JP2006263617A - Coating method of coating solution, coating apparatus of coating solution, and optical film - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a coating method of a coating solution and a coating apparatus thereof which can reduce fluttering of a web near a coating section, and to provide an optical film including a coating layer obtained by the coating apparatus and the coating method. <P>SOLUTION: Guide rollers 12, 68 are so arranged that a roll span L<SB>A</SB>relating to the guide roller 68 arranged in the first place to an upstream side from the coating section 84 and a roll span L<SB>B</SB>relating to the guide roller 68 arranged in the first place from the coating section 84 to the upstream side satisfy 50mm≤L<SB>A</SB>≤500 mm, 50mm≤L<SB>B</SB>≤500 mm. The coating solution is discharged from a slot die 18 toward the surface of a support 14 conveyed by the guide rollers 12, 68 such that the wet coating film of the coating layer is ≤20 μm. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a coating liquid coating method, a coating liquid coating apparatus, and an optical film, and more particularly to a technique for forming a coating layer of good quality on a support.

  Conventionally, as a coating device for coating a coating film (coating layer) with a desired thickness on the surface of a web (support), a slot die coater method such as a bar coater method, a reverse roll coater method, a gravure roll coater method, an extrusion coater, etc. , Etc. are known. Among these, slot die coater type coating apparatuses are frequently used because they can coat thin layers at a higher speed than other systems.

  In the slot die coater system represented by the extrusion coater, the coating liquid is applied by laying a bead between the web and the slot die, but the coating liquid is applied to the web by preventing so-called uneven coating. Therefore, it is important to suppress flapping of the web in order to apply uniformly. Due to the flapping of the web, the variation in the coating amount of the coating liquid easily occurs, and surface defects such as unevenness are caused in the coating film on the web. In particular, when the coating amount is low such that the wet film thickness is 20 μm or less, the bead holding ability is weakened, and surface defects such as unevenness are likely to be caused in the coating film.

Against this background, for example, Patent Document 1 proposes a coating method that regulates web conveyance unevenness at the coating roller position. The purpose of this coating method is to prevent stepwise coating unevenness from occurring on the coating layer surface even in the case of thin layer coating by directly driving the feed roller and coating roller with a multipolar motor.
JP-A-2005-46656

  However, the coating method using the direct drive disclosed in Patent Document 1 does not focus on the web fluttering itself, and depending on the conditions, the web fluttering may not be suppressed. In addition, there is no other technical document that focuses on suppressing flapping of the web.

  In general, the flapping phenomenon of the web is often treated approximately as a string vibration phenomenon between guide rollers carrying the web. Factors that affect the fluttering of the web include equipment, processes such as roll span indicating the distance between the guide rollers, web tension, external force acting on the web such as wind and roll eccentricity of the guide roller, etc. Or the factor based on disturbance etc. is mentioned. Therefore, there is a demand for a new proposal for controlling the fluttering of the web by adjusting these factors that affect the fluttering of the web.

  The present invention has been made in view of the above-described circumstances, and an object of the present invention is to provide a coating liquid coating method and a coating apparatus that reduce the flapping of the web by changing the coating liquid coating conditions, and such a coating apparatus and a coating apparatus. It is providing the optical film containing the coating layer obtained by a method.

In order to achieve the above object, according to the first aspect of the present invention, the coating liquid is discharged from the slot die toward the surface of the support conveyed by the plurality of guide rollers, and the gap between the slot die and the support is determined. Further, the present invention relates to a coating solution coating method in which a bead of the coating solution is erected and the coating solution is coated on the surface of the support by the bead to form a coating layer having a wet film thickness of 20 μm or less. The coating liquid coating method includes an upstream first guide roller disposed first on the upstream side from a coating section where the coating liquid is coated on the support by the slot die, and the upstream side of the guide roller. _A roll span LA with the guide roller adjacent to the downstream side with respect to the first guide roller, an upstream second guide roller and the upstream side of the guide roller that are secondly arranged upstream from the application section. A roll span L _B with the first guide roller, and a roll span L _C between the upstream third guide roller and the upstream second guide roller, which are arranged third from the application section to the upstream side among the guide rollers. Each satisfy 50 mm ≦ L _A ≦ 500 mm, 50 mm ≦ L _B ≦ 500 mm, and 50 mm ≦ L _c ≦ 500 mm.

According to the present invention, the roll spans L _A , L _B , and L _c are set to 50 mm or more and 500 mm or less at a low coating amount in which the wet film thickness of the coating layer is 20 μm or less, and fluttering of the support is effectively suppressed. Is done. As a result, the support can be transported in a state in which fluttering is suppressed even when the amount of coating is low, which requires stable transport of the support, and the coating liquid discharged from the slot die can be applied onto the support. A highly accurate coating layer can be formed.

