JPS6116021A - Film for magnetic recording - Google Patents

Abstract

PURPOSE:To improve the adhesiveness to a substrate and to obtain excellent running property by forming a coated film of an aq. dispersion consisting of a specific water insoluble polyester copolymer, water soluble org. compd. and water on a polyester film surface and providing a coated film contg. a lubricant thereon. CONSTITUTION:The coated film is formed on the polyester film surface by using the aq. dispersion of the polyester resin which consists essentially of A) the water soluble polyester copolymer consisting essentially of the residual group of the mixed dicarboxylic acid in which 0.5-15mol% in the total dicarboxylic acid component is dicarboxylic acid contg. sulfonic acid metallic salt, B) the water soluble org. compd. having 60-200 deg.C b.p. and C) water and is compounded with A/B=100/(20-500), B/C=100/(50-10,000) ratio by weight and the coated film is further formed on the coated film by a paint dispersed therein with the lubricant. The adhesiveness of the magnetic layer is improved by coating such primer coating layer on the substrate. The running property is improved without decreasing S/N by providing the coated film dispersed therein with the lubricant on another surface.

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention relates to a magnetic recording film, which has a magnetic layer on one side, a coating film for improving the adhesion to the film substrate, and the other side has a magnetic layer. It is an object of the present invention to provide a magnetic recording film formed with a coating film in which a lubricant is dispersed in order to lower the coefficient of friction and improve running properties without lowering the coefficient of friction (8,/N).

<Relationship with Prior Art> In general, the surface of a base film of a magnetic recording tape for audio, video, or computer use is finished to be smooth in order to improve the magnetic recording sensitivity of the tape. However, such a smooth magnetic recording tape is not properly monitored when it is being unrolled and rewound, and is prone to unbalanced state. Using magnetic tape like this 2)
Driving performance becomes poor due to tension and camera movements, and output fluctuates.
Tape deformation and scratches are also likely to occur.

On the other hand, in response to the improvement in the performance of magnetic recording, efforts are being made to increase the packing capacity of magnetic powder books. However, when the packing density of the magnetic powder is increased, the adhesion of the magnetic layer to the base film tends to deteriorate and the strength of the coating film tends to decrease.

<Objectives of the Invention> In view of these circumstances, it is an object of the present invention to provide a magnetic recording film that has good running properties and excellent adhesion of the magnetic layer to the base film.

<Structure of the Invention> The present invention is characterized in that residues of a mixed dicarboxylic acid, which is a dicarboxylic acid containing 0.5 to 15 mol % of a dicarboxylic acid group and a glycol, are added to at least one side of a polynitrile film. A water-insoluble polyester copolymer whose main component is CB) a water-soluble organic compound at 150 to 200°C and (C) water, and (A)/(B) = 100/20 to 5000 , (B) /
A film is formed from an aqueous dispersion of polyester resin blended in a weight ratio of (C)=10Q150 to 10,000, and a coating film with a lubricant dispersed in the coating material is formed on one side of the coating film. The inventors have discovered that this film has excellent adhesion to the magnetic layer and excellent running properties.

The polynisder copolymer (A) contained in the aqueous dispersion of this invention is a dicarboxylic acid containing a sulfonic acid metal group.
Substantially water-insoluble polyester copolymer obtained by reacting a mixed dicarboxylic acid with a polyol component, such as 5 to 15 mol %, and 85 to 99.5 mol % of a dicarboxylic acid containing a sulfonic acid=mm group. It is a combination. Substantially water-insoluble means that the polyester copolymer does not dissipate in hot water even if the polyester copolymer is stirred in hot water at 80°C. 80 of
'C.

The weight loss of the polyester copolymer after being stirred in 18 water for 24 hours is 5 weight 1f% or less.

