JP2000000513A - Method for supplying auxiliary liquid for curtain flow coating - Google Patents

Abstract

PROBLEM TO BE SOLVED: To eliminate stagnation of an auxiliary liquid and thickening flow coating thickness at the selvage parts in curtain flow coating and to provide curtain coating with highly uniform and excellent quality at high productivity by eliminating voids by keeping the dissolved gas not higher than the saturation amount and preventing the film-like stain adhering to the inside of a pipe by installing a sterilization apparatus. SOLUTION: This method is for supplying an auxiliary liquid during curtain coating carried out by running a coating liquid in a slide face 2 out of a coating liquid supply slit 3 of a coating apparatus 1 and at the same time running an auxiliary liquid out of liquid pouring ports 6 of side plates 5 formed in both sides of a slide face 2, forming a curtain film by an edge guide 4 from a lip at the terminal end of the slide face 2, and hitting the curtain film against a transported supporting body. The amount of the dissolved gas at the supply outlets of the auxiliary liquid, which are the pouring ports 6 of the side plates, is kept in unsaturated state and the inside of a supply system including supply routes of the curtain flow coating assisting liquid is sterilized by installing a sterilization apparatus 41 in the supply system.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for supplying an auxiliary liquid in curtain coating using an auxiliary liquid as a side liquid. In particular, it relates to long-term stable and continuous supply of a small amount of auxiliary liquid.

[0002]

2. Description of the Related Art Flowing an auxiliary liquid in a curtain coating method is effective in improving the coating property of a side portion and reducing a thick film, and various companies have filed many patent applications as follows.

[0003] JP-A-1-199668, JP-A-54-1979
73365, JP-A-5-293429, JP-A-5959
JP-A-132966, JP-A-50-88138, JP-A-59-132966, JP-A-3-500858 and JP-A-63-287574.

All of these patents use an auxiliary liquid, and as a result, it can be seen that the thickness of the side portion is reduced as shown in FIG. 4 and uniform application in the width direction is achieved. Long-term stable application was difficult to maintain. It can be said that stability is not taken into account.

[0005]

SUMMARY OF THE INVENTION The present invention solves such disadvantages in curtain coating, and supplies a curtain coating auxiliary liquid for stably performing coating with a uniform thickness in the width direction for a long time. The task is to provide a method.

[0006]

As a result of the study, the present inventors have found that if the conventional auxiliary liquid supply technology in curtain coating as described above is used for a long time, problems such as generation of bubbles and generation of bacteria occur. We have found that this leads to the aforementioned poor sustainability.

That is, the growth of bubbles causes flow hunting and interruption of the supply of the auxiliary liquid, and the generation of bacteria causes film-like dirt in the pipes. It has been found that this may cause a failure of the flat valve 62 which is a control valve. In either case, the flow rate of the auxiliary liquid is destabilized, causing the destabilization of the curtain film, deteriorating the applicability of the side part, or causing poor drying due to the thick film, and in the worst case, The production process must be stopped, which leads to a decrease in production efficiency.

An object of the present invention is to solve such a problem, specifically, to suppress the generation of bubbles and to suppress the generation of film-like foreign matter.

This object is achieved by the following technical means (1) to (13):
Is achieved by any of the following.

(1) The coating liquid flows out from the coating liquid supply slit of the coating apparatus to the slide surface, and the auxiliary liquid flows out from the liquid inlets of the side plates provided on both sides of the slide surface. A curtain film formed by an edge guide from an end lip, and a method for supplying the auxiliary liquid in curtain coating in which the curtain film collides with a conveyed support to apply the curtain film; Wherein the dissolved gas amount of the auxiliary liquid at the auxiliary liquid supply outlet is set to an unsaturated state.

