JPH0615214A - Coating device - Google Patents

Abstract

PURPOSE:To allow a running strip to be coated easily using a coater die and, at the same time, ensure that a coating capability is stable by coating an area with which the strip and a coating liquid come in contact, using a film of specified hardness, in a coating device which coats the strip by extruding the coating liquid to its surface. CONSTITUTION:A coater die 1 which applies a coating liquid to the surface of a continuously running strip 2 in an extrusion manner is equipped with a front bar 11A, a center bar 12A and a back bar 13A respectively having edge surfaces 11 to 13, arranged from the upstream side of a running direction of the strip 2. In addition, the first and the second slit 15, 17 which communicate respectively with the first and the second coating liquid reservoir 14, 16 are formed between the bars 11A, 12A and 12A, 13A, respectively. In this case, the areas where friction occurs during coating, that is, each edge surface 11 to 13 and each slit 15, 17, are coated with a film having a coat hardness after film application (Vicker's hardness) of HV>=1700. This film is either of TiN, TiC or amorphous carbon fiber, and is molded using an ion plating technique.

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 coating a photographic film, a photographic paper, a magnetic recording medium, etc. without trouble even under a high-speed coating condition.

[0002]

BACKGROUND OF THE INVENTION Various methods such as roll coating, gravure coating, and extrusion coating are used to apply a coating solution which is a liquid coating composition to strips such as photographic film, printing paper and magnetic recording materials. Among them, it is the most general among them because a uniform coating film can be obtained by extrusion coating.

In extrusion coating, for example, JP-A-1-28 is known.
As described in No. 8364 and No. 2-251265,
The shape of the edge portion is extremely important for stable uniform coating.

However, in such extrusion coating, the surface of the continuously running strip may come into contact with the edge portion of the coater die, and the wear of the edge portion due to the hard fine particles in the coating liquid is unavoidable. The coating performance remarkably deteriorates, such as streak failure due to slight deformation. For example, in the case of a coating liquid for magnetic recording, it is often the case that the coating liquid contains fine and hard fine particles, for example, an abrasive such as alumina oxide or chromium oxide, or a ferromagnetic powder. For this reason, 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 wear of the edge portion has become a more important issue. Further, when the coating liquid contains hard fine particles, the slit portion of the coater die, which is the liquid passage portion of the coating liquid, spreads due to abrasion, and the extrusion amount of the coating liquid changes, so the abrasion of the slit portion is also prevented. It has become a challenge.

Further, the 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 finish is usually performed for processing. At this time, the fine particles of the grindstone or abrasive grains used may enter the processed surface of the die, and the fine particles of the grindstone or abrasive grains that have entered the edge surface fall off due to wear of the surroundings, causing deformation in the edge portion, It causes streaks and other troubles and significantly reduces the coating performance. Also,
Corrosion may occur from that part due to the fine particles of the grindstone or abrasive grains that have entered. Furthermore, in the medium for magnetic recording, which has been especially strongly demanded in recent years,
When the coater die is used for a long time even when it is thinned, deterioration of electrical properties due to coating unevenness, coating film surface roughness caused by the coater, etc. has become a problem.

Conventionally, in order to prevent the wear of the edge portion and the slit portion, for example, the edge portion of the coater die is formed of cemented carbide as described in JP-A-57-84771, or JP-A-2. As described in JP-A-71869, the strength of the edge portion is increased by forming the coater die main body from ceramic.

However, materials having high wear resistance, such as cemented carbide and ceramics, increase in material cost in proportion to wear resistance and also make machining such as grinding and polishing difficult, so coater die molding is extremely difficult. It has the disadvantage of high cost. Further, in the case of cemented carbide, some of the fine particles contained in the above-mentioned coating liquid have a hardness higher than that of cemented carbide, so wear cannot be prevented, and in the case of ceramics, because of brittle materials, Since it is easily chipped and it is difficult to process the delicate shape of the edge part, especially the sharp corner part, there is a drawback that an edge part having ideal coating performance cannot be obtained. Furthermore, when the shape of the edge portion is out of the required accuracy range due to wear, the entire coater die must be discarded and recreated, which is extremely uneconomical and complicated. .

[0008]

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a coating apparatus which can easily form a coater die at low cost and can obtain stable coating performance.

[0009]

The present inventor has achieved the present invention as a result of extensive studies in order to achieve the above object.

That is, the coating apparatus according to the present invention is a coating apparatus for extruding and coating the coating liquid on the surface of a continuously running strip-shaped body, and at least the strip-shaped body and / or the coating solution of the extrusion coater die of the coating apparatus. The contact point is characterized by being coated with a film having a coating hardness (Beakers hardness) HV1700 or higher after coating.

