JP5076215B2 - Curtain coater operation method - Google Patents

Abstract

The method involves moving application heads (1a, 1b) in an upstream, horizontal direction till the heads are provided in operation position and/or blow operation, when a curtain delivered by the application heads is stable. Mixture collecting tanks (3) are reclusively moved in a downstream direction, so that the curtain reaches a guide plate (B) made of a fiber web (w). The mixture collecting tanks are displaced to a standby position in such a manner that a rear edge of the tanks is positioned in the upstream direction than a lower edge (Bb) of the guide plate.

Description

  The present invention relates to a curtain coater operation method.

  Coated paper such as printing paper, pressure-sensitive paper, and thermal paper used for catalogs and the like is produced by applying a paint onto a web (base material) that is a base paper by a coater and then drying. A machine for applying a paint in this way is called a coating machine. Conventionally, such a coating machine employs a post-metering method in which excess paint is applied once on the web, and then scraped off with a blade or small-diameter rod or blown off with an air knife. Blade coaters, rod coaters, air knife coaters, etc. were the mainstream. However, in such post-metering coating, the paint penetrates the web a lot due to the hydraulic pressure when applying the paint to the web and the pressing force of the blade, etc., and maintenance due to wear of the blade and rod, etc. There are problems such as high costs.

  Therefore, in recent years, curtain coaters have been widely adopted in which a paint curtain film is ejected from a die (a chamber with a nozzle for producing a paint curtain film) onto a traveling web and applied onto the web. Curtain coaters have been used for a long time in fields such as photographic printing paper, but coating is stable due to air entrainment at high speed, bubbles mixed in paint, instability of paint curtain film due to insufficient mechanical accuracy, etc. Was not used in the paper industry.

  The present applicant has solved these problems, developed curtain coating technology as a stable technology, and has already supplied a large number of curtain coating machines to the whole world. Unlike conventional post metering type coating machines, curtain coating machines are easy to maintain because there are no consumables such as blades and rods, and the coating amount can be easily adjusted with high accuracy, and operability is good. There are features such as high effect of surface property improvement due to contour coating.

  On the other hand, there is a multi-layer curtain coater using two or more dies. FIG. 3 is a partial cross-sectional view of a coating apparatus for a two-layer curtain coater of the invention disclosed in Patent Document 1.

JP 2006-247611 A

As shown in the figure, the two-layer curtain coater of the present invention includes two dies 1a and 1b for spraying paints ta and tb flowing in the slits da and db downward, respectively, and the two dies 1a, The paint curtains ca and cb sequentially ejected from the surface 1b toward the slope Ba are stacked in order as the surface of the slope Ba is moved to form two paint layers ra and rb, and the lower end of the slope Ba And a guide plate B for transferring the paint layer onto the web w surface as two paint curtains ca and cb from the downward curtain guide part Bb. In this way, two coating layers sa (lower layer) and sb (upper layer) are formed on the running web w surface. In addition, the arrow is the advancing direction of the web w.

  By the way, in the case of such multilayer coating, it is necessary to let the coating material flow through the die for jetting the coating material before coating on the web. The paint spouted from the die is received by the paint catch pan and recycled. If it doesn't flow in advance, it will take a considerable amount of time from the start of pouring paint to the die until the temperature and viscosity become constant and a stable curtain is obtained. End up.

  In addition, when one die is stopped and the other die is used for operation, and then both die are used for operation, the internal paint dries when the operation of the stopped die is resumed. Therefore, the clogging of the slit is caused, and the slit shape becomes unstable due to the temperature change before and after supplying the paint. For this reason, warm water may be circulated for an appropriate time during or after the die is shut down.

  An operation method for solving such a problem is disclosed in Patent Document 1 described above. According to this method, depending on the quality of the product to be coated, it is possible to send or stop the paint of any die. The paint of the stopped die is dropped on the paint catch pan, and piping, pumps, etc. are used. Circulate. Also, cleaning can be performed by circulating hot water instead of the paint.

  FIG. 4 is an explanatory diagram of the operation method disclosed in Patent Document 1. In the figure, 1a, 1b and 1c are dies, ca, cb and cc are paint curtains ejected from each die, 2a, 2b and 2c are paint catch pans, B is a guide plate, Bb is a curtain guide and w is a web. . Reference numeral 3 denotes a paint catch pan of mixed paint from the curtain guide Bb.

