JPS61211830A - Production of magnetic recording medium - Google Patents

Abstract

PURPOSE:To suppress the generation of lines on the surface of a magnetic coated film to improve the surface smoothness of the magnetic coated film and to improve an electromagnetic conversion characteristic by using a smoothing material having a chemically or electrolytically polished top end edge and bringing the smoothing material into contact with the surface of the magnetic coated film to smooth the surface of said film. CONSTITUTION:The smoothing material 6 is the flexible smoothing material formed by polishing chemically the top end edge 8 of a synthetic resin film 7, and dissolving away the burrs. Said material is attached to a sheet attaching seat roll 1 and is so disposed that the part 8 thereof contacts with the undried magnetic coated film 5 on a substrate film 4 traveling in an arrow A direction via a backing roll 3. The undried magnetic coated film 5 coated and formed on the film 4 is smoothed by the flexible material 6 having the edge part 8 smoothed by the chemical polishing and therefore the good smoothing is made possible and the magnetic coated film having excellent surface smoothness is formed. The magnetic recording medium having the excellent electromagnetic conversion characteristic is obtd.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a method for manufacturing a magnetic recording medium, and more specifically, to a method for manufacturing a magnetic recording medium whose magnetic coating film has good surface temperature properties and excellent electromagnetic conversion characteristics. Regarding the method.

[Conventional technology]

In general, magnetic recording media such as magnetic tapes are produced by applying a magnetic paint consisting of magnetic powder, a binder component, an organic solvent, and other necessary components onto a base film using a coating machine such as a graphia roll. While still in the undried state, as shown in FIG. The running base film 4- is brought into contact with an undried magnetic coating I1 and subjected to a smoothing treatment.
(No. 9-53631) [Problems to be Solved by the Invention] However, the smoothed synthetic resin sheet used in this conventional method is simply cut with a slitter, and the cut end of the tip edge is Because there is firmness, etc., when it comes into contact with the magnetic coating surface, dust and undispersed substances in the magnetic paint are likely to get caught in this firmness. Difficulties include dirt, undispersed matter, etc. that grow over time, and eventually streaks appear on the magnetic coating, deteriorating the surface smoothness of the magnetic coating, causing dropouts, and deteriorating electromagnetic conversion characteristics. There is.

[Means for solving problems]

This invention was made as a result of conducting various autopsies in order to eliminate such drawbacks, and the tip edge part was chemically removed. υfbaf
Or, by using electrolytic polishing smoothing treatment (A) and contacting this smoothing treatment 'rA to the surface of the magnetic coating film, the generation of streaks on the surface of the magnetic coating film can be avoided. This effectively suppresses the magnetic flux and improves the surface smoothness of the magnetic coating, thereby sufficiently improving the electromagnetic conversion characteristics.

Embodiments of the present invention will be described below with reference to FIGS. 1 to 3 showing embodiments of the invention.

In Fig. 1, 6 is a flexible smoothing material made by chemically polishing the leading edge part 8 of the synthetic resin film 7, dissolving and removing the firmness, and making it smooth. The undried magnetic coating 1 of the base film 4 is attached to the base film 4 and runs in the direction of the arrow through the backing roll 3. 5-1x so that its distal end edge portion 8 is in contact with 5-1x.

Therefore, the undried magnetic coating film 5 coated and formed on the base film 4 has a tip end portion 8 that has been chemically polished.
? n-ized flexible 'l' lft processing month f
Since the i 4 is smoothed, the 'l'/?
The tip edge part 8 of I-treated 4A6 is coated with 1/1 coat of nitrate! A
5, even if it touches 1 degree, any undivided material in the magnetic paint will be stuck to the tip edge part 8, and there will be no IJI, even if 1 shielding 11) square square 11 processing is performed, &+ 411
Good flatness with no streaks on the surface of the coating! A magnetic recording medium with excellent electromagnetic conversion characteristics can be obtained by performing the 4-containing treatment, forming a magnetic 11 coating with excellent surface sub-dipping I11.

