JP2003159555A - Method for manufacturing simultaneous multilayer slide-type coater and recording material - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method that, when an organic solvent coating solution mainly consisting of a solvent of a lower boiling point of water is applied with a simultaneous multilayer slide-type coater, the generation of a defect in coating is eliminated, a coating performance and safety are highly improved, or the vaporization of a solvent from a slide-face is prevented, a deformation caused by a change in temperature of a coater dice is reduced and a change in film thickness distribution in time/width direction is lessened. <P>SOLUTION: The simultaneous multilayer slide-type coater comprises two slits or more separately extruding the coating solution, and the slits comprises three bars or more. A coating is simultaneously applied to two coated layers or more. A cover covers a sliding face, a side face, and a rear face. A means for supplying an inert gas moistened in a scope of relative humidity of 50 to 100% by a solvent of the largest weight contained in the coating solution is provided so as to allow the concentration of oxygen in the cover to be 8% or less. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a slide coater for simultaneous multi-layer coating of coating liquids, and more particularly to simultaneous multi-layer coating of an organic solvent-based coating liquid whose main component is a solvent having a boiling point lower than that of water. The present invention relates to a multi-layer slide coater and a recording material manufacturing method using the same.

[0002]

2. Description of the Related Art Generally, a slide coater for simultaneous multi-layer (hereinafter also referred to as a coater) is widely used in a coating device for a photosensitive material, a magnetic recording material, etc., because high-speed, thin-film and multi-layer simultaneous coating is possible. Has been. This type of coater
It is known that a coating liquid extruded from a slit between bars forming a coater flows down a slide surface which is an upper surface of the coater and is applied to a running belt-shaped support.

Generally, when coating is performed using a coater,
The coating is carried out under control so that the slits do not become clogged with foreign matter, the coating failure due to the adhesion of bubbles, and the coating failure due to the evaporation of the coating liquid on the slide surface do not occur. For clogging of foreign matter into the slit and adhesion of air bubbles, the coating liquid that has passed through the filter is used, but when used for a long time, air bubbles, precipitates, etc. generated in the coating liquid supply path to the coater,
Foreign matter or the like often adheres to the slit or is clogged. If any of these occur, a coating streak failure will occur immediately.Therefore, the operator observes the state of the coating solution flowing on the slide surface of the coater, and if any foreign matter adheres to the slit or clogging is found, remove it immediately and correct the coating failure. Application is performed while minimizing the amount.

Further, the coater has a drawback that the coating liquid flowing on the slide surface has a free interface, so that it is very susceptible to the influence of wind. Particularly in the case of an organic solvent-based coating liquid whose main component is a solvent having a boiling point lower than that of water, the evaporation of the solvent from the slide surface is promoted by the wind. Especially when the coating speed is slow, the solid content concentration rises due to evaporation in the uppermost layer on the slide surface, causing small orange pail-shaped coating unevenness, streak failure and even pitch-like unevenness in the width direction on the coating surface. As a result, the coating property was deteriorated. If these coating failures occur, the product does not become a product and the operation rate of the process is extremely low.

The simplest method of eliminating the influence of wind is to keep the area around the coater free of wind. However, when handling an organic solvent-based coating solution, the operator's health care and explosion-proof management of the coating apparatus are controlled. Due to the above problem, it is common to take the necessary minimum amount of air around the coater.

By suppressing the evaporation of the coating liquid on the slide surface and keeping the gas concentration on the slide surface high, it is possible to suppress the occurrence of orange pail-shaped coating unevenness failure and streak failure due to evaporation. Various studies have been made to suppress the evaporation of the coating liquid.

[0007] For example, Japanese Patent Laid-Open No. 55-75758 discloses a technique of attaching a hood above the slide surface of an organic solvent coating apparatus, but since the hood is quite large, the gas concentration on the slide surface is low. This is not a sufficient measure because it promotes evaporation and promotes evaporation. Japanese Examination 6-2
No. 7929, in order to prevent the occurrence of air convection caused by the temperature difference between the temperature of the coating liquid and the air in contact with the coating liquid,
A technique is disclosed in which a slide cover called shield means is provided as close to the slide surface as possible, and the shield means is kept at the same temperature as the coating liquid temperature. However, since the shield means is constantly heated to the temperature of the coating liquid, a considerable amount of energy is used, which leads to an increase in cost.

Japanese Unexamined Patent Publication No. 9-225380 discloses a technique in which a cover having a structure provided with a wind shield for preventing evaporation from the slide surface is provided close to the slide surface. However, since the structure is complicated and the state of the coating liquid flowing on the slide surface cannot be seen, the detection of foreign matter adhesion to the slits and clogging of foreign matter is delayed, and as a result, coating that does not become a product is performed. There is much waste of coating liquid, resulting in higher costs.

In such a situation, when a coater is used to apply an organic solvent-based coating liquid whose main component is a solvent having a lower boiling point than water, which requires sufficient ventilation, evaporation from the slide surface is suppressed. In order to meet the demand for a simple and inexpensive coating apparatus that secures a uniform coating surface and does not reduce productivity, the inventors of the present invention have disclosed in Japanese Patent Application No. 2000-138196 a means for cooling a slide surface and a slide. We have proposed a slide type coater for simultaneous multi-layering, which has a cover that covers the surface, side surface, and rear surface.

[0010]

However, it has been found that the above coater is in a state of containing a large amount of solvent vapor inside the installed cover, which causes a safety problem.
In particular, when an organic solvent having a boiling point of 40 to 85 ° C. is used, the tendency is remarkable, and the lower explosion limit may be exceeded as the solvent concentration inside the cover increases.

Further, the temperature of the slide surface decreases due to latent heat of vaporization due to the non-uniform evaporation of the solvent on the slide surface. Therefore, it became clear that the temperature change on the slide surface became large, the coater die was deformed by the temperature change, and the film thickness distribution across the width changed with time.

Further, when the temperature of the inner surface of the cover (the side facing the slide surface) is lower than the temperature of the atmosphere covered by the cover and the slide surface, dew condensation occurs on the inner surface of the cover and drops of the condensed solvent. Also dropped onto the slide surface, causing a problem of coating failure.

The present invention has been made in view of the above circumstances, and a first object of the present invention is to apply an organic solvent-based coating liquid containing a solvent having a boiling point lower than that of water as a main component by means of a simultaneous multi-layer slide coater. In doing so, the coating failure represented by orange pail is eliminated as much as possible, and a coater having not only high basic coating performance but also improved safety is provided.

A second object is to prevent nonuniform solvent evaporation from the slide surface, thereby minimizing deformation of the coater die due to temperature change and reducing change in film thickness distribution in the lateral direction with time. .

A third object is to prevent dew condensation on the surface of the cover which covers the slide surface, which is caused by the evaporated solvent, and to prevent coating failure due to the drop of the condensed solvent dripping on the slide surface. .

A fourth object is to provide a method for producing a recording material by applying a coating liquid using the above coater.

