JP2006205018A - Coating apparatus and precoated metallic sheet - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a roll coater system coating apparatus by which paint containing a coarse granular substance whose size is larger than the thickness of a coating film to be formed on the sheet to be coated can be applied onto the sheet to be coated without changing the ratio of the coarse granular substance and consequently the earth performance (electric conductivity provability) of a precoated sheet cannot be deteriorated. <P>SOLUTION: The coating apparatus is used for transferring the paint containing a metallic particle such as a nickel particle to the sheet, which is to be coated and is conveyed to one direction, from an applicator roll to form the coating film and provided with two rolls to be rotated naturally without causing interference with each other and a paint supply unit for feeding the paint to the space between two rolls from above to quantify the amount of the paint to be supplied. The surface of one of two rolls has 45-55 hardness and 1-5 μm roughness (Ra). The other of two rolls is made from a metal and the surface thereof has <1 μm roughness (Ra). The obtained coating film has 1-3 μm average thickness, contains the metallic particle having the major axis exceeding twice of the coating film thickness and has ≥95% electric conductivity provability. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a coating apparatus, and more particularly to a coating apparatus capable of uniformly and thinly applying a paint containing coarse metal particles having a diameter larger than that of a coating film.

  For example, housings of electronic devices such as PCs, drive cases such as CD-ROMs built into PCs, exterior members of measuring devices, etc. have functions as a ground for removing static electricity generated during operation. Things are used. In addition, because the measuring instrument members such as the housing and drive case are required to be lightweight and formable, an aluminum plate coated (painted) with paint is often used. Therefore, in order to exhibit the earth function, an aluminum plate coated with a coating material in which metal particles are added and mixed in the resin is employed. When the metal particles are added, not only can the ground be taken at a plurality of parts of the component, but also the probability that the surface in contact with the member exhibits electrical conductivity is improved, and the reliability of the ground function is ensured. Here, it has been proposed to use spherical, scale-like, chain-like, or spike-like nickel particles as the metal particles.

The size of the metal particles in the paint varies depending on the purpose. For example, when conductivity is imparted, nickel particles having a particle size distribution range of 1 to 11 μm and an average particle size of 3 to 7 μm are connected to the nickel particles. Various particles such as the chain nickel particles or the flat nickel particles having a thickness of several microns and a major axis of 1 to 110 μm can be selected.
In addition, the metal particles are usually contained in a total of about 25 to 55 wt% in the coating film, and particularly when the metal particles are nickel particles, in order to prevent sedimentation separation due to the difference in specific gravity, It is supposed to be used with constant stirring and mixing.

By the way, brush coating, spray coating, and the like are known as methods for applying a coating containing metal particles to a plate to be coated. From the viewpoint of coating performance such as film thickness and uniformity and production efficiency, A roll coater system that spreads paint on a rotating roll, transfers the paint squeezed by the roll to another roll, repeats transfer from roll to roll as necessary, and finally transfers it from the applicator roll to the plate to be coated. A coating method using a coating apparatus is known.
For example, FIG. 3 is a schematic diagram illustrating a typical apparatus of the roll coater type coating apparatus. In the roll coater type coating apparatus 30 shown in the figure, 1 is a paint pan, 2 is a paint, 4 is a pickup. Rolls 5 and 5 are applicator rolls, 7 is a backup roll, and 8 is a plate to be coated. A part of the pick-up roll 4 is immersed in the paint 2 in the paint pan 1 and is set so that the other end is pressed by the applicator roll 5 with a required pressure.

That is, when the paint 2 is applied to the plate 8, the pickup roll 4 immersed in the paint 2 in the paint pan 1 is rotated in the direction of the arrow 33 and the applicator roll 5 is naturally rotated in the direction of the arrow 35. . On the other hand, the plate to be coated 8 moves in the direction of the arrow 39 while being supported by the backup roll 7 rotating in the reverse direction of the arrow 37 with respect to the applicator roll 5.
When the rolls are rotated as described above and the plate 8 is moved, the paint 2 adhered to the surface of the pickup roll 4 is squeezed when passing through the gap between the pickup roll 4 and the applicator roll 5. Part of the paint that has been dropped (reference numeral 40) and passed through is transferred to the applicator roll 5. The paint 2 on the transferred applicator roll 5 surface is further transferred onto the plate 8 to be coated.
If such a roll coater type coating apparatus is used, a necessary amount of paint is transferred and applied, so that it can be applied continuously and a uniform coating film can be obtained.

