JP2008178848A - Multi-layer coating method, and planographic printing plate and manufacturing method thereof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide stable coating without coating defects such as poor coating, liquid repellency and coating streak when a non-contact coater is used as a coating device for the upper layer to conduct sequential multi-layer coating. <P>SOLUTION: A sequential multi-layer coating method comprises: applying a photosensitive layer protection layer (A) L1 with a rod coating device 14 onto a continuously traveling web 12; and applying a photosensitive layer protection layer (B) L2 with an extrusion coating device 16, wherein W/[U(γ1-γ2)]≥0.018...(A1) is satisfied when W (cc/square meter) represents a wet coating amount of the photosensitive layer protection layer (B) L2; U (m/min) represents a traveling speed of the web 12; γ1 (mN/m) represents a dynamic surface tension of the photosensitive layer protection layer (B) L2; and γ2 (mN/m) represents a static surface tension of the photosensitive layer protection layer (A) L1. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a multi-layer coating method, a lithographic printing plate and a method for producing the same, and more particularly, a multi-layer coating method in which a plurality of layers are coated on a continuously running belt-like web and a lithographic plate using the multi-layer coating method. The present invention relates to a printing plate manufacturing method and a planographic printing plate.

  For example, in the production of a lithographic printing plate, generally, one or both sides of a strip-shaped aluminum plate are grained according to a conventional method to produce a web which is a support for producing a lithographic printing plate, and the sand of this web is produced. There is a step of performing multi-layer coating in which a plurality of coating liquids are stacked on the web after applying a pretreatment such as an anodized film on the conspicuous surface (see, for example, Patent Document 1).

  As a coating solution for multi-layer coating, a photosensitive layer A (lower layer) is applied to a web, and the lower layer is in an undried state (wet state where the solid content concentration of the coating solution is 60% or less). When the upper layer) is applied in multiple layers, or when the photosensitive layer (lower layer) is applied and the photosensitive layer is in an undried state, the photosensitive layer protective layer (upper layer) is applied in multiple layers, or after the photosensitive layer is applied and dried, In some cases, the photosensitive layer protective layer A is applied, and the photosensitive layer protective layer B is applied while the photosensitive layer protective layer is undried.

  In addition, as a coating method in which a plurality of layers are applied in multiple layers, there are sequential multilayer coating and simultaneous multilayer coating. Sequential multi-layer coating is a method in which the lower layer and the upper layer are sequentially coated by different coating means, and the upper layer coating means is the tip of the lower layer and the coating means, such as an extrusion coater, a slide bead coater, a slad curtain coater, etc. It is common to use a non-contact type coating means in which a predetermined clearance is provided between the two and the tip of the coating means does not contact the lower layer (for example, Patent Document 1 and Patent Document 2).

  On the other hand, simultaneous multi-layer coating, like a slide bead coater or slide curtain coater, extrudes a plurality of coating liquids from a plurality of slits onto the slide surface and superimposes them on the slide surface. It is a method of applying to the web from the front end of the surface.

The above-described sequential multilayer coating and simultaneous multilayer coating are not limited to the production of lithographic printing plates, but are employed in production lines for various coated products having coating processes such as photographic photosensitive materials and magnetic recording media.
JP 2004-223456 A JP 59-189967 A

  However, as described above, when the multi-layer is sequentially applied by using a non-contact type application means as the upper layer application means, the upper layer is not well applied to the lower layer, the application failure or the liquid repelling, or the manufactured There is a problem that application defects such as formation of application stripes on the application surface of the lithographic printing plate may occur.

  On the other hand, as described above, even when simultaneous multilayer coating is performed with a slide bead coater or slide curtain coater, when the multilayer liquid in which the lower layer coating liquid and the upper layer coating liquid overlap flows down the slide surface, the flowing state of the multilayer liquid May become unstable, causing flow unevenness or liquid repellency on the slide surface, which may cause coating defects.

In addition, the coating defects that occur in the above-described sequential multi-layer coating and simultaneous multi-layer coating include high-speed coating with a web running speed of 60 m / min or more and thin film coating with a total coating amount of 50 cc / m ² or less in a wet state. It is easy to generate.

  The present invention has been made in view of such circumstances, and the first problem is that when a multi-layer is sequentially applied using a non-contact type coating coater as an upper layer coating means, poor coating is applied. It is an object of the present invention to provide a multilayer coating method capable of stable coating so as not to cause coating defects such as liquid repellency or coating stripes, a method for producing a lithographic printing plate using the multilayer coating method, and a lithographic printing plate To do.

  In addition, the second problem is that, when applying multiple layers simultaneously using a coating means having a slide surface, flow unevenness and liquid repellency are prevented from occurring on the slide surface. It is an object of the present invention to provide a multilayer coating method capable of preventing occurrence of defects, a method for producing a lithographic printing plate using the multilayer coating method, and a lithographic printing plate.

The inventor applied two layers by applying the upper layer on the continuously running web while the lower layer applied by the first application unit is in an undried state. Relationship between wet coating amount W and coating speed U in the case of sequential multi-layer coating for forming the above-mentioned multi-layers, in which multi-layers are sequentially coated using a non-contact type coating unit as the second coating unit. In the above, it was found that it is important to prevent coating defects by defining the liquid property values of the upper layer coating solution and the lower layer coating solution by the difference in surface tension and / or the difference in viscosity. In particular, it is important in the case of high-speed coating of 60 m / min or more, or in the case of thin-layer coating in which the total coating amount applied to the web is 50 cc / m ² or less in a wet state.

  Specifically, when the liquid property value of the coating solution is defined by surface tension, (i) the static surface tension of the lower layer, the dynamic surface tension of the upper layer, the wet coating amount of the upper layer, and the running speed of the web By controlling the four factors to a predetermined relationship, it is possible to remarkably suppress the occurrence of coating defects such as poor coating, repelling, and coating stripes. The important point here is that the surface tension of the upper layer needs to be defined by dynamic surface tension. This is because the surface tension (static surface tension) measured in the laboratory is small, but the surface tension (dynamic surface tension) when the interface between the lower layer and the upper layer is fluid and unstable as in actual coating. This is because a coating defect is more likely to occur as the liquid upper layer coating liquid becomes larger, and therefore, if the surface tension of the upper layer is defined by the static surface tension, the difference in surface tension between the lower layer and the upper layer cannot be correctly grasped.

  Further, when the viscosity of the coating solution is defined in addition to (i), (ii) the viscosity of the lower layer, the viscosity of the upper layer, the static surface tension of the lower layer, the dynamic surface tension of the upper layer, the wet coating amount of the upper layer, and It has been found that by controlling the six factors of the web traveling speed to a predetermined relationship, it is possible to remarkably suppress the occurrence of coating defects such as poor coating, repelling, and coating stripes.

