KR20200137939A - Thermoplastic resin composition and light diffusion sheet produced therefrom - Google Patents

Abstract

A thermoplastic resin composition of the present invention contains: 100 parts by weight of a polycarbonate resin; and 0.5 to 3 parts by weight of polystyrene-polymethylmethacrylate copolymer particles, wherein the polystyrene-polymethylmethacrylate copolymer particles have a polystyrene content of 41 to 59 wt%, a polymethylmethacrylate content of 41 to 59 wt%, an average particle diameter of 3 to 9 μm, and the coefficient of variation (CV) of the particle diameter of 20 to 40. The thermoplastic resin composition is excellent in light transmittance, light diffusion, and balance of physical properties thereof.

Description

Thermoplastic resin composition and light diffuser plate formed therefrom {THERMOPLASTIC RESIN COMPOSITION AND LIGHT DIFFUSION SHEET PRODUCED THEREFROM}

The present invention relates to a thermoplastic resin composition and a light diffusion plate formed therefrom. More specifically, the present invention relates to a thermoplastic resin composition excellent in light transmittance, light diffusivity, and balance of physical properties thereof, and a light diffusion plate formed therefrom.

In general, LED (light emitting device) lighting has strong linearity of light due to the characteristics of LED, and when using it as lighting, it is necessary to disperse LED light that goes straight using a light diffusion plate.

The light diffusing plate (cover) for lighting mainly uses polycarbonate resin as the main resin in consideration of transparency, moldability and flame retardancy, and silicone or acrylic light diffusing agent is dispersed in the resin to increase the degree of light dispersion.

However, in the case of the existing light diffusion plate product, as the light diffusivity increases, the light transmittance decreases, and thus there is a limit to use as a light diffusion plate for lighting.

Accordingly, there is a need to develop a thermoplastic resin composition having excellent light transmittance, light diffusivity, and balance of properties thereof, and a light diffusion plate (for lighting) formed therefrom.

The background technology of the present invention is disclosed in Korean Patent Application Publication No. 2016-0141078 and the like.

An object of the present invention is to provide a thermoplastic resin composition excellent in light transmittance, light diffusivity, and balance of properties thereof.

Another object of the present invention is to provide a light diffusion plate formed from the thermoplastic resin composition.

All of the above and other objects of the present invention can be achieved by the present invention described below.

1. One aspect of the present invention relates to a thermoplastic resin composition. The thermoplastic resin composition includes 100 parts by weight of a polycarbonate resin; And 0.5 to 3 parts by weight of polystyrene-polymethylmethacrylate copolymer particles, and the polystyrene-polymethylmethacrylate copolymer particles have a polystyrene content of 41 to 59% by weight, and a polymethylmethacrylate content of 41 to It is characterized in that it is 59% by weight, has an average particle diameter of 3 to 9 µm, and a coefficient of variation (CV) of the particle size according to the following formula 1 is 20 to 40:

[Equation 1]

Coefficient of variation (CV) = [σ / M]

In Formula 1, M is the average particle diameter of the copolymer particles, and σ is the standard deviation of the particle diameter of the copolymer particles.

2. In the first embodiment, the polycarbonate resin may have a weight average molecular weight of 20,000 to 30,000 g/mol.

3. In the above 1 or 2 embodiment, the thermoplastic resin composition may have a transmittance of 96% or more of a 1.0 mm thick specimen measured according to ASTM D1003, and a transmittance of 92% or more of a 2.0 mm thick specimen.

4. In the above embodiments 1 to 3, the thermoplastic resin composition may have an angle of 3 to 20°, which is half of the light intensity value at 0° measured using a variable angle photometer, for a 1.0 mm thick specimen, and , For a 2.0 mm thick specimen, the angle of the luminous intensity value, which is half of the luminous intensity value at 0° measured using a variable angle photometer, may be 10 to 30°.

5. Another aspect of the present invention relates to a light diffusion plate. The light diffusion plate is characterized in that it is formed from the thermoplastic resin composition according to any one of the above 1 to 4.