As a roll coater type coating apparatus for forming a coating film containing metal particles, for example, an apparatus for applying a paint containing a bright pigment is known (for example, see Patent Document 1).
When a paint containing a glitter pigment is applied, the glitter pigment blended in the paint or ink is deformed or miniaturized over time, and the glitter performance when applied is lowered. As a means for preventing this decrease in glitter, a sculpture roll in which linear concave grooves are engraved on a pick-up roll that holds the paint is used, and the amount of paint containing the glitter pigment supplied to the sculpture roll surface is determined by the doctor. A roll coating technique that adjusts in combination with a blade has been proposed.
JP 2002-192061 A

In the method described in Patent Document 1, a paint containing a bright pigment is supplied to an engraving roll surface in which linear grooves are engraved from an ink chamber, and from the engraving roll surface to which the paint is supplied by a doctor blade. Since this is a technique of scraping off a part of the paint and then transferring and painting it onto the plate cylinder, the size of the paint is increased by the doctor blade in the case of a paint having a large glitter pigment size or as the paint film thickness becomes thinner. Larger pigments will be removed. In order to prevent this, engraving roll concave grooves are enlarged, which causes the occurrence of spots on the coating surface, and forming a smooth thin film coating surface that contains coarse metal particles and has no mottled pattern. It ’s difficult.
On the other hand, in order to impart conductivity, it is desired to reduce the thickness of the coating resin portion. In order to reduce the thickness of the resin portion, for example, when the coating apparatus described in FIG. 3 is used, the pressure between the pickup roll 4 and the applicator roll 5 is increased to narrow the gap, and the amount of paint If the gap between the rolls is narrowed in this way, coarse metal particles larger than the roll gap cannot pass through the roll gap, and the original coarse metal particle content ratio cannot be maintained. Becomes non-uniform and the earth performance (conductivity probability) decreases.
Accordingly, an object of the present invention is to make a coating containing coarse metal particles having a large diameter compared to the thickness of the coating applied to the plate to be coated, thin and uniform without changing the content ratio of the coarse metal particles. It is providing the coating apparatus which can be apply | coated to a to-be-coated board. Another object of the present invention is to provide a coated metal plate provided with a conductive coating film that does not degrade the earth performance.

In order to solve the above-described problems, one of the coating apparatuses of the present invention includes at least one pair of rolls that rotate naturally with each other and a quantitative supply device that top-feeds the paint between the pair of rolls. A coating apparatus for forming a coating film by transferring a necessary amount of coating material between one roll and transferring a necessary amount of coating material to one roll and then transferring the coating material contained in the one roll to a plate to be coated. One of the pair of rolls has a roll surface hardness of 45 to 55 degrees and a roughness of Ra of 1 to 5 μm, and the other roll is made of metal and has a surface roughness of Ra of less than 1 μm. A painting device was used.
Further, another coating apparatus of the present invention includes at least one pair of rolls that rotate naturally with each other and a metering supply device that top-feeds the paint between the pair of rolls, and the paint is applied between the pair of rolls. After top feeding and transferring the required amount of paint to one roll, the paint contained in the one roll is transferred to the third roll, and the paint is transferred from the third roll to the plate to be coated. A coating apparatus for forming a coating film, wherein one of the pair of rolls has a roll surface hardness of 45 to 55 degrees, a roughness Ra of 1 to 5 μm, and the other roll The coating apparatus is made of metal and has a surface roughness Ra of less than 1 μm.
In the coating apparatus of the present invention, the roll having a surface hardness of 45 to 55 degrees and a roughness of Ra of 1 to 5 μm is preferably a rubber roll such as urethane rubber, butyl rubber, EPDM rubber or the like.

