KR20070052975A - A method making magnetic stripe - Google Patents

Abstract

The present invention relates to a method of manufacturing a magnetic stripe to form a magnetic layer on a nonmagnetic support. Specifically, the addition of a binder having one or more functional groups improves dispersibility of the magnetic coating, thereby improving productivity, magnetic output, The present invention relates to a magnetic strip having excellent durability, stability of storage, and the like.

Magnetic material, binder with one or more functional groups, hardener, carbon black, lubricant

Description

A method of making magnetic stripe

The present invention relates to a method of manufacturing a magnetic stripe to form a magnetic layer on a nonmagnetic support. In general, magnetic recording media are used in various ways such as magnetic tapes, floppy disks, subway tickets, credit cards, telephone cards, as well as information recording media such as passbook stripes, amusement park passes, and identification cards. .

In a method of manufacturing a magnetic recording medium made of a magnetic strip or the like, a magnetic layer is formed by applying a magnetic paint on a nonmagnetic support having a wider area than a conventional product, followed by orientation treatment or the like to form a disc of the magnetic recording medium. The magnetic layer can be added to the surface smoothing process as needed. Thereafter, the final product is finished through a slitting process in order to cut to a certain width suitable for the purpose of use after the curing process. As a final process, the magnetic strip, which is the final product of the next step, may be made through a process such as size processing.

The magnetic coating is prepared by mixing and dispersing other inorganic materials such as ferromagnetic powder and alumina carbon black, and a lubricant, a curing agent, and a dispersant in a binder solution, and the surface smoothing treatment is required to improve the smoothing and filling density of the surface of the magnetic layer. When present, it is possible to achieve uniformity of coating thickness during application and process application. The smoothing of the surface of the magnetic material is very effective for the improvement of the reproduction output of the magnetic recording medium and the reduction of the miscellaneous signal. The magnetic paint used to manufacture such a magnetic recording medium is generally provided through detailed processes such as kneading, first dispersion, second dispersion, filtration, and kneading. Low molecular materials such as phosphoric acid and amine are used as dispersants to improve the dispersibility of magnetic paints. Since the time spent in the mixing and dispersing process, which is the manufacturing process of magnetic paint, accounts for more than 50% of the time required for the entire process, it can be called a process that greatly affects the productivity of the product. Dispersibility is improved, but surface damage may be caused by deterioration in durability, coating strength, density and surface property of information recording.

Therefore, an object of the present invention is to solve the above problems, the dispersion characteristics of the magnetic coating is very excellent, and to form a magnetic layer having a high filling rate required recording of short wavelength and inversion of magnetization in the local, as well as the influence of the nonmagnetic support The present invention provides a method of manufacturing a magnetic strip, which is a high-quality magnetic recording medium having excellent magnetic properties such as high density recording, and particularly excellent electron conversion characteristics, without recording loss and surface damage.

In order to achieve the above object, the present invention is a method of manufacturing a magnetic strip to form a magnetic coating on a nonmagnetic support by applying a magnetic paint on a nonmagnetic support, the binder used in the magnetic coating is one or more functional groups Also included is an average glass transition temperature of 45 ℃ to 70 ℃, provides a method of producing a magnetic strip that the glass transition temperature of the magnetic layer after the curing reaction is completed after addition of the curing agent is 80 ℃ or more. When the average glass transition temperature of the binder is low, the surface property inside the winding is changed due to the pressure of the roll wound during curing after drying, which leads to a decrease in durability due to an increase in the coefficient of friction. Acidity is reduced. If the average glass transition temperature of the binder is high, the flexibility of the coating film is lowered, causing problems such as cracking of the surface. Moreover, when the glass transition temperature after hardening is low, adhesion phenomenon may arise or the lifetime at the time of repeated use may fall because of durability fall.

