JP2003126761A - Coating method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a coating method by which coating failure are suppressed against the disturbance given on a die main body or a coating liquid. SOLUTION: In the coating method of applying >=2 kinds of the coating liquids discharged from each slit of multilayer slot dies supported from the rear side by a backup roll and mounted to face the surface of a continuously travelling supporting body by (x) layers ((x) represents integers of >=2) simultaneously on the supporting body, when the slit in the uppermost stream based on the supporting body travelling direction as reference is expressed by S1 , the slit in the next downstream is expressed by S2 ,... and the slit in the downmost stream is expressed by Sx and the specified flow rate in the n-th slit Sn is Qn ml/sec, a slit gap is Gn μm and the discharge width is L mm, the shear rate γn sec<-1> in a specific conditional expression satisfies the specific conditional expression in the adjacent slits Sn and Sn-1 .

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a coating method, and more specifically, it applies a coating solution discharged from a slit of a slot die installed facing a backup roll on the surface of a continuously running support. The present invention relates to a coating method (so-called extrusion coating method, extrusion type coating method).

[0002]

2. Description of the Related Art Conventionally, there are various coating methods in a coating step for coating a coating liquid on a support. The coating method is roughly classified into two. One is a pre-metering type coating method in which the coating liquid is discharged in an amount to form a required coating liquid film and the coating liquid is coated on the support. This is a post-measurement type coating method in which the coating liquid is discharged onto a support and then the surplus is removed by some scraping means.

Examples of the post-measurement type coating system include a blade type coating system, an air knife type coating system and a wire bar type coating system. Examples of the pre-weighing type coating method include a slot type (also referred to as extrusion type) coating method, a curtain type coating method, and a slide type coating method.

For coating in the manufacturing process of photographic light-sensitive materials, the slot type coating method and the slide type coating method are used because of high coating accuracy, high quality, and difficulty in receiving the influence of the support (wrinkles, cracks, etc.). It was often adopted.

The coating device in these coating systems is
It is composed of a so-called die for supplying the coating liquid to form a coating liquid film uniformly on the support and a backup roll for uniformly holding the surface of the support which continuously runs. These coating methods are ones in which the coating liquid is discharged from the slit of the die and a bead (liquid pool) is formed in the gap between the portion called the edge and the continuously running support surface held by the backup roll. Yes, the die is a combination of two or more blocks, and has a supply port for supplying the coating liquid, a manifold for temporarily storing the supplied coating liquid in the width direction, and a slit for uniformly discharging the coating liquid from the manifold. This is a coating method which has a single layer and a multilayer coating depending on the number of combinations of blocks.

Regarding the extrusion type coating method, JP-A-56-95363 and JP-A-50-142643.
A number of techniques are disclosed, including a single-layer coating method disclosed in each of the publications, and a multi-layer coating method disclosed in JP-A-45-12390 and 46-236.

In recent years, the demand for a multilayer slot-type coating method in which two or more different coating liquids are simultaneously coated by the slot-type coating method has been increasing with the enhancement of the functionality and quality of the coating-type material.

[0008]

In such a simultaneous multi-layer coating method using a multi-layer slot die, the disturbance of the coating film that occurs between liquid-liquid interfaces is often a problem. The disturbance of the coating film that occurs between the liquid and liquid interfaces causes a disorder of the appearance of the finished coating film, which is referred to as an orange peel failure.

Multi-layer coating using a multi-layer slot die is a coating method which has been widely used in recent years, and the behavior of the coating liquid between liquid-liquid interfaces is not known. Therefore,
Empirically and experimentally, the conditions were adjusted so that the liquid-liquid interface would not be disturbed according to the coating liquid used.

The object of the present invention is to solve the problems even when some vibration is applied to the slot die or the coating solution itself, or when a slight difference in physical properties (for example, viscosity or surface tension) occurs in the process of preparing the coating solution. It is an object of the present invention to provide a coating method in which the disturbance of the liquid-liquid interface is unlikely to occur, that is, the coating failure can be suppressed against the disturbance applied to the die body or the coating liquid.

[0011]

The above object of the present invention can be achieved by the following constitution. 1. X layers of two or more different coating liquids discharged from each slit of a multi-layer slot die that is installed facing the surface of a support that is continuously supported and supported by a back-up roll. 2 or more integer)
In the coating method of simultaneously applying to the support, when the most upstream slit is S ₁ , the one downstream slit is S ₂ , and the most downstream slit is S _x with reference to the support traveling direction, The specified flow rate at the n-th slit S _n is Q _n ml
/ Sec, the slit gap is G _n μm, and the discharge width is L mm, the shear rate γ _n se represented by the following equation (1)
A coating method characterized in that c ^-1 satisfies the following formula (2) in the adjacent slits S _n and S _n-1 .

