JPH0733892A - Antimicrobial separate sheet - Google Patents

Abstract

PURPOSE:To provide the subject sheet exhibiting a persistent antimicrobial performance excellent on hygiene because of having antibacterial and antifungal properties and showing good durability, and suitable for aseptic package by forming an antimicrobial cured coating film containing an antimicrobial agent on the surface or both the surfaces of a substrate sheet. CONSTITUTION:The objective sheet is produced by forming an antimicrobial cured coating film containing an antimicrobial agent preferably in an amount of 0.1-5wt.% on the surface or both the surfaces of a substrate sheet (preferably the sheet of a thermoplastic resin such as polyethylene or polystyrene). The antimicrobial cured coating film is preferably formed by adding the antimicrobial agent to a curable composition, coating the coating into a film-like form, and subsequently curing the coating film. The curing composition preferably comprises an acrylate prepolymer such as a poly ester acrylate. An inorganic antimicrobial agent such as zeolite containing silver ions or copper ions or zirconium phosphate is preferable as the antimicrobial agent from points such as non-toxicity for human bodies.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an antibacterial separate sheet, and more specifically, a container such as a glass bottle, a plastic bottle, or a metal can is loaded through the sheet,
The present invention relates to an antibacterial separate sheet used for bulk packaging.

[0002]

2. Description of the Related Art In the distribution of containers such as glass bottles, plastic bottles, and metal cans, it has been common to handle these containers in a carton, a wooden box, a plastic case, etc. From the viewpoint of, bulk packaging has come to be used in recent years.

[0003] In bulk packaging, typically, the first separate sheet is first placed on a pallet, and then the first-stage containers are arranged in an upright posture, and then on top of that. After placing the second separate sheet, the second-stage bottles and bottles are aligned in an upright posture, and after repeating such operations a total of n times, a separate sheet is further placed on the n-th container. It is a packing method in which the top frame is placed after placing, and then the whole including the pallet and the top frame is banded with several bands, and the whole is wrapped with a shrink film or a stretch film.

Conventionally, paperboard is mainly used as a separate sheet for use in such bulk packaging, but it has an offensive odor, cannot be washed and is unsanitary, and it is a hotbed for microbes and molds. Is unsanitary,
In addition, there was a problem that the service life was small. In recent years,
For the purpose of keeping the freshness and taste, and simplifying the process, a filling method called aseptic filling that simplifies the sterilization process has come to be adopted, and the demand for hygiene is increasing.

Regarding the plasticization of the separate sheet, JP-A-59-93692 and JP-A-01-1
No. 03439, Japanese Patent Application Laid-Open No. 01-174443,
Although disclosed in Japanese Patent Application Laid-Open No. 04-294755, it does not have antibacterial properties and cannot be used for aseptic filling.

[0006]

SUMMARY OF THE INVENTION An object of the present invention is to provide a separate sheet which solves the above-mentioned conventional problems and imparts antibacterial properties and antifungal properties.

[0007]

The inventions claimed in this application are as follows. (1) An antibacterial separate sheet having an antibacterial cured film containing an antibacterial agent formed on one or both sides of a substrate sheet. (2) The antibacterial cured film is an acrylate-based prepolymer,
The antibacterial separate sheet according to the above item 1, which is obtained by applying and curing an antibacterial curing composition containing an acrylate-based reactive monomer and the antibacterial agent as essential components.

(3) The antibacterial separate sheet according to the above item 1, wherein the content of the antibacterial agent in the antibacterial cured film is 0.1 to 5%. (4) The antibacterial separate sheet according to the above item 1, wherein the antibacterial agent is inorganic solid particles holding a metal ion having a bactericidal action. (5) The antibacterial separate sheet according to the above item 1, wherein the antibacterial cured film contains a conductive filler.

(6) The antibacterial separate sheet according to the above item 1, wherein the base material sheet is a thermoplastic resin sheet having conductivity. (7) The separate sheet according to the above item 1, wherein the cured film is an electron beam cured film. The antibacterial separate sheet of the present invention has a structure in which an antibacterial cured film is formed on one side or both sides of a base sheet.

