JP2006326421A - Coating apparatus and coating method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a coating apparatus constituted so that a continuously traveling web-like base material is coated with a coating solution by an extrusion type coating head, the coating solution is circulated without being discharged from the slit opening part of the coating head during a coating standby period and the adjustment of the viscosity or the like of the coating solution is dispensed with at the time of resumption of coating, and a coating method. <P>SOLUTION: In the coating apparatus constituted so as to coat the continuously traveling web-like base material with the coating solution by the extrusion type coating head, the coating head is equipped with a means for setting a coating head moving means to an arbitrary position between a coating position and a retracted position and the roll or bar provided on the moving locus of the coating head due to the moving means and made possible to move and arrange so as to hermetically close and open the slit aperture part provided to the lip leading end of the coating head. An elastic member is applied and laminated to the outside surface of the roll bar. The coating method is also disclosed. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

The present invention relates to a coating apparatus and a coating method using an extrusion type coating head for uniformly coating a coating liquid on a continuously running web-like substrate. More specifically, the present invention relates to a coating apparatus and a coating method in which a coating liquid is laminated on a thin film on a flexible base material such as plastic, paper, and metal, and uniformly coated to form a highly functional film.

Conventionally, when a functional optical film, a photographic light-sensitive material, a magnetic recording medium, a steel plate surface treatment, and the like are produced, there is a step of applying a coating solution onto a substrate.

  Further, in the coating solution, essential components such as a photosensitive material or magnetic particles are mixed with a resin binder, and various additives are added as necessary. And it is used by diluting with an organic solvent or the like to adjust the viscosity.

  In addition, as a method for applying the coating liquid to the substrate, for example, various coating methods such as a roll coater, a gravure coater, a knife coater, an extrusion coater, and various reverse coaters are used.

  Among the coating methods, the extrusion type coater is excellent in the uniformity in the width direction of the coating film, and is excellent in the smoothness of the coating surface. In recent years, its use has increased.

  In addition, the extrusion type coater does not expose the coating solution to air until immediately before coating, and changes in the properties of the coating solution are very small. Therefore, stable management of the performance of the coating film is easy. Furthermore, since the coating solution is basically a method in which only a required amount is applied and applied, the improvement effect is greater than other methods in terms of cost and manufacturing environment.

  However, the coating liquid is continuously discharged from the slit even when the coating is not performed, and the liquid is made waste, or the coating liquid 102 discharged from the slit 101 is received by the liquid receiving pan 103 as shown in FIG. Many coating apparatuses 100 that are used by returning to the liquid tank 106 are also used.

  Further, as shown in FIG. 5, a coating apparatus 200 that receives a coating liquid 110 discharged from a slit 111 below a coating head 300 of an extrusion type coater 300 by a suction guide 108 and circulates by a pump 109 (see, for example, Patent Document 1). ) Is also known.

Prior art documents are shown below.
JP 2002-301417 A

  The extrusion coater is used to apply a coating solution in a manifold of a coating head when coating a substrate using a coating solution in which particles are dispersed or a coating solution composed of a resin binder or a solvent having poor compatibility. To separate. For this reason, there is a problem that uniform discharge cannot be performed from the slit.

And the thickness of a coating film becomes non-uniform | heterogenous or the distribution of the component in a coating film arises unevenly. Moreover, it is difficult to obtain the performance as designed. Furthermore, there is a problem that the coating itself cannot be normally performed, and the occurrence of missing or vertical stripes occurs.

  As a countermeasure, the application liquid is continuously discharged from the slit even when the application is not performed, or the application liquid is circulated by a pump or the like from a liquid receiving pan or a suction guide. And it suppresses that a coating liquid phase-separates.

  However, there is a problem that the coating liquid is lost if the coating liquid is continuously discharged from the slit during the coating standby. Further, when the material is recovered and reused, the viscosity, components, and the like change. And readjustment of a coating liquid is needed.

  Further, when the coating liquid is continuously passed through the manifold, air enters the interior and the coating liquid dries unless the manifold is pressurized. And a foreign material generate | occur | produces and a stripe etc. generate | occur | produce.

  Furthermore, in the case of stirring in the manifold, there is a problem that the structure of the apparatus is complicated, and the operation of the application work after application standby is complicated and takes time. Furthermore, maintenance is difficult.

  Further, when using a coating liquid that is easy to separate, the coating apparatus must be frequently stopped to disassemble and clean the coating head. For this reason, there has been a problem that the production efficiency is remarkably lowered.

  The present invention has been made in view of the above-described conventional problems. When coating using an extrusion type coating head, the coating liquid is not wasted, and it is a simple method and can be used in a simple manner. There are no streaks. And it is a coating device that can achieve the performance as designed.

  In addition, even after waiting for coating, uniform and stable coating can be performed immediately without readjusting the coating liquid, disassembling the coating head, and performing cleaning.

  And it is providing the coating device and the coating method which can suppress the isolation | separation and modification | denaturation of the coating liquid in a manifold, and can achieve the stable continuous production.

