JP2005329308A - Coating method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a coating method for eliminating coating troubles which tend to occur at the front of coating in coating with a high-viscosity coating solution containing a volatile solvent by a coating device using a simultaneous multi-layer slide type coater and thereby achieving high production efficiency. <P>SOLUTION: The method uses a coating device having a backup roll winding, carrying and guiding a strip support to be carried continuously, a simultaneous multi-layer slide type coater coating two or more coating solutions in the form of beading onto the support in the vicinity of the backup roll and a decompression chamber arranged upstream to the beading and in the vicinity of the outer peripheral surface of the backup roll. The coating solutions include at least two coating solutions containing a volatile solvent and an auxiliary coating solution and are coated with the degree of decompression of the decompression chamber at the front of coating set to be 50-600 Pa higher than that during coating under steady conditions. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a backup roll that guides and conveys a belt-like support that is continuously conveyed, a simultaneous multi-layer slide type coater that forms a bead on the belt-like support and forms a plurality of coating solutions on the belt-like support, and a bead The present invention relates to a coating method using a coating apparatus having a decompression chamber provided close to the outer peripheral surface of a backup roll on the upstream side.

  2. Description of the Related Art Conventionally, the following two coating methods are known as a method for applying a coating solution to a belt-like support (hereinafter also referred to as a support) that runs continuously. One is a coating application method, blade coating method, air knife, after which excess coating solution than the required coating solution film formation amount is discharged onto the support in advance, and then the excess is removed by some scraping means Examples thereof include a coating method, a wire bar coating method, a gravure coating method, a reverse coating method, and a reverse roll coating method.

  The other is an extrusion coating method using an extrusion type coater, which is a pre-weighing type coating method in which a coating liquid is discharged by an amount that forms a required coating liquid film and the coating liquid is applied onto a support. And a slide coating method using a slide type coater and a curtain coating method.

  Recently, in the fields of medical treatment and printing plate making, waste liquid resulting from wet processing of image forming materials has become a problem in terms of workability. In recent years, reduction of processing waste liquid has been strongly desired from the viewpoint of environmental conservation and space saving. It is rare. Therefore, photothermographic materials capable of forming an image only by applying heat have been put into practical use and are rapidly spreading in the above fields.

  Photothermographic materials (hereinafter, also simply referred to as photothermographic materials) have been proposed for a long time. For example, U.S. Pat. Nos. 3,152,904 and 3,457,075; “Dry Silver Photographic Material” by Morgan, D.M. Morgan and B.M. “Thermal Processed SilverSystems” by Shely (Imaging Processes and Materials) Nebelte 8th edition, Sturges, Wall. Walworth), edited by A. Shepp, page 2, 1969) and the like.

  This heat-developable material is processed by a heat-development processing apparatus that forms an image by applying stable heat of 80 to 140 ° C. to a heat-developable material usually called a heat development processor. Since this heat developing material is characterized in that fixing is not performed, the silver halide and organic silver salt remaining in the unexposed portion remain in the heat developing material as they are without being removed.

  In the production of heat-developable materials, a method is known in which a photosensitive layer and a protective layer formed on the photosensitive layer and a protective layer formed on the photosensitive layer are coated simultaneously with the photosensitive layer in an undried state. No. 15173, US Pat. No. 5,849,363 and the like.

  For example, a slide coater is widely used for simultaneous multilayer coating of the heat developing material. The slide type coater is used in coating apparatuses for photosensitive materials, magnetic recording materials and the like because it can be applied simultaneously at high speed, thin film, and multilayer.

  In these slide type coaters, a coating liquid reservoir called a bead is formed between a coater tip (also simply referred to as an edge or a lip) and a belt-like support (also referred to as a web) that is continuously conveyed, and coating is performed via the bead. It is known that

  In a slide type coater in which application is performed through such a bead, the stability of the bead greatly affects the stability of application, so a decompression chamber is provided on the upstream side where the bead is formed. It is known to increase the stability of the bead by applying a pressure difference up and down and pulling the bead downward. In addition, the setting of the gap between the lip and the web, the coating environment conditions such as the temperature and the coating speed, the properties of the coating liquid such as the viscosity and the surface tension, and the coating film thickness are also affected.

