JP2015074672A - Plastic sheet, protective sheet for display, and method for producing plastic sheet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a plastic sheet having excellent transparency, light resistance, surface hardness, rigidity, chemical / solvent resistance, heat resistance, heat and humidity resistance, antibacterial and / or antifungal properties, and excellent long-term durability. To provide.
SOLUTION: A plastic sheet obtained by curing a photocurable composition [I] containing an antibacterial agent and / or an antifungal agent, and within 1 μm in the thickness direction from one surface (α surface) of the plastic sheet. The content of the antibacterial active element and / or antifungal active element is higher than the content of the antibacterial active element and / or antifungal active element within 1 μm in the thickness direction from the other surface (β surface). Plastic sheet.
[Selection figure] None

Description

  The present invention relates to a plastic sheet imparted with antibacterial and / or antifungal properties, and in particular, a plastic sheet obtained by curing a photocurable composition, and more specifically, transparency, light resistance, surface hardness, The present invention relates to a plastic sheet that is excellent in rigidity and excellent in antibacterial and antifungal properties, and more particularly to a plastic sheet that is useful as a protective sheet for a display, and a method for producing the plastic sheet.

  2. Description of the Related Art Conventionally, a protective sheet made of glass, plastic, or the like is used on the front surface of a display in order to protect a display device such as a liquid crystal or PDP inside. In particular, a protective sheet on the forefront of a portable display device, an outdoor display device, or the like uses a plastic sheet such as polymethyl methacrylate or polycarbonate because mechanical strength such as impact resistance is required. These plastic sheets are required to have not only optical properties such as transparency and light resistance, but also mechanical properties such as surface hardness and rigidity, heat resistance, chemical resistance and solvent resistance. Therefore, the mainstream is a plastic sheet having a hard coat film formed on the surface, a multilayered or thick plastic sheet to ensure rigidity, and the like.

  In addition, the protective sheet here is a sheet on the outermost surface of the display, a sheet also serving as a detection function such as a touch panel, an outermost layer film of a card incorporating a display device, a cover sheet for waterproofing and antifouling Etc., and is used by being installed on the top of the display device or pasted on the display device.

  On the other hand, in recent years, the protective sheet is also required to be clean. In particular, there is a strong demand for a protective sheet that ensures cleanliness in a display that is touched or approached by an unspecified number of people. For example, displays at medical sites, schools, stations, banks, convenience stores, various public facilities, food factories, clothing factories, etc. have antibacterial and antifungal properties, as well as antiviral and antiallergenic functions. There is a need for a protective sheet having When a plastic sheet is used as the protective sheet, for example, when wrinkles occur, the wrinkles penetrate into the plastic sheet, optical properties such as transparency and hue of the plastic sheet, bending strength, bending elastic modulus, impact strength, Performances such as mechanical properties such as surface hardness are deteriorated, and the display performance of the display is deteriorated as a foreign matter, and further, malfunction of the display device is caused. Nutrient sources such as dust, dirt, food residue, sweat, and oil are easily attached to the protective sheet, which sometimes leads to explosive growth of the cocoon. Moreover, when moisture adheres to the surface of the protective sheet due to condensation or the like, bacteria are also likely to propagate.

  In order to solve these problems, a protective sheet in which a thermosetting resin layer having a surface hardness of 2H or more containing fine particles of an inorganic antibacterial agent is formed on a polyester film has been proposed (see, for example, Patent Document 1). ). Moreover, in order to maintain the cleanliness of the touch panel, an input device including an antibacterial-coated protective sheet has been proposed (see, for example, Patent Document 2). Further, a protection using a transparent resin molded body having a thickness of 0.1 to 5 mm, which is obtained by curing a photocurable composition [I] containing an antibacterial agent and / or an antifungal agent. Sheets have been proposed (see, for example, Patent Document 3).

JP 2006-299214 A JP-A-8-185560 JP 2011-38081 A

  However, even with these disclosed technologies, it is difficult to say that all the performances are satisfied. For example, the protective sheet disclosed in Patent Document 1 requires secondary processing such as coating, and surface hardness. Also, rigidity, chemical resistance and solvent resistance are insufficient. Moreover, since the protective sheet disclosed in Patent Document 2 requires a special transfer function, it must be expensive and is inferior in practicality. Furthermore, in the protective sheet disclosed in Patent Document 3, although antibacterial and antifungal effects can be obtained, the antibacterial agent and / or the antifungal agent is buried in the resin molded body, and the amount Since the effect cannot be obtained, in order to exhibit sufficient antibacterial and antifungal properties, it is necessary to add a considerable amount of antibacterial and antifungal agents such as 1% by weight, and such a considerable amount should be added. As a result, there is a possibility that not only economic efficiency but also various physical properties such as optical properties and mechanical properties may occur, and further improvements are demanded.

  In addition, as a method for imparting antibacterial and antifungal properties to a plastic sheet, a method of coating an antibacterial agent and an antifungal agent on a plastic sheet is also being studied, but in such a method, a process for coating is separately performed. Since it is necessary and the antibacterial and / or antifungal coating layer is laminated on the plastic sheet and separated, there is a possibility of problems such as peeling in a high temperature and high heat environment. It was not satisfactory.

  Therefore, in the present invention, in such a background, transparency, light resistance, surface hardness, rigidity, chemical / solvent resistance, heat resistance, heat and moisture resistance are excellent, and antibacterial and / or antifungal properties are further improved. The object is to provide a plastic sheet having excellent long-term sustainability.