The painted plate of the present invention is a metal plate coated with a paint containing metal particles using any of the coating apparatuses described above, and has an average coating thickness of 1 to 3 μm and the metal A coated metal plate having a particle diameter exceeding 2 times the average thickness of the coating film was used.
In the coated plate of the present invention, the conductivity probability of the metal particles is preferably 95% or more.
Moreover, nickel particles can be used as the metal particles.
Furthermore, a pure aluminum plate or an aluminum alloy plate can be used as the metal plate.

  The present invention can be applied to a coating containing coarse metal particles without generating a spotted pattern even when the coating thickness is thin, and the grounding performance of the coated plate is good, so it is suitable for a housing of an electronic device or the like. It has an effect that can be used.

The paint of the present invention contains coarse metal particles having a diameter larger than the coating film thickness in the resin, and other particles containing particles having a small diameter, flat particles, a solvent, a lubricant, a wax, graphite or the like. .
As metal particles for imparting electrical conductivity, nickel particles are preferably used. As nickel particles, in addition to spherical particles having a particle size distribution range of 1 to 11 μm and an average particle size of 3 to 7 μm, chain nickel particles connected with the nickel particles, or flat having a thickness of several microns and a major axis of 1 to 110 μm Various particles such as nickel particles can be selected.
In addition, the metal particles are preferably contained in a total amount of about 25 to 55 wt% in the coating film after drying.
Although the thickness of the coating film is not limited, the thinner is practically more advantageous in terms of cost, so the average thickness is 1 to 3 μm when dried. Therefore, if the average thickness of the coating film is 1 to 3 μm, the diameter of coarse particles is larger than the thickness. The ratio of the coarse particles to the paint is preferably 25 wt% or more with respect to the dry coating film in order to exhibit the additive properties of the particles.
The coated plate to which the paint is applied is not limited as long as it is a metal plate, but an aluminum plate is preferable from the viewpoint of lightness and formability. Here, the aluminum plate includes a pure aluminum plate and an aluminum alloy plate.

  The coating apparatus of the present invention is a roll coater type coating apparatus, a metal having a diameter larger than the thickness of the coating film formed by transfer onto the plate to be coated, preferably a diameter more than twice the thickness of the dried coating film. A coating apparatus that forms a coating film by transferring a coating material containing particles from an applicator roll to a plate to be coated flowing in one direction.

The coating apparatus of the present invention will be specifically described with reference to the drawings.
(First embodiment)
FIG. 1 is a schematic view for explaining a coating apparatus 10 according to the first embodiment of the present invention. In FIG. 1, 1 is a paint pan, 2 is a paint and contains coarse metal particles, 3 is a metering supply device for supplying the paint 2 from above, and 5 is a soft roll roughened by an applicator roll. Reference numeral 6 denotes an adjustment roll for adjusting the amount of paint supplied. 7 is a backup roll, 8 is a plate to be coated, and 18 is a coated metal plate after the coating film 17 is formed. The applicator roll 5 and the adjustment roll 6 are in a natural rotating relationship with each other, and the feeding amount of the coating material 2 that is top-fed from the metering supply device 3 between the applicator roll 5 and the adjustment roll 6 is determined by the pair of rolls. The amount of paint transferred to the applicator roll 5 is adjusted and quantified by adjusting the pressing force by means not shown. A known means can be used to adjust the pressing force.
In the coating apparatus 10 shown in FIG. 1, since the coating is applied to the plate to be coated only with the two rolls 5 and 6 that are in a natural rotating relationship with each other, one applicator roll 5 uses a soft roll whose surface is roughened. Is preferred. The soft roll having a roughened surface used as the applicator roll 5 preferably has a roll surface hardness of 45 to 55 degrees and a roughness of 1 to 5 [mu] m in average surface roughness Ra. In addition, the formation method of the roughened soft roll should just grind the rubber-made roll surface using the rotating grindstone whose roughness is 1-5 micrometers in Ra. The polishing technique may be a normal technique.
The other adjustment roll 6 is a roll for adjusting the amount of paint supplied, and is made of metal. The surface roughness Ra is less than 1 μm. If the surface of the adjusting roll 6 is plated with chromium or the like, a hard surface can be obtained.
Here, the hardness of the roll surface is in accordance with the definition and display of arithmetic average (Ra) shown in JIS K6301 and the roughness (average surface roughness) Ra in JIS B0601-1994. The cut-off value was also according to JIS.

