JP3308614B2 - Metal strip coating equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a squeeze roll coater for coating a metal strip with a material such as a paint, and more particularly to a material having poor paintability such as a high-viscosity solid-liquid mixture or a high-concentration paint. The present invention relates to a squeeze roll coater suitable for applying to a squeeze roll.

[0002]

2. Description of the Related Art Various roll coaters are widely used as an apparatus for continuously coating a metal strip with paint. In particular, a pair of squeeze rolls (squeezing rolls) are arranged with the metal strip interposed therebetween, and the coating liquid supplied to the front and back surfaces of the metal strip by a spray nozzle or a roll or the like is placed between the squeezing rolls installed downstream and excess coating is performed. Luz click Ease roll coater to remove the liquid, especially magnesium oxide (MgO, magnesia) high viscosity solid-liquid mixture and a high concentration of the coating material such as a resin, in a suitable coating means for coating the coating having poor material such as a pigment is there.

An example of a squeeze roll coater disclosed in Japanese Patent Application Laid-Open No. 61-74683 will be described with reference to FIG. 1
Is a metal strip, 31 is a spray nozzle, 32 is a coating liquid storage tank, 41 and 42 are coating liquids, 51 is an upper squeeze roll, 52 is a lower squeeze roll, and 8 is a heat treatment furnace. The upper and lower squeeze rolls 51 and 52 are cylindrical steel rolls on the surface of which an elastic body such as rubber or resin is lined, and fine grooves are formed on the lining surface.

In this configuration, the metal strip 1 which has proceeded almost horizontally from the left as shown by the arrow is sprayed with a coating liquid 41 from a spray nozzle 31 on the front surface, and a lower part is placed in a coating liquid storage tank 32 on the back surface. In a state where the coating liquid 42 transferred from the immersed lower squeeze roll 52 is applied to each of the metal strips, the metal strip from which a pair of the upper squeeze roll 51 and the lower squeeze roll 52 mesh with each other to remove the excess coating liquid. Step 1 enters the heat treatment furnace 8 and undergoes processing such as drying and baking. Here, the heat treatment furnace 8 cannot be supported by a roll or the like because the coating liquid has not been dried yet on the entrance side. Therefore, the pass route after the squeeze roll is pulled vertically upward or in the horizontal direction as in this example. In general, a catenary furnace that follows a natural suspension curve is used as a path route in the furnace when entering the furnace.

As described above, in a squeeze roll coater, an excessive amount of a coating solution is first applied to the surface, and excess coating solution is removed by a squeeze roll. 150-165 m /
If the squeeze roll is too high, a phenomenon called cavitation or air entrainment occurs on the exit side of the squeeze roll, and there is a problem that streaks are formed on the coating film. Further, there is also a problem that if a coating material having poor coatability such as a high-viscosity solid-liquid mixture is applied to the surface of the metal strip at a high speed, the thickness of the coating film becomes non-uniform.

[0006]

[0008] The present invention is to solve these problems, and an object thereof is to provide a <br/> Kotin GuSo location of the coating with poor paint can painted at a high speed.

[0007]

[0008]

According to the present invention, there is provided an apparatus for coating a metal strip, comprising: a pair of squeeze rolls sandwiching a running metal strip, and a coating liquid supplied to both front and back surfaces of the metal strip at the entrance side of the squeeze roll. And a pair of squeeze rolls for removing excess coating liquid downstream of the squeeze roll, and the groove pitch of the roll surface of the upstream squeeze roll is adjusted to the roll surface of the downstream squeeze roll. The groove pitch is larger than the groove pitch.

[0009] Then, a smaller diameter than the upstream of the squeeze rolls squeeze rolls of the lower stream, and downstream of Squee
Zuroru downstream of providing a backup roll, respectively
To the roll arrangement and 4-high, the fact that the coating liquid supplying means is the liquid pool by the pressing bar, the upstream squeeze rolls vertically movably installed in the vertical direction while sandwiching the metal strip, together like Implementation is more desirable and desirable.

