JP2012066227A - Gravure coater - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a gravure coater preventing a problem of abrasion of a gravure cylinder printing plate and a doctor caused by the frictional rotation due to the contact of the gravure cylinder printing plate with the doctor, and suppressing stepped unevenness caused by vibration during coating and coating unevenness due to a back side of a spatula.SOLUTION: The gravure coater includes the cylindrical gravure cylinder printing plate having a lot of recesses of a fixed shape on an outer circumference, the doctor scraping surplus coating liquid of the cylindrical gravure cylinder printing plate rotated in the coating liquid, and a ceramic flame spraying film layer on the outer circumferential surface of the cylindrical gravure cylinder. At least the surface of the tip part of the doctor is laminated with an organic resin dispersed composite plating layer containing fluororesin particles.

Description

  The present invention relates to a gravure coating apparatus that uniformly applies a coating solution to a web-like substrate that is continuously conveyed. More specifically, the present invention relates to a gravure coating apparatus that does not cause various coating defects caused by contact between a gravure cylinder plate and a doctor generated during coating.

  A gravure coating apparatus is used that can apply a coating liquid to a web-like substrate that is continuously transported, even if it is a coating liquid having a high accuracy and a low viscosity. And since ancient times, it has been used for coating processing of packaging materials, optical films, electronic substrate materials, and the like.

  Normally, when applying a coating liquid to a substrate using a gravure cylinder plate, a dent of a certain shape (usually a dent provided in the gravure gravure cylinder plate is referred to as a cell 108) as shown in FIG. A cylindrical gravure cylinder plate 101 having a large number is used.

  The cylindrical gravure cylinder plate 101 is immersed in the coating liquid 102 in the coating liquid pan 107 and rotated to pump up the coating liquid 102 along the outer circumference in the rotation direction. Further, the excess coating liquid 102 on the cylindrical gravure cylinder plate 101 other than the inside of the cell 108 is scraped off by a doctor 103 made of a steel plate or the like. Then, a method is applied in which the coating liquid 102 in the cell 108 is transferred to the surface of the base material 104 that is pressure-bonded to the cylindrical gravure cylinder plate 101 by the impression roll 105 and applied.

  In addition, the gravure coating apparatus includes a reverse method in which the gravure cylinder plate rotates in a direction opposite to the advancing direction of the web-like substrate, a floating method without a back roll behind the web-like substrate, and as shown in FIG. Floating reverse method 200 and the like are combined.

  As described above, the gravure coating apparatus is coated with a gravure cylinder plate that always contacts a fixed doctor and rotates in a frictional state. For this reason, the wear of gravure cylinder plates and doctors is a major problem.

  Moreover, since the gravure cylinder plate is required to be applied with high precision, a high-definition plate shape must be formed. For this reason, it is manufactured by an advanced processing machine, and the manufacturing cost is expensive. And the life of the gravure cylinder plate and doctor greatly affects the production cost.

  The gravure cylinder plate is usually made of cylindrical mild steel that is relatively easy to process in order to increase the processing accuracy. And the surface hardness is made high by carrying out Cr plating of the surface, and the prevention of wear is aimed at.

  Further, the doctor is generally made of mild steel, and the surface of an elastic thin plate is subjected to Ni-P plating containing SiC particles. And like the gravure cylinder plate, the surface hardness is increased to prevent wear.

  In addition, doctors are usually worn by hardness differences. However, a doctor burr that could not be worn at the back end of the doctor occurs.

A gravure doctor (for example, Patent Document 1) that prevents the occurrence of burr is also known.

  As shown in FIG. 5, the gravure doctor 300 has a resin layer 110 or a hard, non-viscous ceramic layer laminated on the back side of a steel material layer 109 of a steel or stainless steel doctor.

  A doctor blade (for example, Patent Document 2) with improved wear resistance is also known.

  As shown in FIG. 6, the doctor blade 400 has a plate-shaped base 111 made of a material having elasticity, and a wear-resistant layer that is coated on the surface of the base 111 and made of a material harder than the base 111. 112, the spring constant of the doctor blade is 2.5 to 5.0 N / mm, and the wear resistant layer has a Vickers hardness (HV) of 1000 to 3800.

  In addition, vibration may occur due to spin coating while the gravure cylinder plate and doctor are in contact. Then, there may be a coating defect that appears in a streak pattern at periodic intervals in the direction perpendicular to the substrate running direction, called step unevenness, on the coated surface.

  When such vibrations occur, usually, an operating response such as reducing the pressing pressure pressing the doctor on the gravure cylinder plate or changing the contact angle of the doctor is performed.

  However, in many cases, the unevenness of the steps is not resolved. Then, a new doctor is exchanged to check the situation. In this case, there is a problem that it takes time for replacement work, and further, a break-in operation or the like must be performed.

  Furthermore, the problem is not always solved, and the trouble often occurs for a long time.

  In addition, during the coating operation, a phenomenon called “heraura” in which the coating solution rides on the back side of the blade edge of the doctor occurs, and the loaded coating solution accumulates and grows. And the problem which generate | occur | produces a coating | coated nonuniformity has arisen by drying and causing a foreign material trouble, or returning to a gravure cylinder plate irregularly.

  In order to solve the above problem, a method of applying a water repellent to the surface of the doctor can be considered. However, since the doctor always scrapes off, the water-repellent coating film is stripped unevenly, which may cause band-like unevenness on the coated surface.

