JP2006281196A - Application apparatus, application method and method for manufacturing web having coating film - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an application apparatus capable of preventing supply stripes due to supply irregularity which is liable to occur upon coating liquid supply and bubble stripes due to bubble entrainment, and capable of reducing unevenness of thickness, and to provide an application method and a method for manufacturing web having coating film which uses the application apparatus. <P>SOLUTION: The application apparatus which applies coating liquid on the upper surface of a running web with an application bar comprises a coating liquid supply means which directly supplies coating liquid to a paddle of liquid formed on a contact part between the application bar and the web, wherein the coating liquid supply means has a smooth part on which the coating liquid can flow in such a state that the upper part is open. In the application method and the method for manufacturing web having coating film, the application apparatus is used. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a coating apparatus, a coating method, and a coating film forming method for coating a coating solution on a top surface of a web such as a running film with a coating bar, and in particular, coating defects (feeding streaks, foam streaks). The present invention relates to a coating apparatus, a coating method, and a coating film-forming web manufacturing method that can suitably prevent generation and reduce thickness unevenness.

For example, as shown in FIG. 7, four rollers 104 (widths) provided on the downstream side of the die 102 are supplied with a coating solution 103 from a die 102 serving as a coating solution supply unit on the upper surface of a running web 101. The coating thickness of the coating liquid supplied to the upper surface of the web 101 is measured or smoothed by a metalling bar 105 as a coating bar that is rotatably supported by a total of four pairs at both ends in the direction. Such a coating device is known.

However, in such a conventional apparatus, there may be a coating defect called a supply line 106 or a bubble line 107 as shown in FIG. Such coating defects include irregularities in the supply of the coating liquid 103 from the die 102, and air biting between the supplied coating liquid 103 and the web 101 (air biting position A) as shown in FIG. It is believed that this occurs because the metering bar 105 is not properly discharged.

To solve the above problems, Patent Document 1 discloses a technique using a relatively low viscosity coating liquid. However, the coating liquid is supplied onto the coating bar by a die installed in the vicinity of the coating bar. A technique has been proposed in which a liquid puddle is formed and applied at the contact portion between the work bar and the web.
However, according to the knowledge of the present inventor, if the proposed technique is applied to a case where a high-viscosity coating liquid having a viscosity of 0.1 Pa · s (100 cp) or more is used, the supply streak still remains. May occur. Further, when the viscosity of the coating liquid 103 is 0.1 Pa · s (100 cp) or higher, as shown in FIG. 10, the coating liquid 103 is caught between the coating bar 103 and the coating bar 105 (air biting position B). Air flows into the liquid pool 108 while being trapped in the coating liquid, and as a result, bubbles are entangled in the coating bar 105, and bubble streaks are likely to occur. Further, in the supply of the coating liquid by the die or the nozzle, if there is supply unevenness in the web width direction, the supply unevenness cannot be completely flattened by the coating bar, and uneven coating thickness of the coating liquid occurs. In order to prevent this, as means for increasing the discharge uniformity of the coating liquid in the width direction of the web, means for reducing the slit gap of the die can be mentioned. However, if the slit gap is narrow, cleaning of the lip portion becomes difficult. When the die width (width in the width direction of the web) is wide, if the supply pressure of the coating liquid is high, the lip gap is opened by the internal pressure, and a uniform gap cannot be maintained in the width direction.

By the way, there is a slide coater disclosed in Non-Patent Document 1 as a technique that seems to be similar to the preferred embodiment of the present invention.
Japanese Patent No. 2805177 Yoshinobu Katagiri, Theory and Explanation of Die Coater, Coating -Learning the Future from the Past and Present of Hardware Technology-, Japan, Processing Technology Research Group, March 25, 2002, p399

  Therefore, the object of the present invention is to solve the above-mentioned problems, to prevent supply streaks that are likely to occur during the supply of coating liquid, and to prevent generation of foam streaks due to bubble entrapment, and to reduce thickness unevenness caused by supply unevenness. It is an object of the present invention to provide a coating apparatus and a coating method capable of performing the above.