  Therefore, by performing the multi-layer coating method of the present invention, it is possible to perform coating with good surface quality from the start of coating to the end of coating.

  In addition, the present inventor is not limited to the above-described sequential multilayer coating, but is a coating in which two or more layers are simultaneously multilayer coated on a continuously running web by a slide bead type or slide curtain type coating means having a slide surface. It has also been found that the method can prevent the occurrence of flow unevenness and liquid repellency on the slide surface by satisfying the relationship of the above four factors. The present invention has been made based on the above findings.

In order to achieve the above object, according to the first aspect of the present invention, while the lower layer applied by the first application unit is in an undried state on the continuously running web, the upper side is formed by the second application unit. Non-contact coating in which multiple layers of two or more layers are formed by applying the layers one after another, and the coating solution is applied as the second coating means in a non-contact state with the lower layer In the multi-layer coating method using a coating method, the wet coating amount of the upper layer is W (cc / m ² ), the running speed of the web is U (m / min), and the dynamic surface tension of the upper layer is Multilayers satisfying the relationship of the following formula (A1) when γ1 (mN / m) and the static surface tension of the lower layer in contact with the upper layer are γ2 (mN / m) Provide a coating method, W / [U (γ1-γ2)] ≧ 0.018 (A1).

  Claim 1 is the case of sequential multilayer coating, and the relationship of W / [U (γ1-γ2)] ≧ 0.018 (A1) is satisfied. It is possible to remarkably suppress the occurrence of coating defects such as repellency and repelling and coating stripes. Preferably, W / [U (γ1-γ2)] ≧ 0.02 is satisfied.

According to a second aspect of the present invention, in order to achieve the above-mentioned object, the upper layer is applied by the second application unit while the lower layer applied by the first application unit is in an undried state on the continuously running web. Non-contact coating in which multiple layers of two or more layers are formed by applying the layers one after another, and the coating solution is applied as the second coating means in a non-contact state with the lower layer In the multi-layer coating method using a coating method, the wet coating amount of the upper layer is W (cc / m ² ), the running speed of the web is U (m / min), and the dynamic surface tension of the upper layer is γ1 (mN / m), static surface tension of the lower layer in contact with the upper layer is γ2 (mN / m), liquid viscosity of the upper layer is μ1 (mPa · s), When the liquid viscosity of the lower layer in contact is μ2 (mPa · s), the following formulas (B1), (B2), and (B3 ) To satisfy the following relationship: W / [U (γ1-γ2)] ≧ 0.018 (B1), μ1> μ2 (B2), W (μ1-μ2) ) /U≧1.1 (B3).

  Claim 2 is the case of sequential multilayer coating, W / [U (γ1-γ2)] ≧ 0.018 (B1), μ1> μ2 (B2), W (μ1-μ2) / U ≧ 1. 1... (B3) is satisfied, so that it is possible to remarkably suppress the occurrence of single layer coating failure, liquid repellency, and coating defects such as coating stripes. Preferably, W / [U (γ1-γ2)] ≧ 0.02 and W (μ1-μ2) /U≧2.0 are satisfied.

According to the third aspect of the present invention, in order to achieve the above-mentioned object, two or more layers are simultaneously applied on a continuously running web by one application means of a slide bead method or a slide curtain method having a slide surface. In the coating method, the wet coating amount of the upper layer is W (cc / m ² ), the running speed of the web is U (m / min), and the dynamic surface tension of the upper layer is γ1 (mN / m). Providing a multilayer coating method characterized by satisfying the relationship of the following formula (A1) when the static surface tension of the lower layer in contact with the upper layer is γ2 (mN / m): W / [U (γ1-γ2)] ≧ 0.018 (A1).

  Claim 3 is the case of simultaneous multi-layer coating, and the relationship of W / [U (γ1-γ2)] ≧ 0.018 (A1) is satisfied, so that flow unevenness and liquid repelling occur on the slide surface. Etc. can be prevented, thereby preventing the occurrence of coating defects. Preferably, W / [U (γ1-γ2)] ≧ 0.02 is satisfied.

In order to achieve the above object, a fourth aspect of the present invention simultaneously coats two or more layers on a continuously running web by one application means of a slide bead system or slide curtain system having a slide surface. In the coating method, the wet coating amount of the upper layer is W (cc / m ² ), the running speed of the web is U (m / min), and the dynamic surface tension of the upper layer is γ1 (mN / m). The static surface tension of the lower layer in contact with the upper layer is γ2 (mN / m), the liquid viscosity of the upper layer is μ1 (mPa · s), and the lower layer in contact with the upper layer is Provided is a multilayer coating method characterized by satisfying the relationship of the following formulas (B1), (B2) and (B3) when the liquid viscosity is μ2 (mPa · s): W / [U (γ1 −γ2)] ≧ 0.018 (B1), μ1> μ2 (B2), W (μ1−μ2) /U≧1.1 (B3).

  Claim 4 is the case of simultaneous multilayer coating, W / [U (γ1-γ2)] ≧ 0.018 (B1), μ1> μ2 (B2), W (μ1-μ2) / U ≧ 1. 1... (B3) is satisfied, so that it is possible to prevent the occurrence of flow unevenness and liquid repellency on the slide surface, thereby preventing the occurrence of coating defects. Preferably, W / [U (γ1-γ2)] ≧ 0.02 and W (μ1-μ2) /U≧2.0 are satisfied.

  According to a fifth aspect of the present invention, in any one of the first to fourth aspects, the upper layer coating means is any one of extrusion coating, slide bead coating, and slide curtain coating.

  The fifth aspect of the present invention shows a preferred embodiment of the non-contact type coating means for coating the upper layer.

  A sixth aspect of the present invention is characterized in that, in any one of the first to fifth aspects, the traveling speed of the web is 60 m / min or more. This is because the present invention is particularly effective when the web traveling speed is 60 m / min or more.

A seventh aspect is characterized in that, in any one of the first to sixth aspects, the total coating amount applied to the web is 50 cc / m ² or less in a wet state. This is because the present invention is particularly effective in thin layer coating in which the total coating amount applied to the web is 50 cc / m ² or less in a wet state.

  According to an eighth aspect of the present invention, in order to achieve the above object, a lithographic printing plate is produced by using the multilayer coating method according to any one of the first to seventh aspects. A manufacturing method is provided. This is because by applying the multi-layer coating method of the present invention to the production of a lithographic printing plate, a lithographic printing plate having an excellent surface shape can be produced.

  According to a ninth aspect of the present invention, there is provided a planographic printing plate manufactured by the method of manufacturing a planographic printing plate according to the eighth aspect. Thereby, a lithographic printing plate having an excellent surface shape can be obtained.