The “applying portion” here means a portion where the coating liquid is discharged from the slot die onto the support in a broad sense, and in a narrow sense, a coating liquid formed between the slot die and the support. It means the contact portion between the bead and the support. Further, the “upstream side” and “downstream side” here are based on the transport direction of the support. Further, “upstream from the application part” means the upstream side of the application part and does not include the application part itself. The “wet film thickness” means the film thickness of the coating layer in a wet state, and mainly refers to the film thickness of the coating layer immediately after being coated on the support until drying. “Roll span” means an index indicating the size of a support supported by adjacent guide rollers in a broad sense, and means a distance between rotation centers of adjacent guide rollers in a narrow sense. In addition, it is also possible to set a state quantity in which characteristics such as the surface shape and the diameter of the guide roller are appropriately added as the roll span. The “roll span L _A between the upstream first guide roller and the guide roller adjacent to the upstream side first guide roller on the downstream side” is, for example, a backup roller (coating roller) in the coating portion. When a guide roller is arranged, it refers to the roll span between the backup roller and the upstream first guide roller, and when a guide roller such as a backup roller is not arranged in the application unit, it is downstream from the application unit. It refers to the roll span between the first guide roller disposed on the first side and the upstream first guide roller.

  In addition, as described in claim 2, the tension of the support disposed between the upstream third guide roller and the application unit may be 150 N or more per 1 m of the width of the support. . In this case, the support is conveyed to the application unit in a tensioned state, and flapping of the support in the application unit is effectively reduced.

  According to a third aspect of the present invention, the flutter of the support body between the upstream first guide roller and the coating portion may be less than 1 mm. It is possible to form a highly accurate coating layer on the support by setting the flutter of the support between the coating unit and the upstream first guide roller to less than 1 mm.

  Further, as described in claim 4, the wind speed of the wind blown against the support disposed between the upstream third guide roller and the coating unit is perpendicular to the film surface of the support. The component may be 2 m / s or less. In this case, the influence of wind that can act as a disturbance can be reduced, and flapping of the support immediately before the application portion is effectively reduced.

  Further, according to a fifth aspect of the present invention, each of the plurality of guide rollers disposed between the application unit and the upstream third guide roller may have an eccentric amount of 100 μm or less.

  In this case, flapping of the support just before the application part is effectively suppressed. Note that “the plurality of guide rollers disposed between the application unit and the upstream third guide roller” herein includes “guide rollers in the application unit” and “upstream third guide roller”. included. Therefore, when a guide roller such as a backup roller (coating roller) is arranged in the application section, the “backup roller, upstream first guide roller, upstream second guide roller, and upstream third guide roller” It corresponds to “a plurality of guide rollers disposed between the application unit and the upstream third guide roller”. On the other hand, when a guide roller such as a backup roller is not disposed in the application unit, the “upstream first guide roller, upstream second guide roller, and upstream third guide roller” are “from the application unit to the upstream side. It corresponds to “the plurality of guide rollers disposed between the third guide rollers”.

  In order to achieve the above object, the invention according to claim 6 relates to an optical film characterized by having at least one coating layer obtained by the above-described coating solution coating method.

  According to the present invention, since a coating layer formed on a support that is conveyed in a stable state with reduced fluttering is used, a high-quality optical film is provided.

In order to achieve the object, the invention according to claim 7 is characterized in that a coating liquid is discharged from a slot die toward the surface of a support conveyed by a plurality of guide rollers, and the slot die, the support, And a coating liquid coating apparatus for forming a coating layer having a wet film thickness of 20 μm or less by laying a bead of the coating liquid between them and applying the coating liquid on the surface of the support with the bead. The coating liquid coating apparatus includes: an upstream first guide roller disposed first on the upstream side from a coating portion where the coating liquid is coated on the support by the slot die, and the upstream side of the guide roller. _A roll span LA with the guide roller adjacent to the downstream side with respect to the first guide roller, an upstream second guide roller and the upstream side of the guide roller that are secondly arranged upstream from the application section. A roll span L _B with the first guide roller, and a roll span L _C between the upstream third guide roller and the upstream second guide roller, which are arranged third from the application section to the upstream side among the guide rollers. Each satisfy 50 mm ≦ L _A ≦ 500 mm, 50 mm ≦ L _B ≦ 500 mm, and 50 mm ≦ L _c ≦ 500 mm.

  According to the coating liquid coating method and the coating apparatus of the present invention, the roll span of the guide roller on the upstream side of the coating unit is set to an appropriate range, and the flapping of the support in the vicinity of the coating unit is effectively reduced, A highly accurate coating layer can be formed on the support by the coating liquid discharged from the slot die.

  Moreover, since the optical film of this invention contains the coating layer formed by apply | coating a coating liquid on the support body by which flapping was suppressed, it has favorable quality.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings.

  FIG. 1 is a diagram showing an overall schematic configuration of a slot die coater type coating system 10. The arrows in the figure indicate the traveling direction of the web 14. In order to show the slot die coater type coating system 10 concisely, the detailed sizes and arrangement positions of the devices shown in FIG. 1 do not necessarily coincide with the actual devices. For example, with respect to the plurality of pass rollers 68 that convey the web 14, only the pass rollers 68 arranged at representative positions are shown.

  In the slot die coater type coating system 10 of the present embodiment, from the upstream side toward the downstream side, the feeder 66, the dust remover 74, the slot die 18 and the backup roller 12, the drying device 76, the heating device 78, and the ultraviolet irradiation device 80. , And a winder 82 are sequentially installed. Note that “upstream” and “downstream” here are based on the traveling direction of the web 14.

