JPS62252521A - Magnetic recording medium - Google Patents

Abstract

PURPOSE:To decrease the coefft. of friction of a magnetic layer and to improve the running characteristic thereof by using a modifying agent which is the resulted product of reaction of a fluorine compd. having a reactive org. functional group and org. polyisocyanate and has a free isocyanate group. CONSTITUTION:This recording medium consists of a nonmagnetic base and the magnetic layer provided on one face of the base. The magnetic layer is formed of a dispersion consisting of a binder resin, the modifying agent for the binder resin and medium. The modifying agent is the resulted product of reaction of the fluorine compd. having the reactive org. functional group and the org. polyisocyanate and has at least one free isocyanate group. The binder resin is thereby not limited to a polyurethane resin and various binder resins are easily usable. The magnetic recording medium having the low coefft. of friction is thus obtd.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention relates to a magnetic recording medium, and more specifically, the present invention relates to a magnetic recording medium, and more particularly, the present invention relates to a magnetic recording medium, and more specifically, a high-performance magnetic recording medium whose magnetic layer is formed from a binder resin and magnetic particles modified with a specific modifier. Related to magnetic recording media.

(Prior Art) Conventionally, magnetic recording media used in audio equipment, computers, etc. are obtained by forming a magnetic layer made of magnetic particles and a binder resin on a nonmagnetic support such as a polyester film.

Such a magnetic layer is formed by coating a support with a dispersion in which magnetic particles are dispersed in a medium containing a binder resin.

The magnetic layer is required to have various physical properties, but the particularly important required performance is good running properties of the magnetic recording medium, and for this purpose it is strongly recommended that the coefficient of friction between the recording head and the magnetic recording medium be low. required. The level of such friction coefficient is mainly determined by the binder resin used to form the magnetic layer.

Conventionally, as binder resins, vinyl chloride resins, polyurethane resins, polyester resins, nitrocellulose resins, epoxy resins, etc. are mainly used alone or in combination.

(Problem to be solved by the invention) The coefficient of friction of the binder resins conventionally used as described above is generally 0.
．． 4 or more, and when magnetic recording media formed from these binder resins are used as video tapes, audio tapes, etc., the slipperiness of the tape is insufficient, so high-speed use such as winding and rewinding of the tape is required. In this case, irregular winding occurs, causing deformation and damage to the tape, resulting in dropouts.

As a method to solve these drawbacks and lower the coefficient of friction of magnetic recording media, fatty acids, wax,
A method of adding a lubricant such as silicone oil has been used, but another disadvantage of this method is that the lubricant added to the magnetic layer bleeds out onto the tape surface, causing clogging of the recording head. occurs.

As a method to solve the above-mentioned drawbacks, it has been proposed to use a resin with a low coefficient of friction as the binder resin itself, such as a polyurethane resin having a siloxane bond in one molecule (for example, Japanese Patent Application Laid-Open No. 57-176535
No. 59-94237, No. 59-5421, No. 5
No. 8-218034, No. 58-222436, No. 59
-11535, Publication No. 59-82636, etc.)
.

According to such a method, a magnetic layer with a relatively low coefficient of friction can be formed, but since the polyurethane resin having siloxane bonds contains siloxane bonds in the main chain of the polymer, sufficient reaction cannot be achieved. It is difficult to obtain a binder resin of constant quality, the price is high, and various problems arise due to unreacted silicone compounds.

Furthermore, since the polymer is limited to polyurethane resins, there is a problem in that the range of use thereof is significantly limited.

As a result of intensive research in order to solve the above-mentioned drawbacks of the conventional technology and meet the above-mentioned demands, the present inventor has discovered that when modifying a binder resin using a specific modifier when manufacturing a magnetic recording medium, The present invention was developed based on the discovery that the above-mentioned drawbacks of the prior art are solved, the binder resin is not limited to polyurethane resins, various binder resins can be easily used, and a magnetic recording medium with a low coefficient of friction can be provided. completed.