The substrate sheet used in the present invention includes
Examples of the thermoplastic resin sheet include thick papers and non-woven fabrics, and the thermoplastic resin sheet is preferably used in consideration of hygiene at the end of the separate sheet. Examples of the thermoplastic resin sheet include, for example, polyolefin resins such as polyethylene, polypropylene and ethylene / vinyl acetate copolymers; polystyrene, acrylonitrile / butadiene / styrene copolymers, styrene resins such as acrylonitrile / styrene copolymers; poly Acrylic resin such as methylmethacrylate; 6-nylon, 66-nylon, 12
-Polyamide resin such as nylon and 6 / 12-nylon; Polyester resin such as polyethylene terephthalate and polybutylene terephthalate; Thermoplastic resin such as polyvinyl chloride resin, and a single sheet or foamed sheet made of a mixture thereof , Laminated sheets, and the like. Examples of the paper include white paperboard (manila balls, white balls, etc.), yellow paperboard, chip balls, colored paperboard, building material base paper, synthetic pulp paper made by mixing synthetic pulp and natural pulp, and the like. To be Examples of the non-woven fabric include various non-woven fabrics made of synthetic / semi-synthetic / natural fibers. The thickness of these base material sheets is determined by the application such as the type and weight of a container to be bulk-packaged, and is usually 0.5.
A thickness of about 5 mm, preferably about 7 mm, is used.

The thermoplastic resin sheet has a heat resistance stabilizer,
Weather resistance stabilizer, plasticizer, lubricant, slip agent, antistatic agent,
Charge transfer polymers, nucleating agents, flame retardants, pigments, dyes, inorganic fillers, organic fillers and the like can be added according to the purpose. Further, as the thermoplastic resin sheet,
To impart conductive performance, carbon black, metal particles, metal or metal oxide coated particles, carbon fiber, stainless steel fiber, a single body sheet containing a metal or metal oxide coated fiber, etc., if necessary, a foamed sheet, A laminated sheet may be used, or a conductive nonwoven fabric or conductive knitted fabric obtained from conductive fibers such as carbon fiber, stainless steel fiber, copper compound-coated synthetic fiber, carbon black-blended synthetic fiber, carbon black-blended composite synthetic fiber and the like. A non-woven fabric may be fused and integrated on the surface of the thermoplastic resin sheet.

In order to improve the adhesion between the base material and the conductive cured film, these base materials require surface treatment such as chemical treatment, coupling treatment, primer treatment, plasma treatment and corona discharge treatment. You may give it. The antibacterial cured film in the present invention is obtained by blending a curing composition with an antibacterial agent, and applying and curing it in a film form.

The curing composition is an epoxy resin,
Examples include polyester resins, polyurethane resins, polyamide resins, melamine resins, etc., with acryloyl group at the terminal or side chain of the molecule having polyester, epoxy, polyurethane, polyether, polyols, etc., which have particularly high radiation activity. Acrylic prepolymers such as polyester acrylates, polyepoxy acrylates, polyurethane acrylates, polyether acrylates, and polyol acrylates are preferably used.

Examples of the polyurethane acrylate prepolymer include reaction products of 2-hydroxyethyl acrylate, diisocyanate and polyol,
Examples of the diisocyanate include 2,4-tolylene diisocyanate, hexamethylene isocyanate,
Methylenephenylene diisocyanate, xylene diisocyanate, 1,4-naphthylene diisocyanate, phenylene diisocyanate and the like, and examples of the polyol include ethylene glycol, triethylene glycol, propylene glycol, 1,4-butanediol, 1,6-hexanediol, Examples include neopentyl glycol, pentaerythritol, glycerin and trimethylolpropane.