  However, as a result of intensive studies by the present inventors to solve the above problems, a transparent plastic sheet obtained by curing the photocurable composition [I] containing an antibacterial agent and / or an antifungal agent, Focusing on the surface state of the plastic sheet, increasing the content of the antibacterial agent and / or antifungal agent on one surface (α surface) side, and antibacterial agent and / or antifungal agent on the other surface (β surface) side By lowering the content of the agent, it has excellent transparency, light resistance, surface hardness, rigidity, chemical / solvent resistance, heat resistance, moisture and heat resistance, as well as antibacterial and antifungal properties. The inventors have found that a plastic sheet having excellent antibacterial properties and antifungal properties and also excellent long-term sustainability can be obtained, and the present invention has been completed.

That is, the gist of the present invention is a plastic sheet obtained by curing a photocurable composition [I] containing an antibacterial agent and / or an antifungal agent, and has a thickness from one surface (α surface) of the plastic sheet. The content of antibacterial active element and / or antifungal active element within 1 μm in the direction is higher than the content of antibacterial active element and / or antifungal active element within 1 μm in the thickness direction from the other surface (β surface). It is related with the plastic sheet characterized by this.
Furthermore, the present invention also provides a protective sheet for display comprising the plastic sheet.

  Further, in the present invention, in producing a plastic sheet by curing the photocurable composition [I] containing an antibacterial agent and / or an antifungal agent, the two transparent plates facing each other with a predetermined gap are used. The molding space of the molding die is filled with the photocurable composition [I], and this is left to stand for 10 to 60 minutes in a horizontal state, and then irradiated with ultraviolet rays from at least one side through the molding die to be photocured. The manufacturing method of the plastic sheet characterized by hardening property composition [I] is also provided.

In the present invention, fungus means bacteria, and sputum means fungi.
In addition, the definition of antibacterial and antifungal properties in industrial products is not clear, and the level of requirements may vary depending on the application, but it shall conform to the guidelines of the Japan Household Appliances Fair Trade Council. That is, the antibacterial and antifungal properties in the present invention have a function of preventing the growth of microorganisms such as bacteria or spiders that have a direct or indirect adverse effect on the human body and adhere to the surface of the protective plate. I will say.

  The antibacterial and antifungal functions of the protective sheet are not temporary and must last for a certain period of time. For example, when an antibacterial component or the like is blended in the protective sheet, a sustained release property of the antibacterial component is required. It should be noted that functions such as antibacterial and antifungal properties do not need to be increased unnecessarily, and excessively high functions should be avoided in view of safety to the human body and environmental load.

  The plastic sheet of the present invention is excellent in transparency, light resistance, surface hardness, rigidity, chemical / solvent resistance, heat resistance, moisture and heat resistance, and antibacterial and / or antifungal properties, and also its long-term durability. In particular, it is a plastic sheet suitable for a protective sheet for a display.

Hereinafter, the present invention will be described in detail.
In the present invention, “(meth) acrylate” is a general term for acrylate and methacrylate.

  The plastic sheet of the present invention is obtained by curing a photocurable composition [I] containing an antibacterial agent and / or an antifungal agent.

  The plastic sheet of the present invention is plate-like, and its thickness directly affects the rigidity when used as a protective plate, and is preferably 0.1 to 5 mm. If the thickness is too thin, it tends to be deformed, it is difficult to maintain the shape of the protective plate, and it tends to be difficult to protect the display device. Conversely, if it is too thick, it tends to be difficult to reduce the weight and thickness of the display device. There is. A preferable range of the thickness is 0.2 to 4 mm, more preferably 0.3 to 3 mm, still more preferably 0.4 to 2 mm, and particularly preferably 0.5 to 1.5 mm.

  The present invention provides a plastic obtained by curing a photocurable composition [I] containing an antibacterial agent and / or an antifungal agent in order to impart an antibacterial and / or antifungal function to the plastic sheet. The content of the antibacterial active element and / or antifungal active element within 1 μm in the thickness direction from one surface (α surface) of the sheet, and the antibacterial active element within 1 μm in the thickness direction from the other surface (β surface) and / or Or it is characterized by being higher than content of an antifungal active element.

  In the present invention, the reason for using a plastic sheet obtained by curing the photocurable composition [I] is that it is easy to obtain characteristics such as surface hardness, rigidity, solvent resistance and chemical resistance as a protective plate, and antibacterial properties over a long period of time. This is because the antifungal property can be maintained. That is, the photocurable composition [I], which is usually liquid at about room temperature, easily dissolves or disperses the antibacterial agent and / or antifungal agent uniformly, and immediately after curing in the photocurable resin. The confined antibacterial agent and / or antifungal agent moves to the surface of the protective plate over time, and exhibits antibacterial and / or antifungal functions over a long period of time. On the other hand, in the plastic sheet, on the surface (β surface) which is lower than the content of the antibacterial active element and / or antifungal active element, the content is low. And various physical properties such as mechanical properties are not deteriorated. Furthermore, since the photocurable resin is generally insoluble in water, the antibacterial agent and / or antifungal agent is not wasted even when used as a protective plate under high humidity.