(Means for Solving the Problems) That is, the present invention comprises a non-magnetic support and a magnetic layer provided on one surface of the support, and the magnetic layer includes magnetic particles, a binder resin, and a binder resin. The modifier is a reaction product of a fluorine compound having one reactive fabric functional group and an organic polyisocyanate,
The present invention is a magnetic recording medium characterized by having a number of free isocyanate groups.

To explain the present invention in more detail, the binder resin modifier used in the present invention and which primarily characterizes the present invention is a reaction product of a fluorine compound having a reactive organic functional group and an organic polyisocyanate. The reaction product has at least one free isocyanate group in one molecule.

The fluorine compound with a reactive organic functional group used to obtain such a modifier is an amino group.

Any compound that can react with an isocyanate group such as a carboxyl group, hydroxyl group, or thioalcohol group may be used, but a particularly preferred example is a fluorine compound represented by the following formula.

(1) 1((CF2CF2)ncH2DH(n=1~
? )(2) CF3(C:F2CF2)ncH2cH2
0H (n=1-10) (3) CF3 (CF2CF2)
ncOOH(n-1~10)(4) CF3(CF2C
F2) ncH2cH2sH (n-1 to 10) The compounds exemplified above are preferred examples of fluorine compounds in the present invention, and the present invention is not limited to these examples, and the compounds exemplified above and others These fluorine compounds are currently commercially available and can be easily obtained from the market, and any of them can be used in the present invention.

The organic polyisocyanate used in the present invention and which is the second characteristic of the present invention is a compound having at least two isocyanate atoms in an aliphatic or aromatic compound, and has traditionally been used as a raw material for the synthesis of polyurethane resins. Widely used.

Any of these known organic polyisocyanates are useful in the present invention. Particularly preferred organic polyisocyanates are as follows.

Toluene-2,4-diisocyanate, 4-methoxy-
1,3-phenylene diisocyanate, 4-isopropyl-1,3-phenylene diisocyanate, 4-chloro-1,3-phenylene diisocyanate, 4-butoxy-1,3-phenylene diisocyanate, 2,4-diisocyanate-diphenyl ether, mesitylene diisocyanate , 4.4-methylenebis(phenylisocyanate), shrylene diisocyanate, 1.5-naphthalene diisocyanate.

Benzidine diisocyanate, 0-nitrobenzidine diisocyanate, 4,4-dibenzyl diisocyanate, 1,4-tetramethylene diisocyanate, 1,6-tetramethylene diisocyanate.

1.10-decamethylene diisocyanate, 1.4-cyclohexylene diisocyanate, xylylene diisocyanate.

4.4-Methylenebis(cyclohexyl isocyanate).

1.5-tetrahydronaphthalene diisocyanate, and adducts of these organic polyisocyanates with other compounds, such as those of the following structural formula,
Not limited to these.

(Left below) CONH(CH2)8NGO 0NC(CI2)8N C0NH(CH2)8NCO OCH3 The modifier used in the present invention is a combination of a fluorine compound having a reactive organic functional group as described above and an organic polyisocyanate as described above. , in the presence or absence of an organic solvent and a catalyst, at a functional group ratio where the reactive organic functional group and the isocyanate group are in excess of one or more isocyanate groups, preferably 1 to 2, in one molecule. It can be easily obtained by reacting at a temperature of about 0 to 150°C, preferably 20 to 80°C, for about 10 minutes to 3 hours.

The organic solvent that may be used in the production of such a modifier may be any organic solvent as long as it is inert to each reaction raw material and product. For example, preferred organic solvents include methyl ethyl ketone, methyl -n-
Propyl ketone, methyl isobutyl ketone, diethyl ketone, methyl formate, methyl formate, propyl formate, methyl acetate, ethyl acetate, butyl acetate, acetone, cyclohexane, tetrahydrofuran, dioxane, methanol,
Ethanol, isopropyl alcohol.