[0017]

The above-mentioned problems of the present invention can be solved by the following constitutions.

1. The opposite surface of the coating is held by a back roll, and the boiling point is 40 to 85 ° C. to the belt-shaped support that is continuously conveyed.
It is composed of two or more slits for separately extruding the coating liquid containing the polymer resin into the solvent containing the organic solvent, and three or more bars forming the slits, and simultaneously coating two or more coating layers. In the simultaneous multilayer slide coater, the cover is formed on the coater to cover the slide surface, the side surface and the rear surface, and the oxygen content in the cover is 8% or less. A simultaneous multi-layer slide coater, characterized in that means for supplying an inert gas moistened to a relative humidity of 50 to 100% by a large amount of solvent is provided.

2. An inert gas supply port is provided above a slit on the slide surface for discharging the coating liquid forming the uppermost layer of the coating film, and is connected to a portion of the cover which covers the rear surface of the slide surface. And 1
The slide coater for simultaneous multilayering described.

3. 2. The simultaneous multi-layer slide coater according to claim 1, wherein the means for supplying the inert gas is provided so as to be connectable to a portion of the cover that covers the side surface of the slide surface.

4. The opposite surface of the coating is held by a back roll, and the boiling point is 40 to 85 ° C. to the belt-shaped support that is continuously conveyed.
It is composed of two or more slits for separately extruding the coating liquid containing the polymer resin into the solvent containing the organic solvent, and three or more bars forming the slits, and simultaneously coating two or more coating layers. In the simultaneous multi-layer slide coater, a cover is formed on the coater to cover the slide surface, the side surface and the rear surface, and the temperature of the inner surface of the cover facing the slide surface is the ambient temperature covered by the slide surface and the cover. A slide type coater for simultaneous multi-layering, characterized by being maintained at a higher level.

5. 5. The simultaneous multi-layer slide coater according to any one of 1 to 4, wherein the coating liquid is an organic solvent-based coating liquid whose main component is a solvent having a boiling point lower than that of water.

6. 6. The simultaneous multi-layer slide coater according to any one of 1 to 5, wherein the cover is detachably provided.

A method for producing a recording material, which comprises applying the coating liquid using the slide coater for simultaneous multilayering according to any one of 7.1 to 6 to produce a recording material.

8. 8. The method for producing a recording material as described in 7, wherein the recording material is a heat developable silver salt medium.

The present invention will be described in detail below. The simultaneous multi-layer slide coater of the present invention is provided with a cover that covers the slide surface, the side surface, and the rear surface, so that the oxygen concentration in the cover is 8% or less. According to the present invention, there is provided a means for supplying "inert gas moistened to a relative humidity of 50 to 100%". The term “simultaneous multi-layer” means not only two layers but multi-layer coating of multiple layers at the same time.

In the present invention, the relative humidity is expressed as follows. ψ = (P / Ps) × 100 ψ: Relational humidity P: Vapor pressure Ps: Saturation vapor pressure Related humidity is Robert H. Perry / Ceci
lH. Childon, “Chemical Eng”
iners' Handbook ", 5thed.,
As described in McGraw-Hill, P20-7, it is possible to obtain it from a humidity chart of organic vapor showing various characteristics of a mixed gas of organic vapor-gas and gas.

The saturated vapor pressure at any temperature is
R. It can be estimated by the Antoine vapor pressure formula described in “Physical Property Estimation Handbook”, 3rd edition, P185 by C-Reed et al., Translated by Mitsuho Hirata, McGraw-Hill Book Co., Ltd.

On the other hand, the vapor pressure is Dal described in Yasushi Eguchi, Kagaku Dojin Co., Ltd., “Chemical engineering stoichiometry” P82.
The vapor pressure can be estimated from Ton's law and P83's Magat's law from the volume ratio (Vol%) of the solvent gas in the atmosphere measured by a gas chromatograph.

As a method of moistening the inert gas with a solvent having the highest mass contained in the coating liquid, for example, organic vapor, a method of passing the inert gas through a closed container filled with the organic solvent is simple and preferable.

Examples of the inert gas include nitrogen, argon, helium, carbon dioxide gas, etc., but nitrogen is preferable in terms of cost. As a supply method, a method of supplying from a high-pressure gas cylinder, a method of supplying from a liquefied gas storage tank through a liquefied gas evaporator, and PSA (Pressure Swing A)
It is possible to use a method of supplying by using an air separation device of dsorption (pressure fluctuation adsorption) type, a method of supplying by using a membrane separation method, or the like. Of these, the membrane separation method is most preferable in the present invention because of its low operating cost.

In the case of using a coating liquid containing a polymer resin in a solvent containing an organic solvent having a boiling point of 40 to 85 ° C.,
It is unavoidable to dry on the slide surface while the coating solution is flowing.

Therefore, by installing a solvent evaporation preventing cover on the slide surface, it is possible to reduce the evaporation of the solvent, and to prevent a coating failure on the slide surface caused by the drying of the coating solution containing the polymer resin in the solvent containing the solvent. It is possible to reduce the occurrence.

Further, when an inert gas containing a large amount of solvent vapor is supplied to the inside of the cover to bring it into a state containing a large amount of solvent vapor, evaporation of the solvent from the slide surface is reduced and at the same time,
Since the solvent vapor can be suppressed to the lower limit of explosion, it is possible to improve safety.

That is, the above organic solvent exceeded the lower limit of explosion when the solvent concentration became higher in the atmosphere and was insufficient in terms of safety, but by supplying the above inert gas to fill the inside of the cover, It is possible to safely fill the slide surface with solvent vapor.

The above-mentioned inert gas is further upstream, for example, in the widthwise coating direction, from a slit on the slide surface which discharges the coating liquid forming the uppermost layer of the coating film (uppermost gas-liquid solid interface of the slide surface). By supplying the air while rectifying the air through the slit-shaped notches, it is possible to prevent fluffing due to the effect of the air blown on the slide surface. The gas-liquid solid interface refers to the boundary between the upstream side of the coating liquid ejection portion of the slit for extruding the coating liquid and the surface side of the coating liquid extruded from the slit. When the solvent concentration in this portion is lowered, the coating liquid is solidified along the width direction of the boundary portion, impairing the surface property on the slide surface, which leads to deterioration of the coating property.

As another aspect of the simultaneous multilayer slide coater of the present invention, a cover for covering the slide surface, the side surface and the rear surface is formed, and the surface temperature of the cover facing the slide surface is controlled by the slide surface and the cover. It is characterized in that the temperature is kept higher than the covered ambient temperature.

When the temperature of the inner surface of the cover, that is, the surface facing the slide surface and in contact with the solvent vapor atmosphere is lower than the ambient temperature covered by the slide surface and the cover, dew condensation of the solvent vapor occurs on the inner surface of the cover, It will become drops and drop on the slide surface, causing coating failure. Therefore, if the temperature of the inner surface of the cover is maintained higher than that of the solvent vapor atmosphere, specifically, at least 0.2 ° C. or higher, coating failure due to dew condensation is eliminated and coating property is also improved.

