JP4461796B2 - Continuous coating method and continuous coating apparatus - Google Patents

Description

  The present invention relates to a continuous coating method and a continuous coating apparatus for applying a paint to a strip-like object to be coated such as a steel strip, and further coating the paint.

  In various steel strips including a galvanized steel strip, in order to improve corrosion resistance and lubricity at the time of pressing, a chromate treatment liquid, a lubricant-containing resin, and the like are applied to the surface. A method of continuous coating with a roll coater is used for coating a strip-shaped object such as a steel strip. The roll coater has the advantage that the strip-shaped object can be continuously coated at a relatively high speed, and the amount of paint applied to the belt-shaped object can be easily controlled.

  Roll coaters are roughly classified into a natural roll coater method and a reverse roll coater method depending on the rotation direction of the applicator roll of the roll coater. In the natural roll coater method, the applicator roll rotates so that the traveling direction of the surface of the applicator roll is the same as the traveling direction of the strip-shaped object at the contact portion between the applicator roll and the belt-shaped object. ing. On the other hand, in the reverse roll coater method, the rotation direction of the applicator roll is opposite to that of the natural roll coater method, and the surface of the applicator roll is in contact with the applicator roll and the belt-shaped object. The applicator roll rotates so that the traveling direction is opposite to the traveling direction of the belt-shaped object. The reverse roll coater method is generally used because it has a feature that a uniform coating amount can be stably obtained, a coating finish is good, and it is suitable for relatively thick film coating.

However, when the belt-like object is continuously coated with a roll coater, a streak pattern called roping is likely to occur in the longitudinal direction of the belt-like object, and this roping becomes a coating defect of the belt-like object. Roping is likely to occur with a natural roll coater type roll coder, and even with the reverse roll coater method, although the frequency of occurrence is reduced, roping may still occur.
Using a reverse roll coater type roll coater as a technology to continuously paint the belt-like object while preventing the occurrence of roping, the belt-like object is pre-painted with the paint blown from the nozzle, and the pre-painted paint is There is a continuous coating method and a continuous coating apparatus (prior art 1) in which a paint having a target film thickness is applied by a roll coater before drying and curing (refer to Patent Document 1).

Similarly, as another technology for continuously coating a strip-shaped object while preventing the occurrence of roping using a roll coater of the reverse roll coater method, a paint applied to the surface of the pickup roll is used as a pickup roll and a metering roll. After passing through the gap between the applicator roll and the surface of the applicator roll, after transferring from the surface of the applicator roll to the surface of the belt-shaped object to be coated, after contact with the belt-shaped object There is a continuous coating method and a continuous coating apparatus (conventional technology 2) in which a coating material is supplied from a nozzle on the surface of an applicator roll before contacting the pickup roll (see Patent Document 2).
JP-A-63-119876 Japanese Patent Laid-Open No. 11-262710

  However, in the continuous coating method and the continuous coating apparatus of Prior Art 1, since the paint blown out from the nozzle preliminarily coats the belt-shaped object, the paint blown out from the nozzle at the start of the preliminary coating or at the end of the preliminary coating is removed. There is a problem in that it easily falls down or scatters to the periphery, and the bottom and periphery of the nozzle are contaminated with paint. In particular, when the belt-shaped object is a steel band and the steel band is transported by a vertical pass line, the steel band transport roll existing below the nozzle is contaminated by the falling paint, This can cause paint defects. In addition, if the amount of paint blown from the nozzle is large, the amount of paint that falls or scatters also increases, so it is necessary to adjust the amount of paint blown from the nozzle, and this adjustment work is complicated.

Moreover, the continuous coating method and the continuous coating apparatus of the prior art 2 are effective in suppressing the occurrence of roping, and no roping detected by visual observation is lost. However, when the continuously coated belt-like object is microscopically examined, there may be fine unevenness in the coating film thickness. Depending on the type of paint, the effect of suppressing the occurrence of roping may be small, and it may not be possible to fully cope with the occurrence of roping.
The present invention has been made to eliminate the above-mentioned problems of the prior art, and the object of the present invention is that the belt-shaped object can be continuously coated without any coating defects, and the surrounding area is contaminated with the paint. It is providing the continuous coating method and continuous coating apparatus which can prevent.

The present invention has the following configuration in order to solve the problem. In the continuous coating method according to the first aspect of the present invention, the coating material is preliminarily coated on the upstream side of the belt-like object to be conveyed along the pass line, and after the preliminary coating, the coating material is applied by the applicator roll of the roll coater on the downstream side. A continuous coating method in which paint is overflowed from a nozzle installed immediately below a pre-painting roll, and the paint is adhered to the surface of the rotating pre-painting roll directly above the nozzle. The surface of the pre-painted roll thus adhered is brought into contact with the surface of the belt-like object to be coated, and the surface of the pre-painted roll is brought into contact with the surface of the belt-like object at the contact position between the surface of the pre-painted roll and the surface of the belt-like object. The preliminary coating is performed by causing the coating body to travel in the direction opposite to the traveling direction of the coating body and transferring the coating material from the surface of the preliminary coating roll to the surface of the belt-shaped body.