  A lithographic printing plate according to a ninth aspect is characterized in that, in the lithographic printing plate of the ninth aspect, after the photosensitive layer is applied and dried, a photosensitive layer protective lower layer and a photosensitive layer protective upper layer, which are photosensitive layer protective layers, are applied in two layers. A tenth aspect of the present invention shows a preferred example of a lower layer and an upper layer formed using a multilayer coating method in a lithographic printing plate.

  An eleventh aspect of the present invention is the planographic printing plate of the tenth aspect, wherein the photosensitive layer protective layer coating solution is a pure aqueous solvent.

  According to the present invention, when a multi-layer is sequentially applied by using a non-contact type coating means as an upper layer coating means, it is stable so that coating defects such as poor coating, liquid repellency, and coating stripes do not occur. Can be applied.

  In addition, according to the present invention, when a plurality of layers are simultaneously applied by using one application means having a slide surface, it is possible to prevent application defects such as flow unevenness and liquid repellency on the slide surface.

  Moreover, if a lithographic printing plate is produced by the multilayer coating method of the present invention, a high-quality lithographic printing plate having an excellent surface shape can be obtained.

Hereinafter, a multilayer coating method according to the present invention, a method for producing a lithographic printing plate using the multilayer coating method, and a preferred embodiment of the lithographic printing plate will be described with reference to the drawings.
The multi-layer coating method of the present invention will be described as an example incorporated in the production of a lithographic printing plate, but the present invention is not limited to being incorporated in the production of a lithographic printing plate, and can be applied to various production lines for performing multi-layer coating. .

  In this embodiment, an example in which the photosensitive layer protective layer (A) L1 is applied as the lower layer and the photosensitive layer protective layer (B) L2 is applied as the upper layer will be described. However, the present invention is not limited to the upper and lower layers being a photosensitive layer protective layer. Moreover, it is not limited to two layers of a lower layer and an upper layer, What is necessary is just a multilayer coating of two or more layers. For example, in the case of three layers, the lowermost layer and the intermediate layer are in a relationship between the lower layer and the upper layer, and further, the intermediate layer and the uppermost layer are in a relationship between the lower layer and the upper layer. become.

(First embodiment)
In the first embodiment of the multilayer coating method of the present invention, a photosensitive layer protective layer (A) L1 (lower layer, hereinafter referred to as “lower layer”) is formed on a continuously running web by a rod coating device. While the photosensitive layer protective layer (A) L1 is in an undried state (wet state in which the solid content concentration of the coating solution is 60% or less), the photosensitive protective layer (B) L2 ( This is a case of sequential multilayer coating in which the upper layer (hereinafter referred to as “upper layer”) is applied in layers.

  FIG. 1 shows a coating line 10 which is an embodiment for carrying out the first embodiment of the multilayer coating method of the present invention. An aluminum web 12 that is a support for a lithographic printing plate runs on the coating line 10. The web 12 is subjected to pretreatment such as graining treatment and anodizing film treatment, and then the photosensitive layer is applied by rod coating or the like, dried by hot air drying or the like, and a photosensitive layer is formed on the aluminum support. ing.

  In this coating line 10, the web 12 continuously travels along a certain conveyance direction indicated by an arrow “a”, and the photosensitive layer protective layer (A) L <b> 1 (lower layer) is applied in order from the upstream side in the traveling direction. A rod coating device 14 for coating and an extrusion coating device 16 for coating the photosensitive layer protective layer (B) L2 (upper layer) are disposed.

  Here, as described above, the application means for applying the upper layer needs to be a non-contact application method in which the application liquid is applied in a non-contact state with the lower layer. In addition, for example, a slide bead coating device and a slide curtain coating device can be preferably used. On the other hand, the coating means for coating the lower layer is not limited to the non-contact coating method, but is a blade coater, air knife coater, roll coater, bar coater, gravure coater, rod blade coater, lip coater, curtain coater, die coater. In addition, various known coating apparatuses such as a slide bead can be used.

  Further, on the downstream side of the extrusion coating device 16, a drying device for drying the multilayer coating layer L3 in which the photosensitive layer protective layer (A) L1 (lower layer) and the photosensitive layer protective layer (B) L2 (upper layer) are multilayer coated. 18 is disposed. As the drying device 18, various drying devices such as a hot air drying type for drying the multilayer coating layer L3 with hot air, an infrared drying type for drying with infrared rays, and a condensation drying type in which a condenser plate is disposed in the vicinity of the multilayer coating layer L3 can be used. .

  Next, each component of the rod coating device 14 and the extrusion coating device 16 will be described in detail.

  As shown in FIG. 2, the rod coating device 14 mainly has a rod 14 </ b> A that rotates in the same direction (arrow b direction) as the traveling direction “a” of the web 12 while being in contact with the web 12, and a V-shape formed on the upper surface. Rod support member 14B for supporting the rod 14A by the groove of the mold, upstream dam plate 14C erected on the upstream side of the rod support member 14B, and downstream dam plate erected on the downstream side of the rod support member 14B 14D, rod support member 14B, upstream dam plate 14C, and base 14E to which downstream dam plate 14D is fixed.

  Between the rod support member 14B and the upstream side weir plate 14C, an upstream side liquid supply channel 14F for supplying the photosensitive layer protective layer (A) coating solution is provided on the upstream side of the rod 14A. Between the downstream weir plate 14D, a downstream liquid supply passage 14G for supplying the photosensitive layer protective layer (A) coating solution is provided on the downstream side of the rod 14A. The upstream liquid supply channel 14F and the downstream liquid supply channel 14G communicate with each other through a communication channel 14H provided at a lower portion of the rod support member 14B. A liquid supply line 14J for supplying the photosensitive layer protective layer (A) coating liquid is connected to the lower end of the upstream liquid supply flow path 14F.

  Above the web 12, a pair of web pressing rollers that press the web 12 against the rod 14A while being driven to rotate about the rotating shaft 14L when the photosensitive layer protective layer (A) coating solution is applied. 14K is provided. That is, the rotating shaft 14L of the web pressing roller 14K can be slid in the AB direction in FIG. 2 by a sliding means (not shown).

  As the rod 14A, a rolling rod in which grooves are engraved at a constant interval in the circumferential direction of the rod surface by rolling, a wire rod in which a wire is tightly wound on the rod surface, or the like can be suitably used.

  The outer diameter of the rod 14A is preferably in the range of φ1 to 30 mm, and in the range of φ6 to 20 mm from the viewpoint of accuracy (straightness / roundness), rotational moment, weight balance, etc. when rolling the rod. More preferably.

