JP6894654B1 - Manufacturing method of antibacterial printing sheet and antibacterial printing sheet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a printing sheet having a coating layer for receiving ink on at least one surface of a substrate, which is excellent in antibacterial / antiviral property and printability, and has good adhesion between the substrate and the coating layer. To provide a printing sheet having good antistatic performance, less likely to cause problems such as paper jams during printing, and excellent in various properties such as water resistance and weather resistance, and a method for manufacturing the printing sheet. In a continuous phase made of an acrylic polymer, zincpyrythion is 0.40% by mass or more and 2.00% by mass or less, zinc oxide is 0.10% by mass or more and 1.00% by mass or less, and clay is 30% by mass or more. It is a printing sheet characterized by having a coat layer in which 50% by mass or less and calcium carbonate are blended in a ratio of 10% by mass or more and 30% by mass or less. [Selection diagram] None

Description

The present invention relates to an antibacterial printing sheet and a method for producing an antibacterial printing sheet. More specifically, the present invention relates to a technique for improving the antibacterial property, printability, water resistance, weather resistance, antistatic property, etc. of a printing sheet having an antibacterial coat layer on the surface of a base material.

Conventionally, as a printing sheet, a sheet using paper, a plastic sheet made of polyester, polypropylene, or the like as a base material has been known. In particular, for example, in applications such as posters and outdoor printed matter that require characteristics such as water resistance and tear strength, a plastic sheet or a thermoplastic resin is molded into a sheet by adding an inorganic filler and a small amount of additives. Synthetic paper obtained by the above is mainly used.

In addition, now that environmental protection has become an international issue, reducing the consumption of thermoplastics and paper materials has been greatly studied. From this point of view, inorganic powder is incorporated into thermoplastics. A highly filled thermoplastic composition containing an inorganic substance powder has been proposed and has been put into practical use as a printing sheet as described above (see, for example, Patent Document 1 and the like).

By the way, when a sheet made of the above-mentioned material is considered as a printing application in particular, the surface of the plastic sheet may be modified in order to improve the adhesive force between the ink and the plastic sheet on the printing surface and the color development. There are many. For example, in the printing sheet described in Patent Document 2, a coat layer in which a specific amount of clay and light calcium carbonate is blended in a continuous phase made of an acrylic polymer is formed on one side or both sides of a base material. ..

In recent years, antibacterial and antiviral properties of sheets have been particularly required, and sheet materials have been developed to meet such requirements. For example, Patent Document 3 describes an antibacterial and antifungal sheet in which the surface of a substrate is coated with an organic emulsion containing an antibacterial / antifungal agent such as zinc pyrithione together with a filler such as calcium carbonate. Patent Document 4 describes antibacterial and antifungal packing in which a film in which an antibacterial and antifungal agent is mixed with a raw material resin is attached to one or both sides of a sheet. Further, Patent Document 5 discloses an antimicrobial wallpaper in which a binder cured product containing an antimicrobial component is scattered in an island shape or a mottled shape on one side of a flexible sheet.

International Publication No. WO2014 / 109267 Japanese Patent No. 6738107 Japanese Unexamined Patent Publication No. 2003-277202 Japanese Unexamined Patent Publication No. 2005-75403 Japanese Unexamined Patent Publication No. 2020-41247

However, even if an antibacterial / antifungal agent is contained in the surface layer of the sheet as shown in Patent Documents 3 and 4, sufficient antibacterial properties cannot always be obtained. In particular, there is a problem that antibacterial properties and antiviral properties are difficult to develop on the ink surface after printing (Note that, in the present specification, antibacterial properties, antiviral properties, antifungal properties, and agents for that purpose are collectively referred to. It may be described as "antibacterial" or "antibacterial agent"). As shown in Examples and Comparative Examples described later, simply mixing an antibacterial agent such as zinc pyrithione with the coat layer on the sheet surface does not necessarily provide sufficient antibacterial properties on the surface after printing. The same applies to the sheet described in Patent Document 5.

The above sheet may also have the problem of being unsuitable as a printing sheet. As described in Patent Document 2, if the coating layer is not properly blended, the adhesiveness to the base material layer and the coating liquid at the time of printing is poor, and there are problems such as peeling at the interface and toner not being fixed. Occurs. Depending on the composition of the coat layer, yellowing due to poor weather resistance, poor water resistance, and paper jams during printing due to charging may occur. In particular, in a sheet having an island-shaped or mottled binder cured product on the surface as described in Cited Document 5, such an island-shaped or mottled pattern may be reflected in the coating layer, and a good printed matter may not be obtained. There is.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide an improved antibacterial printing sheet and a method for producing the same. The present invention also exhibits excellent antibacterial properties in a printing sheet having a coat layer for receiving ink on at least one surface of the base material, and exhibits sufficient antibacterial properties on the surface of the printing ink layer, resulting in printability. Excellent, good adhesion between the base material and the coat layer, good antistatic performance, less likely to cause problems such as paper jams during printing, and antibacterial properties with excellent water resistance, weather resistance, etc. An object of the present invention is to provide a sheet for sex printing and a method for producing the same.

As a result of diligent studies to solve the above problems, the present inventors mixed a specific amount of zinc pyrithione as an antibacterial agent in a coat layer containing an acrylic polymer, and blended a specific amount of zinc oxide, clay, and calcium carbonate. By doing so, it was found that an antibacterial printing sheet showing high antibacterial properties and excellent printability such as adhesion to a coating liquid can be obtained.

That is, the present invention is an antibacterial printing sheet having a coat layer containing an acrylic polymer on one side or both sides of a base material, and the acrylic type is used when the total mass of the coat layer is 100% by mass. In the continuous phase composed of the polymer, zinc pyrithione is 0.40% by mass or more and 2.00% by mass or less, zinc oxide is 0.10% by mass or more and 1.00% by mass or less, clay is 30% by mass or more and 50% by mass or less, and carbon dioxide. It is an antibacterial printing sheet characterized by containing calcium in a ratio of 10% by mass or more and 30% by mass or less.

Although the present invention is not limited by a specific theory, one of the reasons why the present invention is effective is that the antibacterial agent zinc pyrithione is easily transferred to the surface. Generally, the antibacterial agent contained in the coat layer exhibits antibacterial properties by migrating and precipitating (bleeding) on the surface of the layer, so that the antibacterial effect is affected by the ease of bleeding. If it is difficult to bleed, a sufficient amount of antibacterial agent does not appear on the sheet surface, and even if bleeding does not occur on the surface of the printing ink layer, satisfactory antibacterial properties cannot be obtained. In general, the bleeding of a drug in a polymer composite material mainly depends on the amount of the drug and the compatibility between the polymer and the drug, but it is also affected by the formulation of the filler, for example, the bleeding is suppressed by the formulation of carbon black or the like. Both cases are known (for example, "Basics of Rubber Technology" edited by Japan Rubber Association, 5th edition (1992), pp. 256-257, Urabe "About Bloom Phenomenon", Japan Rubber Association. (See Vol. 26, pp. 495-497). As described above, the relationship between the size of the bleed and the composition of the filler is not uniform, and it is necessary to adjust the type and amount of the filler for each polymer composite material in order to appropriately bloom the chemical. In the present invention, as a result of a predetermined filler being blended in a specific ratio in a well-balanced manner in a continuous phase made of an acrylic polymer, the antibacterial agent zinc pyrithione is likely to bleed and excellent antibacterial properties are exhibited. .. In addition, the presence of clay, calcium carbonate, and zinc oxide causes fine irregularities based on clay and the like to be formed on the surface of the coat layer, and as a result of increasing the contact area with the printing ink layer, the antibacterial agent is applied to the surface of the ink layer. It is thought that it will be easier to shift to. In the coat layer of the present invention, the adhesiveness between the base material and the printing ink layer is improved by the anchor effect due to the fine irregularities on the surface as described above, and zinc oxide, clay, and calcium carbonate are appropriately used. It is considered that the whiteness, water resistance, weather resistance, and antistatic performance are improved by containing the mixture in a suitable composition, and the printability is improved.