A flexible smoothing material 6 made of such a synthetic resin film (AU, polyester, polyacetate 11, polycarbonate 1, polyester 6, polycarbonate 1:] pyrene, crosslinked polyethylene, 47 resin) Synthetic resin films such as polyester are suitable for use, and those with a thickness of 200 p or less are preferably used.In addition, as a flexible flattening film, , metal smoothing treatment material 6 is also suitably used, even 4J, aluminum, soft 81.'], hard steel,
Stainless steel, copper, 11 brass, phosphor bronze, Ninogel-iron alloy, GJ, and metal foils having a thickness of 100 μm or less made by plating these with nickel, chromium, etc. are preferably used.

Chemical polishing for smoothing the tip edges 8 of these flexible smoothing materials 6 made of synthetic resin films or metal foils is performed by cutting these flexible smoothing materials 6 into predetermined sizes with a slitter. After degreasing the material 6 using an ultrasonic cleaner or the like containing a solvent such as trichlene or acetone, a solvent capable of dissolving these, for example, in the case of a polyester film, a solvent such as parachlorophenol or concentrated sulfuric acid, In addition, in the case of metal foils such as mild steel, hard steel, stainless steel, permalloy, phosphor bronze, and aluminum foil, this is done by immersing them in an appropriate mixed solvent such as nitric acid, sulfuric acid, phosphoric acid, glacial acetic acid, etc. Chemical polishing dissolves the firmness that occurs when the slitter cuts the film to the specified size, so the edges of the tip become smooth, and the magnetic coating film is maintained in good condition without streaks on the surface of the magnetic coating film. Smoothing processing can be performed.

In addition, when the flexible smoothing material 6 is a metal foil, the smoothing treatment of the edge portion 8 of the flexible smoothing material is also performed by electrolytic polishing, and this electrolytic polishing is performed using a slitter in a predetermined manner as described above. Soft S, Oka, hard steel, stainless steel, permalloy, cut to size.
After degreasing the flexible smoothing treatment material 6 made of metal foil such as phosphor bronze or aluminum foil using an ultrasonic cleaner or the like containing a solvent such as 1-hericlene or acetone,
Clean the edges of the metal foil with perchloric acid, glacial acetic acid,
This is carried out by immersing in an electrolytic solution in which acetic anhydride, phosphoric acid, sulfuric acid, chromic anhydride, etc. are suitably dissolved, and applying jIJ current at a predetermined current density. When such electrolytic polishing is performed,
As in the case of chemical polishing described above, the firmness that occurs when the metal foil is cut into a predetermined size with a slitter is dissolved.
The tip edge portion becomes smooth, and the magnetic coating film can be smoothly smoothed without creating streaks on the magnetic coating surface.

FIG. 2 shows another example of the smoothing treatment material, and this smoothing treatment material 9 is similar to the flexible parallelization treatment 4 described above.
The difference between A6 and ζJ is that the shape is a cup cock, and the cross section is semicircular. The tip edge gt+r+ is arranged so as to come into contact with the undried magnetic coating 5 of the base film 4J- running in the direction of the arrow through the huffing roll 3.

Therefore, the base film E1. History of the undried magnetic coating 11 formed by coating 54: I, the tip edge part 11 is chemically polished, the firmness is removed by melting, and the cylindrical shape with a semicircular cross section is smoothed. Since the smoothing process is performed by the month 9, this smoothing process 4) The tip edge of J9
Even if ++]] comes into contact with the magnetic coating film 5, it will not be possible to determine which part of the magnetic coating material is being pulled into the tip edge part]1')
Even if smoothing is performed for a long time,
Magnetic) (A magnetic coating film with no streaks per coating, good smoothing treatment, and excellent surface IIA properties is formed, resulting in a magnetic recording medium with excellent electromagnetic conversion characteristics.

Figure 3 (a) and (b) show other examples of the same block 1' and J-shaped smoothing process 4 as shown in Figure 2.
1\In Shinokomono, these are shown on the first page, 1; ″)
, a smoothing process ROSI, 1, a large circle JM (root-like flat end of j) 1 process lAl2, or LJ: ili-like plate-like smoothing process 4A13, shape i; +lR
4a, 2l! IJ not determined.