According to the invention of claim 1, since the strip-shaped object is pre-painted by the pre-coating roll and then the main coating is performed by the applicator roll of the roll coater, the coating state of the belt-shaped object is uniform and beautiful. Become.
Also, in the pre-coating, the paint overflows from the nozzle and adheres to the surface of the pre-coating roll, so if the amount of paint overflowing from the nozzle is adjusted, the paint will drop or scatter from the nozzle or pre-coating roll Is easily prevented, and peripheral devices are also easily prevented from being contaminated by prepainted paint.

In addition, it does not matter whether the pass line for transporting the belt-like object is a vertical pass line or a horizontal pass line. In particular, when the belt-like object is conveyed by the vertical pass line, a preliminary coating roll and a nozzle are used. It is easy to prevent the peripheral devices below from being contaminated by the paint.
Examples of the paint include various paints such as a chromate treatment liquid, a lubricant-containing resin, and a coloring paint.

A continuous coating method according to a second aspect of the present invention is the continuous coating method according to the first aspect, wherein the band-shaped object has a contact position between the surface of the preliminary coating roll and the surface of the band-shaped object. When the weld passes, the surface of the preliminary coating roll is separated from the surface of the belt-shaped object.
When a plurality of steel strip coils are continuously supplied to the continuous coating apparatus, a weld is present on the surface of the steel strip. This weld is raised on the surface of the belt-like object to be coated, and the pre-coating roll collides with the rise of the weld and the pre-coating roll jumps easily. In this case, stable contact between the surface of the preliminary coating roll and the surface of the belt-shaped object to be coated may be hindered. In such a case, the transfer of the coating material from the surface of the preliminary coating roll to the surface of the belt-shaped object is hindered, resulting in a coating defect of uneven coating. When the strip-shaped object is conveyed at a high speed and the speed of continuous coating is increased, the coating unevenness is increased. In addition, the surface of the preliminary coating roll may be damaged due to the rise of the weld and the contact with the preliminary coating roll.

According to the invention of claim 2, when the welded portion that rises on the surface of the belt-shaped object is conveyed to a position where the pre-painting roll is located, the surface of the pre-painting roll is separated from the surface of the belt-shaped object. The coating roll does not collide with the welded part, and the contact between the surface of the prepainted roll and the surface of the belt-like object is prevented from being disturbed by the welded part. Such coating defects do not occur.
Here, when the welded portion of the belt-shaped object is passed through a position where the applicator roll is located, if the surface of the applicator roll is separated from the surface of the belt-shaped material, the applicator roll is formed in the vicinity of the welded portion. This coating is preferable because it does not cause coating defects such as coating unevenness and does not damage the applicator roll.

The continuous coating method according to the invention of claim 3 is the continuous coating method according to claim 1 or 2, wherein a tank is provided at a higher position than the nozzle, and the position of the liquid level of the paint in the tank is constant. The paint is made to flow from the tank to the nozzle due to the difference in height between the tank and the nozzle, and the supplied paint overflows from the nozzle.
According to the invention of claim 3, the tank is located higher than the nozzle, and the paint in the tank flows to the nozzle and overflows from the nozzle due to the difference in height between the tank and the nozzle. Since the position of the paint liquid level in the tank is constant, the height difference between the paint liquid level in the tank and the nozzle is also constant, and the flow rate of the paint to the nozzle is also kept constant. The amount of paint overflowing from the container is also kept constant. Since the amount of paint overflowing from the nozzle is kept constant, the amount of paint adhering to the surface of the pre-coating roll is also constant, and pre-coating with the pre-coating roll is performed under the same stable conditions.

In addition, since a certain amount of paint overflows from the nozzle, even if a part of the paint falls without adhering to the preliminary painting roll, it can be easily received by a liquid pan or the like. it can. Further, since the paint overflows without being blown from the nozzle, the paint does not scatter around. Therefore, it is possible to easily prevent peripheral devices and the like from being contaminated with the paint.
The liquid level of the paint in the paint tank is easily controlled by a method such as overflowing the paint, and is kept constant.

According to a fourth aspect of the present invention, there is provided a continuous coating apparatus in which a preliminary coating apparatus preliminarily coats a strip-shaped object to be transported along a pass line on the upstream side, and after the preliminary coating, a roll coater of the present coating apparatus on the downstream side. The applicator roll has a continuous coating apparatus for coating the paint, and the preliminary coating apparatus rotates in a direction opposite to the traveling direction of the belt-shaped object at a contact position with the surface of the belt-shaped object. And a nozzle that is installed directly under the preliminary coating roll and supplies the overflowing paint to the preliminary coating roll directly above .
According to the invention of claim 4, the invention of claim 1 can be implemented. Therefore, the belt-like object is pre-painted by the pre-coating roll in the pre-coating device, and the main paint is applied by the applicator roll of the roll coater in the pre-coating device, so that the coating state of the belt-like object is uniform and beautiful. . Further, by adjusting the amount of paint overflowing from the nozzle, it is possible to easily prevent peripheral devices from being contaminated by the paint.