The above-mentioned sulfonated metal f & (group-containing dicarboxylic acids include sulfoterephthalic acid, 5-sulfoisophthalic acid,
-sulfophthalic acid, 4-sulfonaphthalene-2,7-dicarboxylic acid, 5[4-sulpophenoxy]isophthalic acid, etc., and particularly preferred are Get 5-sodium sulfoisophthalic acid, sodium It is sulfoterephthalic acid. These sulfone heavy metal @ group-containing dicarboxylic acid components are contained in an amount of 0.5 to 0.5 to
The content is 15 mol%, preferably 2.0 to 10 mol%. If it exceeds 15 mol%, the water dispersibility will improve, but the water resistance of the polyester copolymer will be markedly reduced, and if it is less than 0.5 mol%, the water dispersibility will drop significantly. The dispersibility of the polyester copolymer in water varies depending on the copolymer composition, the type and blending ratio of water-soluble organic compounds, etc., but the dicarboxylic acid containing the sulfonic acid metal group may be used in small amounts as long as the dispersibility in water is not impaired. That is preferable.

Dicarboxylic acids that do not contain sulfonic acid metal bases include:
Aromatic, alicyclic, and aliphatic dicarbons tfP can be used. Examples of aromatic dicarboxylic acids include terephthalic acid, isophthalic acid, orthophthalic acid, and 2°6-naphthalenedicarboxylic acid. It is preferable that these aromatic dicarboxylic acids account for 40 mol% or more of the total dicarboxylic acid components, and if it is less than 40 mol%, the mechanical strength and water resistance of the polyester copolymer will decrease. Aliphatic and fatty T
RM dicarboxylic acids include succinic acid, adipic acid,
Sebacic acid, t, a-shika [2nd floor of J Pentales Carbo,
1.2-cyclohexanedicarboxylic 6y, 1 + 3
-Cyclohexanedicarboxylic acid, rubonic acid, 1,4-cyclohexanedicarboxylic acid, and the like. Addition of these non-aromatic dicarboxylic acid components may improve adhesive performance in some cases, but generally reduces the mechanical strength and water resistance of the polyester copolymer.

The polyol component to be reacted with the mixed dicarboxylic acid is an aliphatic glycol having 2 to 8 carbon atoms or an alicyclic glycol having 6 to 121 carbon atoms, specifically, ethylene glycol, 1,2-propylene glycol, etc. , 1,3-propanediol 1,4-butanediol, Ne-opentyl glycol 1,6-hexanediol, 1,2-cyclohexane dimetatool, 1,3-cyclohexane dimetatool, l,4-cyclohexanediol These include metatool, P-xylylene glycol, diethylene glycol, triethylene glycol, and the like. Examples of polyethers include polyethylene glycol, polypropylene glycol, and polytetramethylene glycol. Further, an oxycarboxylic acid component such as P-oxyethoxybenzoic acid may be copolymerized.

Polyester copolymers are obtained by conventional melt polycondensation. In other words, the above dicarboxylic acid component and the glycol component are directly reacted, water is distilled off and esterified, and then polycondensation is performed. It can be obtained by a transesterification method in which alcohol is distilled out, transesterified, and then polycondensed. In addition, solution polycondensation, interfacial polycondensation, etc. may also be used, and the polyester copolymer of the present invention is not limited by the polycondensation method.

During melt polycondensation, antioxidants, slip agents, inorganic fine particles, antistatic agents, and the like can be added as appropriate.

To obtain the aqueous dispersion of the above polyester copolymer,
It is necessary to disperse it in water together with water-soluble organic compounds. For example, the above polyester copolymer and a water-soluble organic compound are mixed in advance at 50 to 200°C, and water is added to this mixture and dispersed by stirring, or conversely, the mixture is added to water and dispersed by stirring. Alternatively, there is a method in which a polyester copolymer, a water-soluble organic compound, and water are mixed together and stirred at 40 to 120°C.

