JP7571568B2 - Printing film and processing method thereof, printed matter and manufacturing method thereof - Google Patents

Description

The present invention relates to a printed film formed using a printing ink containing antibacterial and antiviral metal particles or metal oxide particles and a binder resin, and in particular to a printed film in which part of the surface of the metal particles or metal oxide particles present on or near the printed film surface is exposed, a processing method thereof, and a printed matter and a manufacturing method thereof.

Copper, silver, nickel, and zinc have long been known to have antibacterial and antiviral properties. Among these, copper and silver have extremely high antibacterial and antiviral properties, and are used in everyday items such as sink corners, washbasins, and doorknobs. The antibacterial and antiviral properties are thought to be due to the active oxygen generated by the reaction of metal with the surrounding moisture, or trace amounts of metal ions dissolved in the moisture, which inhibit the growth of bacteria and inactivate viruses, or due to contact with the solid metal surface.

In particular, it has been demonstrated that the antibacterial and antiviral effects of copper-containing compounds are due to contact with solid metal surfaces, and the U.S. Environmental Protection Agency (EPC) approved the antibacterial effects of copper in 2008, drawing even more attention to the antibacterial and antiviral effects of copper.

Currently, in addition to products made by pressing drawn copper products, there are a wide variety of uses for copper, including coating the surface of an article with copper or attaching copper foil, incorporating copper particles into fibers or films, or printing copper particles on paper or cloth.

Patent Document 1 discloses an antibacterial and antiviral member that is composed of a cuprous oxide particle dispersion that contains cuprous oxide particles, a coating composition that contains the dispersion and a binder resin, and a substrate and a coating of the coating composition provided on the substrate.

International Publication No. 2014/132606 (see claims 1 to 3, paragraph 0039)

However, when a coating of a coating composition containing antibacterial and antiviral metal particles or metal oxide particles and a binder resin is formed on a substrate to produce the antibacterial and antiviral member described in Patent Document 1, even if metal particles or metal oxide particles are present on or near the coating surface, the surfaces of these particles may be covered with the coating.

As a result, the antibacterial and antiviral effects of metal particles and metal oxide particles can be suppressed by the coating of the coating composition.

The present invention was made with a focus on these problems, and its objective is to provide a printed film formed using a printing ink containing antibacterial and antiviral metal particles or metal oxide particles and a binder resin, in which the antibacterial and antiviral effects of the metal particles or metal oxide particles are fully exerted, a processing method for the printed film, and a printed matter in which the printed film is formed on the surface of a substrate, and a manufacturing method for the printed matter.

In order to solve the above problems, the present inventor irradiated the surface of a printed film formed using a printing ink containing antibacterial and antiviral metal particles or metal oxide particles and a binder resin with atmospheric pressure plasma and confirmed the effect. He discovered that the resin components of the printed film covering the surfaces of the metal particles or metal oxide particles present on or near the surface of the printed film were uniformly removed, and the antibacterial and antiviral effects of the metal particles or metal oxide particles were fully exerted. The present invention was completed based on such technical discoveries.

That is, the first invention according to the present invention is,
A printing film formed by using a printing ink containing antibacterial and antiviral metal particles or metal oxide particles and a binder resin,
a part of the surface of a part of metal particles or metal oxide particles contained in the printing film is exposed on or near the surface of the printing film ;
The printed film has a thickness of 0.5 μm to 100 μm, and the median value of the particle size distribution of the metal particles or metal oxide particles is ⅓ or less of the film thickness .

The second aspect of the present invention is
In the printing film according to the first aspect of the present invention,
The antibacterial and antiviral metal particles are characterized in that they are composed of any one of copper particles, silver particles, nickel particles, and zinc particles;
The third invention is
In the printing film according to the first aspect of the present invention,
The antibacterial and antiviral metal oxide particles are characterized by being composed of cuprous oxide particles,
The fourth invention is
A printing film formed using a printing ink containing antibacterial and antiviral metal oxide particles and a binder resin,
a part of the surface of an oxide particle of a part of a metal contained in the printing film is exposed on or near the surface of the printing film;
The antibacterial and antiviral metal oxide particles are characterized in that they are composed of cuprous oxide particles,
The fifth invention is
In print,
The printed film according to any one of the first to fourth aspects of the present invention is formed on a surface of a substrate,
The sixth invention is
In the printed matter according to the fifth aspect of the present invention,
The substrate is characterized in that it is made of any one of paper, wood bark, cloth, plastic plate, metal plate, ceramic plate, and glass plate.

Next, the seventh invention is
In a method for producing a printed matter,
A printing step of printing ink containing antibacterial and antiviral metal particles or metal oxide particles and a binder resin on a surface of a substrate to form a coating of the printing ink;
a curing step of applying active energy rays to the coating to cure it and form a printed cured film;
an atmospheric pressure plasma treatment step of irradiating the surface of the printed cured film with atmospheric pressure plasma to remove the binder resin covering the surfaces of metal particles or metal oxide particles present on or in the vicinity of the surface of the printed cured film, thereby exposing a portion of the surfaces of the metal particles or metal oxide particles;
The present invention is characterized in that
The eighth invention is
In the method for producing a printed matter according to the seventh aspect of the present invention,
The process gas used in the atmospheric pressure plasma treatment step is mainly composed of nitrogen, argon gas, or helium, and one or more active species selected from oxygen, nitrogen, hydrogen, water, and ammonia are added to the process gas;
The ninth invention is
In the method for producing a printed matter according to the seventh or eighth invention,
In the atmospheric pressure plasma treatment step, an active species activated by a remote atmospheric pressure plasma generator is irradiated onto the surface of the printed cured film,
The tenth invention is
In the method for producing a printed matter according to any one of the seventh to ninth aspects of the present invention,
The antibacterial and antiviral metal particles used in the printing process are composed of any one of copper particles, silver particles, nickel particles, and zinc particles,
The eleventh invention is
In the method for producing a printed matter according to any one of the seventh to tenth aspects of the present invention,
the binder resin used in the printing step is composed of a rosin-modified phenolic resin and the antibacterial and antiviral metal particles are composed of copper particles, the process gas used in the atmospheric pressure plasma treatment step is argon gas to which a mixed gas of 10% oxygen and 4% hydrogen is added, and a power of 50 W to 100 W is applied from a high-frequency power source to an atmospheric pressure plasma head of a remote type atmospheric pressure plasma generator, so that the printed cured film of the substrate transported at a speed of 30 m/min to 60 m/min is irradiated with atmospheric pressure plasma,
The twelfth invention is
In the method for producing a printed matter according to any one of the seventh to ninth aspects of the present invention,
The antibacterial and antiviral metal oxide particles used in the printing process are characterized by being composed of cuprous oxide particles,
The thirteenth invention is
In the method for producing a printed matter according to any one of the seventh to twelfth aspects of the present invention,
The substrate is made of any one of paper, wood bark, cloth, plastic plate, metal plate, ceramic plate, and glass plate,
In addition, the fourteenth invention is
A method for treating a printed film formed by using a printing ink containing antibacterial and antiviral cuprous oxide particles and a binder resin, the surface of a part of the cuprous oxide particles being exposed from the surface of the printed film, comprising:
The method is characterized in that the surface of the cuprous oxide particles exposed from the surface of the printed film is irradiated with atmospheric pressure plasma to reduce a portion of the oxidized copper oxide to cuprous oxide, thereby activating the antibacterial and antiviral properties of the cuprous oxide particles.