In order to solve the above-described problems, a coating apparatus according to the present invention is a coating apparatus that applies a coating liquid to an upper surface of a running web with a coating bar, and includes a contact portion between the coating bar and the web. It has a coating liquid supply means for directly supplying a coating liquid to a liquid pool formation site in the vicinity of the upstream side.
In the present invention, the “liquid pool” means a pool of coating liquid formed around a region sandwiched between a web and a coating bar on the upstream side of the coating bar from a contact portion between the coating bar and the web during coating. Say. Needless to say, the coating liquid remaining thinly on the surface of the coating bar or on the surface of the web during continuous application is not a liquid pool here. This is because these thin coating liquids move following the movement of the coating bar and the web surface as they are, and the coating liquid is not accumulated.
The vicinity of the upstream side of the coating bar where the puddle is to be formed is referred to as a puddle formation site.
In the present invention, “directly supplying the coating liquid to the puddle formation site” means that the coating liquid discharged from the nozzle or die is supplied to the puddle formation site so that the coating liquid contacts the web and the coating bar. Direct contact with the puddle before starting.
Further, in the present invention, the “coating bar” is conventionally used for coating a coating liquid such as a rod, a wire bar obtained by winding a wire around a rod, and a bar with a groove formed by cutting a groove in a rod. Says the bar. The coating bar is normally rotatable in the same direction as the web traveling direction, but may be rotated in the direction opposite to the web traveling direction.

  According to another preferred embodiment of the present invention, there is provided a coating apparatus for applying a coating liquid to the upper surface of a running web by a coating bar, the coating liquid being upstream of the position of the coating bar. There is provided a coating apparatus having a coating liquid supplying means for supplying the coating liquid to the upper surface of the web at a position, and the coating liquid supplying means has a smooth portion where the coating liquid flows down with the upper part opened. The

In the present invention, the “open state” means a state in which a substance other than gas is not in contact with the vertical upper surface of the coating liquid when the coating liquid flows down on the object.
In the present invention, the “smooth part” is a surface portion that defines the lower surface of the flow path through which the coating liquid flows in the state where the upper part is opened in the coating liquid supply means when supplying the coating liquid, In which the surface roughness (maximum height Ry) of the portion through which the gas flows is 100 μm or less and the flatness is 0.2 mm or less. In the examples described later, the surface roughness is measured using an ultra-deep surface shape measuring microscope (VK8500 manufactured by Keyence Corporation), and the angle α shown in FIG. Measurement was performed from a direction perpendicular to the various parts in accordance with the standard of JISB0633. In addition, flatness is measured using a high-accuracy three-dimensional shape measurement system (XYZAX GC600D-34, manufactured by Tokyo Seimitsu Co., Ltd.) in the same manner as the measurement of surface roughness, in accordance with the standard of JISB0621. Was done.
Moreover, according to the preferable form of this invention, the inclination | tilt angle with respect to the horizontal direction of the said smooth site | part is 10-60 degrees, and the distance which a coating liquid flows in the state which the upper part was open | released is 10 mm or more and 200 mm or less. An application device is provided.
In the present invention, the “inclination angle with respect to the horizontal direction” refers to an angle formed by a horizontal line and a surface of a smooth portion, and is indicated by an inclination angle θ in FIG. When the inclination angle θ is less than 10 degrees, it may leak from both ends of the smooth portion when the coating liquid flows down, dripping onto the web, and causing supply stripes. Further, when the inclination angle θ exceeds 60 degrees, the action of flattening the coating liquid may be insufficient in a smooth region.
According to a preferred embodiment of the present invention, the coating liquid supply means is positioned so as to directly supply the coating liquid to a liquid pool formation site in the vicinity of the upstream side of the contact portion between the coating bar and the web. An application device is provided. Moreover, according to the preferable form of this invention, the application | coating apparatus in which the front end by the side of the said application | coating bar of the said smooth part has the shape of a downward concave shape where both ends extend below rather than the center part in the width direction of the said web. Is provided. The shape of the outer surface of the liquid puddle formed upstream of the coating bar swells outward at the center in the width direction of the web, and then swells toward both ends from there. FIG. 12 shows this state. FIG. 12 shows an embodiment of the coating apparatus of the present invention. In FIG. 12, a die 110 as a coating liquid supply means has a smooth portion 111 at the tip, and a part of the tip of the smooth portion 111 is positioned in contact with the liquid pool 108. In this state, the coating liquid is supplied to the liquid pool 108, and the coating liquid is measured or smoothed by, for example, a metering bar 105 as a coating bar supported by two rollers 104 provided on the left and right sides. As shown in FIG. 12, the shape of the outer surface of the liquid pool 108 swells outward at the center in the width direction of the web 101, and from there toward both ends, The bulge is often small. When the tip of the smooth part 111 is supplied in contact with the liquid pool, a streak 109 is generated from both ends 113 of the part of the smooth part 111 that is in contact with the liquid pool 108 as shown in FIG. The product width that can be reduced. This problem can be solved by forming the coating apparatus 11 in the form shown in FIG. That is, in FIG. 13, the shape of the tip of the smooth portion 111 is substantially aligned with the outer shape of the liquid pool 108, particularly at both ends, as shown in FIG. The most part of the full width of the distal end of the portion 111 is brought into contact with the liquid pool 108. According to this form, the generation | occurrence | production position of the stripe 109 can be moved to the application | coating end part side, and the increase in the width | variety of the web in which the coating film which can be used as a product was formed can be aimed at.

