JP4454690B1 - Bar coating head and bar coating apparatus using the same - Google Patents

Abstract

[PROBLEMS] To provide a compact bar coating head capable of precisely realizing a thin layer coating even with a wide width without causing the coating bar surface to be damaged by a foreign substance such as a filler or a paste of the coating liquid. A bar coating apparatus is provided.
SOLUTION: Using a rotatable coating bar in which a groove is spirally formed on the surface of a rod, a coating liquid is supplied to a supply side manifold and a drainage on one side wall in a width direction of the supply side manifold. A coating liquid supply hole for supplying the inside of the side manifold is provided, and the coating liquid inside the liquid supply side manifold is sent from one end side in the width direction to the other end side by a thrust force generated by the rotation of the bar. The bar forming head is configured by arranging the bars so that the groove forming directions are aligned.
[Selection] Figure 7

Description

  The present invention relates to a bar coating head that applies a coating liquid thinly and precisely to a flexible support (hereinafter referred to as “web”) such as a wide plastic film or paper that runs continuously by a coating bar. And a bar coating apparatus using the same. In the present invention, the term “wide” refers to those having a coating width of up to about 3500 mm, the term “thin layer” refers to those having a wet film thickness of 5 μm or less, and the term “precision” refers to unevenness or foreign matter on the thin layer coating. This means that there are no scratches due to the above.

  Conventionally, various types of apparatuses for applying a coating liquid to a continuously running web are known, and one of them is a bar coating apparatus. As this bar coating apparatus, for example, as disclosed in Patent Document 1, a rolling bar is used as a coating bar of the coating head, or as disclosed in Patent Document 2, The thing using the wire bar for the bar for coating is known.

  In recent years, advanced functions of display devices have progressed, and accordingly, optical functional films having thin and precise coating films such as antireflection films and polarizing films, or thin film films used as protective films for electronic devices, etc. Demand for high performance films is increasing. In addition, the high-functional film is required to have a large area that can be adapted to increase in size (for example, 2000 to 3000 mm width).

  Therefore, in order to produce a high-performance film having such a thin layer and a precise coating film, a coating apparatus using the above-described bar coating head, and in particular, a coating apparatus using a wire bar coating head has been widely used. It is coming.

  FIG. 1 is a front sectional view showing a general configuration of a wire bar coating head 100 used in this wire bar coating apparatus. That is, the wire bar coating head 100 includes a wire bar 103 for coating in which a wire 101 is spirally wound around a rod 102 and a groove formed between the wires 101 is spirally formed on the surface, and a base 104. A backup 105 that is erected at the center of the web running direction and rotatably supports the wire bar 103, and is provided upstream and downstream of the backup 105, and between the backup 105 and the supply side manifold 106 and the drain side The liquid supply side coater block 108 and the drainage side 109 which form the manifold 107 are comprised.

  The coating liquid 111 is provided with an arrow from the coating liquid supply hole 110 in the liquid supply side manifold 106 (in Patent Document 2, as will be described later, the coating liquid supply hole 110 is provided at the center in the width direction of the liquid supply side manifold 106). The coating liquid 111 passes through the gap t formed by the tip of the liquid supply side coater block 108 and the wire bar 103 due to the rotation of the wire bar 103 in the direction of arrow N as shown in FIG. 103 is pulled up by capillarity from the capillary groove formed between the wires 101, and the applied liquid 111 that has been pulled up appears as beads on both sides of the web 112, and a necessary amount is applied to the excess liquid 111. Is returned to the drain side manifold 107, and the remaining excess coating liquid 111 flows to the outside of the wire bar coating head 100. There.

  Here, the amount of the coating liquid 111 pulled up by the wire bar 103 is the size of the capillary formed by the diameter of the wire 101 of the wire bar 103, the characteristics of the coating liquid 111 pulled up, the rotational speed of the wire bar 103, the traveling speed of the web 113, etc. Determined by.

  According to the coating apparatus using the wire bar coating head 100 configured as described above, it is easy to handle and is advantageous for uneven speed as compared with a coating apparatus using another type of coating head. Since a good coating film is obtained, it has been conventionally used for coating having a coating width of about 600 to 1800 mm.

By the way, since the high-functional film described above is a thin layer having a dry film thickness of 0.2 to 1 μm and a wet film thickness of 2 to 3 μm, the necessary coating solution 111 is a small amount of ² to 3 ml / m ² . For example, even if the coating width is 3000 mm, the required amount of the coating liquid 111 is 6 to 9 ml per meter, and the actual coating width is 3000 mm and the coating speed is 100 m / min. It is.

  Applying such a small amount of the coating liquid 111 uniformly and evenly over the entire width direction of the wire bar 103, particularly the wire bar 103 widened and lengthened to cope with the increase in size described above, is the following that the coating liquid 111 itself has. Considering these problems, it was extremely difficult.

  It has been confirmed that the solvent-type solution has poor fluidity as compared with a general aqueous solution, and it is difficult to reach the full width with a small amount of liquid when the flow path is narrowed. As a result, stagnation can occur in the flow path, and aggregation can occur due to concentration changes due to partial evaporation of the solvent, and silicas and calcium carbonate placed in the coating liquid 111 to improve the optical function can be obtained. There is a problem that the fillers such as particles become large particles due to aggregation and damage the surface of the wire 101, thereby making it impossible to apply precisely.