(2) The coating liquid flows out from the coating liquid supply slit of the coating apparatus to the slide surface, and the auxiliary liquid flows out from the injection holes of the side plates provided on both sides of the slide surface. A curtain film is formed from an edge lip by an edge guide, and the curtain film is collided with a conveyed support to apply the curtain film. A method for supplying a curtain coating auxiliary liquid, wherein a sterilizing device is provided in the system to sterilize the auxiliary liquid in the system.

(3) The coating liquid is caused to flow out of the coating liquid supply slit of the coating apparatus to the slide surface, and the auxiliary liquid is caused to flow out of the injection holes of the side plates provided on both sides of the slide surface. A curtain film formed by an edge guide from an end lip, and a method for supplying the auxiliary liquid in curtain coating in which the curtain film collides with a conveyed support to apply the curtain film; The amount of dissolved gas in the auxiliary liquid at the supply outlet of the auxiliary liquid is set to an unsaturated state, and a sterilizer is provided in the curtain coating auxiliary liquid supply system to sterilize the auxiliary liquid in the system. And a curtain coating auxiliary liquid supply method.

(4) The coating liquid is caused to flow out from the coating liquid supply slit of the coating apparatus to the slide surface, and the auxiliary liquid is caused to flow out from the injection holes of the side plates provided on both sides of the slide surface. A method for supplying the auxiliary liquid in curtain coating in which a curtain film is formed by an edge guide from an end lip and is applied by colliding the curtain film onto a conveyed support, wherein the auxiliary film is supplied from a pot for supplying an auxiliary liquid. A curtain coating auxiliary liquid supply method, wherein the auxiliary liquid is continuously degassed and / or sterilized until the supply outlet.

(5) The flow rate of the auxiliary liquid is 0.5% on one side.
(1) to 3 cc / min.
(4) The method for supplying a curtain coating auxiliary liquid according to any one of the above (4).

(6) The method for supplying a curtain coating auxiliary liquid according to the item (5), wherein the flow rate of the auxiliary liquid is measured by a thermal mass flow meter.

(7) The method according to (5) or (6), wherein the flow rate of the auxiliary liquid is controlled using a flat valve.

(8) The curtain coating auxiliary liquid according to any one of (1) to (7), wherein a deaerator is provided in the curtain coating auxiliary liquid supply system to perform degassing. Supply method.

(9) The method for supplying a curtain coating auxiliary liquid according to the item (8), wherein feedback is applied to the deaerator while monitoring the dissolved oxygen amount of the auxiliary liquid.

(10) A filter is provided between the sterilizer and the flow meter for sterilization.
(7) The method for supplying a curtain coating auxiliary liquid according to any one of the above (7).

(11) The method for supplying a curtain coating auxiliary liquid according to the item (10), wherein the filter is provided immediately after the sterilizer.

(12) The method for supplying a curtain coating auxiliary liquid according to the item (10), wherein a filter different from the filter is provided immediately before the flow meter.

(13) The method according to any one of (1) to (12), wherein the coating liquid is a coating liquid containing gelatin.

It is desirable that the dissolved gas of the auxiliary liquid be in an unsaturated state in the entire auxiliary liquid supply system.

The degassing device includes, for example, a device for lowering the pressure of the curtain coating auxiliary liquid in the supply system through a degassing membrane and a device for raising the temperature of the curtain coating auxiliary liquid. Can be used from those described below. As a dissolved oxygen analyzer, Toa Denpa Kogyo Co., Ltd.
Portable dissolved oxygen meter.

There are sterilizing apparatuses using heat, ultraviolet rays, chemicals, etc., but any apparatus having a sterilizing effect may be used. As a sterilizer, there is, for example, Ministereria, an ultraviolet water flow type sterilizer manufactured by Funakoshi Co., Ltd. The effect of these sterilizers is great when using an auxiliary liquid, such as pure water or an aqueous gelatin solution, in which bacteria are likely to be generated.

The temperature and pressure in the system are changed for degassing, but the pressure is low at the auxiliary liquid supply port.
Bubbles often occur. For this reason, the auxiliary liquid is made to be finally unsaturated in the auxiliary liquid supply port.

