JPH01311419A - Magnetic recording medium - Google Patents

Abstract

PURPOSE:To improve traveling property and durability by holding a specific dimethylalkylamine. CONSTITUTION:When the dimethylamine expressed by formula I is to be maintained and incorporated into the magnetic layer, 0.01-15pts.wt. is preferably used for 100pts.wt. of the magnetic powder, and more preferably, 0.05-10pts.wt. When it is incorporated in a back coating layer of the nonmagnetic supporting body, 0.5-5pts.wt. if it is used for 100pts.wt. of the binder in the back coating layer, and more preferably, 0.05-5pts.wt. When a top coating layer or coating layer consisting of tirtialy amine compound of formula I is to be formed, the applied amount is preferably 5-1,000mg/m<2>. Thereby, traveling property and durability of the medium can be improved. In formula I, R represents saturated or unsaturated hydrocarbon group having 10-22 carbons.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a magnetic recording medium, and more particularly to a magnetic recording medium with significantly improved running properties and durability.

[Summary of the invention]

The magnetic recording medium of the present invention has excellent running properties and durability by containing a specific dimethylalkylamine therein.

[Prior art and problems to be solved by the invention] Magnetic tapes have a particularly small coefficient of friction, smooth and stable running properties, and a small amount of tape drop.
Various properties are required, such as good splicability.

In other words, when magnetic tape is used in magnetic recording and reproducing devices such as VTRs, it runs at high speed while physically contacting tape guides, magnetic heads, etc., so it has excellent wear resistance and remains stable over long periods of time. It is important to be able to drive in

For example, if the friction coefficient of the tape surface changes during recording or playback, the tape will vibrate at the guide or magnetic head, and as a result, the frequency of the recorded/playback signal (for example, an audio signal) on the tape will change. The sound is different from the original frequency, or the vibration sound of the tape (so-called Q sound)
The disadvantage is that you can hear it directly.

In order to prevent this, various attempts have been made to impart lubricity to the tape. For example, a solid lubricant such as molybdenum disulfide, graphite, or wax is added to a magnetic paint containing magnetic powder and a binder. However, this solid lubricant is undesirable because it is not very effective for durability and, if added in large amounts, deteriorates the magnetic properties.

On the other hand, higher fatty acids, higher fatty acid esters, paraffinic hydrocarbons, silicone oils (e.g. dimethyl silicone oil, diphenyl silicone oil), etc. may be used as lubricants, but even these may provide sufficient durability and lubricity. Therefore, it is insufficient especially for the mains of a VTR. Moreover, blooming in which the lubricant oozes onto the surface of the magnetic layer is likely to occur, causing tape sticking phenomena, stain slips, and the like.

By the way, in order to increase the oxidation resistance of the powder described in JP-A-58-155518 and to increase the adhesion between the magnetic layer and the non-(a) support, an amine compound is contained in the magnetic recording layer. However, this amine compound is not limited to primary, secondary, or tertiary, and in order to achieve the goal of the present invention, it is necessary to use isocyanate as a curing agent for primary and secondary amine compounds. I reacted and started running,
Not only is no effect on durability recognized, but durability also deteriorates because crosslinking of the resin is reduced. Moreover, trihexylamine, triheptadecylamine, etc. are described as tertiary amines, but these do not show any effect on running durability due to poor orientation.

An object of the present invention is to eliminate the above-mentioned disadvantages, and to provide a magnetic recording medium that has excellent runnability and durability (n-feelability, and good electromagnetic conversion characteristics).

[Failure to solve the problem]

As a result of extensive research over a long period of time in order to achieve the above-mentioned object, the present invention has found that the inclusion of dimethylalkyl (carbon number 10-22) amine inside the magnetic recording medium provides excellent running performance and durability. The present invention has been completed based on these findings.

That is, the magnetic recorder of the present invention 2. The technical medium is a magnetic recording medium in which a magnetic layer is formed on a non-magnetic support, and the magnetic recording medium has a general formula: RN (CHz)2 (wherein, R is a saturated or unsaturated carbon atom having 10 to 22 carbon atoms). It is characterized by holding a dimethylalkylamine represented by (representing a hydrocarbon group).

The tertiary amine compound used in the present invention is a compound represented by Noshiro above. If the number of carbon atoms in the hydrocarbon group is O; 1, the effect will be ineffective or the durability will be poor. Examples of the tertiary amine compound include dimethyldecylamine, dimethyllaurylamine, dimethylmyristylamine, dimethylalkylamine, dimethylstearinamine, and dimethyloleylamine.

