KR20090029636A - Bar coating device, coating method using the same and method of manufacturing optical film - Google Patents

Abstract

A bar coating device is provided to prevent the generation of smudge on the vertical line of the coating surface and to perform uniform coating. A bar coating device comprises a bar(20), support member(22), upstream side girder member and downstream side girder member(30). The bar applies the coating solution to a strip-like body(18). The support member is installed at the bottom side of the bar and holds the bar rotatably. The upstream side girder member and downstream side girder member are installed at the upstream side and the downstream side respectively of moving direction and supplies the coating solution between the supporting members.

Description

Bar coating apparatus, coating method using bar coating apparatus, and manufacturing method of optical film {BAR COATING DEVICE, COATING METHOD USING THE SAME AND METHOD OF MANUFACTURING OPTICAL FILM}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a bar coating apparatus, a coating method using a bar coating apparatus, and a manufacturing method of an optical film, and more particularly, to a coating technique for producing an optical film having a desirable quality for a liquid crystal display device.

Application | coating in manufacture of optical functional films, such as an optical compensation film, is required to apply | coat and form a coating liquid uniformly and thinly. However, in such thin layer coating, coating defects such as streaks and scratches are often generated, and various countermeasures have been studied conventionally.

For example, in a blade coater, a method of applying a shear force to the coating liquid to reduce the viscosity before spraying the coating liquid from the fountain nozzle (Patent Document 1), and in the rod coater, foreign matters or aggregates caught in the grooves between the wires of the rod. A method (patent document 2) etc. which install the foreign material removal brush etc. for removal in a rod bar holder are proposed. In addition, after forming a coating film on a support body, in the application | coating method of scraping excess liquid with a scraping roller and obtaining a required film thickness, in order to suppress coating failure resulting from drying of the scraping roller surface, The method of supplying a coating liquid or a solvent is proposed (patent document 3).

In addition, in the bar application device, the relationship between the maximum radius of the cross section of the bar and the arc radius of curvature of the cross section of the bar receiving portion, the bar holding angle, and the like are applied to the bubbles generated between the stepped coating stains and the bar supporting members due to the bar vibration. It is proposed to prevent the coating line failure by this (patent document 4).

Moreover, it is proposed to arrange | position a beam in the upstream side of a support conveyance direction with respect to the contact part of an application bar, to comprise a liquid storage part between a contact part and a beam, and to overflow a part of coating liquid from a beam (patent document 5). Thereby, generation | occurrence | production of the application | coating line which arises by making regular vortex generate | occur | produce in the liquid storage part of a primary side (upstream side of a support conveyance direction with respect to the contact part of a coating bar) when raising an application | coating speed is suppressed.

[Patent Document 1] Japanese Patent Application Laid-Open No. 7-189196

[Patent Document 2] Japanese Patent Application Laid-Open No. 7-246358

[Patent Document 3] Japanese Patent Application Laid-Open No. 9-294956

[Patent Document 4] Japanese Patent Application Laid-Open No. 2006-82059

[Patent Document 5] Japanese Unexamined Patent Publication No. 2003-33702

By the way, in the bar application like patent documents 4 and 5, as shown in the conventional figure of FIG. 8, in order to prevent the coating failure by drying of the bar 2, the bar support member 3 which supports the bar 2 is carried out. The beam member 4 is provided also in the web traveling direction downstream (henceforth a secondary side) through this, and the slit 5 which supplies the coating liquid 8 is formed. Then, the coating liquid is supplied from the slit 5 to form a coating liquid bead between the bar surface, and the excess coating liquid overflows the upper surface 4A of the beam member 4 and is discharged.

However, when the rotational speed of the bar 2 is increased, the coating liquid supplied for preventing drying of the bar 2 and the surplus coating liquid flowing down the bar surface rapidly merge in the liquid storage part 6 at the outlet of the slit on the secondary side. As a result, disturbances such as vortex are generated in the coating liquid (see arrows). The disturbance of the coating liquid at the confluence point causes a concentration distribution to occur in the volatile gas volatilized from the coating liquid by further amplifying the coating liquid in the process of overflowing the beam member 4. Thereby, there existed a problem that the vertical line unevenness generate | occur | produced on the application surface 7A of the web 7. As shown in FIG.

