JP2011167613A - Method of forming coated film and method of manufacturing coated film laminate - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of forming coated film for taking an allowance range of a gap between a die and a base material large in coated film formation by slot coating, and to provide a method of manufacturing coated film laminate. <P>SOLUTION: The method of forming coated film includes: a step of arranging a sheet-like base material on a roller having a diameter D (mm); a step of causing the roller to rotate; and a step of supplying coating liquid from the die to the surface of the base material rotating while following up the roller, wherein the die has an upstream side lip surface as a surface capable of retaining the coating liquid between the die and the base material and a downstream side lip surface which is arranged more on the downstream side in the rotation direction from the upstream side lip surface and is a surface capable of retaining the coating liquid between the die and the base material, an interval that ejects the coating liquid is formed between the upstream side lip surface and the downstream side lip surface and the length of the upstream side lip surface in the roller rotation direction is 2.0-0.02D (mm). <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a method for forming a coating film on a substrate surface by slot coating using a die and a method for manufacturing a coating film laminate.

  A coating layered product in which a coating film having a predetermined function is formed on a base material, such as an electrophotographic photosensitive member, a solar cell, and an optical functional filter such as a color filter, is used in many devices. It has been. Various methods for forming a coating film on a substrate have been proposed according to the characteristics of the coating film.

  One of such methods for forming a coating film is a method for forming a coating film by slot coating. This is a method in which a die for supplying a liquid coating liquid is opposed to a planar or roll-shaped substrate, and the coating liquid is supplied to the surface of the substrate while traveling relatively in one direction. That is, using a die in which a coating liquid discharge port is formed by a lip having an upstream lip located on the upstream side in the running direction of the substrate and a downstream lip located on the downstream side, between the lip and the substrate surface A coating film having a predetermined film thickness is formed on the surface of the substrate by discharging the coating liquid from the coating liquid discharge port while maintaining a certain interval.

  Patent document 1 and patent document 2 disclose such a coating method by slot coating. In these documents, application defects can be suppressed or application speed can be improved by satisfying the conditions described herein.

JP 2004-216298 A JP 2003-10773 A

  As described above, in the method of forming a coating film by slot coating, it is necessary to keep the distance between the die and the substrate within a predetermined range. If this interval is too small, the internal pressure of the coating solution existing in the interval increases, and dripping occurs. Conversely, if this distance is too large, air in the atmosphere will be entrained. In either case, an appropriate coating film cannot be formed, and in order to avoid this, control of the interval is important.

  However, in the conventional techniques described in Patent Document 1 and Patent Document 2, the range of allowable intervals for avoiding the above-described problems has been narrow. For this reason, there is a problem that it takes a lot of time and effort to control the distance, and it is difficult to keep the distance within an allowable range over the entire width when a coating film is formed (applied) on a wide substrate. It was.

  Accordingly, in view of the above problems, the present invention provides a method for forming a coating film and a method for manufacturing a coating film laminate that can provide a large allowable range of the gap between the die and the substrate in forming a coating film by slot coating. The task is to do.

  The present invention will be described below. Here, for ease of understanding, reference numerals of the drawings are given in parentheses, but the present invention is not limited to this.

  According to the first aspect of the present invention, a sheet-like base material (1) is arranged on a roll having a diameter D (mm), the roll is rotated, and the die (10) is rotated on the surface of the base material following the roll. The coating liquid (2) is supplied from the substrate to form a coating film, the die having an upstream lip surface (11a) which is a surface capable of holding the coating liquid between the substrate and the upstream lip A downstream lip surface (12a) that is disposed downstream of the surface in the direction of rotation and is capable of holding the coating liquid between the substrate and the upstream lip surface and the downstream lip surface; A gap (G) at which the coating liquid is discharged is formed between the two, and the length of the upstream lip surface in the roll rotation direction is 2.0 (mm) or more and 0.02 D (mm) or less. This is a film forming method.

  The invention according to claim 2 is the coating film forming method according to claim 1, wherein the length of the upstream lip surface (11a) in the roll rotation direction is longer than the length of the downstream lip surface (12a). Characterized by its long length.

  A third aspect of the present invention is the coating film forming method according to the first or second aspect, wherein the coating film width is 1000 (mm) or more.

  Invention of Claim 4 includes the process of apply | coating a coating film on a base material by the coating-film formation method as described in any one of Claims 1-3, and the process of drying the apply | coated coating film. It is a manufacturing method of a coating-film laminated body.

