Web transport method, roll and web manufacturing method

Abstract

The present invention provides a web conveying method and roll that can effectively remove liquid even in environments where contamination occurs and in environments where organic solvents are used. [Solution] A web conveying method for transporting a web below the liquid surface of a liquid stored in a liquid tank, comprising a liquid-removing roll for removing liquid adhering to the web after it has been lifted from the liquid, wherein the liquid-removing roll has a wave-shaped surface.

Description

Technical Field

[0001] The present invention relates to a web conveyance method, a method for manufacturing a roll and a web.

Background Art

[0002] As a technique for pulling up and conveying a web from a liquid, for example, the technique disclosed in Patent Document 1 is known. Patent Document 1 discloses a web conveyance device including a liquid drainage roll that drains the treatment liquid adhering to the web pulled up from the treatment liquid stored in a treatment tank. The liquid drainage roll has a plurality of drainage grooves formed on the outer peripheral surface that extend obliquely with respect to the axis from the central portion in the axial direction of the liquid drainage roll toward both ends, and the liquid drainage is performed by accommodating and draining the treatment liquid intervening between the web and the drainage grooves.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] Dirt such as resin deposits may occur in the treatment liquid. When dirt occurs, in the roll unit disclosed in Patent Document 1, the dirt clogs the fine grooves, resulting in a decrease in the discharge amount of the treatment liquid from the fine grooves, insufficient liquid drainage, and the need to periodically stop the production machine and clean the roll unit to remove the dirt from the fine grooves, which causes a problem of a decrease in the operating rate of the production machine.

[0005] Furthermore, highly corrosive solvents such as methylene chloride are sometimes used in the processing solution. While the roll unit in Patent Document 1 preferably has a rubber surface, there was a problem in that the rubber would dissolve or swell due to the highly corrosive solvent, reducing the amount of liquid discharged from the fine grooves and resulting in insufficient liquid drainage.

[0006] The object of the present invention is to solve the above-mentioned problems and to provide a web conveying method that can suitably remove liquid even in environments where contamination occurs and in environments where solvents are used, as well as a roll that can be used in such a method and a method for manufacturing a web. [Means for solving the problem]

[0007] To solve the above-mentioned problems, the present invention has the following configuration. [I] A web conveying method for conveying a web below the liquid surface of a liquid stored in a liquid tank, comprising a liquid-removing roll for removing liquid adhering to the web after it has been lifted from the liquid, wherein the liquid-removing roll has a wave-shaped surface. [II] The web conveying method according to [I], wherein the wave-shaped amplitude of the liquid-sealing roll is 1 mm or more and 20 mm or less. [III] The web conveying method according to [I] or [II], wherein the number of corrugated convex portions of the liquid-sealing roll is 8 or more and 100 or less. [IV] The web transport method according to any one of [I] to [III], wherein the rotational speed of the liquid-squeezing roll in proximity to the web is -100 to 100% of the web transport speed. [V] A roll having a wave-like shape formed on its outer surface and an arithmetic mean surface roughness Ra of 1.6 μm or less. [VI] The roll according to [V], wherein the amplitude of the wave shape is 1 mm or more and 20 mm or less. [VII] The roll according to [V] or [VI], wherein the number of the wavy protrusions is 8 or more and 100 or less. [VIII] A roll used for removing liquid adhering to the web, as described in any of [V] to [VII]. A method for manufacturing a web, comprising the step of removing liquid adhering to the web using a roll described in any of [IX], [V], to [VII]. [Effects of the Invention]

[0008] According to the present invention, it is possible to provide a web conveying method, a roll, and a web manufacturing method that can suitably remove liquid even in environments where contamination occurs and in environments where organic solvents are used. [Brief explanation of the drawing]

[0009] [Figure 1] This diagram schematically illustrates a web transport method according to one embodiment of the present invention. [Figure 2] This figure schematically shows a roll having a wave-like shape formed on its outer surface, which is one embodiment of the present invention. [Figure 3] This is a plan view of a roll having a wave-like shape formed on its outer surface, which is one embodiment of the present invention. [Figure 4] This is an enlarged view of the wave shape in Figure 2. [Figure 5] This diagram schematically shows a web adjacent to a roll, where a wave shape is formed on the outer surface. [Modes for carrying out the invention]

[0010] Embodiments of the web transport method according to the present invention will be described below. Figure 1 is a schematic diagram showing a web transport method according to one embodiment of the present invention. The web transport method shown in Figure 1 is incorporated into a web cleaning device and can transport a web 14 made of a strip-shaped resin film, glass film, metal film, etc., to a processing liquid 13 stored in a processing tank 12 using a roll-to-roll method to clean the web. In Figure 1, there is one processing tank 12, but the web may be transported to two or more processing tanks to clean it. The processing liquid may be a solvent such as water, methylene chloride, methyl ethyl ketone, acetone, ethanol, propanol, or a solution thereof.

