JP2011052157A - Acrylic resin composition and fluorescent yellowish green film of the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an acrylic resin composition that can give a fluorescent film having high transparency and excellent in fading resistance. <P>SOLUTION: The acrylic resin composition contains a (meth)acrylic resin, a polycarbonate whose melt mass flow rate under load of 1.2 kgf at a temperature of 300°C is ≥15 g/10 min and ≤100 g/10 min, and a thioxanthene compound. The fluorescent yellowish green film is made by molding the acrylic resin composition. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an acrylic resin composition and a fluorescent yellow-green film thereof.

  Polycarbonate has high transparency and is excellent in impact resistance and heat resistance. Furthermore, when a dye or a pigment is added, it is colored with high transparency. In particular, when a fluorescent dye is used, vivid fluorescent color is generated and the sustainability of fluorescent coloring is high. Therefore, conventionally, it has been used for the transparent film colored in the fluorescence of the fluorescent retroreflection sheet material.

  However, the weather resistance of the polycarbonate itself is poor, and the resin tends to deteriorate and yellow. Therefore, it has been practiced to improve the fluorescence persistence of the polycarbonate resin by adding a hindered amine light stabilizer or an ultraviolet absorber to the polycarbonate resin using the fluorescent colorant (for example, Patent Document 1).

  Also, from the viewpoint of outstanding transparency, weather resistance, and low birefringence of acrylic resin, dye resin fading resistance and polycarbonate resin's resistance can be improved by pasting acrylic resin containing UV absorbers to the polycarbonate resin layer surface. A technique for suppressing deterioration (for example, Patent Document 2) has been developed.

  As described above, it has been attempted to apply an acrylic resin to a fluorescent transparent film of a fluorescent retroreflective sheet material because it has excellent transparency and weather resistance enough to be applied to the surface layer. When a dye or a pigment is added to the acrylic resin, the acrylic resin is colored with high transparency, so that a colorful color tone can be achieved. Even when a fluorescent dye is used, it produces a vivid fluorescent color. However, in the environment exposed to the sun, the dye will fade quickly.

Japanese Patent No. 3447744 Patent 3002042

  The present invention provides an acrylic resin composition that can provide a fluorescent film having high transparency and excellent fade resistance.

  As a result of intensive studies by the present inventors in order to solve the above-mentioned problems, when a specific dye and a specific polycarbonate resin are added to an acrylic resin, the resulting film maintains high transparency while maintaining an acrylic film. Then, it discovered that it had the outstanding fade resistance which was difficult until now, and came to complete this invention.

That is, the present invention
[1] An acrylic resin composition comprising a (meth) acrylic resin, a polycarbonate having a melt mass flow rate of 15 g / 10 min to 100 g / 10 min at a temperature of 300 ° C. and a load of 1.2 kgf, and a thioxanthene compound,
[2] 50 to 99.9% by weight of acrylic acid ester, 0 to 49.9% by weight of other vinyl monomers copolymerizable and 2 per copolymerizable molecule of (meth) acrylic resin At least one acrylate ester-based crosslinked elastomer 5 obtained by polymerizing the monomer mixture (a-1) composed of 0.1 to 10% by weight of the polyfunctional monomer having the above non-conjugated double bond. In the presence of 85 parts by weight, 95 to 15 parts by weight of a monomer mixture (a-2) consisting of 50 to 100% by weight of a methacrylic acid ester and 0 to 50% by weight of another copolymerizable vinyl monomer [The total amount of (a-1) and (a-2) is 100 parts by weight] The acrylic resin composition according to [1], comprising acrylic rubber particles obtained by copolymerization,
[3] The acrylic resin composition according to [1] or [2], wherein the polycarbonate is 10 parts by weight or less with respect to 100 parts by weight of the (meth) acrylic resin,
[4] A methacrylic resin obtained by copolymerizing a monomer mixture comprising 80 to 100% by weight of a methacrylic acid ester and 0 to 20% by weight of another copolymerizable vinyl monomer. The acrylic resin composition according to any one of [1] to [3], comprising a polymer (b);
[5] The acrylic resin composition according to any one of [1] to [4], further comprising a benzotriazole-based compound and / or a triazine-based compound as an ultraviolet absorber.
[6] The acrylic resin composition according to any one of [1] to [5], further comprising a hindered amine light stabilizer,
[7] The acrylic resin composition according to [5] or [6], wherein the content of the ultraviolet absorber is 0.5 to 5 parts by weight with respect to 100 parts by weight of the (meth) acrylic resin,
[8] The acrylic resin composition according to [6] or [7], wherein the content of the hindered amine light stabilizer is 0.5 to 5 parts by weight with respect to 100 parts by weight of the (meth) acrylic resin,
[9] A fluorescent yellow-green film formed by molding the acrylic resin composition according to any one of [1] to [8],
[10] The fluorescent yellow-green film according to [9], wherein the film thickness is 30 to 300 μm,
[11] When measured using the 0/45 arrangement and evaluated by CIE standard light D65, (0.479, 0.520), (0.446, 0.483), ( 0.512, 0.421) and chromaticity coordinates (x, y) within the region defined by (0.557, 0.442) and remain within this standard even after 250 hours of accelerated testing. The fluorescent yellow-green film according to [9] or [10].
[12] The fluorescent yellow-green film according to any one of [9] to [11], which is for a retroreflective sheet,
It is.

  According to the acrylic resin composition of the present invention, it is possible to obtain a film that has long-time fluorescence retention and fading resistance and also has transparency.

  A well-known thing can be used for the (meth) acrylic resin used for the acrylic resin composition of this invention.

  From the viewpoint of impact resistance of the film, the (meth) acrylic resin preferably contains acrylic rubber particles. Bending crack resistance and workability can be imparted to a film obtained by processing.

