JP2003335956A - Light diffusing resin composition - Google Patents

Abstract

(57) Abstract: Provided is a light-diffusing resin composition which has excellent light-diffusing properties and suppresses a difference in color generated in diffused light depending on an angle. SOLUTION: An average particle diameter of 1 is used as a light diffusing agent in a base resin.
A light-diffusing resin composition in which resin fine particles of about 30 to 30 μm are dispersed.
A light-diffusing resin composition comprising 1 to 20% by mass and 0 to 19.9% by mass of another monomer and having a refractive index lower than that of the base resin.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a light diffusing resin composition, and more specifically, it has excellent light diffusing properties, and a lighting cover, various displays, etc., in which a difference in color caused by diffused light depending on an angle is suppressed. The present invention relates to a light diffusing resin composition that is preferably used.

[0002]

2. Description of the Related Art Conventionally, as a light diffusing member used for lighting covers and various displays, a material in which inorganic or organic fine particles are dispersed in a transparent synthetic resin as a base resin is molded. Things are commonly used. The light diffusing member has a light diffusing property by scattering or reflecting light rays at the interface between the base resin and the fine particles due to the difference in refractive index between the transparent base resin and the fine particles dispersed therein. The method is widely used. Methacrylic resin, polycarbonate, polystyrene, polyvinyl chloride and the like are usually used as the transparent resin in this case.

In the products such as the above-mentioned lighting covers and various displays, it is strongly demanded that the products are brighter and more uniform. Therefore, the light diffusing materials used in these products are more transparent to light and The ability to diffuse light sufficiently is required.

[0004] Conventionally, as a method for obtaining a member having both contradictory performances such as high light transmittance and excellent light diffusion performance, for example, inorganic fine particles such as titanium oxide and glass, polymethylmethacrylate and polystyrene are used. A method of incorporating crosslinked organic fine particles into a base resin as a light diffusing agent has been studied. However, when the inorganic fine particles are used as the light diffusing agent, there are cases in which the light transmittance is likely to decrease, mechanical damage during molding is likely to occur, and light does not diffuse uniformly. When polymethylmethacrylate crosslinked fine particles are used as the organic fine particles and added to the methacrylic resin which is the base resin, the light transmittance is improved, but the difference in refractive index between the two becomes small and satisfactory light diffusion is achieved. There was a problem that the sex was not obtained. On the other hand, when polystyrene crosslinked fine particles are used as the organic fine particles, the light diffusivity is high because the refractive index difference between the organic fine particles and the methacrylic resin as the base resin is large, but the polystyrene crosslinked fine particles have a small Abbe number. Therefore, there is a problem that the difference in Abbe number between the crosslinked fine particles and the methacrylic resin becomes large, and the diffused light causes a color difference depending on the viewing angle.

Further, in Japanese Patent Laid-Open No. 10-67829, a methacrylic resin is dispersed with fine particles of a crosslinked resin composed of methyl methacrylate, styrene and an alkyl acrylate and satisfying specific parameters. It has been proposed that a light diffusing resin having high front brightness can be obtained. However, such a light-diffusing resin has improved front brightness as compared with a resin in which polystyrene cross-linked fine particles are dispersed in a methacrylic resin, but the light-diffusing property is not always satisfactory, and the light-diffusing resin is further improved by market demand. The reality is that there is a need for further improvement.

In addition to the above, a method in which a transparent resin contains cross-linked polymer particles having a refractive index difference and a particle diameter within a specific range (Japanese Patent Laid-Open Nos. 63-291001 and 63-291002). Etc.), a method of containing silicone resin particles having a specific structure and particle diameter (see JP-A-1-172801, JP-A-3-207743, JP-A-3-294348, etc.) and the like are also proposed. However, even in these cases, it was difficult to say that the requirements of the market were sufficiently satisfied in terms of performances such as transparency and diffusivity (especially the difference in color seen depending on the viewing angle).

More recently, there is a strong demand for further increasing the commercial value of light diffusing materials, and when used in lighting covers and various displays, it is required that the light diffusing surface does not have uneven brightness. It is becoming an important point that the image of the light source cannot be seen through.

