JP2005161152A - Coater - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a coater suitable for use in a variety of coating works, high in coating accuracy, and resistant to staining. <P>SOLUTION: The coater 1 comprises a web 2 which is carried in a manner slanted downward at a specified angle and is coated with a coating material t, a coating means 3 which spouts the coating material t toward the surface of the web 2 from the above to form a coating material curtain tc and coats the surface of the web 2 with the coating material t to form a coating layer t1, and a coating material scraping means 5 which is arranged downstream of the web carrying direction of the coating means 3, pressing a scraping member 5b from the lower part against the coating layer t1 of the web 2 wound around a backing roll 4, and scrapes off the surplus of the coating material t in the coating layer t1 of the web 2. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a coating apparatus for applying a paint to a web such as paper.

  2. Description of the Related Art Conventionally, coated paper used for catalogs, thermal paper, automatic ticket gates, and the like is generally produced by applying a paint on the surface of a web as a base paper by a blade coater.

  A machine for applying such a coating is generally called a coating machine, and the coating machine includes a line having a coating coating process using a blade coater and a drying process for the applied coating.

  The coating process by the blade coater is performed through the following process.

  As shown in FIG. 3 which is a conceptual front sectional view of the blade coater, the web 102 discharged from a winder (not shown) is wound around a rotating backing roll 103 and conveyed as indicated by an arrow s.

  Then, the coating material t is sprayed from the head 104 toward the coating surface 102n of the web 102 to apply a large amount of coating material t, and the coating material t applied by the blade 105 disposed on the upstream side is scraped off to a predetermined amount. (Arrow ty in FIG. 3).

  In this way, the web 102 having the coating material t applied on one side is transported to a dryer (not shown), and the coating material t applied is dried.

  Subsequently, application of the coating t and drying thereof are performed in the same manner, with the surface opposite to the surface on which the coating t is applied in the web 102 as a new application surface.

  Next, the web 102 is repeatedly applied with another paint on both sides of the web 102 to which the paint t is applied by repeating the same process as described above.

  The blade coater is suitable for a wide variety of paints, has a long history, has been used for many years, and has excellent high-speed stability.

  On the other hand, in recent years, a curtain coater that performs coating by spraying a paint from above on a web application surface like a curtain is also being performed.

In addition, there exists the following patent document 1 as literature well-known invention which concerns on this application.
Japanese Utility Model Publication No. 6-64765

  By the way, in the above-described blade coater, the coating material t is sprayed from the head 104 toward the coating surface 102n of the upper web 102, and the sprayed coating material t is scraped off by the blade 105. The amount of paint t used is larger than the amount actually applied, and requires 10 to 15 times the amount.

  Further, since the coating material t is blown upward from the head 104, the coating material t adheres to the nozzles 104n of the head 104 and needs to be contaminated and cleaned, which causes a problem in maintenance.

  On the other hand, the curtain coater blows the paint downward, so it has the advantage of having a very simple structure, but depending on the coating conditions such as web transport speed, coating amount, paint properties, etc. There is a region where is not stable.

  SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and an object thereof is to provide a coating apparatus that has a wide range of coating suitability, high coating accuracy, and is resistant to contamination.

    In order to achieve the above object, a coating apparatus according to claim 1 of the present invention is a coating apparatus that applies a paint onto a web surface while conveying a web, and is inclined downward by a predetermined inclination angle. A web to be transported and coated with paint, a coating curtain to form a paint curtain by jetting paint from above toward the web surface, and a coating means for coating the web surface to form a coating layer. And a paint scraping means for scraping off the excess paint in the web coating layer by pressing the scraping member from below toward the web coating layer wound around the backing roll. It is characterized by providing.

  The coating apparatus according to claim 2 of the present invention is the coating apparatus according to claim 1, wherein the scraping member of the paint scraping means is pressed while the outer peripheral surface is pressed against the coating layer of the web and rotates. It is a rotatable round bar-like body that scrapes off excess paint in the web coating layer.

  A coating apparatus according to a third aspect of the present invention is the coating apparatus according to the first or second aspect, wherein the web is arranged and conveyed at a predetermined position upstream in the web conveyance direction with respect to the paint curtain. The air cut device that blows a high-speed air flow toward the anti-conveying direction of the web with respect to the coating application surface of the air, blows off the air on the coating application surface of the web conveyed by the high-speed air flow of the air cutting device, and paint It is characterized by preventing curtain disturbance.