6. Another aspect of the present invention relates to a light diffusion plate. The light diffusing plate is a light diffusing plate in which a light diffusing agent is dispersed in a polycarbonate resin matrix, the light diffusing agent includes polystyrene-polymethylmethacrylate copolymer particles, and the polystyrene-polymethylmethacrylate copolymer particles Is characterized in that the average particle diameter is 3 to 9 μm, and the coefficient of variation of the particle diameter (coefficient　of　variation: CV) according to the following formula 1 is 20 to 40:

[Equation 1]

Coefficient of variation (CV) = [σ / M]

In Formula 1, M is the average particle diameter of the copolymer particles, and σ is the standard deviation of the particle diameter of the copolymer particles.

7. In the sixth embodiment, the light diffusion plate is 100 parts by weight of the polycarbonate resin matrix; And 0.5 to 3 parts by weight of the light diffusing agent.

8. In the 6 or 7 embodiment, the light diffusion plate may have a transmittance of 96% or more of a 1.0 mm thick specimen measured according to ASTM D1003, and a transmittance of 92% or more of a 2.0 mm thick specimen.

9. In the above 6 to 8 embodiments, the light diffusing plate may have an angle of 3 to 20°, which is half of the light intensity value at 0° measured using a variable angle photometer, for a 1.0 mm thick specimen, , For a 2.0 mm thick specimen, the angle of the luminous intensity value, which is half of the luminous intensity value at 0° measured using a variable angle photometer, may be 10 to 30°.

The present invention has the effect of the present invention to provide a thermoplastic resin composition excellent in light transmittance, light diffusivity, and balance of properties thereof, and a light diffusion plate formed therefrom.

Hereinafter, the present invention will be described in detail.

The thermoplastic resin composition according to the present invention includes (A) a polycarbonate resin; And (B) polystyrene-polymethylmethacrylate copolymer particles.

In the present specification, "a to b" representing a numerical range is defined as "≥a and ≤b".

(A) Polycarbonate resin

As the polycarbonate resin according to an embodiment of the present invention, a polycarbonate resin used in a conventional thermoplastic resin composition may be used. For example, an aromatic polycarbonate resin prepared by reacting diphenols (aromatic diol compounds) with a precursor such as phosgene, halogen formate, or carbonic acid diester can be used.

In a specific embodiment, the diphenols include 4,4'-biphenol, 2,2-bis(4-hydroxyphenyl)propane, 2,4-bis(4-hydroxyphenyl)-2-methylbutane, 1 ,1-bis(4-hydroxyphenyl)cyclohexane, 2,2-bis(3-chloro-4-hydroxyphenyl)propane, 2,2-bis(3,5-dichloro-4-hydroxyphenyl) Propane and the like may be exemplified, but are not limited thereto. For example, 2,2-bis(4-hydroxyphenyl)propane, 2,2-bis(3,5-dichloro-4-hydroxyphenyl)propane, or 1,1-bis(4-hydroxyphenyl) ) Cyclohexane can be used, and specifically, 2,2-bis(4-hydroxyphenyl)propane called bisphenol-A can be used.

In specific embodiments, the polycarbonate resin may be used having a branched chain, for example, with respect to the total diphenols used in polymerization, 0.05 to 2 mol% of a trivalent or higher polyfunctional compound, specifically, 3 It is also possible to use a branched polycarbonate resin prepared by adding a compound having a phenol group having a phenolic group or higher.

In a specific embodiment, the polycarbonate resin may be used in the form of a homopolycarbonate resin, a copolycarbonate resin, or a blend thereof. In addition, the polycarbonate resin may be partially or entirely replaced with an aromatic polyester-carbonate resin obtained by polymerization reaction in the presence of an ester precursor, such as a bifunctional carboxylic acid.

In a specific example, the polycarbonate resin may have a weight average molecular weight (Mw) measured by gel permeation chromatography (GPC) of 20,000 to 30,000 g/mol, for example, 20,000 to 25,000 g/mol. Within the above range, the fluidity (processability) of the thermoplastic resin composition may be excellent.

In a specific example, the polycarbonate resin may have a melt-flow index (MI) of 10 to 40 g/10 minutes measured under a load condition of 300°C and 1.2 kg according to ISO 1133. In addition, the polycarbonate resin may be a mixture of two or more polycarbonate resins having different melt flow indexes.

