JP2022107148A - Coating head, and manufacturing device and manufacturing method of web with coating - Google Patents

Abstract

To provide a double-side coating head capable of suppressing stripe generated due to foreign substances, and simultaneously forming coatings of high quality on both surfaces of a web.SOLUTION: A coating head 100 has liquid storage portions X1 and X2 for storing a coating liquid, which is formed by a pair of liquid storage members 101 and 101' opposite to a web 1 traveling surface, and a metering portion Y for adjusting a coating to a desired thickness, which is formed by a pair of metering members 104 and 104' oppositely provided at an interval across the web traveling surface on the downstream side in a web traveling direction of the liquid storage portion. Between an inlet of the web and an outlet of the web, there are one or more places where an interval between the pair of liquid storage members is narrowed, and by this places, it is divided into a plurality of liquid storage portions aligned in the web traveling direction. The liquid storage portion located on the most downstream side in the web traveling direction has small capacity as compared with other liquid storage portions. At a part communicating to the metering portion, an interval between the pair of liquid storage members is gradually narrowed toward the downstream side in the web traveling direction.SELECTED DRAWING: Figure 1

Description

The present invention relates to a coating device for simultaneously forming a coating film on both surfaces of a film, a non-woven fabric, paper, etc., and a manufacturing method.

Conventionally, in the double-sided simultaneous coating method in which a coating film is formed on both sides of the web at the same time, coating heads such as bars, rolls, knives, and slit dies are arranged facing each other on the front and back surfaces of the web to form a high-quality coating film on both the front and back surfaces. There are widely known ways to do this.

As an example of such a coating head, Patent Document 1 discloses a coating head having a measuring unit provided at a predetermined interval and a liquid storage unit for storing a coating liquid above the measuring unit. Also disclosed is a method of manufacturing a coated web in which a web is passed through a liquid storage portion and a measuring portion of the coating head to apply a coating liquid to both sides of the web at the same time.

In such a double-sided simultaneous coating method, coating defects due to running wrinkles on the web, coating unevenness in which the film thickness distribution becomes uneven, or coating streaks generated by foreign matter being caught between the measuring part of the coating head and the web. Can be a problem.

In response to the problem of poor coating due to running wrinkles on the web, Patent Document 2 includes a measuring unit provided at a predetermined interval and a liquid storage unit for storing the coating liquid above the measuring unit, as in Patent Document 1. Disclosed is a method of reducing running wrinkles of the web by providing a groove in the middle of the measuring surface in the width direction of the web.

Further, for foreign matter caught between the measuring part of the coating head and the web, different measures are taken depending on the origin of the foreign matter. The foreign matter brought into the coating head can be roughly classified into foreign matter derived from the surrounding environment, foreign matter derived from the coating liquid, and foreign matter adhering to the web. As a measure against foreign substances derived from the surrounding environment, it is common to apply in a clean room or a clean booth in the web manufacturing process with a coating film. Further, foreign matter derived from the coating liquid can be suppressed by providing a filter for collecting the foreign matter in the liquid feeding path of the coating liquid from the liquid feeding tank to the coating head.

Regarding the remaining foreign matter adhering to the web, in a coating head having a measuring portion provided with a predetermined gap and a liquid storage portion for storing the coating liquid above the measuring portion as in Patent Document 1, the web is inside the coating head. Since the foreign matter adhering to the web is directly carried into the liquid storage part and the measuring part of the coating head, the foreign matter is likely to be caught between the measuring part and the web. The pinching of foreign matter in the measuring part causes a coating streak, which is a big problem.

Although the main purpose is not to prevent foreign matter adhering to the web from being caught between the measuring part of the coating head and the web, Patent Document 3 states that a liquid having a lower viscosity and a lower surface tension than the coating liquid is applied to both sides of the web. A method of pre-coating is disclosed. An embodiment of Patent Document 3 discloses that by pre-coating, foreign matter adhering to the web can be washed away and foreign matter can be prevented from being caught between the web and the coating head.