    According to the coating apparatus relating to the first aspect of the present invention, since the coating material is ejected downward from the coating device, the coating device does not adhere to the coating device and is prevented from being stained.

  Further, since the paint is ejected downward from the application means, it is accelerated by the gravitational acceleration and is applied smoothly, and the amount of paint to be used can be reduced.

  In addition, since the web is conveyed and applied at a predetermined inclination angle downward, the paint can be uniformly applied to the web according to conditions such as the viscosity and flow rate of the paint.

  In addition, because the excess paint in the web coating layer is scraped off by the scraping member of the paint scraping means, it can be applied to various types of base paper such as base paper, paint, etc., which have poor coating suitability, and combinations of paint types. It can respond flexibly, has a wide range of coating suitability, and improves the smoothness of the coating layer surface and the adhesion of the coating to the web.

  According to the coating apparatus according to claim 2 of the present invention, the round bar-like body of the paint scraping means scrapes off the excess paint in the web coating layer while rotating, so that the paint is the outer peripheral surface of the round bar-like body. It is possible to use the paint scraping means cleanly without causing clogging between the coating layers of the web and to obtain a predetermined quality without causing streaks on the surface of the coating layer of the web.

  According to the coating apparatus according to claim 3 of the present invention, since the air cut device blows off the air on the planned application surface of the web by the high-speed air flow, the coating curtain is prevented from being disturbed and the coating of the coating on the web surface is performed. It can be performed normally and perform highly reliable coating processes.

  As shown in FIG. 1 which is a conceptual front view, a coating apparatus 1 according to an embodiment of the present invention transports a web 2 which is a base paper in the direction of arrow A via a transport roll r (r1 to r8). This is an apparatus for applying the coating material t to one side of the web 2.

  The coating apparatus 1 is installed in a casing 6, and a curtain head 3 for spraying a coating material t from above to form a coating material curtain tc and applying the coating material t to the web 2 to be conveyed. The backing roll 4 that is arranged downstream in the web conveying direction and rotates in the direction of the arrow, is pressed against the coating layer t1 (described later) of the coating t on the surface of the web 2 wound around the backing roll 4, and the excess of the coating t is removed. And a metering device (paint scraping means) 5 having a blade (scraping member) 5b for scraping.

  As shown in FIG. 2A, which is an enlarged front sectional view of the curtain head 3, and in FIG. 2B, which is a right side view, the paint t applies a predetermined pressure by a pump (not shown). The header 3h supplies the paint t through the nozzle 3n toward the upper surface of the web 2 as a uniform liquid film-like paint curtain TC having a film thickness a of 0.3 to 0.5 mm, for example. A coating layer t1 of the coating material t is formed on the surface of the web 2 by being ejected from above.

  Here, as shown in FIGS. 1 and 2A, the web 2 between the transport rolls r5 and r6 applied by the paint curtain tc is transported with an inclination angle θ ° downward in the transport direction. Has been.

  The width 3b of the nozzle 3n is 0.3 to 0.5 mm, and the flow rate of the curtain head 3 is 5 to 100 liters / minute and the web width 1 m. It is not limited.

  As shown in FIG. 2 (b), the paint curtain tc is ejected with a width dimension equal to or larger than the width of the web 2 so that the paint t is applied without being left uncoated on the surface of the web 2. The paint t received by the color pan 7 is collected.

Here, as shown in FIG. 2A, an air cut device 8 may be provided on the upstream side in the web conveyance direction of the paint curtain tc.

  When the web 2 is transported at a speed of about 300 m / min or more, the air cut device 8 has air (air) on the surface of the transported web 2 due to the viscosity of the air, and the paint curtain tc is caused by the wind. It is a device to prevent things from being disturbed and unpainted.

  This air-cut device 8 is a device that supplies air as a high-speed air flow k having a wind speed of 60 to 100 m / sec through a duct (not shown) by a fan (not shown), and the conveyance direction of the web 2 (see FIG. A high-speed air flow k with a wind speed of 60 to 100 m / second is applied onto the application surface 2n of the web 2 in the opposite conveyance direction (the direction of arrow B in FIG. 2A), which is the opposite direction of the arrow A in FIG. Air blown on the planned application surface 2n of the web 2 to be conveyed is blown away.

  In addition, the distance l1 between the front-end | tip part 8s of the air cut apparatus 8 and the blower outlet of the high-speed airflow k is set to 50-150 mm.

