JP2007313417A - Die head and coating method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a die head with a simple structure capable of performing fine stripe-like coating, and a method for performing stripe-like coating using the die head. <P>SOLUTION: A large number of grooves are formed on a land part of a distal end of the die head 11 with a desired pitch and when a coating liquid is delivered from the die head 11 in a film-like form and a base material 24 is coated with it, a coating gap between the die head 11 and the base material 24 is increased, thereby the coating liquid delivered in the film-like shape is broken taking advantage of the groove. By performing coating in the state, a stripe-like coating film 26 having a break 27 is formed on the base material 24. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a die head used for performing striped coating on a flat substrate or a web-shaped substrate, and a coating method using the die head.

  Conventionally, a die head having a pair of die head halves having a structure for forming a slit for discharging a coating solution by being opposed to each other is known, and the die head is used to apply to a substrate to be coated. On the other hand, it is known to apply at a constant width. In addition, it is also known that a discharge portion and a non-discharge portion are provided in the die head tip discharge port, and stripe-like coating is performed using the die head. 5 and 6 show a conventional die head 1 used for stripe coating. The die head 1 is assembled with a pair of die head halves 2 and 3 having a structure for forming a slit 7 for discharging the coating liquid by assembling with a bolt (not shown) or the like facing each other, and side plates attached to both ends thereof. 4 and 4 and a shim 5 sandwiched between the pair of die head halves 2 and 3. One die head half 2 is also called a manifold plate and includes a manifold 6 for supplying a coating solution to the slit. The other die head half 3 is also called a flat plate, and the surface facing the mating die head half 2 is a flat surface. The shim 5 includes a base portion 5a disposed in the entire lower region of the manifold 6 in FIG. 6 and a branch portion 5b for dividing the slit 7 into a plurality of regions.

  In the die head 1 having this configuration, the coating liquid is not discharged in the region where the branch portion 5b exists in the slit 7, but the application liquid is discharged from the region between the branch portions 5b, thereby performing stripe-shaped coating. be able to. In the die head 1 using the shim 5, by manufacturing the shim 5 having a shape capable of being applied with a desired stripe width and stripe pitch, it is possible to cope with application with a desired stripe width and stripe pitch. Since it is not necessary to modify 2 and 3, it has the advantage that it can be manufactured at low cost. Also, instead of using the shim 5, a plurality of grooves are formed directly on the surface of the one die head half where the slits are formed, and when the pair of die head halves are assembled, a liquid discharge portion and a portion that does not discharge are formed. There is also known a die head configured as described above. This die head has the advantage of good workability, although it is costly because a large number of grooves are machined in the die head half itself with high accuracy. Even in the case of performing striped coating using these die heads, as in the case of performing entire surface coating, in the low viscosity liquid, it is better to narrow the coating gap (distance between the tip of the die head and the substrate) as much as possible. The surface quality is improved and the coating is stable. Therefore, the coating gap is preferably set to 50 to 100 μm in consideration of the swell of the substrate and the running accuracy of the apparatus, and generally considering the safety. It is carried out.

  However, when stripe-like coating is performed using a conventional die head, the stripe width is limited. For example, when the shim 5 is used, it is the limit that the width of the branch portion 5b is 1 mm and the interval between the branch portion 5b and the branch portion 5b is about 1 mm. Therefore, the stripe width is 1 mm and the stripe interval (the uncoated region). The width was about 1 mm. Further, when grooves are formed directly on the die head half, the groove processing is extremely costly, so that very fine groove processing is economically disadvantageous, and the stripe width of 1 mm and the stripe interval of about 1 mm are the limits. It was. For this reason, even if a finer stripe-shaped coating is desired, it cannot be handled.

  The present invention has been made in view of such circumstances, and an object of the present invention is to provide a die head having a simple structure capable of performing extremely fine stripe-shaped coating and a coating method using the die head.

  As a result of various studies to perform coating with a fine stripe width, the present inventors have found the following matters. That is, in a situation where the entire surface is applied with a constant width using a normal die head, when the die head is raised and the coating gap is gradually widened, the coating solution applied in the form of a film breaks and stripes. Depending on the conditions, it becomes a very fine stripe. At this time, the position at which the film-like coating liquid breaks randomly occurs and reproducibility is not observed, but if a groove is formed in the land part at the tip of the die head, the groove becomes a trigger for the coating liquid to break, and the film-like liquid is broken. The coating liquid can be stably and reproducibly divided into stripes at the groove positions. Accordingly, by forming grooves at a desired pitch in the land portion of the die head, it is possible to apply stripes at a desired pitch.