  The pair of applicator roll 5 and adjustment roll 6 rotate naturally, and when the coating 2 is narrowed by the gap between the adjustment roll 6 and the applicator roll 5, the rough surface of the applicator roll 5 in which coarse metal particles in the coating are soft. When approaching the recess, it is pushed into the recess on the surface of the other metal adjustment roll 6, but when the rotation proceeds and the gap becomes wider, the coarse metal particles are pushed out again by the reaction force of the soft applicator roll 5, and enter the gap between the rolls. Since it is fed to the rear of the roll without being caught, even if there are coarse metal particles in the paint, the content ratio of the metal particles in the paint does not change, and a spot pattern does not occur.

In this way, if one of the pair of adjusting roll 6 and applicator roll 5 is a soft roll having a roughened surface and the other is made of a metal having a smooth surface, coarse metal particles are formed in the paint during the coating process. Even if it is contained, the content ratio of the metal particles in the paint does not change. In this case, the effect of the present invention is exhibited even when the adjustment roll is a soft roll having a roughened surface and the applicator roll is made of a metal having a smooth surface. That is, when transferring the paint, the content ratio of the metal particles in the paint does not change as long as the combination of the roughened soft surface and the smooth hard surface is maintained.
However, in order to apply the coating so that the applicator roll 5 does not scratch the hard plate, it is more preferable to use a soft roll having a roughened surface.

  If a soft roll with one surface roughened and the other roll surface has a low hardness, the pressing force on the metal particles is low, and the soft roll with coarse metal particles roughened. It is difficult to be applied to the concave portion, and the content ratio of the particles in the paint cannot be stably maintained. Accordingly, one of the rolls is preferably made of metal. Also, if the surface roughness Ra of the metal roll is not smoothed to be less than 1 μm, the amount of coating feed tends to be uneven due to the overlapping of the concave and convex portions on the roll surface, and the coating thickness is particularly thin, for example with an average thickness In the case of 1 to 3 μm, it becomes uneven and a smooth coating film cannot be obtained.

Further, if the surface hardness of the roughened soft roll is less than 45 degrees, the reaction force of the soft roll is small, and it is difficult to extrude the coarse metal particles from the recess after the roll rotation, and the distribution of the coarse metal particles in the coating film is uniform. Therefore, the conductivity is slightly lowered, the deformation is large with respect to the pressing force of the metal roll, and the gap between the pair of rolls is not stable, so that the paint feed rate cannot be made steady. Further, uneven polishing during roll polishing is likely to occur, and the coating surface tends to become uneven. Further, when the hardness of the roughened soft roll exceeds 55 degrees, the hardness between the rolls is high, and the roughening effect of the roughened soft roll is not exhibited, and the feed rate of the coarse metal particles in the paint is steady. Can not be converted.
Further, when the surface roughness of the roughened soft roll is less than 1 μm in Ra, the ratio of the metal particles applied to the recesses is low, and the roughening effect of the roughened soft roll cannot be exhibited and the coarseness in the paint The feed rate of the metal particles cannot be made steady. When the surface roughness of the roughened soft roll exceeds 5 μm in Ra, the feed amount of the metal particles tends to be uneven, especially when the coating thickness is thin, for example, when the average thickness is 1 to 3 μm Thus, a smooth coating film cannot be obtained.