In one aspect of the printing sheet of the present invention, the antibacterial printing sheet in which the base material contains a polyolefin resin and an inorganic substance powder in a mass ratio of 50:50 to 10:90 is shown. Is done.

In one aspect of the printing sheet of the present invention, an antibacterial printing sheet in which the inorganic substance powder is calcium carbonate powder is shown.

In one aspect of the printing sheet of the present invention, an antibacterial printing sheet in which the volume average particle size of the clay is 0.05 μm or more and 2.00 μm or less is shown.

In one aspect of the printing sheet of the present invention, an antibacterial printing sheet having a volume average particle size of calcium carbonate of 0.05 μm or more and 2.00 μm or less is shown.

In one aspect of the printing sheet of the present invention, an antibacterial printing sheet in which the acrylic polymer is a polymer of a (meth) acrylic acid alkyl ester is shown.

In one aspect of the printing sheet of the present invention, the (meth) acrylic acid alkyl ester is a methyl acrylate, ethyl acrylate, n-propyl acrylate, isopropyl acrylate, n-butyl acrylate, isobutyl acrylate, N-octyl acrylate, -2-ethylhexyl acrylate, isooctyl acrylate, nonyl acrylate, methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, isopropyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, methacrylic Selected from the group consisting of n-octyl acid acid, -2-ethylhexyl methacrylate, isooctyl methacrylate, 2-hydroxymethyl acrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl acrylate, 2-hydroxypropyl methacrylate. An antibacterial printing sheet of one or more types is shown.

According to the present invention, which solves the above problems, zinc pyrithione is 0.40% by mass or more and 2.00% by mass or less and zinc oxide is 0.10 by mass in a continuous phase made of an acrylic polymer on one side or both sides of the base material. Applying an acrylic polymer aqueous emulsion containing a proportions of mass% or more and 1.00% by mass or less, clay in an amount of 30% by mass or more and 50% by mass or less, and calcium carbonate in a proportion of 10% by mass or more and 30% by mass or less. It is a method for producing an antibacterial printing sheet, which is a feature thereof.

In one aspect of the method for producing an antibacterial printing sheet of the present invention, a substrate containing a polyolefin resin and an inorganic substance powder in a mass ratio of 50:50 to 10:90 is extruded into a sheet and stretched. A method for producing an antibacterial printing sheet, characterized in that the acrylic polymer aqueous emulsion is applied to one side or both sides of the base material sheet is shown.

According to the present invention, an antibacterial printing sheet having a coat layer for receiving ink on at least one surface of a substrate has excellent antibacterial properties, and the ink surface after printing also exhibits sufficient antibacterial properties, and is printable. Excellent adhesion between the base material and the coat layer, good antistatic performance, less likely to cause problems such as paper jams during printing, and excellent properties such as water resistance and weather resistance. A printing sheet can be given. Further, according to the present invention, the whiteness and texture (appropriate glossiness) of the antibacterial printing sheet are also good, and the quick-drying property of the ink when used for oil-based offset printing, UV offset printing, etc. is also good. As a result, it becomes an antibacterial printing sheet with excellent offset suitability.

Hereinafter, the present invention will be described in detail based on the embodiments.

≪Printing sheet≫
The antibacterial printing sheet of the present invention includes a sheet-like base material and a coat layer formed on at least one surface of the base material, and the coat layer is in a continuous phase made of an acrylic polymer. Zincpyridion is 0.40% by mass or more and 2.00% by mass or less, zinc oxide is 0.10% by mass or more and 1.00% by mass or less, clay is 30% by mass or more and 50% by mass or less, and calcium carbonate is 10% by mass or more. It has a mixture of 30% by mass or less.

The antibacterial printing sheet according to the present invention is not particularly limited as long as it has the above-mentioned coat layer on at least one surface of the base material, and the other configurations are not particularly limited. An intermediate layer having some function between the base material and the coat layer, for example, a sealant layer for improving the adhesion between the base material and the coat layer, and an internal printing layer for imparting coloring and a pattern to the printing sheet. , A shielding layer or the like, a protective layer or an adhesive layer on the surface of the base material on which the coat layer is not provided, and further, a protective layer or the like on the surface of the coat layer can be optionally provided.

(1) Base material The material of the base material in the antibacterial printing sheet of the present invention is not particularly limited, and may be composed of a plastic sheet containing a resin-based material as a main component, or may be made of a paper-based material. It may be composed of synthetic paper or synthetic paper. Further, as the base material, a sheet made of a thermoplastic containing an inorganic substance powder, which is a highly filled thermoplastic with an inorganic substance powder, particularly a polyolefin resin and the inorganic substance powder in a mass ratio of 50:50 to 10 It is preferable to use a sheet made of a thermoplastic containing an inorganic substance powder contained in a ratio of: 90 from the viewpoint of environmental protection and from the viewpoint of improving characteristics such as mechanical strength and heat resistance.

(Resin component)
The resin constituting the plastic sheet or the thermoplastic plastic sheet containing an inorganic substance powder is not particularly limited, and various resins may be used depending on the use, function, and the like of the printing sheet. For example, polyolefin resins such as polyethylene resins, polypropylene resins, polymethyl-1-pentene, and ethylene-cyclic olefin copolymers; ethylene-vinyl acetate copolymers, ethylene-acrylic acid copolymers, and ethylene-methacrylic acid copolymers. Functional groups such as polymers, metal salts of ethylene-methacrylic acid copolymers (ionomers), ethylene-acrylic acid alkyl ester copolymers, ethylene-methacrylic acid alkyl ester copolymers, maleic acid-modified polyethylenes, maleic acid-modified polypropylenes, etc. Containing polyolefin resin; polyamide resin such as nylon-6, nylon-6,6, nylon-6,10, nylon-6,12; fragrance of polyethylene terephthalate and its copolymer, polyethylene naphthalate, polybutylene terephthalate, etc. Thermoplastic polyester resins such as aliphatic polyester resins such as group polyester resins, polybutylene succinates and polylactic acid; polycarbonate resins such as aromatic polycarbonates and aliphatic polycarbonates; atactic polystyrenes, syndiotactic polystyrenes, acrylonitriles- Polystyrene resins such as styrene (AS) copolymers and acrylonitrile-butadiene-styrene (ABS) copolymers; polyvinyl chloride resins such as polyvinyl chloride and vinylidene chloride; polyphenylene sulfides; polyether sulfone, polyether ketones , Polyether-based resins such as polyether ether ketones. These can be used individually by 1 type or in combination of 2 or more types.

Among these thermoplastic resins, it is preferable to use a polyolefin resin, an aromatic polyester resin, or an aliphatic polyester resin from the viewpoints of ease of molding, performance, economy, and the like.