When the tertiary amine compound is included in the magnetic layer, the proportion of the tertiary amine compound is 0.00 parts by weight based on 100 parts by weight of the magnetic powder in the magnetic layer.
01 to 15 parts by weight is preferred. If it is outside this range, it may not be effective or may adversely affect running performance, which is undesirable. Particularly preferably 0.05 to 10 parts by weight.

Further, when it is included in a back coat layer (described later) on the back side of the non-magnetic support, it is preferably 0.01 to 15 parts by weight based on 100 parts by weight of the binder in the back coat layer. Particularly preferably 0.05 to 5 parts by weight. Further, when a top coat layer or a coating layer (both described below) made of the above-mentioned tertiary amine compound is formed by coating, the coating amount is preferably 5 to loooomg/m.

Furthermore, it is also possible to use the tertiary amine compounds according to the invention in combination with the other conventional lubricants mentioned above.

A magnetic recording medium, such as a magnetic tape, according to the present invention is illustrated in FIGS. 1 to 5.

FIG. 1 shows a nonmagnetic support 1 on which a magnetic layer 2 containing the lubricant of the present invention is formed. Similarly, in the following figures, the layer containing the tertiary amine compound according to the invention is shown in interspersed cross-section.

FIG. 2 shows a state in which a top coat layer 3 made of a tertiary amine compound according to the present invention is formed on the surface of the magnetic layer 2. FIG. 3 shows a state in which a coating layer 4 made of a tertiary amine compound according to the present invention is formed on the back surface of the nonmagnetic support 1. FIG. 4 shows a state in which the tertiary amine compound according to the present invention is contained in the back coat layer 5 formed on the back surface of the non-magnetic support 1, and FIG. Figure 3 shows the formation of a coating N6 consisting of a tertiary amine compound according to the invention. The back coat layer 5 is provided for various purposes, including stabilizing runnability by appropriately controlling the surface roughness of the back surface, and preventing static electricity. For this reason, the back coat layer is coated with a binder mixed with carbon black, or is coated with a non-magnetic pigment such as α-
Fe201, alumina, talc, etc. may be mixed. The magnetic recording medium of the present invention can be used not only for such magnetic tapes but also for magnetic disks having magnetic layers on the front or back surfaces. Further, the position where the tertiary amine compound according to the present invention is held is set in the magnetic layer 2 or on the surface of the magnetic layer 2 and/or
Or on the back side.

Here, the material for the non-magnetic support may be any material that is normally used in this type of magnetic recording medium, such as polyesters such as polyethylene terephthalate, polyolefins such as polyethylene, polypropylene, etc. cellulose derivatives such as cellulose triacetate, cellulose diacetate, and cellulose acetate butyrate; vinyl resins such as polyvinyl chloride and polyvinylidene chloride; plastics such as polycarbonate, polyimide, polyamide, and polyamideimide;
Examples include paper, metals such as aluminum and copper, light alloys such as aluminum alloys and titanium alloys, ceramics, and single crystal silicon. The nonmagnetic support may be in any form such as a filter, tape, sheet, disk, card, or drum.

Moreover, any ordinary ferromagnetic powder can be used as the ferromagnetic powder used in the magnetic layer. Therefore, ferromagnetic powders that can be used include ferromagnetic iron oxide particles,
Examples include ferromagnetic chromium dioxide, ferromagnetic alloy powder, hexagonal barium ferrite fine particles, iron nitride, and the like.

The above-mentioned ferromagnetic iron oxide particles are those whose X value is in the range of 1.33≦X≦1.50 when expressed as -Noshiro PeO, that is, magnetite (γ-Fez02, 'X=
1.50), magnetite (Fe*04, X = 1.
33) and their solid solutions (FeOx, 1.33<X<
1.50). Furthermore, these ferromagnetic iron oxides have
Cobalt may be added for the purpose of increasing coercive force.

There are two types of cobalt-containing iron oxides: doped type and deposited type.

The above-mentioned ferromagnetic chromium dioxide includes Crag or RLISSn, TeX for the purpose of improving coercive force.
5bs Fe5Tix Added with at least one of V, Mn, etc. can be used.

Ferromagnetic alloy powders include Pe, Co, Nis Fe
-C0%Fe-Ni5 Fe-Co-Ni, Co-N
i, Pe-Co-B5Fe-Co-Cr-B5
Mn-B1SMn-AJ, Fe-Co-V, etc. can be used, and they can also be used to improve various properties.
A metal component such as 1,5iSTisCrSMn5CusZn may be added.

