JPS5835729A - Magnetic recording medium - Google Patents

Abstract

PURPOSE:To improve adhesive property to a magnetic paint, by incorporating a sulfonic acid metallic salt derivative in a polyester film. CONSTITUTION:About 0.01-5wt% sulfonic acid metallic salt derivative expressed in general formula (where; R is alkyl group of 4-20 carbon numbers) is incorporated in a polyester film molding material, and after forming film with extrusion, biaxial orientation is done, thermal fixing is done at the range of 170-250 deg.C temperature to obtain a biaxial oriented polyester film having 1.375- 1.405 density. A magnetic paint is coated on a polyester film including this sulfonic acid metallic salt derivative to form a recording medium.

Description

Detailed Description of the Invention The present invention provides a magnetic recording material having good adhesion between a magnetic layer and a biaxially oriented polyester film (hereinafter simply referred to as "polyester film"). A material obtained by coating a polyester film on a polyester film is generally used. When a polyester film is used as a base for a magnetic recording medium, one of the essential characteristics of type 0 is excellent adhesion between the magnetic layer and the polyester film.

Conventionally, various methods have been attempted to improve the adhesion of both magnetic paints and polyester films, but no suitable method of improvement has been found.

The component that controls the adhesiveness between the magnetic paint and the polyester film is mainly the binder resin.

As binder resins, vinyl resins, fiber resins, urethane resins, epoxy resins, phenoxy resins, and the like are generally used.

For example, among the vinyl-based resins used for audio tapes, vinyl chloride-vinyl acetate is used as a magnetic paint.
As an improvement method from II, the type of binder resin was changed, and other second and third component resins were added.
There are many known examples of attempts to improve the adhesion with the preester film base by using additives, cross-linking agents, etc. However, the selection of the binder resin in magnetic paints is difficult. , maintains not only adhesion with polyester film, but also dispersibility of magnetic powder, high packing density, and high holding power.
Because it is required to satisfy characteristics such as electromagnetic conversion characteristics and abrasion resistance of the magnetic layer during repeated running, the polymers used by adding them to the main binder resin have their own limitations, and generally Binders for magnetic paints tend to be expensive.

On the other hand, as a method for improving the adhesion from the polyester film side, for example, a method is known in which polyester contains polyalkylene glycol to improve the adhesion with each cypress binder (Japanese Patent Application Laid-Open No. 117-117, Japanese Patent Application Publication No. Shoj/-?Oj!j). However, such films often have poor properties such as high strength, high Young's modulus, and low heat shrinkage properties required for magnetic tape base films, and therefore are not considered a preferred method.

Therefore, the present inventors have attempted to obtain a polyester film that has excellent adhesion to magnetic paint without impairing the mechanical strength, thermal dimensional stability, etc. inherent to polyester film.
As a result of repeated studies, the present invention has been completed.

That is, the present invention contains a sulfonic acid metal salt derivative and has a film density of 37! ~/, 4tOjb-, and exists in a magnetic recording body consisting of a biaxially oriented polyester film and a magnetic layer.

The present invention will be explained in more detail.

The polyester referred to in the present invention refers to terephthal I! Alternatively, it refers to a polyester obtained using its alkyl ester and ethylene glycol as main starting materials, but other third components may be used as part of the raw materials.

As the third component, as an aromatic dicarboxylic acid component, isophthalic acid, ・S7tale dicarboxylic acid #! In addition, O-alkyl esters or two or more types thereof may be used as glycol components, and polyalkylene glycols such as glypylene glycol, tetramethylene glycol, polyethylene glycol, etc. or two or more types thereof may be used. I can do it. In any case, polyester as used in the present invention means at least 1″O$ of repeating structural units.
refers to polyester that is ethylene terephthalate units.

Examples of the sulfonic acid metal salt-conductor used in the present invention include compounds having the structure shown below.

R-80, M・ , (1”) R
-0H=CH(OH,)ISOlMe ,,,,(■
) A preferable example is a decyl group.

Me represents an alkali metal or alkaline earth metal atom. 1, breath, and n represent an integer of / to 3.

Specific examples of the gold sulfonate h4@kasu conductor include Hiro, and examples of the alkyl sulfonate metal salt (1) include sodium octylsulfonate, sodium decylsulfonate, potassium dodecylsulfonate, sodium octadecylsulfonate, sodium tridecylsulfonate, Examples include magnesium tetradecylsulfonate.