(B) Polystyrene-polymethylmethacrylate copolymer particles

The polystyrene-polymethyl methacrylate copolymer particles according to the present invention are applied together with a polycarbonate resin to improve both light transmittance and light diffusivity, and prepare conventional polystyrene-polymethyl methacrylate copolymer particles. Depending on the method, it may be prepared by mixing styrene and methyl methacrylate and polymerizing it by a known polymerization method, and the polystyrene content may be 41 to 59% by weight, for example, 45 to 55% by weight, and polymethyl The methacrylate content may be 41 to 59% by weight, for example 45 to 55% by weight. When the polystyrene content of the polystyrene-polymethylmethacrylate copolymer particles is less than 41% by weight (polymethylmethacrylate content is more than 59% by weight), there is a concern that the transmittance of the thermoplastic resin composition may decrease, and polystyrene When the content exceeds 59% by weight (polymethylmethacrylate content is less than 41% by weight), there is a concern that the light transmittance, light diffusivity, etc. of the thermoplastic resin composition may be deteriorated.

In a specific example, the polystyrene-polymethylmethacrylate copolymer particles have an average particle diameter (D50) of 3 to 9 μm, for example 4 to 7 μm, as measured by a particle size analyzer (manufacturer: Beckman Coulter, device name: Multisizer 4). May be, and a coefficient of variation (CV) of the particle diameter according to Equation 1 below may be 20 to 40, for example, 30 to 40.

[Equation 1]

Coefficient of variation (CV) = [σ / M]

In Formula 1, M is the average particle diameter of the copolymer particles, and σ is the standard deviation of the copolymer particles.

When the average particle diameter of the polystyrene-polymethylmethacrylate copolymer particles is less than 3 μm, there is a concern that the light diffusibility of the thermoplastic resin composition may be lowered, and when it exceeds 9 μm, the light transmittance of the thermoplastic resin composition, light There is a concern that diffusivity and the like may be deteriorated.

In addition, when the coefficient of variation of the polystyrene-polymethylmethacrylate copolymer particles is less than 20, the light transmittance and light diffusion properties of the thermoplastic resin composition may be deteriorated, and when it exceeds 40, the light of the thermoplastic resin composition There is a concern that transmittance, light diffusivity, and the like may be deteriorated.

In a specific embodiment, the polystyrene-polymethylmethacrylate copolymer particles have a weight average molecular weight (Mw) of 20,000 to 30,000 g/mol, for example, 20,000 to 25,000 g/mol, as measured by gel permeation chromatography (GPC). I can. In the above range, the optical properties and thermal stability of the thermoplastic resin composition may be excellent.

In a specific embodiment, the polystyrene-polymethylmethacrylate copolymer particles may be included in an amount of 0.5 to 3 parts by weight, for example, 1 to 2 parts by weight, based on 100 parts by weight of the polycarbonate resin. When the content of the polystyrene-polymethylmethacrylate copolymer particles is less than 0.5 parts by weight, the light transmittance and light diffusibility of the thermoplastic resin composition may be deteriorated, and when it exceeds 3 parts by weight, the light of the thermoplastic resin composition There is a concern that transmittance, light diffusivity, and the like may be deteriorated.

The thermoplastic resin composition according to an embodiment of the present invention may further include an additive included in a conventional thermoplastic resin composition within a range that does not impair the effect of the present invention. Examples of the additives include antioxidants, lubricants, flame retardants, anti-drip agents, release agents, nucleating agents, stabilizers, pigments, dyes, mixtures thereof, and the like, but are not limited thereto. When using the additive, the content may be 0.001 to 40 parts by weight, for example, 0.1 to 10 parts by weight, based on 100 parts by weight of the polycarbonate resin.

The thermoplastic resin composition according to an embodiment of the present invention may be in the form of pellets obtained by mixing the above constituents and melt-extruding at 220 to 300°C, for example, 240 to 280°C using a conventional twin screw extruder.

In a specific embodiment, the thermoplastic resin composition (light diffuser) may have a transmittance of 96% or more, for example, 96 to 98%, of a 1.0 mm thick specimen measured according to ASTM D1003, and a transmittance of a 2.0 mm thick specimen of 92 % Or more, for example 92 to 97%.

In a specific embodiment, the thermoplastic resin composition has an angle of 3 to 20°, for example, 5 to 17°, which is half of the light intensity value at 0° measured using a variable angle photometer for a 1.0 mm thick specimen. In addition, for a 2.0 mm thick specimen, the angle of the luminous intensity value, which is half of the luminous intensity value at 0° measured using a variable angle photometer, may be 10 to 30°, for example, 12 to 26°.