[0011] The web conveying method includes an air-transport roll 10 that conveys the web 14 above the liquid surface of the processing liquid 13 stored in the processing tank 12, a liquid-transport roll 11 that conveys the web 14 below the liquid surface of the processing liquid 13 stored in the processing tank 12, an air-transport roll 10' that lifts the web 14 below the liquid surface out of the processing liquid, and a roll 1 that removes the processing liquid adhering to the web 14 lifted by the air-transport roll 10'. The liquid-transport roll 11 is preferably arranged as shown in Figure 1, but is not limited to this, and there may be only one liquid-transport roll 11.

[0012] Roll 1 is positioned above the liquid surface of the processing liquid 13 and upstream of the air-conveying roll 10' in the conveying direction, with its outer surface approaching the rising web 14 at a predetermined gripping angle. The gripping angle is the central angle of the arc-shaped portion where the web 14 contacts the outer surface of Roll 1, and is, for example, 5 to 45 degrees, but is not necessarily limited to this angle range. In this embodiment, two Roll 1s are positioned between the liquid surface of the processing liquid 13 and the air-conveying roll 10', and each is configured to contact both sides of the web 14 to remove the liquid. However, it is also possible to position only one Roll 1 to remove the liquid from only one side of the web 14. The material of Roll 1 is not particularly limited, but it is preferably a metal roll, and more preferably a stainless steel roll. In addition, the surface of Roll 1 may be plated with hard chrome plating or the like. By making Roll 1 out of metal, especially stainless steel, it can be used without corrosion or swelling even in an organic solvent environment.

[0013] Figure 2 is a schematic representation of the axial cross-section of the roll 1 shown in Figure 1. As shown in Figure 2, a wave shape is formed on the outer surface of the roll 1, and the wave shape is composed of a plurality of convex portions 2 and a plurality of concave portions 3. The shape of the convex portions 2 is preferably a smooth curve. If the shape of the convex portions 2 is sharp, there is a risk of scratching the web, but by making them a smooth curve, the effect of suppressing scratches can be preferably obtained. The shape of the concave portions 3 is not particularly limited, but a smooth curve is preferred. It is preferable that the convex portions 2 and the concave portions 3 are connected without any steps. The wave shape formed on the outer surface of the roll 1, when unfolded into a plane, may be a combination of a sine wave, a cycloid curve, and a circular arc.

[0014] Figure 3 is a plan view of a roll having a wave-like shape formed on its outer surface, which is one embodiment of the present invention. The wave-like shape formed on the outer surface of roll 1 is preferably present over 100% of the roll width direction, as shown in Figure 3(a), but is not limited to this. It is preferably present over 50% or more of the roll width direction, more preferably over 70% or more, and even more preferably over 90% or more. Furthermore, it is more preferable that the wave-like shape includes the center in the roll width direction. By having the wave-like shape within the above range, a uniform liquid-cutting effect in the web width direction can be suitably obtained.

[0015] The wave shape formed on the outer surface of roll 1 may be in the same direction as the roll width direction, as shown in Figure 3(a), or in a different direction, as shown in Figure 3(b). Preferably, the direction is within 45° from the roll width direction, more preferably within 30°, and even more preferably within 15°. Also, as shown in Figure 3(c), the wave shape may be formed in a V-shape from the center of the roll width direction toward the roll end. By forming the wave shape as described above, the processing liquid that has been cut off by the wave shape flows from the corrugated recess 2 toward the roll end, and an effect of improving the liquid cutting effect is preferably obtained.

