JP2011125777A - Coating apparatus and method of manufacturing coating film product using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a coating apparatus which can effectively suppress the instability of a discharge speed and a discharge angle of a washing liquid discharged to a web ear when washing an aqueous alkaline solution of a web, and a method of manufacturing a coating film product using the coating apparatus. <P>SOLUTION: A slit 32 includes a spacer 54 where a part 54a parallel to a slit discharge port 32A and an inclined part 54b generating the discharge angle of the washing liquid at the slit discharge port 32A are formed at a position spaced by a predetermined distance X from a pocket 46. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention mainly relates to a coating apparatus that discharges cleaning water supplied to a pocket portion of a slot die to a web coated with an alkaline aqueous solution that travels from a slit discharge port through a slit and cleans the web.

  In recent years, liquid crystal display devices have been adopted in various fields as flat image display devices (FPDs). The liquid crystal display device is composed of a sheet material (optical film) having an optical function such as a liquid crystal cell, a polarizing plate, and an optical compensation sheet (retardation plate).

  The polarizing plate is generally composed of a polarizing film and two transparent protective films provided on both sides thereof. A polarizing film is generally obtained by impregnating polyvinyl alcohol with an aqueous solution of iodine or a dichroic dye and uniaxially stretching it. The optical compensation sheet has a function of improving the display quality of the liquid crystal display device by eliminating image coloring and widening the viewing angle, and is therefore used in various liquid crystal display devices.

  As a transparent support for polarizing plates and optical compensation sheets, it is typified by cellulose acetate film having excellent light transmittance, optical non-orientation, excellent physical and mechanical properties, and characteristics with little change in temperature and humidity. Cellulose ester film is employed.

  As an optical compensation sheet, an optical compensation sheet having an optically anisotropic layer formed of liquid crystalline molecules (particularly, discotic liquid crystalline molecules) on a transparent support instead of the conventionally used stretched birefringent film is used. It is proposed to use. This optically anisotropic layer is formed by aligning liquid crystalline molecules and fixing the alignment state. By using liquid crystal molecules, particularly discotic liquid crystal molecules, optical compensation sheets having various optical characteristics corresponding to various display modes of the liquid crystal cell can be produced.

  A polarizing film or an optically anisotropic layer is provided on a cellulose ester film, which is a transparent support, via an adhesive layer or an alignment film (usually polyvinyl alcohol), which is a means for providing adhesion to the adhesive layer and the alignment film. As one method, a method has been proposed in which a cellulose ester film is immersed in an alkaline aqueous solution to saponify and hydrophilize the surface (for example, Patent Document 1).

  In addition, a method of selectively saponifying one surface of the film by applying an alkaline aqueous solution to the cellulose ester film has been proposed (for example, Patent Document 2).

  Furthermore, a method of manufacturing an optical compensation sheet free from productivity and display defects by uniformly saponifying the entire surface has been proposed (Patent Document 3). Patent Document 3 discloses a saponification treatment process (heating, coating, saponification reaction, reaction stop, washing) using an alkaline aqueous solution. The saponification treatment process includes a wet / static charge / dust removal process, a heating process, and a coating process. Saponification reaction step, reaction stop step, and washing step.

  As a method for cleaning a web coated with an alkaline aqueous solution, a slot die is often used in which the cleaning liquid fed to the pocket portion in the coating head is pushed out through a slit communicating with the pocket portion and applied to the traveling web. ing.

JP 7-151914 A JP 2002-82226 A JP 2003-313326 A

  However, when cleaning the alkaline aqueous solution of the web with a slot die, it is impossible to suppress the failure of the ear due to the poor cleaning caused by the unstable discharge speed and discharge angle of the cleaning liquid discharged to the web ear. There are drawbacks.

  The present invention has been made in view of such circumstances, and effectively suppresses the instability of the discharge speed and discharge angle of the cleaning liquid discharged to the web ear when cleaning the alkaline aqueous solution of the web. It is an object of the present invention to provide a coating apparatus capable of forming a coating film and a method for producing a coated film product using the coating apparatus.