These smoothing treatment materials] 2 and 13 also have their respective tip edge portions 14 and 15 shaped like q(υ[elbow and flattened), and therefore, these smoothing treatment materials 12. 13, and these were combined into a base film 7I-1.
Even when the undried magnetic coating 5 coated on -1 is subjected to smoothing treatment, the cross section shown in FIG.
1. The same effect as in the case of smoothing treatment material 0 with a circular cylindrical shape was obtained, (11 (IC%fi I) There were no streaks in the history. A magnetic I11 coating film with excellent properties is formed, resulting in a magnetic recording medium with excellent electromagnetic conversion characteristics.

Gorera's block-shaped smoothed material! 3.12 and 1
In the case of 3, as in the case of the flexible warming treatment month 6, interest rate i;t it! j is not constant, for example, those made of synthetic resins such as polyester, polyacete 1, polycarbonate 1, nylon 6, boria 1-I pyrene, crosslinked polyethylene, tetrafluoroethylene, etc.
Or aluminum, mild steel, hard steel, stainless steel 11
1N, copper, brass, phosphor bronze, nickel-iron alloy, or metals made of these materials coated with nickel, chromium, etc. are all suitable.

Further, chemical polishing for smoothing the tip edge portions 11, 14 and 15 of these smoothing materials 9, 12 and 13 is performed in the same manner as in the case of the flexible smoothing material 6, When these smoothing materials 9, 12 and 13 are made of metal, electrolytic polishing is performed in the same manner.

Examples of the magnetic powder used in this invention include γ
-Fe203 powder, Fe3O4 powder, CO-containing r-Fe
Various conventionally known magnetic powders such as 203 powder, Co-containing Fe3O4 powder, Cr02 powder 1, Fe powder, and CO powder are widely included, and binder resins include vinyl chloride-vinyl acetate copolymer, polyvinyl butyral resin, Conventional binder resins such as cellulose resins, polyurethane resins, polyester resins, and isocyanate-1-compounds are widely used.

In addition, as organic solvents, conventionally used organic solvents such as toluene, methylisophylgene, notylconitylgene, hexanone, tetrachlorofuran, and ethyl acetate may be used alone or in combination with LJ. A mixture of the above is used.

Furthermore, the coating method for coating a base film with a magnetic paint prepared by mixing and dispersing these magnetic powders, a binder resin, an organic solvent, etc. can be applied using a knife caulk, a gravure coater, a reverse one-by-one coater, Any conventionally used coater such as a P1' coater, a kiss coater, a gui coater, or a curtain coater can be suitably used.

In addition, various commonly used additives such as dispersants, wetting agents, (iJr polishing agents, anti-fluorescence agents, etc.) may be optionally added to the magnetic paint.

〔Example〕

Next, embodiments of the invention will be described.

Example 1 CO-adhered 7-Fe2O3 powder 100 parts by weight 2L Cellulose T-11GI (Asahi 10//manufactured by Kasei Co., Ltd., nitrocellulose) Nistan 5702 (Gutsudoriso 9//manufactured by Dichemical Co., Ltd., urethane elastomer) Coronate L ( Nippon Polyurethane 1 Trifunctional low molecular weight isocyane-1 compound (manufactured by 〃〃Kogyo Co., Ltd.) Granular α-FC203 powder 5 // Carbon blank 5 〃Zinc stearate
0.5 n-butyl stearate
0.5〃Methylisobutylkene 1-1001
1 toluene 100 This composition was mixed and dispersed in a ball mill for 48 hours to prepare a magnetic paint, and this magnetic paint was applied to a polyester base film with a thickness of 15 μm using a coating machine so that the dry thickness was 5.5 μm. . Next, as a smoothing treatment material, a polyester film with a thickness of 50 μm was cut into a predetermined size with a rotary blade, and after being placed in an ultrasonic cleaner containing L-Reclen, it was degreased, cleaned, and dried. Next, using a polyester film smoothing material 6 whose tip edge is chemically polished by immersing it in parachlorophenol at 30°C for 2 minutes, the smoothing material 6 is polished as shown in Figure 1. The tip edge portion 8 was brought into contact with the undried magnetic coating film 5 to perform a smoothing treatment. Thereafter, it was subjected to a magnetic field orientation treatment, then dried, and then cut to a predetermined width to produce a magnetic tape.