Examples of the polyester acrylate prepolymer include dehydration reaction products of acrylic acid, polybasic carboxylic acid (or anhydride) and polyol,
Examples of the polybasic carboxylic acid include trimellitic acid, pyromellitic acid, succinic acid, maleic acid, phthalic acid, itaconic acid, tetrahydrophthalic acid, hexahydrophthalic acid, and acid anhydrides thereof, adipic acid, sebacine. Acid, isophthalic acid, terephthalic acid, fumaric acid and the like, and examples of the polyol include ethylene glycol, triethylene glycol, propylene glycol,
1,4-butanediol, 1,6-hexanediol,
Examples include neopentyl glycol, pentaerythritol, glycerin and trimethylolpropane.

The epoxy acrylate prepolymer may be an addition reaction product of an epoxy compound and acrylic acid. Examples of the epoxy compound include diglycidyl phthalate, propylene glycol diglycidyl ether, vinyl cyclohexene diepoxide, and the like.
Examples include epoxidized phenol resin, epoxidized soybean oil, epoxidized polybutadiene, and bisphenol A type epoxy resin.

Further, a special acrylic prepolymer other than the above-mentioned prepolymer may be added to the curable composition of the present invention if necessary. Examples of the acrylate-based reactive monomer include trimethylolpropane triacrylate, pentaerythritol triacrylate, ethylene glycol diacrylate, triacryloxyethyl phosphate and other polyfunctional monomers, and vinylpyrrolidone, 2-hydroxylethyl (meth) acrylate. One or a mixture of two or more selected from monofunctional monomers such as, butoxyethyl acrylate, ethyldiethylene glycol acrylate, and 2-ethylhexyl acrylate.

The antibacterial agents used in the present invention include organic antibacterial agents and inorganic antibacterial agents. Organic tin compounds such as organic tin compounds, diphenyl ethers and chlorhexidines are used as the organic antibacterial agents, and suboxidants are used as the inorganic antibacterial agents. Copper, copper rhodanide, zeolite containing metal ions, zirconium phosphate, soluble glass, silica gel and the like can be mentioned, but those which do not have persistent antibacterial performance or toxicity to the human body are desirable, and silver ions or copper ions are contained. Zeolite,
Inorganic antibacterial agents such as zirconium phosphate, soluble glass and silica gel are preferably used.

The particle size of the antibacterial agent is not particularly limited, but in order to reduce the thickness of the antibacterial cured film, preferably 100 μm or less, particularly 50 μm or less. Further, these antibacterial agents are contained in the cured film in the range of 0.1 to 5% by weight. If it is less than 0.1% by weight, a sufficient antibacterial effect cannot be obtained, and if it is added in an amount of more than 5% by weight, not only the coating suitability of the curable composition is deteriorated, but also the antibacterial effect and the sustainability of No significant improvement is recognized and economic loss increases.

In the present invention, it is preferable to add a conductive filler in order to impart conductivity to the antibacterial curing composition. As the conductive filler, a metal-based conductive filler such as a metal, an alloy, a metal oxide, a composite metal oxide, or a metal-coated inorganic filler is preferably used. In addition, carbon-based materials such as carbon black, graphite, and carbon microbeads are also used. Used. The shape of the conductive filler is not particularly limited, but a shape that does not interfere with proper coating of the curable composition is preferable.

In the curing composition used in the present invention, if necessary, a photopolymerization initiator, a polymerization inhibitor, a viscosity modifier, a solvent, an antistatic agent, an ultraviolet absorber, an ultraviolet stabilizer, an antiblocking agent and a slip agent. , Leveling agents, matting agents, pigments,
Dyes, fillers, etc. may be added. For the purpose of improving the adhesiveness between the antibacterial cured film and the thermoplastic resin sheet, the antibacterial curing composition is applied to the surface of the thermoplastic resin sheet and before being cured, chemical treatment, coupling treatment, primer treatment, plasma treatment A surface treatment such as a treatment or a corona discharge treatment may be performed if necessary.

As an apparatus for applying the antibacterial curing composition,
Blade coater, knife coater, roll coater,
In addition to direct coaters, various print type coaters such as screens, offset, gravure and flexo can be used. The application of the antibacterial curing composition may be performed on the entire front and back surfaces of the separate sheet, but in consideration of sliding characteristics with a container to be loaded, economic efficiency, and designability, meshes, halftone dots, stripes, irregular systems, etc. It may be a pattern shape.