[0012]

[Equation 7]

However, in the equation (1), n = 1 to x

[0014]

[Equation 8]

However, in the equation (2), n = 2 to x 2. X layers of two or more different coating liquids discharged from each slit of a multi-layer slot die that is installed facing the surface of a support that is continuously supported and supported by a back-up roll. 2 or more integer)
In the coating method of simultaneously applying to the support, when the most upstream slit is S ₁ , the one downstream slit is S ₂ , and the most downstream slit is S _x with reference to the support traveling direction, The specified flow rate at the n-th slit S _n is Q _n
ml / sec, slit gap G _n μm, discharge width Lm
m and the support traveling speed is Um / sec, the discharge speed v _n m / sec represented by the following formula (3) satisfies the following formula (4) in the adjacent slits S _n and S _n-1 . A coating method characterized by the above.

[0016]

[Equation 9]

However, in the equation (3), n = 1 to x

[0018]

[Equation 10]

However, in the equation (4), n = 2 to x 3. X layers of two or more different coating liquids discharged from each slit of a multi-layer slot die that is installed facing the surface of a support that is continuously supported and supported by a back-up roll. 2 or more integer)
In the coating method of simultaneously applying to the support, when the most upstream slit is S ₁ , the one downstream slit is S ₂ , and the most downstream slit is S _x with reference to the support traveling direction, The coating liquid pressure measured value P _n MPa after being ejected from the n-th slit S _n and applied and 300 seconds or more after the start of application is calculated by the following formula (5) in the adjacent slits S _n and S _n-1 . A coating method characterized by satisfying:

[0020]

[Equation 11]

However, in the equation (5), n = 2 to x4. X layers of two or more different coating liquids discharged from each slit of a multi-layer slot die that is installed facing the surface of a support that is continuously supported and supported by a back-up roll. 2 or more integer)
In the coating method of simultaneously applying to the support, when the most upstream slit is S ₁ , the one downstream slit is S ₂ , and the most downstream slit is S _x with reference to the support traveling direction, The edge of the downstream bar forming the n-th slit S _n has a distance of d _n μm from the support at the downstream end, and the edge of the upstream bar forming the most upstream slit S ₁ has a support at the downstream end. When the distance is d ₀ μm, the specified flow rate at the n-th slit S _n is Q _n ml / sec, the discharge width is L mm, and the support traveling speed is U m / sec, the adjacent slits S _n and S _{n- 1.} A coating method according to _1, wherein the following formula (6) is satisfied.

[0022]

[Equation 12]

However, in the formula (6), n = 1 to x The present inventor diligently studied a coating method for suppressing the disturbance that may occur at the liquid-liquid interface formed between different coating liquids. And, as a result of experiments, they found that the following method was effective. (A) The difference in the shear rate that each coating liquid receives in the adjacent slits has the relationship shown in Expression (2). (B) The difference between the coating liquid discharge speeds in the adjacent slits has the relationship shown in Expression (4). (C) The difference between the pressures applied to the coating liquids in the adjacent slits has the relationship shown in Expression (5). (D) In the adjacent slits, the distance between the downstream side bar edge forming each slit and the support has the relationship shown in Expression (6).

In the present invention, in a multi-layer coating using a slot die, in order to suppress coating failure (referred to as "skin skin failure") due to turbulence generated at the liquid-liquid interface, only the relationship between layers is specified. .

Conventionally, various coating conditions (coating liquid viscosity, etc.)
The invention focused on the conditions of the coating device (dimensional relationship of the slot die, relationship between the back roll and the slot die, etc.) may have been applied to the multi-layer coating using the slot die, but the present invention does such coating. The present invention has been completed by paying attention to the relationship between the coating liquid layers instead of the conditions as a whole.

[0026]

DETAILED DESCRIPTION OF THE INVENTION The details of the present invention will be described below. FIG. 1 shows a schematic diagram of the vicinity of a coating device in a general multi-layer slot coating system. The support 1 is held by a backup roll 2 through a support cleaning means (not shown) (web cleaner, etc.) from an unwinding unit (not shown), runs, passes through a coating film drying chamber (not shown), and is wound up. At that time, the coating liquids 4-1, 4-2, and 4-3 are coated on the support 1 by the slot die 3 arranged so as to face the backup roll 2. Although not shown here, it is generally equipped with a mechanism for removing or preventing the thick film portion at the coating start portion and coating end portion which causes problems such as roll stains due to undried coating film in the coating step. Is.