According to the printing film of the present invention, which is formed using a printing ink containing antibacterial and antiviral metal particles or metal oxide particles and a binder resin,
Since a portion of the surface of some of the metal particles or metal oxide particles contained in the printed film is exposed on or near the surface of the printed film, it is possible to fully exert the antibacterial and antiviral effects of the metal particles or metal oxide particles.

In addition, according to the method for producing a printed matter according to the present invention, in which a printed film is formed on a surface of a substrate,
In the atmospheric pressure plasma treatment step, the surface of the printed cured film is irradiated with atmospheric pressure plasma to remove the binder resin covering the surfaces of metal particles or metal oxide particles present on or near the surface of the printed cured film, thereby exposing part of the surfaces of the metal particles or metal oxide particles, making it possible to produce printed items in which the antibacterial and antiviral effects of the metal particles or metal oxide particles are fully exerted.

Furthermore, according to the method for treating a printed film according to the present invention, the metal oxide particles are composed of cuprous oxide particles, and the surfaces of some of the cuprous oxide particles are exposed from the surface of the printed film,
By irradiating the surfaces of the cuprous oxide particles exposed from the printed film surface with atmospheric pressure plasma, a portion of the oxidized copper oxide is reduced to cuprous oxide, thereby activating the antibacterial and antiviral properties of the cuprous oxide particles.

FIG. 1 is an explanatory diagram of an apparatus according to a first embodiment used in a method for producing a printed matter according to the present invention. FIG. 5 is an explanatory diagram of an apparatus according to a second embodiment used in the method for producing a printed matter according to the present invention. FIG. 3(A) is an explanatory diagram relating to the manufacturing method of the above-mentioned printed matter; FIG. 3(A) is an explanatory cross-sectional view of a coating immediately after printing the printing ink of the present invention on the surface of a substrate; FIG. 3(B) is an explanatory cross-sectional view of a printed cured film formed by hardening the above-mentioned coating after drying; and FIG. 3(C) is an explanatory cross-sectional view showing the state in which the surfaces of metal particles or metal oxide particles present on the surface of the above-mentioned printed cured film have been exposed by removing the binder resin covering the surfaces of metal particles or metal oxide particles.

The following describes an embodiment of the present invention in detail with reference to the drawings.

[Printed film]
(1) Printed film The printed film according to the present invention is formed using a printing ink containing antibacterial and antiviral metal particles or metal oxide particles and a binder resin.
The printed film is characterized in that a portion of the surfaces of metal particles or metal oxide particles contained in the printed film is exposed on or near the surface of the printed film.

The antibacterial and antiviral effects of metal particles and metal oxide particles are thought to be due to the fact that, as mentioned above, active oxygen generated by the reaction of metal with surrounding moisture or trace amounts of metal ions dissolved in the moisture inhibit the growth of bacteria and inactivate viruses, or due to contact with the solid metal surface.

However, in a printed film (printed cured film) formed using a printing ink containing metal particles or metal oxide particles and a binder resin, even if metal particles or metal oxide particles are present on or near the surface of the printed film (printed cured film), if the surfaces of these particles are covered with the binder resin, metal ions are unlikely to dissolve from the metal particles, and antibacterial and antiviral effects are unlikely to be exhibited.

The present invention is characterized in that the surface of the printed cured film is irradiated with atmospheric pressure plasma to remove the binder resin covering the surfaces of the metal particles or metal oxide particles present on or near the surface of the printed cured film, allowing the antibacterial and antiviral effects of the metal particles and metal oxide particles to be fully exerted.

In other words, metal particles or metal oxide particles with part of their surface exposed to the air generate minute amounts of metal ions, enabling them to fully exert their antibacterial and antiviral effects.

In any of the mechanisms related to the antibacterial and antiviral effects described above, it is clear that in order to effectively exert the antibacterial and antiviral effects, it is preferable for the metal surface to be exposed to the atmosphere.

(2) Metal particles, metal oxide particles, and film thickness of printed film (2-1) The metal particles to be applied are preferably composed of any one of copper particles, silver particles, nickel particles, and zinc particles. These metal particles have antibacterial and antiviral properties, and are inexpensively available. These metal foils, plates, and plating films have antibacterial and antiviral properties. In addition, the metal oxide particles to be applied are preferably composed of cuprous oxide particles.

For example, when copper particles are used as metal particles, the copper becomes copper ions, which inhibit the growth of bacteria and inactivate viruses. When cuprous oxide particles are used as metal oxide particles, the disproportionation reaction between cuprous oxide ( _Cu2O ) and cupric oxide (CuO) inhibits the growth of bacteria and inactivates viruses.