The present invention is described in more detail as follows. A common magnetic strip is prepared by forming a magnetic layer coated with a magnetic coating solution prepared by dispersing ferromagnetic powder in a binder solution containing one or more functional groups on a nonmagnetic support, wherein the thickness of the magnetic strip is 75 μm or less. Is applied. Therefore, the conventional tape is a magnetic layer that is repeatedly used to produce a magnetic strip by using a polymer material such as polyethylene terephthalate having a thickness of the nonmagnetic support in the range of 48 to 52 μm and applying or depositing a magnetic layer of 13 to 25 μm thereon. In the present invention, the magnetic layer of the magnetic strip is formed to be thinner to improve the durability of the coating film, so that the magnetization can be reversed locally, thereby improving recording efficiency and reducing cost through productivity and material cost reduction. To this end, the magnetic layer can be formed by improving the durability of the magnetic layer.

 Based on ferromagnetic powder and carbon black, inorganic materials such as abrasives, lubricants, hardeners, and the like are dispersed in a binder solution having one or more functional groups through a high dispersion process. The magnetic coating coating solution thus prepared was applied onto a nonmagnetic support to form a magnetic layer capable of high density recording, followed by orientation, drying, surface smoothing, curing, and cutting, resulting in recording loss, property deterioration, and magnetic layer resulting from the nonmagnetic support. Make sure there is no damage.

At this time, the magnetic layer of the magnetic strip produced according to the present invention is capable of high-density magnetic recording. In addition, the binder contains one or more functional groups to provide excellent dispersibility and excellent durability. Furthermore, by controlling the glass transition temperature of the binder, it is possible to prevent recording loss and degradation, which are important characteristics of the magnetic strip, and to form a thin film having excellent durability.