Here, the polyolefin-based resin is a polyolefin-based resin containing an olefin component unit as a main component, and specifically, as described above, polypropylene-based resin, polyethylene-based resin, other polymethyl-1-pentene, ethylene- Examples thereof include cyclic olefin copolymers and the like, as well as mixtures of two or more of them. The above-mentioned "main component" means that the polyolefin component unit contains 50% by mass or more of the olefin component unit, and the content thereof is preferably 75% by mass or more, more preferably 85% by mass. % Or more, more preferably 90% by mass or more. The method for producing the polyolefin resin used in the present invention is not particularly limited, and can be obtained by any of a method using a Ziegler-Natta catalyst, a metallocene catalyst, a radical initiator such as oxygen or peroxide, or the like. It may be a catalyst.

Examples of the polypropylene-based resin include resins having a propylene component unit of 50% by mass or more, and examples thereof include a propylene homopolymer and a copolymer with another α-olefin copolymerizable with propylene. Other α-olefins that can be copolymerized with propylene include, for example, ethylene, 1-butene, isobutylene, 1-pentene, 3-methyl-1-butene, 1-hexene, and 3,4-dimethyl-1-butene. , 1-Heptene, 3-Methyl-1-hexene and the like, α-olefins having 4 to 10 carbon atoms are exemplified. Propylene homopolymers include any of isotactics, syndiotactics, atactics, hemiisotactics and linear or branched polypropylenes exhibiting various stereoregularities. Further, the above-mentioned copolymer may be a random copolymer or a block copolymer, and may be not only a binary copolymer but also a ternary copolymer. Specifically, for example, ethylene-propylene random copolymer, butene-1-propylene random copolymer, ethylene-butene-1-propylene random ternary copolymer, ethylene-propylene block copolymer and the like can be exemplified. ..

Examples of the polyethylene-based resin include resins having an ethylene component unit of 50% by mass or more. For example, high-density polyethylene (HDPE), low-density polyethylene (LDPE), medium-density polyethylene, and linear low-density polyethylene ( LLDPE), ethylene-vinyl acetate copolymer, ethylene-propylene copolymer, ethylene-propylene-butene 1 copolymer, ethylene-butene 1 copolymer, ethylene-hexene 1 copolymer, ethylene-4 methylpentene 1 Examples thereof include a copolymer, an ethylene-octene 1 copolymer, and a mixture of two or more of them.

Among the above-mentioned polyolefin resins, polypropylene resins are preferably used because they are particularly excellent in the balance between mechanical strength and heat resistance.

(Inorganic powder)
As described above, when the base material is an inorganic substance powder-blended thermoplastic plastic sheet, the inorganic substance powder that can be blended in the sheet is not particularly limited, and is, for example, calcium, magnesium, aluminum, titanium, iron. , Zinc and other carbonates, sulfates, silicates, phosphates, borates, oxides, or powders of hydrates thereof. Specific examples thereof include calcium carbonate and carbonic acid. Magnesium, zinc oxide, titanium oxide, silica, alumina, clay, talc, kaolin, aluminum hydroxide, magnesium hydroxide, aluminum silicate, magnesium silicate, calcium silicate, aluminum sulfate, magnesium sulfate, calcium sulfate, magnesium phosphate, barium sulfate , Silica sand, carbon black, zeolite, molybdenum, diatomaceous soil, sericite, silas, calcium sulfate, sodium sulfate, potassium titanate, bentonite, graphite and the like. These may be synthetic or derived from natural minerals, and they may be used alone or in combination of two or more.

Further, the shape of the inorganic substance powder is not particularly limited, and may be in the form of particles, flakes, granules, fibers, or the like. Further, the particles may be spherical as generally obtained by a synthetic method, or may have an indefinite shape as obtained by pulverizing a natural mineral.

As these inorganic substance powders, calcium carbonate, magnesium carbonate, zinc oxide, titanium oxide, silica, alumina, clay, talc, kaolin, aluminum hydroxide, magnesium hydroxide and the like are preferable, and calcium carbonate is particularly preferable. Further, the calcium carbonate is either so-called light calcium carbonate prepared by a synthetic method or so-called heavy calcium carbonate obtained by mechanically crushing and _{classifying a natural raw material containing CaCO 3 as a main component such as limestone.} It may be present, and it is possible to combine these, but from the viewpoint of economy, heavy calcium carbonate is preferable.

Here, heavy calcium carbonate is obtained by mechanically crushing and processing natural limestone or the like, and is clearly distinguished from synthetic calcium carbonate produced by a chemical precipitation reaction or the like. The pulverization method includes a dry method and a wet method, but the dry method is preferable from the viewpoint of economy.

Further, in order to enhance the dispersibility or reactivity of the inorganic substance powder, the surface of the inorganic substance powder may be surface-modified in advance according to a conventional method. Examples of the surface modification method include a physical method such as plasma treatment and a method of chemically surface-treating the surface with a coupling agent or a surfactant. Examples of the coupling agent include a silane coupling agent and a titanium coupling agent. The surfactant may be anionic, cationic, nonionic or amphoteric, and examples thereof include higher fatty acids, higher fatty acid esters, higher fatty acid amides and higher fatty acid salts.

The inorganic substance powder is preferably particles, and the average particle size is preferably 0.1 μm or more and 50.0 μm or less, more preferably 1.0 μm or more and 10.0 μm or less, and further preferably 1.0 μm or more and 5.0 μm or less. preferable. Unless otherwise specified, the average particle size of the inorganic substance powder described in the present specification means a value calculated from the measurement result of the specific surface area by the air permeation method according to JIS M-8511. As the measuring device, for example, a specific surface area measuring device SS-100 manufactured by Shimadzu Corporation can be preferably used. In particular, it is preferable that the particle size distribution does not contain particles having a particle size exceeding 50.0 μm. On the other hand, if the particles become too fine, the viscosity will be significantly increased when kneaded with the above-mentioned thermoplastic resin, which may make it difficult to manufacture a molded product. Therefore, the average particle size is preferably 0.5 μm or more.

The inorganic substance powder may be in the form of fibers, powders, flakes, or granules.

The average fiber length of the fibrous inorganic substance powder is preferably 3.0 μm or more and 20.0 μm or less. The average fiber diameter is preferably 0.2 μm or more and 1.5 μm or less. The aspect ratio is usually 10 or more and 30 or less. The average fiber length and average fiber diameter of the fibrous inorganic substance powder were measured with an electron microscope, and the aspect ratio was the ratio of the average fiber length to the average fiber diameter (average fiber length / average fiber diameter). Is.

When the base material is an inorganic substance powder-blended thermoplastic sheet as described above, the blending ratio (mass%) of the above-mentioned thermoplastic resin contained therein and the inorganic substance powder is as described above. The ratio is preferably 50:50 to 10:90, more preferably 40:60 to 20:80, and even more preferably 40:60 to 25:75. When the proportion of the inorganic substance powder is lower than 50% by mass in the blending ratio of the thermoplastic resin and the inorganic substance powder, the predetermined texture of the inorganic substance powder blended thermoplastic resin composition due to the blending of the inorganic substance powder. This is because physical properties such as impact resistance cannot be obtained, while if it is higher than 90% by mass, molding processing by extrusion molding, vacuum molding, or the like becomes difficult.

(Other additives)
Further, when the base material is the plastic sheet or the thermoplastic plastic sheet containing the inorganic substance powder, it is possible to add other additives as an auxiliary agent in the composition, if necessary. is there. Other additives include, for example, plasticizers, colorants, lubricants, coupling agents, fluidity improvers, dispersants, antioxidants, UV absorbers, flame retardants, stabilizers, antistatic agents, foaming agents and the like. Can be mentioned. These additives may be used alone or in combination of two or more.