  If the distance l4 is too short, the first paint curtain tc1 is shaken by the high-speed air flow a. Conversely, if the distance l4 is too long, the sealing performance is good, but the web 2 sticks to the outlet of the air cut device 6. If the web 2 is transported in the sucked state, the surface of the web 2 is damaged.

  Then, when using a higher speed air flow a, for example, a wind speed of 80 to 100 m / second, it is confirmed that the distance l4 needs 110 to 120 mm, and the optimum value of the distance l4 is 110 to 120 mm. Has been.

  Note that the distance c between the outer peripheral surfaces of the transport roll r5 and the transport roll r6 before and after the curtain head 3 shown in FIG. 1 is preferably short, but the air cut device 8, the color pan 7 and the like are disposed. ˜1000 mm.

  As shown in FIG. 1, the metering device 5 has a flat blade 5 b, presses the blade 5 b against the coating layer t on the surface of the web 2, and the web 2 on which a large amount of the paint t is applied. This is an apparatus for scraping off and removing excess paint t from the coating layer t1 on the surface.

  The metering device 5 presses the blade 5b against the coating layer t1 of the web 2 wound around the peripheral surface of the backing roll 4, and changes the scraping amount of the paint t by changing the pressing force, thereby changing the predetermined coating film. The layer t1 thickness is obtained.

  Therefore, the metering device 5 has an adjusting device 5b1 for adjusting the blade 5b so that the blade 5b can advance and retreat in the thickness direction of the web 2 on the peripheral surface of the backing roll 4.

  For example, a stainless steel (SUS) plate having a thickness of 0.1 to 0.7 mm is used for the blade 5b, and the distance to the web 2 surface is adjusted by the adjusting device 5b1.

  The adjusting device 5b1 is configured to adjust by changing the pressing force to the blade 5b by rotating the adjusting screw. The adjusting device 5b1 has an interval of about 50 mm in the width direction of the blade 5b (perpendicular to the paper surface of FIG. 1). A plurality are provided.

  Here, when the blade 5b used in a fixed state is used as the metering device 5, the coating material t is clogged between the blade 5b and the web 2 surface against which the blade 5b is pressed, or the surface of the coating layer t1 on the web 2 May cause streaks.

  Therefore, instead of the blade 5b used in a fixed state, a round rod-shaped rod (round rod-shaped body) of about φ10 mm is rotatably supported and the outer peripheral surface of the rod is pressed against the coating layer t1 of the web 2 The excess of the coating material t of the coating layer t1 may be scraped off and removed while rotating the rod.

  As described above, when a round rod-like rod that is rotatably supported instead of the fixed blade 5b is used, the paint t is not clogged between the outer peripheral surface of the rod and the coating layer t1 of the web 2. There is an advantage that it can be used cleanly.

  Here, 3 to 5 times the amount of paint t applied to the web 2 surface by the curtain head 3 is applied to the web 2 surface, and the surplus of the paint t applied to the web 2 using the metering device 5 is applied. It is necessary to scrape off the web 2 in the case of a web having poor coating suitability, a coating having poor coating suitability, or a combination of web and paint having poor coating suitability.

  Thus, by performing the scraping process by the metering device 5, it is possible to obtain a coating performance with a good quality.

  In the case of a good web, a paint with good coating properties, etc., it is only necessary to apply an appropriate amount of paint t to 1 to 2 times on the web 2 surface by the curtain head 3, and scraping off by the metering device 5. There is no need to perform the process.

  By the way, as described above, the web 2 between the transport rolls r5 and r6 is transported at an inclination angle θ ° downward with respect to the web transport direction, as shown in FIGS.

  The inclination angle θ ° is set using the paint flow rate, the paint viscosity, and the like as parameters, and the inventors have obtained the following qualitative and quantitative characteristics.

  Regarding the relationship between the paint viscosity and the web inclination angle θ °, whether the paint t can be uniformly applied to the web 2 by changing the viscosity of the paint t by setting the paint flow rate to 25 liters / minute and the web width of 1 m. Tests were carried out to find the conditions for obtaining the required coating performance.

  When the web inclination angle θ ° is 2 degrees, the coating is uniformly applied if the viscosity of the coating material t is 350 millipascals or more. Further, when the web inclination angle θ ° is 10 degrees, the coating is uniformly performed if the viscosity is 200 millipascals or more. In addition, when the web inclination angle θ ° was 20 degrees, a uniform coating result was obtained as long as the viscosity was 150 millipascals or more.