On the other hand, in the said conventional method, not all the stain resulting from the volatile gas concentration distribution after coating was solved.

This invention is made | formed in view of such a situation, and an object of this invention is to provide the coating | coating apparatus and the manufacturing method using the same which can perform homogeneous application | coating, and a uniform line etc. do not generate | occur | produce in a coating surface immediately after application | coating. .

Claim 1 of this invention apply | coats a coating liquid to the strip | belt-shaped body which travels in order to achieve the said objective, It is provided in the lower side of the bar, The support member which rotatably supports the said bar, and the strip | belt-shaped body through the said support member. It is provided adjacent each upstream and downstream of a travel direction, and is provided with the upstream beam member and downstream beam member which form the slit which respectively supplies a coating liquid between the said support member, and the said downstream beam member is The inclined angle of the inclined surface facing the band-like body is 5 to 30 degrees to provide a bar coating device.

According to claim 1, the inclination angle of the slope of the downstream beam member is set to 5 to 30 degrees even when the coating liquid is disturbed near the slit outlet on the secondary side of the bar, so that the coating liquid is uniform on the slope of the downstream beam member. Can shed. For this reason, in the process in which the coating liquid overflows the downstream beam member, the vertical line unevenness is generated on the coated surface of the strip-shaped body without generating a concentration distribution by the volatile gas between the downstream beam member and the coated surface of the band-like body. Can be suppressed. Moreover, it is preferable to make the inclination angle of the slope of a downstream beam member 20 to 30 degree.

2. The coating according to claim 1, wherein the coating liquid has a viscosity of η (cp), a density of ρ (kg / m 3), a gravitational acceleration of g (kgf / sec), and flows on a slope of the downstream beam member. When the flow rate of the liquid is q (m 3 / sec) and the inclination angle is α (°), the inclination angle α of the slope of the downstream beam member is set to satisfy the following formula (1).

sin α ≧ 3 · η · q / {ρ · g · (4 × 10 ⁻⁴ ) ³ }. (Equation 1)

According to claim 2, since the inclination angle of the slope of the downstream beam member is set to satisfy the above formula 1, the coating liquid flows through the slope of the downstream beam member in a more uniform thin film form. Thereby, generation | occurrence | production of the vertical line | surface line can be suppressed in the application surface which opposes the slope of the downstream side beam member.

Claim 3 or 2 WHEREIN: It is characterized by making the said inclination-angle in the range of at least 10-80 mm from the side near the said slit among the slopes of the said downstream side beam member.

Thus, by setting the range of at least 10 to 80 mm from the side close to the slit to the inclination angle, disturbance of the volatile gas in a region where the separation distance from the coating film is small and the influence of volatile gas is large can be minimized. . Moreover, it is more preferable to make the said inclination angle the range of 15-40 mm at least from a slit side.

The horizontal separation distance of the apex of the said bar support member and the apex of the said downstream beam member is 1 mm or more, The Claim 4 in any one of Claims 1-3 characterized by the above-mentioned.

If the horizontal separation distance between the apex of the bar support member and the apex of the downstream beam member is too close to less than 1 mm, when a plurality of coating liquids are vigorously joined in the vicinity of the slit outlet on the secondary side, the coating liquid is disturbed. It becomes easy to occur. According to claim 4, since the horizontal separation distance between the apex of the bar support member and the apex of the downstream beam member is 1 mm or more, variance such as vortex occurs due to collision between coating liquids near the slit outlet on the secondary side. Can be suppressed.

Claim 5 is characterized in that the vertex of the downstream beam member is lower than the vertex of the bar support member.

According to claim 5, since the peak of the downstream beam member is lower than the peak of the bar support member, the excess coating liquid flowing from the bar surface to the secondary side is prevented from remaining in the vicinity of the slit outlet on the secondary side and is disturbed. The surface can overflow smoothly.

Claim 6 of this invention provides the application | coating method characterized by apply | coating a coating liquid to the strip | belt-shaped body which runs using the coating device as described in any one of Claims 1-5 in order to achieve the said objective.