  In order to achieve the above object, the present invention provides a pocket portion that spreads in the web width direction where an alkaline aqueous solution that travels the cleaning liquid is applied, a liquid supply port that supplies the cleaning liquid to the pocket portion, and the cleaning liquid that is supplied to the pocket portion. A slit discharge port for discharging from the pocket to the web, and a slit through which the cleaning liquid passes from the pocket portion to the slit discharge port. Spacers are provided at both ends of the slit, and the spacer A portion parallel to the slit discharge port after a predetermined distance from the pocket portion and an inclined portion that forms a discharge angle at which the cleaning liquid inclines toward the central portion of the web at the slit discharge port are formed. And

  According to the present invention, when the cleaning water flows into the slit from the pocket portion, the discharge speed of the slit end can be increased by the portion parallel to the slit discharge port of the spacer, and by the inclined portion of the spacer, Since the discharge angle can be set so as not to go around to the back side of the web, it is possible to suppress the failure of the ear due to the cleaning failure due to the discharge speed of the cleaning liquid discharged to the web ear and the unstable discharge angle.

  The predetermined distance is preferably 3 mm or more. By being 3 mm or more, the discharge speed of the cleaning liquid to the web end can be preferably increased.

  In the spacer according to the present invention, it is preferable that a portion perpendicular to the slit discharge port is formed between the parallel portion and the inclined portion. Since the portion substantially perpendicular to the slit discharge port is formed, the discharge speed can be further increased, so that the failure of the ear due to poor cleaning can be further suppressed. In this specification, parallel or vertical is not limited to strictly parallel or vertical, but means within ± 20 ° from strictly parallel or vertical.

In the present invention, the discharge angle θ (°) of the cleaning liquid is related to the discharge speed v (m / s) at which the cleaning liquid is discharged from the slit discharge port so that θ <5.87v ² −16.0v + 27.2. A range that satisfies the above condition is preferable, and a range that satisfies θ ≦ 41.7 ln (v) −25.8 is more preferable. By setting it as this range, the failure of the ear | edge part by washing | cleaning failure can be suppressed.

  It is preferable to use a web that has been cleaned using the coating apparatus of the present invention as a coating film product because there are few failures at the end of the web. Moreover, it is preferable that this coating film product is an optical compensation film used for a liquid crystal display device.

  As described above, according to the coating apparatus of the present invention, it is possible to effectively suppress instability of the discharge speed and discharge angle of the cleaning liquid discharged to the web ear when cleaning the alkaline aqueous solution of the web. it can. Therefore, the coating film product manufactured using the coating apparatus of the present invention can provide a coating film product with few failures even at the web end.

Explanatory drawing explaining the production line of an optical compensation film Side sectional view of a coating apparatus according to the present invention Explanatory drawing explaining the coating device which concerns on this invention Explanatory drawing explaining another aspect of the coating device which concerns on this invention Table showing the results of experiments on spacers according to the present invention Graph showing experimental results

A case where a preferred embodiment of a coating apparatus according to the present invention is used in an optical compensation film production line will be described in detail below with reference to the accompanying drawings.
FIG. 1 is a diagram showing a production line of an optical compensation film, and each step until the optical compensation film is produced will be described in order.

[Production of alkali saponified polymer film]
As shown in FIG. 1, the method for producing an alkali saponified polymer film mainly includes an application step 20 in which an aqueous alkali solution is applied to the polymer film 16 fed from the feeder 66 to saponify the film surface, and the alkali saponified polymer film. 16 and a washing step 24 in which the alkaline aqueous solution is washed off and dried. In the present invention, in the coating step 20, the alkaline aqueous solution applied to the surface of the polymer film is circulated and used. The alkaline aqueous solution circulation line for circulating use will be described later.