The support 1 used in the present invention is not limited in kind, and may be paper, plastic film, metal sheet, etc.
Anything can be used. Examples of the paper include resin-coated paper and synthetic paper. As the plastic film, a polyolefin film (eg, polyethylene film, polypropylene film, etc.), a polyester film (eg, polyethylene terephthalate film, polyethylene 2,6-naphthalate film, etc.), a polyamide film (eg, polyether ketone film etc.) , Cellulose acetate film (eg, cellulose triacetate film) and the like. An aluminum plate is a typical metal sheet. Further, there is no particular limitation on the thickness and width of the support used.

The coating liquids 4-1, 4-2, 4-3 are respectively sent from the tank 8 by the liquid sending pump 7, pass through the filtering device 6 and the pressure sensor 10, and then are conducted to the slot die 3. . The slot die 3 has a stage 5 for moving the coating position and a standby position (a retreat position for performing coating preparation work), and a coating liquid receiver for collecting or discharging the coating liquid flowing out at the standby position. A chamber 9 is provided. Further, the filtration of the coating liquid by the filtration device is preferably carried out at least once through a filter medium having an absolute filtration accuracy or quasi-absolute filtration accuracy of 5 to 50 μm. The coating liquid receiving chamber is provided at a position where it does not come into contact with the support 1 wound around the backup roll 2 when it is at the coating position, and the pressure is reduced during coating according to the properties of the coating liquid and the necessity of coating. Sometimes Also, the multi-layer slot die 3
It is preferable that one of the slit intermediate extension lines of (1) faces the center of the backup roll.

Coating liquids 4-1 and 4-used in the present invention
There are no particular restrictions on 2, 4-3, for example, coating liquids for general and industrial silver halide photosensitive materials, coating liquids for heat-sensitive materials, coating liquids for photothermographic materials, or polymer materials for organic solvents, Examples thereof include a liquid dissolved in water or the like, a pigment dispersion liquid, a colloidal dispersion liquid, and the like.

FIG. 2 shows a sectional view of the slot die 3 at the central portion in the coating width direction. The slot die 3 is usually composed of a combination of two or more blocks (the combination is by a bolt, a hydraulic jack, etc.). The slot die 3 has a slit 3-3 for uniformly spreading the coating liquid in the width direction of the support, a manifold 3-4 for storing the coating liquid therein, and a supply port for conducting the coating liquid in the manifold 3-4. 3-5, an edge that faces the backup roll 2 and forms a bead (liquid pool). The edge is divided into an upstream side 3-2 and a downstream side 3-1 with a slit in between.

The gap value of the slit is usually 0.05 mm to 2
It is determined from the physical properties such as the viscosity of the coating liquid in the range of mm. However, the variation in the gap value in the coating width direction is preferably 2% or less. The size of the supply port is arbitrary, and its position is usually the center in the width direction of the slot die coating. Edge is upstream 3-2
And the downstream side 3-1 may have the same length or different lengths.
The length is usually set in the range of about 0.5 mm to 3 mm. Further, the predetermined coating position can be set arbitrarily, but can be set arbitrarily depending on the pressure reduction in the coating liquid receiving chamber 9, the physical properties of the coating liquid, the coating property, and the like. The narrowest gap between the support 1 on the backup roll 2 and the slot die edges 3-1 and 3-2 is usually 5 times or less the thickness of the coating liquid film applied on the support.

Next, a coating method in a general extrusion type coating method will be described. While the slot die is in a standby position that is sufficiently distant from the coating position, the pump 7 feeds the coating liquid at a specified flow rate to perform preparatory work such as slit cleaning and edge cleaning, and then the support 1 travels at a specified speed. After that, the stage 5 is moved to move the slot die 3 to a predetermined coating position to start coating. In this case, when the preparation operation is started immediately after finishing the preparation work, or when the preparation work takes a certain time to stabilize the outflow state of the coating liquid or after the slit cleaning and the edge cleaning are completed, the coating liquid remains at the specified flow rate. May be drained for a certain period of time.

