JP6586301B2 - Gravure coating equipment - Google Patents

Description

  The present invention relates to a gravure coating apparatus that applies a coating liquid containing solid particles to a substrate that is continuously conveyed, and in particular, the durability of a gravure roll that rapidly wears due to the influence of solid particles. It relates to technology to improve.

  A gravure roll is a cylindrical shape that adheres a certain amount of coating liquid to its outer peripheral surface while rotating, and transfers the coating liquid directly to a long substrate that is transported directly or via another roll. It is a member. Usually, the outer peripheral surface of the gravure roll is provided with a coating region in which a group of recesses (cells) is formed, and the coating liquid is attached to the coating region.

  The gravure roll is provided with a thin plate-like member (doctor blade) that scrapes off the surface of the coating area that circulates to remove excess coating liquid. For the doctor blade, in order to make the amount of coating liquid that adheres to the entire area of the coating area uniform, the pressing force that makes moderate contact with the entire area of the coating area that circulates and the abrasion that occurs due to friction with the gravure roll In order to suppress this, wear resistance is required. For this reason, although there are resin doctor blades, generally, metal doctor blades that can obtain an appropriate pressing force by bending, have high hardness, and have excellent wear resistance are often used.

  The shape of the blade edge of the doctor blade is generally square with the end of the thin plate as it is, or a blade with a sharp tip, etc., but the tip of the blade is rounded or the thickness of the tip is increased. There are various shapes such as those made thinner (for example, Patent Documents 1 to 3).

  In addition, the coating liquid used in the gravure coating apparatus is generally composed only of a liquid component, but a coating liquid containing solid particles may be used (for example, Patent Document 4). . In the gravure coating apparatus of Patent Document 4, a coating liquid containing inorganic oxide particles such as alumina powder is applied to a sheet-like battery member used for manufacturing a lithium ion secondary battery.

JP 2003-340345 A JP 2006-327170 A JP 2010-240897 A JP 2009-218053 A

  When applying a coating liquid containing solid particles, in a general gravure coating apparatus using a metal doctor blade, the gravure roll and the gravure roll and There is a problem that wear of both doctor blades proceeds rapidly.

  In particular, gravure rolls are expensive compared to doctor blades, and thus improvement in wear resistance is a very important issue in terms of cost.

  In addition, when applying to a base material used for a member that requires insulation such as an electrode material, metal powder generated by wear of a doctor blade is mixed into the coating liquid, and the final product is caused by the occurrence of an internal short circuit or the like. There is also a problem that the quality of the product may be impaired.

  Therefore, in the gravure coating apparatus of Patent Document 4, wear of the doctor blade and the gravure roll is suppressed by using a gravure roll whose surface is coated with a metal oxide and a resin doctor blade, and these wear powders are applied. Battery performance is not impaired even if mixed in the liquid.

  Since the resin doctor blade has a lower strength than the metal doctor blade, the gravure coating apparatus of Patent Document 4 uses a doctor blade having a large thickness in order to ensure an appropriate pressing force. Yes. And in that case, because it is easy to wear and wear is promoted by solid particles, the scraping amount fluctuates and the coating performance tends to become unstable, and a large amount of wear powder of the doctor blade is generated, etc. The disadvantages of using a plastic doctor blade are also suggested.

  However, when the present inventors examined, even when applying a coating liquid containing solid particles using a resin doctor blade, good coating performance was ensured by devising the configuration of the doctor blade and the like. However, it was found that the abrasion resistance of the gravure roll can be remarkably improved.

  That is, an object of the present invention is to provide a gravure coating that can improve the wear resistance of a gravure roll while ensuring good coating performance even when a coating liquid containing solid particles that promote wear is applied. It is to provide a construction device.

  The present invention relates to a gravure coating apparatus for applying a coating liquid containing solid particles to a substrate that is continuously conveyed, and the gravure coating apparatus is a coating to which the coating liquid adheres. A gravure roll having an area on the outer peripheral surface and rotating in conjunction with the conveyance of the base material, a coating liquid supply unit for supplying the coating liquid to the coating area that circulates, and the gravure roll And a doctor blade that scrapes off the surface of the coating region. The doctor blade includes an attachment portion that is detachably fixed to a blade support portion disposed in the vicinity of the gravure roll, and a protrusion portion that protrudes from the blade support portion toward the gravure roll and contacts the coating region. And the projecting portion constitutes a tip portion of the projecting portion, a blade edge portion having a hardness lower than that of the solid particles, and a portion extending from the blade edge portion to the attachment portion, And a blade base having higher rigidity than the blade tip.

  That is, in this gravure coating apparatus, first, the attachment portion is detachably fixed to the blade support portion so that the worn doctor blade can be easily replaced. And since the edge part of the doctor blade that contacts the coating region has a lower hardness than the solid particles contained in the coating liquid, the gravure roll can be scraped relatively when rubbed against the solid particles. Can be suppressed.

