Thermoplastic resin composition, and molded article produced therefrom

Abstract

A thermoplastic resin composition of the present invention comprises: a thermal stabilizer including a rubber-modified vinyl-based graft copolymer and a phenol-based thermoplastic resin thermal stabilizer including an aromatic vinyl-based copolymer resin and a phosphorus-based thermal stabilizer; and a zinc oxide which has an average particle size of approximately 0.5 to approximately 3 μm and a specific surface area BET of approximately 1 to approximately 10 m.sup.2/g. The thermoplastic resin composition has excellent low-odor and antibacterial properties.

Claims

1. A thermoplastic resin composition comprising: about 100 parts by weight of a thermoplastic resin comprising about 20 wt % to about 50 wt % of a rubber-modified vinyl graft copolymer and about 50 wt % to about 80 wt % of an aromatic vinyl copolymer; a heat stabilizer comprising about 0.05 to about 2 parts by weight of a phenol-based heat stabilizer and about 0.05 to about 2 parts by weight of a phosphorus-based heat stabilizer; and about 0.3 to about 10 parts by weight of zinc oxide having an average particle size of about 0.5 μm to about 3 μm and a BET specific surface area of about 1 m.sup.2/g to about 10 m.sup.2/g.

2. The thermoplastic resin composition according to claim 1, wherein the rubber-modified vinyl graft copolymer is prepared by graft polymerization of a monomer mixture comprising an aromatic vinyl monomer and a vinyl cyanide monomer to a 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 vinyl cyanide monomer.

4. The thermoplastic resin composition according to claim 1, wherein the phenol-based heat stabilizer comprises octadecyl-3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate and/or 2,2′-ethylidene-bis(4,6-di-tert-butylphenol).

5. The thermoplastic resin composition according to claim 1, wherein the phosphorus-based heat stabilizer comprises distearyl pentaerythritol diphosphite and/or diphenyl isooctyl phosphite.

6. The thermoplastic resin composition according to claim 1, wherein the zinc oxide has a peak intensity ratio (B/A) of about 0.01 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 zinc oxide has a peak position (20) 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: $\begin{array}{cc}\mathrm{Crystallite}\mathrm{size}\left(D\right)=\frac{K\lambda }{\beta \cos \theta }& \left[\mathrm{Equation}1\right]\end{array}$ 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.

8. The thermoplastic resin composition according to claim 1, wherein the phenol-based heat stabilizer and the phosphorus-based heat stabilizer are present in a weight ratio (phenol-based heat stabilizer:phosphorus-based heat stabilizer) of about 1:1 to about 1:2.

9. The thermoplastic resin composition according to claim 1, wherein the heat stabilizer and the zinc oxide are present in a weight ratio (heat stabilizer:zinc oxide) of about 1:0.75 to about 1:15.

10. The thermoplastic resin composition according to claim 1, wherein the thermoplastic resin composition has a total volatile organic compound detection area of about 600 to about 2,000 area/g, as detected by HS-SPME GC/MS (head space solid-phase microextraction coupled to gas chromatography/mass spectrometry) after collecting volatile organic compounds at 120° C. for 300 min.

11. The thermoplastic resin composition according to claim 1, wherein the thermoplastic resin composition has a residual volatile matter content of about 800 ppm to about 2,000 ppm, as measured at 250° C. by GC/MS (gas chromatography/mass spectrometry).

12. The thermoplastic resin composition according to claim 1, wherein the thermoplastic resin composition has an antibacterial activity of about 2 to about 7 against each of Staphylococcus aureus and Escherichia coli, as measured on 5 cm×5 cm specimens inoculated with Staphylococcus aureus and Escherichia coli, respectively, in accordance with JIS Z 2801.

13. The thermoplastic resin composition according to claim 1, wherein the thermoplastic resin composition is a material for 3D printing.

14. A molded article formed of the thermoplastic resin composition according to claim 1.

15. A thermoplastic resin composition comprising: a thermoplastic resin comprising a rubber-modified vinyl graft copolymer and an aromatic vinyl copolymer; a heat stabilizer comprising a phenol-based heat stabilizer and a phosphorus-based heat stabilizer; and zinc oxide having an average particle size of about 0.5 μm to about 3 μm and a BET specific surface area of about 1 m.sup.2/g to about 10 m.sup.2/g, wherein the thermoplastic resin composition has a total volatile organic compound detection area of about 600 to about 2,000 area/g, as detected by HS-SPME GC/MS (head space solid-phase microextraction coupled to gas chromatography/mass spectrometry) after collecting volatile organic compounds at 120° C. for 300 min.

Description

MODE FOR INVENTION

(1) Next, the present invention will be described in more detail with reference to some examples. It should be understood that these examples are provided for illustration only and are not to be construed in any way as limiting the invention.