(2-2) The thickness of the printed film is preferably 0.5 μm to 100 μm, and more preferably 1 μm to 50 μm. If the thickness exceeds 100 μm, a large amount of printing ink containing metal particles or metal oxide particles and a binder resin is used, which is not economical. Also, if the thickness is less than 0.5 μm, the adhesion of the metal particles or metal oxide particles in the printed film may be insufficient.

(2-3) On the other hand, the median value of the particle size distribution of the metal particles or metal oxide particles is preferably 1/3 or less of the film thickness of the printed film, and more preferably 1/3 or less of the film thickness and 0.05 μm or more and 10 μm or less. When metal particles or metal oxide particles having a median value of the particle size distribution exceeding either 1/3 or 10 μm of the film thickness are used, the smoothness of the printed film may be impaired. Furthermore, when the median value of the particle size distribution is less than 0.05 μm, it may be difficult to disperse the metal particles or metal oxide particles when preparing the printing ink. The particle size distribution of the metal particles or metal oxide particles can be measured by a particle size distribution meter using laser diffraction.

[Printed matter]
The printed matter according to the present invention is formed by forming the above-mentioned printing film on the surface of a substrate. The substrate may be paper, wood, cloth, plastic, metal, ceramic, glass, or the like, and may be any substrate, whether it is a sheet-fed type or a continuous long-length type in a strip shape. The thickness and size of the substrate are appropriately selected according to the purpose of the printed matter.

Applications for printed materials include a wide range of printing supplies, including banknotes, publications, packaging materials such as wrapping paper and bags, building materials such as decorative panels and paper, electrical equipment, and sanitary ware.

In addition, if the surface of the metal particles or metal oxide particles exposed from the surface of the printed film becomes contaminated, etc., and the antibacterial and antiviral properties are reduced, the surface of the printed film can be treated again with atmospheric pressure plasma to restore the antibacterial and antiviral properties.

[Method of manufacturing printed matter]
(1) A method for producing a printed matter according to the present invention includes the steps of:
A printing step of printing ink containing antibacterial and antiviral metal particles or metal oxide particles and a binder resin on a surface of a substrate to form a coating of the printing ink;
a curing step of applying active energy rays to the coating to cure it and form a printed cured film;
an atmospheric pressure plasma treatment step of irradiating the surface of the printed cured film with atmospheric pressure plasma to remove the binder resin covering the surfaces of metal particles or metal oxide particles present on or in the vicinity of the surface of the printed cured film, thereby exposing a part of the surfaces of the metal particles or metal oxide particles;
The present invention is characterized by having the following.

(2) Printing process (2-1) Constitution of printing ink The printing ink used in the printing process of the present invention contains antibacterial and antiviral metal particles or metal oxide particles and a binder resin as essential components, and when it is a colored ink, it contains an inorganic pigment or an organic pigment (dye) as a colorant. Note that printing ink that does not contain a colorant is sometimes called OP varnish (varnish for overprinting).

As the binder resin, cellulose-based resin, rosin-modified resin, polyamide-based resin, urethane-based resin, vinyl-based resin, polyester-based resin, acrylic-based resin, alkyd-based resin, epoxy-based resin, ultraviolet-curing resin, etc. can be used. In addition, the rosin-modified resin includes rosin-modified phenolic resin, rosin esters such as rosin-modified pentaerythritol ester, and rosin-modified maleic acid resin. The ultraviolet-curing resin includes acrylic ultraviolet-curing resin and rosin-modified epoxy acrylate, which are used in combination with a photopolymerization initiator. In addition, the epoxy-based resin is used in combination with a polymerization initiator. These binder resins are appropriately selected in consideration of adhesion to the substrate.

In addition, the printing ink needs to have fluidity for printing, and may contain a solvent such as water or an organic solvent to provide fluidity. As the organic solvent, alcohol-based, ketone-based, hydrocarbon-based, glycol-based, ether-based, ester-based solvents, oils and fats, hydrocarbons, etc. can be used. When the epoxy resin is used, a reactive diluent that reacts with the epoxy resin to harden the resin may be used as the solvent. When an ultraviolet-curable resin is used, a reactive diluent that reacts with the ultraviolet-curable resin to harden the resin may be used as the solvent. It is necessary to select a solvent that does not erode the substrate during the printing process.

In order for antibacterial and antiviral metal particles or metal oxide particles to be uniformly dispersed in the printing film, it is necessary to uniformly disperse these particles in the printing ink. For this reason, a dispersant that has an amine-containing group, a hydroxyl group, a carboxyl group, or an epoxy group as a functional group and improves the dispersion stability of the metal particles or metal oxide particles may be used in combination.