  And since the blade base part of the doctor blade that constitutes the part from the blade edge part to the mounting part is higher in rigidity than the blade edge part, even if the blade edge part is easily bent due to low hardness, the doctor blade The amount of deflection of the entire blade can be properly maintained. Therefore, a necessary pressing force can be applied to the doctor blade, and good coating performance can be ensured.

  Furthermore, since the contact area that rubs against the gravure roll can be reduced by reducing the thickness of the blade edge portion, the amount of friction can be reduced. In addition, since the cutting edge itself is easily bent, even if solid particles are caught, the influence on the friction is alleviated, and the wear resistance of the doctor blade and the gravure roll, particularly the wear resistance of the gravure roll can be remarkably improved.

  Specifically, the thickness of the portion within 5 mm from the cutting edge at the cutting edge is preferably 0.5 mm or less.

  Preferably, the thickness of the portion within at least 1 mm from the forefront of the cutting edge is constant.

  The cutting edge is shortened over time due to wear, but if the thickness within a range of at least 1 mm from the cutting edge of the cutting edge is constant, the doctor blade's wear resistance is improved and a stable contact state is maintained for a long time. Since it can be maintained, complicated replacement of the doctor blade can be avoided.

  Further, the protruding portion is arranged to be inclined with respect to the normal line at the contact portion with the coating region, and an inclined surface extending in the tangential direction of the contact portion is formed at the tip of the blade edge portion when not in use. You may be made to do.

  By doing so, since the blade edge part smoothly contacts the coating area from the beginning of use, it is possible to suppress the doctor blade from being caught on the gravure roll from the beginning and to ensure good coating performance. The wear resistance can be further improved.

  In this case, it is preferable that the protruding portion protrudes from the reverse direction toward the gravure roll with respect to the circumferential direction of the coating region, that is, the doctor blade is set at a reverse angle.

  If it does so, since the moderate bending and pressing force of a blade edge | tip part will be obtained, ensuring of favorable coating performance and the improvement of the abrasion resistance of a gravure roll can be implement | achieved easily.

  For example, the doctor blade may be composed of a plurality of members including a main blade having a hardness lower than that of the solid particles and a support plate supported by the blade support portion in a state of being superimposed on the main blade. In this case, the main blade and the support plate are overlapped to form the blade base portion, and the tip end side of the main blade protrudes from the support plate to form the blade edge portion.

  If the doctor blade is configured in this way, the cutting edge portion and the blade base portion can be easily configured. By adjusting the material and thickness, the rigidity of the blade base can be freely set, and the hardness and length of the blade tip can be easily adjusted, and can be easily set to an optimum state.

  In addition, the doctor blade can be configured by a single member having a hardness lower than that of the solid particles. In this case, the blade base is configured by making the thickness larger than that of the blade tip. In the case of this doctor blade, since it is composed of a single member, handling such as replacement work is easy, and workability is excellent.

  In the case where the solid particles are inorganic oxide particles and the substrate is a sheet-like member constituting an electrode material of a secondary battery, it is preferable that the cutting edge portion is made of engineering plastic. .

  By doing so, it is possible to easily obtain a blade edge portion having an appropriate hardness with respect to the solid particles, and it is possible to prevent the performance of the secondary battery from being impaired even if the wear powder of the blade edge portion is mixed into the coating liquid. .

  In this case, at least the surface portion of the coating region may be made of ceramic or DLC.

  If it does so, the abrasion resistance with respect to the coating liquid containing the particle | grains of an inorganic oxide can be improved effectively by the combination with the doctor blade which consists of polyester etc.

  In particular, the coating liquid supply unit has a chamber that is disposed along the gravure roll and includes the doctor blade and the blade support unit, and the coating liquid supply unit is configured by combining the chamber and the gravure roll. A sealed space for storing the coating liquid while supplying the coating liquid to the work area is formed, that is, the chamber may be a sealed type.

  If it does so, the vertical installation of the chamber laterally placed on a gravure roll is attained, and the gravure coating apparatus which was more excellent in coating performance and abrasion resistance is realizable.

  According to the gravure coating apparatus of the present invention, it is possible to improve the abrasion resistance of the gravure roll while ensuring good coating performance even when applying a coating liquid containing solid particles that promote wear. become able to.

It is the schematic which shows the whole structure of the gravure coating apparatus of this embodiment. It is a schematic perspective view which shows the part of a coating unit. It is a schematic sectional drawing in the arrow XX line in FIG. It is the schematic which shows the part of a doctor blade. It is the schematic which shows the 1st modification of a doctor blade. It is the schematic which shows the 2nd modification of a doctor blade. It is the schematic which shows the 3rd modification of a doctor blade. It is the schematic which shows the 4th modification of a doctor blade. It is a graph which shows the result of the abrasion test of a gravure roll.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. However, the following description is merely illustrative in nature and does not limit the present invention, its application, or its use.