In the present invention, the downward concave shape means a shape in which the end of a smooth portion has both ends extending downward from the center in the width direction of the web. The shape preferably corresponds to the shape of the outer surface of the liquid puddle 108, but it may not be a circular arc and may be formed by a series of at least two straight lines.

Moreover, it is preferable that the said coating liquid supply means consists of a means to supply a coating liquid continuously. That is, the coating liquid supplied from the coating liquid supply means is supplied in a continuously connected state without interruption. As will be described later, since supply streaks are caused when the liquid is supplied so as to droop over the liquid pool, it is preferable to continuously supply the coating liquid in this way.
Further, according to a preferred embodiment of the present invention, there is provided a coating apparatus, wherein the coating liquid supply means comprises means for setting the distance until the coating liquid supplied from the coating liquid supply means falls within a liquid pool within 80 mm. Is done. If the coating solution leaves the end of the coating solution supply means, falls into the puddle and reaches the puddle, and the distance to reach the puddle is too large, the puddle becomes unstable due to the pressure fluctuation of the coating solution that occurs at the time of dropping. Because there are cases. If the liquid pool becomes unstable, a coating defect is likely to occur due to this.
In the present invention, the “distance until the coating liquid falls into the liquid pool” means the vertical distance that the coating liquid away from the coating liquid supply means moves to contact the liquid pool while falling in the gas This is shown in FIG. 1 and FIG. 1 and 11 show a coating apparatus and a coating method according to an embodiment of the present invention. In FIG. 1, a coating device 10 includes a device for supplying a coating liquid 4 from a die 3 as a coating liquid supply means to a liquid pool 6 on the upper surface of a running web 2 by a coating bar 1.
In FIG. 11, the coating apparatus 11 is such that the coating liquid supply means has a smooth portion 20, and other configurations are the same as those in FIG. 1. The “distance until the coating liquid falls into the liquid pool” is a portion H shown in each figure. In FIG. 1, the vertical direction from the lower end of the die 3 as the coating liquid supply means to the upper end of the liquid pool is shown. In FIG. 11, the distance in the vertical direction from the lower end of the smooth portion 20 serving as the coating liquid supply means to the upper end of the liquid pool is shown.
In addition, FIG. 17 is explanatory drawing at the time of inserting a coating liquid supply means in a liquid pool. The coating liquid supply means is composed of a die 110 and a smooth part 111 coupled to the tip thereof, and the coating liquid 4 discharged from the die 110 and flowing down the upper surface of the smooth part 111 is directly supplied to the liquid pool 108, The coating liquid of the pool 108 is applied to the upper surface of the running web 101 by a coating bar (metal ring bar) 105 that is rotatably supported by a roller 104. The tip of the smooth portion 111 of the coating liquid supply means is inserted into the liquid pool 108. In the form in which the tip of the coating liquid supply means is inserted into the liquid pool, the “distance until the coating liquid falls into the liquid pool” is defined as 0 (zero).

  Moreover, it is preferable that the said coating liquid supply means consists of a means which can move independently of the said coating bar. By making it independently movable, for example, when the coating liquid being supplied is shaken by the static electricity of the web, it is possible to appropriately adjust the relative position of the coating liquid supply means with respect to the coating bar. Further, the coating liquid supply means can be quickly retracted to an appropriate position at the end of application.

Moreover, it is preferable that the said coating liquid supply means can be moved by the said moving means in the range of 0.1-500 mm with respect to the said coating bar during application | coating of a coating liquid. Here, the “distance between the coating liquid supply means and the coating bar” refers to the shortest distance from the surface of the coating bar to the coating liquid supply means, and is a portion L shown in FIGS. 1 and 11. In addition, when the smooth part has a downward concave shape in which both ends extend downward from the center part in the web width direction, the “distance between the coating liquid supply means and the coating bar” refers to the smooth part. The shortest distance to the surface of the coating bar at each position in the width direction of the web.
By making it movable in such a range, it is possible to easily adjust the relative position of the coating liquid supply means with respect to the above-described coating bar and to retract the coating liquid supply means at the end of coating.

  Moreover, it is preferable that this coating apparatus has a liquid receptacle which can receive the coating liquid from the said coating liquid supply means. With such a liquid receiver, it is possible to easily prevent the coating liquid from dripping onto the web or the like from the coating liquid supply means, in particular, after the end of coating or before the start of coating.