  The figure (a) shows a paint curtain ca from the die 1a, a paint curtain cb from the die 1b, and a paint curtain cc from the die 1c in order on the guide plate B, and the web is formed as a three-layer paint curtain from the curtain guide Bb. It is transferred to the w plane for coating. In this case, the paint curtains ca, cb, cc are received by the paint catch pans 2a, 2b, 2c and are not circulated.

  In FIG. 2B, the paint curtain ca from the die 1a and the paint curtain cc from the die 1c are sequentially laminated on the guide plate B, and then transferred from the curtain guide Bb to the surface of the web w as a two-layer paint curtain. It is something to work on. In this case, the die 1b moves to the standby position, and the paint curtain cb is received and circulated by the paint catch pan 2b, or hot water is circulated instead of the paint.

    In FIG. 2C, the paint curtain cb from the die 1b and the paint curtain cc from the die 1c are laminated in order on the guide plate B, and then transferred to the surface of the web w as a two-layer paint curtain from the curtain guide Bb. It is something to work on. In this case, the die 1a moves to the standby position, and the paint curtain ca is received and circulated by the paint catch pan 2a, or warm water is circulated instead of the paint.

    In FIG. 4D, the paint curtain ca from the die 1a and the paint curtain cb from the die 1b are sequentially laminated on the guide plate B, and then transferred to the web w surface as a two-layer paint curtain from the curtain guide Bb. It is something to work on. In this case, the die 1c moves to the standby position, and the paint curtain cc is received and circulated by the paint catch pan 2c, or warm water is circulated instead of the paint. Although not shown in these drawings, before starting the operation of the curtain coater, the dies 1a, 1b, 1c are all in the standby position, and the paint curtains ca, cb, cc ejected from them are paints. It is received and circulated by catch pans 2a, 2b and 2c.

  By the way, the distance from the die 1 to the guide plate B is important. FIG. 5 is an explanatory diagram for explaining this. Although depending on the paint characteristics, if the distance s from the die 1 to the guide plate B is inappropriate, the flow rate is small, and the paint curtain c is thin, the paint curtain c has a surface tension. During the fall of its own weight, it breaks in the width direction and becomes a streaky flow.

In order to prevent such a phenomenon from occurring, the distance s from the die 1 to the guide plate B may be shortened to the distance s1 before the paint curtain c is broken in the width direction. When the amount is large, the coating layer r on the guide plate B is disturbed, and in particular, if the distance s from the downstream second layer die 1b to the guide plate B in FIG. 3 is too short, the upstream first layer. The paint layer ra on the guide plate B formed by the die 1a for use will be scratched.

  In order to cope with such a problem with respect to the driving method as shown in FIG. 4, when the die 1a, 1b, 1c is moved from the driving position to the standby position or moved from the standby position to the driving position, a diagram is shown. It is necessary to move not only horizontally but also vertically as shown in FIG. In addition, it is necessary to move all the dies at the start of operation, but mixing of the paint occurs during the movement, but the mixed paint cannot be recovered and reused.

  The present invention has been devised in view of such a problem of the prior art shown in FIG. 4, and it is only necessary to move horizontally when moving from the standby position of the die to the operating position. It is an object of the present invention to provide a method of operating a curtain coater that hardly causes mixing.

  In order to achieve the above object, the curtain coater operating method of the present invention comprises two dies that form paint curtains by jetting paint downward, and the paint curtains ejected from each die are sequentially received on the slope. A curtain coater having a guide plate that flows down along the web and moves from the lower curtain guide downward to the web surface as a two-layer paint curtain, and the position of each die can be adjusted in the web traveling direction. Before the start of the coater operation, each die waits in front of the guide plate to flow the paint, and below each die, the paint from the downstream die on the guide plate is poured. The downstream die paint catch pan for receiving and collecting, the upstream die paint catch pan for receiving and collecting the paint from the upstream die on the guide plate, and the like There is a mixed paint catch pan that is below and in the standby state with the rear end positioned behind the lower end of the guide plate. The downstream die paint catch pan and the mixed paint catch pan are in the web traveling direction. The position can be adjusted, and the downstream die paint catch pan has a slope, and it has a guide plate that flows the paint flowing down into the downstream die paint catch pan, and starts operation. Each die is moved horizontally until the lower end approaches the guide plate slope, while the downstream die paint catch pan is also moved closer to the upstream die paint catch pan, so that the downstream die is the upstream die. The guide plate prevents the paint flowing out from the downstream die from flowing into the upstream die catch catch pan while passing over the paint catch pan. And de, color curtain ejected from the die is adapted to retract Once stabilized, the coating mix catch pan forward.

