Thermoplastic Resin Composition and Molded Article Manufactured Therefrom

Abstract

A thermoplastic resin composition of the present invention is characterized by comprising: about 100 parts by weight of a thermoplastic resin containing a rubber-modified vinyl-based graft copolymer and an aromatic vinyl-based copolymer resin; about 10 to about 30 parts by weight of an antistatic agent; and about 0.01 to about 2 parts by weight of zinc oxide, wherein the antistatic agent comprises at least one of a polyether ester amide block copolymer, a polyalkylene glycol, and a polyamide. The thermoplastic resin composition is excellent in antibacterial properties, antistatic properties, impact resistance, and the like.

Claims

1. A thermoplastic resin composition comprising: about 100 parts by weight of a thermoplastic resin comprising a rubber-modified vinyl graft copolymer and an aromatic vinyl copolymer resin; about 10 to about 30 parts by weight of an antistatic agent; and about 0.01 to about 2 parts by weight of zinc oxide, wherein the antistatic agent comprises a polyetheresteramide block copolymer, a polyalkylene glycol, and/or a polyamide.

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 monomer copolymerizable with the aromatic vinyl monomer.

4. The thermoplastic resin composition according to claim 1, wherein the rubber-modified vinyl graft copolymer is present in an amount of about 20 wt % to about 50 wt % and the aromatic vinyl copolymer resin is present in an amount of about 50 wt % to about 80 wt %, based on 100 wt % of the thermoplastic resin.

5. The thermoplastic resin composition according to claim 1, wherein the zinc oxide has an average particle diameter of about 0.2 m to about 3 m and a BET specific surface area of about 1 m.sup.2/g to about 10 m.sup.2/g.

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 zinc oxide has a peak position (20) in the range of 35 to 37 and a crystallite size of about 1,000 A to about 2,000 , in X-ray diffraction (XRD) analysis, as calculated by Equation 1: $\begin{array}{cc}\mathrm{Crystallite}.Math..Math.\mathrm{size}.Math..Math.\left(D\right)=\frac{K.Math..Math.}{.Math..Math.\cos .Math..Math.}& \left[\mathrm{Equation}.Math..Math.1\right]\end{array}$ where K is a shape factor, is an X-ray wavelength, is an FWHM value (degree) of an X-ray diffraction peak, and is a peak position degree.

8. 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 6.5 against Escherichia coli, as measured on 5 cm5 cm specimens inoculated with Staphylococcus aureus and Escherichia coli, respectively, in accordance with JIS Z 2801.

9. The thermoplastic resin composition according to claim 1, wherein the thermoplastic resin composition has a surface resistance of about 110.sup.6.Math.cm to about 110.sup.10 .Math.cm, as measured in accordance with ASTM D257.

10. The thermoplastic resin composition according to claim 1, wherein the thermoplastic resin composition has an Izod impact strength of about 15 kgf.Math.cm/cm to about 25 kgf.Math.cm/cm, as measured on a thick specimen in accordance with ASTM D256.

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

Description

EXAMPLE

[0070] Details of components used in Examples and Comparative Examples are as follows.

[0071] (A) Thermoplastic resin

[0072] (A1) Rubber-modified aromatic vinyl graft copolymer

[0073] 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.

[0074] (A2) Aromatic vinyl copolymer resin

[0075] (A2-1) 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.

[0076] (A2-2) A methyl methacrylate-styrene-acrylonitrile copolymer (MSAN, weight average molecular weight: 90,000 g/mol) prepared by polymerizing 74 wt % of methyl methacrylate, 22 wt % of styrene and 4 wt % of acrylonitrile was used.

[0077] (B) Antistatic agent

[0078] (B1) An antistatic agent (Product Name: PELECTRON AS, Manufacturer: Sanyo Co., Ltd.) comprising a polyetheresteramide block copolymer was used.

[0079] (B2) Ultramide 8270HS (BASF) was used.

[0080] (C) Zinc oxide

[0081] Zinc oxide having an average particle diameter of 1.2 m, a BET surface area of 5.5 m.sup.2/g, a purity of 99.9%, a peak intensity ratio (B/A) of 0.28, 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, and a crystallite size of 1,750 was used.

[0082] (D) Titanium oxide (Product Name: WH-01, Manufacturer: Kemira Specialty Corp.) was used.

[0083] Property Measurement

[0084] (1) Average particle diameter (unit: m): Average particle diameter was measured using a particle size analyzer (Laser Diffraction Particle size analyzer LS I3 320, Beckman Coulter Co., Ltd.).

[0085] (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.).

[0086] (3) Purity (unit: %): Purity was measured by thermo-gravimetric analysis (TGA) based on the weight of the remaining material at 800 C.

[0087] (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.

[0088] (5) Crystallite size (unit: ): Crystallite size was measured using a high-resolution X-ray diffractometer (PRO-MRD, X'pert Co., Ltd.) at a peak position degree (2) 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.