A continuous coating apparatus according to a fifth aspect of the present invention is the continuous coating apparatus according to the fourth aspect, wherein the preliminary coating roll is configured to be detachable from the surface of the belt-shaped object.
According to the invention of claim 5, the invention of claim 2 can be implemented. Therefore, it is prevented that the coating defect such as coating unevenness occurs in the preliminary coating and the main coating due to the welded portion.
A continuous coating apparatus according to a sixth aspect of the invention is the continuous coating apparatus according to the fourth or fifth aspect, wherein the continuous coating apparatus is located higher than the nozzle and the position of the liquid level of the internal paint is kept constant. The tank has a tank for supplying the paint to the nozzle in accordance with the height difference from the nozzle, and for overflowing the paint from the nozzle.
According to the invention of claim 6, the invention of claim 3 can be implemented. Therefore, the flow rate of the coating material to the nozzle is kept constant, the overflow amount of the coating material from the nozzle is also kept constant, and the preliminary coating by the preliminary coating roll is performed under the same stable condition. In addition, the paint does not scatter, and the falling paint can be easily received, and contamination of peripheral devices and the like with the paint is easily prevented.

  Since the present invention is a continuous coating method and a continuous coating apparatus as described above, a continuous coating method and a continuous coating apparatus capable of continuously coating a belt-shaped object without coating defects and preventing the surroundings from being contaminated with paint. There is an effect that can be provided.

The best mode for carrying out the present invention will be described with reference to FIGS.
As shown in FIG. 1, there is a vertical pass line 10 of a steel strip S which is a strip-shaped object, and the steel strip S is configured to be continuously transported at a predetermined speed from an upstream side to a downstream side by a pair of transport rolls 12. ing. The steel strip S has a plurality of welds 14 on the surface, and each weld 14 is raised on the surface of the steel strip S.
A sensor 16 is installed on the upstream side of the transport roll 12, and a continuous coating apparatus is installed on the downstream side of the transport roll 12. The sensor 16 is configured to be able to detect the welded portion 14 of the steel strip S conveyed along the vertical pass line 10.

The continuous coating apparatus includes a pair of preliminary coating apparatuses 22, a pair of main coating apparatuses 40 and a paint circulation apparatus 60, and the preliminary coating apparatus 22 is located on the upstream side of the vertical pass line 10 with respect to the main coating apparatus 40. And the steel strip S conveyed by the vertical pass line 10 is pinched | interposed between a pair of preliminary coating apparatus 22 and between a pair of this coating apparatus 40. FIG.
Of the pair of preliminary coating apparatuses 22, one preliminary coating apparatus 22 will be described.
As shown in FIG. 2, one preliminary coating apparatus 22 includes a preliminary coating roll 24 a, a nozzle 26, and a liquid receiving pan 28.
The preliminary coating roll 24 a is a rubber roll whose surface is covered with rubber, and is axially fixed to the roll chock 30. The roll chock 30 is mounted on the slider 34 of the first linear motion guide device, and the roll chock 30 is continuous with the first piston cylinder 32.

  Further, the first piston cylinder 32 is connected to the sensor 16, and when the sensor 16 detects the welded portion 14, the first piston cylinder 32 is moved at a timing when the detected welded portion 14 reaches a contact position Xa1 described later. The pre-coating roll 24a, the roll chock 30 and the slider 34 are integrally moved by being guided by the guide rail 36 of the first linear motion guide device, and the surface of the pre-coating roll 24a is separated from the surface of the steel strip S. When the welded portion 14 passes through the contact position Xa1, the surface of the preliminary coating roll 24a comes into contact with the surface of the steel strip S.

The preliminary coating roll 24a is configured to be capable of reverse rotation in the direction opposite to the traveling direction of the steel strip S. That is, when the surface of the preliminary coating roll 24a and the surface of the steel strip S are in contact with each other, the traveling direction of the surface of the preliminary coating roll 24a is opposite to the traveling direction of the steel strip S at the contact position Xa1. In the direction, the preliminary coating roll 24a is configured to be rotatable.
The nozzle 26 is located immediately below the preliminary coating roll 24 a, and the roll chock 30 supports the nozzle 26. The nozzle 26 is integrated with the preliminary coating roll 24a via the roll chock 30, and the relative positional relationship between the nozzle 26 and the preliminary coating roll 24a is fixed, and the preliminary coating roll 24a is a guide rail of the linear motion guide device. When guided and moved by 36, the nozzle 26 is also moved together. The nozzle 26 is connected from an upper tank 66 described later by a supply line 76a.