  The feeding machine 66 sequentially feeds the web 14 being wound up to the downstream side. The dust remover 74 removes foreign matters such as dust adhering to the web 14. Although details of the slot die 18 and the backup roller 12 will be described later, the slot die 18 discharges the coating liquid toward the web 14 conveyed and supported by the backup roller 12, and a coating film is formed on the web 14. The drying device 76 dries the coating film formed on the web 14. The heating device 78 heats the coating film on the web 14 to form a liquid crystal layer. The ultraviolet irradiation device 80 irradiates the liquid crystal layer of the coating film with ultraviolet rays using an ultraviolet lamp, and crosslinks the liquid crystal of the coating film to form a desired polymer. The winder 82 winds and collects the web 14 on which the polymerized coating film (coating layer) is laminated.

  A plurality of pass rollers 68 are provided between the devices of the slot die coater type coating system 10, and the web 14 is fed from the upstream side to the downstream side by these pass rollers 68. The position and number of the pass rollers 68, the distance between the rotation centers of the adjacent pass rollers 68 (hereinafter also referred to as “roll span”), and the like are appropriately adjusted as necessary.

  As described above, in the above-described slot die coater type coating system 10, the backup roller 12 and the pass roller 68 serve as guide rollers for conveying the web 14. In addition, the slot die coater type coating system 10 can introduce other devices as required. For example, a rubbing treatment device for adjusting the orientation of the liquid crystal part of the coating film is installed before and after the dust remover 74. It is also possible to do.

  Next, the backup roller 12, the slot die 18, and the pass rollers 68 around them will be described.

  In the present embodiment, the coating liquid is discharged from the slot die 18 toward the surface of the web 14, and a bead (not shown) of the coating liquid is installed between the slot die 18 and the web 14. Then, a bead coating solution is applied to the surface of the web 14 that runs continuously, and a coating film (coating layer) is formed on the web 14.

  FIG. 2 is a perspective view showing a state in which a part of the slot die 18 is cut.

  The slot die 18 has a manifold 22 provided inside the main body 50 and a slot 24 extending from the manifold 22 to the tip of the slot die 18. The slot die 18 includes two blocks, an upstream die block 18A and a downstream die block 18B. The manifold 22 and the slot 24 are part of the boundary between the upstream die block 18A and the downstream die block 18B. It has become. Thus, by making the slot die 18 have a multi-block structure, the manufacturing accuracy of the slot die 18 is increased and post-processing such as cleaning is facilitated. The specific shape and size of the slot die 18 are determined based on its own weight, the environment during use, the temperature of the coating liquid, the manufacturing specification limit, and the like.

  The tip end portion of the slot die 18 is formed in a tapered shape, and the tip end is called a lip land 16. The lip land 16 on the upstream side of the web of the slot 24 is referred to as an upstream lip land 16A, and the lip land 16 on the downstream side of the web is referred to as a downstream lip land 16B.

  The manifold 22 is a liquid reservoir that spreads the coating liquid supplied to the slot die 18 in the coating width direction (web width direction), and extends in the web width direction (longitudinal direction). The manifold 22 has a substantially circular cross-sectional shape, and forms a hollow portion having substantially the same cross-sectional shape along the web width direction. The effective length of the manifold 22 in the web width direction is set equal to or slightly longer than the coating width for the web 14. The manifold 22 is also referred to as “pocket” or “manifold”.

  Closing plates 54 are provided at both ends of the slot die 18 in the web width direction. One closing plate 54 is provided with a coating solution supply pipe 46 for supplying the coating solution to the manifold 22, and the other closing plate 54 is used for discharging the coating solution in the manifold 22 to the outside. The coating liquid discharge pipe 52 is provided so as to penetrate therethrough. The coating liquid is supplied from the coating liquid tank 48 to the manifold 22 through the coating liquid supply pipe 46, and unnecessary coating liquid in the manifold 22 is discharged to the outside through the coating liquid discharge pipe 52.

  The slot 24 constitutes a narrow flow path for the coating liquid from the manifold 22 to the tip of the slot, and discharges the coating liquid from the opening 24 A at the tip of the slot die 18, so that the slot 24 is between the slot die 18 and the web 14. The bead 20 is installed. The slot 24 usually has an opening width of about 0.01 to 0.5 mm, and has a length larger than the coating width of the coating liquid on the web 14 in the web width direction (longitudinal direction). The flow path length of the slot 24 extending from the manifold 22 toward the web 14 can be set in consideration of various conditions such as the liquid composition of the coating liquid, physical properties, supply flow rate, supply liquid pressure, and the like. It is preferable to set the flow path length of the slot 24 so that the coating liquid discharged from the opening 24A has a substantially uniform flow rate and fluid pressure in the web width direction.

  At both ends of the slot 24 in the web width direction, the width regulating plates 60 are inserted in contact with the upstream die block 18A and the downstream die block 18B that constitute the wall portion of the slot 24. The width regulating plate 60 is a member that regulates the coating width of the coating liquid discharged from the opening 24 </ b> A of the slot 24 of the slot die 18.