  Originally, the filler itself has a size of about several μm, and hardly harms the wire bar 103 while being uniformly dispersed in the coating liquid 111. Therefore, this problem can be solved if the coating liquid 111 supplied from the coating liquid supply hole 110 to the liquid supply side manifold 106 is uniformly fed without being agglomerated without being agglomerated, but as described above. In the thin layer coating, since the flow rate of the coating liquid 111 is very small, it is easy for the coating liquid 111 to stagnate and agglomerate easily. It was extremely difficult.

  Further, once the excess coating liquid 111 collected in the drain side manifold 107 is mixed with the new liquid in the drain side manifold 107, it passes between the wire bar 103 and the backup 105, and the liquid supply side manifold 106. In addition, since the solvent in the liquid mixture is somewhat evaporated and the concentration is high, the liquid mixture tends to agglomerate and the filler particles become large, which causes the wire bar 103 and the backup 105 to move. In between, the wire bar 103 was damaged. In precision thin layer coating, when the distance between the closely wound wires 101 is increased by about 2 μm, stripes and the like appear. However, the damage caused by the large-sized filler exceeds this, which is a serious problem.

  When the coating liquid 111 stays inside the liquid supply side manifold 106, not only the above-described aggregation of the coating liquid 111 occurs, but also the concentration unevenness of the coating liquid 111 occurs in the staying portion as described later. It has been investigated by the present inventor that when the coating liquid 111 is applied to the web 112, coating unevenness occurs in the coating film.

  In view of the above circumstances, it seems that research on the coating liquid 111 that does not easily aggregate is being promoted in this field. However, it is not easy to improve the coating liquid 111, particularly the coating liquid 111 for high-functional films. Seems to be the case.

  Therefore, conventionally, various measures have been taken to deal with damage to the wire bar 103 as follows.

  For example, as a measure for preventing damage to the surface of the wire 101, it has been proposed to apply HCr (hard chrome) plating or DLC (diamond-like carbon) coating to the surface of the wire 101. However, the wire bar 103 subjected to such a process is quite expensive, and therefore, there is a problem that the manufacturing cost of the wire bar coating head 100 itself, and thus the whole wire bar coating apparatus using the same is greatly increased. It was hard to accept.

  Further, as a measure for evenly spreading the coating liquid 111 to the inside of the liquid supply side manifold 106, the coating liquid supply hole 110 has a system as shown in the above-mentioned Patent Document 2, that is, a cross-sectional plan view in FIG. As shown in FIG. 2, in addition to the method provided on the front wall at the center in the width direction of the liquid supply side manifold 106, as shown in FIG. 2B, the method provided on the side walls at both ends in the width direction of the liquid supply side manifold 106, Also, as shown in FIG. 2 (C), a plurality of systems are provided on the front wall in the width direction of the liquid supply side manifold 106. Further, as shown in the front sectional view of FIG. Provided on the side wall of one end portion in the width direction of the manifold 106, and in the vicinity of the coating liquid supply hole 110, the bottom wall of the liquid supply side manifold 106 is expanded to have a large area and the area is reduced toward the other end side. The method to do is taken To have.

  However, in the method of FIG. 2A, when the coating liquid 111 is supplied from the coating liquid supply hole 110 into the liquid supply side manifold 106, the wire 102 and the wire 102 are rotated in accordance with the rotation of the wire bar 103 described later in the arrow N direction. The stagnation P of the coating liquid 111 as shown in the figure is likely to occur near the coating liquid supply hole 110 in the direction opposite to the direction F of the thrust force generated by the viscous resistance of the coating liquid 111. In the method of FIG. The stagnation P of the coating liquid 111 is likely to occur near the central portion in the width direction of the liquid supply side manifold 106 where the coating liquid 111 collides, and the method of FIG. 2C is similar to the method of FIG. In addition, it is easy to stagnate the coating liquid 111 in the vicinity of each coating liquid supply hole 110 in the direction reverse to the direction F of thrust force, and in the method shown in FIG. The easily it, or the like can stagnate P of the coating solution supply hole 110 of the exit of the coating liquid 111 downward, has been clarified by the present inventors.

  The stagnation P of the coating liquid 111 inside the liquid supply side manifold 106, that is, the stagnation of the coating liquid 111 appears as partial density unevenness. Furthermore, as described above, the filler is turned into large particles having a high hardness, so that the above-described problem still cannot be solved.

  Furthermore, as a problem peculiar to thin layer coating with a wet film thickness of 5 μm or less in the wire bar coating method, the coating liquid 111 foams and foams adhere to the contact surface between the wire bar 103 and the web 112 that runs continuously, As a result, the quality of the coating film is impaired. As a result of the study of the mechanism of the generation of bubbles, the following facts have been investigated.

