JP3291067B2 - Coating device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a coating apparatus, and more particularly to a coating apparatus capable of performing coating without failure even under high-speed coating conditions when manufacturing photographic films, photographic papers, magnetic recording media and the like.

[0002]

BACKGROUND OF THE INVENTION Various methods such as roll coating, gravure coating, extrusion coating and the like can be used to apply a coating solution as a liquid coating composition to a belt-like body such as a photographic film, photographic paper, a magnetic recording medium, or the like. Among them, it is the most common among them because a coating film having a uniform extrusion coating can be obtained.

In extrusion coating, for example, Japanese Patent Application Laid-Open No. 1-28-28
No. 8364 and No. 2-251265,
The shape of the edge portion is extremely important for stably performing uniform coating.

However, in such extrusion coating, the surface of the continuously running strip may come into contact with the edge of the coater die, and wear of the edge due to hard fine particles in the coating solution cannot be avoided. The coating performance is remarkably reduced, such as a streak failure caused by a slight deformation. For example, in the case of a coating solution for magnetic recording, fine and hard fine particles, for example, an abrasive such as alumina oxide and chromium oxide, or a ferromagnetic powder are often contained in the coating solution, and the productivity is improved. For this purpose, there is a demand for high-speed coating (100 m / min to 1000 m / min or more) as much as possible, and thus prevention of abrasion of the edge portion has become a more important issue. In addition, when hard particles are contained in the coating solution, the slit portion of the coater die, which is a portion through which the coating solution passes, is spread due to abrasion, and the amount of extrusion of the coating solution is changed. It has become a challenge.

Furthermore, a coater die used for extrusion coating requires uniform dimensional accuracy in the width direction in order to stably perform uniform coating in the width direction with respect to the running direction of the strip. For this reason, precision grinding or polishing is usually performed for the processing. At this time, the used grindstone or abrasive particles may enter the processing surface of the die, and the grindstone or abrasive particles that have entered the edge surface fall off due to peripheral wear, causing deformation at the edge portion, It causes a failure such as a streak, and remarkably lowers coating performance. Also,
Corrosion may occur from the portion caused by the fine particles of the grindstone or abrasive grains that have entered. Furthermore, in recent years, the demand for thinning has been particularly strong in magnetic recording media.
Due to long-term use of a coater die in the case of a thin film, there has been a problem that coating characteristics are reduced and electric characteristics are deteriorated due to coating film surface roughness caused by the coater.

Conventionally, in order to prevent abrasion of the edge portion and the slit portion, for example, as described in JP-A-57-84771, the edge portion of a coater die is formed of a cemented carbide, As described in -71869, the strength of the edge portion is increased by forming the coater die body from ceramic.

However, materials having high wear resistance, such as cemented carbides and ceramics, increase in material cost in proportion to the wear resistance and also make processing such as grinding and polishing difficult. It has the disadvantage of high cost. Furthermore, in the case of cemented carbide, among the fine particles contained in the above-mentioned coating solution, there are those having higher hardness than the cemented carbide, so that wear cannot be prevented, and in the case of ceramic, the material is brittle. Since it is easy to chip and it is difficult to process a delicate shape of an edge portion, particularly a sharp corner portion, there is a disadvantage that an edge portion having ideal coating performance cannot be obtained. Furthermore, when the shape of the edge portion is out of the required accuracy range due to abrasion, the entire coater die must be discarded and a new one needs to be made, which is extremely uneconomical and complicated. .

[0008]

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a coating apparatus in which a coater die can be formed easily and at low cost, and in which stable coating performance can be obtained.

[0009]

Means for Solving the Problems The inventors of the present invention have made intensive studies to achieve the above object, and as a result, have accomplished the present invention.

That is, the coating apparatus according to the present invention is a coating apparatus for extruding and coating a coating liquid on the surface of a continuously running strip, wherein at least the strip and / or the coating liquid of the extrusion coater die of the coating apparatus are coated with the coating liquid. The contact portion is characterized by being coated with an amorphous carbon film (DLC) having a coating strength (Beakers hardness) HV of 1700 or more after coating.

In a preferred embodiment of the coating apparatus according to the present invention, the coating is performed by an ion plating method.