  FIG. 3 is a view showing an example of an arrangement relationship between the slot die 18 and the backup roller 12 and the peripheral pass rollers 68. In FIG. 3, the pass roller 68 disposed on the upstream side of the coating portion 84 where the coating liquid is applied onto the web 14 by the slot die 18, the pass roller (“upstream side” disposed first from the coating portion 84. 68A, second pass roller (also referred to as “upstream second pass roller”) 68B, and third pass roller (also referred to as “upstream third pass roller”) 68C. It is shown in the figure. In addition, the pass roller 68 disposed downstream of the application unit 84 where the coating liquid is applied onto the web 14 by the slot die 18 is the first pass roller (“downstream first pass roller” disposed from the application unit 84. ) 68D, the second pass roller (also referred to as “downstream second pass roller”) 68E, and the third pass roller (also referred to as “downstream third pass roller”) 68F are shown in FIG. Is shown in FIG.

  As a result of earnest research, the present inventor has obtained the following findings as suggested in [Examples] described below.

That is, in order to form a high-quality thin coating film on the web 14, it is very effective to suppress the fluttering of the web 14 in the coating portion 84. In particular, when a thin coating film having a wet film thickness of 20 μm or less is formed on the web 14, the upstream first pass roller 68 </ b> A and the upstream first pass roller disposed first on the upstream side from the coating unit 84. 68A, the roll span L _A with the backup roller 12 adjacent to the downstream side, the roll span L _B between the upstream second pass roller 68B and the upstream first pass roller 68A, and the upstream third pass roller 68C and the upstream side 2 pass roller 68B and roll span _{L C} of, so as to satisfy the following equation (1) to (3) is preferably disposed.

_{50mm ≦ L A ≦ 500mm (1} )
50mm ≤ L _B ≤ 500mm (2)
50mm ≦ _Lc ≦ 500mm (3)
Range to the roll span L _A represented by the above formulas (1) to _(3), L _B, by setting the L _C, flapping of the web 14 can provide a relatively large effect on the quality of the coating film Even when a thin coating film having a “wet film thickness of 20 μm or less” is formed, the web 14 is stably held and conveyed by the backup roller 12 and the pass roller 68, and the web 14 flutters in the coating unit 84. It can be effectively reduced. The pass roller 68 preferably has the same structure and diameter as possible.

  The wet film thickness is controlled by appropriately adjusting the coating speed (conveying speed of the web 14) and the coating amount of the coating liquid discharged from the slot die 18.

  In this case, the tension of the web 14 disposed between the upstream third pass roller 68C and the application unit 84 is preferably set to 150 N or more per 1 m width of the web 14. By setting the tension of the web 14 in such a range, the web 14 is conveyed in a tensioned state, and flapping in the application unit 84 can be effectively suppressed. The upper limit of the tension is determined according to the breaking strength of the web 14.

  In this case, it is preferable that the flutter of the web 14 in the middle between the upstream first pass roller 68A and the application unit 84 is less than 1 mm. As described above, the fluttering at the coating unit 84 is made less than 1 mm in the middle between the upstream first pass roller 68A and the coating unit 84, for example, in the middle between the upstream first pass roller 68A and the coating unit 84. Is effectively suppressed.

  Further, in this case, the component in the direction perpendicular to the film surface of the web 14 out of the wind speed of the wind sprayed on the web 14 disposed between the upstream third pass roller 68C and the application unit 84 is 2 m / s or less. It is preferable. By setting the wind speed of the wind blown to the web 14 in such a range, the wind force applied to the web 14 can be reduced, and the flapping of the web 14 in the application part 84 is effectively suppressed.

  In this case, the backup roller 12, the upstream first pass roller 68A, the upstream second pass roller 68B, and the upstream third pass roller 68C disposed between the coating unit 84 and the upstream third pass roller 68C are eccentric. The amount is preferably 100 μm or less. As described above, by reducing the amount of eccentricity of the backup roller 12 and the pass roller 68 disposed in the vicinity of the application unit 84, the flapping of the web 14 in the application unit 84 can be effectively reduced.

  The above-described matters exemplify one aspect of the present invention, and various modifications such as design changes can be added based on the knowledge of those skilled in the art, and known elements can be applied. Such various aspects can also be included in the scope of the present invention.

  For example, the web 14 and the coating liquid may include those containing various components according to the purpose. As an example, polyethylene terephthalate, polyethylene-2,6-naphthalate, cellulose diacetate, cellulose triacetate, cellulose acetate propionate, polyvinyl chloride, polyvinylidene chloride, polycarbonate, polyimide, polyamide and other known plastic films, paper, On the surface of a strip-shaped substrate such as various laminated papers coated with α-polyolefins having 2 to 10 carbon atoms, such as polyethylene, polypropylene, ethylene butene copolymer, etc. on paper, metal foils such as aluminum, copper, tin, etc. A material in which a preliminary processed layer is formed or various composite materials obtained by laminating them can be used as the material of the web 14.