  Although it does not specifically limit in (meth) acrylic-type resin, Acrylic acid ester, the other vinyl-type monomer which can be copolymerized as needed, and two or more nonconjugated doubles per copolymerizable molecule | numerator In the presence of at least one acrylic ester-based crosslinked elastomer obtained by polymerizing a monomer mixture (a-1) comprising a polyfunctional monomer having a bond, a methacrylate ester and other copolymerizable monomers Contains acrylic rubber particles [total amount of (a-1) and (a-2) is 100 parts by weight] obtained by copolymerizing a monomer mixture (a-2) comprising a vinyl monomer. It is preferable. A film excellent in impact resistance can be obtained with high transparency.

  As the acrylic rubber particles, a monomer mixture comprising 50 to 100% by weight of a methacrylic acid ester and 0 to 50% by weight of another copolymerizable vinyl monomer in the presence of an acrylic ester-based crosslinked elastic body. What is obtained by copolymerizing (a-2) is preferred.

  The acrylic ester-based cross-linked elastic body is a cross-linked elastic body mainly composed of an acrylic ester. More specifically, a polyfunctional monomer having two or more non-conjugated double bonds per molecule that can be copolymerized with an acrylic ester, other vinyl monomers that can be copolymerized as required. A polymer obtained by polymerizing a monomer mixture (a-1) consisting of a monomer (hereinafter sometimes simply referred to as “polyfunctional monomer”) can be preferably used. The monomer mixture (a-1) may be completely mixed (one-stage polymerization) for polymerization, or the composition of the monomer mixture (a-1) may be changed twice or more (two-stage polymerization or more). ) And may be polymerized separately.

  The acrylic ester in the acrylic ester-based crosslinked elastic body is preferably an alkyl alkyl acrylate, and more preferably an alkyl group having 1 to 12 carbon atoms from the viewpoint of polymerizability and cost. Specific examples thereof include methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate, 2-ethylhexyl acrylate, and n-octyl acrylate. These may be used alone or in combination of two or more.

  The amount of acrylate ester in the acrylate ester-based crosslinked elastic body is preferably 50 to 99.9% by weight, more preferably 70 to 99.9% by weight in 100% by weight of the monomer mixture (a-1), and 80 to 99.9% by weight is most preferred. When the amount of the acrylate ester is less than 50% by weight, the impact resistance is lowered, the elongation at the time of tensile break is lowered, and cracks tend to be generated at the time of film cutting.

  Examples of other copolymerizable vinyl monomers in the acrylic ester-based crosslinked elastomer include, for example, methyl methacrylate, ethyl methacrylate, propyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, t-methacrylic acid t- Methacrylic acid esters such as butyl, vinyl halides such as vinyl chloride and vinyl bromide, vinyl cyanides such as acrylonitrile and methacrylonitrile, vinyl esters such as vinyl formate, vinyl acetate and vinyl propionate, styrene, vinyl toluene, α -Aromatic vinyl derivatives such as methylstyrene, vinylidene halides such as vinylidene chloride and vinylidene fluoride, acrylic acids such as acrylic acid, sodium acrylate, calcium acrylate and salts thereof, β-hydroxyethyl acrylate, dimethyl acrylate amino Acrylic acid alkyl ester derivatives such as ethyl, glycidyl acrylate, acrylamide, N-methylol acrylamide, methacrylic acid and salts thereof such as methacrylic acid, sodium methacrylate, calcium methacrylate, methacrylamide, β-hydroxyethyl methacrylate, And alkyl methacrylate derivatives such as dimethylaminoethyl methacrylate and glycidyl methacrylate. These may be used alone or in combination of two or more. Among these, methacrylic acid esters are preferable from the viewpoint of weather resistance and transparency. More preferably, it is a methacrylic acid alkyl ester, and more preferably an alkyl group having 1 to 12 carbon atoms. The methacrylic acid ester may be linear or branched.

  The amount of the other copolymerizable vinyl monomer in the acrylic ester-based crosslinked elastic body is preferably 0 to 49.9% by weight and preferably 0 to 30% by weight in 100% by weight of the monomer mixture (a-1). % Is more preferable, and 0 to 20% by weight is most preferable. When the amount of the other vinyl monomer exceeds 49.9% by weight, impact resistance is lowered, elongation at the time of tensile break is lowered, and cracks are likely to be generated at the time of film cutting.

  The polyfunctional monomer having two or more non-conjugated double bonds per molecule that can be copolymerized in the acrylic ester-based crosslinked elastomer may be a commonly used monomer such as allyl methacrylate or allyl acrylate. , Triallyl cyanurate, triallyl isocyanurate, diallyl phthalate, diallyl malate, divinyl adipate, divinylbenzene, ethylene glycol dimethacrylate, diethylene glycol methacrylate, triethylene glycol dimethacrylate, trimethylolpropane trimethacrylate, tetromethylolmethane tetramethacrylate, Dipropylene glycol dimethacrylate and acrylates thereof can be used. These polyfunctional monomers may be used alone or in combination of two or more.

  The amount of the polyfunctional monomer having two or more non-conjugated double bonds per molecule that can be copolymerized in the acrylate cross-linked elastomer is determined by the stress along with the average particle size of the acrylate cross-linked elastomer. It greatly affects whitening, elongation at the time of tensile break, or transparency.

  The compounding amount of the polyfunctional monomer in the acrylic ester-based crosslinked elastic body is preferably 0.1 to 10% by weight, and 1.0 to 4% by weight in 100% by weight of the monomer mixture (a-1). More preferred. If the blending amount of the polyfunctional monomer is 0.1 to 10% by weight, it is preferable from the viewpoint of bending cracking resistance and resin fluidity during molding.