As a means for curing the antibacterial curing composition,
Room temperature curing, heating furnace, infrared irradiation, ultraviolet irradiation, electron beam irradiation, etc. In the case of electron beam irradiation, the energy required for curing is low and the productivity is good. In addition, the polymerization initiator is unnecessary, the influence of the filler on the curing is small, and even a relatively thick coating film can be cured. There is a merit of.

The electron beam irradiation is carried out in an N ₂ gas atmosphere (O ₂ concentration of 400 ppm or less) by an electron beam accelerator according to, for example, a scanning beam method or a curtain beam method. In this case, the electron beam voltage is 125 to 300 kV and the dose is about 1 to 20 Mrad.

[0025]

EXAMPLES The present invention will be specifically described below with reference to Examples and Comparative Examples, but the present invention is not limited thereto. In the examples, the antibacterial property of the separate sheet was evaluated by the following method. Method A (dripping method): A bacterial solution of bacteria (Escherichia coli, Staphylococcus aureus) conditioned in an agar medium is dripped on the surface of each sample, stored at 25 ± 5 ° C., and after 24 hours on each sample. The growth number was measured for the number of bacteria.

Method B (field evaluation): 10 cm ² from a separate sheet sample that has undergone a palletizing process to a depalletizing process to a brushing cleaning process (without a sterilizing process) in an actual line of bulk packaging (the above is referred to as an actual line process)
Was cut, shaken with sterile water, filtered, and the filter residue was cultured on an agar medium to measure the number of microorganisms. For comparison, the sample before the actual line process was similarly measured. Example 1 3% by weight of silver ion-containing soluble glass (manufactured by Ishizuka Glass Co., Ltd., ionpure, trade name) in a curable resin containing a polyester acrylate prepolymer as a main component and a particle size of 0.
50% by weight of 2 μm zinc oxide powder was mixed to obtain an antibacterial curing composition.

Next, a high-density polyethylene resin containing 20% by weight of talc as a main component has a thickness of 1.5 mm and a length of 1130.
A non-conductive separate sheet having a width of 1440 mm and a front and back surface corona-treated was obtained. The antibacterial curing composition was applied to the entire surface (one surface) of the non-conductive separate sheet at a weight per unit area of 10 g / m ² , and then an electron curtain conveyor type electron beam irradiation apparatus (Electron EPZ-2 type manufactured by ESI). ) Under N ₂ atmosphere (O ₂ concentration 2
Electron beam was irradiated at an acceleration voltage of 160 kV and a dose of 6 Mrad to form an antibacterial cured film.

Similarly, the antibacterial curing composition was applied to the other surface and cured to obtain an antibacterial separate sheet having conductivity. Examples 2 to 5, Comparative Example 1 0.05% silver-containing zeolite (Kanebo Ltd., Bactekiller, trade name) was added to a curable resin composed of polyester acrylate prepolymer, epoxy acrylate prepolymer and polyethylene glycol diacrylate. , 0.1, 0.5, 3, 5% by weight to obtain an antibacterial curing composition.

Next, a propylene-ethylene block copolymer containing 20% by weight of talc and 10% by weight of PAN-based carbon fiber having a diameter of 8 μm and a length of 6 mm (manufactured by Mitsubishi Rayon Co., Ltd., Pyrofil TRO6VBIE, trade name). As a main component, a front and back corona-treated conductive separate sheet having a thickness of 1.5 mm, a length of 1130 mm and a width of 1440 mm was obtained. The antibacterial curing composition is applied to the surface (one side) of the conductive separate sheet in a stripe shape (line width 250 μm, pitch 500 μm) at a weight of 25 g / m ² and then an electron curtain conveyor type electron beam irradiation apparatus. N ₂ by using (Electron EPZ-2 type manufactured by ESI)
Acceleration voltage 160k under atmosphere (O ₂ concentration 200ppm)
An electron beam was irradiated at V and a dose of 6 Mrad to form an antibacterial cured film.