[0012]

DETAILED DESCRIPTION OF THE INVENTION Hereinafter, a specific configuration of the present invention will be described with reference to the accompanying drawings. FIG. 1 is a cross-sectional view showing one embodiment of a coater die of a coating apparatus according to the present invention.
In FIG. 1, reference numeral 1 denotes a coater die. The coater dice 1 includes a front bar 11 </ b> A having a front edge surface 11, a center bar 12 </ b> A having a center edge surface 12, and a back edge surface from the upstream side in the running direction of the band 2. 13 comprising a back bar 13A having
A first slit 15 is formed between the front bar 11A and the center bar 12A so as to communicate with the first liquid reservoir 14 for the coating liquid.
3A and a second fluid reservoir 16 communicating with the second reservoir 16 of the coating fluid.
A slit 17 is formed. The cross-sectional shape of the coater die 1 shown in FIG.
As in Example 1 of FIG. 251265 (FIG. 1), it is shown as a cross section in the running direction of the band. FIG. 1 shows the case where the coating solution is applied in two layers, and FIG. 2 described later shows the case of single-layer coating. However, the present invention is not limited to these, and the present invention is not limited thereto. It is needless to say that the present invention is also applicable to the case of merging in the middle of the slit or the case of applying three or more layers.

The application of the coating solution to the strip 2 will be described.
1. In the process of going around the center edge surface 12 and the back edge surface 13, a metering pump (not shown)
The coating liquid of the first layer is extruded from the exit of the first slit 15 through the outlet 6, and the coating liquid of the second layer is extruded from the exit of the second slit 17, whereby two layers are applied to the surface of the strip 2. The details of the band 2 will be described later.

In the present invention, a portion where the abrasion occurs during coating, a portion which comes into contact with the strip 2 and / or a portion which comes into contact with the coating liquid, more specifically, the front edge surface 1
1. The center edge surface 12, the back edge surface 13, the first slit 15 and the second slit 17 are coated with an amorphous carbon film (DLC) having a coating strength (Beakers hardness) of HV1700 or more after coating. is there. The coating of the film only needs to cover at least these portions, and the coating portion may be the entire coater die 1.

Before and after coating, a front edge surface 11, a center edge surface 12, and a back edge surface 13 are provided.
Is preferably within the center line average roughness specified in JP-A-2-20785, that is, 5.0 μm or less, preferably 3.0 μm or less, more preferably 1 μm or less.

Next, the means for coating the film will be described. Examples of the coating means include various known ultra-hard coating methods, for example, a CVD (chemical vapor deposition) method, a salt bath immersion (TD process) method, a sputtering method, and a PVD (physical vapor deposition) method. An ion plating method, which is a belonging method, is preferable. The ion plating method is a method having a number of advantages, such as obtaining a good-quality, hard and dense coating at a lower processing temperature than other methods and irrespective of the type of the material to be processed. Depending on the type of evaporation, it is classified into a matrix method, an RF (high frequency excitation) method, an ARE (activated reaction vapor deposition) method, an HCD (hollow cathode discharge) method, a multi-cathode method, a cluster ion beam method, and the like. It should be noted that the actual coating is often performed by combining several of these methods.

The material of the film to be coated by the above method includes a film strength (Beakers hardness) HV 170 after coating.
Zero or more amorphous carbon films (DLC) are mentioned.

When the coating is performed by the ion plating method, the coater die 1 is divided into three bars 11A, 12A and 13A in advance by removing engaging members such as screws. Is preferable because the coating of each slit can be performed uniformly without unevenness.

Here, Vickers hardness refers to JIS Z
2244-1981. As the test method, JIS Z2251-1980 and J
The one specified in ISB7734-1977 is used, and for example, Shimadzu Dynamic Ultra Micro Hardness Tester DUH-200 manufactured by Shimadzu Corporation can be used. Obtaining a film hardness (Vickers hardness) of HV 1700 or more can be achieved by appropriately examining the film thickness and the like according to what is used as the material of the film.