JP-A-2017-77544 JP-A-2018-75531 Japanese Unexamined Patent Publication No. 2008-36607

However, since the coating head disclosed in Patent Document 3 requires a pre-coating process and an ironing roll in addition to the coating process, the equipment becomes large and the web manufacturing process with a coating film becomes complicated, and the pre-coating process is complicated. This will lead to an increase in the cost of the coating liquid used for coating.

In this way, in the coating head having the measuring unit provided at a predetermined interval and the liquid storage unit for storing the coating liquid above the measuring unit, coating streaks caused by foreign matter are generated without providing an additional step. No coating head has been found that can perform stable coating without any problem.

Therefore, the present invention provides a double-sided coating head capable of simultaneously forming a high-quality coating film on both sides of a web without generating coating streaks caused by foreign matter.

The coating head of the present invention that solves the above problems is a coating head that simultaneously applies a coating liquid to both sides of a traveling web.
A liquid storage unit for storing the coating liquid, which is formed by a pair of liquid storage members facing the web running surface,
For adjusting the coating film to a desired thickness, which is formed by a pair of measuring members provided so as to sandwich the running surface of the web on the downstream side in the running direction of the web from the liquid storage portion. It has a measuring part and
In the liquid storage unit, there is one or a plurality of places where the distance between the pair of liquid storage members is narrowed from the entrance where the web enters to the exit where the web goes out, depending on the place where the distance is narrowed. , It is divided into multiple liquid storage parts that line up in the running direction of the web,
Of the above-classified liquid storage parts, the liquid storage part located on the most downstream side in the web traveling direction has a smaller volume than the other liquid storage parts, and is a part communicating with the measuring part on the downstream side in the web traveling direction. The distance between the pair of liquid storage members is gradually narrowed toward the direction of.

In addition, the coating film-coated web manufacturing apparatus of the present invention includes the coating head of the present invention and a transport device for transporting the web.

Further, in the method for producing a web with a coating film of the present invention, using the coating head of the present invention, the web is introduced into and passed through the liquid storage section and the measuring section of the coating head, and the web is introduced in the liquid storage section. A coating film having a desired thickness is formed on both sides of the web by adhering the coating liquid stored in the liquid storage portion to both sides of the web and adjusting the gap between the measuring portion and the running surface of the web.

By using the coating head of the present invention, it is possible to suppress streaks generated due to foreign matter and simultaneously form a high-quality coating film on both sides of the web.

It is the schematic sectional drawing of the coating head by one Embodiment of this invention. It is an enlarged view of the 2nd liquid storage part of the coating head of FIG. 1, and is the figure which shows the flow direction of the coating liquid at the time of coating. It is an enlarged view of the 2nd liquid storage part of the coating head which is different from this invention, and is the figure which shows the flow direction of the coating liquid at the time of coating. It is the schematic sectional drawing of the coating head by another embodiment of this invention. It is the schematic which shows an example of the web manufacturing apparatus with a coating film of this invention.

A preferred embodiment of the present invention will be described with reference to the drawings. However, the present invention is not limited to the form shown in the drawings, and various changes may be made as long as the object of the invention can be achieved and the gist of the invention is not deviated.

See FIG. FIG. 1 is a schematic cross-sectional view of an embodiment of the coating head 100 of the present invention. When the web 1 passes through the coating head 100, the coating liquid 2 is applied to both surfaces of the web 1, and the web 3 with a coating film is formed. The inside of the coating head 100 includes a liquid storage unit X for storing the coating liquid and a measuring unit Y for adjusting the coating film to a desired thickness. Further, the liquid storage unit X is further divided into a first liquid storage unit X1 and a second liquid storage unit X2 in order from the upstream side in the web traveling direction by a pair of dividing members 103 and 103'.