Preferred specific examples of commercially available dispersants include:
Manufactured by Lubrizol Japan, Ltd. SOLSPERSE3000, SOLSPERSE9000, SOLSPERSE11200, SOLSPERSE13000, SOLSPERSE13240, SOLSPERSE13650, SOLSPERSE13940, SOLSPERSE16000, SOL SPERSE17000, SOLSPERSE18000, SOLSPERSE20000, SOLSPERSE21000, SOLSPERSE24000SC, SOLSPERSE24000GR, SOLSPERSE26000, SOLSPERSE27000, SOLSPERSE28000, SOLSPERSE31845, SOLSPER SE32000, SOLSPERSE32500, SOLSPERSE32550, SOLSPERSE32600, SOLSPERSE33000, SOLSPERSE33500, SOLSPERSE34750, SOLSPERSE35100, SOLSPERS E35200, SOLSPERSE36600, SOLSPERSE37500, SOLSPERSE38500, SOLSPERSE39000, SOLSPERSE41000, SOLSPERSE41090, SOLSPERSE53095, SOLSPERSE 55000, SOLSPERSE56000, SOLSPERSE76500, etc.;
Disperbyk-101, Disperbyk-103, Disperbyk-107, Disperbyk-108, Disperbyk-109, Disperbyk-110, Disperbyk-111, Disperbyk-112, Disperbyk-116, Disperbyk-130, Disperbyk-140, Disperbyk-14 manufactured by BYK Japan Co., Ltd. 2, Disperbyk-145, Disperbyk-154, Disperbyk-161, Disperbyk-162, Disperbyk-163, Disperbyk-164, Disperbyk-165, Disperbyk-166, Disperb yk-167, Disperbyk-168, Disperbyk-170, Disperbyk- 171, Disperbyk-174, Disperbyk-180, Disperbyk-181, Disperbyk-182, Disperbyk-183, Disperbyk-184, Disperbyk-185, Disperbyk-190, Dispe rbyk-2000, Disperbyk-2001, Disperbyk-2020, Dispe rbyk-2025, Disperbyk-2050, Disperbyk-2070, Disperbyk-2095, Disperbyk-2150, Disperbyk-2155, Anti-Terra-U, Anti-Terra-203, Anti-Ter ra-204, BYK-P104, BYK-P104S, BYK-220S, BYK-6919, etc.;
EFKA4008, EFKA4046, EFKA4047, EFKA4015, EFKA4020, EFKA4050, EFKA4055, EFKA4060, EFKA4080, EFKA4300, EFKA4330, EFKA4400, EFKA4401, EFKA4402, EFKA4403, EFKA4500, EFKA4510, EFKA453 manufactured by BASF Japan Ltd. 0, EFKA4550, EFKA4560, EFKA4585, EFKA4800, EFKA5220, EFKA6230, JONCRYL67, JONCRYL678, JONCRYL586, JONCRYL611, JONCRYL680, JONCRYL682, JONCRYL690, JONCRYL819, JONCRYL-JDX5050, etc.;
Examples of the additives include Ajisper PB-711, Ajisper PB-821, and Ajisper PB-822 manufactured by Ajinomoto Fine-Techno Co., Ltd.

In addition, known plasticizers may be added to the printing ink to give flexibility to the printed film.

(2-2) Method for Producing Printing Ink The printing ink according to the present invention, which contains antibacterial and antiviral metal particles or metal oxide particles and a binder resin, can be produced using a known dispersion method.

Known dispersion methods include a method in which a vehicle (also called a varnish) composed of a resin and a solvent is mixed with the solvent in a three-roll mill to prepare a mill base, and then additional vehicles, solvents, and the above-mentioned metal particles or metal oxide particles are added to the mill base and let down to disperse; or a method in which, using a medium such as beads, balls, or Ottawa sand, the metal particles or metal oxide particles are pulverized and dispersed in a solvent in a medium stirring mill such as a bead mill, ball mill, sand mill, or paint shaker to prepare a dispersion, and then a vehicle is added to the dispersion. In addition, when dispersing the metal particles or metal oxide particles, the above-mentioned dispersant may be added as appropriate. Furthermore, the viscosity of the printing ink is appropriately adjusted to ensure printing suitability.

The content of metal particles or metal oxide particles in the printing ink is preferably 0.1% to 20% by mass, more preferably 0.1% to 15% by mass, and even more preferably 0.1% to 10% by mass, based on the total of the binder resin and the metal particles or metal oxide particles. If the content is less than 0.1% by mass, it may be difficult to exhibit the antibacterial and antiviral effects of the metal particles or metal oxide particles, and if it exceeds 20% by mass, the color of the printed film may be colored by these particles, reducing the coloring freedom of the printed film. If the content of these particles exceeds 20% by mass, the amount of binder resin in the printed film may decrease, and some of the metal particles or metal oxide particles may peel off from the printed film. Taking these factors into consideration, the content is appropriately set within the range of 0.1% to 20% by mass based on the total of the binder resin and the metal particles or metal oxide particles, taking into account the color of the printed film.

(2-3) Printing Method The method for printing the printing ink containing antibacterial and antiviral metal particles or metal oxide particles and a binder resin on the surface of the substrate can be known letterpress printing, intaglio printing, stencil printing, inkjet printing, etc. The printing device can be a sheet-fed printing machine or a continuous printing machine such as a rotary press or a rotary screen.

(3) Curing Step Examples of active energy rays that cure the coating of the printed printing ink to form a printed cured film include electron beams (electron beam curable resins), ultraviolet rays (e.g., acrylic ultraviolet curable resins), infrared rays (e.g., epoxy thermosetting resins), as well as X-rays, α-rays, β-rays, γ-rays, etc., depending on the type of binder resin used.

(4) Atmospheric Pressure Plasma Treatment Step (4-1) Atmospheric Pressure Plasma Apparatus The "atmospheric pressure plasma apparatus" used in the atmospheric pressure plasma treatment step, in which atmospheric pressure plasma is applied to the surface of the printed cured film to remove the binder resin covering the surface of the metal particles or metal oxide particles present on or near the surface of the printed cured film to expose a part of the surface of the metal particles or metal oxide particles, is an apparatus that can apply plasma without requiring a vacuum facility, and is widely used for purposes such as surface modification, removal of surface contaminants, and roughening of surfaces. As with the vacuum plasma apparatus, the power source types include medium frequency (MHz), high frequency (MHz), and microwave (GHz), and it is said that the higher the frequency, the less the surface roughness and the more uniform the effect can be expected. Nitrogen, argon, helium, etc. are used as the main component of the plasma gas (process gas), and a small amount of additive gas (active species) is mixed depending on the purpose. The process gas is almost always determined taking into account the gas cost depending on the size of the facility.

In addition, since the decomposition and removal effect of organic matter differs depending on the added gas (active species), it is preferable to add one or more types selected from oxygen, nitrogen, hydrogen, water, and ammonia as the active species to the process gas. When hydrogen is added as the active species, a reduction effect on the surface of metal oxide particles is expected. That is, when copper oxide (CuO) particles and cuprous oxide (Cu ₂ O) particles are compared as metal oxide particles, it is known that monovalent cuprous oxide (Cu ₂ O) has a better antibacterial and antiviral effect than divalent copper oxide (CuO). For this reason, by performing atmospheric pressure plasma treatment with hydrogen added as an active species on metal oxide particles that have been left in the atmosphere for a long period of time and oxidized from cuprous oxide (Cu ₂ O) to copper oxide (CuO), it is possible to return a part of the particles to the state of cuprous oxide (Cu ₂ O) and activate its antibacterial and antiviral properties.