    The distance between the lower end of each die during operation and the guide plate slope is preferably 0.1 to 100 mm.

The effects of the present invention are as follows.
Two upstream and downstream dies forming the paint curtain, and a guide for receiving the paint curtain ejected from each die on the slope in order and flowing down along the slope to make a two-layer paint curtain on the web surface In a curtain coater with a plate, before the coater starts operation, each die waits in front of the guide plate and flows paint, and each paint is received and collected by a paint catch pan. Each die is moved horizontally until the lower end approaches the guide plate slope, while the downstream die paint catch pan is also moved closer to the upstream die paint catch pan, and the downstream die is moved upstream. While passing over the side die paint catch pan, the paint that has flowed out of the downstream die by the guide plate attached to the downstream die paint catch pan. There guarded so as not to flow into the paint catching pan upstream die coating curtain ejected from the die becomes stable, the coating mix catch pan is retracted forward is adapted to normal operation. In this way, when the die is moved from the standby position to the operating position, only horizontal movement is required, and mixing of the paint hardly occurs during movement of the die.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
1 and 2 are side views of the curtain coater for explaining the operation method of the curtain coater of the present invention. FIG. 1 (a) shows a state in which two dies on the upstream side and downstream side are waiting, and the paint is flowing, respectively. FIG. 2 (b) shows two upstream and downstream dies. The die is positioned on the guide plate and is in operation. FIGS. 1B, 1C, and 2A show a state in which the two dies on the upstream side and the downstream side are moving to shift from the standby state to the operating state, respectively.

In these drawings, as shown in FIG. 2B, 1a is an upstream die and 1b is a downstream die. ca is a paint curtain ejected from the upstream die 1a, and cb is a paint curtain ejected from the downstream die 1b. 2a is a paint catch pan for the upstream die, 2b is a paint catch pan for the downstream die, 2c is attached to the paint catch pan for the downstream die, and the paint that has flowed down there is a paint catch for the downstream die It is a guide plate poured into the pan 2b. Reference numeral 3 denotes a mixed paint catch pan which is below the paint catch pans 2a and 2b and whose rear end is located behind the lower end of the guide plate B in the standby state. B is a guide plate, which sequentially receives the paint curtains ca, cb ejected from the dies 1a, 1b on the slope Ba, and flows down along the slope Ba, so that two layers of paint curtains ca, It moves to the web w surface as cb.

  As shown in FIG. 1A, two dies 1a and 1b on the upstream side and the downstream side are in a standby state, and are flowing through paint curtains ca and cb, respectively, and these are the paint catch pans 2a for the upstream die. And it is received by the downstream die paint catch pan 2b and circulated by a pump (not shown).

  Next, as shown in FIG. 1B, the upstream die 1 a, the downstream die 1 b, and the downstream die paint catch pan 2 b move horizontally toward the guide plate B. In this state, the paint curtain cb is continuously received by the downstream die paint catch pan 2 b and circulated by a pump (not shown), and the paint curtain ca is received by the mixed paint catch pan 3. Mixed paints are usually discarded because they cannot be recycled. The support devices for the upstream die 1a, the downstream die 1b, and the downstream die paint catch pan 2b move on a rail (not shown) provided horizontally along the curtain coater on both sides of the curtain coater. It has become.

  Next, as shown in FIG. 1C, the upstream die 1 a and the downstream die 1 b further horizontally move backward toward the guide plate B. In this state, the paint curtain cb flows down on the guide plate 2c, flows along the slope, and flows into the downstream die paint catch pan 2b. The paint curtain ca is received by the mixed paint catch pan 3.

  Next, as shown in FIG. 2 (a), the upstream die 1a and the downstream die 1b further horizontally move backward toward the guide plate B, and the upstream die 1a is located at the tip of the guide plate B. At the upper side, the paint curtain ca once flows down on the guide plate B, flows along the slope thereof, flows down from the curtain guide Bb, and is received by the mixed paint catch pan 3. The paint curtain cb leaves the guide plate 2 c and is received by the mixed paint catch pan 3.