The liquid receiving pan 28 is a tray opened upward, and is located below the preliminary coating roll 24 a and the nozzle 26. The liquid receiving pan 28 has an area sufficient for the moving preliminary coating roll 24a and the nozzle 26 to be always positioned above. The liquid receiving pan 28 is connected by a return line 78a to the lower tank 62 described later.
Of the pair of pre-coating devices 22, the other pre-coating device 22 has the same configuration as the one of the pre-coating devices 22 described above, and has the same pre-coating roll 24b, nozzle 26, and liquid receiving pan 28 as the pre-coating roll 24a. And have.

However, the position where the preliminary coating roll 24 b is installed with respect to the vertical pass line 10 is shifted to the downstream side from the position where the preliminary coating roll 24 a is installed with respect to the vertical pass line 10. That is, as shown in FIGS. 1 and 2, the contact position Xa1 between the surface of the preliminary coating roll 24a and the surface of the steel strip S is more than the contact position Xa2 between the surface of the preliminary coating roll 24b and the surface of the steel strip S. , Upstream.
Each main coating apparatus 40 is a roll coater having an applicator roll 42, a pickup roll 44, a metering roll 46, and a paint pan 48.

  The applicator roll 42 is a rubber roll whose surface is covered with rubber, and is fixed to a slider of a second linear motion guide device (not shown), and this slider is also connected to a second piston cylinder (not shown). The second piston cylinder is connected to the sensor 16, and when the sensor 16 detects the welded portion 14, the second piston cylinder is operated at a timing when the detected welded portion 14 reaches a contact position Xb described later, and the application When the trolley 42 moves while being guided by the guide rail of the second linear motion guide device, the surface of the applicator roll 42 moves away from the surface of the steel strip S, and the welded portion 14 passes through the contact position Xb, the applicator roll The surface of 42 is in contact with the surface of the steel strip S.

Similarly to the preliminary coating rolls 24a and 24b, the applicator roll 42 is configured to be capable of reverse rotation in the direction opposite to the traveling direction of the steel strip S. That is, when the surface of the applicator roll 42 and the surface of the steel strip S are in contact with each other, the traveling direction of the surface of the applicator roll 42 is opposite to the traveling direction of the steel strip S at the contact position Xb. In the direction, the applicator roll 42 is configured to be rotatable.
The pickup roll 44 is a metal roll whose surface is chrome-plated, and the surface of the pickup roll 44 and the surface of the applicator roll 42 are in contact with each other at the contact position Xc. The pick-up roll 44 is configured to be rotatable in the same direction as the rotating direction of the applicator roll 42 that comes into contact.

  The paint pan 48 is a receiving tray opened upward, and has a paint tank 50 and a paint discharge part 52, and the paint tank 50 and the paint discharge part 52 are partitioned by a weir 54. The paint tank 50 is connected from the discharge side of a pump 64, which will be described later, by a discharge line 74 and a supply line 76b. The paint discharge section 52 has a discharge port for the paint P at the bottom, and returns to the lower tank 62. It is connected by 78b. The pickup roll 44 is located immediately above the paint tank 50, and the height position of the lower end of the pickup roll 44 is lower than the height position of the upper end of the weir 54. The applicator roll 42 and the metering roll 46 are also located above the paint tank 50, and the paint tank 50 has an area sufficient for the moving applicator roll 42 to always be located above the paint tank 50. ing.

  The metering roll 46 is a metal roll whose surface is chrome plated, and the surface of the metering roll 46 and the surface of the pickup roll 44 are close to each other with a gap G at the proximity position Xg. The position of the metering roll 46 can be adjusted, and the size of the gap G can be adjusted by adjusting the position of the metering roll 46. The rotation direction of the metering roll 46 is the same as the rotation direction of the pickup rolls 44 arranged close to each other.

The paint circulation device 60 includes a lower tank 62, a pump 64, and an upper tank 66. The lower tank 62 that stores the paint P is connected to the return line 78a from the liquid receiving pan 28, and is connected to the return line 78b from the paint discharge part 52 of the paint pan 48. 70 is connected by a return line 78c.
The pump 64 has a suction side connected to the lower tank 62, and a discharge side connected to a storage tank 68 of the upper tank 66, which will be described later, by a discharge line 74. A supply line 76 b branches off from the middle of the discharge line 74 and is connected to the paint tank 50 of the paint pan 48. A flow valve 80c is installed in the discharge line 74 on the downstream side of the branch point, and a flow valve 80b is installed in the supply line 76b.

  The upper tank 66 is installed at a higher position than each nozzle 26 of each preliminary coating apparatus 22, and has a storage tank 68 and a paint discharge part 70 inside, and between the storage tank 68 and the paint discharge part 70. Are partitioned by a weir 72. The storage tank 68 is connected to the nozzle 26 by a supply line 76a. The paint discharge part 70 is connected to the lower tank 62 by a return line 78c. A flow valve 80a is installed in the supply line 76a.