[0016] When the web 14 with the processing liquid adhering to it approaches the convex portion 2 of the roll 1, the processing liquid is bitten between the web 14 and the convex portion 2, causing the web 14 to float upward by a height h from the convex portion 2. The processing liquid that is not bitten remains on the upstream side in the conveyance direction of the web and falls due to gravity or the like. The height h at which the processing liquid is bitten is calculated from the following formula (1). In formula (1), R is the radius of curvature at the apex of the convex portion 2, η is the viscosity coefficient of the processing liquid, Ur is the rotational speed of the roll 1, Uw is the conveyance speed of the web 14, and T is the tension of the web 14.

[0017] h = 0.643R{6η(Ur + Uw) / T}^(2 / 3) ··· (1) Figure 4 is an enlarged view of the waveform in Figure 2. As shown in Figure 4, the difference between the radius of the inscribed circle 4 that touches the apex of the concave portion 3 and the radius of the circumscribed circle 5 that touches the apex of the convex portion 2 is defined as A, and the amplitude of the waveform is set to half of the difference A. In the present invention, the amplitude of the waveform of the roll 1 is preferably 1 mm or more and 20 mm or less. More preferably, it is 5 mm or more and 10 mm or less. By setting the amplitude of the waveform of the roll 1 to be not less than the aforementioned lower limit, the effect of improving the liquid drainage effect can be suitably obtained. Also, by setting the amplitude of the waveform of the roll 1 to be not more than the aforementioned upper limit, the effect of suppressing damage to the web can be suitably obtained.

[0018] In the present invention, the number of convex portions 2 of the waveform of the roll 1 is preferably 8 or more and 100 or less. More preferably, it is 16 or more and 50 or less. By setting the number of convex portions 2 within the aforementioned range, it is possible to sufficiently contact the web while reducing the radius of curvature at the apex of the convex portion 2, and the effect of improving the liquid drainage effect can be suitably obtained.

[0019] Figure 5 is a schematic representation of a web 14 adjacent to the roll 1 shown in Figure 1. In Figure 5, the transport direction B of the web 14 and the rotation direction C of the roll 1 are opposite, but the embodiments of the present invention are not limited to this, and the transport direction B of the web 14 and the rotation direction C of the roll 1 may be the same, or the roll 1 may be stopped. In the present invention, the rotation speed of the roll 1 at the point of proximity to the web is preferably -100% to 100% of the transport speed of the web 14, and more preferably -100% or more and less than 0, or greater than 0 and 100% or less. If the rotation speed of the roll 1 at the point of proximity to the web is positive, the transport direction B of the web 14 and the rotation direction C of the roll 1 are in the same direction, and if it is negative, the transport direction B of the web 14 and the rotation direction C of the roll 1 are in opposite directions. By setting the rotation speed of the roll 1 at the point of proximity to the web 14 to -100% to 100% of the transport speed of the web 14, the effect of suppressing scratches and tears on the film can be suitably obtained. By setting the conveying speed of the web 14 to -100% or more and less than 0 or greater than 0 and less than or equal to 100%, the generated dirt is dispersed across each protruding portion 2, thus effectively suppressing its accumulation in one place on the roll.

[0020] In one aspect of the present invention, the surface of the roll 1 preferably has an arithmetic mean roughness Ra of 1.6 μm or less. More preferably, it is 0.01 μm or more and 0.8 μm or less. Even more preferably, it is 0.01 μm or more and 0.4 μm or less. Most preferably, it is 0.01 μm or more and 0.2 μm or less. By setting the arithmetic mean roughness Ra of the surface of the roll 1 within the above range, it is expected that the accumulation of dirt and the scratching of the film can be suppressed. By setting the arithmetic mean roughness Ra to 0.01 μm or more, it is possible to prevent an increase in costs. The arithmetic mean roughness Ra in the present invention is determined by the method specified in JIS B0601 (2001), and the specific conditions are as follows. A handheld contact-type two-dimensional roughness meter was used as the measuring device, and the corrugated convex portion of the roll 1 was measured along the roll width direction. The measurement conditions were a cutoff of 0.08 mm and a measurement length of 0.4 mm.