The coating method according to the present invention is a coating method in which a coating liquid having a viscosity of 0.1 to 3.0 Pa · s (100 to 3000 cp) is applied to the upper surface of a running web by a coating bar. The coating liquid is directly supplied to a liquid pool formed on the upstream side of the contact portion between the work bar and the web. That is, it is a method in which the coating liquid is directly supplied to the pool before contacting the coating bar or web.
In the present invention, the viscosity was measured according to the standard of JISZ8803 using a rheometer (RC20 manufactured by Rheotech).
In the present invention, “directly supplying the coating liquid to the liquid pool” means that the coating liquid discharged from the nozzle or die is brought into direct contact with the liquid pool before the coating liquid contacts the web and the coating bar. . Moreover, it is preferable to supply the coating liquid continuously without interruption.

  Moreover, it is preferable that the distance until the supplied coating liquid falls into the liquid pool is within 80 mm.

  Moreover, the web in which the coating liquid is applied and the coating film is formed on the surface can be stretched and dried after the application. These stretching and drying are performed by stretching after stretching, stretching after drying, or simultaneously stretching and drying.

  Furthermore, the present invention provides a coating film formation in which a polymer is extruded by an extruder, the polymer is formed into a sheet shape to form a web, and the coating solution is applied onto the web by using the coating method. A web manufacturing method is also provided.

  According to the coating apparatus and the coating method according to the present invention, the above-described coating defects caused by the conventional coating liquid supply do not occur. Moreover, coating thickness unevenness can be reduced.

  In addition, if the position of the coating liquid supply means can be adjusted independently with respect to the coating bar, the coating liquid can be accurately supplied to the target position regardless of the electrostatic charge state of the web. . In addition, even if the size of the liquid pool changes, it becomes possible to cope with various varieties and application widths. Furthermore, when the application is finished, it can be finished quickly. For example, by separating the coating liquid supply means from the web and then separating the coating bar, even if the coating liquid drops from the coating liquid supply means, the coating bar is smoothed. It is possible to prevent contamination of the device due to insufficient drying.

Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. In FIG. 1, a coating apparatus 10 of the present invention travels upstream of the coating bar 1, a web transport device (not shown) that travels the web 2 below the coating bar 1, and the coating bar 1. The coating liquid supply means (die 3) is provided so that the coating liquid is directly supplied to the liquid pool 6 formed in contact with the web 2 and the coating bar 1 to be applied.

In the coating apparatus 10, the coating liquid 4 is directly supplied from the die 3 as a coating liquid supply unit to the liquid pool 6. The die 3 can be moved between the coating liquid supply indicated by the solid line and the retracted position indicated by the broken line by the moving mechanism 5. A liquid pool 6 is formed immediately upstream of the contact portion between the coating bar 1 and the web 2, but the coating liquid 4 discharged from the die 3 is not in contact with the coating bar 1 or the web 2. The liquid pool 6 is directly supplied. The coating liquid 4 is supplied into the die 3 through a pump 7 and a filter 8 from a suitable coating liquid tank (not shown). Reference numeral 9 denotes a liquid receiver provided below the retracted position of the die 3 for receiving the coating liquid dripping from the die 3.
FIG. 14 is an arrow view from the Y direction of FIG. 15 and 16 are enlarged views of a portion C surrounded by a dotted line in FIG. Examples of the coating bar include a rod, a wire bar in which a wire is wound around the rod, and a bar with a groove formed by cutting a groove in the rod. The coating bar 1 shown in FIG. belongs to. As shown in FIG. 14, the coating bar 1 has a groove formed on the surface thereof by a wire wound around the surface of the rod. The coating bar 1 is brought into contact with the web 2 to apply the coating liquid onto the upper surface of the web 2. As shown in FIG. 15 or FIG. 16, a coating liquid is present at the contact portion between the coating bar 1 and the web 2, and a gap (coating bar surface) generated between the coating bar 1 and the web 2. The amount of coating liquid according to the size of the groove portion and the gap portion between the coating bar and the web is applied to the web 2.
FIG. 2 shows a side view of an example in which the coating bar 1 is rotated forward in the running direction of the web 2. As described above, the coating liquid 4 discharged from the die 3 is placed on the pool 6. By being supplied directly, supply stripes are less likely to occur. Further, by supplying the liquid directly onto the liquid pool 6, there is no room for air to be caught in this portion, and the possibility of generation of bubble streaks due to the air biting is eliminated.

  As the coating liquid supply means, a die, nozzle, spray, or the like that can discharge the coating liquid without interruption is preferable. Further, the supply of the coating liquid to the liquid pool 6 may be performed directly on the surface of the liquid pool, or the nozzle or the discharge port of the die may be inserted into the liquid pool and directly supplied to the inside.