  For example, in the case of heat development materials, when simultaneous multi-layer coating is performed with a slide type coater using a high-viscosity volatile solvent-containing coating solution, the relationship between physical properties of the coating solution between layers is greatly affected, and the coating speed is further increased. As the film becomes thinner or the film thickness becomes thinner, it becomes difficult to stabilize the bead. It is known that when the bead is unstable, application failures such as muscle failure, tailing failure, and liquid shortage occur. Recently, there is a tendency to increase the viscosity of the coating liquid from the viewpoint of measures against drying unevenness due to the drying air in the drying process. Using a high-viscosity coating liquid, a bead at the time of application by a slide type coater is used. Many studies have been made to stabilize it.

  For example, a coating solution having a viscosity of 5 to 40 mPa · s is used, and at the beginning of coating, coating is started at a degree of decompression higher than the steady-state decompression degree. Thus, a method for stabilizing the bead is known (for example, see Patent Document 1).

  However, in the technique described in Patent Document 1, when a high-viscosity coating liquid having a viscosity of 0.2 to 2.0 Pa · s is used, the bead pressure (the coating liquid for the bead portion necessary for forming the bead) is used. If the internal pressure is high and the degree of decompression is changed, the pressure inside the coating liquid in the bead forming part changes slowly, so it takes time to stabilize the bead part. It is connected.

  When the coating liquid for the lowermost layer has a viscosity of 0.5 to 100 mPa · s and contains a volatile solvent thereon and a viscosity of 300 mPa · s is applied, the gap between the coater lip and the web is determined by the coating speed. Related methods are known (for example, 120 to 175 μm when the coating speed is 5 m / min, 300 to 500 μm when the coating speed is 25 m / min, and 300 to 600 μm when the coating speed is 50 m / min). (For example, see Patent Document 2).

  However, in the technique described in Patent Document 2, when a high-viscosity coating liquid having a viscosity of 0.2 to 2.0 Pa · s is used, the viscosity of the coating liquid is high. There is a risk that it may become difficult to form a bead of the coating solution for the uppermost layer that comes into contact, and the coating may become unstable. When applying using a slide type coater, poor wettability at the top of application (part of the width cannot be applied) is likely to occur, but it is difficult to adjust the viscosity of the intermediate layer in terms of performance. Therefore, wetting is a situation where the entire width can be applied naturally after about 100 seconds from the start of application, so that there is a lot of loss of the top sample, and the production is in a state of low production efficiency. .

From such a situation, a backup roll that guides and conveys the belt-like support that is continuously conveyed, and a simultaneous multi-layer slide type coater that forms a bead on the belt-like support in the vicinity of the backup roll and coats it. In a coating method using a coating apparatus having a decompression chamber provided close to the outer peripheral surface of the backup roll on the upstream side of the bead, when applying a high-viscosity coating liquid containing a volatile solvent, Development of a coating method that eliminates the coating failure that occurs and has high production efficiency is desired.
JP-A-62-212451 JP 2004-50007 A

  The present invention has been made in view of the above circumstances, and its purpose is to apply at the beginning of application when applying a high-viscosity coating liquid containing a volatile solvent by a coating apparatus using a simultaneous multi-layer slide type coater. It is to provide a coating method that eliminates failures and has high production efficiency.

  The above object of the present invention has been achieved by the following constitution.

(Claim 1)
A backup roll that guides and conveys the belt-like support that is continuously conveyed;
A simultaneous multi-layer slide type coater that forms a bead on the belt-shaped support in the vicinity of the backup roll to form a bead;
In a coating method using a coating apparatus having a decompression chamber provided close to the outer peripheral surface of the backup roll on the upstream side of the bead,
The coating solution has at least two volatile solvent-containing coating solutions and a coating auxiliary coating solution,
An application method, wherein the application is performed with the degree of vacuum in the decompression chamber at the top of application being 50 to 600 Pa higher than the degree of vacuum during steady-state application.

(Claim 2)
A backup roll that guides and conveys the belt-like support that is continuously conveyed;
A simultaneous multi-layer slide type coater that forms a bead on the belt-shaped support in the vicinity of the backup roll to form a bead;
In a coating method using a coating apparatus having a decompression chamber provided close to the outer peripheral surface of the backup roll on the upstream side of the bead,
The coating solution has at least two volatile solvent-containing coating solutions and a coating auxiliary coating solution,
A coating method, characterized in that at the start of coating, the advance speed of the simultaneous multilayer slide type coater to the coating position of the belt-like support on the backup roll is set to 5 to 100 mm / sec.