  As said photocurable composition [I], the composition containing an epoxy-type compound and a (meth) acrylate type compound is mention | raise | lifted, for example. Among these, a photocurable composition containing a polyfunctional (meth) acrylate compound and a photopolymerization initiator in addition to an antibacterial agent and / or an antifungal agent because a relatively thick plastic sheet can be produced with high productivity. Things are preferred.

  Many antibacterial agents and / or antifungal agents are unstable when heated for a long time, for example, deteriorate during high temperature melt molding of a thermoplastic resin, or yellow during thermosetting of a thermosetting composition. There is a tendency to do. By using the photocurable composition [I], the antibacterial agent and / or antifungal agent is incorporated without reducing the heating temperature and the heating time and without deteriorating the formulated antibacterial agent and / or antifungal agent. A plastic sheet can be obtained.

  Examples of the polyfunctional (meth) acrylate compound include polyfunctional (meth) acrylate compounds having two or more (meth) acryloyl groups in the molecule.

Examples of the bifunctional (meth) acrylate compound include ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, triethylene glycol di (meth) acrylate, tetraethylene glycol di (meth) acrylate, polyethylene glycol di ( (Meth) acrylate, propylene glycol di (meth) acrylate, dipropylene glycol di (meth) acrylate, polypropylene glycol di (meth) acrylate, butylene glycol di (meth) acrylate, neopentyl glycol di (meth) acrylate, 1,6- Hexanediol di (meth) acrylate, glycerin di (meth) acrylate, pentaerythritol di (meth) acrylate, ethylene glycol diglycidyl ether Di (meth) acrylate, diethylene glycol aliphatic di (meth) acrylate compounds such as diglycidyl ether di (meth) acrylate, bis (hydroxymethyl) tricyclo [5.2.1.0 ^{2, 6]} decane = di (meth ) Acrylate, bis (hydroxymethyl) tricyclo [5.2.1.0 ^2,6 ] decane = di (meth) acrylate, bis (hydroxy) pentacyclo [6.5.1.1 ^3,6 . 0 ^2,7 . 0 ^9,13 ] pentadecane = di (meth) acrylate, bis (hydroxymethyl) pentacyclo [6.5.1.1 ^3,6 . 0 ^2,7 . 0 ^9,13 ] pentadecane = di (meth) acrylate, 2,2-bis [4- (β- (meth) acryloyloxyethoxy) cyclohexyl] propane, 1,3-bis ((meth) acryloyloxymethyl) cyclohexane, 1,3-bis ((meth) acryloyloxyethyloxymethyl) cyclohexane, 1,4-bis ((meth) acryloyloxymethyl) cyclohexane, 1,4-bis ((meth) acryloyloxyethyloxymethyl) cyclohexane, etc. Alicyclic di (meth) acrylate compounds, 2,2-bis [4- (meth) acryloyloxyphenyl] propane, ethylene oxide modified bisphenol A type di (meth) acrylate, propylene oxide modified bisphenol A type di (meta ) Aromatic di (meta) such as acrylate ) Acrylate compounds and the like.

  Examples of the trifunctional or higher functional (meth) acrylate compound include trimethylolpropane tri (meth) acrylate, pentaerythritol tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, dipentaerythritol penta (meth) acrylate, and di Pentaerythritol hexa (meth) acrylate, tri (meth) acryloyloxyethoxytrimethylolpropane, glycerin polyglycidyl ether poly (meth) acrylate, ethylene oxide modified dipentaerythritol penta (meth) acrylate, ethylene oxide modified dipentaerythritol hexa (meth) ) Acrylate, ethylene oxide modified pentaerythritol tri (meth) acrylate, ethylene oxide modified pentaerythris Aliphatic polyfunctional (meth) acrylates such as alkylene oxide-modified poly (meth) acrylates such as tall tetra (meth) acrylate, 1,3,5-tris ((meth) acryloyloxymethyl) cyclohexane, 1,3, Modified with alicyclic polyfunctional (meth) acrylate such as 5-tris ((meth) acryloyloxyethyloxymethyl) cyclohexane, 1,3,5-tris ((meth) acryloyloxyethyl) benzene, isocyanuric acid ethylene oxide modified And aromatic (meth) acrylate compounds such as triacrylate.

  Furthermore, polyfunctional (meth) acrylate compounds such as epoxy (meth) acrylate, urethane (meth) acrylate, polyester (meth) acrylate, polyether (meth) acrylate, and the like can be given.

Among these, from the viewpoint of rigidity, bis (hydroxy) tricyclo [5.2.1.0 ^2,6 ] decane = di (meth) acrylate, bis (hydroxymethyl) tricyclo [5.2.1.0 ^{2 , 6} ] An alicyclic di (meth) acrylate having an alicyclic skeleton such as decane = di (meth) acrylate or an alicyclic polyfunctional urethane (meth) acrylate is preferable.

Moreover, the said polyfunctional (meth) acrylate type compound can also be used together 1 type, or 2 or more types.
Furthermore, you may use together the said polyfunctional (meth) acrylate type compound and a monofunctional (meth) acrylate type compound.

  Specific examples of the photopolymerization initiator include acetophenone-based initiators such as 1-phenyl-2-hydroxy-2-methylpropan-1-one, 1-hydroxycyclohexyl phenyl ketone, and 4-diphenoxydichloroacetophenone, benzophenone Benzophenone initiators such as methyl benzoylbenzoate, 4-phenylbenzophenone and hydro-benzobenzophenone, 2,6-dimethylbenzoyldiphenylphosphine oxide, 2,4,6-trimethylbenzoyldiphenylphosphine oxide, bis (2,4,6 -Phosphine oxide initiators such as trimethylbenzoyl) phenylphosphine oxide are used, and one or two of them are used in combination.