As described above, the present invention provides a coater die 1
Of the abrasion point of the coating film strength after coating (Beakers hardness) HV
By coating with an amorphous carbon film (DLC) of 1700 or more, abrasion of the edge portion 11 due to contact with the strip 2 or edge portion 1 due to fine particles mixed in the coating liquid or the like.
2, 13 and / or the wear of the slits 15 and 17 can be prevented, and furthermore, by coating the surface,
Since the grindstone and abrasive grains that have entered during processing from the edge surface do not fall off and do not come in contact with paint,
Corrosion does not occur from that part, and uniform application of the coating solution can be stably performed. Moreover, since the coated film is responsible for the prevention of abrasion, the coater die 1 main body has S
US steel, die steel, for example, SUS420J2, SUS
630, SUS440C, SUS304, SKD11,
An easily and inexpensive material such as SKD61 can be used. Of these materials, the stainless steel used in conventional coater dies is easier and cheaper to process and has higher corrosion resistance, and there is no need to change the processing conditions when manufacturing conventional coater dies, making it easier and lower cost. Can be formed into a desired shape.

Even when the film is worn, the initial performance is restored by recoating, so that it is not necessary to recreate the entire coater die, which is extremely low cost and simple. Further, the present invention can also be applied to a conventional coater dice not taking this measure.
The shape of the edge portion is the same as described in
The shapes described in JP-A-364 and JP-A-2-251265 are preferred. The strip 2 referred to in the present invention generally means a polyethylene terephthalate, polyethylene-2,6-naphthalate, cellulose die having a width of 0.3 to 3 m, a length of 45 to 20000 m, and a thickness of 2 to 200 μm. Plastic film such as acetate, cellulose triacetate, cellulose acetate propionate, polyvinyl chloride, polyvinylidene chloride, polycarbonate, polyimide, polyamide, etc. Film: paper: polyethylene on paper,
Flexible band consisting of paper coated or laminated with α-polyolefins having 2 to 10 carbon atoms such as polypropylene and ethylene butene copolymer: metal foil such as aluminum, steel, tin, etc., or the band. And a belt-like material having a preliminary processed layer formed on the surface of the substrate. Further, the belt-like body 2 is coated with a coating solution according to its use, for example, a photographic photosensitive coating solution, a magnetic coating solution, a coating solution for surface protection, antistatic or lubricity, etc. It is applied in a film thickness of 20 μm or less, preferably 10 μm or less, particularly preferably 4 μm or less, dried, and then cut into a desired ring and length. Typical products include various photographic films and photographic papers. , Magnetic tape, and the like.

In the present invention, in particular, as in the case of a magnetic coating solution, alumina oxide, chromium oxide, α-alumina, fused alumina,
Stable coating is possible even with an abrasive such as α-iron oxide, silicon oxide, silicon nitride, tungsten carbide, molybdenum carbide, boron carbide, corundum, boron nitride, or a liquid containing magnetic powder.

[0023]

Embodiments of the present invention will be described below. The components, ratios, operation orders, and the like shown below can be variously changed without departing from the spirit of the present invention. In the following examples, "parts" are all parts by weight.

Example 1 A coater die 1 having a cross section shown in FIG. 1 and a width of 720 mm was made from the materials shown in Table 1, and the surface of the coater die 1 was coated under the same conditions as shown in Table 1. At this time, the front edge surface 11, the center edge surface 12, and the back edge surface 13 are described in JP-A-2-207865.
It was within the center line average roughness specified in the item. When coating the film, the front edge surface 11, the center edge surface 1
2, the front film 11A, the center bar 12A, and the back bar 13A, including the back edge surface 13, the first slit 15, and the second slit surface 17, are coated with the respective films shown in Table 1 by ion plating. Coating was carried out at the thickness indicated in 1. At the time of coating, after the engaging members such as screws are removed and disassembled for each bar 11A, 12A, 13A, coating is performed except for the bottom surface of each bar 11A, 12A, 13A.
After the coating was completed, it was assembled. At this time, coater dice 1
A test piece of 30 × 30 × 5 mm having the same material as the main body and having substantially the same surface roughness as each of the edge surfaces 11, 12 and 13 was prepared, and the film was simultaneously coated under the conditions shown in Table 1. The material of the coater die 1 shown in Table 1 is S for stainless steel.
US630, a cemented carbide used WC-based cemented carbide, and a ceramic used ZrO ₂ -based.