According to claim 6, since the coating liquid does not generate the concentration distribution by the volatile gas between the coating liquid and the coating surface in the process of overflowing the downstream beam member, it is possible to suppress the occurrence of vertical line unevenness on the coating surface of the web.

Claim 7 is characterized in that the separation distance between the apex of the said downstream beam member and the surface of the said strip | belt-shaped body is 2 mm or less, It is characterized by the above-mentioned.

Thus, by making the separation distance of the slope of a downstream side beam member and the surface of a strip | belt-shaped object close to 2 mm or less, it becomes easy to liquid seal between a bar accommodating member and a downstream beam member. As a result, drying of the bar surface can be prevented, and mixing of bubbles can be prevented between the bar and the bar receiving member. On the other hand, when the space | interval of the slope of the downstream side beam member and the application | coating surface of a strip | belt-shaped object is so narrow, it becomes easy to generate | occur | produce a vertical line-shaped unevenness | corrugation on an application surface by the disturbance of the flow of a coating liquid. In such a case, by applying the present invention, it is possible to suppress occurrence of vertical line irregularities on the coated surface due to the disturbance of the coating liquid.

In order to achieve the above object, claim 8 of the present invention applies a coating liquid containing a liquid crystalline discotic compound on a band-like body on which an alignment film layer is subjected to a rubbing in advance, and then the coated surface is dried to form an optically anisotropic layer. As a manufacturing method of the optical film to form, the said coating liquid is apply | coated by the coating apparatus as described in any one of Claims 1-5, The manufacturing method of the optical film characterized by the above-mentioned.

According to Claim 8, the optical film of a favorable quality can be obtained, without making a stain generate | occur | produce on a coating surface.

(Effects of the Invention)

According to the present invention, stains such as vertical lines are not generated on the coated surface immediately after the coating, and homogeneous coating can be performed.

EMBODIMENT OF THE INVENTION Hereinafter, preferred embodiment of the bar coating apparatus and the coating method which concern on this invention is described according to an accompanying drawing.

First, the structure of the bar coating apparatus which concerns on this invention is demonstrated.

BRIEF DESCRIPTION OF THE DRAWINGS It is side cross-sectional view of the application | coating apparatus which shows one Embodiment of this invention. 2 is a perspective view showing a portion of the bar application head in cross section.

As shown in FIG. 1 and FIG. 2, the bar applicator 10 is provided with a bar applicator head 12 and a bar applicator head 12 interposed between the upstream side and the downstream side of the web traveling direction. Guide rollers 14 and 16 are provided. Then, the coating liquid is applied while the web 18 is wrapped in the bar 20 of the bar application head 12.

The bar application head 12 mainly supports a bar (wire bar) 20 rotatably supported by a bearing (not shown) at both ends, and supports the bar 20 over the entire length of the bar 20. And the upstream side beam member 28 which forms the liquid supply path | route 24 and 26 of the coating liquid between the bar accommodating member 22, and the bar accommodating member 22, and is provided with the liquid supply mechanism which supplies a coating liquid to The side beam member 30 is comprised.

The liquid supply passages 24 and 26 are composed of a manifold 32 and a slit 34, and the coating liquid supplied to the manifold 32 is uniformly extruded in the width direction of the web 18 through the slit 34. do. As a result, a primary bead 36 is formed on an upstream side (hereinafter referred to as a primary side) in the conveying direction of the web 18 with respect to the bar 20, and on the downstream side (hereinafter referred to as a secondary side) 2 The vehicle side beads 38 are formed. The secondary bead 38 acts to prevent air from mixing between the bar 20 and the bar receiving member 22.

The coating liquids forming the beads 36 and 38 on the primary side and the secondary side are picked up by the rotating bar 20 and wrapped on the bar 20 and applied to the web 18 continuously running. The excess coating liquid in the coating liquids supplied from the liquid supply paths 24 and 26 to the beads 36 and 38 on the primary side and the secondary side flows down the outer sides 28A and 30A of the upstream side beam members 28 and 30.

The rotation of the bar 20 may be any of the cases in which the rotation of the bar 20 is driven by the running of the web 18, and the driving of the bar 18 is performed in the same direction as the traveling direction of the web 18. Rotation in the reverse direction or rotation in the reverse direction may be sufficient.