As the nonmagnetic support of the present invention, known films such as polyethylene terephthalate, polyethylene naphthalate, polyaramid, polycarbonate, polyamide, polyimide, polyamideimide and aramid can be used. The non-magnetic support has a centerline average surface roughness of 0.1 m or less, preferably 0.05 m or less. In addition, such a nonmagnetic support should not only have low center line average surface roughness but also have no coarseness of 1.0 μm or more. In addition, the shape of the surface roughness can be freely controlled by a filler to be added as needed. Such pillars may be oxides such as Ca, Si, Ti, organic fine particles such as carbonates, acrylics, and the like. The ferromagnetic powder that can be used in the magnetic layer is not particularly limited. For example, γ-Fe ₂ O ₃ , Co containing γ-Fe ₂ O ₃ , Fe ₃ O ₄ , Co containing Fe ₃ O ₄ , CrO ₂ , Co-Ni-P alloy, Fe-Co-Ni alloy, barium ferrite, Known ferromagnetic powders such as strontium ferrite can be used. As the abrasive, inorganic materials such as alpha ferrite, SiO ₂ , TiO ₂ , ZrO ₂ , SnO ₂ , Sb ₂ O ₃ , Cr ₂ O _3, and Al ₂ O ₃ may be used. Kinds of carbon blacks that can be used include special blacks or rubber blacks, and specifically, there are pellets (beads) or powder type carbon blacks having a particle size of 40 nm or less. Examples of carbon blacks having a particle size of 40 nm or less include Blackbotsel, Regal 660 series, Vulcan 9A32, Vulcan P, Monarch 880, Monarch 800, Black Pulse 880, Black Pearl 800, Vulcan XC-72, Regal 330R , Regal 99R and Degussa's Princedex series, the Princedex 85, 75, L, 55, 45, 40, 35 and the Colombian's Raven 2000, Conducttex 900, Raven 1250, 1170, 1020, 850 and Mitsubishi's # 850 , MCF 88, MA600, # 3150, # 45, # 47, # 44, # 33, CF 9 etc.LG's high black series 600L, 50L, 50LB, 40B1, 40B2, 45LB, 40L, 30L, 30LB , 20L, 5L, 40, 30, 30B, 20, 20B, 10, 10B, etc., which may be used alone or in combination, and are a kind of pellet (bead) or powder type carbon black having a particle size of 40 nm or more. Kabot's Black Pearls 280, 130, Monarch 120, Degusa's Printex A, G Colombian's Raven 14, 430 Mitsubishi's # 20, # 10 Lucky Black and 150B, may be used alone or in combination, such as 160B. Examples of the lubricant include ester fatty acids and fatty acids, and specifically, lauric acid, myristic acid, stearic acid, butyl stearate, oleic acid, oleyl alcohol, lauryl alcohol and the like can be used alone or in combination. As the aluminum system, diisobutyl (oleyl) aceto acetyl aluminate, diisopropyl (oleyl) acetoacetyl aluminate, acetoalkoxy aluminum diisopropylate and the like can be used. As the binder having one or more functional groups of the present invention, a mixed system containing at least one selected from polyester-based polyurethane resins, vinyl chloride-based resins, urethane-based resins, and polyisocyanate-based resins can be used. -COOM, -OSO ₃ M, -SO ₃ M, PO (OM ₁ ) (OM ₂ ), -OPO (OM ₁ ) (OM ₂ ), NR ₄ X (where M, M ₁ , M ₂ is Li, Na , K, H, -NR ₄ or HNR ₃ , R represents an alkyl group or H, and X represents a halogen atom. Specifically, Union Carbide's UCAR-527, UCAR-569, VAGH, VYHH, VMCH, VAGF, VAGD, VROH, VYES, VYNC, VMCC, XYHL, XYSG, PKHH, PKHJ, PKHC, PKFE, etc. TA, MPR-TA5, MPR-TAL, MPR-TSN, MPR-TMF, MPR-TS, MPR-TM, MPR-TAO, etc., 100OW, DX80, DX82, DX83, 100FD from Electrochemistry, etc., MR105, MR100, Nippon-N2301, N2302, N2304 from Japan Polyurethane Co., Ltd., Pantex T-5105, T-R3080, T-5201 from Nippon Polyurethane Co., Ltd., CA-271, CA-237, CA-2237, CA- 236, CA-239, CA-397, CA-398, CA-399, 84847, CA-151HT, CA-152, etc., TI-9200, TI-1331, TI-8222, TI-8202, TI-8321, TI-8405, TI-8550, TI-8800, TI-8860, TI-8870, TI-8890, TI-8900, TI-8911, TI-8912 and Novion's 5714F1, 5703P, 5701F1P, 5788P , 5719P, 5715P, 5706P, 5755P, 5778P, 5799P and the like can be used. As a hardening | curing agent, the isocyanate type hardening | curing agent etc. containing a suitable amount of NCO group can be used. Specifically, triylene diisocyanate, 4-4 'diphenylmethane diisocyanate, hexamethylene diisocyanate, xylene diisocyanate, naphthylene-1,5- diisocyanate, triphenylmethane triisocyanate, etc. can be used. The organic solvent which can be used as a solvent is ketones, such as acetone, methyl ethyl ketone, methyl isobutyl ketone, diisobutyl ketone, and cyclohexanone, methanol, ethanol, propanol, butanol, isobutyl alcohol, and isopropyl alcohol in arbitrary ratios. Alcohols such as methylcyclohexanone, esters such as methyl acetate, butyl acetate and isobutyl acetate, glycol ethers such as glycol dimethyl ether, glycol monoethyl ether and dioxane, aromatics such as benzene, toluene and chlorobenzene Chlorinated hydrocarbons, such as hydrocarbons, methylene chloride, ethylene chloride, and carbon tetrachloride, can be used. Such an organic solvent does not necessarily need to be 100% pure and may contain impurities of 10 to 30% or less, preferably 10% or less, such as isomers, side reactions, and decomposition products, in addition to the main component. Initially disperse the inorganic materials such as the usable magnetic material, carbon black, and abrasive materials in the binder solution in an appropriate amount suitable for the purpose, and then add auxiliary materials such as the binder, lubricant, and curing agent, and then prepare or paint the coating through dispersion process again. Using the technique of to prepare a paint for the above purpose. The binder solution and the paint are coated on a non-magnetic support that runs at a high speed in a series of steps to produce a magnetic strip after drying, smoothing, curing and cutting.