  Next, as shown in FIG. 2 (b), the upstream die 1a and the downstream die 1b move horizontally further, and the lower ends of the upstream die 1a and the downstream die 1b are guide plates B, respectively. To the driving position. When the paint curtain ca and the paint curtain cb are stabilized, the mixed paint catch pan is retracted forward, and is transferred onto the web w surface as two-layer paint curtains ca and cb as shown in the figure. When stopping the operation, the procedure is reversed, and finally the hot water is circulated to clean the inside of the die and piping.

Next, the function and effect of this embodiment will be described.
Two dies 1a and 1b on the upstream side and downstream side that form the paint curtain c, and the paint curtains ca and cb ejected from each die are sequentially received on the slope Bb and flowed down along the slope to form a two-layer paint curtain. In the curtain coater having the guide plate B to be transferred onto the surface of the web w as ca and cb, the dies 1a and 1b wait in front of the guide plate B and flow the paint before the start of the operation of the coater. The paint catch pans 2a and 2b receive and collect the paint. When the operation is started, the die dies 1a and 1b are horizontally moved until the lower end approaches the guide plate slope, while the downstream die paint catch is collected. The pan 2b is also moved so as to approach the upstream die paint catch pan 2a, and the downstream die 1b is placed on the upstream die paint catch pan 2a. During the passage, the guide plate 2c attached to the downstream die paint catch pan 2b guards the paint cb flowing out from the downstream die 1b from flowing into the upstream die paint catch pan 2a, and each die 1a, 1b. When the paint curtains ca and cb ejected from the air are stabilized, the mixed paint catch pan 3 is retracted forward to perform normal operation. In this way, when the dies 1a and 1b are moved from the standby position to the operating position, only horizontal movement is required, and mixing of the paint hardly occurs during movement of the dies.

The present invention is not limited to the embodiments described above, and various modifications can be made without departing from the scope of the invention. For example, the moving direction of the web w may be the opposite direction to FIG. 1 or FIG. Although the upstream die paint catch pan 2a has been described as being fixed, it may be moved horizontally. Further, the two dies 1a and 1b on the upstream side and the downstream side have been described as being used. However, a fixed die may be provided further upstream of the upstream die 1a to form a three-layer type. .

It is explanatory drawing for demonstrating the operating method of the curtain coater of this invention. It is explanatory drawing for demonstrating the operating method of the curtain coater of this invention. 2 is a partial cross-sectional view of a two-layer curtain coater disclosed in Patent Document 1. FIG. It is explanatory drawing of the conventional curtain coater operating method disclosed by patent document 1. FIG. It is explanatory drawing that the distance from die | dye to a guide plate is important.

Explanation of symbols

1a upstream die 1b downstream die 2a upstream die paint catch pan 2b downstream die paint catch pan 2c guide plate 3 mixed paint catch pan B guide plate Ba guide plate slope Bb curtain guide

Claims (2)

  Two dies that form paint curtains by spraying paint downward, and two layers from the curtain guide facing downward at the lower end, receiving the paint curtains ejected from each die on the slope in sequence. A curtain coater having a guide plate to be transferred onto the web surface as a paint curtain, wherein each die can be adjusted in position in the web traveling direction. Waiting in front of the guide plate, the paint is poured, and below each die, the paint catch pan for the downstream die that receives and collects the paint from the downstream die on the guide plate, and the guide plate The upstream die paint catch pan that receives and collects paint from the upstream die on the upper side, and the rear end is lower than the lower end of the guide plate in the standby state below them A mixed paint catch pan located at the rear is provided, and the position of the downstream die paint catch pan and the mixed paint catch pan can be adjusted in the web traveling direction. Has a guide plate that is inclined and flows the paint flowing down into the paint catch pan for the downstream die. When starting operation, each die moves horizontally until the lower end approaches the guide plate slope. In the meantime, the downstream die paint catch pan is also moved so as to approach the upstream die paint catch pan, and the downstream die is moved by the guide plate while the downstream die passes over the upstream die paint catch pan. When the paint curtain ejected from each die is stabilized, it is mixed. Curtain coater method of operating, characterized in that is adapted to retract the charge catch pan forward.   2. The curtain coater operating method according to claim 1, wherein the distance between the lower end of each die and the guide plate slope during operation is 0.1 to 100 mm.

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