FIG. 3: is explanatory drawing explaining the outline of the bar 20, and FIG. 4 is an expanded sectional view which shows the cross-sectional state of the wire of the bar surface seen from the axial cross section of the bar 20 of FIG.

As shown in FIG. 3, the bar 20 (wire bar) is produced by winding the wire 42 on the surface of the cylindrical core bar 40 to form a wire row 44. As shown in FIG. 4, the bar 20 can change the amount of the coating liquid held between the wires 42 of the wire rows 44 by changing the thickness of the wires 42, thereby providing a desired thickness. The coating film can be applied with high accuracy.

The wire 42 used for the bar 20 preferably has a wire diameter of 0.06 to 0.2 mm, more preferably 0.06 to 0.1 mm. If the wire diameter of the wire 42 exceeds 0.2 mm, the coating amount is too large and is not suitable as a usage method of the bar coating method effective for high speed thin film coating. Although the diameter of the bar 20 is not specifically limited, The thing of narrow diameter of the range of 3 mm-15 mm is preferable at the point which is suitable for thin layer application. Thus, the coating film of the thin film whose wet thickness is 5-15 micrometers can be obtained by apply | coating a coating liquid to the web 18 with the bar 20 of 3 mm-15 mm of bar diameters, and 0.06-0.2 mm of wire diameters.

In the bar application device 10 of FIG. 1, in the liquid storage portion at the outlet of the slit 34 formed on the secondary side of the bar 20, the excess coating liquid remaining on the surface of the bar 20 when applying is applied, and the slit 34. The coating liquid supplied from it joins. For this reason, variances, such as a vortex, generate easily in a coating liquid in a liquid storage part. Further, concentration distribution occurs in the volatile gas volatilized from the coating liquid on the slide surface 30A while the coating liquid in the liquid storage portion overflows the slide surface 30A of the downstream beam member 30, and the liquid storage portion The disturbances generated at amplify. Disruption of these liquid phases also causes disturbance of the gas phase, and causes vertical line unevenness to occur on the coated surface of the web 18 traveling near the slide surface 30A of the downstream beam member 30. In addition, the separation distance between the application surface of the web 18 and the apex of the slide surface 30A is very small, 2 mm or less, and when the concentration distribution of the volatile gas volatilized from the coating liquid is generated, it is easy to affect the application surface such as coating stains. .

Therefore, in this embodiment, the inclination angle of the slide surface 30A of the downstream side beam member 30 is made into the predetermined range, and the disorder of the coating liquid in the process of overflowing is alleviated.

5 is an enlarged cross-sectional view of the secondary side of the bar application head 12 according to the present invention.

As shown in FIG. 5, 30 A of slide surfaces of the downstream side beam member 30 are formed so that the inclination-angle (alpha) may be 5-30 degree with respect to horizontal. That is, when the inclination angle α of the slide surface 30A is less than 5 degrees, the inclination is too low, and the discharge of the coating liquid is stagnated. If the coating liquid is not discharged and is gradually accumulated on the slide surface 30A, the potential energy of the coating liquid is also increased, causing the web 18 to wave. On the other hand, when the inclination angle α of the slide surface 30A exceeds 30 degrees, the inclination becomes high, so that the coating liquid is dropletized and flows in order to have curvature by surface tension. By the action of dropletizing, the air flow around the coating liquid is further disturbed.

In addition, it is preferable to set the inclination angle so that the thickness t of the coating liquid falling on the slide surface 30A becomes 400 µm or less. That is, the viscosity of the coating liquid is η (cP), the flow rate of the coating liquid flowing on the slide surface 30A is q (residue) (m 3 / min), the density is ρ (kg / m 3), and the gravity acceleration is g (kgf). / Second), and when the inclination angle of the slide surface 30A is α (°), it is preferable that the inclination angle α is set to satisfy the following expression (1).

sin α ≧ 3 · η · q / {ρ · g · (4 × 10 ⁻⁴ ) ³ }. (Equation 1)

In addition to the inclination angle α, the physical properties (viscosity, density, etc.) of the coating liquid and the flow rate of the coating liquid may be adjusted.