<Overall configuration of gravure coating device>
FIG. 1 shows an overall configuration of a gravure coating apparatus (also simply referred to as a coating apparatus 1) in the present embodiment. The coating apparatus 1 is composed of an unwinding machine 2, a coating unit 3, a dryer 4, a winder 5, and the like. The base material W is continuously transported in a roll-to-roll manner, and in the course of transport, a coating liquid is applied to the base material W and the coating liquid is dried.

  Specifically, the uncoated base material W is set in the unwinder 2 in a roll state. When the coating apparatus 1 is actuated to start the coating process, the substrate W is continuously unwound from the unwinder 2 and guided by a plurality of rollers while adjusting the tension, and the winder It is conveyed toward 5. In the middle of the conveyance, after the coating liquid is applied to one surface of the substrate W by transfer from the gravure roll 20 in the coating unit 3, the coating liquid applied by passing through the dryer 4 is dried. Then, the coated base material W is continuously wound around the winder 5, thereby forming the coated base material W in the form of a roll.

(Base material)
In this coating apparatus 1, a sheet-like member constituting the electrode material of the lithium ion secondary battery is a base material W. Specific examples of the substrate W include a separator film disposed between the positive electrode sheet and the negative electrode sheet of the lithium ion secondary battery. In that case, in this coating apparatus 1, the process which forms a flame-retardant insulating layer with a thickness of several micrometers to several tens of micrometers on the surface of the separator film is performed by applying a coating liquid to one surface of the separator film. Is called.

  Another specific example of the substrate W is a negative electrode sheet in which an active material layer such as graphite is formed on the surface of a metal thin film such as a copper foil. In that case, in this coating apparatus 1, the process which forms a flame retardant insulating layer with a thickness of several micrometers-several tens of micrometers on an active material layer by apply | coating a coating liquid to the single side | surface of the negative electrode sheet. Done.

(Coating solution)
The coating liquid that forms these flame-retardant insulating layers contains solid particles. Specifically, the flame retardant contains a large amount of fine particles of alumina (aluminum oxide) which is an inorganic oxide. Alumina has properties such as non-conductivity, high hardness, and high melting point, and its fine particles have a very high hardness so as to be used as an abrasive. Although the hardness depends on purity, it is at least 1000 Hv or more, and is generally about 1200 to 1800 HV. Moreover, the particle size is about 0.1-10 micrometers (average particle diameter). The solid particles are not limited to alumina, but may be fine particles such as magnesium oxide, silica, titanium oxide, and zirconium oxide.

  Since the coating liquid that is normally used is composed of only liquid components, when using a special coating liquid containing such fine particles in a conventional gravure coating device, ensuring the uniformity of the fine particle concentration and consumable parts. Various problems occur, such as ensuring durability. Among them, in particular, rapid wear of gravure rolls due to the influence of fine particles is a very important issue. Since the gravure roll is an expensive part, the higher the replacement frequency, the higher the running cost. As the work load increases, workability also decreases.

  Therefore, in this coating apparatus 1, even when a coating liquid containing solid particles is applied, the coating unit 3 is provided so that the abrasion resistance of the gravure roll is significantly improved while maintaining the coating performance. In particular, the doctor blade 50 described later is devised.

(Coating unit)
2 and 3 show details of the coating unit 3. The coating unit 3 includes an upper guide roll 11, a lower guide roll 12, a gravure roll 20, a coating liquid supply unit 30, and the like.

  The upper guide roll 11 and the lower guide roll 12 are arranged in parallel to each other apart in the vertical direction in the middle of the transport path of the substrate W. The upper guide roll 11 and the lower guide roll 12 are both supported by a device frame (not shown) in a state of being rotatable about a horizontal axis extending in a substantially horizontal direction. The back surface of the base material W at the time of transport is supported by the upper guide roll 11 and the lower guide roll 12 while being pulled with a constant tension in the transport direction, and the base material W is supported by the lower guide roll 12. The upper and lower guide rolls 11 travel upward in the vertical direction (substantially vertical direction) at a controlled speed.

(Coating liquid supply part)
The coating liquid supply unit 30 includes a storage tank 31, a liquid feed pump 32, a liquid feed pipe 33, a liquid return pipe 34, a chamber 40, and the like. The storage tank 31 is a container that stores the coating liquid, and is installed at a lower position than the chamber 40. The storage tank 31 is connected to the chamber 40 via a liquid feeding pipe 33. A liquid feed pump 32 is installed in the middle of the liquid feed pipe 33, and the coating liquid is supplied from the storage tank 31 to the chamber 40 by the discharge force of the liquid feed pump 32.

  The storage tank 31 is also connected to the chamber 40 via a liquid return pipe 34. Since the return liquid pipe 34 is arranged so as to descend from the chamber 40 toward the storage tank 31, the coating liquid overflowing in the chamber 40 is returned to the storage tank 31 through the return pipe 34 by free fall. . Accordingly, during coating, the coating liquid continuously circulates between the storage tank 31 and the chamber 40.