As the binder, those conventionally used as binders for magnetic recording media can be used, including vinyl chloride.
Vinyl acetate copolymer, vinyl chloride-vinyl acetate-vinyl alcohol copolymer, vinyl chloride-vinyl acetate-maleic acid copolymer, vinyl chloride-vinylidene chloride copolymer,
Vinyl chloride-acrylonitrile copolymer, acrylic ester-acrylonitrile copolymer, acrylic ester-vinylidene chloride copolymer, methacrylic ester-vinylidene chloride copolymer, methacrylic ester-styrene copolymer, thermoplastic Polyurethane, polyvinyl fluoride, vinylidene chloride-acrylonitrile copolymer, butadiene-acrylonitrile copolymer, acribinitrile-butadiene-methacrylic acid copolymer, polyvinyl butyral, cellulose derivative, styrene-butadiene copolymer, polyester, phenol resin, epoxy resin,
Examples include thermosetting polyurethane, urea resin, melamine resin, alkyd resin, urea-formaldehyde resin, and mixtures thereof. Among these, polyurethane, polyester, acrylonitrile butadiene copolymer, etc., which are said to impart flexibility, are preferred.

A wood-philic polar group may be introduced into these binders for the purpose of further improving dispersibility. The above-mentioned hydrophilic polar groups include -So, 41 group, -O5ChM group, -PO(
OM') 2 groups, -C00M group, -NG, J group (however,
M represents a hydrogen atom or an alkali metal atom, M' represents a hydrogen atom, an alkali metal atom or a hydrocarbon atom, G represents an alkyl group, and J represents a halogen.

) etc.

The polyurethane used as a binder may also be a mixture of polyurethane having epoxy groups and polyurethane having amino groups.

The above-mentioned polyurethane is obtained by the reaction of a polyhydroxy compound and a polyisocyanate, and the polyhydroxy compound and polyisocyanate, which are the main components of the polymer, are long-chain diols with a molecular weight of about 500 to 5,000.
It is preferable to use a short chain diol having a molecular weight of 750 to 500 and an organic diisocyanate.

The long-chain diols are broadly classified into, for example, polyester diols, polyether diols, polyether ester glycols, and the like. Specific examples of polyester diols include aliphatic dicarboxylic acids such as succinic acid, adipic acid, sebacic acid, and azelaic acid, aromatic dicarboxylic acids such as terephthalic acid and isophthalic acid, or lower alcohol esters thereof, and ethylene glycol. , 1.3
-Propylene glycol, 4-butylene glycol, 1,6-hexane glycol, diethylene glycol, neopentyl glycol, or bisphenol A
and lactone-based polyester diols obtained by ring-opening polymerization of lactones such as ε-caprolactone. Examples of polyether diols include polyethylene glycol, polypropylene ether glycol, polytetramethylene ether glycols, or copolymerized polyether ester glycols thereof, which are prepared by reacting the polyalkylene ether glycol with an aliphatic or aromatic dicarboxylic acid as a polyol component. Examples include polyester glycols obtained by If the molecular weight of this long-chain diol is too small, the urethane group concentration of the resulting polyurethane will be too high, resulting in poor polymer flexibility and poor solubility in solvents. It is not very suitable for use as In addition, if the molecular weight of the long chain diol is too large, the long chain diol content in the polymer will be too large (too much), and the urethane group concentration will be relatively very small, resulting in poor wear resistance and heat resistance of the polymer. Sexuality decreases.

The above-mentioned short chain diols include, for example, ethylene glycol, propylene glycol, 1,4-butylene glycol, l,
6-hexane glycol, aliphatic glycol such as neopentyl glycol, or ethylene oxide adduct or propylene oxide adduct of bisphenol A;
There are aromatic diols such as ethylene oxide adducts of hydroquinone, and depending on the properties of the polyurethane, these can be used individually or mixed in various ratios.

Furthermore, glycerin, ethylene oxide adduct of glycerin, 2-methylpropane-1,2゜3-triol, 4-[bis(2-hydroxyethyl)]-]2-hydroxypenkune 3-methylpentane-1,3 ,5-1-
Diol, 1,2.6-hexane glycol, ■-bis(2-hydroxyethyl)amino-2-propatol,
It is also possible to use a triol such as a propion oxide adduct of jetanolamine.

Examples of the organic diisocyanate include aliphatic diisocyanates such as tetramethylene diisocyanate and hexamethylene diisocyanate, m-phenylene diisocyanate, p-phenylene diisocyanate, f-socyanate, and 2,4-tolylene diisocyanate. Isocyanate, 2.6-tolylene diisocyanate, diphenylmethane diisocyanate, 3.3'
-dimethoxy-4,4'-biphenylene diisocyanate, 3,3'-dimethyl-4,4'-biphenylene diisocyanate, 4,4'-diisocyanate diphenyl ether, 1,5-naphthalene diisocyanate, 2 ．．
Aromatic diisocyanates such as 4-naphthalene diisocyanate, 1,3-diisocyanatomethylcyclohexane, 1,4-diisocyanatomethylcyclohexane,
4.4'-diisocyanate dicyclohexylmethane,
Examples include alicyclic diisocyanates such as isophorone diisocyanate.

