Polycarbonate-based resin composition and molded article thereof

Abstract

The present invention relates to a polycarbonate-based resin composition and a molded article thereof, and more specifically, to a polycarbonate-based resin composition exhibiting improved impact strength (impact resistance) and chemical resistance while including a glass fiber in a relatively small content, and a molded article formed therefrom.

Claims

1. A polycarbonate-based resin composition comprising: a copolycarbonate resin including an aromatic polycarbonate-based first repeating unit, and an aromatic polycarbonate-based second repeating unit having one or more siloxane bonds, a glass fiber, and an impact-reinforcing agent including a rubber-modified vinyl-based graft copolymer, wherein the first repeating unit includes a repeating unit represented by Chemical Formula 1 below, and; the second repeating unit includes at least one repeating unit selected from the group consisting of Chemical Formula 3 below, and wherein the glass fiber has a rectangular, circular or elliptical cross section in a direction perpendicular to a longitudinal direction, and has an aspect ratio according to Equation 1 below of 50 to 500:
Aspect ratio()=L/D[Equation 1] in Equation 1, L is a length of the glass fiber, D is a length of the longest side of the rectangular cross section, a length of a diameter of the circular cross section, or a length of the longest diameter of the elliptical cross section, ##STR00020## in Chemical Formula 1, R.sup.1 to R.sup.4 are each independently hydrogen, C.sub.1-10 alkyl, C.sub.1-10 alkoxy, or halogen, and Z is C.sub.1-10 alkylene unsubstituted or substituted with phenyl, C.sub.3-15 cycloalkylene unsubstituted or substituted with C.sub.1-10 alkyl, O, S, SO, SO.sub.2, or CO; ##STR00021## in Chemical Formula 3, X.sup.2 is each independently C.sub.1-10 alkylene, Y.sup.1 is each independently hydrogen, C.sub.1-6 alkyl, halogen, hydroxy, C.sub.1-6 alkoxy or C.sub.6-20 aryl, R.sup.6 is each independently hydrogen; C.sub.1-15 alkyl unsubstituted or substituted with oxiranyl, oxiranyl-substituted C.sub.1-10 alkoxy, or C.sub.6-20 aryl; halogen; C.sub.1-10 alkoxy; allyl; C.sub.1-10 haloalkyl; or C.sub.6-20 aryl, and n2 is an integer of 10 to 200.

2. The polycarbonate-based resin composition of claim 1, further comprising: a polycarbonate resin including the aromatic polycarbonate-based first repeating unit represented by Chemical Formula 1.

3. The polycarbonate-based resin composition of claim 1, wherein: the second repeating unit further includes at least one repeating unit selected from the group consisting of Chemical Formula 2 below: ##STR00022## in Chemical Formula 2, X.sup.1 is each independently C.sub.1-10 alkylene, R.sup.5 is each independently hydrogen; C.sub.1-15 alkyl unsubstituted or substituted with oxiranyl, oxiranyl-substituted C.sub.1-10 alkoxy, or C.sub.6-20 aryl; halogen; C.sub.1-10 alkoxy; allyl; C.sub.1-10 haloalkyl; or C.sub.6-20 aryl, and n1 is an integer of 10 to 200.

4. The polycarbonate-based resin composition of claim 1, wherein: the repeating unit represented by Chemical Formula 1 is represented by Chemical Formula 1-1 below: ##STR00023##

5. The polycarbonate-based resin composition of claim 1, wherein: the repeating unit represented by Chemical Formula 3 is represented by Chemical Formula 3-1 below: ##STR00024## in Chemical Formula 3-1, R.sup.6 and n2 are each the same as defined in Chemical Formula 3 above.

6. The polycarbonate-based resin composition of claim 3, wherein: the repeating unit represented by Chemical Formula 2 is represented by Chemical Formula 2-1 below: ##STR00025## in Chemical Formula 2-1, R.sup.5 and n1 are each the same as defined in Chemical Formula 2 above.

7. The polycarbonate-based resin composition of claim 1, wherein: the copolycarbonate resin includes 90 to 99.999 wt % of the first repeating unit and 0.001 to 10 wt % of the second repeating unit.

8. The polycarbonate-based resin composition of claim 2, wherein: the polycarbonate resin has a melt index (MI) of 5 g/10 min to 25 g/10 min at a temperature of 300 C. and under a load of 1.2 kg.

9. The polycarbonate-based resin composition of claim 2, wherein: the polycarbonate resin and the copolycarbonate resin each have a weight average molecular weight of 1,000 to 100,000 g/mol.

10. The polycarbonate-based resin composition of claim 1, wherein: the glass fiber has the length (L) of 2 to 5 mm, and the length (D) of 5 to 40 m.

11. The polycarbonate-based resin composition of claim 1, wherein: the glass fiber is surface-coated with a silane-based compound.