  Acrylic rubber particles are a monomer mixture comprising 50 to 100% by weight of a methacrylic acid ester and 0 to 50% by weight of another copolymerizable vinyl monomer in the presence of an acrylate-based crosslinked elastomer. Those obtained by copolymerizing a-2) are preferred. More preferably, in the presence of 5 to 85 parts by weight of an acrylic ester-based crosslinked elastomer, a monomer comprising 50 to 100% by weight of an alkyl methacrylate and 0 to 50% by weight of another copolymerizable vinyl monomer. It is obtained by copolymerizing 95 to 15 parts by weight of the monomer mixture (a-2) in at least one stage. However, the total amount of the acrylic ester-based crosslinked elastic body (monomer mixture (a-1)) and monomer mixture (a-2) shall satisfy 100 parts by weight.

  The blending amount of the methacrylic acid ester in the monomer mixture (a-2) is preferably 80% by weight or more, more preferably 85% by weight, and still more preferably 90% by weight in terms of hardness and rigidity.

  As other copolymerizable vinyl monomers, those used in the above-mentioned acrylic ester-based crosslinked elastic bodies and alkyl alkyl esters having 1 to 12 carbon atoms in the alkyl group can be used. Specific examples include methyl acrylate, ethyl acrylate, propyl acrylate, n-butyl acrylate, isobutyl acrylate, t-butyl acrylate, 2-ethylhexyl acrylate, n-octyl acrylate, and the like. These monomers may be used independently and may use 2 or more types together.

  At this time, in the monomer mixture (a-2) (graft copolymerization composition), a component (free polymer) that becomes an ungrafted polymer is generated without grafting to the acrylate-based crosslinked elastic body. This component (free polymer) can be used as a component of a (meth) acrylic resin.

  A part of the acrylic rubber particles [acrylic ester-based crosslinked elastic body and grafted (a-2)] becomes insoluble in methyl ethyl ketone.

  The graft ratio to the acrylic ester-based crosslinked elastic body is preferably 30 to 250%, more preferably 50 to 230%, and still more preferably 70 to 220%. If the graft ratio is less than 30%, the transparency tends to decrease, or the elongation at the time of tensile breakage tends to decrease, and cracks tend to occur during film cutting. If it exceeds 250%, the melt viscosity at the time of film formation tends to be high, and the moldability of the film tends to deteriorate.

  The production method of the acrylic rubber particles is not particularly limited, and a known emulsion polymerization method, emulsion-suspension polymerization method, suspension polymerization method, bulk polymerization method or solution polymerization method can be applied. Particularly preferred.

  The average particle diameter of the acrylic rubber particles is preferably more than 100 nm and not more than 400 nm, more preferably more than 100 nm and not more than 350 nm, and still more preferably more than 100 nm and not more than 300 nm. When the average particle diameter of the acrylic rubber particles is 100 nm or less, the impact resistance and bending cracking resistance of the film tend to decrease. If it exceeds 400 nm, the transparency of the film tends to decrease. The average particle diameter of the acrylic rubber particles here is a value measured by using a light scattering method in a latex state using a Microtrac particle size distribution measuring device MT3000 manufactured by Nikkiso Co., Ltd.

  Average particle diameter d (nm) of acrylic ester-based crosslinked elastic body in (meth) acrylic resin containing acrylic rubber particles, and amount w of polyfunctional monomer used in acrylic ester-based crosslinked elastic body (Wt%) preferably greatly satisfies the relational expression: 0.02d ≦ w ≦ 0.06d because it greatly affects the elongation at the time of tensile fracture or transparency, and 0.02d ≦ w ≦ 0. It is more preferable to satisfy .05d. If the amount w of the polyfunctional monomer is within the above range, impact resistance is unlikely to be lowered, elongation at the time of tensile breakage is difficult to be lowered, cracks are hardly generated at the time of film cutting, and transparency is hardly lowered. There is an advantage that the property is good.

  The average particle diameter d of the acrylate-based crosslinked elastic body in the (meth) acrylic resin containing acrylic rubber particles is preferably 50 to 200 nm, more preferably 50 to 160 nm, still more preferably 50 to 120 nm, and 60 to 120 nm. Is particularly preferred. If the average particle diameter d of the acrylic ester-based cross-linked elastic body is 50 nm or more, impact resistance and elongation at the time of tensile break are less likely to be reduced, and cracks are less likely to occur when the film is cut. Can be secured, which is preferable.

  The average particle diameter d of the acrylic ester-based cross-linked elastic body is adjusted to a accelerating voltage of 80 kV using a transmission electron microscope (JEM 1200EX, manufactured by JEOL Ltd.) after adjusting the sample from the obtained film by a freezing ultrathin section method. It is a value measured based on a photograph observed at 40000 times.

  The reduced viscosity of the methyl ethyl ketone-soluble component of the (meth) acrylic resin containing acrylic rubber particles is preferably 0.2 to 0.8 dl / g, more preferably 0.2 to 0.7 dl / g, and 0.2 to 0.6 dl / g is more preferable. If it is the said range, the elongation at the time of the tensile fracture of the film obtained does not fall easily, and when a film is cut | disconnected, it is hard to generate | occur | produce a crack. Moreover, it has the advantage that the moldability of a film is favorable.

  Here, the reduced viscosity of the methyl ethyl ketone-soluble component is obtained by dissolving a (meth) acrylic resin containing acrylic rubber particles in methyl ethyl ketone, and then using a standard viscosity tube based on ISO1628-1. It is a value calculated using these values and the solution concentration after measuring the flow time of the solution and the solvent.