In addition, if there is a change in the discharge of the pump, the size of the liquid puddle changes and the application width changes, so it is preferable to use a metering pump such as a gear pump, a mono pump, or a diaphragm pump as the pump 7. In order to stabilize the liquid pool, it is preferable to use a pump having a pulsation rate of -3.5% to + 3.5%. Here, the pulsation rate is defined as follows.
Pulsation rate = [(instant maximum discharge amount−instant minimum discharge amount) / average discharge amount] × (100/2)
The pulsation rate is measured with a mass flow meter (for example, model 63FS08-NEW00A30B1A manufactured by Endless Hauser, Inc.) at a measurement cycle of 0.15 s.

  In the coating apparatus 10, when the coating liquid 4 is interrupted and supplied to the liquid pool 6 in the form of droplets as shown in FIG. 3, for example, the fluid pressure fluctuates due to the discontinuous dropping of the droplets. It is preferable that the coating liquid is continuously supplied to the liquid pool 6 without interruption because there is a possibility that a coating defect may occur due to this.

  When the running web 2 is charged with static electricity, for example, as shown in FIG. 4A, the coating liquid 4 discharged from the die 3 is pulled by static electricity and supplied to the liquid pool 6. There is a risk of contacting the web 2 before. Even in such a case, it is preferable to adjust the position of the die 3 in order to achieve direct supply to the liquid pool 6 in the present invention. This position adjustment is achieved by the moving mechanism 5 in this embodiment. By appropriately adjusting the relative position of the die 3 with respect to the coating bar 1 and the web 2, particularly the position of the die 3 with respect to the liquid pool 6, as shown in FIG. The coating liquid 4 can be directly supplied to the liquid pool 6.

  Moreover, in the said coating device 10, it is preferable that the die | dye 3 as a coating liquid supply means and the coating bar 1 can move independently. When the die 3 and the coating bar 1 do not move independently, for example, as shown in FIG. 5, when the die 3 and the coating bar 1 are lifted and lowered simultaneously at the end of coating, There is a possibility that the device after the drying step is contaminated due to insufficient drying of the coating film in the subsequent drying step. Therefore, when the application is to be terminated, it is necessary to wait until the coating liquid drips. However, when the die 3 and the coating bar 1 can move independently, for example, as shown in FIG. 6, the die 3 is first moved and retracted to prevent dripping at the liquid receiver 9, and then the coating bar 1. By evacuating the coating, it is possible to terminate the application promptly without causing any trouble when it is desired to end the application. In addition, the application according to the present technology may be performed inline on the web being manufactured, or may be performed offline on the manufactured web.

An apparatus configuration for performing in-line coating on a web being manufactured will be described with reference to FIGS. 18 and 19. FIG. 18 shows an embodiment of a web manufacturing process, and FIG. 19 shows a process when coating is performed in-line during the web manufacturing process of FIG. As shown in FIG. 18, the web manufacturing process includes an extruder 200, a base 201, a casting drum 202, a longitudinal stretching machine 203, a lateral stretching machine 204, and a take-up roll 205. First, a polymer is extruded by the extruder 200. The polymer is formed into a web shape (sheet shape) through the base 201 and the casting drum 202. Thereafter, the formed web is stretched vertically and horizontally by a longitudinal stretching machine 203 and a lateral stretching machine 204, and the stretched web is continuously wound by a winding roll 205. When applying in-line to a web under production, as shown in FIG. 19, for example, a coating device 206 is installed between the longitudinal stretching machine 203 and the lateral stretching machine 204 to apply the coating on the longitudinally stretched web. Do. Here, an example of a sequential biaxial stretching method in which transverse stretching is performed after longitudinal stretching has been shown, but the present coating apparatus may be installed before the simultaneous biaxial stretching method.