The roughened soft roll and the metal roll cannot squeeze the paint and cannot be supplied quantitatively unless they are naturally rotated with respect to each other. In FIG. 1, a pair of rolls that are in a natural rotating relationship with each other rotate in the directions of arrows 13 and 14, respectively. Then, the coating material transferred and fed to the roughened soft roll is transferred onto the coated plate 8 supported by the backup roll 7 rotating in the direction of the arrow 15 and fed to the coating containing coarse metal particles. A film 17 is formed to form a painted metal plate 18.
In the figure, reference numeral 9 denotes a circulation pump, and the paint 2 supplied between the rolls 5 and 6 is squeezed by the adjusting roll 6, and the surplus paint 2 is not shown, but overflows from the ends of the rolls 5 and 6. Then, it is collected in the paint pan 1 and returned to the quantitative supply device 3 again. The fixed amount supply device 3 is composed of, for example, a surge tank in which an orifice having a cross-sectional area suitable for dripping a necessary amount of paint at the tip is formed. By top-feeding the coating material from above the roll, it is possible to prevent sedimentation of coarse particles. In the coating apparatus of the present invention, a thin coating film having a high conductivity probability is formed by using the fixed quantity supply device 3 and a pair of rolls, which are soft rolls whose one of the rolls is roughened. I can do it.

(Second Embodiment)
In the present invention, another roll may be provided between a pair of rolls on which the paint is top-fed and the board to be coated, and the transfer of the paint may be repeated, and finally transferred onto the above-mentioned board to be coated. . When transfer is repeated, there is an advantage that a thinner and smoother coating film can be obtained.
FIG. 2 is a schematic view showing a coating apparatus 20 according to the second embodiment of the present invention. In FIG. 2, the same part number is assigned to the same operation as that in FIG. 1.
In FIG. 2, 5 is an applicator roll for applying paint to a plate to be coated, and 6 is an adjustment roll for adjusting the amount of paint supplied. The present embodiment is characterized in that a mediating roll 11 is provided between the applicator roll 5 and the adjusting roll 6. The paint 2 to be applied to the plate 8 is top-fed between a pair of rolls, that is, an adjustment roll 6 and an intermediate roll 11. The top-feed paint 2 is supplied to the mediating roll 11 only by a predetermined amount controlled by the adjusting roll 6. The coating material supplied to the mediating roll 11 is further transferred to the applicator roll 5 only by a predetermined amount, and further transferred from the applicator roll 5 to the coated plate 8 supported by the backup roll 7, so that finally the coated plate The desired coating film 17 is formed on the surface 8.

In FIG. 2, for example, when the mediating roll 11 is formed of a soft roll having a roughened surface, the adjustment roll 6 is formed of a metal roll having a smooth surface. Moreover, when the mediating roll 11 is formed of a metal roll having a smooth surface, the adjustment roll 6 is formed of a soft roll having a roughened surface. In these cases, as in the case of the first embodiment, the soft roll having a roughened surface has a roll surface hardness of 45 to 55 degrees and a roughness of 1 to 5 μm in average surface roughness Ra. Is preferred. The metal roll preferably has a surface roughness Ra of less than 1 μm.
In addition, the roughening method of the roughened soft roll should just grind the rubber-made roll surface using the rotating grindstone whose roughness is 1-5 micrometers in Ra. The polishing technique may be a normal technique.

  In FIG. 2, the adjusting roll 6 and the mediating roll 11 are naturally rotated in the directions of arrows 23 and 25, respectively. Further, the mediating roll 11 and the applicator roll 5 are naturally rotated in the directions of arrows 25 and 27, respectively, and a predetermined interval is maintained. The mediating roll 11 has a function of transferring the paint to the applicator roll 5. By transferring the paint using the mediating roll 11, it becomes possible to form a thinner coating film on the surface of the plate to be coated. Then, the paint 2 transferred from the mediating roll 11 to the applicator roll 5 is transferred to the coated plate 8 fed by the backup roll 7 that rotates reversely in the direction of the arrow 29, and the coating film 17 containing the coarse metal particles uniformly. The formed coated metal plate 18 is formed.