  These photopolymerization initiators are polyfunctional (meth) acrylate compounds (the total of polyfunctional (meth) acrylate compounds and monofunctional (meth) acrylate compounds when using monofunctional (meth) acrylate compounds) It is preferably used in a proportion of usually 0.1 to 10 parts by weight with respect to 100 parts by weight, more preferably 0.2 to 5 parts by weight, and particularly preferably 0.3 to 2 parts by weight. If the amount of the photopolymerization initiator is too small, curing tends to not proceed sufficiently, and if the amount is too large, the light transmittance of the resulting plastic sheet tends to decrease.

  As the antibacterial agent and antifungal agent used in the present invention, known antibacterial compounds and antifungal compounds can be used. In the present invention, known inorganic compounds and organic compounds may be mentioned. Among them, inorganic compounds are preferable from the viewpoint of molding processability, resistance to ultraviolet irradiation, heat treatment and the like. Specifically, for example, silver, copper , Metals such as zinc (including ions), metal oxides such as silver oxide, copper oxide, zinc oxide, magnesium oxide and titanium oxide, metal salts such as sodium percarbonate, sodium hypochlorite and silver phosphate, orthobora Boric acid compounds such as acid, metaboric acid, borax, thiosulfato silver salt, 2- (4-thiazolyl) benzimidazole silver salt, 2-pyridinethiol-1-oxide sodium salt, bis (2-pyridinethiol-1- Oxide) Zinc salts and other complex compounds and their inorganicization such as zeolite support, ceramic support, silica gel support, montmorillonite support Things like.

  Among the inorganic compounds, inorganic compounds having a refractive index of 1.50 to 1.54 are preferable, and particularly preferable refractive indexes are 1.51 to 1.54, and more preferably 1.51 to 1.53. If the refractive index is too small or too large, the optical properties tend to decrease.

  Among these, metal oxides are preferable from the viewpoint of optical compatibility with the photocurable composition [I]. That is, a metal oxide having a refractive index of 1.50 to 1.54, more preferably a metal oxide having a refractive index of 1.51 to 1.54, particularly preferably a refractive index of 1.51 to 1.53. It is a metal oxide having

  In the present invention, a small amount of an organic compound antibacterial agent and / or antifungal agent, and further a natural antibacterial agent may be used in combination with an inorganic compound antibacterial agent and / or antifungal agent.

  Examples of the organic compound antibacterial agent include 3- (trimethoxysilyl) propyldimethyloctadecylammonium chloride, tetradecyldimethylbenzylammonium chloride, 1-hexadecylpyridinium chloride, hexadecyltrimethylammonium bromide, hexadecyltrimethylammonium chloride, N-polyoxyethylene-N, N, N-trimethylammonium chloride, cetyltrimethylammonium chloride, octadecyltrimethylammonium chloride, didecyldimethylammonium chloride, benzalkonium chloride, behenyltrimethylammonium chloride, benzethonium chloride, 4,4'- (Tetramethylenedicarbonyldiamino) bis (1-decylpyridinium bromide), N, N′- Xamethylenebis (4-carbamoyl-1-decylpyridinium salt), 4,4 ′-(p-phthalamido) bis (1-octylpyridinium bromide), 3,3 ′-(m-phthalamido) bis (1-octylpyridinium) Quaternary ammonium salt compounds such as iodide), monohydric phenol compounds such as 5-chloro-2- (2,4-dichlorophenoxy) phenol, 2- (3,5-dimethylpyrazolyl) -4-hydroxy-6- Pyridine compounds such as phenylpyridine, alcohol compounds such as 2- (hydroxymethylamino) ethanol and 2- (hydroxymethylamino) -2-methylpropanol, phosphonium salts such as tetradecyltrimethylphosphonium chloride and didecyldimethylphosphonium chloride Compounds, chlorogluconate Chlorhexidine-based compounds, and the like.