In a preferred embodiment of the coating apparatus according to the present invention, the coating is performed by an ion plating method,
The film is TiN, TiC, amorphous carbon film (DLC)
It is any of the above.

[0012]

DETAILED DESCRIPTION OF THE INVENTION A specific structure of the present invention will be described below with reference to the accompanying drawings. FIG. 1 is a cross-sectional view showing an embodiment of a coater die of a coating apparatus according to the present invention.
In FIG. 1, 1 is a coater die, and the coater die 1 includes a front bar 11A having a front edge surface 11, a center bar 12A having a center edge surface 12 and a back edge surface from the upstream side in the traveling direction of the belt-shaped body 2. It is composed of a back bar 13A having 13
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 of the coating liquid, and the center bar 12A and the back bar 1 are formed.
The second that communicates with the second liquid reservoir 16 of the coating liquid between the second
The slit 17 is formed. The cross-sectional shape of the coater die 1 shown in FIG.
Similar to Example 1 (FIG. 1) of No. 251265, it is shown as a cross section in the traveling direction of the belt-shaped body. In addition, FIG. 1 shows a case where the coating liquid is applied in two layers, and FIG. 2 described later shows a case where a single layer is applied. However, the present invention is not limited to these, and is disclosed in JP-A-2-268862. Needless to say, it can be applied to the case where the slits are joined in the middle of the slit or the case of coating three or more layers.

The application of the coating liquid to the strip 2 will be described. The strip 2 is sequentially arranged in the direction of the arrow X in the order of the front edge surface 1.
1. In the process of going around the center edge surface 12 and the back edge surface 13, from the metering pump (not shown) to the liquid reservoir 14.1
The first layer coating solution is extruded from the outlet of the first slit 15 and the coating solution of the second layer is extruded from the outlet of the second slit 17 via 6, so that two layers are coated on the surface of the strip 2. The details of the strip 2 will be described later.

In the present invention, a portion that is worn during coating, that is, a portion that comes into contact with the belt-shaped body 2 and / or a portion that comes into contact with the coating liquid, specifically, the front edge surface 1 described above.
1, the center edge surface 12, the back edge surface 13, the first slits 15, and the second slits 17 are covered with a film having a coating hardness (Beakers hardness) HV1700 or higher after coating. The coating of the film has only to cover at least these portions, and the coating portion may be the entire coater die 1.

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

Next, the means for coating the film will be described. Examples of the coating means include various well-known ultra-hard coating methods such as a CVD (chemical vapor deposition) method, a salt bath dipping (TD process) method, a sputtering method, and a PVD (physical vapor deposition) method. Among them, the PVD method is used. The ion plating method, which is the method to which the method belongs, is preferable. The ion plating method is a method that has many advantages such as that a high-quality, hard and dense coating can be obtained at a lower processing temperature than any other method and that the type of material to be processed does not matter. Depending on the evaporation method, it is classified into a Matox method, an RF (radio frequency excitation) method, an ARE (activation reactive vapor deposition) method, an HCD (hollow cathode discharge) method, a multi-cathode method, a cluster ion beam method, and the like. In actual coating, several of these methods are often combined.

The material of the film coated by the above method is a coating hardness (beakers hardness) HV17 after coating.
00 or more, for example, TiC, WC, SiC, Ti
_{N, HfN, Si 3 N 4} , TiB 2, Al 2 O 3, Zr
Examples thereof include B ₂ , HfC, HfB ₂ , B ₄ C, CBN, and an amorphous carbon film (DLC). Among them, TiN, TiC, and an amorphous carbon film (DLC) are preferable, and an amorphous carbon film ( DLC) is particularly preferred.

When the film is coated by the ion plating method, the coater die 1 should be divided into three bars 11A, 12A and 13A in advance by removing the engaging members such as screws. However, it is preferable because the coating of each slit can be performed uniformly.

Here, the Vickers hardness means JIS Z
2244-1981. As a test method, particularly JIS Z2251-1980 and J
What is prescribed in ISB7734-1977 is used, and for example, Shimadzu Corporation ultrafine hardness meter 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 depending on what is used as the film material.