The above-mentioned water-soluble organic compound is an organic compound having a solubility in water of 16 to 202 or more at 20°C, and specifically includes aliphatic and alicyclic alcohols, ethers, esters, and ketone compounds, such as methanol, ethanol, Improper tool, monohydric alcohols such as n-butanol,
These include glycols such as ethylene glycol and propylene glycol; glyfur derivatives such as methyl cellosolve, ethyl cellosolve, and n-butyl cellosolve; ethers such as dioxane and tetrahydrofuran; esters such as ethyl acetate; and ketones such as methyl ethyl ketone. These water-soluble organic compounds can be used alone or in combination of two or more. Among the above compounds, butyl cellosolve and ethyl cellosolve are preferred in terms of dispersibility in water and coatability on films.

The above (g) polyester copolymer, ([3) water-soluble organic compound and (C) water blend type 1kk ratio is (5)/
(Iυ=100/20~5000(B)/(C)=1
It is important to satisfy the range of 00/50 to 10000. When the amount of water-soluble organic compounds is small compared to the polyester copolymer and (A)/(B) exceeds 100/20,
The dispersibility of the aqueous dispersion decreases. In this case, dispersibility can be improved by adding a surfactant, but if the amount of surfactant is too large, adhesiveness and water resistance will decrease. Conversely, if <A)/(B) is less than ioo/5ooo, or if (B)/(C) exceeds ioo,,'50, the amount of water-soluble organic compounds in the aqueous dispersion increases and melts. During so-called in-line coating, in which an extruded unstretched film or uniaxially stretched film is coated with an aqueous dispersion of the polyester resin and then stretched, there is a risk of explosion due to the solvent, and for this reason, it is necessary to take shore protection measures.
Furthermore, it is necessary to consider recovery of the compound since it causes environmental pollution and increases costs. (B) / (C) is 100/100
If it is less than 00, the surface tension of the aqueous dispersion increases, the wettability to the film decreases, and coating spots are likely to occur. In this case, the marking property can be improved by adding a surfactant, but if the fit of the surfactant is too large, the adhesion and water resistance decrease as described above.

A slip agent, an antistatic agent, an anti-blocking agent, a crosslinking agent, etc. may be added to the above aqueous dispersion.

The polyester film to which the aqueous dispersion of the polyester copolymer (5) is applied is a melt-extruded unstretched film, a uniaxially stretched film, or a biaxially stretched film; in the case of an unstretched film or a uniaxially stretched film. is made into a biaxially stretched film by applying an aqueous dispersion of polyester resin and then stretching the film.

The amount of the aqueous dispersion applied to the polyester film is 0.01 to 5 f/rr as the polyester copolymer to the film after biaxial stretching. is preferred. If the coating amount is less than 0.01 t/m", the adhesion of the magnetic material layer provided on the polyester copolymer layer is insufficient. If the coating amount exceeds 5f/rr?, the polyester film machine In addition, as the copolymerized polyester resin in the recovered and recycled film increases, the mechanical strength and heat resistance of the recycled film deteriorate.

If the polyester film is subjected to corona discharge treatment before applying the aqueous dispersion of the polyester resin mentioned above, the applicability of the aqueous dispersion will be improved and the adhesive strength between the polyester film and the polyester copolymer coating will be improved. This is a preferred embodiment because it improves the performance.

In addition, by subjecting the polyester copolymer layer to corona discharge treatment, corona discharge treatment under a nitrogen atmosphere, ultraviolet irradiation treatment, etc., a magnetic layer or a coating film with a lubricant dispersed therein can be formed. It is possible to improve iM resistance and adhesiveness.

The lubricant dispersed in the coating film formed on one side of the polyester copolymer layer coating film includes tungsten disulfide, molybdenum disulfide, boron nitride, 5iOz, CaCO3, AI 20+1, Fe.
2O3, TlO2, MgO, ZnO, CaO, 5nOz
, BaSO4, etc. Among the above, 5102, Ca
CO3, TlO2, and Ba50n are preferred, and CaC0a and Ba5Oi are particularly preferred. When using these lubricants, particular attention must be paid to their size and hardness. The average particle size is preferably 0.02 to 0.5 μm, particularly preferably 0.02 to 0.5 μm. It is preferable that the inkstone has a Mohs hardness of 2.5 or more. The amount of these lubricants used is o, i to 4.0, preferably 0.1 to 2.5, particularly preferably 0.5 to 1, in weight ratio to the binder.
．． It is 5.