[00003]$\begin{array}{cc}\mathrm{Crystallite}.Math..Math.\mathrm{size}.Math..Math.\left(D\right)=\frac{K.Math..Math.}{.Math..Math.\cos .Math..Math.},& \left[\mathrm{Equation}.Math..Math.2\right]\end{array}$

[0089] where K is a shape factor, is an X-ray wavelength, is an FWHM value (degree), and is a peak position degree.

Examples 1 to 5 and Comparative Examples 1 to 6

[0090] The above components were weighed in amounts as listed in Tables 1 and 2, and subjected to extrusion at 230 C., thereby preparing pellets. Extrusion was performed using a twin-screw extruder (L/D=, 1:45 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 Tables 1 and 2.

[0091] Property Evaluation

[0092] (1) Antibacterial activity: Antibacterial activity was measured on 5 cm5 cm specimens obtained by inoculation with Staphylococcus aureus and Escherichia coli, respectively, followed by culturing under conditions of 35 C. and 90% RH for 24 hours, in accordance with JIS Z 2801.

[0093] (2) Surface resistance (unit: .Math.cm): Surface resistance was measured using a surface resistance tester (Model: Hiresta-UP(MCP-HT450), Manufacturer: Mitsubishi Chemical Co., Ltd.) in accordance with ASTM D257.

[0094] (3) Impact resistance (kgf.Math.cm/cm): Izod impact strength was measured on a thick specimen in accordance with ASTM D256.

[0095] (4) Transparency (haze) (unit: %): Transparency (haze) was measured on a 2.5 mm thick specimen using a haze meter NDH 2000 (Nippon Denshoku Co., Ltd.) in accordance with ASTM D1003.

TABLE-US-00001 TABLE 1 Example 1 2 3 4 5 (A) (A1) 29 29 29 29 29 (wt %) (A2-1) 60 60 60 60 60 (A2-2) 11 11 11 11 11 (B) (B1) 10 20 30 20 20 (parts by (B2) weight) (C) (parts by weight) 0.05 0.05 0.05 0.01 0.2 (D) (parts by weight) Antibacterial activity 4.1 6.4 6.1 4.1 6.3 (Escherichia coli) Antibacterial activity 3.3 4 4 2.3 4 (Staphylococcus aureus) Surface resistance 4.8 10.sup.8 2.4 10.sup.9 4 10.sup.8 2.3 10.sup.9 2.6 10.sup.9 ( .Math. cm) Notched Izod impact 18.1 21.3 15.7 19.9 18.9 strength (kgf .Math. cm/cm) Transparency (Haze) 9.8 14.8 23.1 12.1 31.7 *parts by weight: (A) parts by weight relative to 100 parts by weight

TABLE-US-00002 TABLE 2 Comparative Example 1 2 3 4 5 6 (A) (A1) 29 29 29 29 29 29 (wt %) (A2-1) 60 60 60 60 60 60 (A2-2) 11 11 11 11 11 11 (B) (B1) 5 35 20 20 20 (parts by (B2) 20 weight) (C) (parts by weight) 0.05 0.05 0.005 4 0.05 (D) (parts by weight) 0.05 Antibacterial activity 2.1 6.1 1.1 6.8 1.1 0.6 (Escherichia coli) Antibacterial activity 0.3 4 0.3 4 0.2 0.2 (Staphylococcus aureus) Surface resistance 4.8 10.sup.11 4.2 10.sup.8 2.1 10.sup.9 2.6 10.sup.9 4.8 10.sup.13 2.4 10.sup.9 ( .Math. cm) or more Notched Izod impact 17.1 12.1 20.1 19.5 17.2 19.6 strength (kgf .Math. cm/cm) Transparency (Haze) 8.7 28.6 11.9 50.7 30.2 10.2 *Parts by weight: (A) Parts by weight relative to 100 parts by weight

[0096] From the result, it can be seen that the thermoplastic resin composition according to the present invention has good properties in terms of antibacterial properties, antistatic properties, impact resistance, and the like.

[0097] Conversely, it could be seen that the composition of Comparative Example 1 prepared using a small amount of the antistatic agent suffered from deterioration in antistatic properties, had surface resistance exceed a measurable range, and suffered from significant deterioration in antibacterial properties (S. aureus); the composition of Comparative Example 2 prepared using an excess of the antistatic agent suffered from deterioration in impact resistance; the composition of Comparative Example 3 prepared using a small amount of zinc oxide suffered from significant deterioration in antibacterial properties; and the composition of Comparative Example 4 prepared using an excess of zinc oxide was substantially opaque. In addition, it could be seen that the composition of Comparative Example 5 prepared using the antistatic agent (B2) suffered from deterioration in antistatic properties, antibacterial properties, and the like, and the composition of Comparative Example 6 prepared using titanium oxide as the antimicrobial agent suffered from significant deterioration in antibacterial properties.

[0098] 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.