  As an initiator in the polymerization of the acrylic ester-based crosslinked elastic body, known initiators such as organic peroxides, inorganic peroxides, and azo compounds can be used. Specifically, t-butyl hydroperoxide, 1,1,3,3-tetramethylbutyl hydroperoxide, succinic acid peroxide, peroxymaleic acid t-butyl ester, cumene hydroperoxide, Organic peroxides such as benzoyl peroxide, sodium formaldehyde sulfoxylate, reducing sugar, ascorbic acid, inorganic peroxides such as potassium persulfate, sodium persulfate, divalent iron salts, and azobisisobutyrate An azo compound such as ronitrile is also used. These may be used alone or in combination of two or more. These initiators are combined with reducing agents such as sodium sulfite, sodium thiosulfate, sodium formaldehyde sulfoxylate, ascorbic acid, hydroxyacetone acid, ferrous sulfate, ferrous sulfate and disodium ethylenediaminetetraacetate It may also be used as a normal redox type initiator.

  Among these, redox combined with inorganic reducing agents such as divalent iron salts and / or organic reducing agents such as formaldehyde sulfoxylate sodium, reducing sugar and ascorbic acid from the viewpoint of polymerization stability and particle size control. It is preferred to use a system initiator.

  The organic peroxide can be added by a known addition method such as a method of adding it as it is to the polymerization system, a method of adding it mixed with a monomer, a method of adding it dispersed in an emulsifier aqueous solution, or the like. From the viewpoint of transparency, a method of adding a mixture to a monomer or a method of adding it by dispersing in an aqueous emulsifier solution is preferable.

  The surfactant used for emulsion polymerization is not particularly limited, and any surfactant for normal emulsion polymerization can be used. For example, anionic surfactants such as sodium alkyl sulfonate, sodium alkylbenzene sulfonate, sodium dioctyl sulfosuccinate, sodium lauryl sulfate, and sodium fatty acid, alkylphenols, aliphatic alcohols and propylene oxide, ethylene oxide Nonionic surfactants such as reaction products are listed. These surfactants may be used alone or in combination of two or more. Furthermore, if necessary, a cationic surfactant such as an alkylamine salt may be used.

  The obtained acrylic rubber particle latex is separated and recovered by ordinary coagulation, washing and drying operations, or by treatment by spray-drying, freeze-drying or the like.

  The (meth) acrylic resin of the present invention can contain a methacrylic polymer (b).

  As the methacrylic polymer (b), a methacrylic ester polymer or a copolymer with another vinyl monomer copolymerizable with the methacrylic ester can be used. Preferably, those obtained by copolymerizing a monomer mixture comprising 80 to 100% by weight of a methacrylic acid ester and 0 to 20% by weight of another copolymerizable vinyl monomer can be used.

  The (meth) acrylic resin is obtained by mixing acrylic rubber particles obtained by polymerization and a methacrylic polymer (b) in the form of latex or powder, beads, pellets, etc. I can do it.

  As the (meth) acrylic resin, a methacrylic polymer (b) produced after the acrylic rubber particles are produced in the same reactor can be used.

  From the viewpoint of the hardness and rigidity of the obtained film, the blending amount of the methacrylic acid ester is more preferably 85% by weight or more, and further preferably 90% by weight or more.

  As said methacrylic acid ester, methacrylic acid alkylester is preferable and methyl methacrylate is more preferable at the point which can be obtained easily.

  Examples of other copolymerizable vinyl monomers in the methacrylic polymer include those used for the acrylic rubber particles. These monomers may be used independently and may use 2 or more types together.

  It is also possible to polymerize the methacrylic polymer (b) separately from the acrylic rubber particles. In this case, the polymerization method is not particularly limited, and a known emulsion polymerization method, emulsion-suspension polymerization method, suspension polymerization method, bulk polymerization method or solution polymerization method can be applied.

  The average particle diameter of the methacrylic polymer (b) is preferably 100 to 500 μm, and more preferably 100 to 300 μm. When the average particle diameter of the methacrylic polymer (a-2) is less than 100 μm, impact resistance, bending cracking resistance, and chemical resistance tend to decrease, and when it exceeds 500 μm, transparency tends to decrease. .

  The average particle diameter of the methacrylic polymer (b) is a value measured by using a light scattering method in a latex state using a Microtrac particle size distribution measuring device MT3000 manufactured by Nikkiso Co., Ltd.

  As an initiator in the polymerization of the methacrylic polymer (b), known organic peroxides, inorganic peroxides, azo compounds, etc., similar to the initiators in the polymerization of the acrylic ester-based crosslinked elastic body described above. Initiators can be used. These may be used alone or in combination of two or more.

  The organic peroxide can be added by a known addition method such as a method of adding it to the polymerization system as it is, a method of adding it by mixing with a monomer, a method of adding it by dispersing in an aqueous emulsifier solution, etc. From the viewpoint of properties, a method of adding to a monomer is preferable.

  Examples of the dispersant used for suspension polymerization include dispersants generally used for suspension polymerization, for example, polymer dispersants such as polyvinyl alcohol, polyvinyl pyrrolidone, and polyacrylamide, calcium phosphate, hydroxyapatite, magnesium pyrophosphate, and the like. The slightly water-soluble inorganic salt of In the case of using a hardly water-soluble inorganic salt, it is effective to use an anionic surfactant such as α-olefin sodium sulfonate or sodium dodecylbenzenesulfonate in order to increase dispersion stability. These dispersants may be added one or more times during the polymerization in order to adjust the particle diameter of the resin particles obtained.

  When the acrylic rubber particles are included, the content of the acrylic rubber particles in the (meth) acrylic resin is preferably 5 to 100% by weight, more preferably 5 to 50% by weight, and still more preferably 10 to 40% by weight. . When the (meth) acrylic resin containing acrylic rubber particles is a resin composition comprising acrylic rubber particles and methacrylic polymer (b), the total of acrylic rubber particles and methacrylic polymer (b) The amount shall be 100% by weight. If the content of the acrylic rubber particles is 5% by weight or more, the elongation at the time of tensile break of the obtained film is difficult to decrease, and cracks tend not to occur when the film is cut. When the content is 5 to 45% by weight, the hardness and rigidity of the obtained film tend to be good.