  The rod support member 14B is not limited as long as it can reliably support the rotating rod 14A, but a member having a low coefficient of friction with the rod 14A is preferable for smooth rotation of the rod 14A, and is further resistant to abrasion. Those having high wear resistance are preferred. Examples of satisfying these conditions include polyethylene resin, fluororesin, polyacetal resin, etc. Among them, polytetrafluoroethylene known under the name of Teflon (R) (trade name of DuPont, USA), A polyacetal resin known under the name of Delrin (trade name of DuPont, USA) is particularly suitable in terms of friction coefficient and strength (abrasion resistance). Furthermore, what added fillers, such as glass fiber, a graphite, molybdenum disulfide, to these plastic materials can also be used. Further, after the rod support member 14B is made of a metal material, the above-mentioned plastic material is coated or pasted on the surface (at least the portion that supports the rod 14A), and the coefficient of friction with the rod 14A is increased. It may be made smaller. Alternatively, a rod support member 14B can be used in which various metal materials are impregnated with the above plastic material (for example, aluminum is impregnated with polytetrafluoroethylene).

  FIG. 3 shows the configuration of the extrusion coating device 16.

  As shown in FIG. 3, the extrusion coating device 16 mainly includes a die coater 20 and a backup roller 22 that wraps and supports the traveling web 12. The die coater 20 includes a die coater main body 20A formed in a substantially rectangular parallelepiped block shape, and the die coater main body 20A has a tip portion 20B whose section protrudes toward the backup roller 22 in a wedge shape. A tip surface 20C parallel to the direction of the rotation shaft 22A of the backup roller 22 is formed at the tip of the tip portion 20B. A clearance (gap) of about 0.1 to 1 mm is usually formed between the front end surface 20 </ b> C and the web 12 wound around the backup roller 22. The coating liquid discharged from the slit, which will be described later, to the front end surface 20C forms a bead 20M (liquid reservoir) of the coating liquid between the web 12 and the front end surface 20C, that is, the clearance, and the web is passed through the bead 20M. 12 is applied. Thereby, the extrusion coating device 16 applies the photosensitive layer protective layer (B) L2 (upper layer) in a non-contact state to the photosensitive layer protective layer (A) L1 (lower layer) already applied by the rod coating device 14. can do.

  Inside the die coater body 20A, a slit 20D, which is a narrow flow path through which the photosensitive layer protective layer (B) coating solution is discharged, is formed. The slit 20D is elongated along the width direction of the web 12, and the lower end of the slit 20D communicates with the liquid supply flow path 20F via the manifold 20E. Thereby, the photosensitive layer protective layer (B) coating solution supplied from the liquid supply channel 20F is spread in the width direction of the web 12 in the manifold 20E, flows through the slit 20D, and is discharged from the tip surface 20C.

  Further, a decompression chamber 20G is provided below the tip portion 20B of the die coater body 20A, and a decompression space 20N is provided in a portion surrounded by the tip portion 20B of the die coater body 20A, the backup roller 22, and the decompression chamber 20G. It is formed.

  A decompression tube 20H for decompressing the inside of the decompression chamber 20G is connected to the side surface of the decompression chamber 20G. Thereby, the upstream side of the bead 20M described above is depressurized by depressurizing the decompression space 20N, and the bead 20M can be stably formed.

Inside the decompression chamber 20G, a bowl-shaped surplus liquid receiver 20J that receives an excess of the photosensitive layer protective layer (B) coating liquid discharged from the slit 20D that has not been applied to the web 12 is provided. The receptacle 20J is connected to the storage tank 20L via the drain pipe 20K.
Next, the multilayer coating method of the present invention will be described using the above-described coating line 10 of FIG.

  First, a photosensitive layer is applied to a surface of the web 12 which has been pretreated such as graining and anodized film using a rod coating device or the like, and dried using a hot air drying method or the like. Subsequently, a photosensitive layer protective layer (A) coating solution is applied by the rod coating device 14 onto the coating film surface on which the photosensitive layer has been applied and dried. That is, the web 12 already coated with the photosensitive layer is brought into contact with the rod 14A, and the coating solution for the photosensitive layer protective layer (A) is supplied to the upstream liquid supply channel 14F and the downstream liquid supply channel 14G. To do. As a result, a first liquid pool 14M of the coating liquid is formed on the upstream side where the web 12 and the rod 14A contact each other, and a second liquid pool 14N is formed on the downstream side. Then, the rotating rod 14B draws the photosensitive layer protective layer (A) coating solution from these liquid reservoirs 14M and 14N and transfers it to the web 12, whereby the photosensitive layer protective layer (A) coating solution is applied to the web 12 in a predetermined manner. It is applied by thickness. As a result, the photosensitive layer protective layer (A) L1 as the lower layer is formed on the web 12.

  Next, the web 12 on which the photosensitive layer protective layer (A) L1 is formed travels to the extrusion coating apparatus 16 while the photosensitive layer protective layer (A) L1 is in an undried state, and the photosensitive layer protective layer (A ) A photosensitive layer protective layer (B) L2 is applied on top of L1. That is, the photosensitive layer protective layer (B) coating solution is discharged from the slit 20D of the die coater body 20A, and the inside of the decompression chamber 20G is decompressed to a range of 50 to 1000 Pa · s. As a result, a bead 20M is formed between the tip surface 20C of the die coater body 20A and the photosensitive layer protective layer (A) L1 applied to the web 12, and the photosensitive layer is in an undried state via the bead 20M. A photosensitive layer protective layer (B) L2 is applied on the protective layer (A) L1 (so-called WET ON WET coating is performed). The multilayer coating layer L3 in which the photosensitive layer protective layer (A) L1 and the photosensitive layer protective layer (B) L2 are successively coated is dried by the drying device 18 and then wound around a winding device (not shown). Thereby, a planographic printing plate is manufactured.

  In this sequential multilayer coating, coating is performed so as to satisfy either of the following [A] and [B].

[A] The wet coating amount of the photosensitive layer protective layer (B) L2 (upper layer) is W (cc / m ² ), the running speed of the web 12 is U (m / min), and the photosensitive layer protective layer (B) L2 (upper layer) ) Is the dynamic surface tension of γ1 (mN / m), and the static surface tension of the photosensitive layer protective layer (A) L1 (lower layer) is γ2 (mN / m). Satisfied.

W / [U (γ1-γ2)] ≧ 0.018 (preferably 0.02) (A1)
[B] Photosensitive layer protective layer (B) The wet coating amount of L2 (upper layer) is W (cc / m ² ), the traveling speed of the web 12 is U (m / min), and the photosensitive layer protective layer (B) L2 (upper layer) ) Dynamic surface tension of γ1 (mN / m), photosensitive layer protective layer (A) L1 (lower layer) static surface tension of γ2 (mN / m), photosensitive layer protective layer (B) L2 (upper layer) When the liquid viscosity is μ1 (mPa · s) and the liquid viscosity of the protective layer (A) L1 (lower layer) is μ2 (mPa · s), the following formulas (B1), (B2), and (B3) Satisfy the relationship.