  When the coating liquid contains a large amount of fine particles, if the distribution of the fine particles is uneven in the coating liquid, the coating performance may be reduced. By circulating the coating liquid in this way, the fine particles in the coating liquid may be reduced. Since it can always be kept in a dispersed state, stable coating can be performed. The coating liquid is supplied to the gravure roll 20 through the chamber 40.

(Chamber)
The chamber 40 is a horizontally long structure and is disposed along the side of the gravure roll 20. The chamber 40 includes a chamber body 41, a doctor blade 50, a seal blade 43, a side seal 44, a pressing tool 45, and the like. The chamber body 41 has the same length as the gravure roll 20 and is formed using alumina. On one of the side surfaces of the chamber body 41 (side surface facing the gravure roll 20), a horizontally long recess (horizontal long recess 41a) is formed.

  On the upper side of the horizontally long recess 41a, an upper support portion 41b having a flat blade support surface is provided along the upper edge of the horizontally long recess 41a. A lower support portion 41c having a flat blade support surface is provided along the lower edge of the horizontally elongated recess 41a below the horizontally elongated recess 41a. A pressing tool 45 is detachably attached to each of the upper support portion 41b and the lower support portion 41c by fastening with a plurality of bolts.

(Basic configuration of doctor blade)
The doctor blade 50 is a strip-shaped member that scrapes off the surface of a coating region 21 of the gravure roll 20 to be described later, and is arranged along the upper side of the side of the gravure roll 20. The seal blade 43 is a strip-shaped member that closes the gap between the surface of the coating region 21 and is arranged along the lower side of the side of the gravure roll 20 so as to face the doctor blade 50 in the vertical direction. Has been. In the coating apparatus 1, the doctor blade 50 and the seal blade 43 are shared, and the structures of the doctor blade 50 and the seal blade 43, and the upper support portion 41b and the lower support portion 41c are vertically symmetrical. .

  The doctor blade 50 is detachably fixed to the chamber 40 by sandwiching a proximal end portion (attachment portion 51) of the doctor blade 50 between the upper support portion 41 b and the pressing tool 45. That is, a blade support portion that supports the doctor blade 50 is configured by the upper support portion 41 b and the pressing tool 45 so that the doctor blade 50 can be easily replaced.

  A portion (projecting portion 52) on the distal end side of the doctor blade 50 projects from the blade support portion toward the gravure roll 20 and is in contact with the coating region 21. The doctor blade 50 scrapes off the surface of the coating area 21 to remove excess coating liquid, whereby the amount of the coating liquid adhering to the entire coating area 21 is adjusted uniformly. The details of the doctor blade 50 will be described later.

  One inflow port 41d is formed on the lower side of the central portion in the longitudinal direction of the horizontally long recess 41a. The inflow port 41d opens at the corner of the boundary between the lower end of the bottom surface of the horizontally long recess 41a and the lower support portion 41c, and is connected to the liquid supply pipe 33 through the liquid supply passage.

  Two outflow ports 41e are formed on the upper side of each end portion in the longitudinal direction of the horizontally long concave portion 41a. Each inflow port 41d opens at the corner of the boundary between the upper end portion of the bottom surface of the horizontally elongated recess 41a and the upper support portion 41b, and is connected to each end portion of the return pipe 34 branched to the left and right through the return passage. Yes. The total opening area of these outlets 41e is larger than the opening area of the inlet 41d.

  Side seals 44 are attached to the respective end surfaces of the chamber body 41, and the side seals 44, 44 close the gaps between the both ends of the horizontally elongated recess 41 a and both ends of the doctor blade 50 and the seal blade 43. It is peeling. The chamber 40 thus integrally formed is combined with the gravure roll 20.

(Gravure roll)
The gravure roll 20 has a horizontally long cylindrical shape and is formed of ceramic having excellent wear resistance. In light of coating performance and the like, the diameter of the gravure roll 20 is preferably 40 to 150 mm, and particularly preferably 60 to 120 mm. The gravure roll 20 is located at a height between the upper guide roll 11 and the lower guide roll 12, and is disposed in parallel with the surface in contact with the surface of the substrate W.

  The gravure roll 20 is supported by a device frame (not shown) so as to be rotatable around the horizontal axis, and the outer peripheral surface of the gravure roll 20 rotates in the direction opposite to the conveyance direction of the substrate W at the contact portion with the substrate W. In addition, the motor 22 is driven to rotate in conjunction with the conveyance of the substrate W (kiss reverse method).

  In a certain region (coating region 21) on the outer peripheral surface of the gravure roll 20, a large number of dents (cells) arranged in a uniform pattern are formed. The coating liquid is continuously supplied from the chamber 40 to the coating area 21 that circulates as the gravure roll 20 rotates, and the coating liquid adhering to the coating area 21 is transferred to the surface of the substrate W to be transported. It has come to be.