In the coating process 20, an alkaline aqueous solution is applied to the polymer film 16 by the coating machine 22. As for the coating method, various modes can be adopted, but the coating amount of the alkaline aqueous solution is preferably suppressed as much as possible in consideration of waste liquid treatment for removal by washing with water, and is preferably 1 to 100 cc / m ² . 50 cc / m ² is more preferable. Therefore, a rod coater, a gravure coater, a blade coater, and a die coater that can be stably applied even in a small application amount range are particularly preferable. Moreover, it is preferable to apply the aqueous alkaline solution to the lower surface of the polymer film in order to easily wash off the aqueous alkaline solution after applying the aqueous alkaline solution and saponifying the polymer film.

  The alkali coating amount required for the saponification reaction is the total number of saponification sites obtained by multiplying the number of saponification reaction sites per unit area of the polymer film by the saponification depth necessary to develop adhesion with the alignment film (= theoretical alkali coating amount). ) Is a guide. As the saponification reaction proceeds, the alkali is consumed and the reaction rate decreases, so it is actually preferable to apply several times the theoretical alkali coating amount. Specifically, it is preferably 2 to 20 times the theoretical alkali coating amount, and more preferably 2 to 5 times.

  The temperature of the alkaline aqueous solution is desirably equal to the reaction temperature (= the temperature of the polymer film). Depending on the type of organic solvent used, the reaction temperature may exceed the boiling point of the alkaline aqueous solution. In order to perform stable coating, the temperature is preferably lower than the boiling point of the aqueous alkali solution, more preferably 5 ° C. lower than the boiling point, and most preferably 10 ° C. lower than the boiling point. .

  After applying the alkaline aqueous solution, it is preferable to keep the temperature of the polymer film at room temperature or higher until the saponification reaction is completed. The temperature of the polymer film may be the same as or different from the temperature heated before application of the alkaline aqueous solution. Further, the temperature may be changed continuously or stepwise during the saponification reaction. The film temperature is 15 to 150 ° C, preferably 25 to 100 ° C, more preferably 30 to 80 ° C.

  The time for which the aqueous alkaline solution is applied and kept in the temperature range before washing off depends on the conveying speed, but is preferably maintained for 1 to 300 seconds, more preferably 2 to 100 seconds, It is particularly preferred to keep it for 50 seconds.

  The polymer film saponified by applying an alkaline aqueous solution to the film surface in the coating step 22 is then washed in a washing step 24.

  Cleaning in the cleaning step 24 can be performed by a method of applying cleaning water, a method of spraying cleaning water, or a method of immersing the polymer film in a container containing cleaning water.

  The water spraying method can be generally performed by a method using a coating head (eg, fountain coater, frog mouth coater) or a method using a spray nozzle used for air humidification, painting, or automatic tank cleaning. .

  Here, in the present invention, an application apparatus (slot die) for discharging and cleaning the cleaning water supplied to the pocket portion through a slit to a polymer film (web) coated with an alkaline aqueous solution running from the slit discharge port. Is used.

  FIG. 2 shows a coating device 25 in the cleaning step 24 according to the present invention, and is a side sectional view in the case where pressure rollers 38 and 38 for pressing the web 16 against the coating head side are arranged on the upstream side and the downstream side of the coating device 25. FIG. As another aspect, a coating roller that engages and supports the web 16 may be disposed opposite the tip of the coating apparatus 10. Moreover, FIG. 3 is explanatory drawing explaining the principal part of this invention.

  The cleaning step 24 in FIG. 2 mainly includes a pair of a coating head that discharges the cleaning liquid from the slit discharge port 32A through the slit 32 and a web 16 that continuously travels in the direction of the arrow in close proximity to the tip of the coating apparatus 25. The pressing rollers 38, 38.

  The coating device 25 is composed of two blocks including a second edge portion 42 and a first edge portion 40, and the second edge portion 42 is located on the downstream side in the web traveling direction with the slit 32 as a boundary. The part 40 is located on the upstream side, and is disposed opposite to the web 16 in which the second edge part 42 and the first edge part 40 are in close proximity to each other.

  Inside the coating device 25, a cylindrical pocket portion 46 is formed along the width direction of the web 16 and communicated with the slit 32. Then, the cleaning liquid supplied to the pocket portion 46 is spread to a width corresponding to the coating width, and then rises up the slit 32 and is discharged from the slit discharge port 32A to clean the web 16 (see FIG. 3).