Next, the operation of the present invention will be described. (1) In the case of application of a working solvent system (particularly, an organic solvent having a boiling point of 40 to 85 ° C.) in which the inside of the cover is enhanced with an inert gas together with a solvent vapor, the surroundings of the slide type coater are a solvent atmosphere, Air replacement is frequently performed. Further, in solvent-based coating, the latent heat of vaporization of the solvent used is about 1/3 of that of water.

Therefore, on the slide surface of the slide type coater, a windproof cover that can be installed and removed instantly is installed, and the inside of the cover is made into a solvent vapor atmosphere containing a large amount of solvent vapor, and then the feeding of the coating liquid is started. Alternatively, if the coating liquid is fed, the evaporation of the solvent on the slide surface is significantly suppressed at the beginning of the liquid feeding and at the time of the liquid feeding. At that time, if the concentration of the solvent in the cover increases, the organic solvent exceeds the lower limit of explosion, and there is concern about safety. Therefore, by supplying inert gas together with solvent vapor to set the oxygen concentration in the cover to 8% or less, it becomes possible to fill the slide surface with a mixed gas of solvent vapor and inert gas. , Improvement of safety is expected.

In order to set the oxygen concentration in the cover to 8% or less by supplying the inert gas together with the solvent vapor, in the cover for covering the slide surface, the side surface and the rear surface of the slide coater,
This can be achieved by supplying "an inert gas moistened with a relative humidity of 50 to 100% by the solvent having the highest mass contained in the coating liquid" so that the oxygen concentration is 8% or less.

Even when the inside of the cover is filled with an inert gas, the evaporation of the solvent from the slide surface can be effectively suppressed by increasing only the evaporation concentration of the solvent on the slide surface. It is possible to prevent the thermal deformation of the slide coater caused by the heat balance due to the latent heat of vaporization on the slide surface from the start of the liquid.

After the liquid feed is started, the surface of the coating liquid on the slide surface receives heat from the surroundings, and the evaporation latent heat is removed by the solvent evaporation on the surface. As a result, the surface temperature of the coating liquid becomes a dynamic equilibrium temperature at which the two are balanced. This dynamic equilibrium temperature is generally lower than the ambient temperature as the amount of evaporation increases. The slide surface temperature also decreases due to the heat transfer due to the decrease in the coating liquid surface temperature. When the slide surface temperature decreases, the material of the coater die is generally stainless steel (SUS304, SUS31).
6, SUS630 (manufactured by Hitachi Metals, Ltd.), etc., so that the member is thermally deformed due to member contraction due to temperature change. Therefore, by suppressing the evaporation of the solvent, it is possible to reduce the decrease in the coating liquid surface temperature, and as a result, it is possible to suppress the thermal deformation of the slide coater surface due to the temperature change.

In the present invention, it is preferable to make the height of the cover and the sliding surface narrower and narrower than the boundary layer. As a result, when the inert gas is supplied, the inside of the cover is immediately saturated with the solvent vapor, and evaporation from the slide surface inside the cover is easily suppressed. (2) Action of forming the slit by supplying the above-mentioned inert gas The means for supplying the above-mentioned inert gas is provided with a slit on the slide surface for discharging the coating liquid forming the uppermost layer of the coating film (the uppermost stream of the slide surface). It is preferably arranged further upstream than the gas-liquid solid interface). As a supply form, for example, a rear part of a cover that covers the slide surface is formed with a slit-like notch (hereinafter referred to as a slit) in the width application direction, and when the inert gas is rectified and supplied from the slit, the slide surface is formed. Since everything can be effectively and uniformly made into an atmosphere containing solvent vapor, and the air blown onto the slide surface can be rectified, it is possible to prevent inadvertent disturbance on the slide surface. Further, as a supply form, in addition to the slit, it is also possible to cover an inert gas blowout part at the rear part of the cover that covers the slide surface with a punch plate, a mesh plate, or the like,
Further, if there is no disturbance on the slide surface, it may be supplied by a circular pipe or a square duct. (3) Action by suppressing the surface temperature inside the cover When the surface temperature inside the cover facing the slide surface is lower than the ambient temperature covered by the slide surface and the cover, dew condensation of solvent vapor occurs on the surface inside the cover, and the slide occurs. The drops will drop on the surface, causing coating failure. Therefore, it is necessary to maintain the temperature of the surface inside the cover, which is in contact with the solvent atmosphere between the slide surface and the cover, high. By making the temperature higher than the solvent atmosphere by at least 0.2 ° C. or more, dew condensation can be prevented, and coating with good coating properties can be performed without coating failure due to the drop of dew condensation. Examples of means for maintaining a high surface temperature inside the cover include a method of using a medium such as steam and hot water and providing a pipe with a circulation circuit for the medium, and heating with an electric heater.

As yet another method, a material having a thin cover and good thermal conductivity is used so that the cover temperature is substantially the same as the ambient temperature outside the cover, and the wetness is lower than the ambient temperature outside the cover. It is possible to supply an active gas to the inner surface of the cover and set the surface temperature of the inner surface of the cover higher than the environmental temperature inside the cover. In consideration of safety, the material of the cover is nonflammable and conductive, and the thickness is preferably 1 mm or less, more preferably 0.5 mm or less. For example, an aluminum plate having a thickness of 150 to 300 μm is preferable because it has good thermal conductivity, is thin, and is inexpensive.

According to the present invention, as described above in (1), drying of the solvent on the slide surface is significantly suppressed, and conventionally, a solvent system containing a solvent as a main component having a lower boiling point than water is applied. When the slide type simultaneous multi-layer coating is performed, partial coating film generation (for example, solidification of the coating liquid at the most upstream gas-liquid solid interface on the slide surface) and streaks caused by evaporation of the main solvent There is no coating failure represented by the orange pail, and a recording material with excellent quality and productivity can be obtained safely.

Further, the heat balance for the slide type coater due to the latent heat of vaporization of the solvent evaporated on the slide surface can be greatly reduced, and as a result, the coater die is deformed due to the temperature change or the coating film thickness due to thermal deformation. It is possible to obtain a recording material that prevents the distribution from changing and is excellent in quality and productivity.

In (2), by rectifying air supply to the slide surface, partial convection is prevented and the homogenization of the solvent atmosphere on the slide surface is further promoted. That is, it is possible to obtain a recording material having excellent quality and productivity by preventing the disturbance of the evaporated solvent and the supplied inert gas on the slide surface.

In (3), it is possible to obtain a recording material which is excellent in quality and productivity by preventing the evaporation solvent from being condensed on the inner surface of the cover.

[0050]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described with reference to the drawings, but the present invention is not limited thereto.