W / [U (γ1-γ2)] ≧ 0.018 (preferably 0.02) (B1)
μ1> μ2 (B2)
W (μ1-μ2) /U≧1.1 (preferably 2.0) (B3)
Thus, in the successive multilayer coating, the photosensitive layer protective layer (B) L2 is applied to the photosensitive layer protective layer (A) L1 by coating so as to satisfy any of the above [A] and [B]. Application failure that is difficult to stick, liquid repelling that the photosensitive layer protective layer (B) L2 is repelled by the photosensitive layer protective layer (A) L1, or coating stripes on the surface of the manufactured lithographic printing plate It is possible to apply stably so that application defects such as

(Second Embodiment)
In the second embodiment of the multi-layer coating method of the present invention, the photosensitive layer protective layer (A) L1 (lower layer) and the photosensitive layer protective layer are formed on a continuously running web 12 by one slide bead coating device having a slide surface. (B) When L2 (upper layer) is applied simultaneously. The same members and devices as those in the first embodiment will be described with the same reference numerals.

  FIG. 4 shows a coating line 30 which is an embodiment for carrying out the second embodiment of the multilayer coating method of the present invention. A web 12 that is a support for a lithographic printing plate runs on the coating line 30. The web 12 is subjected to pretreatment such as graining treatment and anodizing film treatment, and then the photosensitive layer is applied by rod coating or the like, dried by hot air drying or the like, and a photosensitive layer is formed on the aluminum support. ing.

  In this coating line 30, the web 12 continuously travels along a certain conveying direction indicated by an arrow “a”, and the photosensitive layer protective layer (A) L 1 (lower layer) and the photosensitive layer protective layer are provided along the traveling path. (B) A slide bead coating device 32 that simultaneously coats L2 (upper layer) is provided. As a coating means having a slide surface, a known slide curtain coating device can be used in addition to the slide bead coating device. Further, the drying device 18 provided at the downstream position of the slide bead coating device 32 is the same as that of the first embodiment, and the description thereof is omitted.

  As shown in FIGS. 5 and 6, the slide bead coating device 32 mainly includes a slide hopper main body 34 and a backup roller 36 that wraps and supports the web 12. The photosensitive layer protective layer (A) coating solution and the photosensitive layer protective layer (B) coating solution applied to the web 12 are supplied from the coating solution tank (not shown) through the supply lines 38 and 40, respectively, in the slide hopper body 34. It is supplied to the manifolds 42 and 44. The slide hopper main body 34 is mainly composed of a plurality of die blocks 46, 46... And a pair of side plates 48 (see FIG. 6) applied to the side surfaces of the die blocks 46 in a combined state. Inside each of the coating liquids L1 ′ and L2 ′ comprising the supply pipes 38 and 40, the manifolds 42 and 44, the slits 50 and 52, and the slide surface 54 (photosensitive layer protective layer (A) coating liquid and photosensitive layer protective layer (B ) A path through which the coating liquid) flows is formed. The coating liquids L1 ′ and L2 ′ supplied to the manifolds 42 and 44 are spread in the coating width direction and then pushed out through the slits 50 and 52 to the slide surface 54 inclined downward on the upper surface of the slide hopper body 34. . The coating liquids L <b> 1 ′ and L <b> 2 ′ pushed out onto the slide surface 54 are not mixed with each other, become a multilayer liquid L <b> 3 ′, flow down the slide surface 54, and reach the lip tip 58 at the lower end of the slide surface 54. The multilayer liquid L3 ′ that has reached the lip tip 58 forms a bead 62 (liquid pool) of the multilayer liquid L3 ′ in the clearance (gap) 60 between the lip tip 58 and the web 12 that is wound around the backup roller 36 and travels. Then, it is applied to the web 12 through the bead 62. Thus, a multilayer L3 is formed in which the photosensitive layer protective layer (A) L1 (lower layer) and the photosensitive layer protective layer (B) L2 (upper layer) are simultaneously coated.

Further, a decompression chamber 66 is provided below the lip tip 58 of the slide hopper body 34, and a decompression space 68 is formed in a portion surrounded by the slide hopper body 34, the backup roller 36, and the decompression chamber 66. An exhaust pipe 70 connected to a vacuum device (not shown) is connected to the side surface of the decompression chamber 66, and a drain pipe 72 for discharging the multilayer liquid L 3 ′ falling inside the decompression chamber 66 is connected to the bottom surface. The The decompression chamber 66 stabilizes the bead 62 by setting the upstream side (lower side in FIG. 5) of the bead 62 to a negative pressure. The decompression space 68 inside the decompression chamber 66 is preferably decompressed in the range of 50 to 1000 Pa · s.
Also in the case of the simultaneous multilayer coating in the second embodiment, the coating is performed so as to satisfy any of the following [A] and [B].

[A] The wet coating amount of the photosensitive layer protective layer (B) L2 (upper layer) is W (cc / m ² ), the running speed of the web 12 is U (m / min), and the photosensitive layer protective layer (B) L2 (upper layer) ) Is the dynamic surface tension of γ1 (mN / m), and the static surface tension of the photosensitive layer protective layer (A) L1 (lower layer) is γ2 (mN / m). Satisfied.

W / [U (γ1-γ2)] ≧ 0.018 (preferably 0.02) (A1)
[B] Photosensitive layer protective layer (B) The wet coating amount of L2 (upper layer) is W (cc / m ² ), the traveling speed of the web 12 is U (m / min), and the photosensitive layer protective layer (B) L2 (upper layer) ) Dynamic surface tension of γ1 (mN / m), photosensitive layer protective layer (A) L1 (lower layer) static surface tension of γ2 (mN / m), photosensitive complementary misfeed (B) L2 (upper layer) When the liquid viscosity is μ1 (mPa · s) and the liquid viscosity of the protective layer (A) L1 (lower layer) is μ2 (mPa · s), the following formulas (C1), (C2), and (C3) Satisfy the relationship.

W / [U (γ1-γ2)] ≧ 0.018 (preferably 0.02) (B1)
μ1> μ2 (B2)
W (μ1-μ2) /U≧1.1 (preferably 2.0) (B3)
Thus, in simultaneous multi-layer coating, by applying so as to satisfy any of the above [A] and [B], when a multi-layer is simultaneously coated using a coating coater having a slide surface It is possible to prevent application defects such as flow unevenness and liquid repellency on the slide surface.

  The web 12 used in the present invention may be in the form of a strip or a sheet, and may be a sheet metal such as aluminum (aluminum web 12 described above), paper, plastic film, resin-coated paper, synthetic paper, etc. Can be used. When an aluminum plate is used as the web 12, for example, JIS1050 material, JIS1100 material, JIS1070 material, Al-Mg alloy, Al-Mn alloy, Al-Mn-Mg alloy, Al-Zr alloy, Al -An Mg-Si alloy or the like can be applied. Materials for plastic films include polyolefins such as polyethylene and polypropylene, vinyl polymers such as polyvinyl acetate, polyvinyl chloride and polystyrene, polyamides such as 6,6-nylon and 6-nylon, polyethylene terephthalate, polyethylene-2 Polyester such as 1,6-naphthalate, polycarbonate, cellulose acetate such as cellulose triacetate, and the like. The resin used for the resin-coated paper is typically polyolefin such as polyethylene, but is not limited thereto.