  That is, as described above, according to the wire bar coating head 100, the gap t formed by the tip of the liquid supply side coater block 108 and the wire bar 103 is formed by the coating liquid 111 by the rotation of the wire bar 103 in the arrow N direction. And is pulled up by a capillary phenomenon from a capillary groove formed between the wires 101 tightly wound around the rod 102 of the rotating wire bar 103, and the pulled coating liquid 111 becomes a bead on both sides applied to the web 112. The required amount is applied and the excess coating liquid 111 is returned to the drain side manifold 107. At this time, the coating liquid 111 is moved to the liquid supply side by the rotation of the wire bar 103 inside the drain side manifold 107. Therefore, the coating liquid 111 tends to be insufficient, that is, the pressure inside the drain side manifold 107 is liquid supply. Has become lower than the pressure inside the manifold 106, is an entity that part of the excess coating solution 111 is always in the state easy drawn into the interior of the liquid supply side manifold 106. For this reason, in the case of wire bar coating with a thick wet film thickness, only a part of the surplus coating liquid 111 is drawn into the liquid supply side manifold 106, but when the wet film thickness is small, the drain side The amount of the coating liquid 111 flowing to the surface of the liquid supply side manifold 106 is reduced, and when the excess coating liquid 111 is drawn into the liquid supply side manifold 106, it is entrained together with the air of the surplus liquid surface layer, and this air layer is interposed between the wire bar 103 and the backup 105. It is considered that bubbles are generated by mixing with the coating liquid 111 when passing through the liquid supply side manifold 106.

  The above is the case where the coating head is a wire bar coating head, but also in the rolling bar coating head, the rolling bar for coating has a spiral groove on the surface of the rod, Since it has the same configuration as the wire bar and has substantially the same operational effects, it has the same problems as the wire bar coating head.

JP 2007-061709 A JP 2007-32080 A

  The present invention has been made in view of the above-described circumstances, and an object of the present invention is to remove the above-described drawbacks of the conventional bar coating head and the bar coating apparatus using the same, and to apply the coating liquid caused by the retention of the coating liquid. Concentration unevenness of the bar, damage to the bar surface due to large particles of fillers and fillers caused by aggregation or precipitation, and further generation of bubbles on the coated surface are prevented, respectively, and thin layer coating is precise even with a wide width The present invention provides a compact bar coating head and a bar coating apparatus using the same.

  The object of the present invention is to form a spiral groove on the surface of the rod, to apply a coating liquid to a continuously running web, and to stand upright on a base and to support the bar rotatably. And a liquid supply side coater block and a liquid discharge side coater block which are provided on the base on the upstream side and the downstream side of the backup and form a liquid supply side manifold and a liquid discharge side manifold between the backup and the backup respectively. A coating liquid supply hole for supplying a coating liquid to the inside of the liquid supply side manifold and the drainage side manifold is provided on one end side wall in the width direction of the liquid supply side manifold, and The groove forming direction is aligned with the direction in which the coating liquid in the liquid supply side manifold is sent from one end side to the other end side in the width direction by the thrust force generated by the rotation of the bar. It is accomplished by providing a bar coating head, characterized by comprising arranging the bar.

  Further, the above object of the present invention is to provide the liquid supply side manifold so that at least one second coating liquid supply hole having substantially the same configuration as the coating liquid supply hole is directed in the direction of feeding the coating liquid. This is achieved effectively by providing a bar coating head characterized in that it is provided on the liquid supply side front wall.

  The above object of the present invention is effectively achieved by providing a bar coating head characterized in that the coating liquid supply hole is provided near the bottom wall of the liquid supply side manifold.

  In addition, the above object of the present invention is such that a second bar having substantially the same structure as the coating bar is rotatably provided in the liquid supply side manifold or the drain side manifold. It is effectively achieved by providing a bar coating head characterized by

  Further, the above object of the present invention is to provide a second bar and a third bar having substantially the same structure as the coating bar in the liquid supply side manifold and the drain side manifold, respectively. Effectively achieved by providing a bar coating head that is rotatably provided and has a pressure inside the drain side manifold set higher than a pressure inside the liquid side manifold. Is done.

  In addition, the object of the present invention is to provide a bar coating head characterized in that the second bar and / or the third bar are rotated in conjunction with the coating bar during coating. Is more effectively achieved.

  Further, the object of the present invention is that the coating bar is any one of a wire bar, a rolling bar, and a D-bar (product name of OSG System Products Co., Ltd.). This is effectively achieved by providing a head.

  The above object of the present invention is effectively achieved by providing a bar coating head characterized in that the coating head is a closed type and the coating liquid is a solvent type coating liquid.

Furthermore, the object of the present invention is to provide a bar characterized in that the bar coating head according to any one of the above is incorporated, and the coating liquid is applied to the continuously running web by the bar coating head. This is accomplished by providing a coating device.
The at least one second coating liquid supply hole having substantially the same configuration as the coating liquid supply hole is directed toward the direction in which the coating liquid is sent from one end side to the other end side in the width direction. This is effectively achieved by providing a bar coating head characterized by being provided on the liquid supply side front wall of the side manifold.

  The present inventor conducted experiments as in Example 1 to be described later with respect to the relationship between the formation direction of grooves formed in a spiral shape on the surface of the rod (that is, the spiral winding direction) and the behavior of the solution in bar coating. As a result, when this coating bar is rotated in the solution, a groove is formed on the rod surface in a spiral shape, so that a thrust force is generated by the viscous resistance of the solution and the rod surface, thereby forming the groove. Depending on whether the direction (spiral winding direction) is clockwise or counterclockwise with respect to the rod, the solution is moved either forward or backward in the axial direction of the bar, and the bar rotates. Found that the solution was stirred.