[0010]

According to the present invention, the squeeze rolls are installed in two stages in the traveling direction of the metal strip, and the coating solution supplied to the front and back surfaces of the metal strip at the upstream side of the squeeze roll is applied to the metal strip by the upstream squeeze roll. Spread evenly on both sides, squeeze lightly so that about 150% of the final coating amount remains, and then squeeze excess paint down to the desired film thickness on the downstream squeeze roll to remove it. To prepare. In order to share the functions in this manner, the grooves on the surface of the squeeze roll have a larger pitch on the upstream side to weaken the drawing action, and have a smaller pitch on the downstream side to obtain an accurate finished coating film thickness.

Further, when the amount of the coating liquid existing in the meshing portion between the upper and lower rolls is small, a streak pattern due to air entrainment at a high speed is likely to occur as described above. It is explained that when the coating liquid is separated by the upper and lower rolls at the roll exit, the inside becomes negative pressure and cavitation generates pores, which are stretched.The Mills & South formula ( the value of μv / σ) · (R / g) 3/4 is said to 10.3 generates a super El. Here, μ is the viscosity of the coating solution, v is the line speed, σ is the surface tension, R is the radius of the roll, and g is the distance between the rolls. I understand. Therefore, in a downstream squeeze roll having a small roll interval, it is advantageous to reduce the roll radius. Therefore, it is preferable to provide a backup roll to form a quadruple type.

Further, in the case of a high-viscosity solid-liquid mixture or the like in which the coating liquid tends to solidify, the nozzle of the spray nozzle is likely to be clogged. Therefore, as a means for supplying the coating liquid, the liquid is stored in a recess between the roll and the holding bar. It is preferable that the liquid is transferred to the roll surface. In addition, the upstream squeeze roll has a structure that can be moved up and down while sandwiching the metal strip, and if the path route is moved up and down at this position, the metal strip entering the downstream squeeze roll will have an entry angle of ± α with respect to the horizontal plane. Can be given. Thereby, the winding angle of the strip front and back surfaces with respect to the downstream squeeze roll can be changed, and the film thickness ratio of the strip front and back surfaces can be arbitrarily changed.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described with reference to FIGS. 1 is a metal strip, 21 and 22 are holding bars, 41 is a front surface coating solution, 42 is a back surface coating solution, 51 and 52 are upstream squeeze rolls, 51 is an upper squeeze roll, and 52 is a lower squeeze roll. Reference numerals 61, 62, 71 and 72 denote downstream squeeze rolls, 61 denotes an upper squeeze roll, 62 denotes a lower squeeze roll, 71 denotes an upper backup roll, and 72 denotes a lower backup roll.

FIG. 1 shows a roll arrangement, in which a squeeze roll 51, 52 on the upstream side has a roll body length of 1600 mm, a diameter of 180 mm, a synthetic rubber lining on the roll surface and a groove. It has been processed. under
The flow squeeze rolls 61 and 62 have a diameter of 90 mm and are smaller in diameter than the upstream squeeze roll, and the surface is also lined with synthetic rubber and grooved. These grooves are
The upstream squeeze rolls 51 and 52 have a pitch of 1.2 mm and a peak height of 0.9 mm, and the downstream squeeze rolls 61 and 62 have a pitch of 0.46 to 0.54 mm and a peak height of 0.3 to 0.8 mm. The upstream one is the downstream one
A large groove pitch than that of. Backup roll 71, 72
Is a 265mm diameter steel roll with a chrome-plated surface.

If there is no problem even if the diameter of the downstream squeeze roll is reduced to some extent due to the narrow width of the metal strip or the like, it goes without saying that the backup roll need not be provided. FIG. 2 is a cross-sectional view schematically showing the application state of the coating liquid. The coating liquid is supplied to the front and back surfaces of the strip at the entrance of the squeeze rolls 51 and 52 on the upstream side. The coating liquid is supplied to the recess between the non-rotating steel holding bars 21 and 22 installed close to the upper and lower squeeze rolls 51 and 52 to form a liquid pool, and the liquid is supplied from the roll surface to the back of the strip. Is done. When the application liquid is a high-viscosity slurry or a high-concentration paint, etc., it is easy to cause nozzle clogging in the spray method. Therefore, such a liquid pool method is preferable. However, depending on the type of the application liquid, the spray method or the method shown in FIG. A method of dipping the lower part of the roll in the storage tank or the like may be adopted.