  In addition, you may coat | cover the surface part of the outer peripheral surface (including the coating area | region 21) of the gravure roll 20 with a protective film with high hardness. In that case, the main material of the gravure roll 20 may be a metal. For example, the surface portion of a metal gravure roll may be covered with ceramic, or the surface portion of a metal or ceramic gravure roll may be covered with diamond-like carbon (DLC). If it does so, the gravure roll 20 excellent in abrasion resistance with respect to the coating liquid containing a solid particle is realizable at low cost.

  The chamber 40 is combined with the gravure roll 20 by being placed on the gravure roll 20 so that the doctor blade 50 and the seal blade 43 are pressed against the coating region 21. By doing so, a sealed space (liquid reservoir 46) in which the coating liquid is stored is formed between the gravure roll 20 and the chamber 40. At the time of coating, since the inside of the liquid reservoir 46 is filled with the coating liquid, a part of the coating region 21 (liquid contact portion) facing the liquid reservoir 46 is always in contact with the coating liquid. The coating liquid is supplied to the gravure roll 20 through the region.

  In the liquid reservoir 46, since the coating liquid flows in from the lower inlet 41d and flows out of the upper outlet 41e, a flow of the coating liquid from the lower side to the upper side is formed. In addition, since the wetted part circulates at a high speed upward, the coating liquid is smoothly introduced from the inlet 41d and wound up by the gravure roll 20 at the lower part of the liquid reservoir 46, so that the liquid pressure is low, Wear is relatively difficult to occur at the lower part of the inner surface of the seal blade 43 and the horizontally long recess 41a.

  On the other hand, in the upper part of the liquid reservoir 46, the flow rate of the coating liquid increases, so that the liquid pressure tends to increase and the flow tends to be disturbed. Therefore, when the coating liquid contains a large amount of fine particles, the frictional resistance of the coating liquid is increased at the upper part of the liquid reservoir 46, so that wear on the inner surfaces of the doctor blade 50 and the horizontally elongated recess 41a is likely to occur. In particular, the portion where the doctor blade 50 is in contact with the gravure roll 20 is rubbed in a state where the coating liquid is interposed, and thus wear progresses rapidly.

  Therefore, first, in the coating unit 3, the outlet 41e is provided at both ends of the upper portion of the liquid reservoir 46, and the total opening area is made larger than that of the inlet 41d, so that the coating liquid is dispersed throughout the liquid reservoir 46. In this way, the liquid pressure at the upper part of the liquid reservoir 46 is suppressed from becoming excessively high. And the structure of the doctor blade 50 is devised so that the abrasion resistance in the contact part of the doctor blade 50 and the gravure roll 20, especially the abrasion resistance of the gravure roll 20 is improved.

(Specific configuration of doctor blade)
Specifically, as shown in FIGS. 4 to 8, solid particles (in the present embodiment) in which the coating liquid contains tip portions (blade edge portions 52 a) of the protrusions 52 of the doctor blade 50 that contact the gravure roll 20. The hardness is lower than that of the alumina particles), that is, the doctor blade 50 is easily scraped when rubbed against the solid particles, and the rigidity of the intermediate portion (blade base portion 52b) of the protruding portion 52 extending from the blade edge portion 52a to the mounting portion 51. Is higher than the blade edge portion 52a, that is, it is difficult to bend except for the blade edge portion 52a even when a lateral load is applied to the protruding portion 52. By doing so, the wear resistance of the doctor blade 50 and the gravure roll 20 can be improved while ensuring good coating performance, and in particular, the wear resistance of the gravure roll 20 can be remarkably improved.

  That is, by increasing the rigidity of the blade base 52b that occupies most of the protrusion 52, even if the hardness is lowered and the blade edge 52a is easily bent, the amount of bending of the entire protrusion 52 can be properly maintained. Sufficient pressing force can be given to the part 52, and favorable coating performance can be ensured. In the case of rubbing against the solid particles, the doctor blade 50 is easily scraped, so that the gravure roll 20 can be relatively prevented from being scraped. And since the area which rubs with the gravure roll 20 can be made small by reducing the thickness of the blade edge part 52a, the amount of friction can be reduced. In addition, since the blade edge portion 52a itself is easily bent, even if solid particles are caught, the influence on the friction is alleviated, so that the wear resistance of the doctor blade 50 and the gravure roll 20, particularly the wear resistance of the gravure roll 20 can be remarkably improved. become.

  Specifically, it is set so that the thickness T (the thickest portion) of the portion L within 5 mm from the foremost edge in the cutting edge portion 52a that may be worn and come into contact with the gravure roll 20 is 0.5 mm or less. Is preferred. Furthermore, it is more preferable to set the thickness T of the portion L within 3 mm to 0.35 mm or less, and it is even more preferable to set the thickness T of the portion L within 2 mm to 0.5 mm or less. In addition, it is preferable to set the part L which can be worn to 1 mm or more from the forefront. The thickness T depends on the material, but is preferably set to 0.05 mm or more from the viewpoint of strength.