[0027]

Embodiments of the present invention will be described below with reference to the drawings, but the present invention is not limited thereto.
In the following description, although there are definite expressions for terms and the like, they show preferred examples of the present invention, and do not limit the meaning of the terms of the present invention and the technical scope.

First, a specific example of curtain coating to which the present invention is applied will be described. In the following examples, a case where a negative film is produced by mainly applying an emulsion for a photographic light-sensitive material on a photographic film support will be described, but the present invention is not limited to this example. When curtain coating is performed on the conveyed support, it can be applied to the manufacture of magnetic recording materials such as photographic printing paper and magnetic tape, and information recording paper such as pressure-sensitive paper and heat-sensitive paper.

FIG. 1 shows a curtain coating apparatus 1 according to the present invention, which applies curtain coating to a support B in the process of being reversed by a backup roller R in the transport direction. Further, since the coating is performed in the process of reversing the transport direction by the backup roller R, the coating liquid does not splash and contaminate the support on the upstream side in the transport direction.

The support B is transported by transport means (not shown). As the support to be transported, paper, coated paper, plastic film, resin film, thin metal plate, or the like is used, and can be appropriately selected in order to obtain an object to be coated.
Further, the backup roller R may or may not contact the support. In the case of a backup roller that does not contact the support, a so-called air back roll that blows fluid such as air from a number of small holes provided on the roller surface can be used.

The curtain coating apparatus 1 includes at least a slide surface 2, a coating liquid supply slit 3, an edge guide 4,
4 ', side plates 5 and 5'.

The coating liquid is supplied uniformly in the width direction from the coating liquid supply slit and flows down the slide surface,
A thin film of the coating liquid is formed. The thin film flows down the slide surface, propagates in a curtain film shape between a pair of edge guides 4 and 4 ′ provided at both ends of the lower end portion of the slide surface, flows down, and collides with the transported support B. A coating layer is formed.

Also, a predetermined number of slits for uniformly supplying the coating liquid can be provided as necessary. By flowing the coating liquid from a plurality of slits, a thin coating liquid can be laminated. FIG. 1 shows a side view of a slide surface provided with three slits.

FIG. 2 is a perspective view of the slide surface 2. Side plates 5 and 5 'are provided at both ends of the slide surface 2 of the coating device 1, and regulate the coating liquid supplied from the slit 3 so as not to flow down from the slide surface side end. ing. The side plates 5, 5 'are provided with a liquid inlet 6, which is a supply outlet for the auxiliary liquid. The shape of the liquid inlet 6 is rectangular, and one side thereof is in contact with the slide surface. As shown in FIG. 3, the injection port 6 is connected to an injection mechanism, that is, a curtain coating auxiliary liquid supply system 30, and supplies an auxiliary liquid (side liquid) such as a gelatin solution, water, or an organic solvent. By supplying the auxiliary liquid from the injection port 6, the coating liquid flowing down on the slide surface 2 flows down along with the auxiliary liquid at the boundary between the side plates 5 and 5 ', and passes through the auxiliary liquid as it is. And propagates between the edge guides and is applied to the support. Further, an equal amount of the auxiliary liquid is caused to flow down from each of the liquid injection means on both sides. The amount of the auxiliary liquid may be any amount, but is generally supplied at about 0.3 to 50 cc / min. Thus, the curtain film can be formed stably, and the film thickness unevenness near the edge guide can be reduced.

Further, the injection port 6 on which the side liquid works effectively.
Can be appropriately designed and adjusted in consideration of the height of the coating solution flowing down the slide surface 2.

Since the purpose of the auxiliary liquid is to minimize the boundary layer of the falling liquid film formed near the edge guide, it is sufficient that the liquid injection port 6 is provided on both sides on the slide surface. That is, it may be on either side between the lip and the uppermost supply slit.