  The thickness of the web 12 is not particularly limited, but a thickness of about 0.01 mm to 1.0 mm is advantageous in terms of handling and versatility.

  Further, as the photosensitive layer coating solution that is applied and dried in advance on the web 12, for example, an aqueous solution of a polymer compound, an organic solvent solution, a pigment dispersion, a colloidal solution, or the like can be used. Examples of the photosensitive layer coating solution for constituting the photosensitive layer of the lithographic printing plate include those that constitute the photosensitive layers of the following aspects (1) to (11).

  (1) An embodiment in which the photosensitive layer contains an infrared absorber, a compound that generates an acid by heat, and a compound that crosslinks by an acid.

  (2) An embodiment in which the photosensitive layer contains an infrared absorber and a compound that becomes alkali-soluble by heat.

  (3) An embodiment in which the photosensitive layer includes two layers, a layer containing a compound that generates radicals upon irradiation with laser light, an alkali-soluble binder, and a polyfunctional monomer or prepolymer, and an oxygen blocking layer.

  (4) An embodiment in which the photosensitive layer is composed of two layers of a physical development nucleus layer and a silver halide emulsion layer.

  (5) A mode in which the photosensitive layer includes three layers of a polymerization layer containing a polyfunctional monomer and a polyfunctional binder, a layer containing silver halide and a reducing agent, and an oxygen blocking layer.

  (6) A mode in which the photosensitive layer includes two layers of a layer containing a novolac resin and naphthoquinone diazide and a layer containing silver halide.

  (7) A mode in which the photosensitive layer contains an organic photoconductor.

  (8) A mode in which the photosensitive layer includes 2 to 3 layers including a laser light absorbing layer to be removed by laser light irradiation, and a lipophilic layer and / or a hydrophilic layer.

  (9) A compound in which the photosensitive layer absorbs energy to generate an acid, a polymer compound having a functional group that generates sulfonic acid or carboxylic acid by an acid in the side chain, and an acid generator by absorbing visible light The aspect containing the compound which gives energy to.

  (10) The mode in which the photosensitive layer contains a quinonediazide compound and a novolac resin.

  (11) A mode in which the photosensitive layer contains a compound that decomposes by light or ultraviolet rays to form a crosslinked structure with itself or other molecules in the layer and an alkali-soluble binder.

  Next, examples in which a lithographic printing plate is produced using the coating line 10 described in the first embodiment of the present invention will be described, but of course the present invention is not limited thereto.

1. Production of Support (Web 12) A support that has been subjected to the following surface treatment using a JIS A 1050 aluminum strip having a thickness of 0.30 mm and a width of 1030 mm, and has been subjected to surface treatment and photosensitive layer coating and drying. (Web 12) was obtained.

<Surface treatment>
In the surface treatment, the following various treatments (a) to (f) were continuously performed. In addition, after each process and water washing, the liquid was drained with the nip roller.

(A) The aluminum plate was etched with an aqueous solution having a caustic soda concentration of 26 mass%, an aluminum ion concentration of 6.5 mass%, and a temperature of 70 ° C. to dissolve the aluminum plate at 5 g / m ² , and then washed with water.

  (B) A desmut treatment by spraying was performed with a 1% by mass aqueous solution of nitric acid having a temperature of 30 ° C. (including 0.5% by mass of aluminum ions), and then washed with water.

(C) An electrochemical surface roughening treatment was continuously performed using an alternating voltage of 60 Hz. The electrolytic solution at this time was a 1% by mass aqueous nitric acid solution (including 0.5% by mass aluminum ions and 0.007% by mass ammonium ions) at a temperature of 30 ° C. The AC power source was subjected to an electrochemical surface roughening treatment using a carbon electrode as a counter electrode using a trapezoidal rectangular wave alternating current with a time TP of 2 msec until the current value reached a peak from zero and a duty ratio of 1: 1. Ferrite was used for the auxiliary anode. The current density was 25 A / dm ² at the current peak value, and the amount of electricity was 250 C / cm ² in terms of the total amount of electricity when the aluminum plate was the anode. 5% of the current flowing from the power source was shunted to the auxiliary anode. Thereafter, it was washed with water.

(D) An etching process by spraying is performed at 35 ° C. with an aqueous solution having a caustic soda concentration of 26 mass% and an aluminum ion concentration of 6.5 mass% to dissolve the aluminum plate by 0.2 g / m ² , and electrochemical using the previous AC The smut component mainly composed of aluminum hydroxide generated during roughening was removed, and the edge portion of the generated pit was dissolved to smooth the edge portion. Thereafter, it was washed with water.

  (E) A desmut treatment by spraying was performed with a 25% by weight aqueous solution of sulfuric acid having a temperature of 60 ° C. (containing 0.5% by weight of aluminum ions), followed by washing with water by spraying.

(F) Anodization was performed for 50 seconds at a temperature of 33 ° C. and a current density of 5 (A / dm ² ) in an aqueous solution having a sulfuric acid concentration of 170 g / liter (containing 0.5 mass% of aluminum ions). Thereafter, it was washed with water. At this time, the weight of the anodized film was 2.7 g / m ² .

  The surface roughness Ra of the aluminum support thus obtained was 0.27 (measuring instrument: Surfcom manufactured by Tokyo Seimitsu Co., Ltd., stylus tip diameter 2 micrometer).

<Back coat layer>
Next, the following undercoat layer coating solution was applied to the back surface of the aluminum support with a wire bar and dried at 100 ° C. for 10 seconds. The coating amount was 0.5 g / m ² .
(Coating solution for back coat layer)
・ PR55422 (Sumitomo Bakelite Co., Ltd. 0.44g
(Phenol / m-cresol / p-cresol = 5/3/2 Average molecular weight 5300)
・ Fluorine surfactant 0.002g
(Megafuck F-780-F Dainippon Ink and Chemicals,
Methyl isobutyl ketone (MIBK) 30% by mass solution)
・ Methanol 3.70 g
・ 0.92 g of 1-methoxy-2-propanol
<Undercoat layer>
Next, the following undercoat layer coating solution was applied to the surface of the aluminum support with a wire bar and dried at 100 ° C. for 10 seconds. The coating amount was 10 mg / m ² .

(Coating solution for undercoat layer)
-High molecular compound of the following structure [Chemical Formula 1] (weight average molecular weight: 10,000) 0.05 g

・ Methanol 27g
・ Ion exchange water 3g
<Photosensitive layer>
On this, a high-sensitivity photopolymerizable composition P-1 having the following composition was coated with a rod coating device or the like so that the dry coating mass was 1.4 g / m ^2, and dried with hot air at 125 ° C. for 34 seconds, and photosensitive. A layer was formed.