A coating film is formed on the support 1 immediately after the start of coating, and the distance between the edges 3-1 and 3-2 and the bead portion between the support 1 is adjusted depending on the case. At this time, an operator visually observes the coating film, inspects for defects such as streaks, and if there is no problem, a normal coated product is obtained from that position.

Even during the subsequent coating, it is general to check the occurrence of coating failure by monitoring the flow rate of the coating liquid, inspecting the surface of the coating film with a trouble gauge, or visually inspecting the operator.

Further, in order to eliminate the difference between the temperature of the coating liquid and the temperature of the slot die 3 and keep them constant, the tank 8 is usually equipped with a jacket, a heat exchanger is provided in the middle of the pipe, and a slot is used. Insulating water may be passed through the die 3. However, in most of these cases, only the heat retaining water having a constant temperature is circulated.

In the present invention, the above-mentioned pressure sensor has a measurement interval of 1 Hz or more and a measurement accuracy of ± of the maximum measurable pressure.
Use 0.5% or more.

Next, the coating method of the present invention will be described.
In order to realize the required performance for each of the coating liquids 4-1, 4-2, 4-3 applied in multiple layers,
The flow rate Q _{n with} respect to the traveling speed U of the support 1 is determined. Based on this flow rate Q _n , the shear rate S _{n of} each slit 3-3 based on the equation (1) and the slit 3- based on the equation (3).
3 Each slit gap G _n is determined so that the respective discharge speeds v _n satisfy the expressions (2) and (4). However, in this case, it is necessary to determine the coating liquid in consideration of the loads on the filtering device 6, the pump 7, and the piping due to the pressure received when the coating liquid passes through the slit 3-3 during liquid feeding. That is, it is necessary to pay attention to the pressure resistance of the filter material contained in the filtration device 6, the pressure resistance of the pipe, and the pressure resistance of the pump for sending the specified flow rate, and to determine the slit gap G _{n in} consideration of safety.

It has been found that by satisfying the expression (2) or the expression (4), it is possible to suppress the coating failure due to the disturbance of the liquid-liquid interface. When the formulas (2) and (4) are not satisfied, the frequency of occurrence of coating failure due to the liquid-liquid interface disturbance is higher than that in the case where the formulas (2) and (4) are not satisfied. Further, when the thresholds of both formulas are largely deviated, coating streaks or the like are generated on the entire surface, which makes coating impossible.

Further, each bar constituting each slit is adjusted so as to satisfy the equation (6) based on the above Q _n . Slot die edges 3-1 and 3-2 at this time
FIG. 3 shows the distance relationship between the backup roll 2 and the support 1 supported by the backup roll 2. FIG. 3 shows the case of simultaneous coating of three layers, in which the slit is S ₁ in order from the upstream side in the support running direction,
S ₂ and S ₃ , and the distance from the support 1 is as shown in FIG. When the positional relationship between the edges 3-1 and 3-2 and the support 1 satisfies the expression (6), the occurrence frequency of the coating failure due to the liquid-liquid interface disturbance is remarkably higher than that when the positional relationship is not satisfied. Can be suppressed. Further, when the range of the formula (6) is largely deviated, the coating may be unstable and a normal coating may not be obtained.

The coating solutions 4-1, 4-2, and 4-3 of the respective layers have a sufficiently uniform outflow, and after the coating is started, the coating position and angle of the slot die 3 are adjusted so as to satisfy the formula (5). To do. However, at this time, since the pressure measurement value which is sufficiently stable coating is used, 300 seconds or more are allowed to elapse after the coating is started. Since naturally there is a possibility that loss will occur in this work, in the case of the same coated product, it is possible to carry out the operation under the same conditions after performing only once. Further, if the coating failure due to the turbulence at the liquid-liquid interface does not occur during the 300 seconds, it can be used as a product as a matter of course. When Expression (5) is also satisfied, the occurrence frequency of coating failure due to liquid-liquid interface disturbance can be significantly suppressed as compared with the case where Expression (5) is not satisfied.

[0041]

EXAMPLES The effects of the present invention will be specifically described below with reference to examples, but the present invention is not limited to these embodiments.

In the example, the three-layer simultaneous coating slot die used in the description of FIGS. 1 to 3 was used. The coating liquid for each of the three layers is the following coating liquid described in the examples of JP-A-2001-201817, and the photosensitive layer coating liquid A from the upstreammost slit S ₁ from the upstream side in the support traveling direction and the upstreammost slit, respectively. The photosensitive layer coating liquid B and the surface protective layer coating liquid flow out from the slits S ₂ between the most downstream slits.