[0021] Although the web transport method of this embodiment is shown as being incorporated into a web washing device, it can be suitably used in various manufacturing methods in which a strip-shaped web is guided below the liquid surface of a processing liquid stored in a processing tank, and then lifted up and transported. For example, it can be suitably used in a manufacturing method for producing a polarizing film from a polyvinyl alcohol-based resin film, specifically for transporting the polyvinyl alcohol-based resin film into the processing liquid stored in a processing tank. For example, it can be suitably used in a manufacturing method for producing a separator by washing away an inorganic filler or plasticizer from a film-like polyolefin resin composition containing an inorganic filler or plasticizer, specifically for transporting the film-like polyolefin resin composition into the washing liquid stored in a washing tank.

[0022] One aspect of the present invention is a method for manufacturing a web that includes a step of removing liquid adhering to the web using the aforementioned roll. For example, it can be used in a manufacturing method for producing a polarizing film from a polyvinyl alcohol-based resin film, specifically in the step of removing the liquid from the processing solution when transporting the polyvinyl alcohol-based resin film into the processing solution stored in a processing tank. Alternatively, it can be suitably used in a manufacturing method for producing a separator by washing away an inorganic filler or plasticizer from a film-like polyolefin resin composition containing an inorganic filler or plasticizer, specifically in the step of removing the liquid when transporting the film-like polyolefin resin composition into the washing solution stored in a washing tank. [Examples]

[0023] Below, we have calculated the liquid-cutting effect of a roll with a wave-shaped outer surface and a smooth roll using equation (1). Note that this embodiment is not limited to these examples.

[0024] [Example 1] The liquid thickness h was estimated under the following conditions: the radius of the circumscribed circle 5 is 40 mm, the number of convex portions 2 is 16, the amplitude of the wave shape is 5 mm, the radius of curvature at the apex of the convex portion 2 is 5 mm, the arithmetic mean roughness Ra of the surface of roll 1 is 0.8 μm, the viscosity of the processing liquid is 1 mPa·s, the rotation speed of roll 1 is -50 m / min, the conveying speed of web 14 is 100 m / min, and the tension of web 14 is 400 N / m. Roll 1 used had a wave shape provided across the entire width direction of the roll (100%), and the wave shape was provided parallel to the width direction of the roll. The liquid thickness h obtained in this way is shown in Table 1.

[0025] [Examples 2-6, Comparative Example 1] The liquid thickness h was estimated under the same conditions as in Example 1, except for the changes shown in the table. Comparative Example 1 used a smooth roll without a wave shape formed on its outer surface. From the above results, it can be seen that the liquid thickness h is small in Examples 1 to 6 which satisfy the present invention, and the liquid thickness h is large in Comparative Example 1 which does not satisfy the present invention, thus a favorable effect of improving the liquid cutting effect can be obtained by applying the present invention.

[0026] [Table 1] [Explanation of Symbols]

[0027] 1: Roll 10, 10': Air-conveyed conveying rolls 11: Liquid-transfer roll 12: Treatment tank 13: Processing liquid 14: Web 2: Convex part 3: Concave part 4: Inscribed circle 5: Circumscribed circle 6: The vertex of the convex part 7: Vertex of the recessed area A: The difference between the radii of the inscribed circle and the circumscribed circle. B: Web transport direction C: Roll rotation direction h: Height at which the processing solution is trapped

Claims

1. A web transport method for transporting a web below the liquid surface of a liquid stored in a liquid tank, It is equipped with a liquid-removing roll that removes any liquid adhering to the web after it has been lifted from the liquid, The aforementioned liquid-sealing roll has a corrugated shape formed on its outer surface. Web transport method.

2. The amplitude of the corrugated shape of the liquid-sealing roll is 1 mm or more and 20 mm or less. The web transport method according to claim 1.

3. The number of corrugated protrusions on the aforementioned liquid-sealing roll is between 8 and 100. The web transport method according to claim 1.

4. The rotational speed of the liquid-sealing roll in proximity to the web is between -100% and 100% of the web's transport speed. A web transport method according to any one of claims 1 to 3.

5. A wave-like shape is formed on the outer surface. The arithmetic mean surface roughness Ra is 1.6 μm or less. roll.

6. The amplitude of the waveform is 1 mm or more and 20 mm or less. The roll according to claim 5.

7. The number of the aforementioned wavy convex portions is between 8 and 100. The roll according to claim 5.

8. Used to remove liquids that adhere to the web. The roll according to any one of claims 5 to 7.

9. Using the roll described in any one of claims 5 to 7 The process includes removing any liquid adhering to the web. Web manufacturing method.

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