Butanol, methyl cellosolve, butyl cellosolve, cellosolve acetate, dimethyl formamide, dimethyl sulfoxide, pentane, hexane, cyclohexane,
Examples include heptane, octane, mineral spirit, petroleum ether, gasoline, benzene, toluene, xylene, chloroform, carbon tetrachloride, chlorobenzene, perchloroethylene, trichlorethylene, and the like.

When the modifier obtained as described above and used in the present invention is produced using an organic solvent, it may be separated from the organic solvent, or it can be used as a solution of the organic solvent. The modifier used in the present invention separated from the organic solvent is generally in the form of a white to brown liquid or solid, and is easily soluble in organic solvents used to disperse various magnetic particles.

According to various analyzes 1, such as infrared absorption spectrum, elemental analysis, molecular weight measurement, etc., the modifier used in the present invention as described above shows that the isocyanate group of the organic polyisocyanate and the reactive organic functional group of the fluorine compound are added together. For example, when the reactive organic functional group is an amine group, -
It was revealed that both were bonded together through an NHCONH-bond, and the compound had at least one free isocyanate group in one molecule.

According to detailed research by the present inventors, the modifier used in the present invention contains free isocyanate, and therefore has, for example, a hydroxyl group, a primary to secondary amino group, an amide group, a carboxyl group, etc. It is reactive with various binder resins, and because it is bonded to the main chain of the binder resin as a side chain rather than the main chain of these binder resins, it reduces various properties that binder resins originally have. Without,
It has been found that when binder resin forms magnetic layers, the coefficient of friction of those magnetic layers can be significantly reduced.

Furthermore, this unexpected effect is due to the fact that the modifier used in the present invention has free isocyanate groups.
This is thought to be because the isocyanate groups before, during, or after the formation of the coating film also act as a type of modifier that reacts with each other or with the binder resin.

The dispersion liquid used in the present invention contains the above-mentioned modifier, magnetic particles,
Binder resin and medium are essential components.

The magnetic particles used in the present invention include, for example, iron, chromium, nickel, cobalt, alloys or oxides thereof, and modified products thereof, specifically, for example, γ
-Fe203. Examples include ferrite, magnetite, CrO2, and cobalt-doped bertolide compounds of γ-Fe2O3 and Fe3O4.

The above-mentioned magnetic particles are merely examples, and various magnetic particles other than the above-mentioned examples can of course be similarly used in the present invention, and can be used alone or as a mixture.

In the present invention, the binder resin used is a variety of binder resins that have been conventionally used to form magnetic layers, and any of these can be used, such as vinyl chloride resin, Vinylidene chloride resin, vinyl chloride/vinyl acetate/vinyl alcohol copolymer resin, alkyd resin, epoxy resin, acrylonitrile-butadiene resin, polyurethane resin, polyurea resin, nitrocellulose resin, polybutyral resin, Examples include polyester resins, fluorine resins, melamine resins, urea resins, acrylic resins, polyamide resins, etc. Particularly preferable ones include reactive groups such as those described above that can react with isocyanate groups in their structures. These resins can be used alone or as a mixture, and can be used as a solution or dispersion in an organic solvent.

Further, the reaction between the binder resin and the modifier can be carried out in the presence or absence of an organic solvent and a catalyst at a reaction rate of about 0-150%.
This can be easily carried out by reacting at a temperature of 20 to 80°C, preferably 20 to 80°C, for about 10 minutes to 3 hours.

The medium used in the present invention is the organic solvent used in the preparation of the modifier described above or a mixture thereof.

The dispersion used in the present invention has the above-mentioned components as essential components, and the proportions of these components are the same as in conventional dispersions of magnetic particles. i parts, the magnetic particles account for about 10-50% by weight, the modifier accounts for about 1-50% by weight of the binder resin, the medium accounts for about 50-90% by weight, and the binder The resin is about 5
A range of 20% by weight is common.