The front edge surface 11, the center edge surface 12, and the back edge surface 13 after coating are the same as before coating.
It was within the center line average roughness specified in JP-A-2-207865.

The hardness of the coated film was measured with a Shimadzu Dynamic Ultra-Micro Hardness Tester DUH-200 manufactured by Shimadzu Corporation. Since the coater main body cannot be placed on the sample stage of the ultra-micro hardness tester due to its size and weight, the hardness of the coating on the test piece was measured.
Subsequently, the following upper layer magnetic composition was kneaded and dispersed to prepare an upper layer magnetic paint. (Upper magnetic composition) Fe-Al-based ferromagnetic metal powder 100 parts (average major axis length: 220 nm, X Sentsubu径(average crystallite size): 20nm) (Hc: 1600Oe , σ s: 120emu / g) Potassium sulfonate-containing vinyl chloride resin 10 parts (Zeon Corporation MR-110) Sodium sulfonate-containing polyurethane 5 parts (Toyobo UR-8700) Alumina (average particle size: 0.6 μm) 5 parts Carbon black (average particles) Diameter: 30mμ) 1 part Myristic acid 1 part Stearic acid 1 part Butyl stearate 1 part Cyclohexanone 100 parts Methyl ethyl ketone 100 parts Toluene 100 parts

(Lower Layer Magnetic Composition) In place of the ferromagnetic metal powder, a Co-γ-Fe ₂ O ₃ powder (Hc: 8
The lower magnetic coating composition having the same composition as the upper magnetic composition described above was kneaded and dispersed except that 00O _e , the average major axis length was 300 nm).

Next, the magnetic paint for the lower layer and the magnetic paint for the upper layer obtained above were added with 3 parts of polyisocyanate (Coronate L manufactured by Nippon Polyurethane Co., Ltd.).
Using a coater dice 1 under each condition shown in FIG.
m on a belt-shaped body 2 which is a polyethylene terephthalate film at a coating speed CS of 300 m / min.
Next, while the coating film was not dried, a magnetic field orientation treatment was performed at 3000 Gauss to form a magnetic layer including a lower layer having a thickness of 2.7 μm and an upper layer having a thickness of 0.3 μm after drying. Table 1 shows the results of the coating properties of the obtained magnetic layers. The evaluation was performed with a coating time of 50 hours, 1
The test was performed at three time points after 50 hours and 300 hours. As a result, the number of coating streaks per coating width was counted.

[0029]

[Table 1]

From the results shown in Table 1, the amorphous carbon film (DL) having a coating strength (Beakers hardness) of HV 1700 or more after coating is obtained.
It can be seen that when coated with C), stable coating performance is obtained.

Example 2 The materials shown in Table 2 were used to form the cross section shown in FIG.
A coater die having a width of 720 mm was prepared, and a film was coated on the surface of the coater die under the respective conditions shown in Table 2. At this time, the film was coated in the same manner as in Example 1, and after the film was coated, the front bar 11A and the back bar 13A were assembled. The material of the coater die shown in Table 2 is the same as the coater die of Example 1, SUS630 for stainless steel, WC for cemented carbide, and Zr for ceramic.
An O ₂ system was used. Subsequently, the same paint as the upper layer paint of Example 1 was prepared, and 3 parts of polyisocyanate (Coronate L manufactured by Nippon Polyurethane) was added. Is applied at a coating width of 700 mm and a coating speed of CS 300 m / min on the belt-shaped body 2 which is a polyethylene terephthalate film of
Next, while the coating film was not dried, a magnetic field orientation treatment was performed at 3000 Gauss to form a magnetic layer having a thickness of 2.0 μm after drying. Table 2 shows the results of the coating properties of the obtained magnetic layers. Other evaluation conditions are the same as those in the first embodiment. The cross-sectional shape of the coater die 1 shown in FIG. 2 is the same as that of the embodiment of Japanese Patent Application Laid-Open No. 1-288364 by the present applicant, and is a single-layer coating compared to the two-layer coating of FIG.

[0032]

[Table 2]

From the results in Table 2, it can be seen that stable coating performance can be obtained when coated with an amorphous carbon film (DLC) having a coating strength (Beakers hardness) of HV1700 or more, as in Example 1. I understand.