Therefore, according to the present invention, not only a high quality magnetic recording medium having excellent magnetization reversal and excellent electron conversion characteristics, but also coating can be applied as a thin film, thereby improving productivity by reducing cost and manufacturing time of magnetic paint. Of course, there are cost savings.

Hereinafter, the present invention will be described in detail with reference to Examples. However, the scope of the present invention is not limited by the following examples. The average glass transition temperature and the magnetic layer glass transition temperature of the binder were adjusted to form a magnetic coating solution, and then applied on a nonmagnetic support to form a magnetic layer. The paint composition of the present invention is 30 to 50 weight of magnetic material (γ-Fe ₂ O ₃ Coercive force 350Oe), 10 to 20 weight of polyurethane-based binder (glass transition temperature -30 to 60 ℃) with respect to 100 parts by weight of mixed solvent and polyvinyl It is characterized by producing by mixing and dispersing 5 to 10 weight of the binder (glass transition temperature 60 ~ 100 ℃). Electric paint has excellent paint and magnetic properties and can improve productivity. The above invention will be described in detail based on the following examples.

[Example 1] 2 parts by weight of lubricant, 1 part by weight of abrasive (KP Chemical APL-4), antistatic agent (BPL, Cobot, USA) based on 100 parts by weight of mixed solvent (MEK / Toluene / Cyclohexanone = 4/4/2) 10 Parts by weight, binder solution 20 parts by weight, magnetic material (γ-Fe 2 O 3 coercive force 350 Oe) 30 parts by weight of the mixture after mixing for 2 hours to disperse the mixed composition using a basket mill to produce a magnetic paint. 2 parts by weight of a curing agent (Aekyung Chemical TM-50) was added to the produced magnetic paint, followed by stirring for 10 minutes, and then applied to a polyester film (after drying, having a thickness of 13 μm), oriented, dried, and then cut to obtain a magnetic strip sample. . The binder solution has one or more functional groups in 20 parts by weight of the mixed solvent and has a glass transition temperature of 45 ° C. 6 parts by weight of binder is dissolved and used.

[Example 2] In the production of the magnetic paint of Example 1, the magnetic strip sample was obtained in the same manner by mixing the raw materials for 4 hours.

Example 3 In the preparation of the magnetic coating of Example 1, a binder solution was dissolved in 20 parts by weight of a mixed solvent and 6 parts by weight of a binder having one or more functional groups and having a glass transition temperature of 65 ° C. to obtain a magnetic strip sample.

[Example 4] In the production of the magnetic paint of Example 3, the magnetic strip sample was obtained in the same manner by mixing the raw materials for 4 hours.

[Example 5] In the production of the magnetic coating of Example 1, a binder solution was dissolved in 20 parts by weight of a mixed solvent and 6 parts by weight of a binder having one or more functional groups and having a glass transition temperature of 25 ° C. to obtain a magnetic strip sample.

[Example 6] In the production of the magnetic coating of Example 5, the magnetic strip sample was obtained in the same manner by mixing the raw materials for 4 hours.

[Comparative Example 1] A magnetic stripe sample was obtained by adding and dispersing the binder solution of Example 1 by adding and dispersing the primary binder as a conventional method.

[Comparative Example 2] After the same dispersion method as in Comparative Example 1, the mixing time was only 4 hours to obtain a magnetic strip sample.

[Comparative Example 3] A magnetic stripe sample was obtained by adding and dispersing the binder solution of Example 3 after adding and dispersing the primary binder, which is a conventional method.

COMPARATIVE EXAMPLE 4 The dispersion method of Comparative Example 3 was made the same, and only 4 hours of mixing time was obtained, and a magnetic stripe sample was obtained.

[Comparative Example 5] A magnetic stripe sample was obtained by adding and dispersing the binder solution of Example 5 after adding and dispersing the primary binder, which is a conventional method.