The height of the upper end of the weir 72 is variable, and the height difference h between the nozzle 26 and the upper end of the weir 72 is configured to be adjustable.
The present embodiment is configured as described above, and the operation thereof will be described next.
The pump 64 of the continuous coating apparatus is activated, and the paint P in the lower tank 62 is discharged to the discharge line 74 by the pump 64. Part of the paint P discharged to the discharge line 74 flows through the discharge line 74 as it is and continuously flows into the storage tank 68 of the upper tank 66. The remaining paint P discharged to the discharge line 74 flows through the supply line 76 b and continuously flows into the paint tank 50 of the paint pan 48.

  When the paint P continuously flows into the storage tank 68 of the upper tank 66 by the pump 64, the paint P overflows from the storage tank 68 and overflows the weir 72 and overflows into the paint discharge unit 70. Accordingly, the storage tank 68 is always filled with the paint P, and the position of the liquid level of the paint P in the storage tank 68 is always the higher nozzle of the nozzles 26 of the preliminary coating apparatuses 22. It is kept at a position higher than 26 by h. The flow rate of the paint P from the pump 64 to the storage tank 68 is kept constant by the flow valve 80c.

  The coating material P in the storage tank 68 located higher than each nozzle 26 flows from the storage tank 68 to the nozzle 26 through the supply line 76a because there is at least a difference in height from the nozzle 26. The flow rate of the paint P flowing through the supply line 76a is kept constant by the flow valve 80a. Since there is at least a difference in level between the liquid level of the paint P in the storage tank 68 and the nozzle 26, the flow rate of the paint P flowing through the supply line 76a can be easily adjusted by adjusting the opening of the flow valve 80a. . Further, by adjusting the height of the upper end of the weir 72, the height difference between the liquid level of the coating material P in the storage tank 68 and each nozzle 26 can be easily adjusted. Therefore, the flow rate of the paint P flowing through the supply line 76a can be easily and strictly controlled.

The paint P that has flowed from the storage tank 68 to the nozzles 26 overflows from the nozzles 26 and adheres to the surfaces of the preliminary coating rolls 24 a and 24 b immediately above the nozzles 26. Since the flow rate of the coating material P flowing to the nozzle 26 can be easily controlled by adjusting the flow valve 80a, the overflow amount of the coating material P overflowing from the nozzle 26 can be easily controlled and adhered to the surfaces of the preliminary coating rolls 24a and 24b. The amount of paint P to be controlled can be easily controlled.
The paint P overflowed to the paint discharge part 70 of the upper tank 66 flows through the return line 78 c and flows into the lower tank 62.

  When the paint P continuously flows into the paint tank 50 of the paint pan 48 by the pump 64, the paint P overflows from the paint tank 50, overflows the weir 54, and overflows to the paint discharge unit 52. Therefore, the paint tank 50 is always filled with the paint P, and the liquid level of the paint P in the paint tank 50 is kept constant. The flow rate of the paint P to the paint tank 50 is kept constant by the flow valve 80b. Further, the flow rate of the paint P to the paint tank 50 is always sufficient if the paint P overflows beyond the weir 54 of the paint pan 48, and strict control of the flow rate is not required. Therefore, the flow rate of the paint P to the paint tank 50 can be easily controlled by adjusting the flow valve 80b.

The paint P overflowed to the paint discharge part 52 of the paint pan 48 flows through the return line 78 b and flows into the lower tank 62.
The steel strip S is continuously transported from the downstream side to the upstream side by the transport roll 12 and enters between the pair of preliminary coating apparatuses 22.
In one preliminary coating apparatus 22, the surface of the preliminary coating roll 24a is in contact with the surface of the steel strip S at the contact position Xa1, and the preliminary coating roll 24a rotates reversely in the direction opposite to the traveling direction of the steel strip S. Yes. The paint P overflowing from the nozzle 26 adheres to the surface of the preliminary painting roll 24a, and the paint P adhering to the surface of the preliminary painting roll 24a is transferred to the surface of the steel strip S at the contact position Xa1. The

Even in the other preliminary coating apparatus 22, the surface of the preliminary coating roll 24b is in contact with the surface of the steel strip S at the contact position Xa2 downstream of the contact position Xa1, and the preliminary coating roll 24b is in the traveling direction of the steel strip S. And reverse rotation in the opposite direction. The paint P overflowing from the nozzle 26 adheres to the surface of the preliminary painting roll 24b, and the paint P adhering to the surface of the preliminary painting roll 24b is transferred to the surface of the steel strip S at the contact position Xa2. The
At the contact position Xa1 and the contact position Xa2, the steel strip S is pre-coated on both sides, and the pre-coated steel strip S is conveyed to the downstream main coating apparatus 40.

