JP2003039003A - Multi-layer coating device - Google Patents

Abstract

(57) [Summary] [PROBLEMS] To increase the speed, thinning, and uniformity of simultaneous multi-layer coating on a running support so that the coating liquid that should form a layer is not mixed and no streaks are generated. With the goal. A support is continuously guided by a pair of guide rolls separated from each other, and a coating liquid is applied to the support from a coater head provided on the opposite side of the downstream guide roll with respect to the support and between the guide rolls. A coater head comprising an upstream lip portion and a downstream slide lip portion provided with one or more slots, wherein the upstream lip portion and the slot portion formed by the downstream slide lip portion support the coater head. A multi-layer coating apparatus characterized by applying a first layer of coating liquid in contact with the coating liquid and applying another layer of coating liquid from above the downstream slide lip.

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a coating apparatus for performing multi-layer coating on a continuously running support. 2. Description of the Related Art An extrusion hopper type or slide hopper type coating apparatus is capable of high-speed, thin-film, multi-layer simultaneous coating, and is widely used as a coating apparatus for photographic photosensitive materials and magnetic recording materials due to its features. Have been. [0003] As an example of a typical coating method using an extrusion hopper type coater, a support member running continuously on a pair of guide rolls arranged at a fixed interval on the upstream and downstream sides of a coater head is known. Guide me,
There is known a method in which a coating liquid is extruded directly from the coater head disposed between the guide rolls onto the surface of the support to apply the liquid uniformly, smoothly, and thinly. In the case of this method, the coating liquid extruded from the slot of the coater head is pushed by turning the lip portion at the tip of the coater head that extrudes the coating liquid onto a support that continuously runs between a pair of guide rolls. Coating is performed by changing the distance between the lip portion at the tip of the coater head and the surface of the support by the balance between the application pressure corresponding to the amount and the reaction force generated by the support being pressed and bent by the coater head. Is possible. As an application example of the above coating method, when multilayer coating is required for improving performance, simultaneous multilayer coating has been performed by a coater head having a plurality of slots as shown in FIG. . This makes it possible to prevent problems such as inefficiency through the unwinding / rewinding step each time one layer is applied, and peeling of the film generated at that time, partial falling off of the applied film, and cracks. [0005] However, in simultaneous multi-layer coating by the above-mentioned coating method, high speed, thinning,
In order to achieve uniformity, it is necessary to press the coater head against the running support with a high pressure, which may cause a problem in which the coating liquid that should form a layer is mixed. In addition, since the liquid separation of the downstream lip is poor, streaks are easily generated, and the condition area for stable application has been narrowed. Further, in the conventional methods, the influence of the mechanical accuracy is large, and labor is required to secure the accuracy. SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems and to make simultaneous multilayer coating on a running support faster, thinner, and more uniform. According to the present invention, a support is continuously guided by a pair of guide rolls separated from each other, and the support is opposite to the downstream guide roll and between the guide rolls. What is claimed is: 1. A multi-layer coating apparatus for applying a coating liquid to a support from a provided coater head, said coater head comprising an upstream lip portion and a downstream slide lip portion provided with one or more slots, wherein said upstream lip portion and said downstream lip portion are provided. A multi-layer coating apparatus characterized in that a coating liquid of a first layer in contact with a support is applied from a slot formed by a slide lip, and another layer of coating liquid is applied from above a downstream slide lip. [0008] This is because the coating liquid of the first layer in contact with the support can be securely applied to the support by direct application from the slot, and the coating liquid of the second and subsequent layers is applied by a slide. This makes it possible to perform multi-layer coating without pressing the coating liquid of the second and subsequent layers against the coating liquid of the first layer in contact with the support, thereby suppressing mixing between coating layers and preventing troubles such as streaks. I have to. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail below with reference to the drawings. FIG. 1 is a schematic side view showing the configuration of one embodiment of the multilayer coating apparatus of the present invention. The support 21 is supported by guide rolls 11 and 12, and the coater head 1 is disposed in a floating portion therebetween. The support 21 enters from the guide roll 11 side, is coated with the first coating liquid 22 and the second coating liquid 23 at the coater head, and exits via the guide roll 12. The coater head 1 has a lip portion 2 on the upstream side with respect to the support running direction, a slide lip portion 3 on the downstream side, and a manifold provided to supply the coating liquid into the coater head 1 from a supply system (not shown). 5, 6, a slot portion 31, which is a passage for pushing out the first coating solution 22 from the manifold 5 to the lip portion, a slot portion 33, which supplies the second coating solution 23 from the manifold 6 to the slide lip portion, and a slide portion 32. Is done. Each of the manifolds 5 and 6 has a circular or substantially circular cross-section, and extends in the width direction of the support 21 with the same or substantially the same cross-sectional shape. Is longer than or the same length as The inside diameter of manifolds 5 and 6 is 5 to 50 m