As described above, the present invention is a coater die 1
Hardness (Beakers hardness) after coating the wear points of
By coating with a film of HV 1700 or more, wear of the edge portion 11 due to contact with the strip 2 and wear of the edge portions 12, 13 and / or the slits 15 and 17 due to fine particles mixed in the coating liquid are prevented. Further, by coating the surface, without the abrasive stone and abrasive grains that entered during processing from the edge surface fall off,
Further, since it does not come into contact with the paint, corrosion does not occur from that portion, and uniform application of the coating liquid can be stably performed. Moreover, since the coated film takes charge of the wear prevention, the body part of the coater die 1 is made of SUS steel or die steel, for example, SUS420J2, SUS630, SUS.
Materials that are easy and inexpensive to process, such as 440C, SUS304, SKD11, and SKD61, can be used. Of these materials, the stainless steel used for conventional coater dies is easier and cheaper to process, has high corrosion resistance, and since it is not necessary to change the processing conditions when manufacturing conventional coater dies, it is easy and low cost. Can be formed into a desired shape.

Further, even if the film is worn, the initial performance is restored by re-coating, so that it is not necessary to remake the entire coater die, which is extremely low cost and simple. Further, the present invention can be applied to a conventional coater die that does not take this measure.
The shape of the edge portion is the same as that of the above-mentioned JP-A-1-288.
The shape described in No. 364 and No. 2-251265 is preferable, and the strip 2 referred to in the present invention generally has a width of 0.3 to 3 m, a length of 45 to 20000 m, and a thickness of 2 to 2. 200 μm polyethylene terephthalate, polyethylene-2,6-naphthalate, cellulose diacetate, cellulose triacetate, cellulose acetate propionate, polyvinyl chloride, polyvinylidene chloride, polycarbonate, polyimide, polyamide, etc. plastic film film: paper: polyethylene on paper ,
Flexible strip-shaped article made of paper coated with 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: or the like A band-shaped article having a substrate as a base material and a preliminary processed layer formed on the surface thereof is included. Further, the strip 2 has a coating solution suitable for its application, for example, a photographic photosensitive coating solution, a magnetic coating solution, a surface protection, an antistatic or a lubrication coating solution, on the surface of which the film thickness after drying is It is applied in a film thickness of 20 μm or less, preferably 10 μm or less, and particularly preferably 4 μm or less, dried, and then cut into desired rings and lengths. Typical products are various photographic films and photographic papers. , Magnetic tape, and the like.

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

[0023]

EXAMPLES Examples of the present invention will be described below. The components, ratios, operation sequences and the like shown below can be variously modified without departing from the spirit of the present invention. In the following examples, all "parts" are 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 respective conditions shown in Table 1. At this time, the front edge surface 11, the center edge surface 12, and the back edge surface 13 are each formed on the surface of the front edge surface 11, the back edge surface 13
It was within the center line average roughness specified in No. When coating the film, the front edge surface 11 and the center edge surface 1
2, including the back edge surface 13, the first slit 15, the second slit surface 17, the front bar 11A, the center bar 12A, the back bar 13A entire surface, each film shown in Table 1 by the ion plating method, It was coated with the thickness shown in FIG. At the time of coating, after removing the engaging members such as screws and disassembling each bar 11A, 12A, 13A, covering is performed except 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 made of 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 at the same time, the film was coated under each condition shown in Table 1. The material of the coater die 1 shown in Table 1 is S for stainless steel.
US630, WC type cemented carbide was used for the cemented carbide, and ZrO ₂ type was used for the ceramic.

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-2-20786.

The hardness of the coated film was measured by a Shimadzu dynamic ultra-fine hardness meter DUH-200 manufactured by Shimadzu Corporation. Since the coater body cannot be placed on the sample stand of the ultra-micro hardness meter due to its size and weight, the hardness of the coating film on the test piece was measured.
Subsequently, the following upper layer magnetic composition was kneaded and dispersed to prepare an upper layer magnetic coating material. (Magnetic composition for upper layer) Fe-Al based ferromagnetic metal powder 100 parts (average major axis length: 220 nm, X-ray grain size (average crystallite size): 20 nm) (Hc: 1600 Oe, σ _s : 120 emu / g) Vinyl chloride resin containing potassium sulfonate 10 parts (MR-110 manufactured by Zeon Corporation) Polyurethane containing sodium sulfonate 5 parts (UR-8700 manufactured by Toyobo Co., Ltd.) Alumina (average particle size: 0.6 μm) 5 parts Carbon black (average particles Diameter: 30 mμ) 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

(Magnetic composition for lower layer) Further, instead of the above-mentioned ferromagnetic metal powder, Co-γ-Fe ₂ O ₃ powder (Hc: 8).
00O _e, except using an average long axis length 300 nm), and the lower layer magnetic paint having the same composition as the upper layer magnetic composition was kneaded and dispersed to adjust.