  Since the action of moving the solution by the coating bar having the spiral groove formed on the surface, that is, the liquid feeding action is similar to the action by the liquid feeding pump, in the present invention, The action is called “pumping action”, and the effect of this action is called “pumping effect”.

  In addition, since the above-mentioned bar rotates, the solution is sticky and the solution is entangled with this bar and stirred. The function of such a bar is just in the emulsification and dispersion step when making the solution. Since this function is similar to the function of the diffusion plate, this action is called “dispersion action”, and the effect of this action is called “dispersion effect”.

  As will be described later, this pumping effect is small when the solution is a simple aqueous solution, but becomes very high when the solution is a solvent-type coating solution, and increases as the rotation speed of the coating bar increases. Has been revealed.

  The present invention has been made by paying attention to the above-described pumping action and its effect, and the dispersion action and its effect. According to the present invention, the following effects can be obtained.

  That is, according to the present invention, the pumping effect in the flow path by a general pump is most effective immediately after the liquid supply hole by adopting the above-described configuration, and the effect is reduced by the flow path resistance when moving away from it. Then, since the pumping effect by the bar for coating appears over the entire length of the inside of the manifold, the pressure is constant in the whole part. For this reason, the coating liquid does not stay inside the liquid supply side manifold, and further, agglomeration is prevented by a synergistic effect with the dispersing action of the coating bar, so that the generation of fillers and nozzles is eliminated. The surface of the bar will not be damaged. In addition, since a uniform coating solution can be applied uniformly over the entire width direction of the coating bar, thin layer coating can be performed precisely even with a wide width. Furthermore, since the shape of the manifold for storing the coating liquid can be simplified and the size thereof can be reduced, the entire apparatus can be made compact, thereby providing an inexpensive apparatus.

  In particular, a second bar and a third bar having substantially the same structure as the coating bar are rotatably provided inside the liquid supply side manifold and the drain side manifold, respectively, In the invention in which the pressure inside the side manifold is set higher than the pressure inside the liquid supply side manifold, it is possible to set so that the coating liquid of the drain side manifold is always pushed out from the gap t little by little. Even in the case of layer coating, it is possible to prevent air from being entrained together with the liquid that is refluxed to the drainage side, thereby almost eliminating the generation of bubbles.

It is front sectional drawing which shows the general structure of a wire bar application head. (A) (B) (C) It is plane sectional drawing which shows the behavior of the coating liquid in the liquid supply side manifold of the conventional wire bar coating head. It is front sectional drawing which shows the behavior of the coating liquid in the liquid supply side manifold of the conventional wire bar coating head. It is front sectional drawing of the wire bar coating head which concerns on Example 1 and 2 of this invention. (A) (B) It is sectional drawing which shows the relationship between the winding direction of the wire in a wire bar, and the moving direction of a coating liquid. It is a front sectional view of the wire bar application head concerning Example 3 of the present invention. It is a plane sectional view of the wire bar application head concerning Example 4 of the present invention. It is a front sectional view of the wire bar application head concerning Example 5 of the present invention. It is a front sectional view of the wire bar application head concerning Example 6 of the present invention. It is a front sectional view of the wire bar application head concerning Example 7 of the present invention.

  Hereinafter, the content of the present invention will be described based on an example using a wire bar coating head as an example. Note that the present invention is not necessarily limited to the following examples, and it goes without saying that the configuration can be variously changed without departing from the scope of the claims.

  Regarding the relationship between the winding direction of the wire in the wire bar for coating and the behavior of the coating liquid, an open type wire bar coating head 200 as shown in a front sectional view in FIG. A confirmation experiment was conducted.

  In this wire bar coating head 200, a wire bar 203 having a length of 400 mm formed by tightly winding a wire 201 having a diameter of 100 μm around a rod 202 having a diameter of 8 mm is rotatably set on an upper portion of a backup 205 standing on a base 204. The liquid supply side manifold 206 and the liquid discharge side manifold 207 are formed on the upstream side and the downstream side of the backup 205 via the liquid supply side coater block 208 and the liquid discharge side coater block 209, respectively.

  Using this wire bar coating head 200, a solvent-based coating liquid 211 made of polyester is supplied from the coating liquid supply hole 210 to the liquid supply side manifold 206 and the drain side manifold 207, and the wire bar 203 is rotated by a rotating means (not shown). Is rotated in the direction of arrow N at a rotation speed of 300 rpm, and the behavior of the coating liquid 211 is confirmed from above the apparatus, and the wire 201 is wound around the rod 202 in a spiral shape. , The thrust force acts in the axial direction of the wire bar 203 due to the adhesion resistance between the surface of the wire 201 and the coating liquid 211, and the coating liquid 211 moves in the axial direction of the wire bar 203. The moving direction, that is, the direction in which the thrust force acts is different depending on the winding direction of the wire 201, and FIG. As shown, when the wire 201 is wound in the same direction (W ′ direction shown in the figure) with respect to the rod 202 rotating in the arrow N direction (clockwise as viewed from the right side surface), it is indicated by the arrow F ′. The wire 201 is wound counterclockwise (W direction shown in the figure) around the rod 202 rotating in the arrow N direction (clockwise as viewed from the right side) as shown in FIG. If it is, the direction of the left hand in the figure indicated by the arrow F and the rotation of the wire bar 203 causes the coating liquid 211 to be agitated, that is, the pumping by the pumping action of the wire bar 203 as described above. It was confirmed that an effect was obtained.