The light diffusion plate according to the present invention is formed from the thermoplastic resin composition. The thermoplastic resin composition may be prepared in the form of pellets, and the prepared pellets may be manufactured into various light diffusion plates (products) through various molding methods such as injection molding, extrusion molding, vacuum molding, and casting molding. Such a molding method is well known by those of ordinary skill in the field to which the present invention belongs. Since the light diffusion plate has excellent stiffness, impact resistance, heat resistance, flame retardancy, and balance of properties thereof, it is useful as an interior/exterior material for electric/electronic products, a diffusion plate for lighting products, and the like.

In a specific embodiment, the light diffusion plate is a light diffusion plate in which a light diffusion agent is dispersed in a polycarbonate resin matrix, and the light diffusion agent may include the polystyrene-polymethylmethacrylate copolymer particles.

In a specific embodiment, the light diffusion plate is 100 parts by weight of the polycarbonate resin matrix; And 0.5 to 3 parts by weight of the light diffusing agent, for example, 1 to 2 parts by weight. Within the above range, light transmittance, light diffusivity, and balance of physical properties of the light diffusion plate may be excellent.

Hereinafter, the present invention will be described in more detail through examples, but these examples are for the purpose of description only and should not be construed as limiting the present invention.

Example

Hereinafter, specifications of each component used in Examples and Comparative Examples are as follows.

(A) Polycarbonate resin

Bisphenol-A-based polycarbonate resin (weight average molecular weight: 23,000 g/mol) was used.

(B) Polystyrene-polymethylmethacrylate copolymer particles

(B1) Polystyrene-polymethylmethacrylate copolymer particles (manufacturer: ASP, product name: MS-5FDB, 50% by weight of polystyrene and 50% by weight of polymethylmethacrylate, average particle diameter: 5.0 μm, coefficient of variation (CV): 35) was used.

(B2) 45% by weight of styrene and 55% by weight of methyl methacrylate were mixed in a 4-neck flask reactor under a nitrogen atmosphere, and then, when the temperature of the flask was 70°C, 4 parts by weight of potassium persulfate were dissolved. 300 mL of an aqueous solution was mixed in the flask and reacted for 6 hours, 20 parts by weight of ethylene glycol di(meth)acrylate (EGDMA) was mixed as a linker for forming a bond between polystyrene, and 5,000 using a high speed agitator (homogeneizer). After homogenizing at rpm for 5 minutes to prepare an emulsion, polymerization was performed for 24 hours, the polymer synthesized by the reaction was filtered, washed with water and an aqueous ethanol solution, and the filtrate was put in a vacuum oven for one day. Polystyrene-polymethylmethacrylate copolymer particles prepared by drying (polystyrene 45% by weight and polymethylmethacrylate 55% by weight, average particle diameter: 5.0 µm, coefficient of variation (CV): 35) were used.

(B3) 55% by weight of styrene and 45% by weight of methyl methacrylate were mixed in a four-neck flask reactor under a nitrogen atmosphere, and then, when the temperature of the flask was 70°C, 4 parts by weight of potassium persulfate were dissolved. After mixing 300 mL of an aqueous solution into the flask and reacting for 6 hours, 25 parts by weight of ethylene glycol di(meth)acrylate (EGDMA) as a linker for forming a bond between polystyrene was mixed, and the same as in (B2) Polystyrene-polymethylmethacrylate copolymer particles prepared by the method (55% by weight of polystyrene and 45% by weight of polymethylmethacrylate, average particle diameter: 5.0 µm, coefficient of variation (CV): 35) were used.

(B4) 40% by weight of styrene and 60% by weight of methyl methacrylate were mixed in a 4-neck flask reactor under a nitrogen atmosphere, and then, when the temperature of the flask was 70°C, 4 parts by weight of potassium persulfate were dissolved. 300 mL of an aqueous solution was mixed in the flask and reacted for 6 hours, 15 parts by weight of ethylene glycol di(meth)acrylate (EGDMA) was mixed as a linker for forming a bond between polystyrene, and then the same as in (B2) Polystyrene-polymethylmethacrylate copolymer particles prepared by the method (polystyrene 40% by weight and polymethylmethacrylate 60% by weight, average particle diameter: 5.0 µm, coefficient of variation (CV): 35) were used.