FIG. 11 shows a coating apparatus according to another embodiment of the present invention. In FIG. 11, a coating apparatus 11 is such that a die 3 as a coating liquid supply means has a smooth portion 20, and other configurations are the same as those in FIG.
By supplying the coating liquid to the puddle through a smooth part, the discharge unevenness in the width direction that occurs when discharged from a die or nozzle is flattened by the influence of gravity while flowing through the smooth part. Is done. Therefore, a more uniform coating liquid can be supplied by the smooth portion, and unevenness in the thickness of the coating film formed on the web can be reduced.
The coating apparatus using a smooth portion has a configuration similar to the slide coater of Non-Patent Document 1 at first glance. However, in the coating apparatus of the present invention, the coating liquid is supplied to the puddle, and the coating liquid supplied to the puddle once stays there as a puddle, and then a constant amount is applied to the web by the coating bar. It is used for coating film formation. Accordingly, the thickness of the coating film formed on the web does not directly depend on the supply amount of the coating liquid. However, in the above-described slide coater, the supplied coating liquid is applied to the web as it is, so the thickness of the coating film formed on the web is directly affected by the supply amount of the coating liquid. At least in this respect, the coating mechanisms of the two are completely different. Moreover, since the smooth site | part in the coating device of this invention is for flattening the flow of a coating liquid, the objective, an effect | action, and an effect differ from the said slide coater aiming at multilayer lamination.
In the coating apparatus shown in FIG. 11, the coating liquid is supplied from the coating liquid supply means (the die 3 and the smooth portion 20) as in the case of the coating apparatus shown in FIG. Before contacting 2, it is preferable to supply the liquid pool 6 directly and continuously without interruption. At this time, the liquid may be supplied to the surface of the liquid pool, or the tip of a smooth portion may be inserted into the liquid pool and supplied directly to the inside. However, if the tip of the smooth part is inserted deeply, the puddle is disturbed and causes a coating defect. Therefore, the insertion length of the smooth part is preferably within 2 mm from the surface of the puddle.
As a method for adjusting the coating width of the coating liquid applied on the web, it is preferable to monitor the position of the coating end immediately after coating with a camera or the like, and feed back the result to adjust the coating width so that the coating width does not become too wide. . The application width can be adjusted by any one of the discharge amount of the coating liquid pump, the web conveyance speed, the web tension, the viscosity of the coating liquid, the rotation speed of the coating bar, and the pressing amount of the coating bar. . In addition, when the coating width suddenly widens and adjustment is not in time, it is preferable to construct a system that receives a signal from the monitoring camera and urgently stops the conveyance of the web and the coating operation.

An example in which a coating solution is coated on the upper surface of a sheet-like (web-like) polyethylene terephthalate (PET) film using the coating apparatus and coating method of the present invention and the results thereof will be described. In the following, the supply stripe, thickness unevenness, and bubble stripe are those visually confirmed on the film surface after the coating liquid is applied and the coating film is formed on the surface and then the coating film on the surface is dried.
[Example 1]
Using the apparatus shown in FIG. 1, a PET resin sheet extruded from a die onto a casting drum is stretched three times in the longitudinal direction to form a uniaxially stretched film, and the film is continuously conveyed at a speed of 25 m / min. The top surface was coated with a coating solution.

The conditions used are as follows.
・ Liquid supply means: Higuchi die (slit width 90 mm, gap 0.1 mm, land length 30 mm)
・ Distance until the coating liquid falls into the puddle: 40 mm
・ Conveying speed: 25m / min ・ Coating liquid viscosity: 1.5Pa ・ s
・ Application width W: 250 mm
・ Discharge rate: 100 ml / min ・ Coating bar: wire bar (diameter 19 mm, length 300 mm, wire diameter 0.356 mm)
・ Pump: Takumina's diaphragm pump (pulsation rate ± 3.5% range)
The coating width W refers to W in FIG. 20 (the moving mechanism is not shown) as viewed from the top of FIG.