Next, 3 parts of polyisocyanate (Coronate L manufactured by Nippon Polyurethane Co., Ltd.) was added to each of the magnetic coating material for the lower layer and the magnetic coating material for the upper layer obtained above, and then Table 1
Using a coater die 1 under each condition shown in
m is a polyethylene terephthalate film, and is continuously applied at a coating speed of CS 300 m / min on the strip-shaped body 2.
Next, while the coating film was still undried, a magnetic field orientation treatment was performed with 3000 Gauss to form a magnetic layer having a thickness of 2.7 μm after drying and a lower layer of thickness 0.3 μm. The results of coating properties of the obtained magnetic layer are shown in Table 1. The evaluation is that the coating time from the start of coating is 50 hours, 1
It was carried out at three time points after 50 hours and 300 hours. As a result, the number of coating stripes per coating width was counted.

[0029]

[Table 1]

From the results shown in Table 1, it can be seen that stable coating performance can be obtained when coated with a film having a coating hardness (Beakers hardness) of HV 1700 or more.

Example 2 With the materials shown in Table 2, the cross section was formed into the shape shown in FIG.
A coater die having a width of 720 mm was prepared, and the surface of the coater die was coated with a film under the same conditions shown in Table 2. At this time, as for the method of coating the film, as in Example 1, after coating the film, the front bar 11A and the back bar 13A were assembled. The material of the coater die shown in Table 2 is SUS630 for stainless steel, WC series for cemented carbide, and Zr for ceramic, as in the coater die of Example 1.
O ₂ system was used. Subsequently, the same coating material as that for the upper layer of Example 1 was prepared, 3 parts of polyisocyanate (Coronate L manufactured by Nippon Polyurethane Co., Ltd.) was added, and the thickness was 10.0 μm using a coater die under each condition shown in Table 2. On a strip 2 which is a polyethylene terephthalate film of, with a coating width of 700 mm and a coating speed of CS 300 m / min,
Next, while the coating film was not dried, magnetic field orientation treatment was performed with 3000 Gauss to form a magnetic layer having a thickness after drying of 2.0 μm. The results of the coatability of the obtained magnetic layer are shown in Table 2. Other evaluation conditions and the like 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 example of Japanese Patent Application Laid-Open No. 1-288364 by the present applicant, and the single layer coating is used instead of the double layer coating of FIG.

[0032]

[Table 2]

From the results shown in Table 2, it can be seen that stable coating performance can be obtained when coating with a film having a coating hardness (Beakers hardness) of HV 1700 or higher, as in Example 1.

Example 3 Coating was performed using the same magnetic coating material and coater die as in Example 1 except that the coating was carried out under the following conditions and a back coat layer was provided. Coating width 700 mm, coating speed CS 300 m on a 7 μm thick polyethylene terephthalate film
/ Min continuously, magnetic field orientation treatment while the coating film is not dried yet, followed by drying and surface treatment with a winding calendar, upper layer thickness 0.3μ
m, and a lower layer having a thickness of 2.7 μm was formed. further,
A backcoat layer having a thickness of 0.8 μm is obtained by applying a coating composition having the following composition to the surface (back surface) of the polyethylene terephthalate film opposite to the magnetic layer, drying the coating film, and calendering. Then, a wide original magnetic tape was obtained.

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

Among the thus obtained wide original magnetic tapes, the original magnetic tapes at the coating lengths of 4000 m and 1 million m were slit to prepare an 8 mm wide magnetic recording medium for video. The following evaluations were performed on this magnetic recording medium.

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

[0038]

[Table 3]

From the results shown in Table 3, it can be seen that when coating with a film having a coating hardness (Beakers hardness) of HV 1700 or more, stable coating performance of coating quality can be obtained without deterioration of electrical characteristics in long-term use. As a result, the high-speed coating property was significantly improved, and the amorphous carbon film (DLC) showed stable coating performance in which the electric characteristics were not deteriorated even at high speeds.

[0040]

According to the present invention, the coating film hardness (beakers hardness) HV1700 after coating the strip-shaped body of the extrusion coater die of the coating device and / or the portion contacting the coating liquid.
Since the coater die is coated with the above film, a coater die can be easily formed at low cost, and a coating device that can obtain stable coating performance can be provided.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing an 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.

[Explanation of symbols]

 1 Coater Die 2 Band 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 Second Slit

Claims (3)

[Claims] 1. In a coating apparatus for extruding and coating a coating solution on the surface of a continuously running belt-shaped body, at least a portion of the extrusion coater die of the coating apparatus which comes into contact with the belt-shaped body and / or the coating solution is after coating. A coating device characterized by being coated with a film having a coating hardness (Beakers hardness) of HV 1700 or more. 2. The coating apparatus according to claim 1, wherein the coating is performed by an ion plating method. 3. The coating apparatus according to claim 1, wherein the film is any one of TiN, TiC, and an amorphous carbon film.