(Paper material)
Specific examples of the case where the base material is composed of a paper-based material include a paper base material such as glassin paper, coated paper, wood-free paper, dust-free paper, and impregnated paper, and a thermoplastic resin such as polyethylene on the above paper base material. Examples thereof include laminated paper in which the above is laminated.

(Base material composition)
The base material may be composed of a single sheet made of the above-mentioned material, or a plurality of layers may be laminated to form a base material. When the base material is the plastic sheet or the thermoplastic plastic sheet containing inorganic substance powder, the sheet may be unstretched or stretched in the uniaxial direction or the biaxial direction such as vertical or horizontal. It may be the one that has been done.

The thickness of the base material is not particularly limited, but is usually 10 μm or more and 400 μm or less, preferably 25 μm or more and 350 μm or less.

Further, when a base material made of a plastic sheet or a thermoplastic plastic sheet containing the inorganic substance powder is used, it is oxidized on one side or both sides as desired for the purpose of improving the adhesion to the coat layer provided on the surface thereof. Surface treatment can be performed by a method, an unevenness method, or the like. Examples of the oxidation method include corona discharge treatment, frame treatment, plasma treatment, glow discharge treatment, chromic acid treatment (wet), flame treatment, hot air treatment, ozone / ultraviolet irradiation treatment, and the like. For example, a sandblasting method, a solvent treatment method, and the like can be mentioned. It is also possible to apply a primer treatment.

(2) Coat layer The coat layer of the antibacterial printing sheet of the present invention may be provided on only one side of the base material or on both sides. The thickness of this coat layer is not particularly limited, but is preferably 1 μm or more and 10 μm or less, more preferably 2 μm or more and 8 μm or less, and particularly preferably 3 μm or more and 5 μm or less. preferable. If the thickness is within this range, the coat layer (and the printing ink layer attached thereto) exhibits sufficient antibacterial properties, and also functions sufficiently as an ink receiving layer to provide good colorability and color development. In addition to exhibiting ink receiving characteristics such as, the characteristics such as water resistance of the printing sheet, antistatic property on the surface, and adhesion to ink are also good.

Thus, in the present invention, in this coat layer, zinc pyrithione is 0.40% by mass or more and 2.00% by mass or less, more preferably 0.50% by mass or more in the continuous phase of the acrylic polymer serving as a matrix. 50% by mass or less, more preferably 0.60% by mass or more and 1.40% by mass or less, zinc oxide 0.10% by mass or more and 1.00% by mass or less, more preferably 0.12% by mass or more and 0.80% by mass. % Or less, more preferably 0.15% by mass or more and 0.60% by mass or less, clay 30% by mass or more and 50% by mass or less, more preferably 30% by mass or more and 45% by mass or less, still more preferably 35% by mass or more and 40. In a proportion of mass% or less, calcium carbonate is added in a proportion of 10% by mass or more and 30% by mass or less, more preferably 15% by mass or more and 30% by mass or less, and further preferably 20% by mass or more and 25% by mass or less. Is.

Zinc pyrithione, zinc oxide, clay, and calcium carbonate are present in a well-balanced amount in the above-mentioned predetermined amounts in the continuous phase made of the acrylic polymer in the coat layer, so that the printing sheet exhibits excellent antibacterial properties and is water resistant. The properties and whiteness are maintained at the desired level, and the weather resistance is also improved. Further, the resistivity, particularly the surface resistivity, is lowered, and it becomes possible to transfer the toner without applying a high voltage when performing LBP printing, for example. Oil resistance is also improved, ink quick-drying is improved, and oil-based offset printing suitability is improved.

If the amount of zinc pyrithione blended in this coat layer is less than the above range, sufficient antibacterial properties cannot be obtained. On the other hand, even if the blending amount of zinc pyrithione is increased from the above range, the antibacterial property is not necessarily improved, and the bleeding of zinc pyrithione to the interface becomes large, so that the adhesiveness between the coat layer and the base material and the printing ink layer becomes large. May decrease.

Further, if the blending amounts of zinc oxide, clay, and calcium carbonate in this coat layer are out of the above range, even if zinc pyrithione is blended in an appropriate amount, it does not sufficiently bleed or migrate to the surface of the coat layer or the printing ink layer. The desired antibacterial properties may not be exhibited. If the blending amount of these fillers is out of the above range, the appearance of the coat layer such as adhesion to the base material and printing ink layer, toner transferability, water resistance, oil resistance offset suitability, and whiteness will be adversely affected. In some cases.

The coat layer of the antibacterial printing sheet of the present invention is formed by blending a specific filler together with zinc pyrithione in a predetermined blending ratio as described above. By appropriately adjusting the amount and particle size, and the thickness of the coat layer to be formed, the surface of the coat layer can be made matte with a certain degree of roughness, or glossy with increased glossiness. It is also possible to.

Hereinafter, each component forming the coat layer of the present invention will be described in detail.

(Acrylic polymer forming a continuous phase)
The acrylic polymer serving as the matrix of the coat layer includes (meth) acrylic acid, (meth) acrylic acid ester, (meth) acrylamides, and a polymer obtained by using (meth) acrylonitrile as a main monomer component. The term "(meth) acrylic" used in the present specification is used to include both "acrylic" and "methacryl".