FIG. 1 is a schematic view showing an example of a coating state using a coater provided with means for supplying an inert gas. In the figure, 1 indicates a coater, which is a coater capable of simultaneous coating of three layers. The material of the die is generally stainless steel (SU
S304, SUS316, SUS630 (manufactured by Hitachi Metals, Ltd.) and the like. 101a, 101b, 101
Reference numerals c and 101d indicate bars that form the coater. The coater determines the number of layers applied by the number of combinations of these bars. Although this figure shows a coater for simultaneous three-layer coating, it is of course an example and is not limited to this. 102a indicates a slit formed between the bars 101a and 101b, 102b indicates a slit formed between the bars 101b and 101c, and 102c indicates a slit formed between the bars 101c and 101d.
103a, 103b, 103c are supply pipes 303a, 3
3B shows a liquid pool for uniformly extruding the coating liquids sent from 03b and 303c through the slits 102a, 102b and 102c in the width direction. Reference numeral 2 denotes a cover put on the coater 1. The cover 2 can be attached / detached by an attaching / detaching device not shown in the figure. 3 shows a coating liquid supply system, 301a, 301b and 301c show coating liquid preparation tanks, 302a, 302b and 302c show pumps for liquid feeding, and 303a, 303b and 303c.
Indicates a supply pipe for supplying each coating liquid to the liquid reservoir formed between each bar. Reference numeral 4 represents an inert gas supply system containing solvent vapor, 401 represents a closed container containing an organic solvent (for example, methyl ethyl ketone), 402 represents a pressure gauge for inert gas, and 403 represents a pressure control valve. By adjusting the pressure adjusting valve 403, the amount of inert gas supplied to the inside of the cover can be adjusted. This inert gas flow rate is a method of controlling the gas flow rate itself,
There is a method of measuring the pressure inside the cover and controlling the flow rate.
Here, the pressure inside the cover is 0.1 to 10 Pa, preferably 0.1 to 5 P, although it depends on the volume in the cover and the distance between the slide surface and the downstream side, that is, the gap between the cover tip and the support.
It is preferable to adjust the supply amount of the inert gas so that the internal pressure is higher than that outside the cover within the range of a. Also, 404
Indicates a supply pipe for supplying the inert gas containing the solvent vapor to the inside of the cover 2, that is, the slide surface and the region covered by the cover 2. As the inert gas, for example, nitrogen gas is used. Reference numeral 5 denotes a back roll, 6 denotes a belt-shaped support having an opposite surface coated with the back roll, which is continuously conveyed in the arrow direction, and 7 denotes a coating layer applied to the belt-shaped support. Reference numeral 8 denotes a decompression chamber, 801 denotes a wall of the decompression chamber, and 802 denotes a suction pipe. W represents a coating point at which the coating liquid is coated on the belt-shaped support 6 by the coater 1, and is preferably located 10 to 20 degrees above the horizontal axis passing through the center of the back roll.

FIG. 2 is a schematic enlarged view of the cover 2 attached to the coater 1 and having a partially broken surface. 104 in the figure
Indicates a coating width regulating plate disposed at both ends of the upper surface of the slide coater. 105a, 105b, 105c, 10
5d is each bar 101a, 101b, 101c, 101d
The slide surface which is the upper surface of FIG. The coating solution extruded from each slit flows down in a state of being laminated on these slide surfaces, and is applied to a belt-shaped support supported by a back roll. The angle of the sliding surface when applying is preferably 10 to 60 degrees. The angle of the sliding surface means the angle at which the horizontal axis passing through the center of the back roll intersects with the extension line of the sliding surface. Reference numerals 201a, 201b, 201c, and 201d denote engaging members for attaching and detaching the cover 2 when the cover 2 is attached and detached. The member may be disposed on the side surface. If the cover is small, it can also be used as a handle. 202a, 20
Reference numeral 2b denotes a position regulating member integrally attached to both side surface portions 203a and 203b of the cover 2 to regulate the positions of the upper surface of the coater 1 and the upper surface of the cover 2 when the cover 2 is installed on the coater 1. . Reference numeral 204 denotes an air blocking member that is integrally attached to the inside of the rear surface portion that is not shown in the figure.

Since the cover 2 can be stably installed on the upper surface of the coater 1 by the position regulating members 202a and 202b and the air blocking member 204, the flow of air from the lower part of the coater can be blocked, so that the cover 2 is covered. It is possible to prevent the evaporation of the organic solvent from the upper surface of the coater, which is effective for coating stability. Other reference numerals have the same meaning as in FIG.

By installing a solvent evaporation preventing cover on the slide surface as shown in FIG. 2, evaporation of the solvent from the slide surface is suppressed, and an organic solvent-based coating liquid containing a solvent having a boiling point lower than that of water as a main component. When coating is performed with a coater, it is possible to prevent a failure due to drying of the coating liquid.

Originally, when an organic solvent-based coating liquid whose main component is a solvent having a boiling point lower than that of water is coated with a coater, the surroundings of the coating device are usually in a solvent atmosphere, and therefore the surrounding air is usually replaced frequently. It is being appreciated. In addition, since the latent heat of vaporization of an organic solvent system is about 1/3 that of water, it vaporizes violently when it has a low boiling point. Therefore, by installing a cover on the slide surface and filling the inside with an inert gas moistened with a similar organic solvent, the atmosphere on the slide surface becomes saturated with the organic solvent used for the coating solution, The evaporation of the organic solvent is suppressed. Furthermore, as described above, by saturating the inside of the cover with an organic solvent and maintaining the oxygen concentration at 8% or less,
There is virtually no possibility of flammable organic solvents burning.
Further, the inert gas supply port is provided above the slit on the slide surface that discharges the coating liquid that forms the uppermost layer of the coating film, and is connected to the portion that covers the rear surface of the slide surface, so that the specific gravity is high. The inert gas containing the organic solvent smoothly flows downward and flows out from the lower coater edge portion which is the only opening. This makes it possible to prevent the oxygen-containing atmosphere from mixing in from the only opening below and to increase the oxygen concentration, and to make the solvent concentration of the environment inside the cover uniform.

As a method of supplying the inert gas, it is preferable to blow it out evenly across the slide surface, and it is preferable to form a slit as a supply port of the inert gas in the header having a substantially coating width and to uniformly supply the gas. It is also possible to supply from a mesh plate in the header or a punch plate with many holes of about 1 to 5 mm, and if it does not affect the coating liquid flowing on the slide surface, it can be supplied from a circular pipe or a square duct. good.