  The present invention has been made on the basis of such knowledge, and the invention according to claim 1 is a die head for applying a coating liquid in a stripe shape, and includes a slit for discharging the coating liquid and both sides of the front end of the slit. The land portion is formed, and a plurality of grooves are formed in at least one of the land portions on both sides of the tip of the slit so as to correspond to the boundary of the stripe formed by the coating liquid.

  The invention according to claim 2 is the invention according to claim 1, wherein the pitch of the plurality of grooves formed in the land portion is 0.5 to 2 mm, and the width of the groove is 0.1 to 0.5 mm. The depth of the groove is 0.1 to 1 mm.

  The invention according to claim 3 forms the groove relative to the substrate to be coated while discharging the coating liquid from the slit of the die head according to claim 1 or 2 with a certain width. The coating method is characterized in that the applied land is moved in a striped manner so that the land portion is located on the rear side.

  According to a fourth aspect of the present invention, in the coating method according to the third aspect, when the discharge of the coating liquid is started, the coating gap between the land portion of the die head and the base material is set to the land portion and the base material. It is characterized in that it is set small so that a bead connected in the coating width direction is formed in between, and after the bead formation, the coating gap is enlarged so that striped coating is performed. is there.

  The die head of the present invention is disposed so as to face the substrate to be coated, and a coating gap between the land portion of the die head and the substrate is arranged in the coating width direction between the land portion and the substrate. In order to form a connected bead, discharge of the coating liquid is started in a small state, and the entire surface of the die head is applied by moving the die head relative to the substrate. By increasing the coating gap by raising, it is possible to divide the coating solution applied in the form of a film at a position corresponding to the groove of the land portion at the tip of the die head and perform striped coating. Thus, a stripe-like coating can be applied at a pitch equal to the pitch of the groove formed in the land portion at the tip of the die head. By setting the groove pitch to 0.5 to 2 mm, the stripe pitch is 0. Application of extremely fine stripes of 5 to 2 mm can be performed. Here, the die head can be manufactured at a low cost because it is sufficient to cut a plurality of grooves at least in the land portion on the side where the coating liquid flows.

  DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, preferred embodiments of the invention shown in the drawings will be described. 1 (a) and 1 (b) are schematic perspective views showing main parts of a coating apparatus provided with a die head according to an embodiment of the present invention during different coating operations, and FIGS. 2 (a) and 2 (b). FIG. 3 is a schematic perspective view showing a part of the die head and the substrate of the coating apparatus shown in FIG. 1 in a state during different coating operations, FIG. 3 is a schematic perspective view showing a part of the die head according to the embodiment of the present invention, 4A is a schematic cross-sectional view of the tip portion of the die head shown in FIG. 1, and FIG. 4B is a schematic perspective view of the tip portion of the die head half. A die head generally indicated by reference numeral 11 is a pair of die head halves 12 and 13 having a structure in which a slit 17 for discharging a coating liquid is formed by facing each other with a bolt (not shown) or the like. Side plates 14 attached to both ends thereof are provided. One die head half 12 is also called a manifold plate, and includes a manifold 16 and a flat slit surface 12a for forming a slit 17 on one side of the manifold 16 (upper side in FIG. 3). A contact surface 12b is provided. The other die head half 13 is also called a flat plate. The entire surface facing the die head half 12 is a flat surface 13a, and the area of the flat surface 13a facing the slit surface 12a of the die head half 12 is a slit surface. A region facing the contact surface 12b is a contact surface. A step corresponding to the gap dimension of the slit 17 is provided on the slit surface 12 a and the contact surface 12 b of the die head half 12. With this configuration, the pair of die head halves 12 and 13 face each other, and the abutting surfaces are abutted and assembled to form a slit 17 having a predetermined gap size. Moreover, since this slit 17 is formed by the flat slit surfaces 12a and 13a, it is the structure which can discharge a coating liquid with uniform thickness from the full width. These structures are the same as the die head used for the conventional full width coating. Instead of providing a slit in the slit surface 12a and the contact surface 12b of the die head half 12 to form a slit, the slit surface 12a and the contact surface 12b are set as the same surface so that the contact between the die head halves 12 and 13 is achieved. A slit 17 having a desired gap dimension may be formed between the die head halves 12 and 13 by sandwiching a shim having a desired thickness between the surfaces.