(Photopolymerizable composition P-1)
・ Infrared absorber ([Chemical formula 2]) 0.038 g
-Polymerization initiator A ([Chemical formula 3]) 0.061 g
-Polymerization initiator B ([Chemical formula 5]) 0.094 g
・ Mercapto compound ([E1 to E4 of Chemical Formula 4]) 0.015 g
Polymerizable compound ([Chemical formula 6]) 0.425 g
-Binder polymer A ([Chemical formula 7]) 0.311 g
-Binder polymer B ([Chemical formula 8]) 0.250 g
・ Binder polymer C ([Chemical formula 9]) 0.062 g
・ Additive ([Chemical Formula 10]) 0.079 g
・ Polymerization inhibitor ([Chemical Formula 11]) 0.0012 g
Ethyl violet ([Chemical Formula 12]) 0.021 g
・ Fluorine surfactant 0.0081g
(Megafuck F-780-F Dainippon Ink and Chemicals,
Methyl isobutyl ketone (MIBK) 30% by mass solution)
・ Methyl ethyl ketone 5.886g
・ Methanol 2.733g
・ 1-methoxy-2-propanol 5.886 g

2. Coating of photosensitive layer protective layer (A) L1 (lower layer) and photosensitive layer protective layer (B) L2 (upper layer) The photosensitive layer protective layer (A1) L1 is applied to the web 12 obtained in 1 above using a rod coating device 14. (Lower layer) is applied, and while the photosensitive layer protective layer (A) L1 is in an undried state, the photosensitive layer protective layer (B) L2 (upper layer) is successively overlaid using the non-contact coating type extrusion coating apparatus 16. Applied. Next, the multilayer coating layer L3 on which the photosensitive layer protective layer (A) L1 and the photosensitive layer protective layer (B) L2 were multilayer coated was dried with the drying device 18, thereby producing a lithographic printing plate.

<Photosensitive layer protective layer (A) lower layer (L1)>
Synthetic mica (Somasif MEB-3L, 3.2% aqueous dispersion, manufactured by Coop Chemical Co., Ltd.), polyvinyl alcohol (Goselan CKS-50: saponification degree 99 mol%, polymerization degree 300, sulfonic acid modified polyvinyl alcohol A mixed aqueous solution (coating solution for protective layer) of surfactant A (manufactured by Nippon Emulsion Co., Ltd., Emalex 710) and surfactant B (Adeka Pluronic P-84: manufactured by Asahi Denka Kogyo Co., Ltd.) The rod coating device 14 was applied so that the wet coating amount W of the coating solution was 15 (cc / m ² ).

The content ratio of synthetic mica (solid content) / polyvinyl alcohol / surfactant A / surfactant B in the mixed aqueous solution (coating liquid for protective layer) was 7.5 / 89/2 / 1.5 (mass). The coating amount (the coating amount after drying) was 0.5 g / m ² .

<Photosensitive layer protective layer (B) upper layer (L2)>
While the photosensitive layer protective layer (A) is in an undried state (wet state), on the surface of the photosensitive layer protective layer (A), an organic filler (Art Pearl J-7P, manufactured by Negami Industrial Co., Ltd.), synthesis Mica (Somasif MEB-3L, 3.2% aqueous dispersion, manufactured by Coop Chemical Co., Ltd.), polyvinyl alcohol (L-3266: degree of saponification 87 mol%, degree of polymerization 300, sulfonic acid-modified polyvinyl alcohol Nippon Synthetic Chemical Industry Co., Ltd.), thickener (Serogen FS-B, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.), polymer compound A, and surfactant (Nihon Emulsion Co., Emalex 710) mixed aqueous solution (for protective layer) The coating solution was applied with the extrusion coating device 16 so that the wet coating amount of the photosensitive layer protective layer (B) was 35 (cc / m ² ). At this time, the clearance between the tip surface 20C of the die coater main body 20A and the surface of the photosensitive layer protective layer (A) L1 applied to the web 12 is 0.25 mm, and the degree of vacuum in the vacuum chamber is 200 Ps · s. did.

The content ratio of the organic filler / synthetic mica (solid content) / polyvinyl alcohol / thickener / polymer compound A / surfactant in this mixed aqueous solution (protective layer coating solution) is 4.7 / 2.8. /67.4/18.6/2.3/4.2 (mass%), and the coating amount (the coating amount after drying) was 1.2 g / m ² .

<Drying of photosensitive layer protective layer (A / B)>
The multilayer coating layer L3 in which the photosensitive layer protective layer (A) L1 and the photosensitive layer protective layer (B) L2 are multilayer-coated is dried and dried with a hot air drying device 18 at a temperature of 125 ° C. and a wind speed of 7.0 m / sec for about 20 seconds. .

  When the coating speed (line speed) is increased to three stages of 60, 80 and 120 (m / min), W / [U (γ1-γ2)] ≧ 0.018 (preferably 0) of the present invention. 0.02) ... It was tested how the surface state of the produced lithographic printing plate differs depending on whether the relationship of the formula (A1) is satisfied or not. The surface evaluation is as follows.

○ = Repel, application streaks, uneven application, poor application, long time (30 minutes or more) not generated △ = Apply, but over time, liquid repel, liquid film breakage, application streaks, and uneven application occur × = Repel, Coating streaks, coating unevenness, and poor coating occurred. The dynamic surface tension of the coating solution is BP-D3 type manufactured by Kyowa Interface Science Co., Ltd. The static surface tension is CBVP manufactured by Kyowa Interface Science Co., Ltd. Measurement was performed in an environment at room temperature of 25 ° C. using a −Z type.

  The result is shown in FIG. The numerical value of the item “formula (A1)” in FIG. 7 is a value calculated by substituting the necessary numerical values into the formula (A1).

  As shown in FIG. 7, for test Nos. 4, 11, 14, and 15 where the calculated value of the formula (A1) does not satisfy 0.018 or more, the surface shape of the produced lithographic printing plate is x, and the lithographic plate The product quality of the printing plate was rejected.

  On the other hand, for Test Nos. 1-3, 5-10, and 12-13 satisfying the calculated value of the formula (A1) of 0.018 or more, the surface state of the produced lithographic printing plate is Δ˜ ○. The product quality of the planographic printing plate was acceptable. In particular, Test Nos. 2, 3, 6 to 10, and 12, 13 satisfying the calculated value of the formula (A1) of 0.02 or more were all “good” and good surface conditions.

  The lithographic printing plate production method, rod coating device, extrusion coating device conditions, the composition of the photosensitive layer L1, the antioxidant layer L2, and the evaluation criteria of the surface state of the produced lithographic printing plate are the same as in Example 1. is there.