(Claim 3)
A backup roll that guides and conveys the belt-like support that is continuously conveyed;
A simultaneous multi-layer slide type coater that forms a bead on the belt-shaped support in the vicinity of the backup roll to form a bead;
In a coating method using a coating apparatus having a decompression chamber provided close to the outer peripheral surface of the backup roll on the upstream side of the bead,
The coating solution has at least two volatile solvent-containing coating solutions and a coating auxiliary coating solution,
A coating method, characterized in that an interval between the simultaneous multi-layer slide type coater at the start of coating and the belt-like support on the backup roll is made 50 to 150 μm narrower than a spacing at the time of steady-state coating.

(Claim 4)
The decompression degree at the coating head of the decompression chamber is set to 50 to 300 Pa higher than the decompression degree at the time of steady-state application, and the interval between the simultaneous multi-layer slide type coater and the belt-like support on the backup roll is set in the steady-state application. The coating method according to claim 2, wherein the coating is made narrower by 50 to 150 μm than the time interval.

(Claim 5)
4. The coating method according to claim 2 or 3, wherein the coating is applied with a degree of vacuum at the top of coating in the decompression chamber being 50 to 300 Pa higher than the degree of vacuum during steady-state coating.

(Claim 6)
The coating method according to claim 3, wherein the simultaneous multi-layer slide type coater moves the advance speed at a rate of 10 to 100 mm / sec to the coating point of the belt-like support on the backup roll at the start of coating.

(Claim 7)
The said coating liquid for coating assistance is discharged from the lowest slit, uses the same solvent as the adjacent coating liquid, and has a viscosity of 0.5 to 50 mPa · s. Application method.

(Claim 8)
The coating method according to claim 1, wherein the coating liquid containing the volatile solvent has a viscosity of 0.2 to 2.0 Pa · s.

(Claim 9)
The coating method according to claim 1, wherein the coating solution containing the volatile solvent is a coating solution for a photothermographic material.

  When applying a high-viscosity coating solution containing a volatile solvent with a coating device using a simultaneous multi-layer slide type coater, it is possible to eliminate the coating failure that occurs at the top of the coating and provide a coating method with high production efficiency and stable. Production became possible.

  Embodiments according to the present invention will be described with reference to FIGS. 1 to 3, but the present invention is not limited thereto.

  FIG. 1 is a schematic view of a slide coating method in which a bead is formed and coated using a slide type coater. (A) of FIG. 1 is a schematic diagram of a slide coating method in which a bead is formed and coated on a holding portion of a support having a coating opposite surface held by a back roll using a slide type coater. FIG. 1B is an enlarged schematic view of the slide type coater shown in FIG.

  In the figure, 1 is a slide type coater, 2 is a back roll, and 3 is a belt-like support that is continuously conveyed from upstream to downstream (in the direction of the arrow in the figure).

  Reference numeral 101 denotes a bar constituting the slide type coater 1. The number of bars is not fixed, but can be increased or decreased depending on the number of layers to be applied. This figure has shown the case where the slide type | mold coater 1 is comprised with four bar | burr 101a-100d. The back roll refers to a transport roll installed on the opposite side of the belt-like support 3 with the slide coater 1 and the belt-like support 3 sandwiched between them. Due to its large influence, it is made of a metal with a large diameter of 200 mm or more.

  Reference numeral 102 denotes a slit which is an outlet of the coating liquid made by the bar 101. The number of slits varies depending on the number of bars constituting the slide type coater, but is usually 2 to 20. The slide type coater 1 shown in the figure is composed of four bars 101a to 100d, and is a slide type coater for simultaneous multi-layering having three slits 102a to 102c formed between the four bars 101a to 100d. Show. Reference numeral 103 denotes a slide surface on which the coating liquid discharged from the slit 102 flows, and has the slide surfaces 103a to 103c of the bars 101a to 100d.

  Reference numeral 104 denotes an application width provided at both ends of the slide surface 103 in order to regulate the spread in the width direction of the application liquid flowing down on the slide surface 103 constituted by the bars 101a to 100d constituting the slide type coater 1. The restriction plate is shown. It is preferable that the coating width regulating plate 104 can control the temperature depending on the type of coating solution.

  The coating liquid supply channel formed between the bars 101a to 101d through the supply pipes 403a to 403c of the coating liquid prepared in the preparation tanks 401a to 401c of the coating liquid supply system 4 by the liquid feeding pumps 402a to 402c. The coating liquid supplied to the pockets 107a to 107c through the sections 108a to 108c and discharged from the slits 102a to 102c is applied onto the coating liquid discharged from the slit 102a. And the coating liquid discharged from the slits 102 c is placed on the slide surfaces 103 a to 103 c whose application widths are restricted by the application width restriction plate 104, and the beads 5 are passed through the lip portions 105. It is formed and applied to the holding portion of the belt-like support 3 which is held and conveyed by the back roll 2 and is opposite to the application surface.