[0016] The upstream squeeze rolls 51 and 52 coating without the coating solution evenly on both surfaces of the metal strip spread, for example, is throttled to an extent to leave about 150% of the final coating weight metal strip downstream of the squeeze rolls 61, The flow then goes to 62, where it is squeezed to the final coating amount and sent to post-processing such as drying and baking. Fig. 3 shows upstream squeeze rolls 51 and 52
Indicates that the device is installed so as to be able to move slightly up and down with respect to the horizontal pass line by a lifting means such as a hydraulic jack (not shown). For example, if the squeeze rolls are raised while sandwiching the metal strips as indicated by arrows, the squeeze rolls 61 and 62 enter the downstream squeeze rolls at an approach angle α, so that the winding angles for the downstream squeeze rolls 61 and 62 and As a result, the thickness of the coating film on the front and back surfaces is different. Therefore, the approach angle α
The thickness difference between the front and back surfaces can be controlled by changing the thickness.

[0017]

According to the present invention, it is a coating means suitable especially for coating a coating material having poor coatability, such as a high-viscosity solid-liquid mixture, and has a uniform and good coating film without nozzle clogging and uneven coating. Is formed, which is an excellent effect.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a roll arrangement according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view illustrating a state of a coating film according to an example of the present invention.

FIG. 3 is a cross-sectional view illustrating a roll arrangement according to the embodiment of the present invention.

FIG. 4 is a cross-sectional view showing a conventional technique.

[Explanation of symbols]

 1 Metal strip 21, 22 Holding bar 31 Spray nozzle 32 Coating liquid storage tank 41, 42 Coating liquid 51, 61 Upper squeeze roll 71 Upper backup roll 52, 62 Lower squeeze roll 72 Lower backup roll 8 Heat treatment furnace

──────────────────────────────────────────────────続 き Continuation of front page (56) References JP-A-60-139356 (JP, A) JP-A-58-107167 (JP, U) JP-B-55-5390 (JP, B1) JP-B-49- 1145 (JP, B1) Jikken 55-41317 (JP, Y1) (58) Field surveyed (Int. Cl. ⁷ , DB name) B05C 1/08 B05C 11/02

Claims (4)

(57) [Claims] 1. A device for sandwiching a running metal strip (1).
A pair of squeeze rolls (51, 52) and the metal strip (1) at the entrance side of the squeeze rolls (51, 52).
A coating liquid supply means for supplying a coating liquid to both front and back surfaces of the squeeze rolls (51, 52), and a pair of squeeze rolls (61, 62) for removing excess coating liquid are provided downstream of the squeeze rolls (51, 52). Upstream squeeze roll (51, 52)
The groove pitch on the roll surface of the squeeze roll (6
A metal strip coating apparatus characterized in that the groove pitch is larger than the groove pitch of the roll surface of (1), (62). 2. The downstream squeeze rolls (61, 62) are smaller in diameter than the upstream squeeze rolls (51, 52), and the downstream squeeze rolls (61, 62) are provided with backup rolls (71, 72), respectively. The coating apparatus for a metal strip according to claim 1 , wherein the downstream roll arrangement is a quadruple type. 3. The method according to claim 1, wherein the application liquid supply means includes a holding bar (21,
The coating device for a metal strip according to claim 1 or 2 , wherein the coating device is a liquid pool according to (22). Wherein upstream of the squeeze rolls (51, 52) of the metal strip (1) the apparatus for coating metal strip according to any one of claims 1 to 3 it was vertically movably installed in the vertical direction while sandwiching the.