12. The polycarbonate-based resin composition of claim 1, wherein: the rubber-modified vinyl-based graft copolymer is a graft copolymer having a core-shell structure in which a vinyl-based unsaturated monomer is grafted to a core structure to form a shell, the core structure including at least one rubber selected from the group consisting of diene-based rubber, acrylate-based rubber, and silicone-based rubber.

13. The polycarbonate-based resin composition of claim 2, wherein: the polycarbonate-based resin composition includes: 30 to 93 wt % of the copolycarbonate resin, 0 to 65 wt % of the polycarbonate resin, 1 to 40 wt % of the glass fiber, and 1 to 20 wt % of the impact-reinforcing agent.

14. The polycarbonate-based resin composition of claim 1, further comprising: an epoxy silane-based additive.

15. The polycarbonate-based resin composition of claim 14, wherein: the epoxy silane-based additive is included in a content of 0.1 to 3 wt % based on the total resin composition.

16. A molded article comprising the polycarbonate-based resin composition of claim 1.

Description

MODE FOR INVENTION

(1) Hereinafter, preferable Examples of the present invention will be provided for better understanding of the present invention. However, the following Examples are provided only for illustration of the present invention, and should not be construed as limiting the present invention by the examples.

Preparation Example 1

(2) Preparation of Polyorganosiloxane (AP-PDMS, n=34)

(3) ##STR00018##

(4) After 47.6 g (160 mmol) of octamethylcyclotetrasiloxane and 2.4 g (11 mmol) of tetramethyldisiloxane were mixed with each other, the mixture was placed in a 3L flask with 1 part by weight of acidic white clay (DC-A3) based on 100 parts by weight of octamethylcyclotetrasiloxane, and reacted at 60 for 4 hours. After the reaction was terminated, the mixture was diluted with ethylacetate and quickly filtered using a celite. The repeating unit (n1) of the unmodified polyorganosiloxane obtained as described above was 34 when confirmed through .sup.1H NMR.

(5) 4.81 g (35.9 mmol) of 2-allylphenol and 0.01 g (50 ppm) of Karstedt's platinum catalyst were added to the obtained terminal-unmodified polyorganosiloxane and reacted at 90 C. for 3 hours. After the reaction was terminated, the unreacted siloxane was removed by evaporation under condition of 120 C. and 1 torr. The terminal-modified polyorganosiloxane obtained as described above was designated as AP-PDMS (n1=34). AP-PDMS was pale yellow oil, the repeating unit (n1) was 34 when confirmed through .sup.1H NMR using Varian 500 MHz, and further purification was not required.

Preparation Example 2

(6) Preparation of polyorganosiloxane (MBHB-PDMS, n2=58)

(7) ##STR00019##

(8) After 47.60 g (160 mmol) of octamethylcyclotetrasiloxane and 1.5 g (11 mmol) of tetramethyldisiloxane were mixed with each other, the mixture was placed in a 3L flask with 1 part by weight of acidic white clay (DC-A3) based on 100 parts by weight of octamethylcyclotetrasiloxane, and reacted at 60 C. for 4 hours. After the reaction was terminated, the reaction product was diluted with ethylacetate and quickly filtered using a celite. The repeating unit (n2) of the terminal-unmodified polyorganosiloxane obtained as described above was 58 when confirmed through .sup.1H NMR.

(9) 6.13 g (29.7 mmol) of 3-methylbut-3-enyl 4-hydroxybenzoate and 0.01 g (50 ppm) of Karstedt's platinum catalyst were added to the obtained terminal-unmodified polyorganosiloxane and reacted at 90 C. for 3 hours. After the reaction was terminated, the unreacted siloxane was removed by evaporation under condition of 120 C. and 1 torr. The terminal-modified polyorganosiloxane obtained as described above was designated as MBHB-PDMS (n2=58). MBHB-PDMS was pale yellow oil, the repeating unit (n2) was 58 when confirmed through .sup.1H NMR using Varian 500 MHz, and further purification was not required.

Preparation Example 3

(10) Preparation of Copolycarbonate Resin:

(11) 1784 g of water, 385 g of NaOH and 232 g of bisphenol A (BPA) were added to a polymerization reactor, and dissolved with mixing under N.sub.2 atmosphere. To the above-prepared mixture, 4.3 g of para-tert butylphenol (PTBP) and a mixed solution of 4.72 g of AP-PDMS (n1=34) prepared by Preparation Example 1 and 0.52 g of MBHB-PDMS (n2=58) prepared by Preparation Example 2 dissolved in methylene chloride (MC) were added. Subsequently, 128 g of triphosgene (TPG) was dissolved in MC and the dissolved TPG solution was added to the mixture and reacted for 1 hour while maintaining pH at 11 or more. After 10 minutes, 46 g of triethylamine (TEA) was added thereto to perform a coupling reaction. After a total reaction time of 1 hour and 20 minutes, TEA was removed by lowering the pH to 4, and then the produced polymer was washed three times with distilled water so that pH was adjusted to neutral pH of 6 to 7. The obtained polymer was re-precipitated in a mixed solution of methanol and hexane, and dried at 120 C. to finally obtain a copolycarbonate resin (Mw=30,500).