Similarly, the antibacterial curing composition was applied to the other surface and cured to obtain an antibacterial separate sheet having conductivity. Example 6 3% of silver ion-containing zirconium phosphate (Novalon, trade name, manufactured by Toagosei Kagaku Kogyo Co., Ltd.) was mixed with a curable resin composed of a polyester acrylate prepolymer, an epoxy acrylate prepolymer and polyethylene glycol diacrylate to obtain antibacterial properties. It was a curing composition.

Next, propylene containing 20% by weight of talc.
A conductive non-woven fabric obtained from carbon black-based conductive composite fibers is fused and integrated with a molten resin film containing an ethylene block copolymer as a main component, and the thickness is 1.5 mm and the length is 113.
A corona-treated conductive separate sheet having a width of 0 mm and a width of 1440 mm was obtained. The weight of the conductive antibacterial curing composition is 25 g on the surface (one side) of the conductive separate sheet.
/ M ^{2 in} a mesh shape (line width 250 μm, pitch 650
μm), and then an electron curtain conveyor type electron beam irradiation device (Electron EPZ- manufactured by ESI).
Type 2) in N ₂ atmosphere (O ₂ concentration 200 ppm)
Then, an electron beam was irradiated at an acceleration voltage of 160 kV and a dose of 6 Mrad to form an antibacterial cured film.

Similarly, the antibacterial curing composition was applied to the other surface and cured to obtain an antibacterial separate sheet having conductivity. Comparative Examples 2 to 3 20% by weight of talc, PAN having a diameter of 8 μm and a length of 6 mm
-Based carbon fiber (manufactured by Mitsubishi Rayon Co., Pyrofil TRO6
VBIE, trade name) 10% by weight containing propylene-ethylene block copolymer as a main component, thickness 1.5 mm,
A conductive separate sheet having a length of 1130 mm and a width of 1440 mm, and a conductive non-woven fabric obtained from carbon black-based conductive composite fibers on a molten resin film mainly composed of a propylene-ethylene block copolymer containing 20% by weight of talc. Were fused and integrated to prepare a conductive separate sheet having a thickness of 1.5 mm, a length of 1130 mm and a width of 1440 mm, and evaluated for antibacterial property.

The results of Examples 1 to 6 and Comparative Examples 1 to 3 are shown in Table 1 below.

[0034]

[Table 1]

From the results shown in Table 1, it can be seen that the antibacterial separate sheet of the present invention has extremely excellent antibacterial properties in both method A and method B. The example in which the present invention is applied to bulk packaging has been described above, but the present invention can be similarly applied as an antibacterial separate sheet for stacking or stacking articles such as containers other than bulk packaging.

[0036]

Since the antibacterial separate sheet of the present invention has antibacterial properties and durability, it does not become a hotbed of microorganisms and molds, exhibits excellent sanitary antibacterial performance, and has been developed so far. It can be used as a separate sheet for aseptic filling, which has been considered difficult.

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Claims (7)

[Claims] 1. An antibacterial separate sheet having an antibacterial cured film containing an antibacterial agent formed on one or both sides of a base sheet. 2. The antibacterial cured film is obtained by applying and curing an antibacterial curing composition containing an acrylate prepolymer, an acrylate reactive monomer and the antibacterial agent as essential components. Antibacterial separate sheet. 3. The content of the antibacterial agent in the antibacterial cured film is 0.
The antibacterial separate sheet according to claim 1, which is 1 to 5%. 4. The antibacterial separate sheet according to claim 1, wherein the antibacterial agent is inorganic solid particles retaining metal ions having a bactericidal action. 5. The antibacterial separate sheet according to claim 1, wherein the antibacterial cured film contains a conductive filler. 6. The antibacterial separate sheet according to claim 1, wherein the base sheet is a conductive thermoplastic resin sheet. 7. The separate sheet according to claim 1, wherein the cured film is an electron beam cured film.