The best size may be set in accordance with the properties, viscosity and the like of the coating liquid at about m, and the coating liquid is prevented from leaking to the outside of the coater head 1 at both open ends by sealing plates or the like. The supply of the coating liquid to the manifolds 5 and 6 may be introduced from at least one of the open ends. The first coating liquid 22 is introduced from the outside of the coater head 1 to the manifold 5 via a supply system via a hose or a pipe. When the inside of the manifold 5 is filled with the coating solution, the manifold 5 is surrounded by the upstream lip 2, the downstream slide lip 3, and the support 21 with a uniform pressure distribution and flow rate distribution in the width direction, passing through the slot 31 communicating with the manifold 5. The liquid is applied onto the support 21 while forming the liquid pool 8. The second coating liquid 23 is introduced into the manifold 6 from outside the coater head 1 via a supply system via a hose or a pipe. When the inside of the manifold 6 is filled with the coating liquid, the first coating liquid passes through the slot 33 communicating from the manifold 6 with a uniform pressure distribution and a flow rate distribution in the width direction, passes through the opening after passing through the slide section 32, and passes through the first coating. It is applied in a layer on the liquid. The coating film thickness is determined by the flow rate of the coating liquid to be discharged and the traveling speed of the support. In addition, it is important to form a stable liquid pool 8 for uniform application,
For this purpose, the distance between the support and the lip is determined by the physical properties such as the viscosity of the coating liquid, the discharge pressure of the coating liquid, and the discharge amount of the coating liquid.
It is necessary to optimize the tension applied to the support. The support to be coated includes polyesters such as polyethylene terephthalate and polyethylene-2,6-naphthalate; polyolefins such as polypropylene; cellulose derivatives such as cellulose triacetate and cellulose diacetate; plastics such as polycarbonate; , Al, Zn, etc .;
Synthetic paper is suitable. The thickness is usually about 2 to 300 μm. Regarding the physical properties of the coating liquid, the first coating liquid has a viscosity of 2 to 1000 mPa · s at a liquid temperature of 20 ° C., the coating thickness is 5 to 100 μm, and the second and subsequent coating liquids have a liquid temperature of 20 ° C. Has a viscosity of 2 to 700 mPa · s and a coating thickness of 5 to 100
Coating is possible in the range of μm. At this time, when the viscosity is too high or the coating thickness is too thin, a portion where the coating liquid does not lie on the base material is generated, and the so-called “penetration” occurs.
Occurs, if the viscosity is too low or the coating thickness is too thick, so-called `` sagging '' will occur, which hangs down due to the gravity of the coating solution, but the actual viscosity and coating thickness values are Because it depends on the material of the coating liquid and the coating speed,
Each value must be chosen appropriately. Here, the speeding up which is a problem in the present invention means a coating speed of 300 to 600 m / min.
The present invention shows a greater effect when applied at this application speed. When three or more coating layers are used, FIG.
As shown in the figure, the slide portion 3 of the downstream slide lip 3
2, by providing the slot portions 33 for the number of layers, simultaneous multilayer coating can be performed. <Example> The present invention will be described in more detail with reference to examples. Two-layer coating was performed using the apparatus shown in FIG. A polyester film web having a thickness of 50 μm was used for the support. The composition of the coating solution is as follows. (1) First layer: coating thickness 10 to 15 μm methyl ethyl ketone; 50% epoxy resin; 50% viscosity 200 mPa · s (2) Second layer: coating thickness 10 to 15 μm methyl ethyl ketone; 70% epoxy resin; 30% Viscosity: 20 mPa · s The coating speed was 300 m / min. When coating was performed continuously for 5 hours under the above conditions, no defects such as cracks and streaks occurred, and high-speed, thin-film, and uniform coating were achieved. <Comparative Example> A conventional coater head having two slots in FIG. 3 was used to coat a support held by a backup roll under substantially the same conditions as in the above embodiment. In addition, defects such as layer mixing could not be eliminated. According to the simultaneous multi-layer coating apparatus of the present invention,
Compared with the conventional method, it does not require mechanical precision, can realize high cost of coating by increasing the coating speed, shortening the number of steps, and reduce the mixing of coating liquid between layers, so that the expected film configuration can be reliably performed. It has the following effects. In addition, troubles such as streaks caused by poor liquid separation were improved.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic side view showing the configuration of an embodiment of the multilayer coating apparatus of the present invention. FIG. 2 is a schematic side view showing the configuration of another embodiment of the multilayer coating apparatus of the present invention. FIG. 3 is a schematic side view of a conventional multilayer coating apparatus. [Description of Signs] 1 ... Coater head 2 ... Upstream lip 3 ... Downstream slide lip 5, 6 ... Manifold 8 ... Puddle 11, 12 ... Guide roll 21 ...・ Support 22 ・ ・ ・ First coating liquid 23 ・ ・ ・ Second coating liquid 31, 33 ・ ・ ・ Slot part 32 ・ ・ ・ Slide part 102 ・ ・ ・ Downstream lip

Claims (1)

Claims: 1. A supporter is continuously guided by a pair of guide rolls separated from each other, and a coater head provided on the opposite side of the downstream guide roll with respect to the supporter and between the guide rolls. A multilayer coating apparatus for applying a coating solution to a support, wherein the coater head includes an upstream lip portion and a downstream slide lip portion provided with one or more slots, and is formed by the upstream lip portion and the downstream slide lip portion. A multi-layer coating apparatus, which applies a first layer coating solution in contact with a support from a slot portion to be formed, and applies a coating solution of another layer from a downstream slide lip portion.