More specifically, the monomer component constituting the acrylic polymer is not particularly limited, but is not limited.
Acrylic acid, methacrylic acid;
For example, methyl acrylate, ethyl acrylate, n-propyl acrylate, isopropyl acrylate, n-butyl acrylate, isobutyl acrylate, t-butyl acrylate, hexyl acrylate, n-octyl acrylate, -2 acrylate. -Acrylic acid alkyl ester having 1 to 18 carbon atoms in an alkyl group such as ethylhexyl, isooctyl acrylate, nonyl acrylate, lauryl acrylate, stearyl acrylate, palmityl acrylate or cyclohexyl acrylate;
For example, methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, isopropyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, t-butyl methacrylate, hexyl methacrylate, n-octyl methacrylate, isooctyl methacrylate, Alkyl methacrylate having 1 to 18 carbon atoms in alkyl groups such as -2-ethylhexyl methacrylate, nonyl methacrylate, lauryl methacrylate, stearyl methacrylate, palmityl methacrylate and cyclohexyl methacrylate;
For example, 2-hydroxymethyl acrylate, 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl acrylate, 2-hydroxypropyl methacrylate, 4-hydroxybutyl acrylate, 4-hydroxybutyl methacrylate. , Alkyl ester having a hydroxyl group on the side chain of (meth) acrylic acid such as monohydroxyethyl acrylate phthalate;
For example, polyethylene glycol having an ethylene glycol unit in the molecule (n is preferably 3 or more and 20 or less) diacrylate, trimethylolpropane EO modification (n is preferably 3 or more and 20 or less) triacrylate, phenol EO modification (n). Is preferably 3 or more and 20 or less.) Acrylate,
For example, alkenyloxyalkyl esters of (meth) acrylic acids such as allyloxyethyl acrylate and allyloxyethyl methacrylate,
For example, an alkyl ester having an alkoxyl group on the side chain of (meth) acrylic acid such as methoxybutyl acrylate, methoxybutyl methacrylate, methoxyethyl acrylate, methoxyethyl methacrylate, ethoxybutyl acrylate, and ethoxybutyl methacrylate;
For example, alkenyl esters of (meth) acrylic acids such as allyl acrylate and allyl methacrylate;
For example, glycidyl acrylate, glycidyl methacrylate, and alkyl esters having an epoxy group on the side chain of acrylic acid such as methyl glycidyl acrylate and methyl glycidyl methacrylate;
For example, mono- or di-alkylaminoalkyl esters of (meth) acrylic acids such as diethylaminoethyl acrylate, diethylaminoethyl methacrylate, methylaminoethyl acrylate, methylaminoethyl methacrylate;
For example, a silicone-modified (meth) acrylic acid ester having a silyl group, an alkoxysilyl group, a hydrolyzable alkoxysilyl group, or the like as a side chain;
For example, acrylamide, methacrylamide;
For example, (meth) acrylamide having a methylol group such as N-methylolacrylamide and N-methylolmethacrylamide;
For example, (meth) acrylamide having an alkoxymethylol group such as N-alkoxymethylolacrylamide (eg, N-isobutoxymethylolacrylamide) and N-alkoxymethylolmethacrylamide (eg, N-alkoxymethylolmethacrylamide, etc.);
For example, (meth) acrylamide having an alkoxyalkyl group such as N-butoxymethylacrylamide or N-butoxymethylmethacrylamide; and
Various acrylic monomers such as acrylonitrile and methacrylonitrile can also be mentioned as monomer components constituting the acrylic resin.
Further, when a crosslinked structure is introduced into the acrylic polymer by a photocuring reaction or the like to increase the film strength of the coat layer, a bifunctional or polyfunctional acrylic monomer, specifically, for example, 1, 4-Butandiol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, neopentyl glycol di (meth) acrylate, the above polyethylene glycol di (meth) acrylate, neopentyl glycol di (meth) hydroxypivalate. Acrylate, dicyclopentanyldi (meth) acrylate, caprolactone-modified dicyclopentenyldi (meth) acrylate, ethylene oxide-modified di (meth) acrylate, allylated cyclohexyldi (meth) acrylate, isocyanurate di (meth) acrylate, Trimethylol propantri (meth) acrylate, dipentaerythritol tri (meth) acrylate, propionic acid-modified dipentaerythritol tri (meth) acrylate, pentaerythritol tri (meth) acrylate, propylene oxide-modified trimethylol propanthry (meth) acrylate, Tris (acryloxyethyl) isocyanurate, pentaerythritol tetra (meth) acrylate, dipentaerythritol penta (meth) acrylate, propionic acid-modified dipentaerythritol penta (meth) acrylate, dipentaerythritol hexa (meth) acrylate, caprolactone-modified di It is also possible to blend a polyfunctional (meth) acrylate such as pentaerythritol hexa (meth) acrylate.

These monomer components can be used alone or in combination of two or more.
That is, the acrylic polymer constituting the continuous phase of the coat layer in the present invention may be a homopolymer composed of only one of the various monomer components exemplified above, but the various monomer components exemplified above. A copolymer (copolymer) formed by combining a plurality of these may be used.
Further, in one embodiment of the present invention, a copolymer containing other monomer components in addition to the above-mentioned monomer components can be used as the acrylic polymer.

The monomer components other than the above examples are not particularly limited as long as they form a copolymer with the above monomer components, and for example, vinyl acetate, vinyl chloride, vinylidene chloride, vinyl lactate, vinyl butyrate, vinyl versatic acid and the like. Vinyl-based monomers such as vinyl benzoate, ethylene, butadiene, styrene and the like can be mentioned. However, it is desirable that it does not contain styrene from the viewpoint of weather resistance of the obtained sheet.

The method for forming the coat layer in the antibacterial printing sheet of the present invention is not particularly limited, but generally, from the viewpoint of coatability in forming such a coat layer. , It is desirable to use it in a form dispersed in water / or dissolved in an organic solvent, and in particular, it is desirable that it is dispersed in water, that is, in the form of an aqueous emulsion of an acrylic polymer. Therefore, it is preferable that the acrylic polymer has the form of an aqueous emulsion at the stage as a raw material for forming a coat layer.

The emulsion polymerization itself in producing an aqueous emulsion of an acrylic polymer is well known to those skilled in the art. As the surfactant used in the emulsion polymerization, anionic, cationic, amphoteric, and nonionic surfactants can be used alone or in combination of two or more. Of these, those of nonionic and cationic ones are preferable. The nonionic surfactant is not particularly limited, and examples thereof include polyoxyethylene alkyl ether, polyoxyethylene alkyl phenyl ether, polyoxyethylene alkyl ester, sorbitan alkyl ester, and polyoxyethylene sorbitan alkyl ester. is there. The cationic surfactant is not particularly limited, and examples thereof include dodecyltrimethylammonium chloride, stearyltrimethylammonium chloride, N-2-ethylhexylpyridinium chloride and the like, but the nonionic surfactant is most preferable. .. Of these, polyoxyethylene alkylphenyl ether is particularly preferable. The amount of the surfactant is not particularly limited, but usually 1 to 5% by mass of the total amount of the monomers is preferably used.

Further, a water-soluble polymer such as gelatin or polyvinyl alcohol may be used in combination as the protective colloid agent.

Examples of the radical polymerization initiator in emulsion polymerization include persulfates such as potassium persulfate and ammonium persulfate, hydrogen peroxide solution, t-butyl hydroperoxide, water-soluble types such as azobisamidinopropane hydrochloride, and benzoyl. Oil-soluble types such as peroxide, diisopropylperoxydicarbonate, cumylperoxyneodecanoate, cumylperoxyoctate, and azobisisobutyronitrile are exemplified, but water-soluble ones are preferable. The polymerization initiator is not particularly limited, but can be used, for example, in a proportion of 0.01 to 0.50% by mass of the total amount of the monomers.

The polymerization reaction is not particularly limited, but is usually carried out at a temperature of 35 to 90 ° C. under stirring, and the reaction time is usually 3 to 40 hours. Further, by adjusting the pH by adding a basic substance at the start or end of emulsion polymerization, it is possible to improve the leaving stability, freezing stability, chemical stability and the like of the emulsion. In this case, the obtained emulsion is preferably adjusted to have a pH of 5 to 9, and therefore bases such as ammonia, ethylamine, diethylamine, triethylamine, ethanolamine, triethanolamine, dimethylethanolamine, caustic soda, and caustic potash. Sexual substances can be used.

Although not particularly limited, the (meth) acrylic acid alkyl ester can be preferably exemplified as the acrylic polymer that serves as the matrix of the coat layer.

(Zinc pyrithione)
In the present invention, zinc pyrithione as an antibacterial agent is blended in the coat layer in the above ratio. Zinc pyrithione is an organozinc complex and the IUPAC name is bis (2-pyridylthio) zinc 1,1'-dioxide. It is known to have a wide sterilization spectrum and is commercially available, but any commercially available product can be used in the present invention. It may be a composite material with other substances such as inorganic powder.

In the present invention, zinc pyrithione is blended in a continuous phase of an acrylic polymer to be a matrix in combination with the following filler in a predetermined ratio. As a result, the antibacterial printing sheet of the present invention exhibits excellent antibacterial properties and printability, unlike a sheet having a coat layer containing only zinc pyrithione.

(Zinc oxide)
In the present invention, the coat layer contains zinc oxide as one of the fillers. As shown in Examples described later, the content of zinc oxide enhances the antibacterial property caused by zinc pyrithione, and the antibacterial printing sheet of the present invention exhibits an excellent antibacterial effect.