  Further, the movement of the coating liquid 211 described above causes the coating liquid 211 by the pumping action from the coating liquid supply hole 210 and the pumping action by the wire bar 203 when the pumping action of the wire bar 203 is applied in the direction opposite to the liquid supply direction. It was also confirmed that the front and rear disturbances became unstable due to the collision and the traveling direction coincided with the liquid supply direction or reverse direction, which caused stagnation.

  Furthermore, the movement of the coating liquid 211 described above moves greatly even when the viscosity of the coating liquid 211 is about 5 to 10 cps, and the coating liquid 211 is more noticeable as the solvent type is more than a simple aqueous solution. It was found that the movement due to the thrust force was extremely small.

  It has also been investigated that the coating liquid supply hole 210 is preferably provided in the vicinity of the bottom wall as much as possible, since the coating liquid 211 is located near the bottom wall of the liquid supply side manifold 206.

  Next, when the coating liquid 211 was applied to a web 212 made of PET (polyethylene terephthalate) having a thickness of 100 μm continuously running at a speed of 20 m / min using the coating head 200, the coating liquid 211 was applied depending on the winding direction of the wire 201. There was a clear distinction between the case where there was no unevenness and the case where it appeared somewhat. Therefore, the wire bar 203 is arranged by aligning the winding direction of the wire 201 with the direction in which the coating liquid 211 is sent from one end side to the other end side in the width direction of the liquid supply side manifold 206 by the thrust force generated by the rotation of the wire bar 203. When the coating was performed in the same manner as described above, it was confirmed that there was no coating unevenness in the coating film.

  The above is an experiment on narrow width coating with an open type wire bar coating head 200 of about 400 mm. From the knowledge of the pumping action of the wire bar 203 obtained by the experiment and this effect, the wire bar coating head 200 is used. Of course, it is a closed type, and even if the application width is 2000 to 3000 mm, it is confirmed that the desired application can be expected, and an experimental apparatus as shown in the front sectional view in FIG. A temporary manifold channel was prepared assuming a type of wire bar coating head 300, and the following experiment was performed using this.

This temporary channel has a cross-sectional area of 6 cm ² and a length of 1500 mm, and a wire bar 303 having a diameter of 10 mm can be installed inside. One end of the wire bar 303 is rotatably supported by the bearing in a closed state on the other end side (counter liquid supply side) of the temporary flow path, and the other end is outside from the other end side (that is, liquid supply side) of the temporary flow path. , And is rotatably supported by a bearing, and its extended end is connected to a motor M that rotates in the direction of arrow N. The wire bar 303 is arranged so that the acting direction F of the thrust force works from the other end side (liquid supply side) to the one end side (counter liquid supply side) when the motor M rotates in the arrow N direction. ing.

  In the temporary flow path, as shown in the drawing, a fine pressure gauge 3 (B3), a distance L2 are placed at a distance L1 from the outlet of the liquid supply hole 310, a fine pressure gauge 2 (B2), and a distance L3 is further placed. The micro pressure gauge 1 (B1) is installed.

  In this apparatus, the distance from the outlet of the liquid supply hole 310 to the position of the micro pressure gauge B3 (ie, distance L1) is 100 mm, and the distance from the outlet of the liquid supply hole 310 to the position of the micro pressure gauge B2 (ie, distance L1 + distance L2) is 650 mm. From the B2 position to the micro pressure gauge B1 position (ie, the distance L3) is set to 650 mm, and two types of wires 301 having a diameter of 1600 mm and a diameter of 10 mm are wound around a rod 302 having a diameter of 200 μm and 75 μm, respectively, with a winding width of 1480 mm. Two types of wire bars 303A and 303B were produced by turning the test piece, and the following experiment was performed using an aqueous solution 311W as a solution.

  First, using a wire bar 303A formed by winding a wire 301 having a diameter of 200 μm around a rod 302 having a diameter of 10 mm, an aqueous solution 311W having a static pressure of 400 mmAq is supplied from the liquid supply side into the liquid supply side manifold 306 from the liquid supply hole 310. As a result, the pressure inside the liquid supply side manifold 306 is 350 mmAq at the L1 point (installation position of the micro pressure gauge B3), 400 mmAq at the L2 point (installation position of the micro pressure gauge B2), and the L3 point (installation position of the micro pressure gauge B1). It became 380 mmAq. Considering this result, it was found that there was a liquid leak from the extending portion of the wire bar 303A at the L1 point, and that the static pressure was lowered due to this, and at the L3 point, the static pressure was reduced due to the resistance to the wall surface in the manifold. It was estimated that the pressure was low. From this, it was estimated that when the manifold has a narrow flow path of 2000 mm to 3000 mm, the static pressure is further lowered at a point away from the liquid supply hole 310.