JP 7-276601 A JP-A-8-197711

  The present invention has been made in view of the above-mentioned conventional problems, and prevents the gravure cylinder plate and the doctor from being worn due to frictional rotation caused by contact between the gravure cylinder plate and the doctor. It is an object to provide a gravure coating apparatus capable of suppressing step unevenness due to vibrations and coating unevenness due to herula.

  In order to solve the above-mentioned problems, the present invention provides a cylindrical gravure cylinder plate having a plurality of dents having a fixed shape on the outer circumference, and a cylindrical gravure rotated in a coating solution. A gravure coating apparatus having a doctor that scrapes off an excess coating liquid of a cylinder plate, having a ceramic sprayed coating layer on the outer circumferential surface of a cylindrical gravure cylinder, and a surface of at least a tip portion of the doctor is a fluororesin A gravure coating apparatus characterized in that it is laminated with an organic resin-dispersed composite plating layer containing particles.

  According to the gravure coating apparatus of the present invention, the life of the gravure cylinder plate and the doctor can be extended.

  In addition, the occurrence of vibration due to contact between the gravure cylinder plate and the doctor can be reduced. Furthermore, it is possible to suppress the occurrence of coating defects called step unevenness or herura.

It is the expansion schematic of the gravure cylinder plate and doctor of the gravure coating apparatus of this invention. It is the schematic for demonstrating the gravure cylinder plate and doctor periphery of the gravure coating apparatus of this invention. It is a figure shown with an outline of an example of the conventional gravure coating device in a section. It is an example of the conventional gravure coating apparatus, and is a figure which shows the outline of a floating reverse system in a cross section. It is a figure which shows an example of the doctor used for the conventional gravure coating apparatus in a cross section. It is a figure which shows an example different from FIG. 5 of the doctor used for the conventional gravure coating apparatus in a cross section.

  The gravure coating apparatus of the present invention will be described in detail below along the embodiments with reference to the drawings. 1 to 2 show an embodiment of the present invention. A mode for carrying out the present invention will be described in detail with reference to the drawings.

  FIG. 1 is an enlarged schematic view of a portion A of the gravure cylinder plate 1 and doctor 2 of the gravure coating apparatus of the present invention shown in FIG.

  In the gravure coating apparatus of the present invention, as shown in FIG. 2, the doctor 2 that comes into contact with the gravure cylinder plate 1 is fixed by a doctor holder 8 in the same manner as the conventional gravure coating apparatus. The doctor pressure or the like is adjusted by the position or angle of the doctor holder 8.

  Further, since the base material of the gravure cylinder plate 1 needs to be precisely engraved, a material with good workability, for example, a cylindrical low carbon steel of about S20C to S30C is preferable, but is not limited thereto. If a precise engraving process is possible, cylindrical carbon steel or stainless steel can be used.

  When applying a coating solution having high acidity, it is preferable to use SUS316 stainless steel for the base material of the gravure cylinder plate.

  A ceramic sprayed coating layer 6 is laminated on the outer circumferential surface of the gravure cylinder plate 1.

The layer thickness of the ceramic sprayed coating layer 6 may be laminated to about 1 to 5 μm. The hardness is 1
What is necessary is just about 000-2000 (HV). As the material, metal oxide ceramics such as alumina, titania, zirconia, and chromium oxide can be used.

  For the doctor 2, cold rolled steel or stainless steel is used as the base material 3. And the organic resin dispersion | distribution composite plating layer 4 containing the uniform fluororesin is laminated | stacked on the outer surface which touches at least the gravure cylinder plate 1 of a doctor. By using cold rolled steel or stainless steel as the base material 3 of the doctor 2, a doctor having elasticity and toughness can be obtained.

  As the organic resin-dispersed composite plating layer 4 containing the fluororesin, for example, a Ni-P-based plating layer in which fine particles of PTFE (polytetrafluoroethylene) are dispersed can be employed. The particle diameter of PTFE may be about 0.5 to 3 μm.

  Coating process using a gravure cylinder plate 1 having a ceramic spray coating layer laminated on the outer circumferential surface and a doctor having an organic resin-dispersed composite plating layer 4 containing a fluororesin on the outer surface of a doctor base material 3 went. As a result, the effect of significantly reducing the frictional resistance value as compared with the conventional combination was confirmed. Furthermore, the continuous coating processing time has improved dramatically.

  In addition, even for the varieties that have had unevenness due to vibration so far and the yield was very bad, the yield was improved by greatly reducing the vibration. Furthermore, it was confirmed that no laura was generated due to the effect of the fluororesin on the surface of the doctor 2.

  The gravure coating apparatus of the present invention is excellent as a coating apparatus capable of reducing the cost and increasing the precision of precision coating of optical films, electronic substrates, food packaging materials, etc., and medical members such as haptic agents, cooling sheets, and adhesive plasters. It can be used in a wide range of fields such as production.

DESCRIPTION OF SYMBOLS 1 ... Gravure cylinder plate 2 ... Doctor 3 ... Doctor base material 4 ... Organic resin dispersion | distribution composite plating layer 6 containing a fluororesin ... Ceramic sprayed coating layer 7 ... Gravure cylinder base material 8 ... Doctor holder

Claims (1)

  A gravure coating apparatus having a cylindrical gravure cylinder plate having a large number of dents of a constant shape on the outer circumference, and a doctor that scrapes off excess coating liquid of the cylindrical gravure cylinder plate rotated in the coating liquid, Gravure coating characterized in that it has a ceramic sprayed coating layer on the outer circumferential surface of a cylindrical gravure cylinder, and the surface of at least the tip of the doctor is laminated with an organic resin dispersed composite plating layer containing fluorine-based resin particles apparatus.

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