Furthermore, atmospheric pressure plasma devices can be broadly divided into "direct type" and "remote type." In the "direct type," the object to be irradiated with atmospheric pressure plasma is earthed, whereas in the "remote type," there is an earth inside the atmospheric pressure plasma device, and only the plasma is irradiated to the object. If the surface of the object to be irradiated with atmospheric pressure plasma is not a uniform conductor or insulator, but a mixture of conductors and insulators, the plasma becomes unstable and a lightning-like arc is generated toward the object. In particular, since the arc is generated toward the conductor, it may damage the object. The above-mentioned "remote type," which has an earth inside the atmospheric pressure plasma device, is highly preferable because it is difficult for an arc to occur.

(4-2) Effects of the atmospheric pressure plasma treatment process Figure 3 is an explanatory diagram of the process relating to the manufacturing method of the printed matter described above, in which Figure 3(A) is an explanatory cross-sectional view of the coating immediately after printing the printing ink of the present invention on the surface of a substrate, Figure 3(B) is an explanatory cross-sectional view of the printed cured film formed by hardening the above coating after drying, and Figure 3(C) is an explanatory cross-sectional view showing the state in which the binder resin covering the surfaces of metal particles or metal oxide particles present on the surface of the above printed cured film has been removed to expose the surfaces of metal particles or metal oxide particles.

As can be seen from FIG. 3(A), which shows the cross section of the coating immediately after the printing process, in the printing ink coating 302 before drying, some of the metal particles or metal oxide particles 301 are separated from the substrate 300 and exist in a floating state due to uncured binder resin, solvent, etc.

After the curing process, the solvent is removed from the printed cured film 303 as shown in FIG. 3(B), leaving the metal particles or metal oxide particles 301 in contact with the substrate 300, and the surfaces of the metal particles or metal oxide particles 301 are covered with the cured binder resin 301a, making it difficult for antibacterial and antiviral metal ions to dissolve out of the metal particles or metal oxide particles 301.

However, after atmospheric pressure plasma treatment, the surfaces of the metal particles or metal oxide particles 301 are exposed with the binder resin 301a removed as shown in FIG. 3(C), making it possible to produce printed matter in which the antibacterial and antiviral effects of the metal particles or metal oxide particles 301 are fully exerted.

By the way, when the surface of metal particles or metal oxide particles is treated by irradiating atmospheric pressure plasma, the particle surface is modified by the above-mentioned active species gas contained in the process gas, and the activity of the metal particles or metal oxide particles may be improved. For example, when copper particles are used as metal particles, copper is oxidized to copper oxide (CuO) when left in the air, but as mentioned above, monovalent cuprous oxide (Cu ₂ O) has a better antibacterial and antiviral effect than divalent copper oxide (CuO). Therefore, by irradiating atmospheric pressure plasma containing active species in the process gas, it is possible to modify divalent copper oxide (CuO) to monovalent cuprous oxide (Cu ₂ O) which has a better antibacterial and antiviral effect.

[Apparatus used in the method for producing printed matter]
(1) Apparatus According to First Embodiment The apparatus according to the first embodiment relates to a gravure printing apparatus to which a long substrate is applied.

That is, as shown in FIG. 1, the main parts of this device are an unwinding core 101 that unwinds a long substrate 100 such as paper or cloth, a gravure roll 108 that prints a printing ink 111 containing antibacterial and antiviral metal particles or metal oxide particles and a binder resin on the surface of the long substrate 100 unwound from the unwinding core 101, a drying box 114 that dries and hardens the coating of the printed printing ink (see the coating shown by reference numeral 302 in FIG. 3A) to form a printed cured film (see the printed cured film shown by reference numeral 303 in FIG. 3B), an atmospheric pressure plasma head 126 that irradiates atmospheric pressure plasma onto the surface of the printed cured film formed on the long substrate 100 conveyed from the drying box 114, and a winding core 127 that winds up the long substrate 100 in which the binder resin covering the surfaces of the metal particles or metal oxide particles has been removed by the irradiated atmospheric pressure plasma, exposing the surfaces of the metal particles or metal oxide particles.

The method for producing the printed matter according to the present invention using the device according to the first embodiment will be described below. As shown in FIG. 1, the long substrate 100 unwound from the unwinding core 101 is transported to the pressure roll 107 via the guide roll 102, tension sensor roll 103, guide roll 104, drive roll 105, and tension sensor roll 106, and is then transported toward the drying box 114 via the tension sensor roll 112 and drive roll 113. The unwinding tension of the long substrate 100 unwound from the unwinding core 101 is feedback-controlled from the tension sensor roll 103 to the unwinding core 101, and the drag applied to the pressure roll 107 of the long substrate 100 is feedback-controlled from the tension sensor roll 106 to the drive roll 105 and from the tension sensor roll 112 to the drive roll 113.

In addition, a printing ink 111 containing antibacterial and antiviral metal particles or metal oxide particles and a binder resin is printed by a gravure roll 108 on the surface of the long substrate 100 transported on a pressure roll 107. The printing ink 111 is stored in an ink vat 110, and this printing ink 111 adheres to the surface of the gravure roll 108 as shown in FIG. 1, and excess ink is scraped off by a doctor blade 109.

The long substrate 100 with the coating of the printing ink 111 formed on its surface is then transported into a drying box 114 in which drying heaters 120, 121, and 122 are arranged, and passes through guide rolls 115 and 116, tension sensor roll 117, guide roll 118, and drive roll 119, and the long substrate 100 with the printed cured film formed on its surface, which is the dried and cured coating, is transported out of the drying box 114. In addition, the tension during drying is feedback-controlled from the tension sensor roll 117 to the drive roll 119.

