JP2005144806A - Gravure printing method and gravure printed matter - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a gravure printing method and gravure printed matter, which can tackle an environmental pollution problem such as air pollution due to an organic solvent. <P>SOLUTION: This gravure printing method has a changing process of surface properties for removing impurities to check the adhesion of an ultraviolet curing type ink from a polyvinyl chloride-based resin base material, a printing process for forming an ultraviolet curing type ink film by gravure printing on the polyvinyl chloride-based resin base material and a curing process for curing the film through the irradiation of ultraviolet rays on the film. In this gravure printed matter, the ultraviolet curing type ink film is formed by gravure printing on the polyvinyl chloride-based resin base material under the condition that the impurities to check the adhesion of the ink are removed from the polyvinyl chloride-based resin base material. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a gravure printing method and a gravure printed matter that can cope with pollution problems.

  Among the various pollution problems that have been highlighted in recent years, there is air pollution due to organic solvents contained in gravure ink for printing on plastic substrates.

  There is gravure printing such as soft packaging materials as printing of plastic base material, but conventional gravure ink is about 75% organic solvent such as toluene and ketone, about 10-20% adhesive agent to plastic base material, Contains about 10-15% of color pigment. About 75% of these organic solvents are released into the atmosphere during the ink drying process. By the way, there are about 350 offices nationwide that perform gravure printing, and the amount of organic solvent-containing ink used there exceeds 150,000 tons per year, which is all released into the atmosphere. Prefectural ordinances have been enacted to rectify this situation, and efforts and control over the release of organic solvents into the atmosphere have become concrete, and this has become a major issue for establishments that conduct gravure printing.

  For this reason, we considered the construction of a plant with a solvent recovery device that recovers the organic solvent released in the drying process, but the organic solvent recovery rate is low and the performance is satisfactory for the cost of the plant construction. In addition, the recovered organic solvent is colored and has a low cost performance because of limited reuse.

  We have also developed printing technology using water-based inks in which the organic solvent of the gravure ink is replaced with water. However, it takes time to dry the ink, so there is a limit to the printing speed, and ink leveling (wetting properties) on plastic substrates ) Was low.

Furthermore, the development of the mold printing technique using the ultraviolet curable resin of the previously proposed molded article made of the ultraviolet curable resin and its manufacturing method (see Patent Document 1) was examined. However, this technique lacks printability. There was a problem.
Japanese Patent Publication No.2-2403

  Therefore, the present invention intends to provide a gravure printing method and a gravure printed matter that can cope with the pollution problem of air pollution by an organic solvent.

In order to solve the above problems, the present invention takes the following technical means.
(1) The gravure printing method of the present invention includes a surface modification step for removing impurities that hinder the adhesion of ultraviolet curable ink from a polyvinyl chloride resin substrate, and gravure printing on the polyvinyl chloride resin substrate. It has the printing process which forms the film of an ultraviolet curable ink, and the hardening process which irradiates and cures an ultraviolet-ray to the said film.

  This gravure printing method includes a printing process for forming a UV curable ink film on a polyvinyl chloride resin substrate by gravure printing, and an organic solvent is irradiated with UV light to the UV curable ink film that is (almost) not used. Although it has a curing step of curing, it is cured by irradiating ultraviolet curable ink with ultraviolet rays to form a film, and an organic solvent is not used and is not released into the atmosphere.

  In addition, the required time is shortened compared to the formation of an ink film by drying using wind in printing using a normal organic solvent-containing ink or water-based ink, and the overall speed of the printing line is improved.

Furthermore, since it has a surface modification step for removing impurities that hinder the adhesion of the UV curable ink from the polyvinyl chloride resin substrate, the wettability (leveling property) of the UV curable ink to the substrate is improved, The finished state of the printed matter and the resistance (fastness) as a printing ink film are good. As a means of surface modification to remove impurities that hinder the adhesion of the ink, physicochemical treatment such as corona discharge treatment and plasma treatment by high voltage electricity, chemical treatment such as primer treatment and solvent treatment, sandblasting and embossing A mechanical (roughening) treatment such as the above can be exemplified, but any surface modification method having printability may be used. Examples of the impurities include substances that have a low molecular weight compared to the molecular weight of the base material, such as lubricants, plasticizers, dispersants, and UV absorbers contained in the base material, and leak to the base material surface over time. Can do.
(2) The curing step may be performed in a nitrogen gas atmosphere.

  If comprised in this way, since nitrogen gas is cold temperature, it is suitable for cooling the printed matter heated up by ultraviolet irradiation. In addition, the oxygen concentration, which is a hindrance to the formation of the printed film, is diluted, and the decrease in the ink curing rate is suppressed, thereby improving the film forming speed and increasing the printing speed. Furthermore, generation of ozone gas during ultraviolet irradiation is suppressed, and the environmental safety of workers is improved.

