JP2007216161A - Coating work method for applying high gloss coating onto printed paper - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a coating work method by which high gloss coating is applied onto a printed matter simultaneously with printing in a short period of time in a single step by eliminating various defects in gloss coating. <P>SOLUTION: As a method of pressure-fixing and curing a coating composition in-line, an apparatus is provided which comprises transparent cylinders each having an ultraviolet lamp mounted inside and a surface energy of ≤30 mN/m and impression cylinders, and curing and press work are simultaneously applied to the printed matter when passing between the cylinders, thus high gloss coating work is applied to the printed matter. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a method of forming a highly glossy coating film on a printed material, and more specifically, conventionally, an aqueous coating composition is applied to various printed materials off-line, and mirror gloss processing is performed by means such as an endless press. The present invention relates to a technique for obtaining a high-gloss coating processed printed matter in one pass by simultaneously applying pressure and drying after in-line application of an ultraviolet curable coating composition simultaneously with lithographic printing.

    A method of applying a high-gloss finish by applying a water-based coating composition to the surface of a printed material made of paper, followed by heating and drying, followed by applying a mirror-finished heating roller, is called an endless press. is there. Although this method has an advantage that a printed matter having a specular gloss can be obtained, the printing process and the gloss processing process cannot be performed at the same time, and it generally takes several days to complete. In addition, the endless press and the apparatus must be individually held, and a short delivery time and a small lot size printed matter could not be obtained at a low cost in a short time.

  In recent years, UV curable coating varnishes have been applied in-line and simultaneously with lithographic printing, but they can be glossed in a short time. In order to harden and form a film, the above-described aqueous coating and the mirror-less gloss developed by endless press processing are not reached, and the coating material is also expensive and expensive compared to the aqueous endless press.

  Furthermore, a technique for obtaining a mirror gloss equivalent to an endless press has been developed by applying an ultraviolet curable coating composition off-line and then bringing a polypropylene film or the like into close contact and curing, followed by peeling off the polypropylene film. However, in this method, printing and gloss processing are separate processes, and printing and surface processing cannot be performed in a short time in one process.

In addition, a method of applying a high gloss coating to the printed matter by constructing the coating blanket and cylinder material with a smooth and non-adhesive low-energy surface has been proposed, but in reality, the gloss becomes so high that endless press processing is performed. Is not done.
Special table 2003-507204 gazette

    An object of the present invention is to provide a system capable of eliminating the above-mentioned drawbacks in the gloss coating process and economically applying a high gloss coating to a printed material in a single step in a short time simultaneously with printing.

That is, the present invention provides a transparent cylindrical cylinder having a surface energy of 30 mN / m or less with an ultraviolet lamp installed therein as a method for press-curing the coating composition in-line following lithographic printing and coating agent coating in a lithographic printing machine. There is provided a coating processing method for performing high gloss coated printed matter processing, characterized by having a device composed of an impression cylinder and performing press processing simultaneously with curing when a coated printed matter passes between cylinders.
The present invention also provides a coating method for performing high gloss coated printed matter processing, wherein the printing ink and coating composition used in the present invention are ultraviolet curable materials.

    According to the coating processing method for processing a high gloss coated printed material according to the present invention, it is possible to perform printing and coating in one step without the need for an endless press apparatus conventionally performed off-line by incorporating it in a printing machine with a coater. It is possible to obtain a specular gloss coating printed material economically in a short time. In addition, the conventional UV curable coating composition is generally higher in gloss than the aqueous coating composition, but cannot be subjected to endless press processing and cannot be used to process a mirror glossy coated printed product. Mirror gloss processing can be performed using UV curable coating.

    In general, printing and coating processes in a lithographic printing press having a coating apparatus are completed through a four-color printing in a printing unit and then a varnish in a coating apparatus as shown in FIG. The system of the present invention follows exactly the same process as the conventional system up to four-color printing and coating by a coating apparatus, but in the process of drying the coating composition, pressure is applied with two cylinders as shown in FIG. At the same time, the coating agent applied to the printed material is dried to smoothen the coating surface and develop a mirror gloss.

    As a method of simultaneously applying pressure and drying in two cylinders after coating the coating composition, pressure and drying are performed when passing between the nips of the two cylinders, but the coating composition is applied. The cylinder (A) in contact with the coated surface must be transparent. On the other hand, the cylinder (B) in contact with the surface not coated with the coating composition does not have to be particularly transparent.

    The material of the cylinder (A) is preferably a material that efficiently transmits ultraviolet rays, and plastic resins such as quartz, polyolefin, polystyrene, PET, hard PVC, and acrylic can be used. Further, considering the adhesion of the coating composition before drying and the peelability after drying, the energy of the cylinder (A) surface is preferably 30 mN / m or less. For this purpose, it is also effective to apply a silicon material such as polysiloxane to the cylinder surface. Further, in order to develop a specular gloss, the surface average roughness Ra is preferably 3 μm or less.