Examples of antifungal agents for organic compounds include, for example, haloallylsulfone compounds such as 1-[(diiodomethyl) sulfonyl] -4-methylbenzene, and iodopropargyl compounds such as 3-iodo-2-propargylbutylcarbamate N-, such as N, N-dimethyl-N ′-(fluorodimethylthio) -N′-phenylsulfanide, N, N-dimethyl-N ′-(fluorodichloromethylthio) -N′-phenylsulfamide Haloalkylthio compounds, nitrile compounds such as 2,3,5,6-tetrachloroisophthalonitrile, 2,4,5,6-tetrachloroisophthalonitrile, 2,3,5,6-tetrachloro-4- ( Pyridine compounds such as methylsulfonyl) pyridine and benzoithiazole compounds such as 2- (thiocyanomethylthio) benzothiazole Isothiazoline compounds such as 2-n-octyl-4-isothiazolin-3-one, 2-methyl-4-isothiazolin-3-one, and 5-chloro-2-methyl-4-isothiazolin-3-one, p- Phenolic compounds such as chloro-m-cresol, alkylene bisphenol sodium, 2,4,4′-trichloro-2′-hydroxydiphenyl ether, o-phenylphenol, hexahydro-1,3,5-tri (2-hydroxyethyl)- Triazine-based compounds such as s-triazine, thiadiazine-based compounds such as 3,5-dimethyl-tetrahydro-1,3,5,2H-thiadiazine-2-thione, and anilide-based compounds such as 3,4,5-tribromosartylanilide Compound, 1- (3-chloroallyl) -3,5,7-triaza-1-azoniaadama Adamantane compounds such as tankrolide, dithiocarbite compounds such as tetramethylthiuram disulfide, bis (dimethylthiocarbamoyl) disulfide, bis (diethylthiocarbamoyl) disulfide, and brominated indanones such as 2,2-dibromo-1-indanone Compounds, benzoic acid compounds such as benzyl bromoacetate and p-hydroxybenzoic acid ester, sulfone compounds such as 3,4,5-tribromosalicylanilide, N- (trichloromethylthio) phthalimide, N-trichloromethylthio-4- Phthalimide compounds such as cyclohexene-1,2-dicarboximide, N-1,1,2,2-tetrachloroethylthiotetrahydrophthalimide, N- (fluorodichloromethylthio) phthalimide, 2- (4-thia Ril) benzimidazole, 2- (carbomethoxyamino) benzimidazole, benzimidazolecarbamic acid methyl ester, imidazole compounds such as 2-benzimidazole methylcarbamate, halodiallylurea compounds such as triclocarban, polyhexamethylenepiguanidine hydrochloride, Guanidine compounds such as chlorohexidine hydrochloride, fatty acid ester compounds such as propylene glycol monofatty acid ester and glycerin fatty acid ester, amide compounds such as 2,2-dibromo-2-cyanopropionamide, iodo such as diiodomethyl-p-tolylsulfone Compounds, N- (1,1,2,2-tetrachloroethylthio) -4-cyclohexene-1,2-dicarboximide, N- (trichloromethylthio) -4-cyclohex Carboxyimide compounds such as down-1,2-dicarboximide, benzoquinone-based compounds such as 2,6-dimethoxy -p- benzoquinone, paraben compounds such methylparaben and ethylparaben, and the like.

  Examples of the natural antibacterial agent include natural compounds such as chitosan, 孟 mul bamboo extract, Japanese mustard extract, wasabi extract, hiba extract, oyster shell, protamine, and polylysine.

  Here, examples of the bacteria in the present invention include Staphylococcus aureus, MRSA (methicillin-resistant Staphylococcus aureus), Escherichia coli, Pseudomonas aeruginosa, Micrococcus sp., Pediococcus sp., Proteus vulgaris, Pseudomonas aeruginosa, Pseudomonas putida, Pesudomonas putida, Pseudomonas alcaligenes, Pseudomonas Pseudoalcaligenes, Pseudomonas cepacia, Alcaligenes defnitrificans, Alcaligenes faecalis, Bacillus subtils, Bacillus cerens, Acinetobacter calcoaceticus, Alcaligenes faecalis, Peptococcus sp., Neisseria sp., Salmonella typhimurium, Vibrio parahaemolyticus, Enterobacter cloacea, Citrobacter freundii, Kiebsiella pneumoniae, Examples include Actinomyces and Thiobacillus genus bacteria.

  Examples of the cocoons in the present invention include Candida albicnas, Aspergillus niger, Aspergillus terrus, Penicillium citrinum, Aspergillus penicilloides, Penicillium funiculosum, Penicillium digitatum, Aureobasidium pullulans, Phomasporium cladosporioides, Cladospium, sperdospium, Aspergillus fumigatus, Aspergillus terreus, Geotrichum sp., Alternaria sp., Alternaria Alternata, Fusarium solani, Nigrospora Oryzae, Pestalotia adusta, Trichoderma T-1, Trichoderma sp., Trichoderma harzianu, Chaetomium pus And fungi belonging to the genus Curvularia, Eurochiumu, Nocardia, Streptomyces, Deccrosphaera, Cochliobolus, Acremonium and the like.

There are many antibacterial compounds having antifungal properties, and many antifungal agents have antibacterial properties. In the present invention, the two are described separately for convenience, but it should be noted that it is difficult to strictly separate them.
In addition, antibacterial and antifungal properties often exhibit deodorant and antiseptic properties as a result, and can be added as an effect of the present invention.
In addition, antibacterial agents and antifungal agents are sometimes referred to as day keeping improvers and preservatives.

  The photocurable composition [I] may further contain an antiviral agent or an antiallergen agent.

Examples of the antiviral agent include thiosulfato silver salt, hydroxytyrosol, glutaral, hexachlorophene, chlorohexidine and the like.
In addition, as a virus in this invention, normally, filmless viruses, such as film viruses, such as an AIDS virus, a measles virus, a herpes simplex virus, an influenza virus, and a poliovirus, etc. are mention | raise | lifted.

Examples of the anti-allergen include polyphenol compounds such as polyphenol, polycresol, polymethoxyphenol, polyvinylphenol compounds, polybisphenol A compounds, lignophenol compounds, tannic acid, polytyrosine, and the like.
The allergen in the present invention is not particularly limited as long as it causes allergic diseases such as atopic dermatitis, bronchial asthma, and allergic rhinitis, and is generated from mite allergen, cedar pollen allergen, and these allergens. Examples include allergenic substances.