The coating head 100 is composed of a first liquid storage member 101 and 101', a second liquid storage member 102 and 102', a partitioning member 103, 103', and a pair of measuring members 104 and 104'. The first liquid storage members 101 and 101'are the inner wall surface of the first liquid storage unit X1 for storing the coating liquid 2. The dividing members 103 and 103'are arranged to face each other with a narrow gap t1 so as to sandwich the traveling surface of the web 1 on the downstream side in the traveling direction of the web 1 from the first liquid storage members 101 and 101'. A first liquid storage unit X1 is formed together with the first liquid storage members 101 and 101'as the bottom surface of the first liquid storage unit X1. The second liquid storage members 102 and 102'are the inner wall surface and the bottom surface of the second liquid storage portion X2 for storing the coating liquid 2. The measuring members 104 and 104'are arranged to face each other with a narrow gap t so as to sandwich the traveling surface of the web 1 on the downstream side in the traveling direction of the web 1 from the second liquid storage members 102 and 102'. By adjusting this gap t, the coating film has a desired thickness.

The liquid storage unit X includes a liquid storage member composed of a first liquid storage member 101, a second liquid storage member 102, and a partitioning member 103, a first liquid storage member 101', a second liquid storage member 102', and a liquid storage member X. When viewed as being composed of a liquid storage member composed of the partitioning member 103', the pair of liquid storage members of the liquid storage unit X has a narrow interval at a portion sandwiched between the partitioning members 103 and 103'.

The volume of the second liquid storage unit X2 is smaller than that of the first liquid storage unit X1, and the surfaces of the second liquid storage members 102 and 102'that communicate with the measuring members 104 and 104' run on the web 1. It is formed so as to approach the running surface of the web 1 toward the downstream side in the direction.

Although not shown, in the coating head 100, the first liquid storage member 101 is provided on the front side and the back side of the paper surface of FIG. Side plates are provided so as to sandwich the 101', the second liquid storage members 102, 102', the dividing members 103, 103', and the measuring members 104, 104'.

Here, the first liquid storage members 101, 101', the second liquid storage members 102, 102', and the dividing member 103 when the coating film is formed on both sides of the web using the coating head 100 of the present invention. , 103'and the weighing members 104, 104' will be described in detail.

When manufacturing the coated web 3, the web 1 first enters the first liquid storage portion X1 of the coating head 100, and then passes through the gap t1 of the dividing members 103, 103'and the second storage. Enter the liquid part X2. Foreign matter adhering to the web 1 in advance also enters the first liquid storage unit X1 and then enters the dividing members 103 and 103'. At this time, a foreign substance larger than the gap t1 of the dividing members 103 and 103'cannot pass through the gap of the dividing members 103 and 103'and does not enter the second liquid storage unit X2, so that the second liquid storage unit X2 The web from which the foreign matter has been removed enters the space, and then passes through the measuring unit Y. As a result, it is possible to suppress the generation of streaks due to foreign matter adhering to the web.

Next, the appearance of the coating liquid 2 in the second liquid storage unit X2 and the measuring unit Y when the coating film is formed on both sides of the web using the coating head 100 of the present invention will be described in detail with reference to FIG. explain. FIG. 2 shows the details of the second liquid storage portion X2 in the coating head 100 and the flow direction of the coating liquid 2 existing in the second liquid storage portion X2 at the time of coating.