  As shown in FIG. 4, the doctor blade 50 of this embodiment is composed of a plurality of members including a main blade 55 and a support plate 56. Each of the main blade 55 and the support plate 56 is a strip-shaped member having a constant thickness. The long sides of the main blade 55 and the support plate 56 are substantially the same size as the gravure roll 20, and the short side of the support plate 56 is set smaller than the short side of the main blade 55. For example, the short side of the main blade 55 can be set to 35 mm, and the short side of the support plate 56 can be set to 30 mm.

  The main blade 55 is made of a synthetic resin having excellent insulating properties. The type may be a general-purpose synthetic resin such as polyethylene, but engineering plastics having high hardness and rigidity, such as polyester, polyacetal, reinforced polyester (glass fiber reinforced polyester), and polycarbonate are preferable. The thickness of the main blade 55 is preferably set to 0.5 mm or less.

  The support plate 56 may be a material having high rigidity, and is preferably a metal such as stainless steel or ceramic, but may be a synthetic resin. For example, a stainless steel plate having a thickness of 1.0 mm can be used for the support plate 56.

  The support plate 56 is superposed on the surface of the main blade 55 facing the liquid reservoir 46 and is shifted by the upper support 41b and the pressing tool 45 (blade support) while the end of the protrusion 52 is shifted. It is pinched. Accordingly, in the doctor blade 50 of the present embodiment, the main blade 55 and the support plate 56 are overlapped to form the blade base portion 52b, and the distal end side of the main blade 55 protrudes from the support plate 56 to form the blade edge portion 52a. .

  Thus, if the doctor blade 50 is comprised by the main blade 55 and the support plate 56, the blade edge | tip part 52a and the blade base part 52b which were mentioned above can be comprised easily. By adjusting the material and thickness, the rigidity of the blade base 52b can be freely set. It is easy to set the hardness and length of the cutting edge portion 52a, and it is possible to easily set an optimum state.

  The cutting edge 52a of the doctor blade 50 is set so as to contact the coating region 21 at a reverse angle of 30 to 40 °. In other words, the protruding portion 52 protrudes from the opposite direction to the gravure roll 20 with respect to the circumferential direction of the coating region 21 and is inclined with respect to the normal H at the contact portion with the coating region 21. . And the inclination angle (theta) of the blade edge | tip part 52a from the tangent S in a contact part seeing from the direction of the rotating shaft of the gravure roll 20 is set in the range of 30-40 degrees.

  By setting the cutting edge portion 52a of the doctor blade 50 in this way, appropriate bending and pressing force of the cutting edge portion 52a can be obtained, so that it is possible to ensure good coating performance and improve the abrasion resistance of the gravure roll 20. It can be easily realized. If it is a natural angle (the protrusion 52 protrudes from the forward direction toward the gravure roll 20 with respect to the circumferential direction of the coating region 21), solid particles are likely to accumulate around the cutting edge, but if it is a reverse angle Since such deposition can be prevented, high coating performance can be secured. Further, even if the gravure roll 20 rotates at a high speed, the cutting edge 52a that is likely to occur at a natural angle is unlikely to be lifted, which is advantageous in terms of excellent production efficiency.

  Furthermore, in this coating apparatus 1, the inclined surface 57 which spreads in the direction of the tangent S is formed in the front-end | tip of the blade edge | tip part 52a at the time of unused, and the front-end | tip of the blade edge | tip part 52a is a coating area | region from the stage of use start. 21 is set so as to make smooth contact. Therefore, since it can suppress from the beginning that the doctor blade 50 is caught in the gravure roll 20, abrasion resistance can be improved more, ensuring favorable coating performance.

  The cutting edge 52a is gradually shortened due to wear, but since the entire thickness of the cutting edge 52a is constant, a stable contact state can be maintained even if the cutting edge 52a is shortened. In addition, in this coating apparatus 1, since the wear resistance of not only the gravure roll 20 but also the doctor blade 50 can be improved, the thickness of at least 1 mm or less from the foremost edge of the blade edge portion 52a toward the blade base portion 52b is made constant. If so, complicated replacement of the doctor blade 50 can be avoided.

(First variant of doctor blade)
FIG. 5 shows a doctor blade 50A of a first modification. The doctor blade 50A is different from the doctor blade 50 of the embodiment in that it is configured by a single member. That is, in the case of this doctor blade 50A, the attachment part 51 and the whole projecting part 52 are formed of synthetic resin having a hardness lower than that of solid particles, and the blade base part 52b is made thicker than the blade edge part 52a. Is configured.

  Specifically, the blade edge 52a having a constant thickness is connected to the blade base 52b via a stepped portion 61 that lowers the inner surface of the protrusion 52 (the surface facing the liquid reservoir 46). The boundary portion between the inner surfaces of the cutting edge portion 52a and the blade base portion 52b in the stepped portion 61 is formed by a curved surface having an arcuate cross section. In the case of this doctor blade 50A, since it is composed of a single member, there is an advantage that it is easy to handle replacement work or the like and is excellent in workability. For the sake of convenience, the same reference numerals are used for the same functional configuration, and the description thereof is omitted (the same applies to other modified examples).