  For the acrylic resin composition of the present invention, a polycarbonate resin having a melt mass flow rate of 15 g / 10 min to 100 g / 10 min at a temperature of 300 ° C. and a load of 1.2 kgf is used. By using such a polycarbonate resin, high transparency can be maintained. Preferably, it is 20 g / 10 min or more and 90 g / 10 min or less, More preferably, it is 30 g / 10 min or more and 70 g / 10 min or less.

  The melt mass flow rate here is a measured value based on ISO 1133 at a measurement load of 1.2 kgf and a measurement temperature of 300 ° C.

  The amount of the polycarbonate resin used in the present invention is preferably 10 parts by weight or less, more preferably 8 parts by weight or less, and still more preferably 5 parts by weight or less with respect to 100 parts by weight of the (meth) acrylic resin. If the amount is more than 10 parts by weight, the film may become cloudy and the transparency may be lowered.

  In the present invention, a thioxanthene compound is used as the fluorescent dye. Any known thioxanthene compound can be used, and among them, N-octadecyl-benzo [k, 1] thioxanthene-3,4-dicarboximide is preferred.

  Examples of commercially available thioxanthene fluorescent dyes include CI Solvent Yellow 98 (Hostasol YELLOW 3G, Hoechst AG, Frankfurt, Germany).

  A fluorescent dye other than the thioxanthene compound may be used in combination with the acrylic resin composition of the present invention. For example, organic dyes such as coumarin, methine, benzopyran, thioindigo, and anthraquinone and organic pigments such as phthalocyanine can be added. However, the combined use of perylene compounds is not preferred. This is because they tend to be reddish after the accelerated test.

  The use amount of the fluorescent dye of the present invention is preferably 0.01 to 4 parts by weight, more preferably 0.05 to 2 parts by weight, and most preferably 0.4 to 4 parts by weight with respect to 100 parts by weight of the (meth) acrylic resin. 0.8 parts by weight. If it is less than 0.01 part by weight, the desired coloration cannot be obtained, and the fading resistance tends to deteriorate. When the amount is more than 4 parts by weight, a self-quenching phenomenon occurs when the fluorescent dye molecule absorbs energy radiated by the adjacent dye molecule, and there is a tendency that the fluorescent dye does not exhibit fluorescence.

  The method for adding the fluorescent dye of the present invention is not limited to the method of adding the dye powder directly, but may be prepared by adding a masterbatch pellet of a (meth) acrylic resin or a masterbatch pellet of a polycarbonate resin. In producing the master batch, it can be produced by a single-screw or twin-screw extruder, but it is preferably produced by a twin-screw extruder in order to increase dispersibility.

  In the acrylic resin composition of the present invention, an ultraviolet absorber may be used. For example, there are triazine ultraviolet absorbers, 2-hydroxybenzophenone ultraviolet absorbers, salicylic acid phenyl ester ultraviolet absorbers, and benzotriazole compounds, which may be used alone or in combination of two or more. Specific examples of the triazine-based ultraviolet absorber include 2,4-diphenyl-6- (2-hydroxy-4-methoxyphenyl) -1,3,5-triazine, 2,4-diphenyl-6- (2-hydroxy -4-ethoxyphenyl) -1,3,5-triazine, 2,4-diphenyl-6- (2-hydroxy-4-propoxyphenyl) -1,3,5-triazine, 2,4-diphenyl-6 (2-hydroxy-4-butoxyphenyl) -1,3,5-triazine, 2,4-diphenyl-6- (2-hydroxy-4-hexyloxyphenyl) -1,3,5-triazine, 2,4 -Diphenyl-6- (2-hydroxy-4-octyloxyphenyl) -1,3,5-triazine, 2,4-diphenyl-6- (2-hydroxy-4-dodecyloxyphenyl) 1,3,5-triazine, 2,4-diphenyl-6- [2-hydroxy-4- (2-butoxyethoxy) phenyl] -1,3,5-triazine, 2,4-diphenyl-6- (2 -Hydroxy-4-benzyloxyphenyl) -1,3,5-triazine, 2,4-di (4-methylphenyl) -6- (2-hydroxy-4-methoxyphenyl) -1,3,5-triazine 2,4-di (4-methylphenyl) -6- (2-hydroxy-4-ethoxyphenyl) -1,3,5-triazine, 2,4-di (4-methylphenyl) -6- (2 -Hydroxy-4-propoxyphenyl) -1,3,5-triazine, 2,4-di (4-methylphenyl) -6- (2-hydroxy-4-butoxyphenyl) -1,3,5-triazine, 2,4-di (4-methyl) Ruphenyl) -6- (2-hydroxy-4-hexyloxyphenyl) -1,3,5-triazine, 2,4-di (4-methylphenyl) -6- (2-hydroxy-4-octyloxyphenyl) -1,3,5-triazine, 2,4-di (4-methylphenyl) -6- (2-hydroxy-4-dodecyloxyphenyl) -1,3,5-triazine, 2,4-di (4 -Methylphenyl) -6- [2-hydroxy-4- (2-hexyloxyethoxy) phenyl] -1,3,5-triazine, 2,4-bis (2,4-dimethylphenyl) -6- (2 -Hydroxy-4-ethoxyphenyl) -1,3,5-triazine, 2,4-bis (2,4-dimethylphenyl) -6- (2-hydroxy-4-butoxyphenyl) -1,3,5- Triazine, 2, 4 Bis (2,4-dimethylphenyl) -6- (2-hydroxy-4-octyloxyphenyl) -1,3,5-triazine, 2,4-bis (2,4-dimethylphenyl) -6- [2 -Hydroxy-4- (2-hexyloxyethoxy) phenyl] -1,3,5-triazine and the like are exemplified. Specifically, as a benzotriazole ultraviolet absorber, 2,2′-methylenebis [4- (1,1,3,3-tetramethylbutyl) -6- (2H-benzotriazol-2-yl) phenol] 2- (5-methyl-2-hydroxyphenyl) -2H-benzotriazole, 2- [2-hydroxy-3,5-bis (α, α-dimethylbenzyl) phenyl] -2H-benzotriazole, 2- ( 3,5-di-tert-butyl-2-hydroxyphenyl) -2H-benzotriazole, 2- (3-tert-butyl-5-methyl-2-hydroxyphenyl) -5-chloro-2H-benzotriazole, 2 -(3,5-di-tert-butyl-2-hydroxyphenyl) -5-chloro-2H-benzotriazole, 2- (3,5-di-tert-a Examples include mil-2-hydroxyphenyl) -2H-benzotriazole, 2- (2'-hydroxy-5'-tert-octylphenyl) -2H-benzotriazole. Specific examples of 2-hydroxybenzophenone-based ultraviolet absorbers include 2-hydroxy-4-methoxybenzophenone, 2-hydroxy-4-octyloxybenzophenone, 2,4-dihydroxybenzophenone, 2-hydroxy-4-methoxy-4 Examples include '-chlorobenzophenone, 2,2'-dihydroxy-4-methoxybenzophenone, 2,2'-dihydroxy-4,4'-dimethoxybenzophenone and the like. Specific examples of salicylic acid phenyl ester ultraviolet absorbers include p-tert-butylphenyl salicylic acid ester and p-octylphenyl salicylic acid ester.