As long as the dispersion used in the present invention contains these components as essential components, other subcomponents other than those mentioned above, such as pigments, extender pigments, plasticizers, antistatic agents, surfactants, lubricants, crosslinking agents, aging agents, etc. Inhibitor, stabilizer.

Any additives such as foaming agents and antifoaming agents may be included.

The method for producing the dispersion liquid used in the present invention, which consists of the above-mentioned essential components and optional components, may be any conventionally known method, and generally, the necessary components are added simultaneously or sequentially, and the method includes ball milling, mixer treatment, etc. Mixing and dispersing methods such as processing, roll milling, bead milling, gravel milling, sand milling, and high speed impeller processing are suitable.

The conditions for such dispersion methods themselves vary depending on the type and size of the magnetic particles to be dispersed, their purpose, etc.
Generally, the treatment may be carried out at a temperature of room temperature to 100° C. for about 5 minutes to 20 hours.

In the present invention, the binder resin is a group capable of reacting with an isocyanate group, such as a hydroxyl group, an amine 7
When using binder resins having groups, carboxyl groups, etc., the modifier used in the present invention and these binder resins may be reacted before, during, or after the preparation of the dispersion. This is an embodiment in which the modifier and the binder resin are reacted in advance in preparing the dispersion. Such a reaction can be carried out in the presence or absence of an organic solvent and a catalyst at a temperature of 0 to 120°C, preferably 40 to 80°C, for about 0.5 to 10 hours. In addition, in the present invention, a binder resin that does not have a group that reacts with isocyanate groups may be used. In such a case, the modifiers themselves may be combined with each other, or with a di- or polyfunctional compound, e.g. , water or polyamine increases the molecular weight of the modifier, producing similar effects.

In addition, any conventionally known supports can be used; for example, polyester films, polypropylene films, cellulose triacetate films, cellulose diacetate films, polycarbonate films, etc. with a thickness of 5 to 50 #Lm can be used as desired. can do.

The magnetic layer is formed by applying the dispersion as described above to at least one surface of the support as described above by any method so that the thickness when dried is preferably about 5 to 20 ILm, and then drying. It can be formed by The coating method and drying method may be any conventionally known method.

(Functions/Effects) The magnetic recording medium of the present invention obtained as described above has various properties originally possessed by the binder resin, such as strength, electrical, Because it has a low friction coefficient that cannot be achieved with conventional technology while retaining its chemical and physical properties, it is used in various magnetic tapes, etc., and can be used at high speeds such as winding and unwinding. Also, the tape will not be disturbed, and therefore the tape will not be damaged or damaged.

Furthermore, the modifier used in the present invention does not become the main chain of the binder resin, but rather binds to the binder resin and becomes the side chain of the binder resin, so it is different from conventional polyurethane resins containing siloxane bonds. In contrast, the modifier of the present invention is not limited to modifying polyurethane resins, but can be freely used to modify any binder resin. Therefore, there is an advantage that a magnetic recording medium made of various binder resins and having a low coefficient of friction can be provided without increasing the manufacturing cost of the magnetic recording medium.

Furthermore, since the magnetic layer of the magnetic recording medium of the present invention is formed from a dispersion containing the above-mentioned modifier, after the magnetic layer is formed, the modifier contained in the magnetic layer is mixed with the modifier. However, because the modifier reacts with the binder resin, has a high molecular weight, and is integrated with the binder resin, the modification agent bleeds onto the surface of the magnetic layer over time, causing various problems, as in the conventional technology. has been resolved.

Next, the present invention will be explained in more detail by giving reference examples, examples, comparative examples, and usage examples. Note that parts and percentages in the text are based on weight.