Next, the supply system 30 of the curtain coating auxiliary liquid will be described with reference to the configuration diagram of FIG. However, this system is an example, and the order of each unit is not limited to that shown here. Between the pot 31 containing distilled water as a curtain coating auxiliary liquid and the injection port 6 of the coating apparatus 1,
A sterilizer 41, a filter 42, a deaerator 51, a flow meter 61, and a flat valve 62 are connected by a liquid feed pipe 32 or the like, and a small flow rate of 0.3 to 3 cc / min of distilled water is uniformly supplied to the inlet 6. Supplied to In this system, there is no liquid feed pump, but the head difference from the pot 31 to the liquid inlet 6 is supplied as a driving force. Of course, the pressure may be applied to the kettle or supplied using a liquid sending pump.

As the disinfecting device 41, an ultraviolet water disinfecting device manufactured by Funakoshi Co., Ltd., a germicidal lamp such as Ministerellia (trade name) is simple and has a considerable effect. In this case, tube 3
2 is convenient because a transparent pipe can be used and ultraviolet rays can be irradiated from the outside.

As the deaerator 51, a gas torch (trade name), which is an ultra-compact high-performance solvent deaerator made by LaboCotech Co., Ltd., or a degasser (trade name), which is an aqueous deaerator made by ERC Co., Ltd., is used.

The dissolved gas means the concentration of all the gases dissolved in the liquid. Usually, in the atmosphere, the composition of the gas is constant. . That is, the dissolved air can be completely specified by measuring the dissolved oxygen, and the measurement of the dissolved oxygen makes it possible to determine the unsaturation of the air.

As the dissolved oxygen measuring device 71, a portable dissolved oxygen meter manufactured by Toa Denpa Kogyo KK or the like is used.

As the flow meter 61, a thermal mass flow meter for liquids and a controller therefor are preferred. Specifically, a mass flow controller LV series manufactured by S-Tech Co., Ltd. and a trade name of Mass Flow Controller LV or Oval Co., Ltd. Brand name MA
SFLO-OVAL, LIQUI-FLOW (MODE
LF-900L series) and Brooks FLOME (trade name, manufactured by Fisher Rosemount Japan)
GA ^TM (Flow Mega) and Lintec Corporation LC
A -1100M liquid mass flow controller or the like is suitable.

The flow rate feedback control by the flow meter 61 such as the thermal mass flow meter and the controller such as the flat valve 62 has provided the basic flow rate stability for a considerable period of time, but it is still satisfactory. It was not. This has been found to be due to the following reasons.

Here, the liquid used for the auxiliary liquid is usually at the same liquid temperature as room temperature, and is 15 to 20 ° C. In a production process by curtain coating (for example, a photosensitive material), the temperature is often higher than this temperature, and the dissolved air as a dissolved gas is saturated, so that the dissolved gas cannot be completely dissolved and grows as bubbles. The growth of the bubbles interrupts the supply of the auxiliary liquid having a very small flow rate or causes the flow rate to fluctuate, so that the thick film phenomenon at both ends in the width direction cannot be eliminated and the film thickness is disturbed. In order to avoid this, in the auxiliary liquid supply system, degassing was performed by the above-described degassing device, and the dissolved gas was reduced to a saturation amount or less, so that generation of bubbles could be eliminated. The thick film phenomenon at both ends in the width direction is eliminated, and uniform coating can be stably maintained for a long period of time. This is particularly effective when the flow rate of the auxiliary liquid is low.

[0045] In addition, due to the generation of bacteria, film-like dirt is formed in the piping, and this is the measurement part of a precise flow meter,
The cause of the failure of the flat valve 62, which is the flow control valve, has been almost completely eliminated by providing the sterilizing device 41 described above.

Further, by providing the filter 42 between the sterilizer 41 and the flow meter 61, it is possible to capture bacteria, water scum, etc. killed by the sterilizer 41. Thus, the film can operate more stably, and the film thickness in the width direction can be stabilized for a longer time. The filter 42 may be installed immediately after the sterilizer 41 or immediately before the flow meter 61 in the auxiliary liquid supply direction.

