JPH03207471A - Method for coating resin at high velocity - Google Patents

Abstract

PURPOSE:To obtain a final product at the large amounts at low cost by maintaining a relation for satisfying a specified formula among the amount of a resin soln. discharged from a nozzle, the opening width of the slit of the nozzle, the coated width in the width direction of a metallic band and the distance between the opening part of the nozzle and the metallic band. CONSTITUTION:A nozzle 2 is arranged for the face to be coated of a traveling metallic band (steel strip) 5. The opening part 3 of the nozzle 2 is extremely approached to the metallic band 5 and also a resin soln. 1 is supplied to the nozzle 2. The liquid reservoir of the resin soln. 1 is formed to the opening part 3 of the nozzle. The metallic band 5 is coated by the meniscus formed between the resin soln. 1 and the metallic band 5. In this case, coating is performed by maintaining a relation for satisfying a formula y.s.w.60/x <=30000 (musec) among the amount x (l/min) of the resin soln. discharged from the nozzle 2, the opening width s (mm) of the slit of the nozzle, the coated width w (mm) in the width direction of the metallic band and the distance y (mm) between the opening part 3 of the nozzle and the metallic band 5. The high-speed coating can be provided in a plating line and therefore a final product is obtained at the large amounts at low cost.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention relates to a method of coating a metal band (plate) (hereinafter simply referred to as metal band) with a resin film at high speed.
More specifically, hot-rolled steel sheets, cold-rolled steel sheets, Zn, Aj, which are widely used as materials for construction, electrical equipment, and cans.
, Sn. This invention relates to a method for producing a resin-coated material on a metal plate coated with Pb or an alloy of these metals. (Conventional technology) The conventional resin coating method is to coat the copper strip with alkali,
The so-called roll coater method is generally used, in which the copper strip is continuously coated with a solution of the resin to be coated on the copper strip using a roll after the surface has been cleaned by pickling or chemical treatment. In this method, a resin solution is placed in a container called a pan, and a pick-up roll scoops up the resin solution from the pan and transfers the resin solution to an ablation roll that comes into contact with the toning band to coat the toning band. The coating thickness is controlled by adjusting the circumferential speed of the big-up roll, the circumferential speed of the application roll, the gap between the rolls, and the belt running speed, and the viscosity of the resin solution is controlled to be kept constant during coating. This roll coater method is a widely used coating method today, and materials coated on steel plates or surface-treated steel plates are used for cans, construction, and electrical equipment. (Problems to be Solved by the Invention) The disadvantages of this roll coater method are that a roll pattern called roving is likely to occur, and the coating is prone to cracks, dents, etc. due to bubbles from the resin solution when it is blown up from the pan. Since defects are particularly likely to occur during high-speed coating, there is a limit to increasing the speed, and an example of high-speed coating is said to be 100 to 150 m/win (Tadashi Matsudaira: "Industrial Coating Technology" 477, Sachi Shobo Publishing (1977)
)). In addition, the abricating rolls that come into contact with the rope strips are prone to scratches due to burrs at the ends of the steel strips, and schedule management is required to gradually narrow the width from the wide sea bream strips to the narrow steel strips. Changing the type requires a long time for cleaning and preparation, which also poses problems in workability.

A curtain flow coater has been proposed and put into practical use as a method to solve these drawbacks of roll coaters.

This method does not use a roll that comes into contact with the copper strip, but instead pours the resin solution from a slit in a curtain shape and applies it to the running strip. Because it does not use a roll, coating defects such as roving marks, repellents, and dents occur. The film has excellent uniformity. In addition, since no rolls are used, there is no need to manage schedules for changes in the width of the steel strip, and when changing the type of resin, multiple slits can be provided to quickly change the type of resin. Although there are such advantages, in terms of efficiency, the belt running speed is 100 to 16 as an example of high speed.
0 m/min (Tadashi Matsudaira: “Industrial painting technology,
477, Sachi Shobo Publishing (1977)) There are limits.
This is because the air conveyed by the toning belt gets caught up in the resin solution at the contact point between the curtain and the toning belt, causing paint film breakage.