[0008]

Therefore, an object of the present invention is to diffuse light such as a lighting cover and various displays, which has an excellent light diffusing property and suppresses a color difference generated in the diffused light depending on an angle. An object of the present invention is to provide a resin composition suitable for a member to be formed.

[0009]

As a result of intensive studies to solve the above problems, the present inventor has a lower refractive index than the base resin and has a small difference from the Abbe number of the base resin. The inventors have found that it is effective to use resin fine particles as a light diffusing agent, and have completed the present invention. That is, the present invention includes: 1) An average particle size of 1 to 1 as a light diffusing agent in a base resin.
A light diffusing resin composition in which 30 μm resin fine particles are dispersed, wherein the resin fine particles are 80 to 99.9% by mass of a fluorine-containing (meth) acrylic acid ester and 0.1% of a crosslinkable monomer.
The light-diffusing resin composition is characterized by comprising ˜20 mass% and another monomer 0-19.9 mass% and having a refractive index lower than that of the base resin. The present invention also provides 2) the light-diffusing resin composition as described in 1) above, wherein the base resin is a methacrylic resin, and the resin fine particles have a refractive index of 1.40 to 1.46; The light diffusing resin composition described above is a particle obtained by a polymerization method. Furthermore, the present invention is 3) a molded product comprising the light diffusing resin composition described in 1) or 2) above.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in detail below.
The base resin used in the present invention is not particularly limited, and examples thereof include methacrylic resin, polycarbonate resin, styrene resin, vinyl chloride resin and the like. Among these, methacrylic resin is preferably used in terms of transparency and the like. The methacrylic resin is mainly composed of methyl methacrylate homopolymer, methyl methacrylate, and methyl acrylate, ethyl acrylate, n-propyl acrylate, isopropyl acrylate, butyl acrylate, acrylonitrile, maleic anhydride, styrene, Examples thereof include a copolymer with a copolymerizable monomer such as α-methylstyrene, and the ratio of methyl methacrylate contained in the base resin is preferably 50% by mass or more.
It is more preferably 0% by mass.

The resin fine particles used in the present invention are
Consists of a fluorine-containing (meth) acrylic acid ester, a crosslinkable monomer and, if desired, another monomer. For example, a fluorine-containing (meth) acrylic acid alkyl ester in the presence of a crosslinkable monomer or crosslinkable It is a fine particle composed of a crosslinked vinyl-based copolymer obtained by copolymerizing a monomer with another monomer.

The fluorine-containing (meth) acrylic acid ester is not particularly limited, but for example, a fluorine-containing (meth) acrylic acid alkyl ester (perfluoroalkyl (meth) acrylate) is preferable, and specifically, trifluoroethyl methacrylate, Examples thereof include perfluoroalkyl methacrylate (perfluoroalkyl methacrylate) such as octafluoropentyl methacrylate, and perfluoroalkyl acrylate (perfluoroalkyl acrylate) such as trifluoroethyl acrylate and tetrafluoropropyl acrylate. These are used alone or in combination of two or more, and among these, trifluoroethyl methacrylate and trifluoroethyl acrylate are preferably used.

The above-mentioned fluorine-containing (meth) acrylic acid ester must be used in the range of 80 to 99.9% by mass, based on the total amount of the monomers used, and 82 to 99% by mass.
Is preferably used in the range of, and more preferably in the range of 84 to 96 mass%. When the blending amount of the fluorine-containing (meth) acrylic acid ester is less than 80% by mass,
For example, when a methacrylic resin is used as the base resin, the difference in refractive index from the base resin becomes small and satisfactory light diffusivity cannot be obtained. Therefore, when this is used for a lighting cover or various displays, Disappearing the image of the light source becomes insufficient.

The crosslinkable monomer is not particularly limited, but preferably has two or more unsaturated groups, for example, divinylbenzene, ethylene glycol dimethacrylate, 1,3-butylene glycol dimethacrylate, Examples thereof include divinyl-based monomers such as trimethylolpropane trimethacrylate and allyl methacrylate, and trivinyl-based monomers. These can be used alone or in combination of two or more, and divinylbenzene, ethylene glycol dimethacrylate, trimethylolpropane trimethacrylate and the like are preferably used. The crosslinkable monomer needs to be used in the range of 0.1 to 20% by mass, preferably 1 to 18% by mass, and preferably 4 to 4%, based on the total amount of the monomers used. It is more preferable to use it in the range of 16% by mass. When the compounding amount of the crosslinkable monomer is less than 0.1% by mass, the produced resin fine particles are not sufficiently crosslinked and sufficiently retain their shape when melt-mixed with the base resin. It may not be possible, which is not preferable.