Reference Example 1 (Production example of modifier) Adduct of hexamethylene diisocyanate and water (Duranate 24A-100, manufactured by Asahi Kasei, N00% 23.5)
While thoroughly stirring 52 parts at 60° C., 53 parts of a fluorinated alcohol having the structure shown below was gradually added dropwise thereto to cause a reaction, thereby obtaining 103 parts of a colorless and transparent liquid modifier (Ml).

)1(CF20F2)50)1 According to the infrared absorption spectrum of this modifier, 22707
The absorption due to free isocyanate groups in cm remains,
It showed an absorption band due to 10F2 group at 1190/cm. Furthermore, when the amount of free isocyanate groups in this modifier was quantified, the theoretical value was 2.65%, whereas the actual value was 2.51%.

Therefore, the main structure of the above modifier is estimated to be the following formula.

Reference Example 2 (Production Example of Modifier) Adduct of 1 mol of trimethylolpropane and 3 mol of tolylene diisocyanate (TDI) (Coronate L, EI
Made of genuine polyurethane, N00% 12.5. 75% solids)
While thoroughly stirring 120 parts at 50° C., 114 parts of a fluorinated alcohol having the structure shown below is gradually added dropwise to react.

30 parts of CF3 (CF2CF2) After the reaction was completed, 198 parts of a transparent liquid modifier (M2) was obtained.

According to the infrared absorption spectrum of this modifier, 2270/
The absorption by free isocyanate groups of am remains,
It showed an absorption band due to 10F2 group at 1190/cm. Furthermore, when the amount of free isocyanate groups in this modifier was quantified, the theoretical value was 2.83%, whereas the actual value was 2.68%.

Therefore, the main structure of the above modifier is estimated to be the following formula.

Reference Example 3 (Manufacturing Example of Modifier) 186 parts of an adduct of 1 mol of trimethylolpropane and 3 mol of xylylene diisocyanate (Takenate D11ON, manufactured by Takeda Pharmaceutical, N00% 11.5, solid content 75%) were mixed at room temperature. While stirring, 172 parts of a fluorinated alcohol having the structure shown below was gradually added dropwise to the mixture for reaction.

CF3(CF20F2)3G)12C)1291 (After the reaction was completed, 320 parts of a transparent liquid modifier (M3) was obtained.

According to the infrared absorption spectrum of this modifier, 22707
The absorption by free isocyanate groups of am remains,
An absorption band due to the -CF2- group was shown at 1190/cm. Furthermore, when the amount of free isocyanate groups in this modifier was quantified, the theoretical value was 2.69%, whereas the actual value was 2.51%.

Therefore, the main structure of the above modifier is estimated to be the following formula.

(X=SCH2C)12(CF20F2)30F3)
Reference Example 4 (Preparation of binder resin solution) Polybutylene adipate 15 with a molecular weight of 2,000 having a hydroxyl group at the end
0 parts, 20 parts of 1.3-butylene glycol, and 52 parts of tolylene diisocyanate were subjected to an addition reaction in 412 parts of methyl ethyl ketone to obtain a polyurethane resin solution (solid content 35%) with a viscosity of 200 poise/20°C. Add 5 parts of modifier (Ml) to 100 parts of this polyurethane resin solution,
The reaction was carried out at 0° C. for 3 hours to obtain a modified binder resin solution (UB 1) in which the modifier and the polyurethane resin were combined.

In the binder resin obtained above, no isocyanate group was observed by infrared absorption spectrum. This is presumed to be because the modifier was graft-bonded to the binder resin.

Reference Example 5 (Preparation of binder resin solution) In place of the modifier (Ml) in Reference Example 4, a modifier (M2) was used,
The other conditions were the same as in Reference Example 4, and the modified binder resin solution (U
B2) was obtained.

Reference Example 6 (Preparation of binder resin solution) In place of the modifier (Ml) in Reference Example 4, a modifier (M3) was used,
The other conditions were the same as in Reference Example 4, and the modified binder resin solution (U
B3) was obtained.