The flow rate q (residue) is a flow rate per width of the coating liquid supplied from the liquid feed passage 26 to the beads 38 on the secondary side as q (supply), and is consumed for application in the coating liquid supplied from the feed liquid passage 26. When the flow rate is q (coat), the following equation (2) is established. Here, the flow rate of the coating liquid supplied to the bead 38 on the secondary side from the gap between the web 18 and the bar 20, and the beads 36 on the primary side from the gap between the bar 20 and the bar support surface 22A. It is assumed that the flow rates of the coating liquid returning to) are almost the same.

q (residue) = q (supply) -q (coat)... (Equation 2)

The downstream beam member 30 is arranged such that the vertex P (highest position) of the slide surface 30A is lower than the vertex Q (highest position) of the bar support member 22. In addition, the cross-sectional shape corresponding to the bar radial direction of the bar support surface 22A is formed in the concave shape which has at least the arc part which accommodates the bar 20. As shown in FIG. In FIG. 5, the vertex Q of the bar support surface 22A corresponds to the secondary side end portion of the bar support surface 22A. Thereby, in the liquid storage part 50 of the outlet of the slit 34 on the secondary side, after the coating liquid supplied from the slit 34 and the surplus coating liquid which flows on the surface of the bar 20 are joined, the coating liquid is a slide surface. It becomes easy to overflow to 30A smoothly. For this reason, it is easy to lose | disappear from the liquid storage part 50, and it can suppress that aberration is amplified.

The horizontal separation distance L1 of the vertex P of the slide surface 30A and the vertex Q of the bar receiving member 22 is preferably 1 mm or more. If the separation distance L1 is less than 1 mm, the liquid reservoir 50 at the outlet of the slit 34 on the secondary side is narrowed, and the coating liquid supplied from the slit 34 and the excess coating liquid flowing on the surface of the bar 20 are violently heated. It joins easily, and it becomes easy to generate | occur | produce variance, such as a vortex.

In addition, it is preferable that the distance L0 between the application surface of the web 18 and the apex of the slide surface 30A shall be 2 mm or less. Thereby, liquid sealing can be performed over the bar 20, the bar accommodating member 22, and the downstream side beam member 30. As shown in FIG. As a result, drying of the bar surface can be prevented, and mixing of bubbles can be prevented between the bar and the bar receiving member.

In addition, although the example in which the whole slide surface 30A of the downstream side beam member 30 was made into the said inclination angle was shown in FIG. 5, it is not limited to this, As shown in FIG. 6, the downstream side beam member 30 was shown. You may form so that a part of 30 A of slide surfaces near to the bar 20 may become the said inclination-angle. In this case, the area | region (slide surface length L2) of about 10-80 mm from the side close to the slit 34 among 30 A of slide surfaces of the downstream side beam member 30, More preferably, 15-40 mm. It is preferable to satisfy this inclination angle. Moreover, it is good also as a structure provided with the inclination-angle adjustment mechanism which can adjust the inclination-angle of 30 A of slide surfaces in the downstream beam member 30. As shown in FIG.

Next, the coating method which apply | coats a coating liquid to the web 18 by the bar coating apparatus 10 comprised as mentioned above is demonstrated with reference to FIG. 1 and FIG.

The coating liquid is supplied into the feed passages 24 and 26 of the coating head 12 to form beads 36 and 38 on the primary side and the secondary side, and is picked up by the rotating bar 20 to be transferred to the web 18. Is applied. At this time, the coating liquid is measured at the contact portion between the web 18 and the bar 20 so that only a desired coating amount is applied to the web 18, and the other coating liquid is applied to the upstream beam member 28 and the downstream beam. It flows along the outer surface of the member 30.

In this bar application, in this embodiment, the inclination angle of the slide surface 30A of the downstream beam member 30 of the bar application device 10 is in the range of 5 to 30 degrees, so that spots such as vertical lines are not generated on the application surface. You can do that.

That is, the coating liquid can be smoothly discharged on the slide surface 30A without dropping and flowing by the surface tension. As a result, the coating liquid flows through the slide surface 30A in a uniform thin film form in the web width direction, and the concentration distribution of the volatile gas volatilized from the coating liquid also hardly occurs. Therefore, the density | concentration distribution of volatile gas does not generate | occur | produce in the gas phase between the slide surface 30A and the coating surface of the web 18, and it can suppress that a vertical line | surface stain generate | occur | produces on a coating surface.