Fluorine-containing (meth) alkyl ester,
Other monomers that can be copolymerized with the crosslinkable monomer,
There is no particular limitation, and examples thereof include other ethylenically unsaturated monomers, and more specifically, olefins such as ethylene, propylene and isobutylene; vinyl chloride,
Halogenated olefins such as vinyl fluoride, vinylidene chloride, vinylidene fluoride; vinyl esters such as vinyl formate, vinyl acetate, vinyl propionate, vinyl versatate; styrene, α-methylstyrene, p-styrene sulfonic acid or the like Styrene-based monomers such as sodium salts and potassium salts; acrylic acid esters such as methyl acrylate and ethyl acrylate; methyl methacrylate,
Methacrylic acid esters such as ethyl methacrylate; N
-Vinylpyrrolidone and the like can be mentioned. These other monomers can be used alone,
It is also possible to use mixtures of these. For example, when a methacrylic resin is used as the base resin, it is preferable to use methyl methacrylate having an Abbe number close to that of the base resin as another monomer. The above-mentioned other monomers are not essential components in the resin fine particles used in the present invention,
It is usually used in the range of 0 to 19.9% by mass, preferably 0 to 17% by mass, more preferably 2 to 12% by mass.
Used in the range of.

The fine resin particles used in the present invention and composed of the above components preferably have an elliptic spherical shape or a spherical shape, and more preferably have a spherical shape. Further, the average particle size thereof needs to be in the range of 1 to 30 μm, preferably 2 to 20 μm,
It is more preferably 2 to 10 μm. When the average particle diameter of the resin fine particles is smaller than 1 μm, the resin composition obtained by dispersing the fine resin particles in the base resin selectively scatters light having a short wavelength, so that the transmitted light tends to be yellowish. Not preferable. On the other hand, when the average particle size exceeds 30 μm, the resin composition obtained by dispersing this in a base resin has a low light diffusivity, and when light passes through the resin, the resin particles are visually recognized as foreign matter. It is not preferable because it becomes easy. The average particle diameter as used herein means the number average particle diameter obtained by actual measurement using a photograph as described later.

The above resin fine particles have an excellent balance between light diffusivity and light transmissivity, and have a particle diameter within a certain range so that the image of the light source due to the parts of the molded product cannot be seen through when the molded product is formed. It is preferable that they are aligned. So, for example,
A coefficient of variation (CV value), which will be described later, as an index showing a good particle size distribution is preferably 50% or less, and 20
% Or less is more preferable.

The resin fine particles used in the present invention are
It is necessary to have a refractive index lower than that of the base resin. When the refractive index of the resin particles is higher than that of the base resin, the light diffusivity is high, but the difference in Abbe number between the base resin and the resin particles is large, and the color varies depending on the angle at which the diffused light is viewed. Is likely to occur, which is not preferable. Therefore, the difference in the refractive index between the base resin and the resin fine particles is usually preferably not too small or too large. For example, when a methacrylic resin is used as the base resin, the refractive index of the resin fine particles is Is 1.40
It is preferable to use a material of about 1.46.