Reference Example 7 (Preparation of dispersion) Co-containing Fe2O3 100 parts Polyester type polyurethane resin (35z solution) 54 parts Binder solution (UBI) (35! solution) 20 parts Dispersant (lecithin) 1 part carbon black 5 parts Nitrocellulose
6 parts methyl ethyl ketone
270 parts of the above components were mixed and kneaded in a ball mill for 50 hours, further 8 parts of Coronate L was added, mixed for another 3 hours, and the mixed material was passed through a filter to obtain a dispersion of magnetic particles (UDI).

Reference Example 8 (Preparation of dispersion liquid) A magnetic particle dispersion liquid (UO3) was obtained in the same manner as in Reference Example 7 except that a binder resin solution (UB2) was used instead of the binder resin solution in Reference Example 7. .

Reference Example 9 (Preparation of dispersion liquid) A magnetic particle dispersion liquid (UO3) was obtained in the same manner as in Reference Example 7 except that a binder resin solution (UB3) was used instead of the binder resin solution in Reference Example 7. .

Reference Example 10 (Preparation of binder resin solution) Vinyl chloride/
The modifier (Ml) obtained in Reference Example 1 was added to 100 parts of a methyl ethyl ketone solution (solid content 30%) of vinyl acetate/vinyl alcohol copolymer resin (S-LEC A, manufactured by Mikki Chemical).
Add 3 parts.

The reaction was carried out at 80° C. for 3 hours to obtain a modified binder resin solution (VBI) in which the modifier and the vinyl resin were combined.

In the binder resin obtained above, no isocyanate group was observed by infrared absorption spectrum. This is presumed to be because the modifier was graft-bonded to the binder resin.

Reference Example 11 (Preparation of Binder Resin Solution) A modified binder resin (
VB2) was obtained.

Reference Example 12 (Preparation of Binder Resin Solution) A modified binder resin (
VB3) was obtained.

Reference example! 3 (Preparation of binder resin solution) A modified binder resin (
VB4) was obtained.

Reference Example 14 (Preparation of dispersion liquid) 100 parts of Co-containing Fe2O3 Binder solution (VBI) (30% solution) 20 parts Polyester type polyurethane resin solution (Rezamin ME1
2. (manufactured by Dainichiseika Chemical Industries) 54 parts dispersant (lecithin) 1 part carbon black
5 parts nitrocellulose
6 parts methyl ethyl ketone
270 parts The above components were mixed, kneaded for 50 hours in a ball mill, further added with La part (Coronet), mixed for another 3 hours, and passed through a filter to form a dispersion of magnetic particles (V
DI) I got it.

Reference Example 15 (Preparation of dispersion liquid) A dispersion liquid (VB2) of magnetic particles was obtained in the same manner as in Reference Example 14, using a binder resin solution (VB2) instead of the binder resin solution in Reference Example 14. .

Reference example 18 (preparation of dispersion) Reference example! A magnetic particle dispersion liquid (vn3) was obtained in the same manner as in Reference Example 14 except that a binder resin solution (VB3) was used in place of the binder resin solution in Example 4.

Reference Example 17 (Preparation of binder resin solution) 3 parts of the modifier (Ml) obtained in Reference Example 1 was added to 100 parts of a methyl ethyl ketone solution (solid content 30%) of butyral resin (S-LEC B, @Sui Kagaku), The reaction was carried out at 80° C. for 3 hours to obtain a modified binder resin solution (BBI) in which the modifying agent and butyral resin were combined.

In the binder resin obtained above, no isocyanate group was observed by infrared absorption spectrum. This is presumed to be because the modifier was graft-bonded to the binder resin.

Reference Example 18 (Preparation of Binder Resin Solution) A modified binder resin (
BH3) was obtained.

Reference Example 19 (Preparation of Binder Resin Solution) A modified binder resin (
BH3) was obtained.