In order to solve the above problems, the invention according to claim 1 of the present invention provides:
A coating apparatus that applies a coating solution to a continuously running web-shaped substrate with an extrusion type coating head,
The coating head includes a coating head moving unit and a unit for arbitrarily setting a position between a coating position and a retracted position,
A roll or bar capable of moving and disposing the lip tip slit opening of the coating head tightly on the movement trajectory of the coating head by the moving means;
The coating apparatus is characterized in that an elastic member is coated and laminated on the outer surface of the roll or bar.

Next, the invention according to claim 2 of the present invention is as follows:
2. The coating apparatus according to claim 1, wherein at least one coating liquid inlet and outlet is provided at a central portion or an end of a manifold formed in the coating head.

In the invention according to claim 3 of the present invention, the waviness in the lip tip width direction of the coating head is 0.
The coating apparatus according to claim 1 or 2, wherein the width of the roll or the bar is 0.030 mm or less, and the thickness of the elastic member is 0.050 mm or more. .

  Next, the invention according to claim 4 of the present invention is characterized in that the roll or bar is iron, stainless steel, other various alloys, or a member obtained by plating the surface of the steel material. The coating apparatus according to claim 2 and claim 3.

  The invention according to claim 5 of the present invention is the coating apparatus according to any one of claims 1 to 4, wherein the roll or bar is placed on the movement locus of the lip tip slit opening of the coating head during coating standby, and coating is performed. The distance h between the head and the roll or bar satisfies 0 <h <elastic member thickness, and is placed in close contact with the position where the coating head and elastic member are in close contact, and the coating liquid continues to flow in the coating head. Is the method.

  The coating apparatus and the coating method of the present invention can stably and continuously produce a coating liquid in which particles are dispersed and a coating liquid such as a resin binder or a solvent having poor compatibility, while suppressing separation and modification.

  In addition, the performance as designed can be obtained by a simple method without wasting the coating liquid and without occurrence of leakage or vertical stripes.

  Application work after application standby is easy and can be resumed in a short time. In addition, there is no denaturation or separation within the manifold of the coating head. And application processing can be performed with high production efficiency.

  A coating apparatus and a coating method of the present invention will be described in detail along with embodiments with reference to the drawings. 1 to 3 show an embodiment of the present invention.

  FIG. 1 is a schematic view showing an outline of an embodiment of an extrusion type coating head used in the coating apparatus of the present invention. 2 is a schematic cross-sectional view showing a schematic cross-section of the plane of FIG. Further, FIG. 3 is an explanatory diagram for explaining the outline of applying the coating liquid to the substrate with the coating head.

  As shown in FIG. 1 or FIG. 2, the coating liquid 2 charged into the coating liquid storage tank 1 is sent to the coating head 4 from the central inlet 7 by a pump 3.

  Then, after being fed into the manifold 5 from the inflow port 7 at the center, it is discharged from the slit opening 9 as shown in FIG. Then, the coating liquid 2 is applied to the base material 11 running on the backup roll 10.

  Further, when the coating liquid 2 is applied to the base material 11, the roll 12 on which the elastic member 13 is coated and moved moves upward of the backup roll 10.

  The coating head 4 is formed of a manifold 5, a slit 6, an inlet 7 and an outlet 8, and the manifold 5 and the slit 6 are connected. The coating liquid flow path is provided inside, and the coating liquid 2 is fed into the manifold 5 from the end 7 or the central inlet 7 of the coating head 4.

The manifold 6 has a substantially semicircular cross-sectional shape in the transport direction of the base material 11 to which the coating liquid 2 is applied. Further, the same direction as the width direction of the base material 11 is a space extending in a horizontally long shape having the same or substantially the same shape as the cross-sectional shape.

  The inner diameter formed in the substantially semicircular shape is about 5 to 50 mm, and is set to the best size according to the properties, viscosity and the like of the coating liquid 2. Further, although not shown in the drawing, both ends thereof are blocked by a sealing plate or the like so that the coating liquid 2 does not leak outside the coating head 4.

  Moreover, the width | variety opened toward the base material 11 from the manifold 5 is a slit-shaped coating liquid channel | path of 0.05-0.5 mm. Furthermore, the distance from the manifold 5 to the slit opening 9 is about 5 to 100 mm.

  Further, the width and distance of the slit 6 are appropriately determined depending on the properties of the coating solution or various conditions such as the coating speed and the coating film thickness.

  Further, as the elastic member 13 which is disposed between the backup roll 10 and the coating head 4 and can be moved and arranged, the roll 12 or the bar is covered and laminated, for example, fluororesin, ethylene propylene rubber, nitrile rubber, polyethylene A terephthalate resin etc. are mentioned.

  As shown in FIG. 1 or FIG. 2, at the time of application standby, the roll 12 or the bar (not shown) is moved on the movement locus of the backup roll 10 and the slit opening 9 of the application head 4.