In the present invention, the volume of the second liquid storage unit X2 is made smaller than the volume of the first liquid storage unit X1. As a result, the residence time of the coating liquid 2 in the second liquid storage unit X2 can be shortened, so that deterioration of the coating liquid 2 and reaggregation of solid content can be suppressed, and the solid content can be suppressed in the second liquid storage unit X2. It is possible to prevent foreign matter from being generated and adhering to the web 1. That is, it is possible to suppress the occurrence of coating streaks caused by foreign matter. Further, the second liquid storage members 102 and 102'are formed so that the surface communicating with the measuring members 104 and 104'approaches the traveling surface of the web 1 toward the downstream side in the traveling direction of the web 1. As a result, the flow of the coating liquid as shown by the arrow in FIG. 2 is formed in the second liquid storage portion X2, and the flow of the coating liquid 2 extends to the bottom corner of the second liquid storage portion X2. As a result, since the coating liquid does not stay on the bottom surface of the second liquid storage unit X2, deterioration of the coating liquid 2 and reaggregation of the solid content in the second liquid storage unit X2 are suppressed, and the second storage is suppressed. It is possible to prevent foreign matter from being generated in the liquid portion X2 and adhering to the web 1. That is, it is possible to suppress the occurrence of coating streaks caused by foreign matter.

Here, as a comparison, the second liquid storage unit X2'and the measuring unit Y when the coating film is formed by using the coating head 200 in which only the coating head 100 and the second liquid storage unit X2 of the present invention are different. The aspect of the coating liquid 2 in ′ will be described in detail with reference to FIG. FIG. 3 is an enlarged view of the second liquid storage portion X2'of the coating head 200, which is different from the present invention, and is a diagram showing the flow direction of the coating liquid 2 at the time of coating. Unlike the coating head 100 of the present invention, the coating head 200 has a surface of the second liquid storage members 202, 202'that communicates with the measuring members 204, 204' toward the downstream side in the traveling direction of the web 1. Not close to the running surface. Other configurations are the same as those of the coating head 100 of the present invention. In this case, as shown by the arrow in FIG. 3, in the coating head 200, the flow in the second liquid storage portion X2'does not reach the bottom corner of the second liquid storage portion X2', and the coating is applied. Liquid retention portions Z and Z'are formed. As a result, foreign matter may be generated due to deterioration or reaggregation of the coating liquid 2 and adhere to the web 1. That is, coating streaks caused by foreign matter are generated.

In the present embodiment shown in FIG. 2, the surface of the second liquid storage member 102, 102'that communicates with the measuring members 104, 104'is a flat surface, but in the present invention, the second liquid storage member 102 As long as the surface communicating with the measuring members 104 and 104'of 102'approaches the traveling surface of the web 1 toward the downstream side in the traveling direction of the web 1, the surface is not limited to a flat surface and may be a curved surface.

The gap t1 of the dividing members 103 and 103'can be variously changed within a range that does not deviate from the gist of the invention, but is determined by the physical properties of the coating liquid 2 to be used, the size of the foreign matter to be captured, and the gap t of the measuring unit Y. Is preferable. Assuming that the thickness of the web 1 is Wt (mm), the gap t1 (mm) of the dividing members 103 and 103'is preferably determined within a range satisfying Wt + 0.005 mm ≦ t1 ≦ Wt + 0.3 mm. When the interval t1 is (Wt + 0.005 mm) or more, the dividing members 103 and 103'are less likely to come into contact with the web 1 or the transport resistance of the web 1 is increased so that the web 1 is less likely to break. When the interval t1 is (Wt + 0.3 mm) or less, the dividing members 103 and 103'can capture foreign matter having a size normally assumed.

Further, when the liquid storage unit X is divided into three or more by a plurality of dividing members, it is preferable that the gap between the respective dividing members is determined according to the size of the foreign matter captured by each dividing member. More preferably, the gap between the dividing members is gradually narrowed from the upstream side to the downstream side in the traveling direction of the web 1. As a result, foreign matter of different sizes can be efficiently captured.

Further, in order to suppress the deterioration of the coating liquid 2 in the second liquid storage portion X2, the second liquid storage portion X2 may be filled with the coating liquid 2 to avoid contact between the coating liquid 2 and the air. preferable. When the coating liquid 2 has a low viscosity, the air remaining in the second liquid storage portion X2 can be eliminated by filling the liquid storage portion X with the coating liquid 2, but the viscosity of the coating liquid 2 is high. If air remains in the second liquid storage unit X2 even after the liquid storage unit X is filled with the coating liquid 2 for some reason, the second liquid storage unit X2 is filled with the coating liquid at the initial stage. It is preferable to eliminate the remaining air. Specifically, a method of reducing the pressure on the downstream side of the coating head 100, or just before the start of coating, the dividing members 103 and 103'of the coating head 100 are moved in the thickness direction of the web 1 to create a gap between the dividing members 103 and 103'. Examples include, but are not limited to, a method of widening t1 and then returning it to a predetermined gap.

