (2) alicyclic epoxide type. Preferred is Habisphenol A type diglycidyl ether type, such as Ebiko manufactured by Shell Chemical Co., Ltd.
t ÷ 1004, shrimp) + 1007, shrimp: ff −
) $10F0.9 etc. can be used. This P
JS, those having a melting point of 50°C or higher are preferred.

Epoxy resin derivatives according to the present invention include polyhydroxyl ether type polymers, polyhydroxy polyether esters, etc., and include phenoxy resins and modified resins thereof. Specifically, PKHH manufactured by Union Carbide Co., Ltd. (U3O Company), PKHC, PKHA: Ebikuron 1030.4030, H-3 manufactured by Dainippon Ink and Chemicals Co., Ltd.
There are 30, H-340, H-350, and H-343 townships.

':,''・The soft urethane resin and the hard urethane resin according to the present invention can be used by mixing them in any ratio. It is preferable to mix them in a ratio of 80:20 to 20:80.

The urethane resin consisting of the soft urethane resin and the hard urethane resin according to the present invention and the epoxy resin or its derivatives may be mixed in any proportion, but may be mixed in a weight ratio of 99:1 to 40:60. Preferably.

When an epoxy resin and an epoxy resin derivative are used as a mixture, they may be used in any compatible ratio.

Furthermore, in order to improve the durability of the magnetic recording medium of the present invention, the magnetic layer may contain iso-A-) or polyisocyanate as a hardening agent. The isocyanate used is tolylene diisocyanate; 4.
Examples include 4'-diphenylmethane diisocyanate, hexamethylene diisocyanate, isophorone-containing isocyanate, and the like.

'Polyisocyanate is an adduct of diisocyanate and 9-valent polyol, or
.

-8- There is a decarboxylation compound of a pentamer of isocyanate, 3 moles of diisocyanate, and water.

Examples of these include 3 moles of tolylene diisocyanate,! :, an adduct of 1 mol of methylolpropane, an adduct of 3 mol of metaxylylene diisocyanate and 1 mol of trimethylolpropane, a pentamer of tolylene diisocyanate 1. A pentamer consisting of 3 moles of tolylene diisocyanate and 2 moles of hexamethylene diisocyanate, a decarboxylated product obtained by reacting trimomized hexamethylene diisocyanate with 1 mole of water, and the like can be easily obtained industrially.
, as the magnetic powder used in the present invention, for example, 7
Fezes powder, Fe3O4 powder, Co containing rF
A wide variety of magnetic powders are included, including e*Os powder, Co-containing Fe3O4 powder, CrO2 powder, as well as metal powders and metal alloy powders such as Fe powder and CO powder.

In the present invention, a composition comprising the above-mentioned ferromagnetic powder, a soft type urethane resin according to the present invention, a -do type tsuntane resin chibi epoxy, a resin or a tsuboki resin derivative, or further, Incyanate 9- or a composition to which polyisocyanate is added is mixed and dispersed to obtain a magnetic coating material according to the present invention.

The magnetic paint according to the present invention includes ferromagnetic powder, soft urethane resin according to the present invention, hard urethane resin-epoxy resin, < means epoxy resin derivative and coating solution □
The main component is a medium, and if necessary, a dispersant,
Contains additives such as lubricants, abrasives, and antistatic agents. This magnetic paint is made by dissolving the above composition in an organic solvent.
The magnetic recording layer of the present invention is obtained by forming a magnetic recording layer by dispersing it and coating it on a nonmagnetic support.

Regarding the manufacturing method of the magnetic vibration material used in the present invention,
No. 5-15, No. 39-26794, No. 43-186, No. 47-28043, No. 47-28045, No. 47-28046, No. 47-28048, No. 47-
No. 31445, No. 48-1/1162, No. 48-21
It is described in detail in various publications such as No. 331, No. 48-33683, and Soviet Patent Specification No. 3080.33. 5.]・□ Mixed according to the present invention. Urethane resins and epoxy resins are used as binders, but in the present invention, other known binders may be used in combination as long as the purpose of the present invention is achieved. . Other binders used include unsaturated prepolymers such as maleic anhydride type, urethane acrylic type, epoxy acrylic type, polyester acrylic type, polyether acrylic type, polyurethane acrylic type, polyamide as electron beam curable resin. Examples of the acrylic type and the like or polyfunctional monomers include ether acrylic type, urethane acrylic type, epoxy acrylic type, phosphate ester acrylic type, aryl type, and hydrocarbon type.

Additives used in the magnetic layer according to the present invention will be explained.