(Second modification of doctor blade)
FIG. 6 shows a doctor blade 50B of a second modification. The doctor blade 50B is different from the doctor blade 50 of the embodiment in that the main blade 55 has the form of the doctor blade 50A of the first modified example. That is, in the case of this doctor blade 50B, the main blade 55 has a thin portion 71 constituting the cutting edge portion 52a and a thick portion 72 constituting the blade base portion 52b, which is thicker than the thin portion 71. .

  In the case of this doctor blade 50B, the blade base portion 52b is supported by the high-rigidity portion 73 formed by overlapping the thick portion 72 and the support plate 56, and the portion on the blade edge portion 52a side of the thick portion 72. The intermediate rigid portion 74 is formed to protrude from the plate 56 and has a lower rigidity than the high rigid portion 73. Thus, if the rigidity of the blade base portion 52b is increased stepwise, the blade edge portion 52a can be bent in a more balanced manner, so that it is possible to further ensure the favorable coating performance and improve the wear resistance. Can be realized.

(Third modification of doctor blade)
FIG. 7 shows a doctor blade 50C of a third modified example. The doctor blade 50C is composed of a single member similarly to the doctor blade 50A of the first modification, and the shape of the cutting edge portion 52a is different from that of the doctor blade 50A of the first modification.

  Specifically, the thickness of the blade edge portion 52a is not constant, and is formed in a tapered shape in which the thickness gradually decreases toward the tip side. More specifically, the inner surface of the blade edge portion 52a is a flat inclined surface that gradually approaches the outer surface toward the tip side. In the case of this doctor blade 50C, when the blade edge portion 52a is worn, the thickness gradually increases and it becomes difficult to obtain an effect. However, the blade edge portion 52a becomes difficult to bend gradually as it moves away from the tip, so that the thickness of the tip is extremely reduced. There is an advantage that the cutting edge portion 52a can be stably pressed against the gravure roll 20 with a sufficient pressing force even if it is reduced.

(Fourth modification of the doctor blade)
FIG. 8 shows a doctor blade 50D of the fourth modified example. The doctor blade 50D is different from the main blade 55 of the second modification in that the main blade 55 has the form of the doctor blade 50C of the third modification.

  That is, in the case of this doctor blade 50D, the main blade 55 has a tapered tip portion 81 that constitutes the cutting edge portion 52a, and a main body portion 82 that is continuous with the tip portion 81 and constitutes the blade base portion 52b, and a constant thickness. have. The blade base 52b of the doctor blade 50D includes a high-rigidity portion 73 formed by overlapping the main body portion 82 and the support plate 56, and a portion on the distal end portion 81 side of the main body portion 82 protruding from the support plate 56. And a medium rigid portion 74 formed. Therefore, in the case of this doctor blade 50D as well, the cutting edge portion 52a can be bent in a more balanced manner, so that it is possible to more reliably realize a satisfactory coating performance and an improved wear resistance.

<Abrasion test of gravure roll>
The effect of the difference in the thickness of the cutting edge of the resin doctor blade on the wear of the gravure roll was investigated. The test results of the comparative example (thickness of the blade edge part 1 mm), Example 1 (thickness of the blade edge part 0.2 mm), and Example 2 (thickness of the blade edge part 0.35 mm) are shown below.

  In the test, a coating gravure roll made of ceramic was installed, and a coating test machine set so that the blade edge of the doctor blade was in contact with the coating area of the gravure roll at a reverse angle of about 35 ° was used. Continuous coating was performed under the test conditions. In each test, the change in the cell depth in the coating area was measured, and the amount of change was evaluated as the amount of wear. The cell depth was measured by using Surfcom 130A manufactured by Tokyo Seimitsu Co., Ltd., tracing a predetermined portion of the coating region three times, and taking the average value as the cell depth.

  The configurations of the doctor blades of the comparative example, example 1, and example 2 are as follows.

  (Comparative Example) A doctor blade made of resin (reinforced polyester) having a thickness of 1 mm and a short side length of 35 mm. An inclined surface is formed at the tip of the cutting edge before use so as to smoothly contact the coating region.

  (Example 1) This is a doctor blade made of resin (reinforced polyester) in the same form as the first modification described above. The blade tip has a thickness of 0.2 mm and a length of 1.5 mm, and the blade base has a thickness of 1 mm. The short side length including the cutting edge is 35 mm.

  (Example 2) A doctor blade of the same form as the above-described embodiment. The main blade is made of a resin (polyester) main blade having a thickness of 0.35 mm and a short side length of 35 mm, and a stainless steel support plate having a thickness of 1 mm and a short side length of 30 mm.