  According to the present invention, in forming a coating film by slot coating, a large allowable range of the gap between the die and the substrate can be obtained. As a result, the control of the interval can be facilitated, and furthermore, application to a wider base material can be appropriately performed.

It is sectional drawing which represented typically the shape of the die | dye used among the coating-film formation methods which concern on one embodiment. FIG. 2 is a diagram showing symbols for various dimensions and positional relationships in FIG. 1.

  The above-mentioned operation and gain of the present invention will be clarified from the following embodiments for carrying out the invention. Hereinafter, the present invention will be described based on embodiments shown in the drawings. However, the present invention is not limited to these embodiments.

  FIG. 1 is a cross-sectional view schematically showing the structure of a die 10 used in a coating film forming method according to one embodiment. FIG. 1 also shows a base material 1 on which a coating film is formed, and a coating liquid 2 to be a coating film. The die 10 extends substantially in the back / front direction of the drawing while maintaining the cross section shown in FIG. Further, FIG. 2 shows symbols such as dimensions related to the die 10 and its arrangement.

  The die 10 includes an upstream lip 11 and a downstream lip 12 disposed on the downstream side of the upstream lip 11 with respect to the direction in which the coating film is formed. A gap G is formed between the upstream lip 11 and the downstream lip 12.

As can be seen from FIGS. 1 and 2, the upstream lip 11 includes an upstream lip surface 11a, an inclined surface 11b, and a gap forming surface 11c.
The upstream lip surface 11 a is a surface having a length t ₁ disposed to face the base material 1. Upstream lip surface 11a is positioned with a gap of the substrate 1 and the distance d ₁ as shown in FIG. The upstream lip surface 11a is a surface that allows at least a part of the upstream lip surface 11a to be in contact with the coating liquid 2 when the die 10 and the substrate 1 are moved relative to each other to apply the coating liquid 2, and hold the coating liquid 2 here. It is.
The inclined surface 11b is a surface to be arranged so bent from the upstream end of the upstream lip surface 11a, has an angle of theta ₁ to the upstream side lip surface 11a.
The gap forming surface 11c is a surface formed substantially perpendicularly from the downstream end of the upstream lip surface 11a, and forms a gap G with a gap forming surface 12d of the downstream lip 12 described later.

The length t ₁ of the upstream lip surface 11a is 2.0 (mm) or more and 0.02 D (mm) or less. Here, D is the diameter (mm) of the roll on which the substrate 1 is disposed. When t ₁ is smaller than 2.0 (mm), the dripping due to the increase in the hydraulic pressure due to the distance (d ₁ ) between the upstream lip surface 11a and the base material 1 is likely to occur, and the tolerance of d ₁ The range becomes narrower. On the other hand, if t ₁ is larger than 0.02 D (mm), the lip surface gradually moves away from the roll surface due to the curvature of the roll. For example, when adjusting the distance between the roll and the lip surface, a wasteful part may become an obstacle and the lip itself may increase in weight.

Gap d ₁ is the size of the gap between the upstream lip surface 11a and the substrate 1, which is required to be within an appropriate range. If the appropriate range of d ₁ is large, the control of the gap becomes easy. In addition, since the appropriate range of d ₁ is large, it is easy to adjust the position of the die even on a substrate that is wide in the width direction (backward / frontward direction in FIG. 1), and the problem of deviating from appropriate application conditions locally. Can be reduced. For example, even when the coating film width is 1000 mm or more, the coating can be performed without any trouble. Specifically appropriate range of d ₁ to be used depend upon t ₁ but, by t ₁ is in the range described above, it is possible to increase this range as compared with the prior art.
Incidentally, it may involve air increases in the coating solution gap d ₁ is larger than the appropriate range. On the other hand, the internal pressure of the coating liquid gap d ₁ is smaller than the appropriate range is increased, dripping occurs.

θ ₁ has an angle that can prevent the advancement of the inclined surface 11b of the upstream lip even when the portion where the coating liquid 2 is in contact with the upstream lip surface 11a moves forward so that the inclined surface 11b does not contact the coating liquid 2. If you do.

As shown in FIGS. 1 and 2, the downstream lip 12 includes a downstream lip surface 12a, a first inclined surface 12b, a second inclined surface 12c, and a gap forming surface 12d.
The downstream lip surface 12 a is a surface having a length t ₂ that is disposed to face the base material 1. Downstream lip surface 12a is positioned with a gap of the substrate 1 and the distance d ₂ as shown in FIG. The downstream lip surface 12a is a surface that comes into contact with and can hold the coating liquid 2 when the die 10 and the substrate 1 move relatively to apply the coating liquid 2.
First inclined surface 12b is a surface to be arranged so bent from the downstream end of the downstream lip surface 12a, has an angle of theta ₂ with respect to the downstream lip surface 12a.
The 2nd inclined surface 12c is a surface arrange | positioned so that it may bend from the edge part of the 1st inclined surface 12b, and has the angle of (theta) ₃ with respect to the 1st inclined surface 12b.
The gap forming surface 12d is a surface formed substantially perpendicularly from the upstream end of the downstream lip surface 12a, and forms a gap G with the gap forming surface 11c of the upstream lip 11 described above.