  It is preferable that content of an antibacterial agent and / or an antifungal agent is 0.0005 to 0.5 weight% with respect to photocurable composition [I]. More preferably, it is 0.001-0.4 weight%, Most preferably, it is 0.003-0.3 weight%. If the content of the antibacterial agent and / or antifungal agent is too small, the antibacterial and / or antifungal function of the plastic sheet tends to be insufficient. Conversely, if the content is too large, the optical properties and mechanical properties are affected. In addition, there is a tendency to be concerned about adverse effects on the environment and the human body.

  Moreover, the photocurable composition [I] used in the present invention may appropriately contain an auxiliary component such as a surfactant for the purpose of uniform dispersion of the antibacterial agent and / or antifungal agent.

  Furthermore, the photocurable composition [I] used in the present invention may contain a small amount of auxiliary components as long as the object of the present invention is not impaired. For example, thermoplastic resins, polymerization inhibitors, thermal polymerization initiators, chain transfer agents, antioxidants, yellowing inhibitors, ultraviolet absorbers, bluing agents, dyes and pigments, antifoaming agents, leveling agents, thixotropic agents , Flame retardants, thickeners, various fillers and the like.

  The photocurable composition [I] thus obtained is used to obtain the plastic sheet of the present invention. In the present invention, the antibacterial active element and / or the antibacterial element on one surface (α surface) of the plastic sheet is obtained. It is important that the content of the soot active element is higher than the content of the antibacterial active element and / or the antifungal active element on the other surface (β plane).

In the present invention, the antibacterial active element and / or antifungal active element content on the α-plane side of the plastic sheet is 1.0 × 10 ^{17 to} 1.0 × 10 ²⁰ atms in terms of antibacterial and / or antifungal properties. / Cc, preferably 1.0 × 10 ^{17 to} 1.0 × 10 ¹⁹ atms / cc, more preferably 1.0 × 10 ^{17 to} 7.0 × 10 ¹⁸ atms / cc. . If the content is too small, the antibacterial and / or antifungal properties may be lowered, and if it is too large, the optical properties may be lowered, particularly the optical properties after time may be lowered.

In the present invention, the content of the antibacterial active element and / or the antifungal active element on the β-plane side of the plastic sheet is less than 1.0 × 10 ¹⁷ atoms / cc, particularly 1.0 × 10 ¹⁵ atoms / cc. The following is preferable from the viewpoint of optical properties. If the content is too large, unnecessary bleed-out occurs, and the optical properties tend to decrease.

Here, in the present invention, the content of the antibacterial active element and / or antifungal active element on the α-plane side of the plastic sheet is, for example, a value measured using secondary ion mass spectrometry (SIMS). That is.
In addition, the content of the antibacterial active element and / or antifungal active element on the β-plane side of the plastic sheet is measured by, for example, a method using secondary ion mass spectrometry (SIMS) or Stokes representing the sedimentation rate of particles. The method of calculating using the formula is used.

The plastic sheet of the present invention is, for example, a method in which a molded plastic sheet is immersed in a liquid containing an antibacterial agent and / or an antifungal agent, and an antibacterial active element and / or a plastic sheet after molding in a supercritical fluid. Examples thereof include a method for introducing an antifungal active element and a method for introducing an antibacterial active element and / or an antifungal active element into a plastic sheet after molding by an ion implantation method. In particular, a predetermined gap is provided. The molding space consisting of two opposing transparent plates is filled with the photocurable composition [I] and allowed to stand in a horizontal state for 10 to 60 minutes, and then passed through the molding die. It is preferable to produce the composition by curing the photocurable composition [I] by irradiation with light, particularly ultraviolet irradiation. A preferable range of the time for standing in a horizontal state is 10 to 30 minutes, and more preferably 10 to 20 minutes. If the horizontal state time is too short, antibacterial and / or antifungal properties tend to be difficult to obtain, and if it is too long, there is a tendency for optical properties to deteriorate, particularly optical properties after time.

  Further, in order to make the content of the antibacterial active element and / or antifungal active element on the α plane side of the plastic sheet higher than the content of the antibacterial active element and / or antifungal active element on the β plane side, light irradiation is performed. Is more preferably performed from the β-plane side of the plastic sheet.

Light irradiation may be performed in several stages. In order to accelerate and complete the curing, it is also preferable to heat the plastic sheet at the time of light irradiation or after irradiation.

  The material of the mold is not particularly limited as long as at least one of the molds transmits light, and glass, metal, or resin can be used. Among these, a glass or transparent resin mold is preferable in terms of light translucency. When an opaque mold is used, a mold made of a transparent material is used for the mold on the opposite surface, and light is irradiated from the opposite surface side.

As light to be used, light such as far ultraviolet light, ultraviolet light, near ultraviolet light, and infrared light can be used. However, curing by ultraviolet irradiation is advantageous from the viewpoint of curing speed, availability of an irradiation device, price, and the like. As a light source in ultraviolet irradiation, a chemical lamp, a xenon lamp, a low-pressure mercury lamp, a high-pressure mercury lamp, a metal halide lamp, or the like is usually used. Irradiation energy is usually about 0.1 to 10 J / cm ² . Excessive irradiation tends to cause inactivation of the antibacterial agent and / or antifungal agent.