FIG. 3 is a schematic cross-sectional view of the cover attached to the coater of FIG. 2, and FIG. 3 (a) is AA 'of FIG.
FIG. 3B is a schematic cross-sectional view taken along line B-B ′ of FIG. In the figure, reference numeral 205 denotes a rear surface portion of the cover 2, which has the same vertical length as the side surface portion and is integrated with the side surface portion. Reference numeral 206 denotes an inert gas supply port, which is connected to a portion that covers the rear surface of the slide surface. In this case, a slit is provided in the coating width direction, and an inert gas containing solvent vapor is supplied into the cover through the slit. As the inert gas containing solvent vapor, for example, nitrogen gas moistened with methyl ethyl ketone is preferably used. X indicates the distance between the slide surface and the inside of the top surface of the cover. As X, 2 to 20 mm is preferable and 2 m
If it is less than m, there is a danger that the coating solution laminated on the slide surface may come into contact with the inside of the top surface of the cover, and the wind velocity of the inert gas supplied to the surface of the slide surface may be undesirably high, while if it exceeds 20 mm. Because the volume covered with the slide surface and the cover becomes large, it takes time to fill this volume with an inert gas until the oxygen concentration becomes low, and the oxygen concentration is kept low (maintained below 8%). This is not preferable because the flow rate of the inert gas required for the above increases. In addition, the cover becomes large and the attaching and detaching work becomes difficult, which is not preferable. Y indicates the depth of the cover 2. If it is shorter than the slide surface of the coater 1, the area of the slide surface exposed to air becomes large,
It is not preferable because it causes coating failure. If it is too long, there is a risk of contact with the surface of the coating layer coated on the belt-shaped support, which is not preferable. Z indicates the vertical length of the side surface portion, 25
-40 mm is preferable. If it is less than 25 mm, it cannot be fixed on the upper surface of the coater, which is not preferable, and if it exceeds 40 mm, it becomes large and the workability at the time of attachment and detachment deteriorates, which is not preferable.

The width V of the cover 2 is preferably wider than the width S of the coater 1 by 5 to 10 mm, and if it is less than 5 mm, the workability at the time of attaching and detaching the cover is poor, and if it exceeds 10 mm, it is moistened with a solvent to be supplied. In addition, the amount of inert gas increases, which is not preferable. Other reference numerals have the same meaning as in FIG.

FIG. 4 is a schematic diagram showing an example of a coating state using a coater of a type different from that of FIG. 1 and provided with means for supplying an inert gas. Here, the connection form of the supply pipe 404 to the cover 2 in the inert gas supply system containing the solvent vapor of 4 is shown in a mode different from FIG. 1. Details of the supply pipe 404 for supplying the inert gas containing the solvent vapor to the inside of the cover 2 will be described with reference to FIG.

FIG. 5 is a schematic enlarged view of the cover 2 attached to the coater 1 and having a partially broken surface. The cover 2 formed wider in the width direction than the coater 1 is installed on the slide surface of the coater 1, and a supply pipe 404 for supplying an inert gas containing solvent vapor into the cover 2 is provided with a coater 1. Is a portion that covers the side surface of the slide surface (inside the side surface portions 203a and 203b of the cover 2) and is connected to the portion that covers the rear surface of the cover 2. Here, the inert gas containing the solvent vapor is introduced into the portion that covers the side surface of the slide surface of the coater 1 (inside the side surface portions 203a and 203b of the cover 2) via the connection portion between the supply pipe 404 and the cover 2. After that, the gas is supplied onto the slide surface of the coater 1 through an inert gas supply port formed in the cover 2 which is not shown in the figure. Other reference numerals and functions have the same meanings as in FIG.

FIG. 6 is a schematic sectional view of the cover attached to the coater of FIG. 5, and FIG. 6 (a) is CC 'of FIG.
FIG. 6B is a schematic cross-sectional view taken along line (b) of FIG. 5, and FIG. In the figure, the width R of the cover 2 is set to be wider than the width S of the coater 1, and 207a, 2
Reference numeral 07b denotes a contact surface portion between the cover 2 and the coater 1, which has a vertical length like the rear surface portion and is integrated with the rear surface portion. The inert gas containing the solvent vapor is sent from the supply pipe 404, and the connecting portion 4 formed in the portion covering the rear surface of the cover 2
It is introduced through 04a and 404b into a portion that covers the side surface of the slide surface of the coater 1 (inside both side surface portions 203a and 203b of the cover 2). Reference numeral 206 denotes an inert gas supply port on the slide surface, which is connected to a portion that covers the side surface of the slide surface. In this case, as an inert gas supply port,
Contact surfaces 207a between the left and right ends of the cover 2 and the coater 1,
A slit 207b is provided in the depth direction of the slide surface, and the inert gas containing the solvent vapor is supplied into the cover through the slit. Q indicates the depth of the cover 2, and is preferably 90 to 100% with respect to the sliding surface of the coater 1. If it is less than 90%, the area of the slide surface exposed to air becomes large, which leads to coating failure and is not preferable. 1
If it exceeds 00%, there is a risk of contact with the surface of the coating layer coated on the belt-shaped support, which is not preferable. The inert gas containing the solvent vapor is connected to the connecting portion 40 between the supply pipe 404 and the cover 2.
4a and 404b, and is introduced into a portion that covers the side surface of the slide surface of the coater 1 (inside both side surface portions 203a and 203b of the cover 2), and then from the inert gas supply port 206 formed in the cover 2 to the coater 1 Supplied on the slide surface of. Other reference numerals have the same meaning as in FIG.

The material used for the cover is not particularly limited as long as it does not become deformed or brittle when contacted with an organic solvent. Furthermore, if it is nonflammable and conductive, it is preferable in consideration of using a flammable organic solvent. Preferred materials for the cover include titanium, stainless steel,
Examples include metals such as aluminum, metal materials coated with polymer materials such as polyethylene resin and vinyl chloride resin, polymer materials such as polyethylene resin and vinyl chloride resin, glass, and glass coated with a conductive metal film. . Of course, it is also possible to make a combination of these materials.

The coating liquid usable in the present invention is a coating liquid using an organic solvent having a boiling point lower than that of water.
For example, it can be applied to the coating of coating liquids (including undercoating liquid, top coating liquid, back surface layer liquid, etc.) such as photosensitive materials, heat development recording materials, ablation recording materials, magnetic recording media, and steel plate surface treatments.

Examples of the solvent having a boiling point lower than that of water used for the coating liquid include methanol, ethanol, acetone, methyl ethyl ketone, ethyl acetate, tetrahydrofuran, acetonitrile and the like, and particularly preferable organic solvents are methanol, acetone, Methyl ethyl ketone may be mentioned.

The support used for applying the coating solution is not limited in kind, and may be paper, plastic film,
A metal sheet or the like can be used. Examples of the paper include resin-coated paper and synthetic paper. As the plastic film, a polyolefin film (for example, polyethylene film, polypropylene film, etc.), a polyester film (for example, polyethylene terephthalate film, polyethylene 2,6-naphthalate film, etc.), a polyamide film (for example, polyether ketone film etc.), Cellulose acetate (for example, cellulose triacetate etc.) etc. are mentioned.
An aluminum plate is a typical metal sheet. It can be used even if these have been subjected to surface treatment, undercoating, or the like, and can also be applied to coating on a support previously coated with another liquid. The thickness of the support used is also not particularly limited.