The coating liquid was directly supplied in the form of a thin sheet on the liquid pool formed at the contact portion between the wire bar and the PET film, and coating was performed. As a result of visual observation, supply lines and foam lines were not observed on the coating film surface after drying. However, a slight thickness unevenness in the film width direction was observed.
[Comparative Example 1]
As shown in FIG. 10, coating was performed in the same manner as in Example 1 except that the coating liquid supply position was set above the wire bar. As a result of visual observation, supply streaks and slight thickness unevenness were observed on the coating film surface after drying. Further, 4 to 8 bubble streaks were constantly generated over the entire width of the coating surface, and the traces of the bubble streaks were visually observed even after drying. For this reason, the sheet on which the coating film is formed does not satisfy the quality as a product and becomes a defective product.
[Comparative Example 2]
As shown in FIG. 9, coating was performed in exactly the same manner as in Example 1, except that the coating liquid supply position was above the film surface upstream from the coating bar. As a result of visual observation, supply streaks and thickness unevenness were observed on the coating surface after drying. In addition, 2 to 5 bubble streaks were always generated over the entire width of the coating surface, and the traces of the bubble streaks were visually observed even after drying. For this reason, the sheet on which the coating film is formed does not satisfy the quality as a product and becomes a defective product.
[Example 2]
Coating was performed in the same manner as in Example 1 except that the coating liquid started to fall from the coating liquid supply means and the distance until reaching the liquid pool was 90 mm. As a result of visual observation, it was observed that there were slight supply streaks and thickness unevenness that seemed to have occurred when the coating liquid was supplied on the coating film surface after drying. These slight supply streaks and thickness irregularities can be eliminated by setting the distance within 80 mm.
[Example 3]
As shown in FIG. 3, coating was performed in exactly the same manner as in Example 1 except that the supply of the coating liquid from the die was forced into a discontinuous dropping state. As a result of visual observation, it was observed that supply streaks were generated at locations corresponding to the dripping positions on the coating surface after drying. Further, a slight thickness unevenness was also observed.
[Example 4]
Coating was performed in exactly the same manner as in Example 1 except that a smooth part tip having an arcuate tip was inserted into the liquid pool as shown in FIG. Each condition of the smooth part is as follows.
・ Distance that the coating liquid flows with the upper part opened: 30 mm
-Inclination angle θ: 30 degrees-Tip shape: Arc shape corresponding to the puddle shape As a result of visual observation, two streaks 109 as shown in FIG. 13 were observed on the coating film surface after drying. Each streak 109 was present at a position of 105 mm from the center in the width direction of the coating surface. On the other hand, supply lines, bubble lines, and thickness unevenness were not observed. Therefore, a product having a width of 210 mm (width of the inner portion of the two stripes 109) was obtained from the sheet on which the coating film was formed.
[Example 5]
Using the coating apparatus 11 of the present invention shown in FIG. 11, a smooth part 111 having a flat tip as shown in FIG. 12 was used as a smooth part, and the tip of the smooth part 111 was inserted into a liquid pool. The coating was performed in the same manner as in Example 4 except for the above. As a result of visual observation, no supply streaks, foam streaks, or thickness unevenness were found on the coating surface after drying. On the other hand, streaks 109 were visually observed at positions of 80 mm on the left and right sides from the center in the width direction of the coating surface after drying. The width of the obtained product was 160 mm. This product width of 160 mm is smaller than the product width of 210 mm in Example 4. This indicates that the shape of the tip of the smooth part is preferably an arc shape corresponding to the shape of the liquid puddle in order to manufacture a wider product.
[Example 6]
Using the coating apparatus 11 of the present invention shown in FIG. 11, the inclination angle θ of the smooth portion 111 having the arc 111 at the tip 111 shown in FIG. 13 is set to 70 degrees, and the distance that the coating liquid flows with the upper part opened is shown. Coating was performed in the same manner as in Example 2 except that the thickness was 5 mm. As a result of visual observation, supply lines and foam lines were not observed on the coating film surface after drying. However, a slight thickness unevenness was observed on the coating surface. This slight thickness unevenness can be eliminated by adjusting the inclination angle θ of the smooth portion and the distance that the coating liquid flows with the upper part opened.

  In the coating apparatus and the coating method of the present invention, the coating liquid is supplied to the upper surface of the web by flowing down on a smooth portion whose upper part is open to the outside, or the coating liquid is supplied to the coating liquid. It is characterized by supplying directly to the pool. Due to this feature, it is possible to manufacture a product having a coating film with a good surface on the coating film surface of the product, in which there are no supply lines of coating liquid or bubble streaks due to air mixing. In addition, by selecting the shape of the tip of the smooth part, it is possible to increase the gap in the width direction of the streaks appearing along the longitudinal direction of the web at both ends of the coating surface as much as possible. It is possible to manufacture a product having Furthermore, the coating liquid can be applied in-line to the web using a high-viscosity coating liquid in the web (sheet or film) manufacturing process.

It is a schematic block diagram of the coating device which concerns on one Embodiment of this invention. FIG. 2 is an enlarged side view in the vicinity of a liquid pool in the apparatus of FIG. 1. It is an enlarged side view of the liquid reservoir vicinity which shows a mode in case a liquid dripping. It is explanatory drawing which shows the effectiveness of position adjustment of a coating liquid supply means. It is explanatory drawing which shows generation | occurrence | production of the malfunction when a die | dye and a coating bar do not move independently. It is explanatory drawing which shows generation | occurrence | production prevention of the malfunction when a die | dye and a coating bar can move independently. It is a schematic block diagram of the conventional general metering bar type coating device. It is a schematic plan view which shows the mode of the coating defect generation | occurrence | production in the apparatus of FIG. It is explanatory drawing which shows the mode of the air biting in a conventional apparatus. It is explanatory drawing which shows the mode of another air biting in a conventional apparatus. It is a schematic block diagram of the coating device which concerns on one Embodiment of this invention. It is explanatory drawing which shows the mode (right side) of the stripe which generate | occur | produces when the coating liquid supply means (left side) which has a smooth site | part whose front-end | tip is not circular arc shape, and the means is used. It is explanatory drawing which shows the coating liquid supply means (left side) which has a smooth site | part whose front-end | tip is circular arc shape, and the mode (right side) of the stripe which generate | occur | produces when using the means. It is an arrow view from the Y direction in the apparatus of FIG. It is an enlarged view of the coating bar vicinity which shows one form of application | coating with a coating bar. It is an enlarged view of the coating bar vicinity which shows one form of application | coating with a coating bar. It is a side view which shows a mode at the time of inserting a coating liquid supply means in a liquid pool. It is the schematic which shows one form of the manufacturing process of a web. It is the schematic which showed the process at the time of performing in-line application | coating to the web in manufacture. It is the schematic plan view which showed the application | coating condition of the width direction of the web in the apparatus of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Coating bar 2 Web 3 Die 4 as coating liquid supply means Coating liquid 5 Movement mechanism 6 Puddle 7 Pump 8 Filter 9 Liquid receptacle 10 Coating apparatus 11 in which the coating liquid supply means does not have a smooth part The coating liquid supply means Coating device 20 having a smooth part Smooth part