Example 3 Application was performed using the same magnetic paint and coater die as in Example 1 except that the coating was performed under the following conditions and a back coat layer was provided. A coating width of 700 mm and a coating speed of CS 300 m on a polyethylene terephthalate film having a thickness of 7 μm
/ Min continuously, then perform magnetic field orientation treatment while the coating film is not dried, then perform drying and then perform surface treatment with a winding calendar to obtain an upper layer thickness of 0.3 μm.
m, a lower magnetic layer having a thickness of 2.7 μm was formed. further,
A coating having the following composition is applied to the surface (back surface) of the polyethylene terephthalate film opposite to the magnetic layer, and the coating is dried and calendered to form a 0.8 μm thick back coat layer. Was formed to obtain a wide raw magnetic tape.

Carbon black (Laben 1035) 40 parts Barium sulfate (average particle diameter 300 nm) 10 parts Nitrocellulose 25 parts Polyurethane resin (N-2301 manufactured by Nippon Polyurethane) 25 parts Polyisocyanate compound (Coronate L manufactured by Nippon Polyurethane) 10 parts Cyclohexanone 400 parts Methyl ethyl ketone 250 parts Toluene 250 parts

Of the wide-width original magnetic tape thus obtained, the original magnetic tape at a coating length of 4000 m and 1 million m was slit to produce an 8 mm-wide video magnetic recording medium. The following evaluation was performed on this magnetic recording medium.

: CN ratio of electric characteristics (dB): 7 MHz by 8 mm video camera CCDV-900 manufactured by Sony Corporation.
Is 7MH when a single sine wave of 7MHz is input.
The difference (dB) between the reproduced output between z and 6 MHz is calculated as 9M
The difference between the reproduction output at 9 MHz and the reproduction output at 8 MHz when a single sine wave of 9 MHz was input was measured for the CN ratio of Hz. The results are shown in Table 3.

[0038]

[Table 3]

From the results shown in Table 3, the amorphous carbon film (DL) having a coating strength (Beakers hardness) HV of 1700 or more after coating is obtained.
It can be seen that when coated with C), a stable coating performance of the coating film quality without deterioration of the electrical properties in long-term use can be obtained. As a result, the high-speed coating property was significantly improved, and the amorphous carbon film (DLC) provided stable coating performance in which the electrical characteristics did not deteriorate even at high speed.

[0040]

According to the present invention, an amorphous carbon film (DLC) having a coating strength (Beakers hardness) of HV1700 or more after coating is applied to a portion of the extruder coater die of the coating apparatus which comes into contact with the strip and / or the coating solution. ), It is possible to provide a coating apparatus in which a coater die can be easily formed at a low cost and stable coating performance can be obtained.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing one embodiment of a coater die of a coating apparatus according to the present invention.

FIG. 2 is a cross-sectional view showing another embodiment of the coater die of the coating apparatus according to the present invention.

DESCRIPTION OF SYMBOLS 1 Coater die 2 Strip 11 Front edge surface 11A Front bar 12 Center edge surface 12A Center bar 13 Back edge surface 13A Back bar 14 First liquid reservoir 15 First slit 16 Second liquid reservoir 17 First 2 slits

──────────────────────────────────────────────────続 き Continuation of front page (56) References JP-A-62-95170 (JP, A) JP-A-2-71869 (JP, A) JP-A-57-84771 (JP, A) 13254 (JP, U) JP-A 62-43652 (JP, U) JP-A 2-142667 (JP, U) JP-A 3-86079 (JP, U) (58) Fields surveyed (Int. Cl. ⁷ , DB name) B05C 5/02 B05B 1/04 G11B 5 / 842,5 / 848 G03C 1/74

Claims (2)

(57) [Claims] In a coating apparatus for extruding and coating a coating solution on the surface of a continuously running strip, at least a portion of the extrusion coater die of the coating apparatus which comes into contact with the strip and / or the coating liquid is coated with a coating solution. Film strength (Beakers hardness)
A coating apparatus characterized by being coated with an amorphous carbon film having an HV of 1700 or more. 2. The coating apparatus according to claim 1, wherein said coating is formed by an ion plating method.