As described above, according to the present invention, when an organic solvent-based coating liquid containing a solvent having a lower boiling point than water as a main component is coated by a coater, orange pail-shaped coating unevenness caused by evaporation of the coating liquid is caused. There will be no breakdowns or muscle breakdowns, and it will be possible to manufacture recording materials with excellent quality and productivity.

[0067]

EXAMPLES The effects of the present invention will be shown below by way of example, but of course this example is merely an example, and the present invention is not limited thereto.

Example 1 An image recording medium containing organic silver was prepared according to the method described below. [Preparation of support] (Preparation of subbing support) Commercially available biaxially stretched and heat-fixed 100 μm thick and 1000 mm wide polyethylene terephthalate (hereinafter abbreviated as PET) film 8 W on both sides
/ M ² · min of corona discharge treatment, one side of which is coated with the undercoating coating solution a-1 below to a dry film thickness of 0.8 μm and dried to form an undercoating layer A-1. The antistatically processed undercoating coating liquid b-1 described below was applied to the opposite surface so that the dry film thickness was 0.8 μm, and dried to obtain an antistatically processed undercoating layer B-1. <Undercoating liquid a-1> Copolymer latex liquid of butyl acrylate (30 mass%), t-butyl acrylate (20 mass%), styrene (25 mass%), 2-hydroxyethyl acrylate (25 mass%) (Solid content 30%) 270 g (C-1) 0.6 g Hexamethylene-1,6-bis (ethyleneurea) 0.8 g Finish with water to 1 liter <Undercoating coating liquid b-1> Butyl acrylate (40% by mass) ), Styrene (20 mass%), glycidyl acrylate (40 mass%) copolymer latex liquid (solid content 30%) 270 g (C-1) 0.6 g hexamethylene-1,6-bis (ethyleneurea) 0 0.8 g of water is finished to 1 liter. Then, on the upper surface of the undercoat layer A-1 and the undercoat layer B-1,
A corona discharge of 8 W / m ² · min was applied, and the following undercoating upper layer coating liquid a-2 was dried to a thickness of 0.1 μm on the undercoating layer A-1.
As the undercoating upper layer A-2, the following undercoating upper layer coating liquid b-2 is provided on the undercoating layer B-1 to have an antistatic function so that the dry film thickness becomes 0.8 μm. It was applied as B-2. <Undercoating upper layer coating liquid a-2> Gelatin 0.4 g / m ² mass (C-1) 0.2 g (C-2) 0.2 g (C-3) 0.1 g Silica particles (average particle size 3 μm) 0.1 g Finish with water to 1 l <Undercoating upper layer coating liquid b-2> (C-4) 60 g (C-5) latex liquid (solid content 20%) 80 g Ammonium sulfate 0.5 g (C -6) 12g polyethylene glycol (mass average molecular weight 600) 6g Finish with water to 1 liter

[0069]

[Chemical 1]

[0070]

[Chemical 2]

(Heat Treatment of Undercoated Substrate) In the above-mentioned undercoat drying step of the undercoated substrate, the substrate was heated at 140 ° C. and then gradually cooled. (Preparation of backing layer-coated support) A back surface side coating solution having the following composition was applied on the undercoating upper layer B-2 of the above-prepared support using a known coating machine and dried at 60 ° C. 15
It was carried out for 1 minute to provide a support for coating the photosensitive layer and the protective layer. <Back-side coating liquid> Cellulose acetate (10% methyl ethyl ketone solution) 15 ml / m ² Dye-B 7 mg / m ² Dye-C 7 mg / m ² Matting agent: Monodispersity 15% Average particle size 10 μm Monodisperse silica 30 mg / _{^{m 2 C 9 H 17 -C 6}} H 4 -SO 3 Na 10mg / m 2

[0072]

[Chemical 3]

[Preparation of Photosensitive Layer and Protective Layer] A photosensitive layer coating solution and a protective layer coating solution to be coated on the undercoating upper layer A-2 of the support coated with the back layer were prepared. (Photosensitive Layer Coating Solution) (Preparation of Silver Halide Emulsion A) 7.5 g of inert gelatin and 10 mg of potassium bromide were dissolved in 900 ml of water to adjust the temperature to 35 ° C. and pH to 3.0, followed by silver nitrate 74
370 ml of an aqueous solution containing g and potassium bromide and potassium iodide in a molar ratio of (98/2) are equimolar to silver nitrate, [I
r (NO) Cl ₅ ] salt of 1 × 10 ^-6 mol per 1 mol of silver and rhodium chloride salt containing 370 ml of an aqueous solution containing 1 × 10 ^-4 mol per 1 mol of silver while maintaining pAg of 7.7. Method. Then 4
-Hydroxy-6-methyl-1,3,3a, 7-tetrazaindene was added and the pH was adjusted to 5 with NaOH,
Cubic silver iodobromide grains having an average grain size of 0.06 μm, a monodispersity of 10%, a variation coefficient of a projected diameter area of 8% and a [100] plane ratio of 87% were obtained. This emulsion was subjected to coagulation sedimentation using a gelatin coagulant and desalting, and then 0.1 g of phenoxyethanol was added to adjust the pH to 5.9 and pAg to 7.5 to obtain a silver halide emulsion. Further, the obtained silver halide emulsion was chemically sensitized with chloroauric acid and inorganic sulfur to obtain a silver halide emulsion A.

The monodispersity and the variation coefficient of the projected diameter area were calculated by the following equations. Monodispersity = (standard deviation of particle size) / (average value of particle size) × 1
00 Coefficient of variation of projected diameter area = (standard deviation of projected diameter area)
/ (Average value of projected diameter area) × 100 (Preparation of Na behenate solution) 32.4 g of behenic acid, 9.9 g of arachidic acid, and 5.6 g of stearic acid were dissolved in 945 ml of pure water at 90 ° C. Next, 98 ml of a 1.5 mol / L sodium hydroxide aqueous solution was added while stirring at high speed. Next, after adding 0.93 ml of concentrated nitric acid, the mixture was cooled to 55 ° C. and stirred for 30 minutes to obtain a sodium behenate solution. (Preparation of Preform Emulsion) 15.1 g of the silver halide emulsion A was added to the above sodium behenate solution and adjusted to pH 8.1 with a sodium hydroxide solution, and then 147 ml of a 1 mol / L silver nitrate solution was applied for 7 minutes. In addition, the mixture was further stirred for 20 minutes and the water-soluble salts were removed by ultrafiltration. The produced silver behenate had a mean particle size of 0.8 μm and a monodispersity of 8%. After forming the flocs of the dispersion, water was removed, and the mixture was further washed with water 6 times and removed, and then dried, and then 544 g of a solution of polyvinyl butyral (average molecular weight 3000) in methyl ethyl ketone (17% by mass) and 107 g of toluene. Was gradually added and mixed, and then dispersed by a media disperser to prepare a preform emulsion. (Preparation of coating solution for photosensitive layer) Preform emulsion 240 g Sensitizing dye-1 (0.1% methanol solution) 1.7 ml Pyridinium bromide perbromide (6% methanol solution) 3 ml Calcium bromide (0.1% methanol solution) ) 1.7 ml Antifoggant-2 (10% methanol solution) 1.2 ml 2- (4-chlorobenzoylbenzoic acid) (12% methanol solution) 9.2 ml 2-mercaptobenzimidazole (1% methanol solution) 11 ml Tri Bromomethylsulfoquinoline (5% methanol solution) 17 ml Developer-1 (20% methanol solution) 29.5 ml