  Therefore, in order to see the pumping effect of the wire bar 303A in this state, when the wire bar 303A was rotated at 100 rpm, the static pressure increased to 460 mmAq at about L2 and L3 points in about 30 seconds, but only up to 400 mmAq at the L1 point. The liquid could not be covered. Therefore, since there is no problem at the L2 point, the L1 point is separated from the liquid supply hole 310 and the distance L1 is set to 300 mm. As a result, as shown in Table 1, the micro pressure gauges B1, B2, and B3 are installed. The static pressure was 460 mmAq at all points. From this, even if there is some liquid leakage from the extension part of the wire bar 303A, by slightly shifting the liquid supply position from the application point, in other words, by separating the extension part of the wire bar 303A from the application part, It has been demonstrated that a uniform solution can be distributed over the entire area.

  Moreover, when a wire bar 303B formed by winding a wire 301 having a diameter of 75 μm around a rod 302 having a diameter of 10 mm was used, an experiment similar to the above was performed, and the results shown in Table 1 were obtained.

表１から明らかなように、このワイヤバー塗布ヘッド３００の結果から、前述したポンピング効果により、２０００〜３０００ｍｍ幅の幅方向における静圧を、位置とは無関係に、常に一定とすることができること、換言すれば、長さが２０００ｍｍないし３０００ｍｍの長大塗布ヘッドであっても全幅に亘り溶液を均一に供給できること、また、ワイヤ３０１の径が大きくなるとポンピング効果が増大され、送液量が変えられること、また、クローズド系の中では見かけ上の静圧が高められることが実証された。

As is apparent from Table 1, from the result of the wire bar coating head 300, the static pressure in the width direction of 2000 to 3000 mm width can be always kept constant regardless of the position by the pumping effect described above. Then, even with a long coating head having a length of 2000 mm to 3000 mm, the solution can be uniformly supplied over the entire width, and when the diameter of the wire 301 is increased, the pumping effect is increased, and the liquid feeding amount can be changed. It was also demonstrated that the apparent static pressure can be increased in a closed system.

  In addition, as long as the rotational speed was changed within a range of ± 5%, the static pressure was hardly changed, but the diameter of the wire 301 was kept at 200 μm and the rotational speed was lowered from 100 rpm to 50 rpm, which is half. As a result, it was also confirmed that the static pressure only increased to about 420 mmAq. From this, it was found that the movement of the solution changes greatly as the rotational speed of the wire bar 303 is increased.

  Further, even when the wire bar 303 continued to rotate (in a state where no coating was applied), it was found that the pressure did not rise above a certain level at the same rotational speed, and it was found that only the dispersion effect could be sustained. This effect is a characteristic effect of the present invention along with the pumping effect.

  The above is a case where the solution is an aqueous solution 311W. However, even if this solution is a solvent-based coating solution similar to that in Example 1, it is also clarified that there is no change in the above-described effects. ing.

  In view of the above-described pumping effect, the present inventor has devised the following wire bar coating head 400 that can apply the uniform coating liquid 311 evenly to the wire bar 303 by improving the wire bar coating head 300.

  That is, in this wire bar coating head 400, on the front wall in the width direction of the liquid supply side manifold 306 in the wire bar coating head 300, as shown in a plan sectional view in FIG. The three coating liquid supply holes 410A, 410B, 410C having substantially the same configuration as the coating liquid supply hole 410 are disposed at substantially equal intervals, with the supply hole directed to the left). Is supplied to the inside from a coating liquid supply hole 410 provided on one side wall in the width direction of the liquid supply side manifold 306, and the coating liquid 411 is also supplied from these three coating liquid supply holes 410A, 410B, 410C. It is configured as follows.

  Using this wire bar coating head 400 configured as described above, the behavior of the coating liquid 411 was confirmed by operating the apparatus in the same manner as described above. As a result, the coating liquid 411 supplied to the inside was more smoothly fed from one end side in the width direction. A phenomenon that the coating liquid 411 stays in the liquid supply side manifold 406 was not seen at all.

  Incidentally, the direction of the three coating liquid supply holes 410A, 410B, 410C is set in the direction opposite to the thrust force acting direction F (from left to right in FIG. 7), and the coating liquid 411 is placed inside the liquid supply side manifold 406. When supplied, a phenomenon that the coating liquid 411 stagnate on the bottom wall side was observed.

  In the present embodiment, the three coating liquid supply holes 410A, 410B, and 410C are provided. However, the number of the coating liquid supply holes is not particularly limited, and it is clear by the present inventor that even one is effective. Has been. Further, the direction of each of the coating liquid supply holes 410A, 410B, and 410C does not need to be completely coincident with the direction of the arrow F to which the coating liquid 411 is sent, and the purpose can be sufficiently achieved even in a direction that is approximately approximate. .

  Further, as a result of intensive studies in view of the above-described pumping effect, the present inventor has devised the following wire bar coating head 500 according to an improved type different from the wire bar coating head 400.

  That is, as shown in the front sectional view of FIG. 8, this wire bar coating head 500 is a coating wire bar (first wire) having a length of 1500 mm formed by closely winding a wire 501 having a diameter of 75 μm around a rod 502 having a diameter of 8 mm. The wire bar 503 is rotated by the motor M in the direction of arrow N at a rotational speed of 800 rpm, and the coating liquid 511 is introduced into the interior from a coating liquid supply hole (not shown) provided in one side wall in the width direction of the liquid supply side manifold 506. The coating liquid 511 is configured to be pulled upward as the wire bar 503 rotates, while the liquid supply side manifold 506 has substantially the same configuration as the coating wire bar 503. The second wire bar 523 is rotatably supported by a backup 524.