The coating material 2 containing coarse metal particles top-fed between the mediating roll 11 and the adjusting roll 6 from the coating material quantitative supply device 3 is similar to that described with reference to FIG. It is narrowed in between, adjusted to a predetermined amount and transferred to the mediating roll 11. At this time, as described above, when the coarse metal particles in the coating material reach the rough surface concave portion of the soft roll whose surface is roughened, the other metal adjustment roll 6 pushes the coarse metal particles into the rough surface concave portion, but the rotation is not performed. When the advance gap becomes wider, the particles are pushed out by the reaction force of the one roughened soft roll, and sent out to the rear of the roll without being caught by the roll, so that the content ratio of the particles in the coating can be stably maintained. . Moreover, it does not become a spotted pattern.
As described above, the coating material containing coarse metal particles which are top-feeded and constricted between the mediating roll 11 and the adjusting roll 6 and transferred by a predetermined amount naturally rotates with the mediating roll 11 and presses the mediating roll 11 with a predetermined pressure. It is transferred to the applicator roll 5 under pressure. The coating material containing the coarse metal particles transferred to the applicator roll 5 is transferred to the coated plate 8 fed by the backup roll 7, and the coated metal plate 18 on which the coating film 17 containing the coarse metal particles uniformly is formed. Become.

  The present invention is not limited to the apparatus schematically disclosed in FIGS. 1 and 2, and a predetermined amount of paint containing coarse metal particles is constricted between a roughened soft roll and a metal adjustment roll. After the transfer, it is possible to repeat the transfer by providing a roll until the coating material reaches the applicator roll. If the transfer is repeated, the coating surface becomes smooth.

Using the roll coater type coating apparatus shown in FIG.
The adjustment roll 6 had a diameter of 300 mm, the applicator roll 5 had a diameter of 300 mm, and a rubber roughening roll was used. The peripheral speed of the roll was 10 m / min for the adjusting roll 6 and 30 m / min for the applicator roll 5.
The metal plate used was a JIS5052 aluminum alloy plate with a thickness of 0.8 mm, and an H34 heat treatment material was used. The surface of the aluminum alloy plate was degreased and washed with an alkaline solution and subjected to a chromate treatment so that the surface treatment was performed so that chromium was 20 mg / m ² .
The resin used as a paint was a polyester-based resin, and auxiliary agents such as a solvent, wax, particle settling aid, defoaming aid, viscosity modifier, etc. were added as appropriate, and the viscosity was adjusted to 30 seconds with Ford Cup # 4. The following particles were used. The amount of addition was 10 wt% for each dry paint, for a total of 30 wt%.
The metal particles used are (a) spherical nickel particles: particles that are almost true spheres and independent of each other. Particle size range 1 to 11 μm, average particle size 3 to 7 μm, (b) Chain nickel particles (chain): A particle group in which particles are chained. Particle size range 1-50 μm, average particle size 6-20 μm, (c) scale-like nickel particles (scales): refers to flat particles. Three types having a major axis particle size range of 1-110 μm and an average particle size of 10-30 μm were used.

  The roll interval was adjusted so that the coating film had a dry basis and an average thickness of 2 μm. The applicator roll 5 of the coating apparatus shown in FIG. 1 is a roughened soft roll having a surface roughened to various Ra values shown in Table 1. The adjustment roll 6 was made of steel and chrome plated. Table 1 shows combinations of the roughened soft applicator roll 5 and the adjusting roll 6. Evaluation of the obtained coating film was dried after coating, the conductivity probability was measured, and the coating film surface pattern and film thickness accuracy were observed. These results are shown in Table 1.

<Measurement method of conductivity probability>
With respect to the obtained paint-coated aluminum alloy plate, the electric resistance value was measured by pressing 100 random points on the coating surface with a steel probe (diameter: 10 mm) load of 100 g by a four-terminal method, and it was 10Ω or less. The number of locations is shown in%. A large number of locations indicates a high probability of energization and easy grounding.

<Observation of coating surface pattern>
By visual observation, `` No '' when the coating surface has no spotted pattern and the metal particles are distributed uniformly, `` No '' when the coating surface is spotted and the metal particles are distributed unevenly `` Yes ”.
<Measurement of average coating thickness>
Subtract the weight of the plate from which the paint film has been removed from the 10 cm square weight of the coated board (dry paint film) and divide the resulting dry paint weight by the area to further dry the dry paint weight per unit area. It is shown as a value divided by the specific gravity of the coating film. The coating film was made to have an average thickness of 2 μm on a dry basis.