There is also a method of controlling the film thickness by immersing the belt in a resin solution or spraying the resin solution onto the belt and squeezing out the excess resin solution, but the line speed (travel speed of the belt) is 160 m/sin. If this is exceeded, there is a limit to how high the speed can be increased because the resin solution that has been squeezed out will be violently scattered and adhere to the adjustment belt as a splash, and foaming caused by gas being involved in the resin solution can lead to coating defects. Next, U.S. Patent No. 3,201,275 proposes a method that solves the above problem, but this method uses capillary action to suck up the resin solution from the resin solution whose liquid level is lower than the coating nozzle. Coating is performed by forming a meniscus of resin solution on the nozzle and contacting it with the tape. This method causes the following problems. As the belt traveling speed increases, the supply speed of the resin solution to be supplied increases accordingly, and the amount of resin solution sucked up by capillary action is insufficient, causing coating film breakage on the coating surface. It is easy to imagine that sufficient liquid can be supplied if the resin solution is supplied using a known metering pump, but even in this case, the atmospheric gas (
Generally speaking, air) collides with the meniscus and the air is drawn into the meniscus, causing paint film breakage and putting a limit on high-speed coating.

The object of the present invention is to provide a high-speed resin coating method that can completely eliminate the drawbacks of the conventional methods as described above.

(Means for Solving the Problems) The present inventors have perfected the present invention as a result of various studies on high-speed resin coating methods. That is, the gist of the present invention is as follows. (1) Distributing a nozzle against the coating surface of a running metal strip, bringing the opening of the nozzle very close to the metal strip, and supplying a resin solution to the nozzle so that the resin solution is poured into the nozzle opening. In a method of coating a metal band with a meniscus formed between the resin solution and the metal band by forming a pool, the amount of resin solution discharged from the nozzle
(liters/min), nozzle slit opening width S (mm), coating width in the metal strip width direction W (mm), and distance y (mm) between the nozzle opening and the metal strip, maintaining a relationship that satisfies the following formula. A high-speed resin coating method characterized by coating.

y-s-W・60/x≦30000 (2) Arrange a nozzle against the coating surface of the traveling metal band, bring the opening of the nozzle very close to the metal band, and supply the resin solution to the nozzle. In the method of forming a pool of resin solution at the nozzle opening and coating the metal band with a meniscus formed between the resin solution and the metal band, the amount of resin solution discharged from the nozzle
(liters/min), nozzle slit opening length S (mm), metal strip width direction cloth width W (mm), and distance y (mm) between the nozzle opening and the metal strip that satisfies the following formula. A high-speed resin coating method characterized in that the atmospheric gas conveyed by the metal band is sucked through a gas suction port provided at the upper side of the nozzle in the direction in which the metal band runs. y-s-w・60/x≦30000 The present invention will be explained based on FIG. 1, which shows an example of the plating method according to the present invention. In the present invention, a water or organic solvent solution or emulsion liquid 1 containing the resin to be coated is supplied from a known metering bomb or pressurized extrusion container to a nozzle 2 provided with a slit-shaped opening 3. Slit opening 3
A steel strip 5 to be coated with resin is placed on the opposite side of the steel strip 5 via a support roll 4.
is run close to the opening 3. The nozzle 2 is provided with a suction port 6 on the upper side of the opening 3 in the running direction of the copper strip to suck in the atmospheric gas that is carried along with the running of the strip. In such a configuration, the amount of resin solution discharged from the nozzle x (
j! /win), the nozzle slit opening width S (11, coating width in the sea bream band width direction w (saw), and the distance between the nozzle opening and the sea bream band y (ms), the meniscus can be determined by satisfying the following relationship. It is possible to form a stable shape and obtain a uniform coating.y-s-w・60/x≦30000 (u SEC
) It was experimentally confirmed that under conditions other than this relationship, the coating becomes streaky and a uniform coating film cannot be obtained. In other words, it is shown that the larger the amount of resin solution discharged from the nozzle, the smaller the nozzle slit opening width S, and the smaller the distance y between the nozzle opening and the adjustment zone, the easier it is to obtain a uniform coating. Next, the above relationship shows that the belt running speed is 1 0
If it exceeds 0 m/win, it becomes less intimidating. This is because the atmospheric gas (air) carried by the adjustment band gets caught up in the meniscus and causes the paint film to break. To prevent this, the transported atmospheric gas is sucked through the suction port 6. The required suction air volume varies greatly depending on the distance between the suction port and the copper strip, but when the nozzle slit surface and the suction port surface are aligned on the same surface, it is 0. The suction air volume may be 5 m'/Hr or more, preferably lm'/Hr or more.