  The wire bar 523 has a length of 1500 mm formed by winding a wire 501 having a diameter of 100 μm around a rod 502 having a diameter of 8 mm, and is set on an upper portion of a backup 524 erected on the base 504. Although not shown, both ends of the shaft portion are rotatably supported by bearings, and the extending shaft end is connected to a motor capable of speed control by a drive system different from the coating wire bar 503. In order to optimize the pumping effect in the liquid supply side manifold 506, the application is controlled so as to rotate in conjunction with the wire bar 503 for coating.

  Using this wire bar coating head 500 configured as described above, an experiment was performed in which the coating liquid 511 was applied to the continuously running web 512 in the same manner as in the above example. The coating liquid 511 is positively moved in the liquid feeding direction (arrow F direction) and stirred by the wire bar 503 and the second wire bar 523, so that the coating liquid 511 can be applied even if long-time coating is performed. However, it stayed and condensed inside the liquid supply side manifold 506 and no sticking was generated, and the filler did not become large particles, and a high-quality coating film free from unevenness and scratches was obtained.

  In the fifth embodiment, the second wire bar 523 is provided in the liquid supply side manifold 506. However, the second wire bar 523 may be provided in the liquid discharge side manifold 507 like the next wire bar application head 600.

  That is, as shown in a front sectional view in FIG. 9, the wire bar coating head 600 is erected at the center of the base 604 in the running direction of the web 612 and supports the coating wire bar 603 rotatably. In a coating head comprising a liquid supply side coater block 608 and a liquid discharge side coater block 609 that form a liquid supply side manifold 606 and a liquid discharge side manifold 607 on the upstream side and downstream side of the backup 605, respectively, The second wire bar 633 having substantially the same structure as the wire bar for coating (first wire bar) 603 is rotatably supported by the backup 634 in the space above the same as in the fifth embodiment. It is made up of.

  In the wire bar coating head 600 configured as described above, the surplus coating liquid 611 after coating is returned and mixed with the coating liquid 611 inside the drain side manifold 607. In reality, the return liquid is more likely to agglomerate because the solvent is evaporated than the stock solution. At this time, in the present wire bar coating head 600, the coating liquid 611 is homogenized by the pumping effect and the dispersion effect of the second wire bar 633 provided inside the drain side manifold 607, thereby generating noro and aggregation of the filler. Larger particles can be prevented, and damage to the coating wire bar 603 can be more reliably prevented.

  At the same time, the new liquid is also sent to the drain side manifold 607, but the mixture of the new liquid and the excess liquid by the rotation of the coating wire bar 603 is partially supplied to the supply side manifold 606 as the coating liquid 611. Moving. Therefore, the inside of the drain side manifold 607 tends to be deficient in the coating liquid 611, and apparently the pressure inside the supply side manifold 606 is low. In a thin layer coating with a wet film thickness of 5 μm or less, most of the excess liquid is drawn into the drain side manifold 607, and at this time, an air layer adhering to the surface layer portion of the excess coating liquid 611 easily flows. Become.

  However, a wire bar 603 for coating is provided, and this is properly rotated by another speed control motor, so that the shortage of the coating liquid 611 is supplemented by this pumping effect, and the new liquid and surplus liquid are stirred. It is possible to expect another effect that the air in the surplus liquid surface layer portion can be prevented from flowing in by uniformizing and supplying it to the supply side as a harmless state and simultaneously pushing out part through the gap t described above. It has been confirmed.

  By the way, in the wire bar coating method, particularly in the state of coating a thin layer having a wet film thickness of 5 μm or less, the coating liquid foams and foams adhere to the contact surface between the wire bar and the continuously running web. As described above, there is a specific problem that the quality of the film is impaired. Considering this point with respect to the wire bar coating head according to the above-described embodiment, although the degree of generation of bubbles is reduced by the pumping action and its effect, it is not the case that there is no concern at all.

  As described above, the cause of such bubbles is that the application liquid inside the drain side manifold tends to be insufficient, and the pressure inside the drain side manifold is always lower than the pressure inside the liquid supply side manifold. Since the present inventor is considered to be in the state, the present inventor supplies the coating liquid in order to always make the pressure inside the drain side manifold higher than the pressure inside the liquid side manifold. The generation of such bubbles can be further prevented by increasing the amount so that a constant amount of coating liquid is always pushed out from the drain side manifold, and as shown in the front sectional view of FIG. The wire bar coating head 700 was devised.

  This wire bar coating head 700 is aimed at the synergistic effect of the wire bar coating head 500 and the wire bar coating head 600 described above. As shown in the figure, a second wire bar 723 is provided inside the liquid supply side manifold 706 by a backup 724. In addition, the third wire bar 733 is rotatably supported by the backup 734 inside the drain side manifold 707. Here, both the second wire bar 723 and the third wire bar 733 are configured so that the uniform coating liquid 711 extends over the entire length of the wire bar coating head 700 by utilizing the pumping effect.