  In general, coating is performed using the slide coater shown in the figure through the following steps. 1) The coating auxiliary liquid is discharged from the lowermost slit, and the flow rate is determined. 2) A coating liquid for image formation is discharged from an intermediate slit, and the flow rate is determined. 3) A non-image forming coating solution is discharged from the uppermost slit, and the flow rate is determined. 4) When the step 3) is completed, with the coating liquid discharged from each slit, the slide coater and the decompression chamber are moved from the standby position to the coating position and coated on the belt-like support on the back roll. Apply liquid.

  Reference numeral 6 denotes a decompression chamber provided at the lower portion of the slide type coater 1 for stabilization of application, 601 denotes a suction pipe, and 602 denotes a drainage pipe. The degree of decompression in the decompression chamber at the start of coating needs to be 50 to 600 Pa higher than the degree of decompression during steady-state coating. When the degree of reduced pressure is less than 50 Pa relative to the degree of reduced pressure at the time of application in a steady state, it is not preferable that the formation of the bead is not stable due to insufficient bead pressure, resulting in a problem of poor wetting.

  When the degree of vacuum exceeds 600 Pa compared to the degree of vacuum during steady-state application, it takes time to form beads over the entire width of the application width, so it takes time to apply the full width, resulting in a large loss. Therefore, it is not preferable.

  Reference numeral 7 denotes a coating layer coated on the support. W1 indicates an application point at which the coating liquid is applied to the support 3 by the slide type coater 1, and a position of 0 to 20 degrees above the horizontal axis that normally passes through the center of the back roll is preferable.

  The slide type coater 1 moves from a standby position (not shown) toward the application point W1 at the start of the start application, and is movably mounted so as to return to the standby position (not shown) after the application is completed. It is put on.

  As an example of the application of the coating solution for the photothermographic material using the slide type coater 1 shown in this figure, the coating auxiliary coating solution is discharged from the slit 102a disposed at the lowermost portion and disposed in the middle. A method of discharging a coating solution for forming an image containing a volatile solvent from the slit 102b, and a method of discharging a coating solution for a surface protective layer containing a volatile solvent from the slit 102c provided at the top. .

  In this case, it is desirable that the coating auxiliary coating solution uses the same solvent as the adjacent coating solution, and the coating auxiliary coating solution has a viscosity of 0.5 to 50 mPa · s. The viscosity of the coating liquid for image formation is preferably as high as 0.2 to 0.4 Pa · s. Further, the viscosity of the coating liquid for the surface protective layer is 1 to prevent unevenness from being blown by the drying air during drying. A high viscosity of 2 Pa · s is preferred.

  When applying a high-viscosity coating solution using a slide type coater as shown in this figure, when applying the coating head, the degree of vacuum is set higher by 50 to 600 Pa than the steady-state pressure reduction. An effect is obtained.

  1) The formation of the bead at the top of the coating became stable, stable coating at the top was possible, loss due to coating failure at both ends was reduced, and production efficiency could be improved.

  2) The formation of the bead at the top of the coating is stable, the top can be stably coated, and there is no deterioration in quality due to the formation of an undried coating film due to the thick coating film at both ends. Production became possible.

  FIG. 2 is a schematic diagram showing the flow distribution of the high-viscosity coating liquid flowing down the slide surface of the slide type coater shown in FIG.

  In the figure, H (L) indicates the vicinity of the coating width regulating plate and the high-viscosity coating liquid in contact (range of 1 to 2 cm from the coating width regulating plate in the width direction of the slide surface). I (K) is a portion sandwiched between the vicinity H portion (L) where the coating width regulating plate and the high viscosity coating solution are in contact with the normal flow rate portion J (from the coating width regulating plate to the width direction of the slide surface). In the range of 2 to 3 cm). J indicates a normal flow rate portion.

  In the vicinity portion H (L) where the coating width regulating plate and the high viscosity coating liquid are in contact, the high viscosity coating liquid is brought into contact with the end surface of the coating width regulating plate, and the high viscosity coating liquid is regulated by the surface tension. The flow rate increases with respect to the flow rate of the high-viscosity coating liquid that is drawn toward the plate side and flows down the normal flow rate portion J.