Example 2 In the smoothing treatment in Example 1, the smoothing treatment consisting of a chemically polished polyester film +. Instead of t 6, a 50μ thick SUS27 foil was immersed in an ultrasonic cleaner containing trichlorene to degrease it, and after drying, it was then soaked in 180cc of perchloric acid with a concentration of 70% by weight and 770ml of acetic anhydride.
The tip edge part 8 was immersed in an electrolytic solution containing cc and 50 cc of water and electrolytically polished at a current density of 2 A/d m. Smoothing treatment + A6 consisting of SUS27';Is was used. Except for this, the smoothing treatment was carried out in the same manner as in Example 1 to produce a magnetic tape.

Example 3 In the smoothing treatment according to LJ in Example 1, instead of the smoothing treatment material 6 made of chemically polished polyester film, a permalloy foil with a thickness of 50 μm was immersed in an ultrasonic cleaner containing Triclean. After degreasing and cleaning, drying,
30 cc of nitric acid and 10 cc of sulfuric acid at °C. ! : Phosphoric acid 10cc
Chemical? A magnetic tape was produced by carrying out the smoothing treatment in the same manner as in Example 1, except that the smoothing treatment material 6 made of iJF-polished permalloy foil was used.

Example 4 In the smoothing treatment in Example 1, instead of the smoothing treatment material 6 made of a chemically polished polyester film,
A phosphor bronze foil with a thickness of 25 μm was immersed in an ultrasonic cleaner containing Trichloride to degrease it, and after drying, it was then soaked in phosphoric acid 4.
．． Example 1 was carried out except that the smoothing material 6 made of phosphor bronze foil was electrolytically polished by immersing the tip end portion 8 in an aqueous solution of 0.0 g/12 m and was electrolytically polished at a current density of 5 A/d m. A magnetic tape was produced by performing smoothing treatment in the same manner.

Example 5 In the smoothing treatment in Example 1, instead of the smoothing treatment material 6 made of a chemically polished polyester film,
Aluminum foil with a thickness of 20 tt was immersed in an ultrasonic cleaner containing trichloride to degrease it, and after drying, it was then placed in an electrolytic solution in which 800 cc of phosphoric acid, 200 cc of sulfuric acid, and 50 g of chromic anhydride were dissolved and mixed. Immerse the tip edge part 8 and
A magnetic tape was produced by carrying out the smoothing treatment in the same manner as in Example 1, except that the smoothing treatment material 6 made of aluminum foil that had been electrolytically polished at a current density of OA/dm was used.

Example 6 In the smoothing treatment in Example 1, instead of the smoothing treatment material 6 made of a chemically polished polyester film,
As shown in FIG. 2, a cylindrical roll 10 made of SLJS2'7 and having a semicircular cross section is immersed in an ultrasonic cleaner containing Trichlorene to degrease it, and after drying, it is then washed with a 70% by weight superimposed water. 180 cc of chloric acid, 770 cc of acetic anhydride, and 5 ml of water
Example except that flat melding treatment +19 made of 5US27 with a semicircular cross section, which was electrolytically polished at a current density of 5A/dm by immersing the tip edge part 11 in an electrolytic solution mixed with 0cc and 0cc, was used. A magnetic tape was produced by performing smoothing treatment in the same manner as in 1.