<Measurement of film thickness accuracy>
The cross section of the coating was observed with a microscope to observe the distribution of metal particles. The case where the metal particles were uniformly distributed was judged as “good”, while the case where the metal particles overlapped or was not found over a wide area was judged as “bad”.

From the results in Table 1, the hardness and roughness of the roughened soft roll, and the roughness of the metal adjusting roll are within the scope of the present invention. Since it is supplied without being reduced, it can be seen that the conductivity probability is high, the occurrence of a surface spot pattern is not generated, and the film thickness accuracy is good.
On the other hand, in Comparative Example 1 in which the hardness of the roughened soft roll is low, the feeding amount of the paint is not steady, the conductivity probability is low, a spot pattern is generated on the coating film surface, and the film thickness accuracy is also deteriorated. I understand.
Further, it can be seen that Comparative Example 2 in which the roughness of the adjusting roll is high has a mottled coating amount, a low conductivity probability, a spot pattern on the surface, and poor film thickness accuracy.
Moreover, it turns out that the comparative example 3 with the high roughness of the soft roll which roughened has a spot pattern on the surface, and its film thickness accuracy is also poor.
Further, it can be seen that Comparative Example 4 in which the hardness of the roughened soft roll is high cannot stabilize the feeding amount of the coarse metal particles, has a lower conductivity probability, and deteriorates the film thickness accuracy.
Moreover, it turns out that the comparative example 5 with the low roughness of the roughened soft roll reduces supply of a coarse metal particle between rolls, and its electroconductivity probability is low.

  Since the coating apparatus of the present invention can supply and coat without reducing coarse metal particles between rolls, the conductivity probability is high, there is no occurrence of a surface spot pattern, and a coating plate with good film thickness accuracy is obtained, In particular, it has the effect that it can be used for a casing, a drive case, a component of a measuring instrument, etc. that require grounding.

It is a schematic diagram explaining the coating apparatus of this invention. It is a schematic diagram explaining the other coating apparatus of this invention. It is a schematic diagram explaining an example of the conventional coating apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Paint pan 2 Paint 3 Quantity supply device 4 Pickup roll 5 Applicator roll 6 Adjustment roll 7 Backup roll 8 Plate to be coated 9 Circulating pump 10, 20 Roll coater type coating device 18 Paint metal plate 30 Roll coater type coating device

Claims (4)

  And at least one pair of rolls that rotate naturally with each other and a metering supply device that top-feeds the paint between the pair of rolls, and a necessary amount of paint is applied to one roll by top-feeding the paint between the pair of rolls. Is transferred to the plate to be coated to form a coating film, and one of the pair of rolls is formed on the surface of the roll. A coating apparatus characterized in that the hardness is 45 to 55 degrees, the roughness Ra is 1 to 5 [mu] m, the other roll is made of metal and the surface roughness Ra is less than 1 [mu] m.   And at least one pair of rolls that rotate naturally with each other and a metering supply device that top-feeds the paint between the pair of rolls, and a necessary amount of paint is applied to one roll by top-feeding the paint between the pair of rolls. Is transferred to the third roll, the coating device to transfer the paint from the third roll to the plate to be coated to form a coating film, One of the pair of rolls has a roll surface hardness of 45 to 55 degrees and a roughness Ra of 1 to 5 μm, and the other roll is made of metal and has a surface roughness Ra of 1 μm. Coating equipment characterized by being less than.   A metal plate to which a paint containing metal particles is applied using the coating apparatus according to claim 1, wherein the average thickness of the coating film is 1 to 3 μm and the major axis of the metal particle is a coating film. A coated metal sheet characterized by having a particle size exceeding twice the average thickness of the coating. 4. The coated metal plate according to claim 3, wherein the conductivity probability of the metal particles is 95% or more.

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