Claims (19)

  A coating apparatus for applying a coating liquid to the upper surface of a running web by a coating bar, and supplying the coating liquid directly to a puddle formation site in the vicinity of the upstream side of the contact portion between the coating bar and the web. A coating apparatus comprising a coating liquid supply unit.   A coating apparatus for applying a coating liquid to an upper surface of a running web by a coating bar, wherein the coating liquid is supplied to the upper surface of the web at a position upstream from the position of the coating bar. A coating apparatus, comprising: a liquid supply means, wherein the coating liquid supply means has a smooth portion where the coating liquid flows down in a state where an upper portion is opened.   The inclination angle with respect to the horizontal direction of the smooth part is 10 to 60 degrees, and the distance that the coating liquid flows in a state where the upper part is opened is 10 mm or more and 200 mm or less, The coating apparatus as described.   The said coating liquid supply means is located so that a coating liquid may be directly supplied to the liquid pool formation site | part of the upstream vicinity of the contact part of the said coating bar and the said web, The Claim 2 or characterized by the above-mentioned. 3. The coating apparatus according to 3.   The tip of the smooth portion on the coating bar side has a downward concave shape in which both end portions extend downward from the center portion in the width direction of the web. 4. The coating apparatus according to any one of 4 above.   The coating apparatus according to claim 1, wherein the coating liquid supply unit includes a unit that continuously supplies the coating liquid.   The said coating liquid supply means is equipped with a means to make the distance until the coating liquid supplied from this coating liquid supply means falls into a liquid pool within 80 mm, The any one of Claims 1-6 characterized by the above-mentioned. A coating apparatus according to any one of the above.   The coating apparatus according to claim 1, wherein the coating liquid supply unit includes a moving unit that can move independently of the coating bar. The coating apparatus according to claim 8, wherein the moving means can move the coating liquid supply means with respect to the coating bar by a distance in a range of 0.1 to 500 mm during coating of the coating liquid.
  The coating apparatus according to claim 1, further comprising a liquid receiver capable of receiving a coating liquid from the coating liquid supply unit.   A coating method in which a coating liquid having a viscosity of 0.1 to 3.0 Pa · s is applied to the upper surface of a running web by a coating bar, on the upstream side of a contact portion between the coating bar and the web. A coating method, wherein the coating liquid is directly supplied to a liquid pool to be formed by a coating liquid supply means. A coating method in which a coating liquid having a viscosity of 0.1 to 3.0 Pa · s is applied to the upper surface of a running web by a coating bar, and the coating liquid flows down with the upper part opened. A coating method comprising: supplying a coating liquid to a top surface of the web at a position upstream of a position of the coating bar using a coating liquid supply unit having a portion.   The smooth part is characterized in that the inclination angle with respect to the horizontal direction is 10 to 60 degrees, and the coating liquid has a distance of 10 mm or more and 200 mm or less when the upper part is opened. The coating method according to claim 12.   The coating method according to claim 12 or 13, wherein the coating liquid is directly supplied by the coating liquid supply means to a liquid pool formed in a contact portion between the coating bar and the web.   The smooth portion having a concave shape in which both end portions extend downward from a center portion in the width direction of the web whose tip is matched with the outline of a liquid pool is used. 14. The coating method according to any one of 14.   The coating method according to claim 11, wherein the coating liquid supply unit continuously supplies the coating liquid.   The coating method according to any one of claims 11 to 16, wherein a distance until the coating liquid supplied from the coating liquid supply unit falls into a liquid pool is set to 80 mm or less.   The coating method according to any one of claims 11 to 17, wherein a web having a coating liquid formed thereon and a coating film formed on the surface is stretched and dried after coating. A polymer is extruded by an extruder, the polymer is formed into a sheet to form a web, and a coating solution is applied onto the web using the coating method according to claim 11. The manufacturing method of the web which has a coating film on the surface formed.

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