When the coating speed (line speed) is increased to three stages of 60, 80, 120 (m / min), W / [U (γ1-γ2)] ≧ 0.018 (preferably 0) of the present invention. .02) ... (B1)
μ1> μ2 (B2)
W (μ1−μ2) /U≧1.1 (preferably 2.0)... (B3) How the surface state of the produced lithographic printing plate is satisfied or not satisfied Tested for differences. The viscosity of the coating solution was measured at room temperature (25 ° C.) using a B-type viscometer.

  The result is shown in FIG. The numerical values of the items “Expression (B1)”, “Expression (B2)”, and “Expression (B3)” in FIG. 8 are substituted by the numerical values necessary for Expression (B1), Expression (B2), and Expression (B3). It is a calculated value. In the formula (B2), “Y” is a case where the formula (B2) is satisfied, and “N” is a case where the formula (B2) is not satisfied.

  As shown in FIG. 8, test Nos. 16, 17, 21, 22, 24, 28, 29, 30, 31, and 34 that do not satisfy the formula (B1), the formula (B2), and the formula (B3) are evaluated as planar. X to Δ, and a high-quality lithographic printing plate could not be obtained.

  On the other hand, test Nos. 18, 19, 20, 23, 25, 26, 27, 32, and 33 satisfying the expressions (B1), (B2), and (B3) have a surface evaluation of “◯”. A high quality lithographic printing plate was obtained.

The block diagram of the coating line incorporating the sequential multilayer coating method of the 1st Embodiment of this invention Explanatory drawing explaining the rod coating device used as 1st application means in 1st Embodiment. Explanatory drawing explaining the extrusion coating device used as a 2nd coating means in 1st Embodiment. The block diagram of the coating line incorporating the simultaneous multilayer coating method of the 2nd Embodiment of this invention Side surface sectional view explaining the slide bead coating device used in the second embodiment The top view explaining the slide bead coating device used in the second embodiment FIG. 2 is an example of the first embodiment of the present invention, and is a table when the surface properties are defined as the liquid physical properties of the upper layer and lower layer coating liquids FIG. 4 is an example of the first embodiment of the present invention, and is a table when the viscosity is defined as the liquid physical properties of the upper layer and lower layer coating liquids.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Sequential multilayer coating application line, 12 ... Web, 14 ... Rod coating device, 16 ... Extrusion coating device, 18 ... Drying device, 20 ... Die coater, 22 ... Backup roller, 30 ... Simultaneous multilayer coating coating line, 32 ... Slide bead coating device, 34 ... Slide hopper body, 36 ... Backup roller, 38, 40 ... Supply line, 42, 44 ... Manifold, 46 ... Diglock, 48 ... Side plate, 50, 52 ... Slit, 54 ... Slide surface, 56 ... Layered liquid, 58 ... Lip tip, 60 ... Clearance, 62 ... Bead, 68 ... Vacuum chamber

Claims (11)

On the continuously running web, the lower layer applied by the first application means is in an undried state, and the upper layer is applied by overlapping the second layer by the second application means, thereby forming two or more layers. In a multilayer coating method using a non-contact coating method in which a coating liquid is applied in a non-contact state with the lower layer as the second coating means, which is a sequential multilayer coating to be formed.
The wet coating amount of the upper layer is W (cc / m ² ), the running speed of the web is U (m / min), the dynamic surface tension of the upper layer is γ1 (mN / m), A multilayer coating method characterized by satisfying the relationship of the following formula (A1) when the static surface tension of the lower layer in contact with the layer is γ2 (mN / m).
W / [U (γ1-γ2)] ≧ 0.018 (A1) On the continuously running web, the lower layer applied by the first application means is in an undried state, and the upper layer is applied by overlapping the second layer by the second application means, thereby forming two or more layers. In a multilayer coating method using a non-contact coating method in which a coating liquid is applied in a non-contact state with the lower layer as the second coating means, which is a sequential multilayer coating to be formed.
The wet coating amount of the upper layer is W (cc / m ² ), the running speed of the web is U (m / min), the dynamic surface tension of the upper layer is γ1 (mN / m), The static surface tension of the lower layer in contact with the layer is γ2 (mN / m), the liquid viscosity of the upper layer is μ1 (mPa · s), and the liquid viscosity of the lower layer in contact with the upper layer is μ2. A multilayer coating method characterized by satisfying the relationships of the following formulas (B1), (B2), and (B3) when (mPa · s).
W / [U (γ1-γ2)] ≧ 0.018 (B1)
μ1> μ2 (B2)
W (μ1-μ2) /U≧1.1 (B3) In a coating method in which two or more layers are simultaneously coated on a continuously running web by one coating means of a slide bead method or a slide curtain method having a slide surface,
The wet coating amount of the upper layer is W (cc / m ² ), the running speed of the web is U (m / min), the dynamic surface tension of the upper layer is γ1 (mN / m), A multilayer coating method characterized by satisfying the relationship of the following formula (A1) when the static surface tension of the lower layer in contact with the layer is γ2 (mN / m).
W / [U (γ1-γ2)] ≧ 0.018 (A1) In a coating method in which two or more layers are simultaneously coated on a continuously running web by one coating means of a slide bead method or a slide curtain method having a slide surface,
The wet coating amount of the upper layer is W (cc / m ² ), the running speed of the web is U (m / min), the dynamic surface tension of the upper layer is γ1 (mN / m), The static surface tension of the lower layer in contact with the layer is γ2 (mN / m), the liquid viscosity of the upper layer is μ1 (mPa · s), and the liquid viscosity of the lower layer in contact with the upper layer is μ2. A multilayer coating method characterized by satisfying the relationships of the following formulas (B1), (B2), and (B3) when (mPa · s).
W / [U (γ1-γ2)] ≧ 0.018 (B1)
μ1> μ2 (B2)
W (μ1-μ2) /U≧1.1 (B3)   The multilayer coating method according to any one of claims 1 and 2, wherein the second coating means is any one of extrusion coating, slide bead coating, and slide curtain coating.   The multi-layer coating method according to any one of claims 1 to 5, wherein a running speed of the web is 60 m / min or more. The multilayer coating method according to any one of claims 1 to 6, wherein the total coating amount of the multilayers applied to the web is 50 cc / m ² or less in a wet state.   A method for producing a lithographic printing plate, comprising producing a lithographic printing plate using the multilayer coating method according to any one of claims 1 to 7.   A lithographic printing plate produced by the method of producing a lithographic printing plate according to claim 8.   The lithographic printing plate according to claim 9, wherein both the upper layer and the lower layer are photosensitive layer protective layers.   11. The lithographic printing plate according to claim 10, wherein the photosensitive layer protective layer coating solution is an aqueous coating solution in which the solvent is pure water.