Dispersants used include caprylic acid, capric acid,
Groups having Q to 18 carbon atoms such as lauric acid, myristic acid, palmitic acid, stearic acid, oleic acid, elaidic acid, linoleic acid, lylunic acid): alkali metals (Li, Na, etc.) of the above fatty acids or Alkaline earth metals (
A metal soap consisting of Mg, Ca, Ba, etc.) such as lecithin is used. In addition to these, higher alcohols having 12 or more carbon atoms and sulfuric esters may also be used. These dispersants are used in an amount of 1 to 100 parts by weight of the binder.
It is added in an amount of 20 parts by weight.

These dispersants are disclosed in Japanese Patent Publication Nos. 39-28369 and 44
-17945, U.S. Pat. No. 48-15001, U.S. Pat. No. 3,587.993, U.S. Pat.
Graphite, carbon black graft polymer, molybdenum disulfide, tungsten disulfide, 12 carbon atoms
Fatty acid esters (so-called waxes) consisting of a monobasic fatty acid of 16 to 16 and a monohydric alcohol having 21 to 23 carbon atoms in total can also be used. These lubricants contain 0,
It is added in an amount of 2 to 20 parts by weight. Regarding these, publications such as Japanese Patent Publication No. 43-12-23889 and Japanese Patent Publication No. 43-81543, U.S. Patent No. 3470921, U.S. Pat. 523,086
No. 3β25,760, No. 3β3re Bul
Letin Vol, 9. Taki 7. Page 779
(December 1966): ELEKTRONIK 1
961, Ha 12, Page 380, etc.

Commonly used abrasive materials include fused alumina, silicon carbide, oxidized PM, corundum, artificial corundum, diamond, artificial diamond, garnet, and emery (main components: corundum and magnetite). be done. These abrasives have an average particle size of 07) 5 to 5μ.
A size of 01 to 2μ is particularly preferred.
It is. These abrasives are added in an amount of 7 to 20 parts by weight based on 100 parts by weight of the binder. These abrasives are disclosed in Japanese Patent Application Laid-open No. 49-115510 and U.S. Patent No. 3.0.
07β07, 3ρ41J96, 3,687
, 725, British Patent No. 1 145 249, and West German Patent (DT-P8) No. 853 211 13-.

The antistatic agents used include conductive powders such as graphite, carbon black, and carbon black graft polymers; natural surfactants such as saponin; nonionic surfactants such as alkylene oxide, glycerin, and glycidol; Cationic surfactants such as higher alkylamines, quaternary ammonium salts, pyridine, other heterocycles, phosphoniums or sulfoniums: carboxylic acid, sulfonic acid, phosphoric acid, sulfuric acid ester groups,
Anionic surfactants containing acidic groups such as phosphate ester groups, diamino acids, aminosulfonic acids, amphoteric surfactants such as sulfuric acid or phosphoric esters of amino alcohols, and the like are used.

These surfactants that can be used as antistatic agents are disclosed in U.S. Patent No. 4271,623, U.S. Pat. No. 2.240472, U.S. Pat. , same number °-: 2,676.975
No. 4691,566, No. 4727,860, No. 2,730,498, No. 2,742,379
No. 39β91, No. 3ρ68,101,
No. 3,158,484! ↓・No. 14-3.201,253, No. 3,210,191, No. 3,294,540, No. 3415.649, No. 3.441413, No. 3,442 , 654, 3475.174, 3,545,974, OLS 1.94 & 665, British Patent No. 1.077317, 1J98,45
Including specifications such as No. 0, "Synthesis of surfactants and their applications" by Ryohei Oda et al. (Maki Shoten 1964 edition): A, W
"Surface Active Agents" by Bayley (Interscience Published Edition 1958 edition) = "Encyclopedia Opsurf Active Agents" by T. P. Sisley
Volume 2” (Chemical Published Company 1964)
2006 edition): It is described in books such as "Surfactant Handbook" 6th edition (Sangyo Tosho Co., Ltd. December 20, 1966).

These surfactants may be added alone or in combination. These are used as antistatic agents, but sometimes 1? It may also be used for other purposes, such as dispersion, improving magnetic properties, improving lubricity, and as a coating aid.