Further, while monitoring the measured value of the dissolved oxygen measuring device 71, it can be confirmed that there is no danger of bubble generation. When the amount of dissolved oxygen is increased by the feedback device 72 based on this value, the output of the deaerator 51 can be increased.

The auxiliary liquid supply system may be one obtained by removing only the sterilizing device 41 from the auxiliary liquid supply system 30 shown in FIG. 3, or may be obtained by removing only the deaerator 51. However, it is more effective to provide both devices 41 and 51 together.

The auxiliary liquid supply system 30 comprises a section from the pot 31 in which the liquid having the liquid composition to be supplied is formed to the liquid inlet 6 which is an auxiliary liquid outlet.

[0050]

EXAMPLE 1 The auxiliary liquid supply system 30 described in the above embodiment uses distilled water at 20 ° C. (saturated dissolved oxygen amount: 8.8 ppm) as the auxiliary liquid, and the injection of the auxiliary liquid at the supply outlet. The amount of dissolved oxygen in the mouth 6 and the flow rate of the auxiliary liquid were changed to examine the state of generation of bubbles. The total length of the auxiliary liquid supply system at this time was about 5 m, the inner diameter of the pipe 32 was 5 mm, and a gelatin-containing liquid for a photosensitive material was applied by a curtain coating method.

Table 1 shows the results.

[0052]

[Table 1]

Evaluation criteria ○: No bubbles were generated by continuous supply for 48 hours. Δ: No bubbles were generated by continuous supply for 12 hours, but were generated within 48 hours. X: Bubble was generated within 12 hours. Good and intentionally mixed air bubbles also tend to disappear (△ and × impede stable production). Thus, the generation of air bubbles can be eliminated by reducing the amount of dissolved gas to the saturation level or less. In addition, when the auxiliary liquid is used under a low flow rate, the problem is large when bubbles are generated, and thus it can be seen that the effect of adopting the present invention is large.

Example 2 Using the same auxiliary liquid supply system 30 as in Example 1, distilled water at 20 ° C. (saturated dissolved oxygen amount 8.8) was used as the same auxiliary liquid.
ppm), the generation of water scum in the pipes with and without the sterilizer 41 was examined. Table 2 shows the results.

[0055]

[Table 2]

Evaluation Criteria ： １: No water deposits were generated even after one month of use. Δ: No water deposits were generated even after 10 days of use, but occurred within 1 month. ×: Water deposits were generated within 10 days. It can be seen that the effect of the sterilizer is great.

[0057]

According to the auxiliary liquid supply method of the present invention, it is possible to reduce the dissolved gas to a saturated amount or less to eliminate the generation of bubbles,
Further, by attaching the sterilizing device, it is possible to prevent film-like stains adhering to the inside of the pipe. As a result, thick film coating at the end in the width direction in curtain coating is eliminated, and uniform high quality and high productivity curtain coating can be stably obtained for a long period of time.

In particular, in the production under the condition that the flow rate of the auxiliary liquid is low, the problem becomes more serious when bubbles are generated, so that the effect of employing this technique is great.

[Brief description of the drawings]

FIG. 1 is a side view of a coating apparatus according to the present invention.

FIG. 2 is a perspective view of a coating apparatus according to the present invention.

FIG. 3 is a configuration diagram of an auxiliary liquid supply system according to the present invention.

FIG. 4 is a view showing non-uniform film thickness at the edge of a support during curtain coating.