That is, the preparation of the photosensitive layer coating liquid A, the photosensitive layer coating liquid B and the surface protective layer coating liquid was as follows. << Preparation of Photosensitive Silver Halide Emulsion A >> (Solution A1) Phenylcarbamoylated gelatin 88.3 g Compound A (10% aqueous methanol solution) 10 ml Potassium bromide 0.32 g Water to make 5429 ml. (Solution B1) 0.67 mol / L aqueous silver nitrate solution 2635 ml (Solution C1) potassium bromide 51.55 g potassium iodide 1.47 g Water is adjusted to 660 ml. (Solution D1) Potassium bromide 154.9 g Potassium iodide 4.41 g Iridium chloride (1% solution) 0.93 ml Make up to 1982 ml with water.

(Solution E1) 0.4 mol / L aqueous solution of potassium bromide Silver potential control amount (solution F1) Potassium hydroxide 0.71 g Water to make 20 ml. (Solution G1) 56% acetic acid aqueous solution 18.0 ml (Solution H1) anhydrous sodium carbonate 1.72 g Make up to 151 ml with water. _{A: HO (CH 2 CH 2} O) n (CH (CH 3) CH 2 O) 17 (CH 2 CH 2 O) m H (m + n = 5~7)

JP-B-58-58288 and 58-58
Using a mixing stirrer shown in No. 289, 1/4 amount of the solution (B1) and 4 parts of the solution (C1) were added to the solution (A1).
While controlling at 5 ° C. and pAg of 8.09, the mixture was added for 4 minutes and 45 seconds by the simultaneous mixing method to perform nucleation. After 1 minute, the total amount of solution (F1) was added. During this period, the pAg was adjusted appropriately using the solution (E1). After 6 minutes, 3/4 amount of the solution (B1) and the total amount of the solution (D1) were added by the simultaneous mixing method over 14 minutes and 15 seconds while controlling 45 ° C. and pAg 8.09. After stirring for 5 minutes, the temperature was lowered to 40 ° C., the entire amount of the solution (G1) was added, and the silver halide emulsion was precipitated. The supernatant was removed, leaving 2000 ml of the sedimented portion, 10 liters of water was added, and after stirring, the silver halide emulsion was sedimented again. Settling part 15
The supernatant was removed, leaving 00 ml, and 10 liters of water was further added. After stirring, the silver halide emulsion was allowed to settle.
After removing the supernatant liquid, leaving 1500 ml of the sedimented portion, the solution (H1) was added and the temperature was raised to 60 ° C.
Stir for minutes. Finally adjust the pH to 5.8,
Add water so that the amount of silver is 1161 g per mol,
A photosensitive silver halide emulsion A was obtained. This emulsion has an average grain size of 0.058 μm and a grain size variation coefficient of 12
%, And the [100] plane ratio was 92%, which was a monodisperse cubic silver iodobromide grain.

<< Preparation of powdered organic silver salt A >> In 4720 ml of pure water, 130.8 g of behenic acid and 67.7 of arachidic acid are added.
g, stearic acid 43.6 g, and palmitic acid 2.3 g were dissolved at 80 ° C. Next, 540.2 ml of a 1.5 mol / L sodium hydroxide aqueous solution was added, and concentrated nitric acid 6.9 m
After adding l, it was cooled to 55 ° C. to obtain a fatty acid sodium solution.

The temperature of this fatty acid sodium solution is 55 ° C.
While maintaining the above temperature, 45.3 g of the above photosensitive silver halide emulsion A and 450 ml of pure water were added and stirred for 5 minutes. Then 1
702.6 ml of a mol / L silver nitrate aqueous solution was added over 2 minutes and stirred for 10 minutes to obtain an organic silver salt dispersion. After that, the obtained organic silver salt dispersion was transferred to a water washing container, deionized water was added thereto, and the mixture was stirred and then allowed to stand to separate the organic silver salt dispersion by flotation to remove the water-soluble salts below. After that, washing with deionized water and drainage were repeated until the conductivity of the drainage reached 2 μS / cm, and after centrifugal dehydration was performed, the obtained cake-shaped organic silver salt was washed with a flash dryer, a jet jet dryer (Seishin). (Manufactured by a company), depending on the operating conditions of the nitrogen gas atmosphere and the hot air temperature at the dryer inlet,
It was dried until the water content became 0.1% to obtain dried organic silver salt A of organic silver salt. An infrared moisture meter was used to measure the water content of the organic silver salt composition.