The zinc oxide used in the present invention is not particularly limited, and known zinc oxide can be appropriately used. For example, 1 type (purity 99.5% or more), 2 types (purity 99.5% or more), 3 types (purity 99.0% or more) of zinc oxide specified in JIS K 1410-1995, fine particle size. Active zinc oxide and the like (about 0.1 μm or less) can be used, but the present invention is not limited thereto. Products supplied in the form of a mixture with zinc pyrithione described above can also be used. The shape and particle size are not particularly limited, and for example, a powder having a volume average particle size of 0.05 μm or more and 10 μm or less, particularly 0.1 μm or more and 5 μm or less, and further 0.5 μm or more and 2 μm or less can be used. By using zinc oxide having such a particle size in combination, the antibacterial effect caused by zinc pyrithione can be further enhanced.

(Clay)
In the present invention, clay is also added to the continuous phase of the acrylic polymer to be the matrix in a predetermined ratio as a further filler.

The clay used in the present invention is not particularly limited, and known clays can be appropriately used. In addition, in this specification, "clay" includes not only clay minerals having a layered structure but also clay minerals having no layered structure such as imogolite and allophane. Clay minerals with a layered structure include smectite, vermiculite, montmorillonite, bentonite, illite, hectrite, haloysite, saponite, biderite, stephensite, nontronite, smectite, mica, brittle mica, sericite (sericite), Swelling minerals such as illite, gloconite (sea green stone), hydrotalcite; kaolin mineral (kaolinite, Koryo stone), serpentine, pyrophyllite, talc (talc), chlorite (green mudstone), zeolite ( Non-swelling minerals such as boiled stone), etc. can be mentioned. Examples of such clays include natural clays, synthetic clays, and organic clays.

The organic clay is not particularly limited, and any known clay can be included, but it is preferable that the clay is organicized by an organicizing agent. The clay before being organicized is not particularly limited, and any so-called clay mineral may be used, and any clay as exemplified above may be used. Moreover, such clay may be a natural product or a synthetic product.

The organic agent is not particularly limited, and a known organic agent capable of organicizing clay can be appropriately used. For example, hexylammonium ion, octylammonium ion, and 2-ethylhexylammonium ion can be used. , Dodecyl ammonium ion, lauryl ammonium ion, octadecyl ammonium ion, dioctyl dimethyl ammonium ion, trioctyl ammonium ion, dioctadecyl dimethyl ammonium ion, trioctyl ammonium ion, dioctadecyl dimethyl ammonium ion, trioctadecyl ammonium ion and the like can be used. ..

The clay used in the present invention is not particularly limited, but kaolin clay is particularly preferable from the viewpoint of uniform dispersibility in the coat layer.

The particle size of this clay is not particularly limited and depends to some extent on the thickness of the coat layer to be formed. For example, the volume average particle size is 0.05 μm or more and 2.00 μm or less. , More preferably 0.1 μm or more and 1.5 μm or less, and further preferably 0.5 μm or more and 1.0 μm or less. With such a particle size range, clay can be blended in the formed coat layer with good dispersibility, and the above-mentioned improvements in substrate adhesiveness, printability, and antistatic performance are expected. The effect of zinc pyrithione can be more preferably exhibited, and the antibacterial effect caused by zinc pyrithione can be further enhanced.

The shape of the clay is not particularly limited, and may be any of a spherical shape, an elliptical spherical shape, a flat shape, an indefinite shape, and the like.

Further, as clay, it is desirable that the particle size between the particles is uniform in order to make the in-plane characteristics of the coat layer uniform.

Further, the specific gravity of the clay is not particularly limited, but is, for example, 1.5 to 3.0, more preferably 2.0 to 2.8 for the entire coat layer to be formed. It is desirable because it can be uniformly dispersed.

(Calcium carbonate)
In the present invention, the coat layer contains calcium carbonate as a filler together with zinc oxide and clay. In the present invention, excellent antibacterial properties derived from zinc pyrithione are exhibited by using calcium carbonate together with the above-mentioned filler. By blending calcium carbonate, it is possible to smooth the coat layer and maintain an appropriate luster.

The calcium carbonate used in the present invention is not particularly limited, and for example, the calcium carbonate exemplified as the raw material for the above-mentioned base material can be used. The particle size is not particularly limited, but for example, the volume average particle size is preferably 0.05 μm or more and 2.00 μm or less, and particularly preferably 0.07 μm or more and 1.50 μm or less. With such a particle size range, the antibacterial effect caused by zinc pyrithione can be made more remarkable, and the whiteness desired for a printing sheet, the smoothness of the coat layer, and the sheet The glossiness can be improved.

(Other additives)
In the present invention, the coat layer may contain other components such as additives other than the above.
Specific examples of the additive include a cross-linking agent, a pH adjuster, a thickener, a fluidity improver, a defoamer, a defoaming agent, a surfactant, a mold release agent, a penetrant, a coloring pigment, and a coloring dye. , Fluorescent whitening agent, ultraviolet absorber, antioxidant, preservative, fungicide, water resistant agent, ink fixing agent, curing agent, weather resistant agent and the like.

Examples of the cross-linking agent include aldehyde compounds, melamine compounds, isocyanate compounds, zirconium compounds, titanium compounds, amide compounds, aluminum compounds, boric acid, borates, carbodiimide compounds, oxazoline compounds and the like. Be done.

Further, it is preferable that the ink fixing agent contains a cationic resin other than the acrylic resin or a polyvalent metal salt. Examples of the cationic resin include polyethyleneimine-based resin, polyamine-based resin, polyamide-based resin, polyamide epichlorohydrin-based resin, polyamine epichlorohydrin-based resin, polyamide polyamine epichlorohydrin-based resin, polydialylamine-based resin, and dicyandiamide condensate. Examples of the polyvalent metal salt include calcium compounds, magnesium compounds, zirconium compounds, titanium compounds, aluminum compounds and the like. Among these, calcium compounds are preferable, and calcium nitrate tetrahydrate is more preferable.

The defoaming agent is not particularly limited, but for example, a mineral oil-based defoaming agent, a polyether-based defoaming agent, or a silicone-based defoaming agent is used, and a mineral oil-based defoaming agent is preferable. The hydrophobic silica type mineral oil-based defoaming agent is not limited to the following, and is, for example, Nopco 8034, Nopco 8034-L, SN Deformer AP, SN Deformer H-2, SN Deformer TP-33, SN Deformer VL, SN Deformer 113, SN Deformer 154, SN Deformer 154S, SN Deformer 313, SN Deformer 314, SN Deformer 316, SN Deformer 317, SN Deformer 318, SN Deformer 319, SN Deformer 321 and SN Deformer 323, SN Deformer 364, SN Deformer 414, SN Deformer 456, SN Deformer 474, SN Deformer 476-L, SN Deformer 480, SN Deformer 777, SN Deformer 1341, SN Deformer 1361 (all manufactured by Sannopco), BYK-1740 (BYK) (Manufactured by the company) etc. are commercially available. The metal soap type mineral oil defoamer is not limited to the following, but is, for example, Nopco DF-122, Nopco DF-122-NS, Nopco NDW, Nopco NXZ, SN Deformer 122-SV. , SN Deformer 269, SN Deformer 1010 (all of which are manufactured by San Nopco Ltd.) and the like are commercially available. The amide wax type mineral oil defoaming agent is not limited to the following, but is, for example, Nopco 267-A, Nopco DF-124-L, SN Deformer TP-39, SN Deformer 477T, SN. Deformers 477-NS, SN Deformer 479, SN Deformer 1044, SN Deformer 1320, SN Deformer 1340, SN Deformer 1360, and SN Deformer 5100 (all of which are manufactured by Sannopco) are commercially available. Only one of these may be used alone, or two or more thereof may be used in combination. The amount of the defoaming agent used is not particularly limited, but is preferably 0.01 to 0.03% by mass with respect to the entire coating liquid forming the coat layer.