As alkylbenzenesulfonic acid metal salt (II),
Examples include sodium dodecylbenzenesulfonate, potassium dodecylbenzenesulfonate, and sodium octadecylbenzenesulfonate. Alkylnaphthalene sulfonic acid metal salts (M) include dibutylnaphthalene, sodium phonate, and furkylaryloxyalkylene sulfone. Potassium pansulfonate, etc., is a historical friend.
- Sulfonic acid metal salt derivatives of olefins. Examples of the alkenesulfonic acid metal salt (It/) include sodium -monohexadecynylenesulfonate, and examples of the hydroxyalkanesulfonic acid metal salt (V) include,
Examples include sodium λ-human xyhexadecylsulfonate. Of course, these can be used alone, but a mixture of two or more strains may also be used.

In the present invention 1, the amount of the sulfonic acid metal salt derivative blended and dispersed in the polyester film is 0.0/
-j weight % is good, preferably 0.0-J weight %
be. If the amount of the sulfonic acid metal salt-conductor added exceeds 1 weight, it is not preferable because the mechanical properties and thermal properties of the polyester will be impaired. 0.0/weight attack) if it is less.

Adhesive reforming effect is insufficient.

In the production of a polyester film according to the present invention, the sulfone ridge metal salt derivative component can be added at any stage as long as it is before extrusion molding of the polyester resin to form a film. . For example, by directly tri-blending the polyester resin before extrusion molding, or by preparing a high-concentration masterbatch resin in advance, and mixing this with a polyester resin that does not contain a sulfonic acid metal salt derivative to a predetermined O content concentration. After dilution and mixing, it is also possible to extrude and form a film. Fi to produce high concentration master patch resin
, ! In addition to using the 1131-incorporating method, for example, it is convenient to add the compound after the transesterification reaction or esterification reaction is completed when producing polyester.

Of course, the timing of addition at this time is also not particularly limited.

The method for producing the polyester film of the present invention is not particularly limited, but may be performed by a conventional polyester film forming method such as the Chi-Dye method or the I-Dye method. Melt and extrude into a film at ℃, make an amorphous sheet, and then
It is possible to adopt methods such as sequential biaxial stretching or simultaneous biaxial stretching and heating at a predetermined temperature. the law of nature! ~/, *Oj N/-. The density is 7. j 771Ad), the resulting polyester film has poor thermal properties.

On the other hand, if the density exceeds /-4X Oj I/al, the mechanical properties O will drop significantly, which is undesirable.

Reduce the density of the film to 32! ~1. In order to obtain the desired OI, a biaxially stretched film may be heat-set in a temperature range of usually 0 to 210°C.

. The magnetic paint referred to in f# of the present invention means a paint in which, in addition to magnetic powder and a binder resin, a plasticizer, a 111 lubricant, a dispersant, an antistatic agent, etc. are mixed and dispersed as necessary. Binder resins include the above-mentioned vinyl resins, cellulose resins, urethane resins, epoxy 11rir, phenoxy resins, etc., but in particular, the polyester film of the present invention
Urethane resin as a binder component! Effective for magnetic coatings for video tapes containing fat.

There is no particular limit to the thickness of the polyester film, but
A range of j to 30 μO is preferable.

The polyester film of the present invention exhibits excellent aS properties with photomagnetic paints, but if necessary, the film may be subjected to ultraviolet*A irradiation, electronic trick irradiation, corona discharge treatment, plasma or arc discharge treatment as pretreatment before application. Other surface treatments may also be applied.

Next, on the polyester film, a magnetic paint made by the omniscient method # (e.g., Japanese Patent Application Laid-Open No. 2003-100002) is applied, dried, and aged to create a magnetic coating on the film. layer,
Allows tube formation. Magnetic paints are made by mixing, for example, magnetic iron oxide, especially r-Fes, os or cobalt doped with preservatives such as binder resin, dispersant and lubricant, and then adding a suitable solvent. In addition, 11II is manufactured.

The thickness of the magnetic layer after drying is approximately jμ.

The thus obtained magnetic recording material has excellent adhesion between the magnetic layer and the polyester film, and does not impair the original physical properties of the polyester film], and is suitable for audio, video, etc. Suitable for use as a gas recording medium.

EXAMPLES Hereinafter, the present invention will be explained in more detail with reference to Examples.

In addition, parts and % in the examples are parts by weight and % by weight, respectively.
shows.

The methods for measuring and evaluating the main characteristics in the present invention are shown below.

/ Adhesive strength between the magnetic layer and the base film: A double-sided adhesive is pasted on a stainless steel plate with a thickness of 1. After that, the polyester film is peeled off from the magnetic layer at an angle of 1. m by tensile testing machine;
n Measured at a speed of 1000 m/(turn). Adhesive strength is
It was expressed as a compensatory ratio to the adhesive strength of the film obtained from polyethylene tereftate homopolymer.