Example 7 In the smoothing treatment in Example 1, instead of the smoothing treatment material 6 made of a chemically polished polyester film,
As shown in Fig. 2 (a), a plate-like smoothed plate +412 with a large arc made of brass is immersed in an ultrasonic cleaner containing 1 to 100% Reclean to degrease and clean it, followed by Na
OT (5g/N, Na2CO350gall, Na
3 Immersed in a solution with a composition of 420g/I-PO,
Alkaline degreasing was performed for 10 minutes while maintaining the temperature at PHII at ℃, and after washing thoroughly, the mixture was heated to 20℃ for 2 minutes in a mixed solution of 25 parts by weight of concentrated sulfuric acid, 5 parts by weight of concentrated nitric acid, and 20 parts by weight of a-hydrochloric acid. A magnetic tape was produced by performing the smoothing treatment in the same manner as in Example 1, except that the tip end portion 14 was immersed and chemically polished to use the smoothing treatment material 12 made of plate-shaped brass having a large circular arc.

Example 8 In the smoothing treatment in Example 1, instead of the smoothing treatment 4A6 made of chemically polished polyester film, 50μ thick chrome plating was applied to the mild steel base as shown in Figure 2 (b). The tongue-shaped plate 13 prepared in step 1 was immersed in an ultrasonic cleaner containing trichloride to degrease it, and after drying, it was subsequently soaked in 180 cc of perchloric acid with a concentration of 70% by weight and 77 cc of acetic anhydride.
Smoothing treatment consisting of a tongue-like plate plated with chrome on a mild steel base which was electrolytically polished at a current density of 5 A/dm by immersing the tip edge portion 15 in an electrolytic solution containing 0 cc and 50 cc of water. A magnetic tape was produced by performing the smoothing treatment in the same manner as in Example 1 except that Material 13 was used.

Comparative Example 1 In the smoothing treatment in Example 1, instead of the smoothing treatment material 6 made of a chemically polished polyester film,
A magnetic tape was produced by performing smoothing treatment in the same manner as in Example 1, except that chemical polishing was omitted and a 50 μm thick polyester film cut with a rotary blade was used as the smoothing material.

For the magnetic tapes obtained in each of the Examples and Comparative Examples, the number of streaks generated after 30 minutes of smoothing treatment and the number of streaks after 15 μsec were measured.

The table below shows the results.

Table [Effects of the Invention] As is clear from the above table, the magnetic tapes (Examples 1 to 8) obtained by the manufacturing method of the present invention have less streaks than the magnetic tape obtained in Comparative Example 1. The number of occurrences and 1'
The number of loss outs is small, and this is the reason for the invention of
It can be seen that by manufacturing method A, a magnetic recording medium with good surface flatness of the magnetic coating film and excellent electromagnetic conversion characteristics can be produced.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram showing an outline of the smoothing process of the present invention which is included in the manufacturing process of a magnetic tape, FIG. 2 is an explanatory diagram showing an outline of another example of the same flattening process, and FIG. (b) and (1)
Fig. 4 is a side view showing another example of the smoothing process used in the present invention, and Fig. 4 is a 5+i-L
It is an explanatory diagram showing an outline of the smoothing treatment in the culm (since JFL). 4. Base film, 5. Magnetic coating film, 6, 9.] 2
．． 13...ilZ smoothing shrine, 8. II, 14.15
...Advanced Edge Department patent applicant Elate Maxell Co., Ltd. procedure? ni official document (spontaneous) April 26, 1985 1, Indication of the case 1985 Patent Application No. 52731 2, Name of the invention Method for manufacturing magnetic recording media 3, Person making the amendment Relationship to the case Patent applicant Address: 1-88 Ushitora-chome, Ibaraki City, Osaka Name (
581) Hitachi Maxell Co., Ltd. Representative Atsushi Nagai 4, agent address 2-41, Bakoro-cho, Higashi-ku, Osaka City Figures 1, 2, and 3 of the map. 6. Contents of correction (1) Figures 1, 2, and 3 of the drawings will be corrected as shown in the attached sheet. Part 3 (a) 4-substrate film

Claims (1)

[Claims] 1. Apply a magnetic paint onto the base film, and then smooth the magnetic paint film formed by this application by chemically polishing or electrolytically polishing the tip edge. A method for manufacturing a magnetic recording medium, characterized by smoothing the surface of a magnetic coating film by bringing it into contact with the surface.