  In addition, as a solvent for the coating solution, water, various halogenated hydrocarbons, alcohols, ethers, esters, ketones, or the like can be used alone or in combination.

  Also, as a coating solution, an optical compensation sheet coating solution, an antireflection film coating solution, an anti-glare coating liquid, a magnetic coating solution, a photographic photosensitive coating solution, a magnetic coating solution, a viewing angle widening coating solution, a surface protection solution, an antistatic solution A lubricating coating solution, a color filter pigment solution, or other optical functional film coating solution may be used. In particular, the above-described slot die coater type coating system 10 is effective when using a coating solution for an optical function film that requires the surface of the coating film to be formed with high accuracy.

  Further, the backup roller 12 and the slot die 18 in the slot die coater type coating system 10 may have any arrangement and configuration as long as the coating liquid can be appropriately coated on the web 14.

  Further, the supply method of the coating liquid to the manifold 22 may be any method as long as the coating liquid is appropriately supplied to the manifold 22. For example, not only the method of supplying the coating liquid from one end side of the manifold 22 (see FIG. 2), but also the method of supplying the coating liquid from the center of the manifold 22 and preventing the coating liquid from leaking to both ends of the manifold 22 A system may be used in which a new coating liquid is supplied from one end of the manifold 22 and a part of the coating liquid extracted from the other end is circulated again to the one end.

  The technique according to the present invention described above is effective when the properties of the coating film tend to become unstable, the wet film thickness of the coating film is 20 μm or less, particularly 15 μm or less, and the viscosity of the coating solution is 15 mPas or less. In particular, it is also effective in the case of 10 mPas or less.

In the above description, an example in which the backup roller 12 (guide roller) is disposed in the application unit 84 has been described. However, the present invention is not limited to the above-described embodiment. FIG. 4 is a view showing a modification of the arrangement relationship between the slot die 18 and the backup roller 12 and the peripheral pass rollers 68. As shown in FIG. 4, the above-described technique based on the present invention can be applied even when the backup roller 12 is not present. When the backup roller 12 is not present, the “guide roller adjacent to the upstream side first pass roller 68A on the downstream side” refers to the downstream side first pass roller 68D, and “the upstream side first pass roller 68A and the upstream side thereof”. The roll span L _A between the first pass roller 68A and the guide roller adjacent to the downstream side refers to the roll span between the upstream first pass roller 68A and the downstream first pass roller 68D.

  Although the Example in the above-mentioned coating system 10 is described below, this invention is not limited to a following example.

The coating solution used in each of the following examples was prepared as follows. That is, "MEK-ST (average particle size of 10 nm to 20 nm, solid content concentration of 30% by weight) with respect to 93 g of a 6% by weight methyl ethyl ketone solution (JN-7228, manufactured by JSR Corporation) of a thermally crosslinkable fluorine-containing polymer" SiO ₂ sol dispersed in methyl ethyl ketone of the Nissan chemical Co., Ltd.) 8 g "and, with the addition of" Methyl ethyl ketone 94g ", and" cyclohexanone 6g ", stir. And the solution prepared by filtering the stirred solution with a polypropylene filter (PPE-01) having a pore diameter of 1 μm was used as a coating solution. In addition, this coating liquid is used as a low refractive index layer coating liquid, and the refractive index is adjusted to 1.42. Moreover, the viscosity of the coating solution was 2 mPa, 15 mPa, and 17 mPa.

  On the other hand, a polyethylene terephthalate film (Lumirror, manufactured by Toray Industries, Inc.) having a width of 1000 mm was used as the web 14.

  Among the coating conditions of the following examples, the line speed (the conveyance speed of the web 14) is set to 20 m / min, and the wet film thickness of the coating film formed on the web 14 is set to 20 μm. Further, the roll span other than “between the application unit 84 and the upstream third pass roller 68C” is set in a range of 50 mm or more and 1000 mm or less, and in particular, the roll between the backup roller 12 and the downstream first pass roller 68D. Each of the span, the roll span between the downstream first pass roller 68D and the downstream second pass roller 68E, and the roll span between the downstream second pass roller 68E and the downstream third pass roller 68F is set to 500 mm. . The reason why the roll span is set to 50 mm or more is to suppress the strength and eccentricity of the roller in consideration of the original functions of the pass roller 68 and the backup roller 12 (guide roller) for stably transporting the web 14. This is because a roller diameter of 50 mm or more is considered necessary.

  The flutter of the web 14 is measured by placing a laser displacement meter (manufactured by Keyence Corporation, LT-8100) perpendicular to the web 14 and measuring the maximum and minimum displacements of the web 14 measured by the laser displacement meter. Made based on the difference. Unless otherwise noted, the flapping evaluation of the web 14 was performed based on the fluttering amount at an intermediate point (middle) between the backup roller 12 and the upstream first pass roller 68A immediately before the coating unit 84. .

Example 1
In the present example, the roll span of the pass roller 68 upstream of the coating portion 84 where the coating liquid is applied onto the web 14 by the slot die 18 and the viscosity of the coating liquid are changed to change the web 14 from the slot die 18. The coating liquid was discharged toward the surface. More specifically, the flapping of the web 14 was evaluated by changing the roll span between the backup roller 12 and the upstream first pass roller 68A to 100 mm, 300 mm, 500 mm, and 800 mm.