Moreover, as shown in said Formula 1, the inclination angle (alpha) of the slide surface 30A is set so that the liquid film thickness of the coating liquid which may fall on 30 A of slide surfaces may be 400 micrometers or less. Thereby, a coating liquid can flow in a more uniform thin film form on the slide surface 30A, and a more uniform volatile gas atmosphere can be formed in the vicinity of the coating surface immediately after application | coating.

Thus, according to this embodiment, the stain | polishing of a vertical line etc. does not generate | occur | produce on a coating surface immediately after application | coating, and can apply uniformly.

Next, the application example of the bar coating apparatus 10 which concerns on this invention is demonstrated. Fig. 7 is a production line 80 of the optical compensatory sheet on which the bar coating device 10 of the present invention is mounted.

In the manufacturing line 80 of the optical function film, as shown in FIG. 7, the web 18 which is a transparent support body in which the polymer layer for oriented film formation was formed previously is sent out from the delivery machine 82. FIG. Subsequently, the web 18 is guided by the guide roller 84 and supplied to the rubbing processing apparatus 86. And the rubbing process is given to the polymer layer of the web 18 by the rubbing roller 88. FIG. A vibration damper 90 is installed downstream of the rubbing roller 88 to remove dust adhering to the surface of the web 18. Downstream of the vibration damper 90, the bar application head 12 according to the present invention is provided. Then, the coating liquid containing the discomatic liquid crystal is applied to the web 18 by the bar application head 12. Downstream of the coating head 12, the drying zone 92 and the heating zone 94 are formed one by one, and the coating liquid on the web 18 is dried and heated, and a liquid crystal layer is formed. An ultraviolet lamp 96 is further provided downstream, and the liquid crystal is crosslinked by ultraviolet irradiation to form a desired polymer. An optical compensation film is manufactured by this, and the produced optical compensation film is wound up by the winding machine 98. FIG.

Thus, since the bar coating apparatus 10 which concerns on this invention is used for application | coating of the liquid crystal layer of an optical compensation film (application | coating of the coating liquid containing a diconnematic liquid crystal), the favorable film | membrane which does not have a stain, such as a vertical line, is manufactured. can do.

The webs 18 used in the present invention include paper, plastic film, resin coated paper, synthetic paper and the like. The material of the plastic film is, for example, polyolefin such as polyethylene or polypropylene, vinyl polymer such as polyvinyl acetate, polyvinyl chloride, polystyrene, polyamide such as 6,6-nylon or 6-nylon, polyethylene terephthalate, polyethylene Polyesters such as -2,6-naphthalate, cellulose acetates such as polycarbonate, cellulose triacetate, cellulose diacetate and the like. Moreover, although polyolefin including polyethylene is typical as resin used for resin coated paper, it is not necessarily limited to this. Although the thickness of a web is not specifically limited, either, about 0.01 mm-about 1.0 mm is handled, and it is advantageous from the versatility.

The coating liquid used for this invention does not have limitation in particular, The water or organic solvent liquid of a high molecular compound, a pigment dispersion liquid, a colloidal solution, etc. can be applied. In particular, a coating liquid of various optical films, for example, a liquid crystalline discotic coating liquid or the like, which is required to perform thin layer coating uniformly and with high accuracy is preferable. In addition, when the viscosity of a coating liquid is high, it depends also on a coating film thickness, an application | coating speed, the drying rate after application | coating, etc., but since 0.5 or less of the eye of a wire eye or a groove does not disappear and a bar line malfunctions, 0.5 Pa * s or less is preferable.

As mentioned above, although preferred embodiment of the bar coating apparatus and the coating method which concern on this invention was described, this invention is not limited to the said embodiment, A various form can be employ | adopted.

For example, in the said embodiment, although it demonstrated in the example which uses the wire bar as the bar 20, it is not limited to this, For example, a groove cutting bar, a flat bar, etc. may be sufficient.