  That is, in the case of the paint t having a low viscosity, uniform application cannot be performed unless the web inclination angle θ ° is increased. The reason is that when the web inclination angle θ ° is small, the paint t flows out to the upstream side of the web 2 and the paint t is not uniformly applied to the web 2.

  On the other hand, regarding the relationship between the paint flow rate and the web inclination angle θ °, the paint viscosity is set to 250 millipascals, and the paint flow rate is changed to test whether the paint t can be uniformly applied to the web 2. The conditions for obtaining coating performance were found.

  When the web inclination angle θ ° is 2 °, the coating is uniformly applied if the flow rate of the coating material t is 25 (liter / minute · web width 1 m) or less. Further, when the web inclination angle θ ° is 10 degrees, the coating is uniformly performed if the flow rate is 30 (liters / minute / web width of 1 m) or less. Further, when the web inclination angle θ ° is 20 degrees, the coating is uniformly performed if the flow rate is 35 (liter / minute · web width 1 m) or less. In addition, when the web inclination angle θ ° was 40 degrees, a uniform coating was obtained as long as the flow rate was 45 (liters / minute · web width 1 m) or less.

  That is, when the flow rate of the coating material t is large, uniform application cannot be performed unless the inclination angle θ ° of the web 2 is increased. The reason is that when the web inclination angle θ ° is small, the paint t flows out to the upstream side of the web 2 and the paint t is not uniformly applied to the web 2.

  Next, the coating process of the coating material t with respect to the web 2 by the coating apparatus 1 is demonstrated using FIG. 1, FIG.

As shown in FIG. 1, when the web 2 wound around a winder (not shown) is carried in from the web entrance In and conveyed to the curtain head 3, as shown in FIG. The coating material t is applied to the application surface 2n of the web 2 by the coating curtain tc of the coating material t to be formed, and a coating layer t1 is formed.

  The inclination angle θ ° of the web applied by the paint curtain tc is appropriately set according to the coating conditions such as the paint flow rate and the paint viscosity based on the above test.

  Here, in the case of a base paper having poor coating suitability such as a poor coating application surface 2n1 of the web 2 or a paint having poor coating suitability, a larger amount of paint t, for example, 3 to 5 times the amount actually applied. Apply an amount of.

  On the other hand, when the web 2 is a good base paper, a good paint, or the like, an appropriate amount, for example, an amount of the paint t of 1 to 2 times is applied.

  Here, when the web 2 is transported at a speed of about 300 m / min or more, air is applied on the surface of the web 2 to be transported, and the paint curtain tc is disturbed by the wind, so that normal coating can be performed. There may be no cases.

  In this case, as shown in FIG. 2 (a), the air cut device 8 disposed on the upstream side of the coating curtain tc in the web conveyance direction causes the web 2 to be oppositely conveyed in the direction opposite to the application surface 2n of the web 2 ( A high-speed air flow k with a wind speed of 60 to 100 m / sec is blown in the direction of arrow B in FIG. 2A, and air on the application surface 2n of the web 2 to be conveyed is blown away to prevent the paint curtain tc from being disturbed. doing.

  Thereafter, the web 2 to which the coating material t is applied is transported through the transporting rolls r6 and r7 and wound around the backing roll 4, and in the case of a base paper having poor coating suitability or a coating material having poor coating suitability, the meter 2 The blade 5b (or rod) of the ring device 5 is adjusted by the adjusting device 5b1 and appropriately pressed against the coating layer t1 of the web 2 to scrape off and remove the excess of the coating t in the coating layer t1. A predetermined film thickness is obtained.

  In this way, in the case of a base paper with poor coating suitability, a paint with poor coating suitability, etc., a large amount of paint t is applied in advance, and then the extra paint t is scraped off using the metering device 5. The quality of a predetermined coating layer t1 is obtained.

  On the other hand, when the web is a good base paper or a paint t with good coating suitability, it is not necessary to scrape off the excess of the paint t applied using the metering device 5.

  Therefore, the metering device 5 is adjusted by the adjusting device 5b1, and the state in which the blade 5b is separated from the coating layer t1 of the web 2 is maintained, and the paint t is not scraped off.