  In the portion I (K) sandwiched between the vicinity portion H (L) where the coating width regulating plate and the high viscosity coating liquid are in contact with the normal flow rate portion J, the coating width regulating plate and the high viscosity coating liquid are in contact with each other. By pulling the high-viscosity coating liquid both in the vicinity portion H (L) and the normal flow rate portion J, the flow rate is minimized.

  FIG. 3 is an enlarged schematic plan view of a portion indicated by S in FIG.

  In the figure, G indicates the distance between the tip of the slide surface of the slide coater at the start of application and the application position of the belt-like support on the backup roll. Other reference numerals are the same as those in FIG. The distance G needs to be 50 to 150 μm narrower than the distance between the tip of the slide surface of the slide coater at the time of steady application and the application position of the belt-like support on the backup roll. When the distance is less than 50 μm, the bead pressure is insufficient and the formation of the bead is not stable, so that a failure to get wet occurs, which is not preferable. When the distance exceeds 150 μm, the bead pressure becomes too high and application is impossible.

  As shown in this figure, when applying a high-viscosity coating solution, when applying the coating head at the start of coating, the tip of the slide surface of the slide coater and the coating position of the belt-like support on the backup roll The following effects can be obtained by setting the interval 50 to 150 μm narrower than the gap in the steady state.

  1) The formation of the bead at the top of the coating became stable, stable coating at the top was possible, loss due to coating failure at both ends was reduced, and production efficiency could be improved.

  2) The formation of the bead at the top of the coating is stable, the top can be stably coated, and there is no deterioration in quality due to the formation of an undried coating film due to the thick coating film at both ends. Production became possible.

  At the start of application, the forward speed for moving the slide coater to the application position of the belt-like support on the backup roll (in the direction of the arrow in the figure) is 5 to 100 mm / sec. When the advance speed is less than 5 mm / sec, the tip of the coating solution flowing down the coating slide surface flows to the decompression chamber side due to the reduced pressure, and therefore the volume of the coating solution forming the bead portion decreases, thereby reducing the bead. This is not preferable because it cannot be formed and cannot be applied. When the advance speed exceeds 100 m / sec, the leading liquid-attached portion becomes too thick, so that an undried coating film is formed, which leads to a decrease in quality.

  As shown in this figure, when applying a high-viscosity coating solution, the slide coater is placed at the coating position of the belt-like support on the backup roll at the start of coating by setting the advance speed at 5 to 100 mm / sec. The effect is obtained.

  1) The formation of the bead at the top of the coating became stable, stable coating at the top was possible, loss due to coating failure at both ends was reduced, and production efficiency could be improved.

  2) The formation of the bead at the top of the coating is stable, the top can be stably coated, and there is no deterioration in quality due to the formation of an undried coating film due to the thick coating film at both ends. Production became possible.

  The amount of wet coating (film thickness immediately after coating) of the coating aid for coating according to the present invention is preferably 1 to 15 μm. When the wet amount (film thickness immediately after application) is less than 1 μm, there may be a case where the application width regulation plate is not evenly supplied to the end surface on the slide surface side. When the wet amount (film thickness immediately after coating) exceeds 15 μm, the flow rate of the low-viscosity coating solution and the flow rate of the high-viscosity coating solution may be lost, and the frequency of occurrence of coating unevenness may increase.

  As the solvent used in the low-viscosity coating liquid according to the present invention, it is preferable to use the same solvent as the solvent used in the coating liquid.

  The coating solution according to the present invention is not particularly limited as long as it is an organic solvent-based coating solution, but a high-volatility having a boiling point of 90 ° C. or lower and a viscosity of 100 mPa · sec or higher is used. This is particularly effective when the photothermographic material is used.

  Examples of these coating solutions for photothermographic materials include coating solutions described in JP-A Nos. 2000-198757, 2000-15173, 2001-201817, 2001-215562, 2001-109101, and the like. .

  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 examples.

Example 1
In accordance with the method shown below, a photosensitive layer coating solution and a surface protective layer coating solution containing an organic silver component were prepared.