 (3) Corona discharge treatment may be performed in the surface modification step.

  If comprised in this way, the impurity which inhibits the adhesion of the said ink will be removed by a corona discharge process, and the functional group which improves the adhesiveness with ultraviolet curable ink will be produced | generated on the surface of a polyvinyl chloride resin base material. be able to.

  In addition, even if a spark is blown as a corona discharge treatment is applied to a polyvinyl chloride resin base material (not a solvent type), the ultraviolet curable ink does not ignite, so a surface modification (corona treatment) step and a printing step The curing process can be processed continuously in the same space, and the process is efficient as a series of gravure printing lines.

 (4) The viscosity of the ultraviolet curable ink may be adjusted to about 50 to 300 cps in the printing step.

In the printing process, a low viscosity of about 50 to 300 cps was suitable as the viscosity of the ultraviolet curable ink, and about 100 cps was the optimum printing ink condition. When the viscosity is about 300 cps or less, it can be processed by a rotary method, and the printing speed can be increased. When the viscosity was less than about 50 cps, there was a tendency that the ink was scattered outside the tank and the surroundings were easily contaminated. Here, as a means for adjusting the viscosity of the ultraviolet curable ink to about 50 to 300 cps, the outside of the tank containing the ink is heated with a heater or the like to raise the temperature of the ink to about 60 ° C. to 80 ° C. An example is keeping warm.
(5) In the gravure printed material of the present invention, an ultraviolet curable ink film is formed on a polyvinyl chloride resin substrate by gravure printing, and the polyvinyl chloride resin substrate removes impurities that hinder the adhesion of the ink. It is characterized by being made.

  According to this gravure printed material, a film of ultraviolet curable ink was formed on the polyvinyl chloride resin substrate by gravure printing, so when irradiated with ultraviolet light, the ink was cured and a film was formed, and no organic solvent was used. It is not released into the atmosphere.

  In addition, the required time is shortened and the overall speed of the printing line is further improved as compared with the formation of an ink film by drying using wind in printing using a normal organic solvent-containing ink or water-based ink.

Further, since the polyvinyl chloride resin base material is one from which impurities impeding the adhesion of the ink are removed, the wettability (leveling property) of the ultraviolet curable ink to the base material is improved, and the printed matter is finished. The resistance (fastness) as a state and printing ink film becomes good. As a method of removing (improvement of surface) the impurities that hinder the adhesion of the ink, physicochemical treatment such as corona discharge treatment or plasma treatment by high voltage electricity, chemical treatment such as primer treatment or solvent treatment, sandblasting or embossing A mechanical (roughening) treatment such as processing can be exemplified, but any surface modification method having printability may be used. Examples of the impurities include substances that have a low molecular weight compared to the molecular weight of the base material, such as lubricants, plasticizers, dispersants, and UV absorbers contained in the base material, and leak to the base material surface over time. Can do.
(6) The polyvinyl chloride resin substrate may be subjected to corona discharge treatment.

  If comprised in this way, the impurity which inhibits the adhesion of the said ink will be removed by a corona discharge process, and the functional group which improves the adhesiveness with ultraviolet curable ink will be produced | generated on the surface of a polyvinyl chloride resin base material. be able to. In addition, it is possible to form a coating film of an ultraviolet curable ink that is not originally very good in gravure printing properties on a polyvinyl chloride resin substrate.

  The present invention is configured as described above and has the following effects.

  Since the organic solvent is not used and is not released into the atmosphere, it is possible to provide a gravure printing method and a gravure printed matter that can cope with the pollution problem of air pollution by the organic solvent.

  Embodiments of the present invention will be described below.

  The gravure printing method of this embodiment includes a surface modification step for removing impurities that hinder the adhesion of UV curable ink from a polyvinyl chloride resin substrate, and UV curing by gravure printing on the polyvinyl chloride resin substrate. A printing process for forming a film of mold ink, and a curing process for curing the film by irradiating with ultraviolet rays.

  The gravure printing is one of intaglio printing by photoengraving, and is a printing method that reproduces the color density of the original image according to the depth of the intaglio depressions and the size of the halftone dots. In this method, excess ink is scraped off with a thin blade (doctor), the ink is filled in the recess, and the filled ink is transferred to the printing substrate. Since this printing method is excellent in tone expression, it is suitably used for reproduction of photographs and fine arts, printing on films and sheets, and is particularly suitable for mass printing by the rotary method.

  Examples of the shape of the polyvinyl chloride resin substrate include a film shape, a plate shape, a spherical shape, and a curved surface shape, and any shape having gravure printability may be used.