EXAMPLE

(2) Details of components used in Examples and Comparative Examples are as follows.

(3) (A) Thermoplastic resin

(4) (A1-1) Rubber-modified aromatic vinyl graft copolymer

(5) A g-ABS copolymer obtained by grafting 55 wt % of a mixture comprising styrene and acrylonitrile (weight ratio: 75/25) to 45 wt % of butadiene rubber having a Z-average particle diameter of 310 nm was used.

(6) (A1-2) Rubber-modified aromatic vinyl graft copolymer

(7) A g-ASA copolymer obtained by grafting 55 wt % of a mixture comprising styrene and acrylonitrile (weight ratio: 75/25) to 45 wt % of butyl acrylate rubber having a Z-average particle diameter of 310 nm was used.

(8) (A2) Aromatic vinyl copolymer resin

(9) A SAN resin (weight average molecular weight: 130,000 g/mol) obtained through polymerization of 71 wt % of styrene and 29 wt % of acrylonitrile was used.

(10) (B) Heat stabilizer

(11) (B1) Octadecyl-3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate was used as a phenol-based heat stabilizer.

(12) (B2) Distearyl pentaerythritol diphosphite was used as a phosphorus-based heat stabilizer.

(13) (C) Zinc oxide

(14) (C1) Zinc oxide having an average particle diameter, a BET surface area, a purity, and a peak intensity ratio (B/A) of peak B in the wavelength range of 450 nm to 600 nm to peak A in the wavelength range of 370 nm to 390 nm in photoluminescence measurement, and a crystallite size as listed in Table 1 was used.

(15) (C2) Zinc oxide (Product Name: RZ-950, Ristechbiz Co., Ltd.) having an average particle diameter, a BET surface area, a purity, and a peak intensity ratio (B/A) of peak B in the wavelength range of 450 nm to 600 nm to peak A in the wavelength range of 370 nm to 390 nm in photoluminescence measurement, and a crystallite size as listed in Table 1 was used.

(16) TABLE-US-00001 TABLE 1 (C1) (C2) Average particle diameter (μm) 1.0 1.1 BET surface area (m.sup.2/g) 6 15 Purity (%) 99.2 97 PL peak intensity ratio (B/A) 0.05 9.8 Crystallite size (Å) 1,229 503

(17) Property Measurement

(18) (1) Average particle diameter (unit: μm): Average particle diameter (volume average) was measured using a particle size analyzer (Laser Diffraction Particle size analyzer LS I3 320, Beckman Coulter Co., Ltd.).

(19) (2) BET surface area (unit: m.sup.2/g): BET surface area was measured by a nitrogen gas adsorption method using a BET analyzer (Surface Area and Porosity Analyzer ASAP 2020, Micromeritics Co., Ltd.).

(20) (3) Purity (unit: %): Purity was measured by thermo-gravimetric analysis (TGA) based on the weight of the remaining material at 800° C.

(21) (4) PL peak intensity ratio (B/A): Spectrum emitted upon irradiation of a specimen using a He—Cd laser (KIMMON, 30 mW) at a wavelength of 325 nm at room temperature was detected by a CCD detector in a photoluminescence measurement method, in which the CCD detector was maintained at −70° C. A peak intensity ratio (B/A) of peak B in the wavelength range of 450 nm to 600 nm to peak A in the wavelength range of 370 nm to 390 nm was measured. Here, an injection molded specimen was irradiated with laser beams without separate treatment upon PL analysis and zinc oxide powder was compressed in a pelletizer having a diameter of 6 mm to prepare a flat specimen.

(22) (5) Crystallite size (unit: A): Crystallite size was measured using a high-resolution X-ray diffractometer (PRO-MRD, X'pert Co., Ltd.) at a peak position degree (20) in the range of 35° to 37° and calculated by Scherrer's Equation (Equation 1) with reference to a measured FWHM value (full width at half maximum of a diffraction peak). Here, both a specimen in powder form and an injection molded specimen could be used, and for more accurate analysis, the injection molded specimen was subjected to heat treatment at 600° C. in air for 2 hours to remove a polymer resin before XRD analysis.

(23) $\begin{array}{cc}\mathrm{Crystallite}\mathrm{size}\left(D\right)=\frac{K\lambda }{\beta \cos \theta }& \left[\mathrm{Equation}2\right]\end{array}$

(24) where K is a shape factor, λ, is an X-ray wavelength, β is an FWHM value (degree), and θ is a peak position degree.