In the first embodiment, the printing ink that is cured by drying or heating is used, so the drying heaters 120, 121, and 122 are arranged inside the drying box 114. However, if a printing ink that is cured by applying active energy rays such as ultraviolet rays is used, it is possible to accommodate this by placing an active energy ray irradiation device between the drying box 114 and the atmospheric plasma head 126.

The long substrate 100 with the printed cured film formed on its surface is then wound onto the winding core 127 via the guide roll 123, tension sensor roll 124, and guide roll 125. Atmospheric plasma is irradiated from the atmospheric plasma head 126 installed between the guide roll 123 and the tension sensor roll 124 toward the surface of the printed cured film on the long substrate 100, removing the binder resin that was covering the surface of the metal particles or metal oxide particles.

The distance between the atmospheric plasma head 126 and the printed cured film on the long substrate 100 is set narrow, at about 1 to 5 mm, to avoid disturbances, and the winding tension applied to the winding core 127 is feedback-controlled from the tension sensor roll 124 to the winding core 127.

In Figure 1, the rolls driven by the motor are marked with M (motor), the tension sensor roll with TP (tension pickup), and the free roll with F (free).

(2) Apparatus According to a Second Embodiment An apparatus according to a second embodiment also relates to a gravure printing apparatus to which a long substrate is applied.

That is, as shown in FIG. 2, the main parts of this device are an unwinding core 201 that unwinds the long substrate 200, a gravure roll 208 that prints a printing ink 211 containing antibacterial and antiviral metal particles or metal oxide particles and a binder resin on the surface of the long substrate 200 unwound from the unwinding core 201, a drying box 214 that dries and hardens a coating of the printed printing ink (see the coating shown by reference numeral 302 in FIG. 3A) to form a printed cured film (see the printed cured film shown by reference numeral 303 in FIG. 3B), an atmospheric pressure plasma head 226 that is disposed in a position opposite the water-cooled driving roll 229 and irradiates atmospheric pressure plasma onto the surface of the printed cured film of the long substrate 200 conveyed from the drying box 214, and a winding core 227 that winds up the long substrate 200 in which the binder resin covering the surfaces of the metal particles or metal oxide particles has been removed by the irradiated atmospheric pressure plasma and the surfaces of the metal particles or metal oxide particles have been exposed.

The method for producing the printed matter according to the present invention using the device according to the second embodiment will be described below. As shown in FIG. 2, the long substrate 200 unwound from the unwinding core 201 is transported to the pressure roll 207 via the guide roll 202, tension sensor roll 203, guide roll 204, drive roll 205, and tension sensor roll 206, and is then transported toward the drying box 214 via the tension sensor roll 212 and drive roll 213. The unwinding tension of the long substrate 200 unwound from the unwinding core 201 is feedback-controlled from the tension sensor roll 203 to the unwinding core 201, and the drag applied to the pressure roll 207 of the long substrate 200 is feedback-controlled from the tension sensor roll 206 to the drive roll 205 and from the tension sensor roll 212 to the drive roll 213.

In addition, a printing ink 211 containing antibacterial and antiviral metal particles or metal oxide particles and a binder resin is printed by a gravure roll 208 on the surface of the long substrate 200 transported on a pressure roll 207. The printing ink 211 is stored in an ink vat 210, and this printing ink 211 adheres to the surface of the gravure roll 208 as shown in FIG. 2, and excess ink is scraped off by a doctor blade 209.

The long substrate 200 with a coating of the printing ink 211 formed on its surface is then transported into a drying box 214 in which drying heaters 220, 221, and 222 are arranged, and passes through guide rolls 215, 216, tension sensor roll 217, guide roll 218, and drive roll 219, and the long substrate 200 with a printed cured film formed on its surface, where the coating has dried and cured, is transported out of the drying box 114. In addition, the tension during drying is feedback-controlled from the tension sensor roll 217 to the drive roll 219.

In the second embodiment, since printing ink that hardens by drying or heating is used, drying heaters 220, 221, and 222 are arranged in the drying box 214. However, if printing ink that hardens by applying active energy rays such as ultraviolet rays is used, it is possible to accommodate this by placing an active energy ray irradiation device between the drying box 214 and the atmospheric pressure plasma head 226.

The long substrate 200 with the printed cured film formed on its surface is then wound around the winding core 227 via the tension sensor roll 228, the water-cooled drive roll 229, the guide roll 223, the tension sensor roll 224, and the guide roll 225. Atmospheric plasma is irradiated from the atmospheric plasma head 226, which is positioned opposite the water-cooled drive roll 229, toward the surface of the printed cured film on the long substrate 200, and the binder resin covering the surface of the metal particles or metal oxide particles is removed.

The distance between the atmospheric plasma head 226 and the printed cured film on the long substrate 200 transported on the water-cooled drive roll 229 is set narrow, at about 1 to 5 mm, to avoid disturbances, and the winding tension wound around the winding core 227 is feedback-controlled from the tension sensor roll 224 to the winding core 227.

As described above, the device according to the second embodiment irradiates atmospheric pressure plasma to the long substrate 200 transported on the water-cooled drive roll 229, and therefore has a higher cooling effect than the device according to the first embodiment, which irradiates atmospheric pressure plasma to the long substrate 100 in a floating state (in the air) as shown in FIG. 1, and has the advantage of being less likely to damage the long substrate on which the printed cured film is formed.

In Figure 2, the rolls driven by the motor are marked with M (motor), the tension sensor roll with TP (tension pickup), and the free roll with F (free).

The following provides a detailed explanation of the embodiments of the present invention.

[Production of antibacterial and antiviral printed materials]
In this example, copper powder [UCP-030 manufactured by Sumitomo Metal Mining Co., Ltd.] having a median value in the particle size distribution of 0.5 μm was used as the antibacterial and antiviral metal particles, a rosin-modified phenolic resin having a molecular weight of 100,000 was used as the binder resin, a solvent prepared by blending soybean oil, which is an oil, and AF7 solvent (manufactured by ENEOS Corporation), which is a hydrocarbon, was used, and glossy paper, which is difficult for ink to penetrate, was used as the base material.