It is known that the thickness of the coating film when the coating film-coated web 3 is formed by using the coating head 100 of the present invention is approximately half of the gap between the measuring members 104 and 104'and the surface of the web 1. The gap t of the measuring portion Y is determined by the desired thickness of the coating film and the thickness Wt of the web 1. That is, the installation positions of the measuring members 104 and 104'are determined. Further, at this time, since the surfaces of the measuring members 104 and 104'in contact with the coating liquid 2 are parallel to the traveling surface of the web 1, the hydraulic pressures on both sides of the web 1 are equal, so that both sides of the web 1 are equal. Has the effect of making the thickness of the coating film uniform.

As described above, since the thickness of the coating film depends on the installation position of the measuring members 104 and 104', the coating head 100 may be provided with means (not shown) capable of moving the measuring members 104 and 104'in the thickness direction. preferable. As such a means, a moving table or the like on which the measuring members 104 and 104'are mounted and the measuring members 104 and 104' can be moved together with the measuring members 104 and 104'in the thickness direction of the web 1 can be exemplified. By providing such a means of transportation, the thickness of the coating film can be adjusted uniformly and easily with good reproducibility. As a result, the coating head 100 can be installed with the same gap t regardless of the operator. Further, in order to continuously manufacture the web 3 with a coating film, when the seam in which the old and new webs 1 are bonded with tape or the like passes through the measuring members 104 and 104', there is a gap between the measuring members 104 and 104'. Move in the direction of widening. At that time, it is preferable that the gap between the web 1 and the measuring members 104, 104'moves in the same gap with the web 1 in between.

As described above, if the coating head according to the present invention is used, a coating film can be formed on both sides of the web at the same time without generating streaks caused by foreign matter. The manufacturing apparatus can manufacture a high-quality coated web without streaks caused by foreign matter.

It is preferable that the coating head 100 is composed of the first liquid storage members 101, 101', the second liquid storage members 102, 102', the dividing members 103, 103', and the measuring members 104, 104'. , Each member may be an integral part. Further, each member may be composed of a plurality of parts.

FIG. 4 is a schematic cross-sectional view of the coating head 300 according to another embodiment of the present invention. The coating head 300 has rounded corners on the upstream side of the running surface of the web 1 among the corners of the sorting members 303 and 303'that face the running surface of the web 1. As a result, even when the web 1 is pressed toward the dividing member 303'(303) by the foreign matter captured between the dividing member 303 (303') and the web 1, and comes into contact with the dividing member 303'(303), even if the web 1 comes into contact with the dividing member 303'(303). Web 1 is less likely to be torn or scratched.

Next, the web manufacturing apparatus 4 with a coating film using the coating head 100 of the present invention will be described with reference to FIG. FIG. 5 is a schematic view showing a web manufacturing apparatus with a coating film of the present invention. However, the present invention is not limited to the form shown in the drawings.

As shown in FIG. 5, the web manufacturing apparatus 4 with a coating film using the coating head 100 of the present invention has an unwinding portion 5, a coating head 100, and an aftertreatment device 7 that unwind the web 1 in this order from the upstream side in the web traveling direction. , A winding unit 6 for winding the web 1 is provided, and a transport roller is arranged between the winding units 6. Examples of the post-treatment device 7 include a dryer for drying and solidifying the coating film.

Next, a method for manufacturing the coated web 3 using the coating head 100 of the present invention will be described.