  As shown in FIG. 3A, a pocket stopper 48 is provided in the opening through which the pocket 46 passes. The other side of the pocket stopper 48 is provided with a liquid supply port 49 for side supply of the cleaning liquid, and the liquid supply pipe 50 is connected to the liquid supply port 49 to supply the cleaning liquid to the pocket portion 46. The liquid supply line for supplying the coating liquid to the liquid supply pipe 50 may be any line that can supply the cleaning liquid to the pocket portion 46 continuously and in a constant liquid amount.

  The slit 32 is a narrow flow path that connects the pocket portion 46 and the slit discharge port 32A, and extends in the web width direction. The flow path length of the slit 32 in the direction of the slit discharge port 32A is appropriately set in consideration of application conditions such as the liquid composition, physical properties, supply flow rate, and supply liquid pressure of the cleaning liquid.

  The coating device 25 formed in this way has a drawback in that it is not possible to suppress the failure of the ear due to poor cleaning caused by the instability of the discharge speed and discharge angle of the cleaning liquid discharged to the web ear. .

  Therefore, in the present invention, as shown in FIG. 3A, after a predetermined distance X from the pocket portion 46 to the slit 32, the portion 54a parallel to the slit discharge port 32A and the discharge angle of the cleaning liquid at the slit discharge port are set. The spacer 54 in which the inclined part 54b to be generated is formed is provided. Note that FIG. 3B is a cross-sectional view of a main part of the coating apparatus 25 of FIG.

  By providing such spacers 54 at both ends, when the cleaning water flows into the slit 32 from the pocket 46, the portion 54a parallel to the slit discharge port of the spacer 54 causes the slit end of the slit discharge port 32A. The discharge speed of the cleaning liquid can be increased, and the discharge angle of the cleaning liquid can be set so as not to go around the back of the web by the inclined portion 54b of the spacer. Ear failure due to poor cleaning due to instability can be suppressed.

  The predetermined distance X is preferably 3 mm or more. By being 3 mm or more, the discharge speed of the cleaning liquid to the web end can be preferably increased.

  Here, the portion 54a of the spacer 54 parallel to the slit discharge port 32A is formed to be less than 30 ° with respect to the slit discharge port 32A.

  Here, between the parallel portion 54a and the inclined portion 54b of the spacer 54 in FIG. 3A according to the present invention, a portion 54c substantially perpendicular to the slit discharge port 32A is formed as shown in FIG. It is preferable.

Since the portion 54c that is substantially perpendicular to the slit discharge port is formed, the discharge speed can be further increased, so that the failure of the ear due to poor cleaning can be further suppressed.
FIG. 5 is a table showing the results when the experiment was performed by varying the values of L1, L2, and θ1 of the spacer 54 of the coating apparatus 25 of FIG. In this experiment, the predetermined distance X shown in FIG. 3A was 3 mm.

  The discharge speed v and discharge angle θ of the cleaning water in this experiment are also shown in the table of FIG.

  FIG. 6 is a graph in which the results of the table of FIG. 5 are plotted with the discharge speed v on the horizontal axis and the discharge angle θ on the vertical axis. Here, “LL printing” refers to a state of a bright spot having a large size, and “white spot failure” refers to a state of low brightness of the bright spot. In addition, the evaluation is described as ◯ when the improvement effect is seen, △ when the improvement effect is small, and × when there is no improvement effect.

In the present invention, the discharge angle θ (°) of the cleaning liquid is related to the discharge speed v (m / s) at which the cleaning liquid is discharged from the slit discharge port so that θ <5.87v ² −16.0v + 27.2. It is found that the range is preferably satisfied, and it is further preferable that the range satisfies θ ≦ 41.7ln (v) −25.8. By setting it as this range, the failure of the ear | edge part by washing | cleaning failure can be suppressed. The above equation is an equation obtained by approximating the plotted points by the least square method.