(Preparation of printing ink)
A vehicle composed of 50% by weight of rosin-modified phenolic resin and 50% by weight of the above solvent was prepared, and the vehicle, copper powder, and the above solvent were kneaded in a three-roll mill to prepare a mill base. The vehicle was added to the mill base to adjust the three compositions [copper particle content: 0% by weight, 10% by weight, and 20% by weight] listed in the "Copper Particle Content (wt%)" column in Table 1, and letdown was performed on the three-roll mill. At that time, the above solvent was added to adjust the viscosity of the printing ink. Note that the printing ink with a copper particle content of 0% by weight was prepared by adding the above solvent for viscosity adjustment to the vehicle. In addition, the viscosity of each printing ink was adjusted with a solvent so that the film thickness of the printed cured film after printing and drying was 3 μm.

(printing, curing, atmospheric pressure plasma treatment)
Using the prepared printing ink, a printed item was produced in which a printed, cured film with a thickness of 3 μm was formed on the surface of glossy paper, which is a long substrate, using the device shown in FIG. 1. Furthermore, the surface of the printed, cured film was irradiated with atmospheric pressure plasma according to the conditions described below to produce an antibacterial and antiviral printed item.

That is, a printed matter with a printed cured film containing 0% copper particles by weight, a printed matter with a printed cured film containing 10% copper particles by weight, and a printed matter with a printed cured film containing 20% copper particles by weight were subjected to atmospheric plasma treatment using an atmospheric plasma head with a distance of 3 mm from the printed cured film.

The process gas used was argon, and the mixed gas listed in the "With/Without Hydrogen Added" column in Table 1 ("With Hydrogen Added" is a mixed gas of 10% oxygen and 4% hydrogen, and "Without Hydrogen Added" is oxygen only) was added to the process gas. The power (0 W, 50 W, 100 W) listed in the "Plasma Power (W)" column in Table 1 was applied from a high-frequency power source (13.5 MHz) to the atmospheric pressure plasma head (head width 100 mm) of a remote atmospheric pressure plasma generator, and atmospheric pressure plasma was irradiated onto the surface of the printed cured film of the printed matter transported at the speed (30 m/min, 60 m/min) listed in the "Transport Speed (m/min)" column in Table 1. In order to prevent each printed matter from being damaged by the heat load caused by continuous irradiation of atmospheric pressure plasma, the high frequency power source was turned off when the transport of the printed matter was stopped, and the high frequency power source was turned on only when the printed matter was being transported.

[Evaluation of antibacterial and antiviral printed matter]
(Evaluation sample)
A square measuring 50 mm on each side was cut out from each printed matter produced under the conditions shown in Table 1 to obtain evaluation samples Nos. 1 to 30.

(evaluation)
The evaluation samples Nos. 1 to 30 shown in Table 1 were evaluated for antibacterial and antiviral properties.

(1) Evaluation of antibacterial properties The evaluation of antibacterial properties was performed based on JIS Z 2801.
Antibacterial activity value less than 2.0 is rated as ×.
An antibacterial activity value of 2.0 or more was rated as "good."

The unprocessed test piece described in JIS Z 2801 was made of glossy paper that had not been printed.

(2) Evaluation of antiviral properties The evaluation of antiviral properties is based on ISO 21702.
Antibacterial activity value less than 2.0 is rated as ×.
An antibacterial activity value of 2.0 or more was rated as "good."

The unprocessed test piece described in ISO 21702 was made of glossy paper that had not been printed on.

(Evaluation Results)
The evaluation results are shown in Table 1.

(1) Evaluation results of sample No. 11 [plasma power 50 (W), conveying speed 30 (m/min), hydrogen added, copper particle content 10 (wt%)] and sample No. 12 [plasma power 50 (W), conveying speed 30 (m/min), hydrogen added, copper particle content 20 (wt%)] rated ◯;
Evaluation results of sample No. 23 [plasma power 100 (W), conveying speed 30 (m/min), hydrogen added, copper particle content 10 (wt%)] and sample No. 24 [plasma power 100 (W), conveying speed 30 (m/min), hydrogen added, copper particle content 20 (wt%)] rated ◯:
From the evaluation results of sample No. 29 [plasma power 100 (W), conveying speed 60 (m/min), hydrogen added, copper particle content 10 (wt%)] and sample No. 30 [plasma power 100 (W), conveying speed 60 (m/min), hydrogen added, copper particle content 20 (wt%)], which were rated ◯,
Antibacterial and antiviral effects were confirmed when the plasma power was 50W to 100W, the conveying speed was 30m/min to 60 (m/min), and hydrogen was added to the plasma gas (hydrogen addition).

(2) On the other hand, sample No. 8 [plasma power 50 (W), conveying speed 30 (m/min), no hydrogen addition, copper particle content 10 (wt%)] and sample No. 9 [plasma power 50 (W), conveying speed 30 (m/min), no hydrogen addition, copper particle content 20 (wt%)], which are the same conditions as sample Nos. 11 and 12 except for the condition of "no hydrogen addition", were rated as x.
Sample No. 20 [plasma power 100 (W), conveying speed 30 (m/min), no hydrogen addition, copper particle content 10 (wt%)] and sample No. 21 [plasma power 100 (W), conveying speed 30 (m/min), no hydrogen addition, copper particle content 20 (wt%)], which are the same conditions as sample Nos. 23 and 24 except for the condition of "no hydrogen addition", were rated as x.
Sample No. 26 [plasma power 100 (W), conveying speed 60 (m/min), no hydrogen addition, copper particle content 10 (wt%)] and sample No. 27 [plasma power 100 (W), conveying speed 60 (m/min), no hydrogen addition, copper particle content 20 (wt%)], which are the same conditions as sample Nos. 29 and 30 except for the condition of "no hydrogen addition", were also rated as x.
When the plasma power is 50 W to 100 W and the transport speed is 30 m/min to 60 (m/min), the binder resin covering the copper particle surface near the surface of the printed cured film is removed, but it is presumed that the copper particle surface is oxidized by the oxygen in the added gas, preventing the antibacterial and antiviral effects from being exerted.