The length t ₂ of the downstream side lip surface 12a, from the viewpoint of maintaining a stable amount of the coating solution 2 to be held between the downstream side lip surface 12a and the substrate 1, is preferably short. However, if it is too short, processing may be difficult or thermal deformation may occur easily, and therefore, it is preferably about 1.0 mm to 1.5 mm. The length t ₂ of the downstream side lip surface 12a is preferably shorter than the top side lip surface t _1. As a result, the possibility of dripping can be reduced.

Gap d _2, this tends to leave more than necessary the coating liquid at the edge of too large downstream lip surface 12a, is likely to coated surface is disturbed. On the other hand, the liquid pressure of the coating liquid between the gap d ₂ is too small and the downstream lip surface 12a and the substrate 1 becomes high, dripping is likely to occur on the upstream side lip surface 11a side is increasing coating solution.

θ ₂ is inclined such that the interface of the coating liquid 2 is formed at the boundary between the downstream lip surface 12a and the first inclined surface 12b. Thereby, the coating liquid 2 is stabilized, the smoothness of the coating film to be formed can be improved, and the dirt of the die 10 can be prevented.
The specific range of the angle θ ₂ is not limited because it is optimized depending on the viscosity of the coating liquid 2 and the coating conditions, but an obtuse angle (the downstream of the angles formed by the downstream lip surface 12a and the first inclined surface 12b). It is preferable that the inner side of the side lip 12 has an acute angle) or 90 °. Among these, 90 ° is more preferable from the viewpoint of ease of processing.

If θ ₃ is too large, the rigidity of the downstream lip 12 decreases. Conversely, if θ ₃ is too small, the weight increases. Therefore, an appropriate angle is set in consideration of this.

  A gap G formed between the gap forming surfaces 11c and 12d communicates with a coating liquid flow path (not shown) and a manifold as an intermediate coating liquid storage section to form a coating liquid discharge port. The size of the gap G can be appropriately changed according to the viscosity of the coating liquid 2, the coating conditions, the film thickness of the target coating liquid, and the like, and is not limited. For example, in the case of applying a coating solution having a low viscosity at a high speed, the size of the gap G is preferably 10 μm to 200 μm at the position where the coating solution is discharged. If the gap G is too narrow, it may be difficult to form a constant gap due to a problem of mechanical accuracy, and may be clogged with foreign matter. If the gap G is too wide, the volume of the coating liquid reservoir of the manifold increases. Therefore, the liquid tends to stay.

  The material of the die 10 is not particularly limited, and for example, metal, ceramics, glass, mineral, thermosetting resin, thermoplastic resin, a composite thereof, or the like is used. The die 10 may have a structure that can be divided into a lip portion and another portion. In this case, the material of the lip portion may be different from the other portions. Furthermore, the surface of the die, particularly the lip surface, the inclined surface, and the gap forming surface are chemically treated such as a hydrophilic treatment and a hydrophobic treatment, a smooth treatment, and a polishing treatment in order to make the relationship with the coating solution more preferable. Further, physical processing such as surface roughening may be performed.

  The material of the substrate 1 on which the coating film is formed is not particularly limited, and examples thereof include glass, metal, semiconductor, ceramics, thermosetting resin, thermoplastic resin, mineral, and composites thereof. . The surface of the substrate may be smooth or uneven. As for the degree of unevenness, a good coating film is obtained in which the level difference is approximately 10 times the dry (or solidified) coating film thickness. Examples of the irregularities include irregularities due to a lattice, partition walls, bumps, spacers, pixel patterns, circuit patterns, and the like. Furthermore, although the base material 1 forms the coating layer immediately after application | coating as needed, the base material 1 may be the material and structure which impregnates, osmose | permeates or absorbs a coating liquid after progress for a predetermined time.

  The coating solution 2 as a material for the coating film is not particularly limited in composition as long as it has a required function and can cover the surface of the substrate 1. Solvents such as water and water, binders such as polymers, colorants such as pigments and dyes, photosensitive agents, fillers such as ceramic powder, conductivity imparting agents, thickeners, surfactants, surface modifiers, foaming agents, Examples thereof include additives such as curing agents, reinforcing agents, and softening agents.