As the binder used at the same time, for example, a thermoplastic resin, a thermosetting resin, a reactive resin, or a mixture thereof is used, but as the dicarboxylic acid component of the copolyester resin used in the present invention, , aromatic dicarboxylic acids such as terephthalic acid, isophthalic acid, orthophthalic acid, and 1,5-7thalic acid, aromatic oxycarboxylic acids such as p-oxybenzoic acid, p-(hydroxyethoxy)benzoic acid, and succinic acid. acid, aliphatic dicarboxylic acids such as adipic acid, azelaic acid, sepacic acid, dodecanedicarboxylic acid, etc., but the molar ratio of the aromatic dicarboxylic acid component and the aliphatic dicarboxylic acid component is 50,150 to 10.
0/0, and preferably at least 30 mol% of the aromatic dicarboxylic acid component is terephthalic acid. Small amounts of tri- and tetracarboxylic acid components such as trimellitic acid, trimesic acid, and pyromellitic acid may be used in combination.

The glycol components that react with the dicarboxylic acid include ethylene glycol, propylene glycol, 1.3
-Pripanediol, 1.4-butanediol, 1.5
-bentanediol, 1,6-hexanediol, neopentyl glycol, diethylene glycol, dipropylene glycol, 2,2,4-trimethyl-1,3-bentanediol, 1,4-cyclohexane dimetatool, ethylene oxide of bisphenol A Adducts and propylene oxide adducts, ethylene oxytoy\J adducts of hydrogenated bisphenol A and propylene oxide adducts include polyethylene glycol, polypropylene glycol, polytetramethylene glycol, and the like.

Small amounts of tri- and tetraols such as trimethylolethane, trimethylolpropane, glycerin, and pentaerythritol may be used in combination. Further, an oxycarboxylic acid component such as P-oxyethoxybenzoic acid may be copolymerized.

The dicarboxylic acid component containing a sulfonic acid metal base that characterizes the copolymerized polyester resin) includes 5-sodium sulfoisophthalic acid, 5-potassium sulfoisophthalic acid, 2-sodium sulfoterephthalic acid, 2-potassium sulfoterephthalic acid, etc. The copolymerization amount of the 19 dicarboxylic components containing these sulfonic acid gold BS bases is 0.3 to 70 mol% based on the total dicarboxylic acid components.
It is preferably 1.0 to 5.0 mol%. If the copolymerization amount is less than 0.3, the performance improvement will not be sufficient, and
If the copolymerized needle exceeds 7.0 mol%, the copolymerized polyester will have poor solvent solubility and will be impractical.

These copolyester resins are particularly effective in improving the dispersibility of lubricants and in improving the adhesion to polyester films. The copolymerized polyester resin is used in an amount of 5% or more of the total binder, preferably 10% or more.

Other binders to be added include vinyl chloride-vinyl acetate copolymer, vinyl chloride-vinylidene chloride copolymer, vinyl chloride-acrylonitrile copolymer, acrylic ester-acrylonitrile copolymer, and acrylic ester-acrylonitrile copolymer. Polymer, acrylic ester-vinylidene chloride co-A (combined, acrylic ester-
Styrene copolymer, methacrylic acid ester-acrylonitrile copolymer, methacrylic acid ester-vinylidene chloride copolymer, methacrylic acid ester-styrene copolymer, urethane elastomer, polyvinyl fluoride, vinylidene chloride-acrylonitrile copolymer Polymers, phthalene copolymers, polyamide resins, polyvinyl butyral, cellulose resins (cellulose acetate butyrate, nitrocellulose, cellulose diacetate, cellulose propioate, etc.), styrene-butadiene copolymers,
Chlorovinyl ether-acrylic Bl Nisdell copolymer, amino pine resin, phenol resin, epoxy resin, polyurethane, 4-stem resin, urea resin, melamine ji', resin, alkyd resin, acrylic reaction resin, polyisocyanate, polyamine and so on.