  Other application conditions are as follows. That is, the roll span between the upstream first pass roller 68A and the upstream second pass roller 68B was 300 mm, and the roll span between the upstream second pass roller 68B and the upstream third pass roller 68C was 200 mm. Further, the wind speed of the air blown perpendicularly to the film surface of the web 14 is 0.1 m / s, and the eccentricity of the backup roller 12, the upstream first pass roller 68A, the upstream second pass roller 68B, and the upstream third pass roller 68C. The amount was 10 μm or less. Further, the tension of the web 14 disposed between the application unit 84 and the upstream third pass roller 68C was set to 200N. Then, the amount of fluttering at an intermediate point between the backup roller 12 and the upstream first pass roller 68A was measured and evaluated.

  Table 1 below shows “the viscosity of the coating liquid (see“ viscosity ”in the table)” and “the roll span between the backup roller 12 and the upstream first pass roller 68A (see“ roll span ”in the table). “Fluctuation amount of the web 14 between the backup roller 12 and the upstream first pass roller 68A” (see “Fluctuation amount” in the table) ”and“ Step unevenness of the coating film formed on the web 14 ” (See “Step unevenness strength” in the table). In the following tables, “step unevenness strength” is a visual evaluation of step unevenness of the coating film on the web 14, “◎” is a level at which no step unevenness is visually recognized, and “◯”. Is a level where there is a slight unevenness, but there is no problem as a product, “△” is a level at which unevenness is clearly recognized in a part of the coating film, and “×” is a leveling unevenness over almost the entire coating film. It means a clearly recognized level.

表１に示されているように、塗布液の粘度が１５ｍＰａｓ以下の場合には、バックアップローラ１２と上流側第１パスローラ６８Ａの間のロールスパンを５００ｍｍ以下に調整することにより、上流側第１パスローラ６８Ａと塗布部８４との中間におけるウェブ１４のばたつきを１ｍｍ未満に低減させて、塗布膜の段ムラを抑えることができることが確認された。

As shown in Table 1, when the viscosity of the coating liquid is 15 mPas or less, the roll span between the backup roller 12 and the upstream first pass roller 68A is adjusted to 500 mm or less, whereby the upstream first It was confirmed that the flutter of the web 14 in the middle between the pass roller 68A and the coating part 84 can be reduced to less than 1 mm, and the unevenness of the coating film can be suppressed.

  In addition, when the viscosity of the coating liquid is higher than 15 mPas, even if the roll span between the backup roller 12 and the upstream first pass roller 68A is longer than 500 mm, a coating film with good quality with little step unevenness is provided. The This is considered to be because when the coating liquid becomes highly viscous, the stability of the bead 20 is improved and the coating film is not easily affected by the uneven feeding of the web 14.

(Example 2)
In this example, the tension of the web 14 disposed between the coating unit 84 and the upstream third pass roller 68C was changed, and the coating liquid was discharged from the slot die 18 toward the web 14. More specifically, the flapping of the web 14 was evaluated by changing the tension per 1 m of the web 14 disposed between the application unit 84 and the upstream third pass roller 68C to 100 N, 150 N, and 200 N. . In this example, the web 14 disposed between the coating unit 84 and the upstream third pass roller 68C is appropriately adjusted by appropriately adjusting the feeding force and winding force of the web 14 in the feeding machine 66 and the winding machine 82. Changed the tension.

  Other application conditions are as follows. That is, the velocity of the wind blown perpendicularly to the surface of the web 14 is 0.1 m / s, and the backup roller 12, the upstream first pass roller 68A, the upstream second pass roller 68B, and the upstream third pass roller 68C are eccentric. The amount was 10 μm or less. The roll span between the backup roller 12 and the upstream first pass roller 68A is 300 mm, the roll span between the upstream first pass roller 68A and the upstream second pass roller 68B is 300 mm, and the upstream second pass roller 68B The roll span between the upstream third pass roller 68C was 200 mm. The other application conditions were the same as those in Example 1 described above.

  Table 2 below shows “viscosity of coating solution” and “tension per 1 m width of the web 14 disposed between the coating unit 84 and the upstream third pass roller 68C (see“ tension ”in the table). The “fluctuation amount of the web 14” and the “step unevenness of the coating film on the web 14” when changed are shown.