The properties of the coating liquid 2 are not particularly limited, and various properties such as a suspension, a slurry, and a paste can be used in addition to a uniform solution, and further, bubbles may be included. Moreover, the coating liquid 2 may have viscoelasticity.
The viscosity of the coating solution 2 can be appropriately changed depending on the composition and coating conditions of the coating solution 2, the target coating film thickness, and the like. Usually, the viscosity under the coating conditions is 1 cp to 1000 cp, preferably 2 cp to 500 cp, More preferably, it is 3 cp-100 cp. When the viscosity is large, the upper limit of possible coating speed is small. On the other hand, if the viscosity is too small, dripping or the like tends to occur.

Next, the manufacturing method of the coating-film laminated body containing the coating-film formation method concerning one embodiment is demonstrated.
As can be seen from FIGS. 1 and 2, in the manufacturing method, the coating liquid 2 is supplied from the gap G (coating liquid discharge port) of the die 10 to the surface of the substrate 1 arranged on a rotating roll, and the coating is performed. A liquid is laminated | stacked on the base material 1 by predetermined thickness. Details are as follows.

After the interval between the die 10 and the substrate 1 is set according to the characteristics of the coating liquid 2 and the film thickness of the target coating film, the coating liquid 2 is pushed out from the coating liquid discharge port of the die 10.
The coating liquid 2 is pushed out from the coating liquid discharge port and is held between the base material 1 and the lip surfaces 11a and 12a.

Here, the distance between the substrate 1 and the die 10 is appropriately changed depending on the viscosity of the coating liquid 2, the coating conditions, the target coating thickness, and the like, and is not limited. In the present invention, the upstream side lip surface 11a of the die 10 has the length (t ₁ ) as described above. Thereby, even if the internal pressure of the coating liquid 2 hold | maintained between the upstream lip surface 11a and the base material 1 is large, it is possible to hold | maintain this coating liquid 2 appropriately. Therefore, even when the die 10 and the base material 1 are arranged close to each other, dripping is less likely to occur. This also means that it is possible to widen the permissible range of the interval at which the coating film can be formed properly, and even when the variation in the spacing in the width direction is large when the coating film is formed on a wide substrate. An appropriate coating film can be formed. For example, even when the coating film width is 1000 mm or more, it is possible to apply appropriately. Conventionally, it has been difficult to appropriately form a coating film on a substrate having a narrow tolerance and a wide width.

  Moreover, since the base material 1 is arrange | positioned on a roll, it has the curvature substantially the same as a roll. Therefore, the base material 1 has a point (a line when considering the depth direction) that is closest to the upstream lip surface 11a and the downstream lip surface 12a. In consideration of the curvature of the roll and the inclination at the time of installation in actual equipment, the closest point (line) is preferably at any position on the upstream lip surface 11a.

  After the coating liquid 2 comes into contact with the base material 1 and an interface is formed between the upstream lip 11 and the base material 1, and between the downstream lip 12 and the base material 1, coating is started by rotating the roll. The The relative movement between the base material 1 and the die 10 may be such that either the die 10 or the base material 1 is fixed or the both move relatively. The distance between the substrate 1 and the die 10 can be changed during the movement. By changing in this way, it is possible to make the coating liquid 2 held between the die 10 and the substrate 1 more stable and improve the smoothness of the coating film. Also in this case, in the present invention, since the allowable range is widened as described above, the adjustment opportunity can be reduced or the adjustment can be facilitated.

  Contrary to this method, after the relative movement between the substrate 1 and the die 10 is started in advance, the supply of the coating liquid 2 can be started from the coating liquid supply port.

  The application operation is usually terminated by stopping the supply of the application liquid 2 when the application liquid 2 is applied to the target site on the surface of the substrate 1. In that case, although the space | interval of the base material 1 and the die | dye 10 may be expanded, this operation may be performed after stopping a relative movement or may be performed during a relative movement. By extending the distance between the base material 1 and the die 10 at the end of coating, the liquid breakage tends to be good, and the smoothness of the coating film edge is improved, and the stain resistance of the die is improved. May improve.

  A preferred ratio of the film thickness of the coating film to the distance between the substrate 1 and the die 10 is usually 0.01 to 0.5. If the film thickness ratio exceeds this range, the smoothness of the coating film may deteriorate, and if it is less than this range, the upper limit of the coating speed at which a stable coating state can be obtained becomes smaller and the productivity tends to decrease. It is in. Preferably it is 0.05-0.4.

