Polycarbonate and method of preparing the same

1. A polycarbonate comprising repeating units represented by Formula 1, Formula 2, Formula 3 and Formula 4, respectively:

wherein R 1 and R 2 are each independently substituted or unsubstituted C1 to C6 alkyl group, substituted or unsubstituted C3 to C6 cycloalkyl group, substituted or unsubstituted C6 to C12 aryl group or halogen atom, and a and b are each independently an integer from 0 to 4;

wherein R 1 and R 2 are each independently substituted or unsubstituted C1 to C6 alkyl group, substituted or unsubstituted C3 to C6 cycloalkyl group, substituted or unsubstituted C6 to C12 aryl group or halogen atom, and a and b are each independently an integer from 0 to 4;

wherein R 1 and R 2 are each independently substituted or unsubstituted C1 to C6 alkyl group, substituted or unsubstituted C3 to C6 cycloalkyl group, substituted or unsubstituted C6 to C12 aryl group or halogen atom, R 3 is substituted or unsubstituted C1 to C6 alkyl group, substituted or unsubstituted C6 to C12 aryl group, substituted or unsubstituted C7 to C20 aralkyl group, a and b are each independently an integer from 0 to 4, and n is 0 or 1; and

wherein R 1 and R 2 are each independently substituted or unsubstituted C1 to C6 alkyl group, substituted or unsubstituted C3 to C6 cycloalkyl group, substituted or unsubstituted C6 to C12 aryl group or halogen atom, R 3 is substituted or unsubstituted C1 to C6 alkyl group, substituted or unsubstituted C6 to C12 aryl group, substituted or unsubstituted C7 to C20 aralkyl group, a and b are each independently an integer from 0 to 4, and n is 0 or 1.

2. A polycarbonate containing about 1˜50 mol % of repeating units of Formula 4 based on the whole repeating units, and having a glass transition temperature of about 130 to about 190° C., a flame retardancy of V-0, as measured on a 3.2 mm thick specimen according to the UL-94, a notched IZOD impact strength of about 25 to about 120 kg·cm/cm, as measured on a ⅛″ thick specimen at room temperature according to ASTM D256, and a transmittance difference (ΔT) of about 12% or less, as calculated by the following Equation 1:

wherein R 1 and R 2 are each independently substituted or unsubstituted C1 to C6 alkyl group, substituted or unsubstituted C3 to C6 cycloalkyl group, substituted or unsubstituted C6 to C12 aryl group or halogen atom; R 3 is substituted or unsubstituted C1 to C6 alkyl group, substituted or unsubstituted C6 to C12 aryl group, substituted or unsubstituted C7 to C20 aralkyl group, a and b are each independently an integer from 0 to 4, and n is 0 or 1,

Δ

⁢

⁢

T

=

T

0

-

T

1

T

0

×

100

[

Equation

⁢

⁢

1

]

wherein, T 0 is initial visible light transmittance of a 2.5 mm thick sample, and T 1 is visible light transmittance of the sample obtained by immersing the sample in a solution consisting of methyl isobutyl ketone, cyclohexanone and 2-ethoxy ethanol for 2 minutes and then drying the sample at 80° C. for 30 minutes.

3. The polycarbonate as claimed in claim 1 , wherein the polycarbonate comprises repeating units of Formula 1 (M1), Formula 2 (M2), Formula 3 (M3) and Formula 4 (M4) in mole ratio of M1:M2:M3:M4=about 20˜90 mol %:about 5˜50 mol %:about 1˜50 mol %:about 1˜50 mol %:

wherein R 1 and R 2 are each independently substituted or unsubstituted C1 to C6 alkyl group, substituted or unsubstituted C3 to C6 cycloalkyl group, substituted or unsubstituted C6 to C12 aryl group or halogen atom, and a and b are each independently an integer from 0 to 4;

wherein R 1 and R 2 are each independently substituted or unsubstituted C1 to C6 alkyl group, substituted or unsubstituted C3 to C6 cycloalkyl group, substituted or unsubstituted C6 to C12 aryl group or halogen atom, and a and b are each independently an integer from 0 to 4;

wherein, R 1 and R 2 are each independently substituted or unsubstituted C1 to C6 alkyl group, substituted or unsubstituted C3 to C6 cycloalkyl group, substituted or unsubstituted C6 to C12 aryl group or halogen atom, R 3 is substituted or unsubstituted C1 to C6 alkyl group, substituted or unsubstituted C6 to C12 aryl group, substituted or unsubstituted C7 to C20 aralkyl group, a and b are each independently an integer from 0 to 4, and n is 0 or 1; and

wherein R 1 and R 2 are each independently substituted or unsubstituted C1 to C6 alkyl group, substituted or unsubstituted C3 to C6 cycloalkyl group, substituted or unsubstituted C6 to C12 aryl group or halogen atom, R 3 is substituted or unsubstituted C1 to C6 alkyl group, substituted or unsubstituted C6 to C12 aryl group, substituted or unsubstituted C7 to C20 aralkyl group, a and b are each independently an integer from 0 to 4, and n is 0 or 1.