表２に示されているように、塗布液の粘度が１５ｍＰａｓ以下の場合には、塗布部８４と上流側第３パスローラ６８Ｃとの間に配置されるウェブ１４の幅１ｍ当たりのテンションを１５０Ｎ以上に調整することで、上流側第１パスローラ６８Ａと塗布部８４との中間におけるウェブ１４のばたつきを１ｍｍ未満に低減させて、塗布膜の段ムラを効果的に解消することができることが確認された。なお、塗布液の粘度が１５ｍＰａｓよりも高い場合に塗布膜の段ムラが抑えられているのは、上述の実施例１において説明したように、高粘度の塗布液によってビード２０の安定性が向上し、ウェブ１４の送りムラの影響を塗布膜が受けにくいからであると考えられる。

As shown in Table 2, when the viscosity of the coating liquid is 15 mPas or less, the tension per 1 m width of the web 14 disposed between the coating unit 84 and the upstream third pass roller 68C is 150 N or more. It was confirmed that the fluttering of the web 14 in the middle between the upstream first pass roller 68A and the coating unit 84 can be reduced to less than 1 mm by adjusting the thickness of the coating film to effectively eliminate the unevenness of the coating film. . In addition, when the viscosity of the coating liquid is higher than 15 mPas, the unevenness of the coating film is suppressed, as described in Example 1 above, because the stability of the bead 20 is improved by the high-viscosity coating liquid. However, it is considered that the coating film is not easily affected by the feeding unevenness of the web 14.

(Example 3)
In this example, the wind speed of the wind blown against the film surface (surface) of the web 14 disposed between the coating unit 84 and the upstream third pass roller 68C is changed, and coating is performed from the slot die 18 toward the web 14. The liquid was discharged. More specifically, the wind speed was adjusted by adjusting the rotation speed and opening degree of the fan using a fan that adjusts the wind with respect to the web 14. The wind speed of the wind blown against the film surface of the web 14 was a value measured by Anemo Master (manufactured by Nippon Kanomax Co., Ltd.).

  Other application conditions are as follows. That is, the tension per 1 m of the width of the web 14 disposed between the coating unit 84 and the upstream third pass roller 68C is 200 N, the backup roller 12, the upstream first pass roller 68A, the upstream second pass roller 68B, The amount of eccentricity of the upstream third pass roller 68C was set to 10 μm or less. The roll span between the backup roller 12 and the upstream first pass roller 68A is 300 mm, the roll span between the upstream first pass roller 68A and the upstream second pass roller 68B is 300 mm, and the upstream second pass roller 68B The roll span between the upstream third pass roller 68C was 200 mm. The other application conditions were the same as those in Example 1 described above.

  Table 3 below shows the “coating on the web 14” when the “viscosity of the coating solution” and “the wind speed of the wind sprayed perpendicularly to the film surface of the web 14 (see“ wind speed ”in the table)” are changed. "Step unevenness of film" is shown.

表３に示されているように、塗布液の粘度が１５ｍＰａｓ以下の場合には、塗布部８４と上流側第３パスローラ６８Ｃとの間に配置されるウェブ１４の膜面に対して吹き付ける風の風速を２ｍ／ｓ以下に調整することで、ウェブ１４のばたつきを低減させて、塗布膜の段ムラを効果的に解消することができることが確認された。なお、塗布液の粘度が１５ｍＰａｓよりも高い場合に塗布膜の段ムラが抑えられているのは、上述の実施例１において説明したように、高粘度の塗布液によってビード２０の安定性が向上するからであると考えられる。

As shown in Table 3, when the viscosity of the coating solution is 15 mPas or less, the wind blown against the film surface of the web 14 disposed between the coating unit 84 and the upstream third pass roller 68C. It was confirmed that by adjusting the wind speed to 2 m / s or less, the flapping of the web 14 can be reduced and the unevenness of the coating film can be effectively eliminated. In addition, when the viscosity of the coating liquid is higher than 15 mPas, the unevenness of the coating film is suppressed, as described in Example 1 above, because the stability of the bead 20 is improved by the high-viscosity coating liquid. It is thought that it is because it does.

Example 4
In this example, the eccentric amounts of the backup roller 12, the upstream first pass roller 68A, the upstream second pass roller 68B, and the upstream third pass roller 68C disposed between the application unit 84 and the upstream third pass roller 68C are determined. Instead, the coating liquid was discharged from the slot die 18 toward the web 14. More specifically, the eccentric amounts of the backup roller 12, the upstream first pass roller 68A, the upstream second pass roller 68B, and the upstream third pass roller 68C were 10 μm, 100 μm, and 200 μm. The eccentric amount was adjusted by inserting (inserting) a shim into the bearing.

  Other application conditions are as follows. That is, with respect to the web 14 disposed between the application unit 84 and the upstream third pass roller 68C, the tension per 1 m width was 200 N, and the wind speed of the blown wind was 0.1 m / s. The roll span between the backup roller 12 and the upstream first pass roller 68A is 300 mm, the roll span between the upstream first pass roller 68A and the upstream second pass roller 68B is 300 mm, and the upstream second pass roller 68B The roll span between the upstream third pass roller 68C was 200 mm. The other application conditions were the same as those in Example 1 described above.

  Table 4 below shows the “viscosity of the coating solution” and “the eccentric amount of the backup roller 12 and the pass rollers 68A, 68B, 68C disposed between the coating unit 84 and the upstream third pass roller 68C (the“ pass roller in the table ”). “Eccentricity” (see “Eccentricity of coating film on web 14”) is changed.