  Although the relative moving speed of the base material 1 and the die 10 during coating is not limited, it is usually 0.005 m / sec to 1 m / sec. If the coating speed exceeds this range, the liquid is liable to dry out. On the other hand, if the coating speed is less than this range, the productivity tends to decrease, which is not desirable. Preferably, it is 0.01 m / second to 0.5 m / second.

  The temperature of the coating liquid 2 at the time of application | coating is not limited, What is necessary is just a fluid state to the extent that application | coating of the coating liquid 2 is possible.

  The coating solution 2 after coating is usually dried using a hot plate, an IR oven, a convection oven, a vacuum dryer, a heating vacuum dryer or the like. The drying temperature is not limited because it is optimized by the composition and viscosity of the coating solution, the film thickness of the coating film, etc., but is usually in the range of 20 ° C to 200 ° C, preferably 25 ° C to 150 ° C. Also, the drying time is not limited, but is usually in the range of 1 second to 100 seconds, preferably 5 seconds to 60 seconds. When the coating solution is a self-reactive or self-curing compound or does not contain a solvent, a solidified coating film can be formed by natural standing drying or natural cooling. The film thickness after drying is usually in the range of 0.1 μm to 100 μm, preferably 0.5 μm to 50 μm.

In the examples, the conditions of the die and the base material were changed, and the allowable range of the distance (d _{1 in} FIG. 2) between the upstream lip surface and the base material capable of appropriately forming a coating film was examined. This will be described below.

  Table 1 shows the die shape, roll diameter, and roll peripheral speed. The symbols used in Table 1 have the same meaning as in FIG.

  Other conditions are as follows. As the substrate, a PET (polyethylene terephthalate) sheet having a thickness of 100 μm was used. The coating solution was a PCr solution (CPH-PCr) containing 20% by mass of Sc and a solvent having a TL of 30% by mass and THF of 70% by mass. The viscosity of the coating solution was 140 cP.

  The discharge direction of the coating liquid was set such that the extending direction of the slot (interval G) was the center of the roll. Drying after coating was carried out by leaving it to stand in an atmosphere at room temperature for 40 seconds and then at 100 ° C. for 30 seconds and further at 140 ° C. for 60 seconds. The thickness of the coating after drying was set to 20 μm (average).

Under the above conditions, the distance between the die and the base material was changed, the state of the coating film was observed, and the upper and lower limits of the distance were examined. Table 2 shows the results. Table 2 shows the maximum d ₁ does not cause a _problem, and a minimum of d ₁ that does not cause a problem with reason, revealed the appropriate movable range of the die by the difference between the maximum d ₁ and a minimum d _1.

As can be seen from Table 2, no. 1-No. 4, good results can be obtained especially at the minimum d ₁ . That is, as indicated by “maximum d ₁ -minimum d ₁ ”, an appropriate movable range of the die can be widened.

  Although the present invention has been described with reference to embodiments that are presently practical and preferred, the present invention is not limited to the embodiments disclosed herein, The invention can be changed as appropriate without departing from the scope or spirit of the invention that can be read from the claims and the entire specification, and a coating film forming method involving such a change, and a coating film laminate manufacturing method are also disclosed in the present invention. Should be understood as being included in the scope.

DESCRIPTION OF SYMBOLS 1 Base material 2 Coating liquid 10 Die 11 Upstream lip 12 Downstream lip

Claims (4)

A sheet-like base material is placed on a roll having a diameter D (mm), the roll is rotated, and a coating liquid is formed by supplying a coating solution from a die onto the surface of the base material that rotates following the roll. A method,
The die has an upstream lip surface that is a surface capable of holding the coating liquid between the base and the die;
A downstream lip surface that is disposed on the downstream side in the rotation direction from the upstream lip surface and is a surface capable of holding the coating liquid between the base material and the lip surface;
An interval is formed between the upstream lip surface and the downstream lip surface to discharge the coating liquid,
The coating film formation method whose length of the said roll rotation direction of the said upstream lip surface is 2.0 (mm) or more and 0.02D (mm) or less.   The coating film forming method according to claim 1, wherein a length of the upstream lip surface in the roll rotation direction is longer than the length of the downstream lip surface.   The coating film forming method according to claim 1 or 2, wherein the coating film width is 1000 (mm) or more.   The manufacturing method of the coating-film laminated body including the process of apply | coating a coating film on the said base material by the coating-film formation method as described in any one of Claims 1-3, and the process of drying the said apply | coated coating film. .

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