  It is preferable to use pure water as the washing water. The pure water used in the present invention has a specific electric resistance of at least 0.1 MΩ or more, in particular, metal ions such as sodium, potassium, magnesium and calcium are less than 1 ppm, and anions such as chloro and nitric acid are less than 0.1 ppm. Preferably there is.

  The higher the washing water temperature, the higher the washing ability. However, in the method of spraying water on the polymer film to be transported, the area of water in contact with the air is large, and the evaporation becomes more significant as the temperature increases, so that the surrounding humidity increases and the risk of condensation is increased. For this reason, the temperature of the washing water is usually set in the range of 5 to 90 ° C, preferably 25 to 80 ° C, more preferably 25 to 60 ° C.

  If the components of the alkaline aqueous solution or the product of the saponification reaction are not easily dissolved in water, a solvent washing step for removing water-insoluble components may be added before or after the washing step. The solvent washing step can utilize the water washing method and draining means described above.

  A drying step (not shown) may be provided after the cleaning step 24. Usually, the water film can be sufficiently removed by a draining means such as an air knife, and a drying process may not be necessary. However, before winding the polymer film into a roll, it is dried by heating to adjust the moisture content to a preferred level. May be. Conversely, the humidity can be adjusted with a wind having a set humidity. The temperature of the drying air is preferably 30 to 200 ° C, more preferably 40 to 150 ° C, and particularly preferably 50 to 120 ° C.

  In the present invention, the aqueous alkaline solution used for the alkaline saponification is preferably an aqueous alkaline solution having a pH of 11 or more. More preferably, the pH is 12-14.

  Examples of the alkaline agent used in the alkaline aqueous solution include inorganic alkaline agents such as sodium hydroxide, potassium hydroxide and lithium hydroxide, diethanolamine, triethanolamine, DBU (1,8-diazabicyclo [5,4,0]. -7-undecene), DBN (1,5-diazabicyclo [4,3,0] -5-nonene), tetramethylammonium hydroxide, tetraethylammonium hydroxide, tetrapropylammonium hydroxide, tetrabutylammonium hydroxide, triethyl Organic alkali agents such as butylammonium hydroxide are also used. These alkaline agents can be used alone or in combination of two or more, and a part thereof may be added in the form of a salt, for example, halogenated.

  The concentration of the alkaline agent in the aqueous alkaline solution is determined according to the type of alkaline agent to be used, the reaction temperature and the reaction time. The content of the alkaline agent is such that the hydroxide ion concentration in the aqueous alkaline solution is 0.1 to 5 mol. / Kg is preferable, and 0.3 to 3 mol / kg is more preferable.

  The solvent of the alkaline aqueous solution is preferably a mixed solution of water and an alcohol which is a water-soluble organic solvent. As the organic solvent, those having a boiling point of 120 ° C. or lower, more preferably 60 to 120 ° C., particularly 60 to 100 ° C. are preferable.

[Formation of alignment film]
As shown in FIG. 1, the polymer film saponified as described above is coated with a coating solution containing an alignment film forming resin by a coating device 26, and dried by a drying device 28. A layer is formed.

  The alignment film is more preferably composed of two kinds of crosslinked polymers. One of the two polymers is a polymer that is itself crosslinkable or a polymer that is crosslinked by a crosslinking agent. The alignment film is formed by reacting a polymer having a functional group or a polymer into which a functional group is introduced by light, heat, or pH change between the polymers, or a cross-linking agent that is a highly reactive compound. It can be formed by introducing a linking group derived from a crosslinking agent between the polymers and crosslinking between the polymers.

  Crosslinking of the polymer can be carried out by applying a coating liquid containing a polymer or a mixture of a polymer and a crosslinking agent on the polymer film and then heating. You may perform the process made to bridge | crosslink in any step after coating an alignment film on a polymer film until it obtains an optical film. In consideration of the orientation of the compound having a discotic structure (optically anisotropic layer) formed on the alignment film, it is also preferable to carry out final crosslinking after orienting the compound having a discotic structure. That is, when a coating solution containing a polymer and a crosslinking agent capable of cross-linking the polymer is applied on the polymer film, after heating and drying, a rubbing treatment is performed to form an alignment film, and then a disk shape is formed on the alignment film. A coating liquid containing a compound having a structural unit is applied, heated to a temperature above the discotic nematic phase formation temperature, and then cooled to form an optically anisotropic layer.