<< Preparation of Preliminary Dispersion A >> Polyvinyl butyral powder (manufactured by Monsanto: Butvar B-
79) 14.57 g was dissolved in 1457 g of MEK, and VM
A-GETZMANN Dissolver DISPERMA
Powdered organic silver salt A5 while stirring with TCA-40M type
A preliminary dispersion liquid A was prepared by gradually adding 00 g and thoroughly mixing them.

<< Preparation of Photosensitive Emulsion Dispersion Liquid 1 >> Using a pump, the predispersion liquid A was used so that the residence time in the mill was 1.5 minutes. ) Filled with 80% of the internal volume of the media type disperser DISPERMAT SL-C12EX type (VM
A-GETZMANN), and the peripheral speed of the mill is 8 m /
Photosensitive Emulsion Dispersion Liquid 1 was prepared by dispersing in s.

<< Preparation of Stabilizer Solution >> 1.0 g of stabilizer--
1. 0.31 g of potassium acetate to methanol 4.97 g
To prepare a stabilizer solution.

[0051]

[Chemical 1]

<< Preparation of Infrared Sensitizing Dye Solution A >> Sensitizing Dye 1,
0.05 mol of each of the following (1) -27 and (2) -30
/ Agmol, and a mixed solution of 5-methyl-2-mercaptobenzimidazole (mixing ratio 1: 250 to 45
0:20, 0.1% MEK solution with sensitizing dye, 31.3 m
l) was dissolved in the dark to prepare an infrared sensitizing dye solution A.

<< Preparation of additive liquid a >> 1,1 as a developer
-Bis (2-hydroxy-3,5-dimethylphenyl)
27.98 g of 2-methylpropane and 1.54 g of 4
-Methylphthalic acid, 0.48 g of the above infrared dye 1 in ME
It was dissolved in K110 g to give an additive liquid a.

<< Preparation of Additive Liquid b >> 1.78 g each of antifoggant 1 and printout inhibitor, and further 3.43 g
Was dissolved in 40.9 g of MEK to prepare an additive solution b.

<< Preparation of Additive Liquid c >> 5.0 g of silver saving agent H
-94 was melt | dissolved in MEK45.0g and it was set as the addition liquid c.

[0056]

[Chemical 2]

<< Preparation of Coating Solution A for Photosensitive Layer >> The photosensitive emulsion dispersion 1 was prepared under an inert gas atmosphere (97% nitrogen).
While stirring 50 g and 15.11 g of MEK at 21 ° C.
Incubate, add 1000 μl of chemical sensitizer S-5 (0.5% methanol solution), and 2 minutes later, antifoggant 1 (1
390 μl of 0% methanol solution) was added and stirred for 1 hour. Further calcium bromide (10% methanol solution) 49
After adding 4 μl and stirring for 10 minutes, a gold sensitizer Au-5 corresponding to 1/20 mol of the chemical sensitizer was added, and further 2
Stir for 0 minutes. Subsequently, 167 ml of the stabilizer solution was added and stirred for 10 minutes, and then 1.32 g of the infrared sensitizing dye solution A was added and stirred for 1 hour. Then, the temperature was lowered to 13 ° C., and the mixture was further stirred for 30 minutes. While keeping the temperature at 13 ° C, polyvinyl butyral (Butvar B-79:
After adding 13.31 g of the above) and stirring for 30 minutes, 1.084 g of tetrachlorophthalic acid (9.4% MEK solution)
Was added and stirred for 15 minutes. While continuing to stir,
Addition liquid a of 12.43 g, isocyanate compound of 1.6 ml (manufactured by Mobay, Desmodur N330
The photosensitive layer coating liquid A was obtained by sequentially adding the 10% MEK solution of 0), 4.27 g of the addition liquid b, and stirring.