(B5) After mixing 60% by weight of styrene and 40% by weight of methyl methacrylate in a 4-neck flask reactor under a nitrogen atmosphere, when the temperature of the flask is 70°C, 4 parts by weight of potassium persulfate are dissolved. 300 mL of an aqueous solution was mixed in the flask and reacted for 6 hours, and 30 parts by weight of ethylene glycol di(meth)acrylate (EGDMA) as a linker for forming a bond between polystyrene was mixed, and then the same as in (B2) Polystyrene-polymethylmethacrylate copolymer particles prepared by the method (polystyrene 60% by weight and polymethylmethacrylate 40% by weight, average particle diameter: 5.0 μm, coefficient of variation (CV): 35) were used.

(B6) 50% by weight of styrene and 50% by weight of methyl methacrylate were mixed in a 4-neck flask reactor under a nitrogen atmosphere, and then, when the temperature of the flask was 70°C, 4 parts by weight of potassium persulfate were dissolved. 600 mL of an aqueous solution was mixed in the flask and reacted for 6 hours, 20 parts by weight of ethylene glycol di(meth)acrylate (EGDMA) was mixed as a linker for forming a bond between polystyrene, and 8,000 using a high-speed agitator (homogeneizer). After homogenizing at rpm for 5 minutes to prepare an emulsion, polymerization was performed for 24 hours, the polymer synthesized by the reaction was filtered, washed with water and an aqueous ethanol solution, and the filtrate was put in a vacuum oven for one day Polystyrene-polymethylmethacrylate copolymer particles prepared by drying (polystyrene 50% by weight and polymethyl methacrylate 50% by weight, average particle diameter: 2.0 µm, coefficient of variation (CV): 35) were used.

(B7) 50% by weight of styrene and 50% by weight of methyl methacrylate were mixed in a 4-neck flask reactor under a nitrogen atmosphere, and then, when the temperature of the flask was 70°C, 4 parts by weight of potassium persulfate were dissolved. 250 mL of an aqueous solution was mixed in the flask and reacted for 6 hours, 20 parts by weight of ethylene glycol di(meth)acrylate (EGDMA) was mixed as a linker for forming a bond between polystyrene, and 4,000 using a high speed agitator (homogeneizer). After homogenizing at rpm for 5 minutes to prepare an emulsion, polymerization was performed for 24 hours, the polymer synthesized by the reaction was filtered, washed with water and an aqueous ethanol solution, and the filtrate was put in a vacuum oven for one day. Polystyrene-polymethylmethacrylate copolymer particles prepared by drying (polystyrene 50% by weight and polymethyl methacrylate 50% by weight, average particle diameter: 10.0 μm, coefficient of variation (CV): 35) were used.

(B8) 50% by weight of styrene and 50% by weight of methyl methacrylate were mixed in a 4-neck flask reactor under a nitrogen atmosphere, and then, when the temperature of the flask was 70°C, 4 parts by weight of potassium persulfate were dissolved. 300 mL of an aqueous solution was mixed in the flask and reacted for 6 hours, 20 parts by weight of ethylene glycol di(meth)acrylate (EGDMA) was mixed as a linker for forming a bond between polystyrene, and 6,000 using a high-speed agitator (homogeneizer). After homogenizing at rpm for 10 minutes to prepare an emulsion, polymerization reaction was performed for 24 hours, the polymer synthesized by the reaction was filtered, washed with water and an aqueous ethanol solution, and the filtrate was put in a vacuum oven for one day. Polystyrene-polymethylmethacrylate copolymer particles prepared by drying (polystyrene 50% by weight and polymethyl methacrylate 50% by weight, average particle diameter: 5.0 μm, coefficient of variation (CV): 14) were used.