  As the polymer used in the alignment film, either a polymer that can be crosslinked by itself or a polymer that is crosslinked by a crosslinking agent can be used, and a plurality of combinations thereof can be used. Examples of polymers include polymethyl methacrylate, acrylic acid / methacrylic acid copolymer, styrene / maleimide copolymer, polyvinyl alcohol and modified polyvinyl alcohol, poly (N-methylol acrylamide), styrene / vinyl toluene copolymer, Polymers such as chlorosulfonated polyethylene, nitrocellulose, polyvinyl chloride, chlorinated polyolefin, polyester, polyimide, vinyl acetate / vinyl chloride copolymer, ethylene / vinyl acetate copolymer, carboxymethyl cellulose, gelatin, polyethylene, polypropylene and polycarbonate And compounds such as silane coupling agents. Examples of preferred polymers are water-soluble polymers such as poly (N-methylolacrylamide), carboxymethylcellulose, gelatin, polyvir alcohol and modified polyvinyl alcohol, and gelatin, polyvir alcohol and modified polyvinyl alcohol are preferred. Alcohol and modified polyvinyl alcohol are particularly preferable, and it is particularly preferable to use two types of polyvinyl alcohol or modified polyvinyl alcohol having different degrees of polymerization.

  The saponification degree of polyvinyl alcohol is preferably 70 to 100%, more preferably 80 to 100%, and most preferably 85 to 95%. The polymerization degree of polyvinyl alcohol is preferably 100 to 3000. The modifying group of the modified polyvinyl alcohol can be introduced by copolymerization modification, chain transfer modification or block polymerization modification.

  Among these, unmodified polyvinyl alcohol or alkylthio-modified polyvinyl alcohol having a saponification degree of 85 to 95% is most preferable.

  Examples of cross-linking agents for polymers (preferably water-soluble polymers, more preferably polyvinyl alcohol or modified polyvinyl alcohol) include aldehydes (eg, formaldehyde, glyoxal, glutaraldehyde), N-methylol compounds (eg, dimethylol urea, methylol dimethyl). Hydantoin), dioxane derivatives (eg, 2,3-dihydroxydioxane), compounds acting by activating the carboxyl group (eg, carbenium, 2-naphthalenesulfonate, 1,1-bispyrrolidino-1-chloropyridinium, 1 -Morpholinocarbonyl-3- (sulfonatoaminomethyl)), active vinyl compounds (eg 1,3,5-triacroyl-hexahydro-s-triazine, bis (vinylsulfone) methane, N'-methylenebis- [ - (vinylsulfonyl) propionamide]), active halogen compounds (e.g., 2,4-dichloro-6-hydroxy -S- triazine), isooxazoles acids and dialdehyde starch. Two or more kinds of crosslinking agents may be used in combination. Aldehydes having high reaction activity, particularly glutaraldehyde are preferred.

  0.1-20 mass% is preferable with respect to a polymer, and, as for the addition amount of a crosslinking agent, 0.5-15 mass% is preferable. The amount of the unreacted crosslinking agent remaining in the alignment film is preferably 1.0% by mass or less, and more preferably 0.5% by mass or less. If the crosslinking agent remains in the alignment film in an amount exceeding 1.0% by mass, sufficient durability cannot be obtained. When such an alignment film is used in a liquid crystal display device, reticulation may occur when used for a long time or when left in a high temperature and high humidity atmosphere for a long time.