Reference Example 20 (Preparation of dispersion liquid) 100 parts of Co-containing Fe2O3 Binder solution (881) (30% solution) 20 parts Polyester type polyurethane resin solution (Rezamin ME1
2. Dainichiseika Kogyo) 54 parts dispersant (lecithin) 1 part carbon black
5 parts nitrocellulose
6 parts methyl ethyl ketone 2
70 parts of the above components were mixed, kneaded for 50 hours in a ball mill, further added with La part (Coronet), mixed for an additional 3 hours, passed through a filter to form a dispersion of magnetic particles (BD
I) was obtained.

Reference Example 21 (Preparation of Dispersion Liquid) A magnetic particle dispersion liquid (BD2) was obtained in the same manner as in Reference Example 20 except that a binder resin solution (BH3) was used instead of the binder resin solution in Reference Example 20. .

Reference Example 22 (Preparation of Dispersion Liquid) A magnetic particle dispersion liquid (BO2) was obtained in the same manner as in Reference Example 20 except that a binder resin solution (BH3) was used instead of the binder resin solution in Reference Example 20. .

Examples 1 to 3 The dispersion liquid UDI-UD3 obtained in the reference example was coated on a polyester film with a thickness of 15 pm using a reverse roll coater so that the thickness of each film was 5 gm,
After drying the solvent, the surface was processed using a super calendar roll and cut into a predetermined width to obtain magnetic recording media of the present invention.

Examples 4 to 6 Dispersions VDI to VD3 obtained in the reference examples were each applied to a 154 m thick polyester film using a reverse roll coater to a thickness of 51 Lm, and the solvent was dried. Thereafter, the surface was processed using a super calendar roll and cut into a predetermined width to obtain magnetic recording media of the present invention.

Examples 7 to 9 The dispersions BDI to BD3 obtained in the reference examples were each applied to a polyester film having a thickness of 15 gm using a reverse roll coater so that the thickness thereof was 5 μm,
After drying the solvent, the surface was processed using a super calendar roll and cut into a predetermined width to obtain magnetic recording media of the present invention.

Comparative Examples 1 to 3 Comparative magnetic recording media were obtained in the same manner as Examples 1 to 9, except that S-LEC A and S-LEC B, which were polyurethane resins that were not modified with the modifier of the present invention, were used.

Usage Example The performance of the magnetic recording media of the above Examples and Comparative Examples was investigated and the following results were obtained.

Incidentally, the coefficient of friction (A) is a value (ILk) measured between the magnetic layer and the support (base film).

Other performances were tested using a videotape, and
00 times of running (B), jitter lateral wobbling (C), irregular winding (CD) during fast forwarding of the tape, and abrasion of the magnetic layer (E). The overall evaluation was given as F.

・ABCDEF Comparative Example 10.52 Yes Yes Yes Yes Bad Example 10.22 No No No No Good Example 20.15 No No No No Good Example 30.10 No No No No Good Comparative Example 2
0.28 Slightly present None None Slightly present Slightly good example 40.
12 None None None None Good example 50.0
8 None None None None Good example 60.07
None None None None Good Comparative Example 30.32 Slightly Slightly Slightly Slightly Slightly Slightly Slightly Slightly Good Example 7 G, 1fll
None None None None Good example 80.11
None None None None Good example 90.10
None None None From the results of Good or better, it is clear that the magnetic recording medium of the present invention has a low coefficient of friction in the magnetic layer and exhibits excellent running characteristics.

Claims (2)

[Claims] (1) Consists of a non-magnetic support and a magnetic layer provided on one side of the support, where the magnetic layer is formed from a dispersion of magnetic particles, a binder resin, a modifier for the binder resin, and a medium. A magnetic recording medium, wherein the modifier is a reaction product of a fluorine compound having a reactive organic functional group and an organic polyisocyanate, and has at least one free isocyanate group. (2) The magnetic recording medium according to claim (1), wherein the binder resin has a group capable of reacting with an isocyanate group.