JPH0418912B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a coating device. In particular, in the production of photosensitive printing plates for photographic light-sensitive materials such as photographic film and photographic paper, recording materials such as magnetic recording materials such as magnetic recording tape, and pressure-sensitive copying materials, continuously running long strip supports (hereinafter referred to as (referred to as the "web").
The present invention relates to an apparatus for applying a coating liquid such as a photographic emulsion or a magnetic agent to a surface. More specifically, the present invention relates to an apparatus for coating a thin film of coating liquid by colliding it with a traveling belt-shaped support.

Among the methods in which a thin film-like coating liquid is applied by colliding with a traveling belt-like support, a typical method is the curtain coating method.

[Prior art]

The curtain coating method is a method in which a free-falling curtain made of one or more coating liquids is formed, and the curtain is collided with the object to be coated to form a coating film on the object. However, due to the demand for improved coating quality, high-precision coating is gradually required, and in recent years, it has been disclosed in Japanese Patent Publication Nos. 49-24133 and 49-35447. Attempts have also been made to apply curtain coating methods to fields that require particularly high precision, such as the production of photographic materials.

The method disclosed in Japanese Patent Publication Nos. 49-24133 and 49-35448 involves applying one or more types of coating liquid to two supporting members (hereinafter referred to as "Etsuji Guide"
That's what it means. ) to form a thin, free-falling curtain that is applied to a continuously running web.

In this coating method, as shown in Japanese Patent Publication Nos. 49-24133 and 49-35447, in order to apply the coating liquid to the web, the formed film is received by a deflector and the liquid is transferred to a tray before the coating process starts. A method is known in which the film is allowed to flow and then, when the coating operation starts, a deflector is rotated or slid to cause the film to fall onto the web.

However, this application method requires extra movable parts on the front of the coater, complicates the equipment, has poor operability on the work surface, and also requires space when the curtain film must be lowered. There are drawbacks that make it difficult.

[Purpose of the invention]

An object of the present invention is to provide a simple coating device that does not have a moving mechanism such as rotation or sliding in the coater, and is capable of coating even curtains with a low film height.

[Structure and operation of the invention]

The above object of the present invention has first and second cavities and first and second slots of narrowly elongated width, the second cavity being connected to the first through the second slot.
A liquid injector is connected to the cavity, and the first slot is structured to guide the coating liquid from the first cavity to the outside, and the first and second liquid supply devices are connected to the first and second cavities, respectively. This is achieved by a coating device consisting of a tube and first and second liquid pumps.

Hereinafter, the content of the present invention will be explained in more detail based on the drawings.

Fig. 1 is a side view of the present invention applied to a curtain coating method using an extrusion hopper having a single-layer sliding portion, and Fig. 2 is a side view of the case of applying the present invention to a two-layer curtain coating method. This is a diagram.

When the first liquid feeding pump 11 is also used for regular coating, the second liquid feeding pump 12 is used only when the flow rate increases, and a pump that is normally larger than 11 is selected as the pump 12.

In FIG. 1, when starting the coating operation, the coating liquid is transferred from the liquid tank 13 to the first liquid supply pipe 9 and the second liquid supply pipe using the first liquid supply pump 11 and the second liquid supply pump 12. 10 through the first cavity 4 and the second cavity
is sent to cavity 5 of

After the coating liquid sent by the second liquid sending pump 12 passes through the second cavity 5, the second
The liquid enters the first cavity 4 through the slot 7 of the liquid injector 1, where it joins with the coating liquid fed by the first liquid feed pump 11, passes through the first slot 6 with a narrow and elongated width, and enters the liquid injector 1. It flows down the sliding slope 16 as a falling layer 8, forms a thin film 18 from the lip 15, and collides with the web 19, forming a coating film 17. 2,3
14 is a pass roller, and 14 is a support bar that guides both ends of the thin film 18, which is held by a frame 25.

When a large amount of liquid is required to be delivered, such as when starting up a coating operation, in addition to the first liquid sending pump 11, which always sends liquid at a constant rate, the second liquid sending pump 12 is used in combination to quickly transfer a large amount of coating liquid. A film is formed instantly by flowing the water for a period of time, preferably 1 to 3 seconds.

In order to minimize the increase in liquid volume at the start, the slot and cavity should be
It is necessary to improve the width distribution by passing the liquid twice, and usually the second liquid feeding pump 12 is passed through the first
It is preferable to use a pump with a smaller flow rate than the liquid feeding pump 11 and use it as a temporary liquid feeding pump for starting, but in order to shorten the transient time when the flow rate increases, the second liquid feeding pump is used as the first liquid feeding pump. It can also be used as a pump with a larger flow rate than the liquid sending pump 11.

Furthermore, although there is no particular restriction on the relative size of the cavities 4 and 5, when the second liquid pump 12 is used as a large flow pump, the second cavity 5 is usually made larger than the first cavity 4. be.