The resin fine particles used in the present invention can be usually produced by an aqueous suspension polymerization, but the production method is not particularly limited, and for example, in a batch type reaction vessel, polymerization is performed from particle formation to polymerization. Method of consistently performing until completion; a step of continuously supplying a monomer mixture to a granulator to obtain a suspension having a droplet group of a desired size, and the suspension from the granulator. A suspension polymerization method comprising a step of taking out and introducing into a polymerization tank to complete a polymerization reaction to obtain polymer particles (see, for example, JP-A-6-157619); a step of dispersing a monomer mixture And a step of adding the dispersion obtained in that step to water and polymerizing it (see, for example, JP-A-6-211907); using the Shirasu-porous glass (SPG) method , The monomer mixture to be the dispersed phase By press-fitting to the aqueous phase solution comprising a continuous phase through the micro porous membrane having pores, to obtain a suspension having a desired uniform particle diameter step (JP-A-2
-95433) and the step of introducing the suspension into a polymerization tank and completing the polymerization reaction to obtain polymer particles. Among these methods, the method described at the end, a method of producing by a so-called film emulsion polymerization method, it is possible to make the particle diameter of the resin fine particles in a narrow range, excellent light diffusibility and prevent transmission of the light source image. It is preferably adopted from the viewpoint of being able to do so.

Examples of the polymerization initiator used when the resin fine particles used in the present invention are produced by aqueous suspension polymerization include, for example, acyloyl peroxide such as benzoyl peroxide and lauroyl peroxide; cumene hydroperoxide, t-butyl. Alkyl peresters such as perbenzoate and i-propyl peracetate; dialkyl peroxides such as di-t-butyl peroxide; azobisisobutyronitrile, azobiscyclohexanecarbonitrile,
Examples thereof include azobisacrylonitrile such as 2,2-azobis-2,4-dimethylvaleronitrile. In addition to the above, a redox-based polymerization initiator in which a peroxide and a reducing agent are combined, α, α-dimethoxy-α-
Monofolinomethyl thiophenyl acetophenone,
Photopolymerization initiators such as 2,4,6-trimethylbenzoylphosphine oxide, benzophenone, thioxanthone, and tetramethylthiuram monosulfide can also be used. The amount of the polymerization initiator used is usually 0.05 to 10 parts by mass, preferably 0.5 to 3 parts by mass, based on 100 parts by mass of the total amount of the monomers used.

Water is usually used as a solvent when the resin fine particles used in the present invention are produced in the aqueous suspension polymerization, but ethylene glycol, glycerin ethanol, methanol and the like can also be used. It can also be used together. Further, it is preferable to add a surfactant, a suspension stabilizer and the like to the above solvent. In particular, when a suspension stabilizer is used, it is preferable that an agglomerate is not generated during polymerization and polymer particles having a more uniform particle size can be obtained.

Examples of the above surfactants include anionic surfactants such as sodium dodecylbenzenesulfonate, sodium lauryl sulfate, sodium dialkylsulfosuccinate, and formalin condensates of naphthalenesulfonic acid; alkylammonium salts, alkylbenzylammonium salts. , Betaine, imidazolium betaine, lecithin, and other cationic surfactants; polyoxyethylene nonylphenol ether, polyethylene glycol monostearate, sorbitan monostearate, and other nonionic surfactants. From the viewpoint of the stability of the suspension, etc., the amount of these surfactants to be used is usually preferably in the range of 0.1 to 10 mass% with respect to the total amount of the solvent used. Examples of the suspension stabilizer include hydrophilic synthetic polymer substances such as polyvinyl alcohol, polyvinyl pyrrolidone, and polyethylene glycol; organic suspension stabilizers such as hydrophilic semi-synthetic polymer substances such as carboxymethyl cellulose; Phosphates such as magnesium, barium, calcium, calcium carbonate,
Inorganic suspension stabilizers such as magnesium carbonate, zinc oxide, aluminum oxide, and aluminum hydroxide can be used. From the viewpoint of stability of the suspension, the amount of these suspension stabilizers added is usually 0.1 with respect to the total amount of the continuous phase liquid.
It is preferably used in the range of 20 to 20% by mass.

The amount of the monomer added in the above aqueous suspension polymerization is usually 1 to 100 parts by weight with respect to 100 parts by weight of the aqueous solvent from the viewpoints of productivity, homogeneity of particle size, and the like.
It is preferably 1 to 30 parts by mass.