EXAMPLE

Hereinafter, although an Example is given and the characteristics of this invention are demonstrated further more concretely, the scope of the present invention is not limited to the specific example shown below.

Example 1

In the manufacturing line 80 of the optical compensation film of FIG. 7 equipped with the bar coating apparatus 10 which concerns on this invention, the influence on the vertical line failure immediately after application | coating was evaluated.

The web 18 was applied to a surface of a triacetyl cellulose (Fuji Tak, Fujishashin Film Co., Ltd.) having a thickness of 100 μm so that a 2 wt% solution of long-chain alkyl-modified foam was 25 ml per 1 m 2 of film, and then 60 ° C. Dried for 1 minute to form a resin layer for alignment film was used. While sending out this web 18 from the sending machine 82, and carrying out at 50 m / min, the rubbing process was performed to the resin layer surface for oriented films with the rubbing processing apparatus 86, and the oriented film was formed. The pressing force of the rubbing roller 88 in the rubbing treatment was 10 kgf / cm 2 per 1 cm 2 of the alignment film resin layer, and the rotational circumferential speed was 5.0 m / sec.

And the coating liquid was apply | coated using the bar application apparatus 10 on the orientation film obtained by rubbing the resin layer for orientation films. The coating solution is an ethylene oxide-modified trimetholpropane triacrylate {V # 360, Osaka Yukika) with respect to a mixture of 4: 1 in a weight ratio of R (1) and R (2) of the discotic compound TE-8 shown below. 10 wt% of Gaku Co., Ltd.}, 0.6 wt% of cellulose acetate butyrate (CAB531-1, manufactured by Eastman Chemical Co., Ltd.), 3 wt% of photopolymerization initiator {Irgacure 907, Nippon Chiba Co., Ltd.} 1 weight% of a sensitizer (Kayacure DET-X, Nippon Kayaku Co., Ltd.) was added, and it was finally made into the 32 weight% methyl ethyl ketone solution of this mixture. 0.3 weight% of surfactant (fluoro aliphatic group containing copolymer, Megapack F780, Dainippon Ink Co., Ltd. product) was further added, and was used as coating liquid.

In the bar application device 10 of FIG. 5, the bar 20 of the wire 42 having a bar diameter of 8 mm and a wire diameter of 80 μm is supported on the bar supporting surface 22A, and the web 18 is driven at a traveling speed. The bar 20 was also rotated forward at the same speed while traveling at 24 to 36 m / min, and the coating liquid was applied from the bar application head 12 onto the alignment film so as to be 5 ml per 1 m 2 of the web (5 μm wet film thickness). In addition, the inclination angle (alpha) of the slide surface 30A of the downstream side beam member 30 was 22 degree | times, and the slide surface length L2 was 15 mm.

The coating liquid has a viscosity η of 3 × 10 ⁻³ cP at a normal temperature (25 ° C.), a density ρ of 0.85 to 0.95 kg / L, a flow rate per width q (supply) of 4.074 × 10 ⁻⁵ (m 3 / min), q The coat had a 3.0 × 10 ⁻⁵ (m 3 / min) and q (reside) of 1.074 × 10 ⁻⁵ (m 3 / min).

And immediately after application | coating, the unevenness | corrugation of the vertical line of the application surface of the secondary side web 18 of the bar 20 was evaluated by visual confirmation. Evaluation criteria were as follows.

○… Level that satisfies manufacturing quality with little stain on vertical line

? Slightly visible spots on the vertical line but no manufacturing problem

×… Levels that are rejected without satisfying product quality due to many vertical lines

The evaluation results are shown in Table 1.

(Example 2)

In the downstream beam member 30, it was similar to Example 1 except having set the inclination angle (alpha) of 30 A of slide surfaces to 30 degree, and making slide surface length L2 40 mm. The results are shown in Table 1.

(Example 3)

In the downstream beam member 30, it was similar to Example 1 except having set the inclination angle (alpha) of the slide surface 30A to 5 degrees, and making the slide surface length L2 into 10 mm. The results are shown in Table 1.

(Example 4)

In the downstream beam member 30, it was similar to Example 1 except having set the inclination-angle (alpha) of the slide surface 30A to 30 degree, and making the slide surface length L2 into 80 mm. The results are shown in Table 1.