(B9) After mixing 50% by weight of styrene and 50% by weight of methyl methacrylate in a four-neck flask reactor under a nitrogen atmosphere, when the temperature of the flask is 70°C, 4 parts by weight of potassium persulfate are dissolved. 250 mL of an aqueous solution was mixed in the flask and reacted for 6 hours, 20 parts by weight of ethylene glycol di(meth)acrylate (EGDMA) was mixed as a linker for forming a bond between polystyrene, and 3,000 using a high-speed agitator (homogeneizer). After homogenizing at rpm for 2 minutes to prepare an emulsion, polymerization was carried out for 24 hours, the polymer synthesized by the reaction was filtered, washed with water and an aqueous ethanol solution, and the filtrate was put in a vacuum oven for one day. Polystyrene-polymethylmethacrylate copolymer particles prepared by drying (polystyrene 50% by weight and polymethyl methacrylate 50% by weight, average particle diameter: 5.0 μm, coefficient of variation (CV): 50) were used.

(C) acrylic light diffusing agent

Polymethyl methacrylate particles (manufacturer: ASP, product name: MH-5FD) were used.

Examples 1 to 5 and Comparative Examples 1 to 9

Each of the above constituents was added in an amount as shown in Tables 1 and 2 below, and then extruded at 250 to 280°C to prepare a pellet. Extrusion was performed using a twin-screw extruder with L/D=36 and diameter of 45 mm, and the prepared pellets were dried at 100°C for 4 hours or more, and then injected from a 6 Oz injection machine (molding temperature 260°C, mold temperature: 60°C) Was prepared. The prepared specimens were evaluated for physical properties by the following method, and the results are shown in Tables 1 and 2 below.

How to measure physical properties

(1) Light transmittance evaluation: The transmittance (unit:%) of a 1.0 mm thick specimen and a 2.0 mm thick specimen measured according to ASTM D1003 was measured.

(2) Evaluation of light diffusivity: For a 1.0 mm thick specimen and a 2.0 mm thick specimen, the luminous intensity value that is half of the luminous intensity at 0° measured using a variable angle photometer (manufacturer: NIPPON DENSHOKU, product name: GC 5000L) The angle (unit: °) was measured.

Example Comparative example One 2 3 4 5 One 2 (A) (parts by weight) 100 100 100 100 100 100 100 (B1) (parts by weight) One 1.5 2 - - 0.4 4 (B2) (parts by weight) - - - 1.5 - (B3) (parts by weight) - - - - 1.5 - - Transmittance (1.0 mm) 97.4 97.5 97.1 96.6 96.4 93.2 91.5 Transmittance (2.0 mm) 95.7 93.1 92.4 92.7 92.9 91.5 81.5 Diffusion (1.0 mm) 5 14 17 12 15 0 22 Diffusion (2.0 mm) 12 23 26 26 24 2 37

Comparative example 3 4 5 6 7 8 9 (A) (parts by weight) 100 100 100 100 100 100 100 (B4) (parts by weight) 1.5 - - - - - - (B5) (parts by weight) - 1.5 - - - - - (B6) (parts by weight) - - 1.5 - - - - (B7) (parts by weight) - - - 1.5 - - - (B8) (parts by weight) - - - - 1.5 - - (B9) (parts by weight) - - - - - 1.5 - (C) (parts by weight) - - - - - - 1.5 Transmittance (1.0 mm) 93.0 95.0 93.2 91.2 93.0 91.0 91.2 Transmittance (2.0 mm) 90.0 91.0 89.5 87.0 90.2 90.2 80.0 Diffusion (1.0 mm) 10 8 8 0 3 0 10 Diffusion (2.0 mm) 32 22 12 One 5 0 35

From the above results, it can be seen that the thermoplastic resin composition of the present invention has excellent light transmittance, light diffusivity, and balance of physical properties thereof.