  Further, the coating head is brought close to the roll 12 or the bar, and the distance h between the roll surface or the bar and the lip tip satisfies the relationship 0 <h <roll. And the flow path to the exterior of the coating head 4 of the coating liquid 2 is interrupted | blocked by arrange | positioning so that the coating head 4 and the roll 12 or bar may contact | adhere.

  At the same time as the tip of the lip is cut off, an outlet 8 communicating with the manifold 5 is opened, and the coating liquid is circulated in the manifold by the pump without flowing out.

  The above invention will be described more specifically with reference to examples.

<Example 1>
The coating liquid is a compound that generates radicals when irradiated with active energy such as ultraviolet rays, 10 parts by weight of fine particles made of an acrylic styrene copolymer with respect to 100 parts by weight of a compound having a (meth) acryloyl group in the molecule. 3 parts by weight was prepared, and an antiglare hard coat material adjusted to a solid content concentration of 50% with ethyl acetate was prepared and used.

  Further, a triacetyl cellulose film having a thickness of 80 μm was used as the substrate to be coated.

  And with the coating device of this invention, it apply | coated for 100 minutes so that it might become a wet film thickness of 10 micrometers at the speed | rate of application | coating width 1000mm and 40 m / min.

  Thereafter, during the coating waiting time of 30 minutes, the coating head was brought close to a roll having a diameter of 120 mm on which PTFE having a thickness of 1 mm was coated and laminated. Further, the distance between the lip tip and the surface of the roll was set to 0.9 mm, and the lip tip slit opening and the roll were brought into close contact with each other.

  Then, the flow of the coating liquid passing through the manifold was continued by operating the pump. Thereafter, the roll was retracted and the coating operation was resumed under the same conditions as described above.

  As a result, no abnormality was found in the film thickness and Haze, and a good coating state was obtained.

  Furthermore, the application head was disassembled and the inside of the manifold was observed, but no abnormality was confirmed.

<Comparative example 1>
Using the same coating solution as in Example 1, coating was performed under the same conditions, and then a coating standby time of 30 minutes was taken. During that time, the pump was stopped. Thereafter, application was resumed.

  As a result, no significant change was observed in the film thickness before standby, but a distribution in the width direction was confirmed in Haze.

  When the coating head was disassembled and the inside of the manifold was observed to elucidate the cause, it was confirmed that sedimentation of fine particles increased as the distance from the coating solution supply port increased.

  As described above, in the coating apparatus and the coating method of the present invention, the coating solution is not denatured and separated in the manifold. Further, even when the application is interrupted, the application can be restarted quickly and stably.

  The coating apparatus and coating method of the present invention not only enables precise coating of optical films, electronic substrates, food packaging materials, etc., but also is excellent in coating processing operations after coating standby, etc. It is a wonderful invention that can be used in a wide range of fields such as parts for precision instruments and electrical / electronic parts.

It is the schematic which shows the outline of one Example of the extrusion type coating head used for the coating device of this invention. It is a cross-sectional schematic diagram which shows the schematic cross section of the plane of FIG. It is explanatory drawing for demonstrating the outline which apply | coats a coating liquid to a base material with a coating head. It is a schematic explanatory drawing for demonstrating the state at the time of the coating standby of the conventional coating device. It is a schematic explanatory drawing for demonstrating the state at the time of the coating standby of the conventional coating device.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Coating liquid storage tank 2 ... Coating liquid 3 ... Pump 4 ... Coating head 5 ... Manifold 6 ... Slit 7 ... Inlet 8 ... Outlet 9 ... Slit opening 10 ... Backup roll 11 ... Base material 12 ... Roll or bar 13 ... Elastic member 14 ... Moving head for application head

Claims (5)

A coating apparatus that applies a coating solution to a continuously running web-shaped substrate with an extrusion type coating head,
The coating head includes a coating head moving unit and a unit for arbitrarily setting a position between a coating position and a retracted position,
A roll or bar capable of moving and disposing the lip tip slit opening of the coating head tightly on the movement trajectory of the coating head by the moving means;
An applicator characterized in that an elastic member is coated and laminated on the outer surface of the roll or bar.   The coating apparatus according to claim 1, wherein at least one coating liquid inflow port and at least one outflow port are provided at a central portion or an end portion of a manifold formed in the coating head.   The waviness in the width direction of the lip tip of the coating head is 0.010 mm or less, the waviness in the width direction of the roll or bar is 0.030 mm or less, and the thickness of the elastic member is 0.050 mm or more. Claim | item 1 and the coating device of Claim 2.   4. The coating apparatus according to claim 1, wherein the roll or bar is iron, stainless steel, other various alloys, or a member obtained by plating the surface of the steel material.   5. The coating apparatus according to claim 1, wherein a roll or a bar is arranged on a movement locus of a lip end slit opening of the coating head during coating standby, and a distance h between the coating head and the roll or bar is 0 < h <elastic member thickness, satisfy | fills, arrange | positions in the position where an application head and an elastic member closely_contact | adhere, and continues flowing the coating liquid in an application head, The coating method characterized by the above-mentioned.

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