<Coating solution for photosensitive layer>
<< Preparation of silver halide emulsion A >>
After dissolving 7.5 kg of inert gelatin and 10 g of potassium bromide in 900 L of water to adjust the temperature to 35 ° C. and pH to 3.0, bromide with a molar ratio of (98/2) to 370 L of an aqueous solution containing 74 kg of silver nitrate 370 L of an aqueous solution containing 1 × 10 ⁻⁶ mol of potassium, potassium iodide and [Ir (NO) Cl ₅ ] salt per mol of silver and 1 × 10 ⁻⁶ mol of rhodium chloride per mol of silver was added to pAg 7.7. Added by the controlled double jet method. Thereafter, 4-hydroxy-6-methyl-1,3,3a, 7-tetrazaindene was added, the pH was adjusted to 5 with NaOH, the average particle size was 0.06 μm, the monodispersity was 10%, the projected diameter Cubic silver iodobromide grains having an area variation coefficient of 8% and a [100] face ratio of 87% were obtained. This emulsion was coagulated and precipitated using a gelatin flocculant and desalted, and then 100 g of phenoxyethanol was added to adjust the pH to 5.9 and pAg of 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 silver halide emulsion A.

  The coefficient of variation of the monodispersity and the projected diameter area was calculated by the following equation.

Monodispersity (%) = (standard deviation of particle size) / (average value of particle size) × 100
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 >>
In 945 L of pure water, 32.4 kg of behenic acid, 9.9 kg of arachidic acid, and 5.6 kg of stearic acid were dissolved at 90 ° C. Next, 98 L of a 1.5 mol / L sodium hydroxide aqueous solution was added while stirring at high speed. Next, 0.93 L of concentrated nitric acid was added, and the mixture was cooled to 55 ° C. and stirred for 30 minutes to obtain a sodium behenate solution.

<Preparation of preform emulsion>
15.1 kg of the above silver halide emulsion A was added to the above sodium behenate solution and the pH was adjusted to 8.1 with a sodium hydroxide solution. Then, 147 L of a 1 mol / L silver nitrate solution was added over 7 minutes, and the mixture was further stirred for 20 minutes. Water-soluble salts were removed by ultrafiltration. The resulting silver behenate was a grain having an average grain size of 0.8 μm and a monodispersity of 8%. After forming the floc of the dispersion, water was removed, water was washed 6 times, water was removed and dried, and then 544 kg of a methyl ethyl ketone solution (17% by mass) of polyvinyl butyral (average molecular weight 3000) and 107 kg of toluene. Were gradually added and mixed, and then dispersed at 27.6 MPa with a media disperser to prepare a preform emulsion.

<< Preparation of coating solution for photosensitive layer >>
Preform emulsion 240kg
Sensitizing dye-1 (0.1% methanol solution) 1.7 L
Pyridinium Promide Perbromide (6% methanol solution) 3L
Calcium bromide (0.1% methanol solution) 1.7L
Antifoggant-1 (10% methanol solution) 1.2L
2- (4-Chlorobenzoylbenzoic acid (12% methanol solution))
9.2L
2-mercaptobenzimidazole (1% methanol solution) 11L
Tribromomethylsulfoquinoline (5% methanol solution) 17L
Developer-1 (20% methanol solution) 29.5L

<Coating liquid for surface protective layer>
<< Preparation of coating solution for surface protective layer >>
Methyl ethyl ketone 52L
Cellulose acetate 2.3kg
Methanol 7L
Phthalazine 250g
4-methylphthalic acid 180g
150 g of tetrachlorophthalic acid
170 g of tetrachlorophthalic anhydride
Matting agent: 10% monodispersion average particle size 4 μm monodispersed silica
70g
_{C 9 H 19 -C 6 H 4} -SO 3 Na 10g
The preparation amount of the photosensitive layer coating solution and the surface protective layer coating solution was prepared according to the coating amount, with the above preparation amount as one unit.

<Coating liquid for coating assistance>
<Preparation of coating solution for coating assistance>
Polyvinyl butyral (average molecular weight 3000) was used as a binder, and the amount of methyl ethyl ketone was changed and dissolved as necessary.

<Preparation of slide type coater>
A slide type coater shown in FIG. 1 was prepared.

<Coating / Drying / Conveying>
Using the prepared photosensitive layer coating solution, surface protective layer coating solution and lowermost layer coating solution, using a strip support (using PET) 500 m having a thickness of 175 μm and a width of 1000 mm, the prepared slide type coater The strip-shaped support used by the application apparatus shown in FIG. 1 is used, and the degree of decompression in the decompression chamber at the coating head is changed as shown in Table 1 with respect to the degree of decompression during steady-state application. Further, the coating speed is 30 m / min, the coating width is 960 mm, the coating assisting coating solution is attached to the lowermost layer 5 g / m ² (wetting amount), and the photosensitive layer coating solution is attached to the intermediate layer 75 g / m ² ( The coating solution for the protective layer was applied to the upper layer so as to be 25 g / m ² (amount with wet), and after completion of drying, a rolled photothermographic material was prepared as Samples 101 to 109.