The coated web 3 is manufactured by passing the web 1 through the gaps between the measuring members 104 and 104'after passing through the liquid storage portion X of the coating head 100. At this time, since the coating liquid 2 stored in the liquid storage unit X decreases with the application, the storage amount of the coating liquid 2 is managed, and the coating liquid 2 is supplied to the liquid storage unit X to store a certain amount or more. By maintaining the above, the web 3 with a coating film can be stably produced. As a means for managing the stored amount of the coating liquid 2, a method of detecting the liquid level of the coating liquid 2 in the liquid storage unit X with a liquid level sensor or the like can be exemplified. As a means for supplying the coating liquid 2, a method of supplying the coating liquid 2 by a liquid feeding pump or the like in response to a signal from a liquid level sensor or the like can be exemplified. However, neither means is limited to this method. Further, the coating liquid 2 is supplied when the liquid level sensor or the like detects that the liquid level has dropped to a predetermined height, even if the coating liquid consumption amount due to coating is calculated and constantly supplied. However, it may be in the form of intermittently supplying a fixed amount of the coating liquid 2.

Further, it is preferable to provide a means for measuring the thickness of the coating film on the running web after the coating film is formed by the coating head 100. When the measurement result of the coating film thickness deviates from the standard, the web 3 with a coating film having a desired thickness can be manufactured by adjusting the gap t between the pair of measuring members 104 and 104'. Specifically, if the coating film is larger than the desired thickness, the gap t is narrowed, and if it is small, the measuring members 104 and 104'are moved in the direction of widening the gap t.

The present invention can be applied to a coating head that simultaneously forms a coating film on both sides of a web such as paper, film, metal thin film, or cloth, and a coating film-coated web manufacturing apparatus and manufacturing method provided with the coating head. It is not limited to.

1 Web 2 Coating liquid 3 Coating web 4 Coating coating web manufacturing equipment 5 Unwinding part 6 Winding part 7 Post-treatment device 100 Coating head 200 Coating head 300 Coating head 101, 101'First liquid storage member 102, 102'Second liquid storage member 103, 103' Separation member 104, 104'Measuring member 202, 202' Second liquid storage member 203, 203' Dividing member 204, 204' Measuring member 303, 303' Sorting member X storage Liquid part X1 First liquid storage part X2 Second liquid storage part Y Measuring part X2'Second liquid storage part Y'Measuring part Z, Z'Coated liquid retention part t Direction perpendicular to the web surface of the measuring part Y Gap t1 Gap in the direction orthogonal to the web surface of the dividing member

Claims (3)

A coating head that applies the coating liquid to both sides of the running web at the same time.
A liquid storage unit for storing the coating liquid, which is formed by a pair of liquid storage members facing the web running surface,
For adjusting the coating film to a desired thickness, which is formed by a pair of measuring members provided so as to sandwich the traveling surface of the web on the downstream side in the traveling direction of the web from the liquid storage portion. It has a measuring part and
The liquid storage unit is
Between the entrance where the web enters and the exit where the web exits, there is one or more places where the distance between the pair of liquid storage members is narrowed.
It is divided into a plurality of liquid storage portions arranged in the traveling direction of the web according to the location where the interval is narrowed.
Of the classified liquid storage parts, the liquid storage part located on the most downstream side in the web traveling direction is
The volume is smaller than other liquid storage parts,
In the portion communicating with the measuring portion, the distance between the pair of liquid storage members gradually narrows toward the downstream side in the traveling direction of the web.
Coating head. A coating film-coated web manufacturing apparatus including the coating head according to claim 1 and a transport device for transporting the web. Using the coating head of claim 1, a web is introduced into and passed through the liquid storage portion and the measuring portion of the coating head, and in the liquid storage portion, the coating liquid stored in the liquid storage portion is applied to both sides of the web. A method for producing a web with a coating film, which forms a coating film on both sides of the web by adhering the measuring portion and adjusting the gap between the measuring portion and the running surface of the web.

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