  The ultraviolet curable ink refers to an ink formed by a resin that is cured by irradiating ultraviolet rays, and is formed by a synthetic resin such as acrylic or acrylic / urethane, or an organic pigment or inorganic pigment used as necessary. It is composed of a mixture of additives such as an agent, a dispersant and a wetting agent, and is prepared to have a low viscosity.

  Examples of the printed materials include table cloths, curtains, shower curtains, place mats, wallpaper, window stickers, packaging materials, bags, etc., nameplates, company mark boards, information boards ("used", "cleaning" "In a meeting", etc., and other various boards, display objects for product display at supermarkets and retail stores, product information boards, price tags, cover of notebooks, beverage bottles such as bottles, signboards, tableware, etc. it can.

  This gravure printing method includes a printing process for forming a UV curable ink film on a polyvinyl chloride resin substrate by gravure printing, and an organic solvent is irradiated with UV light to the UV curable ink film that is (almost) not used. It has a curing process that cures, but when it is irradiated with ultraviolet rays, it cures instantly and forms a coating, and no organic solvent is used and does not release into the atmosphere. There is an advantage that it is possible to deal with the pollution problem of air pollution by organic solvents.

  In addition, there is an advantage that the required time is shortened and the overall speed of the printing line is improved as compared with the ink film formation by drying using wind in printing using a normal organic solvent-containing ink or water-based ink.

  Furthermore, since it has a surface modification step for removing impurities that hinder the adhesion of the UV curable ink from the polyvinyl chloride resin substrate, the wettability (leveling property) of the UV curable ink to the substrate is improved, There is an advantage that the finished state of the printed matter and the resistance (fastness) as a printing ink film are improved.

  As a means of surface modification to remove impurities that hinder the adhesion of the ink, physicochemical treatment such as corona discharge treatment and plasma treatment by high voltage electricity, chemical treatment such as primer treatment and solvent treatment, sandblasting and embossing A mechanical (roughening) treatment such as the above can be exemplified, but any surface modification method having printability may be used. Examples of the impurities include substances that have a low molecular weight compared to the molecular weight of the base material, such as lubricants, plasticizers, dispersants, and UV absorbers contained in the base material, and leak to the base material surface over time. Can do.

  Here, if impurities that inhibit the adhesion of the ink are removed by corona discharge treatment in the surface modification step, the surface of the polyvinyl chloride resin substrate is simultaneously coated with ultraviolet curable ink by the corona discharge treatment. Functional groups that improve adhesion can be generated. In addition, even if a spark is blown as a corona discharge treatment is applied to a polyvinyl chloride resin base material (not a solvent type), the ultraviolet curable ink does not ignite, so a surface modification (corona treatment) step and a printing step The curing process can be processed continuously in the same space, and there is an advantage that it is efficient as a series of gravure printing lines without stagnation of the process.

  The curing step is performed in a nitrogen gas atmosphere. Since the nitrogen gas has a low temperature, there is an advantage that it is suitable for cooling a printed material that has been heated by ultraviolet irradiation. In addition, there is an advantage that the film formation speed is improved and the printing speed is increased by diluting the oxygen concentration which becomes an inhibiting factor for the formation of the printed film and suppressing the decrease in the ink curing speed. Furthermore, there is an advantage that generation of ozone gas at the time of ultraviolet irradiation is suppressed and the environmental safety of the worker is improved.

  In the printing process, the viscosity of the ultraviolet curable ink is adjusted to about 50 to 300 cps, but such a low viscosity is suitable, and about 100 cps is the optimum printing ink condition. When the viscosity is about 300 cps or less, there is an advantage that it can be processed by a rotary method and the printing speed can be increased. When the viscosity was less than about 50 cps, there was a tendency that the ink was scattered outside the tank and the surroundings were easily contaminated. Here, as a means for adjusting the viscosity of the ultraviolet curable ink to about 50 to 300 cps, the outside of the tank containing the ink is heated with a heater or the like to raise the temperature of the ink to about 60 ° C. to 80 ° C. An example is keeping warm.

  In the gravure printed material of this embodiment, an ultraviolet curable ink film is formed on a polyvinyl chloride resin substrate by gravure printing, and the polyvinyl chloride resin substrate is free of impurities that hinder the adhesion of the ink. Is.

  According to this gravure printed matter, a film of ultraviolet curable ink was formed on the polyvinyl chloride resin substrate by gravure printing, so when irradiated with ultraviolet light, the ink was instantly cured and a film was formed, and an organic solvent was used. It is not released into the atmosphere and has the advantage of being able to deal with the pollution problem of air pollution by organic solvents.

  In addition, there is an advantage that the required time is shortened and the entire speed of the printing line is further improved as compared with the ink film formation by drying using wind in printing using a normal organic solvent-containing ink or water-based ink.