On the other hand, when the content of the polystyrene-polymethylmethacrylate copolymer particles of the present invention is less than the range of the present invention (Comparative Example 1), it can be seen that light diffusivity, etc. are deteriorated, and when the content of the polystyrene-polymethylmethacrylate copolymer particles of the present invention is less than the range of the present invention ( Comparative Example 2), it can be seen that light transmittance, light diffusivity, and the like are deteriorated. Comparison of applying polystyrene-polymethylmethacrylate copolymer particles (B4) in which the content range of polystyrene and polymethylmethacrylate is out of the scope of the present invention instead of the polystyrene-polymethylmethacrylate copolymer particles (B1) of the present invention In the case of Example 3, it can be seen that light transmittance and light diffusivity are deteriorated, and in the case of Comparative Example 4 in which polystyrene-polymethyl methacrylate copolymer particles (B5) are applied, light transmittance and light diffusivity are deteriorated. It can be seen, and in the case of Comparative Example 5 in which the polystyrene-polymethylmethacrylate copolymer particles (B6) having an average particle diameter exceeding the range of the present invention are applied, it can be seen that light transmittance, light diffusivity, etc. are deteriorated. In the case of Comparative Example 6 in which the polystyrene-polymethylmethacrylate copolymer particles (B7) having a particle diameter of less than the range of the present invention were applied, it can be seen that light transmittance, light diffusivity, etc. are deteriorated, and CV exceeds the scope of the present invention. In the case of Comparative Example 7 in which the polystyrene-polymethylmethacrylate copolymer particles (B8) are applied, it can be seen that light transmittance, light diffusivity, etc. are deteriorated, and polystyrene-polymethylmethacrylate having a CV less than the scope of the present invention In the case of Comparative Example 8 in which the copolymer particles (B9) were applied, it can be seen that the light transmittance and the light diffusibility were deteriorated, and instead of the polystyrene-polymethylmethacrylate copolymer particles (B1) of the present invention, polymethylmethacrylic In the case of Comparative Example 9 to which the rate particles (C) were applied, it can be seen that light transmittance, light diffusivity, and the like are deteriorated.

Simple modifications or changes of the present invention can be easily implemented by those of ordinary skill in the art, and all such modifications or changes can be considered to be included in the scope of the present invention.

Claims (9)

100 parts by weight of polycarbonate resin; And
Including 0.5 to 3 parts by weight of polystyrene-polymethyl methacrylate copolymer particles,
The polystyrene-polymethylmethacrylate copolymer particles have a polystyrene content of 41 to 59% by weight, a polymethylmethacrylate content of 41 to 59% by weight, an average particle diameter of 3 to 9 μm, and the following formula 1 A thermoplastic resin composition, characterized in that the coefficient of variation (CV) of the particle diameter is 20 to 40:
[Equation 1]
Coefficient of variation (CV) = [σ / M]
In Equation 1, M is the average particle diameter of the copolymer particles, and σ is the standard deviation of the particle diameter of the copolymer particles.
The thermoplastic resin composition of claim 1, wherein the polycarbonate resin has a weight average molecular weight of 20,000 to 30,000 g/mol.
The thermoplastic resin composition of claim 1, wherein the thermoplastic resin composition has a transmittance of 96% or more of a 1.0 mm thick specimen measured according to ASTM D1003 and a transmittance of 92% or more of a 2.0 mm thick specimen.
The method of claim 1, wherein the thermoplastic resin composition has an angle of 3 to 20°, which is half of the light intensity value at 0° measured using a variable angle photometer, for a 1.0 mm thick specimen, and a 2.0 mm thick specimen On the other hand, a thermoplastic resin composition, characterized in that the angle of the luminous intensity value, which is half of the luminous intensity value at 0° measured using a variable angle photometer, is 10 to 30°.
The light diffusion plate formed from the thermoplastic resin composition according to any one of claims 1 to 4.
It is a light diffuser plate in which a light diffuser is dispersed in a polycarbonate resin matrix,
The light diffusing agent includes polystyrene-polymethylmethacrylate copolymer particles,
The polystyrene-polymethyl methacrylate copolymer particles have an average particle diameter of 3 to 9 µm, and a coefficient of variation (CV) of 20 to 40 of the particle diameter according to Equation 1 below:
[Equation 1]
Coefficient of variation (CV) = [σ / M]
In Equation 1, M is the average particle diameter of the copolymer particles, and σ is the standard deviation of the particle diameter of the copolymer particles.
According to claim 6, The polycarbonate resin matrix 100 parts by weight; And 0.5 to 3 parts by weight of the light diffusing agent.
The light diffusion plate according to claim 6, wherein the light diffusion plate has a transmittance of 96% or more of a 1.0 mm thick specimen measured according to ASTM D1003, and a transmittance of 92% or more of a 2.0 mm thick specimen.
The method of claim 6, wherein the light diffusing plate has an angle of 3 to 20°, which is half of the light intensity value at 0° measured using a variable angle photometer, for a 1.0 mm thick specimen, and a 2.0 mm thick specimen On the other hand, a light diffuser plate, characterized in that the angle of the luminous intensity value, which is half of the luminous intensity value at 0° measured using a variable angle photometer, is 10 to 30°.