If the softening point of the copolymerized polyester 4 (grease-resistant) is low, depending on the use, there is a risk that it will soften due to the heat between it and the heel, or that it will block when wrapped with tape. For such 11-polymerization, it is desirable to mix a compound which is compatible with the copolyester resin within a range that does not impair the dispersibility of the lubricant particles and which reacts and crosslinks. Blend-1 is generally 2 to 1011 parts per 100 parts by weight (it part) of the copolymerized polyester resin.

Examples of such compounds include epoxy resins, incyanate compounds, and melamine resins.

Among these, isocyanate compounds are particularly preferred.

Copolymerized polyester resin obtained in this way (4)
, utilizing the terminal group of (2) to form a difunctional incyanate compound, such as 2,4 tolylene diisocyanate, 2.6
1li1i with tolylene diisocyanate, diphenylmethane diisocyanate, xylene diisocyanate, inphorone diisocyanate! A polymer subjected to an extended reaction can be used. This method allows two types of copolymerized polyester resins to be combined to take advantage of their characteristics. That is, this is a preferred embodiment because the introduction of urethane groups can improve the adhesion to polyester films, increase the solvent solubility of the copolymerized polyester resin, and improve the water resistance of the coating film.

Although various films have been proposed as base films for magnetic recording media, polyester films are superior in terms of mechanical properties, chemical resistance, heat resistance, etc. Among them, polyethylene terephthalate films are 18
Outstanding in terms of 8 qualities.

The surface roughness of the undercoat autopsy cloth surface and the anti-coating surface of this polyester film is very important for reducing noise and preventing signal dropouts in the production of magnetic recording media. Measured using a roughness meter (manufactured by Tokyo Seimitsu) under the conditions of a needle diameter of 1 μm, a load of 0.07 f, a measurement reference length of 0.8 mm, and a cutoff of 0.08 mm) is preferably 0.05 μm or less, and 0.05 μm. If it exceeds this, noise and signal loss will occur, causing problems in use.

In addition, the surface roughness of the coating film in which the lubricant is dispersed is very important in order to reduce noise and prevent signal loss when used as a magnetic tape because the unevenness on the coating surface is transferred to the magnetic layer.
Center line average roughness (RA) (Using a Surfcom 300A surface roughness meter (manufactured by Tokyo Seimitsu), needle diameter 1 μm 1 weight 0.07
t, measurement reference length 0.8 mm.

(measured under the condition of a cutoff of 0.08 m) is preferably 0.03 μm or less, and if it exceeds O.Oa μm, noise and signal loss will occur, causing problems in use.

In the magnetic recording film of the present invention, additives such as carbon blank powder and graphite can be added to the coating film in which a lubricant is dispersed for antistatic purposes.

<Effects of the Invention> As described above, when the film obtained by the present invention is used for magnetic recording, it has excellent R'f contact with the magnetic layer, has a low coefficient of friction during running, and has excellent running durability. It has the effect of being

<Examples> In the following, the present invention will be explained in detail by way of examples. In the 8 examples, "parts" simply refer to "heavy" parts. In the adhesion test (Beerback method), adhesive tape was applied to the surface of the magnetic layer evenly over the entire surface, and then the state was observed when it was peeled off at intervals. The portion where the magnetic layer remains is 95% or more of the total area ◎, 50 to 95% is 0.10 to 50% △
, 10% or less is indicated by ×. In the running durability test, the tape was run 100 times on a VHS video deck.
The coefficient of dynamic friction (at a running speed of 3, 3 m/sec) of the coated film side in which the lubricant was dispersed was measured for the virgin tape that was not run.

Reduced viscosity 1 eap/C (dt/f) is obtained by dissolving polyester resin &o,
It was measured with

The softening point was determined according to JI 52351.

In the examples, magnetic tape was formed on the undercoat layer as follows.