When the steel strip S is conveyed along the vertical pass line 10, the welded portion 14 of the steel strip S is detected by the sensor 16. When the sensor 16 detects the welded portion 14, a control device (not shown) detects that the detected welded portion 14 passes through the contact position Xa1 based on the conveyance speed of the steel strip S and the distance between the sensor 16 and the contact position Xa1. The timing is calculated, and at this timing, the first piston cylinder 32 of one of the preliminary painting apparatuses 22 is operated, and the preliminary painting roll 24a, the roll chock 30 and the slider 34 are integrated into the guide rail of the first linear motion guide apparatus. 36, the surface of the preliminary coating roll 24a moves away from the surface of the steel strip S at the contact position Xa1. When the welded portion 14 passes through the contact position Xa1, the surface of the preliminary coating roll 24a comes into contact with the surface of the steel strip S again at the contact position Xa1. Therefore, at the contact position Xa1, the preliminary coating roll 24a does not collide with the welded portion 14 and jump up, and the preliminary coating with the preliminary coating roll 24a is not hindered by the welded portion 14.

  At the same time, when the sensor 16 detects the welded portion 14, a control device (not shown) detects that the detected welded portion 14 is in the contact position from the conveyance speed of the steel strip S and the distance between the sensor 16 and the contact position Xa 2. The timing of passing through Xa2 is calculated, and at this timing, the first piston cylinder 32 of the other preliminary coating device 22 is operated, and the preliminary coating roll 24b, the roll chock 30 and the slider 34 are integrated into the first linear motion guide. The surface of the preliminary coating roll 24b moves away from the surface of the steel strip S at the contact position Xa2. When the welded portion 14 passes through the contact position Xa2, the surface of the preliminary coating roll 24b comes into contact with the surface of the steel strip S again at the contact position Xa2. Therefore, at the contact position Xa2, the preliminary coating roll 24b does not collide with the welded portion 14 and jump up, and the preliminary coating with the preliminary coating roll 24b is not hindered by the welded portion 14.

  In the preliminary painting apparatus 22, the paint P overflowing from the nozzle 26 adheres to the surfaces of the preliminary painting rolls 24a and 24b, so that the paint P falls or scatters even when the preliminary painting is started or stopped. There is nothing to do. Even if the paint P may fall from the nozzle 26, it is preferable to install the liquid receiving pans 28 below the preliminary coating rolls 24a and 24b so that the dropped paint P can be received. Further, even if a part of the coating P adhering to the surfaces of the preliminary coating rolls 24a and 24b may fall from the preliminary coating rolls 24a and 24b, if the liquid receiving pan 28 is installed, the coating P is similarly dropped. The received paint P is received. The nozzle 26 and the preliminary coating rolls 24a and 24b are moved by the movement of the first piston cylinder 32. If the liquid receiving pan 28 is always provided below the nozzle 26 and the preliminary coating rolls 24a and 24b, the nozzle 26 Even if the paint P falls from the preliminary painting rolls 24 a and 24 b, the dropped paint P enters the liquid receiving pan 28. Therefore, the paint P overflowing from the nozzle 26 does not contaminate the lower transport roll 12. Further, since the paint P only overflows from the nozzle 26 and does not blow out from the nozzle 26, the paint P does not scatter from the nozzle 26, and peripheral devices such as the preliminary coating rolls 24a and 24b exit the nozzle 26. The paint P is not contaminated.

The paint P that has entered the liquid receiving pan 28 flows to the lower tank 62 through the return line 78a.
Further, since the overflow amount of the paint P overflowing from the nozzle 26 can be controlled easily and strictly, it is possible to easily prevent the paint P from dripping from the nozzle 26 and the preliminary coating rolls 24a and 24b.
Furthermore, since the contact position Xa1 between the surface of the preliminary coating roll 24a and the surface of the steel strip S is located upstream of the contact position Xa2 between the surface of the preliminary coating roll 24b and the surface of the steel strip S, The surface of the preliminary coating roll 24a and the surface of the preliminary coating roll 24b are prevented from contacting each other. Therefore, the width of the coating P adhering to the surfaces of the preliminary coating rolls 24a and 24b is larger than the width of the steel strip S, and a part of the coating P on the surface of the preliminary coating rolls 24a and 24b is attached to the surface of the steel strip S. Even if it remains without wearing, the surfaces of the preliminary coating rolls 24a and 24b do not come into contact with each other and the paint P remaining on the respective surfaces does not scatter.

The steel strip S, which has been applied with a certain amount of paint P and finished preliminary coating, is continuously conveyed from below to above the vertical pass line 10 and enters between the pair of main coating apparatuses 40.
In the coating apparatus 40, the surface of the applicator roll 42 is in contact with the pre-coated surface of the steel strip S at the contact position Xb, and the applicator roll 42 reversely rotates in the direction opposite to the traveling direction of the steel strip S. is doing.