In addition to the binder and ferromagnetic powder, the magnetic layer also contains additives such as a dispersant, a lubricant, an abrasive, an antistatic agent,
A rust preventive agent or the like may be added. These dispersants, lubricants,
Any conventionally known abrasives, antistatic agents, and rust preventives can be used.

The constituent materials of the magnetic layer described above are prepared as a magnetic paint by dissolving it in an organic solvent and coated on a non-magnetic support.The solvent for the magnetic paint may be acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, etc. Ketone solvents, methyl acetate, ethyl acetate, butyl acetate,
Ester solvents such as ethyl lactate and glycol monoethyl acetate, glycol ether solvents such as glycol dimethyl ether, glycol monoethyl ether, and dioxane, aromatic hydrocarbon solvents such as benzene, toluene, and xylene, and fats such as hexane and heptane. Group hydrocarbon solvents, methylene chloride, ethylene chloride,
Carbon tetrachloride, chloroform, ethylene chlorohydrin,
Examples include organic chlorine compound solvents such as dichlorobenzene.

Further, magnetic recording media to which the tertiary amine compound of the present invention is applied are not limited to so-called coated magnetic recording media in which a magnetic layer is formed by coating together with magnetic powder and a binder as described above, but also metal ferromagnetic thin films. This also applies to type magnetic recording media. This metal ferromagnetic thin film magnetic recording medium is formed by plating, vapor deposition, ion blasting, sputtering, or the like with a magnetic metal, such as C0% Fe, Ni, or an alloy thereof, on a nonmagnetic support. This metal ferromagnetic thin film magnetic recording medium has a high magnetic flux density because it does not require the use of a binder, and is useful for short wavelength, high density recording because it is formed into a very thin layer.

〔Example〕

Hereinafter, specific examples of the present invention will be described, but the present invention is not limited to these examples.

1] [L Ni Co adhesion r Fetus too parts by weight Vinyl chloride copolymer 16 parts by weight (8
7% by weight vinyl chloride, 12% by weight 2-hydroxyethyl methacrylate and 1% by weight 2-acrylamide.
copolymer of sodium 2-methylpropanesulfonate,
Degree of polymerization: Coronated 3.6 parts by weight (polyisocyanate manufactured by Nippon Polyurethane Co., Ltd.) Carbon blank (antistatic agent) 2 parts by weight Alumina (abrasive) 2 parts by weight Stearic acid (lubricant) 0.5 parts by weight Isooctyl myristate (lubricant) 1 part by weight methyl ethyl ketone
100 parts by weight Toluene 60 parts by weight Cyclohexanone 60 parts by weight The above composition was mixed in a ball mill for 24 hours, filtered through a 3 μm filter, and then placed on a 14 μm thick polyethylene terephthalate film with a dry film thickness. It was coated to a thickness of 6 μm. Next, after performing magnetic field orientation treatment,
It was dried and rolled up. After further supercalendering, heat treatment was performed at 75°C for 24 hours.
A sample tape was prepared by cutting to a width of 1/2 inch.

When producing the sample tape, the type, amount, and portion of the tertiary amine compound were determined as shown in the table.

For each sample tape obtained, the coefficient of friction (μ),
Frictional fluctuation force and S/N deterioration after 50 passes were measured.

The results are also shown in the table.

Comparison Example 2 The sample tapes of Examples 1 to 7 were carried out as shown in the table in place of the tertiary amine compound.

Similar measurements were made for each sample tape obtained. The results are also shown in the table.

(Left below) [Effects of the Invention] As detailed above, the durability and running properties of the magnetic recording medium have been significantly improved by incorporating a specific tertiary amine into the medium. It is useful and has great industrial value.

[Brief explanation of the drawing]

1 to 5 are cross-sectional views showing embodiments of magnetic recording media according to the present invention. In addition, in the symbols used in the drawings, 1-----1-Nonmagnetic support 2--11--Magnetic layer 3- ・-・-m=・-Top coat polishing 4.6・-・−
1--Coating layer 5-- Back coat layer.

Claims (1)

[Claims] A magnetic recording medium having a magnetic layer formed on a non-magnetic support, wherein the magnetic recording medium has a general formula: RN(CH_3
)_2 (wherein R represents a saturated or unsaturated hydrocarbon group having 10 to 22 carbon atoms).