  The alignment film can be basically formed by applying the above polymer containing a crosslinking agent, which is an alignment film forming material, onto a polymer film, followed by drying by heating (crosslinking) and rubbing treatment. As described above, the cross-linking reaction may be performed at any time after coating on the polymer film. When a water-soluble polymer such as polyvinyl alcohol is used as the alignment film forming material, the coating solution is preferably a mixed solvent of an organic solvent (eg, methanol) having a defoaming action and water. The ratio of water: methanol is preferably 0: 100 to 99: 1, and more preferably 0: 100 to 91: 9. Thereby, generation | occurrence | production of a bubble is suppressed and the defect of the surface of an alignment film and also an optically anisotropic layer reduces remarkably.

  The alignment film is preferably applied by spin coating, dip coating, curtain coating, extrusion coating, rod coating, or roll coating. A rod coating method is particularly preferable. The film thickness after drying is preferably 0.1 to 10 μm. Heating and drying can be performed at 20 ° C to 110 ° C. In order to form sufficient cross-linking, 60 ° C to 100 ° C is preferable, and 80 ° C to 100 ° C is particularly preferable. The drying time can be 1 minute to 36 hours, preferably 1 minute to 30 minutes. The pH is preferably set to an optimum value for the crosslinking agent to be used. When glutaraldehyde is used, the pH is 4.5 to 5.5, and 5 is particularly preferable.

  The alignment film is provided on the polymer film. The alignment film can be obtained by crosslinking the polymer layer as described above and then rubbing the surface with the rubbing treatment device 70. Thereby, an alignment film is formed on the transparent resin layer. The alignment film is provided in order to define the alignment direction of the liquid crystalline discotic compound provided thereon.

  For the rubbing treatment, a treatment method widely adopted as a liquid crystal alignment treatment process of the LCD can be applied. That is, a method of obtaining the orientation by rubbing the surface of the orientation film in a certain direction using paper, gauze, felt, rubber, nylon, polyester fiber or the like can be used. Generally, it is carried out by rubbing several times using a cloth or the like in which fibers having a uniform length and thickness are planted on average.

  In the rubbing treatment device 70, the rubbing rolls 72, 72 are disposed between two transport rolls in the continuous transport process of the polymer film 16, and the polymer film 16 is wrapped while rotating the rubbing rolls 72, 72. It is preferable to continuously rub the surface of the polymer film 16 by conveying the film 16. In this case, it is also possible to arrange the rubbing rolls 72 and 72 with the rotation axis inclined with respect to the transport direction of the polymer film 16. The roundness, cylindricity, and runout of the rubbing roll 72 itself are preferably 30 μm or less. In the apparatus using the rubbing method described above, it is preferable that one or more spare rubbing rolls are provided in the apparatus. The dust attached to the surface of the polymer film 16 is removed by the dust remover 74.

[Formation of optically anisotropic layer]
The optically anisotropic layer of the optical compensation film is formed on the alignment film.

  A gravure coating device 75 applies a coating liquid (liquid crystal compound solution) containing a liquid crystal disconematic compound onto the alignment film layer of the polymer film 16. A liquid crystal discotic compound having a crosslinkable functional group is used as the liquid crystal discotic compound.

  The gravure coating device 75 is provided with a liquid receiving pan 14 below the gravure roller 12, and the liquid receiving pan 14 is filled with a coating liquid. The lower half of the gravure roller 12 is immersed in the coating solution. With this configuration, the coating liquid is supplied to the cells on the surface of the gravure roller 12. The upstream guide roller 17 and the downstream guide roller 18 are supported in parallel with the gravure roller 12. The upstream guide roller 17 and the downstream guide roller 18 are preferably configured such that both end portions are rotatably supported by bearing members (ball bearings or the like) and no drive mechanism is attached. The gravure coating device 75 may be installed in a clean atmosphere such as a clean room. At that time, the cleanliness is preferably class 1000 or less, more preferably class 100 or less, and still more preferably class 10 or less.

  In addition, although shown in the example of the gravure coating apparatus 75 as a coating device, it is not limited to this. For example, methods such as a dip coating method, an air knife coating method, a curtain coating method, a roller coating method, a wire bar coating method, a micro gravure method, and an extrusion coating method can be used as appropriate.