[Comparative Example 6] The dispersion method of Comparative Example 5 was made the same, and only 4 hours of mixing time was obtained to obtain a magnetic strip sample.

The characteristics of the magnetic strip samples produced in the above Examples and Comparative Examples are shown in the table below.

division Average glass transition temperature of binder (℃) Glass transition temperature of magnetic layer (℃) Paint manufacturing time (min) Example 1 45 95 360 Example 2 45 98 420 Example 3 65 115 350 Example 4 65 114 410 Example 5 25 70 380 Example 6 25 68 430 Comparative Example 1 45 93 610 Comparative Example 2 45 94 640 Comparative Example 3 65 108 680 Comparative Example 4 65 105 650 Comparative Example 5 25 65 670 Comparative Example 6 25 66 660

                              <Table 1>

* Paint production time: It is the time produced before the magnetic layer is applied. It takes time until the gloss level of the paint reaches 85.

division Filtration rate surface Coefficient of friction durability Magnetic force Square ratio Example 1 81 Prize medium medium 312 0.812 Example 2 88 Prize Prize Prize 319 0.813 Example 3 82 Prize Prize Prize 309 0.809 Example 4 89 Prize Prize Prize 310 0.810 Example 5 80 medium medium medium 311 0.802 Example 6 83 medium medium medium 312 0.803 Comparative Example 1 75 Ha medium medium 301 0.798 Comparative Example 2 76 medium medium medium 302 0.801 Comparative Example 3 74 medium medium medium 305 0.785 Comparative Example 4 78 medium medium medium 301 0.805 Comparative Example 5 73 Ha Ha Ha 308 0.768 Comparative Example 6 78 Ha medium medium 305 0.798

                            <Table 2>

1. Filtration rate

The higher the weight ratio of paint passed through the measuring device for 70 seconds with 100g of magnetic paint in the filtration rate measuring device and the pressure of 3㎏ / ㎠,

2. Coating film surface

The state of the coating film surface after application | coating was visually discriminated and represented as top, middle, and bottom.

Phase: Excellent without surface cracks.

Medium: Fine surface cracks are visible but surface is excellent

Bottom: Many surface cracks

3. Friction coefficient of magnetic layer after hardening

The friction coefficient of the surface of the magnetic layer was measured using a friction coefficient measuring instrument, and then expressed as top, middle and bottom.

Phase: 0.2 or more and less than 0.3

Medium: 0.3 or more and less than 0.4

Lower: 0.40 or more

4. Coating film durability

After repeating the magnetic head on the surface of the magnetic layer for 1,000 times, the electron conversion signal was evaluated and expressed as upper, middle and lower.

Phase: Less than 1dB of signal degradation

Medium: Signal degradation 1dB or more but less than 2dB

Lower: signal degradation 2dB or more

As shown in the above table, it is possible to provide a magnetic strip having excellent characteristics of the magnetic layer.

5. Magnetic force and angular ratio

It is measured using the VSM (Vibration Sample Magneto Meter). As the square ratio is closer to 1, the dispersibility is evaluated as excellent.

As shown in Tables 1 and 2 above, the magnetic strip produced through the glass transition temperature change using the functional group of one or more binders in the magnetic paint manufacturing process manufactured by the present invention has improved productivity and magnetic properties as compared to the prior art. And it has the effect of producing a durable product.

Claims (2)

In a method of forming a magnetic strip (magnetic layer) comprising a magnetic material, a binder, a lubricant, and a solvent on a nonmagnetic support, a method of producing a magnetic strip, wherein the average glass transition temperature of the binder used for the magnetic paint is 45 ° C. or more and 70 ° C. or less. The magnetic strip is characterized in that the glass transition temperature of the magnetic layer after the hardening reaction after the addition of the curing agent is 80 ℃ or more The magnetic strip is characterized in that the binder used in the magnetic coating is a single dispersion after the continuous mixing and mixing at least one or more functional groups by a combination