Examples of the preservative include, but are not limited to, 5-chloro-2-methyl-4-isothiazolin-3-one and 2-methyl-2H-isothiazole-3-one. It is also possible to use two or more kinds of preservatives in an arbitrary ratio.

The coat layer according to the present invention can be added with respect to fillers other than the above-mentioned zinc oxide, clay, and calcium carbonate as long as the above-mentioned excellent effects are not impaired, but other fillers thereof. Is substantially free, for example, it is desirable that it is 10% by mass or less, particularly 5% by mass or less of the total mass of the coat layer. The inclusion of other fillers may inhibit the bleed-based antibacterial properties of zinc pyrithione. In particular, for example, it is desirable that polymer fine particles such as (meth) acrylic acid ester-based resin particles typified by polymethylmethacrylate particles are not substantially contained.

Further, in the preparation of the coating liquid for forming the coat layer, for example, when an acrylic polymer aqueous emulsion is used as the acrylic polymer serving as the matrix of the coat layer, the filler or its water or the like is used. The dispersion is added to water, which is a dispersion medium of an aqueous emulsion of an acrylic polymer, and a rotation condition of 500 to 3000 rpm is used using a suitable stirrer or disperser, for example, a wet colloid mill, an edged turbine, a paddle blade, or the like. This can usually be done by dispersing for 1 to 5 minutes. If the filler is added to the aqueous emulsion of the acrylic polymer as it is, aggregation may occur. Therefore, a dispersant is mixed in advance as necessary to disperse the filler in a medium such as water. May be blended in an aqueous emulsion of an acrylic polymer.

<Manufacturing method of antibacterial printing sheet>
As a method for producing the antibacterial printing sheet of the present invention, a method of forming a coat layer on the surface of a known base material can be used. 40% by mass or more and 2.00% by mass or less, zinc oxide is 0.10% by mass or more and 1.00% by mass or less, clay is 30% by mass or more and 50% by mass or less, and calcium carbonate is 10% by mass or more and 30% by mass or less. A coating liquid consisting of an acrylic polymer aqueous emulsion mixed in a proportion is applied by an appropriate method such as roll coating, blade coating, bar coating, brush coating, spray coating, dipping, etc., and then the coating layer is applied. It can be done by drying and curing. The temperature conditions for drying or curing the coat layer are not particularly limited, but may be, for example, a temperature of 90 to 120 ° C.

In the embodiment in which the above-mentioned sheet made of the inorganic substance powder-blended thermoplastic plastic is used as the base material, for example, a base material containing a polyolefin resin and the inorganic substance powder in a mass ratio of 50:50 to 10:90. Is extruded into a sheet and stretched, and on one or both sides of the base sheet, zinc pyrithione is 0.40% by mass or more and 2.00% by mass or less and zinc oxide is 0.10% by mass or more in terms of dry mass. An appropriate coating liquid consisting of an acrylic polymer aqueous emulsion containing 1.00% by mass or less, clay in an amount of 30% by mass or more and 50% by mass or less, and calcium carbonate in a proportion of 10% by mass or more and 30% by mass or less. This can be done by coating by method and then drying and curing the coat layer. Inorganic substance powder blending In molding a sheet made of thermoplastic, the mixture of the inorganic substance powder and the polyolefin resin can be done even if the polyolefin resin and the polyolefin resin are kneaded and melted before being put into the molding machine from the hopper. It is preferable that the polyolefin resin and the inorganic substance powder may be kneaded and melted at the same time as molding by a molding machine. The same applies to other additives other than the inorganic substance powder. Further, in the melt kneading, it is preferable to knead the polyolefin resin by applying a high shear stress while uniformly dispersing the inorganic substance powder, and it is preferable to knead the mixture with, for example, a twin-screw kneader. When the above inorganic substance powder is blended with a polyolefin resin, the higher the temperature, the more odor tends to be generated. Therefore, the melting point of the polyolefin resin is + 55 ° C. or lower, preferably the melting point of the polyolefin resin or higher and the melting point is + 55 ° C. or lower. More preferably, the treatment is carried out at a temperature of the polyolefin resin having a melting point of +10 ° C. or higher and the thermoplastic resin having a melting point of + 45 ° C. or lower.
The molding temperature at the time of extrusion molding into a sheet is preferably the same temperature.

Further, the stretching treatment when molding into a sheet shape is not particularly limited, and is uniaxially or biaxially or multiaxially (stretching by the tubular method, etc.) at the time of molding or after molding. It is possible to stretch to. In the case of biaxial stretching, sequential biaxial stretching or simultaneous biaxial stretching may be used.

When the molded sheet is stretched (for example, longitudinally and / or laterally stretched), the density of the sheet decreases. As the density decreases, the whiteness of the sheet becomes good.

Hereinafter, the present invention will be described in more detail based on Examples. It should be noted that these examples are specific embodiments and embodiments for facilitating the understanding of the concept and scope of the present invention disclosed in the present specification and described in the appended claims. The present invention is described only for the purposes of the examples of the above, and the present invention is not limited to these examples.

(Evaluation method)
Each physical property value in the following Examples and Comparative Examples was evaluated by the following method.

(Antibacterial)
Antibacterial properties against Escherichia coli and Staphylococcus aureus were measured according to ISO22196 (JIS Z2801).
The viable cell count after inoculating Escherichia coli or Staphylococcus aureus into each sample after printing or before printing, which will be described later, and leaving it for 24 hours under the same conditions, and the viable cell count of the reference sample (blank) after leaving it for 24 hours under the same conditions. The difference from the above was taken as the antibacterial activity value of each sample against each bacterium. Samples with an antibacterial activity value of 2 or more were judged to be acceptable products.

(Anti-virus)
The antibacterial property against influenza virus was measured according to ISO21702.
The difference between the virus infectious titer after inoculating the virus into each sample after printing or before printing and leaving it for 24 hours and the virus infectious titer of the reference sample (blank) after leaving it for 24 hours under the same conditions, which will be described later. , The anti-virus activity value of each sample was used. A sample having an anti-virus activity value of 2 or more was judged as a passing product.

(LBP printability)
In order to check the LBP printability of printing sheets, color and monochrome test patterns are printed on each sheet with a laser printer (product name: Versant 80 Press, manufactured by Fuji Xerox Co., Ltd.), and toner fixability. Was visually observed, and the printability was evaluated based on the following evaluation criteria.
-Evaluation criteria ○ The test pattern is printed neatly, and there is no toner peeling.
△ The test pattern is printed well, but the toner is slightly peeled off.
× The test pattern is not printed well, and toner peeling is significant.

(Offset printing suitability)
In order to check the offset printing suitability of printing sheets, a test pattern was printed on each sheet using UV offset ink with an offset printing machine (product name: RMGT920, manufactured by Ryobi MHI Graphic Technology Co., Ltd.). The fillability and ink fixability were visually observed, and the offset printing suitability was evaluated based on the following evaluation criteria.
-Evaluation criteria ○ The test pattern is printed neatly, and there is no poor inking or ink peeling.
△ The test pattern is printed well, but poor inking and some ink peeling occur.
× The test pattern is not printed well, and the inking is poor and the ink is peeled off significantly.

(material)
The components used in the following examples and comparative examples were as follows.