  Further, the third wire bar 733 in the drain side manifold 707 is set so that the amount of liquid fed is somewhat larger than that of the second wire bar 723 in the liquid side manifold 706 so that the drain side manifold can be applied even when a thin layer is applied. The coating liquid 711 in 707 is pushed to the outside to some extent, thereby preventing the air layer from flowing into the surface layer of the surplus liquid and preventing bubbles from being generated during coating. Therefore, when the second wire bar 723 has a wire diameter of 100 μm and the third wire bar 733 has a wire diameter of 150 μm and is rotated at 100 rpm, the drain wire side manifold 707 is closed in a closed state. A pumping effect is contemplated such that the pressure is about 30 mmAq higher than the pressure in the supply side manifold 706.

  In this situation, a wire bar (first wire bar) 703 for coating was used in which a wire having a diameter of 75 μm was closely wound with a wet film thickness of about 5 μm, and the coating speed was set to 20 m / min. As a result of performing the experiment by rotating the second wire bar 723 and the third wire bar 733 at 100 rpm, when the second wire bar 723 and the third wire bar 733 are rotated, almost no bubbles are seen in the coated sample. However, when the third wire bar 733 was stopped, considerable foam failure was observed in the coated sample. From this result, it has been proved that the foaming problem is largely eliminated by preventing the coating liquid 711 from being drawn into the drain side manifold 707 together with the air layer of the surplus liquid surface layer during thin layer coating.

  As described above, the content of the present invention has been described based on Examples 1 to 6 in which the coating bar for applying the coating solution to the continuously running web is a wire bar. It is not limited to such a wire bar, For example, a rolling bar and the D-bar which is the typical example (brand name of OSG System Products Co., Ltd.) can be applied. These bar members are formed by forming a spiral groove on the outer periphery of the rod, and have the same configuration as the above-described wire bar formed by closely winding a wire around the rod in a spiral manner, and substantially the same as this wire bar. There is an effect. Therefore, it goes without saying that these bar members can substitute for the second and third wire bars used for the purpose of moving and stirring the coating solution, that is, with the intention of the pumping effect and the dispersion effect. As a member that can substitute for such second and third wire bars, a screw member formed by spirally engraving a screw on a shaft (rod) or a similar member can be applied. .

100, 200, 300, 400, 500, 600, 700 Wire bar coating head 101, 201, 301, 401 Wire 102, 202, 302, 402 Rod 103, 203, 303, 403, 503, 603, 703 Wire bar 104, 204, 504, 604, 704, Base 105, 205, 505, 605, 705 Backup 106, 206, 306, 406, 506, 606, 706 Supply side manifold 107, 207, 307, 407, 507, 607, 707 Drain Side manifold 108, 208, 508, 608, 708 Supply side coater block 109, 209, 509, 609, 709 Drain side coater block 110, 410 Application liquid supply holes 111, 211, 411, 511, 611, 711 Application liquid 112, 212, 11,829 web 311W aqueous 523,623,633,733 (coating solution) (second and third) wire bar M motor P stagnation

Claims (9)

  Grooves are formed in the surface of the rod in a spiral shape, a coating bar for applying the coating liquid to the continuously running web, a backup standing on the base and rotatably supporting the bar, and the backup Bar coating comprising a liquid supply side coater block and a liquid discharge side coater block which are provided on the upstream and downstream bases and form a liquid supply side manifold and a liquid discharge side manifold respectively with the backup. In the head, there is provided a coating liquid supply hole for supplying coating liquid to the inside of the liquid supply side manifold and the drainage side manifold on one end side wall in the width direction of the liquid supply side manifold, and thrust generated by rotation of the bar The bar is arranged by aligning the groove forming direction with the direction in which the coating liquid in the liquid supply side manifold is fed from one end side to the other end side in the width direction by force. Bar coating head, characterized by comprising.   At least one second coating liquid supply hole having substantially the same configuration as the coating liquid supply hole is provided on the liquid supply side front wall of the liquid supply side manifold in the direction of feeding the coating liquid. The bar coating head according to claim 1, wherein the bar coating head is provided.   The bar coating head according to claim 1, wherein the coating liquid supply hole is provided near a bottom wall of the liquid supply side manifold.   The second bar having substantially the same configuration as the coating bar is rotatably provided inside the liquid supply side manifold or the drain side manifold. 4. The bar coating head according to any one of items 3 to 3.   A second bar and a third bar each having substantially the same configuration as the coating bar are rotatably provided inside the liquid supply side manifold and the drain side manifold, and The bar coating head according to any one of claims 1 to 3, wherein the pressure inside the drain side manifold is set higher than the pressure inside the liquid side manifold.   6. The bar coating head according to claim 4, wherein the second bar and / or the third bar are rotated in conjunction with the coating bar during coating.   7. The coating bar according to claim 1, wherein the coating bar is one of a wire bar, a rolling bar, and a D-bar (product name of OSG System Products Co., Ltd.). Bar coating head.   8. The bar coating head according to claim 1, wherein the coating head is a closed type, and the coating liquid is a solvent type coating liquid.   A bar coating apparatus comprising the bar coating head according to any one of claims 1 to 8, wherein the coating liquid is applied to the continuously running web by the bar coating head.

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