(Comparative Example 1)

In the downstream beam member 30, it was similar to Example 1 except having set the inclination-angle (alpha) of the slide surface 30A to 45 degree | times, and setting the slide surface length L2 to 5 mm. The results are shown in Table 1.

As shown in Table 1, in Examples 1-4 in which the inclination-angle (alpha) of the slide surface 30A in the downstream side beam member 30 satisfies the range of 5-30 degree, all the irregularities on a vertical line were almost There was no. On the other hand, in the comparative example 1 in which the inclination angle (alpha) exceeds 30 degree | times, the irregularity of the vertical line generate | occur | produced a lot.

Moreover, it turned out that even if the slide surface whole is not made into the said inclination angle, even if the slide surface length L2 is 10-80 mm, the irregularity on a vertical line can be suppressed.

As mentioned above, it was confirmed that the generation | occurrence | production of the vertical line | wire stain can be suppressed in the coating surface immediately after application | coating by applying this invention.

1 is a side sectional view of a bar application device of the present embodiment.

2 is a perspective view showing a part of the bar application device of the present embodiment in cross section.

It is explanatory drawing explaining the bar of this embodiment.

4 is a cross-sectional view of the bar in the present embodiment.

5 is an enlarged cross-sectional view of the vicinity of a downstream beam member of the bar application device of FIG. 1.

6 is an enlarged cross-sectional view showing a modification of the downstream beam member in the present embodiment.

7 is an explanatory diagram of a production line of an optical compensatory sheet on which the bar coating device of the present embodiment is mounted.

8 is a side cross-sectional view illustrating a conventional bar application device.

(Explanation of symbols for the main parts of the drawing)

10: bar application device 12: bar application head

14, 16: guide roller 18: web

20: bar 22: bar receiving member

24, 26: liquid supply passage 28: upstream beam member

30: downstream beam member 30A: slide surface

32: manifold 34: slit

36: primary bead 38: secondary bead

40: core bar of the bar 42: wire

44: wire row 22A: bar support surface

50: liquid reservoir

Claims (8)

Applying a coating liquid to the band-like body running; A support member installed below the bar and rotatably supporting the bar; And It is provided adjacent to the upstream and downstream of a strip | belt-shaped body traveling direction through the said support member, and is provided with the upstream side beam member and downstream side beam member which form the slit which respectively supplies a coating liquid between the said support member, ; The inclination angle of the inclined surface facing the band-like body of the downstream beam member is 5 to 30 degrees. The coating liquid according to claim 1, wherein the coating liquid has a viscosity of η (cp), a density of ρ (kg / m 3), a gravitational acceleration of g (kgf / sec), and a coating liquid flowing on the slope of the downstream beam member. When the flow rate is q (m 3 / sec) and the inclination angle is α (°), the inclination angle α of the slope of the downstream beam member is set to satisfy the following formula (1). . sin α ≧ 3 · η · q / {ρ · g · (4 × 10 ⁻⁴ ) ³ }. (Equation 1) The bar application apparatus according to claim 1 or 2, wherein a range of 10 to 80 mm or more is defined as the inclination angle from a side close to the slit among the slopes of the downstream beam member. The bar coating apparatus according to any one of claims 1 to 3, wherein a distance in the horizontal direction between a vertex of the bar supporting member and a vertex of the downstream beam member is 1 mm or more. The bar coating device according to any one of claims 1 to 4, wherein a vertex of the downstream beam member is lower than a vertex of the bar support member. The coating liquid is apply | coated to the strip | belt-shaped body which travels using the bar coating apparatus as described in any one of Claims 1-5. 7. The coating method according to claim 6, wherein the separation distance between the apex of the downstream beam member and the surface of the band-like body is 2 mm or less. As a manufacturing method of the optical film which apply | coats the coating liquid containing a liquid crystalline discotic compound on the strip | belt-shaped object in which the orientation film layer by which the rubbing process was formed previously, is dried, and the said coating surface is dried and forms an optically anisotropic layer: The said coating liquid is apply | coated by the bar coating apparatus in any one of Claims 1-5, The manufacturing method of the optical film characterized by the above-mentioned.

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