Substrate S1: 36.0 parts by mass of polypropylene homopolymer (melting point 160 ° C.) and calcium carbonate with an average particle size of 2.2 μm (average particle size by air permeation method according to JIS M-1511) as an inorganic substance powder. Extrusion molding machine (T-die extrusion molding device) equipped with a twin-screw screw containing 60.0 parts by mass of particles and 2.0 parts by mass of sodium alkanesulfonate (alkyl group carbon number (average value) = 12) as a lubricant. It is put into φ20 mm, L / D = 25) and kneaded at a temperature of 220 ° C. or lower, and the kneaded raw material is sheet-molded by a T-die at a molding temperature of 220 ° C. and stretched while being wound by a take-up machine to become a base material. A sheet made of a thermoplastic containing an inorganic substance powder was prepared. The wall thickness of the sheet thus obtained was 200 μm.

-Acrylic polymer: contains n-butyl acrylate, methyl methacrylate, 2-ethylhexyl acrylate, methacrylic acid, vinyl acetate, and rosin derivative in a mass ratio of 26:16:44: 8: 6: 3. Aqueous emulsion of (meth) acrylic acid alkyl ester copolymer (solid content: water = 50:50 (mass ratio))
-Zinc pyrithione-Zinc oxide: Volume average particle size 0.75 μm
-Clay: Kaolin ray (volume average particle size 0.29 μm, specific gravity 2.6)
-Calcium carbonate particles: Heavy calcium carbonate (volume average particle size 0.34 μm, specific gravity 2.6)
・ Dispersant: Sodium polyacrylate ・ Thickener: Starch ・ Defoamer: Hydrophobic silica type mineral oil defoamer

[Examples 1 to 3 and Comparative Examples 1 to 2]
The above acrylic polymer aqueous emulsion, zinc pyrithione, zinc oxide, clay, and calcium carbonate are each blended in the addition amounts (solid content) shown in Table 1 below, and stirred and mixed at 3000 rpm for 3 minutes using an edged turbine. , A coating layer coating solution was prepared. The amount of each raw material added shown in Table 1 is a value in terms of dry mass of the coating layer coating liquid. In any of the coating layer coating liquids, water was used as the dispersion medium, and the solid content concentration was about 55% by mass. Further, in each of the coating layer coating liquids, about 0.2% by mass of the dispersant, about 0.5% by mass of the thickener, and about 0.1% by mass of the defoaming agent were blended. Thickeners and antifoaming agents are not essential components, and it was possible to prepare a coating layer coating liquid without adding them. The coat layer coating liquid prepared in this manner is applied to both sides of the above-mentioned base material by the microgravure method so that the coating ^{amount after drying is 4 g / m 2 each, and dried at 110 ° C.} And created a printing sheet. The LBP printability and offset printability of each of the obtained printing sheets were evaluated by the above method. Then, the antibacterial property and the antiviral property of each of these sheets after printing or before printing were evaluated by the above method. The results obtained are shown in Table 1.

From Examples 1 to 3, the antibacterial printing sheet having a coat layer in which zinc pyrithione, zinc oxide, clay, and calcium carbonate are blended in a specified amount in a continuous phase made of an acrylic polymer according to the present invention is in a blank state. It was clarified that excellent antibacterial and antiviral properties were exhibited both (before printing) and after printing by various methods. On the other hand, in Comparative Example 1 in which the coat layer did not contain zinc pyrithione, antibacterial properties were not exhibited. Further, in Comparative Example 2 in which the coat layer contained 3% by mass or more of zinc pyrithione, although there was no problem in antiviral property, zinc pyrithione excessively bleeded on the surface of the printing sheet, resulting in poor printability. On the other hand, the antibacterial printing sheets of Examples 1 to 3 in which the coat layer satisfies the provisions of the present invention all showed good printability.

[Example 3, Comparative Examples 3 to 6]
The content of each filler in the coat layer varied as shown in Table 2, and talc (average particle size: 3.3 μm) was used instead of clay to perform the same test as in Example 3. .. The test results are shown in Table 2. The contents in Table 2 are all values of mass% based on the solid content.

The sheet of Example 3 having the coating layer of the formulation specified in the present invention had good antibacterial / antiviral properties and printability, whereas the sheet of Comparative Example 3 containing no zinc oxide had antibacterial properties. -Insufficient antiviral properties. Even in the sheets of Comparative Examples 4 and 5 in which the content of clay and calcium carbonate is outside the specification of the present invention and Comparative Example 6 in which talc is used instead of clay, either antibacterial / antiviral property or printability is poor. Met. It was shown that if the content of not only zinc pyrithione but also the filler deviates from the formulation specified in the present invention, an antibacterial printing sheet having excellent antibacterial / antiviral properties and printability cannot be obtained. ..

Claims (7)

An antibacterial printing sheet having a coat layer containing an acrylic polymer on one side or both sides of a base material.
When the total mass of the coat layer is 100% by mass,
Zinc pyrithione is blended in a continuous phase made of the acrylic polymer in a proportion of 0.40% by mass or more and 2.00% by mass or less.
Zinc oxide having a volume average particle diameter of 0.05 μm or more and 2.00 μm or less is blended in a proportion of 0.10% by mass or more and 1.00% by mass or less.
Clay having a volume average particle diameter of 0.05 μm or more and 2.00 μm or less is blended in a proportion of 30% by mass or more and 50% by mass or less, and
Calcium carbonate having a volume average particle size of 0.05 μm or more and 2.00 μm or less is blended in a proportion of 10% by mass or more and 30% by mass or less .
Anti-fungal printing sheet. The antibacterial printing sheet according to claim 1, wherein the base material is a base material containing a polyolefin resin and an inorganic substance powder in a mass ratio of 50:50 to 10:90. The antibacterial printing sheet according to claim 2, wherein the inorganic substance powder is calcium carbonate powder. The antibacterial printing sheet according to any one of claims 1 to 3 , wherein the acrylic polymer is a polymer of a (meth) acrylic acid alkyl ester. The (meth) acrylic acid alkyl ester is methyl acrylate, ethyl acrylate, n-propyl acrylate, isopropyl acrylate, n-butyl acrylate, isobutyl acrylate, n-octyl acrylate, -2-ethylhexyl acrylate. , Isooctyl acrylate, nonyl acrylate, methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, isopropyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, n-octyl methacrylate, -2-ethylhexyl methacrylate, A claim that is one or more selected from the group consisting of isooctyl methacrylate, 2-hydroxymethyl acrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl acrylate, and 2-hydroxypropyl methacrylate. antimicrobial printing sheet according to 4. Oxidation of zinc pyrithione by 0.40% by mass or more and 2.00% by mass or less and volume average particle size of 0.05 μm or more and 2.00 μm or less in a continuous phase made of an acrylic polymer on one side or both sides of the base material. Zinc is 0.10% by mass or more and 1.00% by mass or less, clay with a volume average particle size of 0.05 μm or more and 2.00 μm or less is 30% by mass or more and 50% by mass or less, and volume average particle size is 0.05 μm or more 2 A method for producing an antibacterial printing sheet, which comprises applying an acrylic polymer aqueous emulsion in which calcium carbonate of .00 μm or less is blended in a proportion of 10% by mass or more and 30% by mass or less. A base material containing a polyolefin resin and an inorganic substance powder in a mass ratio of 50:50 to 10:90 is extruded into a sheet, and the acrylic polymer aqueous solution is applied to one or both sides of the base material sheet through a stretching treatment step. The method for producing an antibacterial printing sheet according to claim 6 , wherein the emulsion is applied.