The method of blending the resin fine particles with the base resin is not particularly limited, and for example, the resin fine particles are mixed in advance with the base resin pellets, and the mixture is extruded or injection-molded into pellets or the like. Method for preparing light-diffusing resin composition; Method for forming resin by adding resin fine particles during extrusion or injection molding of base resin to form light-diffusing resin composition in the form of pellets; once base resin and resin It is possible to employ a method in which the base resin and the masterbatch product are extruded or injection-molded again after the fine particles are masterbatched to obtain a light diffusing resin composition in the form of pellets or the like. The addition ratio of the resin fine particles to the base resin may be a small amount as long as the effects of the present invention are exhibited, and is not particularly limited, but is usually 0.5 to 10 parts by mass with respect to 100 parts by mass of the base resin. ,
It is preferably 1 to 8 parts by mass.

The thus obtained light diffusing resin composition of the present invention can be subjected to various molding methods such as those applied to ordinary thermoplastic resins, whereby molding of any shape and size is carried out. The body can be manufactured. The molding method is not particularly limited, and for example, extrusion molding,
Injection molding, blow molding, calendar molding, press molding,
Various molding methods such as melt spinning can be adopted. Also,
It is also possible to directly add the resin fine particles used in the present invention to the base resin-forming monomer at the time of cast molding and mix them, and polymerize and mold them into a plate, a film, another molded body or the like. Further, in order to enhance the commercial value of the obtained molded product as a product, other additives such as an inorganic pigment and a light stabilizer can be added in a small amount within the range where the object of the present invention is achieved. Further, for the purpose of adjusting the brightness of the molded product which is a product, it is possible to process the surface of the molded product with a mat, a prism, an optical pattern or the like.

[0026]

The present invention will be described in more detail below with reference to examples, but the present invention is not limited thereto. In the examples, "%" and "parts" are "mass%" and "parts by mass", respectively, unless otherwise specified.

The measuring methods and methods for evaluating various physical properties in the examples are shown below. (1) Number average particle size of resin fine particles and coefficient of variation (CV
Values) The resin fine particles obtained in Examples and Comparative Examples are observed with a scanning electron microscope (SEM), and the particle diameter of 200 particles is actually measured using the obtained photographs to obtain the number average particle diameter. The standard deviation for the number average particle diameter was calculated. As a particle size distribution index, the coefficient of variation (CV value) expressed as a percentage (%) was determined by the following formula. CV = (standard deviation with respect to number average particle diameter / number average particle diameter) × 100

(2) General optical characteristics (total light transmittance and haze value) The general optical characteristics (total light transmittance and haze value) of the molded test piece are measured by a haze meter (DIGITAL HASE C).
OMPUTER; manufactured by Suga Test Instruments Co., Ltd.).

(3) Frontal Brightness The frontal brightness of the molded test piece was measured by the following method using the following light source. Illumination light source: cold cathode tube (surface brightness: 11430 cd / cm
² ) was used. Measurement arrangement and measurement method: A molding test piece having a width of 50 mm was placed at a distance of 5 mm from the surface of the cold cathode tube, and a luminance meter (BM-5A; manufactured by Topcon Corporation) was placed at a position 1 m away from the surface of the molding test piece. It was fixed and the front luminance was measured.

(4) Disappearance of light source image When measuring the above-mentioned front luminance, the disappearance of the light source image is visually observed on the surface of the molding test piece on the side opposite to the light source. It was evaluated by. ◯: Light source image disappeared △: Light source image blurred ×: Light source shape clearly recognizable

(5) Angle Dependence of Luminance Ratio and Color Temperature The angle dependence of the luminance ratio and color temperature of the molded test piece was measured by the following arrangement and method using the following light source. Light source: An illumination light source PHL-50 (manufactured by Mejiro Precision Co., Ltd.) was used. Measurement arrangement: In order to make the light from the light source parallel light, a lens was installed 70 mm away from the illumination light source. 50 from the lens
Molded test pieces separated by mm (120 mm length × 120 mm width ×
A flat plate having a thickness of 2 mm) was fixedly installed on a rotary stage, and a luminance meter (BM-5A; manufactured by Topcon Corporation) was fixed at a position 700 mm away from the surface of the molded test piece. Measuring method: With the line connecting the illumination light source and the luminance meter as the center line,
Fix the molded test piece in the direction perpendicular to the center line (2 mm
The plate thickness direction was fixed so that light could be transmitted), and the angle was set to 0 degree. The brightness and color temperature in this state were measured, and then the brightness value and color temperature of the molded test piece were measured at intervals of 5 degrees while rotating the rotary stage. Next, the brightness ratio was calculated as a percentage (%) by dividing the brightness value obtained at 5 ° intervals by the above by the brightness value obtained at an angle of 0 °.