[Explanation of symbols]

 Reference Signs List 1 coating device 2 slide surface 3 coating liquid supply slit 4, 4 'edge guide 5, 5' side plate 6 filling port 30 auxiliary liquid supply system 31 kettle 32 tube 41 sterilizer 42 filter 51 deaerator 61 flow meter 62 flat Valve 71 Dissolved oxygen measuring device 72 Feedback device

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Tetsuya Shiraishi 28 Konica Corporation, Horinouchi, Odawara City, Kanagawa Prefecture (72) Inventor Teruyuki Higashi 28 Konica Corporation, Horinouchi, Odawara City, Kanagawa Prefecture (72) Inventor Ei Shibata YA 28 Korinouchi, Odawara-shi, Kanagawa Prefecture Konica Corporation F term (reference) 4D075 AC15 AC86 AC88 AC92 AC99 CA45 CA48 DA04 EA05 4F041 AA12 BA07 BA12 BA34 BA57 CA04 CA25

Claims (13)

[Claims] 1. A coating liquid is supplied from a coating liquid supply slit of a coating device to a slide surface, and an auxiliary liquid is discharged from liquid injection ports of side plates provided on both sides of the slide surface. A curtain film is formed by an edge guide from the lip of the lip, and the curtain film is applied to the conveyed support by colliding the curtain film with the auxiliary liquid. A method for supplying a curtain coating auxiliary liquid, wherein an amount of dissolved gas of the auxiliary liquid at a supply outlet of the auxiliary liquid is set to an unsaturated state. 2. A coating liquid is caused to flow out of a coating liquid supply slit of a coating apparatus onto a slide surface, and an auxiliary liquid is caused to flow out from liquid injection holes of side plates provided on both sides of the slide surface, and the slide surface final end is provided. A curtain film is formed by an edge guide from a lip of the above, and the curtain film is colliding with a conveyed support to apply the curtain film. A method for supplying an auxiliary liquid for curtain application, wherein a sterilizing device is provided in the inside to sterilize the auxiliary liquid in the system. 3. An application liquid is caused to flow out of a coating liquid supply slit of a coating apparatus onto a slide surface, and an auxiliary liquid is caused to flow out from a liquid inlet of a side plate provided on both sides of the slide surface, and the slide surface final end. A curtain film is formed by an edge guide from the lip of the lip, and the curtain film is applied to the conveyed support by colliding the curtain film with the auxiliary liquid. Dissolving the amount of dissolved gas in the auxiliary liquid at a supply outlet of the auxiliary liquid into an unsaturated state, and disposing a sterilizer in the curtain coating auxiliary liquid supply system to sterilize the auxiliary liquid in the system. Curtain coating auxiliary liquid supply method. 4. A coating liquid is supplied from a coating liquid supply slit of a coating device to a slide surface, and an auxiliary liquid is discharged from liquid inlets of side plates provided on both sides of the slide surface, and the slide surface final end. A curtain film is formed by an edge guide from a lip of the above, and the curtain film is colliding with a conveyed support to apply the curtain film. A method for supplying a curtain coating auxiliary liquid, wherein the auxiliary liquid is continuously degassed and / or sterilized until the outlet. 5. A flow rate of said auxiliary liquid is 0.3 to 3 on one side.
The method for supplying a curtain coating auxiliary liquid according to any one of claims 1 to 4, wherein the supply rate is cc / min. 6. The method according to claim 5, wherein the flow rate of the auxiliary liquid is measured by a thermal mass flow meter. 7. The method according to claim 5, wherein the flow rate of the auxiliary liquid is controlled using a flat valve. 8. The curtain coating auxiliary liquid supply method according to claim 1, wherein a deaerator is provided in the curtain coating auxiliary liquid supply system to perform degassing. 9. The curtain coating auxiliary liquid supply method according to claim 8, wherein feedback is applied to the deaerator while monitoring the dissolved oxygen amount of the auxiliary liquid. 10. The method according to claim 2, wherein a filter is provided between the sterilizer and the flow meter for sterilization. 11. The method according to claim 10, wherein the filter is located immediately after the sterilizer. 12. The method according to claim 10, wherein a filter other than the filter is provided immediately before the flow meter. 13. The curtain coating auxiliary liquid supply method according to claim 1, wherein the coating liquid is a coating liquid containing gelatin.