Thermoplastic resin composition and molded article manufactured therefrom
A thermoplastic resin composition of the present invention is characterized by comprising: a thermoplastic resin containing an acrylate-based rubber-modified vinyl-based graft copolymer and an aromatic vinyl-based copolymer resin; an ultraviolet stabilizer containing a hindered amine light stabilizer (HALS)-based ultraviolet stabilizer and a benzotriazole-based ultraviolet stabilizer; and zinc oxide having an average particle size of about 0.5 to about 3 μm and a specific surface area BET of about 1 to about 10 m 2 /g. The thermoplastic resin composition has excellent weather resistance and antibacterial properties.
1. A thermoplastic resin composition comprising:
about 100 parts by weight of a thermoplastic resin comprising about 20 wt % to about 50 wt % of an acrylate-based rubber-modified vinyl graft copolymer and about 50 wt % to about 80 wt % of an aromatic vinyl copolymer resin;
an ultraviolet (UV) stabilizer comprising about 0.05 to about 2 parts by weight of an HALS (hindered amine light stabilizer)-based UV stabilizer and about 0.05 to about 2 parts by weight of a benzotriazole-based UV stabilizer; and
about 0.1 to about 5 parts by weight of zinc oxide having an average particle diameter of about 0.5 μm to about 3 μm, a BET specific surface area of about 1 m 2 /g to about 10 m 2 /g, a peak position (2θ) in the range of 35° to 37° and a crystallite size of about 1,000 Å to about 2,000 Å in X-ray diffraction (XRD) analysis as calculated by Equation 1:
Crystallite
size
(
D
)
=
K
λ
β
cos
θ
[
Equation
1
]
where K is a shape factor, λ is an X-ray wavelength, β is an FWHM value (degree) of an X-ray diffraction peak, and θ is a peak position degree.
2. The thermoplastic resin composition according to claim 1 , wherein the acrylate-based rubber-modified vinyl graft copolymer is prepared by graft copolymerization of a monomer mixture comprising an aromatic vinyl monomer and a vinyl cyanide monomer to an acrylate-based rubber polymer.
3. The thermoplastic resin composition according to claim 1 , wherein the aromatic vinyl copolymer resin is a polymer of an aromatic vinyl monomer and a monomer copolymerizable with the aromatic vinyl monomer.
4. The thermoplastic resin composition according to claim 1 , wherein the HALS-based UV stabilizer comprises bis(2,2,6,6-tetramethyl-4-piperidyl)sebacate and/or bis(2,2,6,6-tetramethyl-2-piperidyl)sebacate.
5. The thermoplastic resin composition according to claim 1 , wherein the benzotriazole-based UV stabilizer comprises 2-(2H-benzotriazole-2-yl)-4-(1,2,3,3-tetramethylbutyl)phenol, 2-(2-hydroxy-5-methyl-phenyl)benzotriazole, 2-(2H-benzotriazole-2-yl)-4-(1,1,3,3-tetramethylbutyl)phenol, and/or 2-(5-chloro-2H-benzotriazole-2-yl)-4,6-bis(1,1-dimethylethyl)phenol.
6. The thermoplastic resin composition according to claim 1 , wherein the zinc oxide has a peak intensity ratio (B/A) of about 0 to about 1, where A indicates a peak in the wavelength range of 370 nm to 390 nm and B indicates a peak in the wavelength range of 450 nm to 600 nm in photoluminescence measurement.
7. The thermoplastic resin composition according to claim 1 , wherein the HALS-based UV stabilizer and the benzotriazole-based UV stabilizer are present in a weight ratio (HALS-based UV stabilizer:benzotriazole-based UV stabilizer) of about 1:0.5 to about 1:1.1.
8. The thermoplastic resin composition according to claim 1 , wherein the UV stabilizer and the zinc oxide are present in a weight ratio (UV stabilizer:zinc oxide) of about 1:0.5 to about 1:10.
9. The thermoplastic resin composition according to claim 1 , wherein the thermoplastic resin composition has a color variation (ΔE) of about 0.5 to about 2.5, as calculated according to Equation 2 based on initial color values (L 0 *, a 0 *, b 0 *) measured on an injection-molded specimen having a size of 50 mm×90 mm×3 mm using a colorimeter and color values (L 1 *, a 1 *, b 1 *) of the specimen measured using the colorimeter after testing for 3,000 hours in accordance with ASTM D4459:
Color variation (Δ E )=√{square root over ((Δ L *) 2 +(Δ a *) 2 +(Δ b *) 2 )} [Equation 2]
where ΔL* is a difference (L 1 *−L 0 *) between L* values before and after testing, Δa* is a difference (a 1 *−a 0 *) between a* values before and after testing, and Δb* is a difference (b 1 *−b 0 *) between b* values before and after testing.
10. The thermoplastic resin composition according to claim 1 , wherein the thermoplastic resin composition has an antibacterial activity of about 2 to about 7 against Staphylococcus aureus and an antibacterial activity of about 2 to about 7 against Escherichia coli , as measured on 5 cm×5 cm specimens after inoculation with Staphylococcus aureus and Escherichia coli , respectively, and culturing under conditions of 35° C. and 90% RH for 24 hours in accordance with JIS Z 2801.
11. A molded article formed of the thermoplastic resin composition according to claim 1 .
12. The thermoplastic resin composition according to claim 1 , wherein the zinc oxide has a peak intensity ratio (B/A) of about 0.1 to about 1, where A indicates a peak in the wavelength range of 370 nm to 390 nm and B indicates a peak in the wavelength range of 450 nm to 600 nm in photoluminescence measurement.