(6) Refractive Index of Resin Fine Particles 1 part of 2,2-azobis-2,4-dimethylvaleronitrile was dissolved in 100 parts of the monomer component constituting the resin fine particles shown in Examples and Comparative Examples. This melt 1
After injecting into a glass mold of 50 mm × width 50 mm × thickness 1 mm, the temperature was raised from 40 ° C. to 80 ° C. over 5 hours for polymerization, and further 100 ° C. for 1 hour. After cooling the obtained polymer, it was peeled from the glass mold to obtain a refractive index test piece. The test piece was measured with a refractometer (RX-
2000; manufactured by Atago Co., Ltd.), and the obtained refractive index was defined as the refractive index of the resin fine particles.

(7) Refractive index of base resin The base resin has a refractive index of 150 mm length × 50 width.
After inserting into a mold of mm x thickness 1 mm, molding temperature 23
Compression molding at 0 ℃ (Desktop test press, Shinto Metal Industry Co., Ltd.)
Then, the obtained molded body was cooled and then taken out of the mold to obtain a refractive index test piece. The test piece was measured with a refractometer (RX-200
0; manufactured by Atago Co., Ltd.) was used to measure the refractive index of the base resin.

Example 1 (1) The following components were mixed to prepare a dispersed phase liquid. Monomer component: 2,2,2-trifluoroethyl methacrylate 66.5 g (V-3FM; manufactured by Osaka Organic Chemical Co., Ltd.) ethylene glycol dimethacrylate 3.5 g Chain transfer agent: dodecyl mercaptan 0.35 g Polymerization initiator Lauryl peroxide 0.42 g (2) Next, the following components were dissolved and mixed to prepare a continuous phase liquid. Distilled water 450 g Polyvinyl alcohol 2.93 g (PVA-217; manufactured by Kuraray Co., Ltd.) Sodium lauryl sulfate 0.15 g Sodium hydrogen sulfate 0.23 g Sodium nitrite 0.375 g (3) Cylindrical porous glass (pore size 0 0.54 μm, diameter 10 mm, length 20 mm) mounted on the membrane module A,
After adding the dispersed phase liquid and the continuous phase liquid to each tank of the membrane emulsification device (FIG. 1) including the nitrogen gas cylinder B, the dispersed phase liquid storage tank C, the continuous phase liquid circulation tank D, etc., the inside of the porous glass is continuously filled. The phase liquid is circulated, and then the dispersed phase liquid is supplied from the outside of the cylindrical porous glass to 0.095 MPa (95 KP
The emulsion was obtained by press-fitting into the cylinder due to the pressure difference of a). The emulsion thus obtained has a volume of 100
The mixture was placed in a 0 ml separable flask and polymerization was carried out at a temperature of 75 ° C. for 6 hours while stirring the suspension under a nitrogen atmosphere at a rotation speed of 130 rpm to produce resin fine particles. The obtained dispersion liquid of resin fine particles is left for one day, decanted, washed, dehydrated and dried to obtain resin fine particles (P-
1) was isolated. The number average particle diameter of the obtained resin fine particles was 5.5 μm, the coefficient of variation (CV value) was 16.0%, the refractive index was 1.440, and it was confirmed that the fine particles were true spherical particles. . The polymerization yield (polymer yield relative to the charged amount of monomer) in this reaction was 99%. Further, using the resin fine particles, a molding test piece was prepared as follows, the obtained molding test piece was evaluated, and the obtained total light transmittance, haze, front brightness and the disappearance state of the light source image were evaluated. Is shown in Table 1, the angle dependency of the luminance ratio is shown in Table 2, and the angle dependency of the color temperature is shown in Table 3.