4. A method of preparing polycarbonate, comprising transesterifying diols comprising Formula 1-1 and Formula 2-1 with carbonate ester and phosphate ester:

wherein R 1 and R 2 are each independently substituted or unsubstituted C1 to C6 alkyl group, substituted or unsubstituted C3 to C6 cycloalkyl group, substituted or unsubstituted C6 to C12 aryl group or halogen atom, and a and b are each independently an integer from 0 to 4; and

wherein R 1 and R 2 are each independently substituted or unsubstituted C1 to C6 alkyl group, substituted or unsubstituted C3 to C6 cycloalkyl group, substituted or unsubstituted C6 to C12 aryl group or halogen atom; and a and b are each independently an integer from 0 to 4.

5. The method as claimed in claim 4 , wherein the phosphate ester is at least one of aromatic phosphates and aromatic phosphonates.

6. The method as claimed in claim 4 , wherein the phosphate ester is represented by Formula 4-1:

wherein R 1 and R 2 are each independently C6 to C12 aryl group, or C6 to C12 aryl group substituted by C1 to C12; R 3 is substituted or unsubstituted C1 to C6 alkyl group, substituted or unsubstituted C6 to C12 aryl group, substituted or unsubstituted C7 to C20 aralkyl group; n is 0 or 1.

7. The method as claimed in claim 4 , wherein the mole ratio of Formula 1-1 to Formula 2-1 is about 60˜95 mol %: 5˜40 mol %.

8. The method as claimed in claim 4 , wherein the mole ratio of the carbonate esters to the phosphate esters is about 60˜99 mol %: 1˜40 mol %.

9. A thermoplastic resin composition comprising:

the polycarbonate of claim 1 ; and

a thermoplastic resin.

10. The thermoplastic resin composition as claimed in claim 9 , wherein the thermoplastic resin composition further comprises additives selected from the group consisting of antioxidants, nucleation agents, surfactants, coupling agents, fillers, plasticizers, lubricants, antimicrobial agents, release agents, heat stabilizers, light stabilizers, compatibilizers, inorganic additives, coloring agents, stabilizers, antistatic agents, pigments, dyes and flame proofing agents.

11. The polycarbonate as claimed in claim 2 , wherein the polycarbonate comprises repeating units of Formula 1 (M1), Formula 2 (M2), Formula 3 (M3) and Formula 4 (M4) in mole ratio of M1:M2:M3:M4=about 20˜90 mol %:about 5˜50 mol %:about 1˜50 mol %:about 1˜50 mol %:

wherein R 1 and R 2 are each independently substituted or unsubstituted C1 to C6 alkyl group, substituted or unsubstituted C3 to C6 cycloalkyl group, substituted or unsubstituted C6 to C12 aryl group or halogen atom, and a and b are each independently an integer from 0 to 4;

wherein R 1 and R 2 are each independently substituted or unsubstituted C1 to C6 alkyl group, substituted or unsubstituted C3 to C6 cycloalkyl group, substituted or unsubstituted C6 to C12 aryl group or halogen atom, and a and b are each independently an integer from 0 to 4;

wherein R 1 and R 2 are each independently substituted or unsubstituted C1 to C6 alkyl group, substituted or unsubstituted C3 to C6 cycloalkyl group, substituted or unsubstituted C6 to C12 aryl group or halogen atom, R 3 is substituted or unsubstituted C1 to C6 alkyl group, substituted or unsubstituted C6 to C12 aryl group, substituted or unsubstituted C7 to C20 aralkyl group, a and b are each independently an integer from 0 to 4, and n is 0 or 1; and

wherein R 1 and R 2 are each independently substituted or unsubstituted C1 to C6 alkyl group, substituted or unsubstituted C3 to C6 cycloalkyl group, substituted or unsubstituted C6 to C12 aryl group or halogen atom, R 3 is substituted or unsubstituted C1 to C6 alkyl group, substituted or unsubstituted C6 to C12 aryl group, substituted or unsubstituted C7 to C20 aralkyl group, a and b are each independently an integer from 0 to 4, and n is 0 or 1.

12. A thermoplastic resin composition comprising:

the polycarbonate of claim 2 ; and

a thermoplastic resin.

13. The thermoplastic resin composition as claimed in claim 12 , wherein the thermoplastic resin composition further comprises additives selected from the group consisting of antioxidants, nucleation agents, surfactants, coupling agents, fillers, plasticizers, lubricants, antimicrobial agents, release agents, heat stabilizers, light stabilizers, compatibilizers, inorganic additives, coloring agents, stabilizers, antistatic agents, pigments, dyes and flame proofing agents.