  Further, since the polyvinyl chloride resin base material is one from which impurities impeding the adhesion of the ink are removed, the wettability (leveling property) of the ultraviolet curable ink to the base material is improved, and the printed matter is finished. There is an advantage that resistance (fastness) as a state or printing ink film is improved.

  Here, assuming that the impurities that hinder the adhesion of the ink are removed by corona discharge treatment, a functional group that improves the adhesion to the ultraviolet curable ink is generated on the surface of the polyvinyl chloride resin substrate at the same time. Can be. In addition, it is possible to form a coating film of an ultraviolet curable ink that is not originally very good in gravure printing properties on a polyvinyl chloride resin substrate.

  In this embodiment, a pattern or a pattern is printed on one surface of a polyvinyl chloride resin substrate using a low-viscosity UV curable ink on a rotary gravure printing machine, and then to the printing ink surface of the substrate. The process of forming a printed film by irradiating with ultraviolet rays was continuously performed several times to obtain a multicolored gravure print.

  The surface of the base material is subjected to surface modification by high-voltage corona discharge treatment. This corona discharge treatment reduces the molecular weight of the base material such as lubricants, plasticizers, dispersants, ultraviolet absorbers, etc., which inhibit the adhesion of the ink. Substances leaking to the surface could be removed or eliminated. Moreover, the functional group which improves the adhesiveness with ultraviolet curable ink was able to be produced | generated to the surface of the polyvinyl chloride-type resin base material simultaneously by the said corona discharge process.

  The viscosity of the ultraviolet curable ink was adjusted to a low viscosity of about 50 to 300 cps. The viscosity can be adjusted by heating the outside of the tank containing the printing ink with a heater and raising the temperature of the printing ink to about 60 to 80 ° C. and keeping it warm.

  Since this gravure print uses ultraviolet curable ink and can produce a gravure print without using an organic solvent, it can greatly contribute to environmental protection problems through reduction of air pollution by the organic solvent.

  In addition, since the printing ink is cured and a film is formed instantly when irradiated with ultraviolet rays, the time required is shortened compared to film formation by drying using wind in printing using ordinary organic solvent-containing ink or water-based ink. The overall speed of the printing line has been improved.

  Furthermore, the process of irradiating ultraviolet rays is performed in an atmosphere filled with nitrogen gas. Oxygen that inhibits the formation of the printed film is expelled from the working atmosphere, and the oxygen concentration is diluted to reduce the ink curing rate. Therefore, the film forming speed is improved and the printing speed is increased. Moreover, generation | occurrence | production of the ozone which arises by the chemical reaction to oxygen by ultraviolet irradiation is suppressed, and it can contribute to the improvement of a working environment.

  In this example, after a pattern or pattern is continuously printed several times as in Example 1, a topcoat agent having transparency formed by an ultraviolet curable resin is further applied and cured by irradiation with ultraviolet rays. To form a transparent layer.

  Since the surface of this gravure printed material is coated with a transparent layer of a topcoat agent, it is possible to protect a pattern, a pattern and the like, and there is an advantage that the fastness of the printing ink film is improved.

  The printed materials of Examples 1 and 2 are materials such as table cloths, curtains, shower curtains, place mats, wallpaper, window stickers, packaging materials, bags, etc., name plates, company mark boards, information boards ( ”“ Cleaning ”“ Meeting ”, etc., other various boards, display items for product display at supermarkets and retail stores, product information boards, price tags, cover of notebooks, beverage bottles such as bottles, signboards, tableware For example, it can be suitably used.

Since organic solvents are not used and are not released into the atmosphere, it is possible to address the pollution problem of air pollution caused by organic solvents, and UV-curable ink coatings can be applied to polyvinyl chloride resin substrates by gravure printing. It can apply suitably for the use to form.

Claims (6)

A surface modification process for removing impurities that hinder the adhesion of UV curable ink from a polyvinyl chloride resin substrate, and a printing process for forming a UV curable ink film on the polyvinyl chloride resin substrate by gravure printing. And a curing step of irradiating the coating with ultraviolet rays to cure the gravure printing method. The gravure printing method according to claim 1, wherein the curing step is performed in a nitrogen gas atmosphere. The gravure printing method according to claim 1 or 2, wherein a corona discharge treatment is performed in the surface modification step. The gravure printing method according to claim 1, wherein the viscosity of the ultraviolet curable ink is adjusted to about 50 to 300 cps in the printing step. An ultraviolet curable ink film is formed on a polyvinyl chloride resin substrate by gravure printing, and the polyvinyl chloride resin substrate is obtained by removing impurities that inhibit the adhesion of the ink. Gravure print. The gravure printed matter according to claim 5, wherein the polyvinyl chloride resin substrate is subjected to corona discharge treatment.