  It is also possible to form fine unevenness on the surface of the plastic sheet to provide antiglare and water repellent functions and fine unevenness (called anti-Newton ring function) to avoid interference fringes. is there. In particular, imparting a water-repellent function with fine irregularities is also preferable from the viewpoint of reducing the adhesion of bacteria and sputum. In these cases, a mold having a fine uneven shape on the surface thereof is used for at least one of the molds, and it is possible to form the fine unevenness on the surface of the plastic sheet itself.

  The plastic sheet of the present invention preferably has a light transmittance of 80% or more from the viewpoint of transparency when used as a protective plate. The light transmittance of the plastic sheet is more preferably 85% or more, and particularly preferably 90% or more. In general, the upper limit of the light transmittance is 99%.

  As a method for improving the light transmittance, a method for specifying the component and content of the photocurable composition [I] (for example, using a monomer that does not contain an aromatic ring as a polyfunctional (meth) acrylate, or starting photopolymerization) Adjusting the amount of the agent, etc.), a method for identifying the components and contents of the antibacterial agent and / or antifungal agent, a method for adding an antioxidant as an auxiliary component, a method for controlling the curing conditions ( For example, the amount of light should not be increased excessively, or irradiation with inert gas may be performed.

  Furthermore, the plastic sheet of the present invention preferably has a pencil hardness of 2H or more from the viewpoint of surface hardness when used as a protective plate, more preferably 3H or more, and particularly preferably 4H or more. In adjusting the pencil hardness to the above range, a method of appropriately controlling the kind of the above-described photocurable composition [I] and the blending amount of the components can be used. For example, as a polyfunctional (meth) acrylate, a method using a polyfunctional urethane (meth) acrylate compound or a trifunctional or higher functional compound can be used. In general, the upper limit of the pencil hardness of the plastic sheet is 8H.

The plastic sheet of the present invention preferably has a flexural modulus of 3 GPa or more from the viewpoint of rigidity when used as a protective plate, more preferably 3.5 GPa or more, and particularly preferably 4 GPa or more. In adjusting the bending elastic modulus to the above range, a method of appropriately controlling the kind of the above-described photocurable composition [I] and the blending amount of the components can be mentioned. In addition, the upper limit of the bending elastic modulus of a plastic sheet is 10 GPa.

  The plastic sheet of the present invention thus obtained is excellent in transparency and mechanical strength, and has excellent antibacterial and antifungal properties, and also its long-term durability, and is very useful as a protective plate for various displays. It is.

EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples. However, the present invention is not limited to the following examples unless it exceeds the gist.
In the examples, “parts” and “%” mean weight basis.
Each evaluation was performed as follows.

(1) Content of antibacterial active element and / or antifungal active element contained within 1 μm in thickness direction from one surface (α surface) of plastic sheet (α1)
The amount (atoms / cc) of the content (α1) was measured by the sensitivity in the Si substrate by secondary ion mass spectrometry (SIMS).

(2) Content of antibacterial and / or antifungal active elements contained within 1 μm in the thickness direction from one surface (β surface) of the plastic sheet (β1)
It was calculated using the Stokes equation representing the sedimentation rate of the particles.

(3) Light transmittance The total light transmittance (%) of the plastic sheet was measured using a Nippon Denshoku haze meter “NDH-2000”.

(4) Pencil hardness The pencil hardness of the plastic sheet was measured according to JIS K 5600-5-4.

(5) Water absorption The plastic sheet was immersed in ultrapure water at 23 ° C. for 20 days, and the weight increase was measured.
○ ・ ・ ・ 1.5% or less × ・ ・ ・ greater than 1.5%

(6) Antibacterial properties The α-side of the plastic sheet after 20 days from the production was tested in accordance with JIS Z 2801, and Staphylococcus aureus (E. aureus) and Escherichia coli (E. coli) were evaluated as follows. . In addition, as a non-processed film used as a reference, the film of Comparative Example 1 containing no antibacterial agent and / or antifungal agent was used.
○: Antibacterial activity value of 2 or more for any fungus Δ: Antibacterial activity value of 2 or more for any fungus × Less than antibacterial activity value of 2 for any fungus

(7) Heat resistance The b value after heating the plastic sheet at 150 ° C. for 3 hours was measured and evaluated according to the following criteria.
○ ... b value is less than 0.5 × ... b value is 0.5 or more

(8) Humidity and heat resistance The haze after the plastic sheet was left in an atmosphere of 60 ° C. and 90% RH for 500 hours was measured and evaluated according to the following criteria.
○ ・ ・ ・ Haze is less than 1% × ・ ・ ・ Haze is 1% or more

<Example 1>
Bis (hydroxymethyl) tricyclo [5.2.1.0 ^2,6 ] decane = diacrylate (manufactured by Shin-Nakamura Chemical Co., Ltd., “A-DCP”), phosphate, which is a silver-based inorganic compound as an antibacterial agent 0.005 part of glass (refractive index 1.526), 1 part of 1-hydroxycyclohexyl phenyl ketone (manufactured by Ciba Geigy Co., Ltd., “Irgacure 184”) as a photopolymerization initiator is stirred until uniform at 60 ° C., A photocurable composition [I] was obtained. This photocurable composition [I] was poured into a molding die composed of two opposed glass plates using a 0.7 mm thick silicon plate as a spacer (23 ° C.), and left still for 15 minutes in a horizontal state. I put it. Then, using a metal halide lamp, ultraviolet rays were irradiated from above with an illuminance of 100 mW / cm ² and a light amount of 5 J / cm ² , and then demolded to obtain a plastic sheet having a width of 30 cm × length of 30 cm × thickness of 0.7 mm. It was.
The evaluation results of the obtained plastic sheet are as shown in Table 2, and had good performance as a protective plate.