Magnetic paint Co-Fe (3-nea) alloy fine particles 300 parts (
Average diameter 0.02 μm) Acrylonitrile/Butyl acrylate/Methacryl
30 parts 2-hydroxyl acid (=90/190/20) Palm M50% modified alkyd resin 35 parts silicone oil 2 parts butyl acetate
700 parts of the above paint was put into a ball mill and kneaded for 12 hours, then 22 parts of Furonate L (manufactured by Nippon Polyurethane Co., Ltd.) as a polyisocyanate compound was added.
A magnetic paint was obtained by high-speed shear dispersion for 1 hour. This paint 3
It was applied onto a polyethylene terephthalate film having a thickness of 25 microns, which had been filtered through a filter having an average pore size of microns to form an undercoat layer, and dried by heating to a dry thickness of 3 μm.

The magnetic tape thus obtained was calendered and slit into 1/2 inch width to obtain a videotape.

Example 1 (1) Production of aqueous dispersion of polyester copolymer (4) 117 parts (49 mol%) of dimethyl terephthalate, 117 parts (49 mol%) of dimethyl isophthalate, 103 parts (50 mol%) of ethylene glycol, Diethylene glycol 58 parts (50 mol%), vinegar mzinc 0.08 part, antimony trioxide O, OS part were added in a reaction vessel at 40 to 220°C.
The temperature was raised to
119 parts (2 mol %) of sodium sulpoisophthalate was added, and the mixture was subjected to an esterification reaction at 220 to 260°C for 1 hour, and then a polycondensation reaction was performed for 2 hours under reduced pressure (10 to 0, 2 mrnHy) to obtain an average molecular flk of 18,000. A polyester copolymer having a softening point of 140°C was obtained. 300 parts of this polyester copolymer and 1 part of n-butyl cellosolve
40 parts of water was pressed with fingers in a container at 150 to 170°C for about 3 hours to obtain a homogeneous and viscous melt, and 56 parts of water was added to this melt.
After about 1 hour, a uniform pale white aqueous dispersion with a solid content concentration of 30% was obtained.
Dilute with 4500 parts of ethyl alcohol to remove solids.
A 3% coating solution was obtained once.

(2) Production of coated film Polyethylene terephthalate is melt extruded at 280 to 300°C, cooled with a cooling roll at 17.15°C to obtain an unstretched film with a thickness of 130 microns, and this unstretched film is extruded at different circumferential speeds at 85°C. The film was stretched 3.5 times in the machine direction between a pair of rolls, and the -axially stretched film was subjected to a corona discharge treatment.
The above-mentioned coating solution was applied to the discharge-treated surface of L + C and C4 using an air knife method, dried with hot air at 70°C, then stretched 3.5 times in the M direction at 98°C with a tenter, and further stretched to 200°C.
~210t1. A biaxially oriented coated polyester film with a diameter of 5 and 12 microns was heat-set at a temperature of 100 mm. (Undercoating process: in-line) (3) Production of copolyester resin for coating film containing lubricant dispersion In a reaction vessel equipped with a thermometer, a stirrer, and a partial reflux type cooler, 175 parts of dimethyl terephthalate and dimethyl isophthalate were added. 78 parts, 161i of ethylene glycol, 145i of neopentyl glycol, 14.8 parts of dimethyl 5-sodium sulfoisophthalate, 0.17 parts of zinc acetate,
0.02 part of aluminum acetate and 0.16 part of antimony trioxide were added, and transesterification reaction was carried out at 140 to 220°C for 3 hours. Next, add 13) parts of sebacic acid and add 2 parts of sebacic acid.
After reacting at 10 to 250°C for 1 hour, the reaction system was depressurized to 1 to 5 mHy over 60 minutes, and further heated to 0 at 250°C.
The polycondensation reaction was carried out for 60 minutes under reduced pressure of , 1 to 0, 3 ttaaHy. The obtained copolymerized polyester resin (
D) had a softening point of ηsp/C=(C63) of 113°C and was pale yellow and transparent. NMR (nuclear magnetic resonance) analysis revealed that its composition was as follows: Phthalic acid
45 mol-Isophthal 1 yield
2゜Sebacic acid 32
．． 55-Sodium sulfoisophthalate 2.5 Ethylene glycol 5゜Neopentyl glycol 5゜(4
) Ability to form coating film containing lubricant dispersion Copolymerized polyester Wk) 50g Vinyl chloride vinyl acetate copolymer 5 parts (manufactured by Denki Kagaku Kogyo Co., Ltd.) Nitrocellulose 10 parts Polyisocyanate 15 parts (Coronate L: Nippon Polyurethane Co., Ltd.) A cross-dispersion of 370 parts of CaC (average particle size: 0.05 μm) was applied onto the biaxially stretched coated polyester film with a thickness of 12 μm obtained in (2) above, and the thickness of the coating film after drying was is set to 1 micron.