Next, the present invention will be explained with reference to examples.

(Example) Fig. 1 shows one example of the method of implementing the present invention, in which a steel strip 5
The surface has been cleaned by alkaline degreasing or further pickling treatment, and examples of nozzle arrangement for horizontal and vertical travel are also shown. The running of the steel strip 5 is stabilized with a support roll 4, and a resin coating nozzle 2 is installed on the opposing surface. On the upper side of the steel strip 5 in the running direction on the same surface, the carrier gas suction port 6 is installed continuously or divided in the width direction of the sea bream strip. These nozzles 2, suction ports 6
is placed close to the steel strip 5, a commercially available metering pump is connected to the nozzle 2, and the resin liquid 1 to be applied is sent to the nozzle.
In addition, a commercially available suction blower is connected to the suction port 6. An example of coating with water-soluble resin in such a device structure will be described. The steel strip 5 has a thickness of O. '2 msi,
A nozzle with a width of 500 sv+ was used, and the resin coating nozzle 2 had a gap of 1- in the slit opening and was made by Nobu 490 Izuen. Similarly, the carrier gas suction port 6 used had a gap of 5 cm and a width of 490 cm. Copper strip running speed 100 m
/sin = discharge amount of resin liquid 14! /win (set thickness 2On), the distance between the coating nozzle and the coating band is l
A uniform coating was obtained with less than one coat. When the running speed of the copper strip was set to 300 m/+min, the coating broke due to air entrainment, so uniform coating was achieved by suctioning the carrier air from the strip at a suction air volume of Im'/Hr from the carrier gas suction port. Obtained. At this time, the distance between the suction port and the adjustment belt was 1lIml. This suction port can be divided into multiple parts in the width direction of the copper strip, and the suction air volume distribution in the width direction of the copper strip can be changed depending on the coating ink condition to facilitate practical operation. Moreover, the viscosity of the resin liquid used is 50 to 500 cP. Table 1 summarizes the coating conditions and uniform coating properties studied. Furthermore, according to the present invention, cleaning can be easily performed when changing the resin liquid. (Effects of the Invention) According to the present invention, high-speed coating of resin liquid can be installed in a plating line, and a large quantity of final products can be obtained at low cost, making it possible to efficiently respond to the recent increase in demand. In addition, it is easy to change the resin type, and it is possible to quickly respond to the diverse demands of customers.

[Brief explanation of drawings]

Figure 1 is a diagram showing an example of the plating method according to the present invention. 1...Resin liquid, 2...Coating nozzle, 3...
- Slit-shaped opening, 4... Support roll, 5... Steel strip, 6... Conveyance air suction port.

Claims (2)

[Claims] (1) Arranging a nozzle against the coating surface of a running metal band, bringing the opening of the nozzle very close to the metal band, and supplying a resin solution to the nozzle to form a pool of the resin solution at the nozzle opening. In the method of coating the metal band with a meniscus formed between the resin solution and the metal band, the amount of resin solution discharged from the nozzle
(liter/min), nozzle slit opening width s (mm), coating width in the metal strip width direction w (mm), and distance between the nozzle opening and the metal strip y (mm), maintaining a relationship that satisfies the following formula: A high-speed resin coating method characterized by coating. y・s・w・60/x≦30000 (2) Arranging a nozzle against the coating surface of the traveling metal band, bringing the opening of the nozzle very close to the metal band, and supplying a resin solution to the nozzle to form a pool of the resin solution at the nozzle opening. In the method of coating the metal band with a meniscus formed between the resin solution and the metal band, the amount of resin solution discharged from the nozzle
(liter/min), nozzle slit opening width s (mm), coating width in the metal strip width direction w (mm), and distance between the nozzle opening and the metal strip y (mm), maintaining a relationship that satisfies the following formula: Furthermore, the high-speed resin coating method is characterized in that atmospheric gas conveyed by the metal band is sucked through a gas suction port provided in the nozzle in the direction in which the metal band travels. y・s・w・60/x≦30000