The magnetic recording layer is formed by dissolving the above composition in an organic solvent and coating it on a non-magnetic support as a coating solution. Examples of organic solvents used during coating include acetone, methyl ethyl ketone (MEK), and methyl. Isobutyl ketone (
Ketones such as MIBK), cyclohexanone; Alcohols such as methanol, ethanol, propatool, butanol; esters such as methyl acetate, ethyl acetate, butyl acetate, ethyl lactate, and glycol acetate monoethyl ether; glycol dimethyl ether;
Glycol ethers such as glycol monoethyl ether and dioxane; Tars (aromatic hydrocarbons) such as benzene, toluene, and xylene; methylene chloride, ethylene chloride, carbon tetrachloride, chloroform, ethylene chlorohydrin, dichlorobenzene, etc. Halogenated hydrocarbons and the like can be used.

, 1 In addition, as materials for the non-magnetic support, polyesters such as polyethylene terephthalate and polyethylene-a6-naphthalate, polyolefins such as polypropylene, plastics such as cellulose triacetate, cellulose diacetate, and cellulose-derived polycarbonate, Non-magnetic metals such as Cu and A4Zn, ceramics such as glass, porcelain, and earthenware are used.

The thickness of these non-magnetic supports is approximately 3 to 100 μm in the case of a film or sheet, preferably 5 to 50 μm.
m, and in the case of disks and cards, 0.5 to 10
This is just a proverb, and if it is drum-shaped, it should be cylindrical, and its shape is determined depending on the recorder used.

The non-magnetic support has a surface opposite to the side on which a magnetic layer is provided for the purpose of preventing static electricity, preventing transfer, etc.
Backcoat) may be used.

Regarding back coats, see, for example, US Pat. No. 4,804.
No. 401, No. 3,293ρ66, No. 3,617.
(No. 78, No. 3,064676, No. 3,734,
No. 772, No. 3,476.596, No. λ643,
No. 048, No. a803,556, No. 2,887.
No. 462, No. 2,923,642, No. 2,997
, No. 451, No. 3.007,892, No. 3.04
No. 1,196, No. 3,115,420, No. 3,1
66.688 No. 0 It is described in each specification.

17- The support may be in any form such as a tape, sheet, card, disk, or drum, and various materials may be selected as necessary depending on the form.

Magnetic powder and the above-mentioned binder, dispersant, lubricant 31i11
Abrasives, antistatic agents, solvents, etc. are kneaded to form a magnetic paint.

For mixing, the magnetic powder and the above-mentioned components are all fed into a kneader simultaneously or one after another. For example, there is a method in which magnetic powder is first added to a solution containing a dispersant and kneaded for a predetermined period of time, and then the remaining components are added and mixing is continued to obtain a magnetic paint.

Various types of crosstalk machines are used to disperse crosstalk. For example, two-roll mill, three-roll mill, Bonyl mill, Pebble mill, Nando, G15 t4 l/-, Sze
gvar i attritor, high speed impeller dispersion machine, high speed stone mill, high speed impact mill, deep kneader
1 High-speed mixer, homogenizer, ultrasonic disperser, etc.

The technology related to crosstalk distribution is 1. Written by T, C, PATTON
ai18-nt Flow and Pigment Dispe
rsion (1964 John = Willey &
(published by 5ons).

Also, U.S. Patent No. 2,581,414, U.S. Patent No. a855,
It is also mentioned in each specification of No. 1.56.

As a coating method for coating the magnetic coating material onto the support to form a magnetic recording layer, air doctor coat), 7-
red coat, air knife coat, squeeze coat,
Impregnated sheets, reverse roll coating, transfer roll coating, gravure coating), kiss coating, cast coating, spray coating, etc. can be used, and other methods are also possible.Specific explanations of these methods can be found in ``Coating Engineering ” pp. 253-277 (March 2, 1972)
(issued on the 0th).

The magnetic recording layer coated on the support by such a method is optionally subjected to a treatment for orienting the magnetic powder in the layer, and then the formed magnetic recording layer is dried (11). Further, the magnetic recording medium of the present invention is manufactured by subjecting it to surface smoothing processing, if necessary, and cutting it into a desired shape. .

In this case, the orienting magnetic field is approximately 500-=
It is about 2000 Gauss υ, and the drying temperature is about 50~1O
The drying time is approximately 3 to 10 minutes.

In-house methods of magnetic powders are also described in the patents listed below. For example, U.S. Patent No. 1ρ49β40
No. 6,359, No. 3,001β91, No. 3,17
No. 2,776, No. 37116.949, No. 3,
Specifications of No. 473,960 and No. 3,681,138, Japanese Patent Publication No. 32-3427, No. 39-28368,
, No. 40-23624, No. 40-23625, No. 4
No. 1-13181, No. 48-13043, No. 48-3
These include various publications such as No. 9722.