[0075]

[Chemical 4]

(Preparation of Coating Solution for Bottom Layer) The coating solution for the photosensitive layer was diluted with the solvent methyl ethyl ketone (MEK) so that the viscosity was 30 × 10 ⁻³ Pa · s with a B-type viscometer, and the coating solution for coating was prepared. Application was performed as a lower slip layer. (Surface protection layer coating liquid) Acetone 35 ml / m ² MEK 17 ml / m ² Cellulose acetate 2.3 g / m ² Methanol 7 ml / m ² Phthalazine 250 mg / m ² 4-Methylphthalic acid 180 mg / m ² Tetrachlorophthalic acid 150 mg / m ² Tetrachlorophthalic anhydride 170 mg / m ² Matting agent: Monodispersity 10% Average particle size 4 μm Monodispersed silica 70 mg / m ² C ₉ H ₁₇ —C ₆ H ₄ —SO ₃ Na 10 mg / m ² [Coating process] ] The lowermost layer coating solution, the photosensitive layer coating solution and the surface protective layer coating solution were prepared using the slide coater shown in FIG.
Coating was carried out by simultaneous multilayering to obtain an image recording medium.

The cover on the slide surface has a height of 18 mm from the slide surface, the vertical length of the side and back surfaces of the cover is 35 mm, and the width is 8 mm wider than the width of the coater.
The depth is the same as the length of the slide surface of the coater, and the shape is almost covering the slide surface. The top surface of the cover has a thickness of 150 μm.
A thin aluminum plate was used and the frame was made of stainless steel.

As conditions for the slide coating method, the slide angle is about 20 degrees and the distance between the layers on the slide surface is 5 degrees.
0 mm, the application point of the slide lip is 10 degrees above the horizontal point of the back roll, and the application width is 1000 mm.
And the coating speed is 50 m / min and the degree of pressure reduction is 300 Pa.
The sample was prepared with the coating thickness and coating silver amount of each layer shown in Table 1.

[0079]

[Table 1]

The inert gas containing the solvent vapor is supplied in the widthwise slits provided above the slits on the slide surface for discharging the coating liquid for the surface protective layer forming the uppermost layer of the coating film. Supplied with nitrogen gas moistened with MEK. The method for supplying the slide coater of the type shown in FIG. 1 is called type A.

The inert gas was supplied by the type A supply method as shown in Table 2 by setting the oxygen concentration, the slide surface temperature, the coating solution temperature, the supply gas temperature, and the cover inner surface temperature.
Image recording medium samples 101 to 104 were prepared by coating.

The nitrogen gas used for the samples 101 to 103 was produced by using a membrane separation type nitrogen gas generator, and the nitrogen concentration was 99%.
% Nitrogen gas was moistened at a predetermined supply temperature and MEK vapor pressure and then supplied into the cover. Sample 104 was supplied with only the atmosphere, not nitrogen gas. And ME in the cover
The supply flow rate of the atmosphere was adjusted so that the K concentration became a solvent concentration of 1/4 or less of the lower explosion limit.

The oxygen concentration inside the cover is measured by Riken Keiki Co., Ltd.
Diaphragm galvanic cell oxygen analyzer GD-F4A (not shown)
It was measured at.

As a method of obtaining the relative humidity, the saturated vapor pressure was estimated from the cover internal environmental temperature and the Antoine vapor pressure formula. The coefficient of Antoine of MEK is R. C
Reed et al., Translated by Mitsuho Hirata, Tuna Hill Book Co., Ltd.
It is quoted from "Handbook for Estimating Physical Properties of Gas and Liquid", 3rd edition.

The vapor pressure was measured by sampling the gas supplied to the cover (not shown), and using a GC-323S gas chromatograph manufactured by GL Science, a TCD type MEK in nitrogen gas was used.
The concentration (volume%) is measured, and from the MEK concentration (volume%), according to the Magat's law and Dalton's law,
The MEK vapor pressure was estimated. [Image exposure and heat development treatment] Obtained samples 101 to 1
04 was exposed with a laser sensitometer having a semiconductor laser of 810 nm. Then, heat development processing was performed at 110 ° C. for 15 seconds using an automatic developing machine having a heat drum. At that time, exposure and development were performed in a room where the humidity was adjusted to 23 ° C. and 50 RH%.

The developed samples 101 to 104 were evaluated for coating unevenness on the coated surface on an X-ray photograph observing device (Shakasten). The obtained results are shown in Table 2.

[0087]

[Table 2]

As is clear from Table 2, application was performed under the condition that the oxygen concentration in the cover was 8% or less by supplying the inert gas moistened with MEK in the relative humidity range of 50 to 100%. It can be seen that in Samples 101 and 102, coating unevenness on the coating surface did not occur, and coating failure was improved.
However, it can be seen that the samples 103 and 104 are not suitable for practical use because unevenness occurs due to the drying of the uppermost layer.

Example 2 Sample 201 was obtained in the same manner as Sample 101, except that the slide type coater shown in FIG. 4 described below was used to supply the inert gas.

The type A is the same as that of FIG. 1 except for the means for supplying the inert gas containing the solvent vapor. As a means of supplying an inert gas containing solvent vapor, nitrogen gas moistened with MEK is introduced into both side surfaces of the cover, and then nitrogen gas moistened with MEK is moved in the depth direction of the sliding surface of both side surfaces of the cover. It was supplied onto the slide surface of the coater through a slit that was a supply port provided. The method of supplying the slide type coater of the type shown in FIG.

The sample 101 of Example 1 and the sample 201 obtained as described above were uniformly exposed with a laser sensitometer having a semiconductor laser of 810 nm. After that, using an automatic processor having a heat drum, the temperature is 1.5 at 110 ° C.
Was subjected to a heat development treatment so that the optical density became. At that time, exposure and development were performed in a room where the humidity was adjusted to 23 ° C. and 50 RH%.

The developed samples 101 and 201 were evaluated for coating unevenness on the coated surface on an X-ray photograph observing device (Shakasten), and the optical transmission density was measured as follows, and the standard deviation of density distribution was observed. The results obtained are shown in Table 3. (Measurement of Optical Transmission Density) The optical transmission density was measured by using a spectrophotometer UV-1200 manufactured by Shimadzu Corporation to measure the transmission density of the unexposed portion of the sample at 400 nm at 200 points at equal intervals in the width direction. did. This is shown as the concentration distribution standard deviation (%). The concentration distribution standard deviation (%) is a value calculated from the following equation.