表４に示されているように、塗布液の粘度が１５ｍＰａｓ以下の場合には、塗布部８４から上流側第３パスローラ６８Ｃまでの間に配置されるバックアップローラ１２およびパスローラ６８Ａ、６８Ｂ、６８Ｃの偏心量を１００μｍ以下に調整することで、ウェブ１４のばたつきを低減させて、塗布膜の段ムラを効果的に解消することができることが確認された。なお、塗布液の粘度が１５ｍＰａｓよりも高い場合に塗布膜の段ムラが抑えられているのは、上述の実施例１において説明したように、高粘度の塗布液によってビード２０の安定性が向上するからであると考えられる。

As shown in Table 4, when the viscosity of the coating solution is 15 mPas or less, the backup roller 12 and the pass rollers 68A, 68B, and 68C disposed between the coating unit 84 and the upstream third pass roller 68C. It was confirmed that by adjusting the amount of eccentricity to 100 μm or less, the flapping of the web 14 can be reduced and the unevenness of the coating film can be effectively eliminated. In addition, when the viscosity of the coating liquid is higher than 15 mPas, the unevenness of the coating film is suppressed, as described in Example 1 above, because the stability of the bead 20 is improved by the high-viscosity coating liquid. It is thought that it is because it does.

It is a figure which shows the schematic structure of the whole slot die-coater type coating system. It is a perspective view which shows the state which cut | disconnected some slot dies. It is a figure which shows an example of arrangement | positioning relationship with a slot die and a backup roller, and the pass roller of the periphery. It is a figure which shows one modification of the arrangement | positioning relationship between a slot die and a backup roller, and the pass roller of the periphery.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... Slot die coater type coating system, 12 ... Backup roller, 14 ... Web, 16 ... Lip land, 16A ... Upstream lip land, 16B ... Downstream lip land, 18 ... Slot die, 18A ... Upstream die block, 18B ... Downstream die block, 20 ... bead, 22 ... manifold, 24 ... slot, 24A ... opening, 46 ... coating liquid supply pipe, 50 ... main body, 52 ... coating liquid discharge pipe, 54 ... closure plate, 60 ... width regulating plate , 66 ... feeder, 68 ... pass roller, 68A ... upstream first pass roller, 68B ... upstream second pass roller, 68C ... upstream third pass roller, 68D ... downstream first pass roller, 68E ... downstream second pass roller, 68F ... downstream third pass roller, 74 ... dust remover, 76 ... drying device, 78 ... heating device, 80 ... ultraviolet irradiation device, 8 ... winding machine, 84 ... coating section

Claims (7)

A coating liquid is discharged from a slot die toward the surface of a support conveyed by a plurality of guide rollers, and a bead of the coating liquid is installed between the slot die and the support, and the support is supported by the beads. In the coating liquid coating method of coating the coating liquid on the surface of the coating film to form a coating layer having a wet film thickness of 20 μm or less,
Out of the guide rollers, an upstream first guide roller disposed first on the upstream side from the coating portion where the coating liquid is applied onto the support by the slot die, and downstream of the upstream first guide roller. Roll span L _A with the guide roller adjacent to the side, and roll span between the second guide roller upstream and the first guide roller upstream that is secondly arranged upstream from the coating portion of the guide rollers L _B, and each of the roll span L _C between the upstream side third guide roller and the upstream second guide roller disposed on the third upstream side from the coating section of said guide rollers,
50mm ≦ _{L A} ≦ 500mm
50mm ≦ L _B ≦ 500mm
50 mm ≦ L _c ≦ 500 mm
The coating method of the coating liquid characterized by satisfy | filling.   2. The coating liquid according to claim 1, wherein a tension of the support disposed between the upstream third guide roller and the coating unit is 150 N or more per 1 m of the width of the support. Application method.   3. The coating solution coating method according to claim 1, wherein a flutter of the support in the middle between the upstream first guide roller and the coating unit is less than 1 mm.   The component in the direction perpendicular to the film surface of the support is 2 m / s or less in the wind speed of the wind blown to the support disposed between the upstream third guide roller and the coating unit. The coating method of the coating liquid according to any one of claims 1 to 3.   5. The eccentric amount of each of the plurality of guide rollers disposed between the application unit and the upstream third guide roller is 100 μm or less. 6. Application method of coating solution.   An optical film comprising at least one coating layer obtained by the coating liquid coating method according to any one of claims 1 to 5. A coating liquid is discharged from a slot die toward the surface of a support conveyed by a plurality of guide rollers, and a bead of the coating liquid is installed between the slot die and the support, and the support is supported by the beads. In the coating liquid coating apparatus for coating the surface of the coating liquid to form a coating layer having a wet film thickness of 20 μm or less,
Out of the guide rollers, an upstream first guide roller disposed first on the upstream side from the coating portion where the coating liquid is applied onto the support by the slot die, and downstream of the upstream first guide roller. Roll span L _A with the guide roller adjacent to the side, and roll span between the second guide roller upstream and the first guide roller upstream that is secondly arranged upstream from the coating portion of the guide rollers L _B, and each of the roll span L _C between the upstream side third guide roller and the upstream second guide roller disposed on the third upstream side from the coating section of said guide rollers,
50mm ≦ _{L A} ≦ 500mm
50mm ≦ L _B ≦ 500mm
50 mm ≦ L _c ≦ 500 mm
A coating solution coating apparatus characterized by satisfying

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