  Thus, in the case of base paper, paint, etc. with poor coating suitability, a large amount of paint t is applied to the surface of the web 2 and the process of scraping off the paint t by the blade 5b of the metering device 5 is performed. In the case of a fresh base paper, a good paint, etc., only an appropriate amount of the paint t is applied to the paint t on the two web surfaces, and the metering device 5 is adjusted so that the blade 5b is moved from the coating layer t1 of the web 2 The paint t is not scraped away.

  Therefore, the coating apparatus 1 can cope with various combinations of base paper and paint.

  In this way, the web 2 on which the coating layer t1 having a predetermined thickness is formed, as shown in FIG. 1, is directed to a line where a drier (not shown) is provided in order to dry the applied paint t. It is conveyed to the web exit Ot and a drying process is performed.

  According to the above configuration, when the web 2 is a good quality base paper, a good quality paint, or the like, only the paint t is applied by the paint curtain tc of the curtain head 3.

  On the other hand, when the web 2 is a base paper having poor coating suitability, and the paint t has poor coating suitability, the web 2 is applied to the web 2 by the blade 5b of the metering device 5 after application of a large amount of paint t by the paint curtain tc of the curtain head 3. The applied coating material t is scraped off to obtain a coating layer t1 having a predetermined thickness, thereby obtaining a predetermined quality.

  Therefore, the smoothness of the surface of the coating layer t1 of the web 2 and the adhesion of the paint t to the web 2 are improved with respect to combinations of various types of base paper and various types of paint t.

  Therefore, it is possible to deal with combinations of various types of base paper and various types of paints t, and the coating suitability is wide.

  In this way, according to the coating conditions, the process of applying only the paint t, or the process of applying the paint t and the process of scraping off the excess paint are selected. The coating accuracy is high.

  Further, since the curtain head 3 for applying the coating material t to the web 2 blows the coating material t downward, the coating material t is prevented from adhering to the nozzle 3n, the blowout portion and the like of the curtain head 3, and is difficult to get dirty. Easy to clean.

    Moreover, since the direction in which the coating material t is blown out from the curtain head 3 is downward and gravitational acceleration is applied, the total amount of the coating material t used for application of the web 2 can be reduced to 1 to 3 times the applied amount.

  In addition, since the web 2 is conveyed by being inclined and inclined downward at a predetermined inclination angle according to conditions such as the viscosity and flow rate of the coating material t, the coating material t can be applied uniformly.

  Therefore, a more excellent coating apparatus 1 can be realized while taking advantage of the features of the blade coater and the curtain coater.

  As an application example of the present invention, a magnetic material is applied to one side of a ticket for an automatic ticket gate in addition to a coating apparatus for applying paint to a calendar, catalog, thermal paper, pressure-sensitive paper (carbonless paper), etc. Therefore, it can be applied to a coating apparatus or the like.

The conceptual front view containing the partial cross section which shows the coating apparatus of an Example. (a) And (b) is a notional front sectional view and a right side view showing around the curtain head portion of the coating apparatus of the embodiment. The conceptual front sectional drawing which shows the conventional blade metering.

Explanation of symbols

1 ... Coating device,
2 ... Web,
2n: Planned application surface,
3 ... Curtain head (application means),
4 ... backing roll,
5 ... Metering device (paint scraping means),
5b ... blade (scraping member),
8 ... Air cut device,
t ... Paint,
t1 ... coating layer,
tc ... Paint curtain,
θ: Inclination angle.

Claims (3)

A coating apparatus for applying a paint on a web surface while conveying a web,
A web to which a coating is applied by being conveyed at a predetermined inclination angle toward the lower side;
A coating means for spraying paint from above toward the web surface to form a paint curtain, and applying a paint on the web surface to form a coating layer;
It is arranged downstream of the coating means in the web conveyance direction, scrapes off the scraping member from below toward the coating layer of the web wound around the backing roll, and scrapes the excess paint in the coating layer of the web A coating apparatus comprising: paint scraping means for dropping. The scraping member of the paint scraping means is a rotatable round bar-like body whose outer peripheral surface is pressed against the coating layer of the web and scrapes off excess paint in the coating layer of the web while rotating. The coating apparatus according to claim 1. An air cut device that is disposed upstream of the paint curtain in the web conveyance direction and blows a high-speed air stream toward the web in the anti-conveyance direction with respect to the coating application surface of the web to be conveyed;
The coating according to claim 1, wherein the coating curtain is prevented from being disturbed by blowing off air on a planned application surface of the web conveyed by a high-speed air flow of the air-cut device. apparatus.

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