Examples 1 to 5 and Comparative Examples 1 to 3

(25) The above components were weighed in amounts as listed in Table 2 and subjected to extrusion at 230° C., thereby preparing pellets. Extrusion was performed using a twin-screw extruder (L/D=36, Φ: 45 mm). The prepared pellets were dried at 80° C. for 2 hours or more and injection-molded in a 6 oz. injection molding machine (molding temperature: 230° C., mold temperature: 60° C.), thereby preparing specimens. The prepared specimens were evaluated as to the following properties by the following method, and results are shown in Table 2.

(26) Property Evaluation

(27) (1) Low-odor evaluation (Total volatile organic compound (TVOC), unit: Area/g): A detection area of volatile organic compounds collected at 120° C. for 300 min was measured at 120° C. for 5 hours by HS-SPME GC/MS (headspace solid-phase microextraction coupled to gas chromatography/mass spectrometry). Measurement conditions and a pretreatment method were as follows.

(28) Measurement Condition

(29) TABLE-US-00002 Parameters Conditions HSS Headspace Sampler Agilent Technologies G1888 Method Required conditions (Temperature: 120° C., Collecting time 300 min) GC Column Carbowax 20M (ID 0.32 mm, L 25 m, film thickness 0.30 μm) Moving phase He Pressure 7.8 psi Flow 2.0 ml/min (Average velocity = 32 cm/sec) Split Split ratio = 5:1 Method 40° C. 3 min .fwdarw. 200° C. 4 min (R = 12° C./min) Detector FID

(30) Pretreatment Method

(31) 1) A sample was placed in an HSS vial (Powder 20 mg, Pellet 2 g).

(32) 2) Headspace sampler conditions were set as above.

(33) (2) Low-odor evaluation (residual volatile matter (RTVM) content, unit: ppm): Residual volatile matter content was measured at 250° C. by GC/MS (gas chromatography/mass spectrometry). Measurement conditions and a pretreatment method were as follows.

(34) Measurement Condition

(35) TABLE-US-00003 Parameter Conditions Column INNOWAX (length 30 M, ID 0.53 mm, film thickness 0.88 μm) Temp. Prog. 40° C. (4 min) .fwdarw. 250° C. (4 min) (R = 20° C./min) Flow rate 10 mL/min (Head-pressure 6.57 Pa) Split ratio 5:1 Detector FID Injection Vol. 1 μl Injector temp. 150° C.

(36) Pretreatment Method

(37) 1) 0.2 to 0.3 g of a sample was placed in a 20 mL vial.

(38) 2) 9 mL NMP was added to the vial and dissolved therein using a shaker for 10 hours or more.

(39) 3) 1 mL of an internal standard solution was added thereto, followed by stirring. The resulting material was filtered through a 0.45 μm filter.

(40) (3) Antibacterial activity: Antibacterial activity was measured on a 5 cm×5 cm specimen obtained by inoculation with each of Staphylococcus aureus and Escherichia coli, followed by culturing under conditions of 35° C. and 90% RH for 24 hours, in accordance with JIS Z 2801.

(41) TABLE-US-00004 TABLE 2 Example Comparative Example 1 2 3 4 5 1 2 3 (A) (A1-1) 30 30 30 — — 30 30 — (wt %) (A1-2) — — — 40 40 — — 40 (A2) 70 70 70 60 60 70 70 60 (B) (B1) 0.2 1.0 0.1 0.2 0.2 — 0.5 0.2 (parts by (B2) 0.3 1.0 0.1 0.3 0.3 0.5 — 0.3 weight) (C) (C1) 1.5 1.5 1.5 5.0 0.5 1.5 1.5 — (parts by (C2) — — — — — — — 1.5 weight) TVOC detection area 700 900 1,000 1,200 1,300 9,000 10,000 17,000 (area/g) RTVM content (ppm) 1,000 1,100 1,000 1,500 1,400 2,000 1,800 2,200 Antibacterial activity 4.6 4.6 4.6 4.6 4.6 4.6 4.6 2.0 (Escherichia coli) Antibacterial activity 6.3 6.3 6.3 6.3 6.3 6.3 6.3 2.5 (Staphylococcus aureus) *Parts by weight: (A) Parts by weight relative to 100 parts by weight

(42) From the results, it can be seen that the thermoplastic resin composition according to the present invention has good properties in terms of low-odor and antibacterial properties.

(43) Conversely, the composition (Comparative Example 1) prepared without using the phenol-based heat stabilizer (B1) and the composition (Comparative Example 2) prepared without using the phosphorus-based heat stabilizer (B2) suffered from significant deterioration in low-odor, thereby generating severe odor upon formation of pellets. In addition, the composition (Comparative Example 3) prepared using zinc oxide (C2) instead of zinc oxide (C1) of the present invention suffered from deterioration in low-odor and antibacterial properties.

(44) It should be understood that various modifications, changes, alterations, and equivalent embodiments can be made by those skilled in the art without departing from the spirit and scope of the present invention.