  Next, the polymer film 16 on which the coating film is formed by coating the coating liquid is dried by the drying device 76. In this case, within 3 seconds after the polymer film 16 passes through the gravure coating device 75 (more precisely, the gravure roller 12), or when the coating liquid is applied after the polymer film 16 passes through the gravure coating device 75. It is preferable that the organic solvent is introduced into the drying device 76 within a short time until the content of the organic solvent is less than 50% (more preferably less than 70%).

  In the drying device 76, the viscosity of the coating film becomes 10 mPa · s or more until the concentration of the organic solvent component in the coating film is reduced to 50% or less (half or less) of the concentration of the organic solvent component during coating. It is preferable to dry up to whichever is earlier.

  Next, the polymer film 16 that has been dried by the drying device 76 is passed through the latter-stage drying zone 77, the heating zone 78, and the ultraviolet lamp 80 in FIG. As a result, the coated layer of the dried polymer film 16 is heated to form a liquid crystal layer in a discotic nematic phase, and the liquid crystal layer is continuously irradiated with light to cure the discotic liquid crystal. In this case, it is preferable to heat the heating zone 78 by applying hot air or far-infrared rays or bringing a heating roller into contact with the side of the polymer film 16 that does not have the liquid crystal layer. Or it is preferable to carry out by giving a hot air or a far infrared ray to both surfaces of the polymer film 16. FIG. Then, the polymer film on which the alignment film and the liquid crystal layer are formed is wound around the winder 82.

  The preferred embodiment of the coating apparatus according to the present invention has been described above for use in the optical compensation film production line. However, the coating apparatus according to the present invention is a web coated with an alkaline aqueous solution in addition to the production of the optical compensation film. It can be suitably used also when washing.

  DESCRIPTION OF SYMBOLS 10 ... Production line, 12 ... Gravure roller, 13 ... Backup roller, 14 ... Liquid receiving pan, 16 ... Polymer film (web), 20 ... Application process, 22 ... Application machine, 24 ... Cleaning process, 25 ... Application apparatus, 26 Application device, 28 ... Drying device, 32 ... Slit, 46 ... Pocket, 48 ... Pocket stopper, 54 ... Spacer, 68 ... Guide roller, 70 ... Rubbing treatment device, 72 ... Rubbing roller, 74 ... Dust remover, 75 ... coating device, 76 ... drying device, 77 ... latter-stage drying device, 78 ... heating device, 80 ... ultraviolet lamp, 82 ... winder

Claims (7)

A pocket portion extending in a web width direction in which an alkaline aqueous solution that travels the cleaning liquid is applied; a liquid supply port that supplies the cleaning liquid to the pocket portion; a slit discharge port that discharges the cleaning liquid from the pocket portion to the web; A slit through which the cleaning liquid passes from the pocket portion to the slit outlet,
Spacers are provided at both ends of the slit,
The spacer includes
After a predetermined distance from the pocket portion, a portion parallel to the slit outlet,
An inclined portion that produces a discharge angle at which the cleaning liquid is inclined toward the center of the web at the slit discharge port;
An applicator characterized in that is formed.   The coating apparatus according to claim 1, wherein the predetermined distance is 3 mm or more.   The coating apparatus according to claim 1, wherein a portion perpendicular to the slit discharge port is formed between the parallel portion and the inclined portion. The discharge angle θ (°) of the cleaning liquid is set such that the relationship with the discharge speed v (m / s) at which the cleaning liquid is discharged from the slit discharge port satisfies θ <5.87v ² −16.0v + 27.2. The coating apparatus according to any one of claims 1 to 3, wherein:   The discharge angle θ (°) of the cleaning liquid is set such that the relationship with the discharge speed v (m / s) at which the cleaning liquid is discharged from the slit discharge port satisfies θ ≦ 41.7 ln (v) −25.8. The coating apparatus according to claim 4.   6. A method for producing a coated film product, wherein the web cleaned using the coating apparatus according to claim 1 is used as a coated film product.   The method for producing a coated film product according to claim 6, wherein the coated film product is an optical compensation film used in a liquid crystal display device.

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