  The die head halves 12 and 13 are provided with land portions 12c and 13c formed on a plane perpendicular to the slit 17 on both sides of the tip of the slit 17, and a large number of grooves 21 are formed in the land portions 12c and 13c at a constant pitch. Forming. The groove 21 is provided to provide a trigger for separating the coating liquid discharged from the slit 17 into a film shape, and is provided so as to correspond to the boundary of the stripe when performing stripe-shaped coating. . The size of the groove 21 is arbitrary as long as it can give a trigger for separating the coating liquid discharged from the slit 17 into a film shape. 0.5 mm and depth d can be 0.1 to 1 mm. In addition, although the cross-sectional shape of the groove | channel 21 is made into the rectangle in drawing, it is not restricted to this but arbitrary, such as a triangle and a semicircle. In addition, the groove 21 is formed so as to completely cross the land portions 12c and 13c. However, the present invention is not limited to this structure, and only in a partial region of the land portions 12c and 13c (for example, the corner on the side facing the slit 17). (Only part). The pitch p of the grooves 21 is arbitrary, and may be determined so as to be a stripe pitch required when performing striped coating. However, when the stripe width is less than 0.3 mm, the stripe coating is not stable. In addition, if the dimension between stripes (the dimension of the uncoated region) is less than 0.3 mm, adjacent stripes may come into contact with each other, resulting in a reduction in the reproducibility of stripe formation. For this reason, the pitch p is preferably 0.5 mm or more. On the other hand, although there is no upper limit of the pitch p, it is preferable to set the pitch p to about 2 mm or less because the present invention is very effective for coating with a very fine stripe pitch. The gap dimension G of the slit 17 of the die head 11 is preferably 30 to 100 μm, and the width W of the land portions 12c and 13c is preferably about 0.05 to 1 mm.

  As a coating solution for performing striped coating using this die head 11, if the viscosity is too low, a coating film cannot be formed and coating becomes impossible. On the other hand, if the viscosity is too high, the continuous coating film is not broken and striped. Not. Considering these, the coating solution viscosity is preferably about 0.1 to 10 cP. Similarly, the surface tension of the coating solution is preferably about 20 to 30 dyn / cm.

Next, a coating method using the die head 11 having the above configuration will be described. In FIG. 1A and FIG. 2A, the die head 11 is opposed to the upper side of the application start position of the substrate 24 in a state where the substrate 24 such as a glass plate is adsorbed and held on the upper surface of the substrate support 23. Then, the die head 11 is lowered to a position where a coating gap having a minute dimension g ₁ is formed between the die head 11 and the base material 24, and the discharge of the coating liquid is started, and the die head 11 is moved along the base material 24 in the direction of arrow A. Move to. The application gap dimension g _{1 at} this time is set to about 50 to 100 μm so that a bead connected in the application width direction is formed between the land portion of the die head 11 and the substrate 24. By starting application in this state, as shown in FIG. 1A and FIG. 2A, a coating film 25 connected in the application width direction is formed on the base material 24. Next, the die head 11 is moved up in the direction of arrow A to widen the coating gap. In general, the coating gap capable of stably forming the coating film 25 connected in the coating width direction depends on the characteristics of the coating solution, but in the case of a low-viscosity coating solution of about 0.1 to 10 cP, the upper limit is about 150 μm. If the coating gap is further increased, the coating liquid discharged from the die head 11 in a film shape is broken, and a coating film connected in the coating width direction cannot be formed. For this reason, in the case of performing normal whole surface coating, the coating gap is kept to 150 μm or less, but in the present invention, the coating gap is further increased. As a result, the coating liquid discharged from the die head 11 into a film is broken at the position of the groove 21 formed in the land portion of the die head 11, as shown in FIGS. 1B and 2B. In addition, a striped coating film 26 having a cut 27 at a position corresponding to the groove 21 of the die head 11 is formed on the substrate 24. Since the width of the cut line 27 tends to become wider as the coating gap is increased, the cut line 27 is more reliably formed as the coating gap is increased, and the striped coating is stabilized. When the die head 11 is raised to a position where a coating gap (in many cases, gap dimension g ₂ : about 200 to 300 μm) in which the stripe-shaped coating film 26 is stably formed is secured, the die head 11 Then, the application is continued while maintaining the application gap. As described above, stripe-like coating can be performed on the base material 24, and by reducing the pitch of the grooves 21 formed in the land portion of the die head 11, the stripe shape can be formed at a small pitch. Can be applied.