[0058]

[Chemical 3]

<< Preparation of Photosensitive Layer Coating Liquid B >> In the atmosphere of inert gas (nitrogen 97%), the above-mentioned photosensitive emulsion dispersion liquid 1 was prepared.
While stirring 50 g and 15.11 g of MEK at 21 ° C.
Incubate, add 1000 μl of chemical sensitizer S-5 (0.5% methanol solution), and 2 minutes later, antifoggant 1 (1
390 μl of 0% methanol solution) was added and stirred for 1 hour. Further calcium bromide (10% methanol solution) 49
After adding 4 μl and stirring for 10 minutes, a gold sensitizer Au-5 corresponding to 1/20 mol of the chemical sensitizer was added, and further 2
Stir for 0 minutes. Subsequently, 167 ml of the stabilizer solution was added and stirred for 10 minutes, and then 1.32 g of the infrared sensitizing dye solution A was added and stirred for 1 hour. Then, the temperature was lowered to 13 ° C., and the mixture was further stirred for 30 minutes. While keeping the temperature at 13 ° C, polyvinyl butyral (Butvar B-79;
After adding 13.31 g of the above) and stirring for 30 minutes, 1.084 g of tetrachlorophthalic acid (9.4% MEK solution)
Was added and stirred for 15 minutes. While continuing to stir,
Addition liquid a of 12.43 g, isocyanate compound of 1.6 ml (manufactured by Mobay, Desmodur N330
0) 10% MEK solution, 4.27 g of additive solution b, 10.
The photosensitive layer coating liquid B was obtained by sequentially adding 0 g of the additive liquid c and stirring.

<< Preparation of Matting Agent Dispersion >> Cellulose Acetate Butyrate (Eastman Chemical)
Company: CAB171-15) 7.5 g MEK42.5
g of calcium carbonate (Specia)
Light Minerals: Super-Pfl
ex200) (5 g) was added, and the mixture was dispersed with a dissolver type homogenizer at 8000 rpm for 30 minutes to prepare a matting agent dispersion liquid.

<< Preparation of Coating Solution for Surface Protective Layer >> While stirring 865 g of MEK (methyl ethyl ketone), 96 g of cellulose acetate butyrate (CAB171-15: supra), polymethylmethacrylic acid (Rohm & Haas Company: Paraloid) A-21) 4.5 g, vinyl sulfone compound (HD-1) 1.5 g, benzotriazole 1.0 g, fluorine-based activator (Surflon KH40: supra)
1.0 g was added and dissolved. Next, 30 g of the above-mentioned matting agent dispersion liquid was added and stirred to prepare a surface protective layer coating liquid.

HD-1: (CH ₂ = CHSO ₂ CH ₂ ) ₂ CHOH

In any of the following examples, the coating speed U is 1
m / sec, coating width, that is, discharge width L of each layer is 500 m
m and the wet coating amount was 5 with the photosensitive layer coating liquid A.
0 ml / m ^2, the photosensitive layer coating solution B with 50 ml / m ^2, is carried out coating was fed by a flow rate Q such that 10 ml / m ² with a protective layer coating solution. The supports used are all commercially available thickness 1
It is a PET film having a size of 00 μm and a width of 600 mm. The coating film after coating is dried at 80 ° C. for 2 minutes.

Then, coating was carried out under the conditions as described below to prepare a sample (hereinafter referred to as sample), and an evaluation of the skin-like defects caused by the disturbance of the liquid-liquid interface was evaluated. In addition, in the condition comparisons 1 to 3, the distance between the slot die edge and the support is fixed according to the condition of the sample number 17 in the condition comparison 4. Further, in the condition comparison 4, the slit gap of the slot die is fixed to the condition of the sample number 12 in the condition comparison 3.

In the evaluation, the sample was exposed and developed so that the density was 1.5 under the condition that the entire surface was uniform, and then the flesh-like defects were visually judged. It was set to 1 point and 10 points were evaluated. <Comparison of Conditions 1> Coating was performed in a slit gap as shown in Table 1 below, and the coated sample obtained was visually evaluated. As shown in Table 1, when the shear rate satisfies the expression (2), it is possible to suppress the orange peel defect.

[0066]

[Table 1]

<Comparison of Conditions 2> Coating was carried out in a slit gap as shown in Table 2 below, and the coating sample obtained was visually evaluated. As shown in Table 2, the discharge skin speed was able to satisfy the expression (4), and thus the skin texture failure could be suppressed.

[0068]

[Table 2]

<Comparison of Conditions 3> Coating was carried out in a slit gap as shown in Table 3 below, and the coated sample obtained was visually evaluated. Table 3 also shows the pressure measurement value after 300 seconds or more have elapsed from the start of coating. As shown in Table 3, when the measured pressure value satisfies the expression (5), it is possible to suppress the yuzu skin condition failure.

[0070]

[Table 3]

<Condition Comparison 4> Coating samples obtained by coating at the distance between the slot die edge and the support as shown in Table 4 below were visually evaluated. As shown in Table 4, when the distance between the edge and the support satisfies the expression (6), the yuzu flesh-like failure could be suppressed.