  The total amount of the ultraviolet absorber of the present invention is preferably 0.5 to 5 parts by weight, more preferably 1 to 5 parts by weight, and most preferably 2 to 4 parts by weight with respect to 100 parts by weight of the (meth) acrylic resin. Part. When the amount is less than 0.5 part by weight, the ultraviolet absorption ability tends to be weak. When the amount is larger than 5 parts by weight, the ultraviolet absorber bleeds from the acrylic resin composition, which tends to be undesirable.

  In the present invention, a hindered amine light stabilizer may be added. As the hindered amine light stabilizer, a known one can be used. For example, tetrakis (1,2,2,6,6-pentamethyl-4-piperidyl) 1,2,3,4-butanetetracarboxylate, bis ( 1,2,2,6,6-pentamethyl-4-piperidyl) [[3,5-bis (1,1-dimethylethyl) -4-hydroxyphenyl] methyl] butyl malonate. You may use individually or in combination of 2 or more types.

  The use amount of the hindered amine light stabilizer of the present invention is preferably 0.5 to 5 parts by weight, more preferably 1 to 5 parts by weight with respect to 100 parts by weight of the (meth) acrylic resin. When the amount is less than 0.5 parts by weight, the light stability tends to be low. When it is larger than 5 parts by weight, the hindered amine light stabilizer tends to bleed from the acrylic resin composition.

  In the acrylic resin composition of the present invention, generally used antioxidants, heat stabilizers, radical trapping agents, catalysts, plasticizers, shrinkage inhibitors, antibacterial / deodorizing agents are used alone or in combination of two or more. You may add in the range which does not impair the objective of invention.

  If necessary, the acrylic resin composition of the present invention may contain polyglutarimide, glutaric anhydride polymer, lactone-cyclized methacrylic resin, polyethylene terephthalate resin, polybutylene terephthalate resin, and the like.

  The fluorescent yellow-green film of the present invention can be obtained by molding an acrylic resin composition. The fluorescent yellow-green film of the present invention has long-term fluorescence maintenance and fading resistance, and also has transparency.

  The fluorescent yellow-green film of the present invention can be produced by a general film forming method, for example, a method in which it is melt-extruded into a film form from a T-die attached to the tip of an extruder. . As an extruder to be used, either a single screw extruder or a twin screw extruder may be used. However, when using a twin-screw extruder, it is preferable to use a quantitative feeder to supply the raw resin for discharge rate control. From the viewpoint of resin pressure control and film forming accuracy, the extruder and die It is preferable to extrude resin through a gear pump.

  If necessary, when forming a film, both sides of the film are brought into contact with a roll or a metal belt at the same time, in particular, by simultaneously bringing into contact with a roll or a metal belt heated to a temperature higher than the glass transition temperature. An excellent film can also be obtained, and the film can be modified by biaxial stretching or the like depending on the purpose.

  The thickness of the fluorescent yellow-green film of the present invention is preferably 30 to 500 μm, more preferably 30 to 300 μm, still more preferably 50 to 200 μm, and most preferably 70 to 150 μm. If it is 30 μm or less or 500 μm or more, the film formability tends to deteriorate.

When the color of the fluorescent yellow-green film of the present invention is measured with 0/45 arrangement, CIE standard light D65 as a light source, (0.479, 0.520), (0.446, 0.483), (0. 512, 0.421) and (0.557, 0.442). A point designated by chromaticity coordinates (x, y), which is a value obtained by measurement, represents the chromaticity of the color stimulus in the CIE color system. Chromaticity coordinates within the region defined by (0.479, 0.520), (0.446, 0.483), (0.512, 0.421) and (0.557, 0.442) ( The chromaticity having x, y) is expressed as yellowish green. The fluorescent yellow-green film of the present invention is preferably within the above range even after 500 hours of accelerated test. Here, the accelerated test means that, according to the method of JIS A 1415, the black panel temperature is 63 ° C. with rain (spray for 12 minutes in 60 minutes) and 50% RH, 550 W / m ^{2 at} 300 to 800 nm. It is exposing light.