In addition, the first liquid feeding pump 11 and the second liquid feeding pump 1
The method of connecting the two liquid tanks 13 to the liquid tank 13 is shown in the diagram in which each is connected by a separate liquid supply pipe, but the pipes are connected in the middle to form one pipe, and there is only one suction port from the liquid tank. Of course you can.

FIGS. 2 and 3 are conceptual side views when performing two-layer coating using the apparatus of the present invention. As in FIG. The first coating liquid is fed at a constant rate to the first cavity 4 through the liquid pipe 9, and is led to the outside through the narrowly extended first slot 6 and flows down on the inclined surface 16. 3. The third liquid supply pipe 21 is supplied from another storage tank 23 by the liquid supply pump 22.
The second coating liquid is sent to the third cavity 24 through the third slot 20 having a narrow and elongated width, is guided to the outside, flows down on the slope 16 and joins, forming the multilayer flow lower layer 8 and forming the lip 15. The multilayer thin film 18 collides with the web 19 to form a multilayer coating film 19. In transient conditions such as when starting coating or passing through a bond, the second liquid feeding pump 12 pumps the storage tank 13.
The first coating liquid is fed into the second cavity 5 through the second liquid supply pipe 10, and is connected to the first cavity 4 through the second slot 7 having a narrow and elongated width, so that the liquid exceeds the above-mentioned certain ratio. A temporary coating operation is performed by feeding the liquid.

4 and 5 are side views showing the concept of the device of the present invention when an extrusion type liquid injection device is used, and since the content is almost the same as that of FIGS. 1 and 3, explanation will be given below. is omitted.

1 to 5 all show the structure of the apparatus of the present invention. That is, both have first and second cavities 4, 5 and first and second slots 6, 7 having narrowly extended widths, and the second cavity 5 is connected to the second cavity through the second slot 7. The first slot 6 is connected to the first cavity 4, and the first slot 6 is connected to the liquid injector 1 which guides the coating liquid from the first cavity 4 to the outside, and the first and second cavities 4 and 5 connected to the first cavity 4 and the second cavity 5, respectively. 2 liquid supply pipes 9, 10 and first and second liquid feeding pumps 11, 12
It is a coating device consisting of. These apparatuses of the present invention are not only effective in transient conditions such as the above-mentioned time of starting coating and passing through bonding, but also have the effect of uniformizing coating and preventing stagnation of the coating liquid.

FIGS. 6 and 7 are side views of an embodiment based on a different concept from FIGS. 2 and 3, respectively, when two-layer coating is performed using the apparatus of the present invention. In FIG. 6, during the coating operation, the first coating liquid is fed at a constant rate from the storage tank 43 to the first cavity 34 through the first liquid feeding pump 39 by the first liquid feeding pump 41, and the first coating liquid is spread over a narrowly extended width. The liquid is guided to the outside through the first slot 35 and flows down the slope 46, but at the same time, the third liquid is sent from another storage tank 51 to the second cavity 36 through the third liquid supply pipe 52 by the third liquid sending pump 44. 2
The coating liquid is guided to the outside through the second slot 37 having a narrow and extended width, flows down on the slope 46 and joins to form a multilayer flow lower layer 38, and from the lip 45, it becomes a multilayer thin film 48 and collides with the web 49. Multilayer coating 4
7 is formed. 32, 33 are pass rollers, 46
are held by a frame 50 by support bars that guide both ends of the thin film 48. In a transient state such as when starting coating or passing through a joint, the second liquid supply pump 42 moves the liquid from the storage tank 43 to the second liquid supply pipe 40.
The first coating liquid is fed into the first cavity 4 through the first cavity 4, and a transient coating operation is performed by feeding the liquid in excess of the above-mentioned certain ratio.

In FIG. 7, during coating work, a first liquid is sent from a storage tank 73 to a first cavity 64 at a constant rate through a first liquid sending pipe 69 by a first liquid sending pump 71.
The first slot 66, 6 has a narrow and elongated width.
1 and flow down the slope 76,
At the same time, the second coating liquid is sent from another storage tank 83 to the third cavity 79 through the third liquid supply pipe 82 by the third liquid sending pump 82 and is guided to the outside through the third slot 80 having a narrow and extended width. They flow down on the slope 76 and merge, forming a multi-layer lower layer 68 and forming a lip 84.
The web 79 collides with the multilayer thin film 78 to form a multilayer coating film 77. Pass rollers 62 and 63 are supported by a frame 75, and support bars 74 guide both ends of the thin film 78. In a transient state such as when starting coating or passing through a bond, the first coating liquid is fed from the storage tank 73 to the second cavity 65 through the second liquid supply pipe 70 by the second liquid feeding pump 72, and the second cavity 65 is further narrowed. Second slot 67 with extended width
The liquid flows through the liquid into the first slot 61, and the liquid is fed in excess of the above-mentioned certain ratio to perform a transient coating operation.