  In FIG. 9, the graph showing the time-dependent change of the abrasion loss of these gravure rolls is shown. In the comparative example, the wear amount tended to increase as the coating time passed. On the other hand, in Example 1 and Example 2, the tendency for the amount of wear to decrease significantly was recognized compared with the comparative example. In Example 2, the amount of change in wear was 1/3 or less compared to the comparative example, and a remarkable effect of improving the wear resistance of the gravure roll was recognized. In particular, in Example 1 in which the blade edge portion is thinner, the wear amount of the gravure roll was at an error level even after about 30 hours, and a remarkable effect was observed that the gravure roll was hardly worn.

  In addition, as for the state of the coating area after scraping with a doctor blade, both Example 1 and Example 2 were found to have a tendency to uniformly adhere the coating liquid to the same level as before, and thus good. It was suggested that good coating performance could be secured.

  Therefore, according to the gravure coating apparatus 1 of the present embodiment and each modified example, a gravure roll while ensuring good coating performance even when a coating liquid containing solid particles that promote wear is applied. The wear resistance of 20 can be remarkably improved.

  In addition, the gravure coating apparatus concerning this invention is not limited to embodiment mentioned above, The other various structure is also included.

  For example, in the embodiment, the so-called kiss coat type coating unit 3 is exemplified, but the coating method of the coating unit 3 is not limited thereto. For example, there are a direct system in which the coating liquid is transferred with the substrate W sandwiched between the gravure roll 20 and the backup roll, and an offset system in which the coating liquid is transferred between the gravure roll 20 and the substrate W via a rubber roll or the like. May be.

  The seal blade 43 may not be shared with the doctor blade 50, and the material and shape may be different from the doctor blade 50. The material of the blade edge portion 52a is preferably a resin, but may be a metal as long as the hardness is lower than that of solid particles.

DESCRIPTION OF SYMBOLS 1 Gravure coating apparatus 3 Coating unit 20 Gravure roll 21 Coating area 30 Coating liquid supply part 40 Chamber 41a Horizontal elongate recessed part 41b Upper side support part 41d Inlet 41e Outlet 45 Pressing tool 46 Liquid reservoir part 50, 50A, 50B, 50C , 50D Doctor blade 51 Mounting portion 52 Projection portion 52a Blade tip portion 52b Blade base portion 55 Main blade 56 Support plate 57 Inclined surface W Substrate

Claims (10)

A gravure coating device that applies a coating liquid containing solid particles to a substrate that is continuously conveyed,
A gravure roll having a coating area to which the coating liquid adheres on the outer peripheral surface and rotating in conjunction with the conveyance of the substrate;
A coating liquid supply unit that supplies the coating liquid to the coating region that circulates;
A doctor blade disposed along the gravure roll and scraping the surface of the coating area;
With
The doctor blade is
A mounting portion detachably fixed to a blade support portion disposed in the vicinity of the gravure roll;
Projecting toward the gravure roll from the blade support, and a projecting part that contacts the coating region;
Have
The protrusion is
The tip portion of the protruding portion is configured, and the cutting edge portion having a lower hardness than the solid particles,
A portion extending from the blade edge portion to the attachment portion, and a blade base portion having higher rigidity than the blade edge portion;
Gravure coating equipment. In the gravure coating apparatus according to claim 1,
A gravure coating apparatus in which the thickness of a portion within 5 mm from the forefront of the cutting edge is 0.5 mm or less. In the gravure coating apparatus according to claim 2,
A gravure coating apparatus in which the thickness of a portion within at least 1 mm from the cutting edge of the cutting edge is constant. In the gravure coating apparatus according to claim 2 or claim 3,
The protruding portion is disposed to be inclined with respect to a normal line at a contact portion with the coating region,
A gravure coating apparatus in which an inclined surface extending in a tangential direction of the contact portion is formed at the tip of the blade edge when not in use. In the gravure coating apparatus according to claim 4,
The gravure coating apparatus with which the said protrusion part protrudes toward the said gravure roll from the reverse direction with respect to the surrounding direction of the said coating area | region. In the gravure coating apparatus according to claim 1,
The doctor blade is
A main blade having a lower hardness than the solid particles;
A support plate supported by the blade support in a state of being superimposed on the main blade;
A plurality of members including
The main blade and said support plate is formed said blade base overlap, the main blade tip side gravure coating apparatus before Symbol cutting edge is configured to protrude from the support plate. In the gravure coating apparatus according to claim 1,
The doctor blade is composed of a single member having a lower hardness than the solid particles,
A gravure coating apparatus in which the blade base is configured by making the thickness larger than the blade tip. In the gravure coating apparatus according to claim 1,
The solid particles are inorganic oxide particles,
The said base material is a gravure coating apparatus which consists of engineering plastics. In the gravure coating apparatus according to claim 8,
A gravure coating apparatus in which at least a surface portion of the coating region is made of ceramic or DLC. In the gravure coating apparatus according to any one of claims 1 to 9,
The coating liquid supply unit includes a chamber that is disposed along the gravure roll and includes the doctor blade and the blade support unit.
A gravure coating apparatus in which an airtight space for storing the coating liquid is supplied to the coating region by a combination of the chamber and the gravure roll.

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