  Since the lower end of the pick-up roll 44 of the coating apparatus 40 is at a lower position than the upper end of the weir 54 of the paint pan 48, it is immersed in the paint P in the paint tank 50 of the paint pan 48. The paint P inside adheres to the surface of the pickup roll 44. The pickup roll 44 rotates, and the paint P adhering to the surface of the pickup roll 44 reaches the proximity position Xg. In the proximity position Xg, the paint P adhering to the surface of the pickup roll 44 passes through the gap G between the metering roll 46 and the pickup roll 44 and has a predetermined thickness. The paint P having a predetermined thickness rotates with the pickup roll 44 and is conveyed to a contact position Xc where the pickup roll 44 and the applicator roll 42 are in contact with each other. Transcribed. The coating P having a predetermined thickness transferred to the surface of the applicator roll 42 rotates with the applicator roll 42 and reaches the contact position Xb between the surface of the applicator roll 42 and the surface of the steel strip S. At the contact position Xb, the paint P having a predetermined thickness attached to the surface of the applicator roll 42 is transferred onto the preliminary coating on the surface of the steel strip S. And the steel strip S transfers the coating material P from the applicator roll 42, and complete | finishes this coating. The steel strip S that has been subjected to the main coating is conveyed by the vertical pass line 10 to the next step downstream of the continuous coating apparatus.

  Further, when the sensor 16 detects the welded portion 14, a control device (not shown) detects that the detected welded portion 14 determines the contact position Xb from the conveyance speed of the steel strip S and the distance between the sensor 16 and the contact position Xb. When the second piston cylinder is operated at this timing, the surface of the applicator roll 42 is separated from the surface of the steel strip S, and the welded portion 14 of the steel strip S passes the contact position Xb. The surface of the applicator roll 42 comes into contact with the surface of the steel strip S again. Therefore, the applicator roll 42 does not collide with the welded portion 14 and jump up at the contact position Xb, and the main coating by the applicator roll 42 is not hindered by the welded portion 14.

Therefore, the steel strip S is pre-painted by the pre-coating device 22 and is also pre-coated by the main coating device 40, and the pre-coating and the main coating are not obstructed by the welded portion 14. The coating state of the steel strip S conveyed downstream is uniform, beautiful and free of coating defects.
In the present coating apparatus 40, even if the paint P adhering to the applicator roll 42, the pick-up roll 44, and the metering roll 46 falls down, the dropped paint P is received by the paint tank 50 of the paint pan 48. It is done. Although the applicator roll 42 moves due to the movement of the second piston cylinder, there is always a paint tank 50 below the applicator roll 42, and even if the paint P falls from the moving applicator roll 42, it dropped. The paint P enters the paint tank 50. Therefore, the coating material P adhering to the applicator roll 42, the pickup roll 44, and the metering roll 46 does not contaminate the preliminary coating apparatus 22 and the transport roll 12 below.

In the present embodiment, the rotation direction of the metering roll 46 is the same as the rotation direction of the pickup roll 44 arranged in proximity, but instead the rotation direction opposite to that of the pickup roll 44 arranged in proximity. Of course, this is possible.
Further, in the present embodiment, the height of the upper end of the weir 72 of the upper tank 66 is variable, but instead, the installation height of the upper tank 66 is configured to be variable, and the paint P in the storage tank 68 is configured. It is also possible to adjust the height difference between the liquid level and each nozzle 26.

Next, it reports on the continuous coating test of the steel strip S which the inventor implemented.
In this test, as Invention Examples 1 to 4, a continuous coating apparatus having the same configuration as that of the present embodiment was used, and a paint was continuously coated on a steel strip. Further, as Comparative Examples 1 to 4, except that the preliminary coating portion was not provided, a continuous coating apparatus having the same configuration as that of the present embodiment was used, and the paint was continuously coated on the steel strip.
Each continuously coated steel strip is a galvanized steel strip conveyed by a vertical pass line, and the plate thickness is 0.7 mm and the plate width is 1200 mm. The paint applied to the steel strip was a resin-containing chromate aqueous solution, and the target value of the wet film thickness after the main coating was 10 μm. The viscosity of the aqueous chromate resin solution is approximately the same as the viscosity of water.

The preliminary coating roll of the continuous coating apparatus used in Invention Examples 1 to 4 is a rubber roll, and the roll diameter is 200 mm. Moreover, the applicator roll, the pick-up roll and the metering roll of the present coating apparatus used in Invention Examples 1 to 4 are the applicator roll, the pick-up roll and the applicator roll which the present coating apparatus of the continuous coating apparatus used in Comparative Examples 1 to 4 has. Same as a metering roll. That is, the applicator roll is a rubber roll, and the roll diameter is 300 mm. The pickup roll is a metal roll, and the roll diameter is 300 mm. The metering roll is a metal roll, and the roll diameter is 150 mm. In Invention Examples 1 to 4 and Comparative Examples 1 to 4, the size of the gap between the pickup roll and the metering roll at the close position was set to 100 μm.
In Invention Examples 1 to 4 and Comparative Examples 1 to 4, the steel strip transport speed, the pre-coating roll, the pick-up roll, the metering roll, the rotation speed of each surface of the applicator roll, and the flow rate of the paint to the nozzle of the pre-coating apparatus Were set to the values shown in Table 1 below.