The orientation direction of the magnetic material is determined by its use. That is, in the case of sound tapes, small video tapes, and memory tapes, the angle is parallel to the length of the tape, and in the case of broadcast video tapes, the angle is between 30° and 90° to the length.
It is oriented with a tilt of °.

- The present invention will be explained in more detail below with reference to Examples. It will be readily understood by those skilled in the art that the components, proportions, order of operations, etc. shown herein may be modified without departing from the spirit of the invention.

The magnetic recording medium of the present invention can be used not only for audio, video, and computers, but also for magnetic cards, magnetic sheets, magnetic disks, magnetic drums, and the like.

Therefore, the invention should not be limited to the examples below. , .

Example-1 Vandex T-561 as soft urethane resin
0 (manufactured by Dainippon Ink &Chemicals; tensile strength 155K)
f/- breaking elongation 1000 inches), as a hard urethane resin, Suboshi 4216 (manufactured by Dainippon Ink Chemical ■;
Tensile strength 680Kt/-Elongation at break 530tIb),
As an epoxy resin Epicor) 1004 (Shell Chemical ■
The compositions shown in Table 1 below were prepared using the following method. .

21-Table 1 After thoroughly mixing and dispersing the above composition in a ball mill, iso*
o y diisosyphne) (VE'BA-CHEM
(manufactured by IEAG, purity 99%) was further uniformly mixed with 1.05 g of the above composition per 100 g to prepare a magnetic paint. ``This magnetic paint was applied to one side of a polyethylene terephthalate film with a thickness of 15 microns to a dry film thickness of 5 μ'' while applying a magnetic field of 2000 Gauss.The wide sample thus obtained was After calendering, it was slit to a width of 3.81 wm to obtain a sample (A-1) of O22-deotabe of the present invention.

Furthermore, as shown in Table 1, a videotape made using Epicote 10o4 and Crispon 4216 was used as a comparison sample (S-1).

Example-2 MAU-201 was used instead of Bandex T-5610.
0 (manufactured by Dainichiseika Chemical Co., Ltd., tensile strength 3o'7-1, elongation at break 1175%), and Nilaporan N-3022 (manufactured by Nippon Polyurethane Co., Ltd., solid content of ethyl acetate 35%, Tension strength 258Kf/
A sample of the present invention (A-2) of a videotape was prepared in the same manner as in Example-1 using cfIt1 fracture extension goon).
I got it.

The properties of the samples (A-1) and (A-2) of the present invention and the comparative sample (S-1) were measured as shown in Table 2, and the results were obtained.

23- Embroidery Table 2 *1) Optical selectivity ζ standard at 60° reflection: Relative value when the board is 100 degrees.

From the results in Table 2, it can be seen that the samples of the present invention are superior to the comparative samples.゛Example-3□ Co-containing -F instead of 20g of γ-Fe as magnetic powder
A composition as shown in Table 4 consisting of the binder described in Table 5 was prepared using ezes, and the compositions as shown in Table 4 were prepared in the same manner as in Example 1 to prepare samples of the present invention (A=a), (A-4) and comparative samples. Sample (S
22), (S-3), and 5-4) were obtained. However, it is slow.
Table 25 - Table 4 Characteristics of the above inventive samples (A-3), (A-4) and comparative samples (S-2), (S3), (S4) The fifth
The measurement results were obtained as shown in the table.

Table 26-5 From the results shown in Table 5, the samples of the present invention had good tape surface properties, electric particle properties, dust removal, and abrasion resistance (still properties).

*1) Chroma S/N ratio (AM) and Qma signal (358
MHz) was set to 0.714 vp-p, recorded on the luminance signal, played it back, extracted only the chroma signal, and calculated the ratio of its effective value (S) to the noise level when the chroma signal was removed. However, the S-2 sample was OdB.

*2) Methyl characteristic: The time it takes for a still image to disappear; the larger this value is, the higher the durability and abrasion resistance of the magnetic recording medium.

Agent Yoshimi Kuwahara

Claims (1)

[Claims] 1. A soft urethane resin with a tensile strength of less than 200 Kt/a1 and an elongation at break of 900 or more, and a hard type having a tensile strength of 20,047 or more and an elongation at break of less than 900. A magnetic recording medium characterized by having a magnetic layer containing a urethane resin and an epoxy resin or a derivative thereof. 2. The magnetic recording medium according to claim 1, wherein the epoxy resin is a bisphenol AM diglycidyl ether type. 3. The magnetic recording medium according to claim 1, wherein the epoxy resin derivative is a polyhydroxyether type. 4. The magnetic recording medium according to claim 3, wherein the polyhydroxyether polymer is phenoxy resin.