  The advance speed to the application position of the belt-like support on the backup roll of the slide type coater at the start of application is 2 mm / sec, and the distance from the belt-like support on the backup roll of the slide type coater at the start of application is It was performed at the time of application in a steady state and made into a sound. The decompression degree of the decompression chamber in the steady state was 350 Pa, and the distance from the application position of the belt-like support on the backup roll of the slide type coater was 250 μm. The viscosity of the coating solution for the photosensitive layer was 0.5 Pa · s, the viscosity of the coating solution for the surface protective layer was 1.0 Pa · s, and the viscosity of the coating solution for the lowermost layer was 0.02 Pa · s. The viscosity indicates a value measured with a B-type viscometer.

(Evaluation)
Table 1 shows the results of visual observation of the application state of the manufactured samples 101 to 109 at the start of application and evaluation according to the following evaluation rank.

Evaluation rank of the coating state at both ends ○: The coating liquid is uniformly applied to the entire width from the start of application and no occurrence of poor wetting is observed. Δ: The distance at which the coating liquid is uniformly applied to the entire width from the start of application is less than 1 m. X: Distance from which coating liquid is uniformly applied over the entire width from the start of coating exceeds 1 m

  The effectiveness of the present invention was confirmed.

Example 2
<Preparation of coating solution>
The photosensitive layer coating solution, the surface protective layer coating solution and the lowermost layer coating solution prepared in Example 1 were used.

<Preparation of slide type coater>
A slide type coater shown in FIG. 1 was prepared.

<Coating / Drying / Conveying>
The prepared coating liquid for the photosensitive layer, the coating liquid for the surface protective layer, and the coating liquid for the lowermost layer was prepared by using 500 m of a belt-like support (using PET) having a thickness of 175 μm and a width of 1000 mm. As shown in Table 2, the forward speed to the coating position of the belt-like support on the backup roll of the slide type coater at the start of coating is changed as shown in Table 2, and the belt-like shape held on the back roll by the coating device shown in FIG. The support is coated at a coating speed of 30 m / min, the coating width is 960 mm, the lowermost layer is coated with a coating-assisting coating solution 5 g / m ² (amount with wet), and the intermediate layer is coated with a coating solution for photosensitive layer 75 g / m. ² (wetting amount), the coating solution for the protective layer was applied to the upper layer so as to be 25 g / m ² (wetting amount), and after drying, a rolled photothermographic material was prepared and used as samples 201 to 208 .

  In addition, the decompression degree of the decompression chamber at the start of application is the same as the decompression degree in the steady state, and the distance from the application position of the belt-like support on the backup roll of the slide type coater at the start of application is the same as in the steady state application. The same as the interval. The decompression degree of the decompression chamber in the steady state was 350 Pa, and the distance from the application position of the belt-like support on the backup roll of the slide coater was 260 μm. The viscosity of the coating solution for the photosensitive layer was 0.5 Pa · s, the viscosity of the coating solution for the surface protective layer was 1.0 Pa · s, and the viscosity of the coating solution for the lowermost layer was 0.02 Pa · s. The viscosity indicates a value measured with a B-type viscometer.

(Evaluation)
Table 2 shows the results of visual observation of the applied state of the manufactured samples 201 to 208 at the start of application and evaluation according to the same evaluation rank as in Example 1.

  The effectiveness of the present invention was confirmed.

Example 3
<Preparation of coating solution>
The photosensitive layer coating solution, the surface protective layer coating solution and the lowermost layer coating solution prepared in Example 1 were used.

<Preparation of slide type coater>
A slide type coater shown in FIG. 1 was prepared.

<Coating / Drying / Conveying>
The prepared coating liquid for the photosensitive layer, the coating liquid for the surface protective layer, and the coating liquid for the lowermost layer was prepared by using 500 m of a belt-like support (using PET) having a thickness of 175 μm and a width of 1000 mm. When the coating is started, the distance between the slide-type coater and the belt-like support on the backup roll is changed as shown in Table 3 with respect to the gap in the steady state, and the coating apparatus shown in FIG. On the held belt-like support, the coating speed is 30 m / min, the coating width is 960 mm, the coating auxiliary coating solution is attached to the lowermost layer, 5 g / m ² (wetting amount), and the photosensitive layer coating solution is attached to the intermediate layer. the amount 75 g / m ² (wet with amount), was coated a protective layer coating solution for the upper layer such that 25 g / m ² (wet with weight), to prepare a take-up photothermographic material after completion of drying the sample 301 ~ 308 .