Examples and Comparative Examples

(12) Respective components were added according to composition shown in Table 1 below, followed by melting and kneading-extrusion, thereby preparing pellets. The prepared pellets were dried at 70 C. for 6 hours, followed by injection-molding, to manufacture specimens for evaluating physical properties.

(13) The components used in respective Examples and Comparative Examples are as follows.

(14) (A) Copolycarbonate resin (PC 8000-05, LG Chem.) according to Preparation Example 3 above

(15) (B) Bisphenol A polycarbonate resin (PC)

(16) The polycarbonate resin is a polymer of bisphenol A, and a melt index (MI) thereof was measured with a weight (g) measured for 10 minutes at a temperature of 300 and under a load of 1.2 kg according to ASTM D1238. As a result of the measurement, an aromatic polycarbonate resin having a melt index of 10 g/10 min and manufactured by LG Chem., was used.

(17) (C) Glass fiber

(18) (C-1) A glass fiber that had a width (D) of 28 m, a thickness of 7 m, a length (L) of 3 mm, and an aspect ratio () calculated by Equation 1 of 107, and was surface-treated with an epoxy silane-based compound and manufactured by Nittobo was used.

(19) (C-2) A glass fiber that had a diameter (D) of 10 to 13 m, a length (L) of 4 mm, and an aspect ratio () calculated by Equation 1 of 308 to 400, and was surface-treated with an epoxy silane-based compound and manufactured by Owens Corning was used.

(20) (D) Metablen S-2100 using a silicone-acrylate rubber manufactured by MRC in Japan was used as the impact-reinforcing agent of the rubber-modified vinyl-based graft copolymer.

(21) (E) Epoxy silane-based additive

(22) (E-1) Joncryl ADR 4370-F manufactured by BASF was used.

(23) (E-2) Silquest A-187 manufactured by Momentive was used.

(24) TABLE-US-00001 TABLE 1 Comparative Comparative Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Example 1 Example 2 (wt %) (wt %) (wt %) (wt %) (wt %) (wt %) (wt %) (wt %) A 30 30 30 92.8 30 30 30 B 62.8 62 37.8 62.8 62.8 67.8 92.8 C-1 5 5 30 5 5 5 C-2 5 D 2 2 2 2 2 2 2 2 E-1 0.2 1 0.2 0.2 0.2 0.2 0.2 E-2 0.2

Experimental Example

(25) Physical properties of each specimen formed from each composition of Examples and Comparative Examples were measured by the following methods, and results thereof were shown in Table 2 below.

(26) (1) Tensile strength: measured at 23 C. according to ASTM D638 using Instron UTM having a speed of 5 mm/sec.

(27) (2) Flexural strength/Flexural modulus: measured at 23 C. according to ASTM D790.

(28) (3) Impact strength (IZOD): measured at a temperature of 23 C. with inch (Notched Izod, J/m) according to ASTM D256.

(29) (4) Chemical resistance: the composition was pelletized using a twin-screw extruder attached with a vent of 40 mm, and was subjected to injection-molding at a cylinder temperature of 300 C. and a mold temperature of 80 C. DeletedTextsusing a N-20C injection molding machine (manufactured by JSW, Ltd.), thereby manufacturing each specimen. Eight points of the specimen having a smartphone size were designated, and were applied by spraying a liquid type sun screen (NIVEA Aqua Protect Sun Spray) for 0.5 seconds per each point. After the application, crack occurrence time was observed for 24 hours. Table 2 below showed chemical resistance evaluation results that were summarized with time at which crack occurrence began to be observed (time at which cracks began to occur at any of eight points), and when the crack occurrence was not observed for 24 hours, it was indicated as NC (No Crack).

(30) TABLE-US-00002 TABLE 2 Comparative Comparative Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Example 1 Example 2 Tensile 680 700 1200 680 670 680 560 700 Strength (kg/cm2) Flexural 1100 1200 1600 1100 1100 1100 900 1100 Strength (kg/cm2) Flexural 30000 32000 75000 30000 30000 30000 23000 30000 Modulus (Kg/cm2) Impact 20 20 15 20 23 20 20 18 Strength (kgcm/cm) Chemical NC NC NC NC NC NC 0.5 5 Resistance (Time)

(31) Referring to Table 2, it was confirmed that the molded articles of Examples exhibited strength and modulus equal to or higher than those of Comparative Examples and exhibited more excellent chemical resistance than those of Comparative Examples. In particular, it was confirmed that upon companion between Examples and Comparative Example 2, the impact strength was more improved in Examples when the same content of the glass fiber was included.