    As a material of the cylinder (B), it is possible to apply a blanket cylinder generally used in a lithographic printing machine, and a blanket having various rubber materials used as a surface for the blanket cylinder can be used, and the Shore hardness is 70 or more. preferable.

    The printing pressure between the cylinders (A) and (B) is preferably 0.1 to 10 MPa. Normally, an offline endless press applies a pressure of several tens of MPa, but the mirror-finished method according to the present invention is also characterized in that the coating composition presses the state before drying, so that no pressure is required by the conventional method. A desired gloss can be obtained by applying a minimum printing pressure according to the thickness of the printing paper or the like.

  In addition, an ultraviolet lamp is built in the cylinder (A), and pressure is applied between the cylinders by the ultraviolet light, and at the same time, the coating composition is cured and dried. As the ultraviolet lamp, a mercury lamp, a metal halide lamp or the like can be used. In addition, an air-cooled or water-cooled cooling device is provided as necessary. The ultraviolet light emitted from the ultraviolet irradiation lamp needs to be irradiated toward the nip between the cylinders (A) and (B), and it is necessary to shield the ultraviolet rays from diffusing in the other directions.

    By forming the printing ink and coating composition used in the present system with an ultraviolet curable material, it is possible to efficiently obtain a coated printing portion having a specular gloss in one step. UV curable materials include non-reactive resins (inert resins), radical polymerizable oligomers, radical polymerizable monomers, radical polymerization initiators, photosensitizers, pigments, and various additives as necessary. . For example, a hybrid ink having both ultraviolet curing and oxidation polymerization can be used as the printing ink, and the printing ink can also be applied as a combination of a conventional oxidation polymerization type ink and an ultraviolet curing coating composition.

Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings.
FIG. 2 shows a schematic configuration of a lithographic printing machine equipped with a high gloss coating system.
In this system, when UV curable ink is used after printing at the printing unit (1), the ink is cured by the drying unit (2), and then the printing surface is coated and pressurized by the coating unit (3). -When passing between cylinders (A) and (B) in a drying unit, the coating surface is pressurized and smoothed, and at the same time, the coating composition is cured with an ultraviolet lamp.

    FIG. 3 is a side sectional view of one embodiment of the cylinder (A), and the cylinder is fixed by a shaft (8) connected to the printing press. The transparent cylinder part rotates about a shaft (8) fixed via a bearing (9). The cylinder (A) can be rotated in conjunction with the cylinder (B) by the printing pressure with the cylinder (B), and the cylinder (A) can be rotated by connecting a gear and a motor. . Further, by providing a light-shielding plate (7) that shields ultraviolet light from the lamp house (6), the coating composition is prevented from being cured and dried before passing between the cylinders (A) and (B). Further, air holes and fans are provided on the side surfaces of the cylinder (A), respectively, and outside air is sucked and exhausted by the fans to cool the exhaust lamp house (6).

    FIG. 4 is a cross-sectional view of an embodiment of the cylinder (A) part. One of the fans installed on both side surfaces is for intake of outside air, and the other is for discharge of outside air. Air-cool the house (6). Moreover, the shaft (8) of the cylinder (A) has a hollow structure, and the temperature of the lamp house is indirectly increased by cooling the reflecting plate portion of the lamp house installed in the shaft by circulating cooling water inside. Suppress control.

    As an alternative to an endless press using a conventional aqueous coating composition, the present invention applies a UV curable coating composition to a printed product off-line, and simultaneously performs pressure and drying consisting of two cylinders of the system to produce a mirror surface. It is also possible to obtain a specified high gloss coating composition.

The drawing which showed schematic structure of the lithographic printing machine provided with the existing coating apparatus. BRIEF DESCRIPTION OF THE DRAWINGS Drawing which showed schematic structure of the lithographic printing machine provided with the high gloss coating system of this invention. Side sectional view of cylinder (A) Cross section of cylinder (A)

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Printing unit 2 Ultraviolet drying unit 3 Coating unit 4 Pressurization and drying unit of the present invention 5 Fan 6 Ultraviolet lamp house 7 Shading plate 8 Shaft 9 Bearing A Transparent cylinder (A) of the present invention
B Cylinder of the present invention (B)

Claims (2)

  In a lithographic printing machine, as a method of press-curing the coating composition in-line following lithographic printing and coating agent coating, a transparent cylindrical cylinder and an impression cylinder with an ultraviolet lamp inside and a surface energy of 30 mN / m or less A coating processing method for processing a high-gloss coated printed material, characterized in that it has an apparatus comprising cylinders and presses simultaneously with curing when the coated printed material passes between the cylinders. 2. The coating processing method for applying a high gloss coated coating product according to claim 1, wherein the printing ink and the coating composition are ultraviolet curable materials.

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