(3) The mixed gas of oxygen and hydrogen ("Hydrogen added" in Table 1 is a mixed gas of 10% oxygen and 4% hydrogen) that is added to the process gas (argon gas) as an active species is likely to be affected by the type of binder resin that covers the surface of the copper particles, the thickness of the coating, and the atmospheric pressure plasma irradiation conditions. Therefore, the ratio of oxygen and hydrogen in the mixed gas should be set appropriately after checking the antibacterial and antiviral effects of the resulting printed matter.

According to the printed matter of the present invention, some of the surfaces of the antibacterial and antiviral metal particles or metal oxide particles contained in the printed film are partially exposed, making it possible to fully exert the antibacterial and antiviral effects of these particles. For this reason, printed products obtained by processing the above printed matter have industrial potential for use in the medical field, etc.

100 Long substrate 101 Unwinding core 102, 104, 115, 116, 118, 123, 125 Guide roll 103, 106, 112, 117, 124 Tension sensor roll 105, 113, 119, Drive roll 107 Pressure roll 108 Gravure roll 109 Doctor blade 110 Ink vat 111 Ink 114 Drying box 120, 121, 122 Drying heater 126 Atmospheric pressure plasma head 127 Winding core 200 Long substrate 201 Unwinding core 202, 204, 215, 216, 218, 223, 225 Guide roll 203, 206, 212, 217, 228, 224 Tension sensor roll 205, 213, 219 Drive roll 229 Water-cooled drive roll 207 Pressure roll 208 Gravure roll 209 Doctor blade 210 Ink vat 211 Ink 214 Drying box 220, 221, 222 Drying heater 226 Atmospheric pressure plasma head 227 Winding core 300 Substrate 301 Antibacterial and antiviral metal particles or metal oxide particles 302 Coating of printing ink before drying 303 Printed cured film 301a Binder resin covering the surface of metal particles or metal oxide particles

Claims (14)

A printing film formed by using a printing ink containing antibacterial and antiviral metal particles or metal oxide particles and a binder resin,
a part of the surface of a part of metal particles or metal oxide particles contained in the printing film is exposed on or near the surface of the printing film ;
The printed film has a thickness of 0.5 μm to 100 μm, and the median value of the particle size distribution of the metal particles or metal oxide particles is ⅓ or less of the thickness of the printed film. The printed film according to claim 1 , characterized in that the antibacterial and antiviral metal particles are composed of any one of copper particles, silver particles, nickel particles, and zinc particles. 2. The printed film according to claim 1 , characterized in that the antibacterial and antiviral metal oxide particles are composed of cuprous oxide particles. A printing film formed using a printing ink containing antibacterial and antiviral metal oxide particles and a binder resin,
a part of the surface of an oxide particle of a part of a metal contained in the printing film is exposed on or near the surface of the printing film;
The printed film is further characterized in that the antibacterial and antiviral metal oxide particles are composed of cuprous oxide particles. A printed matter characterized in that the printing film according to any one of claims 1 to 4 is formed on the surface of a substrate. The printed matter according to claim 5, characterized in that the substrate is made of any one of paper, wood bark, cloth, plastic plate, metal plate, ceramic plate, and glass plate. A printing step of printing ink containing antibacterial and antiviral metal particles or metal oxide particles and a binder resin on a surface of a substrate to form a coating of the printing ink;
a curing step of applying active energy rays to the coating to cure it and form a printed cured film;
an atmospheric pressure plasma treatment step of irradiating the surface of the printed cured film with atmospheric pressure plasma to remove the binder resin covering the surfaces of metal particles or metal oxide particles present on or in the vicinity of the surface of the printed cured film, thereby exposing a part of the surfaces of the metal particles or metal oxide particles;
A method for producing a printed matter, comprising the steps of: The method for producing a printed matter according to claim 7, characterized in that the process gas used in the atmospheric pressure plasma treatment step is mainly composed of nitrogen, argon gas, or helium, and one or more active species selected from oxygen, nitrogen, hydrogen, water, and ammonia are added to the process gas. The method for producing a printed matter according to claim 7 or 8, characterized in that in the atmospheric pressure plasma treatment step, activated species are irradiated onto the surface of the printed cured film using a remote atmospheric pressure plasma generator. The method for producing a printed matter according to any one of claims 7 to 9, characterized in that the antibacterial and antiviral metal particles used in the printing process are composed of copper particles, silver particles, nickel particles, or zinc particles. The method for producing a printed matter according to any one of claims 7 to 10, characterized in that the binder resin used in the printing process is made of rosin-modified phenolic resin, the antibacterial and antiviral metal particles are made of copper particles, the process gas used in the atmospheric pressure plasma treatment process is argon gas, and a mixed gas of 10% oxygen and 4% hydrogen is added to the process gas, and 50 W to 100 W of power is applied from a high-frequency power source to the atmospheric pressure plasma head of a remote atmospheric pressure plasma generator, and atmospheric pressure plasma is irradiated to the printed cured film of the substrate transported at a speed of 30 m/min to 60 m/min. The method for producing a printed matter according to any one of claims 7 to 9, characterized in that the antibacterial and antiviral metal oxide particles used in the printing process are composed of cuprous oxide particles. The method for producing a printed matter according to any one of claims 7 to 12, characterized in that the substrate is made of any one of paper, wood bark, cloth, plastic plate, metal plate, ceramic plate, and glass plate. A method for treating a printed film formed by using a printing ink containing antibacterial and antiviral cuprous oxide particles and a binder resin, the surface of a part of the cuprous oxide particles being exposed from the surface of the printed film, comprising:
A method for treating a printed film, comprising irradiating the surfaces of cuprous oxide particles exposed from the surface of the printed film with atmospheric pressure plasma to reduce a portion of the oxidized copper oxide to cuprous oxide, thereby activating the antibacterial and antiviral properties of the cuprous oxide particles.

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