Using Toyo Bold Line's Tensilon UT, M-51 type, the temperature was 20℃ and the humidity was ≦! In the sample film of length jOw+, width ≦, -I.

jθ■/ Tensile at 4D speed) O load at J% extension is F
It was taken as the j value. Furthermore, the slope of the initial tangent line was read on the chart at a 7% elongation and the Dayang's modulus was calculated.

J Density in a mixed solution of n-hebutane and carbon tetrachloride = value measured by the float-sink method at j°C.

Example/ After addition and triblending, vacuum drying was performed at 741°C for 1 hour. The mixture was then kneaded using a scissors blend dry resin extruder to produce a masterbatch resin containing 1% tridecylsulfone iron sodium salt. Next, 10 parts of the master patch resin and part of the polyethylene terephthalate resin were triblended, air-dried at 141°C for 4 hours, melted at θ°C, extruded through a T-die, rapidly cooled, and vertically Stretched by 0 times in the direction, KJ, z times in the transverse direction, then heat-treated at -2-0℃ for 70 seconds to obtain a thickness of 0.
An axially oriented polyester film was obtained. The density of Jin's fill voice was 7.30.

For comparison, a biaxially oriented film was obtained using a polyethylene/tere-7 talenite homopolymer in the same manner.

Magnetic paint was applied onto these films by the method shown below.

(Preparation and application of magnetic paint) '-'%Os 2B! d
'7 Polyurethane resin To part Unitrocellulose Cos Polyvinyl chloride-vinyl acetate copolymer 30 parts Methyl ethyl ketone 900 parts The above components were stirred and dispersed together in a ball mill for 0 hours, and then 71 parts of isocyanate was added. A magnetic paint was obtained by ball milling for 10 minutes. This magnetic paint was coated on the previously prepared biaxially oriented polyester film using a coater so that the dry film thickness was approximately Jμ, then dried at to°C for 7 minutes, and then cooled for 10 minutes. Aged for yoo at ℃. after that,
This coated film was cut to a width of /J and 7 lengths in the direction of application of the magnetic paint, and used for measuring adhesive strength.

The results are shown in Table 1.

Practical example = Ethylene glycol slurry of terephthalic acid with a molar ratio of ethylene glycol to terephthalic region of 8/I,
Esterification reaction rate left in the reaction tank in advance? 7
% of the varnish/chilled reaction product and the esterification reaction was carried out by a batch method.The esterification reaction rate was 97% and the number average degree of polymerization was 97% at the time of zero reaction. Approximately 1 liter of the obtained esterification reaction product was subjected to a hot plate condensation reaction, and the remainder was ladlered and used for the esterification reaction of the next batch. , pn σ, 0/@, polycondensation reaction was carried out by adding 0.0 part of antimony triplet, 1% of tetrazocursulfone dissolved sodium chloride, polyethylene terre 7 tarley) 411jli Get it.

Then the ζO polymer 71I and the sulfone chain metallization t
A polyester film having a thickness of lJ was obtained in the same manner as in Example F41 by blending VI and polyethylene terephthalate. Magnetic paint was applied in the same manner as in Detailed Example 1, and the vibration resistance was #F-.

Luken O sulfone-related sodium clay and human sialkane sulfone sodium trichloride were obtained. 0.2 parts of the reaction product was added to 100 parts of polyethylene terephthalate resin, and extrusion stretching and hot salting were performed to obtain a polyester film having a thickness of /jμ. A magnetic paint was also applied to the cough film in the same manner as in Example 1, and the adhesion between the magnetic layer and the polyester film was evaluated. The results are shown in Table 1.

Example! 10 parts of polyethylene terephthalate and 0 parts of sodium dobuclebenzene sulfonate. In the same manner as in Example 1, a Bolier-Ichiru film was prepared by directly blending with J @ and the adhesion between the magnetic layer and the film was evaluated in Example D. Example J is an example of blending the parts.
It was shown to.

The results are shown in Table #I1.

As is clear from the above results, the polyester film containing the sulfonic acid metal salt derivative according to the present invention has extremely excellent adhesion to magnetic paint even when added in a small amount, and also has magnetic recording It does not have any negative effect on the thermal and mechanical properties required for body-use base films, and in some cases even has the previously known antistatic effect, making them even higher. It is useful as a base film for high quality magnetic recording media.

7/ /″゛7.-・″ , 7/ * The relative adhesive strength ratio is the adhesive strength i/ of a film made of polyethylene tere-7-thalerate homopolymer that does not contain sulfonic acid gold salt, i/, 0. Expressed as a relative ratio of hours.

Sender: Diafoil Co., Ltd. 150-

Claims (1)

[Claims] (1) A magnetic recording material comprising a biaxially oriented polyester film containing a sulfonic acid metal salt derivative and having a film quadrature of 8371 to /J Oj 11/lxJ and a magnetic layer.