  The fluorescent yellow-green film of the present invention can be used for a retroreflective sheet. Used as a protective layer for the reflective element layer of the retroreflective sheet. The reflective element layer is a lens in which a bead or prism-shaped lens is arranged on a resin film. The bead-shaped lens is a reflective lens selected from a spherical resin and glass. The prism-shaped lens is a triangular pyramid or triangular pyramid. It is a reflective lens selected from resin, glass or the like having a shape selected from a base, a quadrangular pyramid, a quadrangular pyramid. It can also be used as a reflective element layer by processing the fluorescent yellow-green film of the present invention into a prism shape.

  The fluorescent yellow-green film of the present invention is a colored film used as a substitute for coating of automotive interior materials, automotive exterior materials, etc. in addition to retroreflective sheets; colored films for building materials such as window frames, bathroom equipment, wallpaper, and flooring materials It can be used as a sundry product, a housing for furniture and electrical equipment, a housing for office equipment such as a facsimile machine, and a colored film used for parts of electrical or electronic equipment. Laminates containing this film include lighting lenses, automobile headlights, optical lenses, optical fibers, optical disks, liquid crystal light guide plates, liquid crystal films, medical products that require sterilization, microwave cooking containers, and home appliances. A housing, toy or recreational product.

  EXAMPLES Next, although this invention is demonstrated further in detail based on an Example, this invention is not limited only to these Examples.

  In the following production examples, examples and comparative examples, “parts” and “%” represent “parts by weight” and “% by weight”, respectively.

In addition, each measuring method of the physical property measured in the following Examples and Comparative Examples is as follows.
(Accelerated test)
The obtained film was fixed to a Teflon (registered trademark) sheet with an aluminum tape as a base, and the test was performed under the following conditions. The execution time was 250 hours and 500 hours in the examples.
Test method: JIS A 1415
Test apparatus: WS type Sunshine carbon arc rod.
Tester: Suga Tester Sunshine Weather Meter WEL-SUN-DCH-B type Test conditions: Black panel temperature: 63 ° C Rain (12 minutes spray in 60 minutes) 50% RH, 550 W / m ^{2 at} 300-800 nm

(Measurement method of color difference)
The color difference between the resulting film and the film after the specified time acceleration test was measured using a 0/45 configuration and evaluated by CIE standard light D65. For the measurement, a spectral color difference meter SE2000 manufactured by Nippon Denshoku Industries Co., Ltd. was used.

(Fade resistance)
The fading resistance of the film before and after the accelerated test was evaluated according to the following criteria.
○: Some color change was observed visually, and (0.479, 0.520), (0.446, 0.483), (0.512, 0.421) and (0.557) were observed in the color difference meter. , 0.442) with chromaticity coordinates (x, y) within the region defined by
Δ: A color change was visually observed, and (0.479, 0.520), (0.446, 0.483), (0.512, 0.421), and (0.557, 0) were observed in the color difference meter. .442) slightly deviating from the chromaticity coordinates (x, y) in the region defined by.
X: A significant color change was observed visually, and (0.479, 0.520), (0.446, 0.483), (0.512, 0.421) and (0.557, 0.442) that deviates considerably from the chromaticity coordinates (x, y) in the region defined by 0.442).

(Fluorescence)
The cross section of the obtained film was confirmed by visual observation, and the one where fluorescent color development could be confirmed was marked as ◯.

The cross section of the film before and after the accelerated test was visually observed, and the fluorescence was evaluated according to the following criteria.
○: Visually little change in fluorescence before and after the accelerated test.
Δ: Fluorescence feeling slightly changed visually before and after the accelerated test.
X: The fluorescence feeling clearly changed before and after the accelerated test visually.

(transparency)
The total light transmittance and haze of the film before and after the acceleration test (250 hours) were measured using a haze meter (Nippon Denshoku Co., Ltd. haze meter NDH-2000 type) according to JIS K7161-1.

(Preparation of acrylic resin composition)
<Acrylic rubber particles (a1-1)>
The following substances were charged into an 8 L polymerization apparatus equipped with a stirrer.
Deionized water 200 parts Sodium dioctylsulfosuccinate 0.25 parts Sodium formaldehyde sulfoxylate 0.15 parts Ethylenediaminetetraacetic acid-2-sodium 0.006 parts Ferrous sulfate 0.00015 parts

  After sufficiently replacing the inside of the polymerization apparatus with nitrogen gas to make it substantially free of oxygen, the internal temperature was set to 60 ° C., 3 parts of methyl methacrylate (MMA), 27 parts of butyl acrylate (BA), allyl methacrylate (AlMA) ) A mixture of 0.4 part and cumene hydroperoxide (CHP) 0.02 part was continuously added at a rate of 15 parts / hour for polymerization. Polymerization was continued for 1 hour after the addition was completed, and the conversion rate of polymerization was set to 98% to obtain an acrylate-based crosslinked elastic body.

  Thereafter, a mixture of 63 parts of MMA, 7 parts of BA, 0.2 part of terrestrial decyl mercaptan (t-DM) and 0.3 part of CHP was continuously added at a rate of 10 parts / hour for polymerization, and further polymerized for 1 hour. Then, the polymerization conversion rate was set to 98% or more to obtain a latex of acrylic rubber particles (a1-1). The obtained latex was salted out and coagulated with calcium chloride, washed with water and dried to obtain a resin powder (a1-1) of acrylic rubber particles.

<Methacrylic polymer (b)>
As the methacrylic polymer (b), methyl methacrylate / methyl acrylate copolymer (Sumitomo Chemical Co., Ltd., Sumipex EX, beads) was used.

(Examples 1-3)
The acrylic rubber particles (a1-1), methacrylic polymer (b), fluorescent dye, polycarbonate, hindered amine light stabilizer and ultraviolet absorber obtained as described above are blended as shown in Table 1 using a Henschel mixer. Mixing at a ratio, an acrylic resin composition was prepared.