Example 2 'In Example 1, 1 DEG in the composition of the primer
A film for ω-signature (1) was obtained in the same manner as in Example 1 except that the lubricant dispersion was changed to PEG and the binder composition in the lubricant dispersion @ film composition was changed.

Examples 3 to 4 Actual Bm Example 3 was prepared in the same manner as Example 2 except that the binder composition in the lubricant-dispersed coating film composition was changed in Example 2, and the type of lubricant in Example 4 was changed to 8102. Got the film.

Comparative Example 1 A magnetic recording film was obtained in the same manner as in Example 1 except that the undercoating step was not performed.

Comparative Example 2 A magnetic recording film was obtained in the same manner as in Example 1 except that the lubricant-dispersed coating film was not formed in Example 1.

Comparative Example 3 A magnetic recording film was obtained in the same manner as in Example 1, except that in Example M1, the amount of 5-sodium sulfoisophthalic acid as an undercoat was changed to 20 parts %.

Comparative Example 4 A magnetic recording film was obtained in the same manner as in Example 2 except that the copolyester resin was not added to the lubricant-dispersed coating film.

Comparative Example 5 Demonstrated the properties of an untreated polyester film without the formation of both an undercoat and a lubricant dispersion coating.

From Table 1, compared to the comparative example, the present invention has a magnetic layer contact with the base film of 4'I/1. It can be seen that the performance is good and the running performance is also very good.

Claims (7)

[Claims] (1) (A) on at least one side of the polyester film
A water-insoluble polyester copolymer whose main components are residues of a mixed dicarboxylic acid and glycol residues, in which 0.5 to 15 mol% of the total dicarboxylic acid components are dicarboxylic acids containing sulfonic acid metal bases, (B) boiling point 60 The main components are a water-soluble organic compound at ~200°C and (C) water, and (A)/(B)=100/20-5000, (B)/(
C) A coating film is formed from an aqueous dispersion of polyester resin blended in a weight ratio of 100/50 to 10,000, and a lubricant is dispersed in the coating material on one side of the coating film. A magnetic recording film with a coating formed on it. (2) At least one component of the coating used in the coating film in which the lubricant is dispersed has (D) a reduced viscosity of 0.1 or more;
Claim 1, which is a polyester resin whose main components are residues of a mixed dicarboxylic acid in which 0.3 to 7.0 mol % of the total dicarboxylic acid components are dicarboxylic acids containing sulfonic acid metal bases and residues of glycol. The magnetic recording film described in Section 1. (3) The magnetic recording film according to any one of claims 1 to 2, wherein the polyester film is a film made of polyethylene terephthalate. (4) Center line average roughness (R
The magnetic recording film according to claims 1 to 3, wherein _A) is 0.05 μm or less. (5) Center line average roughness of the coating surface with lubricant dispersed (
Claim 1 in which R_A) is 0.03 μm or less
A magnetic recording film according to items 1 to 4. (6) The magnetic recording film according to any one of claims 1 to 5, wherein the water-insoluble polyester copolymer (A) is a polymer chain-extended with a diisocyanate compound. (7) The magnetic recording film according to any one of claims 1 to 6, wherein the polyester resin (D) is a polymer chain-extended with a diisocyanate compound.