(Preparation of Molded Test Piece) 2.4 g of the resin fine particles (P-1) obtained above and methacrylic resin (Parapet EH; manufactured by Kuraray Co., Ltd .; refractive index 1.495) 57.6.
g and mix and prepare, and Labo Plastomill (LABO PLA
STOMILL; manufactured by Toyo Seiki Seisakusho Co., Ltd.) was melt-kneaded under the conditions of 230 ° C., 8 min and 60 rpm to prepare a light diffusing resin composition. The light diffusing resin composition was compression molded at 230 ° C. and 5 MPa using a mold having a length of 150 mm × width of 50 × thickness of 2 mm (desktop test press:
(Manufactured by Shinto Metal Industry Co., Ltd.) to obtain a molding test piece.

Example 2 (1) The following components were mixed to prepare a dispersed phase liquid. Monomer component: 2,2,2-trifluoroethyl methacrylate 59.5 g (V-3FM; manufactured by Osaka Organic Chemical Co., Ltd.) Methyl methacrylate 7.0 g Ethylene glycol dimethacrylate 3.5 g Chain transfer agent: Dodecyl mercaptan 0.35 g Polymerization initiator: Lauryl peroxide 0.42 g (2) Next, the following components were dissolved and mixed to prepare a continuous phase liquid. Distilled water 450 g Polyvinyl alcohol 2.93 g (PVA-217; manufactured by Kuraray Co., Ltd.) Sodium lauryl sulfate 0.15 g Sodium hydrogen sulfate 0.23 g Sodium nitrite 0.375 g (3) The above-mentioned dispersed phase liquid and continuous phase liquid Using the dispersed phase liquid from the outside of the cylindrical porous glass at 0.038 MPa (38
Example 1 except that the pressure difference of KPa) is applied to the inside of the cylinder.
An emulsion was obtained and resin fine particles were produced in the same manner as in (3). The number average particle diameter of the obtained resin fine particles (P-2) was 6.5 μm, the coefficient of variation (CV value) was 10.5%,
The refractive index was 1.446, and it was confirmed that the fine particles were true spherical particles. The polymerization yield in this reaction is 9
It was 9.5%. Further, in the same manner as in (3) of Example 1, after producing a molding test piece composed of 3.6 g of the resin fine particles (P-2) and 56.4 g of the methacrylic resin, the obtained molding test piece was evaluated. Table 1 shows the total light transmittance, haze, front luminance, and disappearance of the light source image obtained.
Table 2 shows the angle dependence of the luminance ratio, and Table 3 shows the angle dependence of the color temperature.

Comparative Example 1 (1) The following components were mixed to prepare a dispersed phase liquid. Monomer component: 2,2,2-trifluoroethyl methacrylate 21.0 g (V-3FM; manufactured by Osaka Organic Chemical Co., Ltd.) Methyl methacrylate 45.5 g Ethylene glycol dimethacrylate 3.5 g Chain transfer agent: Dodecyl mercaptan 0 .35 g Polymerization initiator: Lauryl peroxide 0.42 g (2) Next, the following components were mixed and dissolved to prepare a continuous phase liquid. Distilled water 450 g Polyvinyl alcohol 2.93 g (PVA-217; manufactured by Kuraray Co., Ltd.) Sodium lauryl sulfate 0.15 g Sodium hydrogensulfate 0.23 g Sodium nitrite 0.375 g (3) Using the above dispersed phase liquid and continuous phase liquid , A dispersed phase liquid of 0.033 MPa (33
Example 1 except that the pressure difference of KPa) is applied to the inside of the cylinder.
An emulsion was obtained in the same manner as in (3), and then resin fine particles were produced. The obtained resin fine particles (P-3) have a number average particle diameter of 8.5 μm and a coefficient of variation (CV value) of 16.5.
%, The refractive index was 1.465, and it was confirmed that the fine particles were spherical particles. The polymerization yield in this reaction was 98%. Further, in the same manner as in (3) of Example 1, after forming a molding test piece composed of 4.8 g of the resin fine particles (P-3) and 55.2 g of the methacrylic resin, the obtained molding test piece was evaluated. The total light transmittance, haze, front luminance and disappearance of the light source image are shown in Table 1, the angle dependence of the luminance ratio is shown in Table 2, and the color temperature angle dependence is shown in Table 3.