  Acrylic resin composition obtained using a 40 mmφ single-screw extruder (manufactured by Osaka Seiki Kogaku Co., Ltd.) with a cylinder temperature adjusted to 200 ° C. to 260 ° C., with a screw speed of 90 rpm and a discharge rate of 15 kg / hour. The product was melt-kneaded, taken up into a strand shape, cooled in a water tank, and then cut using a pelletizer to produce resin pellets of an acrylic resin.

  After drying the resin pellets of acrylic resin for 5 hours or more at 80 ° C., use a 40 mmφ single screw extruder with a film die in which the cylinder temperature was adjusted to 165 to 260 ° C. and the die temperature was adjusted to 240 to 260 ° C. A film having a thickness of 100 μm was prepared.

  When the produced film (film thickness: 100 μm) was measured using a 0/45 arrangement and the color difference was measured with CIE standard light D65, the film was in the CIE 1931 standard color system (0.479, 0.520), ( 0.446, 0.483), (0.512, 0.421) and (0.557, 0.442) had chromaticity coordinates (x, y) within the region.

The polycarbonate resins used are as follows:
B-1: Iupilon H-4000 Melt Mass Flow Rate 63g / 10min (Mitsubishi Engineering Plastics)
B-2: Iupilon H-3000 Melt Mass Flow Rate 30g / 10min (Mitsubishi Engineering Plastics)
B-3: Iupilon S-2000 Melt Mass Flow Rate 10g / 10min (Mitsubishi Engineering Plastics)
B-4: Iupilon E-2000 Melt Mass Flow Rate 5.3g / 10min (Mitsubishi Engineering Plastics)
The fluorescent colorants used were as follows:
Thioxanthene-based fluorescent dye Arimoto Chemical Industries yellow-green fluorescent dye Plast Yellow DY-436
The UVA (ultraviolet absorber) used is as follows:
D-1: Tinuvin 1577 UV absorber (triazine) Ciba Japan D-2: Tinuvin 234 UV absorber (benzotriazole) HALS (hindered amine light stabilizer) used by Ciba Japan is as follows:
Tinuvin 144 hindered amine light stabilizer Weight average molecular weight About 685 g / mol Ciba Japan

  In Comparative Example 1, the initial transparency is high, but the fading resistance and the fluorescence resistance are not good. The films of Comparative Examples 2 and 3 have a slightly improved fading resistance than Comparative Example 1, but the initial fluorescence is not good.

  On the other hand, the films of Examples 1 and 2 are improved in fading resistance and fluorescence resistance and have high initial transparency. In Example 3, further improvement was observed in fading resistance and fluorescence resistance, and the chromaticity coordinates (x, y) in the region defining yellowish green were kept for a long time while maintaining high transparency. be able to.

  From the above, it is clear that according to the acrylic resin composition of the present invention, a film having fluorescence maintenance property and fading resistance for a long time and also having transparency can be obtained.

Claims (12)

  An acrylic resin composition comprising a (meth) acrylic resin, a polycarbonate having a melt mass flow rate of 15 g / 10 min to 100 g / 10 min at a temperature of 300 ° C. and a load of 1.2 kgf, and a thioxanthene compound.   The (meth) acrylic resin contains 50 to 99.9% by weight of an acrylic ester, 0 to 49.9% by weight of another copolymerizable vinyl monomer, and two or more non-polymerizable molecules per molecule. 5 to 85 parts by weight of at least one acrylic ester-based crosslinked elastomer obtained by polymerizing a monomer mixture (a-1) composed of 0.1 to 10% by weight of a polyfunctional monomer having a conjugated double bond 95 to 15 parts by weight of a monomer mixture (a-2) consisting of 50 to 100% by weight of a methacrylic acid ester and 0 to 50% by weight of another copolymerizable vinyl monomer in the presence of The acrylic resin composition according to claim 1, further comprising acrylic rubber particles obtained by copolymerization of -1) and (a-2) in a total amount of 100 parts by weight].   The acrylic resin composition according to claim 1 or 2, wherein the polycarbonate has a content of 10 parts by weight or less based on 100 parts by weight of the (meth) acrylic resin.   A (meth) acrylic resin is a methacrylic polymer obtained by copolymerizing a monomer mixture comprising 80 to 100% by weight of a methacrylic acid ester and 0 to 20% by weight of another copolymerizable vinyl monomer ( The acrylic resin composition according to any one of claims 1 to 3, comprising b).   Furthermore, the acrylic resin composition of any one of Claims 1-4 containing a benzotriazole type compound and / or a triazine type compound as a ultraviolet absorber.   The acrylic resin composition according to any one of claims 1 to 5, further comprising a hindered amine light stabilizer.   The acrylic resin composition according to claim 5 or 6, wherein the content of the ultraviolet absorber is 0.5 to 5 parts by weight with respect to 100 parts by weight of the (meth) acrylic resin.   The acrylic resin composition according to claim 6 or 7, wherein the content of the hindered amine light stabilizer is 0.5 to 5 parts by weight with respect to 100 parts by weight of the (meth) acrylic resin.   A fluorescent yellow-green film formed by molding the acrylic resin composition according to claim 1.   The fluorescent yellow-green film of Claim 9 whose film thickness is 30-300 micrometers.   When measured using a 0/45 arrangement and evaluated with CIE standard light D65, the CIE 1931 standard color system (0.479, 0.520), (0.446, 0.483), (0.512) , 0.421) and (0.557, 0.442) and have chromaticity coordinates (x, y) in the region defined by this standard, even after 250 hours of accelerated testing. Item 11. The fluorescent yellow-green film according to Item 9 or 10.   The fluorescent yellow-green film according to any one of claims 9 to 11, which is used for a retroreflective sheet.