  In addition, the decompression degree of the decompression chamber at the start of coating was set to be the same as the decompression degree in the steady state, and the advance speed to the coating position of the belt-like support on the backup roll of the slide type coater was set to 2 mm / sec. The decompression degree of the decompression chamber in the steady state was 350 Pa, and the distance from the application position of the belt-like support on the backup roll of the slide coater in the steady state was 260 μm. The viscosity of the coating solution for the photosensitive layer was 0.5 Pa · s, the viscosity of the coating solution for the surface protective layer was 1.0 Pa · s, and the viscosity of the coating solution for the lowermost layer was 0.02 Pa · s. The viscosity indicates a value measured with a B-type viscometer.

(Evaluation)
Table 3 shows the results of visual observation of the coating state of the manufactured samples 301 to 308 at the start of coating and evaluation according to the same evaluation rank as in Example 1.

  The effectiveness of the present invention was confirmed.

It is the schematic of the slide application | coating system which forms and apply | coats a bead using a slide type | mold coater. It is the schematic diagram which showed the flow volume distribution of the high-viscosity coating liquid which flows down the slide surface of the slide type coater shown in FIG. It is an expansion schematic plan view of the part shown by S of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Slide type coater 101, 101a-100d Bar 102, 102a-102c Slit 103, 103a-103c Sliding surface 104 Coating width control plate 2 Back roll 3 Band-shaped support body 5 Bead 6 Decompression chamber W1 Coating point

Claims (9)

A backup roll for winding and guiding the belt-like support that is continuously conveyed;
A simultaneous multi-layer slide type coater that forms a bead on the belt-shaped support in the vicinity of the backup roll to form a bead;
In a coating method using a coating apparatus having a decompression chamber provided close to the outer peripheral surface of the backup roll on the upstream side of the bead,
The coating solution has at least two volatile solvent-containing coating solutions and a coating auxiliary coating solution,
An application method, wherein the application is performed with the degree of vacuum in the vacuum chamber at the top of application being 50 to 600 Pa higher than the degree of vacuum during steady-state application. A backup roll that guides and conveys the belt-like support that is continuously conveyed;
A simultaneous multi-layer slide type coater that forms a bead on the belt-like support in the vicinity of the backup roll to form a bead;
In a coating method using a coating apparatus having a decompression chamber provided close to the outer peripheral surface of the backup roll on the upstream side of the bead,
The coating solution has at least two volatile solvent-containing coating solutions and a coating auxiliary coating solution,
A coating method, characterized in that at the start of coating, the advance speed of the simultaneous multilayer slide type coater to the coating position of the belt-like support on the backup roll is set to 5 to 100 mm / sec. A backup roll that guides and conveys the belt-like support that is continuously conveyed;
A simultaneous multi-layer slide type coater that forms a bead on the belt-shaped support in the vicinity of the backup roll to form a bead;
In a coating method using a coating apparatus having a decompression chamber provided close to the outer peripheral surface of the backup roll on the upstream side of the bead,
The coating solution has at least two volatile solvent-containing coating solutions and a coating auxiliary coating solution,
A coating method, characterized in that an interval between the simultaneous multi-layer slide type coater at the start of coating and the belt-like support on the backup roll is made 50 to 150 μm narrower than a spacing at the time of steady-state coating. The decompression degree at the coating head of the decompression chamber is set to 50 to 300 Pa higher than the decompression degree at the time of steady-state application, and the interval between the simultaneous multi-layer slide type coater and the belt-like support on the backup roll is set in the steady-state application. The coating method according to claim 2, wherein the coating is made narrower by 50 to 150 μm than the time interval. The coating method according to claim 2 or 3, wherein the coating is performed with a degree of decompression at the top of coating in the decompression chamber being 50 to 300 Pa higher than the degree of decompression during steady-state coating. The coating method according to claim 3, wherein the simultaneous multi-layer slide type coater moves the advance speed at a rate of 10 to 100 mm / sec to the coating point of the belt-like support on the backup roll at the start of coating. The said coating liquid for coating assistance is discharged from the lowest slit, uses the same solvent as the adjacent coating liquid, and has a viscosity of 0.5 to 50 mPa · s. Application method. The coating method according to claim 1, wherein the coating liquid containing the volatile solvent has a viscosity of 0.2 to 2.0 Pa · s. The coating method according to any one of claims 1 to 8, wherein the coating solution containing the volatile solvent is a coating solution for a photothermographic material.

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