  In the die head 11 according to the above-described embodiment, the grooves 21 are formed in the land portions 12c and 13c on both sides of the slit 17, respectively. However, the grooves 21 are not necessarily provided on both sides of the slit 17, and at least When the die head 11 is moved relative to the base material 24, the die head 11 may be provided on the land portion on the rear side (the side on which the coating liquid flows).

A single wafer die coater shown in FIG. 1 was used. The die head 11 was used for coating the entire surface with a coating width of 350 mm, and grooves 21 having a width of 0.5 mm and a depth of 0.1 mm were formed on the land surfaces 12c and 13c of the die head 11 at a pitch of 1 mm. The liquid supply to the die head 11 was a syringe pump (piping inner diameter 4 mmφ), the substrate 24 was a glass plate, and the coating liquid was an acrylic resin (viscosity: 5 cP).
In order to form an initial bead at the start of coating, the coating gap was set to 50 μm, and the coating gap was set to 200 to 250 μm 0.2 seconds after the start of liquid discharge. As a result, the 350 mm wide connected bead formed at the start of coating is divided at the position of the groove 21, and a striped coating film having a width of 0.5 mm and a pitch of 1 mm is formed on the substrate 24. It was. Application was continued in this state, and when reaching the application end portion, the die head 11 was further raised to set the application gap to 1 mm, and application was completed. As a result, a continuous coating film 25 was formed at the start of coating, but in the subsequent area, a striped coating film 26 was formed up to the end of coating. The stripe height after drying of the coating film was 1.5 μm, and the stripes were formed at equal intervals of 0.5 mm.

  The preferred embodiments and examples of the present invention have been described above, but the present invention is not limited to these embodiments and examples, and can be appropriately changed within the scope of the claims. . For example, in the above embodiment, the case where the stripe-shaped coating is applied to the flat substrate held on the substrate support base 23 has been described. However, the die head of the present invention is not limited to this case, and is a roller. The present invention can also be applied to a case where a stripe-like coating is applied to a web-like substrate being conveyed.

(A), (b) is a schematic perspective view which shows the principal part of the coating device provided with the die head which concerns on embodiment of this invention in the state during different application | coating operation | movement. (A), (b) is a schematic perspective view which shows a part of die head and base material of the coating apparatus shown in FIG. 1 in a state during different coating operations. 1 is a schematic perspective view showing a part of a die head according to an embodiment of the present invention. (A) is schematic sectional drawing of the front-end | tip part of the die head shown in FIG. 1, (b) is schematic perspective view of the front-end | tip part of a die head half body. Schematic perspective view of a conventional die head Disassembled perspective view of main parts of conventional die head

Explanation of symbols

1,11 Die head 2,12 Die head half (manifold plate)
12a Slit surface 12b Abutting surface 12c Land portion 3, 13 Die head half (flat plate)
13a Flat surface (slit surface, contact surface)
13c Land portion 4, 14 Side plate 5 Shim 6, 16 Manifold 7, 17 Slit 21 Groove 23 Base material support base 24 Base material 25 Paint film 26 Striped paint film 27 Cut

Claims (4)

  A die head for applying a coating solution in stripes, comprising a slit for discharging the coating solution, and land portions formed on both sides of the tip of the slit, and at least one of the land portions on both sides of the slit tip A die head characterized in that a plurality of grooves are formed so as to correspond to the boundary of stripes formed with a coating solution.   The pitch of the plurality of grooves formed in the land portion is 0.5 to 2 mm, the groove width is 0.1 to 0.5 mm, and the groove depth is 0.1 to 1 mm. The die head according to claim 1.   While discharging the coating liquid from the slit of the die head according to claim 1 or 2 at a certain width, the land portion where the groove is formed relative to the base material to be coated is on the rear side. And applying the coating solution in stripes.   4. The coating method according to claim 3, wherein a coating gap between the land portion of the die head and the base material is connected in the coating width direction between the land portion and the base material at the start of discharging the coating liquid. The coating method is characterized in that the coating gap is set so as to be small and the coating gap is increased after the bead formation so that striped coating is performed.

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