The steel strips continuously coated with paints in Invention Examples 1 to 4 and Comparative Examples 1 to 4 were inspected for the occurrence of roping and the results shown in Table 1 were obtained. That is, roping occurred in each steel strip of Comparative Examples 1 to 4, but no roping occurred in each steel strip of Invention Examples 1 to 4. Therefore, it was confirmed that the steel strip can be continuously coated without causing roping by the continuous coating apparatus using the continuous coating method according to the present invention.
Furthermore, after continuously coating paint on steel strips in Invention Examples 1 to 4, the presence or absence of paint splashing around the continuous coating device was investigated, but the paint splashing around the continuous coating device including transport rolls and sensors was investigated. Was not recognized.

It is a block diagram of the continuous coating apparatus which concerns on this invention. It is a block diagram of a preliminary coating apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Vertical pass line 12 Conveyance roll 14 Welding part of steel strip 16 Sensor 22 Preliminary coating device 24a, 24b Preliminary coating roll 26 Nozzle 28 Liquid receiving pan 30 Roll chock 32 First piston cylinder 34 Slider 36 Guide rail 40 This coating device 42 Application Tarol 44 Pickup Roll 46 Metering Roll 48 Paint Pan 50 Paint Tank 52 Paint Pan Discharge Port 54 Paint Pan Weir 60 Paint Circulator 62 Lower Tank 64 Pump 66 Upper Tank 68 Reservoir 70 Upper Tank Paint Discharge Port 72 Upper tank weir 74 Discharge line 76a, 76b Supply line 78a, 78b, 78c Return line 80a, 80b, 80c Flow rate valve h Difference in level between the liquid level in the storage tank and the nozzle G Gap between adjacent parts P Paint S Steel strip Xa1 , Xa2 Xb Contact position between coating roll surface and steel strip surface Xb Contact position between applicator roll surface and steel strip surface Xc Contact position between pickup roll surface and applicator roll surface Xg Proximity between metering roll surface and pickup roll surface position

Claims (6)

A continuous coating method in which paint is pre-painted on the upstream side of the belt-like object to be conveyed on the pass line, and after the pre-coating, the paint is finally coated on the downstream side by an applicator roll of a roll coater,
The paint is allowed to overflow from the nozzle installed immediately below the preliminary coating roll, and the paint is adhered to the surface of the rotating preliminary coating roll directly above the nozzle ,
The surface of the preliminary coating roll to which the paint is attached is brought into contact with the surface of the belt-shaped object to be coated,
In the contact position between the surface of the preliminary coating roll and the surface of the belt-shaped object, the surface of the preliminary coating roll is advanced in the direction opposite to the traveling direction of the belt-shaped object, and the paint is removed from the surface of the preliminary coating roll. A continuous coating method, wherein the preliminary coating is performed by transferring the surface of a belt-shaped object to be coated.   Separating the surface of the preliminary coating roll from the surface of the belt-like object when the welded portion of the belt-like object passes through the contact position between the surface of the preliminary painting roll and the surface of the belt-like object. The continuous coating method according to claim 1, wherein the method is a continuous coating method.   A tank is provided at a higher position than the nozzle, the position of the liquid level of the paint in the tank is kept constant, and the paint is supplied by flowing from the tank to the nozzle due to the difference in height between the tank and the nozzle. The continuous coating method according to claim 1, wherein the paint overflows from the nozzle. The pre-coating device pre-paints the belt-like object to be transported on the pass line on the upstream side, and after the pre-coating, the applicator roll of the roll coater of the coating device on the downstream side continuously paints the paint. A painting device,
The pre-coating apparatus is installed at a position in contact with the surface of the belt-shaped object to be rotated in a direction opposite to the traveling direction of the belt-shaped object, and is installed immediately below the pre-coating roll and overflows. A continuous coating preliminary apparatus, comprising: a nozzle that supplies the coating material to the preliminary coating roll directly above .   The continuous coating apparatus according to claim 4, wherein the preliminary coating roll is configured to be detachable from the surface of the belt-shaped object.   A tank that is positioned higher than the nozzle, the position of the liquid level of the internal paint is kept constant, and the paint is made to flow and supply to the nozzle due to the height difference from the nozzle, and the paint overflows from the nozzle. The continuous coating apparatus according to claim 4 or 5, characterized by comprising:

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