[0072]

[Table 4]

[0073]

In the coating method according to the present invention, for example, when some vibration is applied to the slot die or the coating liquid itself, or a slight difference in physical properties (for example, viscosity and surface tension) occurs in the process of preparing the coating liquid. Even in such a case, the liquid-liquid interface is less likely to be disturbed. That is, according to the present invention, the coating failure can be suppressed against the disturbance applied to the die body or the coating liquid.

[Brief description of drawings]

FIG. 1 is a schematic view of a coating apparatus and its vicinity in a general multi-layer slot coating method.

FIG. 2 is a cross-sectional view of the slot die at the central portion in the coating width direction.

FIG. 3 is a sectional view showing a distance relationship between a slot die edge and a support.

[Explanation of symbols]

1 support 2 backup roll 3 slot die 3-1 Downstream edge 3-2 Upstream edge 3-3 Slit 3-4 Manifold 3-5 Supply port 4,4-1,4-2,4-3 coating liquid 5 stages 6 Filtration device 7 Liquid transfer pump 8 tanks 9 Coating liquid receiving chamber 10 Pressure sensor

Claims (4)

[Claims] 1. A x-layer of two or more different coating liquids discharged from each slit of a multi-layer slot die which is installed to face a surface of a support which is continuously run while being supported by a back-up roll. (However, x is an integer of 2 or more) In the coating method of simultaneously coating the support, the most upstream slit is S ₁ , the one downstream slit is S ₂ , with respect to the support traveling direction, and the most downstream. Is defined as S _x , the prescribed flow rate at the n-th slit S _n is Q _n ml / sec, the slit gap is G _n μm, and the discharge width is L mm. A coating method characterized in that a shear rate γ _n sec ⁻¹ that satisfies the following formula (2) is satisfied in the adjacent slits S _n and S _n-1 . [Equation 1] However, in the formula (1), n = 1 to x However, in the formula (2), n = 2 to x 2. An x-layer of two or more different coating liquids discharged from each slit of a multi-layer slot die which is installed so as to face the surface of a support which is continuously supported while being supported from the back surface by a backup roll. (However, x is an integer of 2 or more) In the coating method of simultaneously coating the support, the most upstream slit is S ₁ , the one downstream slit is S ₂ , with respect to the support traveling direction, and the most downstream. _Sx is the slit, the prescribed flow rate at the n-th slit S _n is Q _n ml / sec, the slit gap is G _n μm, the discharge width is L mm, and the support traveling speed is Um / sec. discharge speed v _n m / sec as represented by the following formula (3) is,
A coating method characterized in that the following formula (4) is satisfied in adjacent slits S _n and S _{n- 1} . [Equation 3] However, in the equation (3), n = 1 to x However, in the formula (4), n = 2 to x 3. Support from the back side by a backup roll
Is installed facing the surface of the support that is running continuously.
Is discharged from each slit of the multi-layer slot die
X layers of two or more different coating liquids (where x is 2 or more)
Is an integer of 1).
The most upstream slit is S based on the running direction of the body.₁, So
S one of the downstream slits₂,,,, the most downstream slit
To S_xAnd the nth slit S_nIs discharged from
It has been applied and after 300 seconds have passed since the start of application
Coating liquid pressure measurement value P_nMPa is the adjacent slit S_nWhen
S _n-1Is characterized in that the following expression (5) is satisfied.
Application method. [Equation 5] However, in the formula (5), n = 2 to x 4. An x-layer of two or more different coating liquids discharged from each slit of a multi-layer slot die, which is supported by a back-up roll from the back surface and runs continuously on the surface of a support. (However, x is an integer of 2 or more) In the coating method of simultaneously coating the support, the most upstream slit is S ₁ , the one downstream slit is S ₂ , with respect to the support traveling direction, and the most downstream. Is defined as S _x , the distance between the edge of the downstream bar forming the n-th slit S _n and the support at the downstream end is d _n μ
m, the edge of the upstream side bar constituting the most upstream slit S ₁ , the distance from the support at the downstream end is d ₀ μm, the specified flow rate at the _nth slit S _n is Q _n ml / sec, and the discharge width is Lm
m, and the traveling speed of the support is Um / sec, the following formula (6) is satisfied in the adjacent slits S _n and S _n−1 . [Equation 6] However, in the formula (6), n = 1 to x