Comparative Example 2 In the same manner as in Example 1, the resin fine particles (P-3) 2.
After producing a molded test piece composed of 4 g and 57.6 g of methacrylic resin, the molded test piece obtained was evaluated, and the total light transmittance, haze, frontal luminance and disappearance of the light source image are shown in Table 1 and the luminance. Table 2 shows the angle dependence of the ratio, and Table 3 shows the angle dependence of the color temperature.

Comparative Example 3 (1) The following components were mixed to prepare a dispersed phase liquid. Monomer component: Styrene 14.0 g Methyl methacrylate 49.0 g Divinylbenzene 7.0 g Chain transfer agent: Dodecyl mercaptan 0.28 g Polymerization initiator: Lauryl peroxide 0.42 g (2) Then, the following components are mixed and dissolved. A continuous phase liquid was prepared. Distilled water 450 g Polyvinyl alcohol 2.93 g (PVA-217; manufactured by Kuraray Co., Ltd.) Sodium lauryl sulfate 0.15 g Sodium hydrogensulfate 0.23 g Sodium nitrite 0.375 g (3) Using the above dispersed phase liquid and continuous phase liquid , The dispersed phase liquid from the outside of the cylindrical porous glass to 0.023 MPa (23 K
An emulsion was obtained in the same manner as in (3) of Example 1 except that pressure was applied to the inside of the cylinder by the pressure difference of Pa), and then resin fine particles were produced. The obtained resin fine particles (P-4) have a number average particle diameter of 5.0 μm and a coefficient of variation (CV value) of 10.3.
%, The refractive index was 1.525, and it was confirmed that the fine particles were spherical particles. The polymerization yield in this reaction was 98%. Further, in the same manner as in Example 1, 0.7 g of the resin fine particles (P-4) and methacrylic resin 5 were used.
After producing a molded test piece of 9.3 g, the molded test piece obtained was evaluated, and the total light transmittance, haze, frontal luminance, and disappearance of the light source image are shown in Table 1, and the luminance ratio depends on the angle. Table 2 shows the characteristics, and Table 3 shows the angle dependence of color temperature.
Are shown respectively.

Comparative Example 4 Techpolymer SBX-12 (manufactured by Sekisui Chemical Co., Ltd., commercially available as a styrene-based light diffusing agent, refractive index 1.5)
95) 1.8 g and a methacrylic resin (EH-P; manufactured by Kuraray Co., Ltd .; refractive index 1.495) 57.2 g were used in the same manner as in Example 1 except that a molding test piece (2 mm flat plate) was obtained. . The obtained molded test piece was evaluated, and the total light transmittance, haze, front luminance and disappearance of the light source image are shown in Table 1, the angle dependence of the luminance ratio is shown in Table 2, and the angle of the color temperature. The dependencies are shown in Table 3, respectively.

[0041]

[Table 1]

[0042]

[Table 2]

[0043]

[Table 3]

[0044]

EFFECTS OF THE INVENTION As is clear from the above, the molded product produced using the light diffusing resin composition of the present invention is bright because of its high light transmittance, and is excellent in light diffusing property. Is invisible, and the color difference generated in the diffused light depending on the angle is suppressed, which is extremely excellent. Therefore, the light diffusing resin composition obtained by the present invention is widely and suitably used for lighting covers, various displays, and the like.

[Brief description of drawings]

FIG. 1 is a schematic view of a film emulsification device used in Examples and Comparative Examples.

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Claims (4)

[Claims] 1. An average particle size of 1 as a light diffusing agent in a base resin.
A light diffusing resin composition in which resin fine particles having a particle size of 30 μm to 30 μm are dispersed, wherein the resin fine particles contain 80 to 99.9% by mass of a fluorine-containing (meth) acrylic acid ester and a crosslinkable monomer of 0.1.
A light diffusing resin composition comprising 1 to 20% by mass and 0 to 19.9% by mass of another monomer and having a refractive index lower than that of the base resin. 2. The light diffusing resin composition according to claim 1, wherein the base resin is a methacrylic resin and the resin fine particles have a refractive index of 1.40 to 1.46. 3. The light diffusing resin composition according to claim 1 or 2, wherein the resin fine particles are particles obtained by a film emulsion polymerization method. 4. A molded product comprising the light diffusing resin composition according to claim 1.