The web used in the present invention includes paper, plastic film, metal, resin coated paper, synthetic paper, and the like. The material of the plastic film includes, for example, polyolefins such as polyethylene and polypropylene, vinyl polymers such as polyvinyl acetate, polyvinyl chloride, and polystyrene;
Polyamides such as 6,6-nylon and 6-nylon, polyesters such as polyethylene terephthalate and polyethylene-2,6-naphthalate, polycarbonates, and cellulose acetates such as cellulose triacetate and cellulose diacetate are used. Further, the resin used for resin coated paper is typically polyolefin such as polyethylene, but is not necessarily limited thereto. Further, as the metal web, for example, there is an aluminum web.

Furthermore, the term "coating liquid" includes liquid compositions of various types depending on the application, for example, coating of light-sensitive emulsion layers, undercoat layers, protective layers, back layers, etc. in photographic light-sensitive materials. Liquid: Coating liquid for magnetic layer, undercoat layer, lubricating layer, protective layer, backing layer, etc., as in magnetic recording media; Coating liquid for adhesive layer, colored layer, rust prevention layer, etc. These coating solutions contain a water-soluble binder or an organic binder.

〔Example〕

In order to further clarify the effects of the present invention, examples will be introduced below.

Example 1 A liquid having the following composition and a viscosity of 13 cps was applied using the apparatus shown in FIG.

Acrylic acid polymer: 5 parts by weight Methyl glycol: 70 parts by weight Methyl ethyl ketone: 25 parts by weight Fluorine surfactant: 0.2 parts by weight A polyethylene terephthalate film with a thickness of 100 μm was used as the web 19 and was run at a speed of 80 m/min. 11, the liquid was fed so that the coating width was 100 cm and the coating amount was ³⁰ c.c./m2, and the liquid was fed at a flow rate of 560.0 cc/min using the second liquid feeding pump 12 for 3 seconds only at the start, and a good curtain film was obtained. It was able to be formed immediately, and the coating work started smoothly.

Example 2 (1) The following first coating liquid A and second coating liquid B were prepared.

First coating liquid A A liquid with the following composition and a viscosity of 13 cps Acrylic acid polymer 5 parts by weight Methyl glycol 70 parts by weight Methyl ethyl ketone 25 parts by weight Fluorine surfactant 0.1 part by weight Second coating liquid B A liquid with the following composition and a viscosity of 20 cps Acrylic Acid polymer: 8 parts by weight Methyl glycol: 68 parts by weight Methyl ethyl ketone: 24 parts by weight Fluorine surfactant: 0.5 parts by weight (2) In Fig. 2, a polyethylene terephthalate film with a thickness of 100μ is used as the web 19 and is run at a speed of 8 m/min. and the first liquid feeding pump 11
The first coating liquid A is fed so that the coating width is 100 cm and the coating amount is ²⁰ c.c./m2, and the third liquid feeding pump 22
The second coating solution B was fed so that the coating width was 100 cm and the coating amount was 10 c.c./m ² . Only at the start 2
When the first coating liquid A was fed at a flow rate of 5000 c.c./min by the second liquid feeding pump 22, a good curtain film was instantly formed, and the coating operation could be smoothly started.

〔Effect of the invention〕

According to the present invention, application, bonding, etc. in curtain coating can be performed using a simple mechanism in which the coater does not require a moving mechanism such as rotation or sliding. Further, as mentioned above, since there is no moving mechanism, it can be applied to curtain coats with a low film height.

Moreover, the present invention can be widely applied in addition to the embodiments described in the embodiments and drawings.

[Brief explanation of drawings]

1 to 5 are side views conceptually showing the device of the present invention, and FIGS. 6 and 7 are side views conceptually showing other embodiments of the device of the present invention. 1... Liquid injection device, 4... First cavity, 5... Second cavity, 6... First slot, 7... Second slot,
9...first liquid supply pipe, 10...second liquid supply pipe, 11,
41, 71...first liquid feeding pump, 12, 42, 72
...Second liquid feeding pump, 18, 48, 78... Thin film coating liquid, 19, 49, 79... Web.

Claims (1)

[Claims] 1. In an apparatus in which a coating liquid is sent to a liquid injection device through a liquid supply pipe by a liquid feeding pump, and the coating liquid is applied in the form of a thin film from the liquid injection device by colliding with a traveling band-shaped support, the liquid injection device has first and second cavities and first and second narrowly elongated width slots;
The second cavity is connected to the first cavity through a second slot, and the first slot has a structure that guides the coating liquid from the first cavity to the outside, and the liquid supply pipe and the liquid pump are connected to each other. A coating device comprising first and second liquid supply pipes connected to first and second cavities, respectively, and first and second liquid feeding pumps.