<Example 2>
In Example 1, after injecting the photocurable composition [I] into a mold, it was left in a horizontal state for 10 minutes in the same manner, and the width was 30 cm, the length was 30 cm, and the thickness was 0.7 mm. A plastic sheet was obtained.
The evaluation results of the obtained plastic sheet are as shown in Table 2, and had good performance as a protective plate.

<Comparative Example 1>
In Example 1, a plastic sheet having a width of 30 cm, a length of 30 cm and a thickness of 0.7 mm was obtained in the same manner except that no antibacterial agent was added.
The evaluation result of the obtained plastic sheet is as shown in Table 2. Although it has good performance as a protective plate, it did not have antibacterial properties.

<Comparative Example 2>
In Example 1, after injecting the photocurable composition [I] into the mold, and immediately irradiating without leaving the standing time, the width 30 cm × length 30 cm × thickness 0.7 mm A plastic sheet was obtained.
The evaluation result of the obtained plastic sheet is as shown in Table 2. Although it has good performance as a protective plate, it did not have good antibacterial properties.

<Comparative Example 3>
In Example 1, 0.2 part of phosphate glass (refractive index: 1.526), which is a silver-based inorganic compound, was added as an antibacterial agent, and the photocurable composition [I] was injected into the mold and then allowed to stand. A plastic sheet having a width of 30 cm, a length of 30 cm and a thickness of 0.7 mm was obtained in the same manner except that the irradiation was performed immediately without taking time.
The evaluation result of the obtained plastic sheet is as shown in Table 2. Although it has antibacterial properties, it did not have good performance as a protective plate.

  As can be seen from the above evaluation results, the photocurable composition is cured by adding an antibacterial agent and / or antifungal agent, and one surface is more antibacterial active element and / or antifungal than the other surface. The plastic sheet of the example having a high content of the active element is excellent in transparency, surface hardness, rigidity, solvent resistance, heat resistance, heat and moisture resistance, and has a very small amount of antibacterial agent and / or antifungal agent. In spite of this, it has excellent antibacterial and / or antifungal properties on the side where antibacterial and / or antifungal agents are required, and is particularly suitable as a plastic sheet suitable for a protective sheet for displays. I know that there is. On the other hand, the plastic sheet of the comparative example did not satisfy all, and was not satisfied as a protective sheet excellent in antibacterial and / or antifungal properties.

  The plastic sheet of the present invention can be advantageously used for various optical materials and electronic materials. For example, liquid crystal substrates, organic / inorganic EL substrates, PDP substrates, electronic paper substrates, light guide plates, retardation plates, touch panels, optical filters, etc., various display members, storage / recording applications including optical disk substrates, It can be used for energy applications such as thin-film battery substrates and solar cell substrates, optical communication applications such as optical waveguides, functional films and sheets, and various optical films and sheets. In addition to optical materials and electronic materials, it can also be used for, for example, automotive materials, building materials, medical materials, stationery, and the like.

Claims (12)

  A plastic sheet obtained by curing a photocurable composition [I] containing an antibacterial agent and / or an antifungal agent, and having an antibacterial active element within 1 μm in the thickness direction from one surface (α surface) of the plastic sheet And / or a plastic sheet, wherein the content of the antifungal active element is higher than the content of the antibacterial active element and / or the antifungal active element within 1 μm in the thickness direction from the other surface (β surface). The content of the antibacterial active element and / or the antifungal active element within 1 μm in the thickness direction from the other surface (β surface) of the plastic sheet is less than 1 × 10 ¹⁷ atoms / cc. Plastic sheet.   The plastic sheet according to claim 1 or 2, wherein the thickness is 0.1 to 5 mm.   The plastic sheet according to any one of claims 1 to 3, wherein the photocurable composition [I] contains a polyfunctional (meth) acrylate compound and a photopolymerization initiator.   5. The plastic according to claim 1, wherein the content of the antibacterial agent and / or the antifungal agent is 0.0005 to 0.5 wt% with respect to the photocurable composition [I]. Sheet.   The plastic sheet according to any one of claims 1 to 5, wherein the antibacterial agent and / or the antifungal agent is an inorganic compound.   The plastic sheet according to any one of claims 1 to 6, wherein the antibacterial agent and / or the antifungal agent is an inorganic compound having a refractive index of 1.50 to 1.54.   The plastic sheet according to any one of claims 1 to 7, wherein the light transmittance is 80% or more.   9. The plastic sheet according to claim 1, wherein the pencil hardness is 2H or more and the flexural modulus is 3 GPa or more.   The plastic sheet according to claim 1, wherein the plastic sheet is used as a protective sheet for a display.   A protective sheet for a display comprising the plastic sheet according to claim 1. In producing a plastic sheet by curing a photocurable composition [I] containing an antibacterial agent and / or an antifungal agent, a molding space formed of two transparent plates facing each other with a predetermined gap therebetween Is filled with the photocurable composition [I], and allowed to stand for 10 to 60 minutes in a horizontal state, and then irradiated with ultraviolet rays from at least one side through a mold, so that the photocurable composition [I] A method for producing a plastic sheet, characterized by curing the material.