Concentration distribution standard deviation (%) = standard deviation of 200 points / concentration average value of 200 points × 100 Coating conditions, coating properties, and values of standard deviation of concentration distribution in width direction (%) are shown. 3 shows.

[0094]

[Table 3]

As is clear from Table 3, the sample 201 using the type B for supplying the inert gas was good, like the sample 101 using the type A, without any abnormalities such as unevenness in drying. On the other hand, with respect to the concentration distribution, the sample 201 obtained by supplying the inert gas from both sides of the slide surface as in the type B has a relatively good fluctuation range, but the type A
The sample 101 obtained by supplying the inert gas in (1) was better with less fluctuation.

Example 3 Sample 301 was obtained in the same manner as Sample 101, except that the inner surface temperature of the cover of the slide coater was 21 ° C. The oxygen concentration in the cover was 10%.

The sample 101 and the sample 301 obtained as described above were uniformly exposed with a laser sensitometer having a semiconductor laser of 810 nm. Then, using an automatic processor having a heat drum, heat development processing was performed at 110 ° C. so that the optical density became 1.5. At that time, exposure and development were performed in a room where the humidity was adjusted to 23 ° C. and 50 RH%.

The developed samples 101 and 301 were evaluated for coating unevenness on the coated surface on an X-ray photograph observing device (Schaucasten). The results obtained are shown in Table 4.

[0099]

[Table 4]

As is clear from Table 4, the sample 101 in which the inner surface temperature of the cover is maintained higher than the ambient temperature (here, the temperature of the supply gas) covered with the slide surface and the cover has no coating failure and is well coated. You can see that it is a surface. However, in Sample 301, repellency was recognized on the coated surface. This was a malfunction due to condensation of the solvent on the inner surface of the cover on the slide surface, and dripping of the condensed solvent.

[0101]

According to the present invention, when an organic solvent-based coating liquid containing a solvent having a boiling point lower than that of water as a main component is coated by a simultaneous multi-layer slide coater, a coating failure typified by orange pail is prevented. Outbreak is improved, and not only the basic coating performance is high, but also the safety is improved, resulting in a remarkably excellent effect. Also, by preventing solvent evaporation from the slide surface,
It is also possible to minimize the deformation of the coater die due to the temperature change and to reduce the change in the film thickness distribution in the lateral direction over time. Further, it is possible to prevent dew condensation due to the evaporated solvent on the surface of the cover that covers the slide surface, and to prevent application failure due to the drop of the condensed solvent dripping on the slide surface.

[Brief description of drawings]

FIG. 1 is a schematic view showing an example of a coating state using a coater provided with a means for supplying an inert gas.

FIG. 2 is a schematic enlarged view of the cover attached to the coater and having a partially broken surface.

3 is a schematic sectional view of a cover attached to the coater of FIG. 2, (a) is a schematic sectional view taken along the line AA ′ of FIG. 2, and (b) is a sectional view taken along the line BB ′ of FIG. It is the schematic sectional drawing which followed.

FIG. 4 is a schematic view showing an example of a coating state using a coater provided with a means for supplying an inert gas different from that of FIG.

FIG. 5 is a schematic enlarged view of the cover attached to the coater and having a partially broken surface.

6 is a schematic cross-sectional view of the cover attached to the coater of FIG. 5, (a) is a schematic cross-sectional view taken along the line CC ′ of FIG. 5, and (b) is a line DD ′ of FIG. It is the schematic sectional drawing which followed.

[Explanation of symbols]

1 Simultaneous multi-layer slide type coater (coater) 2 cover 3 Coating liquid supply system 4 Inert gas supply system containing solvent vapor 5 back rolls 6 Belt-shaped support 7 coating layer 8 decompression room 101a, 101b, 101c, 101d bar 102a, 102b, 102c slits 105a, 105b, 105c, 105d Sliding surface 201a, 201b, 201c, 201d Engagement member 202a, 202b Position regulating member 203a, 203b Both sides of the cover 204 Air blocking member 404 Supply pipe X Distance between slide surface and inside of cover top Depth of Y, Q cover Vertical length of Z side V and R cover width S coater width

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) G03F 7/16 501 501 G03F 7/16 501 5D112 G11B 5/842 G11B 5/842 Z F term (reference) 2H023 EA01 2H025 AA18 DA01 EA04 4D075 AC02 AC05 AC16 AC17 AC72 AC80 BB56Y BB57Y CA48 DA03 DB01 DB07 DB18 DB31 DB33 DB36 DB48 DB53 DC28 EA06 EA45 EB22 EB23 EB32.

Claims (8)

[Claims] 1. A back roll holds an opposite surface of coating,
Two or more slits for separately extruding a coating liquid containing a polymer resin into a solvent containing an organic solvent having a boiling point of 40 to 85 ° C., and three or more slits constituting the slits, to a belt-shaped support that is continuously conveyed. A slide type coater for simultaneous multi-layering, which is composed of the above-mentioned bar and simultaneously coats two or more coating layers, the coater is provided with a cover for covering the slide surface, the side surface and the rear surface, and the oxygen concentration in the cover is 8 %, And a means for supplying an inert gas moistened to a relative humidity of 50 to 100% by a solvent having the highest mass contained in the coating liquid. Slide type coater. 2. An inert gas supply port is provided above a slit on a slide surface that discharges a coating liquid that forms a coating film uppermost layer, and is connected to a portion of the cover that covers the rear surface of the slide surface. The slide-type coater for simultaneous multi-layering according to claim 1, wherein 3. The simultaneous multi-layer slide coater according to claim 1, wherein the means for supplying the inert gas is provided so as to be connectable to a portion of the cover that covers the side surface of the slide surface. 4. A back roll holds the opposite side of the coating,
Two or more slits for separately extruding a coating liquid containing a polymer resin into a solvent containing an organic solvent having a boiling point of 40 to 85 ° C., and three or more slits constituting the slits, to a belt-shaped support that is continuously conveyed. In the simultaneous multi-layer slide type coater, which is composed of the above-mentioned bar and applies two or more coating layers at the same time, a cover for covering the slide surface, the side surface and the rear surface is formed on the coater, and the cover inner surface facing the slide surface. Is maintained at a temperature higher than the ambient temperature covered by the slide surface and the cover. 5. The simultaneous multilayer slide according to claim 1, wherein the coating solution is an organic solvent-based coating solution containing a solvent having a boiling point lower than that of water as a main component. Type coater. 6. The simultaneous multi-layer slide coater according to claim 1, wherein the cover is detachably provided. 7. A method for producing a recording material, which comprises applying a coating liquid using the slide coater for simultaneous multilayering according to claim 1 to produce a recording material. 8. The method for producing a recording material according to claim 7, wherein the recording material is a heat developable silver salt medium.